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Sample records for spinel cathode materials

  1. Nanostructured hybrid layered-spinel cathode material synthesized by hydrothermal method for lithium-ion batteries.

    PubMed

    Liu, Cong; Wang, Zhiyuan; Shi, Chunsheng; Liu, Enzuo; He, Chunnian; Zhao, Naiqin

    2014-06-11

    Nanostructured spinel LiMn1.5Ni0.5O4, layered Li1.5Mn0.75Ni0.25O2.5 and layered-spinel hybrid particles have been successfully synthesized by hydrothermal methods. It is found that the nanostructured hybrid cathode contains both spinel and layered components, which could be expressed as Li1.13Mn0.75Ni0.25O2.32. Diffraction-contrast bright-field (BF) and dark-field (DF) images illustrate that the hybrid cathode has well dispersed spinel component. Electrochemical measurements reveal that the first-cycle efficiency of the layered-spinel hybrid cathode is greatly improved (up to 90%) compared with that of the layered material (71%) by integrating spinel component. Our investigation demonstrates that the spinel containing hybrid material delivers a high capacity of 240 mAh g(-1) with good cycling stability between 2.0 and 4.8 V at a current rate of 0.1 C.

  2. Nature of the Electrochemical Properties of Sulphur Substituted LiMn₂O₄ Spinel Cathode Material Studied by Electrochemical Impedance Spectroscopy.

    PubMed

    Bakierska, Monika; Świętosławski, Michał; Dziembaj, Roman; Molenda, Marcin

    2016-08-16

    In this work, nanostructured LiMn₂O₄ (LMO) and LiMn₂O3.99S0.01 (LMOS1) spinel cathode materials were comprehensively investigated in terms of electrochemical properties. For this purpose, electrochemical impedance spectroscopy (EIS) measurements as a function of state of charge (SOC) were conducted on a representative charge and discharge cycle. The changes in the electrochemical performance of the stoichiometric and sulphur-substituted lithium manganese oxide spinels were examined, and suggested explanations for the observed dependencies were given. A strong influence of sulphur introduction into the spinel structure on the chemical stability and electrochemical characteristic was observed. It was demonstrated that the significant improvement in coulombic efficiency and capacity retention of lithium cell with LMOS1 active material arises from a more stable solid electrolyte interphase (SEI) layer. Based on EIS studies, the Li ion diffusion coefficients in the cathodes were estimated, and the influence of sulphur on Li⁺ diffusivity in the spinel structure was established. The obtained results support the assumption that sulphur substitution is an effective way to promote chemical stability and the electrochemical performance of LiMn₂O₄ cathode material.

  3. Facile preparation of core@shell and concentration-gradient spinel particles for Li-ion battery cathode materials

    PubMed Central

    Kozawa, Takahiro; Naito, Makio

    2015-01-01

    Core@shell and concentration-gradient particles have attracted much attention as improved cathodes for Li-ion batteries (LIBs). However, most of their preparation routes have employed a precisely-controlled co-precipitation method. Here, we report a facile preparation route of core@shell and concentration-gradient spinel particles by dry powder processing. The core@shell particles composed of the MnO2 core and the Li(Ni,Mn)2O4 spinel shell are prepared by mechanical treatment using an attrition-type mill, whereas the concentration-gradient spinel particles with an average composition of LiNi0.32Mn1.68O4 are produced by calcination of their core@shell particles as a precursor. The concentration-gradient LiNi0.32Mn1.68O4 spinel cathode exhibits the high discharge capacity of 135.3 mA h g−1, the wide-range plateau at a high voltage of 4.7 V and the cyclability with a capacity retention of 99.4% after 20 cycles. Thus, the facile preparation route of the core@shell and concentration-gradient particles may provide a new opportunity for the discovery and investigation of functional materials as well as for the cathode materials for LIBs. PMID:27877756

  4. Facile preparation of core@shell and concentration-gradient spinel particles for Li-ion battery cathode materials.

    PubMed

    Kozawa, Takahiro; Naito, Makio

    2015-02-01

    Core@shell and concentration-gradient particles have attracted much attention as improved cathodes for Li-ion batteries (LIBs). However, most of their preparation routes have employed a precisely-controlled co-precipitation method. Here, we report a facile preparation route of core@shell and concentration-gradient spinel particles by dry powder processing. The core@shell particles composed of the MnO2 core and the Li(Ni,Mn)2O4 spinel shell are prepared by mechanical treatment using an attrition-type mill, whereas the concentration-gradient spinel particles with an average composition of LiNi0.32Mn1.68O4 are produced by calcination of their core@shell particles as a precursor. The concentration-gradient LiNi0.32Mn1.68O4 spinel cathode exhibits the high discharge capacity of 135.3 mA h g(-1), the wide-range plateau at a high voltage of 4.7 V and the cyclability with a capacity retention of 99.4% after 20 cycles. Thus, the facile preparation route of the core@shell and concentration-gradient particles may provide a new opportunity for the discovery and investigation of functional materials as well as for the cathode materials for LIBs.

  5. Facile preparation of core@shell and concentration-gradient spinel particles for Li-ion battery cathode materials

    NASA Astrophysics Data System (ADS)

    Kozawa, Takahiro; Naito, Makio

    2015-02-01

    Core@shell and concentration-gradient particles have attracted much attention as improved cathodes for Li-ion batteries (LIBs). However, most of their preparation routes have employed a precisely-controlled co-precipitation method. Here, we report a facile preparation route of core@shell and concentration-gradient spinel particles by dry powder processing. The core@shell particles composed of the MnO2 core and the Li(Ni,Mn)2O4 spinel shell are prepared by mechanical treatment using an attrition-type mill, whereas the concentration-gradient spinel particles with an average composition of LiNi0.32Mn1.68O4 are produced by calcination of their core@shell particles as a precursor. The concentration-gradient LiNi0.32Mn1.68O4 spinel cathode exhibits the high discharge capacity of 135.3 mA h g-1, the wide-range plateau at a high voltage of 4.7 V and the cyclability with a capacity retention of 99.4% after 20 cycles. Thus, the facile preparation route of the core@shell and concentration-gradient particles may provide a new opportunity for the discovery and investigation of functional materials as well as for the cathode materials for LIBs.

  6. Polyaniline modification and performance enhancement of lithium-rich cathode material based on layered-spinel hybrid structure

    NASA Astrophysics Data System (ADS)

    Wang, Di; Wang, Xianyou; Yang, Xiukang; Yu, Ruizhi; Ge, Long; Shu, Hongbo

    2015-10-01

    The spherical lithium-rich cathode material with a layered-spinel hybrid structure is successfully synthesized and coated by polyaniline (PANI). The spherical material with layered-spinel hybrid structure is firstly prepared via the hydrothermal method, and then the conducting PANI is coated on the surface of the as-prepared spherical particle through an in-situ polymerization. Based on the analysis of scanning electron microscope (SEM), transmission electron microscope (TEM), high rate transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED), it can be found that the size distribution of the spherical particles modified by PANI are about ∼1 μm, meanwhile the average thickness of the PANI layer on the surface of each particle is about 6.3 nm. The electrochemical performance of the spherical lithium-rich cathode material modified by PANI is apparently improved, the capacity retention is still 92.4% after 200 cycles at a rate of 0.5 C. The discharge capacities at 0.1 C and 10 C are as high as 302.9 mAh g-1 and 146.2 mAh g-1, respectively. Therefore, the modification of PANI for the spherical lithium-rich cathode material with a layered-spinel hybrid structure will be a promising technical route for the application with high capacity, long cycle life and good safety.

  7. Dependence of structure and temperature for lithium-rich layered-spinel microspheres cathode material of lithium ion batteries.

    PubMed

    Wang, Di; Yu, Ruizhi; Wang, Xianyou; Ge, Long; Yang, Xiukang

    2015-02-12

    Homogeneous lithium-rich layered-spinel 0.5Li2MnO3·0.5LiMn1/3Ni1/3Co1/3O2 microspheres (~1 μm) are successfully prepared by a solvothermal method and subsequent high-temperature calcinations process. The effects of temperature on the structure and performance of the as-prepared cathode material are systemically studied by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), galvanostatical charge/discharge and electrochemical impedance spectra. The results show that a spinel Li4Mn5O12 component can be controllably introduced into the lithium-rich layered material at 750°C. Besides, it has been found that the obtained layered-spinel cathode material represents excellent electrochemical characteristics. For example, it can deliver a high initial discharge capacity of 289.6 mAh g(-1) between 2.0 V and 4.6 V at a rate of 0.1 C at room temperature, and a discharge capacity of 144.9 mAh g(-1) at 5 C and 122.8 mAh g(-1) even at 10 C. In addition, the retention of the capacity is still as high as 88% after 200 cycles, while only 79.9% for the single-phase layered material. The excellent electrochemical performance of the as-prepared cathode material can probably be attributed to the hybrid structures combining a fast Li-ion diffusion rate of 3D spinel Li4Mn5O12 phase and a high capacity of the layered Li-Mn-Ni-Co-O component.

  8. Dependence of structure and temperature for lithium-rich layered-spinel microspheres cathode material of lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Wang, Di; Yu, Ruizhi; Wang, Xianyou; Ge, Long; Yang, Xiukang

    2015-02-01

    Homogeneous lithium-rich layered-spinel 0.5Li2MnO3.0.5LiMn1/3Ni1/3Co1/3O2 microspheres (~1 μm) are successfully prepared by a solvothermal method and subsequent high-temperature calcinations process. The effects of temperature on the structure and performance of the as-prepared cathode material are systemically studied by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), galvanostatical charge/discharge and electrochemical impedance spectra. The results show that a spinel Li4Mn5O12 component can be controllably introduced into the lithium-rich layered material at 750°C. Besides, it has been found that the obtained layered-spinel cathode material represents excellent electrochemical characteristics. For example, it can deliver a high initial discharge capacity of 289.6 mAh g-1 between 2.0 V and 4.6 V at a rate of 0.1 C at room temperature, and a discharge capacity of 144.9 mAh g-1 at 5 C and 122.8 mAh g-1 even at 10 C. In addition, the retention of the capacity is still as high as 88% after 200 cycles, while only 79.9% for the single-phase layered material. The excellent electrochemical performance of the as-prepared cathode material can probably be attributed to the hybrid structures combining a fast Li-ion diffusion rate of 3D spinel Li4Mn5O12 phase and a high capacity of the layered Li-Mn-Ni-Co-O component.

  9. Dependence of structure and temperature for lithium-rich layered-spinel microspheres cathode material of lithium ion batteries

    PubMed Central

    Wang, Di; Yu, Ruizhi; Wang, Xianyou; Ge, Long; Yang, Xiukang

    2015-01-01

    Homogeneous lithium-rich layered-spinel 0.5Li2MnO3·0.5LiMn1/3Ni1/3Co1/3O2 microspheres (~1 μm) are successfully prepared by a solvothermal method and subsequent high-temperature calcinations process. The effects of temperature on the structure and performance of the as-prepared cathode material are systemically studied by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), galvanostatical charge/discharge and electrochemical impedance spectra. The results show that a spinel Li4Mn5O12 component can be controllably introduced into the lithium-rich layered material at 750°C. Besides, it has been found that the obtained layered-spinel cathode material represents excellent electrochemical characteristics. For example, it can deliver a high initial discharge capacity of 289.6 mAh g−1 between 2.0 V and 4.6 V at a rate of 0.1 C at room temperature, and a discharge capacity of 144.9 mAh g−1 at 5 C and 122.8 mAh g−1 even at 10 C. In addition, the retention of the capacity is still as high as 88% after 200 cycles, while only 79.9% for the single-phase layered material. The excellent electrochemical performance of the as-prepared cathode material can probably be attributed to the hybrid structures combining a fast Li-ion diffusion rate of 3D spinel Li4Mn5O12 phase and a high capacity of the layered Li-Mn-Ni-Co-O component. PMID:25672573

  10. About the Compatibility between High Voltage Spinel Cathode Materials and Solid Oxide Electrolytes as a Function of Temperature.

    PubMed

    Miara, Lincoln; Windmüller, Anna; Tsai, Chih-Long; Richards, William D; Ma, Qianli; Uhlenbruck, Sven; Guillon, Olivier; Ceder, Gerbrand

    2016-10-12

    The reactivity of mixtures of high voltage spinel cathode materials Li2NiMn3O8, Li2FeMn3O8, and LiCoMnO4 cosintered with Li1.5Al0.5Ti1.5(PO4)3 and Li6.6La3Zr1.6Ta0.4O12 electrolytes is studied by thermal analysis using X-ray-diffraction and differential thermoanalysis and thermogravimetry coupled with mass spectrometry. The results are compared with predicted decomposition reactions from first-principles calculations. Decomposition of the mixtures begins at 600 °C, significantly lower than the decomposition temperature of any component, especially the electrolytes. For the cathode + Li6.6La3Zr1.6Ta0.4O12 mixtures, lithium and oxygen from the electrolyte react with the cathodes to form highly stable Li2MnO3 and then decompose to form stable and often insulating phases such as La2Zr2O7, La2O3, La3TaO7, TiO2, and LaMnO3 which are likely to increase the interfacial impedance of a cathode composite. The decomposition reactions are identified with high fidelity by first-principles calculations. For the cathode + Li1.5Al0.5Ti1.5(PO4)3 mixtures, the Mn tends to oxidize to MnO2 or Mn2O3, supplying lithium to the electrolyte for the formation of Li3PO4 and metal phosphates such as AlPO4 and LiMPO4 (M = Mn, Ni). The results indicate that high temperature cosintering to form dense cathode composites between spinel cathodes and oxide electrolytes will produce high impedance interfacial products, complicating solid state battery manufacturing.

  11. Enhanced Electrochemical Performance of Layered Lithium-Rich Cathode Materials by Constructing Spinel-Structure Skin and Ferric Oxide Islands.

    PubMed

    Chen, Shi; Zheng, Yu; Lu, Yun; Su, Yuefeng; Bao, Liying; Li, Ning; Li, Yitong; Wang, Jing; Chen, Renjie; Wu, Feng

    2017-03-15

    Layered lithium-rich cathode materials have been considered as competitive candidates for advanced lithium-ion batteries because they are environmentally benign, high capacity (more than 250 mAh·g(-1)), and low cost. However, they still suffer from poor rate capability and modest cycling performance. To address these issues, we have proposed and constructed a spinel-structure skin and ferric oxide islands on the surface of layered lithium-rich cathode materials through a facile wet chemical method. During the surface modification, Li ions in the surface area of pristine particles could be partially extracted by H(+), along with the depositing process of ferric hydrogen. After calcination, the surface structure transformed to spinel structure, and ferric hydrogen was oxidized to ferric oxide. The as-designed surface structure was verified by EDX, HRTEM, XPS, and CV. The experimental results demonstrated that the rate performance and capacity retentions were significantly enhanced after such surface modification. The modified sample displayed a high discharge capacity of 166 mAh·g(-1) at a current density of 1250 mA·g(-1) and much more stable capacity retention of 84.0% after 50 cycles at 0.1C rate in contrast to 60.6% for pristine material. Our surface modification strategy, which combines the advantages of spinel structure and chemically inert ferric oxide nanoparticles, has been shown to be effective for realizing the layered lithium-rich cathodes with surface construction of fast ion diffusing capability as well as robust electrolyte corroding durability.

  12. Tailorable electrochemical performance of spinel cathode materials via in-situ integrating a layered Li2MnO3 phase for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Zhao, Jianqing; Wang, Hao; Xie, Zhiqiang; Ellis, Sara; Kuai, Xiaoxiao; Guo, Jun; Zhu, Xing; Wang, Ying; Gao, Lijun

    2016-11-01

    Electrochemical performances of spinel cathode materials have been evaluated in a broad voltage range of 2.0-4.8 V vs. Li/Li+ via in-situ integrating a layered Li2MnO3 phase for high-voltage and high-capacity lithium ion batteries. Effects of sintering temperatures on manipulating hybrid spinel-layered structures have been systematically studied during the decomposition of nonstoichiometric Li0.65Mn0.59Ni0.12Co0.13Oδ material. The spinel component undergoes a phase transition from an initial Li4Mn5O12-type to a LiMn1.5Ni0.5O4-type spinel structure under high temperatures above 700 °C; meanwhile the content of layered Li2MnO3 component is increased. Li2MnO3-stabilized spinel-layered cathodes can deliver the discharge capacity more than 225 mA h/g at 0.1 C and exhibit outstanding capacity retentions above 90% at 0.5 C (1 C = 250 mA/g) in an extended voltage range between 2.0 and 4.8 V. In addition to clarify significant Li2MnO3 impacts on improving cycling stability of spinel cathode materials, it is noticeable that LiMn1.5Ni0.5O4-based spinel materials can effectively suppress the electrochemical activation of the layered Li2MnO3 up to 4.8 V. This work sheds lights on tailoring hybrid structures and maximizing electrochemical performances of Li2MnO3-based spinel-layered cathode materials for superior lithium ion batteries.

  13. Understanding the effect of an in situ generated and integrated spinel phase on a layered Li-rich cathode material using a non-stoichiometric strategy.

    PubMed

    Zhang, Jicheng; Gao, Rui; Sun, Limei; Li, Zhengyao; Zhang, Heng; Hu, Zhongbo; Liu, Xiangfeng

    2016-09-14

    Recently, spinel-layered integrated Li-rich cathode materials have attracted great interest due to the large enhancement of their electrochemical performances. However, the modification mechanism and the effect of the integrated spinel phase on Li-rich layered cathode materials are still not very clear. Herein, we have successfully synthesized the spinel-layered integrated Li-rich cathode material using a facile non-stoichiometric strategy (NS-LNCMO). The rate capability (84 mA h g(-1)vs. 28 mA h g(-1), 10 C), cycling stability (92.4% vs. 80.5%, 0.2 C), low temperature electrochemical capability (96.5 mA h g(-1)vs. 59 mA h g(-1), -20 °C), initial coulomb efficiency (92% vs. 79%) and voltage fading (2.77 V vs. 3.02 V, 200 cycles@1 C) of spinel-layered integrated Li-rich cathode materials have been significantly improved compared with a pure Li-rich phase cathode. Some new insights into the effect of the integrated spinel phase on a layered Li-rich cathode have been proposed through a comparison of the structure evolution of the integrated and Li-rich only materials before and after cycling. The Li-ion diffusion coefficient of NS-LNCMO has been enlarged by about 3 times and almost does not change even after 100 cycles indicating an enhanced structure stability. The integration of the spinel phase not only enhances the structure stability of the layered Li-rich phase during charging-discharging but also expands the interslab spacing of the Li-ion diffusion layer, and elongates TM-O covalent bond lengths, which lowers the activation barrier of Li(+)-transportation, and alleviates the structure strain during the cycling procedure.

  14. Preliminary studies of biominerals-coated spinel LiMn2 O4 as a cathode material on electrochemical performances for Li-ion rechargeable batteries

    NASA Astrophysics Data System (ADS)

    Vediappan, Kumaran; Lee, Chang Woo

    2010-05-01

    Lithium manganese oxide (LiMn2O4) is an inexpensive and pollution-free cathode material for Li-ion rechargeable batteries. In this study, spinel LiMn2O4 cathode material was coated with biomineral powders by the mechano-chemical method. In the course of the material synthesis, citric acid and acryl amide were added to serve as a complexing agent and a gelling agent, respectively, followed by a calcination process at 700 °C for 6 h in a high-purity argon atmosphere. The spinel LiMn2O4 and biominerals-coated spinel LiMn2O4 cathode materials were, from diverse viewpoints, characterized by x-ray diffraction, field emission-scanning electron microscopy, Fourier transform infrared spectroscopy and the electrochemical cycling method to understand the mechanism of improvements in electrochemical performances. We suggest that the biominerals-coated spinel LiMn2O4 is a good candidate as a low cost and environmentally friendly cathode material showing the enlarged capacity characteristic of Li-ion rechargeable batteries.

  15. A facile approach to derive binder protective film on high voltage spinel cathode materials against high temperature degradation

    NASA Astrophysics Data System (ADS)

    Chou, Wei-Yu; Jin, Yi-Chun; Duh, Jenq-Gong; Lu, Cheng-Zhang; Liao, Shih-Chieh

    2015-11-01

    The electrochemical performance of spinel LiNi0.5Mn1.5O4 cathode combined with different binders at elevated temperature is firstly investigated. The water soluble binder, such as sodium carboxymethyl cellulose (CMC) and sodium alginate (SA), is compared with the polyvinylidene difluoride (PVdF) binder used in non-aqueous process. The aqueous process can meet the need of Li-ion battery industry due to environmental-friendly and cost effectiveness by replacing toxic organic solvent, such as N-methyl-pyrrolidone (NMP). In this study, a significantly improved high temperature cycling performance is successfully obtained as compared to the traditional PVdF binder. The aqueous binder can serve as a protective film which inhibits the serious Ni and Mn dissolution especially at elevated temperature. Our result demonstrates a facile approach to solve the problem of capacity fading for high voltage spinel cathodes.

  16. A series of spinel phase cathode materials prepared by a simple hydrothermal process for rechargeable lithium batteries

    NASA Astrophysics Data System (ADS)

    Liang, Yan-Yu; Bao, Shu-Juan; Li, Hu-Lin

    2006-07-01

    A series of spinel-structured materials have been prepared by a simple hydrothermal procedure in an aqueous medium. The new synthetic method is time and energy saving i.e., no further thermal treatment and extended grinding. The main experimental process involved the insertion of lithium into electrolytic manganese dioxide with glucose as a mild reductant in an autoclave. Both the hydrothermal temperature and the presence of glucose play the critical roles in determining the final spinel integrity. Particular electrochemical performance has also been systematically explored, and the results show that Al 3+, F - co-substituted spinels have the best combination of initial capacity and capacity retention among all these samples, exhibited the initial capacity of 115 mAh/g and maintained more than 90% of the initial value at the 50th cycle.

  17. A basic thin film study of spinel LiMn{sub 2}O{sub 4} as a possible cathode material for lithium secondary cells

    SciTech Connect

    Miura, Takashi; Kishi, Tomiya

    1995-12-31

    In a series of fundamental studies on the cathode active materials for a lithium secondary cell using geometrically well-defined sample electrodes, thin films of spinel LiMn{sub 2}O{sub 4} on a platinum plate were investigated in this work in an LiClO{sub 4}/propylene carbonate solution. These pyrolytically prepared films exhibit reversible extraction/insertion behavior for lithium under galvanostatic charge/discharge cycling between 4.3--3.5 V. The chemical diffusion coefficient of lithium in Li{sub x}Mn{sub 2}O{sub 4} determined by the galvanostatic intermittent titration technique (GITT) was in the order of 10{sup {minus}7}--10{sup {minus}10} cm{sup 2} {center_dot} s{sup {minus}1} within a spinel single-phase region of 0.6 < x < 1.0 and increased with increasing x.

  18. Influence of synthesis conditions on electrochemical properties of high-voltage Li 1.02Ni 0.5Mn 1.5O 4 spinel cathode material

    NASA Astrophysics Data System (ADS)

    Hwang, B. J.; Wu, Y. W.; Venkateswarlu, M.; Cheng, M. Y.; Santhanam, R.

    Li 1.02Ni 0.5Mn 1.5O 4 spinel cathode materials were successfully synthesized by a citric acid-assisted sol-gel method. The structure and morphology of the materials have been examined by X-ray diffraction and scanning electron microscopy, respectively. Electrochemical properties of the materials were investigated using cyclic voltammetry and galvanostatic charge/discharge measurements at two different temperatures (25 and 55 °C) using lithium anode. The initial capacity and capacity retention are highly dependent on the particle size, particle size distribution, crystallinity and purity of the materials. The Li 1.02Ni 0.5Mn 1.5O 4 materials synthesized both at 800 and 850 °C have shown best electrochemical performance in terms of capacity and capacity retention between 3.5 and 4.9 V with a LiPF 6 based electrolyte.

  19. High-performance spinel-rich Li1.5MnTiO4+δ ultralong nanofibers as cathode materials for Li-ion batteries.

    PubMed

    Hung Vu, Ngoc; Arunkumar, Paulraj; Bin Im, Won

    2017-03-31

    Recently, composite materials based on Li-Mn-Ti-O system were developed to target low cost and environmentally benign cathodes for Li-ion batteries. The spinel-layered Li1.5MnTiO4+δ bulk particles showed excellent cycle stability but poor rate performance. To address this drawback, ultralong nanofibers of a Li1.5MnTiO4+δ spinel-layered heterostructure were synthesized by electrospinning. Uniform nanofibers with diameters of about 80 nm were formed of tiny octahedral particles wrapped together into 30 μm long fibers. The Li1.5MnTiO4+δ nanofibers exhibited an improved rate capability compared to both Li1.5MnTiO4+δ nanoparticles and bulk particles. The uniform one-dimensional nanostructure of the composite cathode exhibited enhanced capacities of 235 and 170 mAh g(-1) at C/5 and 1 C rates, respectively. Its unique structure provided a large effective contact area for Li(+) diffusion, and low charge transfer resistance. Moreover, the layered phase contributed to its capacity in over 3 V region, which increased specific energy (726 Wh kg(-1)) compared to the bulk particles (534 Wh kg(-1)).

  20. Template-engaged synthesis of spinel-layered Li1.5MnTiO4+δ nanorods as a cathode material for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Vu, Ngoc Hung; Unithrattil, Sanjith; Hoang, Van Hien; Chun, Sangeun; Im, Won Bin

    2017-07-01

    Spinel-layered composites of Li1.5MnTiO4+δ were studied for their use as high-energy, low-cost, and environmentally benign cathode materials. The bulk particles showed an attractive specific capacity of up to 250 mAh g-1 at C/10. To improve the performance of this cathode at a high C-rate, a spinel-layered Li1.5MnTiO4+δ nanorod was successfully synthesized using a β-MnO2 nanorod template. The nanorod, which had an average diameter of 200 nm and a length of 1 μm, showed specific capacity as high as the bulk particle at C/10. However, owing to a one-dimensional nanostructure with a large effective contact area for Li+ diffusion, the nanorod sample exhibited enhanced capacities 11% (170 mAh g-1) and 167% higher (80 mAh g-1) at 1C and 10C rates, respectively, compared to the bulk particles. Moreover, both samples showed good cycle stability and capacity retention of over 85% after 100 cycles at 1C.

  1. High-performance spinel-rich Li1.5MnTiO4+δ ultralong nanofibers as cathode materials for Li-ion batteries

    PubMed Central

    Hung Vu, Ngoc; Arunkumar, Paulraj; Bin Im, Won

    2017-01-01

    Recently, composite materials based on Li-Mn-Ti-O system were developed to target low cost and environmentally benign cathodes for Li-ion batteries. The spinel-layered Li1.5MnTiO4+δ bulk particles showed excellent cycle stability but poor rate performance. To address this drawback, ultralong nanofibers of a Li1.5MnTiO4+δ spinel-layered heterostructure were synthesized by electrospinning. Uniform nanofibers with diameters of about 80 nm were formed of tiny octahedral particles wrapped together into 30 μm long fibers. The Li1.5MnTiO4+δ nanofibers exhibited an improved rate capability compared to both Li1.5MnTiO4+δ nanoparticles and bulk particles. The uniform one-dimensional nanostructure of the composite cathode exhibited enhanced capacities of 235 and 170 mAh g−1 at C/5 and 1 C rates, respectively. Its unique structure provided a large effective contact area for Li+ diffusion, and low charge transfer resistance. Moreover, the layered phase contributed to its capacity in over 3 V region, which increased specific energy (726 Wh kg−1) compared to the bulk particles (534 Wh kg−1). PMID:28361945

  2. High-performance spinel-rich Li1.5MnTiO4+δ ultralong nanofibers as cathode materials for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Hung Vu, Ngoc; Arunkumar, Paulraj; Bin Im, Won

    2017-03-01

    Recently, composite materials based on Li-Mn-Ti-O system were developed to target low cost and environmentally benign cathodes for Li-ion batteries. The spinel-layered Li1.5MnTiO4+δ bulk particles showed excellent cycle stability but poor rate performance. To address this drawback, ultralong nanofibers of a Li1.5MnTiO4+δ spinel-layered heterostructure were synthesized by electrospinning. Uniform nanofibers with diameters of about 80 nm were formed of tiny octahedral particles wrapped together into 30 μm long fibers. The Li1.5MnTiO4+δ nanofibers exhibited an improved rate capability compared to both Li1.5MnTiO4+δ nanoparticles and bulk particles. The uniform one-dimensional nanostructure of the composite cathode exhibited enhanced capacities of 235 and 170 mAh g-1 at C/5 and 1 C rates, respectively. Its unique structure provided a large effective contact area for Li+ diffusion, and low charge transfer resistance. Moreover, the layered phase contributed to its capacity in over 3 V region, which increased specific energy (726 Wh kg-1) compared to the bulk particles (534 Wh kg-1).

  3. Layered-Layered-Spinel Cathode Materials Prepared by a High-Energy Ball-Milling Process for Lithium-ion Batteries.

    PubMed

    Kim, Soo; Noh, Jae-Kyo; Aykol, Muratahan; Lu, Zhi; Kim, Haesik; Choi, Wonchang; Kim, Chunjoong; Chung, Kyung Yoon; Wolverton, Chris; Cho, Byung-Won

    2016-01-13

    In this work, we report the electrochemical properties of 0.5Li2MnO3·0.25LiNi0.5Co0.2Mn0.3O2·0.25LiNi0.5Mn1.5O4 and 0.333Li2MnO3·0.333LiNi0.5Co0.2Mn0.3O2·0.333LiNi0.5Mn1.5O4 layered-layered-spinel (L*LS) cathode materials prepared by a high-energy ball-milling process. Our L*LS cathode materials can deliver a large and stable capacity of ∼200 mAh g(-1) at high voltages up to 4.9 V, and do not show the anomalous capacity increase upon cycling observed in previously reported three-component cathode materials synthesized with different routes. Furthermore, we have performed synchrotron-based in situ X-ray diffraction measurements and found that there are no significant structural distortions during charge/discharge runs. Lastly, we carry out (opt-type) van der Waals-corrected density functional theory (DFT) calculations to explain the enhanced cycle characteristics and reduced phase transformations in our ball-milled L*LS cathode materials. Our simple synthesis method brings a new perspective on the use of the high-power L*LS cathodes in practical devices.

  4. Exploration of spinel LiCrTiO4 as the cathode material for rechargeable Mg-Li hybrid batteries.

    PubMed

    Yao, Ye; Zhang, Lu; Bie, Xiaofei; Chen, Hong; Wang, Chunzhong; Du, Fei; Chen, Gang

    2017-06-17

    Mg-Li hybrid batteries have attracted wide interest in recent years because of the potential safety as well as the cost benefit and high volumetric capacity. However, the slow kinetic properties strongly hinder their commercial application. In this study, we prepare spinel LiCrTiO4 by the solid-state reaction and conduct a comprehensive study on the improvement of its performance in Mg-Li hybrid batteries by optimizing the dual-salt electrolytes. It is found that LiCrTiO4 shows the reversible discharge/charge capacity of 178/169 mAh g-1 in the electrolyte of 1 M LiCl and 0.3 M APC (all-phenyl-complex). And when the concentration of APC increases to 0.4 M, LiCrTiO4 shows a high capacity retention of 95% after 30 cycles. In addition, no phase transition could be observed for the LiCrTiO4 electrode in dual-salts system, suggesting a highly electrochemical reversibility. Ex-situ EDX and SEM indicates that only Li+ ions are inserted into the cathode side, while Mg2+ ions reversibly deposit on the surface of Mg metal with no dendrite-like growth, indicative of good safety of Mg-Li hybrid batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Controllable synthesis of spinel lithium nickel manganese oxide cathode material with enhanced electrochemical performances through a modified oxalate co-precipitation method

    NASA Astrophysics Data System (ADS)

    Liu, Hongmei; Zhu, Guobin; Zhang, Li; Qu, Qunting; Shen, Ming; Zheng, Honghe

    2015-01-01

    A spinel lithium nickel manganese oxide (LiNi0.5Mn1.5O4) cathode material is synthesized with a modified oxalate co-precipitation method by controlling pH value of the precursor solution and introducing excessive Li source in the precursor. All the samples synthesized through this method are of Fd3m phase with a small amount of P4332 phase. It is found that pH value of the precursor solution considerably affects the morphology, stoichiometry and crystallographic structure of the target material, thereby resulting in different amounts of Mn3+ (i.e., different degree of disorder). 5% excessive Li source in the precursor may compensate for the lithium loss during the high-temperature sintering process and eliminate the LixNi1-xO impurity phase. Under the optimized synthesis conditions, the obtained high-purity LiNi0.5Mn1.5O4 spinel exhibits enhanced electrochemical performances. A reversible capacity of ca. 140 mAh g-1 can be delivered at 0.1C and the electrode retains 106 mAh g-1 at 10C rate. When cycled at 0.2C, a capacity retention of more than 98% is obtained in the initial 50 electrochemical cycles.

  6. Insight into the Atomic Structure of High-Voltage Spinel LiNi0.5Mn1.5O4 Cathode Material in the First Cycle

    DOE PAGES

    Huang, Xuejie; Yu, Xiqian; Lin, Mingxiang; ...

    2014-12-22

    Application of high-voltage spinel LiNi0.5Mn1.5O4 cathode material is the closest and the most realistic approach to meeting the midterm goal of lithium-ion batteries for electric vehicles (EVs) and plug-in hybrid electric vehicles (HEVs). However, this application has been hampered by long-standing issues, such as capacity degradation and poor first-cycle Coulombic efficiency of LiNi0.5Mn1.5O4 cathode material. Although it is well-known that the structure of LiNi0.5Mn1.5O4 into which Li ions are reversibly intercalated plays a critical role in the above issues, performance degradation related to structural changes, particularly in the first cycle, are not fully understood. Here, we report detailed investigations ofmore » local atomic-level and average structure of LiNi0.5Mn1.5O4 during first cycle (3.5–4.9 V) at room temperature. We observed two types of local atomic-level migration of transition metals (TM) ions in the cathode of a well-prepared LiNi0.5Mn1.5O4//Li half-cell during first charge via an aberration-corrected scanning transmission electron microscopy (STEM). Surface regions (~2 nm) of the cycled LiNi0.5Mn1.5O4 particles show migration of TM ions into tetrahedral Li sites to form a Mn3O4-like structure. However, subsurface regions of the cycled particles exhibit migration of TM ions into empty octahedral sites to form a rocksalt-like structure. The migration of these TM ions are closely related to dissolution of Ni/Mn ions and building-up of charge transfer impedance, which contribute significantly to the capacity degradation and the poor first-cycle Coulombic efficiency of spinel LiNi0.5Mn1.5O4 cathode material. Accordingly, we provide suggestions of effective stabilization of LiNi0.5Mn1.5O4 structure to obtain better electrochemical performance.« less

  7. Microwave-enhanced electrochemical cycling performance of the LiNi0.2Mn1.8O4 spinel cathode material at elevated temperature.

    PubMed

    Raju, Kumar; Nkosi, Funeka P; Viswanathan, Elumalai; Mathe, Mkhulu K; Damodaran, Krishnan; Ozoemena, Kenneth I

    2016-05-14

    The well-established poor electrochemical cycling performance of the LiMn2O4 (LMO) spinel cathode material for lithium-ion batteries at elevated temperature stems from the instability of the Mn(3+) concentration. In this work, a microwave-assisted solid-state reaction has been used to dope LMO with a very low amount of nickel (i.e., LiNi0.2Mn1.8O4, herein abbreviated as LMNO) for lithium-ion batteries from Mn3O4 which is prepared from electrolytic manganese oxide (EMD, γ-MnO2). To establish the impact of microwave irradiation on the electrochemical cycling performance at an elevated temperature (60 °C), the Mn(3+) concentration in the pristine and microwave-treated LMNO samples was independently confirmed by XRD, XPS, (6)LiMAS-NMR and electrochemical studies including electrochemical impedance spectroscopy (EIS). The microwave-treated sample (LMNOmic) allowed for the clear exposure of the {111} facets of the spinel, optimized the Mn(3+) content, promoting structural and cycle stability at elevated temperature. At room temperature, both the pristine (LMNO) and microwave-treated (LMNOmic) samples gave comparable cycling performance (>96% capacity retention and ca. 100% coulombic efficiency after 100 consecutive cycling). However, at an elevated temperature (60 °C), the LMNOmic gave an improved cycling stability (>80% capacity retention and ca. 90% coulombic efficiency after 100 consecutive cycling) compared to the LMNO. For the first time, the impact of microwave irradiation on tuning the average manganese redox state of the spinel material to enhance the cycling performance of the LiNi0.2Mn1.8O4 at elevated temperature and lithium-ion diffusion kinetics has been clearly demonstrated.

  8. Sub-2 nm Thick Fluoroalkylsilane Self-Assembled Monolayer-Coated High Voltage Spinel Crystals as Promising Cathode Materials for Lithium Ion Batteries

    NASA Astrophysics Data System (ADS)

    Zettsu, Nobuyuki; Kida, Satoru; Uchida, Shuhei; Teshima, Katsuya

    2016-08-01

    We demonstrate herein that an ultra-thin fluoroalkylsilane self-assembled monolayer coating can be used as a modifying agent at LiNi0.5Mn1.5O4‑δcathode/electrolyte interfaces in 5V-class lithium-ion batteries. Bare LiNi0.5Mn1.5O4‑δ cathode showed substantial capacity fading, with capacity dropping to 79% of the original capacity after 100 cycles at a rate of 1C, which was entirely due to dissolution of Mn3+ from the spinel lattice via oxidative decomposition of the organic electrolyte. Capacity retention was improved to 97% on coating ultra-thin FAS17-SAM onto the LiNi0.5Mn1.5O4 cathode surface. Such surface protection with highly ordered fluoroalkyl chains insulated the cathode from direct contact with the organic electrolyte and led to increased tolerance to HF.

  9. Preparation of Layered-Spinel Microsphere/Reduced Graphene Oxide Cathode Materials for Ultrafast Charge-Discharge Lithium-Ion Batteries.

    PubMed

    Luo, Dong; Fang, Shaohua; Yang, Li; Hirano, Shin-Ichi

    2017-07-17

    Although Li-rich layered oxides (LLOs) have the highest capacity of any cathodes used, the rate capability of LLOs falls short of meeting the requirements of electric vehicles and smart grids. Herein, a layered-spinel microsphere/reduced graphene oxide heterostructured cathode (LS@rGO) is prepared in situ. This cathode is composed of a spinel phase, two layered structures, and a small amount of reduced graphene oxide (1.08 wt % of carbon). The assembly delivers a considerable charge capacity (145 mA h g(-1) ) at an ultrahigh charge- discharge rate of 60 C (12 A g(-1) ). The rate capability of LS@rGO is influenced by the introduced spinel phase and rGO. X-ray absorption and X-ray photoelectron spectroscopy data indicate that Cr ions move from octahedral lattice sites to tetrahedral lattice sites, and that Mn ions do not participate in the oxidation reaction during the initial charge process. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Influence of particle sizes and morphologies on the electrochemical performances of spinel LiMn2O4 cathode materials

    NASA Astrophysics Data System (ADS)

    Xiao, Liang; Guo, Yonglin; Qu, Deyu; Deng, Bohua; Liu, Hanxing; Tang, Daoping

    2013-03-01

    Monodispersed and uniform cubic LiMn2O4 with side length of 5.0 μm denoted as CB and spherical LiMn2O4 with different diameters (2.0, 3.5, 8.0 μm) denoted as SS, MS, BS respectively are prepared through a controllable precipitation of precursors MnCO3 and a followed melt-impregnation process. Studies show that the electrochemical performance of LiMn2O4 samples with spherical morphology are better than those of the cubic one. Moreover, the spherical LiMn2O4 (MS) with middle size (3.5 μm in diameter) has the best electrochemical performance among three spherical samples instead of the smallest spherical LiMn2O4. The determined apparent lithium ion diffusion coefficients of prepared samples decrease in the order of MS > SS > BS > CB and their values are in the range of 10-9.5-10-11.5 cm2 s-1 and 10-8.0-10-10.5 cm2 s-1 from PITT and CITT respectively. This trend matched well with the electrochemical performances of the four cathode materials. This observation can be addressed to the fact that the middle size spherical particles balance the contradictory of diffusion length in solid phase and particle agglomeration, which lead to perfect contacts with the conductive additive, considerable apparent Li-ion diffusion rate and the best performance of MS LiMn2O4.

  11. Spinel compounds as multivalent battery cathodes: A systematic evaluation based on ab initio calculations

    DOE PAGES

    Liu, Miao; Rong, Ziqin; Malik, Rahul; ...

    2014-12-16

    In this study, batteries that shuttle multivalent ions such as Mg2+ and Ca2+ ions are promising candidates for achieving higher energy density than available with current Li-ion technology. Finding electrode materials that reversibly store and release these multivalent cations is considered a major challenge for enabling such multivalent battery technology. In this paper, we use recent advances in high-throughput first-principles calculations to systematically evaluate the performance of compounds with the spinel structure as multivalent intercalation cathode materials, spanning a matrix of five different intercalating ions and seven transition metal redox active cations. We estimate the insertion voltage, capacity, thermodynamic stabilitymore » of charged and discharged states, as well as the intercalating ion mobility and use these properties to evaluate promising directions. Our calculations indicate that the Mn2O4 spinel phase based on Mg and Ca are feasible cathode materials. In general, we find that multivalent cathodes exhibit lower voltages compared to Li cathodes; the voltages of Ca spinels are ~0.2 V higher than those of Mg compounds (versus their corresponding metals), and the voltages of Mg compounds are ~1.4 V higher than Zn compounds; consequently, Ca and Mg spinels exhibit the highest energy densities amongst all the multivalent cation species. The activation barrier for the Al³⁺ ion migration in the Mn₂O₄ spinel is very high (~1400 meV for Al3+ in the dilute limit); thus, the use of an Al based Mn spinel intercalation cathode is unlikely. Amongst the choice of transition metals, Mn-based spinel structures rank highest when balancing all the considered properties.« less

  12. Synthesis of spinel LiMn2O4 cathode material by a modified solid state reaction

    NASA Astrophysics Data System (ADS)

    Zhang, Jiawei; Lin, Shudong; Li, Keyan; Shua, Fenfen; Chen, Kunfeng; Wang, Liqiu; Xue, Dongfeng

    2015-12-01

    Spinel LiMn2O4 was synthesized by a modified solid state reaction. We pretreated the reactants using tartaric acid as complexing agent through a grinding process to obtain uniform distribution of metal ions at atomic level. The structures, morphologies and electrochemical properties of the products were studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and galvanostatic charge-discharge test. The results show that adding tartaric acid during the chemical pretreatment plays an important role in the formation of regular and uniform particles, which is beneficial to the electrochemical performance of LiMn2O4. At the current density of 100 mA g-1, the discharge capacity is 118 mAh g-1 after 50 cycles with the capacity retention of 97%.

  13. Sub-2 nm Thick Fluoroalkylsilane Self-Assembled Monolayer-Coated High Voltage Spinel Crystals as Promising Cathode Materials for Lithium Ion Batteries

    PubMed Central

    Zettsu, Nobuyuki; Kida, Satoru; Uchida, Shuhei; Teshima, Katsuya

    2016-01-01

    We demonstrate herein that an ultra-thin fluoroalkylsilane self-assembled monolayer coating can be used as a modifying agent at LiNi0.5Mn1.5O4−δcathode/electrolyte interfaces in 5V-class lithium-ion batteries. Bare LiNi0.5Mn1.5O4−δ cathode showed substantial capacity fading, with capacity dropping to 79% of the original capacity after 100 cycles at a rate of 1C, which was entirely due to dissolution of Mn3+ from the spinel lattice via oxidative decomposition of the organic electrolyte. Capacity retention was improved to 97% on coating ultra-thin FAS17-SAM onto the LiNi0.5Mn1.5O4 cathode surface. Such surface protection with highly ordered fluoroalkyl chains insulated the cathode from direct contact with the organic electrolyte and led to increased tolerance to HF. PMID:27553901

  14. Long-term evaluation of solid oxide fuel cell candidate materials in a 3-cell generic stack test fixture, part III: Stability and microstructure of Ce-(Mn,Co)-spinel coating, AISI441 interconnect, alumina coating, cathode and anode

    NASA Astrophysics Data System (ADS)

    Chou, Yeong-Shyung; Stevenson, Jeffry W.; Choi, Jung-Pyung

    2014-07-01

    A generic solid oxide fuel cell stack test fixture was developed to evaluate candidate materials and processing under realistic conditions. Part III of the work investigated the stability of Ce-(Mn,Co) spinel coating, AISI441 metallic interconnect, alumina coating, and cell's degradation. After 6000 h test, the spinel coating showed densification with some diffusion of Cr. At the metal interface, segregation of Si and Ti was observed, however, no continuous layer formed. The alumina coating for perimeter sealing areas appeared more dense and thick at the air side than the fuel side. Both the spinel and alumina coatings remained bonded. EDS analysis of Cr within the metal showed small decrease in concentration near the coating interface and would expect to cause no issue of Cr depletion. Inter-diffusion of Ni, Fe, and Cr between spot-welded Ni wire and AISI441 interconnect was observed and Cr-oxide scale formed along the circumference of the weld. The microstructure of the anode and cathode was discussed relating to degradation of the top and middle cells. Overall, the Ce-(Mn,Co) spinel coating, alumina coating, and AISI441 steel showed the desired long-term stability and the developed generic stack fixture proved to be a useful tool to validate candidate materials for SOFC.

  15. Truncated octahedral LiNi0.5Mn1.5O4 cathode material for ultralong-life lithium-ion battery: Positive (100) surfaces in high-voltage spinel system

    NASA Astrophysics Data System (ADS)

    Liu, Haidong; Kloepsch, Richard; Wang, Jun; Winter, Martin; Li, Jie

    2015-12-01

    So far, it has not yet reached an agreement that (111) surfaces or (100) surfaces are more positive to electrochemical performance in the spinel system. Herein, we present the synthesis of regular truncated octahedral high-voltage spinel LiNi0.5Mn1.5O4 single crystals with preferred growth of (100) surfaces, which incredibly exhibit the best long-term cycling stability compared with the state-of-art spinel material. The capacity retention is about 90% after 2000 cycles at 1 C. The extraordinary performance is mostly attributed to the highly regular truncated octahedral microstructure with large portions of stable (100) facets, which can stabilize the spinel structure to effectively suppress the side reactions with the electrolyte at high operating voltage and are also orientated to support Li+ transport kinetics. Therefore, our work further promotes the practical application of LiNi0.5Mn1.5O4 cathode material in next generation Lithium-ion batteries with high energy density and power performance.

  16. Layered/Spinel Heterostructured and Hierarchical Micro/Nanostructured Li-Rich Cathode Materials with Enhanced Electrochemical Properties for Li-Ion Batteries.

    PubMed

    Deng, Ya-Ping; Yin, Zu-Wei; Wu, Zhen-Guo; Zhang, Shao-Jian; Fu, Fang; Zhang, Tao; Li, Jun-Tao; Huang, Ling; Sun, Shi-Gang

    2017-06-28

    Although holding a high capacity, Li-rich materials are far from the demand of practical market because of their inherent drawbacks, such as poor initial efficiency and rate capability. Herein, Li-rich materials of Li1.16Mn0.6Ni0.12Co0.12O2 have been prepared via a one-step solvothermal strategy. The detail characterizations demonstrate that the as-prepared materials present morphology of nanoparticle-aggregated hierarchical microspheres and a heterostructure of layered and Li4Mn5O12-type spinel components. Compared to materials of pure-layered structure, layered/spinel heterostructured materials exhibit simultaneously great reversible capacity (302 mAh g(-1) at 0.2 C), high initial Coulombic efficiency (94% at 0.2 C) and remarkable rate capability (193 mAh g(-1) at 10 C).

  17. Morphological Evolution of High-Voltage Spinel LiNi(0.5)Mn(1.5)O4 Cathode Materials for Lithium-Ion Batteries: The Critical Effects of Surface Orientations and Particle Size.

    PubMed

    Liu, Haidong; Wang, Jun; Zhang, Xiaofei; Zhou, Dong; Qi, Xin; Qiu, Bao; Fang, Jianhui; Kloepsch, Richard; Schumacher, Gerhard; Liu, Zhaoping; Li, Jie

    2016-02-01

    An evolution panorama of morphology and surface orientation of high-voltage spinel LiNi(0.5)Mn(1.5)O4 cathode materials synthesized by the combination of the microwave-assisted hydrothermal technique and a postcalcination process is presented. Nanoparticles, octahedral and truncated octahedral particles with different preferential growth of surface orientations are obtained. The structures of different materials are studied by X-ray diffraction (XRD), Raman spectroscopy, X-ray absorption near edge spectroscopy (XANES), and transmission electron microscopy (TEM). The influence of various morphologies (including surface orientations and particle size) on kinetic parameters, such as electronic conductivity and Li(+) diffusion coefficients, are investigated as well. Moreover, electrochemical measurements indicate that the morphological differences result in divergent rate capabilities and cycling performances. They reveal that appropriate surface-tailoring can satisfy simultaneously the compatibility of power capability and long cycle life. The morphology design for optimizing Li(+) transport and interfacial stability is very important for high-voltage spinel material. Overall, the crystal chemistry, kinetics and electrochemical performance of the present study on various morphologies of LiNi(0.5)Mn(1.5)O4 spinel materials have implications for understanding the complex impacts of electrode interface and electrolyte and rational design of rechargeable electrode materials for lithium-ion batteries. The outstanding performance of our truncated octahedral LiNi(0.5)Mn(1.5)O4 materials makes them promising as cathode materials to develop long-life, high energy and high power lithium-ion batteries.

  18. Hierarchical surface atomic structure of a manganese-based spinel cathode for lithium-ion batteries.

    PubMed

    Lee, Sanghan; Yoon, Gabin; Jeong, Minseul; Lee, Min-Joon; Kang, Kisuk; Cho, Jaephil

    2015-01-19

    The increasing use of lithium-ion batteries (LIBs) in high-power applications requires improvement of their high-temperature electrochemical performance, including their cyclability and rate capability. Spinel lithium manganese oxide (LiMn2O4) is a promising cathode material because of its high stability and abundance. However, it exhibits poor cycling performance at high temperatures owing to Mn dissolution. Herein we show that when stoichiometric lithium manganese oxide is coated with highly doped spinels, the resulting epitaxial coating has a hierarchical atomic structure consisting of cubic-spinel, tetragonal-spinel, and layered structures, and no interfacial phase is formed. In a practical application of the coating to doped spinel, the material retained 90% of its capacity after 800 cycles at 60 °C. Thus, the formation of an epitaxial coating with a hierarchical atomic structure could enhance the electrochemical performance of LIB cathode materials while preventing large losses in capacity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Surface stability of spinel MgNi0.5Mn1.5O4 and MgMn2O4 as cathode materials for magnesium ion batteries

    NASA Astrophysics Data System (ADS)

    Jin, Wei; Yin, Guangqiang; Wang, Zhiguo; Fu, Y. Q.

    2016-11-01

    Rechargeable ion batteries based on the intercalation of multivalent ions are attractive due to their high energy density and structural stability. Surface of cathode materials plays an important role for the electrochemical performance of the rechargeable ion batteries. In this work we calculated surface energies of (001), (110) and (111) facets with different terminations in spinel MgMn2O4 and MgNi0.5Mn1.5O4 cathodes. Results showed clearly that atomic reconstruction occurred due to surface relaxation. The surface energies for the (001), (110) and (111) surfaces of the MgNi0.5Mn1.5O4 were 0.08, 0.13 and 0.11 J/m2, respectively, whereas those of the Ni-doped MgMn2O4 showed less dependence on the surface structures.

  20. Prospects for spinel-stabilized, high-capacity lithium-ion battery cathodes

    NASA Astrophysics Data System (ADS)

    Croy, Jason R.; Park, Joong Sun; Shin, Youngho; Yonemoto, Bryan T.; Balasubramanian, Mahalingam; Long, Brandon R.; Ren, Yang; Thackeray, Michael M.

    2016-12-01

    Herein we report early results on efforts to optimize the electrochemical performance of a cathode composed of a lithium- and manganese-rich "layered-layered-spinel" (LLS) material for lithium-ion battery applications. Pre-pilot scale synthesis leads to improved particle properties compared with lab-scale efforts, resulting in high capacities (∼200 mAh g-1) and good energy densities (>700 Wh kgoxide-1) in tests with lithium-ion cells. Subsequent surface modifications give further improvements in rate capabilities and high-voltage stability. These results bode well for advances in the performance of this class of lithium- and manganese-rich cathode materials.

  1. A truncated octahedral spinel LiMn2O4 as high-performance cathode material for ultrafast and long-life lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Jiang, Caihua; Tang, Zilong; Wang, Shitong; Zhang, Zhongtai

    2017-07-01

    Spinel LiMn2O4 is a promising cathode candidate for lithium ion batteries whose electrochemical properties strongly depend on the surface orientation. In this work, we have successfully synthesized a high crystalline and well-defined truncated octahedral LiMn2O4 through the hydrothermal and heat treatment. The main {111} facets are aligned along the orientations mitigating Mn dissolution while the truncated {100} and {110} facets are along those facilitating Li+ diffusion. Benefiting from the unique structure, the octahedral LiMn2O4 delivers 143.4 mAh g-1 (close to the theoretical capacity of 148 mAh g-1) at 0.2 C and over 120 mAh g-1 at 30 C (discharged within 2 min) at 55 °C. Moreover, the fabricated LiMn2O4/Li4Ti5O12-TiO2 full cell demonstrates 121.6 mAh g-1 at 1 C and 56.0 mAh g-1 at 30 C with ∼81.2% capacity retention following 1000 cycles. The facilely synthesized truncated octahedral LiMn2O4 shows great potentials in practical applications for ultrafast and long-life lithium-ion batteries.

  2. Spinel compounds as multivalent battery cathodes: A systematic evaluation based on ab initio calculations

    SciTech Connect

    Liu, Miao; Rong, Ziqin; Malik, Rahul; Canepa, Pieremanuele; Jain, Anubhav; Ceder, Gerbrand; Persson, Kristin A.

    2014-12-16

    In this study, batteries that shuttle multivalent ions such as Mg2+ and Ca2+ ions are promising candidates for achieving higher energy density than available with current Li-ion technology. Finding electrode materials that reversibly store and release these multivalent cations is considered a major challenge for enabling such multivalent battery technology. In this paper, we use recent advances in high-throughput first-principles calculations to systematically evaluate the performance of compounds with the spinel structure as multivalent intercalation cathode materials, spanning a matrix of five different intercalating ions and seven transition metal redox active cations. We estimate the insertion voltage, capacity, thermodynamic stability of charged and discharged states, as well as the intercalating ion mobility and use these properties to evaluate promising directions. Our calculations indicate that the Mn2O4 spinel phase based on Mg and Ca are feasible cathode materials. In general, we find that multivalent cathodes exhibit lower voltages compared to Li cathodes; the voltages of Ca spinels are ~0.2 V higher than those of Mg compounds (versus their corresponding metals), and the voltages of Mg compounds are ~1.4 V higher than Zn compounds; consequently, Ca and Mg spinels exhibit the highest energy densities amongst all the multivalent cation species. The activation barrier for the Al³⁺ ion migration in the Mn₂O₄ spinel is very high (~1400 meV for Al3+ in the dilute limit); thus, the use of an Al based Mn spinel intercalation cathode is unlikely. Amongst the choice of transition metals, Mn-based spinel structures rank highest when balancing all the considered properties.

  3. Formation Of The Spinel Phase In The Layered Composite Cathode Used In Li-Ion Batteries

    SciTech Connect

    Gu, Meng; Belharouak, Ilias; Zheng, Jianming; Wu, Huiming; Xiao, Jie; Genc, Arda; Amine, Khalil; Thevuthasan, Suntharampillai; Baer, Donald R.; Zhang, Jiguang; Browning, Nigel D.; Liu, Jun; Wang, Chong M.

    2013-01-22

    Pristine Li-rich layered cathodes, such as Li1.2Ni0.2Mn0.6O2 and Li1.2Ni0.1Mn0.525Co0.175O2, were identified to exist in two different structures: LiMO2 R-3m and Li2MO3 C2/m phases. Upon charge/discharge cycling, both phases gradually transform to the spinel structure. The transition from LiMO2 R-3m to spinel is accomplished through the migration of transition metal ions to the Li site without breaking down the lattice, leading to the formation of mosaic structured spinel grains within the parent particle. In contrast, transition from Li2MO3 C2/m to spinel involves removal of Li+ and O2-, which produces a large lattice strain and leads to the breakdown of the parent lattice and therefore the newly formed spinel grains show random orientation within the same particle. Cracks and pores were also noticed within some particles, which is believed to be the consequence of the breakdown of the lattice and vacancy condensation upon removal of lithium ions. The presently observed structure transition characteristics provide direct reasons for the observed gradual capacity loss and poor rate performance of the layered composite. Ultimately it also provides clues about how to improve the materials structure with potential improved performance.

  4. Insight into the Atomic Structure of High-Voltage Spinel LiNi0.5Mn1.5O4 Cathode Material in the First Cycle

    SciTech Connect

    Huang, Xuejie; Yu, Xiqian; Lin, Mingxiang; Ben, Liubin; Sun, Yang; Wang, Hao; Yang, Zhenzhong; Gu, Lin; Yang, Xiao -Qing; Zhao, Haofei; Yu, Richeng; Armand, Michel

    2014-12-22

    Application of high-voltage spinel LiNi0.5Mn1.5O4 cathode material is the closest and the most realistic approach to meeting the midterm goal of lithium-ion batteries for electric vehicles (EVs) and plug-in hybrid electric vehicles (HEVs). However, this application has been hampered by long-standing issues, such as capacity degradation and poor first-cycle Coulombic efficiency of LiNi0.5Mn1.5O4 cathode material. Although it is well-known that the structure of LiNi0.5Mn1.5O4 into which Li ions are reversibly intercalated plays a critical role in the above issues, performance degradation related to structural changes, particularly in the first cycle, are not fully understood. Here, we report detailed investigations of local atomic-level and average structure of LiNi0.5Mn1.5O4 during first cycle (3.5–4.9 V) at room temperature. We observed two types of local atomic-level migration of transition metals (TM) ions in the cathode of a well-prepared LiNi0.5Mn1.5O4//Li half-cell during first charge via an aberration-corrected scanning transmission electron microscopy (STEM). Surface regions (~2 nm) of the cycled LiNi0.5Mn1.5O4 particles show migration of TM ions into tetrahedral Li sites to form a Mn3O4-like structure. However, subsurface regions of the cycled particles exhibit migration of TM ions into empty octahedral sites to form a rocksalt-like structure. The migration of these TM ions are closely related to dissolution of Ni/Mn ions and building-up of charge transfer impedance, which contribute significantly to the capacity degradation and the poor first-cycle Coulombic efficiency of spinel LiNi0.5Mn1.5O4 cathode material. Accordingly, we provide suggestions of effective stabilization of LiNi0.5

  5. Formation of the spinel phase in the layered composite cathode used in Li-ion batteries.

    PubMed

    Gu, Meng; Belharouak, Ilias; Zheng, Jianming; Wu, Huiming; Xiao, Jie; Genc, Arda; Amine, Khalil; Thevuthasan, Suntharampillai; Baer, Donald R; Zhang, Ji-Guang; Browning, Nigel D; Liu, Jun; Wang, Chongmin

    2013-01-22

    Pristine Li-rich layered cathodes, such as Li(1.2)Ni(0.2)Mn(0.6)O(2) and Li(1.2)Ni(0.1)Mn(0.525)Co(0.175)O(2), were identified to exist in two different structures: LiMO(2)R3[overline]m and Li(2)MO(3)C2/m phases. Upon 300 cycles of charge/discharge, both phases gradually transform to the spinel structure. The transition from LiMO(2)R3[overline]m to spinel is accomplished through the migration of transition metal ions to the Li site without breaking down the lattice, leading to the formation of mosaic structured spinel grains within the parent particle. In contrast, transition from Li(2)MO(3)C2/m to spinel involves removal of Li(+) and O(2-), which produces large lattice strain and leads to the breakdown of the parent lattice. The newly formed spinel grains show random orientation within the same particle. Cracks and pores were also noticed within some layered nanoparticles after cycling, which is believed to be the consequence of the lattice breakdown and vacancy condensation upon removal of lithium ions. The AlF(3)-coating can partially relieve the spinel formation in the layered structure during cycling, resulting in a slower capacity decay. However, the AlF(3)-coating on the layered structure cannot ultimately stop the spinel formation. The observation of structure transition characteristics discussed in this paper provides direct explanation for the observed gradual capacity loss and poor rate performance of the layered composite. It also provides clues about how to improve the materials structure in order to improve electrochemical performance.

  6. Understanding Performance Differences from Various Synthesis Methods: A Case Study of Spinel LiCr0.2Ni0.4Mn1.4O4 Cathode Material.

    PubMed

    Chen, Mingzhe; Hu, Zhe; Wu, Zhenguo; Hua, Weibo; Ozawa, Kiyoshi; Gu, Qinfen; Kang, Yong-Mook; Guo, Xiaodong; Chou, Shu-Lei; Dou, Shi-Xue

    2016-10-05

    High voltage (5-V class) spinel LiCr0.2Ni0.4Mn1.4O4 is one of the most promising cathode materials to meet the energy requirements of lithium-ion batteries for electric vehicles and hybrid electric vehicles. For the mass production of this material (1 kg or higher), different synthesis routes will lead to different electrochemical performances, even with similar morphology and similar crystal structure obtained from laboratory X-ray diffraction, and the reason for this issue is still not clear. Herein, we have investigated the reasons for the different electrochemical performances resulting from three common synthesis routes (spray pyrolysis, coprecipitation, and sol-gel). Taking advantage of the high-resolution X-ray beam in synchrotron X-ray diffraction, we find that varying phase composition and the generated impurities, rather than the particle distribution, are likely to be the main reasons for the detected electrochemical variations. A higher amount of impurities will result in greater charge transfer resistance, inferior cycling stability, and more oxygen/lithium vacancies. Therefore, it is very important to obtain a deeper understanding with the help of higher-resolution X-rays and to provide better guidance for mass production of this cathode material for practical applications.

  7. Enhanced rate performance of molybdenum-doped spinel LiNi0.5Mn1.5O4 cathode materials for lithium ion battery

    NASA Astrophysics Data System (ADS)

    Yi, Ting-Feng; Chen, Bin; Zhu, Yan-Rong; Li, Xiao-Ya; Zhu, Rong-Sun

    2014-02-01

    The Mo-doped LiNi0.5Mn1.5O4 cathodes are successfully synthesized by citric acid-assisted sol-gel method. The result demonstrates that the Mo-doped LiMn1.4Ni0.55Mo0.05O4 cathodes present the improved electrochemical performance over pristine LiNi0.5Mn1.5O4. At the 2 C rate after 80 cycles, the discharge capacities are 68.5 mAh g-1 for the pristine LiNi0.5Mn1.5O4 material (53.9% of the capacity at 0.1 C), 107.4 mAh g-1 for the LiMn1.425Ni0.5Mo0.05O4 material (82.1% at 0.1 C), and 122.7 mAh g-1 for the LiMn1.4Ni0.55Mo0.05O4 material (90.5% at 0.1 C). Mo-doping is favorable for reducing the electrode polarization, suggesting that Mo-doped LiNi0.5Mn1.5O4 electrodes have faster lithium insertion/extraction kinetics during cycling. Mo-doped LiNi0.5Mn1.5O4 electrodes show lower charge-transfer resistance and higher lithium diffusion coefficients. In addition, LiMn1.4Ni0.55Mo0.05O4 cathode exhibits the smallest particle size, the lowest charge-transfer resistance and the highest lithium diffusion coefficient among all samples, indicating that it has a high reversibility and good rate capability.

  8. High-Capacity Layered-Spinel Cathodes for Li-Ion Batteries.

    PubMed

    Nayak, Prasant Kumar; Levi, Elena; Grinblat, Judith; Levi, Mikhael; Markovsky, Boris; Munichandraiah, N; Sun, Yang Kook; Aurbach, Doron

    2016-09-08

    Li and Mn-rich layered oxides with the general structure x Li2 MnO3 ⋅(1-x) LiMO2 (M=Ni, Mn, Co) are promising cathode materials for Li-ion batteries because of their high specific capacity, which may be greater than 250 mA h g(-1) . However, these materials suffer from high first-cycle irreversible capacity, gradual capacity fading, limited rate capability and discharge voltage decay upon cycling, which prevent their commercialization. The decrease in average discharge voltage is a major issue, which is ascribed to a structural layered-to-spinel transformation upon cycling of these oxide cathodes in wide potential ranges with an upper limit higher than 4.5 V and a lower limit below 3 V versus Li. By using four elements systems (Li, Mn, Ni, O) with appropriate stoichiometry, it is possible to prepare high capacity composite cathode materials that contain LiMn1.5 Ni0.5 O4 and Lix Mny Niz O2 components. The Li and Mn-rich layered-spinel cathode materials studied herein exhibit a high specific capacity (≥200 mA h g(-1) ) with good capacity retention upon cycling in a wide potential domain (2.4-4.9 V). The effect of constituent phases on their electrochemical performance, such as specific capacity, cycling stability, average discharge voltage, and rate capability, are explored here. This family of materials can provide high specific capacity, high rate capability, and promising cycle life. Using Co-free cathode materials is also an obvious advantage of these systems.

  9. An Integrated, Layered-Spinel Composite Cathode for Energy Storage Applications

    NASA Technical Reports Server (NTRS)

    Hagh, Nader; Skandan, Ganesh

    2012-01-01

    At low operating temperatures, commercially available electrode materials for lithium-ion batteries do not fully meet the energy and power requirements for NASA fs exploration activities. The composite cathode under development is projected to provide the required energy and power densities at low temperatures and its usage will considerably reduce the overall volume and weight of the battery pack. The newly developed composite electrode material can provide superior electrochemical performance relative to a commercially available lithium cobalt system. One advantage of using a composite cathode is its higher energy density, which can lead to smaller and lighter battery packs. In the current program, different series of layered-spinel composite materials with at least two different systems in an integrated structure were synthesized, and the volumetric and gravimetric energy densities were evaluated. In an integrated network of a composite electrode, the effect of the combined structures is to enhance the capacity and power capabilities of the material to levels greater than what is possible in current state-of-the-art cathode systems. The main objective of the current program is to implement a novel cathode material that meets NASA fs low temperature energy density requirements. An important feature of the composite cathode is that it has at least two components (e.g., layered and spinel) that are structurally integrated. The layered material by itself is electrochemically inactive; however, upon structural integration with a spinel material, the layered material can be electrochemically activated, thereby delivering a large amount of energy with stable cycling. A key aspect of the innovation has been the development of a scalable process to produce submicronand micron-scale particles of these composite materials. An additional advantage of using such a composite electrode material is its low irreversible loss (.5%), which is primarily due to the unique activation

  10. Utilizing environmental friendly iron as a substitution element in spinel structured cathode materials for safer high energy lithium-ion batteries

    DOE PAGES

    Hu, Enyuan; Bak, Seong -Min; Liu, Yijin; ...

    2015-12-03

    Suppressing oxygen release from lithium ion battery cathodes during heating is a critical issue for the improvement of the battery safety characteristics because oxygen can exothermically react with the flammable electrolyte and cause thermal runaway. Previous studies have shown that oxygen release can be reduced by the migration of transition metal cations from octahedral sites to tetrahedral sites during heating. Such site-preferred migration is determined by the electronic structure of cations. In addition, taking advantage of the unique electronic structure of the environmental friendly Fe, this is selected as substitution element in a high energy density material LiNi0.5Mn1.5O4 to improvemore » the thermal stability. The optimized LiNi0.33Mn1.33Fe0.33O4 material shows significantly improved thermal stability compared with the unsubstituted one, demonstrated by no observed oxygen release at temperatures as high as 500°C. Due to the electrochemical contribution of Fe, the high energy density feature of LiNi0.5Mn1.5O4 is well preserved.« less

  11. Utilizing environmental friendly iron as a substitution element in spinel structured cathode materials for safer high energy lithium-ion batteries

    SciTech Connect

    Hu, Enyuan; Bak, Seong -Min; Liu, Yijin; Liu, Jue; Yu, Xiqian; Zhou, Yong -Ning; Zhou, Jigang; Khalifah, Peter; Ariyoshi, Kingo; Nam, Kyung -Wan; Yang, Xiao -Qing

    2015-12-03

    Suppressing oxygen release from lithium ion battery cathodes during heating is a critical issue for the improvement of the battery safety characteristics because oxygen can exothermically react with the flammable electrolyte and cause thermal runaway. Previous studies have shown that oxygen release can be reduced by the migration of transition metal cations from octahedral sites to tetrahedral sites during heating. Such site-preferred migration is determined by the electronic structure of cations. In addition, taking advantage of the unique electronic structure of the environmental friendly Fe, this is selected as substitution element in a high energy density material LiNi0.5Mn1.5O4 to improve the thermal stability. The optimized LiNi0.33Mn1.33Fe0.33O4 material shows significantly improved thermal stability compared with the unsubstituted one, demonstrated by no observed oxygen release at temperatures as high as 500°C. Due to the electrochemical contribution of Fe, the high energy density feature of LiNi0.5Mn1.5O4 is well preserved.

  12. Cathode materials review

    SciTech Connect

    Daniel, Claus Mohanty, Debasish Li, Jianlin Wood, David L.

    2014-06-16

    The electrochemical potential of cathode materials defines the positive side of the terminal voltage of a battery. Traditionally, cathode materials are the energy-limiting or voltage-limiting electrode. One of the first electrochemical batteries, the voltaic pile invented by Alessandro Volta in 1800 (Phil. Trans. Roy. Soc. 90, 403-431) had a copper-zinc galvanic element with a terminal voltage of 0.76 V. Since then, the research community has increased capacity and voltage for primary (nonrechargeable) batteries and round-trip efficiency for secondary (rechargeable) batteries. Successful secondary batteries have been the lead-acid with a lead oxide cathode and a terminal voltage of 2.1 V and later the NiCd with a nickel(III) oxide-hydroxide cathode and a 1.2 V terminal voltage. The relatively low voltage of those aqueous systems and the low round-trip efficiency due to activation energies in the conversion reactions limited their use. In 1976, Wittingham (J. Electrochem. Soc., 123, 315) and Besenhard (J. Power Sources 1(3), 267) finally enabled highly reversible redox reactions by intercalation of lithium ions instead of by chemical conversion. In 1980, Goodenough and Mizushima (Mater. Res. Bull. 15, 783-789) demonstrated a high-energy and high-power LiCoO{sub 2} cathode, allowing for an increase of terminal voltage far beyond 3 V. Over the past four decades, the international research community has further developed cathode materials of many varieties. Current state-of-the-art cathodes demonstrate voltages beyond any known electrolyte stability window, bringing electrolyte research once again to the forefront of battery research.

  13. Cathode materials review

    NASA Astrophysics Data System (ADS)

    Daniel, Claus; Mohanty, Debasish; Li, Jianlin; Wood, David L.

    2014-06-01

    The electrochemical potential of cathode materials defines the positive side of the terminal voltage of a battery. Traditionally, cathode materials are the energy-limiting or voltage-limiting electrode. One of the first electrochemical batteries, the voltaic pile invented by Alessandro Volta in 1800 (Phil. Trans. Roy. Soc. 90, 403-431) had a copper-zinc galvanic element with a terminal voltage of 0.76 V. Since then, the research community has increased capacity and voltage for primary (nonrechargeable) batteries and round-trip efficiency for secondary (rechargeable) batteries. Successful secondary batteries have been the lead-acid with a lead oxide cathode and a terminal voltage of 2.1 V and later the NiCd with a nickel(III) oxide-hydroxide cathode and a 1.2 V terminal voltage. The relatively low voltage of those aqueous systems and the low round-trip efficiency due to activation energies in the conversion reactions limited their use. In 1976, Wittingham (J. Electrochem. Soc., 123, 315) and Besenhard (J. Power Sources 1(3), 267) finally enabled highly reversible redox reactions by intercalation of lithium ions instead of by chemical conversion. In 1980, Goodenough and Mizushima (Mater. Res. Bull. 15, 783-789) demonstrated a high-energy and high-power LiCoO2 cathode, allowing for an increase of terminal voltage far beyond 3 V. Over the past four decades, the international research community has further developed cathode materials of many varieties. Current state-of-the-art cathodes demonstrate voltages beyond any known electrolyte stability window, bringing electrolyte research once again to the forefront of battery research.

  14. Enhanced electrochemical performance of Li-rich layered cathode materials via chemical activation of Li2MnO3 component and formation of spinel/carbon coating layer

    NASA Astrophysics Data System (ADS)

    Pang, Shengli; Xu, Kaijie; Wang, Yonggang; Shen, Xiangqian; Wang, Wenzhi; Su, Yanjing; Zhu, Meng; Xi, Xiaoming

    2017-10-01

    Li-rich layered oxides are promising cathode materials for advanced Li-ion batteries because of their high specific capacity and operating potential. In this work, the Li-rich layered oxide Li1·2Mn0·54Ni0·13Co0·13O2 (LMNC), is modified via a carbonization-reduction process (yielding the corresponding reduced compound denoted LMNC-R). Compared to the pristine oxide, LMNC-R delivers significantly enhanced initial discharge capacity/columbic efficiency, remarkably improved rate performance with an accelerated Li+ diffusion rate, and significantly increased capacity/voltage retention. The specific energy density and energy retention after 100 cycles increase from 378.2 Wh kg-1 and 47.7% for LMNC to 572.0 Wh kg-1 and 71.3%, respectively, for LMNC-R. The enhancement in the electrochemical performance of LMNC-R can be attributed to the synchronous formation of the oxygen non-stoichiometric Li2MnO3-δ component and to the carbon/spinel double coating layer in the material that resulted from the post-treatment process. Thus, the carbonization-reduction modification process can be used to tailor the structural evolution procedure and to suppress the metal ion dissolution of the Li-rich layered oxide during cycling.

  15. Cathode material for lithium batteries

    DOEpatents

    Park, Sang-Ho; Amine, Khalil

    2013-07-23

    A method of manufacture an article of a cathode (positive electrode) material for lithium batteries. The cathode material is a lithium molybdenum composite transition metal oxide material and is prepared by mixing in a solid state an intermediate molybdenum composite transition metal oxide and a lithium source. The mixture is thermally treated to obtain the lithium molybdenum composite transition metal oxide cathode material.

  16. Cathode material for lithium batteries

    DOEpatents

    Park, Sang-Ho; Amine, Khalil

    2015-01-13

    A method of manufacture an article of a cathode (positive electrode) material for lithium batteries. The cathode material is a lithium molybdenum composite transition metal oxide material and is prepared by mixing in a solid state an intermediate molybdenum composite transition metal oxide and a lithium source. The mixture is thermally treated to obtain the lithium molybdenum composite transition metal oxide cathode material.

  17. Cation-substituted spinel oxide and oxyfluoride cathodes for lithium ion batteries

    DOEpatents

    Manthiram, Arumugam; Choi, Wongchang

    2014-05-13

    The present invention includes compositions and methods of making cation-substituted and fluorine-substituted spinel cathode compositions by firing a LiMn.sub.2-y-zLi.sub.yM.sub.zO.sub.4 oxide with NH.sub.4HF.sub.2 at low temperatures of between about 300 and 700.degree. C. for 2 to 8 hours and a .eta. of more than 0 and less than about 0.50, mixed two-phase compositions consisting of a spinel cathode and a layered oxide cathode, and coupling them with unmodified or surface modified graphite anodes in lithium ion cells.

  18. Relative stability of normal vs. inverse spinel for 3d transition metal oxides as lithium intercalation cathodes.

    PubMed

    Bhattacharya, Jishnu; Wolverton, C

    2013-05-07

    Spinel oxides represent an important class of cathode materials for Li-ion batteries. Two major variants of the spinel crystal structure are normal and inverse. The relative stability of normal and inverse ordering at different stages of lithiation has important consequences in lithium diffusivity, voltage, capacity retention and battery life. In this paper, we investigate the relative structural stability of normal and inverse structures of the 3d transition metal oxide spinels with first-principles DFT calculations. We have considered ternary spinel oxides LixM2O4 with M = Ti, V, Cr, Mn, Fe, Co and Ni in both lithiated (x = 1) and delithiated (x = 0) conditions. We find that for all lithiated spinels, the normal structure is preferred regardless of the metal. We observe that the normal structure for all these oxides has a lower size mismatch between octahedral cations compared to the inverse structure. With delithiation, many of the oxides undergo a change in stability with vanadium in particular, showing a tendency to occupy tetrahedral sites. We find that in the delithiated oxide, only vanadium ions can access a +5 oxidation state which prefers tetrahedral coordination. We have also calculated the average voltage of lithiation for these spinels. The calculated voltages agree well with the previously measured and calculated values, wherever available. For the yet to be characterized spinels, our calculation provides voltage values which can motivate further experimental attention. Lastly, we observe that all the normal spinel oxides of the 3d transition metal series have a driving force for a transformation to the non-spinel structure upon delithiation.

  19. Suppressing Manganese Dissolution from Lithium Manganese Oxide Spinel Cathodes with Single-Layer Graphene

    SciTech Connect

    Jaber-Ansari, Laila; Puntambekar, Kanan P.; Kim, Soo; Aykol, Muratahan; Luo, Langli; Wu, Jinsong; Myers, Benjamin D.; Iddir, Hakim; Russell, John T.; Saldana, Spencer J.; Kumar, Rajan; Thackeray, Michael M.; Curtiss, Larry A.; Dravid, Vinayak P.; Wolverton, Christopher M.; Hersam, Mark C.

    2015-06-24

    Spinel-structured LiMn 2 O 4 (LMO) is a desirable cathode material for Li-ion batteries due to its low cost, abundance, and high power capability. However, LMO suffers from limited cycle life that is triggered by manganese dissolution into the electrolyte during electrochemical cycling. Here, it is shown that single-layer graphene coatings suppress manganese dissolution, thus enhancing the performance and lifetime of LMO cathodes. Relative to lithium cells with uncoated LMO cathodes, cells with graphene-coated LMO cathodes provide improved capacity retention with enhanced cycling stability. X-ray photoelectron spectroscopy reveals that graphene coatings inhibit manganese depletion from the LMO surface. Additionally, transmission electron microscopy demonstrates that a stable solid electrolyte interphase is formed on graphene, which screens the LMO from direct contact with the electrolyte. Density functional theory calculations provide two mechanisms for the role of graphene in the suppression of manganese dissolution. First, common defects in single-layer graphene are found to allow the transport of lithium while concurrently acting as barriers for manganese diffusion. Second, graphene can chemically interact with Mn 3+ at the LMO electrode surface, promoting an oxidation state change to Mn 4+ , which suppresses dissolution.

  20. Fluorination Induced the Surface Segregation of High Voltage Spinel on Lithium-Rich Layered Cathodes for Enhanced Rate Capability in Lithium Ion Batteries.

    PubMed

    Jin, Yi-Chun; Duh, Jenq-Gong

    2016-02-17

    This study is aimed to explore the effect of fluoride doping and the associated structural transformation on lithium-rich layered cathode materials. The polymeric fluoride source is first adopted for synthesizing lithium intercalated oxide through a newly developed organic precipitation process. A heterostructured spinel/layered composite cathode material is obtained after appreciable fluorination and a superior rate capability is successfully achieved. The fluoride dopant amount and the surface spinel phase are evidenced and systematically examined by various structural spectroscopy and electrochemical analysis. It appears the reversible Ni(2+/4+) redox couple at high voltage regime around 4.8 V because of the formation of spinel LiNi1/2Mn3/2O4 phase. The mechanism of "layer to spinel" phase transformation is discussed in detail.

  1. Understanding the capacity fade mechanisms of spinel manganese oxide cathodes and improving their performance in lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Choi, Won Chang

    Lithium ion batteries have been successful in portable electronics market due to their high energy density, adopting the layered LiCoO2 as the cathode material in commercial lithium ion cells. However, increasing interest in lithium ion batteries for electric vehicle and hybrid electric vehicle applications requires alternative cathode materials due to the high cost, toxicity, and limited power capability of the layered LiCoO2 cathode. In this regard, spinel LiMn2O4 has become appealing as manganese is inexpensive and environmentally benign, but LiMn2O 4 is plagued by severe capacity fade at elevated temperatures. This dissertation explores the factors that control and limit the electrochemical performance of spinel LiMn2O4 cathodes and focuses on improving the performance parameters such as the capacity, cyclability, and rate capability of various spinel cathodes derived from LiMn2O 4. From a systematic investigation of a number of cationic and anionic (fluorine) substituted spinel oxide compositions, the improvements in electrochemical properties and performances are found to be due to the reduced manganese dissolution and suppressed lattice parameter difference between the two cubic phases formed during the charge-discharge process. Investigations focused on fluorine substitution reveal that spinel LiMn 2-y-zLiyZnzO4-etaFeta oxyfluoride cathodes synthesized by solid-state reactions at 800°C employing ZnF2 as a raw material and spinel LiMn2-y-zLiy NizO4-etaFeta oxyfluoride cathodes synthesized by firing the cation-substituted LiMn2-y-zLiy NizO4 oxides with NH4HF2 at a moderate temperature of 450°C show superior cyclability, increased capacity, reduced Mn dissolution, and excellent storage performance compared to the corresponding oxide analogs and the conventional LiMn2O 4. Spinel-layered composite cathodes are found to exhibit better electrochemical performance with graphite anode when charged to 4.7 V in the first cycle followed by cycling at 4.3--3.5 V

  2. Olivine Composite Cathode Materials for Improved Lithium Ion Battery Performance

    SciTech Connect

    Ward, R.M.; Vaughey, J.T.

    2006-01-01

    Composite cathode materials in lithium ion batteries have become the subject of a great amount of research recently as cost and safety issues related to LiCoO2 and other layered structures have been discovered. Alternatives to these layered materials include materials with the spinel and olivine structures, but these present different problems, e.g. spinels have low capacities and cycle poorly at elevated temperatures, and olivines exhibit extremely low intrinsic conductivity. Previous work has shown that composite structures containing spinel and layered materials have shown improved electrochemical properties. These types of composite structures have been studied in order to evaluate their performance and safety characteristics necessary for use in lithium ion batteries in portable electronic devices, particularly hybrid-electric vehicles. In this study, we extended that work to layered-olivine and spinel-olivine composites. These materials were synthesized from precursor salts using three methods: direct reaction, ball-milling, and a coreshell synthesis method. X-ray diffraction spectra and electrochemical cycling data show that the core-shell method was the most successful in forming the desired products. The electrochemical performance of the cells containing the composite cathodes varied dramatically, but the low overpotential and reasonable capacities of the spinel-olivine composites make them a promising class for the next generation of lithium ion battery cathodes.

  3. Mn oxidation state controllable spinel manganese-based intergrown cathode for excellent reversible lithium storage

    NASA Astrophysics Data System (ADS)

    Zhao, Quanqing; Wu, Yu; Ma, Xilan; Wang, Ran; Xu, Xingyan; Cao, Chuanbao

    2017-08-01

    Herein we report a novel hierarchical porous hollow cube-shaped 5 V spinel manganese-based intergrown cathode materials with controlling the average oxidation state of Mn. The equal proportion of LiNi0.5Mn1.5O4 and LiMn2O4 (LiMn1.75Ni0.25O4) intergrown cathode materials exhibit the most excellent electrochemical performance with the initial discharge capacity and energy density as high as 141.7 mAh g-1 and 627.8 Wh Kg-1 at 1 C. What's more, even though cells are performed at elevated temperature and encounter with intermittent high rate load, considerably superior cycle stabilities still are retained. The LMO/LNMO-1/1 yields the primal discharge capacity of 142.5 mAh g-1 and 140.8 mAh g-1, with 93.1% and 92.9% capacity retention up to 50 cycles at 55 °C and subjecting to intermittent 5 C discharge and charge load every five cycles, respectively.

  4. Cation-substituted spinel oxide and oxyfluoride cathodes for lithium ion batteries

    DOEpatents

    Manthiram, Arumugam; Choi, Wonchang

    2010-05-18

    The present invention includes compositions and methods of making cation-substituted and fluorine-substituted spinel cathode compositions by firing a LiMn2-y-zLiyMzO4 oxide with NH4HF2 at low temperatures of between about 300 and 700.degree. C. for 2 to 8 hours and a .eta. of more than 0 and less than about 0.50, mixed two-phase compositions consisting of a spinel cathode and a layered oxide cathode, and coupling them with unmodified or surface modified graphite anodes in lithium ion cells.

  5. A Spinel-integrated P2-type Layered Composite: High-rate Cathode for Sodium-ion Batteries

    SciTech Connect

    Zheng, Jianming; Yan, Pengfei; Kan, Wang Hay; Wang, Chong M.; Manthiram, Arumugam

    2016-01-14

    Sodium-ion batteries (SIB) are being intensively investigated, owing to the natural abundance and low cost of Na resources. However, the SIBs still suffer from poor rate capability due to the large ionic radius of Na+ ion and the significant kinetic barrier to Na+-ion transport. Here, we present an Fd-3m spinel-integrated P2-type layered composite (P2 + Fd-3m) material as a high-rate cathode for SIBs. The P2 + Fd-3m composite material Na0.50Ni1/6Co1/6Mn2/3O2 shows significantly enhanced discharge capacity, energy density, and rate capability as compared to the pure P2-type counterpart. The composite delivers a high capacity of 85 mA h g-1 when discharging at a very high current density of 1500 mA g-1 (10C rate) between 2.0 and 4.5 V, validating it as a promising cathode candidate for high-power SIBs. The superior performance is ascribed to the improved kinetics in the presence of the integrated-spinel phase, which facilitates fast electron transport to coordinate with the timely Na+-ion insertion/extraction. The findings of this work also shed light on the importance of developing lattice doping, surface coating, and electrolyte additives to further improve the structural and interfacial stability of P2-type cathode materials and fully realize their practical applications in sodium-ion batteries.

  6. Spinel LiMn2O4 nanorods as lithium ion battery cathodes.

    PubMed

    Kim, Do Kyung; Muralidharan, P; Lee, Hyun-Wook; Ruffo, Riccardo; Yang, Yuan; Chan, Candace K; Peng, Hailin; Huggins, Robert A; Cui, Yi

    2008-11-01

    Spinel LiMn2O4 is a low-cost, environmentally friendly, and highly abundant material for Li-ion battery cathodes. Here, we report the hydrothermal synthesis of single-crystalline beta-MnO2 nanorods and their chemical conversion into free-standing single-crystalline LiMn2O4 nanorods using a simple solid-state reaction. The LiMn2O4 nanorods have an average diameter of 130 nm and length of 1.2 microm. Galvanostatic battery testing showed that LiMn2O4 nanorods have a high charge storage capacity at high power rates compared with commercially available powders. More than 85% of the initial charge storage capacity was maintained for over 100 cycles. The structural transformation studies showed that the Li ions intercalated into the cubic phase of the LiMn2O4 with a small change of lattice parameter, followed by the coexistence of two nearly identical cubic phases in the potential range of 3.5 to 4.3 V.

  7. Facile Synthesis of Carbon-Coated Spinel Li4Ti5O12/Rutile-TiO2 Composites as an Improved Anode Material in Full Lithium-Ion Batteries with LiFePO4@N-Doped Carbon Cathode.

    PubMed

    Wang, Ping; Zhang, Geng; Cheng, Jian; You, Ya; Li, Yong-Ke; Ding, Cong; Gu, Jiang-Jiang; Zheng, Xin-Sheng; Zhang, Chao-Feng; Cao, Fei-Fei

    2017-02-22

    The spinel Li4Ti5O12/rutile-TiO2@carbon (LTO-RTO@C) composites were fabricated via a hydrothermal method combined with calcination treatment employing glucose as carbon source. The carbon coating layer and the in situ formed rutile-TiO2 can effectively enhance the electric conductivity and provide quick Li(+) diffusion pathways for Li4Ti5O12. When used as an anode material for lithium-ion batteries, the rate capability and cycling stability of LTO-RTO@C composites were improved in comparison with those of pure Li4Ti5O12 or Li4Ti5O12/rutile-TiO2. Moreover, the potential of approximately 1.8 V rechargeable full lithium-ion batteries has been achieved by utilizing an LTO-RTO@C anode and a LiFePO4@N-doped carbon cathode.

  8. Insertion of lattice strains into ordered LiNi0.5Mn1.5O4 spinel by mechanical stress: A comparison of perfect versus imperfect structures as a cathode for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Kozawa, Takahiro; Murakami, Takeshi; Naito, Makio

    2016-07-01

    The Ni-doped lithium manganese oxide, LiNi0.5Mn1.5O4, has received much attention as a cathode active material in high-energy lithium-ion batteries (LIBs). This active material has two different spinel structures depending on the ordering state of the Ni and Mn ions. The ordered LiNi0.5Mn1.5O4 spinel has an inferior cathode performance than the disordered phase because of its poor electronic conductivity. However, the ordered LiNi0.5Mn1.5O4 spinel possesses the potential advantage of avoiding dissolution of the Mn ion, which is an issue for the disordered spinel. The improvement of cathode performance is important for future applications. Here, we report a unique approach to improve the cathode performance of the ordered LiNi0.5Mn1.5O4 spinel. The mechanical treatment using an attrition-type mill successfully inserted lattice strains into the ordered LiNi0.5Mn1.5O4 spinel structure without a phase transformation to the disordered phase. The insertion of lattice strains by mechanical stresses provided an increased discharge capacity and a decreased charge transfer resistance. This limited crystal structure modification improved the cathode performance. The present work has the potential for application of the mechanically treated ordered LiNi0.5Mn1.5O4 spinel as a cathode for high-energy LIBs.

  9. Enhancement of electrochemical performance by simultaneous substitution of Ni and Mn with Fe in Ni-Mn spinel cathodes for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Kiziltas-Yavuz, Nilüfer; Yavuz, Murat; Indris, Sylvio; Bramnik, Natalia N.; Knapp, Michael; Dolotko, Oleksandr; Das, Bijoy; Ehrenberg, Helmut; Bhaskar, Aiswarya

    2016-09-01

    LiNi0.5-xFe2xMn1.5-xO4 (x = 0, 0.1, 0.15, 0.2) spinel cathode materials are synthesized using citric acid-assisted sol-gel method with final calcination temperature of 1000 °C. The structure and morphology of the materials are characterized by using synchrotron and neutron powder diffraction as well as scanning electron microscopy. Different from the parent LiNi0.5Mn1.5O4 (LNMO) material, the Fe-doped spinels do not contain a rock-salt type impurity phase. However, they contain additional layered (C2/m) and spinel Fe3O4 (Fd 3 bar m) phases in small amounts. The substitution of Fe into the spinel structure has been confirmed by Mössbauer spectroscopy. The Fe-doped spinels exhibit improved cycling stability (with a C/2 charge-discharge rate) and rate capability compared to the parent LNMO at room temperature in a voltage range 3.5-5.0 V. Among all these samples, the composition LiNi0.4Fe0.2Mn1.4O4 shows the best room temperature cycling stability (capacity retention of 92% after 300 cycles) as well as the highest initial discharge capacity (134 mAh g-1). The delivered capacities at high C-rates (especially at 10C and 20C) with respect to the capacity delivered at C/2 are higher for all Fe-doped samples compared to the parent LNMO. Furthermore, Fe-doping improves the thermal stability of the Ni-Mn spinels in the delithiated state.

  10. Cation-Deficient Spinel ZnMn2O4 Cathode in Zn(CF3SO3)2 Electrolyte for Rechargeable Aqueous Zn-Ion Battery.

    PubMed

    Zhang, Ning; Cheng, Fangyi; Liu, Yongchang; Zhao, Qing; Lei, Kaixiang; Chen, Chengcheng; Liu, Xiaosong; Chen, Jun

    2016-10-05

    Rechargeable aqueous Zn-ion batteries are attractive cheap, safe and green energy storage technologies but are bottlenecked by limitation in high-capacity cathode and compatible electrolyte to achieve satisfactory cyclability. Here we report the application of nonstoichiometric ZnMn2O4/carbon composite as a new Zn-insertion cathode material in aqueous Zn(CF3SO3)2 electrolyte. In 3 M Zn(CF3SO3)2 solution that enables ∼100% Zn plating/stripping efficiency with long-term stability and suppresses Mn dissolution, the spinel/carbon hybrid exhibits a reversible capacity of 150 mAh g(-1) and a capacity retention of 94% over 500 cycles at a high rate of 500 mA g(-1). The remarkable electrode performance results from the facile charge transfer and Zn insertion in the structurally robust spinel featuring small particle size and abundant cation vacancies, as evidenced by combined electrochemical measurements, XRD, Raman, synchrotron X-ray absorption spectroscopy, FTIR, and NMR analysis. The results would enlighten and promote the use of cation-defective spinel compounds and trifluoromethanesulfonic electrolyte to develop high-performance rechargeable zinc batteries.

  11. Power generation using spinel manganese-cobalt oxide as a cathode catalyst for microbial fuel cell applications.

    PubMed

    Mahmoud, Mohamed; Gad-Allah, Tarek A; El-Khatib, K M; El-Gohary, Fatma

    2011-11-01

    This study focused on the use of spinel manganese-cobalt (Mn-Co) oxide, prepared by a solid state reaction, as a cathode catalyst to replace platinum in microbial fuel cells (MFCs) applications. Spinel Mn-Co oxides, with an Mn/Co atomic ratios of 0.5, 1, and 2, were prepared and examined in an air cathode MFCs which was fed with a molasses-laden synthetic wastewater and operated in batch mode. Among the three Mn-Co oxide cathodes and after 300 h of operation, the Mn-Co oxide catalyst with Mn/Co atomic ratio of 2 (MnCo-2) exhibited the highest power generation 113 mW/m2 at cell potential of 279 mV, which were lower than those for the Pt catalyst (148 mW/m2 and 325 mV, respectively). This study indicated that using spinel Mn-Co oxide to replace platinum as a cathodic catalyst enhances power generation, increases contaminant removal, and substantially reduces the cost of MFCs.

  12. Critical parameters governing energy density of Li-storage cathode materials unraveled by confirmatory factor analysis

    NASA Astrophysics Data System (ADS)

    Sohn, Kee-Sun; Han, Su Cheol; Park, Woon Bae; Pyo, Myoungho

    2016-03-01

    Despite extensive effort during the past few decades, a comprehensive understanding of the key variables governing the electrochemical properties of cathode materials in Li-ion batteries is still far from complete. To elucidate the critical parameters affecting energy density (ED) and capacity (Q) retention in layer and spinel cathodes, we data-mine the existing experimental data via confirmatory factor analysis (CFA) based on a structural equation model (SEM), which is a proven, versatile tool in understanding complex problems in the social science. The data sets are composed of 18 and 15 parameters extracted from 38 layer and 33 spinel compounds, respectively. CFA reveals the irrelevance of Q retention to all the parameters we adopt, but it also reveals the sensitive variations of ED with specific parameters. We validate the usefulness of CFA in material science and pinpointed critical parameters for high-ED cathodes, hoping to suggest a new insight in materials design.

  13. Prospects for Spinel-Stabilized, High-Capacity Lithium-Ion Battery Cathodes

    SciTech Connect

    Croy, Jason R.; Park, Joong Sun; Shin, YoungHo; Yonemoto, Bryan T.; Balasubramanian, Mahalingam; Long, Brandon R.; Ren, Yang; Thackeray, Michael M.

    2016-12-01

    Herein we report early results on efforts to optimize the electrochemical performance of a cathode composed of a lithium- and manganese-rich “layered-layered-spinel” material for lithium-ion battery applications. Pre-pilot scale synthesis leads to improved particle properties compared with lab-scale efforts, resulting in high capacities (≳200 mAh/g) and good energy densities (>700 Wh/kg) in tests with lithium-ion cells. Subsequent surface modifications give further improvements in rate capabilities and high-voltage stability. These results bode well for advances in the performance of this class of lithium- and manganese-rich cathode materials.

  14. Prospects for spinel-stabilized, high-capacity lithium-ion battery cathodes

    DOE PAGES

    Croy, Jason R.; Park, Joong Sun; Shin, Youngho; ...

    2016-10-13

    Herein we report early results on efforts to optimize the electrochemical performance of a cathode composed of a lithium- and manganese-rich “layered-layered-spinel” material for lithium-ion battery applications. Pre-pilot scale synthesis leads to improved particle properties compared with lab-scale efforts, resulting in high capacities (≳200 mAh/g) and good energy densities (>700 Wh/kg) in tests with lithium-ion cells. Subsequent surface modifications give further improvements in rate capabilities and high-voltage stability. These results bode well for advances in the performance of this class of lithium- and manganese-rich cathode materials.

  15. M{sup 3+}-modified LiMn{sub 2}O{sub 4} spinel intercalation cathodes. 1: Admetal effects on morphology and electrochemical performance

    SciTech Connect

    Robertson, A.D.; Lu, S.H.; Averill, W.F.; Howard, W.F. Jr.

    1997-10-01

    Low levels of trivalent cations were utilized to stabilize LiMn{sub 2}O{sub 4} spinel cathode materials against capacity decline during electrochemical cycling. Of the several single-phase products obtained, only those with Cr{sup 3+} and Ga{sup 3+} prevented capacity fade, and only LiCr{sub 0.02}Mn{sub 1.98}O{sub 4} exhibited acceptable initial reversible capacity. The external particle morphology was unchanged by the preparation or the admetal, and the internal structures were all converted to cong tou (onion) configurations during product synthesis. Grain size played a surprising role in cathode performance <25 {micro}m material had at least 10% lower capacity than larger or as-prepared Cr-doped LiMn{sub 2}O{sub 4}.

  16. Pyrite cathode material for a thermal battery

    NASA Astrophysics Data System (ADS)

    Pemsler, J. P.; Litchfield, J. K.

    1991-02-01

    The present invention relates in general to a synthetic cathode material for a molten salt battery and, more particularly, to a process of providing and using synthetic pyrite for use as a cathode in a thermal battery. These batteries, which have been successfully used in a number of military applications, include iron disulfide cathode material obtained as benefacted or from natural occurring pyrite deposits, or as a byproduct of flotation concentrate from the processing of base or noble metal ores.

  17. High-Capacity, High-Voltage Composite Oxide Cathode Materials

    NASA Technical Reports Server (NTRS)

    Hagh, Nader M.

    2015-01-01

    This SBIR project integrates theoretical and experimental work to enable a new generation of high-capacity, high-voltage cathode materials that will lead to high-performance, robust energy storage systems. At low operating temperatures, commercially available electrode materials for lithium-ion (Li-ion) batteries do not meet energy and power requirements for NASA's planned exploration activities. NEI Corporation, in partnership with the University of California, San Diego, has developed layered composite cathode materials that increase power and energy densities at temperatures as low as 0 degC and considerably reduce the overall volume and weight of battery packs. In Phase I of the project, through innovations in the structure and morphology of composite electrode particles, the partners successfully demonstrated an energy density exceeding 1,000 Wh/kg at 4 V at room temperature. In Phase II, the team enhanced the kinetics of Li-ion transport and electronic conductivity at 0 degC. An important feature of the composite cathode is that it has at least two components that are structurally integrated. The layered material is electrochemically inactive; however, upon structural integration with a spinel material, the layered material can be electrochemically activated and deliver a large amount of energy with stable cycling.

  18. Ionic modeling of lithium manganese spinel materials for use in rechargeable batteries

    SciTech Connect

    Cygan, R.T.; Westrich, H.R.; Doughty, D.H.

    1995-12-31

    In order to understand and evaluate materials for use in lithium ion rechargeable battery electrodes, the authors have modeled the crystal structures of various manganese oxide and lithium manganese oxide compounds. They have modeled the MnO{sub 2} polymorphs and several spinels with intermediate compositions based on the amount of lithium inserted into the tetrahedral site. Three-dimensional representations of the structures provide a basis for identifying site occupancies, coordinations, manganese valence, order-disorder, and potentially new dopants for enhanced cathode behavior. X-ray diffraction simulations of the crystal structures provide good agreement with observed patterns for synthesized samples. Ionic modeling of these materials consists of an energy minimization approach using Coulombic, repulsive, and van der Waals interactions. Modeling using electronic polarizability (shell model) allows a systematic analysis of changes in lattice energy, cell volume, and the relative stability of doped structures using ions such as aluminum, titanium, nickel, and cobalt.

  19. Cyclic oxidation of Mn-Co spinel coated SUS 430 alloy in the cathodic atmosphere of solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Hua, Bin; Pu, Jian; Gong, Wei; Zhang, Jianfu; Lu, Fengshuang; Jian, Li

    In order to improve oxidation resistance and long-term stability of the metallic interconnects and prevent the cathode of solid oxide fuel cells (SOFCs) from Cr-poisoning, an effective, relatively dense and well adherent Mn-Co spinel protection coating with a nominal composition of MnCo 2O 4 is applied onto the surfaces of the SUS 430 ferritic stainless steel by a cost-effective sol-gel process. The long-term thermally cyclic oxidation kinetics and oxide scale structures as well as the composition of the coated SUS 430 alloy are investigated. The Mn-Co spinel protection layer demonstrates an excellent structural and thermomechanical stability, and effectively acts as a mass barrier to the outward diffusion of cations, especially Cr, and a lowered parabolic rate constant of k p = 1.951 × 10 -15 g 2 cm -4 s -1 is obtained.

  20. Cells having cathodes containing polycarbon disulfide materials

    DOEpatents

    Okamoto, Yoshi; Skotheim, Terje A.; Lee, Hung S.

    1995-08-15

    The present invention relates to an electric current producing cell which contains an anode, a cathode having as a cathode-active material one or more carbon-sulfur compounds of the formula (CS.sub.x).sub.n, in which x takes values from 1.2 to 2.3 and n is greater or equal to 2, and where the redox process does not involve polymerization and de-polymerization by forming and breaking S--S bonds in the polymer backbone. The cell also contains an electrolyte which is chemically inert with respect to the anode and the cathode.

  1. Cells having cathodes containing polycarbon disulfide materials

    DOEpatents

    Okamoto, Y.; Skotheim, T.A.; Lee, H.S.

    1995-08-15

    The present invention relates to an electric current producing cell which contains an anode, a cathode having as a cathode-active material one or more carbon-sulfur compounds of the formula (CS{sub x}){sub n}, in which x takes values from 1.2 to 2.3 and n is greater or equal to 2, and where the redox process does not involve polymerization and de-polymerization by forming and breaking S--S bonds in the polymer backbone. The cell also contains an electrolyte which is chemically inert with respect to the anode and the cathode. 5 figs.

  2. Cr{sup 3+} modified LiMn{sub 2}O{sub 4} spinel intercalation cathodes through oxalic acid assisted sol-gel method for lithium rechargeable batteries

    SciTech Connect

    Thirunakaran, R. . E-mail: rthirunakaran@yahoo.com; Kim, Ki-Tae; Kang, Yong-Mook; Young-Lee, Jai

    2005-01-04

    To improve the cycle performance of eco-friendly and cost-effective spinel LiMn{sub 2}O{sub 4} as the cathode of 4 V class Li secondary batteries, the spinel phase LiCr{sub x}Mn{sub 2-x}O{sub 4} (x = 0.01-0.20) was synthesized by soft chemistry method using oxalic acid as chelating agent. The present technique results in better homogeneity, good surface morphology, shorter heat treatment time, sub-micron sized particles, good agglomeration and better crystallinity. Electrochemical studies were monitored in the potential range of 3-4.5 V. The present paper reveals that chromium substituted manganese spinel improves the structural stability of the parent material.

  3. Interfacial phenomena on selected cathode materials

    SciTech Connect

    Kostecki, Robert; Matsuo, Yoshiaki; McLarnon, Frank

    2001-06-22

    We have carried out a series of surface studies of selected cathode materials. Instrumental techniques such as Raman microscopy, surface enhanced Raman spectroscopy (SERS), and atomic force microscopy were used to investigate the cathode surfaces. The goal of this study was to identify detrimental processes which occur at the electrode/electrolyte interface and can lead to electrode degradation and failure during cycling and/or storage at elevated temperatures.

  4. Capacity improvement by deficit of transition metals in inverse spinel LiNi1/3Co1/3Mn1/3VO4 cathodes

    NASA Astrophysics Data System (ADS)

    Kitajou, Ayuko; Yoshida, Jun; Nakanishi, Shinji; Matsuda, Yasuaki; Kanno, Ryoji; Okajima, Toshihiro; Okada, Shigeto

    2016-01-01

    Although inverse spinel materials have attracted attention because of their unusually high voltage characteristics, their rechargeable capacities are generally less than 50 mAh g-1, as a result of the coexistence of Li and transition metal ions at 16d octahedral sites. This work attempted to improve cathode functioning by optimizing the quantities of Li and transition metal ions residing at the 16d sites of LiNi1/3Co1/3Mn1/3VO4. The rechargeable capacity of the LiNi0.28Co0.28Mn0.26V0.80O4 synthesized in the present study was found to be above 120 mAh g-1, representing the largest capacity reported to date for an inverse spinel material. The results of in-situ XANES analysis demonstrated that the charge-discharge reactions of LiNi1/3Co1/3Mn1/3VO4 corresponds to the Mn2+/Mn4+ and Co2+/Co3+ redox couples, mainly.

  5. NANOWIRE CATHODE MATERIAL FOR LITHIUM-ION BATTERIES

    SciTech Connect

    John Olson, PhD

    2004-07-21

    This project involved the synthesis of nanowire ã-MnO2 and characterization as cathode material for high-power lithium-ion batteries for EV and HEV applications. The nanowire synthesis involved the edge site decoration nanowire synthesis developed by Dr. Reginald Penner at UC Irvine (a key collaborator in this project). Figure 1 is an SEM image showing ã-MnO2 nanowires electrodeposited on highly oriented pyrolytic graphite (HOPG) electrodes. This technique is unique to other nanowire template synthesis techniques in that it produces long (>500 um) nanowires which could reduce or eliminate the need for conductive additives due to intertwining of fibers. Nanowire cathode for lithium-ion batteries with surface areas 100 times greater than conventional materials can enable higher power batteries for electric vehicles (EVs) and hybrid electric vehicles (HEVs). The synthesis of the ã-MnO2 nanowires was successfully achieved. However, it was not found possible to co-intercalate lithium directly in the nanowire synthesis. Based on input from proposal reviewers, the scope of the project was altered to attempt the conversion into spinel LiMn2O4 nanowire cathode material by solid state reaction of the ã-MnO2 nanowires with LiNO3 at elevated temperatures. Attempts to perform the conversion on the graphite template were unsuccessful due to degradation of the graphite apparently caused by oxidative attack by LiNO3. Emphasis then shifted to quantitative removal of the nanowires from the graphite, followed by the solid state reaction. Attempts to quantitatively remove the nanowires by several techniques were unsatisfactory due to co-removal of excess graphite or poor harvesting of nanowires. Intercalation of lithium into ã-MnO2 electrodeposited onto graphite was demonstrated, showing a partial demonstration of the ã-MnO2 material as a lithium-ion battery cathode material. Assuming the issues of nanowires removal can be solved, the technique does offer potential for creating

  6. 2013 Estorm - Invited Paper - Cathode Materials Review

    SciTech Connect

    Daniel, Claus; Mohanty, Debasish; Li, Jianlin; Wood III, David L

    2014-01-01

    The electrochemical potential of cathode materials defines the positive side of the terminal voltage of a battery. Traditionally, cathode materials are the energy-limiting or voltage-limiting electrode. One of the first electrochemical batteries, the voltaic pile invented by Alessandro Volta in 1800 (Phil. Trans. Roy. Soc. 90, 403 431) had a copper-zinc galvanic element with a terminal voltage of 0.76 V. Since then, the research community has increased capacity and voltage for primary (nonrechargeable) batteries and round-trip efficiency for secondary (rechargeable) batteries. Successful secondary batteries have been the lead acid with a lead oxide cathode and a terminal voltage of 2.1 V and later the NiCd with a nickel(III) oxide hydroxide cathode and a 1.2 V terminal voltage. The relatively low voltage of those aqueous systems and the low round-trip efficiency due to activation energies in the conversion reactions limited their use. In 1976, Wittingham (J. Electrochem. Soc., 123, 315) and Besenhard (J Power Sources 1(3), 267) finally enabled highly reversible redox reactions by intercalation of lithium ions instead of by chemical conversion. In 1980, Goodenough and Mizushima (Mater. Res. Bull. 15, 783 789) demonstrated a high-energy and high-power LiCoO2 cathode, allowing for an increase of terminal voltage far beyond 3 V. Over the past four decades, the international research community has further developed cathode materials of many varieties. Current state-of-the-art cathodes demonstrate voltages beyond any known electrolyte stability window, bringing electrolyte research once again to the forefront of battery research.

  7. Improved cathode materials for microbial electrosynthesis

    SciTech Connect

    Zhang, T; Nie, HR; Bain, TS; Lu, HY; Cui, MM; Snoeyenbos-West, OL; Franks, AE; Nevin, KP; Russell, TP; Lovley, DR

    2013-01-01

    Microbial electrosynthesis is a promising strategy for the microbial conversion of carbon dioxide to transportation fuels and other organic commodities, but optimization of this process is required for commercialization. Cathodes which enhance electrode-microbe electron transfer might improve rates of product formation. To evaluate this possibility, biofilms of Sporomusa ovata, which are effective in acetate electrosynthesis, were grown on a range of cathode materials and acetate production was monitored over time. Modifications of carbon cloth that resulted in a positive-charge enhanced microbial electrosynthesis. Functionalization with chitosan or cyanuric chloride increased acetate production rates 6-7 fold and modification with 3-aminopropyltriethoxysilane gave rates 3-fold higher than untreated controls. A 3-fold increase in electrosynthesis over untreated carbon cloth cathodes was also achieved with polyaniline cathodes. However, not all strategies to provide positively charged surfaces were successful, as treatment of carbon cloth with melamine or ammonia gas did not stimulate acetate electrosynthesis. Treating carbon cloth with metal, in particular gold, palladium, or nickel nanoparticles, also promoted electrosynthesis, yielding electrosynthesis rates that were 6-,4.7- or 4.5-fold faster than the untreated control, respectively. Cathodes comprised of cotton or polyester fabric treated with carbon nanotubes yielded cathodes that supported acetate electrosynthesis rates that were similar to 3-fold higher than carbon cloth controls. Recovery of electrons consumed in acetate was similar to 80% for all materials. The results demonstrate that one approach to increase rates of carbon dioxide reduction in microbial electrosynthesis is to modify cathode surfaces to improve microbe-electrode interactions.

  8. LiMn{sub 2-x}Cu{sub x}O{sub 4} spinels (0.1 {le} x {le} 0.5) - a new class of 5 V cathode materials for Li batteries : I. electrochemical, structural and spectroscopic studies.

    SciTech Connect

    Ein-Eli, Y.

    1998-10-05

    A series of electroactive spinel compounds, LiMn{sub 2{minus}x}Cu{sub x}O{sub 4} (0.1 {le} x {le} 0.5) has been studied by crystallographic, spectroscopic and electrochemical methods and by electron-microscopy. These LiMn{sub 2{minus}x}Cu{sub x}O{sub 4} spinels are nearly identical in structure to cubic LiMn{sub 2}O{sub 4} and successfully undergo reversible Li intercalation. The electrochemical data show a remarkable reversible electrochemical process at 4.9 V which is attributed to the oxidation of Cu{sup 2+} to Cu{sub 3+}. The inclusion of Cu in the spinel structure enhances the electrochemical stability of these materials upon cycling. The initial capacity of LiMn{sub 2{minus}x}Cu{sub x}O{sub 4} spinels decreases with increasing x from 130mAh/g in LiMn{sub 2}O{sub 4} (x=0) to 70 mAh/g in ''LiMn{sub 1.5}Cu{sub 0.5}O{sub 4}'' (x=0.5). The data also show slight shifts to higher voltage for the delithiation reaction that normally occurs at 4.1 V in standard Li{sub 1{minus}x}Mn{sub 2}O{sub 4} electrodes (1 {ge} x {ge} 0) corresponding to the oxidation of Mn{sup 3+} to Mn{sup 4+}. Although the powder X-ray diffraction pattern of ''LiMn{sub 1.5}Cu{sub 0.5}O{sub 4}'' shows a single-phase spinel product, neutron diffraction data show a small, but significant quantity of an impurity phase, the composition and structure of which could not be identified. X-ray absorption spectroscopy was used to gather information about the oxidation states of the manganese and copper ions. The composition of the spinel component in the LiMn{sub 1.5}Cu{sub 0.5}O{sub 4} was determined from X-ray diffraction and XANES data to be Li{sub 1.01}Mn{sub 1.67}Cu{sub 0.32}O{sub 4} suggesting, to a best approximation, that the impurity in the sample was a lithium-copper-oxide phase. The substitution of manganese by copper enhances the reactivity of the spinel structure towards hydrogen; the compounds are more easily reduced at moderate temperature ({approximately} 200 C) than LiMn{sub 2}O{sub 4}.

  9. High rate capability caused by surface cubic spinels in Li-rich layer-structured cathodes for Li-ion batteries

    PubMed Central

    Song, Bohang; Liu, Hongwei; Liu, Zongwen; Xiao, Pengfei; Lai, Man On; Lu, Li

    2013-01-01

    Modified Li-rich layered cathode Li(Li0.2Mn0.54Ni0.13Co0.13)O2 has been synthesized by a simple strategy of using surface treatment with various amounts (0–30 wt.%) of Super P (carbon black). Based on detailed characterizations from X-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS), it is suggested that the phase transformation from Li2MnO3-type of structure to spinel-like phase take place at the surface regions of particles during post annealing process at 350°C, leading to increase in both first coulombic efficiency and rate capability, from 78% and 100 mAh·g−1 (charge capacity at 2500 mA·g−1) of the pristine material to 93.4% and 200 mAh·g−1. The evidences of spinel formation and the reasons for electrochemical enhancement are systematically investigated. PMID:24172795

  10. High performance cobalt-free Cu1.4Mn1.6O4 spinel oxide as an intermediate temperature solid oxide fuel cell cathode

    NASA Astrophysics Data System (ADS)

    Zhen, Shuying; Sun, Wang; Li, Peiqian; Tang, Guangze; Rooney, David; Sun, Kening; Ma, Xinxin

    2016-05-01

    In this work Cu1.4Mn1.6O4 (CMO) spinel oxide is prepared and evaluated as a novel cobalt-free cathode for intermediate temperature solid oxide fuel cells (IT-SOFCs). Single phase CMO powder with cubic structure is identified using XRD. XPS results confirm that mixed Cu+/Cu2+ and Mn3+/Mn4+ couples exist in the CMO sample, and a maximum conductivity of 78 S cm-1 is achieved at 800 °C. Meanwhile, CMO oxide shows good thermal and chemical compatibility with a 10 mol% Sc2O3 stabilized ZrO2 (ScSZ) electrolyte material. Impedance spectroscopy measurements reveals that CMO exhibits a low polarization resistance of 0.143 Ω cm2 at 800 °C. Furthermore, a Ni-ScSZ/ScSZ/CMO single cell demonstrates a maximum power density of 1076 mW cm-2 at 800 °C under H2 (3% H2O) as the fuel and ambient air as the oxidant. These results indicate that Cu1.4Mn1.6O4 is a superior and promising cathode material for IT-SOFCs.

  11. Deep Discharge Characteristics of LiMn2O4-dCld Cathode Material

    DTIC Science & Technology

    2014-06-12

    A stable chlorine -modified lithium manganese based AB2O4 spinel material was formulated, fabricated, and characterized as a positive electrode...region for the Li//LixMn2O4-yClz electrochemical couple is 0.05 < x < 1.75. The chlorine -modified LixMn2O4 cathode material allows for over-discharge...protection. Reversibility in the material is maintained after cell potential excursions less than 2.0 volts are performed. When the chlorine

  12. NUMERICAL MODELING OF CATHODE CONTACT MATERIAL DENSIFICATION

    SciTech Connect

    Koeppel, Brian J.; Liu, Wenning N.; Stephens, Elizabeth V.; Khaleel, Mohammad A.

    2011-11-01

    Numerical modeling was used to simulate the constrained sintering process of the cathode contact layer during assembly of solid oxide fuel cells (SOFCs). A finite element model based on the continuum theory for sintering of porous bodies was developed and used to investigate candidate low-temperature cathode contact materials. Constitutive parameters for various contact materials under investigation were estimated from dilatometry screening tests, and the influence of processing time, processing temperature, initial grain size, and applied compressive stress on the free sintering response was predicted for selected candidate materials. The densification behavior and generated stresses within a 5-cell planar SOFC stack during sintering, high temperature operation, and room temperature shutdown were predicted. Insufficient constrained densification was observed in the stack at the proposed heat treatment, but beneficial effects of reduced grain size, compressive stack preload, and reduced thermal expansion coefficient on the contact layer densification and stresses were observed.

  13. Improved Lithium-Intercalation Cathode Material.

    DTIC Science & Technology

    1984-11-01

    D-A149 39 IMPROVED LITHIUM-INTERCALATION CATHODE MATERIAL(U) ECO / UNCLASSIFIED F/O 7/4 NL M..’. ..... ~~~~. . .--...-. ~ .. . 7 -7 1111& 1&.O8 L& L...program, ECO will evaluate cycle life, . lithium diffusion rate, and self-discharge rates of the five TAAs. Sincerely, Fraser Walsh FW:nck | D TAB I t

  14. The loss of material from the cathode of metal arcs

    NASA Technical Reports Server (NTRS)

    Seeliger, R.; Wulfhekel, H.

    1985-01-01

    A study was made of the effect of arc length, cathode thickness, current strength, gas pressure and the chemical nature of the cathode material and filling gases upon the material loss from Cu, Fe, and Ag cathodes in arcs. The results show that the analysis of the phenomenon is complex and the energy balance is difficult to formulate.

  15. Review on MIEC Cathode Materials for Solid Oxide Fuel Cells

    NASA Astrophysics Data System (ADS)

    Burnwal, Suman Kumar; Bharadwaj, S.; Kistaiah, P.

    2016-11-01

    The cathode is one of the most important components of solid oxide fuel cells (SOFCs). The reduction of oxygen at the cathode (traditional cathodes like LSM, LSGM, etc.) is the slow step in the cell reaction at intermediate temperature (600-800∘C) which is one of the key obstacles to the development of SOFCs. The mixed ionic and electronic conducting cathode (MIEC) like LSCF, BSCF, etc., has recently been proposed as a promising cathode material for SOFC due to the improvement of the kinetic of the cathode reaction. The MIEC materials provide not only the electrons for the reduction of oxygen, but also the ionic conduction required to ensure the transport of the formed oxygen ions and thereby improves the overall electrochemical performance of SOFC system. The characteristics of MIEC cathode materials and its comparison with other traditional cathode materials is studied and presented in the paper.

  16. Structural and Chemical Evolution of Li- and Mn-rich Layered Cathode Material

    SciTech Connect

    Zheng, Jianming; Xu, Pinghong; Gu, Meng; Xiao, Jie; Browning, Nigel D.; Yan, Pengfei; Wang, Chong M.; Zhang, Jiguang

    2015-02-24

    Lithium (Li)- and manganese-rich (LMR) layered-structure materials are very promising cathodes for high energy density lithium-ion batteries. However, their voltage fading mechanism and its relationships with fundamental structural changes are far from being sufficiently understood. Here we report the detailed phase transformation pathway in the LMR cathode (Li[Li0.2Ni0.2Mn0.6]O2) during cycling for the samples prepared by hydro-thermal assistant method. It is found the transformation pathway of LMR cathode is closely correlated to its initial structure and preparation conditions. The results reveal that LMR cathode prepared by HA approach experiences a phase transformation from the layered structure to a LT-LiCoO2 type defect spinel-like structure (Fd-3m space group) and then to a disordered rock-salt structure (Fm-3m space group). The voltage fade can be well correlated with the Li ion insertion into octahedral sites, rather than tetrahedral sites, in both defect spinel-like structure and disordered rock-salt structure. The reversible Li insertion/removal into/from the disordered rock-salt structure is ascribed to the Li excess environment that can satisfy the Li percolating in the disordered rock-salt structure despite the increased kinetic barrier. Meanwhile, because of the presence of a great amount of oxygen vacancies, a significant decrease of Mn valence is detected in the cycled particle, which is below that anticipated for a potentially damaging Jahn-Teller distortion (+3.5). Clarification of the phase transformation pathway, cation redistribution, oxygen vacancy and Mn valence change undoubtedly provides insights into a profound understanding on the voltage fade, and capacity degradation of LMR cathode. The results also inspire us to further enhance the reversibility of LMR cathode via improving its surface structural stability.

  17. Organic Cathode Materials for Rechargeable Batteries

    SciTech Connect

    Cao, Ruiguo; Qian, Jiangfeng; Zhang, Jiguang; Xu, Wu

    2015-06-28

    This chapter will primarily focus on the advances made in recent years and specify the development of organic electrode materials for their applications in rechargeable lithium batteries, sodium batteries and redox flow batteries. Four various organic cathode materials, including conjugated carbonyl compounds, conducting polymers, organosulfides and free radical polymers, are introduced in terms of their electrochemical performances in these three battery systems. Fundamental issues related to the synthesis-structure-activity correlations, involved work principles in energy storage systems, and capacity fading mechanisms are also discussed.

  18. Stable, high voltage Li0.85Ni0.46Cu0.1Mn1.49O4 spinel cathode in a lithium-ion battery using a conversion-type CuO anode.

    PubMed

    Verrelli, Roberta; Scrosati, Bruno; Sun, Yang-Kook; Hassoun, Jusef

    2014-04-09

    We report in this work a copper-doped Li0.85Ni0.46Cu0.1Mn1.49O4 spinel-structured compound prepared by an easy, two-steps coprecipitation and solid state process and used in a lithium-ion battery in combination with a CuO-based anode. We show that the spinel-type cathode adopts unique morphology, characterized by well-developed, crystalline and aggregated microparticles, that considerably reduces the occurrence of side reactions. This cathode material can operate in a lithium cell at voltages as high as 5.3 V without sign of electrolyte decomposition, delivering a capacity of about 100 mA h g(-1) with high retention and high Coulombic efficiency over prolonged cycling. The combination of the Li0.85Ni0.46Cu0.1Mn1.49O4 cathode with a conversion-type, CuO-MCMB anode results in a new type of lithium ion battery characterized by a voltage value of 3.4 V, a stable capacity of 100 mA h g(-1) and a high Coulombic efficiency (exceeding 95%). Expected low cost, safety, and environmental compatibility are additional advantages of the lithium-ion cell reported here.

  19. Oxide diffusion in innovative SOFC cathode materials.

    PubMed

    Hu, Y; Thoréton, V; Pirovano, C; Capoen, E; Bogicevic, C; Nuns, N; Mamede, A-S; Dezanneau, G; Vannier, R N

    2014-01-01

    Oxide diffusion was studied in two innovative SOFC cathode materials, Ba(2)Co(9)O(14) and Ca(3)Co(4)O(9)+δ derivatives. Although oxygen diffusion was confirmed in the promising material Ba(2)Co(9)O(14), it was not possible to derive accurate transport parameters because of an oxidation process at the sample surface which has still to be clarified. In contrast, oxygen diffusion in the well-known Ca(3)Co(4)O(9)+δ thermoelectric material was improved when calcium was partly substituted with strontium, likely due to an increase of the volume of the rock salt layers in which the conduction process takes place. Although the diffusion coefficient remains low, interestingly, fast kinetics towards the oxygen molecule dissociation reaction were shown with surface exchange coefficients higher than those reported for the best cathode materials in the field. They increased with the strontium content; the Sr atoms potentially play a key role in the mechanism of oxygen molecule dissociation at the solid surface.

  20. Nanostructured cathode materials for rechargeable lithium batteries

    NASA Astrophysics Data System (ADS)

    Myung, Seung-Taek; Amine, Khalil; Sun, Yang-Kook

    2015-06-01

    The prospect of drastic climate change and the ceaseless fluctuation of fossil fuel prices provide motivation to reduce the use of fossil fuels and to find new energy conversion and storage systems that are able to limit carbon dioxide generation. Among known systems, lithium-ion batteries are recognized as the most appropriate energy storage system because of their high energy density and thus space saving in applications. Introduction of nanotechnology to electrode material is beneficial to improve the resulting electrode performances such as capacity, its retention, and rate capability. The nanostructure is highly available not only when used alone but also is more highlighted when harmonized in forms of core-shell structure and composites with carbon nanotubes, graphene or reduced graphene oxides. This review covers syntheses and electrochemical properties of nanoscale, nanosized, and nanostructured cathode materials for rechargeable lithium batteries.

  1. Properties of cathode materials in alkaline cells

    NASA Astrophysics Data System (ADS)

    Salkind, A. J.; McBreen, J.; Freeman, R.; Parkhurst, W. A.

    1984-04-01

    Conventional and new cathode materials in primary and secondary alkaline cells were investigated for stability, structure, electrochemical reversibility and efficiency. Included were various forms of AgO for reserve type silver zinc batteries, a new material - AgNiO2 and several nickel electrodes for nickel cadmium and nickel hydrogen cells for aerospace applications. A comparative study was made of the stability of electroformed and chemically prepared AgO. Stability was correlated with impurities. After the first discharge AgNiO2 can be recharged to the monovalent level. The discharge product is predominantly silver. Plastic bonded nickel electrodes display a second plateau on discharge. Additions of Co(OH)2 largely eliminate this.

  2. The performance of spinel bulk-like oxygen-deficient CoGa2O4 as an air-cathode catalyst in microbial fuel cell

    NASA Astrophysics Data System (ADS)

    Liu, Di; Mo, Xiaoping; Li, Kexun; Liu, Yi; Wang, Junjie; Yang, Tingting

    2017-08-01

    Nano spinel bulk-like CoGa2O4 prepared via a facile hydrothermal method is used as a high efficient electrochemical catalyst in activated carbon (AC) air-cathode microbial fuel cell (MFC). The maximum power density of the modified MFC is 1911 ± 49 mW m-2, 147% higher than the MFC of untreated AC cathode. Transmission electron microscope (TEM) and X-ray diffraction (XRD) exhibit the morphology and crystal structure of CoGa2O4. Rotating disk electrode (RDE) confirms the four-electron pathway at the cathode during the oxygen reduction reaction (ORR). Thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) illustrate that the high rate oxygen vacancy exist in the CoGa2O4. The oxygen vacancy of CoGa2O4 plays an important role in catalytic activity. In a word, the prepared nano spinel bulk-like CoGa2O4 provides an alternative to the costly Pt in air-cathode for power output.

  3. The positive roles of integrated layered-spinel structures combined with nanocoating in low-cost Li-rich cathode Li[Li₀.₂Fe₀.₁Ni₀.₁₅Mn₀.₅₅]O₂ for lithium-ion batteries.

    PubMed

    Zhao, Taolin; Chen, Shi; Chen, Renjie; Li, Li; Zhang, Xiaoxiao; Xie, Man; Wu, Feng

    2014-12-10

    As the most promising cathodes of lithium-ion batteries, lithium-rich manganese-based layered oxides with high capacity suffer from poor cycle stability, poor rate capability, and fast voltage fading. Here we introduced AlF3 into the surface of layered lithium-rich cathode (Li[Li0.2Fe0.1Ni0.15Mn0.55]O2) as an artificial protective layer as well as an inducer of integrated layered-spinel structures to achieve both low cost and high capacity. The reduced irreversible capacity loss, improved cycling stability, and superior high-rate capability were ascribed to the combination of AlF3 nanocoating and the unique structures as well as the low charge transfer resistance. Besides, the intractable issue, fast voltage fading of the layered lithium-rich cathode was also alleviated. Such materials with both low cost and high capacity are considered to be promising candidate cathodes to achieve lithium-ion batteries with high energy and high power.

  4. Alumina-magnesia spinel for refractories synthesized from natural raw materials

    SciTech Connect

    Moore, R.E.; Monton, B.S. . Ceramic engineering Dept.)

    1993-03-01

    Spinel is proving to be a high quality refractory for specific applications. Synthesis of spinel in this study involved using either diaspore or bauxite in its raw form. The diaspore was obtained from a central Missouri deposit and the bauxites were obtained from China and Guyana. Diaspore and bauxite source materials need to have a low alkali content and a high alumina content in order to produce a stable refractory spinel. The raw materials are ground below 45 microns and combined with hardbured magnesia, also below 45 microns, in appropriate compositions to yield spinel. Dry mixing was used to obtain homogeneous mixtures of the raw materials and magnesia. Compacts of different compositions were fired at 1,600 C prior to the creep testing. Creep analysis was done to determine the load bearing capabilities and refractoriness. X-ray diffraction and microstructural analysis, including point count analysis and cathodoluminescence, was carried out to determine completeness of the reactions and morphologies of the reaction products.

  5. A Novel Cathode Material for Cathodic Dehalogenation of 1,1-Dibromo Cyclopropane Derivatives.

    PubMed

    Gütz, Christoph; Selt, Maximilian; Bänziger, Markus; Bucher, Christoph; Römelt, Christina; Hecken, Nadine; Gallou, Fabrice; Galvão, Tomás R; Waldvogel, Siegfried R

    2015-09-28

    Leaded bronze turned out to be an excellent cathode material for the dehalogenation reaction of cyclopropanes without affecting the strained molecular entity. With this particular alloy, beneficial properties of lead cathodes are conserved, whereas the corrosion of cathode is efficiently suppressed. The solvent in the electrolyte determines whether a complete debromination reaction is achieved or if the process can be selectively stopped at the monobromo cyclopropane intermediate. The electroorganic conversion tolerates a variety of functional groups and can be conducted at rather complex substrates like cyclosporine A. This approach allows the sustainable preparation of cyclopropane derivatives.

  6. Filed emission cathodes for electrodynamic tethers: identifying compatible cathode materials

    NASA Technical Reports Server (NTRS)

    Marrese, C.; Polk, J.; Mackie, B.; Quinlan, M.; Koel, B.

    2002-01-01

    Several material combinations were considered as candidates for the electrodynamic tether application in the investigation discussed in this paper. Critical characteristics like work function, resistance, sputter yield and sensitivity to oxidizing environments were considered. The material investigation included, ZrC/Mo, Mo, MgPt, Pt, NbC/Nb, NbNi/Nb, Nb, RuTa/Ta, Ru/Ta and Ta. The results of the measurements suggest that NbC/Nb, NbNi/Nb, and MgPt are the most promising candidates.

  7. Layered Lithium-Rich Oxide Nanoparticles Doped with Spinel Phase: Acidic Sucrose-Assistant Synthesis and Excellent Performance as Cathode of Lithium Ion Battery.

    PubMed

    Chen, Min; Chen, Dongrui; Liao, Youhao; Zhong, Xiaoxin; Li, Weishan; Zhang, Yuegang

    2016-02-01

    Nanolayered lithium-rich oxide doped with spinel phase is synthesized by acidic sucrose-assistant sol-gel combustion and evaluated as the cathode of a high-energy-density lithium ion battery. Physical characterizations indicate that the as-synthesized oxide (LR-SN) is composed of uniform and separated nanoparticles of about 200 nm, which are doped with about 7% spinel phase, compared to the large aggregated ones of the product (LR) synthesized under the same condition but without any assistance. Charge/discharge demonstrates that LR-SN exhibits excellent rate capability and cyclic stability: delivering an average discharge capacity of 246 mAh g(-1) at 0.2 C (1C = 250 mA g(-1)) and earning a capacity retention of 92% after 100 cycles at 4 C in the lithium anode-based half cell, compared to the 227 mA g(-1) and the 63% of LR, respectively. Even in the graphite anode-based full cell, LR-SN still delivers a capacity of as high as 253 mAh g(-1) at 0.1 C, corresponding to a specific energy density of 801 Wh kg(-1), which are the best among those that have been reported in the literature. The separated nanoparticles of the LR-SN provide large sites for charge transfer, while the spinel phase doped in the nanoparticles facilitates lithium ion diffusion and maintains the stability of the layered structure during cycling.

  8. Chromium (V) compounds as cathode material in electrochemical power sources

    DOEpatents

    Delnick, F.M.; Guidotti, R.A.; McCarthy, D.K.

    A cathode for use in a thermal battery, comprising a chromium (V) compound. The preferred materials for this use are Ca/sub 5/(CrO/sub 4/)/sub 3/Cl, Ca/sub 5/(CrO/sub 4/)OH, and Cr/sub 2/O/sub 5/. The chromium (V) compound can be employed as a cathode material in ambient temperature batteries when blended with a suitably conductive filler, preferably carbon black.

  9. Chromium (V) compounds as cathode material in electrochemical power sources

    DOEpatents

    Delnick, Frank M.; Guidotti, Ronald A.; McCarthy, David K.

    1985-01-01

    A cathode for use in a thermal battery, comprising a chromium (V) compound. The preferred materials for this use are Ca.sub.5 (CrO.sub.4).sub.3 Cl, Ca.sub.5 (CrO.sub.4).sub.3 OH, and Cr.sub.2 O.sub.5. The chromium (V) compound can be employed as a cathode material in ambient temperature batteries when blended with a suitably conductive filler, preferably carbon black.

  10. The addition of ortho-hexagon nano spinel Co3O4 to improve the performance of activated carbon air cathode microbial fuel cell.

    PubMed

    Ge, Baochao; Li, Kexun; Fu, Zhou; Pu, Liangtao; Zhang, Xi

    2015-11-01

    Commercial Co3O4 and ortho-hexagon spinel nano-Co3O4 (OHSNC) were doped in the AC at a different percentage (5%, 10% and 15%) to enhance the performance of microbial fuel cell (MFC). The maximum power density of MFC with 10% OHSNC doped cathode was 1500±14 mW m(-2), which was 97.36% and 41.24% higher than that with the bare AC air cathode and commercial Co3O4 respectively. The electrocatalytic behavior for their better performance was discussed in detail with the help of various structural and electrochemical techniques. The OHSNC was characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM). The results showed that the improved performance owed to the enhancement of both kinetics activity and the number of electron transfer in the ORR, and the internal resistance was largely reduced. Therefore, OHSNC was proved to be an excellent cathodic catalyst in AC air cathode MFC. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Perspectives on Li and transition metal fluoride phosphates as cathode materials for a new generation of Li-ion batteries

    PubMed Central

    Antipov, Evgeny V.; Khasanova, Nellie R.; Fedotov, Stanislav S.

    2015-01-01

    To satisfy the needs of rapidly growing applications, Li-ion batteries require further significant improvements of their key properties: specific energy and power, cyclability, safety and costs. The first generation of cathode materials for Li-ion batteries based on mixed oxides with either spinel or rock-salt derivatives has already been widely commercialized, but the potential to improve the performance of these materials further is almost exhausted. Li and transition metal inorganic compounds containing different polyanions are now considered as the most promising cathode materials for the next generation of Li-ion batteries. Further advances in cathode materials are considered to lie in combining different anions [such as (XO4)n− and F−] in the anion sublattice, which is expected to enhance the specific energy and power of these materials. This review focuses on recent advances related to the new class of cathode materials for Li-ion batteries containing phosphate and fluoride anions. Special attention is given to their crystal structures and the relationships between structure and properties, which are important for their possible practical applications. PMID:25610630

  12. Perspectives on Li and transition metal fluoride phosphates as cathode materials for a new generation of Li-ion batteries.

    PubMed

    Antipov, Evgeny V; Khasanova, Nellie R; Fedotov, Stanislav S

    2015-01-01

    To satisfy the needs of rapidly growing applications, Li-ion batteries require further significant improvements of their key properties: specific energy and power, cyclability, safety and costs. The first generation of cathode materials for Li-ion batteries based on mixed oxides with either spinel or rock-salt derivatives has already been widely commercialized, but the potential to improve the performance of these materials further is almost exhausted. Li and transition metal inorganic compounds containing different polyanions are now considered as the most promising cathode materials for the next generation of Li-ion batteries. Further advances in cathode materials are considered to lie in combining different anions [such as (XO4) (n-) and F(-)] in the anion sublattice, which is expected to enhance the specific energy and power of these materials. This review focuses on recent advances related to the new class of cathode materials for Li-ion batteries containing phosphate and fluoride anions. Special attention is given to their crystal structures and the relationships between structure and properties, which are important for their possible practical applications.

  13. Compatiblitity of hydrophobic ionic liquids with high performance cathode materials for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Carnes-Mason, Ezekial Robert

    Lithium batteries are widely seen as the best choice for the future of energy storage but significant improvements are still required. One important area for improvement is searching for new cathode materials that incorporate lithium at higher capacities and voltages. This increases the energy and power available from an individual electrochemical cell, which reduces the number of cells required thereby reducing the size of a battery pack. While several high voltage cathode materials have been discovered, research has been hindered due to safety concerns with current standard electrolytes at high voltages. Ionic liquids are a new class of materials that exhibit excellent electrochemical and thermal stability as well as high ionic conductivity. These qualities make them excellent candidates to replace current battery electrolytes but difficulties in purification and the sheer number of possible chemistries have inhibited their study. In this study four hydrophobic ionic liquids based on pyrrolidinium and piperidinium cations paired with bis(trifluoromethylsulfonyl)imide anions were synthesized using bench top methods. These ionic liquids were successfully incorporated into working half-cells with LiNi1/3Mn1/3Co 1/3O2, a high capacity layered cathode and LiNi0.5Mn 1.5O4, a high voltage spinel type cathode. By comparing the behavior of the ionic liquids a clear relationship between cation size and rate capability was shown. The improved performance and safety at elevated temperatures was also demonstrated showing that ionic liquids are excellent candidates for use as battery electrolytes.

  14. Oxygen vacancies and ordering of d-levels control voltage suppression in oxide cathodes: the case of spinel LiNi0.5Mn1.5O4-δ

    SciTech Connect

    Sushko, Petr V.; Rosso, Kevin M.; Zhang, Jiguang; Liu, Jun; Sushko, Maria L.

    2013-06-19

    Spinel Li-Mn rich oxides form one of the most promising classes of high voltage cathode materials for next generation Li-ion batteries for electric vehicle applications. Our simulations for spinel LiNi0.5Mn1.5O4 (LNMO) show that neutral oxygen vacancies promote formation of Ni-rich regions, which are negatively charged with respect to the lattice. This makes the electrons associated with these vacancies to localize on Mn3+ eg states of two types: shallow states in the Ni-rich regions and deep states in the Ni-poor regions. The positive electrostatic potential produced by the oxygen vacancies and the existence of the shallow and deep Mn3+ states result in appearance of the low-voltage region at high Li content and high-voltage region at low Li content. This is consistent with characteristic changes in the voltage capacity curves observed experimentally during electrochemical cycling. We propose that doping LNMO with judiciously selected cations can help to remedy voltage suppression effects. This approach may also be used to enhance the electrochemical stability of Li-Mn rich oxides, which tend to experience continuous voltage fade.

  15. Developing Polymer Cathode Material for the Chloride Ion Battery.

    PubMed

    Zhao, Xiangyu; Zhao, Zhigang; Yang, Meng; Xia, Hui; Yu, Tingting; Shen, Xiaodong

    2017-01-25

    The chloride ion battery is an attractive rechargeable battery owing to its high theoretical energy density and sustainable components. An important challenge for research and development of chloride ion batteries lies in the innovation of the cathode materials. Here we report a nanostructured chloride ion-doped polymer, polypyrrole chloride, as a new type of potential cathode material for the chloride ion battery. The as-prepared polypyrrole chloride@carbon nanotubes (PPyCl@CNTs) cathode shows a high reversible capacity of 118 mAh g(-1) and superior cycling stability. Reversible electrochemical reactions of the PPyCl@CNTs cathode based on the redox reactions of nitrogen species and chloride ion transfer are demonstrated. Our work may guide and offer electrode design principles for accelerating the development of rechargeable batteries with anion transfer.

  16. Comprehensive Enhancement of Nanostructured Lithium-Ion Battery Cathode Materials via Conformal Graphene Dispersion.

    PubMed

    Chen, Kan-Sheng; Xu, Rui; Luu, Norman S; Secor, Ethan B; Hamamoto, Koichi; Li, Qianqian; Kim, Soo; Sangwan, Vinod K; Balla, Itamar; Guiney, Linda M; Seo, Jung-Woo T; Yu, Xiankai; Liu, Weiwei; Wu, Jinsong; Wolverton, Chris; Dravid, Vinayak P; Barnett, Scott A; Lu, Jun; Amine, Khalil; Hersam, Mark C

    2017-04-12

    Efficient energy storage systems based on lithium-ion batteries represent a critical technology across many sectors including consumer electronics, electrified transportation, and a smart grid accommodating intermittent renewable energy sources. Nanostructured electrode materials present compelling opportunities for high-performance lithium-ion batteries, but inherent problems related to the high surface area to volume ratios at the nanometer-scale have impeded their adoption for commercial applications. Here, we demonstrate a materials and processing platform that realizes high-performance nanostructured lithium manganese oxide (nano-LMO) spinel cathodes with conformal graphene coatings as a conductive additive. The resulting nanostructured composite cathodes concurrently resolve multiple problems that have plagued nanoparticle-based lithium-ion battery electrodes including low packing density, high additive content, and poor cycling stability. Moreover, this strategy enhances the intrinsic advantages of nano-LMO, resulting in extraordinary rate capability and low temperature performance. With 75% capacity retention at a 20C cycling rate at room temperature and nearly full capacity retention at -20 °C, this work advances lithium-ion battery technology into unprecedented regimes of operation.

  17. First-principles material modeling of solid-state electrolytes with the spinel structure.

    PubMed

    Mees, Maarten J; Pourtois, Geoffrey; Rosciano, Fabio; Put, Brecht; Vereecken, Philippe M; Stesmans, André

    2014-03-21

    Ionic diffusion through the novel (AlxMg1-2xLix)Al2O4 spinel electrolyte is investigated using first-principles calculations, combined with the Kinetic Monte Carlo algorithm. We observe that the ionic diffusion increases with the lithium content x. Furthermore, the structural parameters, formation enthalpies and electronic structures of (AlxMg1-2xLix)Al2O4 are calculated for various stoichiometries. The overall results indicate the (AlxMg1-2xLix)Al2O4 stoichiometries x = 0.2…0.3 as most promising. The (AlxMg1-2xLix)Al2O4 electrolyte is a potential candidate for the all-spinel solid-state battery stack, with the material epitaxially grown between well-known spinel electrodes, such as LiyMn2O4 and Li4+3yTi5O12 (y = 0…1). Due to their identical crystal structure, a good electrolyte-electrode interface is expected.

  18. Intrinsic Surface Stability in LiMn2-xNixO4-d (x=0.45, 0.5) High Volt-age Spinel Materials for Lithium Ion Batteries

    SciTech Connect

    Carroll, Kyler J; Yang, Ming-Che; Veith, Gabriel M; Dudney, Nancy J; Meng, Ying Shirley

    2012-01-01

    This work reports the surface stability of the high voltage Li ion cathode LiMn2-xNixO4- (x= 0.5, 0.45) by comparing thin film and powder composite electrodes after cycling using X-ray photoelectron spectroscopy. The thin film electrodes offer the ability to probe the surface of the material without the need of a conductive agent and polymer binder typically used in composite electrodes. The results suggest that neither oxidation of PF6 to POF5 nor the decomposition of ethylene carbonate or dimethylene carbonate occurs on the surface of the spinel material. These results confirm the enhanced cycling stability and rate capability associated with the high voltage spinel material and suggests that the SEI layer forms due to the reaction of electrochemically inactive components in composite electrodes with the electrolyte.

  19. Cells having cathodes with thiocyanogen-containing cathode-active materials

    SciTech Connect

    Rao, B.M.

    1980-03-11

    An electric current-producing cell which contains: (A) an anode metal higher than hydrogen in the electromotive series and having an atomic number no greater than 30; (B) a cathode material containing thiocyanogen, said material being selected from the group consisting of: (I) thiocyanogen of the formula: (ScN)/sub 2/ (II) parathiocyanogen of the formula: (ScN)/sub x/ wherein X is greater than 2; (III) halothiocyanogen of the formula: YScN wherein Y is a halogen selected from the group consisting of F, Cl, Br and I; (IV) parahalothiocyanogen of the formula: (YScN)/sub y/ wherein Y is as described above and wherein Y is equal to or greater than 2; (V) perthiocyanogen complex of an amine; (VI) perthiocyanogen complex of an ammonium ion; (VII) thiocyanogen complex of a metal cation which is the same as the metal cation in the anode; (VIII) thiocyanogen complex of a metal cation which is higher in the electromotive series than the metal cation in the anode; (IX) cathode intercalated material having halothiocyanogen of paragraph (III) above intercalated therein; (X) cathode intercalated material having parahalothiocyanogen of paragraph (IV) above intercalated therein; (XI) polymeric thiocyanogen-containing material obtained from oxidation of a polyvinyl thiocyanate; (XII) ammonium thiocyanate salt complex of thiocyanogen of paragraph (I) above; (XIII) ammonium thiocyanate salt complex of parathiocyanogen of paragraph (II) above; (XIV) ammonium thiocyanate salt complex of halothiocyanogen of paragraph (III) above; and (XV) ammonium thiocyanate salt complex of parahalothiocyanogen of paragraph (IV) above; and (C) an electrolyte which is chemically inert with respect to said anode and said cathode.

  20. Synthesis and electrochemical characterizations of spinel LiMn1.94MO4 (M = Mn0.06, Mg0.06, Si0.06, (Mg0.03Si0.03)) compounds as cathode materials for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Zhao, Hongyuan; Liu, Xingquan; Cheng, Cai; Li, Qiang; Zhang, Zheng; Wu, Yue; Chen, Bing; Xiong, Weiqiang

    2015-05-01

    The spinel LiMn1.94MO4 (M = Mn0.06, Mg0.06, Si0.06, (Mg0.03Si0.03)) compounds are successfully synthesized by citric acid-assisted sol-gel method. The crystal structures and morphologies of synthesized compounds are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. All the compounds possess the cubic spinel structure of LiMn2O4 with space group of Fd-3m. The electrochemical properties of synthesized compounds are investigated by galvanostatic charge-discharge test, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results show that the Si-doping can increase the discharge capacity of LiMn2O4 due to the more expanded and regular MnO6 octahedra. In particular, for the LiMn1.94Mg0.03Si0.03O4 compound, the addition of Si4+ ions can make up for the shortage of Mg-doping in term of the discharge capacity. As a result, the Mg2+ and Si4+ co-doping has the effect of synergistic enhancement, which can make full use of the respective advantages of Mg-doping and Si-doping. The optimal LiMn1.94Mg0.03Si0.03O4 can deliver the initial discharge capacity of 128.3 mAh g-1 with good capacity retention of 92.8% after 100 cycles at 0.5 C in the voltage range of 3.20-4.35 V. Compared with the undoped LiMn2O4, the co-doped compound also presents superior rate performance, especially the capacity recovery performance.

  1. Process for Low Cost Domestic Production of LIB Cathode Materials

    SciTech Connect

    Thurston, Anthony

    2012-10-31

    The objective of the research was to determine the best low cost method for the large scale production of the Nickel-Cobalt-Manganese (NCM) layered cathode materials. The research and development focused on scaling up the licensed technology from Argonne National Laboratory in BASF’s battery material pilot plant in Beachwood Ohio. Since BASF did not have experience with the large scale production of the NCM cathode materials there was a significant amount of development that was needed to support BASF’s already existing research program. During the three year period BASF was able to develop and validate production processes for the NCM 111, 523 and 424 materials as well as begin development of the High Energy NCM. BASF also used this time period to provide free cathode material samples to numerous manufactures, OEM’s and research companies in order to validate the ma-terials. The success of the project can be demonstrated by the construction of the production plant in Elyria Ohio and the successful operation of that facility. The benefit of the project to the public will begin to be apparent as soon as material from the production plant is being used in electric vehicles.

  2. Functioning mechanism of AlF3 coating on the Li- and Mn-rich cathode materials

    SciTech Connect

    Zheng, Jianming; Gu, Meng; Xiao, Jie; Polzin, Bryant; Yan, Pengfei; Chen, Xilin; Wang, Chong M.; Zhang, Jiguang

    2014-11-25

    Li- and Mn-rich (LMR) material is a very promising cathode for lithium ion batteries because of their high theoretical energy density (~900 Wh kg-1) and low cost. However, their poor long-term cycling stability, voltage fade, and low rate capability are significant barriers hindered their practical applications. Surface coating, e.g. AlF3 coating, can significantly improve the capacity retention and enhance the rate capability. However, the fundamental mechanism of this improvement and the microstructural evolution related to the surface coating is still not well understood. Here, we report systematic studies of the microstructural changes of uncoated and AlF3-coated materials before and after cycling using aberration-corrected scanning/transmission electron microscopy and electron energy loss spectroscopy. The results reveal that surface coating can reduce the oxidation of electrolyte at high voltage, thus suppressing the accumulation of SEI layer on electrode particle surface. Surface coating also enhances structural stability of the surface region (especially the electrochemically transformed spinel-like phase), and protects the electrode from severe etching/corrosion by the acidic species in the electrolyte, therefore limiting the degradation of the material. Moreover, surface coating can alleviate the undesirable voltage fade by minimize layered-spinel phase transformation in the bulk region of the materials. These fundamental findings may also be widely applied to explain the functioning mechanism of other surface coatings used in a broad range of electrode materials.

  3. Synthesis, physical and electrochemical characterization of Gd (III) doped LiMn2O4 cathode material for lithium ion rechargeable batteries

    NASA Astrophysics Data System (ADS)

    Singhal, Rahul; Ram, Pura; Sharma, Rakesh Kumar

    2015-03-01

    The spinel structured LiMn2-xGdxO4 (x =0.01-0.05) have been synthesized via sol gel method. The physical and electrochemical characterization were carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy dispersive x-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR), UV-Vis spectroscopy, Raman spectroscopy, cyclic voltammetry and charge-discharge studies. The reversibility of synthesized cathode was supported through cyclic voltammetry in 3.0 - 4.5 voltage range. The initial charge discharge capacity of cathode materials was found in range 130-140 mAhg-1. The fabricated coin cell was tested up to 50 charge -discharge cycles with 0.5 C rate. The small amount of rare earth metal, Gd, doping showed improvement in capacity fading compared to LiMn2O4 cathode, offer its applicability for Li-ion rechargeable battery

  4. Novel Composite Materials for SOFC Cathode-Interconnect Contact

    SciTech Connect

    J. H. Zhu

    2009-07-31

    This report summarized the research efforts and major conclusions of our University Coal Research Project, which focused on developing a new class of electrically-conductive, Cr-blocking, damage-tolerant Ag-perovksite composite materials for the cathode-interconnect contact of intermediate-temperature solid oxide fuel cell (SOFC) stacks. The Ag evaporation rate increased linearly with air flow rate initially and became constant for the air flow rate {ge} {approx} 1.0 cm {center_dot} s{sup -1}. An activation energy of 280 KJ.mol{sup -1} was obtained for Ag evaporation in both air and Ar+5%H{sub 2}+3%H{sub 2}O. The exposure environment had no measurable influence on the Ag evaporation rate as well as its dependence on the gas flow rate, while different surface morphological features were developed after thermal exposure in the oxidizing and reducing environments. Pure Ag is too volatile at the SOFC operating temperature and its evaporation rate needs to be reduced to facilitate its application as the cathode-interconnect contact. Based on extensive evaporation testing, it was found that none of the alloying additions reduced the evaporation rate of Ag over the long-term exposure, except the noble metals Au, Pt, and Pd; however, these noble elements are too expensive to justify their practical use in contact materials. Furthermore, the addition of La{sub 0.8}Sr{sub 0.2}MnO{sub 3} (LSM) into Ag to form a composite material also did not significantly modify the Ag evaporation rate. The Ag-perovskite composites with the perovskite being either (La{sub 0.6}Sr{sub 0.4})(Co{sub 0.8}Fe{sub 0.2})O{sub 3} (LSCF) or LSM were systematically evaluated as the contact material between the ferritic interconnect alloy Crofer 22 APU and the LSM cathode. The area specific resistances (ASRs) of the test specimens were shown to be highly dependent on the volume percentage and the type of the perovskite present in the composite contact material as well as the amount of thermal cycling

  5. New Cathode Materials for Intermediate Temperature Solid Oxide Fuel Cells

    SciTech Connect

    Allan J. Jacobson

    2006-06-30

    Operation of SOFCs at intermediate temperatures (500-800 C) requires new combinations of electrolyte and electrode materials that will provide both rapid ion transport across the electrolyte and electrode-electrolyte interfaces and efficient electrocatalysis of the oxygen reduction and fuel oxidation reactions. This project concentrates on materials and issues associated with cathode performance that are known to become limiting factors as the operating temperature is reduced. The specific objectives of the proposed research are to develop cathode materials that meet the electrode performance targets of 1.0 W/cm{sup 2} at 0.7 V in combination with YSZ at 700 C and with GDC, LSGM or bismuth oxide based electrolytes at 600 C. The performance targets imply an area specific resistance of {approx}0.5 {Omega}cm{sup 2} for the total cell. The research strategy is to investigate both established classes of materials and new candidates as cathodes, to determine fundamental performance parameters such as bulk diffusion, surface reactivity and interfacial transfer, and to couple these parameters to performance in single cell tests. In this report, further measurements of the oxygen deficient double perovskite PrBaCo{sub 2}O{sub 5.5+{delta}} are reported. The high electronic conductivity and rapid diffusion and surface exchange kinetics of PBCO suggest its application as cathode material in intermediate temperature solid oxide fuel cells. Preliminary measurements in symmetric cells have shown low ASR values at 600 C. Here we describe the first complete cell measurements on Ni/CGO/CGO/PBCO/CGO cells.

  6. Few Atomic Layered Lithium Cathode Materials to Achieve Ultrahigh Rate Capability in Lithium-Ion Batteries.

    PubMed

    Tai, Zhixin; Subramaniyam, Chandrasekar M; Chou, Shu-Lei; Chen, Lingna; Liu, Hua-Kun; Dou, Shi-Xue

    2017-09-01

    The most promising cathode materials, including LiCoO2 (layered), LiMn2 O4 (spinel), and LiFePO4 (olivine), have been the focus of intense research to develop rechargeable lithium-ion batteries (LIBs) for portable electronic devices. Sluggish lithium diffusion, however, and unsatisfactory long-term cycling performance still limit the development of present LIBs for several applications, such as plug-in/hybrid electric vehicles. Motivated by the success of graphene and novel 2D materials with unique physical and chemical properties, herein, a simple shear-assisted mechanical exfoliation method to synthesize few-layered nanosheets of LiCoO2 , LiMn2 O4 , and LiFePO4 is used. Importantly, these as-prepared nanosheets with preferred orientations and optimized stable structures exhibit excellent C-rate capability and long-term cycling performance with much reduced volume expansion during cycling. In particular, the zero-strain insertion phenomenon could be achieved in 2-3 such layers of LiCoO2 electrode materials, which could open up a new way to the further development of next-generation long-life and high-rate batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Depth Profile Analysis of New Materials in Hollow Cathode Discharge

    SciTech Connect

    Djulgerova, R.; Mihailov, V.; Gencheva, V.; Popova, L.; Panchev, B.; Michaylova, V.; Szytula, A.; Gondek, L.; Dohnalik, T.M.; Petrovic, Z.Lj.

    2004-12-01

    In this review the possibility of hollow cathode discharge for depth profile analysis is demonstrated for several new materials: planar optical waveguides fabricated by Ag+-Na+ ion exchange process in glasses, SnO2 thin films for gas sensors modified by hexamethildisilazane after rapid thermal annealing, W- and WC- CVD layers deposited on Co-metalloceramics and WO3- CVD thin films deposited on glass. The results are compared with different standard techniques.

  8. Material and Energy Flows in the Production of Cathode and Anode Materials for Lithium Ion Batteries

    SciTech Connect

    Dunn, Jennifer B.; James, Christine; Gaines, Linda; Gallagher, Kevin; Dai, Qiang; Kelly, Jarod C.

    2015-09-01

    The Greenhouse gases, Regulated Emissions and Energy use in Transportation (GREET) model has been expanded to include four new cathode materials that can be used in the analysis of battery-powered vehicles: lithium nickel cobalt manganese oxide (LiNi0.4Co0.2Mn0.4O2 [NMC]), lithium iron phosphate (LiFePO4 [LFP]), lithium cobalt oxide (LiCoO2 [LCO]), and an advanced lithium cathode (0.5Li2MnO3∙0.5LiNi0.44Co0.25Mn0.31O2 [LMR-NMC]). In GREET, these cathode materials are incorporated into batteries with graphite anodes. In the case of the LMR-NMC cathode, the anode is either graphite or a graphite-silicon blend. Lithium metal is also an emerging anode material. This report documents the material and energy flows of producing each of these cathode and anode materials from raw material extraction through the preparation stage. For some cathode materials, we considered solid state and hydrothermal preparation methods. Further, we used Argonne National Laboratory’s Battery Performance and Cost (BatPaC) model to determine battery composition (e.g., masses of cathode, anode, electrolyte, housing materials) when different cathode materials were used in the battery. Our analysis concluded that cobalt- and nickel-containing compounds are the most energy intensive to produce.

  9. Synthesis of nanocrystalline (Co, Ni)Al2O4 spinel powder by mechanical milling of quasicrystalline materials.

    PubMed

    Yadav, T P; Mukhopadhyay, N K; Tiwari, R S; Srivastava, O N

    2007-02-01

    In the present study, attempts have been made to synthesize the nano-crystalline (Co, Ni)Al2O4 spinel powders by ball milling and subsequent annealing. An alloy of Al70Co15Ni15, exhibiting the formation of a complex intermetallic compound known as decagonal quasicrystal is selected as the starting material for mechanical milling. It is interesting to note that this alloy is close to the stoichiometry of aluminum and transition metal atoms required to form the aluminate spinel. The milling was carried out in an attritor mill at 400 rpm for 40 hours with ball to powder ratio of 20 : 1 in hexane medium. Subsequent to this annealing was performed in an air ambience for 10, 20, and 40 h at 600 degrees C in side the furnace in order to oxidize the decagonal phase and finally to form the spinel structure. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed the formation of nano-sized decagonal phase after milling and then (Co, Ni)Al2O4 spinel type phase after annealing. The XRD studies reveal the lattice parameter to be 8.075 angstroms and the lattice strain as 0.6%. The XRD and TEM explorations of spinel phase indicate the average grain size to be approximately 40 nm.

  10. Material and Energy Flows in the Production of Cathode and Anode Materials for Lithium Ion Batteries

    SciTech Connect

    Dunn, Jennifer B.; James, Christine; Gaines, Linda G.; Gallagher, Kevin

    2014-09-30

    The Greenhouse gases, Regulated Emissions and Energy use in Transportation (GREET) model has been expanded to include four new cathode materials that can be used in the analysis of battery-powered vehicles: lithium nickel cobalt manganese oxide (LiNi0.4Co0.2Mn0.4O2 [NMC]), lithium iron phosphate (LiFePO4 [LFP]), lithium cobalt oxide (LiCoO2 [LCO]), and an advanced lithium cathode (0.5Li2MnO3∙0.5LiNi0.44Co0.25Mn0.31O2 [LMR-NMC]). In GREET, these cathode materials are incorporated into batteries with graphite anodes. In the case of the LMR-NMC cathode, the anode is either graphite or a graphite-silicon blend. This report documents the material and energy flows of producing each of these cathode and anode materials from raw material extraction through the preparation stage. For some cathode materials, we considered solid state and hydrothermal preparation methods. Further, we used Argonne National Laboratory’s Battery Performance and Cost (BatPaC) model to determine battery composition (e.g., masses of cathode, anode, electrolyte, housing materials) when different cathode materials were used in the battery. Our analysis concluded that cobalt- and nickel-containing compounds are the most energy intensive to produce.

  11. Probing the initiation of voltage decay in Li-rich layered cathode materials at the atomic scale

    SciTech Connect

    Wu, Yan; Ma, Cheng; Yang, Jihui; Li, Zicheng; Allard, Jr., Lawrence Frederick; Liang, Chengdu; Chi, Miaofang

    2015-01-01

    Li-rich layered oxides hold great promise for improving the energy density of present-day Li-ion batteries. However, their application is limited by the voltage decay upon cycling, and the origin of such a phenomenon is poorly understood. A major issue is determining the voltage range over which detrimental reactions originate. In the present study, a unique yet effective approach was employed to probe this issue. Instead of studying the materials during the first cycle, electrochemical behavior and evolution of the atomic structures were compared in extensively cycled specimens under varied charge/discharge voltages. With the upper cutoff voltage lowered from 4.8 to 4.4 V, the voltage decay ceased to occur even after 60 cycles. In the meantime, the material maintained its layered structure without any spinel phase emerging at the surface, which is unambiguously shown by the atomic-resolution Z-contrast imaging and electron energy loss spectroscopy. These results have conclusively demonstrated that structural/chemical changes responsible for the voltage decay began between 4.4 and 4.8 V, where the layered-to-spinel transition was the most dramatic structural change observed. Thus, this discovery lays important groundwork for the mechanistic understanding of the voltage decay in Li-rich layered cathode materials.

  12. Probing the initiation of voltage decay in Li-rich layered cathode materials at the atomic scale

    DOE PAGES

    Wu, Yan; Ma, Cheng; Yang, Jihui; ...

    2015-01-01

    Li-rich layered oxides hold great promise for improving the energy density of present-day Li-ion batteries. However, their application is limited by the voltage decay upon cycling, and the origin of such a phenomenon is poorly understood. A major issue is determining the voltage range over which detrimental reactions originate. In the present study, a unique yet effective approach was employed to probe this issue. Instead of studying the materials during the first cycle, electrochemical behavior and evolution of the atomic structures were compared in extensively cycled specimens under varied charge/discharge voltages. With the upper cutoff voltage lowered from 4.8 tomore » 4.4 V, the voltage decay ceased to occur even after 60 cycles. In the meantime, the material maintained its layered structure without any spinel phase emerging at the surface, which is unambiguously shown by the atomic-resolution Z-contrast imaging and electron energy loss spectroscopy. These results have conclusively demonstrated that structural/chemical changes responsible for the voltage decay began between 4.4 and 4.8 V, where the layered-to-spinel transition was the most dramatic structural change observed. Thus, this discovery lays important groundwork for the mechanistic understanding of the voltage decay in Li-rich layered cathode materials.« less

  13. Apparatus and method for treating a cathode material provided on a thin-film substrate

    DOEpatents

    Hanson, Eric J.; Kooyer, Richard L.

    2003-01-01

    An apparatus and method for treating a cathode material provided on a surface of a continuous thin-film substrate and a treated thin-film cathode having increased smoothness are disclosed. A web of untreated cathode material is moved between a feed mechanism and a take-up mechanism, and passed through a treatment station. The web of cathode material typically includes areas having surface defects, such as prominences extending from the surface of the cathode material. The surface of the cathode material is treated with an abrasive material to reduce the height of the prominences so as to increase an 85 degree gloss value of the cathode material surface by at least approximately 10. The web of cathode material may be subjected to a subsequent abrasive treatment at the same or other treatment station. Burnishing or lapping film is employed at a treatment station to process the cathode material. An abrasive roller may alternatively be used to process the web of cathode material. The apparatus and method of the present invention may also be employed to treat the surface of a lithium anode foil so as to cleanse and reduce the roughness of the anode foil surface.

  14. Apparatus and method for treating a cathode material provided on a thin-film substrate

    SciTech Connect

    Hanson, Eric J.; Kooyer, Richard L.

    2001-01-01

    An apparatus and method for treating a cathode material provided on a surface of a continuous thin-film substrate and a treated thin-film cathode having increased smoothness are disclosed. A web of untreated cathode material is moved between a feed mechanism and a take-up mechanism, and passed through a treatment station. The web of cathode material typically includes areas having surface defects, such as prominences extending from the surface of the cathode material. The surface of the cathode material is treated with an abrasive material to reduce the height of the prominences so as to increase an 85 degree gloss value of the cathode material surface by at least approximately 10. The web of cathode material may be subjected to a subsequent abrasive treatment at the same or other treatment station. Burnishing or lapping film is employed at a treatment station to process the cathode material. An abrasive roller may alternatively be used to process the web of cathode material. The apparatus and method of the present invention may also be employed to treat the surface of a lithium anode foil so as to cleanse and reduce the roughness of the anode foil surface.

  15. Triple-conducting layered perovskites as cathode materials for proton-conducting solid oxide fuel cells.

    PubMed

    Kim, Junyoung; Sengodan, Sivaprakash; Kwon, Goeun; Ding, Dong; Shin, Jeeyoung; Liu, Meilin; Kim, Guntae

    2014-10-01

    We report on an excellent anode-supported H(+) -SOFC material system using a triple conducting (H(+) /O(2-) /e(-) ) oxide (TCO) as a cathode material for H(+) -SOFCs. Generally, mixed ionic (O(2-) ) and electronic conductors (MIECs) have been selected as the cathode material of H(+) -SOFCs. In an H(+) -SOFC system, however, MIEC cathodes limit the electrochemically active sites to the interface between the proton conducting electrolyte and the cathode. New approaches to the tailoring of cathode materials for H(+) -SOFCs should therefore be considered. TCOs can effectively extend the electrochemically active sites from the interface between the cathode and the electrolyte to the entire surface of the cathode. The electrochemical performance of NBSCF/BZCYYb/BZCYYb-NiO shows excellent long term stability for 500 h at 1023 K with high power density of 1.61 W cm(-2) .

  16. Effect of Surface Modification on Nano-Structured LiNi(0.5)Mn(1.5)O4 Spinel Materials.

    PubMed

    Cho, Hyung-Man; Chen, Michael Vincent; MacRae, Alex C; Meng, Ying Shirley

    2015-08-05

    Fine-tuning of particle size and morphology has been shown to result in differential material performance in the area of secondary lithium-ion batteries. For instance, reduction of particle size to the nanoregime typically leads to better transport of electrochemically active species by increasing the amount of reaction sites as a result of higher electrode surface area. The spinel-phase oxide LiNi0.5Mn1.5O4 (LNMO), was prepared using a sol-gel based template synthesis to yield nanowire morphology without any additional binders or electronic conducting agents. Therefore, proper experimentation of the nanosize effect can be achieved in this study. The spinel phase LMNO is a high energy electrode material currently being explored for use in lithium-ion batteries, with a specific capacity of 146 mAh/g and high-voltage plateau at ∼4.7 V (vs Li/Li(+)). However, research has shown that extensive electrolyte decomposition and the formation of a surface passivation layer results when LMNO is implemented as a cathode in electrochemical cells. As a result of the high surface area associated with nanosized particles, manganese ion dissolution results in capacity fading over prolonged cycling. In order to prevent these detrimental effects without compromising electrochemical performance, various coating methods have been explored. In this work, TiO2 and Al2O3 thin films were deposited using atomic layer deposition (ALD) on the surface of LNMO particles. This resulted in effective surface protection by prevention of electrolyte side reactions and a sharp reduction in resistance at the electrode/electrolyte interface region.

  17. High Capacity Cathode Materials for Next Generation Energy Storage

    NASA Astrophysics Data System (ADS)

    Papandrea, Benjamin John

    Energy storage devices are of increasing importance for applications in mobile electronics, hybrid electric vehicles, and can also play a critical role in renewable energy harvesting, conversion and storage. Since its commercial inception in the 1990's, the lithium-ion battery represents the dominant energy storage technology for mobile power supply today. However, the total capacity of lithium-ion batteries is largely limited by the theoretical capacities of the cathode materials such as LiCoO2 (272 mAh g-1), and LiFePO4 (170 mAh g-1), and cannot satisfy the increasing consumer demand, thus new cathode materials with higher capacities must be explored. Two of the most promising cathode materials with significantly larger theoretical capacities are sulfur (1675 mAh g-1) and air, specifically the oxygen (3840 mAh g-1). However, the usage of either of these cathodic materials is plagued with numerous issues that must be overcome before their commercialization. In the first part of my dissertation, we investigated the usage of a three-dimensional graphene membrane for a high energy density lithium-air (Li-Air) battery in ambient condition. One of the issues with Li-Air batteries is the many side reaction that can occur during discharge in ambient condition, especially with water vapor. Using a hydrophobic tortuous three-dimensional graphene membrane we are able to inhibit the diffusion of water vapor and create a lithium-air battery that cycles over 2000 times with a capacity limited at 140 mAh g-1, over 100 cycles with a capacity limited at 1425 mAh g-1, and over 20 cycles at the high capacity of 5700 mAh g-1. In the second part of my dissertation, we investigate the usage of a three-dimensional graphene aerogel to maximize the loading of sulfur to create a freestanding electrode with high capacity for a lithium-sulfur (Li-S) battery. We demonstrated that our three-dimensional graphene aerogel could sustain a loading of 95% by weight, and we achieved a capacity of

  18. Copper oxide as a high temperature battery cathode material

    NASA Astrophysics Data System (ADS)

    Ritchie, A. G.; Mullins, A. P.

    1994-10-01

    Copper oxide has been tested as a cathode material for high temperature primary reserve thermal batteries in single cells at 530 to 600 C and at current densities of 0.1 to 0.25 A cm(exp -2) using lithium-aluminium alloy anodes and lithium fluoride-lithium chloride-lithium bromide molten salt electrolytes. Initial on-load voltages were around 2.3 V, falling to 1.5 V after about 0.5 F mol(exp -1) had been withdrawn. Lithium copper oxide, LiCu2O2, and cuprous oxide, Cu2O, were identified as discharge products.

  19. Renewable cathode materials from biopolymer/conjugated polymer interpenetrating networks.

    PubMed

    Milczarek, Grzegorz; Inganäs, Olle

    2012-03-23

    Renewable and cheap materials in electrodes could meet the need for low-cost, intermittent electrical energy storage in a renewable energy system if sufficient charge density is obtained. Brown liquor, the waste product from paper processing, contains lignin derivatives. Polymer cathodes can be prepared by electrochemical oxidation of pyrrole to polypyrrole in solutions of lignin derivatives. The quinone group in lignin is used for electron and proton storage and exchange during redox cycling, thus combining charge storage in lignin and polypyrrole in an interpenetrating polypyrrole/lignin composite.

  20. Renewable Cathode Materials from Biopolymer/Conjugated Polymer Interpenetrating Networks

    NASA Astrophysics Data System (ADS)

    Milczarek, Grzegorz; Inganäs, Olle

    2012-03-01

    Renewable and cheap materials in electrodes could meet the need for low-cost, intermittent electrical energy storage in a renewable energy system if sufficient charge density is obtained. Brown liquor, the waste product from paper processing, contains lignin derivatives. Polymer cathodes can be prepared by electrochemical oxidation of pyrrole to polypyrrole in solutions of lignin derivatives. The quinone group in lignin is used for electron and proton storage and exchange during redox cycling, thus combining charge storage in lignin and polypyrrole in an interpenetrating polypyrrole/lignin composite.

  1. Anti-Perovskite Li-Battery Cathode Materials.

    PubMed

    Lai, Kwing To; Antonyshyn, Iryna; Prots, Yurii; Valldor, Martin

    2017-07-19

    Through single-step solid-state reactions, a series of novel bichalcogenides with the general composition (Li2Fe)ChO (Ch = S, Se, Te) are successfully synthesized. (Li2Fe)ChO (Ch = S, Se) possess cubic anti-perovskite crystal structures, where Fe and Li are completely disordered on a common crystallographic site (3c). According to Goldschmidt calculations, Li(+) and Fe(2+) are too small for their common atomic position and exhibit large thermal displacements in the crystal structure models, implying high cation mobility. Both compounds (Li2Fe)ChO (Ch = S, Se) were tested as cathode materials against graphite anodes (single cells); They perform outstandingly at very high charge rates (270 mA g(-1), 80 cycles) and, at a charge rate of 30 mA g(-1), exhibit charge capacities of about 120 mA h g(-1). Compared to highly optimized Li1-xCoO2 cathode materials, these novel anti-perovskites are easily produced at cost reductions by up to 95% and, yet, possess a relative specific charge capacity of 75%. Moreover, these iron-based anti-perovskites are comparatively friendly to the environment and (Li2Fe)ChO (Ch = S, Se) melt congruently; the latter is advantageous for manufacturing pure materials in large amounts.

  2. A study of layered lithium manganese oxide cathode materials

    NASA Astrophysics Data System (ADS)

    Eriksson, Tom A.; Doeff, Marca M.

    Substituted layered sodium manganese oxide bronzes with the P2 structure were prepared by glycine-nitrate combustion synthesis. The Na in the as-prepared materials could be completely ion-exchanged for Li under mild conditions. All lithium manganese oxide compounds obtained after ion-exchange have O2 stacking of the layers. Cyclic voltammetry and stepped potential experiments on lithium cells containing these materials show that the main redox reaction around 3.1 V is a diffusion-controlled process and is completely reversible. O2-Li 0.6[Al 0.1Mn 0.85□ 0.05]O 2 and O2-Li 0.6[Ni 0.1Mn 0.85□ 0.05]O 2 are particularly promising as cathode materials in lithium cells because of the high reversible discharge capacities (180 mAh/g).

  3. Discharge characteristics of lithium/molten nitrate thermal battery cells using silver salts as solid cathode materials

    NASA Astrophysics Data System (ADS)

    McManis, G. E.; Miles, M. H.; Fletcher, A. N.

    1985-12-01

    Thermal battery cells using molten nitrate electrolytes and liquid lithium anodes have been evaluated using several silver salts with low solubility in molten nitrates as solid cathode materials. These cathode materials do not readily diffuse into the anolyte and, thus, do not have parasitic reactions with the lithium anode. Furthermore, the solid cathode materials have voltammetric characteristics as favorable as many soluble silver salt cathodes. This paper presents the effects of temperature, current density, and cathode material on cell discharge characteristics.

  4. Copper sulfates as cathode materials for Li batteries

    NASA Astrophysics Data System (ADS)

    Schwieger, Jonathan N.; Kraytsberg, Alexander; Ein-Eli, Yair

    As lithium battery technology sets out to bridge the gap between portable electronics and the electrical automotive industry, cathode materials still stand as the bottleneck regarding performances. In the realm of highly attractive polyanion-type structures as high-voltage cathode materials, the sulfate group (SO 4) 2- possesses an acknowledged superiority over other contenders in terms of open circuit voltage arising from the inductive effect of strong covalent S-O bonds. In parallel, novel lithium insertion mechanisms are providing alternatives to traditional intercalation, enabling reversible multi-electron processes securing high capacities. Combining both of these advantageous features, we report here the successful electrochemical reactivity of copper sulfate pentahydrate (CuSO 4·5H 2O) with respect to lithium insertion via a two-electron displacement reaction entailing the extrusion of metallic copper at a dual voltage of 3.2 V and 2.7 V followed by its reversible insertion at 3.5 V and 3.8 V. At this stage, cyclability was still shown to be limited due to the irreversible degradation to a monohydrate structure owing to constitutional water loss.

  5. Polaron formation and transport in olivine cathode materials

    NASA Astrophysics Data System (ADS)

    Johannes, Michelle; Hoang, Khang

    2011-03-01

    One of the critical factors limiting Li ion battery performance is electronic conduction through the cathode material. In the olivine structure type materials, such as LiFe PO4 , the parent materials are insulators with a gap of approximately 4 (or more) eV. The withdrawal of an electron results not in a band-type hole state, but rather a localized polaronic state. Transport then occurs via hopping of the polaron through the crystal. The measured electronic conduction in olivine materials depends on the transition metal cation type. In this study, we use density functional theory to compare formation of polarons in olivine materials with different transition metal cations: Mn, Fe, Co, and Ni. We show that the underlying electronic structure of the fully lithiated material (or fully delithiated material) essentially determines whether or not polaron formation is possible in localized d -states or whether the holes that result from adding or removing an electron reside in oxygen-derived states. We also investigate the facility of polaronic hopping by calculating the barrier between adjacent polaron sites in each of the four materials.

  6. Reaction mechanism and thermal stability study on cathode materials for rechargeable lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Fang, Jin

    Olivine-type lithium iron phosphate has been a very promising cathode material since it was proposed by Padhi in 1997, low-cost, environmental friendly and stable structure ensure the commercialization of LiFePO 4. In LiFePO4, during charge and discharge process, Li ions are transferred between two phases, Li-poor LialphaFePO 4 and Li-rich Li1-betaFePO4, which implies a significant energy barrier for the new phase nucleation and interface growth, contrary to the fast reaction kinetics experimentally observed. The understanding of the lithiation and delithiation mechanism of this material has spurred a lot of research interests. Many theory models have been proposed to explain the reaction mechanism of LiFePO4, among them, the single phase model claims that the reaction goes through a metastable single phase, and the over potential required to form this single phase is about 30mV, so we studied the driving force to transport lithium ions between Lialpha FePO4 and Li1-betaFePO4 phases and compared the particle sizes effect. Experiment results shows that, the nano-sized (30nm) LiFePO4 has wider solid solution range, lower solid solution formation temperature and faster kinetics than normal LiFePO4 (150nm). Also a 20mV over potential was observed in both samples, either after relaxing the FePO4/LiFePO4 system to equilibrium or transport lithium from one side to the other side, the experiment result is corresponding to theoretical calculation; indicates the reaction might go through single-phase reaction mechanism. The energy and power density of lithium ion battery largely depend on cathode materials. Mn substituted LiFePO4 has a higher voltage than LiFePO4, which results a higher theoretical energy density. Safety issue is one of the most important criterions for batteries, since cathode materials need to maintain stable structure during hundreds of charge and discharge cycles and ranges of application conditions. We have reported that iron-rich compound o-Fe1-yMnyPO4

  7. Rapid synthesis of monodispersed highly porous spinel nickel cobaltite (NiCo2O4) electrode material for supercapacitors

    NASA Astrophysics Data System (ADS)

    Naveen, A. Nirmalesh; Selladurai, S.

    2015-06-01

    Monodispersed highly porous spinel nickel cobaltite electrode material was successfully synthesized in a short time using combustion technique. Single phase cubic nature of the spinel nickel cobaltite with average crystallite size of 24 nm was determined from X-ray diffraction study. Functional groups present in the compound were determined from FTIR study and it further confirms the spinel formation. FESEM images reveal the porous nature of the prepared material and uniform size distribution of the particles. Electrochemical evaluation was performed using Cyclic Voltammetry (CV) technique, Chronopotentiometry (CP) and Electrochemical Impedance Spectroscopy (EIS). Results reveal the typical pseudocapacitive behaviour of the material. Maximum capacitance of 754 F/g was calculated at the scan rate of 5 mV/s, high capacitance was due to the unique porous morphology of the electrode. Nyquist plot depicts the low resistance and good electrical conductivity of nickel cobaltite. It has been found that nickel cobaltite prepared by this typical method will be a potential electrode material for supercapcitor application.

  8. Cathode materials for lithium-ion batteries: Synthesis, analysis, and thermal studies

    NASA Astrophysics Data System (ADS)

    Kim, Jeom-Soo

    2001-12-01

    The effect of synthesis technique was studied with two representative techniques such as solid-state reaction (SSR) and sol-gel methods used for LixMn2O4 (x = 1.03) preparation. For the in-cell performance of LixMn2O4 as electrode material, variation in processing temperature and intermittent grinding were found to be the key parameters of synthesis. The characteristics of powder synthesized by these different methods were investigated and compared with stoichiometric LiMn2O4 spinel using a combination of physicochemical and electrochemical techniques. Physicochemical characteristics investigated including phase identification, particle size, density, BET surface area, and composition. The electrochemical performance was characterized with 2016 coin type cells, using a battery tester. In addition, the electro-analytical response was studied using slow sweep cyclic voltammetry (SSCV) and current pulse response (CPR). The hybrid pulse power characterization (HPPC), one of the test profiles proposed by the Partnership for New Generation Vehicle (PNGV), was applied to check the possibility of using LixMn 2O4 electrodes in HEV batteries. Chemical diffusion coefficients of lithium (D Li+) in spinel LixMn2O 4 were measured by various electrochemical techniques such as potentiostatic intermittent titration technique (PITT), electrochemical impedance spectroscopy (EIS), and galvanostatic intermittent titration technique (GITT). DLi+ varied with x in LixMn2O4, showing strong dependence on the concentration of lithium. The thermal behavior of major cathode materials for Li-ion battery (LiCoO 2, LiNi0.8Co0.2O2, and LiMn2O 4) was investigated using an isothermal microcalorimeter, in combination with a battery tester. The total heat generation rate was found to be dependent on the concentration of lithium in LixMn2O4 and LixCoO2 while it was relatively constant in the case of LixNi0.8Co0.2O2. The area-specific impedance (ASI) measured in these tests indicated that the heat

  9. Performance and stability of different cathode base materials for use in microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Janicek, Anthony; Fan, Yanzhen; Liu, Hong

    2015-04-01

    Metal supporting materials are increasingly being used as base materials for microbial fuel cell (MFC) cathodes. However, the potential for corrosion may limit their use as base materials of MFCs during scale-up and long-term operation. In this study, the electrochemical performance, power generation in MFCs, hydrostatic pressure tolerance, and stability of activated carbon (catalyst) cathodes with carbon cloth or different size metal mesh as base materials are investigated. Electrochemical testing results show that the finest stainless steel mesh (250 × 250 openings per inch) outperforms carbon cloth cathodes by 10-40% at current densities ranging from 6 to 11.2 A m-2 over the typical cathode operating range of 0.1 V-0 V. When tested in MFCs, however, carbon cloth based cathodes out perform all stainless steel mesh cathodes by as much as 34%, reaching 1.72 W m-2; probably due to the corrosion and salt build-up on the surface of the stainless steel mesh cathodes. Carbon cloth cathodes also maintained high static pressure heads of 1.9 m. The high electrochemical performance, hydrostatic pressure tolerance, and corrosion resistance of carbon cloth suggest that carbon fiber based materials may be more suitable than metal based materials for use as MFC cathodes base material for some applications.

  10. K(+)-doped Li(1.2)Mn(0.54)Co(0.13)Ni(0.13)O2: a novel cathode material with an enhanced cycling stability for lithium-ion batteries.

    PubMed

    Li, Qi; Li, Guangshe; Fu, Chaochao; Luo, Dong; Fan, Jianming; Li, Liping

    2014-07-09

    Li-rich layered oxides have attracted much attention for their potential application as cathode materials in lithium ion batteries, but still suffer from inferior cycling stability and fast voltage decay during cycling. How to eliminate the detrimental spinel growth is highly challenging in this regard. Herein, in situ K(+)-doped Li1.20Mn0.54Co0.13Ni0.13O2 was successfully prepared using a potassium containing α-MnO2 as the starting material. A systematic investigation demonstrates for the first time, that the in situ potassium doping stabilizes the host layered structure by prohibiting the formation of spinel structure during cycling. This is likely due to the fact that potassium ions in the lithium layer could weaken the formation of trivacancies in lithium layer and Mn migration to form spinel structure, and that the large ionic radius of potassium could possibly aggravate steric hindrance for spinel growth. Consequently, the obtained oxides exhibited a superior cycling stability with 85% of initial capacity (315 mA h g(-1)) even after 110 cycles. The results reported in this work are fundamentally important, which could provide a vital hint for inhibiting the undesired layered-spinel intergrowth with alkali ion doping and might be extended to other classes of layered oxides for excellent cycling performance.

  11. New Cathode Materials for Intermediate Temperature Solid Oxide Fuel Cells

    SciTech Connect

    Allan J. Jacobson

    2006-09-30

    Operation of SOFCs at intermediate temperatures (500-800 C) requires new combinations of electrolyte and electrode materials that will provide both rapid ion transport across the electrolyte and electrode-electrolyte interfaces and efficient electrocatalysis of the oxygen reduction and fuel oxidation reactions. This project concentrates on materials and issues associated with cathode performance that are known to become limiting factors as the operating temperature is reduced. The specific objectives of the proposed research are to develop cathode materials that meet the electrode performance targets of 1.0 W/cm{sup 2} at 0.7 V in combination with YSZ at 700 C and with GDC, LSGM or bismuth oxide based electrolytes at 600 C. The performance targets imply an area specific resistance of {approx}0.5 {Omega}cm{sup 2} for the total cell. The research strategy is to investigate both established classes of materials and new candidates as cathodes, to determine fundamental performance parameters such as bulk diffusion, surface reactivity and interfacial transfer, and to couple these parameters to performance in single cell tests. The initial choices for study were perovskite oxides based on substituted LaFeO{sub 3} (P1 compositions), where significant data in single cell tests exist at PNNL for example, for La{sub 0.8}Sr{sub 0.2}FeO{sub 3} cathodes on both YSZ and CSO/YSZ. The materials selection was then extended to La{sub 2}NiO{sub 4} compositions (K1 compositions), and then in a longer range task we evaluated the possibility of completely unexplored group of materials that are also perovskite related, the ABM{sub 2}O{sub 5+{delta}}. A key component of the research strategy was to evaluate for each cathode material composition, the key performance parameters, including ionic and electronic conductivity, surface exchange rates, stability with respect to the specific electrolyte choice, and thermal expansion coefficients. In the initial phase, we did this in parallel with

  12. Mercury vapor hollow cathode component studies. [emissive materials for ion thruster requirements

    NASA Technical Reports Server (NTRS)

    Zuccaro, D. E.

    1973-01-01

    An experimental study of starting and operating characteristics of conventional hollow cathodes and of hollow cathodes without alkaline earth emissive materials demonstrated that the emissive mix is essential to obtain the desired cathode operation. Loss of the emissive mix by evaporation and chemical reaction was measured. New insert designs consisting of emissive mix supported on nickel and of barium impregnated porous tungsten were studied. Cathodes with a modified orifice geometry operated in a low voltage, 'spot' mode over a broad range of discharge current. Thermal degradation tests on cathode heaters showed the flame sprayed SERT II type to be the most durable at high temperatures. Thermal shock was observed to be a significant factor in limiting cathode heater life. A cathode having a barium impregnated porous tungsten tip and a heater which is potted in sintered alumina was found to have favorable operating characteristics.

  13. Novel synthesis of highly porous spinel cobaltite (NiCo2O4) electrode material for supercapacitor applications

    NASA Astrophysics Data System (ADS)

    Naveen, A. Nirmalesh; Selladurai, S.

    2014-04-01

    High performing porous nickel cobaltite (NiCo2O4) nanomaterial is prepared using novel cost effective auto combustion technique. Physical characterization reveals the formation of nickel rich spinel cobaltitie with average crystallite size of 17 nm. Electrochemical evaluation of the sample is carried using cyclic voltammetry (CV), chronopotentiometry (CP) and AC impedance techniques. The Pseudocapacitive nature of the material is observed from CV and CP studies exhibiting a high specific capacitance of 772 Fg-1 at a current density of 1 Ag-1. The low resistive behavior of the material is seen from the impedance spectra, projecting nickel cobaltite as promising material for supercapcitor applications.

  14. Direct regeneration of recycled cathode material mixture from scrapped LiFePO4 batteries

    NASA Astrophysics Data System (ADS)

    Li, Xuelei; Zhang, Jin; Song, Dawei; Song, Jishun; Zhang, Lianqi

    2017-03-01

    A new green recycling process (named as direct regeneration process) of cathode material mixture from scrapped LiFePO4 batteries is designed for the first time. Through this direct regeneration process, high purity cathode material mixture (LiFePO4 + acetylene black), anode material mixture (graphite + acetylene black) and other by-products (shell, Al foil, Cu foil and electrolyte solvent, etc.) are recycled from scrapped LiFePO4 batteries with high yield. Subsequently, recycled cathode material mixture without acid leaching is further directly regenerated with Li2CO3. Direct regeneration procedure of recycled cathode material mixture from 600 to 800 °C is investigated in detail. Cathode material mixture regenerated at 650 °C display excellent physical, chemical and electrochemical performances, which meet the reuse requirement for middle-end Li-ion batteries. The results indicate the green direct regeneration process with low-cost and high added-value is feasible.

  15. Optimization of Layered Cathode Materials for Lithium-Ion Batteries

    PubMed Central

    Julien, Christian; Mauger, Alain; Zaghib, Karim; Groult, Henri

    2016-01-01

    This review presents a survey of the literature on recent progress in lithium-ion batteries, with the active sub-micron-sized particles of the positive electrode chosen in the family of lamellar compounds LiMO2, where M stands for a mixture of Ni, Mn, Co elements, and in the family of yLi2MnO3•(1 − y)LiNi½Mn½O2 layered-layered integrated materials. The structural, physical, and chemical properties of these cathode elements are reported and discussed as a function of all the synthesis parameters, which include the choice of the precursors and of the chelating agent, and as a function of the relative concentrations of the M cations and composition y. Their electrochemical properties are also reported and discussed to determine the optimum compositions in order to obtain the best electrochemical performance while maintaining the structural integrity of the electrode lattice during cycling. PMID:28773717

  16. Nanostructured material for advanced energy storage : magnesium battery cathode development.

    SciTech Connect

    Sigmund, Wolfgang M.; Woan, Karran V.; Bell, Nelson Simmons

    2010-11-01

    Magnesium batteries are alternatives to the use of lithium ion and nickel metal hydride secondary batteries due to magnesium's abundance, safety of operation, and lower toxicity of disposal. The divalency of the magnesium ion and its chemistry poses some difficulties for its general and industrial use. This work developed a continuous and fibrous nanoscale network of the cathode material through the use of electrospinning with the goal of enhancing performance and reactivity of the battery. The system was characterized and preliminary tests were performed on the constructed battery cells. We were successful in building and testing a series of electrochemical systems that demonstrated good cyclability maintaining 60-70% of discharge capacity after more than 50 charge-discharge cycles.

  17. Hydrogen Induced Stress Cracking of Materials Under Cathodic Protection

    NASA Astrophysics Data System (ADS)

    LaCoursiere, Marissa P.

    Hydrogen embrittlement of AISI 4340, InconelRTM 718, Alloy 686 and Alloy 59 was studied using slow strain rate tests of both smooth and notched cylindrical specimens. Two heat treatments of the AISI 4340 material were used as a standard for two levels of yield strength: 1479 MPa, and 1140 MPa. A subset of the 1140 MPa AISI 4340 material also underwent plasma nitriding. The InconelRTM 718 material was hardened following AMS 5663M to obtain a yield strength of 1091 MPa. The Alloy 686 material was obtained in the Grade 3 condition with a minimum yield strength of 1034 MPa. The Alloy 59 material was obtained with a cold worked condition similar to the Alloy 686 and with a minimum yield strength of 1034 MPa. Ninety-nine specimens were tested, including smooth cylindrical tensile test specimens and smooth and notched cylindrical slow strain rate tensile tests specimens. Testing included specimens that had been precharged with hydrogen in 3.5% NaCl at 50°C for 2 weeks (AISI 4340), 4 weeks (InconelRTM 718, Alloy 686, Alloy 59) and 16 weeks (InconelRTM 718, Alloy 686, Alloy 59) using a potentiostat to deliver a cathodic potential of -1100 mV vs. SCE. The strain rate over the gauge section for the smooth specimens and in the notch root for the notched specimens was 1 x 10-6 /s. It was found that the AISI 4340 was highly embrittled in simulated ocean water when compared to the nickel based superalloys. The higher strength AISI 4340 showed much more embrittlement, as expected. Testing of the AISI 4340 at both 20°C and 4°C showed that the temperature had no effect on the hydrogen embrittlement response. The InconelRTM 718 was highly embrittled when precharged, although it only showed low levels of embrittlement when unprecharged. Both the Alloy 686 and Alloy 59 showed minimal embrittlement in all conditions. Therefore, for the materials examined, the use of Alloy 686 and Alloy 59 for components in salt water environments when under a cathodic potential of -1100 mV vs. SCE is

  18. The influence of cathode material on electrochemical degradation of trichloroethylene in aqueous solution.

    PubMed

    Rajic, Ljiljana; Fallahpour, Noushin; Podlaha, Elizabeth; Alshawabkeh, Akram

    2016-03-01

    In this study, different cathode materials were evaluated for electrochemical degradation of aqueous phase trichloroethylene (TCE). A cathode followed by an anode electrode sequence was used to support reduction of TCE at the cathode via hydrodechlorination (HDC). The performance of iron (Fe), copper (Cu), nickel (Ni), aluminum (Al) and carbon (C) foam cathodes was evaluated. We tested commercially available foam materials, which provide large electrode surface area and important properties for field application of the technology. Ni foam cathode produced the highest TCE removal (68.4%) due to its high electrocatalytic activity for hydrogen generation and promotion of HDC. Different performances of the cathode materials originate from differences in the bond strength between atomic hydrogen and the material. With a higher electrocatalytic activity than Ni, Pd catalyst (used as cathode coating) increased TCE removal from 43.5% to 99.8% for Fe, from 56.2% to 79.6% for Cu, from 68.4% to 78.4% for Ni, from 42.0% to 63.6% for Al and from 64.9% to 86.2% for C cathode. The performance of the palladized Fe foam cathode was tested for degradation of TCE in the presence of nitrates, as another commonly found groundwater species. TCE removal decreased from 99% to 41.2% in presence of 100 mg L(-1) of nitrates due to the competition with TCE for HDC at the cathode. The results indicate that the cathode material affects TCE removal rate while the Pd catalyst significantly enhances cathode activity to degrade TCE via HDC.

  19. Mitigating Voltage Decay of Li-Rich Cathode Material via Increasing Ni Content for Lithium-Ion Batteries.

    PubMed

    Shi, Ji-Lei; Zhang, Jie-Nan; He, Min; Zhang, Xu-Dong; Yin, Ya-Xia; Li, Hong; Guo, Yu-Guo; Gu, Lin; Wan, Li-Jun

    2016-08-10

    Li-rich layered materials have been considered as the most promising cathode materials for future high-energy-density lithium-ion batteries. However, they suffer from severe voltage decay upon cycling, which hinders their further commercialization. Here, we report a Li-rich layered material 0.5Li2MnO3·0.5LiNi0.8Co0.1Mn0.1O2 with high nickel content, which exhibits much slower voltage decay during long-term cycling compared to conventional Li-rich materials. The voltage decay after 200 cycles is 201 mV. Combining in situ X-ray diffraction (XRD), ex situ XRD, ex situ X-ray photoelectron spectroscopy, and scanning transmission electron microscopy, we demonstrate that nickel ions act as stabilizing ions to inhibit the Jahn-Teller effect of active Mn(3+) ions, improving d-p hybridization and supporting the layered structure as a pillar. In addition, nickel ions can migrate between the transition-metal layer and the interlayer, thus avoiding the formation of spinel-like structures and consequently mitigating the voltage decay. Our results provide a simple and effective avenue for developing Li-rich layered materials with mitigated voltage decay and a long lifespan, thereby promoting their further application in lithium-ion batteries with high energy density.

  20. Part I: Electronic and ionic transport properties of the ordered and disordered LiNi0.5Mn1.5O4 spinel cathode

    NASA Astrophysics Data System (ADS)

    Amin, Ruhul; Belharouk, Ilias

    2017-04-01

    Here, we report on the electronic and ionic conductivity and diffusivity of the ordered (P4332) and disordered (Fd 3 bar m) LiNi0.5Mn1.5O4 spinel material, which have been determined by using ion and electron blocking cell configurations as a function of lithium concentration and temperature. The disordered phase exhibits about fifteen-time higher electronic conductivity than the ordered phase at room temperature in the lithiated state. Upon delithiation, the electronic conductivity of the ordered LiNi0.5Mn1.5O4 phase increases and reaches the same levels observed for the disordered phase. The ionic conductivity and diffusivity of LiNi0.5Mn1.5O4, in the ordered and disordered forms, are in the range of ∼1 × 10-9 S/cm and ∼5 × 10-9 cm2/s, respectively. Both phases exhibit similar activation energies for the ionic conductivity and diffusivity, i.e. 0.70 ± 0.2eV and 0.74 ± 0.2eV, respectively. It can be concluded from the obtained results that the electrochemical performance of LiNi0.5Mn1.5O4, whether ordered or disordered, is limited by lithium transport, but is fast enough to allow charge/discharge of micron-scale particles at practical C-rates.

  1. Spectroscopic studies of cathode materials for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Totir, Dana Alexa

    2000-10-01

    Structural changes that occur during electrochemical cycling of lithium-ion battery cathode materials have been investigated using in situ spectroscopic techniques. A new method was developed for the preparation of carbon and binder free cathodes utilizing powder materials of interest for commercial batteries. The extraordinary quality of the cyclic voltammetric curves recorded for this type of electrodes during the in situ measurements allows direct correlations to be made between the state of charge of the material and its structural and electronic characteristics. LiCoO2, LiMn2O4 and LiCo0.15Ni 0.85O2 electrodes were evaluated using cycling voltammetry and the mean diffusion coefficient for Li-ions in the lattice (DLi) was calculated for LiMn2O4. LiMn2O4 electrodes prepared by this technique have been studied in situ using Mn K-edge XAS. Data analysis for the species formed at different potentials indicated a contraction of the lattice associated with the increase in the oxidation state of manganese. In situ Raman spectra of particles of LiMn2O 4, and LiCoO2 embedded in Au and also of KS-44 graphite and carbon microfibers MCF28 embedded in thermally annealed Ni have been recorded as a function of the applied potential. Fe K-edge XAFS of pyrite electrodes in a Li/PEO(LiClO4)/FeS 2 cell and S K-edge XANES measurements of a FeS2 electrode in a non-aqueous electrolyte have been acquired as a function of the state of charge. The studies have clearly evidenced the formation of metallic Fe and Li2S as intermediates after 4 e- discharge and the formation of Li2FeS2 after 2 e- recharge. While Fe K-edge studies have indicated that there is no change in the Fe environment and oxidation state upon 4 e- recharge, the results obtained from S K-edge studies are inconclusive for this stage. Finally, in situ Co K-edge XAFS data were obtained for the first time during the electrochemical cycling of electrodeposited Co(OH) 2 films in alkaline solutions. The results support

  2. Development of Cathode Materials for Low Temperature SOFCs

    SciTech Connect

    Simner, Steve P. ); Bonnett, Jeff F. ); Canfield, Nathan L. ); Meinhardt, Kerry D. ); Shelton, Jayne P.; Sprenkle, Vince L. ); Stevenson, Jeffry W. )

    2002-11-21

    This paper details some of the recent efforts towards SOFC cathode development conducted at Pacific Northwest National Laboratory (PNNL). It is widely established that the performance of low-temperature SOFCs is highly dependent on cathode polarization losses, which must be minimized to optimize the SOFC power densities.

  3. Organotrisulfide: A High Capacity Cathode Material for Rechargeable Lithium Batteries.

    PubMed

    Wu, Min; Cui, Yi; Bhargav, Amruth; Losovyj, Yaroslav; Siegel, Amanda; Agarwal, Mangilal; Ma, Ying; Fu, Yongzhu

    2016-08-16

    An organotrisulfide (RSSSR, R is an organic group) has three sulfur atoms which could be involved in multi-electron reduction reactions; therefore it is a promising electrode material for batteries. Herein, we use dimethyl trisulfide (DMTS) as a model compound to study its redox reactions in rechargeable lithium batteries. With the aid of XRD, XPS, and GC-MS analysis, we confirm DMTS could undergo almost a 4 e(-) reduction process in a complete discharge to 1.0 V. The discharge products are primarily LiSCH3 and Li2 S. The lithium cell with DMTS catholyte delivers an initial specific capacity of 720 mAh g(-1) DMTS and retains 82 % of the capacity over 50 cycles at C/10 rate. When the electrolyte/DMTS ratio is 3:1 mL g(-1) , the reversible specific energy for the cell including electrolyte can be 229 Wh kg(-1) . This study shows organotrisulfide is a promising high-capacity cathode material for high-energy rechargeable lithium batteries. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Cobalt-manganese-based spinels as multifunctional materials that unify catalytic water oxidation and oxygen reduction reactions.

    PubMed

    Menezes, Prashanth W; Indra, Arindam; Sahraie, Nastaran Ranjbar; Bergmann, Arno; Strasser, Peter; Driess, Matthias

    2015-01-01

    Recently, there has been much interest in the design and development of affordable and highly efficient oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) catalysts that can resolve the pivotal issues that concern solar fuels, fuel cells, and rechargeable metal-air batteries. Here we present the synthesis and application of porous CoMn2 O4 and MnCo2 O4 spinel microspheres as highly efficient multifunctional catalysts that unify the electrochemical OER with oxidant-driven and photocatalytic water oxidation as well as the ORR. The porous materials were prepared by the thermal degradation of the respective carbonate precursors at 400 °C. The as-prepared spinels display excellent performances in electrochemical OER for the cubic MnCo2 O4 phase in comparison to the tetragonal CoMn2 O4 material in an alkaline medium. Moreover, the oxidant-driven and photocatalytic water oxidations were performed and they exhibited a similar trend in activity to that of the electrochemical OER. Remarkably, the situation is reversed in ORR catalysis, that is, the oxygen reduction activity and stability of the tetragonal CoMn2 O4 catalyst outperformed that of cubic MnCo2 O4 and rivals that of benchmark Pt catalysts. The superior catalytic performance and the remarkable stability of the unifying materials are attributed to their unique porous and robust microspherical morphology and the intrinsic structural features of the spinels. Moreover, the facile access to these high-performance materials enables a reliable and cost-effective production on a large scale for industrial applications.

  5. Oxide Fiber Cathode Materials for Rechargeable Lithium Cells

    NASA Technical Reports Server (NTRS)

    Rice, Catherine E.; Welker, Mark F.

    2008-01-01

    LiCoO2 and LiNiO2 fibers have been investigated as alternatives to LiCoO2 and LiNiO2 powders used as lithium-intercalation compounds in cathodes of rechargeable lithium-ion electrochemical cells. In making such a cathode, LiCoO2 or LiNiO2 powder is mixed with a binder [e.g., poly(vinylidene fluoride)] and an electrically conductive additive (usually carbon) and the mixture is pressed to form a disk. The binder and conductive additive contribute weight and volume, reducing the specific energy and energy density, respectively. In contrast, LiCoO2 or LiNiO2 fibers can be pressed and sintered to form a cathode, without need for a binder or a conductive additive. The inter-grain contacts of the fibers are stronger and have fewer defects than do those of powder particles. These characteristics translate to increased flexibility and greater resilience on cycling and, consequently, to reduced loss of capacity from cycle to cycle. Moreover, in comparison with a powder-based cathode, a fiber-based cathode is expected to exhibit significantly greater ionic and electronic conduction along the axes of the fibers. Results of preliminary charge/discharge-cycling tests suggest that energy densities of LiCoO2- and LiNiO2-fiber cathodes are approximately double those of the corresponding powder-based cathodes.

  6. Graphene wrapped ordered LiNi0.5Mn1.5O4 nanorods as promising cathode material for lithium-ion batteries

    PubMed Central

    Tang, Xiao; Jan, S. Savut; Qian, Yanyan; Xia, Hui; Ni, Jiangfeng; Savilov, Serguei V.; Aldoshin, Serguei M.

    2015-01-01

    LiNi0.5Mn1.5O4 nanorods wrapped with graphene nanosheets have been prepared and investigated as high energy and high power cathode material for lithium-ion batteries. The structural characterization by X-ray diffraction, Raman spectroscopy, and Fourier transform infrared spectroscopy indicates the LiNi0.5Mn1.5O4 nanorods prepared from β-MnO2 nanowires have ordered spinel structure with P4332 space group. The morphological characterization by scanning electron microscopy and transmission electron microscopy reveals that the LiNi0.5Mn1.5O4 nanorods of 100–200 nm in diameter are well dispersed and wrapped in the graphene nanosheets for the composite. Benefiting from the highly conductive matrix provided by graphene nanosheets and one-dimensional nanostructure of the ordered spinel, the composite electrode exhibits superior rate capability and cycling stability. As a result, the LiNi0.5Mn1.5O4-graphene composite electrode delivers reversible capacities of 127.6 and 80.8 mAh g−1 at 0.1 and 10 C, respectively, and shows 94% capacity retention after 200 cycles at 1 C, greatly outperforming the bare LiNi0.5Mn1.5O4 nanorod cathode. The outstanding performance of the LiNi0.5Mn1.5O4-graphene composite makes it promising as cathode material for developing high energy and high power lithium-ion batteries. PMID:26148558

  7. Graphene wrapped ordered LiNi0.5Mn1.5O4 nanorods as promising cathode material for lithium-ion batteries.

    PubMed

    Tang, Xiao; Jan, S Savut; Qian, Yanyan; Xia, Hui; Ni, Jiangfeng; Savilov, Serguei V; Aldoshin, Serguei M

    2015-07-07

    LiNi0.5Mn1.5O4 nanorods wrapped with graphene nanosheets have been prepared and investigated as high energy and high power cathode material for lithium-ion batteries. The structural characterization by X-ray diffraction, Raman spectroscopy, and Fourier transform infrared spectroscopy indicates the LiNi0.5Mn1.5O4 nanorods prepared from β-MnO2 nanowires have ordered spinel structure with P4332 space group. The morphological characterization by scanning electron microscopy and transmission electron microscopy reveals that the LiNi0.5Mn1.5O4 nanorods of 100-200 nm in diameter are well dispersed and wrapped in the graphene nanosheets for the composite. Benefiting from the highly conductive matrix provided by graphene nanosheets and one-dimensional nanostructure of the ordered spinel, the composite electrode exhibits superior rate capability and cycling stability. As a result, the LiNi0.5Mn1.5O4-graphene composite electrode delivers reversible capacities of 127.6 and 80.8 mAh g(-1) at 0.1 and 10 C, respectively, and shows 94% capacity retention after 200 cycles at 1 C, greatly outperforming the bare LiNi0.5Mn1.5O4 nanorod cathode. The outstanding performance of the LiNi0.5Mn1.5O4-graphene composite makes it promising as cathode material for developing high energy and high power lithium-ion batteries.

  8. Challenges and approaches for high-voltage spinel lithium-ion batteries.

    PubMed

    Kim, Jung-Hyun; Pieczonka, Nicholas P W; Yang, Li

    2014-07-21

    Lithium-ion (Li-ion) batteries have been developed for electric vehicle (EV) applications, owing to their high energy density. Recent research and development efforts have been devoted to finding the next generation of cathode materials for Li-ion batteries to extend the driving distance of EVs and lower their cost. LiNi(0.5)Mn(1.5)O(4) (LNMO) high-voltage spinel is a promising candidate for a next-generation cathode material based on its high operating voltage (4.75 V vs. Li), potentially low material cost, and excellent rate capability. Over the last decade, much research effort has focused on achieving a fundamental understanding of the structure-property relationship in LNMO materials. Recent studies, however, demonstrated that the most critical barrier for the commercialization of high-voltage spinel Li-ion batteries is electrolyte decomposition and concurrent degradative reactions at electrode/electrolyte interfaces, which results in poor cycle life for LNMO/graphite full cells. Despite scattered reports addressing these processes in high-voltage spinel full cells, they have not been consolidated into a systematic review article. With this perspective, emphasis is placed herein on describing the challenges and the various approaches to mitigate electrolyte decomposition and other degradative reactions in high-voltage spinel cathodes in full cells.

  9. The Impact of Cathode Material and Shape on Current Density in an Aluminum Electrolysis Cell

    NASA Astrophysics Data System (ADS)

    Song, Yang; Peng, Jianping; Di, Yuezhong; Wang, Yaowu; Li, Baokuan; Feng, Naixiang

    2016-02-01

    A finite element model was developed to determine the impact of cathode material and shape on current density in an aluminum electrolysis cell. For the cathode material, results show that increased electrical resistivity leads to a higher cathode voltage drop; however, the horizontal current is reduced in the metal. The horizontal current magnitude for six different cathode materials in decreasing order is graphitized, semi-graphitized, full graphitic, 50% anthracite (50% artificial graphite), 70% anthracite (30% artificial graphite), 100% anthracite. The modified cathode shapes with an inclined cathode surface, higher collector bar and cylindrical protrusions are intended to improve horizontal current and flow resistance. Compared to a traditional cathode, modified collector bar sizes of 70 mm × 230 mm and 80 mm × 270 mm can reduce horizontal current density component Jx by 10% and 19%, respectively, due to better conductivity of the steel. The horizontal current in the metal decreases with increase of cathode inclination. The peak value of Jx can be approximately reduced by 20% for a 2° change in inclination. Cylindrical protrusions lead to local horizontal current increase on their tops, but the average current is less affected and the molten metal is effectively slowed down.

  10. High-Current Cold Cathode Employing Diamond and Related Materials

    SciTech Connect

    Hirshfield, Jay L.

    2014-10-22

    The essence of this project was for diamond films to be deposited on cold cathodes to improve their emission properties. Films with varying morphology, composition, and size of the crystals were deposited and the emission properties of the cathodes that utilize such films were studied. The prototype cathodes fabricated by the methods developed during Phase I were tested and evaluated in an actual high-power RF device during Phase II. These high-power tests used the novel active RF pulse compression system and the X-band magnicon test facility at US Naval Research Laboratory. In earlier tests, plasma switches were employed, while tests under this project utilized electron-beam switching. The intense electron beams required in the switches were supplied from cold cathodes embodying diamond films with varying morphology, including uncoated molybdenum cathodes in the preliminary tests. Tests with uncoated molybdenum cathodes produced compressed X-band RF pulses with a peak power of 91 MW, and a maximum power gain of 16.5:1. Tests were also carried out with switches employing diamond coated cathodes. The pulse compressor was based on use of switches employing electron beam triggering to effect mode conversion. In experimental tests, the compressor produced 165 MW in a ~ 20 ns pulse at ~18× power gain and ~ 140 MW at ~ 16× power gain in a 16 ns pulse with a ~ 7 ns flat-top. In these tests, molybdenum blade cathodes with thin diamond coatings demonstrated good reproducible emission uniformity with a 100 kV, 100 ns high voltage pulse. The new compressor does not have the limitations of earlier types of active pulse compressors and can operate at significantly higher electric fields without breakdown.

  11. Temperature-dependent oxygen behavior of LixNi0.5Mn1.5O4 cathode material for lithium battery

    NASA Astrophysics Data System (ADS)

    Choi, Hyun Woo; Kim, Su Jae; Jeong, Myung Yung; Lee, Seongsu; Rim, Young Hoon; Yang, Yong Suk

    2016-11-01

    We have investigated the temperature-dependent oxygen behavior in the lithium battery cathode LixNi0.5Mn1.5O4 (LNMO) materials in the temperature range 30-1000 °C. As the temperature increases, oxygen release occurs and the change of crystal structures from the face centered cubic spinel at 30 °C to other phases follows. The amount of released oxygen and the changed crystalline phases are dependent on Li content and temperature. These phenomena are reversible against temperature in air, but not in vacuum and argon gas environments. This study illustrates the important role of temperature and atmospheric environments in synthesizing the LNMO battery materials.

  12. Synthesis of single-crystalline spinel LiMn2 O4 Nanorods for lithium-ion batteries with high rate capability and long cycle life.

    PubMed

    Xie, Xiuqiang; Su, Dawei; Sun, Bing; Zhang, Jinqiang; Wang, Chengyin; Wang, Guoxiu

    2014-12-15

    The long-standing challenge associated with capacity fading of spinel LiMn2 O4 cathode material for lithium-ion batteries is investigated. Single-crystalline spinel LiMn2 O4 nanorods were successfully synthesized by a template-engaged method. Porous Mn3 O4 nanorods were used as self-sacrificial templates, into which LiOH was infiltrated by a vacuum-assisted impregnation route. When used as cathode materials for lithium-ion batteries, the spinel LiMn2 O4 nanorods exhibited superior long cycle life owing to the one-dimensional nanorod structure, single-crystallinity, and Li-rich effect. LiMn2 O4 nanorods retained 95.6 % of the initial capacity after 1000 cycles at 3C rate. In particular, the nanorod morphology of the spinel LiMn2 O4 was well-preserved after a long-term cycling, suggesting the ultrahigh structural stability of the single crystalline spinel LiMn2 O4 nanorods. This result shows the promising applications of single-crystalline spinel LiMn2 O4 nanorods as cathode materials for lithium-ion batteries with high rate capability and long cycle life.

  13. Investigating local degradation and thermal stability of charged nickel-based cathode materials through real-time electron microscopy.

    PubMed

    Hwang, Sooyeon; Kim, Seung Min; Bak, Seong-Min; Cho, Byung-Won; Chung, Kyung Yoon; Lee, Jeong Yong; Chang, Wonyoung; Stach, Eric A

    2014-09-10

    In this work, we take advantage of in situ transmission electron microscopy (TEM) to investigate thermally induced decomposition of the surface of Li(x)Ni(0.8)Co(0.15)Al(0.05)O2 (NCA) cathode materials that have been subjected to different states of charge (SOC). While uncharged NCA is stable up to 400 °C, significant changes occur in charged NCA with increasing temperature. These include the development of surface porosity and changes in the oxygen K-edge electron energy loss spectra, with pre-edge peaks shifting to higher energy losses. These changes are closely related to O2 gas released from the structure, as well as to phase changes of NCA from the layered structure to the disordered spinel structure, and finally to the rock-salt structure. Although the temperatures where these changes initiate depend strongly on the state of charge, there also exist significant variations among particles with the same state of charge. Notably, when NCA is charged to x = 0.33 (the charge state that is the practical upper limit voltage in most applications), the surfaces of some particles undergo morphological and oxygen K-edge changes even at temperatures below 100 °C, a temperature that electronic devices containing lithium ion batteries (LIB) can possibly see during normal operation. Those particles that experience these changes are likely to be extremely unstable and may trigger thermal runaway at much lower temperatures than would be usually expected. These results demonstrate that in situ heating experiments are a unique tool not only to study the general thermal behavior of cathode materials but also to explore particle-to-particle variations, which are sometimes of critical importance in understanding the performance of the overall system.

  14. Hexagonal NiS nanobelts as advanced cathode materials for rechargeable Al-ion batteries.

    PubMed

    Yu, Zhijing; Kang, Zepeng; Hu, Zongqian; Lu, Jianhong; Zhou, Zhigang; Jiao, Shuqiang

    2016-08-16

    Hexagonal NiS nanobelts served as novel cathode materials for rechargeable Al-ion batteries based on an AlCl3/[EMIm]Cl ionic liquid electrolyte system. The nano-banded structure of the materials can facilitate the electrolyte immersion and enhance Al(3+) diffusion. The hexagonal NiS nanobelt based cathodes exhibit high storage capacity, good cyclability and low overpotential.

  15. Recovery of cathode materials and Al from spent lithium-ion batteries by ultrasonic cleaning.

    PubMed

    He, Li-Po; Sun, Shu-Ying; Song, Xing-Fu; Yu, Jian-Guo

    2015-12-01

    Cathode materials are difficult to separate from Al-foil substrates during the recycling of spent lithium-ion batteries (LIBs), because of the strong bonding force present. In this study, ultrasonic cleaning was used to separate and recycle these cathode materials. The mechanism of separation was ascribed to the dissolution of polyvinylidene fluoride (PVDF) and the cavitation caused by ultrasound. Based on this mechanism, the key parameters affecting the peel-off efficiency of cathode materials from Al foil was identified as solvent nature, temperature, ultrasonic power, and ultrasonic time. The peel-off efficiency of cathode materials achieved ∼ 99% under the optimized conditions of N-methyl-2-pyrrolidone (NMP) cleaning fluid, 70°C process temperature, 240 W ultrasonic power, and 90 min of ultrasonication. The cathode materials separated from Al foil displayed a low agglomeration degree, which is beneficial to the subsequent leaching process. Finally, a new, environmentally-sound process was proposed to efficiently recycle cathode materials and Al from spent LIBs, consisting of manual dismantling, ultrasonic cleaning, and picking.

  16. Surface Modification of Li1.2Ni0.13Mn0.54Co0.13O2 by Hydrazine Vapor as Cathode Material for Lithium-Ion Batteries.

    PubMed

    Zhang, Jie; Lei, Zhihong; Wang, Jiulin; NuLi, Yanna; Yang, Jun

    2015-07-29

    An artificial interface is successfully prepared on the surface of the layered lithium-rich cathode material Li1.2Ni0.13Mn0.54Co0.12O2 via treating it with hydrazine vapor, followed by an annealing process. The inductively coupled plasma-atomic emission spectrometry (ICP) results indicate that lithium ions are leached out from the surface of Li1.2Ni0.13Mn0.54Co0.12O2 by the hydrazine vapor. A lithium-deficiency-driven transformation from layered to spinel at the particle surface happens in the annealing process, which is proved by the results of X-ray diffraction (XRD) and high-resolution transmission electron microscope (HRTEM). It is also found that the content of the spinel phase increases at higher annealing temperature, and an internal structural evolution from Li1-xM2O4-type spinel to M3O4-type spinel takes place simultaneously. Compared to the pristine Li1.2Ni0.13Mn0.54Co0.12O2, the surface-modified sample annealed at 300 °C delivers a larger initial discharge capacity of 295.6 mA h g(-1) with a Coulombic efficiency of 89.5% and a better rate performance (191.7 mA h g(-1) at 400 mA g(-1)).

  17. Phase control of Mn-based spinel films via pulsed laser deposition

    SciTech Connect

    Feng, Zhenxing; Chen, Xiao; Fister, Timothy T.; Bedzyk, Michael J.; Fenter, Paul

    2016-07-06

    Phase transformations in battery cathode materials during electrochemical-insertion reactions lead to capacity fading and low cycle life. One solution is to keep the same phase of cathode materials during cation insertion-extraction processes. Here, we demonstrate a novel strategy to control the phase and composition of Mn-based spinel oxides for magnesium-ion battery applications through the growth of thin films on lattice-matched substrates using pulsed laser deposition. Materials at two extreme conditions are considered: fully discharged cathode MgMn2O4 and fully charged cathode Mn2O4. The tetragonal MgMn2O4 (MMO) phase is obtained on MgAl2O4 substrates, while the cubic MMO phase is obtained on MgO substrates. Similarly, growth of the empty Mn2O4 spinel in the cubic phase is obtained on an MgO substrate. These results demonstrate the ability to control separately the phase of spinel thin films (e.g., tetragonal vs. cubic MMO) at nominally fixed composition, and to maintain a fixed (cubic) phase while varying its composition (MgxMn2O4, for x = 0, 1). As a result, this capability provides a novel route to gain insights into the operation of battery electrodes for energy storage applications.

  18. Phase control of Mn-based spinel films via pulsed laser deposition

    SciTech Connect

    Feng, Zhenxing; Chen, Xiao; Fister, Timothy T.; Bedzyk, Michael J.; Fenter, Paul

    2016-07-06

    Phase transformations in battery cathode materials during electrochemical-insertion reactions lead to capacity fading and low cycle life. One solution is to keep the same phase of cathode materials during cation insertion-extraction processes. Here, we demonstrate a novel strategy to control the phase and composition of Mn-based spinel oxides for magnesium-ion battery applications through the growth of thin films on lattice-matched substrates using pulsed laser deposition. Materials at two extreme conditions are considered: fully discharged cathode MgMn2O4 and fully charged cathode Mn2O4. The tetragonal MgMn2O4 (MMO) phase is obtained on MgAl2O4 substrates, while the cubic MMO phase is obtained on MgO substrates. Similarly, growth of the empty Mn2O4 spinel in the cubic phase is obtained on an MgO substrate. These results demonstrate the ability to control separately the phase of spinel thin films (e.g., tetragonal vs. cubic MMO) at nominally fixed composition, and to maintain a fixed (cubic) phase while varying its composition (MgxMn2O4, for x = 0, 1). As a result, this capability provides a novel route to gain insights into the operation of battery electrodes for energy storage applications.

  19. Phase control of Mn-based spinel films via pulsed laser deposition

    DOE PAGES

    Feng, Zhenxing; Chen, Xiao; Fister, Timothy T.; ...

    2016-07-06

    Phase transformations in battery cathode materials during electrochemical-insertion reactions lead to capacity fading and low cycle life. One solution is to keep the same phase of cathode materials during cation insertion-extraction processes. Here, we demonstrate a novel strategy to control the phase and composition of Mn-based spinel oxides for magnesium-ion battery applications through the growth of thin films on lattice-matched substrates using pulsed laser deposition. Materials at two extreme conditions are considered: fully discharged cathode MgMn2O4 and fully charged cathode Mn2O4. The tetragonal MgMn2O4 (MMO) phase is obtained on MgAl2O4 substrates, while the cubic MMO phase is obtained on MgOmore » substrates. Similarly, growth of the empty Mn2O4 spinel in the cubic phase is obtained on an MgO substrate. These results demonstrate the ability to control separately the phase of spinel thin films (e.g., tetragonal vs. cubic MMO) at nominally fixed composition, and to maintain a fixed (cubic) phase while varying its composition (MgxMn2O4, for x = 0, 1). As a result, this capability provides a novel route to gain insights into the operation of battery electrodes for energy storage applications.« less

  20. Phase control of Mn-based spinel films via pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Feng, Zhenxing; Chen, Xiao; Fister, Timothy T.; Bedzyk, Michael J.; Fenter, Paul

    2016-07-01

    Phase transformations in battery cathode materials during electrochemical-insertion reactions lead to capacity fading and low cycle life. One solution is to keep the same phase of cathode materials during cation insertion-extraction processes. Here, we demonstrate a novel strategy to control the phase and composition of Mn-based spinel oxides for magnesium-ion battery applications through the growth of thin films on lattice-matched substrates using pulsed laser deposition. Materials at two extreme conditions are considered: fully discharged cathode MgMn2O4 and fully charged cathode Mn2O4. The tetragonal MgMn2O4 (MMO) phase is obtained on MgAl2O4 substrates, while the cubic MMO phase is obtained on MgO substrates. Similarly, growth of the empty Mn2O4 spinel in the cubic phase is obtained on an MgO substrate. These results demonstrate the ability to control separately the phase of spinel thin films (e.g., tetragonal vs. cubic MMO) at nominally fixed composition, and to maintain a fixed (cubic) phase while varying its composition (MgxMn2O4, for x = 0, 1). This capability provides a novel route to gain insights into the operation of battery electrodes for energy storage applications.

  1. Key strategies for enhancing the cycling stability and rate capacity of LiNi0.5Mn1.5O4 as high-voltage cathode materials for high power lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Yi, Ting-Feng; Mei, Jie; Zhu, Yan-Rong

    2016-06-01

    Spinel LiNi0.5Mn1.5O4 (LNMO) is one of the most promising high voltage cathode materials for future application due to its advantages of large reversible capacity, high thermal stability, low cost, environmental friendliness, and high energy density. LNMO can provide 20% and 30% higher energy density than traditional cathode materials LiCoO2 and LiFePO4, respectively. Unfortunately, LNMO-based batteries with LiPF6-based carbonate electrolytes always suffer from severe capacity deterioration and poor thermostability because of the oxidization of organic carbonate solvents and decomposition of LiPF6, especially at elevated temperatures and water-containing environment. Hence, it is necessary to systematically and comprehensively summarize the progress in understanding and modifying LNMO cathode from various aspects. In this review, the structure, transport properties and different reported possible fading mechanisms of LNMO cathode are first discussed detailedly. And then, the major goal of this review is to highlight new progress in using proposed strategies to improve the cycling stability and rate capacity of LNMO-based batteries, including synthesis, control of special morphologies, element doping and surface coating etc., especially at elevated temperatures. Finally, an insight into the future research and further development of LNMO cathode is discussed.

  2. Improved electrochemical performance of the Cr doped cathode materials for energy storage/conversion devices

    NASA Astrophysics Data System (ADS)

    Sangeeta, Agnihotri, Shruti; Arya, Anil; Sharma, A. L.

    2016-05-01

    Successful synthesis of a nanostructured Cr-doped LiFePO4 cathode material has been prepared by a sol-gel technique followed by a single step thermal treatment at 750° C for 12 hours. As olivine type LiFePO4 has already gained much attention due to its advantages over other cathode materials, doping of metal ion is done in the paper to improve its drawback of lower conductivity. FESEM couples with EDX were done to characterize the morphology and particle size of the materials. LiFe(1-x)CrxPO4 (x=0.1, 0.2, 0.3) materials have average particle size of 30 to 50 nm. EDX analysis confirmed the precursor used and also confirmed the presence of carbon which is in good agreement with chemical analysis result. Electrical conductivity of the prepared cathode materials is estimated of the order of 10-5 Scm-1 by AC impedance analysis. The energy density and power density of the cathode materials is improved drastically after addition of Cr as dopant. The estimated parameters appear at desirable value for use of materials as cathode in energy storage/conversion devices.

  3. Performance analysis of new cathode materials for molten carbonate fuel cells

    NASA Astrophysics Data System (ADS)

    Paoletti, C.; Carewska, M.; Presti, R. Lo; Phail, S. Mc; Simonetti, E.; Zaza, F.

    The slow dissolution of the lithiated nickel oxide cathode represents one of the main causes of performance degradation in molten carbonate fuel cells (MCFC). Two main approaches were studied in ENEA laboratories to overcome this problem: protecting the nickel cathode covering it by a thin layer of a material with a low solubility in molten carbonate and stabilizing the nickel cathode doping it with iron and magnesium. Among several materials, due to its low solubility and good conductivity, lithium cobaltite was chosen to cover the nickel cathode and slow down its dissolution. A nickel electrode covered with a thin layer of lithium cobaltite doped with magnesium, was fabricated by complex sol-gel process. To simplify electrode preparation, no thermal treatments were made after covering to produce lithium cobaltite, and during the cell start-up LiMg 0.05Co 0.95O 2 was obtained in situ. To stabilize the nickel cathode, metal oxides Fe 2O 3 and MgO were chosen as dopant additives to be mixed with NiO powder in a tape-casting process (Mg 0.05Fe 0.01Ni 0.94O). On the prepared materials TGA analysis, morphological analysis by scanning electron microscopy (SEM-EDS) and electrical conductivity measurements were carried out. A conventional nickel cathode, the nickel cathode covered by lithium cobaltite precursors and the nickel cathode stabilized by iron and magnesium oxides were each tested in a 100 cm 2 fuel cell. Polarization curves and internal resistance (iR) measurements were acquired during the cell lifetime (1000 h) and the effect of gas composition variation on the cell performance was studied. From a comparison with the conventional nickel cathode it can be observed that the new materials have similar performance and show a good potential stability during the cell operating time. From the post-test analysis both the nickel cathode covered by lithium cobaltite and the nickel cathode doped with iron and magnesium seem to succeed in reducing nickel dissolution.

  4. On the dispersion of lithium-sulfur battery cathode materials effected by electrostatic and stereo-chemical factors of binders

    NASA Astrophysics Data System (ADS)

    Hong, Xiaoheng; Jin, Jun; Wen, Zhaoyin; Zhang, Sanpei; Wang, Qingsong; Shen, Chen; Rui, Kun

    2016-08-01

    Sodium carboxymethyl cellulose-styrene butadiene rubber (CMC-SBR), sodium alginate (SA) and LA132 are utilized as the polymer binders for the cathodes of Li-S batteries to study their dispersion mechanism on the cathode materials and the consequent influence on the performance of Li-S batteries. Zeta potential tests, differential scanning calorimetry analysis and calculations of the rotational barriers of the links of the polymer chains by General Atomic and Molecular Electronic Structure System (GAMESS) reveal that higher charge densities and better chain flexibility of the binders promise the dispersion of the downsized cathode materials. LA132 is found to have optimal characteristic for dispersing and stabilizing the cathode materials in aqueous environment. The cycling performance and SEM images of the cathodes demonstrate that cathodes with higher dispersion degree achieve higher discharge capacities. The electrochemical impedance spectroscopy (EIS) results further support that better dispersed cathodes have lower impedance resulting from their well established conducting frameworks.

  5. Recent Advances and Prospects of Cathode Materials for Sodium-Ion Batteries.

    PubMed

    Xiang, Xingde; Zhang, Kai; Chen, Jun

    2015-09-23

    Sodium-ion batteries (SIBs) receive significant attention for electrochemical energy storage and conversion owing to their wide availability and the low cost of Na resources. However, SIBs face challenges of low specific energy, short cycling life, and insufficient specific power, owing to the heavy mass and large radius of Na(+) ions. As an important component of SIBs, cathode materials have a significant effect on the SIB electrochemical performance. The most recent advances and prospects of inorganic and organic cathode materials are summarized here. Among current cathode materials, layered transition-metal oxides achieve high specific energies around 600 mW h g(-1) owing to their high specific capacities of 180-220 mA h g(-1) and their moderate operating potentials of 2.7-3.2 V (vs Na(+) /Na). Porous Na3 V2 (PO4 )3 /C nanomaterials exhibit excellent cycling performance with almost 100% retention over 1000 cycles owing to their robust structural framework. Recent emerging cathode materials, such as amorphous NaFePO4 and pteridine derivatives show interesting electrochemical properties and attractive prospects for application in SIBs. Future work should focus on strategies to enhance the overall performance of cathode materials in terms of specific energy, cycling life, and rate capability with cationic doping, anionic substitution, morphology fabrication, and electrolyte matching.

  6. Phase stability of Li-Mn-O oxides as cathode materials for Li-ion batteries: insights from ab initio calculations.

    PubMed

    Longo, R C; Kong, F T; KC, Santosh; Park, M S; Yoon, J; Yeon, D-H; Park, J-H; Doo, S-G; Cho, K

    2014-06-21

    In this work, we present a density-functional theory (DFT) investigation of the phase stability, electrochemical stability and phase transformation mechanisms of the layered and over-lithiated Mn oxides. This study includes the thermodynamic stability of Li and oxygen vacancies, to examine the electrochemical activation mechanisms of these cathode materials. The DFT calculations provide phase diagrams of the Li-Mn-O system in both physical and chemical potential spaces, including the crystals containing vacancies as independent phases. The results show the ranges of electrochemical activity for both layered LiMnO2 and over-lithiated Li2MnO3. By using a thermodynamic model analysis, we found that the required temperature for oxygen evolution and Li vacancy formation is too high to be compatible with any practical synthesis temperature. Using solid-state transition calculations, we have identified the key steps in the phase transition mechanism of the layered LiMnO2 into the spinel phase. The calculated effects of pH on the Li-Mn-O phase stability elucidated the mechanism of Mn(2+) formation from the spinel phase under acidic conditions.

  7. Activated porous carbon wrapped sulfur sub-microparticles as cathode materials for lithium sulfur batteries

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Yan, Y. L.; Ren, B.; Yang, R.; Zhang, W.; Xu, Y. H.

    2017-03-01

    The lithium-sulfur batteries holds a high theoretical capacity and specific energy, which is 4-5 times larger than that of today’s lithium-ion batteries, yet the low sulfur loading and large particles in the cathode greatly offset its advantage in high energy density. In the present paper, a liquid phase deposition method was introduced to synthesize sub-micro sulfur particles, which utilized as cathode materials after composed with activated porous carbon. Compared with common sublimed sulfur cathodes, as-obtained composite cathode shows an enhanced initial discharge capacity from 840.7 mAh/g to 1093 mAh/g at C/10. The reversible specific capacity after 50 cycles increased from 383 mAh/g to 504 mAh/g. The developed method has the advantages of simple process, convenient operation and low cost, and is suitable for the industrial preparation of lithium/sulfur batteries.

  8. Carbyne polysulfide as a novel cathode material for rechargeable magnesium batteries.

    PubMed

    NuLi, Yanna; Chen, Qiang; Wang, Weikun; Wang, Ying; Yang, Jun; Wang, Jiulin

    2014-01-01

    We report the formation of carbyne polysulfide by coheating carbon containing carbyne moieties and elemental sulfur. The product is proved to have a sp2 hybrid carbon skeleton with polysulfide attached on it. The electrochemical performance of carbyne polysulfide as a novel cathode material for rechargeable magnesium batteries is firstly investigated. The material exhibits a high discharge capacity of 327.7 mAh g(-1) at 3.9 mA g(-1). These studies show that carbyne polysulfide is a promising candidate as cathode material for rechargeable Mg batteries if the capacity retention can be significantly improved.

  9. Studies on niobium triselenide cathode material for lithium rechargeable cells

    NASA Technical Reports Server (NTRS)

    Ratnakumar, B. V.; Ni, C. L.; Distefano, S.; Somoano, R. B.; Bankston, C. P.

    1988-01-01

    NbSe3 exhibits superior characteristics such as high capacity, high volumetric and gravimetric energy densities, and high discharge rate capability, as compared to other intercalating cathodes. This paper reports the preparation, characterization, and performance of NbSe3. Several electrochemical techniques, such as cyclic voltammetry, constant-current/constant-potential discharges, dc potentiodynamic scans, ac impedance, and ac voltammetry, have been used to give insight to the mechanisms of intercalation of three lithiums with NbSe3 and also into the rate determining process in the reduction of NbSe3.

  10. Studies on niobium triselenide cathode material for lithium rechargeable cells

    NASA Technical Reports Server (NTRS)

    Ratnakumar, B. V.; Ni, C. L.; Distefano, S.; Somoano, R. B.; Bankston, C. P.

    1988-01-01

    NbSe3 exhibits superior characteristics such as high capacity, high volumetric and gravimetric energy densities, and high discharge rate capability, as compared to other intercalating cathodes. This paper reports the preparation, characterization, and performance of NbSe3. Several electrochemical techniques, such as cyclic voltammetry, constant-current/constant-potential discharges, dc potentiodynamic scans, ac impedance, and ac voltammetry, have been used to give insight to the mechanisms of intercalation of three lithiums with NbSe3 and also into the rate determining process in the reduction of NbSe3.

  11. Cathode and electrolyte materials for solid oxide fuel cells and ion transport membranes

    DOEpatents

    Jacobson, Allan J; Wang, Shuangyan; Kim, Gun Tae

    2014-01-28

    Novel cathode, electrolyte and oxygen separation materials are disclosed that operate at intermediate temperatures for use in solid oxide fuel cells and ion transport membranes based on oxides with perovskite related structures and an ordered arrangement of A site cations. The materials have significantly faster oxygen kinetics than in corresponding disordered perovskites.

  12. Gas evolution behaviors for several cathode materials in lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Kong, Weihe; Li, Hong; Huang, Xuejie; Chen, Liquan

    Several 18650 lithium-ion batteries using LiCoO 2, LiMn 2O 4, and LiFePO 4 as cathode materials were assembled separately. Gas species of these batteries under normal cycling and overcharging to 4.5 and 5.0 V conditions were examined by means of GC-MS method. Under the normal charge and discharge voltage range, it is found that gas components are independent to the cathode materials. C 2H 5F gas was detected in all cases. A formation mechanism is proposed. Under overcharging condition, it is found that the gas components are different and there is a correlation between the C 2H 2 product and the oxidation ability of various delithiated cathode materials.

  13. Cathode material for lithium ion accumulators prepared by screen printing for Smart Textile applications

    NASA Astrophysics Data System (ADS)

    Syrový, T.; Kazda, T.; Syrová, L.; Vondrák, J.; Kubáč, L.; Sedlaříková, M.

    2016-03-01

    The presented study is focused on the development of LiFePO4 based cathode for thin and flexible screen printed secondary lithium based accumulators. An ink formulation was developed for the screen printing technique, which enabled mass production of accumulator's cathode for Smart Label and Smart Textile applications. The screen printed cathode was compared with an electrode prepared by the bar coating technique using an ink formulation based on the standard approach of ink composition. Obtained LiFePO4 cathode layers were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and galvanostatic charge/discharge measurements at different loads. The discharge capacity, capacity retention and stability at a high C rate of the LiFePO4 cathode were improved when Super P and PVDF were replaced by conductive polymers PEDOT:PSS. The achieved capacity during cycling at various C rates was approximately the same at the beginning and at the end, and it was about 151 mAh/g for cycling under 1C. The obtained results of this novelty electrode layer exceed the parameters of several electrode layers based on LiFePO4 published in literature in terms of capacity, cycling stability and overcomes them in terms of simplicity/industrial process ability of cathode layer fabrication and electrode material preparation.

  14. Hollow nanoparticle cathode materials for sodium electrochemical cells and batteries

    DOEpatents

    Shevchenko, Elena; Rajh, Tijana; Johnson, Christopher S.; Koo, Bonil

    2016-07-12

    A cathode comprises, in its discharged state, a layer of hollow .gamma.-Fe.sub.2O.sub.3 nanoparticles disposed between two layers of carbon nanotubes, and preferably including a metallic current collector in contact with one of the layers of carbon nanotubes. Individual particles of the hollow .gamma.-Fe.sub.2O.sub.3 nanoparticles comprise a crystalline shell of .gamma.-Fe.sub.2O.sub.3 including cation vacancies within the crystal structure of the shell (i.e., iron vacancies of anywhere between 3% to 90%, and preferably 44 to 77% of available octahedral iron sites). Sodium ions are intercalated within at least some of the cation vacancies within the crystalline shell of the hollow .gamma.-Fe.sub.2O.sub.3 nanoparticles.

  15. Fabrication and characterization of lithium manganese nickel oxide sputtered thin film cathodes for lithium-ion batteries

    SciTech Connect

    Baggetto, Loic; Unocic, Raymond R; Dudney, Nancy J; Veith, Gabriel M

    2012-01-01

    Li-rich and stoichiometric Li1Mn1.5Ni0.5O4 (LMNO) cathode films have been prepared by magnetron sputtering. Sputtering from a Li stoichiometric target yields Li-rich films composed of spinel, layered and monoclinic phases. Films obtained from a Li deficient target are mostly made of a spinel phase and little layered material. The resulting cathode thin films have good capacity retention and very high rate capability. The reaction mechanism has been investigated by XRD and HRTEM and evidences the reversible formation of a spinel phase, as is also found for the powder samples. The film geometry enables to understand the effect of coatings (ZnO or LiPON). Coating high voltage cathodes reduces the coulombic losses but at the price of rate performance. Nonetheless, these coated sputtered electrode thin films offer a higher rate capability than other LMNO thin films obtained by other physical vapor deposition techniques.

  16. Synthesis, Characterization and Testing of Novel Anode and Cathode Materials for Li-Ion Batteries

    SciTech Connect

    White, Ralph E.; Popov, Branko N.

    2002-10-31

    During this program we have synthesized and characterized several novel cathode and anode materials for application in Li-ion batteries. Novel synthesis routes like chemical doping, electroless deposition and sol-gel method have been used and techniques like impedance, cyclic voltammetry and charge-discharge cycling have been used to characterize these materials. Mathematical models have also been developed to fit the experimental result, thus helping in understanding the mechanisms of these materials.

  17. Theoretical Studies in Enhancing the Efficiency of Cathode and Anode Materials in PEMFC (Proton Exchange Membrane Fuel Cells)

    DTIC Science & Technology

    2011-03-04

    efficiency of cathode and anode materials in PEMFC (Proton Exchange Membrane Fuel Cells) 5a. CONTRACT NUMBER FA23861014012 5b. GRANT NUMBER 5c. PROGRAM...Rev. 8-98) Prescribed by ANSI Std Z39-18 Theoretical studies in enhancing the efficiency of cathode and anode materials in PEMFC (Proton Exchange

  18. Beyond Conventional Cathode Materials for Lithium-ion Batteries and Sodium-ion Batteries Nickel fluoride conversion materials and P2 type Sodium-ion intercalation cathodes

    NASA Astrophysics Data System (ADS)

    Lee, Dae Hoe

    The Li-ion battery is one of the most important rechargeable energy storage devices due to its high energy density, long cycle life, and reliable safety. Although the performances of Li-ion batteries have been improved dramatically, the limit in terms of the energy density still needs to be resolved to meet the growing demands for large-scale mobile devices. Choosing the cathode material is the most pivotal issue in achieving higher energy, since the energy density is directly correlated to the specific capacity of the cathode. Intercalation-based cathode materials have been widely utilized in commercial products; however they yield a limited capacity due to restricted crystallographic sites for Li-ions. In this thesis, the NiF2 and NiO doped NiF2/C conversion materials, which display substantially greater capacities, are intensively studied using various synchrotron X-ray techniques and magnetic measurements. The enhanced electronic conductivity of NiO doped NiF2/C is associated with a significant improvement in the reversible conversion reaction. While bimodal Ni nanoparticles are maintained for NiO doped NiF2/C upon the discharge, for pure NiF2 only smaller nanoparticles remain following the 2nd discharge. Based on the electronic conductivity, it is demonstrated that the size of Ni nanoparticles is associated with the conversion kinetics and consequently the reversibility. Although Li-ion batteries offer the highest energy density among all the secondary batteries, the amount of the reserves and the cost associated with the Li sources are still a concern. In the second part of the thesis, P2 type Na2/3[Ni1/3Mn2/3]O2 is investigated to understand the structural stability in the Na-ion batteries. Significantly improved battery performances are obtained by excluding the phase transformation region. In addition, the structural evolution of the P2-Na0.8[Li0.12Ni0.22Mn0.66]O 2 is tracked by in situ technique and revealed no phase transformation during the cycling. It

  19. Synthesis of Ag@LiFePO4/C composite cathode material by electrodeposition method.

    PubMed

    Fan, Qi; Chen, Yan Feng

    2012-05-01

    Ag@LiFePO4/C particles were prepared by a facile and one-step electrodeposition method. This core-shell structure cathode material has excellent electrochemical performances (both high charge/discharge rates and good cyclability), which can meet the demands of many high power applications.

  20. Anode and cathode materials characterization for a microbial fuel cell in half cell configuration.

    PubMed

    Pant, Deepak; Van Bogaert, Gilbert; Porto-Carrero, Christof; Diels, Ludo; Vanbroekhoven, Karolien

    2011-01-01

    Microbial fuel cells (MFCs) are novel bioelectrochemical devices for spontaneous conversion of biomass into electricity through the metabolic activity of the bacteria. Microbial production of electricity may become an important source of bioenergy in future because MFCs offer the possibility of extracting electric current from a wide range of soluble or dissolved complex organic wastes and renewable biomass. However, the materials used in these devices are still not economic and researchers use different materials as cathode and anode in MFCs. This results in variable performance which is difficult to compare. We tested several commercially available materials for their suitability as anode in an acetate fed MFC. Besides, a novel non-platinized activated carbon (AC) based, gas porous air cathode was also tested. Both the anode and cathode were tested in a half cell configuration. Carbon cloth, graphite cloth and dynamically stable anode (DSA) served as ideal anode material with carbon cloth and graphite mesh reaching the open circuit voltage (OCV) of acetate oxidation (-500 mV vs. Ag/AgCl). The effect of increasing concentration of acetate on anode OCV was also investigated and results showed that on increasing the acetate concentration from 10 mM to 40 mM has no adverse impact on the anodic activity towards electrochemical oxidation of acetate. The AC cathode showed stable current (-1.2 mA/cm2) over a period of 100 days.

  1. Cost and energy demand of producing nickel manganese cobalt cathode material for lithium ion batteries

    DOE PAGES

    Ahmed, Shabbir; Nelson, Paul A.; Gallagher, Kevin G.; ...

    2017-01-05

    The price of the cathode active materials in lithium ion batteries is a key cost driver and thus significantly impacts consumer adoption of devices that utilize large energy storage contents (e.g. electric vehicles). A process model has been developed and used to study the production process of a common lithium-ion cathode material, lithiated nickel manganese cobalt oxide, using the co-precipitation method. The process was simulated for a plant producing 6500 kg day–1. The results indicate that the process will consume approximately 4 kWh kgNMC–1 of energy, 15 L kgNMC–1 of process water, and cost $23 to produce a kg ofmore » Li-NMC333. The calculations were extended to compare the production cost using two co-precipitation reactions (with Na2CO3 and NaOH), and similar cathode active materials such as lithium manganese oxide and lithium nickel cobalt aluminum oxide. Finally, a combination of cost saving opportunities show the possibility to reduce the cost of the cathode material by 19%.« less

  2. Cost and energy demand of producing nickel manganese cobalt cathode material for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Ahmed, Shabbir; Nelson, Paul A.; Gallagher, Kevin G.; Susarla, Naresh; Dees, Dennis W.

    2017-02-01

    The price of the cathode active materials in lithium ion batteries is a key cost driver and thus significantly impacts consumer adoption of devices that utilize large energy storage contents (e.g. electric vehicles). A process model has been developed and used to study the production process of a common lithium-ion cathode material, lithiated nickel manganese cobalt oxide, using the co-precipitation method. The process was simulated for a plant producing 6500 kg day-1. The results indicate that the process will consume approximately 4 kWh kgNMC-1 of energy, 15 L kgNMC-1 of process water, and cost 23 to produce a kg of Li-NMC333. The calculations were extended to compare the production cost using two co-precipitation reactions (with Na2CO3 and NaOH), and similar cathode active materials such as lithium manganese oxide and lithium nickel cobalt aluminum oxide. A combination of cost saving opportunities show the possibility to reduce the cost of the cathode material by 19%.

  3. Structural changes and thermal stability of charged LiNixMnyCozO2 cathode materials studied by combined in situ time-resolved XRD and mass spectroscopy

    DOE PAGES

    Bak, Seong -Min; Hu, Enyuan; Zhou, Yongning; ...

    2014-11-24

    Thermal stability of charged LiNixMnyCozO2 (NMC, with x + y + z = 1, x:y:z = 4:3:3 (NMC433), 5:3:2 (NMC532), 6:2:2 (NMC622), and 8:1:1 (NMC811)) cathode materials is systematically studied using combined in situ time- resolved X-ray diffraction and mass spectroscopy (TR-XRD/MS) techniques upon heating up to 600 °C. The TR-XRD/MS results indicate that the content of Ni, Co, and Mn significantly affects both the structural changes and the oxygen release features during heating: the more Ni and less Co and Mn, the lower the onset temperature of the phase transition (i.e., thermal decomposition) and the larger amount of oxygenmore » release. Interestingly, the NMC532 seems to be the optimized composition to maintain a reasonably good thermal stability, comparable to the low-nickel-content materials (e.g., NMC333 and NMC433), while having a high capacity close to the high-nickel-content materials (e.g., NMC811 and NMC622). The origin of the thermal decomposition of NMC cathode materials was elucidated by the changes in the oxidation states of each transition metal (TM) cations (i.e., Ni, Co, and Mn) and their site preferences during thermal decomposition. It is revealed that Mn ions mainly occupy the 3a octahedral sites of a layered structure (R3¯m) but Co ions prefer to migrate to the 8a tetrahedral sites of a spinel structure (Fd3¯m) during the thermal decomposition. Such element-dependent cation migration plays a very important role in the thermal stability of NMC cathode materials. The reasonably good thermal stability and high capacity characteristics of the NMC532 composition is originated from the well-balanced ratio of nickel content to manganese and cobalt contents. As a result, this systematic study provides insight into the rational design of NMC-based cathode materials with a desired balance between thermal stability and high energy density.« less

  4. The dissolution mechanism of cathodic active materials of spent Zn-Mn batteries in HCl.

    PubMed

    Li, Yunqing; Xi, Guoxi

    2005-12-09

    The cathodic active materials of spent Zn-Mn batteries are complicated. The majority materials that they contain are Mn(OH)(2), Mn(2)O(4), lambda-Mn(2)O(2), ZnMn(2)O(4), Zn(NH(3))(2)Cl(2), [Zn(OH)(2)](4).ZnCl(2), etc. Dissolving these kinds of materials is important to the environmental pollution control and materials recycle. In present paper we investigated the dissolution mechanism of the cathodic active materials in HCl by testing the factors that can influence the dissolution procedure, including temperature, time, and the concentration of HCl and H(2)O(2). Our results showed that both neutralization and oxidation-reduction reactions occurred in the dissolution process, and that H(2)O(2) had a great effect on the dissolution efficiency.

  5. Exceptional performance of a high voltage spinel LiNi0.5Mn1.5O4 cathode in all one dimensional architectures with an anatase TiO2 anode by electrospinning

    NASA Astrophysics Data System (ADS)

    Arun, Nagasubramanian; Aravindan, Vanchiappan; Jayaraman, Sundaramurthy; Shubha, Nageswaran; Ling, Wong Chui; Ramakrishna, Seeram; Madhavi, Srinivasan

    2014-07-01

    We report for the first time the synthesis and extraordinary performance of a high voltage spinel LiNi0.5Mn1.5O4 fiber cathode in all one dimensional (1D) architecture. Structural and morphological features are analyzed by various characterization techniques. Li-insertion/extraction properties are evaluated in a half-cell assembly (Li/LiNi0.5Mn1.5O4) and subsequently in full-cell configuration with an anatase TiO2 fiber anode. In both half- and full-cell assemblies, gelled polyvinylidene fluoride-co-hexafluoropropylene (PVdF-HFP) is used as the separator-cum-electrolyte. All the one dimensional components used for fabricating Li-ion cells are prepared by a simple and scalable electrospinning technique. The full-cell, LiNi0.5Mn1.5O4/gelled PVdF-HFP/TiO2 delivered the reversible capacity of ~102 mA h g-1 at 0.1 C rate with an operating potential of ~2.8 V. Excellent rate capability and stable cycling profiles are noted for such a full-cell assembly with a capacity retention of ~86% after 400 cycles.

  6. Exceptional performance of a high voltage spinel LiNi0.5Mn1.5O4 cathode in all one dimensional architectures with an anatase TiO2 anode by electrospinning.

    PubMed

    Arun, Nagasubramanian; Aravindan, Vanchiappan; Jayaraman, Sundaramurthy; Shubha, Nageswaran; Ling, Wong Chui; Ramakrishna, Seeram; Madhavi, Srinivasan

    2014-08-07

    We report for the first time the synthesis and extraordinary performance of a high voltage spinel LiNi(0.5)Mn(1.5)O4 fiber cathode in all one dimensional (1D) architecture. Structural and morphological features are analyzed by various characterization techniques. Li-insertion/extraction properties are evaluated in a half-cell assembly (Li/LiNi(0.5)Mn(1.5)O4) and subsequently in full-cell configuration with an anatase TiO2 fiber anode. In both half- and full-cell assemblies, gelled polyvinylidene fluoride-co-hexafluoropropylene (PVdF-HFP) is used as the separator-cum-electrolyte. All the one dimensional components used for fabricating Li-ion cells are prepared by a simple and scalable electrospinning technique. The full-cell, LiNi(0.5)Mn(1.5)O4/gelled PVdF-HFP/TiO2 delivered the reversible capacity of ∼ 102 mA h g(-1) at 0.1 C rate with an operating potential of ∼ 2.8 V. Excellent rate capability and stable cycling profiles are noted for such a full-cell assembly with a capacity retention of ∼ 86% after 400 cycles.

  7. Aerospace applications of sodium batteries using novel cathode materials

    NASA Technical Reports Server (NTRS)

    Ratnakumar, B. V.; Di Stefano, S.; Bankston, C. P.

    1989-01-01

    Preliminary fundamental investigations aimed at evaluating sodium metal chloride systems for future aerospace applications are described. Since the sodium metal chloride systems are relatively new, the approach has been to characterize their fundamental properties in order to understand their limitations. To this end, a series of fundamental electrochemical investigations have been carried out, the results of which are reported here. The metal chloride cathodes show high exchange current densities which corroborate their good reversibility in a battery application. The reduction mechanisms appear to be complex and involve multielectron transfer steps and intermediates. Such intermediates in the reaction mechanism have already been identified in the case of FeCl2. Similar mechanisms may be operative in the case of NiCl2. CuCl2, however, exhibits a second relaxation loop in the impedance plot at low frequencies and also a sloping discharge curve, unlike FeCl2 and NiCl2, which may indicate the existence of monovalent copper in the reduction mechanism.

  8. Aerospace applications of sodium batteries using novel cathode materials

    NASA Technical Reports Server (NTRS)

    Ratnakumar, B. V.; Di Stefano, S.; Bankston, C. P.

    1989-01-01

    Preliminary fundamental investigations aimed at evaluating sodium metal chloride systems for future aerospace applications are described. Since the sodium metal chloride systems are relatively new, the approach has been to characterize their fundamental properties in order to understand their limitations. To this end, a series of fundamental electrochemical investigations have been carried out, the results of which are reported here. The metal chloride cathodes show high exchange current densities which corroborate their good reversibility in a battery application. The reduction mechanisms appear to be complex and involve multielectron transfer steps and intermediates. Such intermediates in the reaction mechanism have already been identified in the case of FeCl2. Similar mechanisms may be operative in the case of NiCl2. CuCl2, however, exhibits a second relaxation loop in the impedance plot at low frequencies and also a sloping discharge curve, unlike FeCl2 and NiCl2, which may indicate the existence of monovalent copper in the reduction mechanism.

  9. Rapid synthesis of monodispersed highly porous spinel nickel cobaltite (NiCo{sub 2}O{sub 4}) electrode material for supercapacitors

    SciTech Connect

    Naveen, A. Nirmalesh Selladurai, S.

    2015-06-24

    Monodispersed highly porous spinel nickel cobaltite electrode material was successfully synthesized in a short time using combustion technique. Single phase cubic nature of the spinel nickel cobaltite with average crystallite size of 24 nm was determined from X-ray diffraction study. Functional groups present in the compound were determined from FTIR study and it further confirms the spinel formation. FESEM images reveal the porous nature of the prepared material and uniform size distribution of the particles. Electrochemical evaluation was performed using Cyclic Voltammetry (CV) technique, Chronopotentiometry (CP) and Electrochemical Impedance Spectroscopy (EIS). Results reveal the typical pseudocapacitive behaviour of the material. Maximum capacitance of 754 F/g was calculated at the scan rate of 5 mV/s, high capacitance was due to the unique porous morphology of the electrode. Nyquist plot depicts the low resistance and good electrical conductivity of nickel cobaltite. It has been found that nickel cobaltite prepared by this typical method will be a potential electrode material for supercapcitor application.

  10. Ruthenium dioxide as cathode material for hydrogen evolution in hydroxide and chlorate solutions

    SciTech Connect

    Cornell, A.; Simonsson, D. . Dept. of Applied Electrochemistry and Corrosion Science)

    1993-11-01

    Ruthenium dioxide as electrocatalyst on an activated cathode for chlorate production was investigated with respect to its activity towards hydrogen evolution, hypochlorite reduction, and chlorate reduction, respectively. Investigations were made in the presence, as well as in the absence, of a chromium hydroxide film in 1M NaOH and in typical chlorate electrolyte. Low overvoltages for hydrogen evolution were found and, at technical current densities, an effect of catalyst coating thickness. Commercial DSA electrodes with RuO[sub 2] as the active compound were tested as cathodes and were less active but more stable than the coatings produced by the authors. Hypochlorite and chlorate were reduced in the absence of chromate, chlorate reduction being fast on ruthenium dioxide compared to the other electrode materials and by far the dominating cathodic reaction in chlorate electrolyte without chromate and hypochlorite at 70 C, 3 kA/m[sup 2].

  11. Materials characterization of impregnated W and W-Ir cathodes after oxygen poisoning

    NASA Astrophysics Data System (ADS)

    Polk, James E.; Capece, Angela M.

    2015-05-01

    Electric thrusters use hollow cathodes as the electron source for generating the plasma discharge and for beam neutralization. These cathodes contain porous tungsten emitters impregnated with BaO material to achieve a lower surface work function and are operated with xenon propellant. Oxygen contaminants in the xenon plasma can poison the emitter surface, resulting in a higher work function and increased operating temperature. This could lead directly to cathode failure by preventing discharge ignition or could accelerate evaporation of the BaO material. Exposures over hundreds of hours to very high levels of oxygen can result in increased temperatures, oxidation of the tungsten substrate, and the formation of surface layers of barium tungstates. In this work, we present results of a cathode test in which impregnated tungsten and tungsten-iridium emitters were operated with 100 ppm of oxygen in the xenon plasma for several hundred hours. The chemical and morphological changes were studied using scanning electron microscopy, energy dispersive spectroscopy, and laser profilometry. The results provide strong evidence that high concentrations of oxygen accelerate the formation of tungstate layers in both types of emitters, a phenomenon not inherent to normal cathode operation. Deposits of pure tungsten were observed on the W-Ir emitter, indicating that tungsten is preferentially removed from the surface and transported in the insert plasma. A W-Ir cathode surface will therefore evolve to a pure W composition, eliminating the work function benefit of W-Ir. However, the W-Ir emitter exhibited less erosion and redeposition at the upstream end than the pure W emitter.

  12. Synthesis of Li-Rich Cathode Material with High C-Rate Performance by Reductive Treatment

    NASA Astrophysics Data System (ADS)

    Lim, Sung Nam; Seo, Jung Yoon; Song, Shin Ae; Kim, Ki Young; Park, Seung Bin; Jung, Dae Soo

    2017-01-01

    Li-rich cathode materials have intrinsically poor rate capability along with low electronic conductivity, which remain as unsolved drawbacks limiting their use in applications that require cathode material with layered structures. Here, we prepared surface-modified Li-rich cathode materials to address these drawbacks via reductive treatment. After reductive treatment, we confirmed that these samples feature better electrochemical performance; the reductive treated samples show higher capacity and better capacity retention during cycling compared to samples treated only in air. In particular, the reductive treated samples showed excellent rate capability of 168 mAh g-1 at a current density of 400 mA g-1 compared to 138 mAh g-1 for the air treated sample. We confirmed that reductive treatment reduces the resistance for charge transfer based on electrochemical impedance spectroscopy analysis. We also investigated the effects of reductive treatment on the cathode structure of both samples using x-ray diffraction as well as x-ray photoelectron spectroscopy.

  13. An investigation of anode and cathode materials in photomicrobial fuel cells.

    PubMed

    Schneider, Kenneth; Thorne, Rebecca J; Cameron, Petra J

    2016-02-28

    Photomicrobial fuel cells (p-MFCs) are devices that use photosynthetic organisms (such as cyanobacteria or algae) to turn light energy into electrical energy. In a p-MFC, the anode accepts electrons from microorganisms that are either growing directly on the anode surface (biofilm) or are free floating in solution (planktonic). The nature of both the anode and cathode material is critical for device efficiency. An ideal anode is biocompatible and facilitates direct electron transfer from the microorganisms, with no need for an electron mediator. For a p-MFC, there is the additional requirement that the anode should not prevent light from perfusing through the photosynthetic cells. The cathode should facilitate the rapid reaction of protons and oxygen to form water so as not to rate limit the device. In this paper, we first review the range of anode and cathode materials currently used in p-MFCs. We then present our own data comparing cathode materials in a p-MFC and our first results using porous ceramic anodes in a mediator-free p-MFC.

  14. Synthesis of Li-Rich Cathode Material with High C-Rate Performance by Reductive Treatment

    NASA Astrophysics Data System (ADS)

    Lim, Sung Nam; Seo, Jung Yoon; Song, Shin Ae; Kim, Ki Young; Park, Seung Bin; Jung, Dae Soo

    2017-03-01

    Li-rich cathode materials have intrinsically poor rate capability along with low electronic conductivity, which remain as unsolved drawbacks limiting their use in applications that require cathode material with layered structures. Here, we prepared surface-modified Li-rich cathode materials to address these drawbacks via reductive treatment. After reductive treatment, we confirmed that these samples feature better electrochemical performance; the reductive treated samples show higher capacity and better capacity retention during cycling compared to samples treated only in air. In particular, the reductive treated samples showed excellent rate capability of 168 mAh g-1 at a current density of 400 mA g-1 compared to 138 mAh g-1 for the air treated sample. We confirmed that reductive treatment reduces the resistance for charge transfer based on electrochemical impedance spectroscopy analysis. We also investigated the effects of reductive treatment on the cathode structure of both samples using x-ray diffraction as well as x-ray photoelectron spectroscopy.

  15. Mitigating Voltage Fade in Cathode Materials by Improving the Atomic Level Uniformity of Elemental Distribution

    SciTech Connect

    Zheng, Jianming; Gu, Meng; Genc, Arda; Xiao, Jie; Xu, Pinghong; Chen, Xilin; Zhu, Zihua; Zhao, Wenbo; Pullan, Lee; Wang, Chong M.; Zhang, Jiguang

    2014-04-07

    Li-rich and Mn-rich (LMR) layered structured materials are very promising cathodes for high-energy lithium-ion batteries. However, their fundamental structure and voltage fading mechanisms are far from being well understood. Here we report the first evidence on the reduced voltage and energy fade of LMR cathode by improving the atomic level spatial distribution of the chemical species. LMR cathode (Li[Li0.2Ni0.2M0.6]O2) prepared by co-precipitation and sol-gel methods are dominated by R-3m phase and show significant Ni-segregation at the surface of the particles. They exhibit large voltage-fade and fast capacity degradation. In contrast, LMR cathode prepared by hydrothermal assisted method is dominated by C2/m phase and minimal Ni-segregation. It also demonstrates much smaller voltage-fade and excellent capacity retention. The fundamental correlation between the atomic level spatial distribution of the chemical species and the functional stability of the materials found in this work also guide the design of other functional materials with enhanced stabilities.

  16. Electron microscopy characterization of Li-based cathode materials for battery applications

    NASA Astrophysics Data System (ADS)

    Phillips, Patrick; Klie, Robert

    2014-03-01

    The role of aberration-corrected scanning transmission electron microscopy (STEM) in materials characterization is examined with respect to Li-based cathode materials for battery applications. STEM-based methods are quickly becoming the most promising characterization tools for these materials, owed largely to the wide-range of techniques available on advanced STEM instruments, including the direct imaging of both heavy and light elements, and both energy-dispersive X-ray (EDX) and electron energy loss (EEL) spectroscopies. The current talk with focus on structural and chemical characterization of a Li-based cathode material, both in a pristine and irradiated state. Focus will remain on the nucleation of structural transitions, while also characterizing relevant parameters such as the manganese valence and oxygen presence. Various imaging modes, including high/low angle annular dark field (H/LAADF) and annular bright field (ABF), in conjunction with EELS, will be used extensively for this analysis.

  17. Chemically synthesized boron carbon oxynitride as a new cold cathode material

    NASA Astrophysics Data System (ADS)

    Banerjee, Diptonil; Maity, Supratim; Chattopadhyay, K. K.

    2015-11-01

    Synthesis of boron carbon oxynitride (BCNO) nanosheets at different temperature from amorphous to crystalline regime has been reported. The synthesis was done by a simple molten salt process using sodium borohydride and urea as precursors. Transmission electron microscopic study confirms the formation of sheet-like structure of the as-synthesized material. The performances of the as-synthesized BCNO nanosheets as cold cathode materials have been studied for the first time in the high vacuum electron field emission set up. It has been seen that the material gives considerable field emission current with turn on field as low as 2.95 V/μm with good stability and thus a new cold cathode material can be postulated.

  18. Phospho-olivines as cathode materials for lithium ion battery: trends on microwave synthesis

    NASA Astrophysics Data System (ADS)

    Alarcón-Suesca, C. E.; Nilges, T.

    2014-04-01

    In recently years, scientific research has been focused on finding new sources of efficient energy storage and lithium batteries are one of the most outstanding alternatives. Nowadays, investigation on cathode materials constitute one of the key factors of lithium rechargeable batteries studies. Recently, oxides with olivine structures has triggered the battery field, due to its excellent electrochemical properties, crystal stability, energy density, power capacity and are not expensive. However, the demand and development of more enhanced cathode materials can be achieved by the use of sophisticated synthetic methods. The purpose of this article is to provide a perspective to the materials community on the opportunities and limitations of nanostructured materials by highlighting examples in synthesis, fundamental studies and applications on microwave synthesis as novel route to obtain high voltage phospho-olivines.

  19. Superior hybrid cathode material containing lithium-excess layered material and graphene for lithium-ion batteries.

    PubMed

    Jiang, Ke-Cheng; Wu, Xing-Long; Yin, Ya-Xia; Lee, Jong-Sook; Kim, Jaekook; Guo, Yu-Guo

    2012-09-26

    Graphene-wrapped lithium-excess layered hybrid materials (Li(2)MnO(3)·LiMO(2), M = Mn, Ni, Co, hereafter abbreviated as LMNCO) have been synthesized and investigated as cathode materials for lithium-ion batteries. Cyclic voltammetry measurement shows a significant reduction of the reaction overpotential in benefit of the graphene conducting framework. The electrochemical impedance spectroscopy results reveal that the graphene can greatly reduce the cell resistance, especially the charge transfer resistance. Our investigation demonstrates that the graphene conducting framework can efficiently alleviate the polarization of pristine LMNCO material leading to an outstanding enhancement in cell performance and cycling stability. The superior electrochemical properties support the fine hybrid structure design by enwrapping active materials in graphene nanosheets for high-capacity and high-rate cathode materials.

  20. Cu2Se with facile synthesis as a cathode material for rechargeable sodium batteries.

    PubMed

    Yue, Ji-Li; Sun, Qian; Fu, Zheng-Wen

    2013-07-04

    A Cu2Se electrode on a copper grid substrate has been directly fabricated by a facile post-selenized method and tested as a positive material for sodium ion batteries. Cu2Se exhibits large reversible capacities (about 250 mA h g(-1)), good cyclic stabilities and low polarization. These results indicate that Cu2Se is a promising candidate as a cathode material for sodium ion batteries.

  1. Cathode and insulator materials for a 30 kW arcjet thruster

    NASA Technical Reports Server (NTRS)

    Sokolowski, Witold; O'Donnell, Tim; Deininger, William

    1989-01-01

    This paper describes past experience with 30 kW arcjet engines, emphasizing the operational parameters pertinent to the selection of new/alternate erosion-resistant materials to enhance lifetime. Mechanisms of mass loss from the electrodes and insulators are suggested, and ways of identifying potential processes for controlling cathode erosion and insulator degradation are proposed. The limitations of present materials used in critical arcjet thruster components are described. An outline is given of the criteria and the figure of merit on which the selection of candidate materials can be based. Potentially useful new/alternate materials are listed based on available thermophysical and other material properties.

  2. Full microwave synthesis of advanced Li-rich manganese based cathode material for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Shi, Shaojun; Zhang, Saisai; Wu, Zhijun; Wang, Ting; Zong, Jianbo; Zhao, Mengxi; Yang, Gang

    2017-01-01

    In technologically important Li-rich layered cathode materials, the synthesis time is a critical determinant to overcome the practical difficulties. Normal technology costs at least one day or even more to obtain final Li-rich cathode material. Full microwave synthesis is performed here to obtain final Li1.2Mn0.56Ni0.16Co0.08O2 within 60 min with high time-efficiency and power economization. The as-prepared Li-rich oxides keep the spherical hierarchical structure of the precursor. Compared to the same material obtained by traditional calcination, it exhibits well-formed layered structure with higher ordered ion arrangement. X-ray photoelectron spectroscopy (XPS) indicates that microwave assisted heating contributes to a more ordered and stable surface with desired Mn, Co, Ni element states and less impurity. Thus, the as-prepared material reveals remarkable electrochemical property with high discharge capacity of 159.3 mAh g-1 at high current density of 2000 mA g-1. And 88.6% specific capacity is remained after 300 cycles at such high current density. Furthermore, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic intermittent titration technique (GITT) are carried out to overall investigate and estimate the material. It is concluded that such full microwave synthesis is really promising as one of the dominant way to obtain Li-rich layered cathode material for applications.

  3. Intercalation and Push-Out Process with Spinel-to-Rocksalt Transition on Mg Insertion into Spinel Oxides in Magnesium Batteries.

    PubMed

    Okamoto, Shinya; Ichitsubo, Tetsu; Kawaguchi, Tomoya; Kumagai, Yu; Oba, Fumiyasu; Yagi, Shunsuke; Shimokawa, Kohei; Goto, Natsumi; Doi, Takayuki; Matsubara, Eiichiro

    2015-08-01

    On the basis of the similarity between spinel and rocksalt structures, it is shown that some spinel oxides (e.g., MgCo2O4, etc) can be cathode materials for Mg rechargeable batteries around 150 °C. The Mg insertion into spinel lattices occurs via "intercalation and push-out" process to form a rocksalt phase in the spinel mother phase. For example, by utilizing the valence change from Co(III) to Co(II) in MgCo2O4, Mg insertion occurs at a considerably high potential of about 2.9 V vs. Mg(2+)/Mg, and similarly it occurs around 2.3 V vs. Mg(2+)/Mg with the valence change from Mn(III) to Mn(II) in MgMn2O4, being comparable to the ab initio calculation. The feasibility of Mg insertion would depend on the phase stability of the counterpart rocksalt XO of MgO in Mg2X2O4 or MgX3O4 (X = Co, Fe, Mn, and Cr). In addition, the normal spinel MgMn2O4 and MgCr2O4 can be demagnesiated to some extent owing to the robust host structure of Mg1-xX2O4, where the Mg extraction/insertion potentials for MgMn2O4 and MgCr2O4 are both about 3.4 V vs. Mg(2+)/Mg. Especially, the former "intercalation and push-out" process would provide a safe and stable design of cathode materials for polyvalent cations.

  4. Spinel materials for Li-ion batteries: new insights obtained by operando neutron and synchrotron X-ray diffraction.

    PubMed

    Bianchini, Matteo; Fauth, François; Suard, Emmanuelle; Leriche, Jean Bernard; Masquelier, Christian; Croguennec, Laurence

    2015-12-01

    In the last few decades Li-ion batteries changed the way we store energy, becoming a key element of our everyday life. Their continuous improvement is tightly bound to the understanding of lithium (de)intercalation phenomena in electrode materials. Here we address the use of operando diffraction techniques to understand these mechanisms. We focus on powerful probes such as neutrons and synchrotron X-ray radiation, which have become increasingly familiar to the electrochemical community. After discussing the general benefits (and drawbacks) of these characterization techniques and the work of customization required to adapt standard electrochemical cells to an operando diffraction experiment, we highlight several very recent results. We concentrate on important electrode materials such as the spinels Li1 + xMn2 - xO4 (0 ≤ x ≤ 0.10) and LiNi0.4Mn1.6O4. Thorough investigations led by operando neutron powder diffraction demonstrated that neutrons are highly sensitive to structural parameters that cannot be captured by other means (for example, atomic Debye-Waller factors and lithium site occupancy). Synchrotron radiation X-ray powder diffraction reveals how LiMn2O4 is subject to irreversibility upon the first electrochemical cycle, resulting in severe Bragg peak broadening. Even more interestingly, we show for the first time an ordering scheme of the elusive composition Li0.5Mn2O4, through the coexistence of Mn(3+):Mn(4+) 1:3 cation ordering and lithium/vacancy ordering. More accurately written as Li0.5Mn(3+)0.5Mn(4+)1.5O4, this intermediate phase loses the Fd\\overline 3m symmetry, to be correctly described in the P213 space group.

  5. Innovative application of ionic liquid to separate Al and cathode materials from spent high-power lithium-ion batteries.

    PubMed

    Zeng, Xianlai; Li, Jinhui

    2014-04-30

    Because of the increasing number of electric vehicles, there is an urgent need for effective recycling technologies to recapture the significant amount of valuable metals contained in spent lithium-ion batteries (LiBs). Previous studies have indicated, however, that Al and cathode materials were quite difficult to separate due to the strong binding force supplied by the polyvinylidene fluoride (PVDF), which was employed to bind cathode materials and Al foil. This research devoted to seek a new method of melting the PVDF binder with heated ionic liquid (IL) to separate Al foil and cathode materials from the spent high-power LiBs. Theoretical analysis based on Fourier's law was adopted to determine the heat transfer mechanism of cathode material and to examine the relationship between heating temperature and retention time. All the experimental and theoretic results show that peel-off rate of cathode materials from Al foil could reach 99% when major process parameters were controlled at 180°C heating temperature, 300 rpm agitator rotation, and 25 min retention time. The results further imply that the application of IL for recycling Al foil and cathode materials from spent high-power LiBs is highly efficient, regardless of the application source of the LiBs or the types of cathode material. This study endeavors to make a contribution to an environmentally sound and economically viable solution to the challenge of spent LiB recycling. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. High energy cathode material for long-life and safe lithium batteries.

    SciTech Connect

    Sun, Y.-K.; Myung, S.-T.; Park, B.-C.; Prakash, J.; Belharouak, I.; Amine, K.; Chemical Sciences and Engineering Division; Hanyang Univ.; Iwate Univ.; Illinois Inst. of Tech.

    2009-04-01

    Layered lithium nickel-rich oxides, Li[Ni{sub 1-x}M{sub x}]O{sub 2} (M=metal), have attracted significant interest as the cathode material for rechargeable lithium batteries owing to their high capacity, excellent rate capability and low cost. However, their low thermal-abuse tolerance and poor cycle life, especially at elevated temperature, prohibit their use in practical batteries. Here, we report on a concentration-gradient cathode material for rechargeable lithium batteries based on a layered lithium nickel cobalt manganese oxide. In this material, each particle has a central bulk that is rich in Ni and a Mn-rich outer layer with decreasing Ni concentration and increasing Mn and Co concentrations as the surface is approached. The former provides high capacity, whereas the latter improves the thermal stability. A half cell using our concentration-gradient cathode material achieved a high capacity of 209 mA h g{sup -1} and retained 96% of this capacity after 50 charge-discharge cycles under an aggressive test profile (55 C between 3.0 and 4.4 V). Our concentration-gradient material also showed superior performance in thermal-abuse tests compared with the bulk composition Li[Ni{sub 0.8}Co{sub 0.1}Mn{sub 0.1}]O{sub 2} used as reference. These results suggest that our cathode material could enable production of batteries that meet the demanding performance and safety requirements of plug-in hybrid electric vehicles.

  7. Synthesis and investigation of novel cathode materials for sodium ion batteries

    NASA Astrophysics Data System (ADS)

    Sawicki, Monica

    Environmental pollution and eventual depletion of fossil fuels and lithium has increased the need for research towards alternative electrical energy storage systems. In this context, research in sodium ion batteries (NIBs) has become more prevalent since the price in lithium has increased due to its demand and reserve location. Sodium is an abundant resource that is low cost, and safe; plus its chemical properties are similar to that of Li which makes the transition into using Na chemistry for ion battery systems feasible. In this study, we report the effects of processing conditions on the electrochemical properties of Na-ion batteries made of the NaCrO2 cathode. NaCrO2 is synthesized via solid state reactions. The as-synthesized powder is then subjected to high-energy ball milling under different conditions which reduces particle size drastically and causes significant degradation of the specific capacity for NaCrO2. X-ray diffraction reveals that lattice distortion has taken place during high-energy ball milling and in turn affects the electrochemical performance of the cathode material. This study shows that a balance between reducing particle size and maintaining the layered structure is essential to obtain high specific capacity for the NaCrO2 cathode. In light of the requirements for grid scale energy storage: ultra-long cycle life (> 20,000 cycles and calendar life of 15 to 20 years), high round trip efficiency (> 90%), low cost, sufficient power capability, and safety; the need for a suitable cathode materials with excellent capacity retention such as Na2MnFe(CN)6 and K2MnFe(CN)6 will be investigated. Prussian blue (A[FeIIIFeII (CN)6]•xH2O, A=Na+ or K+ ) and its analogues have been investigated as an alkali ion host for use as a cathode material. Their structure (FCC) provides large ionic channels along the direction enabling facile insertion and extraction of alkali ions. This material is also capable of more than one Na ion insertion per unit formula

  8. Secondary cell with orthorhombic alkali metal/manganese oxide phase active cathode material

    DOEpatents

    Doeff, Marca M.; Peng, Marcus Y.; Ma, Yanping; Visco, Steven J.; DeJonghe, Lutgard C.

    1996-01-01

    An alkali metal manganese oxide secondary cell is disclosed which can provide a high rate of discharge, good cycling capabilities, good stability of the cathode material, high specific energy (energy per unit of weight) and high energy density (energy per unit volume). The active material in the anode is an alkali metal and the active material in the cathode comprises an orthorhombic alkali metal manganese oxide which undergoes intercalation and deintercalation without a change in phase, resulting in a substantially linear change in voltage with change in the state of charge of the cell. The active material in the cathode is an orthorhombic structure having the formula M.sub.x Z.sub.y Mn.sub.(1-y) O.sub.2, where M is an alkali metal; Z is a metal capable of substituting for manganese in the orthorhombic structure such as iron, cobalt or titanium; x ranges from about 0.2 in the fully charged state to about 0.75 in the fully discharged state, and y ranges from 0 to 60 atomic %. Preferably, the cell is constructed with a solid electrolyte, but a liquid or gelatinous electrolyte may also be used in the cell.

  9. Secondary cell with orthorhombic alkali metal/manganese oxide phase active cathode material

    DOEpatents

    Doeff, M.M.; Peng, M.Y.; Ma, Y.; Visco, S.J.; DeJonghe, L.C.

    1996-09-24

    An alkali metal manganese oxide secondary cell is disclosed which can provide a high rate of discharge, good cycling capabilities, good stability of the cathode material, high specific energy (energy per unit of weight) and high energy density (energy per unit volume). The active material in the anode is an alkali metal and the active material in the cathode comprises an orthorhombic alkali metal manganese oxide which undergoes intercalation and deintercalation without a change in phase, resulting in a substantially linear change in voltage with change in the state of charge of the cell. The active material in the cathode is an orthorhombic structure having the formula M{sub x}Z{sub y}Mn{sub (1{minus}y)}O{sub 2}, where M is an alkali metal; Z is a metal capable of substituting for manganese in the orthorhombic structure such as iron, cobalt or titanium; x ranges from about 0.2 in the fully charged state to about 0.75 in the fully discharged state, and y ranges from 0 to 60 atomic %. Preferably, the cell is constructed with a solid electrolyte, but a liquid or gelatinous electrolyte may also be used in the cell. 11 figs.

  10. Design of fast ion conducting cathode materials for grid-scale sodium-ion batteries.

    PubMed

    Wong, Lee Loong; Chen, Haomin; Adams, Stefan

    2017-03-15

    The obvious cost advantage as well as attractive electrochemical properties, including excellent cycling stability and the potential of high rate performance, make sodium-ion batteries prime candidates in the race to technically and commercially enable large-scale electrochemical energy storage. In this work, we apply our bond valence site energy modelling method to further the understanding of rate capabilities of a wide range of potential insertion-type sodium-ion battery cathode materials. We demonstrate how a stretched exponential function permits us to systematically quantify the rate performance, which in turn reveals guidelines for the design of novel sodium-ion battery chemistries suitable for high power, grid-scale applications. Starting from a diffusion relaxation model, we establish a semi-quantitative prediction of the rate-performance of half-cells from the structure of the cathode material that factors in dimensionality of Na(+) ion migration pathways, the height of the migration barriers and the crystallite size of the active material. With the help of selected examples, we also illustrate the respective roles of unoccupied low energy sites within the pathway and temperature towards the overall rate capability of insertion-type cathode materials.

  11. Anatase as a cathode material in lithium-organic electrolyte rechargeable batteries

    NASA Astrophysics Data System (ADS)

    Bonino, F.; Busani, L.; Lazzari, M.; Manstretta, M.; Rivolta, B.; Scrosati, B.

    1981-07-01

    Preliminary results of a study of the rechargable behavior of anatase TiO2 as a cathode material in secondary lithium-organic electrolyte batteries are reported. Measurements of operating characteristics were performed in electrochemical cells comprised of a lithium disk, glass wool separator disks soaked with a LiClO4-propylene carbonate solution and a pellet of either anatase or rutile as the positive material. The cells are found to exhibit an open circuit voltage between 2.80 and 2.90 V at room temperature for anatase and about 2.50 for rutile, corresponding to a cathodic utilization for anatase close to 60 percent. Polarization tests using a lithium reference electrode with anatase indicate an increase in the reversibility of the electrode as the test progressed, with polarization cycles in Li(0.2)TiO2 showing a practical absence of hysteresis. A maximum recharge efficiency in the first cycle was found to correspond to compositions of a Li/TiO2 mole ratio between 0.2 and 0.4. In extended cycling tests of material of optimal composition, indications of cell deterioration appeared progressively from the 30th cycle, due to lithium dendrite formation; when lithium dendrite effects are limited, cells based on anatase are found to maintain stable values of the discharge voltage for over 120 cycles. Results thus confirm the potential of anatase as a cathode material in lithium secondary batteries.

  12. Development of Boride Composite Materials for Cold Cathode Devices

    DTIC Science & Technology

    1981-05-01

    22 7. Diagram of the Induction Heating Facilities .. .. .....24 8. Typical Pellet After RF Heating...technique in an RF induction furnace. Pellets of the eu- tectic composition available from the literature were melted as well as pellets of a composition...com- pounds with the metals and metal oxides . Pure boron is silvery gray in color. In order to avoid reactions with Other materials at high tempera

  13. Unveiling the Role of CeO2 Atomic Layer Deposition Coatings on LiMn2O4 Cathode Materials: An Experimental and Theoretical Study.

    PubMed

    Sarkar, Susmita; Patel, Rajankumar L; Liang, Xinhua; Park, Jonghyun

    2017-09-13

    An atomic layer deposition (ALD) coating on active materials of a lithium ion battery is a more effective strategy for improving battery performance than other coating technologies. However, substantial uncertainty still remains about the underlying physics and role of the ALD coating in improving battery performance. Although improvement in the stability and capacity of CeO2 thin film coated particles for batteries has been reported, a detailed and accurate description of the mechanism has not been provided. We have developed a multiphysics-based model that takes into consideration stress mechanics, diffusion of lithium ion, and dissolution of transition-metal ions of spinel LiMn2O4 cathode. The model analyzes how different coating thicknesses affect diffusion-induced stress generation and, ultimately, crack propagation. Experimentally measured diffusivity and dissolution rates were incorporated into the model to account for a trade-off between delayed transport and prevention of side reactions. Along with experimental results, density functional theory results are used to explain how a change in volume, due to dissolution of active material, can affect battery performance. The predicted behavior from the model is well-matched with experimental results obtained on coated and uncoated LiMn2O4-Li foil cells. The proposed approach and explanations will serve as important guidelines for thin film coating strategies for various battery materials.

  14. Bare-tether cathodic contact through thermionic emission by low-work-function materials

    SciTech Connect

    Chen Xin; Sanmartin, J. R.

    2012-07-15

    A new material, C12A7:e{sup -} electride, which might present a work function as low as 0.6 eV and moderately high temperature stability, was recently proposed as coating for floating bare tethers. Arising from heating under space operation, current is emitted by thermionic emission along a thus coated cathodic segment. A preliminary study on the space-charge-limited (SCL) double layer in front of the cathodic segment is presented using Langmuir's SCL electron current between cylindrical electrodes and orbital-motion-limited ion-collection sheath. A detailed calculation of current and bias profiles along the entire tether length is carried out with ohmic effects and the transition from SCL to full Richardson-Dushman emission included. Analysis shows that in the simplest drag mode, under typical orbital and tether conditions, thermionic emission leads to a short cathodic section and may eliminate the need for an active cathodic device and its corresponding gas feed requirements and power subsystem, which results in a truly 'propellant-less' tether system for such basic applications as de-orbiting low earth orbit satellites.

  15. Commercial materials as cathode for hydrogen production in microbial electrolysis cell.

    PubMed

    Farhangi, Sara; Ebrahimi, Sirous; Niasar, Mojtaba Shariati

    2014-10-01

    The use of commercial electrodes as cathodes in a single-chamber microbial electrolysis cell has been investigated. The cell was operated in sequencing batch mode and the performance of the electrodes was compared with carbon cloth containing 0.5 mg Pt cm(-2). Overall H2 recovery [Formula: see text] was 66.7 ± 1.4, 58.7 ± 1.1 and 55.5 ± 1.5 % for Pt/CC, Ni and Ti mesh electrodes, respectively. Columbic efficiencies of the three cathodes were in the same range (74.8 ± 1.5, 77.6 ± 1.7 and 75.7 ± 1.2 % for Pt/CC, Ni and Ti mesh electrodes, respectively). A similar performance for the three cathodes under near-neutral pH and ambient temperature was obtained. The commercial electrodes are much cheaper than carbon cloth containing Pt. Low cost and good performance of these electrodes suggest they are suitable cathode materials for large scale application.

  16. Designing and Thermal Analysis of Safe Lithium Ion Cathode Materials for High Energy Applications

    NASA Astrophysics Data System (ADS)

    Hu, Enyuan

    Safety is one of the most critical issues facing lithium-ion battery application in vehicles. Addressing this issue requires the integration of several aspects, especially the material chemistry and the battery thermal management. First, thermal stability investigation was carried out on an attractive high energy density material LiNi0.5Mn1.5O4. New findings on the thermal-stability and thermal-decomposition-pathways related to the oxygen-release are discovered for the high-voltage spinel Li xNi0.5Mn1.5O4 (LNMO) with ordered (o-) and disordered (d-) structures at fully delithiated (charged) state using a combination of in situ time-resolved x-ray diffraction (TR-XRD) coupled with mass spectroscopy (MS) and x-ray absorption spectroscopy (XAS). Both fully charged o--LixNi0.5Mn1.5O 4 and d-LixNi0.5Mn1.5O 4 start oxygen-releasing structural changes at temperatures below 300 °C, which is in sharp contrast to the good thermal stability of the 4V-spinel LixMn2O4 with no oxygen being released up to 375 °C. This is mainly caused by the presence of Ni4+ in LNMO, which undergoes dramatic reduction during the thermal decomposition. In addition, charged o-LNMO shows better thermal stability than the d-LNMO counterpart, due to the Ni/Mn ordering and smaller amount of the rock-salt impurity phase in o-LNMO. Newly identified two thermal-decomposition-pathways from the initial LixNi0.5Mn1.5O 4 spinel to the final NiMn2O4-type spinel structure with and without the intermediate phases (NiMnO3 and alpha-Mn 2O3) are found to play key roles in thermal stability and oxygen release of LNMO during thermal decomposition. In addressing the safety issue associated with LNMO, Fe is selected to partially substitute Ni and Mn simultaneously utilizing the electrochemical activity and structure-stabilizing high spin Fe3+. The synthesized LiNi1/3Mn4/3Fe1/3O4 showed superior thermal stability and satisfactory electrochemical performance. At charged state, it is able to withstand the temperature as

  17. Electrocatalysis paradigm for protection of cathode materials in high-voltage lithium-ion batteries

    SciTech Connect

    Shkrob, Ilya A.; Abraham, Daniel P.

    2016-07-06

    A new mechanistic framework is suggested to account for the protective action of certain electrolyte additives on high-voltage positive electrode (cathode) materials. The mechanism involves inactivation of catalytically active centers on the electrode active materials through fragmentation reactions involving molecules at its surface. The cathode protection additives oxidize before the solvent and serve as sacrificial inhibitors of the catalytic centers. Without the additive, the surface oxidation of the solvent (like solvent oxidation in the bulk) yields H loss radicals and releases the proton that can combine with anions forming corrosive acids. This proton-release reaction is demonstrated experimentally for boronate additives. Specific radical reactions for the latter additives on the electrode surface are suggested. Furthermore, the same approach can be used to rationalize the protective action of other additives and account for various observations regarding their performance.

  18. Electrocatalysis paradigm for protection of cathode materials in high-voltage lithium-ion batteries

    SciTech Connect

    Shkrob, Ilya A.; Abraham, Daniel P.

    2016-07-06

    A new mechanistic framework is suggested to account for the protective action of certain electrolyte additives on high-voltage positive electrode (cathode) materials. The mechanism involves inactivation of catalytically active centers on the electrode active materials through fragmentation reactions involving molecules at its surface. The cathode protection additives oxidize before the solvent and serve as sacrificial inhibitors of the catalytic centers. Without the additive, the surface oxidation of the solvent (like solvent oxidation in the bulk) yields H loss radicals and releases the proton that can combine with anions forming corrosive acids. This proton-release reaction is demonstrated experimentally for boronate additives. Specific radical reactions for the latter additives on the electrode surface are suggested. Furthermore, the same approach can be used to rationalize the protective action of other additives and account for various observations regarding their performance.

  19. Graphene Modified LiFePO4 Cathode Materials for High Power Lithium ion Batteries

    SciTech Connect

    Zhou, X.; Wang, F.; Zhu, Y.; Liu, Z.

    2011-01-24

    Graphene-modified LiFePO{sub 4} composite has been developed as a Li-ion battery cathode material with excellent high-rate capability and cycling stability. The composite was prepared with LiFePO{sub 4} nanoparticles and graphene oxide nanosheets by spray-drying and annealing processes. The LiFePO{sub 4} primary nanoparticles embedded in micro-sized spherical secondary particles were wrapped homogeneously and loosely with a graphene 3D network. Such a special nanostructure facilitated electron migration throughout the secondary particles, while the presence of abundant voids between the LiFePO{sub 4} nanoparticles and graphene sheets was beneficial for Li{sup +} diffusion. The composite cathode material could deliver a capacity of 70 mAh g{sup -1} at 60C discharge rate and showed a capacity decay rate of <15% when cycled under 10C charging and 20C discharging for 1000 times.

  20. Fabrication of LiF/Fe/Graphene nanocomposites as cathode material for lithium-ion batteries.

    PubMed

    Ma, Ruguang; Dong, Yucheng; Xi, Liujiang; Yang, Shiliu; Lu, Zhouguang; Chung, Chiyuen

    2013-02-01

    Homogeneous LiF/Fe/Graphene nanocomposites as cathode material for lithium ion batteries have been synthesized for the first time by a facile two-step strategy, which not only avoids the use of highly corrosive reagents and expensive precursors but also fully takes advantage of the excellent electronic conductivity of graphene. The capacity remains higher than 150 mA h g(-1) after 180 cylces, indicating high reversible capacity and stable cyclability. The ex situ XRD and HRTEM investigations on the cycled LiF/Fe/G nanocomposites confirm the formation of FeF(x) and the coexistence of LiF and FeF(x) at the charged state. Therefore, the heterostructure nanocomposites of LiF/Fe/Graphene with nano-LiF and ultrafine Fe homogeneously anchored on graphene sheets could open up a novel avenue for the application of iron fluorides as high-performance cathode materials for lithium-ion batteries.

  1. Electron-deficient anthraquinone derivatives as cathodic material for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Takeda, Takashi; Taniki, Ryosuke; Masuda, Asuna; Honma, Itaru; Akutagawa, Tomoyuki

    2016-10-01

    We studied the electronic and structural properties of electron-deficient anthraquinone (AQ) derivatives, Me4N4AQ and TCNAQ, and investigated their charge-discharge properties in lithium ion batteries along with those of AQ. Cyclic voltammogram, X-ray structure analysis and theoretical calculations revealed that these three acceptors have different features, such as different electron-accepting properties with different reduction processes and lithium coordination abilities, and different packing arrangements with different intermolecular interactions. These differences greatly affect the charge-discharge properties of lithium ion batteries that use these compounds as cathode materials. Among these compounds, Me4N4AQ showed a high charge/discharge voltage (2.9-2.5 V) with high cyclability (>65% of the theoretical capacity after 30 cycles; no decrease after 15 cycles). These results provide insight into more in-depth design principles for lithium ion batteries using AQ derivatives as cathodic materials.

  2. Electrocatalysis paradigm for protection of cathode materials in high-voltage lithium-ion batteries

    DOE PAGES

    Shkrob, Ilya A.; Abraham, Daniel P.

    2016-07-06

    A new mechanistic framework is suggested to account for the protective action of certain electrolyte additives on high-voltage positive electrode (cathode) materials. The mechanism involves inactivation of catalytically active centers on the electrode active materials through fragmentation reactions involving molecules at its surface. The cathode protection additives oxidize before the solvent and serve as sacrificial inhibitors of the catalytic centers. Without the additive, the surface oxidation of the solvent (like solvent oxidation in the bulk) yields H loss radicals and releases the proton that can combine with anions forming corrosive acids. This proton-release reaction is demonstrated experimentally for boronate additives.more » Specific radical reactions for the latter additives on the electrode surface are suggested. Furthermore, the same approach can be used to rationalize the protective action of other additives and account for various observations regarding their performance.« less

  3. Studies of sulfur-based cathode materials for rechargeable lithium batteries

    NASA Astrophysics Data System (ADS)

    Wu, Min

    Developing alternative cathodes with high capacity is critical for the next generation rechargeable batteries to meet the ever-increasing desires of global energy storage market. This thesis is focused on two sulfur-based cathode materials ranging from inorganic lithium sulfide to organotrisulfide. For lithium sulfide cathode, we developed a nano-Li2S/MWCNT paper electrode through solution filtration method, which involved a low temperature of 100 °C. The Li2S nanocrystals with a size less than 10 nm were formed uniformly in the pores of carbon paper network. These electrodes show an unprecedented low overpotential (0.1 V) in the first charges, also show high discharge capacities, good rate capability, and excellent cycling performance. This superior electrochemical performance makes them promising for use with lithium metal-free anodes in rechargeable Li-S batteries for practical applications. For organotrisulfide cathode, we use a small organotrisulfide compound, e.g. dimethyl trisulfide, to be a high capacity and high specific energy organosulfide cathode material for rechargeable lithium batteries. Based on XRD, XPS, SEM, and GC-MS analysis, we investigated the cell reaction mechanism. The redox reaction of DMTS is a 4e- process and the major discharge products are LiSCH3 and Li2S. The following cell reaction becomes quite complicated, apart from the major product DMTS, the high order organic polysulfide dimethyl tetrasulfide (DMTtS) and low order organic polysulfide dimethyl disulfide (DMDS) are also formed and charged/discharged in the following cycles. With a LiNO3 containing ether-based electrolyte, DMTS cell delivers an initial discharge capacity of 720 mAh g -1 and retains 74% of the initial capacity over 70 cycles with high DMTS loading of 6.7 mg cm-2 at C/10 rate. When the DMTS loading is increased to 11.3 mg cm -2, the specific energy is 1025 Wh kg -1 for the active materials (DMTS and lithium) and the specific energy is 229 Wh kg-1 for the cell

  4. Chemical compatibility study of melilite-type gallate solid electrolyte with different cathode materials

    SciTech Connect

    Mancini, Alessandro; Felice, Valeria; Natali Sora, Isabella; Malavasi, Lorenzo; Tealdi, Cristina

    2014-05-01

    Chemical reactivity between cathodes and electrolytes is a crucial issue for long term SOFCs stability and performances. In this study, chemical reactivity between selected cathodic materials and the ionic conducting melilite La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25} has been extensively investigated by X-ray powder diffraction in a wide temperature range (up to 1573 K). Perovskite-type La{sub 0.8}Sr{sub 0.2}MnO{sub 3−d} and La{sub 0.8}Sr{sub 0.2}Fe{sub 0.8}Cu{sub 0.2}O{sub 3−d} and K{sub 2}NiF{sub 4}-type La{sub 2}NiO{sub 4+d} were selected as cathode materials. The results of this study allow identifying the most suitable electrode material to be used in combination with the melilite-type gallate electrolyte and set the basis for future work on this novel system. - Graphical abstract: Chemical reactivity between cathodes and electrolytes is a crucial issue for long term SOFCs stability and performances. In this study, chemical reactivity between selected cathodic materials and the ionic conducting melilite La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25} has been extensively investigated by means of X-ray powder diffraction. - Highlights: • Chemical compatibility between melilite-type gallate and cathodes for SOFCs up to 1573 K. • No reactivity observed between La{sub 0.8}Sr{sub 0.2}Fe{sub 0.8}Cu{sub 0.2}O{sub 3−d} and La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25}. • Reactivity observed between La{sub 0.80}Sr{sub 0.20}MnO{sub 3−d} and La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25}. • Significant reactivity observed between La{sub 2}NiO{sub 4+d} and La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25}.

  5. Insights into the structural effects of layered cathode materials for high voltage sodium-ion batteries

    DOE PAGES

    Xu, Gui -Liang; Amine, Rachid; Xu, Yue -Feng; ...

    2017-06-08

    Cathode materials are critical to the energy density, power density and safety of sodium-ion batteries (SIBs). Herein, we performed a comprehensive study to elucidate and exemplify the interplay mechanism between phase structures, interfacial microstrain and electrochemical properties of layered-structured NaxNi1/3Co1/3Mn1/3O2 cathode materials for high voltage SIBs. The electrochemical test results showed that NaxNi1/3Co1/3Mn1/3O2 with an intergrowth P2/O3/O1 structure demonstrates better electrochemical performance and better thermal stability than NaxNi1/3Co1/3Mn1/3O2 with P2/O3 binary-phase integration and NaxNi1/3Co1/3Mn1/3O2 where only the P phase is dominant. This result is caused by the distinct interfacial microstrain development during the synthesis and cycling of the P2/O3/O1 phase.more » In operando high energy X-ray diffraction further revealed that the intergrowth P2/O1/O3 cathode can inhibit the irreversible P2–O2 phase transformation and simultaneously improve the structure stability of the O3 and O1 phases during cycling. Here, we believe that interfacial microstrain can serve as an indispensable bridge to guide future design and synthesis of high performance SIB cathode materials and other high energy battery materials.« less

  6. Sulfur-carbon nanocomposites and their application as cathode materials in lithium-sulfur batteries

    DOEpatents

    Liang, Chengdu; Dudney, Nancy J.; Howe, Jane Y.

    2017-08-01

    The invention is directed in a first aspect to a sulfur-carbon composite material comprising: (i) a bimodal porous carbon component containing therein a first mode of pores which are mesopores, and a second mode of pores which are micropores; and (ii) elemental sulfur contained in at least a portion of said micropores. The invention is also directed to the aforesaid sulfur-carbon composite as a layer on a current collector material; a lithium ion battery containing the sulfur-carbon composite in a cathode therein; as well as a method for preparing the sulfur-composite material.

  7. Low-threshold field emission in planar cathodes with nanocarbon materials

    NASA Astrophysics Data System (ADS)

    Zhigalov, V.; Petukhov, V.; Emelianov, A.; Timoshenkov, V.; Chaplygin, Yu.; Pavlov, A.; Shamanaev, A.

    2016-12-01

    Nanocarbon materials are of great interest as field emission cathodes due to their low threshold voltage. In this work current-voltage characteristics of nanocarbon electrodes were studied. Low-threshold emission was found in planar samples where field enhancement is negligible (<10). Electron work function values, calculated by Fowler-Nordheim theory, are anomalous low (<1 eV) and come into collision with directly measured work function values in fabricated planar samples (4.1-4.4 eV). Non-applicability of Fowler-Nordheim theory for the nanocarbon materials was confirmed. The reasons of low-threshold emission in nanocarbon materials are discussed.

  8. Sulfur-carbon nanocomposites and their application as cathode materials in lithium-sulfur batteries

    DOEpatents

    Liang, Chengdu; Dudney, Nancy J; Howe, Jane Y

    2015-05-05

    The invention is directed in a first aspect to a sulfur-carbon composite material comprising: (i) a bimodal porous carbon component containing therein a first mode of pores which are mesopores, and a second mode of pores which are micropores; and (ii) elemental sulfur contained in at least a portion of said micropores. The invention is also directed to the aforesaid sulfur-carbon composite as a layer on a current collector material; a lithium ion battery containing the sulfur-carbon composite in a cathode therein; as well as a method for preparing the sulfur-composite material.

  9. Layered cathode materials for lithium ion rechargeable batteries

    DOEpatents

    Kang, Sun-Ho; Amine, Khalil

    2007-04-17

    A number of materials with the composition Li.sub.1+xNi.sub..alpha.Mn.sub..beta.Co.sub..gamma.M'.sub..delta.O.sub.2-- zF.sub.z (M'=Mg,Zn,Al,Ga,B,Zr,Ti) for use with rechargeable batteries, wherein x is between about 0 and 0.3, .alpha. is between about 0.2 and 0.6, .beta. is between about 0.2 and 0.6, .gamma. is between about 0 and 0.3, .delta. is between about 0 and 0.15, and z is between about 0 and 0.2. Adding the above metal and fluorine dopants affects capacity, impedance, and stability of the layered oxide structure during electrochemical cycling.

  10. Comparison of Nonprecious Metal Cathode Materials for Methane Production by Electromethanogenesis

    PubMed Central

    2014-01-01

    In methanogenic microbial electrolysis cells (MMCs), CO2 is reduced to methane using a methanogenic biofilm on the cathode by either direct electron transfer or evolved hydrogen. To optimize methane generation, we examined several cathode materials: plain graphite blocks, graphite blocks coated with carbon black or carbon black containing metals (platinum, stainless steel or nickel) or insoluble minerals (ferrihydrite, magnetite, iron sulfide, or molybdenum disulfide), and carbon fiber brushes. Assuming a stoichiometric ratio of hydrogen (abiotic):methane (biotic) of 4:1, methane production with platinum could be explained solely by hydrogen production. For most other materials, however, abiotic hydrogen production rates were insufficient to explain methane production. At −600 mV, platinum on carbon black had the highest abiotic hydrogen gas formation rate (1600 ± 200 nmol cm–3 d–1) and the highest biotic methane production rate (250 ± 90 nmol cm–3 d–1). At −550 mV, plain graphite (76 nmol cm–3 d–1) performed similarly to platinum (73 nmol cm–3 d–1). Coulombic recoveries, based on the measured current and evolved gas, were initially greater than 100% for all materials except platinum, suggesting that cathodic corrosion also contributed to electromethanogenic gas production. PMID:24741468

  11. Theoretical evaluation of high-energy lithium metal phosphate cathode materials in Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Howard, Wilmont F.; Spotnitz, Robert M.

    Lithium metal phosphates (olivines) are emerging as long-lived, safe cathode materials in Li-ion batteries. Nano-LiFePO 4 already appears in high-power applications, and LiMnPO 4 development is underway. Current and emerging Fe- and Mn-based intercalants, however, are low-energy producers compared to Ni and Co compounds. LiNiPO 4, a high voltage olivine, has the potential for superior energy output (>10.7 Wh in 18650 batteries), compared with commercial Li(Co,Ni)O 2 derivatives (up to 9.9 Wh). Speculative Co and Ni olivine cathode materials charged to above 4.5 V will require significant advances in electrolyte compositions and nanotechnology before commercialization. The major drivers toward 5 V battery chemistries are the inherent abuse tolerance of phosphates and the economic benefit of LiNiPO 4: it can produce 34% greater energy per dollar of cell material cost than LiAl 0.05Co 0.15Ni 0.8O 2, today's "standard" cathode intercalant in Li-ion batteries.

  12. New High Capacity Cathode Materials for Rechargeable Li-ion Batteries: Vanadate-Borate Glasses

    PubMed Central

    Afyon, Semih; Krumeich, Frank; Mensing, Christian; Borgschulte, Andreas; Nesper, Reinhard

    2014-01-01

    V2O5 based materials are attractive cathode alternatives due to the many oxidation state switches of vanadium bringing about a high theoretical specific capacity. However, significant capacity losses are eminent for crystalline V2O5 phases related to the irreversible phase transformations and/or vanadium dissolution starting from the first discharge cycle. These problems can be circumvented if amorphous or glassy vanadium oxide phases are employed. Here, we demonstrate vanadate-borate glasses as high capacity cathode materials for rechargeable Li-ion batteries for the first time. The composite electrodes of V2O5 – LiBO2 glass with reduced graphite oxide (RGO) deliver specific energies around 1000 Wh/kg and retain high specific capacities in the range of ~ 300 mAh/g for the first 100 cycles. V2O5 – LiBO2 glasses are considered as promising cathode materials for rechargeable Li-ion batteries fabricated through rather simple and cost-efficient methods. PMID:25408200

  13. Preparation and electrochemical performance of sulfur-alumina cathode material for lithium-sulfur batteries

    SciTech Connect

    Dong, Kang; Wang, Shengping; Zhang, Hanyu; Wu, Jinping

    2013-06-01

    Highlights: ► Micron-sized alumina was synthesized as adsorbent for lithium-sulfur batteries. ► Sulfur-alumina material was synthesized via crystallizing nucleation. ► The Al{sub 2}O{sub 3} can provide surface area for the deposition of Li{sub 2}S and Li{sub 2}S{sub 2}. ► The discharge capacity of the battery is improved during the first several cycles. - Abstract: Nano-sized sulfur particles exhibiting good adhesion with conducting acetylene black and alumina composite materials were synthesized by means of an evaporated solvent and a concentrated crystallization method for use as the cathodes of lithium-sulfur batteries. The composites were characterized and examined by X-ray diffraction, environmental scanning electron microscopy and electrochemical methods, such as cyclic voltammetry, electrical impedance spectroscopy and charge–discharge tests. Micron-sized flaky alumina was employed as an adsorbent for the cathode material. The initial discharge capacity of the cathode with the added alumina was 1171 mAh g{sup −1}, and the remaining capacity was 585 mAh g{sup −1} after 50 cycles at 0.25 mA cm{sup −2}. Compared with bare sulfur electrodes, the electrodes containing alumina showed an obviously superior cycle performance, confirming that alumina can contribute to reducing the dissolution of polysulfides into electrolytes during the sulfur charge–discharge process.

  14. Selective Recovery of Lithium from Cathode Materials of Spent Lithium Ion Battery

    NASA Astrophysics Data System (ADS)

    Higuchi, Akitoshi; Ankei, Naoki; Nishihama, Syouhei; Yoshizuka, Kazuharu

    2016-10-01

    Selective recovery of lithium from four kinds of cathode materials, manganese-type, cobalt-type, nickel-type, and ternary-type, of spent lithium ion battery was investigated. In all cathode materials, leaching of lithium was improved by adding sodium persulfate (Na2S2O8) as an oxidant in the leaching solution, while the leaching of other metal ions (manganese, cobalt, and nickel) was significantly suppressed. Optimum leaching conditions, such as pH, temperature, amount of Na2S2O8, and solid/liquid ratio, for the selective leaching of lithium were determined for all cathode materials. Recovery of lithium from the leachate as lithium carbonate (Li2CO3) was then successfully achieved by adding sodium carbonate (Na2CO3) to the leachate. Optimum recovery conditions, such as pH, temperature, and amount of Na2CO3, for the recovery of lithium as Li2CO3 were determined for all cases. Purification of Li2CO3 was achieved by lixiviation in all systems, with purities of the Li2CO3 higher than 99.4%, which is almost satisfactory for the battery-grade purity of lithium.

  15. Potassium nickel hexacyanoferrate as a high-voltage cathode material for nonaqueous magnesium-ion batteries

    NASA Astrophysics Data System (ADS)

    Chae, Munseok S.; Hyoung, Jooeun; Jang, Minchul; Lee, Hochun; Hong, Seung-Tae

    2017-09-01

    The magnesium insertion capability of Prussian blue (PB) analogue, potassium nickel hexacyanoferrate K0.86Ni[Fe(CN)6]0.954(H2O)0.766 (KNF-086), is demonstrated as a cathode material for rechargeable magnesium-ion batteries using a conventional organic electrolyte. K1.51Ni[Fe(CN)6]0.954(H2O)0.766 is synthesized first, and potassium ions are electrochemically extracted to prepare the KNF-086 cathode. The electrochemical test cell is composed of KNF-086 as the working electrode, an activated carbon as the counter and reference electrode, and 0.5 M Mg(ClO4)2 in acetonitrile as the electrolyte. The cell shows a reversible magnesium insertion/extraction reaction with a discharge capacity of 48.3 mAh g-1 at a 0.2 C rate, and an average discharge voltage at 2.99 V (vs. Mg/Mg2+) that is the highest among the cathode materials ever reported for magnesium-ion batteries. Elemental analysis and Fourier electron-density map analysis from powder X-ray diffraction data confirm that the magnesium-inserted phase is Mg0.27K0.86Ni[Fe(CN)6]0.954(H2O)0.766 (MKNF-086), and the magnesium ions in MKNF-086 are positioned at the center of the large interstitial cavities of cubic PB. Compared to KNF-086, MKNF-086 exhibits a decreased unit cell parameter (0.8%) and volume (2.4%). These results demonstrate that a PB analogue, potassium nickel hexacyanoferrate, could be utilized as a potential cathode material for conventional organic electrolyte-based magnesium-ion batteries.

  16. Ultrafast laser microstructuring of LiFePO4 cathode material

    NASA Astrophysics Data System (ADS)

    Mangang, M.; Pröll, J.; Tarde, C.; Seifert, H. J.; Pfleging, W.

    2014-03-01

    LiFePO4 is a very promising material to be used as positive electrode for future lithium-ion batteries. Nevertheless, a reduced rate capability at high discharging and charging currents is the main drawback. In this work, a 3D structure was made in LiFePO4 composite electrodes by applying ultrafast laser ablation. The change of the electrochemical properties in a lithium-ion half-cell due to laser structuring was studied in detail and will be discussed. The main challenging goal is to correlate cell properties such as capacity retention with laser parameters and laser generated microstructure. For microstructuring electrode materials an ultrafast as well as a ns fiber laser were used. The pulse duration was varied in the range from 350 fs to 200 ns. With ultrashort laser radiation, the ablation efficiency was increased. Electrochemical characterisations were performed. For this purpose, Swagelok® test cells with lithium metal as counter electrode were assembled. Main electrochemical parameters such as specific capacity and cycle stability were determined for the cells with structured and unstructured cathodes. It was shown that the rate capability for the cells with structured cathodes in comparison to cells with unstructured cathodes was significantly enhanced, especially for high charging and discharging rates.

  17. Electricity generation and bivalent copper reduction as a function of operation time and cathode electrode material in microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Wu, Dan; Huang, Liping; Quan, Xie; Li Puma, Gianluca

    2016-03-01

    The performance of carbon rod (CR), titanium sheet (TS), stainless steel woven mesh (SSM) and copper sheet (CS) cathode materials are investigated in microbial fuel cells (MFCs) for simultaneous electricity generation and Cu(II) reduction, in multiple batch cycle operations. After 12 cycles, the MFC with CR exhibits 55% reduction in the maximum power density and 76% increase in Cu(II) removal. In contrast, the TS and SSM cathodes at cycle 12 show maximum power densities of 1.7 (TS) and 3.4 (SSM) times, and Cu(II) removal of 1.2 (TS) and 1.3 (SSM) times higher than those observed during the first cycle. Diffusional resistance in the TS and SSM cathodes is found to appreciably decrease over time due to the copper deposition. In contrast to CR, TS and SSM, the cathode made with CS is heavily corroded in the first cycle, exhibiting significant reduction in both the maximum power density and Cu(II) removal at cycle 2, after which the performance stabilizes. These results demonstrate that the initial deposition of copper on the cathodes of MFCs is crucial for efficient and continuous Cu(II) reduction and electricity generation over prolonged time. This effect is closely associated with the nature of the cathode material. Among the materials examined, the SSM is the most effective and inexpensive cathode for practical use in MFCs.

  18. Triazine-based Polyelectrolyte as an Efficient Cathode Interfacial Material for Polymer Solar Cells.

    PubMed

    Chakravarthi, Nallan; Aryal, Um Kanta; Gunasekar, Kumarasamy; Park, Ho-Yeol; Gal, Yeong-Soon; Cho, Young-Rae; Yoo, Seong Il; Song, Myungkwan; Jin, Sung-Ho

    2017-07-26

    A novel polyelectrolyte containing triazine (TAZ) and benzodithiophene (BDT) scaffolds with polar phosphine oxide (P═O) and quaternary ammonium ions as pendant groups, respectively, in the polymer backbone (PBTAZPOBr) was synthesized to use it as a cathode interfacial layer (CIL) for polymer solar cell (PSC) application. Owing to the high electron affinity of the TAZ unit and P═O group, PBTAZPOBr could behave as an effective electron transport material. Due to the polar quaternary ammonium and P═O groups, the interfacial dipole moment created by PBTAZPOBr substantially reduced the work function of the metal cathode to afford better energy alignment in the device, thus enabling electron extraction and reducing recombination of excitons at the photoactive layer/cathode interface. Consequently, the PSC devices based on the poly[4,8-bis(2-ethylhexyloxyl)benzo[1,2-b:4,5-b']dithiophene-2,6-diyl-alt-ethylhexyl-3-fluorothithieno[3,4-b]thiophene-2-carboxylate-4,6-diyl]:[6,6]-phenyl-C71-butyric acid methyl ester (PTB7:PC71BM) system with PBTAZPOBr as CIL displayed simultaneously enhanced open-circuit voltage, short-circuit current density, and fill factor, whereas the power conversion efficiency increased from 5.42% to 8.04% compared to that of the pristine Al device. The outstanding performance of PBTAZPOBr is attributed not only to the polar pendant groups of BDT unit but also to the TAZ unit linked with the P═O group of PBTAZPOBr, demonstrating that functionalized TAZ building blocks are very promising cathode interfacial materials (CIMs). The design strategy proposed in this work will be helpful to develop more efficient CIMs for high performance PSCs in the future.

  19. High-Performance Polyoxometalate-Based Cathode Materials for Rechargeable Lithium-Ion Batteries.

    PubMed

    Chen, Jia-Jia; Symes, Mark D; Fan, Shao-Cong; Zheng, Ming-Sen; Miras, Haralampos N; Dong, Quan-Feng; Cronin, Leroy

    2015-08-19

    The polyoxovanadate cluster Li7[V15O36(CO3)] is shown to be an active cathode material in Li-ion batteries, delivering a capacity of 250 mA h g(-1) at 50 mA g(-1) and 140 mA h g(-1) at 10 A g(-1). Li-ion diffusion is rapid in this material and gives rise to an impressive maximum power density output of 25.7 kW kg(-1) (55 kW L(-1)). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Lattice-cell orientation disorder in complex spinel oxides

    DOE PAGES

    Chen, Yan; Cheng, Yongqiang; Li, Juchuan; ...

    2016-11-07

    Transition metal (TM) substitution has been widely applied to change complex oxides crystal structures to create high energy density electrodes materials in high performance rechargeable lithium-ion batteries. The complex local structure in the oxides imparted by the TM arrangement often impacts their electrochemical behaviors by influencing the diffusion and intercalation of lithium. Here, a major discrepancy is demonstrated between the global and local structures of the promising high energy density and high voltage LiNi0.5Mn1.5O4 spinel cathode material that contradicts the existing structural models. A new single-phase lattice-cell orientation disorder model is proposed as the mechanism for the local ordering thatmore » explains how the inhomogeneous local distortions and the coherent connection give rise to the global structure in the complex oxide. As a result, the single-phase model is consistent with the electrochemical behavior observation of the materials.« less

  1. Lattice-cell orientation disorder in complex spinel oxides

    SciTech Connect

    Chen, Yan; Cheng, Yongqiang; Li, Juchuan; Feygenson, Mikhail; Heller, William T.; Liang, Chengdu; An, Ke

    2016-11-07

    Transition metal (TM) substitution has been widely applied to change complex oxides crystal structures to create high energy density electrodes materials in high performance rechargeable lithium-ion batteries. The complex local structure in the oxides imparted by the TM arrangement often impacts their electrochemical behaviors by influencing the diffusion and intercalation of lithium. Here, a major discrepancy is demonstrated between the global and local structures of the promising high energy density and high voltage LiNi0.5Mn1.5O4 spinel cathode material that contradicts the existing structural models. A new single-phase lattice-cell orientation disorder model is proposed as the mechanism for the local ordering that explains how the inhomogeneous local distortions and the coherent connection give rise to the global structure in the complex oxide. As a result, the single-phase model is consistent with the electrochemical behavior observation of the materials.

  2. Load displacement and high speed nanoindentation data set at different state of charge (SoC) for spinel Li x Mn2O4 cathodes.

    PubMed

    Mughal, Muhammad Zeeshan; Moscatelli, Riccardo; Sebastiani, Marco

    2016-09-01

    Novel high speed nanoindentation data is reported for 0% and 100% state of charge (SoC) for the spinal Li x Mn2O4 material. The article also includes the load/displacement data for different SoC highlighting the displacement bursts corresponding to the pillar splitting for fracture toughness evaluation. For more details, please see the article; Mughal et al. (2016) [1].

  3. Synthesis and Electrochemical Properties of LiNi0.5Mn1.5O4 Cathode Materials with Cr3+ and F- Composite Doping for Lithium-Ion Batteries

    NASA Astrophysics Data System (ADS)

    Li, Jun; Li, Shaofang; Xu, Shuaijun; Huang, Si; Zhu, Jianxin

    2017-06-01

    A Cr3+ and F- composite-doped LiNi0.5Mn1.5O4 cathode material was synthesized by the solid-state method, and the influence of the doping amount on the material's physical and electrochemical properties was investigated. The structure and morphology of the cathode material were characterized by XRD, SEM, TEM, and HRTEM, and the results revealed that the sample exhibited clear spinel features. No Cr3+ and F- impurity phases were found, and the spinel structure became more stable. The results of the charge/discharge tests, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) test results suggested that LiCr0.05Ni0.475Mn1.475O3.95F0.05 in which the Cr3+ and F- doping amounts were both 0.05, had the optimal electrochemical properties, with discharge rates of 0.1, 0.5, 2, 5, and 10 C and specific capacities of 134.18, 128.70, 123.62, 119.63, and 97.68 mAh g-1 , respectively. After 50 cycles at a rate of 2 C, LiCr0.05Ni0.475Mn1.475O3.95F0.05 showed extremely good cycling performance, with a discharge specific capacity of 121.02 mAh g-1 and a capacity retention rate of 97.9%. EIS test revealed that the doping clearly decreased the charge-transfer resistance.

  4. Synthesis and Electrochemical Properties of LiNi0.5Mn1.5O4 Cathode Materials with Cr(3+) and F(-) Composite Doping for Lithium-Ion Batteries.

    PubMed

    Li, Jun; Li, Shaofang; Xu, Shuaijun; Huang, Si; Zhu, Jianxin

    2017-12-01

    A Cr(3+) and F(-) composite-doped LiNi0.5Mn1.5O4 cathode material was synthesized by the solid-state method, and the influence of the doping amount on the material's physical and electrochemical properties was investigated. The structure and morphology of the cathode material were characterized by XRD, SEM, TEM, and HRTEM, and the results revealed that the sample exhibited clear spinel features. No Cr(3+) and F(-) impurity phases were found, and the spinel structure became more stable. The results of the charge/discharge tests, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) test results suggested that LiCr0.05Ni0.475Mn1.475O3.95F0.05 in which the Cr(3+) and F(-) doping amounts were both 0.05, had the optimal electrochemical properties, with discharge rates of 0.1, 0.5, 2, 5, and 10 C and specific capacities of 134.18, 128.70, 123.62, 119.63, and 97.68 mAh g(-1) , respectively. After 50 cycles at a rate of 2 C, LiCr0.05Ni0.475Mn1.475O3.95F0.05 showed extremely good cycling performance, with a discharge specific capacity of 121.02 mAh g(-1) and a capacity retention rate of 97.9%. EIS test revealed that the doping clearly decreased the charge-transfer resistance.

  5. Improving the rate capability of high voltage lithium-ion battery cathode material LiNi0.5Mn1.5O4 by ruthenium doping

    NASA Astrophysics Data System (ADS)

    Kiziltas-Yavuz, Nilüfer; Bhaskar, Aiswarya; Dixon, Ditty; Yavuz, Murat; Nikolowski, Kristian; Lu, Li; Eichel, Rüdiger-A.; Ehrenberg, Helmut

    2014-12-01

    The citric acid-assisted sol-gel method was used to produce the high-voltage cathodes LiNi0.5Mn1.5O4 and LiNi0.4Ru0.05Mn1.5O4 at 800 °C and 1000 °C final calcination temperatures. High resolution powder diffraction using synchrotron radiation, inductively coupled plasma - optical emission spectroscopy and scanning electron microscopy analyses were carried out to characterize the structure, chemical composition and morphology. X-ray absorption spectroscopy studies were conducted to confirm Ru doping inside the spinel as well as to compare the oxidation states of transition metals. The formation of an impurity LixNi1-xO in LiNi0.5Mn1.5O4 powders annealed at high temperatures (T ≥ 800 °C) can be suppressed by partial substitution of Ni2+ by Ru4+ ion. The LiNi0.4Ru0.05Mn1.5O4 powder synthesized at 1000 °C shows the highest performance regarding the rate capability and cycling stability. It has an initial capacity of ∼139 mAh g-1 and capacity retention of 84% after 300 cycles at C/2 charging-discharging rate between 3.5 and 5.0 V. The achievable discharge capacity at 20 C for a charging rate of C/2 is ∼136 mAh g-1 (∼98% of the capacity delivered at C/2). Since the electrode preparation plays a crucial role on parameters like the rate capability, the influence of the mass loading of active materials in the cathode mixture is discussed.

  6. Synthesis, strctural and electrochemical characterizations of lithium- manganese- rich composite cathode materials for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Wang, Dapeng

    The electrification trend for transportation systems requires alternative cathode materials to LiCoO2 with improved safety, lowered cost and extended cycle life. Lithium- manganese- rich composite cathode materials, which can be presented in a two component notation as xLi2MnO3·(1-x)LiMO 2, (M= Ni, Co or Mn) have superior cost and energy density advantages. These cathode materials have shown success in laboratory scale experiments, but are still facing challenges such as voltage fade, moderate rate capacity and tap density for commercialization. The synthesis of precursors with high packing density and suitable physical properties is critical to achieve high energy density as well as the other acceptable electrochemical performance for the next generation lithium ion batteries. The aim of this study is to correlate the electrochemical properties of materials to their structural, morphological, and physical properties by coordinating the science of synthesis with the science of function, in order to enable the use of these compounds in vehicle technologies. Three different precursors including carbonate, hydroxide and oxalate were synthesized by co-precipitation reactions using continuous stirred tank reactor (CSTR) under various conditions. Research focused on areas such as nucleation and growth mechanisms, synthesis optimizations, and intrinsic limitations of each co-precipitation method. A combination of techniques such as PSA, BET, SEM, EDX FIB, TEM, Raman, FTIR, TGA-DSC, XRD, and ICP-MS, as well as electrochemical test methods such as cycling, CV, EIS and HPPC tests were used in correlation with each other in order to deepen our understanding to these materials. Related topics such as the composite structure formation process during the solid state reaction, lithium and nickel content effects on the cathode properties were also discussed. Additionally, the side reactions between the active materials and electrolyte as a result of the high charge potential were

  7. Optimization of the cathode material for nitrate removal by a paired electrolysis process.

    PubMed

    Reyter, David; Bélanger, Daniel; Roué, Lionel

    2011-08-30

    Ni, Cu, Cu(90)Ni(10) and Cu(70)Ni(30) were evaluated as cathode materials for the conversion of nitrate to nitrogen by a paired electrolysis process using an undivided flow-through electrolyzer. Firstly, corrosion measurements revealed that Ni and Cu(70)Ni(30) electrodes have a much better corrosion resistance than Cu and Cu(90)Ni(10) in the presence of chloride, nitrate and ammonia. Secondly, nitrate electroreduction experiments showed that the cupro-nickel electrodes are the most efficient for reducing nitrate to ammonia with a selectivity of 100%. Finally, paired electrolysis experiments confirmed the efficiency of Cu(70)Ni(30) and Cu(90)Ni(10) cathodes for the conversion of nitrate to nitrogen. During a typical electrolysis, the concentration of nitrate varied from 620ppm to less than 50ppm NO(3)(-) with an N(2) selectivity of 100% and a mean energy consumption of 20kWh/kg NO(3)(-) (compared to ∼35 and ∼220kWh/kg NO(3)(-) with Cu and Ni cathodes, respectively).

  8. Optimization of electron transport and cathode materials for efficient organic solar cells

    NASA Astrophysics Data System (ADS)

    Colsmann, Alexander; Junge, Johannes; Wellinger, Thomas; Kayser, Christian; Lemmer, Uli

    2006-04-01

    In this work we discuss improvements of organic solar cells based on poly(3-hexylthiophene-2,5-diyl) : C 61-butyric acid methyl ester (P3HT:PCBM) blends. The polymer layer is combined with various electron transport materials and different cathodes. We were able to utilize the good charge carrier separation and transport properties of the P3HT:PCBM blend together with the flexibility of evaporated heterostructures. The systematic use of different cathodes such as calcium, aluminium/lithiumfluoride and organic intermediate layers resulted in higher fill factors and open circuit voltages compared to simple aluminium cathodes. In particular we studied the influence of additional layers of electron transport layer consisting of C 60, lithium doped bathophenanthroline (BPhen:Li) 2-(4-tert-butylphenyl)-5-(4-biphenylyl)-1,3,4-oxadiazole (PBD) and 2,9- dimethyl-4,7-diphenyl-1,10-phenantrolene (BCP) on the cell properties. Solar cells with power conversion efficiencies well above 3% have been fabricated.

  9. Dynamic behaviour of interphases and its implication on high-energy-density cathode materials in lithium-ion batteries

    PubMed Central

    Li, Wangda; Dolocan, Andrei; Oh, Pilgun; Celio, Hugo; Park, Suhyeon; Cho, Jaephil; Manthiram, Arumugam

    2017-01-01

    Undesired electrode–electrolyte interactions prevent the use of many high-energy-density cathode materials in practical lithium-ion batteries. Efforts to address their limited service life have predominantly focused on the active electrode materials and electrolytes. Here an advanced three-dimensional chemical and imaging analysis on a model material, the nickel-rich layered lithium transition-metal oxide, reveals the dynamic behaviour of cathode interphases driven by conductive carbon additives (carbon black) in a common nonaqueous electrolyte. Region-of-interest sensitive secondary-ion mass spectrometry shows that a cathode-electrolyte interphase, initially formed on carbon black with no electrochemical bias applied, readily passivates the cathode particles through mutual exchange of surface species. By tuning the interphase thickness, we demonstrate its robustness in suppressing the deterioration of the electrode/electrolyte interface during high-voltage cell operation. Our results provide insights on the formation and evolution of cathode interphases, facilitating development of in situ surface protection on high-energy-density cathode materials in lithium-based batteries. PMID:28443608

  10. Highly stable TiO2 coated Li2MnO3 cathode materials for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Kim, Si-Jin; Kim, Min-Cheol; Kwak, Da-Hee; Kim, Da-Mi; Lee, Gyu-Ho; Choe, Hui-Seon; Park, Kyung-Won

    2016-02-01

    Many efforts have been made to improve the electrochemical performance of Li-rich cathode materials such as metal ion doping, surface modification, and fabricating nanostructured materials. Here, we demonstrate Li2MnO3 (denoted as OLO) cathode materials coated with TiO2 (OLO@ TiO2) for high-performance LIBs. The ratio of layered Li2MnO3 to anatase TiO2 as well as the shell thickness in the OLO@TiO2 cathodes were controlled by increasing the addition of titanium butoxide. The structure and chemical states for TiO2 coated OLO electrodes were confirmed using field-emission scanning electron microscopy, field-emission transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. To evaluate the performance of the electrodes for LIBs, charge/discharge curves, cycling performance, cyclic voltammograms, and Nyquist plots of the as-prepare cathode materials were obtained using lithium coin cells. In particular, since the TiO2 coating layer in OLO@TiO2 could stabilize the interface between the cathode and electrolyte, OLO@TiO2 exhibited high specific capacity, improved high rate cycling performance, and excellent cycle life due to the low interface resistance and high diffusion coefficient of lithium ion, compared with the uncoated OLO cathode.

  11. Dynamic behaviour of interphases and its implication on high-energy-density cathode materials in lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Li, Wangda; Dolocan, Andrei; Oh, Pilgun; Celio, Hugo; Park, Suhyeon; Cho, Jaephil; Manthiram, Arumugam

    2017-04-01

    Undesired electrode-electrolyte interactions prevent the use of many high-energy-density cathode materials in practical lithium-ion batteries. Efforts to address their limited service life have predominantly focused on the active electrode materials and electrolytes. Here an advanced three-dimensional chemical and imaging analysis on a model material, the nickel-rich layered lithium transition-metal oxide, reveals the dynamic behaviour of cathode interphases driven by conductive carbon additives (carbon black) in a common nonaqueous electrolyte. Region-of-interest sensitive secondary-ion mass spectrometry shows that a cathode-electrolyte interphase, initially formed on carbon black with no electrochemical bias applied, readily passivates the cathode particles through mutual exchange of surface species. By tuning the interphase thickness, we demonstrate its robustness in suppressing the deterioration of the electrode/electrolyte interface during high-voltage cell operation. Our results provide insights on the formation and evolution of cathode interphases, facilitating development of in situ surface protection on high-energy-density cathode materials in lithium-based batteries.

  12. Dynamic behaviour of interphases and its implication on high-energy-density cathode materials in lithium-ion batteries

    DOE PAGES

    Li, Wangda; Dolocan, Andrei; Oh, Pilgun; ...

    2017-04-26

    Undesired electrode–electrolyte interactions prevent the use of many high-energy-density cathode materials in practical lithium-ion batteries. Efforts to address their limited service life have predominantly focused on the active electrode materials and electrolytes. Here an advanced three-dimensional chemical and imaging analysis on a model material, the nickel-rich layered lithium transition-metal oxide, reveals the dynamic behaviour of cathode interphases driven by conductive carbon additives (carbon black) in a common nonaqueous electrolyte. Region-of-interest sensitive secondary-ion mass spectrometry shows that a cathode-electrolyte interphase, initially formed on carbon black with no electrochemical bias applied, readily passivates the cathode particles through mutual exchange of surface species.more » By tuning the interphase thickness, we demonstrate its robustness in suppressing the deterioration of the electrode/electrolyte interface during high-voltage cell operation. Finally, our results provide insights on the formation and evolution of cathode interphases, facilitating development of in situ surface protection on high-energy-density cathode materials in lithium-based batteries.« less

  13. Dynamic behaviour of interphases and its implication on high-energy-density cathode materials in lithium-ion batteries.

    PubMed

    Li, Wangda; Dolocan, Andrei; Oh, Pilgun; Celio, Hugo; Park, Suhyeon; Cho, Jaephil; Manthiram, Arumugam

    2017-04-26

    Undesired electrode-electrolyte interactions prevent the use of many high-energy-density cathode materials in practical lithium-ion batteries. Efforts to address their limited service life have predominantly focused on the active electrode materials and electrolytes. Here an advanced three-dimensional chemical and imaging analysis on a model material, the nickel-rich layered lithium transition-metal oxide, reveals the dynamic behaviour of cathode interphases driven by conductive carbon additives (carbon black) in a common nonaqueous electrolyte. Region-of-interest sensitive secondary-ion mass spectrometry shows that a cathode-electrolyte interphase, initially formed on carbon black with no electrochemical bias applied, readily passivates the cathode particles through mutual exchange of surface species. By tuning the interphase thickness, we demonstrate its robustness in suppressing the deterioration of the electrode/electrolyte interface during high-voltage cell operation. Our results provide insights on the formation and evolution of cathode interphases, facilitating development of in situ surface protection on high-energy-density cathode materials in lithium-based batteries.

  14. Elastomeric Cathode Binder

    NASA Technical Reports Server (NTRS)

    Yen, S. P. S.; Shen, D. S.; Somoano, R. B.

    1985-01-01

    Soluble copolymer binder mixed with cathode material and solvent forms flexible porous cathode used in lithium and Ni/Cd batteries. Cathodes prepared by this process have lower density due to expanding rubbery binder and greater flexibility than conventional cathodes. Fabrication procedure readily adaptable to scaled-up processes.

  15. Crystal Chemistry and Electrochemistry of LixMn1.5Ni0.5O4 Solid Solution Cathode Materials

    DOE PAGES

    Kan, Wang Hay; Kuppan, Saravanan; Cheng, Lei; ...

    2017-07-19

    For ordered high-voltage spinel LiMn1.5Ni0.5O4 (LMNO) with the P4321 symmetry, the two consecutive two-phase transformations at ~4.7 V (vs Li+/Li), involving three cubic phases of LMNO, Li0.5Mn1.5Ni0.5O4 (L0.5MNO), and Mn1.5Ni0.5O4 (MNO), have been well-established. Such a mechanism is traditionally associated with poor kinetics due to the slow movement of the phase boundaries and the large mechanical strain resulting from the volume changes among the phases, yet ordered LMNO has been shown to have excellent rate capability. In this paper, we show the ability of the phases to dissolve into each other and determine their solubility limit. We characterized the propertiesmore » of the formed solid solutions and investigated the role of non-equilibrium single-phase redox processes during the charge and discharge of LMNO. Finally, by using an array of advanced analytical techniques, such as soft and hard X-ray spectroscopy, transmission X-ray microscopy, and neutron/X-ray diffraction, as well as bond valence sum analysis, the present study examines the metastable nature of solid-solution phases and provides new insights in enabling cathode materials that are thermodynamically unstable.« less

  16. Crystal Chemistry and Electrochemistry of LixMn1.5Ni0.5O4 Solid Solution Cathode Materials

    DOE PAGES

    Kan, Wang Hay; Kuppan, Saravanan; Cheng, Lei; ...

    2017-07-19

    For ordered high-voltage spinel LiMn1.5Ni0.5O4 (LMNO) with the P4321 symmetry, the two consecutive two-phase transformations at ~4.7 V (vs Li+/Li), involving three cubic phases of LMNO, Li0.5Mn1.5Ni0.5O4 (L0.5MNO), and Mn1.5Ni0.5O4 (MNO), have been well-established. Such a mechanism is traditionally associated with poor kinetics due to the slow movement of the phase boundaries and the large mechanical strain resulting from the volume changes among the phases, yet ordered LMNO has been shown to have excellent rate capability. In this study, we show the ability of the phases to dissolve into each other and determine their solubility limit. We characterized the propertiesmore » of the formed solid solutions and investigated the role of non-equilibrium single-phase redox processes during the charge and discharge of LMNO. Here by using an array of advanced analytical techniques, such as soft and hard X-ray spectroscopy, transmission X-ray microscopy, and neutron/X-ray diffraction, as well as bond valence sum analysis, the present study examines the metastable nature of solid-solution phases and provides new insights in enabling cathode materials that are thermodynamically unstable.« less

  17. Rational design of novel cathode materials in solid oxide fuel cells using first-principles simulations

    NASA Astrophysics Data System (ADS)

    Choi, YongMan; Lin, M. C.; Liu, Meilin

    The search for clean and renewable sources of energy represents one of the most vital challenges facing us today. Solid oxide fuel cells (SOFCs) are among the most promising technologies for a clean and secure energy future due to their high energy efficiency and excellent fuel flexibility (e.g., direct utilization of hydrocarbons or renewable fuels). To make SOFCs economically competitive, however, development of new materials for low-temperature operation is essential. Here we report our results on a computational study to achieve rational design of SOFC cathodes with fast oxygen reduction kinetics and rapid ionic transport. Results suggest that surface catalytic properties are strongly correlated with the bulk transport properties in several material systems with the formula of La 0.5Sr 0.5BO 2.75 (where B = Cr, Mn, Fe, or Co). The predictions seem to agree qualitatively with available experimental results on these materials. This computational screening technique may guide us to search for high-efficiency cathode materials for a new generation of SOFCs.

  18. Metal segregation in hierarchically structured cathode materials for high-energy lithium batteries

    SciTech Connect

    Lin, Feng; Xin, Huolin L.; Nordlund, Dennis; Li, Yuyi; Quan, Matthew K.; Cheng, Lei; Weng, Tsu -Chien; Liu, Yijin; Doeff, Marca M.

    2016-01-11

    Controlling surface and interfacial properties of battery materials is key to improving performance in rechargeable Li-ion devices. Surface reconstruction from a layered to a rock salt structure in metal oxide cathode materials is commonly observed and results in poor high-voltage cycling performance, impeding attempts to improve energy density. Hierarchically structured LiNi0.4Mn0.4Co0.2O2 (NMC-442) spherical powders, made by spray pyrolysis, exhibit local elemental distribution gradients that deviate from the global NMC-442 composition; specifically, they are Ni-rich and Mn-poor at particle surfaces. These materials demonstrate improved Coulombic efficiencies, discharge capacities, and high-voltage capacity retention in lithium half-cell configurations. The subject powders show superior resistance against surface reconstruction due to the tailored surface chemistry, compared to conventional NMC-442 materials. This paves the way towards the development of a new generation of robust and stable high-energy NMC cathodes for Li-ion batteries.

  19. Metal segregation in hierarchically structured cathode materials for high-energy lithium batteries

    DOE PAGES

    Lin, Feng; Xin, Huolin L.; Nordlund, Dennis; ...

    2016-01-11

    Controlling surface and interfacial properties of battery materials is key to improving performance in rechargeable Li-ion devices. Surface reconstruction from a layered to a rock salt structure in metal oxide cathode materials is commonly observed and results in poor high-voltage cycling performance, impeding attempts to improve energy density. Hierarchically structured LiNi0.4Mn0.4Co0.2O2 (NMC-442) spherical powders, made by spray pyrolysis, exhibit local elemental distribution gradients that deviate from the global NMC-442 composition; specifically, they are Ni-rich and Mn-poor at particle surfaces. These materials demonstrate improved Coulombic efficiencies, discharge capacities, and high-voltage capacity retention in lithium half-cell configurations. The subject powders show superiormore » resistance against surface reconstruction due to the tailored surface chemistry, compared to conventional NMC-442 materials. This paves the way towards the development of a new generation of robust and stable high-energy NMC cathodes for Li-ion batteries.« less

  20. Polyimide encapsulated lithium-rich cathode material for high voltage lithium-ion battery.

    PubMed

    Zhang, Jie; Lu, Qingwen; Fang, Jianhua; Wang, Jiulin; Yang, Jun; NuLi, Yanna

    2014-10-22

    Lithium-rich materials represented by xLi2MnO3·(1 - x)LiMO2 (M = Mn, Co, Ni) are attractive cathode materials for lithium-ion battery due to their high specific energy and low cost. However, some drawbacks of these materials such as poor cycle and rate capability remain to be addressed before applications. In this study, a thin polyimide (PI) layer is coated on the surface of Li1.2Ni0.13Mn0.54Co0.13O2 (LNMCO) by a polyamic acid (PAA) precursor with subsequently thermal imidization process. X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HR-TEM) results confirm the successful formation of a PI layer (∼3 nm) on the surface of LNMCO without destruction of its main structure. X-ray photoelectron spectroscopy (XPS) spectra show a slight shift of the Mn valence state from Mn(IV) to Mn(III) in the PI-LNMCO treated at 450 °C, elucidating that charge transfer takes place between the PI layer and LNMCO surface. Electrochemical performances of LNMCO including cyclic stability and rate capability are evidently improved by coating a PI nanolayer, which effectively separates the cathode material from the electrolyte and stabilizes their interface at high voltage.

  1. Mesoscale Evaluation of Titanium Silicide Monolayer as a Cathode Host Material in Lithium-Sulfur Batteries

    NASA Astrophysics Data System (ADS)

    Liu, Zhixiao; Balbuena, Perla B.; Mukherjee, Partha P.

    2017-06-01

    Two-dimensional materials are competitive candidates as cathode materials in lithium-sulfur batteries for immobilizing soluble polysulfides and mitigating the shuttle effect. In this study, a mesoscale modeling approach, which combines first-principles simulation and kinetic Monte Carlo simulation, is employed to evaluate titanium silicide (Ti2Si and TiSi2) monolayers as potential host materials in lithium-sulfur batteries. It is found that the Ti2Si monolayer has much stronger affinities to Li2S x (x = 1, 2, 4) molecules than does the TiSi2 monolayer. Also, Ti2Si can facilitate the dissociation of long-chain Li2S4 to LiS2. On the other hand, TiSi2 can only provide a weak chemical interaction for trapping soluble Li2S4. Therefore, the Ti2Si monolayer can be considered to be the next-generation cathode material for lithium-sulfur batteries. Nevertheless, the strong interaction between Ti2Si and Li2S also causes fast surface passivation. How to control the Li2S precipitation on Ti2Si should be answered by future studies.

  2. Mesoscale Evaluation of Titanium Silicide Monolayer as a Cathode Host Material in Lithium-Sulfur Batteries

    NASA Astrophysics Data System (ADS)

    Liu, Zhixiao; Balbuena, Perla B.; Mukherjee, Partha P.

    2017-09-01

    Two-dimensional materials are competitive candidates as cathode materials in lithium-sulfur batteries for immobilizing soluble polysulfides and mitigating the shuttle effect. In this study, a mesoscale modeling approach, which combines first-principles simulation and kinetic Monte Carlo simulation, is employed to evaluate titanium silicide (Ti2Si and TiSi2) monolayers as potential host materials in lithium-sulfur batteries. It is found that the Ti2Si monolayer has much stronger affinities to Li2S x ( x = 1, 2, 4) molecules than does the TiSi2 monolayer. Also, Ti2Si can facilitate the dissociation of long-chain Li2S4 to LiS2. On the other hand, TiSi2 can only provide a weak chemical interaction for trapping soluble Li2S4. Therefore, the Ti2Si monolayer can be considered to be the next-generation cathode material for lithium-sulfur batteries. Nevertheless, the strong interaction between Ti2Si and Li2S also causes fast surface passivation. How to control the Li2S precipitation on Ti2Si should be answered by future studies.

  3. Performance study of commercial LiCoO 2 and spinel-based Li-ion cells

    NASA Astrophysics Data System (ADS)

    Ramadass, P.; Haran, Bala; White, Ralph; Popov, Branko N.

    The performance of Cell-Batt ® Li-ion cells and Sony 18650 cells using non-stoichiometric spinel and LiCoO 2, respectively, as positive electrode material has been studied under several modes of charging. During cycling, the cells were opened at intermittent cycles and extensive material and electrochemical characterization was done on the active material at both electrodes. Capacity fade of spinel-based Li-ion cells was attributed to structural degradation at the cathode and loss of active material at both electrodes due to electrolyte oxidation. For the Sony cells both primary (Li +) and secondary active material (LiCoO 2)/C) are lost during cycling.

  4. New insights into low temperature properties of Li-rich layered cathode materials

    NASA Astrophysics Data System (ADS)

    Liu, Guobiao; Li, Shaomin; Mei, Jun; Liu, Li-Min; Cui, Yanhua; Liu, Hao

    2017-06-01

    Since Li-ion batteries made of Li-rich layered materials might work at extreme environments, understanding the low temperature properties of Li-rich layered materials is of great importance. In this article, the low temperature properties and corresponding mechanism of Li-rich layered materials with a great amount of activated Li2MnO3 are unraveled through a comparison of the low temperature characteristics of Li-rich layered materials with a small amount of activated Li2MnO3 versus the former. Our findings indicate that in the electrode with a large amount of activated Li2MnO3, the sluggish kinetics of the electrode reaction at low temperatures suppresses greatly the Mn4+/Mn3+ reduction reaction, leading to much smaller initial discharge capacity and much better cyclic performance compared with situations at room temperature. Moreover, the increasingly suppressed Mn4+/Mn3+ reduction reaction stop the discharge voltage fading, which might mitigate the layered-to-spinel phase transformation.

  5. Grain boundary driven capacity fade/hysteresis abated in composite cathode material for lithium-ion batteries/pouch cell

    NASA Astrophysics Data System (ADS)

    Manikandan, P.; Periasamy, P.; Jagannathan, R.

    2014-10-01

    The composite cathode material LiNi1/3Mn1/3Co1/3O2:LiNi0.5Mn0.5O2 (wt. % 75:25) comprising the blend of well characterized LiNi1/3Mn1/3Co1/3O2 and LiNi0.5Mn0.5O2 materials has been synthesized through a facile thermolysis employing mixed hydroxy-carbonate precursor. This composite cathode material yielded impressive charge-discharge profile with a capacity of 213/194 mAh g-1 at 0.1 C and amazing coulombic efficiency of 99.4% at 50th cycle. Notwithstanding impressive initial charge-discharge capacity of the individual LNMC phase 224/187 mAh g-1 attributed to sharp edges of the cathode particles showed large irreversible capacity-hysteresis. Near absence of irreversible capacity observed upon discharging the composite cathode material can be attributed to milled/smoothened cathode particles of the composite cathode material offering little scope for energy loss in contrast to sharp edge-grain boundary induced irreversibility-hysteresis seen in the individual phases (LiNi1/3Mn1/3Co1/3O2 and LiNi0.5Mn0.5O2). The application scope of the high performance composite cathode material has been widened in conjunction with graphitic alloy anode (G0.65Ni0.05Ti0.15Sn0.15) material as demonstrated with the fabrication of W-weaving style design of Li-ion pouch cell (∼500 mAh) at moderate loads 0.12 Wh, 1.1 Wh.

  6. Thermodynamic stability of perovskite and lanthanum nickelate-type cathode materials for solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Cetin, Deniz

    The need for cleaner and more efficient alternative energy sources is becoming urgent as concerns mount about climate change wrought by greenhouse gas emissions. Solid oxide fuel cells (SOFCs) are one of the most efficient options if the goal is to reduce emissions while still operating on fossil energy resources. One of the foremost problems in SOFCs that causes efficiency loss is the polarization resistance associated with the oxygen reduction reaction(ORR) at the cathodes. Hence, improving the cathode design will greatly enhance the overall performance of SOFCs. Lanthanum nickelate, La2NiO4+delta (LNO), is a mixed ionic and electronic conductor that has competitive surface oxygen exchange and transport properties and excellent electrical conductivity compared to perovskite-type oxides. This makes it an excellent candidate for solid oxide fuel cell (SOFC) applications. It has been previously shown that composites of LNO with Sm0.2Ce0.8O2-delta (SDC20) as cathode materials lead to higher performance than standalone LNO. However, in contact with lanthanide-doped ceria, LNO decomposes resulting in free NiO and ceria with higher lanthanide dopant concentration. In this study, the aforementioned instability of LNO has been addressed by compositional tailoring of LNO: lanthanide doped ceria (LnxCe 1-xO2,LnDC)composite. By increasing the lanthanide dopant concentration in the ceria phase close to its solubility limit, the LNO phase has been stabilized in the LNO:LnDC composites. Electrical conductivity of the composites as a function of LNO volume fraction and temperature has been measured, and analyzed using a resistive network model which allows the identification of a percolation threshold for the LNO phase. The thermomechanical compatibility of these composites has been investigated with SOFC systems through measurement of the coefficients of thermal expansion. LNO:LDC40 composites containing LNO lower than 50 vol%and higher than 40 vol% were identified as being

  7. Lithium iron phosphates as cathode materials in lithium ion batteries for electric vehicles

    NASA Astrophysics Data System (ADS)

    Wang, Gaojun; Chen, Linfeng; Mathur, Gyanesh N.; Varadan, Vijay K.

    2012-04-01

    Olivine-structured lithium iron phosphates are promising cathode materials in the development of high power lithium ion batteries for electric vehicles. However, the low electronic conductivity and ionic conductivity of lithium iron phosphates hinder their commercialization pace. This work aims to verify the approaches for improving the electrochemical properties of lithium iron phosphates. In this work, sol-gel method was used to synthesize carbon coated lithium iron phosphates and nickel doped lithium iron phosphates, and their particle sizes were controlled in the nanometer to sub-micrometer range. The crystalline structures of the synthesized lithium iron phosphates were characterized by X-ray diffraction, and their morphologies were analyzed by scanning electron microscopy. To study their electrochemical properties, prototype lithium ion batteries were assembled with the synthesized lithium iron phosphates as cathode active materials, and with lithium metal discs as the anodes, and the discharge / charge properties and cycling behaviors of the prototype batteries were tested at different rates. The synthesized lithium iron phosphate materials exhibited high capacity and high cycling stability. It was confirmed that particle size reduction, carbon coating and metal doping are three effective approaches for increasing the conductivity of lithium iron phosphates, and thus improving their electrochemical properties. Experimental results show that by combing the three approaches for improving the electrochemical properties, lithium iron phosphate composites with characteristics favorable for their applications in lithium ion batteries for electric vehicles can be developed, including high specific capacity, high rate capacity, flat discharge voltage plateau and high retention ratio.

  8. Li2C2, a High-Capacity Cathode Material for Lithium Ion Batteries.

    PubMed

    Tian, Na; Gao, Yurui; Li, Yurong; Wang, Zhaoxiang; Song, Xiaoyan; Chen, Liquan

    2016-01-11

    As a typical alkaline earth metal carbide, lithium carbide (Li2C2) has the highest theoretical specific capacity (1400 mA h g(-1)) among all the reported lithium-containing cathode materials for lithium ion batteries. Herein, the feasibility of using Li2C2 as a cathode material was studied. The results show that at least half of the lithium can be extracted from Li2C2 and the reversible specific capacity reaches 700 mA h g(-1). The C≡C bond tends to rotate to form C4 (C≡C⋅⋅⋅C≡C) chains during lithium extraction, as indicated with the first-principles molecular dynamics (FPMD) simulation. The low electronic and ionic conductivity are believed to be responsible for the potential gap between charge and discharge, as is supported with density functional theory (DFT) calculations and Arrhenius fitting results. These findings illustrate the feasibility to use the alkali and alkaline earth metal carbides as high-capacity electrode materials for secondary batteries. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Microwave-assisted synthesis of high-voltage nanostructured LiMn1.5Ni0.5O4 spinel: tuning the Mn3+ content and electrochemical performance.

    PubMed

    Jafta, Charl J; Mathe, Mkhulu K; Manyala, Ncholu; Roos, Wiets D; Ozoemena, Kenneth I

    2013-08-14

    The LiMn1.5Ni0.5O4 spinel is an important lithium ion battery cathode material that has continued to receive major research attention because of its high operating voltage (∼4.8 V). This study interrogates the impact of microwave irradiation on the Mn(3+) concentration and electrochemistry of the LiMn1.5Ni0.5O4 spinel. It is shown that microwave is capable of tuning the Mn(3+) content of the spinel for enhanced electrochemical performance (high capacity, high capacity retention, excellent rate capability, and fast Li(+) insertion/extraction kinetics). This finding promises to revolutionize the application of microwave irradiation for improved performance of the LiMn1.5Ni0.5O4 spinel, especially in high rate applications.

  10. Self-organization of amine-based cathode interfacial materials in inverted polymer solar cells.

    PubMed

    Ma, Di; Lv, Menglan; Lei, Ming; Zhu, Jin; Wang, Haiqiao; Chen, Xiwen

    2014-02-25

    We present a strategy to fabricate polymer solar cells in inverted geometry by self-organization of alcohol soluble cathode interfacial materials in donor-acceptor bulk heterojunction blends. An amine-based fullerene [6,6]-phenyl-C61-butyric acid 2-((2-(dimethylamino)-ethyl)(methyl)amino)ethyl ester (PCBDAN) is used as an additive in poly(3-hexylthiophene) (P3HT) and 6,6-phenyl C61-butyric acid methyl ester (PCBM) blend to give a power conversion efficiency of 3.7% based on devices ITO/P3HT:PCBM:PCBDAN/MoO3/Ag where the ITO alone is used as the cathode. A vertical phase separation in favor of the inverted device architecture is formed: PCBDAN is rich on buried ITO surface reducing its work function, while P3HT is rich on air interface with the hole-collecting electrode. The driving force of the vertical phase separation is ascribed to the surface energy and its components of the blend compositions and the substrates. Similar results are also found with another typical alcohol soluble cathode interfacial materials, poly[(9,9-bis(3'-(N, N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN), implying that self-organization may be a general phenomenon in ternary blends. This self-organization procedure could eliminate the fabrication of printing thin film of interlayers or printing on such thin interlayers and would have potential application for roll-to-roll processing of polymer solar cells.

  11. Synthesis and characterization of cathode, anode and electrolyte materials for rechargeable lithium batteries

    NASA Astrophysics Data System (ADS)

    Yang, Shoufeng

    Two new classes of cathode materials were studied: iron phosphate/sulfate materials and layered manganese oxides, both of which are low cost and had shown some potential. The first class of materials have poor conductivity and cyclability. I studied a number of methods for increasing the conductivity, and determined that grinding the material with carbon black was as effective as special in-situ coatings. The optimum carbon loading was determined to be between 6 and 15 wt%. Too much carbon reduces the volumetric energy density, whereas too little significantly increased cell polarization (reduced the rate of reaction). The kinetic and thermodynamic stability of LiFePO 4 was also studied and it was determined that over discharge protection will be needed as irreversible Li3PO4 can be formed at low potentials. A novel hydrothermal synthesis method was developed, but the significant level of Fe on the Li site reduces the reaction rate too much. In the case of the layered manganese oxide, cation substitution with Co and Ni is found to be effective in avoiding Jahn-Teller effects and improving electrochemistry. A wide range of tin compounds have been suggested as lithium storage media for advanced anode materials, as tin can store over 4 Li per Sn atom. Lithium hexafluorophosphate, LiPF6, is presently the salt of choice for LiCoO2 batteries, but it is expensive and dissolves some manganese compounds. The lithium bis(oxolato)borate (BOB) salt was recently reported, and I made a study of its use in cells with the LiFePO4 cathode and the tin anode. During its synthesis, it became clear that LiBOB is very reactive with many solvents, and these complexes were characterized to better understand this new material. In LiBOB the lithium is five coordinated, an unstable configuration for the lithium ion so that water and many other solvents rapidly react to make a six coordination. Only in the case of ethylene carbonate was the lithium found to be four coordinated. The Li

  12. In Situ X-ray Diffraction Studies of Cathode Materials in Lithium Batteries

    SciTech Connect

    Yang, X. Q.; Sun, X.; McBreen, J.; Mukerjee, S.; Gao, Yuan; Yakovleva, M. V.; Xing, X. K.; Daroux, M. L.

    1998-11-01

    There is an increasing interest in lithiated transition metal oxides because of their use as cathodes in lithium batteries. LiCoO{sub 2}, LiNiO{sub 2} and LiMn{sub 2}O{sub 4} are the three most widely used and studied materials, At present, although it is relative expensive and toxic, LiCoO{sub 2} is the material of choice in commercial lithium ion batteries because of its ease of manufacture, better thermal stability and cycle life. However, the potential use of lithium ion batteries with larger capacity for power tools and electric vehicles in the future will demand new cathode materials with higher energy density, lower cost and better thermal stability. LiNiO{sub 2} is isostructural with LiCoO{sub 2}. It offers lower cost and high energy density than LiCoO{sub 2}. However, it has much poorer thermal stability than LiCoO{sub 2}, in the charged (delithiated) state. Co, Al, and other elements have been used to partially replace Ni in LiNiO{sub 2} system in order to increase the thermal stability. LiMn{sub 2}O{sub 4} has the highest thermal stability and lowest cost and toxicity. However, the low energy density and poor cycle life at elevated temperature are the major obstacles for this material. In order to develop safer, cheaper, and better performance cathode materials, the in-depth understanding of the relationships between the thermal stability and structure, performance and structure are very important. The performance here includes energy density and cycle life of the cathode materials. X-ray diffraction (XRD) is one of the most powerful tools to study these relationships. The pioneer ex situ XRD work on cathode materials for lithium batteries was done by Ohzuku. His XRD studies on LiMn{sub 2}O{sub 4}, LiCoO{sub 2}, LiNiO{sub 2}, LiNi{sub 0.5}Co{sub 0.5}O{sub 2}, and LiAl{sub x}Ni{sub 1-x}O{sub 2} cathodes at different states of charge have provided important guidelines for the development of these new materials. However, the kinetic nature of the battery

  13. Lithium-ion transport through a tailored disordered phase on the LiNi0.5 Mn1.5 O4 surface for high-power cathode materials.

    PubMed

    Jo, Mi Ru; Kim, Yong-Il; Kim, Yunok; Chae, Ji Su; Roh, Kwang Chul; Yoon, Won-Sub; Kang, Yong-Mook

    2014-08-01

    The phase control of spinel LiNi0.5 Mn1.5 O4 was achieved through surface treatment that led to an enhancement of its electrochemical properties. Li(+) diffusion inside spinel LiNi0.5 Mn1.5 O4 could be promoted by modifying the surface structure of LiNi0.5 Mn1.5 O4 through phosphidation into a disordered phase (Fd3m) that allows facile Li(+) transport. Phosphidated LiNi0.5 Mn1.5 O4 showed a significantly enhanced electrochemical performance, even at high rates exceeding 10 C, demonstrating that the improved kinetics (related to the amount of Mn(3+) ) can render LiNi0.5 Mn1.5 O4 competitive as a high-power cathode material for electric vehicles and hybrid electric vehicles. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Development and characterization of novel cathode materials for molten carbonate fuel cell

    NASA Astrophysics Data System (ADS)

    Giorgi, L.; Carewska, M.; Patriarca, M.; Scaccia, S.; Simonetti, E.; Dibartolomeo, A.

    1994-04-01

    In the development of molten carbonate fuel cell (MCFC) technology, the corrosion of materials is a serious problem for long-term operation. Indeed, slow dissolution of lithiated-NiO cathode in molten carbonates is the main obstacle for the commercialization of MCFCs. In the search of new, more stable, cathode materials, alternative compounds such as LiFeO2, Li2MnO3, and La(1-x)Sr(x)CoO3 are presently under investigation to replace the currently used lithiated-NiO. The aim of the present work was to investigate the possibility to produce electrode based on LiCoO2, a promising cathode material. At first, Li(x)CoO2 powder samples (0.8 less than x less than 1.1) were made by thermal decomposition of carbonate precursors in air. The synthesis processes were monitored by thermal analysis (TGA, DTA). The calcined and sintered powder samples were characterized by x ray diffraction (XRD) andatomic absorption spectrophotometry (F-AAS). A single phase was detected in all the samples, without any change in crystal structure as a function of lithium content. Porous sintered electrodes were prepared starting from lithium cobaltite powders mixed with different pore-formers by cold pressing and sintering. A bimodal pore-size distribution with a mean pore diameter in the range of 0.15 to 8 micron, a surface area of 2 to 12 sq m/g and a porosity of 10 to 65%, determined by the Hg-intrusion technique, were observed in all the materials. Conductivity measurements were carried out in the temperature range of 500-700 C, in air. The influence of the deviations from stoichiometry on the electronic properties was determined, the conductivity value of the stoichiometric compound being the lowest. A linear relationship between the electronic conductivity and the sample porosity was found. Solubility testing of the materials was carried out to evaluate their chemical stability in the electrolyte. The sampling method (F-AAS) and square wave voltammetry (SWV) were used to determine the

  15. Lithium titanate epitaxial coating on spinel lithium manganese oxide surface for improving the performance of lithium storage capability.

    PubMed

    Li, Jili; Zhu, Youqi; Wang, Lin; Cao, Chuanbao

    2014-11-12

    Spinel lithium titanate (Li4Ti5O12, LTO) is applied as an epitaxial coating layer on LiMn2O4 hollow microspheres (LMO) through solvothermal-assisted processing. The epitaxial interface between LTO and LMO can be clearly observed by high resolution transmission electron microscopy (HR-TEM) and high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) with atomic resolution images. The epitaxial coating cathode (EC-LMO@LTO) exhibits an excellent cyclability, thermal and rate capability for LIBs cathode due to the complete, thin LTO coating layer with strong adhesion to the host material. In addition, the small structure mismatch and high Li(+)-ion mobility of LTO can be beneficial to forming an efficient tunnel for Li(+)-ion transfer at the interface. It is suggested that EC-LMO@LTO can be recognized as a promising cathode material in electric vehicles (EVs) and plug-in hybrid electric vehicles (HEVs).

  16. Accelerated discovery of cathode materials with prolonged cycle life for lithium-ion battery

    NASA Astrophysics Data System (ADS)

    Nishijima, Motoaki; Ootani, Takuya; Kamimura, Yuichi; Sueki, Toshitsugu; Esaki, Shogo; Murai, Shunsuke; Fujita, Koji; Tanaka, Katsuhisa; Ohira, Koji; Koyama, Yukinori; Tanaka, Isao

    2014-08-01

    Large-scale battery systems are essential for efficiently utilizing renewable energy power sources from solar and wind, which can generate electricity only intermittently. The use of lithium-ion batteries to store the generated energy is one solution. A long cycle life is critical for lithium-ion battery when used in these applications; this is different from portable devices which require 1,000 cycles at most. Here we demonstrate a novel co-substituted lithium iron phosphate cathode with estimated 70%-capacity retention of 25,000 cycles. This is found by exploring a wide chemical compositional space using density functional theory calculations. Relative volume change of a compound between fully lithiated and delithiated conditions is used as the descriptor for the cycle life. On the basis of the results of the screening, synthesis of selected materials is targeted. Single-phase samples with the required chemical composition are successfully made by an epoxide-mediated sol-gel method. The optimized materials show excellent cycle-life performance as lithium-ion battery cathodes.

  17. Recycling of spent lithium-ion battery cathode materials by ammoniacal leaching.

    PubMed

    Ku, Heesuk; Jung, Yeojin; Jo, Minsang; Park, Sanghyuk; Kim, Sookyung; Yang, Donghyo; Rhee, Kangin; An, Eung-Mo; Sohn, Jeongsoo; Kwon, Kyungjung

    2016-08-05

    As the production and consumption of lithium ion batteries (LIBs) increase, the recycling of spent LIBs appears inevitable from an environmental, economic and health viewpoint. The leaching behavior of Ni, Mn, Co, Al and Cu from treated cathode active materials, which are separated from a commercial LIB pack in hybrid electric vehicles, is investigated with ammoniacal leaching agents based on ammonia, ammonium carbonate and ammonium sulfite. Ammonium sulfite as a reductant is necessary to enhance leaching kinetics particularly in the ammoniacal leaching of Ni and Co. Ammonium carbonate can act as a pH buffer so that the pH of leaching solution changes little during leaching. Co and Cu can be fully leached out whereas Mn and Al are hardly leached and Ni shows a moderate leaching efficiency. It is confirmed that the cathode active materials are a composite of LiMn2O4, LiCoxMnyNizO2, Al2O3 and C while the leach residue is composed of LiNixMnyCozO2, LiMn2O4, Al2O3, MnCO3 and Mn oxides. Co recovery via the ammoniacal leaching is believed to gain a competitive edge on convenitonal acid leaching both by reducing the sodium hydroxide expense for increasing the pH of leaching solution and by removing the separation steps of Mn and Al. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Theoretical investigation of pillar[4]quinone as a cathode active material for lithium-ion batteries.

    PubMed

    Huan, Long; Xie, Ju; Chen, Ming; Diao, Guowang; Zhao, Rongfang; Zuo, Tongfei

    2017-04-01

    The applicability of a novel macrocyclic multi-carbonyl compound, pillar[4]quinone (P4Q), as the cathode active material for lithium-ion batteries (LIBs) was assessed theoretically. The molecular geometry, electronic structure, Li-binding thermodynamic properties, and the redox potential of P4Q were obtained using density functional theory (DFT) at the M06-2X/6-31G(d,p) level of theory. The results of the calculations indicated that P4Q interacts with Li atoms via three binding modes: Li-O ionic bonding, O-Li···O bridge bonding, and Li···phenyl noncovalent interactions. Calculations also indicated that, during the LIB discharging process, P4Q could yield a specific capacity of 446 mAh g(-1) through the utilization of its many carbonyl groups. Compared with pillar[5]quinone and pillar[6]quinone, the redox potential of P4Q is enhanced by its high structural stability as well as the effect of the solvent. These results should provide the theoretical foundations for the design, synthesis, and application of novel macrocyclic carbonyl compounds as electrode materials in LIBs in the future. Graphical Abstract Schematic representation of the proposed charge-discharge mechanism of Pillar[4]quinone as cathode for lithium-ion batteries.

  19. Heteroaromatic organic compound with conjugated multi-carbonyl as cathode material for rechargeable lithium batteries

    PubMed Central

    Lv, Meixiang; Zhang, Fen; Wu, Yiwen; Chen, Mujuan; Yao, Chunfeng; Nan, Junmin; Shu, Dong; Zeng, Ronghua; Zeng, Heping; Chou, Shu-Lei

    2016-01-01

    The heteroaromatic organic compound, N,N’-diphenyl-1,4,5,8-naphthalenetetra- carboxylic diimide (DP-NTCDI-250) as the cathode material of lithium batteries is prepared through a simple one-pot N-acylation reaction of 1,4,5,8-naphthalenetetra-carboxylic dianhydride (NTCDA) with phenylamine (PA) in DMF solution followed by heat treatment in 250 °C. The as prepared sample is characterized by the combination of elemental analysis, NMR, FT-IR, TGA, XRD, SEM and TEM. The electrochemical measurements show that DP-NTCDI-250 can deliver an initial discharge capacity of 170 mAh g−1 at the current density of 25 mA g−1. The capacity of 119 mAh g−1 can be retained after 100 cycles. Even at the high current density of 500 mA g−1, its capacity still reaches 105 mAh g−1, indicating its high rate capability. Therefore, the as-prepared DP-NTCDI-250 could be a promising candidate as low cost cathode materials for lithium batteries. PMID:27064938

  20. Kinetic modelling of molten carbonate fuel cells: Effects of cathode water and electrode materials

    NASA Astrophysics Data System (ADS)

    Arato, E.; Audasso, E.; Barelli, L.; Bosio, B.; Discepoli, G.

    2016-10-01

    Through previous campaigns the authors developed a semi-empirical kinetic model to describe MCFC performance for industrial and laboratory simulation. Although effective in a wide range of operating conditions, the model was validated for specific electrode materials and dry feeding cathode compositions. The new aim is to prove that with appropriate improvements it is possible to apply the model to MCFC provided by different suppliers and to new sets of reactant gases. Specifically, this paper describes the procedures to modify the model to switch among different materials and identify a new parameter taking into account the effects of cathode water vapour. The new equation is integrated as the kinetic core within the SIMFC (SIMulation of Fuel Cells) code, an MCFC 3D model set up by the PERT group of the University of Genova, for reliability test. Validation is performed using data collected through tests carried out at the University of Perugia using single cells. The results are discussed giving examples of the simulated performance with varying operating conditions. The final formulation average percentage error obtained for all the simulated cases with respect to experimental results is maintained around 1%, despite the difference between the basic and the new conditions and facilities.

  1. Curly MnOx nanomembranes as cathode materials for rechargeable lithium-oxygen battery systems

    NASA Astrophysics Data System (ADS)

    Lu, Xueyi; Si, Wenping; Sun, Xiaolei; Deng, Junwen; Xi, Lixia; Liu, Bo; Yan, Chenglin; Schmidt, Oliver G.

    2015-11-01

    Two-dimensional MnOx nanomembranes prepared by electron beam evaporation are rolled up into three-dimensional hybrid micro/nano-tubes by strain release. The material is characterized with Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), cyclic voltammetry and used as the cathode catalysts for lithium-oxygen (Li-O2) batteries. The Li-O2 battery using such curly MnOx nanomembranes as the cathode delivers a specific discharge capacity of 4610 mAh gC-1 at a current density of 70 mA gC-1 which is higher than that of carbon black. Moreover, the MnOx nanomembrane electrode gains improved stability, being capable of cycling 112 times at a current density of 200 mA gC-1 . The encouraging performance is ascribed to the unique superiorities of nanomembranes and those inner oxygen vacancies, indicating that nanomembranes are promising materials for Li-O2 batteries.

  2. A mesoporous carbon–sulfur composite as cathode material for high rate lithium sulfur batteries

    SciTech Connect

    Choi, Hyunji; Zhao, Xiaohui; Kim, Dul-Sun; Ahn, Hyo-Jun; Kim, Ki-Won; Cho, Kwon-Koo; Ahn, Jou-Hyeon

    2014-10-15

    Highlights: • CMK-3 mesoporous carbon was synthesized as conducting reservoir for housing sulfur. • Sulfur/CMK-3 composites were prepared by two-stage thermal treatment. • The composite at 300 °C for 20 h shows improved electrochemical properties. - Abstract: Sulfur composite was prepared by encapsulating sulfur into CMK-3 mesoporous carbon with different heating times and then used as the cathode material for lithium sulfur batteries. Thermal treatment at 300 °C plays an important role in the sulfur encapsulation process. With 20 h of heating time, a portion of sulfur remained on the surface of carbon, whereas with 60 h of heating time, sulfur is confined deeply in the small pores of carbon that cannot be fully exploited in the redox reaction, thus causing low capacity. The S/CMK-3 composite with thermal treatment for 40 h at 300 °C contained 51.3 wt.% sulfur and delivered a high initial capacity of 1375 mA h g{sup −1} at 0.1 C. Moreover, it showed good capacity retention of 704 mA h g{sup −1} at 0.1 C and 578 mA h g{sup −1} at 2 C even after 100 cycles, which proves its potential as a cathode material for high capability lithium sulfur batteries.

  3. Preparation and performances of Co-Mn spinel coating on a ferritic stainless steel interconnect material for solid oxide fuel cell application

    NASA Astrophysics Data System (ADS)

    Zhang, H. H.; Zeng, C. L.

    2014-04-01

    Ferritic stainless steels have become the candidate materials for interconnects of intermediate temperature solid oxide fuel cell (SOFC). The present issues to be solved urgently for the application of ferritic stainless steel interconnects are their rapid increase in contact resistance and Cr poisoning. In the present study, a chloride electrolyte suspension has been developed to electro-deposit a Co-Mn alloy on a type 430 stainless steel, followed by heat treatment at 750 °C in argon and at 800 °C in air to obtain Co-Mn spinel coatings. The experimental results indicate that an adhesive and compact Co-Mn alloy layer can be deposited in the chloride solution. After heat treatment, a complex coating composed of an external MnCo2O4 layer and an inner Cr-rich oxide layer has been formed on 430SS. The coating improves the oxidation resistance of the steel at 800 °C in air, especially in wet air, and inhibits the outward diffusion of Cr from the Cr-rich scale. Moreover, a low contact resistance has been achieved with the application of the spinel coatings.

  4. Methods for using novel cathode and electrolyte materials for solid oxide fuel cells and ion transport membranes

    DOEpatents

    Jacobson, Allan J.; Wang, Shuangyan; Kim, Gun Tae

    2016-01-12

    Methods using novel cathode, electrolyte and oxygen separation materials operating at intermediate temperatures for use in solid oxide fuel cells and ion transport membranes include oxides with perovskite related structures and an ordered arrangement of A site cations. The materials have significantly faster oxygen kinetics than in corresponding disordered perovskites.

  5. Strategies to curb structural changes of lithium/transition metal oxide cathode materials & the changes’ effects on thermal & cycling stability

    NASA Astrophysics Data System (ADS)

    Xiqian, Yu; Enyuan, Hu; Seongmin, Bak; Yong-Ning, Zhou; Xiao-Qing, Yang

    2016-01-01

    Structural transformation behaviors of several typical oxide cathode materials during a heating process are reviewed in detail to provide in-depth understanding of the key factors governing the thermal stability of these materials. We also discuss applying the information about heat induced structural evolution in the study of electrochemically induced structural changes. All these discussions are expected to provide valuable insights for designing oxide cathode materials with significantly improved structural stability for safe, long-life lithium ion batteries, as the safety of lithium-ion batteries is a critical issue; it is widely accepted that the thermal instability of the cathodes is one of the most critical factors in thermal runaway and related safety problems. Project supported by the U.S. Department of Energy, the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies (Grant No. DE-SC0012704).

  6. Strategies to curb structural changes of lithium/transition metal oxide cathode materials & the changes' effects on thermal & cycling stability

    DOE PAGES

    Yu, Xiqian; Hu, Enyuan; Bak, Seongmin; ...

    2015-12-07

    Structural transformation behaviors of several typical oxide cathode materials during a heating process are reviewed in detail to provide in-depth understanding of the key factors governing the thermal stability of these materials. Furthermore, we also discuss applying the information about heat induced structural evolution in the study of electrochemically induced structural changes. All these discussions are expected to provide valuable insights for designing oxide cathode materials with significantly improved structural stability for safe, long-life lithium ion batteries, as the safety of lithium-ion batteries is a critical issue. As a result, it is widely accepted that the thermal instability of themore » cathodes is one of the most critical factors in thermal runaway and related safety problems.« less

  7. Strategies to curb structural changes of lithium/transition metal oxide cathode materials & the changes' effects on thermal & cycling stability

    SciTech Connect

    Yu, Xiqian; Hu, Enyuan; Bak, Seongmin; Zhou, Yong -Ning; Yang, Xiao -Qing

    2015-12-07

    Structural transformation behaviors of several typical oxide cathode materials during a heating process are reviewed in detail to provide in-depth understanding of the key factors governing the thermal stability of these materials. Furthermore, we also discuss applying the information about heat induced structural evolution in the study of electrochemically induced structural changes. All these discussions are expected to provide valuable insights for designing oxide cathode materials with significantly improved structural stability for safe, long-life lithium ion batteries, as the safety of lithium-ion batteries is a critical issue. As a result, it is widely accepted that the thermal instability of the cathodes is one of the most critical factors in thermal runaway and related safety problems.

  8. Li3PO4-coated LiNi0.5Mn1.5O4: a stable high-voltage cathode material for lithium-ion batteries.

    PubMed

    Chong, Jin; Xun, Shidi; Zhang, Jingping; Song, Xiangyun; Xie, Haiming; Battaglia, Vincent; Wang, Rongshun

    2014-06-10

    LiNi0.5Mn1.5O4 is regarded as a promising cathode material to increase the energy density of lithium-ion batteries due to the high discharge voltage (ca. 4.7 V). However, the interface between the LiNi0.5Mn1.5O4 cathode and the electrolyte is a great concern because of the decomposition of the electrolyte on the cathode surface at high operational potentials. To build a stable and functional protecting layer of Li3PO4 on LiNi0.5Mn1.5O4 to avoid direct contact between the active materials and the electrolyte is the emphasis of this study. Li3PO4-coated LiNi0.5Mn1.5O4 is prepared by a solid-state reaction and noncoated LiNi0.5Mn1.5O4 is prepared by the same method as a control. The materials are fully characterized by XRD, FT-IR, and high-resolution TEM. TEM shows that the Li3PO4 layer (<6 nm) is successfully coated on the LiNi0.5Mn1.5O4 primary particles. XRD and FT-IR reveal that the synthesized Li3PO4-coated LiNi0.5Mn1.5O4 has a cubic spinel structure with a space group of Fd3m, whereas noncoated LiNi0.5Mn1.5O4 shows a cubic spinel structure with a space group of P4(3)32. The electrochemical performance of the prepared materials is characterized in half and full cells. Li3PO4-coated LiNi0.5Mn1.5O4 shows dramatically enhanced cycling performance compared with noncoated LiNi0.5Mn1.5O4. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Gas evolution from cathode materials: A pathway to solvent decomposition concomitant to SEI formation.

    SciTech Connect

    Browning, Katie L; Baggetto, Loic; Unocic, Raymond R; Dudney, Nancy J; Veith, Gabriel M

    2013-01-01

    This work reports a method to explore the catalytic reactivity of electrode surfaces towards the decomposition of carbonate solvents [ethylene carbonate (EC), dimethyl carbonate (DMC), and EC/DMC]. We show that the decomposition of a 1:1 wt% EC/DMC mixture is accelerated over certain commercially available LiCoO2 materials resulting in the formation of CO2 while over pure EC or DMC the reaction is much slower or negligible. The solubility of the produced CO2 in carbonate solvents is high (0.025 grams/mL) which masks the effect of electrolyte decomposition during storage or use. The origin of this decomposition is not clear but it is expected to be present on other cathode materials and may affect the analysis of SEI products as well as the safety of Li-ion batteries.

  10. Review on electrode-electrolyte solution interactions, related to cathode materials for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Aurbach, Doron; Markovsky, Boris; Salitra, Gregory; Markevich, Elena; Talyossef, Yossi; Koltypin, Maxim; Nazar, Linda; Ellis, Brian; Kovacheva, Daniella

    In this paper we review some critical aspects related to interactions between cathode materials and electrolyte solutions in lithium-ion batteries. Previous results are briefly summarized, together with the presentation of new results. This review deals with the basic anodic stability of commonly-used electrolyte solutions for Li-ion batteries (mostly based on alkyl carbonate solvents). We discuss herein the surface chemistry of the following cathode materials: LiCoO 2, V 2O 5, LiMn 2O 4, LiMn 1.5Ni 0.5O 4, LiMn 0.5Ni 0.5O 2, and LiFePO 4. The methods applied included solution studies by ICP, Raman, X-ray photoelectron and FTIR spectroscopies, and electron microscopy, all in conjunction with electrochemical techniques. General phenomena are the possible dissolution of transition metal ions from these materials, which leads to changes in the active mass and a retardation in the electrode kinetics due to the formation of blocking surface films. These phenomena are significant mostly at elevated temperatures and in electrolyte solutions containing acidic species. Water-contaminated LiPF 6 solutions can reach a high concentration of acidic species (e.g., HF), which is detrimental to the performance of materials such as LiCoO 2 and LiFePO 4. Both LiMn 1.5Ni 0.5O 4 and LiMn 0.5Ni 0.5O 2, even when used as nanomaterials, show a high stability in commonly-used electrolyte solutions at high temperatures. This stability is attributed to unique surface chemistry that is correlated to the presence of Ni ions in the lattice.

  11. Study of LiFePO 4 cathode materials coated with high surface area carbon

    NASA Astrophysics Data System (ADS)

    Lu, Cheng-Zhang; Fey, George Ting-Kuo; Kao, Hsien-Ming

    LiFePO 4 is a potential cathode material for 4 V lithium-ion batteries. Carbon-coated lithium iron phosphates were prepared using a high surface area carbon to react precursors through a solid-state process, during which LiFePO 4 particles were embedded in amorphous carbon. The carbonaceous materials were synthesized by the pyrolysis of peanut shells under argon, where they were carbonized in a two-step process that occurred between 573 and 873 K. The shells were also treated with a proprietary porogenic agent with the goal of altering the pore structure and surface area of the pyrolysis products. The electrochemical properties of the as-prepared LiFePO 4/C composite cathode materials were systematically characterized by X-ray diffraction, scanning electron microscope, element mapping, energy dispersive spectroscopy, Raman spectroscopy, and total organic carbon (TOC) analysis. In LiFePO 4/C composites, the carbon not only increases rate capability, but also stabilizes capacity. In fact, the capacity of the composites increased with the specific surface area of carbon. The best result was observed with a composite made of 8.0 wt.% with a specific surface area of 2099 m 2 g -1. When high surface area carbon was used as a carbon source to produce LiFePO 4, overall conductivity increased from 10 -8 to 10 -4 S cm -1, because the inhibition of particle growth during the final sintering process led to greater specific capacity, improved cycling properties and better rate capability compared to a pure olivine LiFePO 4 material.

  12. Effect of cathode material on the electrorefining of U in LiCl-KCl molten salts

    NASA Astrophysics Data System (ADS)

    Lee, Chang Hwa; Kim, Tack-Jin; Park, Sungbin; Lee, Sung-Jai; Paek, Seung-Woo; Ahn, Do-Hee; Cho, Sung-Ki

    2017-05-01

    The influence of cathode materials on the U electrorefining process is examined using electrochemical measurements and SEM-EDX observations. Stainless steel (STS), Mo, and W electrodes exhibit similar U reduction/oxidation behavior in 500 °C LiCl-KCl-UCl3 molten salts, as revealed by the cyclic voltammograms. However, slight shifts are observed in the cathodic and anodic peak potentials at the STS electrode, which are related to the fast reduction/oxidation kinetics associated with this electrode. The U deposits on the Mo and W electrodes consist of uniform dendritic chains of U in rhomboidal-shaped crystals, whereas several U dendrites protruding from the surface are observed for the STS electrode. EDX mapping of the electrode surfaces reveals that simple scraping of the U dendrites from W electrodes pretreated in dilute HCl solutions to dissolve the residual salt, results in clear removal of the U deposits, whereas a thick U deposit layer strongly adheres to the STS electrode surface even after treatment. This result is expected to contribute to the development of an effective and continuous U recovery process using electrorefining.

  13. Recent advances in first principles computational research of cathode materials for lithium-ion batteries.

    PubMed

    Meng, Ying Shirley; Arroyo-de Dompablo, M Elena

    2013-05-21

    To meet the increasing demands of energy storage, particularly for transportation applications such as plug-in hybrid electric vehicles, researchers will need to develop improved lithium-ion battery electrode materials that exhibit high energy density, high power, better safety, and longer cycle life. The acceleration of materials discovery, synthesis, and optimization will benefit from the combination of both experimental and computational methods. First principles (ab Initio) computational methods have been widely used in materials science and can play an important role in accelerating the development and optimization of new energy storage materials. These methods can prescreen previously unknown compounds and can explain complex phenomena observed with these compounds. Intercalation compounds, where Li(+) ions insert into the host structure without causing significant rearrangement of the original structure, have served as the workhorse for lithium ion rechargeable battery electrodes. Intercalation compounds will also facilitate the development of new battery chemistries such as sodium-ion batteries. During the electrochemical discharge reaction process, the intercalating species travel from the negative to the positive electrode, driving the transition metal ion in the positive electrode to a lower oxidation state, which delivers useful current. Many materials properties change as a function of the intercalating species concentrations (at different state of charge). Therefore, researchers will need to understand and control these dynamic changes to optimize the electrochemical performance of the cell. In this Account, we focus on first-principles computational investigations toward understanding, controlling, and improving the intrinsic properties of five well known high energy density Li intercalation electrode materials: layered oxides (LiMO2), spinel oxides (LiM2O4), olivine phosphates (LiMPO4), silicates-Li2MSiO4, and the tavorite-LiM(XO4)F (M = 3d

  14. Investigation on preparation and performance of spinel LiNi0.5Mn1.5O4 with different microstructures for lithium-ion batteries.

    PubMed

    Xue, Yuan; Wang, Zhenbo; Zheng, Lili; Yu, Fuda; Liu, Baosheng; Zhang, Yin; Ke, Ke

    2015-08-24

    The high voltage spinel LiNi0.5Mn1.5O4 is a promising cathode material in next generation of lithium ion batteries. In this study, LiNi0.5Mn1.5O4 with various particle microstructures are prepared by controlling the microstructures of precursors. LiNi0.5Mn1.5O4 spinel samples with solid, hollow and hierarchical microstructures are prepared with solid MnCO3, hollow MnO2 and hierarchical Mn2O3 as precursor, respectively. The homemade spinel materials are investigated and the results show that the content of Mn(3+) and impurity phase differ much in these three spinel samples obtained under the same calcining and annealing conditions. It is revealed for the first time that an inhomogeneous migration of atoms may introduce Mn(3+) and impurity phase in the spinel. The hierarchical microstructure with the primary particles interconnected is optimal for electrode materials because this microstructure has a higher conductivity between the interconnected primary particles and appropriate specific surface area. LiNi0.5Mn1.5O4 in this microstructure has the best rate capability and also the best long-term cycling stability.

  15. Specially designed carbon black nanoparticle-sulfur composite cathode materials with a novel structure for lithium-sulfur battery application

    NASA Astrophysics Data System (ADS)

    Sun, Zhenjie; Xiao, Min; Wang, Shuanjin; Han, Dongmei; Song, Shuqin; Chen, Guohua; Meng, Yuezhong

    2015-07-01

    Sulfur is a promising cathode material with a high theoretical capacity of 1672 mAh g-1, but the challenges of the low electrical conductivity of sulfur and the high solubility of polysulfide intermediates still hinder its practical application. In this work, we design and synthesize a special carbon black nanoparticle-sulfur composite cathode material (NCB-S@NCB) with a novel structure and a high sulfur content of 84 wt% for lithium-sulfur battery application. The NCB-S@NCB composite cathode delivers a high initial discharge capacity of 1258 mAh g-1 and still maintains a reversible capacity of 865 mAh g-1 after 100 cycles with a relatively constant Coulombic efficiency around 98.0%.

  16. Structural and Electrical Properties of Lithium-Ion Rechargeable Battery Using the LiFePO4/Carbon Cathode Material.

    PubMed

    Kim, Young-Sung; Jeoung, Tae-Hoon; Nam, Sung-Pill; Lee, Seung-Hwan; Kim, Jea-Chul; Lee, Sung-Gap

    2015-03-01

    LiFePO4/C composite powder as cathode material and graphite powder as anode material for Li-ion batteries were synthesized by using the sol-gel method. An electrochemical improvement of LiFePO4 materials has been achieved by adding polyvinyl alcohol as a carbon source into as-prepared materials. The samples were characterized by elemental analysis (EA), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-EM). The chemical composition of LiFePO4/C powders was in a good agreement with that of the starting solution. The capacity loss after 500 cycles of LiFePO4/C cell is 11.1% in room temperature. These superior electrochemical properties show that LiFePO4/C composite materials are promising candidates as cathode materials.

  17. Impact of ALD Coating on Mn-rich Cathode Materials (Presentation)

    SciTech Connect

    Santhanagopalan, S.

    2013-06-01

    LG Chem Power Inc. (LGCPI) and NREL have collaborated to demonstrate the scalability of the atomic layer deposition (ALD) coating process over the last 6 months, and the benefits of ALD coatings for long-term cycling and calendar life are being quantified. The objectives of this work are two-fold: 1) to evaluate the scalability of the process to coat LGCPI cathodes with alumina using the ALD technique, and 2) to demonstrate improvements in rate capability and life of ALD-coated LGCPI electrodes. NREL received samples of baseline material to be coated from LGCPI. NREL carried out ALD coating of the samples with help from a subcontractor, ALD Nanosolutions. NREL fabricated cells from those samples for quick screening and feedback to ALD Nanosolutions. LGCPI is currently fabricating larger-format cells for further evaluation.

  18. Suppressing the voltage-fading of layered lithium-rich cathode materials via an aqueous binder for Li-ion batteries.

    PubMed

    Zhang, Tao; Li, Jun-tao; Liu, Jie; Deng, Ya-ping; Wu, Zhen-guo; Yin, Zu-wei; Guo, Dong; Huang, Ling; Sun, Shi-gang

    2016-03-28

    Guar gum (GG) has been applied as a binder for layered lithium-rich cathode materials of Li-ion batteries for the first time. Compared with the conventional PVDF binder, electrodes with GG as the binder exhibit significantly suppressed voltage and capacity fading. This study has introduced a multi-functional binder for layered lithium-rich cathode materials.

  19. Evolution of lattice structure and chemical composition of the surface reconstruction layer in Li(1.2)Ni(0.2)Mn(0.6)O2 cathode material for lithium ion batteries.

    PubMed

    Yan, Pengfei; Nie, Anmin; Zheng, Jianming; Zhou, Yungang; Lu, Dongping; Zhang, Xiaofeng; Xu, Rui; Belharouak, Ilias; Zu, Xiaotao; Xiao, Jie; Amine, Khalil; Liu, Jun; Gao, Fei; Shahbazian-Yassar, Reza; Zhang, Ji-Guang; Wang, Chong-Min

    2015-01-14

    Voltage and capacity fading of layer structured lithium and manganese rich (LMR) transition metal oxide is directly related to the structural and composition evolution of the material during the cycling of the battery. However, understanding such evolution at atomic level remains elusive. On the basis of atomic level structural imaging, elemental mapping of the pristine and cycled samples, and density functional theory calculations, it is found that accompanying the hoping of Li ions is the simultaneous migration of Ni ions toward the surface from the bulk lattice, leading to the gradual depletion of Ni in the bulk lattice and thickening of a Ni enriched surface reconstruction layer (SRL). Furthermore, Ni and Mn also exhibit concentration partitions within the thin layer of SRL in the cycled samples where Ni is almost depleted at the very surface of the SRL, indicating the preferential dissolution of Ni ions in the electrolyte. Accompanying the elemental composition evolution, significant structural evolution is also observed and identified as a sequential phase transition of C2/m → I41 → Spinel. For the first time, it is found that the surface facet terminated with pure cation/anion is more stable than that with a mixture of cation and anion. These findings firmly established how the elemental species in the lattice of LMR cathode transfer from the bulk lattice to surface layer and further into the electrolyte, clarifying the long-standing confusion and debate on the structure and chemistry of the surface layer and their correlation with the voltage fading and capacity decaying of LMR cathode. Therefore, this work provides critical insights for design of cathode materials with both high capacity and voltage stability during cycling.

  20. Evolution Of Lattice Structure And Chemical Composition Of The Surface Reconstruction Layer In Li1.2Ni0.2Mn0.6O2 Cathode Material For Lithium Ion Batteries

    SciTech Connect

    Yan, Pengfei; Nie, Anmin; Zheng, Jianming; Zhou, Yungang; Lu, Dongping; Zhang, Xiaofeng; Xu, Rui; Belharouak, Ilias; Zu, Xiaotao; Xiao, Jie; Amine, Khalil; Liu, Jun; Gao, Fei; Shahbazian-Yassar, Reza; Zhang, Jiguang; Wang, Chong M.

    2015-01-14

    Voltage and capacity fading of layer structured lithium and manganese rich (LMR) transition metal oxide is directly related to the structural and composition evolution of the material during the cycling of the battery. However, understanding such evolution at atomic level remains elusive. Based on atomic level structural imaging, elemental mapping of the pristine and cycled samples and density functional theory calculations, it is found that accompanying the hoping of Li ions is the simultaneous migration of Ni ions towards the surface from the bulk lattice, leading to the gradual depletion of Ni in the bulk lattice and thickening of a Ni enriched surface reconstruction layer (SRL). Furthermore, Ni and Mn also exhibit concentration partitions within the thin layer of SRL in the cycled samples where Ni is almost depleted at the very surface of the SRL, indicating the preferential dissolution of Ni ions in the electrolyte. Accompanying the elemental composition evolution, significant structural evolution is also observed and identified as a sequential phase transition of C2/m →I41→Spinel. For the first time, it is found that the surface facet terminated with pure cation is more stable than that with a mixture of cation and anion. These findings firmly established how the elemental species in the lattice of LMR cathode transfer from the bulk lattice to surface layer and further into the electrolyte, clarifying the long standing confusion and debate on the structure and chemistry of the surface layer and their correlation with the voltage fading and capacity decaying of LMR cathode. Therefore, this work provides critical insights for designing of cathode materials with both high capacity and voltage stability during cycling.

  1. Advanced carbon materials/olivine LiFePO4 composites cathode for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Gong, Chunli; Xue, Zhigang; Wen, Sheng; Ye, Yunsheng; Xie, Xiaolin

    2016-06-01

    In the past two decades, LiFePO4 has undoubtly become a competitive candidate for the cathode material of the next-generation LIBs due to its abundant resources, low toxicity and excellent thermal stability, etc. However, the poor electronic conductivity as well as low lithium ion diffusion rate are the two major drawbacks for the commercial applications of LiFePO4 especially in the power energy field. The introduction of highly graphitized advanced carbon materials, which also possess high electronic conductivity, superior specific surface area and excellent structural stability, into LiFePO4 offers a better way to resolve the issue of limited rate performance caused by the two obstacles when compared with traditional carbon materials. In this review, we focus on advanced carbon materials such as one-dimensional (1D) carbon (carbon nanotubes and carbon fibers), two-dimensional (2D) carbon (graphene, graphene oxide and reduced graphene oxide) and three-dimensional (3D) carbon (carbon nanotubes array and 3D graphene skeleton), modified LiFePO4 for high power lithium ion batteries. The preparation strategies, structure, and electrochemical performance of advanced carbon/LiFePO4 composite are summarized and discussed in detail. The problems encountered in its application and the future development of this composite are also discussed.

  2. Hydroxyl-decorated Graphene Systems: Organic metal-free Ferroelectrics, Multiferroics, and Proton battery Cathode Materials

    NASA Astrophysics Data System (ADS)

    Wu, Menghao; Burton, J. D.; Tsymbal, Evgeny; Zeng, Xiao; Jena, Puru; Jena's Group Team, Prof.; Burton's Group Team, Prof.; Tsymbal's Group Team, Prof.; Zeng's Group Team, Prof.

    2013-03-01

    Through density-functional-theory calculations we show that hydroxylized graphene systems are ideal candidates for light-weight organic ferroelectric materials with giant polarizations. For example, the polarization of semi-hydroxylized graphane and graphone as well as fully hydroxylized graphane are, respectively, 41.1, 43.7, 67.7 μC/cm2, much higher than any organic ferroelectric materials known to date. In addition, hydroxylized graphone is multiferroic due to the coexistence of ferroeletricity and ferromagnetism. Zigzag graphene nanoribbons decorated by hydroxyl groups also exhibit ferroelectric properties with a large polarization of 27.0 μC/cm2. Moreover, proton vacancies at the end of ribbons can induce large dipole moments that can be reversed by both hopping of protons and rotation of O-H bonds under an electric field. These materials have the potential as high-capacity cathode materials with specific capacity six times larger than lead-acid batteries and five times that of lithium-ion batteries.

  3. Variations in structure and electrochemistry of iron- and titanium-doped lithium nickel manganese oxyfluoride spinels

    NASA Astrophysics Data System (ADS)

    Höweling, Andres; Stenzel, David; Gesswein, Holger; Kaus, Maximilian; Indris, Sylvio; Bergfeldt, Thomas; Binder, Joachim R.

    2016-05-01

    Doping of cathode materials can considerably improve electrochemical performance and stability. Here, the high-voltage LiNi0.5Mn1.5O4 spinel is used as a candidate material. It is high-voltage cycling at a potential of approximately 4.7 V and the ability to host 2 eq. Li, thus leading to a theoretical capacity of 294 mAh g-1, that makes this material interesting. In order to improve stability and electronic conductivity, the spinel is doped with titanium and iron. Cycling in a voltage range of 2.0-5.0 V leads to a cooperative Jahn-Teller distortion accompanied by a phase transformation from cubic to tetragonal symmetry. This causes a severe capacity fade. To improve capacity retention, the as-prepared spinel is post-doped with fluorine. Influence of different fluorine amounts in LiNi0.5Mn1.4Fe0.1Ti0.027O4-xFx (x = 0-0.3) on the capacity and stability is analyzed. The initial capacities decrease with increasing fluorine content but the low voltage capacity is stabilized. Best electrochemical results are obtained with a fluorine content of x = 0.15. Furthermore, an additional redox couple is found. The intensity of this depends on the fluorine content. It is assumed that manganese, either in the tetrahedral sites or in octahedral sites, bound to fluorine lead to a higher voltage.

  4. Sodium iron hexacyanoferrate with high Na content as a Na-rich cathode material for Na-ion batteries

    SciTech Connect

    You, Ya; Yu, Xi -Qian; Yin, Ya -Xia; Nam, Kyung -Wan; Guo, Yu -Guo

    2014-10-27

    Owing to the worldwide abundance and low-cost of Na, room-temperature Na-ion batteries are emerging as attractive energy storage systems for large-scale grids. Increasing the Na content in cathode material is one of the effective ways to achieve high energy density. Prussian blue and its analogues (PBAs) are promising Na-rich cathode materials since they can theoretically store two Na ions per formula. However, increasing the Na content in PBAs cathode materials is a big challenge in the current. Here we show that sodium iron hexacyanoferrate with high Na content could be obtained by simply controlling the reducing agent and reaction atmosphere during synthesis. The Na content can reach as high as 1.63 per formula, which is the highest value for sodium iron hexacyanoferrate. This Na-rich sodium iron hexacyanoferrate demonstrates a high specific capacity of 150 mA h g-1 and remarkable cycling performance with 90% capacity retention after 200 cycles. Furthermore, the Na intercalation/de-intercalation mechanism is systematically studied by in situ Raman, X-ray diffraction and X-ray absorption spectroscopy analysis for the first time. As a result, the Na-rich sodium iron hexacyanoferrate could function as a plenteous Na reservoir and has great potential as a cathode material toward practical Na-ion batteries.

  5. Sodium iron hexacyanoferrate with high Na content as a Na-rich cathode material for Na-ion batteries

    DOE PAGES

    You, Ya; Yu, Xi -Qian; Yin, Ya -Xia; ...

    2014-10-27

    Owing to the worldwide abundance and low-cost of Na, room-temperature Na-ion batteries are emerging as attractive energy storage systems for large-scale grids. Increasing the Na content in cathode material is one of the effective ways to achieve high energy density. Prussian blue and its analogues (PBAs) are promising Na-rich cathode materials since they can theoretically store two Na ions per formula. However, increasing the Na content in PBAs cathode materials is a big challenge in the current. Here we show that sodium iron hexacyanoferrate with high Na content could be obtained by simply controlling the reducing agent and reaction atmospheremore » during synthesis. The Na content can reach as high as 1.63 per formula, which is the highest value for sodium iron hexacyanoferrate. This Na-rich sodium iron hexacyanoferrate demonstrates a high specific capacity of 150 mA h g-1 and remarkable cycling performance with 90% capacity retention after 200 cycles. Furthermore, the Na intercalation/de-intercalation mechanism is systematically studied by in situ Raman, X-ray diffraction and X-ray absorption spectroscopy analysis for the first time. As a result, the Na-rich sodium iron hexacyanoferrate could function as a plenteous Na reservoir and has great potential as a cathode material toward practical Na-ion batteries.« less

  6. Computational Screening for Design of Optimal Coating Materials to Suppress Gas Evolution in Li-Ion Battery Cathodes.

    PubMed

    Min, Kyoungmin; Seo, Seung-Woo; Choi, Byungjin; Park, Kwangjin; Cho, Eunseog

    2017-05-31

    Ni-rich layered oxides are attractive materials owing to their potentially high capacity for cathode applications. However, when used as cathodes in Li-ion batteries, they contain a large amount of Li residues, which degrade the electrochemical properties because they are the source of gas generation inside the battery. Here, we propose a computational approach to designing optimal coating materials that prevent gas evolution by removing residual Li from the surface of the battery cathode. To discover promising coating materials, the reactions of 16 metal phosphates (MPs) and 45 metal oxides (MOs) with the Li residues, LiOH, and Li2CO3 are examined within a thermodynamic framework. A materials database is constructed according to density functional theory using a hybrid functional, and the reaction products are obtained according to the phases in thermodynamic equilibrium in the phase diagram. In addition, the gravimetric efficiency is calculated to identify coating materials that can eliminate Li residues with a minimal weight of the coating material. Overall, more MP and MO materials react with LiOH than with Li2CO3. Specifically, MPs exhibit better reactivity to both Li residues, whereas MOs react more with LiOH. The reaction products, such as Li-containing phosphates or oxides, are also obtained to identify the phases on the surface of a cathode after coating. On the basis of the Pareto-front analysis, P2O5 could be an optimal material for the reaction with both Li residuals. Finally, the reactivity of the coating materials containing 3d/4d transition metal elements is better than that of materials containing other types of elements.

  7. Investigating the stability of cathode materials for rechargeable lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Huang, Yiqing

    Lithium ion batteries are widely used in portable electronic devices and electric vehicles. However, safety is one of the most important issues for the Li-ion batteries' use. Some cathode materials, such as LiCoO 2, are thermally unstable in the charged state. Upon decomposition these cathode materials release O2, which could react with organic electrolyte, leading to a thermal runaway. Thus understanding the stability of the cathode materials is critical to the safety of lithium ion batteries. Olivine-type LiMnPO4 is a promising cathode material for lithium ion batteries because of its high energy density. We have revealed the critical role of carbon in the stability and thermal behaviour of olivine MnPO 4 obtained by chemical delithiation of LiMnPO4. (Li)MnPO 4 samples with various particle sizes and carbon contents were studied. Carbon-free LiMnPO4 obtained by solid state synthesis in O 2 becomes amorphous upon delithiation. Small amounts of carbon (0.3 wt.%) help to stabilize the olivine structure, so that completely delithiated crystalline olivine MnPO4 can be obtained. Larger amount of carbon (2 wt.%) prevents full delithiation. Heating in air, O2, or N 2 results in structural disorder (< 300 °C), formation of an intermediate sarcopside Mn3(PO4)2 phase (350 -- 450 °C), and complete decomposition to Mn2P2O 7 on extended heating at 400 °C. Carbon protects MnPO4 from reacting with environmental water, which is detrimental to its structural stability. We not only studied the crystalline olivine MnPO4, but also investigated the amorphous products obtained from carbon-free LiMnPO 4. We have revealed the Mn dissolution phenomenon during chemical delithiation of LiMnPO4, which causes the amorphization of olivine MnPO 4. Properties of crystalline-MnPO4 obtained from carbon-coated LiMnPO4 and of amorphous product resulting from the delithiation of pure LiMnPO4 were studied and compared. The P-rich amorphous phases in the latter are considered to be MnHP2O7 and MnH2P

  8. Characterization and electrochemical activities of nanostructured transition metal nitrides as cathode materials for lithium sulfur batteries

    NASA Astrophysics Data System (ADS)

    Mosavati, Negar; Salley, Steven O.; Ng, K. Y. Simon

    2017-02-01

    The Lithium Sulfur (Li-S) battery system is one of the most promising candidates for electric vehicle applications due to its higher energy density when compared to conventional lithium ion batteries. However, there are some challenges facing Li-S battery commercialization, such as: low active material utilization, high self-discharge rate, and high rate of capacity fade. In this work, a series of transition metal nitrides: Tungsten nitride (WN), Molybdenum Nitride (Mo2N), and Vanadium Nitride (VN) was investigated as cathode materials for lithium polysulfide conversion reactions. Capacities of 697, 569, and 264 mAh g-1 were observed for WN, Mo2N, VN, respectively, with 8 mg cm-2 loading, after 100 cycles at a 0.1 C rate. WN higher electrochemical performance may be attributed to a strong reversible reaction between nitrides and polysulfide, which retains the sulfur species on the electrode surface, and minimizes the active material and surface area loss. X-ray photoelectron spectroscopy (XPS) analysis was performed to gain a better understanding of the mechanism underlying each metal nitride redox reactions.

  9. Depression cathode structure for cathode ray tubes having surface smoothness and method for producing same

    SciTech Connect

    Rychlewski, T.V.

    1984-10-23

    Depression cathode structures for cathode ray tubes are produced by dispensing liquid cathode material into the depression of a metallic supporting substrate, removing excess cathode material by passing a doctor blade across the substrate surface and over the depression, and drying the cathode layer to a substantially immobile state. The cathode layer may optionally be further shaped prior to substantially complete drying thereof.

  10. Sintered wire cathode

    DOEpatents

    Falce, Louis R.; Ives, R. Lawrence

    2009-06-09

    A porous cathode structure is fabricated from a plurality of wires which are placed in proximity to each other in elevated temperature and pressure for a sintering time. The sintering process produces the porous cathode structure which may be divided into a plurality of individual porous cathodes, one of which may be placed into a dispenser cathode support which includes a cavity for containing a work function reduction material such as BaO, CaO, and Al.sub.2O.sub.3. The work function reduction material migrates through the pores of the porous cathode from a work replenishment surface adjacent to the cavity of the dispenser cathode support to an emitting cathode surface, thereby providing a dispenser cathode which has a uniform work function and therefore a uniform electron emission.

  11. Pulse combustion reactor as a fast and scalable synthetic method for preparation of Li-ion cathode materials

    NASA Astrophysics Data System (ADS)

    Križan, Gregor; Križan, Janez; Dominko, Robert; Gaberšček, Miran

    2017-09-01

    In this work a novel pulse combustion reactor method for preparation of Li-ion cathode materials is introduced. Its advantages and potential challenges are demonstrated on two widely studied cathode materials, LiFePO4/C and Li-rich NMC. By exploiting the nature of efficiency of pulse combustion we have successfully established a slightly reductive or oxidative environment necessary for synthesis. As a whole, the proposed method is fast, environmentally friendly and easy to scale. An important advantage of the proposed method is that it preferentially yields small-sized powders (in the nanometric range) at a fast production rate of 2 s. A potential disadvantage is the relatively high degree of disorder of synthesized active material which however can be removed using a post-annealing step. This additional step allows a further tuning of materials morphology as shown and commented in some detail.

  12. Surface Heterostructure Induced by PrPO4 Modification in Li1.2[Mn0.54Ni0.13Co0.13]O2 Cathode Material for High-Performance Lithium-Ion Batteries with Mitigating Voltage Decay.

    PubMed

    Ding, Feixiang; Li, Jianling; Deng, Fuhai; Xu, Guofeng; Liu, Yanying; Yang, Kai; Kang, Feiyu

    2017-08-23

    Lithium-rich layered oxides (LLOs) have been attractive cathode materials for lithium-ion batteries because of their high reversible capacity. However, they suffer from low initial Coulombic efficiency and capacity/voltage decay upon cycling. Herein, facile surface modification of Li1.2Mn0.54Ni0.13Co0.13O2 cathode material is designed to overcome these defects by the protective effect of a surface heterostructure composed of an induced spinel layer and a PrPO4 modification layer. As anticipated, a sample modified with 3 wt % PrPO4 (PrP3) shows an enhanced initial Coulombic efficiency of 90% compared to 81.8% for the pristine one, more excellent cycling stability with a capacity retention of 89.3% after 100 cycles compared to only 71.7% for the pristine one, and less average discharge voltage fading from 0.6353 to 0.2881 V. These results can be attributed to the fact that the modification nanolayers have moved amounts of oxygen and lithium from the lattice in the bulk crystal structure, leading to a chemical activation of the Li2MnO3 component previously and forming a spinel interphase with a 3D fast Li(+) diffusion channel and stable structure. Moreover, the elaborate surface heterostructure on a lithium-rich cathode material can effectively curb the undesired side reactions with the electrolyte and may also extend to other layered oxides to improve their cycling stability at high voltage.

  13. Facet Dependent Disorder in the Pristine High Voltage Lithium-Manganese-Rich Cathode Material

    SciTech Connect

    Dixit, Hemant M.; Zhou, Wu; Idrobo Tapia, Juan Carlos; Nanda, Jagjit; Cooper, Valentino R.

    2014-11-21

    Defects and surface reconstructions are thought to be crucial for the long term stability of high-voltage lithium-manganese-rich cathodes. Unfortunately, many of these defects arise only after electrochemical cycling which occur under harsh conditions making it difficult to fully comprehend the role they play in degrading material performance. Recently, it has been observed that defects are present even in the pristine material. This study, therefore, focuses on examining the nature of the disorder observed in pristine Li$_{1.2}$Ni$_{0.175}$Mn$_{0.525}$Co$_{0.1}$O$_2$ (LNMCO) particles. Using atomic resolution Z-contrast imaging and electron energy-loss spectroscopy measurements we show that there are indeed a significant amount of anti-site defects present in this material; with transition metals substituting on Li metal sites. Furthermore, we find a strong tendency of segregation of these types of defects towards open facets (surfaces perpendicular to the layered arrangement of atoms), rather than closed facets (surfaces parallel to the layered arrangement of atoms). First principles calculations identify anti-site defect pairs of Ni swapping with Li ions as the predominant defect in the material. Furthermore, energetically favorable swapping of Ni on the Mn sites were observed to lead to Mn depletion at open facets. Relatively, low Ni migration barriers also support the notion that Ni are the predominant cause of disorder. These insights suggests that certain facets of the LNMCO particles may be more useful for inhibiting surface reconstruction and improving the stability of these materials through careful consideration of the exposed surface.

  14. Facet Dependent Disorder in the Pristine High Voltage Lithium-Manganese-Rich Cathode Material

    DOE PAGES

    Dixit, Hemant M.; Zhou, Wu; Idrobo Tapia, Juan Carlos; ...

    2014-11-21

    Defects and surface reconstructions are thought to be crucial for the long term stability of high-voltage lithium-manganese-rich cathodes. Unfortunately, many of these defects arise only after electrochemical cycling which occur under harsh conditions making it difficult to fully comprehend the role they play in degrading material performance. Recently, it has been observed that defects are present even in the pristine material. This study, therefore, focuses on examining the nature of the disorder observed in pristine Limore » $$_{1.2}$$Ni$$_{0.175}$$Mn$$_{0.525}$$Co$$_{0.1}$$O$$_2$$ (LNMCO) particles. Using atomic resolution Z-contrast imaging and electron energy-loss spectroscopy measurements we show that there are indeed a significant amount of anti-site defects present in this material; with transition metals substituting on Li metal sites. Furthermore, we find a strong tendency of segregation of these types of defects towards open facets (surfaces perpendicular to the layered arrangement of atoms), rather than closed facets (surfaces parallel to the layered arrangement of atoms). First principles calculations identify anti-site defect pairs of Ni swapping with Li ions as the predominant defect in the material. Furthermore, energetically favorable swapping of Ni on the Mn sites were observed to lead to Mn depletion at open facets. Relatively, low Ni migration barriers also support the notion that Ni are the predominant cause of disorder. These insights suggests that certain facets of the LNMCO particles may be more useful for inhibiting surface reconstruction and improving the stability of these materials through careful consideration of the exposed surface.« less

  15. Facet-dependent disorder in pristine high-voltage lithium-manganese-rich cathode material.

    PubMed

    Dixit, Hemant; Zhou, Wu; Idrobo, Juan-Carlos; Nanda, Jagjit; Cooper, Valentino R

    2014-12-23

    Defects and surface reconstructions are thought to be crucial for the long-term stability of high-voltage lithium-manganese-rich cathodes. Unfortunately, many of these defects arise only after electrochemical cycling which occurs under harsh conditions, making it difficult to fully comprehend the role they play in degrading material performance. Recently, it has been observed that defects are present even in the pristine material. This study, therefore, focuses on examining the nature of the disorder observed in pristine Li1.2Ni0.175Mn0.525Co0.1O2 (LNMCO) particles. Using atomic-resolution Z-contrast imaging and electron energy loss spectroscopy measurements, we show that there is indeed a significant amount of antisite defects present in this material, with transition metals substituting on Li metal sites. Furthermore, we find a strong segregation tendency of these types of defects toward open facets (surfaces perpendicular to the layered arrangement of atoms) rather than closed facets (surfaces parallel to the layered arrangement of atoms). First-principles calculations identify antisite defect pairs of Ni swapping with Li ions as the predominant defect in the material. Furthermore, energetically favorable swapping of Ni on the Mn sites was observed to lead to Mn depletion at open facets. Relatively, low Ni migration barriers also support the notion that Ni is the predominant cause of disorder. These insights suggest that certain facets of the LNMCO particles may be more useful for inhibiting surface reconstruction and improving the stability of these materials through careful consideration of the exposed surface.

  16. Evolution of Phase Transformation Behavior in Li(Mn1.5Ni0.5)O4 Cathodes Studies By In Situ XRD

    SciTech Connect

    Rhodes, Kevin J; Meisner, Roberta Ann; Kim, Yoongu; Dudney, Nancy J; Daniel, Claus

    2011-01-01

    Li(Mn1.5Ni0.5)O4 (MNO) is promising spinel cathode material for lithium ion batteries (LIB) due to its increased intercalation potential and improved capacity retention compared to LiMn2O4. Still, improvements to this materials performance must be achieved before MNO is a viable option for commercial LIB cells. In situ X-ray diffraction of Li(Mn1.5Ni0.5)O4 was performed using a novel electrochemical cell based on coin cell hardware. A diffractogram of the pristine material showed a spinel structure with a Ni2+ oxidation state. As the cell was charged through its 4.75V plateau, a transition between spinels with Ni2+, Ni3+, and Ni4+ oxidation was observed. As the oxidation stage on the nickel increased the lattice parameter of the corresponding spinel was reduced. As discharged ensued the spinel reversed its phases change until only the Ni2+ spinel was present. When discharge reached the 2.75V plateau a tetragonal spinel phase was formed, which upon subsequent cell charging was completely converted back to a cubic spinel phase. Lattice parameter changes of each phase were calculated and showed a characteristic strain release during phase changes. After 15 full cycles the transition between these phases was no longer complete and the formation of the tetragonal spinel phase was no longer detected. A discussion of how these cycle-induced changes to phase transition behavior relate to capacity fade and overall cell performance is presented.

  17. Synthesis and electrochemical performance of nano-metastructured LiFePO4/C cathode material.

    PubMed

    Zhi, Xiaoke; Liang, Guangchuan; Wang, Li; Cui, Junyan; Yang, Limei

    2010-11-01

    The nano-metastructured LiFePO4/C composites were synthesized by carbothermal reduction method using starch gel as carbon source and dispersing media to obtain high tap density LiFePO4 with excellent electrochemical performance. The raw materials were coated by starch gel as compact precursors, which was sintered at 750 degrees C for 8 h to obtain high-density LiFePO4/C composite aggregated with nano-sized particles. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations showed that the primary particles had an average size of about 50-80 nm and the aggregates had a homogeneous particle size distribution of about 400 nm. The asprepared samples had a shortened lithium-ion diffusion length but with higher tap density, thus leading to the excellent electrochemical performance of the cathode materials. Electrochemical results showed that the samples delivered high discharge capacities of 155.6 and 120.7 mAh/g at 0.2C and 5C rates, respectively, with excellent cycling performance.

  18. Poly(3-methylthiophene) - A stable cathode-active material for secondary batteries

    NASA Astrophysics Data System (ADS)

    Nagatomo, Takao; Omoto, Osamu

    1988-09-01

    The electrical properties of poly(3-methylthiophene) (P3MT) films synthesized by electrochemical polymerization and the discharge characteristics of secondary batteries utilizing P3MT film as the cathode-active material are described. The P3MT was synthesized in film forms by electrochemical polymerization in the propylene carbonate solutions containing LiBF4 or LiAsF6. The conductivity of the AsF6(-) doped, 30 mole percent (m/o) P3MT film prepared at 25 C was about 200 S/cm. A P3MT/LiBF4 + PC + EC/Al (PC:propylene carbonate, EC:ethylene carbonate) battery was charged and discharged over 1200 cycles at the doping level of 9 percent while the coulombic efficiency maintained over 97 percent. The discharge characteristics are described in relation to the surface morphology of the films. This battery exhibited an energy density of 326 Wh/kg based on the weight of the electrode active material at a doping level of 35 percent. The self-discharge of this battery was relatively small.

  19. Surface reconstruction and chemical evolution of stoichiometric layered cathode materials for lithium-ion batteries.

    PubMed

    Lin, Feng; Markus, Isaac M; Nordlund, Dennis; Weng, Tsu-Chien; Asta, Mark D; Xin, Huolin L; Doeff, Marca M

    2014-03-27

    The present study sheds light on the long-standing challenges associated with high-voltage operation of LiNi(x)Mn(x)Co(1-2x)O2 cathode materials for lithium-ion batteries. Using correlated ensemble-averaged high-throughput X-ray absorption spectroscopy and spatially resolved electron microscopy and spectroscopy, here we report structural reconstruction (formation of a surface reduced layer, to transition) and chemical evolution (formation of a surface reaction layer) at the surface of LiNi(x)Mn(x)Co(1-2x)O2 particles. These are primarily responsible for the prevailing capacity fading and impedance buildup under high-voltage cycling conditions, as well as the first-cycle coulombic inefficiency. It was found that the surface reconstruction exhibits a strong anisotropic characteristic, which predominantly occurs along lithium diffusion channels. Furthermore, the surface reaction layer is composed of lithium fluoride embedded in a complex organic matrix. This work sets a refined example for the study of surface reconstruction and chemical evolution in battery materials using combined diagnostic tools at complementary length scales.

  20. Electrochemical Effects of Atomic Layer Deposition on Cathode Materials for Lithium Batteries

    NASA Astrophysics Data System (ADS)

    Scott, Isaac David

    One of the greatest challenges of modern society is to stabilize a consistent energy supply that will meet our growing energy demand while decreasing the use of fossil fuels and the harmful green house gases which they produce. Developing reliable and safe solutions has driven research into exploring alternative energy sources for transportation including fuel cells, hydrogen storage, and lithium-ion batteries (LIBs). For the foreseeable future, though, rechargeable batteries appear to be the most practically viable power source. To deploy LIBs in next-generation vehicles, it is essential to develop electrodes with durability, high energy density, and high power. Unfortunately, the power capability of LIBs is generally hindered by Li+-ion diffusion in micrometer-sized materials and the formation of an insulating solid electrolyte interface (SEI) layer on the surface of the active material. In addition, degradation of the battery material due to chemical and electrochemical reactions with the electrolyte lead to both capacity fade and safety concerns both at room and higher temperatures. The current study focuses on mitigating these issues for high voltage cathode materials by both using nanoscale particles to improve Li+-ion diffusion and using ultrathin nanoscale coatings to protect the battery materials from undesirable side reactions. The electrode material is coated with Al2O3 using atomic layer deposition (ALD), which is a method to grow conformal thin films with atomic thickness (angstrom level control) using sequential, self-limiting surface reactions. First, nano-LiCoO 2 is employed to demonstrate the effectiveness of ALD coatings and demonstrates a profound increase in rate performance (>250% improvement) over generally employed micrometer-sized particles. Second, the cathode materials LiNi 0.8Co0.15Al0.05O2, LiNi0.33Mn 0.33Co0.33O2, LiMn2O4, and LiNi0.5Mn1.5O4 were used to demonstrate the benefits ALD coatings have on thermal runaway. The results show a

  1. High sulfur-containing carbon polysulfide polymer as a novel cathode material for lithium-sulfur battery.

    PubMed

    Zhang, Yiyong; Peng, Yueying; Wang, Yunhui; Li, Jiyang; Li, He; Zeng, Jing; Wang, Jing; Hwang, Bing Joe; Zhao, Jinbao

    2017-09-12

    The lithium-sulfur battery, which offers a high energy density and is environmental friendly, is a promising next generation of rechargeable energy storage system. However, despite these attractive attributes, the commercialization of lithium-sulfur battery is primarily hindered by the parasitic reactions between the Li metal anode and dissolved polysulfide species from the cathode during the cycling process. Herein, we synthesize the sulfur-rich carbon polysulfide polymer and demonstrate that it is a promising cathode material for high performance lithium-sulfur battery. The electrochemical studies reveal that the carbon polysulfide polymer exhibits superb reversibility and cycle stability. This is due to that the well-designed structure of the carbon polysulfide polymer has several advantages, especially, the strong chemical interaction between sulfur and the carbon framework (C-S bonds) inhibits the shuttle effect and the π electrons of the carbon polysulfide compound enhance the transfer of electrons and Li(+). Furthermore, as-prepared carbon polysulfide polymer-graphene hybrid cathode achieves outstanding cycle stability and relatively high capacity. This work highlights the potential promise of the carbon polysulfide polymer as the cathode material for high performance lithium-sulfur battery.

  2. Two-Dimensional Titanium Carbide MXene As a Cathode Material for Hybrid Magnesium/Lithium-Ion Batteries.

    PubMed

    Byeon, Ayeong; Zhao, Meng-Qiang; Ren, Chang E; Halim, Joseph; Kota, Sankalp; Urbankowski, Patrick; Anasori, Babak; Barsoum, Michel W; Gogotsi, Yury

    2017-02-08

    As an alternative to pure lithium-ion, Li(+), systems, a hybrid magnesium, Mg(2+), and Li(+) battery can potentially combine the high capacity, high voltage, and fast Li(+) intercalation of Li-ion battery cathodes and the high capacity, low cost, and dendrite-free Mg metal anodes. Herein, we report on the use of two-dimensional titanium carbide, Ti3C2Tx (MXene), as a cathode in hybrid Mg(2+)/Li(+) batteries, coupled with a Mg metal anode. Free-standing and flexible Ti3C2Tx/carbon nanotube composite "paper" delivered ∼100 mAh g(-1) at 0.1 C and ∼50 mAh g(-1) at 10 C. At 1 C the capacity was maintained for >500 cycles at 80 mAh g(-1). The Mo2CTx MXene also demonstrated good performance as a cathode material in this hybrid battery. Considering the variety of available MXenes, this work opens the door for exploring a new large family of 2D materials with high electrical conductivity and large intercalation capacity as cathodes for hybrid Mg(2+)/Li(+) batteries.

  3. Electronic and Electrochemical Properties of Li 1–x Mn 1.5 Ni 0.5 O 4 Spinel Cathodes As a Function of Lithium Content and Cation Ordering

    DOE PAGES

    Moorhead-Rosenberg, Zach; Huq, Ashfia; Goodenough, John B.; ...

    2015-10-05

    The electronic and electrochemical properties of the high-voltage spinel LiMn1.5Ni0.5O4 as a function of cation ordering and lithium content have been investigated. Conductivity and activation energy measurements confirm that charge transfer occurs by small polaron hopping and the charge carrier conduction is easier in the Ni:3d band than in the in Mn:3d band. Seebeck coefficient data reveal that the Ni2+/3+. and Ni3+/4+ redox couples are combined in a single,3d band, and that maximum charge carrier concentration occurs where the average Ni oxidation state is close to 3+, corresponding to x = 0.5 in Li Li1-xMn1.5Ni0.5O4. Furthermore, maximum electronic conductivity ismore » found at x = 0.5, regardless of cation ordering. The thermodynamically stable phases formed during cycling were investigated by recording the X-ray diffraction (XRD) of chemically delithiated powders. The more ordered spinels maintained two separate two-phase regions upon lithium extraction, while the more disordered samples exhibited a solid-solubility region from LiMn1.5Ni0.5O4 to Li0.5Mn1.5Ni0.5O4. The conductivity and phase-transformation data of four samples with varying degrees of cation ordering were compared to the electrochemical data collected with lithium cells. Only the most ordered spinel showed inferior rate performance, while the sample annealed for a shorter time performed comparable to the unannealed or disordered samples. Our results challenge the most common beliefs about high-voltage spinel: (i) low Mn3+ content is responsible for poor rate performance and (ii) thermodynamically stable solid-solubility is critical for fast kinetics.« less

  4. The Energetics of Oxide Multilayer Systems: SOFC Cathode and Electrolyte Materials

    NASA Astrophysics Data System (ADS)

    Kemik, Nihan

    Complex oxides are evoking a surge of scientific and technological interest due to the unexpected properties of their interfaces which have been shown to differ from the constituent materials. Layered oxide structures have found wide use in applications ranging from electronic and magnetic devices to solid oxide fuel cells (SOFCs). For devices such as SOFCs which utilize multilayers at elevated temperatures, it is critical to know the relative stabilities of these interfaces since they directly influence the device performance. In this work, we explored the energetics of two oxide multilayer systems which are relevant for SOFCs components using high temperature solution calorimetry and differential scanning calorimetry (DSC). The fundamental understanding of the interfacial and structural properties of multilayers combined with the information about phase stabilities is essential in materials selection for components for intermediate temperature SOFC's. For cathode materials, we investigated the family of perovskite oxides, La0.7Sr0.3MO3, where M=Mn and Fe, as well as their solid solution phase. Manganites have been the most investigated cathode material, while the ferrites are also being considered for future use due to their thermodynamic stability and close thermal expansion coefficient with the commonly used electrolyte materials. For the bulk La0.7Sr0.3FexMn1-xO 3 solid solution, high temperature oxide melt drop solution calorimetry was performed to determine the enthalpies of formation from binary oxides and the enthalpy of mixing. It was shown that the symmetry of the perovskite structure, the valence of transition metal, and the energetics are highly interdependent and the balance between the different valence states of the Mn and Fe ions is the main factor in determining the energetics. The energetics of interfaces in multilayered structures was investigated by high temperature oxide melt solution calorimetry for the first time. The drop solution

  5. Facile synthesis and characterization of a SnO2-modified LiNi0.5Mn1.5O4 high-voltage cathode material with superior electrochemical performance for lithium ion batteries.

    PubMed

    Ma, Feng; Geng, Fushan; Yuan, Anbao; Xu, Jiaqiang

    2017-04-12

    A thin-layer-SnO2 modified LiNi0.5Mn1.5O4@SnO2 material is synthesized via a facile synthetic approach. It is physically and electrochemically characterized as a high-voltage lithium ion battery cathode and compared to the pristine LiNi0.5Mn1.5O4 material prepared under similar conditions. The two materials are proved to be crystals of a well-defined disordered spinel phase with the morphology of aggregates of micron/submicron polyhedral particles. The Mn(3+) ions and the inactive NixLiyO phase in the LiNi0.5Mn1.5O4@SnO2 is less than those in the LiNi0.5Mn1.5O4 due to incorporation of a very small amount of Sn(2+) into the spinel structure upon high-temperature calcination of the precursor. Besides, the mean particle size of the LiNi0.5Mn1.5O4@SnO2 is obviously smaller than that of the LiNi0.5Mn1.5O4. The LiNi0.5Mn1.5O4@SnO2 demonstrates much superior electrochemical performance over the LiNi0.5Mn1.5O4 in terms of specific capacity, rate capability and cyclability. For example, the discharge capacities at current rates of 0.2C, 2C and 20C are 145.4, 139.9 and 112.2 mA h g(-1), respectively. A capacity retention rate of ca. 75% is obtained after 500 cycles at 2C rate. The improved electrochemical performance is attributed to the positive effect of the surface protective SnO2 coating layer as well as the structural and morphological modifications of the spinel.

  6. Lightweight Cathodes For Nickel Batteries

    NASA Technical Reports Server (NTRS)

    Britton, Doris L.

    1996-01-01

    Lightweight cathodes for rechargeable nickel-based electrochemical cells undergoing development. In cathodes, mats of nickel fibers are substrates providing structural support of, and electrical contact with, active cathode material. Offers specific energies greater than sintered nickel plaque cathodes. Electrodes used in rechargeable batteries for applications in which weight major concern, including laptop computers, cellular phones, flashlights, soldiers' backpacks, and electric vehicles.

  7. Nanosized LiFePO4 cathode materials for lithium ion batteries.

    PubMed

    Gu, Hal-Bon; Jun, Dae-Kyoo; Park, Gye-Choon; Jin, Bo; Jin, En Mei

    2007-11-01

    In this study, we prepared nano-particles of LiFePO4 as cathode material for lithium ion batteries by the solid-state reaction. A simple one-step heat treatment has been employed with control of heating temperature and heated LiFePO4 at 650 degrees C exhibited higher 125 mA h/g of the discharge capacity than 600 degrees C, 700 degrees C. To improve conductivity of the inter-particle, carbon coating was carried out by raw carbon or pyrene as carbon sources and their morphological properties of particles on the carbon coating was compared with by FE-SEM, TEM. From the FE-SEM results, the particles of carbon added LiFePO4 have much smaller size than LiFePO4 as below 300 nm. When adding pyrene (10 wt%), the carbon surrounded non-uniformly with surface of the particles compared with adding raw carbon which wrapped uniformly with carbon web and it was exhibited 152 mA h/g of the discharge capacity on LiFePO4/C composite cells at 10th cycle.

  8. Defect physics vis-à-vis electrochemical performance in layered mixed-metal oxide cathode materials

    NASA Astrophysics Data System (ADS)

    Hoang, Khang; Johannes, Michelle

    Layered mixed-metal oxides with different compositions of (Ni,Co,Mn) [NCM] or (Ni,Co,Al) [NCA] have been used in commercial lithium-ion batteries. Yet their defect physics and chemistry is still not well understood, despite having important implications for the electrochemical performance. In this presentation, we report a hybrid density functional study of intrinsic point defects in the compositions LiNi1/3Co1/3Mn1/3O2 (NCM1/3) and LiNi1/3Co1/3Al1/3O2 (NCA1/3) which can also be regarded as model compounds for NCM and NCA. We will discuss defect landscapes in NCM1/3 and NCA1/3 under relevant synthesis conditions with a focus on the formation of metal antisite defects and its implications on the electrochemical properties and ultimately the design of NCM and NCA cathode materials.

  9. Nondestructive Thickness Quantification for Nanoscale Coatings on Li-Ion Battery Cathode Material.

    PubMed

    Ouyang, Wuye; Todd, Clifford S

    2017-03-07

    Nickel manganese cobalt oxide (NMC) is a high energy capacity cathode material that attracts the interest of many research groups. Coating a protection layer on the NMC surface is one approach to improve its cycling and safety performance. However, there is no standard and consistent way to characterize the coating performance (thickness) of this protection layer, especially due to the nanoscale of primary particle and spherical morphology of the secondary particle. In this paper, a novel empirical method based on energy dispersive X-ray spectroscopy (EDX) analysis at low accelerating voltage is proposed to evaluate the protection layer thickness on the scale of tens of nanometers. The layer thickness is characterized by measuring the intensity decrease of a substrate element due to absorption by overlying coating layers. An internal standard coating (metal layer) is applied to mimic the morphology influence and improve the accuracy of thickness quantitation. For the model sample evaluation, carbon layer coatings of 1 to 10 nm thickness were successfully quantified by this method.

  10. Li2S-reduced graphene oxide nanocomposites as cathode material for lithium sulfur batteries

    NASA Astrophysics Data System (ADS)

    Han, Kai; Shen, Jingmei; Hayner, Cary M.; Ye, Hongqi; Kung, Mayfair C.; Kung, Harold H.

    2014-04-01

    A lithium sulfide-reduced graphene oxide nanocomposite (Li2S-rGO) was synthesized and evaluated as the cathode material and Li source for the assembly of Li-S batteries. The composite, with a unique 3-D pocket structure, was synthesized by a combination of facile solution chemistry and thermal treatment. The as-prepared Li2S-rGO nanocomposites were characterized by X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy, which showed 20-40 nm Li2S particles homogeneously dispersed between reduced graphene oxide sheets. Li2S contents as high as ∼66% could be obtained. When used with an electrolyte containing LiNO3 and polysulfide, the Li2S-rGO nanocomposites exhibited a high initial capacity of 982 mAh g-1 Li2S. However, there was noticeable capacity fade in subsequent cycles, probably due to polysulfide dissolution and the shuttle mechanism, but a capacity of 315 mAh g-1 could still be obtained after 100 cycles, with 90-95% coulomb efficiency. The effect of polysulfide additive in the electrolyte on the activation of Li2S in the first delithiation step was discussed.

  11. Li 3V 2(PO 4) 3 cathode material synthesized by chemical reduction and lithiation method

    NASA Astrophysics Data System (ADS)

    Zheng, Jun-Chao; Li, Xin-Hai; Wang, Zhi-Xing; Guo, Hua-Jun; Hu, Qi-Yang; Peng, Wen-Jie

    The monoclinic-type Li 3V 2(PO 4) 3 cathode material was synthesized via calcining amorphous Li 3V 2(PO 4) 3 obtained by chemical reduction and lithiation of V 2O 5 using oxalic acid as reducer and lithium carbonate as lithium source in alcohol solution. The amorphous Li 3V 2(PO 4) 3 precursor was characterized by using TG-DSC and XPS. The results showed that the V 5+ was reduced to V 3+ by oxalic acid at ambient temperature and pressure. The prepared Li 3V 2(PO 4) 3 was characterized by XRD and SEM. The results indicated the Li 3V 2(PO 4) 3 powder had good crystallinity and mesoporous morphology with an average diameter of about 30 nm. The pure Li 3V 2(PO 4) 3 exhibits a stable discharge capacity of 130.08 mAh g -1 at 0.1 C (14 mA g -1).

  12. Redox potential trend with transition metal elements in lithium-ion battery cathode materials

    NASA Astrophysics Data System (ADS)

    Chen, Zhenlian; Li, Jun

    2013-03-01

    First-principles calculations are performed to investigate the relationship between the intrinsic voltage and element-lattice for the popular transition metal oxides and polyoxyanionic compounds as cathode materials for lithium-ion batteries. A V-shape redox potential in olivine phosphates LiMPO4 and orthogonal silicates Li2MSiO4 (M =Mn, Fe, Co, Ni), and an N-shape one in layered oxides LiMO2 (M =Mn, Fe, Co, Ni, Cu) relative to transition metal M elements are found to be inversely characteristic of electronic energy contribution, which costs energy in the lithiation process and is defined as electron affinity. The maxima of electron affinity, locating at different elements for different types of crystal lattices are determined by delectronic configurations that cross the turning point of a full occupancy of electronic bands, which is determined by the cooperative effect of crystal field splitting and intraionic exchange interactions. The Ningbo Key Innovation Team, National Natural Science Foundation of China, Postdoctoral Foundation of China

  13. Thermodynamic Properties of Polymorphs of Fluorosulfate Based Cathode Materials with Exchangeable Potassium Ions.

    PubMed

    Shivaramaiah, Radha; Lander, Laura; Nagabhushana, G P; Rousse, Gwenaëlle; Tarascon, Jean-Marie; Navrotsky, Alexandra

    2016-11-04

    FeSO4 F-based frameworks have recently emerged as attractive candidates for alkali insertion electrodes. Mainly owing to their rich crystal chemistry, they offer a variety of new host structures with different electrochemical performances and physical properties. In this paper we report the thermodynamic stability of two such K-based "FeSO4 F" host structures based on direct solution calorimetric measurements. KFeSO4 F has been reported to crystallize in two different polymorphic modifications-monoclinic and orthorhombic. The obtained enthalpies of formation from binary components (KF plus FeSO4 ) are negative for both polymorphs, indicating that they are thermodynamically stable at room temperature, which is very promising for the future exploration of sulfate based cathode materials. Our measurements show that the low-temperature monoclinic polymorph is enthalpically more stable than the orthorhombic phase by ≈10 kJ mol(-1) , which is consistent with the preferential formation of monoclinic KFeSO4 F at low temperature. Furthermore, observed phase transformations and difficulties in the synthesis process can be explained based on the obtained calorimetric results. The KMnSO4 F orthorhombic phase is more stable than both polymorphs of KFeSO4 F.

  14. Surface modified CFx cathode material for ultrafast discharge and high energy density

    DOE PAGES

    Dai, Yang; Zhu, Yimei; Cai, Sendan; ...

    2014-11-10

    Li/CFx primary possesses the highest energy density of 2180 W h kg⁻¹ among all primary lithium batteries. However, a key limitation for the utility of this type of battery is in its poor rate capability because the cathode material, CFx, is an intrinsically poor electronic conductor. Here, we report on our development of a controlled process of surface de-fluorination under mild hydrothermal conditions to modify the highly fluorinated CFx. The modified CFx, consisting of an in situ generated shell component of F-graphene layers, possesses good electronic conductivity and removes the transporting barrier for lithium ions, yielding a high-capacity performance andmore » an excellent rate-capability. Indeed, a capacity of 500 mA h g⁻¹ and a maximum power density of 44 800 W kg⁻¹ can be realized at the ultrafast rate of 30 C (24 A g⁻¹), which is over one order of magnitude higher than that of the state-of-the-art primary lithium-ion batteries.« less

  15. Surface modified CFx cathode material for ultrafast discharge and high energy density

    SciTech Connect

    Dai, Yang; Zhu, Yimei; Cai, Sendan; Wu, Lijun; Yang, Weijing; Xie, Jingying; Wen, Wen; Zheng, Jin-Cheng; Zheng, Yi

    2014-11-10

    Li/CFx primary possesses the highest energy density of 2180 W h kg⁻¹ among all primary lithium batteries. However, a key limitation for the utility of this type of battery is in its poor rate capability because the cathode material, CFx, is an intrinsically poor electronic conductor. Here, we report on our development of a controlled process of surface de-fluorination under mild hydrothermal conditions to modify the highly fluorinated CFx. The modified CFx, consisting of an in situ generated shell component of F-graphene layers, possesses good electronic conductivity and removes the transporting barrier for lithium ions, yielding a high-capacity performance and an excellent rate-capability. Indeed, a capacity of 500 mA h g⁻¹ and a maximum power density of 44 800 W kg⁻¹ can be realized at the ultrafast rate of 30 C (24 A g⁻¹), which is over one order of magnitude higher than that of the state-of-the-art primary lithium-ion batteries.

  16. Kinetic behavior of LiFeMgPO 4 cathode material for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Hong, Jian; Wang, Chunsheng; Kasavajjula, Uday

    LiFe 0.9Mg 0.1PO 4 material was prepared by mechanical milling method, followed by heat treatment. The equilibrium potential-composition isotherm of LiFe 0.9Mg 0.1PO 4 and charge-discharge kinetics of LiFe 0.9Mg 0.1PO 4 were measured using galvanostatic intermittent titration technique (GITT), potential-step chronoamperometry (PSCA), and electrochemical impedance spectroscopy (EIS). The rate performance of the cathode is controlled by the charge-transfer kinetics, electronic conductivity, Li-ion diffusion capability, and phase transformation rate. Since LiFe 0.9Mg 0.1PO 4 has a fast charge-transfer reaction and high electronic and ionic diffusivity, the phase transformation between LiFe 0.9Mg 0.1PO 4 and Li 0.1Fe 0.9Mg 0.1PO 4 begins to play a more important role in the charge-discharge process, as is evident by an inductive loop induced by the phase transformation in the low frequency region of EIS. The phase purity and morphology of LiFe 0.9Mg 0.1PO 4 were also observed using X-ray diffraction (XRD) and scanning electron microscopy (SEM).

  17. Carbon fiber reinforced mortar as an electrical contact material for cathodic protection

    SciTech Connect

    Fu, X.; Chung, D.D.L.

    1995-05-01

    For a joint between old plain mortar and new mortar (which serves as an electrical contact material for cathodic protection of steel-reinforced old mortar), short carbon fiber addition to the new mortar was found to decrease both the contact resistivity and the new mortar`s volume resistivity. Whether the new mortar contained fibers or not, the contact resistance was higher than the new mortar`s volume resistance perpendicular to the contact and was lower than the new mortar`s volume resistance parallel to the contact. In the presence of latex, the volume resistivity was 3.1 {times} 10{sup 5}, 1.4 {times} 10{sup 3} and 1.2 {times} 10{sup 2} {Omega}{center_dot}cm and the contact resistivity was 5.9 {times} 10{sup 6}, 2.7 {times} 10{sup 5} and 2.6 {times} 10{sup 4} {Omega}{center_dot}cm{sup 2} at fiber contents of 0, 0.53 and 1.1 vol.% respectively. Latex addition alone to the new mortar increased slightly both contact resistivity and new mortar`s volume resistivity. All resistivities increased very slightly with curing age.

  18. Binary and ternary nano-catalysts as cathode materials in proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Trimm, Bryan Dunning

    The need for alternative energy, in order to reduce dependence on petroleum based fuels, has increased in recent years. Public demand is at an all-time high for low emitting or none polluting energy sources, driving the research for cleaner technology. Lithium batteries and fuel cells have the ability to produce this alternative energy with much cleaner standards, while allowing for portability and high energy densities. This work focuses on the performance of nanocatalysts in Proton Exchange Membrane Fuel Cell or PEMFC. A key technical challenge is the sluggish rate for oxygen reduction reaction at the cathode of PEMFC, which requires highly-active and stable catalysts. Our investigation is directed at increasing stability and durability as well as reducing high loading of noble metals in these catalyst materials. Binary and ternary structured nanomaterials, e.g., Pt51V1Co48/C and Pd xCu1-x/C, have been synthesized and tested in a PEMFC, in order to gain a better understanding of their durability and efficiency. In addition to electrochemical characterization, synchrotron x-ray techniques at the Advance Photon Source in Argonne National Lab have also been used for the structural characterization.

  19. Electrochemical studies on niobium triselenide cathode material for lithium rechargeable cells

    SciTech Connect

    Ratnakumar, B.V.; Ni, C.L.; DiStefano, S.; Nagasubramanian, G.; Bankston, C.P.

    1989-01-01

    Niobium triselenide offers promise as a high energy density cathode material for ambient temperature lithium rechargeable cells. The electrochemical behavior of NbSe/sub 3/ in the battery electrolyte, i.e., 1.5m LiAsF/sub 6//2 Me-THF is reported here. A detailed study has been carried out using various ac and dc electrochemical techniques to establish the mechanism of intercalation of three equivalents of Li with NbSe/sub 3/ as well as the rate governing processes in the reduction of NbSe/sub 3/. Based on the experimental data, an equivalent circuit has been formulated to represent the NbSe/sub 3/-solution interface. The kinetic parameters for the reduction of NbSe/sub 3/ were evaluated from the ac and dc measurements. Finally, the structural change in NbSe/sub 3/ on lithiation during initial discharge which results in higher cell voltages and different electrochemical response as compared to virgin NbSe/sub 3/ was identified to be a loss of crystallographic order, i.e., amorphous by x-ray diffraction.

  20. Conformal ALON® and spinel windows

    NASA Astrophysics Data System (ADS)

    Goldman, Lee M.; Smith, Mark; Ramisetty, Mohan; Jha, Santosh; Sastri, Suri

    2017-05-01

    The requirements for modern aircraft based reconnaissance systems are driving the need for conformal windows for future sensor systems. However, limitations on optical systems and the ability to produce windows in complex geometries currently limit the geometry of existing windows and window assemblies to faceted assemblies of flat windows. ALON consists primarily of aluminum and oxygen, similar to that of alumina, with a small amount of nitrogen added to help stabilize the cubic gamma-AlON phase. ALON's chemical similarity to alumina, translates into a robust manufacturing process. This ease of processing has allowed Surmet to produce ALON windows and domes in a wide variety of geometries and sizes. Spinel (MgAl2O4) contains equal molar amounts of MgO and Al2O3, and is a cubic material, that transmits further into the Infrared than ALON. Spinel is produced via powder processing techniques similar to those used to produce ALON. Surmet is now applying the lessons learned with ALON to produce conformal spinel windows and domes as well.

  1. Vanadium-spinel composites for structural applications in hostile environments

    SciTech Connect

    Schwarz, R.B.; Wetteland, C.J.; Shen, T.D.

    1997-05-01

    Vanadium-spinel composites are promising materials for structural applications in radiation environments. Powders of two Vanadium-spinel composites, 20/80 vol. %, were prepared by (a) ball milling mixtures of vanadium and spinel powders (alloy VSLP) and (b) through a self-sustained reaction synthesis of vanadium, MgO, and Al powders (alloy VSHP). These powders were consolidated by hot isostatic pressing. Most of the V and spinel domains in the the compacts are sub-micron in size. The compacts have K{sub c} toughness values of 3.9, about three times the toughness obtained by hipping mixtures of commercial powders.

  2. Alternative perovskite materials as a cathode component for intermediate temperature single-chamber solid oxide fuel cell

    NASA Astrophysics Data System (ADS)

    Gaudillère, Cyril; Olivier, Louis; Vernoux, Philippe; Zhang, Chunming; Shao, Zongping; Farrusseng, David

    This paper exploits the suitability of three perovskite materials Ba 0.5Sr 0.5Co 0.8Fe 0.2O 3- δ (BSCF), GdBaCo 2O 5+ δ (GBC) and Ba 0.5Sr 0.5Mn 0.7Fe 0.3O 3- δ (BSMF) as SOFC cathodes in the single-chamber configuration operating at the intermediate temperature range. TG analysis showed high thermal stability depending on the crystalline phases of the materials. The catalytic activity of these three materials for hydrocarbon conversion was investigated under a realistic feed, i.e. with hydrocarbon, oxygen, water and carbon dioxide. Electrochemical impedance spectroscopy of the various cathodes tested in symmetric cell configuration revealed a B-site dependence of the electrode catalytic activity for oxygen reduction. High temperature (1000 °C) powder reactivity tests over a gadolinium doped-ceria (CGO) and perovskite cathode revealed excellent chemical compatibility of BSMF and CGO. Catalytic tests associated with thermal and structural characterization attest to the suitability of these materials in the single-chamber configuration.

  3. Mixed ion/electron-conductive protective soft nanomatter-based conformal surface modification of lithium-ion battery cathode materials

    NASA Astrophysics Data System (ADS)

    Park, Jang-Hoon; Kim, Ju-Myung; Lee, Chang Kee; Lee, Sang-Young

    2014-10-01

    Understanding and control of interfacial phenomena between electrode material and liquid electrolytes are of major scientific importance for boosting development of high-performance lithium ion batteries with reliable electrochemical/safety attributes. Here, as an innovative surface engineering approach to address the interfacial issues, a new concept of mixed ion/electron-conductive soft nanomatter-based conformal surface modification of the cathode material is presented. The soft nanomatter is comprised of an electron conductive carbonaceous (C) substance embedded in an ion conductive polyimide (PI) nanothin compliant film. In addition to its structural uniqueness, the newly proposed surface modification benefits from a simple fabrication process. The PI/carbon soft nanomatter is directly synthesized on LiCoO2 surface via one-pot thermal treatment of polyamic acid (=PI precursor) and sucrose (=carbon source) mixture, where the LiCoO2 powders are chosen as a model system to explore the feasibility of this surface engineering strategy. The resulting PI/carbon coating layer facilitates electronic conduction and also suppresses unwanted side reactions arising from the cathode material-liquid electrolyte interface. These synergistic coating effects of the multifunctional PI/carbon soft nanomatter significantly improve high-voltage cell performance and also mitigate interfacial exothermic reaction between cathode material and liquid electrolyte.

  4. Carbon black as an alternative cathode material for electrical energy recovery and transfer in a microbial battery.

    PubMed

    Zhang, Xueqin; Guo, Kun; Shen, Dongsheng; Feng, Huajun; Wang, Meizhen; Zhou, Yuyang; Jia, Yufeng; Liang, Yuxiang; Zhou, Mengjiao

    2017-08-01

    Rather than the conventional concept of viewing conductive carbon black (CB) to be chemically inert in microbial electrochemical cells (MECs), here we confirmed the redox activity of CB for its feasibility as an electron sink in the microbial battery (MB). Acting as the cathode of a MB, the solid-state CB electrode showed the highest electron capacity equivalent of 18.58 ± 0.46 C/g for the unsintered one and the lowest capacity of 2.29 ± 0.48 C/g for the one sintered under 100% N2 atmosphere. The capacity vibrations of CBs were strongly in coincidence with the abundances of C=O moiety caused by different pretreatments and it implied one plausible mechanism based on CB's surface functionality for its electron capturing. Once subjected to electron saturation, CB could be completely regenerated by different strategies in terms of electrochemical discharging or donating electrons to biologically-catalyzed nitrate reduction. Surface characterization also revealed that CB's regeneration fully depended on the reversible shift of C=O moiety, further confirming the functionality-based mechanism for CB's feasibility as the role of MB's cathode. Moreover, resilience tests demonstrated that CB cathode was robust for the multi-cycles charging-discharging operations. These results imply that CB is a promising alternative material for the solid-state cathode in MBs.

  5. Preparation and characterization of SnO2 and Carbon Co-coated LiFePO4 cathode materials.

    PubMed

    Wang, Haibin; Liu, Shuxin; Huang, Yongmao

    2014-04-01

    The SnO2 and carbon co-coated LiFePO4 cathode materials were successfully synthesized by solid state method. The microstructure and morphology of LiFePO4 composites were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and transmission electron microscope. The results showed that the SnO2 and carbon co-coated LiFePO4 cathode materials exhibited more uniform particle size distribution. Compared with the uncoated LiFePO4/C, the structure of LiFePO4 with SnO2 and carbon coating had no change. The existence of SnO2 and carbon coating layer effectively enhanced the initial discharge capacity. Among the investigated samples, the one with DBTDL:LiFePO4 molar ratios of 7:100 exhibited the best electrochemical performance.

  6. Synthesis and characterization of LiFePO4/C cathode materials by sol-gel method.

    PubMed

    Liu, Shuxin; Yin, Hengbo; Wang, Haibin; Wang, Hong

    2014-09-01

    The carbon coated LiFePO4 cathode materials (LiFePO4/C) were successfully synthesized by sol-gel method with glucose, citric acid and PEG-4000 as dispersant and carbon source, respectively. The microstructure and grain size of LiFePO4/C composite were characterized by X-ray diffraction, Raman spectroscopy, transmission electron microscopy. The results showed that the carbon source and calcination temperature had important effect on the graphitization degree of carbon; the carbon decomposed by citric acid had higher graphitization degree; with calcination temperature rising, the graphitization degree of carbon increased and the particles size increased. The graphitization degree and grain size were very important for improving the electrochemical performance of LiFePO4 cathode materials, according to the experimental results, the sample LFP-700 (LFP-C) which was synthesized with citric acid as dispersant at 700 degree C had lower polarization and larger discharge capacity.

  7. Optimization of a microbial fuel cell for wastewater treatment using recycled scrap metals as a cost-effective cathode material.

    PubMed

    Lefebvre, Olivier; Tan, Zi; Shen, Yujia; Ng, How Y

    2013-01-01

    Microbial fuel cell (MFC) for wastewater treatment is still hindered by the prohibitive cost of cathode material, especially when platinum is used to catalyze oxygen reduction. In this study, recycled scrap metals could be used efficiently as cathode material in a specially-designed MFC. In terms of raw power, the scrap metals ranked as follows: W/Co > Cu/Ni > Inconel 718 > carpenter alloy; however, in terms of cost and long term stability, Inconel 718 was the preferred choice. Treatment performance--assessed on real and synthetic wastewater--was considerably improved either by filling the anode compartment with carbon granules or by operating the MFC in full-loop mode. The latter option allowed reaching 99.7% acetate removal while generating a maximum power of 36 W m(-3) at an acetate concentration of 2535 mg L(-1). Under these conditions, the energy produced by the system averaged 0.1 kWh m(-3) of wastewater treated.

  8. Yolk-shelled cathode materials with extremely high electrochemical performances prepared by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Choi, Seung Ho; Hong, Young Jun; Kang, Yun Chan

    2013-08-01

    A facile, continuous preparation process of yolk-shell-structured lithium-metal oxide powders without a template for use as cathode materials in lithium ion batteries is introduced for the first time. Single and double-shelled LiNi0.5Mn1.5O4 yolk-shell powders as the first target materials are prepared directly by spray pyrolysis from a spray solution with sucrose, at a short residence time of 4 s. Fast combustion and contraction of a carbon-mixed oxide composite intermediate, formed from a micro-sized droplet inside a hot wall reactor maintained at 700 °C, produces the yolk-shell powders. The yolk-shell structure of the precursor powders directly prepared by spray pyrolysis is well maintained even at a high post-treatment temperature of 750 °C. The yolk-shell LiNi0.5Mn1.5O4 powders delivered a 1000th high discharge capacity of 108 mA h g-1 at 10 C. The discharge capacities are as high as 103, 95, and 91 mA h g-1 at extremely high discharge rates of 100, 200, and 300 C and the corresponding specific energy densities are 420, 370, and 328 W h kg-1. The capacity retention at a constant discharge rate of 200 C is 90% after 500 cycles.A facile, continuous preparation process of yolk-shell-structured lithium-metal oxide powders without a template for use as cathode materials in lithium ion batteries is introduced for the first time. Single and double-shelled LiNi0.5Mn1.5O4 yolk-shell powders as the first target materials are prepared directly by spray pyrolysis from a spray solution with sucrose, at a short residence time of 4 s. Fast combustion and contraction of a carbon-mixed oxide composite intermediate, formed from a micro-sized droplet inside a hot wall reactor maintained at 700 °C, produces the yolk-shell powders. The yolk-shell structure of the precursor powders directly prepared by spray pyrolysis is well maintained even at a high post-treatment temperature of 750 °C. The yolk-shell LiNi0.5Mn1.5O4 powders delivered a 1000th high discharge capacity of 108 m

  9. Functionally Graded Cathodes for Solid Oxide Fuel Cells

    SciTech Connect

    Harry Abernathy; Meilin Liu

    2006-12-31

    One primary suspected cause of long-term performance degradation of solid oxide fuels (SOFCs) is the accumulation of chromium (Cr) species at or near the cathode/electrolyte interface due to reactive Cr molecules originating from Cr-containing components (such as the interconnect) in fuel cell stacks. To date, considerable efforts have been devoted to the characterization of cathodes exposed to Cr sources; however, little progress has been made because a detailed understanding of the chemistry and electrochemistry relevant to the Cr-poisoning processes is still lacking. This project applied multiple characterization methods - including various Raman spectroscopic techniques and various electrochemical performance measurement techniques - to elucidate and quantify the effect of Cr-related electrochemical degradation at the cathode/electrolyte interface. Using Raman microspectroscopy the identity and location of Cr contaminants (SrCrO{sub 4}, (Mn/Cr){sub 3}O{sub 4} spinel) have been observed in situ on an LSM cathode. These Cr contaminants were shown to form chemically (in the absence of current flowing through the cell) at temperatures as low as 625 C. While SrCrO{sub 4} and (Mn/Cr){sub 3}O{sub 4} spinel must preferentially form on LSM, since the LSM supplies the Sr and Mn cations necessary for these compounds, LSM was also shown to be an active site for the deposition of Ag{sub 2}CrO{sub 4} for samples that also contained silver. In contrast, Pt and YSZ do not appear to be active for formation of Cr-containing phases. The work presented here supports the theory that Cr contamination is predominantly chemically-driven and that in order to minimize the effect, cathode materials should be chosen that are free of cations/elements that could preferentially react with chromium, including silver, strontium, and manganese.

  10. Nanoscale spinel LiFeTiO4 for intercalation pseudocapacitive Li(+) storage.

    PubMed

    Chen, Ruiyong; Knapp, Michael; Yavuz, Murat; Ren, Shuhua; Witte, Ralf; Heinzmann, Ralf; Hahn, Horst; Ehrenberg, Helmut; Indris, Sylvio

    2015-01-14

    Intercalation pseudocapacitive Li(+) storage has been recognized recently in metal oxide materials, wherein Li(+) intercalation into the lattice is not solid-state diffusion-limited. This may bridge the performance gap between electrochemical capacitors and battery materials. To date, only a few materials with desired crystal structure and with well-defined nanoarchitectures have been found to exhibit such attractive behaviour. Herein, we report for the first time that nanoscale spinel LiFeTiO4 as a cathode material for Li-ion batteries exhibits intercalation pseudocapacitive Li(+) storage behaviour. Nanoscale LiFeTiO4 nanoparticles with native carbon coating were synthesized by a sol-gel route. A fast and large-amount of Li(+) storage (up to 1.6 Li(+) per formula unit over cycling) in the nanoscale LiFeTiO4 host has been achieved without compromising kinetics.

  11. Defect Physics, Delithiation Mechanism, and Electronic and Ionic Conduction in Layered Lithium Manganese Oxide Cathode Materials

    NASA Astrophysics Data System (ADS)

    Hoang, Khang

    2015-02-01

    Layered Li Mn O2 and Li2Mn O3 are of great interest for lithium-ion battery cathodes because of their high theoretical capacities. The practical application of these materials is, however, limited due to poor electrochemical performance. We herein report a comprehensive first-principles study of defect physics in Li Mn O2 and Li2Mn O3 using hybrid density-functional calculations. We find that manganese antisites have low formation energies in Li Mn O2 and may act as nucleation sites for the formation of impurity phases. The antisites can also occur with high concentrations in Li2Mn O3 ; however, unlike in Li Mn O2 , they can be eliminated by tuning the experimental conditions during preparation. Other intrinsic point defects may also occur and have an impact on the materials' properties and functioning. An analysis of the formation of lithium vacancies indicates that lithium extraction from Li Mn O2 is associated with oxidation at the manganese site, resulting in the formation of manganese small hole polarons; whereas in Li2Mn O3 the intrinsic delithiation mechanism involves oxidation at the oxygen site, leading to the formation of bound oxygen hole polarons ηO+ . The layered oxides are found to have no or negligible bandlike carriers, and they cannot be doped n or p type. The electronic conduction proceeds through hopping of hole and/or electron polarons; the ionic conduction occurs through lithium monovacancy and/or divacancy migration mechanisms. Since ηO+ is not stable in the absence of negatively charged lithium vacancies in bulk Li2Mn O3 , the electronic conduction near the start of delithiation is likely to be poor. We suggest that the electronic conduction associated with ηO+ and, hence, the electrochemical performance of Li2Mn O3 can be improved through nanostructuring and/or ion substitution.

  12. Hard X-ray Fluorescence Measurements of Heteroepitaxial Solid Oxide Fuel Cell Cathode Materials

    SciTech Connect

    Davis, Jacob N.; Miara, Lincoln J.; Saraf, Laxmikant V.; Kaspar, Tiffany C.; Gopalan, Srikanth; Pal, Uday B.; Woicik, Joseph C.; Basu, Soumendra N.; Ludwig, Karl F.

    2012-12-01

    Commonly, SOFCs are operated at high temperatures (above 800°C). At these temperatures expensive housing is needed to contain an operating stack as well as coatings to contain the oxidation of the metallic interconnects. Lowering the temperature of an operating device would allow for more conventional materials to be used, thus lowering overall cost. Understanding the surface chemical states of cations in the surface of the SOFC cathode is vital to designing a system that will perform well at lower temperatures. The samples studied were grown by pulsed laser deposition (PLD) at the Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory (PNNL). 20% strontium doped lanthanum manganite (LSM-20) was grown on YSZ and NGO (neodymium gallate). The films on YSZ have a fiber texture. LSM-20 on NGO is heteroepitaxial. Lanthanum strontium cobalt ferrite (LSCF-6428) films were grown on LAO and YSZ with a GDC barrier layer. Total X-ray Reflection Fluorescence (TXRF) was used to depth profile the samples. In a typical experiment, the angle of the incident beam is varied though the critical angle. Below the critical angle, the x-ray decays as an evanescent wave and will only penetrate the top few nanometers. TXRF experiments done on LSM films have suggested strontium segregates to the surface and form strontium enriched nanoparticles (1). It should be pointed out that past studies have focused on 30% strontium A-site doping, but this project uses 20% strontium doped lanthanum manganite. XANES and EXAFS data were taken as a function of incoming angle to probe composition as a function of depth. XANES spectra can be difficult to analyze fully. For other materials density functional theory calculations compared to near edge measurements have been a good way to understand the 3d valence electrons (2).

  13. Evaluation of several electrolyte mixture-cathode material combinations in electrodeposition of americium radioisotopes for alpha-spectrometric measurements.

    PubMed

    Krmpotić, Matea; Rožmarić, Martina; Benedik, Ljudmila

    2017-10-01

    Three different types of electrolytes, subsequently modified and adjusted, in combination with three cathode materials used as source backings were analysed for electrodeposition of americium isotopes for alpha-spectrometric measurements. The obtained results are discussed in terms of electrodeposition yield and source quality (source homogeneity and spectral resolution, FWHM). The optimal conditions for source preparation are provided. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Intercalation and Push‐Out Process with Spinel‐to‐Rocksalt Transition on Mg Insertion into Spinel Oxides in Magnesium Batteries

    PubMed Central

    Okamoto, Shinya; Kawaguchi, Tomoya; Kumagai, Yu; Oba, Fumiyasu; Yagi, Shunsuke; Shimokawa, Kohei; Goto, Natsumi; Doi, Takayuki; Matsubara, Eiichiro

    2015-01-01

    On the basis of the similarity between spinel and rocksalt structures, it is shown that some spinel oxides (e.g., MgCo2O4, etc) can be cathode materials for Mg rechargeable batteries around 150 °C. The Mg insertion into spinel lattices occurs via “intercalation and push‐out” process to form a rocksalt phase in the spinel mother phase. For example, by utilizing the valence change from Co(III) to Co(II) in MgCo2O4, Mg insertion occurs at a considerably high potential of about 2.9 V vs. Mg2+/Mg, and similarly it occurs around 2.3 V vs. Mg2+/Mg with the valence change from Mn(III) to Mn(II) in MgMn2O4, being comparable to the ab initio calculation. The feasibility of Mg insertion would depend on the phase stability of the counterpart rocksalt XO of MgO in Mg2X2O4 or MgX3O4 (X = Co, Fe, Mn, and Cr). In addition, the normal spinel MgMn2O4 and MgCr2O4 can be demagnesiated to some extent owing to the robust host structure of Mg1−xX2O4, where the Mg extraction/insertion potentials for MgMn2O4 and MgCr2O4 are both about 3.4 V vs. Mg2+/Mg. Especially, the former “intercalation and push‐out” process would provide a safe and stable design of cathode materials for polyvalent cations. PMID:27980965

  15. Detection of Mg-spinel bearing central peaks using M3 images: Implications for the petrogenesis of Mg-spinel

    NASA Astrophysics Data System (ADS)

    Sun, Ying; Li, Lin; Zhang, Yuanzhi

    2017-05-01

    Mg-spinel bearing lithologies, lacking abundant mafic materials, have been discovered with images acquired by the Moon Mineralogy Mapper (M3) aboard Chandrayaan-1. We conducted a systematic screening of lunar crater central peaks for the presence of Mg-spinel to address its distribution and petrogenesis. 38 Mg-spinel bearing crater central peaks were identified in this study out of 166 craters investigated. The results suggest that Mg-spinel is common in the lunar crust and appears to be extensive in the middle part of the lunar crust underneath Procellarum KREEP Terrane (PKT). Mg-spinel neither exclusively originated from deep layers (>10 km) nor necessarily coexist with the appearance of olivine or pyroxene. 15 Mg-spinel bearing central peaks originated from depth less than 10 km. Nine investigated central peaks only contain Mg-spinel and plagioclase without any detectable mafic materials. All those observations imply that the origin of Mg-spinel is possibly related to Mg-suite plutonism and assimilation between high Mg‧ magma with anorthositic crust. The extensive distribution and Mg-suite related petrogenesis indicates that Mg-spinel bearing lithologies might represent a new member of Mg-suite rocks.

  16. Quantifying the environmental impact of a Li-rich high-capacity cathode material in electric vehicles via life cycle assessment.

    PubMed

    Wang, Yuqi; Yu, Yajuan; Huang, Kai; Chen, Bo; Deng, Wensheng; Yao, Ying

    2017-01-01

    A promising Li-rich high-capacity cathode material (xLi2MnO3·(1-x)LiMn0.5Ni0.5O2) has received much attention with regard to improving the performance of lithium-ion batteries in electric vehicles. This study presents an environmental impact evaluation of a lithium-ion battery with Li-rich materials used in an electric vehicle throughout the life cycle of the battery. A comparison between this cathode material and a Li-ion cathode material containing cobalt was compiled in this study. The battery use stage was found to play a large role in the total environmental impact and high greenhouse gas emissions. During battery production, cathode material manufacturing has the highest environmental impact due to its complex processing and variety of raw materials. Compared to the cathode with cobalt, the Li-rich material generates fewer impacts in terms of human health and ecosystem quality. Through the life cycle assessment (LCA) results and sensitivity analysis, we found that the electricity mix and energy efficiency significantly influence the environmental impacts of both battery production and battery use. This paper also provides a detailed life cycle inventory, including firsthand data on lithium-ion batteries with Li-rich cathode materials.

  17. Surfactants assisted synthesis and electrochemical properties of nano-LiFePO4/C cathode materials for low temperature applications

    NASA Astrophysics Data System (ADS)

    Zheng, Fenghua; Yang, Chenghao; Ji, Xu; Hu, Dongli; Chen, Yu; Liu, Meilin

    2015-08-01

    Nano-LiFePO4/C cathode materials have been synthesized by a solid-state reaction method using Tween60-Span60 composite as surfactant and carbon source. The Tween60-Span60 composite surfactants together lead a strong space steric effect, which ensures a high surface energy and reaction kinetic of the precursors. Consequently, it contributes to the formation of uniformly distributed LiFePO4 particles coated with a thin layer of carbon. The unique structured LiFePO4/C cathode materials can deliver high electrochemical capacities of 166, 150.5 and 130.1 mAh g-1 under 0.1 C at 25, 0 and -20 °C, respectively. Moreover, the LiFePO4/C cathode materials demonstrate an excellent rate capability and cycle performance, no discernible specific discharge capacity fading has been observed after over 400 cycles under the rate of 0.1-5 C at 25 °C, or after over 100 cycles under the rate of 0.1-0.5 C at -20 °C.

  18. In-situ x-ray diffraction of layered LiCoO{sub 2}-Type cathode materials

    SciTech Connect

    Rodriguez, M.A.; Ingersoll, D.; Doughty, D.H.

    1999-12-09

    The authors have investigated LiNi{sub 0.8}Co{sub 0.2}O{sub 2} (Sumitomo) and LiNi{sub 5/8}Co{sub 1/4}Mn{sub 1/16}Al{sub 1/16}O{sub 2} (Sandia chemical preparation method) cathode powders via in-situ X-ray Diffraction and Cyclic Voltammetry using a coffee-bag type electrochemical cell. Both cathode materials did not show a monoclinic distortion during de-intercalation but sustained the hexagonal structure up to 4.3 V. The doping of Co into the LiNiO{sub 2} structure appears to stabilize this lattice as the hexagonal structure over the full range of charging (up to 4.3 V). The LiNi{sub 5/8}Co{sub 1/4}Mn{sub 1/16}Al{sub 1/16}O{sub 2} cathode material exhibited a 160 mAh/g capacity (to 4.1 V) on its 1{sup st} cycle, while displaying a much smaller volume change (as compared to LiNi{sub 0.8}Co{sub 0.2}O{sub 2}) during de-intercalation. This reduced overall volume change (2.5 vol%) may have important implications for cycle life of this material.

  19. Foamlike porous spinel Mn(x)Co(3-x)O4 material derived from Mn3[Co(CN)6]2⋅nH2O nanocubes: a highly efficient anode material for lithium batteries.

    PubMed

    Hu, Lin; Zhang, Ping; Zhong, Hao; Zheng, Xinrui; Yan, Nan; Chen, Qianwang

    2012-11-19

    A new facile strategy has been designed to fabricate spinel Mn(x)Co(3-x)O(4) porous nanocubes, which involves a morphology-conserved and pyrolysis-induced transformation of Prussian Blue Analogue Mn(3)[Co(CN)(6)](2)⋅nH(2)O perfect nanocubes. Owing to the release of CO(2) and N(x)O(y) in the process of interdiffusion, this strategy can overcome to a large extent the disadvantage of the traditional ceramic route for synthesis of spinels, and Mn(x)Co(3-x)O(4) with foamlike porous nanostructure is effectively obtained. Importantly, when evaluated as an electrode material for lithium-ion batteries, the foamlike Mn(x)Co(3-x)O(4) porous nanocubes display high specific discharge capacity and excellent rate capability. The improved electrochemical performance is attributed to the beneficial features of the particular foamlike porous nanostructure and large surface area, which reduce the diffusion length for Li(+) ions and enhance the structural integrity with sufficient void space for buffering the volume variation during the Li(+) insertion/extraction.

  20. Synthesis and characterization of nanostructured cathode materials for rechargeable lithium/lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Yang, Jingsi

    The rapidly increasing markets of portable electronic devices and electric/hybrid vehicles have raised worldwide R&D efforts in developing high-energy rechargeable lithium and lithium ion batteries. High performance intercalation cathodes are key to the success of these batteries. The nanotechnology has endowed the electrode materials with a variety of improved features as well as unique characteristics. Synthesis approaches were designed in this thesis work to utilize these advantages and investigate the exceptional phenomena raised by the nanostructured materials. A novel sol-gel method was designed for the synthesis of carbon-coated phase-pure lithium iron phosphate with submicron particle sizes and uniform size distribution. The surface carbon coating was formed in-situ through pyrolysis of the precursor gel, which improved the apparent electronic conductivity of the as prepared material to 10-2 S/cm compared with 10-9-10-10 S/cm of the pristine LiFePO 4. The favorable physical characteristics of the synthesized LiFePO 4 particles and the improved electronic conductivity through the carbon coating led to electrochemical properties comparable to the best performances reported so far. Amorphous manganese oxide cryogels with nanoarchitecture were obtained by freeze-drying Mn (IV) oxide hydrogels. The combination of the advantages of the amorphous structure and the nano-architecture of the materials gave high capacities and excellent rate capabilities. This work led to the finding of a nanocrystalline Li2MnO3-like compound with a surprising electrochemical activity, which is in sharp contrast to the microcrystalline rock-salt Li2MnO3 that has been known to be electrochemically inactive. The study highlights the possibility of qualitative difference in intercalation behavior of nanostructured intercalation compounds compared with their microcrystalline counterparts. Bismuth and copper modified amorphous manganese oxides were synthesized by aqueous coprecipitation

  1. High-capacity micrometer-sized Li2S particles as cathode materials for advanced rechargeable lithium-ion batteries.

    PubMed

    Yang, Yuan; Zheng, Guangyuan; Misra, Sumohan; Nelson, Johanna; Toney, Michael F; Cui, Yi

    2012-09-19

    Li(2)S is a high-capacity cathode material for lithium metal-free rechargeable batteries. It has a theoretical capacity of 1166 mAh/g, which is nearly 1 order of magnitude higher than traditional metal oxides/phosphates cathodes. However, Li(2)S is usually considered to be electrochemically inactive due to its high electronic resistivity and low lithium-ion diffusivity. In this paper, we discover that a large potential barrier (~1 V) exists at the beginning of charging for Li(2)S. By applying a higher voltage cutoff, this barrier can be overcome and Li(2)S becomes active. Moreover, this barrier does not appear again in the following cycling. Subsequent cycling shows that the material behaves similar to common sulfur cathodes with high energy efficiency. The initial discharge capacity is greater than 800 mAh/g for even 10 μm Li(2)S particles. Moreover, after 10 cycles, the capacity is stabilized around 500-550 mAh/g with a capacity decay rate of only ~0.25% per cycle. The origin of the initial barrier is found to be the phase nucleation of polysulfides, but the amplitude of barrier is mainly due to two factors: (a) charge transfer directly between Li(2)S and electrolyte without polysulfide and (b) lithium-ion diffusion in Li(2)S. These results demonstrate a simple and scalable approach to utilizing Li(2)S as the cathode material for rechargeable lithium-ion batteries with high specific energy.

  2. Electrochemical studies on silver bimetallic cathode materials for long life batteries

    NASA Astrophysics Data System (ADS)

    Sharma, Munish Kumar

    Due to the current energy crisis going across the globe, scientific community is continuously in search for alternate sources of energy. One of the potential solutions to handle this crisis situation is to look for electrical sources of energy such as batteries. Inside a battery, chemical energy is converted into electrical energy by means of an electrochemical reaction. At present, lithium batteries seem to be a good example due to their various advantages. Lithium batteries are currently being used to meet the power demands of electronics industry such as in laptops, digital cameras, and cellular devices etc. The reasons these batteries are in great demand today are high voltage of 3.6 V, high specific energy of 200 Wh/kg, and high calendar life of 10 years. In this research work, we focused on the lithium batteries in which Silver Vanadium Oxyphosphate (SVOP-1) Ag2VO2PO4, Silver Vanadium Oxide (SVO) Ag2V4O11, acts as the cathode and lithium metal as the anode. At present, these batteries are being used in implantable cardiac defibrillators and artificial pacemakers for biomedical applications. Therefore, it becomes important to understand the proper functioning and electrochemical mechanism of these batteries. An understanding of the reduction mechanism will help us in knowing proper functioning, performance and reliability of these battery systems. We addressed this problem by first synthesizing the SVOP-1 material using reflux and hydrothermal routes. After that, the material was characterized using Brunauer Emmett and Teller (BET), scanning electron microscopy (SEM), X-ray diffraction (XRD), particle size analyzer, optical microscopy, and differential scanning calorimetry (DSC) successfully. To understand the reduction mechanism of Li-SVOP(reflux) and Li-SVOP(hydrothermal) battery systems, we calculated thermodynamic parameters such as enthalpy, entropy and Gibb's free energy of lithium intercalation. We also did thermodynamic studies on other systems such as

  3. Metalized, three-dimensional structured oxygen cathode materials for lithium/air batteries and method for making and using the same

    DOEpatents

    Xing, Weibing; Buettner-Garrett, Josh

    2017-04-18

    This disclosure relates generally to cathode materials for electrochemical energy cells, more particularly to metal/air electrochemical energy cell cathode materials containing silver vanadium oxide and methods of making and using the same. The metal/air electrochemical energy cell can be a lithium/air electrochemical energy cell. Moreover the silver vanadium oxide can be a catalyst for one or more of oxidation and reduction processes of the electrochemical energy cell.

  4. Praseodymium and gadolinium doped ceria as a cathode material for low temperature solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Chockalingam, Rajalekshmi; Ganguli, Ashok Kumar; Basu, Suddhasatwa

    2014-03-01

    Mixed ionic electronic conducting praseodymium and gadolinium doped ceria (PrxCe0.95-xGd0.05O2-δ (0.15 ≤ x ≤ 0.40)) compositions have been studied as a cathode material for low temperature solid oxide fuel cells. Four compositions of PrxCe0.95-xGd0.05O2-δ (PCGO) have been prepared by varying the praseodymium content. Phase formation, thermal expansion, ionic conductivity, electronic conductivity, ionic transference number and electrochemical performance have been investigated. X-ray diffraction results indicate that PCGO samples crystallize in the fluorite structure, and the lattice volume decreases with increasing praseodymium content, x. The coefficient of thermal expansion increases with increasing x, and at x = 0.2 shows an optimum value of 12 × 10-6 K-1. Ionic transference number decrease while electronic conductivity increase with increasing x. It has been found that electronic contribution to the total conductivity is higher than ionic contribution for all compositions. The praseodymium doping with cerium dioxide introduces impurity bands within the ceria band gap and facilitates the electronic transition from valance band to conduction band through praseodymium impurity levels. The single cell with configuration, Pr0.2Ce0.75-xGd0.05O2-δ-Ce0.80Gd0.20O2-δ∥Ce0.80Gd0.20O2-δ∥NiO-Ce0.80Gd0.20O2-δ delivers a maximum power density of 98 mW cm-2 at 650 °C.

  5. Operando Lithium Dynamics in the Li-Rich Layered Oxide Cathode Material via Neutron Diffraction

    SciTech Connect

    Liu, Haodong; An, Ke; Venkatachalam, Subramanian; Qian, Danna; Zhang, Minghao; Meng, Ying Shirley

    2016-04-06

    Neutron diffraction under operando battery cycling is used to study the lithium and oxygen dynamics of high Li-rich Li(Lix/3Ni(3/8-3x/8)Co(1/4-x/4)Mn(3/8+7x/24)O2 (x = 0.6, HLR) and low Li-rich Li(Lix/3Ni(1/3-x/3)Co(1/3-x/3)Mn(1/3+x/3)O2 (x = 0.24, LLR) compounds that exhibit different degrees of oxygen activation at high voltage. The measured lattice parameter changes and oxygen position show largely contrasting changes for the two cathodes where the LLR exhibits larger movement of oxygen and lattice contractions in comparison to the HLR that maintains relatively constant lattice parameters and oxygen position during the high voltage plateau until the end of charge. Density functional theory calculations show the presence of oxygen vacancy during the high voltage plateau; changes in the lattice parameters and oxygen position are consistent with experimental observations. Lithium migration kinetics for the Li-rich material is observed under operando conditions for the first time to reveal the rate of lithium extraction from the lithium layer, and transition metal layer is related to the different charge and discharge characteristics. At the beginning of charging, the lithium extraction predominately occurs within the lithium layer. The lithium extraction from the lithium layer slows down and extraction from the transition metal layer evolves at a faster rate once the high voltage plateau is reached.

  6. Operando Lithium Dynamics in the Li-Rich Layered Oxide Cathode Material via Neutron Diffraction

    DOE PAGES

    Liu, Haodong; An, Ke; Venkatachalam, Subramanian; ...

    2016-04-06

    Neutron diffraction under operando battery cycling is used to study the lithium and oxygen dynamics of high Li-rich Li(Lix/3Ni(3/8-3x/8)Co(1/4-x/4)Mn(3/8+7x/24)O2 (x = 0.6, HLR) and low Li-rich Li(Lix/3Ni(1/3-x/3)Co(1/3-x/3)Mn(1/3+x/3)O2 (x = 0.24, LLR) compounds that exhibit different degrees of oxygen activation at high voltage. The measured lattice parameter changes and oxygen position show largely contrasting changes for the two cathodes where the LLR exhibits larger movement of oxygen and lattice contractions in comparison to the HLR that maintains relatively constant lattice parameters and oxygen position during the high voltage plateau until the end of charge. Density functional theory calculations show the presencemore » of oxygen vacancy during the high voltage plateau; changes in the lattice parameters and oxygen position are consistent with experimental observations. Lithium migration kinetics for the Li-rich material is observed under operando conditions for the first time to reveal the rate of lithium extraction from the lithium layer, and transition metal layer is related to the different charge and discharge characteristics. At the beginning of charging, the lithium extraction predominately occurs within the lithium layer. The lithium extraction from the lithium layer slows down and extraction from the transition metal layer evolves at a faster rate once the high voltage plateau is reached.« less

  7. One-step synthesis of graphene/polypyrrole nanofiber composites as cathode material for a biocompatible zinc/polymer battery.

    PubMed

    Li, Sha; Shu, Kewei; Zhao, Chen; Wang, Caiyun; Guo, Zaiping; Wallace, Gordon; Liu, Hua Kun

    2014-10-08

    The significance of developing implantable, biocompatible, miniature power sources operated in a low current range has become manifest in recent years to meet the demands of the fast-growing market for biomedical microdevices. In this work, we focus on developing high-performance cathode material for biocompatible zinc/polymer batteries utilizing biofluids as electrolyte. Conductive polymers and graphene are generally considered to be biocompatible and suitable for bioengineering applications. To harness the high electrical conductivity of graphene and the redox capability of polypyrrole (PPy), a polypyrrole fiber/graphene composite has been synthesized via a simple one-step route. This composite is highly conductive (141 S cm(-1)) and has a large specific surface area (561 m(2) g(-1)). It performs more effectively as the cathode material than pure polypyrrole fibers. The battery constructed with PPy fiber/reduced graphene oxide cathode and Zn anode delivered an energy density of 264 mWh g(-1) in 0.1 M phosphate-buffer saline.

  8. Inverse vulcanization of sulfur with divinylbenzene: Stable and easy processable cathode material for lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Gomez, Iñaki; Mecerreyes, David; Blazquez, J. Alberto; Leonet, Olatz; Ben Youcef, Hicham; Li, Chunmei; Gómez-Cámer, Juan Luis; Bondarchuk, Oleksandr; Rodriguez-Martinez, Lide

    2016-10-01

    Lithium-Sulfur (Li-S) battery technology is one of the promising candidates for next generation energy storage systems. Many studies have focused on the cathode materials to improve the cell performance. In this work we present a series of poly (S-DVB) copolymers synthesised by inverse vulcanization of sulfur with divinylbenzene (DVB). The poly (S-DVB) cathode shows excellent cycling performances at C/2 and C/4 current rates, respectively. It was demonstrated poly (S-DVB) copolymer containing 20% DVB did not influence the electrochemical performance of the sulfur material, compared to elemental sulfur as high specific capacities over ∼700 mAh g-1 at 500 cycles were achieved at C/4 current rate, comparable to conventional carbon-based S cathodes. However, the use of copolymer network is assumed to act firstly as sulfur reservoir and secondly as mechanical stabilizer, enhancing significantly the cycling lifetime. The Li-poly (S-DVB) cell demonstrated an extremely low degradation rate of 0.04% per cycle achieving over 1600 cycles at C/2 current rate.

  9. Effect of potassium impurities deliberately introduced into cathode materials on the electrochemical performance of a Li-O2 battery

    SciTech Connect

    Curtiss, Larry A.; Lau, Kah Chun; Zhai, Dengyun; Wen, Jianguo; Miller, Dean J.; Kang, Feiyu; Zavadil, Kevin

    2015-12-21

    Rechargeable lithium-air (Li-O-2) batteries have drawn much interest owing to their high energy density. We report on the effect of deliberately introducing potassium impurities into the cathode material on the electrochemical performance of a Li-O-2 battery. Small amounts of potassium introduced into the activated carbon (AC) cathode material in the synthesis process are found to have a dramatic effect on the performance of the Li-O-2 cell. An increased amount of potassium significantly increases capacity, cycle life, and round-trip efficiency. This improved performance is probably due to a larger amount of LiO2 in the discharge product, which is a mixture of LiO2 and Li2O2, resulting from the increase in the amount of potassium present. No substantial correlation with porosity or surface area in an AC cathode is found. Experimental and computational studies indicate that potassium can act as an oxygen reduction catalyst, which can account for the dependence of performance on the amount of potassium.

  10. Suppressing the chromium disproportionation reaction in O3-type layered cathode materials for high capacity sodium-ion batteries

    DOE PAGES

    Cao, Ming -Hui; Wang, Yong; Shadike, Zulipiya; ...

    2017-02-14

    Chromium-based layered cathode materials suffer from the irreversible disproportionation reaction of Cr4+ to Cr3+ and Cr6+, which hinders the reversible multi-electron redox of Cr ions in layered cathodes, and limits their capacity and reversibility. To address this problem, a novel O3-type layer-structured transition metal oxide of NaCr1/3Fe1/3Mn1/3O2 (NCFM) was designed and studied as a cathode material. A high reversible capacity of 186 mA h g–1 was achieved at a current rate of 0.05C in a voltage range of 1.5 to 4.2 V. X-ray diffraction revealed an O3 → (O3 + P3) → (P3 + O3'') → O3'' phase-transition pathway formore » NCFM during charge. X-ray absorption, X-ray photoelectron and electron energy-loss spectroscopy measurements revealed the electronic structure changes of NCFM during Na+ deintercalation/intercalation processes. It is confirmed that the disproportionation reaction of Cr4+ to Cr3+ and Cr6+ can be effectively suppressed by Fe3+ and Mn4+ substitution. Lastly, these results demonstrated that the reversible multi-electron oxidation/reduction of Cr ions can be achieved in NCFM during charge and discharge accompanied by CrO6 octahedral distortion and recovery.« less

  11. Suppressing the chromium disproportionation reaction in O3-type layered cathode materials for high capacity sodium-ion batteries

    SciTech Connect

    Cao, Ming-Hui; Wang, Yong; Shadike, Zulipiya; Yue, Ji-Li; Hu, Enyuan; Bak, Seong-Min; Zhou, Yong-Ning; Yang, Xiao-Qing; Fu, Zheng-Wen

    2017-01-01

    Chromium-based layered cathode materials suffer from the irreversible disproportionation reaction of Cr4+ to Cr3+ and Cr6+, which hinders the reversible multi-electron redox of Cr ions in layered cathodes, and limits their capacity and reversibility. To address this problem, a novel O3-type layer-structured transition metal oxide of NaCr1/3Fe1/3Mn1/3O2 (NCFM) was designed and studied as a cathode material. A high reversible capacity of 186 mA h g-1 was achieved at a current rate of 0.05C in a voltage range of 1.5 to 4.2 V. X-ray diffraction revealed an O3 → (O3 + P3) → (P3 + O3'') → O3'' phase-transition pathway for NCFM during charge. X-ray absorption, X-ray photoelectron and electron energy-loss spectroscopy measurements revealed the electronic structure changes of NCFM during Na+ deintercalation/intercalation processes. It is confirmed that the disproportionation reaction of Cr4+ to Cr3+ and Cr6+ can be effectively suppressed by Fe3+ and Mn4+ substitution. These results demonstrated that the reversible multi-electron oxidation/reduction of Cr ions can be achieved in NCFM during charge and discharge accompanied by CrO6 octahedral distortion and recovery.

  12. Facile electrochemical polymerization of polypyrrole film applied as cathode material in dual rotating disk photo fuel cell

    NASA Astrophysics Data System (ADS)

    Li, Kan; Zhang, Hongbo; Tang, Tiantian; Tang, Yanping; Wang, Yalin; Jia, Jinping

    2016-08-01

    Polypyrrole (PPy) film is synthesized on Ti substrate through electrochemical polymerization method and is applied as cathode material in a TiO2 NTs-PPy dual rotating disk photo fuel cell (PFC). The optimized PPy electrochemical polymerization is carried out using linear sweep voltammetry from 0 V to 1.2 V (vs. SCE) with scan rate of 0.1 V s-1, 100 circles. Sixty milliliter real textile wastewater with the initial COD and conductivity of 408 ± 6 mgO2 L-1 and 20180 μS cm-1 is treated in this PFC under UV irradiation. About 0.46 V open-circuit voltage (VOC) and 1.8-2.2 mA short-circuit current (JSC) are obtained. Due to the effective electron-hole separation effect, the COD removal rate is as high as 0.0055 min-1. Stable current and COD removal can be obtained at different output voltage. Two influence factors including rotating speed and pH are investigated. Better electricity generation performance and COD removal activity are achieved at high rotating speed and in acidic condition. In comparison with platinized cathode, though VOC is lower, similar JSC is measured. Considering the high cost of Pt, PPy is a promising alternative cathode material in PFC that can also generate electricity efficiently and stably.

  13. Ruthenium-oxide-coated sodium vanadium fluorophosphate nanowires as high-power cathode materials for sodium-ion batteries.

    PubMed

    Peng, Manhua; Li, Biao; Yan, Huijun; Zhang, Dongtang; Wang, Xiayan; Xia, Dingguo; Guo, Guangsheng

    2015-05-26

    Sodium-ion batteries are a very promising alternative to lithium-ion batteries because of their reliance on an abundant supply of sodium salts, environmental benignity, and low cost. However, the low rate capability and poor long-term stability still hinder their practical application. A cathode material, formed of RuO2 -coated Na3 V2 O2 (PO4 )2 F nanowires, has a 50 nm diameter with the space group of I4/mmm. When used as a cathode material for Na-ion batteries, a reversible capacity of 120 mAh g(-1) at 1 C and 95 mAh g(-1) at 20 C can be achieved after 1000 charge-discharge cycles. The ultrahigh rate capability and enhanced cycling stability are comparable with high performance lithium cathodes. Combining first principles computational investigation with experimental observations, the excellent performance can be attributed to the uniform and highly conductive RuO2 coating and the preferred growth of the (002) plane in the Na3 V2 O2 (PO4 )2 F nanowires.

  14. Ti/Au Cathode for Electronic transport material-free organic-inorganic hybrid perovskite solar cells

    PubMed Central

    Shi, Tongfei; Chen, Jian; Zheng, Jianqiang; Li, Xinhua; Zhou, Bukang; Cao, Huaxiang; Wang, Yuqi

    2016-01-01

    We have fabricated organic-inorganic hybrid perovskite solar cell that uses a Ti/Au multilayer as cathode and does not use electron transport materials, and achieved the highest power conversion efficiency close to 13% with high reproducibility and hysteresis-free photocurrent curves. Our cell has a Schottky planar heterojunction structure (ITO/PEDOT:PSS/perovskite/Ti/Au), in which the Ti insertion layer isolate the perovskite and Au layers, thus proving good contact between the Au and perovskite and increasing the cells’ shunt resistance greatly. Moreover, the Ti/Au cathode in direct contact with hybrid perovskite showed no reaction for a long-term exposure to the air, and can provide sufficient protection and avoid the perovskite and PEDOT:PSS layers contact with moisture. Hence, the Ti/Au based devices retain about 70% of their original efficiency after 300 h storage in the ambient environment. PMID:27995951

  15. Ti/Au Cathode for Electronic transport material-free organic-inorganic hybrid perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Shi, Tongfei; Chen, Jian; Zheng, Jianqiang; Li, Xinhua; Zhou, Bukang; Cao, Huaxiang; Wang, Yuqi

    2016-12-01

    We have fabricated organic-inorganic hybrid perovskite solar cell that uses a Ti/Au multilayer as cathode and does not use electron transport materials, and achieved the highest power conversion efficiency close to 13% with high reproducibility and hysteresis-free photocurrent curves. Our cell has a Schottky planar heterojunction structure (ITO/PEDOT:PSS/perovskite/Ti/Au), in which the Ti insertion layer isolate the perovskite and Au layers, thus proving good contact between the Au and perovskite and increasing the cells’ shunt resistance greatly. Moreover, the Ti/Au cathode in direct contact with hybrid perovskite showed no reaction for a long-term exposure to the air, and can provide sufficient protection and avoid the perovskite and PEDOT:PSS layers contact with moisture. Hence, the Ti/Au based devices retain about 70% of their original efficiency after 300 h storage in the ambient environment.

  16. Cathode material influence on the power capability and utilizable capacity of next generation lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Roscher, Michael A.; Vetter, Jens; Sauer, Dirk Uwe

    Lithium-ion cells (Li-ion) comprising lithium iron phosphate (LiFePO 4) based cathode active material are a promising battery technology for future automotive applications and consumer electronics in terms of safety, cycle and calendar lifetime and cost. Those cells comprise flat open circuit voltage (OCV) characteristics and long-term load history dependent cell impedance. In this work the special electric characteristics of LiFePO 4 based cells are elucidated, quantified and compared to Li-ion cells containing a competing cathode technology. Through pulse tests and partial cycle tests, performed with various olivine based cells, the cycling history dependency of the internal resistance and therefore on the power capability is shown. Hence, methods are illustrated to quantify this load history impact on the cells performance. Subsequently, methods to achieve a safe battery operation are elucidated. Furthermore strategies are given to obtain reliable information about the cells power capability, taking the mentioned properties into consideration.

  17. Considering Critical Factors of Li-rich Cathode and Si Anode Materials for Practical Li-ion Cell Applications.

    PubMed

    Ko, Minseong; Oh, Pilgun; Chae, Sujong; Cho, Woongrae; Cho, Jaephil

    2015-09-02

    In order to keep pace with increasing energy demands for advanced electronic devices and to achieve commercialization of electric vehicles and energy-storage systems, improvements in high-energy battery technologies are required. Among the various types of batteries, lithium ion batteries (LIBs) are among the most well-developed and commercialized of energy-storage systems. LIBs with Si anodes and Li-rich cathodes are one of the most promising alternative electrode materials for next-generation, high-energy batteries. Si and Li-rich materials exhibit high reversible capacities of <2000 mAh g(-1) and >240 mAh g(-1) , respectively. However, both materials have intrinsic drawbacks and practical limitations that prevent them from being utilized directly as active materials in high-energy LIBs. Examples for Li-rich materials include phase distortion during cycling and side reactions caused by the electrolyte at the surface, and for Si, large volume changes during cycling and low conductivity are observed. Recent progress and important approaches adopted for overcoming and alleviating these drawbacks are described in this article. A perspective on these matters is suggested and the requirements for each material are delineated, in addition to introducing a full-cell prototype utilizing a Li-rich cathode and Si anode. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Graphene-Wrapped Sulfur Particles as a Rechargeable Lithium-Sulfur Battery Cathode Material with High Capacity and Cycling Stability

    NASA Astrophysics Data System (ADS)

    Wang, Hailiang; Yang, Yuan; Liang, Yongye; Robinson, Joshua Tucker; Li, Yanguang; Jackson, Ariel; Cui, Yi; Dai, Hongjie

    2011-07-01

    We report the synthesis of a graphene-sulfur composite material by wrapping polyethyleneglycol (PEG) coated submicron sulfur particles with mildly oxidized graphene oxide sheets decorated by carbon black nanoparticles. The PEG and graphene coating layers are important to accommodating volume expansion of the coated sulfur particles during discharge, trapping soluble polysulfide intermediates and rendering the sulfur particles electrically conducting. The resulting graphene-sulfur composite showed high and stable specific capacities up to ~600mAh/g over more than 100 cycles, representing a promising cathode material for rechargeable lithium batteries with high energy density.

  19. Graphene-wrapped sulfur particles as a rechargeable lithium-sulfur battery cathode material with high capacity and cycling stability.

    PubMed

    Wang, Hailiang; Yang, Yuan; Liang, Yongye; Robinson, Joshua Tucker; Li, Yanguang; Jackson, Ariel; Cui, Yi; Dai, Hongjie

    2011-07-13

    We report the synthesis of a graphene-sulfur composite material by wrapping poly(ethylene glycol) (PEG) coated submicrometer sulfur particles with mildly oxidized graphene oxide sheets decorated by carbon black nanoparticles. The PEG and graphene coating layers are important to accommodating volume expansion of the coated sulfur particles during discharge, trapping soluble polysulfide intermediates, and rendering the sulfur particles electrically conducting. The resulting graphene-sulfur composite showed high and stable specific capacities up to ∼600 mAh/g over more than 100 cycles, representing a promising cathode material for rechargeable lithium batteries with high energy density.

  20. Mechanism of high luminous efficacy in plasma display panel with high secondary electron emission coefficient cathode material analyzed through three-dimensional fluid model simulation

    SciTech Connect

    Kwon, Ohyung; Lee, Tae-Ho; Cheong, Hee-Woon; Whang, Ki-Woong; Bae, Hyun Sook; Jung, Hae-Yoon

    2011-08-15

    The mechanism to realize high luminous efficacy in a plasma display panel fabricated with a cathode material possessing a high secondary electron emission coefficient ({gamma}) for Ne and Xe ions was studied via three-dimensional numerical simulation. When a high {gamma} cathode material is used, the increased electron heating efficacy is responsible for increasing vacuum ultraviolet (VUV) efficacy with 10% Xe content gas. However, the continued availability of sufficient secondary electrons during the dynamic moving phase of the cathode sheath in which the electric field remains weakened causes increasing VUV efficacy with 30% Xe content gas. It was found that the improvement of the luminous efficacy of the plasma display panel with a high {gamma} cathode material is maximized under the condition of high Xe content gas because of the simultaneous increase of the electron heating efficacy and Xe excitation efficacy.

  1. Thermoelectric Properties of Selenides Spinels

    NASA Technical Reports Server (NTRS)

    Snyder, G.; Caillat, T.; Fleurial, J-P.

    2000-01-01

    Many compounds with the spinel structure type have been analyzed for their thermoelectric properties. Published data was used to augment experimental results presented here to select promising thermoelectric spinels.

  2. Material/element-dependent fluorescence-yield modes on soft X-ray absorption spectroscopy of cathode materials for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Asakura, Daisuke; Hosono, Eiji; Nanba, Yusuke; Zhou, Haoshen; Okabayashi, Jun; Ban, Chunmei; Glans, Per-Anders; Guo, Jinghua; Mizokawa, Takashi; Chen, Gang; Achkar, Andrew J.; Hawthron, David G.; Regier, Thomas Z.; Wadati, Hiroki

    2016-03-01

    We evaluate the utilities of fluorescence-yield (FY) modes in soft X-ray absorption spectroscopy (XAS) of several cathode materials for Li-ion batteries. In the case of total-FY (TFY) XAS for LiNi0.5Mn1.5O4, the line shape of the Mn L3-edge XAS was largely distorted by the self-absorption and saturation effects, while the distortions were less pronounced at the Ni L3 edge. The distortions were suppressed for the inverse-partial-FY (IPFY) spectra. We found that, in the cathode materials, the IPFY XAS is highly effective for the Cr, Mn, and Fe L edges and the TFY and PFY modes are useful enough for the Ni L edge which is far from the O K edge.

  3. Transmission electron microscopy (TEM) investigations of Mn-oxide rich cathodic material from spent disposable alkaline batteries.

    PubMed

    Krekeler, Mark P S

    2008-11-01

    Transmission electron microscopy (TEM) techniques were used to investigate the spent cathodic material of a single common brand of disposable alkaline batteries. Mn-oxide particles are anhedral and irregular in shape and compose an estimated 99-95% of the < 10 microm size fraction of sample material. Diameters of particles vary widely and typically are between 50 nm and 3 microm; however, most particles are approximately 200-400 nm in diameter. Chemical composition varies for Mn-oxide particles with concentrations being SiO2 (0.00-1.52 wt%), TiO2 (0.49-4.58 wt%), MnO (65.85-92.06 wt%), ZnO (1.00-7.53 wt%), K2O (4.97-20.48 wt%) and SO3 (0.43-2.21 wt%). Discrete prismatic zinc crystals occur and vary from a maximum of approximately 0.8 microm long x 0.15 microm wide, to 100 nm long x 20 nm wide. Titanium metal was also observed in samples and composes approximately 0.25-1.0% of the < 10 microm size fraction of sample material. Results of this study suggest that battery components may be recycled in some special applications. Examples are low energy-low material requirement products such as paint pigments and Zn nanoparticles. This investigation provides detailed constraints on the nature of spent cathodic materials to improve existing recycling methods and develop new technologies.

  4. Microstructure control of SOFC cathode material: The role of dispersing agent

    NASA Astrophysics Data System (ADS)

    Ismail, Ismariza; Jani, Abdul Mutalib Md; Osman, Nafisah

    2017-09-01

    In the present works, La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathode powders were synthesized by a sol-gel method with the aid of ethylene glycol which served as the dispersing agent. The phase formation and morphology of the powders were examined by X-Ray diffractometer (XRD) and field emission scanning electron microscopy (FESEM), respectively. The electrochemical properties of the synthesized cathode were obtained using an electrochemical impedance spectroscopy (EIS). The characteristic peaks for LSCF phase appears in the X-ray diffractogram after calcined at 500 °C and complete formation of LSCF single phase was attained at 700 °C. FESEM micrographs showed the presence of spherical particles of the powders with approximate particle size between 10 to 60 nm along with agglomerate morphologies. Well dispersed particles and fewer aggregates were observed for samples prepared with addition of ethylene glycol as the synthesizing aid. The surface area obtained for powder sample prepared with the aid of dispersing agent is 12.0 m2g-1. The EIS measurement results depicts a lower area specific resistance (ASR) obtained for sample prepared with addition of the ethylene glycol as compared to the pristine sample. The present results encourage the optimization of the cathode particle design in order to further improve the cathode performance.

  5. Modified synthesis of [Fe/LiF/C] nanocomposite, and its application as conversion cathode material in lithium batteries

    NASA Astrophysics Data System (ADS)

    Prakash, Raju; Wall, Clemens; Mishra, Ajay Kumar; Kübel, Christian; Ghafari, Mohammad; Hahn, Horst; Fichtner, Maximilian

    In an attempt to enhance the energy storage capacity and discharge voltage, a new cathode material based on ferrocene and LiF for lithium-ion batteries has been explored [Fe/LiF/C] nanocomposite (1) has been synthesized by pyrolysis of a ferrocene/LiF mixture at 700 °C using a rotating quartz tube setup in a furnace. The structure and morphology of the composite were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), Brunauer-Emmer-Teller (BET) analysis, Raman, and Mössbauer spectroscopy. The nanocomposite is composed of well-defined nanotubes which are interlinked by graphitic shell-type structures containing uniformly distribution of Fe, Fe-C, and LiF nanoparticles. The binder-free nanocomposite cathode showed enhanced electrochemical performance with the reversible specific capacity of 230 mAh g -1 (1.3-4.3 V) at 20.8 mA g -1 at room temperature. It exhibited a remarkable cyclic stability and good rate capability performances. The morphology of 1 was changed by ball milling, and the resulting nanocomposite 2 did not show any cyclic stability as a cathode. Thus, the cyclic stability and rate capability performances of 1 were attributed to its structure and morphology.

  6. Nickel Hydroxide-Modified Sulfur/Carbon Composite as a High-Performance Cathode Material for Lithium Sulfur Battery.

    PubMed

    Niu, Xiao-Qing; Wang, Xiu-Li; Xie, Dong; Wang, Dong-Huang; Zhang, Yi-Di; Li, Yi; Yu, Ting; Tu, Jiang-Ping

    2015-08-05

    Tailored sulfur cathode is vital for the development of a high performance lithium-sulfur (Li-S) battery. A surface modification on the sulfur/carbon composite would be an efficient strategy to enhance the cycling stability. Herein, we report a nickel hydroxide-modified sulfur/conductive carbon black composite (Ni(OH)2@S/CCB) as the cathode material for the Li-S battery through the thermal treatment and chemical precipitation method. In this composite, the sublimed sulfur is stored in the CCB, followed by a surface modification of Ni(OH)2 nanoparticles with size of 1-2 nm. As a cathode for the Li-S battery, the as-prepared Ni(OH)2@S/CCB electrode exhibits better cycle stability and higher rate discharge capacity, compared with the bare S/CCB electrode. The improved performance is largely due to the introduction of Ni(OH)2 surface modification, which can effectively suppress the "shuttle effect" of polysulfides, resulting in enhanced cycling life and higher capacity.

  7. H2V3O8 Nanowires as High-Capacity Cathode Materials for Magnesium-Based Battery.

    PubMed

    Tang, Han; Xu, Nuo; Pei, Cunyuan; Xiong, Fangyu; Tan, Shuangshuang; Luo, Wen; An, Qinyou; Mai, Liqiang

    2017-08-30

    Magnesium-based batteries have received much attention as promising candidates to next-generation batteries because of high volumetric capacity, low price, and dendrite-free property of Mg metal. Herein, we reported H2V3O8 nanowire cathode with excellent electrochemical property in magnesium-based batteries. First, it shows a satisfactory magnesium storage ability with 304.2 mA h g(-1) capacity at 50 mA g(-1). Second, it possesses a high-voltage platform of ∼2.0 V vs Mg/Mg(2+). Furthermore, when evaluated as a cathode material for magnesium-based hybrid Mg(2+)/Li(+) battery, it exhibits a high specific capacity of 305.4 mA h g(-1) at 25 mA g(-1) and can be performed in a wide working temperature range (-20 to 55 °C). Notably, the insertion-type ion storage mechanism of H2V3O8 nanowires in hybrid Mg(2+)/Li(+) batteries are investigated by ex situ X-ray diffraction and Fourier transform infrared. This research demonstrates that the H2V3O8 nanowire cathode is a potential candidate for high-performance magnesium-based batteries.

  8. Is alpha-V2O5 a cathode material for Mg insertion batteries?

    SciTech Connect

    Sa, Niya; Wang, Hao; Proffit, Danielle L.; Lipson, Albert L.; Key, Baris; Liu, Miao; Feng, Zhenxing; Fister, Timothy T.; Ren, Yang; Sun, Cheng-Jun; Vaughey, John T.; Fenter, Paul A.; Persson, Kristin A.; Burrell, Anthony K.

    2016-08-01

    When designing a high energy density battery, one of the critical features is a high voltage, high capacity cathode material. In the development of Mg batteries, oxide cathodes that can reversibly intercalate Mg, while at the same time being compatible with an electrolyte that can deposit Mg reversibly are rare. Herein, we report the compatibility of Mg anodes with a-V2O5 by employing magnesium bis(trifluoromethane sulfonyl)imide in diglyme electrolytes at very low water levels. Electrolytes that contain a high water level do not reversibly deposit Mg, but interestingly these electrolytes appear to enable much higher capacities for an a-V2O5 cathode. Solid state NMR indicates that the major source of the higher capacity in high water content electrolytes originates from reversible proton insertion. In contrast, we found that lowering the water level of the magnesium bis(trifluoromethane sulfonyl)imide in diglyme electrolyte is critical to achieve reversible Mg deposition and direct evidence for reversible Mg intercalation is shown. Findings we report here elucidate the role of proton intercalation in water-containing electrolytes and clarify numerous conflicting reports of Mg insertion into a-V2O5.

  9. Effects of cathode materials on the characteristics of electrolyte supported micro-tubular solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Hsieh, Wen-Shuo; Lin, Pang; Wang, Sea-Fue

    2014-05-01

    The effects of the GDC-LSCF (Ce0.8Gd0.2O0-δ-La0.6Sr0.4Co0.2Fe0.8O3-δ) cathode layer and the GDC interlayer on the electrochemical performance of the ScSZ (Zr0.8Sc0.2O2-δ) electrolyte supported (≈270 μm) micro-tubular SOFC cells are investigated in this study. Material formulation and sintering profile for fabricating the micro-tubular SOFC cells are developed to avoid physical defects caused by the large sintering shrinkage mismatch among the layers. Cell B (with the LSCF-GDC composite cathode layer and the GDC interlayer) reports an ohmic resistance slightly higher than that of Cell A (with the GDC-La0.8Sr0.2MnO3-δ, i.e. LSM, composite cathode), while its polarization resistance emerges to be significantly smaller than that of Cell A. In terms of cell performance, Cell B demonstrates an OCV value (>1.07 V) similar to that of Cell A and a maximum power density (0.26 W cm-2) 44.4% greater than that of Cell A (0.17 W cm-2) at 850 °C. It can thus be concluded that using the LSCF-GDC composite-cathode layer and inserting the GDC interlayer help reduce the total cell impedance, thereby improving the power density of the tubular cells.

  10. Suppressing capacity fading and voltage decay of Li-rich layered cathode material by a surface nano-protective layer of CoF2 for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Chong, Shaokun; Chen, Yuanzhen; Yan, Wuwei; Guo, Shengwu; Tan, Qiang; Wu, Yifang; Jiang, Tao; Liu, Yongning

    2016-11-01

    Li-rich layered oxides have been regarded as valuable cathode materials for high energy density lithium-ion batteries. However, high initial irreversible capacity, bad rate capability, as well as serious capacity fading and voltage decay hinder their commercial application. In this paper, a nano CoF2 protective layer is coated on the surface of Li1.2Ni0.2Mn0.6O2 via a facial wet chemistry method. A high initial discharge capacity of 264.4 mAh g-1 is obtained for 0.5% CoF2-coated sample and 259.1 mAh g-1 for 1% CoF2-coated sample owing to the suppression of irreversible release of O2 and the contribution of electrochemical conversion of CoF2/LiF. Furthermore, 1% CoF2-coated sample exhibits the excellent rate capability of 167.5 mAh g-1 at 5 C rate, the superior cycling stability with the capacity retention of 241.0 mAh g-1 and the ameliorative voltage drop of 0.312 V at 0.1C after 100 cycles. The enhanced rate performance as well as stability of capacity and voltage can be attributed to the nano coatings which inhibit the electrolyte-electrode side reaction, enhance the electrochemical kinetics and mitigate structure transition from layered to spinel phase.

  11. Influence of Parameters of the Glow Discharge on Change of Structure and the Isotope Composition of the Cathode Materials

    NASA Astrophysics Data System (ADS)

    Savvatimova, I. B.; Gavritenkov, D. V.

    Results of examinations of changes in structure, element, and isotope composition of cathodes after the glow discharge exposure in hydrogen, deuterium, argon, and xenon are submitted. The voltage of the discharge was less than 1000 V and the current was 5-150 mA. Samples before and after ions bombardment in the glow discharge were explored by the methods of mass spectrometry: the secondary ions (SIMS), the secondary ions with additional ionization of neutral sprayed particles (SNMS), spark (SMS), and thermo-ionization (TIMS), and also methods of energy dispersion X-ray spectral analysis (EDX). The alpha-, beta-, gamma- emission, and gamma- spectrometry for radioactive uranium specimens were also carried out before and after experiments in the glow discharge. Changes in structure, isotope, and element composition of the cathode samples depend on current density, integrated ions flow (fluence of ions), kind of irradiating ions and other experimental conditions. Attempts are made to estimate qualitatively and quantitatively the role of each of the parameters on intensity of the observed changes in cathode composition. It is shown that the maximum changes in structure, chemical and isotope composition of the cathode material occur in "hot points," such as craters from microexplosions, phase segregations, blisters and other new formations. Various methods of the analysis revealed that the basic elements Mg, O, Si, Al, and Ca with quantities up to per cents and more were prevailing in these zones and not found out before experiment. The greatest changes of the isotope relations were observed for iron, calcium, silicon, chromium after experiments with pulsing current. EDX method finds out the elements missing in the samples before experiment such as cadmium, strontium, tin. The isotopes with mass number 59 (Co 100%), 55 (Mn 100%), 45 (Sc 100%) are also not found in initial samples and background measurement by TIMS method. Results of changes in the element and isotope

  12. Graphene–Selenium Hybrid Microballs as Cathode Materials for High-performance Lithium–Selenium Secondary Battery Applications

    PubMed Central

    Youn, Hee-Chang; Jeong, Jun Hui; Roh, Kwang Chul; Kim, Kwang-Bum

    2016-01-01

    In this study, graphene–selenium hybrid microballs (G–SeHMs) are prepared in one step by aerosol microdroplet drying using a commercial spray dryer, which represents a simple, scalable continuous process, and the potential of the G–SeHMs thus prepared is investigated for use as cathode material in applications of lithium–selenium secondary batteries. These morphologically unique graphene microballs filled with Se particles exhibited good electrochemical properties, such as high initial specific capacity (642 mA h g−1 at 0.1 C, corresponding to Se electrochemical utilisation as high as 95.1%), good cycling stability (544 mA h g−1 after 100 cycles at 0.1 C; 84.5% retention) and high rate capability (specific capacity of 301 mA h g−1 at 5 C). These electrochemical properties are attributed to the fact that the G–SeHM structure acts as a confinement matrix for suppressing the dissolution of polyselenides in the organic electrolyte, as well as an electron conduction path for increasing the transport rate of electrons for electrochemical reactions. Notably, based on the weight of hybrid materials, electrochemical performance is considerably better than that of previously reported Se-based cathode materials, attributed to the high Se loading content (80 wt%) in hybrid materials. PMID:27480798

  13. Graphene-Selenium Hybrid Microballs as Cathode Materials for High-performance Lithium-Selenium Secondary Battery Applications.

    PubMed

    Youn, Hee-Chang; Jeong, Jun Hui; Roh, Kwang Chul; Kim, Kwang-Bum

    2016-08-02

    In this study, graphene-selenium hybrid microballs (G-SeHMs) are prepared in one step by aerosol microdroplet drying using a commercial spray dryer, which represents a simple, scalable continuous process, and the potential of the G-SeHMs thus prepared is investigated for use as cathode material in applications of lithium-selenium secondary batteries. These morphologically unique graphene microballs filled with Se particles exhibited good electrochemical properties, such as high initial specific capacity (642 mA h g(-1) at 0.1 C, corresponding to Se electrochemical utilisation as high as 95.1%), good cycling stability (544 mA h g(-1) after 100 cycles at 0.1 C; 84.5% retention) and high rate capability (specific capacity of 301 mA h g(-1) at 5 C). These electrochemical properties are attributed to the fact that the G-SeHM structure acts as a confinement matrix for suppressing the dissolution of polyselenides in the organic electrolyte, as well as an electron conduction path for increasing the transport rate of electrons for electrochemical reactions. Notably, based on the weight of hybrid materials, electrochemical performance is considerably better than that of previously reported Se-based cathode materials, attributed to the high Se loading content (80 wt%) in hybrid materials.

  14. Graphene–Selenium Hybrid Microballs as Cathode Materials for High-performance Lithium–Selenium Secondary Battery Applications

    NASA Astrophysics Data System (ADS)

    Youn, Hee-Chang; Jeong, Jun Hui; Roh, Kwang Chul; Kim, Kwang-Bum

    2016-08-01

    In this study, graphene–selenium hybrid microballs (G–SeHMs) are prepared in one step by aerosol microdroplet drying using a commercial spray dryer, which represents a simple, scalable continuous process, and the potential of the G–SeHMs thus prepared is investigated for use as cathode material in applications of lithium–selenium secondary batteries. These morphologically unique graphene microballs filled with Se particles exhibited good electrochemical properties, such as high initial specific capacity (642 mA h g‑1 at 0.1 C, corresponding to Se electrochemical utilisation as high as 95.1%), good cycling stability (544 mA h g‑1 after 100 cycles at 0.1 C 84.5% retention) and high rate capability (specific capacity of 301 mA h g‑1 at 5 C). These electrochemical properties are attributed to the fact that the G–SeHM structure acts as a confinement matrix for suppressing the dissolution of polyselenides in the organic electrolyte, as well as an electron conduction path for increasing the transport rate of electrons for electrochemical reactions. Notably, based on the weight of hybrid materials, electrochemical performance is considerably better than that of previously reported Se-based cathode materials, attributed to the high Se loading content (80 wt%) in hybrid materials.

  15. Atomic layer deposition of amorphous oxygen-deficient TiO2-x on carbon nanotubes as cathode materials for lithium-air batteries

    NASA Astrophysics Data System (ADS)

    Yang, Jingbo; Ma, Dingtao; Li, Yongliang; Zhang, Peixin; Mi, Hongwei; Deng, Libo; Sun, Lingna; Ren, Xiangzhong

    2017-08-01

    The amorphous oxygen-deficient TiO2-x thin layer coated carbon nanotubes (CNTs) are synthesized by atomic layer deposition and employed as cathode materials for lithium-air battery. The cathode demonstrates high electrocatalytic activity toward electrode reactions, resulting from the introduction of oxygen-deficient TiO2-x into the nanocomposites. It is found that the intrinsically isotropic nature of amorphous TiO2 which a certain amount of Ti3.5+ and Ti3+ can improve the catalytic activity. Consequently, the battery with the corresponded CNT@TiO2-x cathode shows high discharge/charge capacities and good cycling performance, which the cyclic retention of more than 90 cycles are achieved, while with the pristine CNTs only 50 cycles are obtained. This study provides an approach to fabricate cathode materials for lithium-air battery and moreover clarifies the influence of oxygen vacancies of TiO2 on the electrochemical performance.

  16. A New CuO-Fe2 O3 -Mesocarbon Microbeads Conversion Anode in a High-Performance Lithium-Ion Battery with a Li1.35 Ni0.48 Fe0.1 Mn1.72 O4 Spinel Cathode.

    PubMed

    Di Lecce, Daniele; Verrelli, Roberta; Campanella, Daniele; Marangon, Vittorio; Hassoun, Jusef

    2017-01-10

    A ternary CuO-Fe2 O3 -mesocarbon microbeads (MCMB) conversion anode was characterized and combined with a high-voltage Li1.35 Ni0.48 Fe0.1 Mn1.72 O4 spinel cathode in a lithium-ion battery of relevant performance in terms of cycling stability and rate capability. The CuO-Fe2 O3 -MCMB composite was prepared by using high-energy milling, a low-cost pathway that leads to a crystalline structure and homogeneous submicrometrical morphology as revealed by XRD and electron microscopy. The anode reversibly exchanges lithium ions through the conversion reactions of CuO and Fe2 O3 and by insertion into the MCMB carbon. Electrochemical tests, including impedance spectroscopy, revealed a conductive electrode/electrolyte interface that enabled the anode to achieve a reversible capacity value higher than 500 mAh g(-1) when cycled at a current of 120 mA g(-1) . The remarkable stability of the CuO-Fe2 O3 -MCMB electrode and the suitable characteristics in terms of delivered capacity and voltage-profile retention allowed its use in an efficient full lithium-ion cell with a high-voltage Li1.35 Ni0.48 Fe0.1 Mn1.72 O4 cathode. The cell had a working voltage of 3.6 V and delivered a capacity of 110 mAh gcathode(-1) with a Coulombic efficiency above 99 % after 100 cycles at 148 mA gcathode(-1) . This relevant performances, rarely achieved by lithium-ion systems that use the conversion reaction, are the result of an excellent cell balance in terms of negative-to-positive ratio, favored by the anode composition and electrochemical features.

  17. Effect of Transition Metal Ordering on the Electronic Properties of LiNi1 - y - xCoyMnxO2 Cathode Materials for Li-ion Batteries

    NASA Astrophysics Data System (ADS)

    Longo, Roberto; Kong, Fantai; Kc, Santosh; Yeon, Dong-Hee; Yoon, Jaegu; Park, Jin-Hwan; Doo, Seok-Kwang; Cho, Kyeongjae; MSL Team; SAIT Team

    2015-03-01

    Current Li-ion batteries use layered oxides as cathode materials, specially LiCoO2 or LiNi1 - y - xCoyMnxO2(NCM), and graphite as anode. Co layered oxides suffer from the high cost and toxicity of cobalt, together with certain instability at high operational temperatures. To overcome these difficulties, the synthesis of novel materials composed of layered oxides with different sets of Transition Metals (TM) has become the most successful way to solve the particular drawbacks of every single-oxide family. Although layered materials can deliver larger capacity than other families of cathode materials, the energy density has yet to be increased in order to match the expectations deposited on the NCM oxides. To acquire a high capacity, they need to be cycled at high operational voltages, resulting in voltage and capacity fading over a large number of cycles. In this work, we examine the phase diagram of the Li-Ni-Co-Mn-O system and the effect of TM ordering on the electronic properties of NCM cathode materials, using density-functional theory. Our findings will provide conceptual guidance in the experimental search for the mechanisms driving the voltage and capacity fading of the NCM family of cathode materials, in an attempt to solve such structural instability problems and, thus, improving the performance of the NCM cathode materials. This work was supported by Samsung GRO project.

  18. Construction of tubular polypyrrole-wrapped biomass-derived carbon nanospheres as cathode materials for lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Yu, Qiuhong; Lu, Yang; Peng, Tao; Hou, Xiaoyi; Luo, Rongjie; Wang, Yange; Yan, Hailong; Liu, Xianming; Kim, Jang-Kyo; Luo, Yongsong

    2017-03-01

    A promising hybrid material composed of tubular polypyrrole (T-PPy)-wrapped monodisperse biomass-derived carbon nanospheres (BCSs) was first synthesized successfully via a simple hydrothermal approach by using watermelon juice as the carbon source, and further used as an anchoring object for sulfur (S) of lithium-sulfur (Li-S) batteries. The use of BCSs with hydrophilic nature as a framework could provide large interface areas between the active materials and electrolyte, and improve the dispersion of T-PPy, which could help in the active material utilization. As a result, BCS@T-PPy/S as a cathode material exhibited a high capacity of 1143.6 mA h g-1 and delivered a stable capacity up to 685.8 mA h g-1 after 500 cycles at 0.5 C, demonstrating its promising application for rechargeable Li-S batteries.

  19. Research Progress in Improving the Cycling Stability of High-Voltage LiNi0.5Mn1.5O4 Cathode in Lithium-Ion Battery

    NASA Astrophysics Data System (ADS)

    Xu, XiaoLong; Deng, SiXu; Wang, Hao; Liu, JingBing; Yan, Hui

    2017-04-01

    High-voltage lithium-ion batteries (HVLIBs) are considered as promising devices of energy storage for electric vehicle, hybrid electric vehicle, and other high-power equipment. HVLIBs require their own platform voltages to be higher than 4.5 V on charge. Lithium nickel manganese spinel LiNi0.5Mn1.5O4 (LNMO) cathode is the most promising candidate among the 5 V cathode materials for HVLIBs due to its flat plateau at 4.7 V. However, the degradation of cyclic performance is very serious when LNMO cathode operates over 4.2 V. In this review, we summarize some methods for enhancing the cycling stability of LNMO cathodes in lithium-ion batteries, including doping, cathode surface coating, electrolyte modifying, and other methods. We also discuss the advantages and disadvantages of different methods.

  20. Template-Assisted Hydrothermal Synthesis of Li₂MnSiO₄ as a Cathode Material for Lithium Ion Batteries.

    PubMed

    Xie, Man; Luo, Rui; Chen, Renjie; Wu, Feng; Zhao, Taolin; Wang, Qiuyan; Li, Li

    2015-05-27

    Lithium manganese silicate (Li2MnSiO4) is an attractive cathode material with a potential capacity above 300 mA h g(-1) if both lithium ions can be extracted reversibly. Two drawbacks of low electronic conductivity and structural collapse could be overcome by a conductive surface coating and a porous structure. Porous morphology with inner mesopores offers larger surface area and shorter ions diffusion pathways and also buffers the volume changes during lithium insertion and extraction. In this paper, mesoporous Li2MnSiO4 (M-Li2MnSiO4) prepared using MCM-41 as template through a hydrothermal route is compared to a sample of bulk Li2MnSiO4 (B-Li2MnSiO4) using silica as template under the same conditions. Also, in situ carbon coating technique was used to improve the electronic conductivity of M-Li2MnSiO4. The physical properties of these cathode materials were further characterized by SEM, XRD, FTIR, and N2 adsorption-desorption. It is shown that M-Li2MnSiO4 exhibits porous structure with pore sizes distributed in the range 9-12 nm, and when used as cathode electrode material, M-Li2MnSiO4 exhibits enhanced specific discharge capacity of 193 mA h g(-1) at a constant current of 20 mA g(-1) compared with 120.1 mA h g(-1) of B-Li2MnSiO4. This is attributed to the porous structure which allows the electrolyte to penetrate into the particles easily. And carbon-coated M-Li2MnSiO4 shows smaller charge transfer resistance and higher capacity of 217 mA h g(-1) because carbon coating retains the porous structure and enhances the electrical conductivity.

  1. Thin film passivation of laser generated 3D micro patterns in lithium manganese oxide cathodes

    NASA Astrophysics Data System (ADS)

    Pröll, J.; Kohler, R.; Bruns, M.; Oberst, V.; Weidler, P. G.; Heißler, S.; Kübel, C.; Scherer, T.; Prang, R.; Seifert, H. J.; Pfleging, W.

    2013-03-01

    The increasing need for long-life lithium-ion batteries requires the further development of electrode materials. Especially on the cathode side new materials or material composites are needed to increase the cycle lifetime. On the one hand, spinel-type lithium manganese oxide is a promising candidate to be used as cathode material due to its non-toxicity, low cost and good thermal stability. On the other hand, the spinel structure suffers from change in the oxidation state of manganese during cycling which is also accompanied by loss of active material into the liquid electrolyte. The general trend is to enhance the active surface area of the cathode in order to increase lithium-ion mobility through the electrode/electrolyte interface, while an enhanced surface area will also promote chemical degradation. In this work, laser microstructuring of lithium manganese oxide thin films was applied in a first step to increase the active surface area. This was done by using 248 nm excimer laser radiation and chromium/quartz mask imaging techniques. In a second step, high power diode laser-annealing operating at a wavelength of 940 nm was used for forming a cubic spinel-like battery phase. This was verified by means of Raman spectroscopy and cyclic voltammetric measurements. In a last step, the laser patterned thin films were coated with indium tin oxide (ITO) layers with a thickness of 10 nm to 50 nm. The influence of the 3D surface topography as well as the ITO thickness on the electrochemical performance was studied by cyclic voltammetry. Post-mortem studies were carried out by using scanning electron microscopy and focused ion beam analysis.

  2. Preliminary study of structural changes in Li2MnSiO4 cathode material during electrochemical reaction

    NASA Astrophysics Data System (ADS)

    Świętosławski, Michał; Molenda, Marcin; Gajewska, Marta

    2016-06-01

    In this paper, we present exsitu observations of a structure of particular Li2MnSiO4 grains at different states of charge (SOC). The goal of these studies is structural analysis of Li2MnSiO4 cathode material for Li-ion batteries at different stages of electrochemical reaction using transmission electron microscopy. Performed analysis suggests that amorphization process of Li2MnSiO4 is not directly connected with lithium ions deintercalation but with additional electrochemical reactions running in the working cell.

  3. Tuning charge–discharge induced unit cell breathing in layer-structured cathode materials for lithium-ion batteries

    SciTech Connect

    Zhou, Yong-Ning; Ma, Jun; Hu, Enyuan; Yu, Xiqian; Gu, Lin; Nam, Kyung -Wan; Chen, Liquan; Wang, Zhaoxiang; Yang, Xiao -Qing

    2014-11-18

    Through a systematic study of lithium molybdenum trioxide (Li2MoO3), a new ‘unit cell breathing’ mechanism is introduced based on both crystal and electronic structural changes of transition metal oxide cathode materials during charge–discharge: For widely used LiMO2 (M = Co, Ni, Mn), lattice parameters, a and b, contracts during charge. However, for Li2MoO3, such changes are in opposite directions. Metal–metal bonding is used to explain such ‘abnormal’ behaviour and a generalized hypothesis is developed. The expansion of M–M bond becomes the controlling factor for a(b) evolution during charge, in contrast to the shrinking M–O as controlling factor in ‘normal’ materials. The cation mixing caused by migration of Mo ions at higher oxidation state provides the benefits of reducing the c expansion range in early stage of charging and suppressing the structure collapse at high voltage charge. These results open a new strategy for designing and engineering layered cathode materials for high energy density lithium-ion batteries.

  4. Cathode material comparison of thermal runaway behavior of Li-ion cells at different state of charges including over charge

    NASA Astrophysics Data System (ADS)

    Mendoza-Hernandez, Omar Samuel; Ishikawa, Hiroaki; Nishikawa, Yuuki; Maruyama, Yuki; Umeda, Minoru

    2015-04-01

    The analysis of Li-ion secondary cells under outstanding conditions, as overcharge and high temperatures, is important to determine thermal abuse characteristics of electroactive materials and precise risk assessments on Li-ion cells. In this work, the thermal runaway behavior of LiCoO2 and LiMn2O4 cathode materials were compared at different state of charges (SOCs), including overcharge, by carrying out accelerating rate calorimetry (ARC) measurements using 18650 Li-ion cells. Onset temperatures of self-heating reactions and thermal runaway behavior were identified, and by using these onset points thermal mapping plots were made. We were able to identify non-self-heating, self-heating and thermal runaway regions as a function of state of charge and temperature. The cell using LiMn2O4 cathode material was found to be more thermally stable than the cell using LiCoO2. In parallel with the ARC measurements, the electrochemical behavior of the cells was monitored by measuring the OCV and internal resistance of the cells. The electrochemical behavior of the cells showed a slightly dependency on SOC.

  5. Tuning charge–discharge induced unit cell breathing in layer-structured cathode materials for lithium-ion batteries

    DOE PAGES

    Zhou, Yong-Ning; Ma, Jun; Hu, Enyuan; ...

    2014-11-18

    Through a systematic study of lithium molybdenum trioxide (Li2MoO3), a new ‘unit cell breathing’ mechanism is introduced based on both crystal and electronic structural changes of transition metal oxide cathode materials during charge–discharge: For widely used LiMO2 (M = Co, Ni, Mn), lattice parameters, a and b, contracts during charge. However, for Li2MoO3, such changes are in opposite directions. Metal–metal bonding is used to explain such ‘abnormal’ behaviour and a generalized hypothesis is developed. The expansion of M–M bond becomes the controlling factor for a(b) evolution during charge, in contrast to the shrinking M–O as controlling factor in ‘normal’ materials.more » The cation mixing caused by migration of Mo ions at higher oxidation state provides the benefits of reducing the c expansion range in early stage of charging and suppressing the structure collapse at high voltage charge. These results open a new strategy for designing and engineering layered cathode materials for high energy density lithium-ion batteries.« less

  6. Unraveling the Complex Delithiation and Lithiation Mechanisms of the High Capacity Cathode Material V6O13

    DOE PAGES

    Meng, Wei; Pigliapochi, Roberta; Bayley, Paul M.; ...

    2017-06-05

    V6O13 is a promising Li-ion battery cathode material for use in the high temperature oil field environment. The material exhibits a high capacity, and the voltage profile contains several plateaus associated with a series of complex structural transformations, which are not fully understood. The underlying mechanisms are central to understanding and improving the performance of V6O13-based rechargeable batteries. In this study, we present in situ X-ray diffraction data that highlight an asymmetric six-step discharge and five step charge process, due to a phase that is only formed on discharge. The LixV6O13 unit cell expands sequentially in c, b, and amore » directions during discharge and reversibly contracts back during charge. The process is associated with change of Li ion positions as well as charge ordering in LixV6O13. Density functional theory calculations give further insight into the electronic structures and preferred Li positions in the different structures formed upon cycling, particularly at high lithium contents, where no prior structural data are available. Lastly, the results shed light into the high specific capacity of V6O13 and are likely to aid in the development of this material for use as a cathode for secondary lithium batteries.« less

  7. Tuning charge-discharge induced unit cell breathing in layer-structured cathode materials for lithium-ion batteries

    SciTech Connect

    Zhou, Yong-Ning; Ma, Jun; Hu, Enyuan; Yu, Xiqian; Gu, Lin; Nam, Kyung-Wan; Chen, Liquan; Wang, Zhaoxiang; Yang, Xiao-Qing

    2014-12-18

    For LiMO2 (M=Co, Ni, Mn) cathode materials, lattice parameters, a(b), contract during charge. Here we report such changes in opposite directions for lithium molybdenum trioxide (Li2MoO3). A ‘unit cell breathing’ mechanism is proposed based on crystal and electronic structural changes of transition metal oxides during charge-discharge. Metal–metal bonding is used to explain such ‘abnormal’ behaviour and a generalized hypothesis is developed. The expansion of the metal-metal bond becomes the controlling factor for a(b) evolution during charge, in contrast to the shrinking metal-oxygen bond as controlling factor in ‘normal’ materials. The cation mixing caused by migration of molybdenum ions at higher oxidation state provides the benefits of reducing the c expansion range in the early stage of charging and suppressing the structure collapse at high voltage charge. These results may open a new strategy for designing layered cathode materials for high energy density lithium-ion batteries.

  8. Electrodeposited Na2VOx[Fe(CN)6] films As a Cathode Material for Aqueous Na-Ion Batteries.

    PubMed

    Paulitsch, Bianca; Yun, Jeongsik; Bandarenka, Aliaksandr S

    2017-03-08

    The so-called Prussian blue analogues (PBAs) are spotlighted as promising cathode materials for aqueous Na-ion batteries regarding their good performance for the application in future large-scale energy storage systems. In this work, we demonstrate that one of the PBA representatives, namely Na2VOx[Fe(CN)6] thin films (VHCFs), is a promising cathode material for aqueous Na-ion batteries with very positive intercalation/deintercalation potentials, which might likely designate a new benchmark in the field. To maximize the material utilization, we have formed VHCF thin films on model current collectors from aqueous solutions. The resulting films demonstrated a very positive half-charge potential (ΔE1/2 ≈ 0.91 V vs Ag/AgCl reference electrode) in acidic media with a specific capacity of ∼80 mAh g(-1) recorded at high C-rates (30 C) in 1 M LiNO3, 3 M NaNO3 and 3 M KNO3 electrolytes in the presence of 3.6 M H2SO4. It is also shown that well-known solvation effects related to the nature of the alkali metal cations during intercalation and deintercalation are surprisingly not pronounced in the case of VHCFs.

  9. LiCaFeF6: A zero-strain cathode material for use in Li-ion batteries

    NASA Astrophysics Data System (ADS)

    de Biasi, Lea; Lieser, Georg; Dräger, Christoph; Indris, Sylvio; Rana, Jatinkumar; Schumacher, Gerhard; Mönig, Reiner; Ehrenberg, Helmut; Binder, Joachim R.; Geßwein, Holger

    2017-09-01

    A new zero-strain LiCaFeF6 cathode material for reversible insertion and extraction of lithium ions is presented. LiCaFeF6 is synthesized by a solid-state reaction and processed to a conductive electrode composite via high-energy ball-milling. In the first cycle, a discharge capacity of 112 mAh g-1 is achieved in the voltage range from 2.0 V to 4.5 V. The electrochemically active redox couple is Fe3+/Fe2+ as confirmed by Mössbauer spectroscopy and X-ray absorption spectroscopy. The compound has a trigonal colquiriite-type crystal structure (space group P 3 bar 1 c). By means of in situ and ex situ XRD as well as X-ray absorption fine structure spectroscopy a reversible response to Li uptake/release is found. For an uptake of 0.8 mol Li per formula unit only minimal changes occur in the lattice parameters causing a total change in unit cell volume of less than 0.5%. The spatial distribution of cations in the crystal structure as well as the linkage between their corresponding fluorine octahedra is responsible for this very small structural response. With its zero-strain behaviour this material is expected to exhibit only negligible mechanical degradation. It may be used as a cathode material in future lithium-ion batteries with strongly improved safety and cycle life.

  10. Phases of LiMn1.84V0.06Ti0.1O4 cathode material

    NASA Astrophysics Data System (ADS)

    Zainol, N. H.; Kamarulzaman, N.; Osman, Z.; Fadzil, A. F. M.; Yahya, N. F.

    2017-09-01

    In this work, LiMn1.84V0.06Ti0.1O4 was prepared via a combustion method using citric acid as a reductant. The precursor obtained was annealed at 700 °C for 24h in a furnace. The thermal profile of the precursor was obtained by simultaneous thermogravimetric analysis (STA). The observed material was characterized by X-ray Diffraction (XRD) and found to be pure and single-phase of cubic structure. The electrochemical performance of LiMn1.84V0.06Ti0.1O4 cathode material was studied by applying a constant current of 1.0 mA at a voltage range of 4.2 to 2.5 V. The specific capacity of LiMn1.84V0.06Ti0.1O4 cathode material at the 1st cycle shows the value of 95mAh/g which is less than the specific capacity of LiMn2O4, which is 117 mAh/g.

  11. Effect of temperature of Li2O-Al2O3-TiO2-P2O5 solid-state electrolyte coating process on the performance of LiNi0.5Mn1.5O4 cathode materials

    NASA Astrophysics Data System (ADS)

    Deng, Yu-Feng; Zhao, Shi-Xi; Xu, Ya-Hui; Nan, Ce-Wen

    2015-11-01

    Electrochemical performance of spinel LiNi0.5Mn1.5O4 (LNMO) at elevated temperature is improved by solid-state electrolyte Li2O-Al2O3-TiO2-P2O5 (LATP) coating. Crystallinity and thickness of coatings are controlled by adjusting the coating process at two different temperatures (550 and 650 °C). 2.0 wt.% LATP-modified LNMO cathode materials obtained at 650 °C exhibits remarkably promoted electrochemical performance compared to that of the pristine one in terms of cycling and rate ability at 55 °C. The enhanced performance of the surface-modified samples can be accounted for the suppressed side reactions between the cathode materials and electrolyte solution. What is more important is that LATP cannot only protect the active materials from electrolyte solution but also improve Li+ mobility. The higher crystallinity of glass-ceramic LATP coating layer with thinner thickness implies more unobstructed, stable and shorter diffusion path of Li+ transport. It is found that the coating process is in favor of the disordered to ordered phase transition, implying that the heating process of coating plays a role of anneal as well.

  12. Thermal and electrochemical properties of PEO-LiTFSI-Pyr14TFSI-based composite cathodes, incorporating 4 V-class cathode active materials

    NASA Astrophysics Data System (ADS)

    Wetjen, Morten; Kim, Guk-Tae; Joost, Mario; Appetecchi, Giovanni B.; Winter, Martin; Passerini, Stefano

    2014-01-01

    Poly(ethylene oxide)-lithium bis(trifluoromethanesulfonyl)imide N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PEO-LiTFSI-Pyr14TFSI)-based 4 V-class composite cathodes, incorporating either Li(Ni1/3Co1/3Mn1/3)O2 or Li(Ni0.8Co0.15Al0.05)O2 were prepared by a hot-pressing process and successively investigated in terms of their morphological, thermal, and electrochemical properties. Thereby, excellent mechanical and thermal properties could be demonstrated for all composite cathodes. The electrochemical performance of truly dry all-solid-state Li/P(EO)10LiTFSI-(Pyr14TFSI)2/composite cathode batteries at temperatures as low as 40 °C revealed high delivered capacities. However, in comparison with LiFePO4, the 4 V-class composite cathodes also indicated much lower capacity retention. In-depth investigations on the interfacial properties of Li(Ni0.8Co0.15Al0.05)O2 composite cathodes revealed a strong dependence on the anodic cut-off potential and the presence of current flow through the cell, whereby different degradation mechanisms could be characterized upon cycling, according to which the finite growth of a surface films at both electrode/polymer electrolyte interfaces inhibited continuous decomposition of the polymer electrolyte even at potentials as high as 4.3 V. Moreover, the presence of Pyr14TFSI in the 4 V-class composite cathodes sustainably reduced the cathode interfacial resistance and presumably diminished the corrosion of the aluminum current collector.

  13. Naphthalene Diimide Based n-Type Conjugated Polymers as Efficient Cathode Interfacial Materials for Polymer and Perovskite Solar Cells.

    PubMed

    Jia, Tao; Sun, Chen; Xu, Rongguo; Chen, Zhiming; Yin, Qingwu; Jin, Yaocheng; Yip, Hin-Lap; Huang, Fei; Cao, Yong

    2017-10-05

    A series of naphthalene diimide (NDI) based n-type conjugated polymers with amino-functionalized side groups and backbones were synthesized and used as cathode interlayers (CILs) in polymer and perovskite solar cells. Because of controllable amine side groups, all the resulting polymers exhibited distinct electronic properties such as oxidation potential of side chains, charge carrier mobilities, self-doping behaviors, and interfacial dipoles. The influences of the chemical variation of amine groups on the cathode interfacial effects were further investigated in both polymer and perovskite solar cells. We found that the decreased electron-donating property and enhanced steric hindrance of amine side groups substantially weaken the capacities of altering the work function of the cathode and trap passivation of the perovskite film, which induced ineffective interfacial modifications and declining device performance. Moreover, with further improvement of the backbone design through the incorporation of a rigid acetylene spacer, the resulting polymers substantially exhibited an enhanced electron-transporting property. Upon use as CILs, high power conversion efficiencies (PCEs) of 10.1% and 15.2% were, respectively, achieved in polymer and perovskite solar cells. Importantly, these newly developed n-type polymers were allowed to be processed over a broad thickness range of CILs in photovoltaic devices, and a prominent PCE of over 8% for polymer solar cells and 13.5% for perovskite solar cells can be achieved with the thick interlayers over 100 nm, which is beneficial for roll-to-roll coating processes. Our findings contribute toward a better understanding of the structure-performance relationship between CIL material design and solar cell performance, and provide important insights and guidelines for the design of high-performance n-type CIL materials for organic and perovskite optoelectronic devices.

  14. Preparation for CeO2/Nanographite Composite Materials and Electrochemical Degradation of Phenol by CeO2/Nanographite Cathodes.

    PubMed

    Yu, Li; Yu, Xiujuan; Sun, Tianyi; Wang, Na

    2015-07-01

    CeO2/nanographite (CeO2/nano-G) composite materials were got by chemical precipitation method with nanographite (nano-G) and cerous nitrate hexahydrate as raw materials. The microstructures of CeO2/nano-G composite materials were characterized by means of SEM, XRD, XPS and Raman. The cathodes were made by nano-G and CeO2/nano-G composite materials, respectively. The electrolysis phenol was conducted by the diaphragm cell prepared cathode and the Ti/RuO2 anode. The results indicated that the Cerium oxide is mainly in nanoscale spherical state, uniformly dispersed in the nanographite sheet surface, and there are two different oxidation states for elemental Ce, namely, Ce(III) and Ce(IV). In the diaphragm electrolysis system with the aeration conditions, the degradation rate of phenol reached 93.9% under 120 min's electrolysis. Ceria in the cathode materials might lead to an increase in the local oxygen concentration, which accelerated the two-electron reduction of O2 to hydrogen peroxide (H2O2). The removal efficiency of phenol by using the CeO2/nano-G composite cathode was better than that of the nano-G cathode.

  15. Dual-phase spinel MnCo2O4 and spinel MnCo2O4/nanocarbon hybrids for electrocatalytic oxygen reduction and evolution.

    PubMed

    Ge, Xiaoming; Liu, Yayuan; Goh, F W Thomas; Hor, T S Andy; Zong, Yun; Xiao, Peng; Zhang, Zheng; Lim, Suo Hon; Li, Bing; Wang, Xin; Liu, Zhaolin

    2014-08-13

    Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are essential reactions for energy-storage and -conversion devices relying on oxygen electrochemistry. High-performance, nonprecious metal-based hybrid catalysts are developed from postsynthesis integration of dual-phase spinel MnCo2O4 (dp-MnCo2O4) nanocrystals with nanocarbon materials, e.g., carbon nanotube (CNT) and nitrogen-doped reduced graphene oxide (N-rGO). The synergic covalent coupling between dp-MnCo2O4 and nanocarbons effectively enhances both the bifunctional ORR and OER activities of the spinel/nanocarbon hybrid catalysts. The dp-MnCo2O4/N-rGO hybrid catalysts exhibited comparable ORR activity and superior OER activity compared to commercial 30 wt % platinum supported on carbon black (Pt/C). An electrically rechargeable zinc-air battery using dp-MnCo2O4/CNT hybrid catalysts on the cathode was successfully operated for 64 discharge-charge cycles (or 768 h equivalent), significantly outperforming the Pt/C counterpart, which could only survive up to 108 h under similar conditions.

  16. Enhancement of electrochemical behavior of nanostructured LiFePO4/Carbon cathode material with excess Li

    NASA Astrophysics Data System (ADS)

    Bazzi, K.; Nazri, M.; Naik, V. M.; Garg, V. K.; Oliveira, A. C.; Vaishnava, P. P.; Nazri, G. A.; Naik, R.

    2016-02-01

    We have synthesized carbon coated LiFePO4 (C-LiFePO4) and C-Li1.05FePO4 with 5 mol% excess Li via sol-gel method using oleic acid as a source of carbon for enhancing electronic conductivity and reducing the average particle size. Although the phase purity of the crystalline samples was confirmed by x-ray diffraction (XRD), the 57Fe Mössbauer spectroscopy analyses show the presence of ferric impurity phases in both stoichiometric and non-stoichiometric C-LiFePO4 samples. Transmission electron microscopy measurements show nanosized C-LiFePO4 particles uniformly covered with carbon, with average particle size reduced from ∼100 nm to ∼50 nm when excess lithium is used. Electrochemical measurements indicate a lower charge transfer resistance and better electrochemical performance for C-Li1.05FePO4 compared to that of C-LiFePO4. The aim of this work is to systematically analyze the nature of impurities formed during synthesis of LiFePO4 cathode material, and their impact on electrochemical performance. The correlation between the morphology, charge transfer resistance, diffusion coefficient and electrochemical performance of C-LiFePO4 and C- Li1.05FePO4 cathode materials are discussed.

  17. Reduced graphene oxide as a stable and high-capacity cathode material for Na-ion batteries

    NASA Astrophysics Data System (ADS)

    Ali, Ghulam; Mehmood, Asad; Ha, Heung Yong; Kim, Jaehoon; Chung, Kyung Yoon

    2017-01-01

    We report the feasibility of using reduced graphene oxide (RGO) as a cost-effective and high performance cathode material for sodium-ion batteries (SIBs). Graphene oxide is synthesized by a modified Hummers’ method and reduced using a solid-state microwave irradiation method. The RGO electrode delivers an exceptionally stable discharge capacity of 240 mAh g-1 with a stable long cycling up to 1000 cycles. A discharge capacity of 134 mAh g-1 is obtained at a high current density of 600 mA g-1, and the electrode recovers a capacity of 230 mAh g-1 when the current density is reset to 15 mA g-1 after deep cycling, thus demonstrating the excellent stability of the electrode with sodium de/intercalation. The successful use of the RGO electrode demonstrated in this study is expected to facilitate the emergence of low-cost and sustainable carbon-based materials for SIB cathode applications.

  18. Iron-rich nanoparticle encapsulated, nitrogen doped porous carbon materials as efficient cathode electrocatalyst for microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Lu, Guolong; Zhu, Youlong; Lu, Lu; Xu, Kongliang; Wang, Heming; Jin, Yinghua; Jason Ren, Zhiyong; Liu, Zhenning; Zhang, Wei

    2016-05-01

    Developing efficient, readily available, and sustainable electrocatalysts for oxygen reduction reaction (ORR) in neutral medium is of great importance to practical applications of microbial fuel cells (MFCs). Herein, a porous nitrogen-doped carbon material with encapsulated Fe-based nanoparticles (Fe-Nx/C) has been developed and utilized as an efficient ORR catalyst in MFCs. The material was obtained through pyrolysis of a highly porous organic polymer containing iron(II) porphyrins. The characterizations of morphology, crystalline structure and elemental composition reveal that Fe-Nx/C consists of well-dispersed Fe-based nanoparticles coated by N-doped graphitic carbon layer. ORR catalytic performance of Fe-Nx/C has been evaluated through cyclic voltammetry and rotating ring-disk electrode measurements, and its application as a cathode electrocatalyst in an air-cathode single-chamber MFC has been investigated. Fe-Nx/C exhibits comparable or better performance in MFCs than 20% Pt/C, displaying higher cell voltage (601 mV vs. 591 mV), maximum power density (1227 mW m-2 vs. 1031 mW m-2) and Coulombic efficiency (50% vs. 31%). These findings indicate that Fe-Nx/C is more tolerant and durable than Pt/C in a system with bacteria metabolism and thus holds great potential for practical MFC applications.

  19. Reduced graphene oxide as a stable and high-capacity cathode material for Na-ion batteries

    PubMed Central

    Ali, Ghulam; Mehmood, Asad; Ha, Heung Yong; Kim, Jaehoon; Chung, Kyung Yoon

    2017-01-01

    We report the feasibility of using reduced graphene oxide (RGO) as a cost-effective and high performance cathode material for sodium-ion batteries (SIBs). Graphene oxide is synthesized by a modified Hummers’ method and reduced using a solid-state microwave irradiation method. The RGO electrode delivers an exceptionally stable discharge capacity of 240 mAh g−1 with a stable long cycling up to 1000 cycles. A discharge capacity of 134 mAh g−1 is obtained at a high current density of 600 mA g−1, and the electrode recovers a capacity of 230 mAh g−1 when the current density is reset to 15 mA g−1 after deep cycling, thus demonstrating the excellent stability of the electrode with sodium de/intercalation. The successful use of the RGO electrode demonstrated in this study is expected to facilitate the emergence of low-cost and sustainable carbon-based materials for SIB cathode applications. PMID:28098231

  20. High Rate, Long Lifespan LiV3 O8 Nanorods as a Cathode Material for Lithium-Ion Batteries.

    PubMed

    Chen, Zhongxue; Xu, Fei; Cao, Shunan; Li, Zhengfeng; Yang, Hanxi; Ai, Xinping; Cao, Yuliang

    2017-05-01

    LiV3 O8 nanorods with controlled size are successfully synthesized using a nonionic triblock surfactant Pluronic-F127 as the structure directing agent. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy techniques are used to characterize the samples. It is observed that the nanorods with a length of 4-8 µm and diameter of 0.5-1.0 µm distribute uniformly. The resultant LiV3 O8 nanorods show much better performance as cathode materials in lithium-ion batteries than normal LiV3 O8 nanoparticles, which is associated with the their unique micro-nano-like structure that can not only facilitate fast lithium ion transport, but also withstand erosion from electrolytes. The high discharge capacity (292.0 mAh g(-1) at 100 mA g(-1) ), high rate capability (138.4 mAh g(-1) at 6.4 A g(-1) ), and long lifespan (capacity retention of 80.5% after 500 cycles) suggest the potential use of LiV3 O8 nanorods as alternative cathode materials for high-power and long-life lithium ion batteries. In particular, the synthetic strategy may open new routes toward the facile fabrication of nanostructured vanadium-based compounds for energy storage applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Advanced cathode materials for polymer electrolyte fuel cells based on pt/ metal oxides: from model electrodes to catalyst systems.

    PubMed

    Fabbri, Emiliana; Pătru, Alexandra; Rabis, Annett; Kötz, Rüdiger; Schmidt, Thomas J

    2014-01-01

    The development of stable catalyst systems for application at the cathode side of polymer electrolyte fuel cells (PEFCs) requires the substitution of the state-of-the-art carbon supports with materials showing high corrosion resistance in a strongly oxidizing environment. Metal oxides in their highest oxidation state can represent viable support materials for the next generation PEFC cathodes. In the present work a multilevel approach has been adopted to investigate the kinetics and the activity of Pt nanoparticles supported on SnO2-based metal oxides. Particularly, model electrodes made of SnO2 thin films supporting Pt nanoparticles, and porous catalyst systems made of Pt nanoparticles supported on Sb-doped SnO2 high surface area powders have been investigated. The present results indicate that SnO2-based supports do not modify the oxygen reduction reaction mechanism on the Pt nanoparticle surface, but rather lead to catalysts with enhanced specific activity compared to Pt/carbon systems. Different reasons for the enhancement in the specific activity are considered and discussed.

  2. The influence of reduced graphene oxide on electrical conductivity of LiFePO4-based composite as cathode material

    NASA Astrophysics Data System (ADS)

    Arifin, Muhammad; Aimon, Akfiny Hasdi; Winata, Toto; Abdullah, Mikrajuddin; Iskandar, Ferry

    2016-02-01

    LiFePO4 is fascinating cathode active materials for Li-ion batteries application because of their high electrochemical performance such as a stable voltage at 3.45 V and high specific capacity at 170 mAh.g-1. However, their low intrinsic electronic conductivity and low ionic diffusion are still the hindrance for their further application on Li-ion batteries. Therefore, the efforts to improve their conductivity are very important to elevate their prospecting application as cathode materials. Herein, we reported preparation of additional of reduced Graphene Oxide (rGO) into LiFePO4-based composite via hydrothermal method and the influence of rGO on electrical conductivity of LiFePO4-based composite by varying mass of rGO in composition. Vibration of LiFePO4-based composite was detected on Fourier Transform Infrared Spectroscopy (FTIR) spectra, while single phase of LiFePO4 nanocrystal was observed on X-Ray Diffraction (XRD) pattern, it furthermore, Scanning Electron Microscopy (SEM) images showed that rGO was distributed around LiFePO4-based composite. Finally, the 4-point probe measurement result confirmed that the optimum electrical conductivity is in additional 2 wt% rGO for range 1 to 2 wt% rGO.

  3. Electrochemical properties of large-sized pouch-type lithium ion batteries with bio-inspired organic cathode materials

    NASA Astrophysics Data System (ADS)

    Yeo, Jae-Seong; Yoo, Eun-Ji; Ha, Sang-Hyeon; Cheong, Dong-Ik; Cho, Sung-Baek

    2016-05-01

    To investigate the feasibility of scaling up bio-inspired organic materials as cathode materials in lithium ion batteries, large-sized pouch cells are successfully prepared via tape casting using lumichrome with an alloxazine structure and aqueous styrene butadiene rubber-carboxymethyl cellulose (SBR-CMC) binders. A battery module with a two-in-series, six-in-parallel (2S6P) configuration is also successfully fabricated and is able to power blue LEDs (850 mW). Lumichrome shows no structural changes during the fabrication processes used to produce the positive electrode. The large-sized pouch cells show two sets of cathodic and anodic peaks with average potentials of 2.58 V and 2.26 V vs. Li/Li+, respectively. The initial discharge capacities are 142 mAh g-1 and 148 mAh g-1 for ethylene carbonate-dimethyl carbonate (EC-DMC) and tetraethylene glycol dimethyl ether (TEGDME) electrolytes, respectively, similar to that of a coin cell (149 mAh g-1). The EC-DMC-injected pouch cells exhibit higher rate performance and cyclability than the TEGDME-injected ones. The TEGDME electrolyte is not suitable for lithium metal anodes because of electrolyte decomposition and subsequent cell swelling.

  4. Recovery of valuable metals from cathodic active material of spent lithium ion batteries: Leaching and kinetic aspects.

    PubMed

    Meshram, Pratima; Pandey, B D; Mankhand, T R

    2015-11-01

    This work is focussed on the processing of cathodic active material of spent lithium ion batteries (LIBs) to ensure resource recovery and minimize environmental degradation. The sulfuric acid leaching of metals was carried out for the recovery of all the valuable metals including nickel and manganese along with the frequently targeted metals like lithium and cobalt. The process parameters such as acid concentration, pulp density, time and temperature for the leaching of metals from the cathode powder containing 35.8% Co, 6.5% Li, 11.6% Mn and 10.06% Ni, were optimized. Results show the optimized leach recovery of 93.4% Li, 66.2% Co, 96.3% Ni and 50.2% Mn when the material was leached in 1M H2SO4 at 368 K and 50 g/L pulp density for 240 min. The need of a reductant for improved recovery of cobalt and manganese has been explained by the thermodynamic analysis (Eh-pH diagram) for these metals. Leaching of the valuable metals was found to follow the logarithmic rate law controlled by surface layer diffusion of the lixiviant reacting with the particles. The mode of leaching of the metals from the spent LIBs was further examined by chemical analysis of the samples at various stage of processing which was further corroborated by characterizing the untreated sample and the leach residues by XRD phase identification and the SEM-EDS studies.

  5. Hollow spherical carbonized polypyrrole/sulfur composite cathode materials for lithium/sulfur cells with long cycle life

    NASA Astrophysics Data System (ADS)

    Wang, Zhongbao; Zhang, Shichao; Zhang, Lan; Lin, Ruoxu; Wu, Xiaomeng; Fang, Hua; Ren, Yanbiao

    2014-02-01

    Hollow carbonized polypyrrole (PPy) spheres are synthesized using poly(methyl methacrylate-ethyl acrylate-acrylic acid) latex spheres as sacrificial templates. The hollow spherical carbonized PPy/sulfur composite cathode materials are prepared by heating the mixture of hollow carbonized PPy spheres and element sulfur at 155 °C for 24 h. Scanning electron microscope (SEM) and transmission electron microscope (TEM) observations show the hollow structures of the carbonized PPy spheres and the homogeneous distribution of sulfur on the carbonized PPy shells. The hollow spherical carbonized PPy/sulfur composite with 60.9 wt.% S shows high specific capacity and excellent cycling stability when used as the cathode materials in lithium/sulfur cells, whose initial specific discharge capacity reaches as high as 1320 mA h g-1 and the reversible discharge capacity retains 758 mA h g-1 after 400 cycles at 0.2C. The excellent electrochemical properties benefit from the hollow structures and the flexible shells of the carbonized PPy spheres.

  6. Transmission electron microscopy (TEM) investigations of Mn-oxide rich cathodic material from spent disposable alkaline batteries

    SciTech Connect

    Krekeler, Mark P.S.

    2008-11-15

    Transmission electron microscopy (TEM) techniques were used to investigate the spent cathodic material of a single common brand of disposable alkaline batteries. Mn-oxide particles are anhedral and irregular in shape and compose an estimated 99-95% of the <10 {mu}m size fraction of sample material. Diameters of particles vary widely and typically are between 50 nm and 3 {mu}m; however, most particles are approximately 200-400 nm in diameter. Chemical composition varies for Mn-oxide particles with concentrations being SiO{sub 2} (0.00-1.52 wt%), TiO{sub 2} (0.49-4.58 wt%), MnO (65.85-92.06 wt%), ZnO (1.00-7.53 wt%), K{sub 2}O (4.97-20.48 wt%) and SO{sub 3} (0.43-2.21 wt%). Discrete prismatic zinc crystals occur and vary from a maximum of approximately 0.8 {mu}m long x 0.15 {mu}m wide, to 100 nm long x 20 nm wide. Titanium metal was also observed in samples and composes approximately 0.25-1.0% of the <10 {mu}m size fraction of sample material. Results of this study suggest that battery components may be recycled in some special applications. Examples are low energy-low material requirement products such as paint pigments and Zn nanoparticles. This investigation provides detailed constraints on the nature of spent cathodic materials to improve existing recycling methods and develop new technologies.

  7. Unraveling the Complex Delithiation Mechanisms of Olivine- Type Cathode Materials, LiFexCo1-xPO4

    SciTech Connect

    Strobridge, Fiona C.; Liu, Hao; Leskes, Michal; Borkiewicz, Olaf J.; Wiaderek, Kamila M.; Chupas, Peter J.; Chapman, Karena W.; Grey, Clare P.

    2016-06-14

    The delithiation mechanisms occurring within the olivine-type class of cathode materials for Li-ion batteries have received considerable attention owing to the good capacity retention at high rates for LiFePO4. A comprehensive mechanistic study of the (de)lithiation reactions that occur when the substituted olivine-type cathode materials LiFexCo1-xPO4 (x = 0, 0.05, 0.125, 0.25, 0.5, 0.75, 0.875, 0.95 and 1) are electrochemically cycled is reported here, using in situ X-ray diffraction (XRD) data. On the first charge, two intermediate phases are observed and identified: Li1-x(Fe3+)x(Co2+)1- xPO4 for 0 < x < 1 (i.e. after oxidation of Fe2+ => Fe3+) and Li2/3FexCo1-xPO4 for 0 ≤ x ≤ 0.5 (i.e. the Co-majority materials). For the Fe-rich materials, we study how nonequilibrium, single-phase mechanisms that occur discretely in single particles, as observed for LiFePO4 at high rates, is affected by Co substitution. In the Co-majority materials, a two-phase mechanism with a coherent interface is observed, as was seen in LiCoPO4, and we discuss how it is manifested in the XRD patterns. We then compare the nonequilibrium, single-phase mechanism with the bulk single-phase and the coherent interface two-phase mechanisms. Despite the apparent differences between these mechanisms, we discuss how they are related and interconverted as a function of Fe/Co substitution and the potential implications for the electrochemistry of this system.

  8. Transparent Spinel Ceramic

    DTIC Science & Technology

    2009-01-01

    2009 NRL REVIEW 215 OPTICAL SCIENCES Transparent Spinel Ceramic J.S. Sanghera, G. Villalobos , W. Kim, S. Bayya, and I.D. Aggarwal Optical Sciences...Sponsored by NRL and ONR] Reference 1 G. Villalobos , J.S. Sanghera, S.B. Bayya, and I.D. Aggarwal, “Fluoride Salt Coated Magnesium Aluminate,” U.S. Patent 7,211,325, May 1, 2007.

  9. Electrochemical performance of La2O3/Li2O/TiO2 nano-particle coated cathode material LiFePO4.

    PubMed

    Wang, Hong; Yang, Chi; Liu, Shu-Xin

    2014-09-01

    Cathode material, LiFePO4 was modified by coating with a thin layer of La2O3/Li2O/TiO2 nano-particles for improving its performance for lithium ion batteries. The morphology and structure of the modified cathode material were characterized by powder X-ray diffraction, scanning electron microcopy and AES. The performance of the battery with the modified cathode material, including cycling stability, C-rate discharge was examined. The results show that the battery composed of the coated cathode materials can discharge at a large current density and show stable cycling performance in the range from 2.5 to 4.0 V. The rate of Li ion diffusion increases in the battery with the La2O3/Li2O/TiO2-coated LiFePO4 as a cathode and the coating layer may acts as a faster ion conductor (La(2/3-x)Li(3x)TiO3).

  10. Nitrogen--sulfur--carbon nanocomposites and their application as cathode materials in lithium--sulfur batteries

    DOEpatents

    Dai, Sheng; Sun, Xiao-Guang; Guo, Bingkun; Wang, Xiqing; Mayes, Richard T.; Ben, Teng; Qiu, Shilun

    2016-09-27

    The invention is directed in a first aspect to electron-conducting porous compositions comprising an organic polymer matrix doped with nitrogen atoms and having elemental sulfur dispersed therein, particularly such compositions having an ordered framework structure. The invention is also directed to composites of such S/N-doped electron-conducting porous aromatic framework (PAF) compositions, or composites of an S/N-doped mesoporous carbon composition, which includes the S/N-doped composition in admixture with a binder, and optionally, conductive carbon. The invention is further directed to cathodes for a lithium-sulfur battery in which such composites are incorporated.

  11. The structural and chemical origin of the oxygen redox activity in layered and cation-disordered Li-excess cathode materials.

    PubMed

    Seo, Dong-Hwa; Lee, Jinhyuk; Urban, Alexander; Malik, Rahul; Kang, ShinYoung; Ceder, Gerbrand

    2016-07-01

    Lithium-ion batteries are now reaching the energy density limits set by their electrode materials, requiring new paradigms for Li(+) and electron hosting in solid-state electrodes. Reversible oxygen redox in the solid state in particular has the potential to enable high energy density as it can deliver excess capacity beyond the theoretical transition-metal redox-capacity at a high voltage. Nevertheless, the structural and chemical origin of the process is not understood, preventing the rational design of better cathode materials. Here, we demonstrate how very specific local Li-excess environments around oxygen atoms necessarily lead to labile oxygen electrons that can be more easily extracted and participate in the practical capacity of cathodes. The identification of the local structural components that create oxygen redox sets a new direction for the design of high-energy-density cathode materials.

  12. Solid state cathode materials for secondary magnesium-ion batteries that are compatible with magnesium metal anodes in water-free electrolyte

    NASA Astrophysics Data System (ADS)

    Crowe, Adam J.; Bartlett, Bart M.

    2016-10-01

    With high elemental abundance, large volumetric capacity, and dendrite-free metal deposition, magnesium metal anodes offer promise in beyond-lithium-ion batteries. However, the increased charge density associated with the divalent magnesium-ion (Mg2+), relative to lithium-ion (Li+) hinders the ion-insertion and extraction processes within many materials and structures known for lithium-ion cathodes. As a result, many recent investigations incorporate known amounts of water within the electrolyte to provide temporary solvation of the Mg2+, improving diffusion kinetics. Unfortunately with the addition of water, compatibility with magnesium metal anodes disappears due to forming an ion-insulating passivating layer. In this short review, recent advances in solid state cathode materials for rechargeable magnesium-ion batteries are highlighted, with a focus on cathode materials that do not require water contaminated electrolyte solutions for ion insertion and extraction processes.

  13. Porous LiFePO4/C microspheres as high-power cathode materials for lithium ion batteries.

    PubMed

    Sun, Bing; Wang, Ying; Wang, Bei; Kim, Hyun-Soo; Kim, Woo-Seong; Wang, Guoxiu

    2013-05-01

    Porous LiFePO4/C microspheres were synthesized by a novel hydrothermal reaction combined with high-temperature calcinations. The morphology of the prepared material was investigated by field-emission scanning electron microscopy. Porous microspheres with diameters around 1-3 microm were obtained, which consisting of primary LiFePO4 nanoparticles. The electrochemical performances of the as-prepared LiFePO4 microspheres were evaluated by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge cycling. The carbon coated LiFePO4 microspheres showed lower polarization, higher rate capability, and better cycling stability than that of pristine LiFePO4 microspheres, indicating the potential application as the cathode material for high-power lithium ion batteries.

  14. Large-Scale Production of V6O13 Cathode Materials Assisted by Thermal Gravimetric Analysis-Infrared Spectroscopy Technology.

    PubMed

    Liang, Han-Pu; Du, Jian; Jones, Timothy G J; Lawrence, Nathan S; Meredith, Andrew W

    2016-10-05

    The kilogram-scale fabrication of V6O13 cathode materials has been notably assisted by in situ thermal gravimetric analysis (TGA)-infrared spectroscopy (IR) technology. This technology successfully identified a residue of ammonium metavanadate in commercial V6O13, which is consistent with the X-ray photoelectron spectroscopy result. Samples of V6O13 materials have been fabricated and characterized by TGA-IR, scanning electron microscopy, and X-ray diffraction. The initial testing results at 125 °C have shown that test cells containing the sample prepared at 500 °C show up to a 10% increase in the initial specific capacity in comparison with commercial V6O13.

  15. Characterization of (Mg, La) Substituted Ni-Zn Spinel Ferrite

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Wei, S. C.; Wang, Y. J.; Tian, H. L.; Tong, H.; Xu, B. S.

    Spinel structure of (Mg, La) substituted spinel Ni-Zn ferrite has been synthesized by sol-gel auto combustion method. The ferrite exhibits a single-spinel structure. The ferrite is studied as a microwave absorbing material. The microwave measurements are carried out by a vector network analyzer. The reflection loss of the ferrite is calculated as a single-layer absorber. The results indicate that the ferrite annealed at 850°C has great potential for application in electromagnetic wave attenuation.

  16. Synthesis of a LiFePO4/C cathode material by using a high-energy nano mill

    NASA Astrophysics Data System (ADS)

    Islam, Mobinul; Yoon, Man-Soon; Ur, Soon-Chul

    2015-07-01

    Olivine lithium iron phosphate (LiFePO4) is a promising cathode material for Li-ion battery. A temperature around 700 - 800 ℃ is generally required to prepare LiFePO4 powder with good crystallinity. The LiFePO4 materials are synthesized via a solid-state method by using a highenergy nano mill (HENM). The conventional ball-milling process is also conducted for the same material for a comparative study. The effect of the precursor's mixing processes on the synthesis temperature of LiFePO4 is investigated in this study. The required reaction temperature of LiFePO4 is 432 ℃ for the HENM process and 480 ℃ for the ball-mill process as found from the differential scanning calorimetry (DSC) results. The HENM process improves the reaction activity and the homogeneity of the materials used throughout process and lowers the reaction temperature as compared with the conventional ball-mill process. The milled powders are characterized by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The sample synthesized by using the HENM process exhibits a discharge capacity of 136 mAhg -1 at 0.1 C rate. The results in this study indicate that the HENM process is a substantial and promising process for LiFePO4 cathode preparation owing to its short fabrication time and ability to improve the reaction condition. A HENM can be used to promote formation of LiFePO4 at lower temperatures.

  17. Investigating the reversibility of structural modifications of LixNiyMnzCo1-y-zO₂ cathode materials during initial charge/discharge, at multiple length scales

    DOE PAGES

    Hwang, Sooyeon; Bak, Seong -Min; Kim, Seung Min; ...

    2015-08-11

    In this work, we investigate the structural modifications occurring at the bulk, subsurface, and surface scales of LixNiyMnzCo1-y-zO₂ (NMC; y, z = 0.8, 0.1 and 0.4, 0.3, respectively) cathode materials during the initial charge/discharge. Various analytical tools, such as X-ray diffraction, selected-area electron diffraction, electron energy-loss spectroscopy, and high-resolution electron microscopy, are used to examine the structural properties of the NMC cathode materials at the three different scales. Cut-off voltages of 4.3 and 4.8 V are applied during the electrochemical tests as the normal and extreme conditions, respectively. The high-Ni-content NMC cathode materials exhibit unusual behaviors, which is deviate frommore » the general redox reactions during the charge or discharge. The transition metal (TM) ions in the high-Ni-content NMC cathode materials, which are mostly Ni ions, are reduced at 4.8 V, even though TMs are usually oxidized to maintain charge neutrality upon the removal of Li. It was found that any changes in the crystallographic and electronic structures are mostly reversible down to the sub-surface scale, despite the unexpected reduction of Ni ions. However, after the discharge, traces of the phase transitions remain at the edges of the NMC cathode materials at the scale of a few nanometers (i.e., surface scale). This study demonstrates that the structural modifications in NMC cathode materials are induced by charge as well as discharge at multiple length scales. These changes are nearly reversible after the first cycle, except at the edges of the samples, which should be avoided because these highly localized changes can initiate battery degradation.« less

  18. Compositional variations in lunar spinels.

    NASA Technical Reports Server (NTRS)

    Haggerty, S. E.

    1971-01-01

    Electron probe data for spinels from Apollo 11, 12, and 14 are presented and analyzed. A modified Johnstone spinel prism showing the data distribution is given. Three projections of this prism are then presented which illustrate the variations of simple ratios that are present in the prism and permit three different perspectives of the data. The results are summarized as fO2 isobars on the spinel prism.

  19. Compositional variations in lunar spinels.

    NASA Technical Reports Server (NTRS)

    Haggerty, S. E.

    1971-01-01

    Electron probe data for spinels from Apollo 11, 12, and 14 are presented and analyzed. A modified Johnstone spinel prism showing the data distribution is given. Three projections of this prism are then presented which illustrate the variations of simple ratios that are present in the prism and permit three different perspectives of the data. The results are summarized as fO2 isobars on the spinel prism.

  20. Dopants and defects in conductive oxide spinels

    NASA Astrophysics Data System (ADS)

    Zakutayev, Andriy; Perkins, John; Parilla, Phillip; Paudel, Tula; Lany, Staphan; Ginely, David; Zunger, Alex

    2011-03-01

    We will discuss the effects of extrinsic and intrinsic imperfections (dopants and defects) in a group of conductive oxide materials related to Co3O4. Co3O4 is a spinel with Co2+ and Co3+ on tetrahedral and octahedral sites, respectively. Doping of Co3O4 with Zn and Ni represent two limiting cases: Zn2+ ions have a preference to occupy tetrahedral (Co2+) sites and are predicted to be unable to dope effectively; Ni2+ ions have a preference to occupy octahedral (Co3+) sites, so these atoms are expected to be efficient dopants. We found that substitution of Co3O4 spinel with up to 33 percent of Zn and Ni results in formation of ZnCo2O4 normal spinel and NiCo2O4 inverse spinel, and causes 100-fold and 1000-fold increases in conductivity, respectively, matching the predicted trend. Increase in Zn and Ni concentraion up to 40 percent cause phase separation of ZnO and NiO and leveling out of the conductivity. The conductivity decreases sharply above 50-60 percent Zn and Ni substitution level. Small differences with the theoretical predictions may be explained by non-equilibrium character of the thin film deposition process. This work was supported by the ``Center for Inverse Design'' EFRC of the Department of Energy.

  1. Nonaqueous lithium-ion capacitors with high energy densities using trigol-reduced graphene oxide nanosheets as cathode-active material.

    PubMed

    Aravindan, Vanchiappan; Mhamane, Dattakumar; Ling, Wong Chui; Ogale, Satishchandra; Madhavi, Srinivasan

    2013-12-01

    One HEC of a material: The use of trigol-reduced graphene oxide nanosheets as cathode material in hybrid lithium-ion electrochemical capacitors (Li-HECs) results in an energy density of 45 Wh kg(-1) ; much enhanced when compared to similar devices. The mass loading of the active materials is optimized, and the devices show good cycling performance. Li-HECs employing these materials outperform other supercapacitors, making them attractive for use in power sources.

  2. The synergistic effect of inert oxide and metal fluoride dual coatings on advanced cathode materials for lithium ion battery applications.

    PubMed

    Park, Kwangjin; Lee, Byoung-Sun; Park, Jun-Ho; Hong, Suk-Gi

    2016-06-21

    The effect of Al2O3/LiF dual coatings on the electrochemical performance of over-lithiated layered oxide (OLO) has been investigated. A uniform coating of Al2O3 and LiF is obtained on the surface of the layered pristine material. The OLO with a dual Al2O3/LiF coating with a ratio of 1 : 1.5 exhibits excellent electrochemical performance. An initial discharge capacity of 265.66 mA h g(-1) is obtained at a C-rate of 0.1C. This capacity is approximately 15 mA h g(-1) higher than that of pristine OLO. The capacity retention (92.8% at the 50th cycle) is also comparable to that of pristine OLO (91.4% at the 50th cycle). Coating the cathode with a dual layer comprising Al2O3 and LiF leads to improved charging and discharging kinetics, and prevents direct contact between the cathode and the electrolyte.

  3. The roles of oxygen non-stoichiometry on the electrochemical properties of oxide-based cathode materials

    SciTech Connect

    Zheng, Jianming; Xiao, Jie; Zhang, Ji-Guang

    2016-10-01

    The capacity degradation mechanism in lithium nickel-manganese-cobalt oxide (NMC) cathodes (LiNi1/3Mn1/3Co1/3O2 (NMC333) and LiNi0.4Mn0.4Co0.2O2 (NMC442)) during high-voltage (cut-off of 4.8 V) operation has been investigated. In contrast to NMC442, NMC333 exhibits rapid structural changes including severe micro-crack formation and phase transformation from a layered to a disordered rock-salt structure, as well as interfacial degradation during high-voltage cycling, leading to a rapid increase of the electrode resistance and fast capacity decline. The fundamental reason behind the poor structural and interfacial stability of NMC333 was found to be correlated to its high Co content and the significant overlap between the Co3+/4+ t2g and O2- 2p bands, resulting in oxygen removal and consequent structural changes at high voltages. In addition, oxidation of the electrolyte solvents by the extracted oxygen species generates acidic species, which then attack the electrode surface and form highly resistive LiF. These findings highlight that both the structural and interfacial stability should be taken into account when tailoring cathode materials for high voltage battery systems.

  4. Designing Air-Stable O3-Type Cathode Materials by Combined Structure Modulation for Na-Ion Batteries

    DOE PAGES

    Yao, Hu-Rong; Wang, Peng-Fei; Gong, Yue; ...

    2017-06-09

    As promising high-capacity cathode materials for Na-ion batteries, O3-type Na-based metal oxides always suffer from their poor air stability originating from the spontaneous extraction of Na and oxidation of transition metals when exposed to air. Here, a combined structure modulation is proposed to tackle concurrently the two handicaps via reducing Na layers spacing and simultaneously increasing valence state of transition metals. Guided by density functional theory calculations, we demonstrate such a modulation can be subtly realized through cosubstitution of one kind of heteroatom with comparable electronegativity and another one with substantially different Fermi level, by adjusting the structure of NaNi0.5Mn0.5O2more » via Cu/Ti codoping. The as-obtained NaNi0.45Cu0.05Mn0.4Ti0.1O2 exhibits an increase of 20 times in stable air-exposure period and 9 times in capacity retention after 500 cycles, and even retains its structure and capacity after being soaked in water. In such a simple and effective structure modulation reveals a new avenue for high-performance O3-type cathodes and pushes the large-scale industrialization of Na-ion batteries a decisive step forward.« less

  5. A preliminary investigation into the new class of lithium intercalating LiNiSiO4 cathode material

    NASA Astrophysics Data System (ADS)

    Jayaprakash, N.; Kalaiselvi, N.; Periasamy, P.

    2008-01-01

    A unique attempt to exploit silicate chemistry for a possible enhancement of the electrochemical properties of a lithium ion system via exploration of the novel category lithium intercalating LiNiSiO4 cathode has been made through the present study. A novel citric acid assisted modified sol-gel method (CAM sol-gel) has been adopted to synthesize the title compound with a formation temperature positioned well below 500 °C, as derived from thermal studies. A powder x-ray diffraction (PXRD) pattern evidenced the absence of undesirable peaks and confirmed the formation of a hexagonal lattice structure with enhanced crystallinity and phase purity, and the presence of uniformly distributed particles of ~200 nm size with well defined grain boundaries is obvious from the scanning electron microscopy (SEM) image of LiNiSiO4 material. Further, magic angle spinning (MAS) 7Li nuclear magnetic resonance (NMR) results from LiNiSiO4 confirmed the presence of a layered type of crystal arrangement. A cyclic voltammetry (CV) study performed on a LiNiSiO4 cathode revealed an excellent reversibility without any change in the peak position upon extended cycling, thus substantiating the structural stability upon progressive cycling.

  6. Cobalt based layered perovskites as cathode material for intermediate temperature Solid Oxide Fuel Cells: A brief review

    NASA Astrophysics Data System (ADS)

    Pelosato, Renato; Cordaro, Giulio; Stucchi, Davide; Cristiani, Cinzia; Dotelli, Giovanni

    2015-12-01

    Nowadays, the cathode is the most studied component in Intermediate Temperature-Solid Oxide Fuel Cells (IT-SOFCs). Decreasing SOFCs operating temperature implies slow oxygen reduction kinetics and large polarization losses. Double perovskites with general formula REBaCo2O5+δ are promising mixed ionic-electronic conductors, offering a remarkable enhancement of the oxygen diffusivity and surface exchange respect to disordered perovskites. In this review, more than 250 compositions investigated in the literature were analyzed. The evaluation was performed in terms of electrical conductivity, Area Specific Resistance (ASR), chemical compatibility with electrolytes and Thermal Expansion Coefficient (TEC). The most promising materials have been identified as those bearing the mid-sized rare earths (Pr, Nd, Sm, Gd). Doping strategies have been analyzed: Sr doping on A site promotes higher electrical conductivity, but worsen ASR and TECs; B-site doping (Fe, Ni, Mn) helps lowering TECs, but is detrimental for the electrochemical properties. A promising boost of the electrochemical activity is obtained by simply introducing a slight Ba under-stoichiometry. Still, the high sensitivity of the electrochemical properties against slight changes in the stoichiometry hamper a conclusive comparison of all the investigated compounds. Opportunities for an improvement of double perovskite cathodes performance is tentatively foreseen in combining together the diverse effective doping strategies.

  7. A high-voltage honeycomb-layered Na4NiTeO6 as cathode material for Na-ion batteries

    NASA Astrophysics Data System (ADS)

    Yang, Ze; Jiang, Yan; Deng, Liangzi; Wang, Ting; Chen, Shuo; Huang, Yunhui

    2017-08-01

    We report a high-voltage Na4NiTeO6 cathode material for Na-ion batteries. It delivers 111 mAh g-1 at 0.1 C with 87% contribution from the inductive effect at the voltage beyond 3.5 V. With addition of fluoroethylene carbonate, stable fluorine-containing solid electrode interface is formed, which significantly improve its cyclic performance. Our results provide insights into designing sodium layered cathode materials with high voltage, which will benefit for the development of high energy Na-ion batteries.

  8. FePO 4 nanoparticles supported on mesoporous SBA-15: Interesting cathode materials for Li-ion cells

    NASA Astrophysics Data System (ADS)

    Gerbaldi, C.; Meligrana, G.; Bodoardo, S.; Tuel, A.; Penazzi, N.

    Exploiting the properties of stability, low cost and low toxicity of iron phosphates, we have tried to enhance the performance of FePO 4 as cathode material for Li-ion cells. We adopted the strategy of obtaining FePO 4, via a typical preparation, onto the channels of an ordered mesoporous SBA-15 silica, a low cost mesoporous material commonly used in industry, which possesses larger pores, thicker walls and higher thermal stability as compared with other mesoporous silicas like MCM-41. Characterizations with ICP-AES, XRPD, BET and HRTEM suggest that the supported iron phosphate species, with loading amounts as high as 30 wt%, are located and dispersed in the mesopores of SBA-15. Iron phosphate can be reduced/oxidized more readily than the unsupported iron phosphate at room temperature, and in fact, cycling at C/10, the supported phosphate shows a utilization of 70% with respect to a value of 30% for the unsupported solid. The result is interesting from the scientific viewpoint but not suitable for application at the moment. Indeed, the amount of active material does not exceed 30% of the electrode mass and the total electrode capacity, though the active material is very efficient, is largely insufficient. Researches are being developed trying to increase the performances of the materials and also to eliminate the support after the dispersion of the active material.

  9. Turning Waste Chemicals into Wealth-A New Approach To Synthesize Efficient Cathode Material for an Li-O2 Battery.

    PubMed

    Yao, Ying; Wu, Feng

    2017-09-05

    An Li-O2 battery requires the oxygen-breathing cathode to be highly electronically conductive, rapidly oxygen diffusive, structurally stable, and often times electrocatalytically active. Catalyst-decorated porous carbonaceous materials are the chosen air cathode in this regard. Alternatively, biomass-derived carbonaceous materials possess great ability to remove heavy and toxic metal ions from waste, forming a metal-adsorbed porous carbonaceous material. The similar structure between the air cathode and the metal-adsorbed biomass-derived carbon nicely bridges these two irrelevant areas. In this study, we investigated the electrochemical activity of a biochar material Ag-ESB directly synthesized from ethanol sludge residue in a rechargeable aprotic Li-O2 battery. Ag ions were adsorbed from sewage and became Ag nanoparticles with uniform coverage on the biochar surface. The as-prepared material exhibits good electrochemical behavior in battery testing, especially toward the battery efficiency and cyclability. This study provides the possibility of synthetically efficient cathode material by reusing "waste" such as biofuel sludge residue. It is an economically and environmentally friendly approach both for an energy-storage system and for waste recycling.

  10. Targeted partial surface modification with nano-SiO2@Li2CoPO4F as high-voltage cathode material for LIBs

    NASA Astrophysics Data System (ADS)

    Chang, Caiyun; Huang, Zhipeng; Tian, Runsai; Jiang, Xinyu; Li, Chunsheng; Feng, Jijun

    2017-10-01

    Tuning whole/partial surface modification on cathode material with oxide material is a sought-after method to enhance the electrochemical performance in power storage field. Herein, nano-SiO2 targeted partial surface modified high voltage cathode material Li2CoPO4F has been successfully fabricated via a facile self-assembly process in silica dispersion at ambient temperature. With the aid of polar -OH groups attracted on the surface of SiO2 micelles, the nano-SiO2 preferentially nestle up along the borders and boundaries of Li2CoPO4F particles, where protection should be deployed with emphasis against the undesirable interactions between materials and electrolytes. Compared with pristine Li2CoPO4F, the SiO2 selectively modified Li2CoPO4F cathode materials, especially LCPF-3S, exhibit desirable electrochemical performances with higher discharge capacity, more outstanding cycle stability and favorable rate capability without any additional carbon involved. The greatly enhanced electrochemical properties can be attributed to the improved lithium-ion diffusion kinetics and structure tolerance during repeated lithiation/delithiation process. Such findings reveal a great potential of nano-SiO2 modified Li2CoPO4F as high energy cathode material for lithium ion batteries.

  11. Y-doped Li8ZrO6: A Li-Ion Battery Cathode Material with High Capacity.

    PubMed

    Huang, Shuping; Wilson, Benjamin E; Wang, Bo; Fang, Yuan; Buffington, Keegan; Stein, Andreas; Truhlar, Donald G

    2015-09-02

    We study--experimentally and theoretically--the energetics, structural changes, and charge flows during the charging and discharging processes for a new high-capacity cathode material, Li8ZrO6 (LZO), which we study both pure and yttrium-doped. We quantum mechanically calculated the stable delithiated configurations, the delithiation energy, the charge flow during delithiation, and the stability of the delithiated materials. We find that Li atoms are easier to extract from tetrahedral sites than octahedral ones. We calculate a large average voltage of 4.04 eV vs Li/Li(+) for delithiation of the first Li atom in a primitive cell, which is confirmed by galvanostatic charge/discharge cycling data. Energy calculations indicate that topotactic delithiation is kinetically favored over decomposition into Li, ZrO2, and O2 during the charging process, although the thermodynamic energy of the topotactic reaction is less favorable. When one or two lithium atoms are extracted from a primitive cell of LZO, its volume and structure change little, whereas extraction of the third lithium greatly distorts the layered structure. The Li6ZrO6 and Li5ZrO6 delithiation products can be thermodynamically metastable to release of O2. Experimentally, materials with sufficiently small particle size for efficient delithiation and relithiation were achieved within an yttrium-doped LZO/carbon composite cathode that exhibited an initial discharge capacity of at least 200 mAh/g over the first 10 cycles, with 142 mAh/g maintained after 60 cycles. Computations predict that during the charging process, the oxygen ion near the Li vacancy is oxidized for both pure LZO and yttrium-doped LZO, which leads to a small-polaron hole.

  12. Prussian blue nanocubes as cathode materials for aqueous Na-Zn hybrid batteries

    NASA Astrophysics Data System (ADS)

    Wang, Li-Ping; Wang, Peng-Fei; Wang, Tai-Shan; Yin, Ya-Xia; Guo, Yu-Guo; Wang, Chun-Ru

    2017-07-01

    Rechargeable aqueous battery is very attractive as a promising alternative energy storage system, based on its safety and environmental-friendly properties. An aqueous rechargeable Na-Zn hybrid battery is assembled by using Prussian blue nanocubes and metallic zinc as cathode and anode, respectively. This Na-Zn cell delivers a high specific capacity of 73.5 mA h g-1 and a good cycling stability (ca. 80% capacity retention after 1000 cycles at 300 mA g-1) due to the impressive structure stability of Prussian blue nanocubes. These remarkable features are realized by a simple synthetic method and a feasible battery manufacturing process, which can provide guidance for the development of rechargeable batteries in a large scale.

  13. A new cathode material for super-valent battery based on aluminium ion intercalation and deintercalation

    PubMed Central

    Wang, Wei; Jiang, Bo; Xiong, Weiyi; Sun, He; Lin, Zheshuai; Hu, Liwen; Tu, Jiguo; Hou, Jungang; Zhu, Hongmin; Jiao, Shuqiang

    2013-01-01

    Due to their small footprint and flexible siting, rechargeable batteries are attractive for energy storage systems. A super-valent battery based on aluminium ion intercalation and deintercalation is proposed in this work with VO2 as cathode and high-purity Al foil as anode. First-principles calculations are also employed to theoretically investigate the crystal structure change and the insertion-extraction mechanism of Al ions in the super-valent battery. Long cycle life, low cost and good capacity are achieved in this battery system. At the current density of 50 mAg−1, the discharge capacity remains 116 mAhg−1 after 100 cycles. Comparing to monovalent Li-ion battery, the super-valent battery has the potential to deliver more charges and gain higher specific capacity. PMID:24287676

  14. New lithium iron pyrophosphate as 3.5 V class cathode material for lithium ion battery.

    PubMed

    Nishimura, Shin-ichi; Nakamura, Megumi; Natsui, Ryuichi; Yamada, Atsuo

    2010-10-06

    A new pyrophosphate compound Li(2)FeP(2)O(7) was synthesized by a conventional solid-state reaction, and its crystal structure was determined. Its reversible electrode operation at ca. 3.5 V vs Li was identified with the capacity of a one-electron theoretical value of 110 mAh g(-1) even for ca. 1 μm particles without any special efforts such as nanosizing or carbon coating. Li(2)FeP(2)O(7) and its derivatives should provide a new platform for related lithium battery electrode research and could be potential competitors to commercial olivine LiFePO(4), which has been recognized as the most promising positive cathode for a lithium-ion battery system for large-scale applications, such as plug-in hybrid electric vehicles.

  15. A new cathode material for super-valent battery based on aluminium ion intercalation and deintercalation.

    PubMed

    Wang, Wei; Jiang, Bo; Xiong, Weiyi; Sun, He; Lin, Zheshuai; Hu, Liwen; Tu, Jiguo; Hou, Jungang; Zhu, Hongmin; Jiao, Shuqiang

    2013-11-29

    Due to their small footprint and flexible siting, rechargeable batteries are attractive for energy storage systems. A super-valent battery based on aluminium ion intercalation and deintercalation is proposed in this work with VO2 as cathode and high-purity Al foil as anode. First-principles calculations are also employed to theoretically investigate the crystal structure change and the insertion-extraction mechanism of Al ions in the super-valent battery. Long cycle life, low cost and good capacity are achieved in this battery system. At the current density of 50 mAg(-1), the discharge capacity remains 116 mAhg(-1) after 100 cycles. Comparing to monovalent Li-ion battery, the super-valent battery has the potential to deliver more charges and gain higher specific capacity.

  16. Cathodes - Technological review

    NASA Astrophysics Data System (ADS)

    Cherkouk, Charaf; Nestler, Tina

    2014-06-01

    Lithium cobalt oxide (LiCoO2) was already used in the first commercialized Li-ion battery by SONY in 1990. Still, it is the most frequently used cathode material nowadays. However, LiCoO2 is intrinsically unstable in the charged state, especially at elevated temperatures and in the overcharged state causing volume changes and transport limitation for high power batteries. In this paper, some technological aspects with large impact on cell performance from the cathode material point of view will be reviewed. At first it will be focused on the degradation processes and life-time mechanisms of the cathode material LiCoO2. Electrochemical and structural results on commercial Li-ion batteries recorded during the cycling will be discussed. Thereafter, advanced nanomaterials for new cathode materials will be presented.

  17. Cathodes - Technological review

    SciTech Connect

    Cherkouk, Charaf; Nestler, Tina

    2014-06-16

    Lithium cobalt oxide (LiCoO{sub 2}) was already used in the first commercialized Li-ion battery by SONY in 1990. Still, it is the most frequently used cathode material nowadays. However, LiCoO{sub 2} is intrinsically unstable in the charged state, especially at elevated temperatures and in the overcharged state causing volume changes and transport limitation for high power batteries. In this paper, some technological aspects with large impact on cell performance from the cathode material point of view will be reviewed. At first it will be focused on the degradation processes and life-time mechanisms of the cathode material LiCoO{sub 2}. Electrochemical and structural results on commercial Li-ion batteries recorded during the cycling will be discussed. Thereafter, advanced nanomaterials for new cathode materials will be presented.

  18. A new lithium-rich anti-spinel in Li-O-Br system.

    PubMed

    Zhang, J; Zhu, J; Wang, L; Zhao, Y

    2015-06-14

    In spinel-type materials currently known, the divalent anions are arranged in a closed-pack lattice and cations of various valences occupy some or all of the tetrahedral and octahedral sites. We report here the first discovery of an "electronically inverted" anti-spinel. The new material, crystallized in a defect spinel structure, was obtained from the dehydration of Li5Br(OH)4 under moderate pressure and temperature conditions.

  19. Electrochemical properties of ZrO 2-coated LiNi 0.8Co 0.2O 2 cathode materials

    NASA Astrophysics Data System (ADS)

    Lee, Sang Myoung; Oh, Si Hyoung; Ahn, Jae Pyoung; Cho, Won Il; Jang, Ho

    The effect of a ZrO 2 coating on the structure and electrochemical properties of the cathode material LiNi 0.8Co 0.2O 2 was investigated using EPMA, TEM, XRD, and electrochemical impedance spectroscopy (EIS). In particular, we focused on the distribution of the ZrO 2 on the particle surface to study the relationship between electrochemical properties of the coated cathode and the distribution of the coating materials in the particle. Based on the results from composition analysis and electrochemical tests, it was found that the coating layer consisted of nano-sized ZrO 2 particles attached nonuniformly to the particle surface and the ZrO 2 layer significantly improved the electrochemical properties of the cathode by suppressing the impedance growth at the interface between the electrodes and the electrolyte.

  20. Spinel: gaining momentum in optical applications

    NASA Astrophysics Data System (ADS)

    Patterson, Mark C. L.; DiGiovanni, Anthony A.; Fehrenbacher, Lawrence; Roy, Don W.

    2003-09-01

    There are presently three materials (sapphire, ALON and spinel) which exhibit a desirable combination of material properties such as hardness, strength, and transmission in MWIR that are considered for various window/dome applications. Of the three, sapphire exists in a number of service applications. It is, however, the most expensive of the three and depending on application, can have significant drawbacks owing to its birefringent nature. ALON, by comparison is less expensive, benefits from greater development efforts, is an easily shaped polycrystalline ceramic, optically does not possess the birefringent nature of sapphire, but requires very high formation temperatures for the starting powders and equally long processing times for fabricated parts. The remaining material, transparent spinel, offers improved optical performance over the spectrum from UV to MWIR, comparable mechanical properties, and can be fabricated at much lower temperatures and shorter times than the other materials making it less expensive to produce. Data will be described which compares the transparency and mechanical properties and discusses the relevant processing efforts for spinel products.

  1. Atomic-Resolution Visualization of Distinctive Chemical Mixing Behavior of Ni, Co and Mn with Li in Layered Lithium Transition-Metal Oxide Cathode Materials

    SciTech Connect

    Yan, Pengfei; Zheng, Jianming; Lv, Dongping; Wei, Yi; Zheng, Jiaxin; Wang, Zhiguo; Kuppan, Saravanan; Yu, Jianguo; Luo, Langli; Edwards, Danny J.; Olszta, Matthew J.; Amine, Khalil; Liu, Jun; Xiao, Jie; Pan, Feng; Chen, Guoying; Zhang, Jiguang; Wang, Chong M.

    2015-07-06

    Capacity and voltage fading of layer structured cathode based on lithium transition metal oxide is closely related to the lattice position and migration behavior of the transition metal ions. However, it is scarcely clear about the behavior of each of these transition metal ions. We report direct atomic resolution visualization of interatomic layer mixing of transition metal (Ni, Co, Mn) and lithium ions in layer structured oxide cathodes for lithium ion batteries. Using chemical imaging with aberration corrected scanning transmission electron microscope (STEM) and DFT calculations, we discovered that in the layered cathodes, Mn and Co tend to reside almost exclusively at the lattice site of transition metal (TM) layer in the structure or little interlayer mixing with Li. In contrast, Ni shows high degree of interlayer mixing with Li. The fraction of Ni ions reside in the Li layer followed a near linear dependence on total Ni concentration before reaching saturation. The observed distinctively different behavior of Ni with respect to Co and Mn provides new insights on both capacity and voltage fade in this class of cathode materials based on lithium and TM oxides, therefore providing scientific basis for selective tailoring of oxide cathode materials for enhanced performance.

  2. Facile molten salt synthesis of Li2NiTiO4 cathode material for Li-ion batteries

    PubMed Central

    2014-01-01

    Well-crystallized Li2NiTiO4 nanoparticles are rapidly synthesized by a molten salt method using a mixture of NaCl and KCl salts. X-ray diffraction pattern and scanning electron microscopic image show that Li2NiTiO4 has a cubic rock salt structure with an average particle size of ca. 50 nm. Conductive carbon-coated Li2NiTiO4 is obtained by a facile ball milling method. As a novel 4 V positive cathode material for Li-ion batteries, the Li2NiTiO4/C delivers high discharge capacities of 115 mAh g-1 at room temperature and 138 mAh g-1 and 50°C, along with a superior cyclability. PMID:24855459

  3. Study of the Durability of Doped Lanthanum Manganite and Cobaltite Cathode Materials under ''Real World'' Air Exposure Atmospheres

    SciTech Connect

    Singh, Prabhakar; Mahapatra, Manoj; Ramprasad, Rampi; Minh, Nguyen; Misture, Scott

    2014-11-30

    The overall objective of the program is to develop and validate mechanisms responsible for the overall structural and chemical degradation of lanthanum manganite as well as lanthanum ferrite cobaltite based cathode when exposed to “real world” air atmosphere exposure conditions during SOFC systems operation. Of particular interest are the evaluation and analysis of degradation phenomena related to and responsible for (a) products formation and interactions with air contaminants, (b) dopant segregation and oxide exolution at free surfaces, (c) cation interdiffusion and reaction products formation at the buried interfaces, (d) interface morphology changes, lattice transformation and the development of interfacial porosity and (e) micro-cracking and delamination from the stack repeat units. Reaction processes have been studied using electrochemical and high temperature materials compatibility tests followed by structural and chemical characterization. Degradation hypothesis has been proposed and validated through further experimentation and computational simulation.

  4. Na2MnSiO4 as an attractive high capacity cathode material for sodium-ion battery

    NASA Astrophysics Data System (ADS)

    Law, Markas; Ramar, Vishwanathan; Balaya, Palani

    2017-08-01

    Here we report a polyanion-based cathode material for sodium-ion batteries, Na2MnSiO4, registering impressive sodium storage performances with discharge capacity of 210 mAh g-1 at an average voltage of 3 V at 0.1 C, along with excellent long-term cycling stability (500 cycles at 1 C). Insertion/extraction of ∼1.5 mol of sodium ion per formula unit of the silicate-based compound is reported and the utilisation of Mn2+ ⇋ Mn4+ redox couple is also demonstrated by ex-situ XPS. Besides, this study involves a systematic investigation of influence of the electrolyte additive (with different content) on the sodium storage performance of Na2MnSiO4. The electrolyte additive forms an optimum protective passivation film on the electrode surface, successfully reducing manganese dissolution.

  5. Cu doped V2O5 flowers as cathode material for high-performance lithium ion batteries.

    PubMed

    Yu, Hong; Rui, Xianhong; Tan, Huiteng; Chen, Jing; Huang, Xin; Xu, Chen; Liu, Weiling; Yu, Denis Y W; Hng, Huey Hoon; Hoster, Harry E; Yan, Qingyu

    2013-06-07

    Hierarchical Cu doped vanadium pentoxide (V2O5) flowers were prepared via a simple hydrothermal approach followed by an annealing process. The flower precursors are self-assembled with 1D nanobelts surrounding a central core. The morphological evolution is investigated and a plausible mechanism is proposed. As the cathode material for lithium ion batteries, the Cu doped V2O5 samples exhibit improved electrochemical performance compared to the un-doped ones. Among them Cu0.02V1.98O5 delivered higher reversible specific capacities, better cycling stabilities and excellent rate capabilities, e.g. 97 mA h g(-1) at 20.0 C.

  6. Facile molten salt synthesis of Li2NiTiO4 cathode material for Li-ion batteries.

    PubMed

    Wang, Yanming; Wang, Yajing; Wang, Fei

    2014-01-01

    Well-crystallized Li2NiTiO4 nanoparticles are rapidly synthesized by a molten salt method using a mixture of NaCl and KCl salts. X-ray diffraction pattern and scanning electron microscopic image show that Li2NiTiO4 has a cubic rock salt structure with an average particle size of ca. 50 nm. Conductive carbon-coated Li2NiTiO4 is obtained by a facile ball milling method. As a novel 4 V positive cathode material for Li-ion batteries, the Li2NiTiO4/C delivers high discharge capacities of 115 mAh g(-1) at room temperature and 138 mAh g(-1) and 50°C, along with a superior cyclability.

  7. Plasma sprayed manganese-cobalt spinel coatings: Process sensitivity on phase, electrical and protective performance

    NASA Astrophysics Data System (ADS)

    Han, Su Jung; Pala, Zdenek; Sampath, Sanjay

    2016-02-01

    Manganese cobalt spinel (Mn1.5Co1.5O4, MCO) coatings are prepared by the air plasma spray (APS) process to examine their efficacy in serving as protective coatings from Cr-poisoning of the cathode side in intermediate temperature-solid oxide fuel cells (IT-SOFCs). These complex oxides are susceptible to process induced stoichiometric and phase changes which affect their functional performance. To critically examine these effects, MCO coatings are produced with deliberate modifications to the spray process parameters to explore relationship among process conditions, microstructure and functional properties. The resultant interplay among particle thermal and kinetic energies are captured through process maps, which serve to characterize the parametric effects on properties. The results show significant changes to the chemistry and phase composition of the deposited material resulting from preferential evaporation of oxygen. Post deposition annealing recovers oxygen in the coatings and allows partial recovery of the spinel phase, which is confirmed through thermo-gravimetric analysis (TGA)/differential scanning calorimetry (DSC), X-ray Diffraction (XRD), and magnetic hysteresis measurements. In addition, coatings with high density after sintering show excellent electrical conductivity of 40 S cm-1 at 800 °C while simultaneously providing requisite protection characteristics against Cr-poisoning. This study provides a framework for optimal evaluation of MCO coatings in intermediate temperature SOFCs.

  8. Conducting Polymers Crosslinked with Sulfur as Cathode Materials for High-Rate, Ultralong-Life Lithium-Sulfur Batteries.

    PubMed

    Zeng, Shuaibo; Li, Ligui; Xie, Lihong; Zhao, Dengke; Wang, Nan; Chen, Shaowei

    2017-09-11

    Low electrical conductivity and a lack of chemical confinement are two major factors that limit the rate performances and cycling stabilities of cathode materials in lithium-sulfur (Li-S) batteries. Herein, sulfur is copolymerized with poly(m-aminothiophenol) (PMAT) nanoplates through inverse vulcanization to form the highly crosslinked copolymer cp(S-PMAT) in which approximately 80 wt % of the feed sulfur is bonded chemically to the thiol groups of PMAT. A cp(S-PMAT)/C-based cathode exhibits a high discharge capacity of 1240 mAh g(-1) at 0.1 C and remarkable rate capacities of 880 mAh g(-1) at 1 C and 600 mAh g(-1) at 5 C. Moreover, it can retain a capacity of 495 mAh g(-1) after 1000 deep discharge-charge cycles at 2 C; this corresponds to a retention of 66.9 % and a decay rate of only 0.040 % per cycle. Such a remarkable rate performance is attributed to the highly conductive pathways of PMAT nanoplates, and the excellent cycling stability is ascribed mainly to the chemical confinement of sulfur through a large number of stable covalent bonds between sulfur and the thiol groups of PMAT. The results suggest that this strategy is a viable paradigm for the design and engineering of conducting polymers with reactive functional groups as effective electrode materials for high-performance Li-S batteries. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Vanadium Oxyfluoride/Few-Layer Graphene Composite as a High-Performance Cathode Material for Lithium Batteries.

    PubMed

    Cambaz, Musa Ali; Vinayan, B P; Clemens, Oliver; Munnangi, Anji Reddy; Chakravadhanula, Venkata Sai Kiran; Kübel, Christian; Fichtner, Maximilian

    2016-04-18

    Metal oxyfluoride compounds are gathering significant interest as cathode materials for lithium ion batteries at the moment because of their high theoretical capacity and resulting high energy density. In this regard, a new and direct approach is presented to synthesize phase-pure vanadium oxyfluoride (VO2F). The structure of VO2F was identified by Rietveld refinement of the powder X-ray diffraction (XRD) pattern. It crystallizes in a perovskite-type structure with disorder of the oxide and fluoride ions. The as-synthesized VO2F was tested as a cathode material for lithium ion batteries after being surface-coated with few-layer graphene. The VO2F delivered a first discharge capacity of 254 mA h g(-1) and a reversible capacity of 208 mA h g(-1) at a rate of C/20 for the first 20 cycles with an average discharge voltage of 2.84 V, yielding an energy density of 591 W h kg(-1). Improved rate capability that outperforms the previous report has been achieved, showing a discharge capacity of 150 mA h g(-1) for 1 C. The structural changes during lithium insertion and extraction were monitored by ex-situ XRD analysis of the electrodes discharged and charged to various stages. Lithium insertion results in an irreversible structural change of the anion lattice from (3)/4 cubic close packing to hexagonal close packing to accommodate the inserted lithium ions while keeping the overall space-group symmetry. For the first time we have revealed a structural change for the ReO3-type structure of as-prepared VO2F to the RhF3 structure after lithiation/delithiation, with structural changes that have not been observed in previous reports. Furthermore, the new synthetic approach described here would be a platform for the synthesis of new oxyfluoride compounds.

  10. First principle study of LiXS2 (X = Ga, In) as cathode materials for Li ion batteries

    NASA Astrophysics Data System (ADS)

    Feng-Ya, Rao; Fang-Hua, Ning; Li-Wei, Jiang; Xiang-Ming, Zeng; Mu-Sheng, Wu; Bo, Xu; Chu-Ying, Ouyang

    2016-02-01

    From first principle calculations, we demonstrate that LiXS2 (X = Ga, In) compounds have potential applications as cathode materials for Li ion batteries. It is shown that Li can be extracted from the LiXS2 lattice with relatively small volume change and the XS4 tetrahedron structure framework remains stable upon delithiation. The theoretical capacity and average intercalation potential of the LiGaS2 (LiInS2) cathode are 190.4 (144.2) mAh/g and 3.50 V (3.53 V). The electronic structures of the LiXS2 are insulating with band gaps of 2.88 eV and 1.99 eV for X = Ga and In, respectively. However, Li vacancies, which are formed through delithiation, change the electronic structure substantially from insulating to metallic structure, indicating that the electrical conductivities of the LiXS2 compounds should be good during cycling. Li ion migration energy barriers are also calculated, and the results show that Li ion diffusions in the LiXS2 compounds can be as good as those in the currently widely used electrode materials. Project supported by the National High Technology and Development Key Program, China (Grant No. 2015AA034201), the National Natural Science Foundation of China (Grant Nos. 11234013 and 11264014), the Natural Science Foundation of Jiangxi Province, China (Grant Nos. 20133ACB21010, 20142BAB212002, and 20132BAB212005), and the Foundation of Jiangxi Provincial Education Committee, China (Grant Nos. GJJ14254 and KJLD14024).

  11. Electrolytic Reduction of Spent Nuclear Oxide Fuel -- Effects of Fuel Form and Cathode Containment Materials on Bench-Scale Operations

    SciTech Connect

    S. D. Herrmann

    2007-09-01

    A collaborative effort between the Idaho National Laboratory (INL) and Korea Atomic Energy Research Institute (KAERI) is underway per an International Nuclear Energy Research Initiative to advance the development of a pyrochemical process for the treatment of spent nuclear oxide fuel. To assess the effects of specific process parameters that differ between oxide reduction operations at INL and KAERI, a series of 4 electrolytic reduction runs will be performed with a single salt loading of LiCl-Li2O at 650 °C using a test apparatus located inside of a hot cell at INL. The spent oxide fuel for the tests will be irradiated UO2 that has been subjected to a voloxidation process to form U3O8. The primary variables in the 4 electrolytic reduction runs will be fuel basket containment material and Li2O concentration in the LiCl salt. All 4 runs will be performed with comparable fuel loadings (approximately 50 g) and fuel compositions and will utilize a platinum anode and a Ni/NiO reference electrode. The first 2 runs will elucidate the effect of fuel form on the electrolytic reduction process by comparison of the above test results with U3O8 versus results from previous tests with UO2. The first 3 runs will investigate the impact that the cathode containment material has on the electrolytic reduction of spent oxide fuel. The 3rd and 4th runs will investigate the effect of Li2O concentration on the reduction process with a porous MgO cathode containment.

  12. Preparation of Li-rich layered-layered type xLi2MnO3·(1-x)LiMnO2 nanorods and its electrochemical performance as cathode material for Li-ion battery

    NASA Astrophysics Data System (ADS)

    Yang, Fan; Zhang, Qinggang; Hu, Xiaohong; Peng, Tianyou; Liu, Jianqiang

    2017-06-01

    Layered-layered type xLi2MnO3·(1-x)LiMnO2 (x = 0.91, 0.78, 0.67, 0.54, 0.42, and 0.32) nanorods with a diameter of 100-200 nm and length of 400-1000 nm are prepared through a pyrolysis reduction process of monoclinic Li2MnO3 (m-Li2MnO3) nanorods. All the synthesized xLi2MnO3·(1-x)LiMnO2 nanorods exhibit the main characteristic diffraction peaks of m-Li2MnO3 in addition to some weak peaks attributable to m-LiMnO2 especially for those composites with x < 0.67. When used as cathode material of Li-ion battery, those xLi2MnO3·(1-x)LiMnO2 nanorods show an initial charge/discharge profile similar to the Li-rich solid solution in the voltage window of 2.0-4.8 V. The m-LiMnO2 portion in those synthesized composites can significantly enhance the reversible capacity but lower the cyclic stability, while the m-Li2MnO3 portion can improve the cyclic stability due to its retardation effect of the layered-to-spinel transformation during the charge/discharge processes, and thus xLi2MnO3·(1-x)LiMnO2 nanorods with x = 0.54 exhibits the best cyclic and rate performance since it contains appropriate m-Li2MnO3/m-LiMnO2 contents to balance the reversible capacity and Jahn-Teller effect. The present findings demonstrate an effective strategy for the development of low-cost pure Mn-based Li-rich layered cathode materials with adjustable reversible capacity, cyclic and rate performance by tailoring the composition.

  13. On the Utility of Spinel Oxide Hosts for Magnesium-Ion Batteries.

    PubMed

    Knight, James C; Therese, Soosairaj; Manthiram, Arumugam

    2015-10-21

    There is immense interest to develop Mg-ion batteries, but finding suitable cathode materials has been a challenge. The spinel structure has many advantages for ion insertion and has been successfully used in Li-ion batteries. We present here findings on the attempts to extract Mg from MgMn2O4-based spinels with acid (H2SO4) and with NO2BF4. The acid treatment was able to fully remove all Mg from MgMn2O4 by following a mechanism involving the disproportionation of Mn(3+), and the extraction rate decreased with increasing cation disorder. Samples with additional Mg(2+) ions in the octahedral sites (e.g., Mg1.1Mn1.9O4 and Mg1.5Mn1.5O4) also exhibit complete or near complete demagnesiation due to an additional mechanism involving ion exchange of Mg(2+) by H(+), but no Mg could be extracted from MgMnAlO4 due to the disruption of Mn-Mn interaction/contact across shared octahedral edges. In contrast, no Mg could be extracted with the oxidizing agent NO2BF4 from MgMn2O4 or Mg1.5Mn1.5O4 as the electrostatic repulsion between the divalent Mg(2+) ions prevents Mg(2+) diffusion through the 16c octahedral sites, unlike Li(+) diffusion, suggesting that spinels may not serve as potential hosts for Mg-ion batteries. The ability to extract Mg with acid in contrast to that with NO2BF4 is attributed to Mn dissolution from the lattice and the consequent reduction in electrostatic repulsion. The findings could provide insights toward the design of Mg hosts for Mg-ion batteries.

  14. Improved electrochemical performance of spinel LiMn1.5Ni0.5O4 through MgF2 nano-coating

    DOE PAGES

    Wu, Qing; Zhang, Xiaoping; Sun, Shuwei; ...

    2015-07-08

    In this paper, a spinel LiMn1.5Ni0.5O4 (LMNO) cathode material synthesized by a sol–gel method is modified by MgF2 nano-coating via a wet coating strategy. The results of X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM) showed that the MgF2 nano-coating layers do not physically change the bulk structure of the pristine material. Compared with the pristine compound, the MgF2-coated LMNO electrodes display enhanced cycling stabilities. Particularly, the 5 wt% MgF2-coated LMNO demonstrates the best reversibility, with a capacity retention of 89.9% after 100 cycles, much higher than that of themore » pristine material, 69.3%. The dQ/dV analysis and apparent Li+ diffusion coefficient calculation prove that the kinetic properties are enhanced after MgF2 surface modification, which partly explains the improved electrochemical performances. Electrochemical impedance spectroscopy (EIS) and Fourier transform infrared spectroscopy (FTIR) data confirm that the MgF2 coating layer helps in suppressing the fast growth of the solid electrolyte interface (SEI) film in repeated cycling, which effectively stabilizes the spinel structure. Finally and additionally, differential scanning calorimetry (DSC) tests show that the MgF2 nano-coating layer also helps in enhancing the thermal stability of the LMNO cathode.« less

  15. Hydrogen hollow cathode ion source

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J., Jr.; Sovey, J. S.; Roman, R. F. (Inventor)

    1980-01-01

    A source of hydrogen ions is disclosed and includes a chamber having at one end a cathode which provides electrons and through which hydrogen gas flows into the chamber. Screen and accelerator grids are provided at the other end of the chamber. A baffle plate is disposed between the cathode and the grids and a cylindrical baffle is disposed coaxially with the cathode at the one end of the chamber. The cylindrical baffle is of greater diameter than the baffle plate to provide discharge impedance and also to protect the cathode from ion flux. An anode electrode draws the electrons away from the cathode. The hollow cathode includes a tubular insert of tungsten impregnated with a low work function material to provide ample electrons. A heater is provided around the hollow cathode to initiate electron emission from the low work function material.

  16. Evaluation of wear rates and mechanisms of titanium diboride-graphite composite materials proposed for use as cathodes in Hall-Heroult cells

    SciTech Connect

    Pool, K.H.; Brimhall, J.L.; Raney, P.J.; Hart, P.E.

    1987-01-01

    Purpose of this study was to measure the initial wear rates of TiB/sub 2/ carbon-containing cathode materials (TiB/sub 2/-G) under electrolytic conditions. Parameters evaluated included bath ratio, current density, and aluminum pad thickness. In order to measure initial wear rates, the tests were limited to 8 h.

  17. SiO2-coated sulfur particles with mildly reduced graphene oxide as a cathode material for lithium-sulfur batteries.

    PubMed

    Campbell, Brennan; Bell, Jeffrey; Bay, Hamed Hosseini; Favors, Zachary; Ionescu, Robert; Ozkan, Cengiz S; Ozkan, Mihrimah

    2015-04-28

    For the first time, SiO2-coated sulfur particles (SCSPs) were fabricated via a facile two-step wet chemical process for application as a novel lithium-sulfur cathode material. With the addition of mildly reduced graphene oxide (mrGO), SCSPs demonstrate even greater cycling stability, maintaining over 700 mA h g(-1) after the 50(th) cycle.

  18. SiO2-coated sulfur particles with mildly reduced graphene oxide as a cathode material for lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Campbell, Brennan; Bell, Jeffrey; Hosseini Bay, Hamed; Favors, Zachary; Ionescu, Robert; Ozkan, Cengiz S.; Ozkan, Mihrimah

    2015-04-01

    For the first time, SiO2-coated sulfur particles (SCSPs) were fabricated via a facile two-step wet chemical process for application as a novel lithium-sulfur cathode material. With the addition of mildly reduced graphene oxide (mrGO), SCSPs demonstrate even greater cycling stability, maintaining over 700 mA h g-1 after the 50th cycle.

  19. Structural changes and thermal stability of charged LiNixMnyCozO2 cathode materials studied by combined in situ time-resolved XRD and mass spectroscopy

    SciTech Connect

    Bak, Seong -Min; Hu, Enyuan; Zhou, Yongning; Yu, Xiqian; Senanayake, Sanjaya D.; Cho, Sung -Jin; Kim, Kwang -Bum; Chung, Kyung Yoon; Yang, Xiao -Qing; Nam, Kyung -Wan

    2014-11-24

    Thermal stability of charged LiNixMnyCozO2 (NMC, with x + y + z = 1, x:y:z = 4:3:3 (NMC433), 5:3:2 (NMC532), 6:2:2 (NMC622), and 8:1:1 (NMC811)) cathode materials is systematically studied using combined in situ time- resolved X-ray diffraction and mass spectroscopy (TR-XRD/MS) techniques upon heating up to 600 °C. The TR-XRD/MS results indicate that the content of Ni, Co, and Mn significantly affects both the structural changes and the oxygen release features during heating: the more Ni and less Co and Mn, the lower the onset temperature of the phase transition (i.e., thermal decomposition) and the larger amount of oxygen release. Interestingly, the NMC532 seems to be the optimized composition to maintain a reasonably good thermal stability, comparable to the low-nickel-content materials (e.g., NMC333 and NMC433), while having a high capacity close to the high-nickel-content materials (e.g., NMC811 and NMC622). The origin of the thermal decomposition of NMC cathode materials was elucidated by the changes in the oxidation states of each transition metal (TM) cations (i.e., Ni, Co, and Mn) and their site preferences during thermal decomposition. It is revealed that Mn ions mainly occupy the 3a octahedral sites of a layered structure (R3¯m) but Co ions prefer to migrate to the 8a tetrahedral sites of a spinel structure (Fd3¯m) during the thermal decomposition. Such element-dependent cation migration plays a very important role in the thermal stability of NMC cathode materials. The reasonably good thermal stability and high capacity characteristics of the NMC532 composition is originated from the well-balanced ratio of nickel content to manganese and cobalt contents. As a result, this systematic study provides insight into the rational design of NMC-based cathode materials with a desired balance between thermal stability and high energy density.

  20. Hydroxyl-decorated graphene systems as