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Sample records for spinel cathode materials

  1. New inverse spinel cathode materials for rechargeable lithium batteries

    NASA Astrophysics Data System (ADS)

    Fey, G. T. K.; Wang, K. S.; Yang, S. M.

    The synthesis, characterization, and electrochemical properties of LiNi yCo 1 - yVO 4 (0 ≤ y ≤ 1) as the new cathode materials for rechargeable lithium batteries were investigated. A series of LiNi yCo 1 - yVO 4 ( y = 0.1 - 0.9) compounds were synthesized by either a solid-state reaction of LiNi yCo 1 - yO 2 and V 2O 5 at 800 °C for 12 h or a solution coprecipitation of LiOH · H 2O, Ni(NO 3) 2 · 6H 2O, Co(NO 3) 2 · 6H 2O and NH 4VO 3, followed by heating the precipitate at 500 °C for 48 h. The products from both preparation methods were analyzed by scanning electron microcopy and inductively-coupled plasma-atomic emission spectroscopy. These compounds are inverse spinels based on the results from Rietveld analysis and the fact that the cubic lattice constant a is a linear function of stoichiometry y in LiNi yCo 1 - yVO 4. Either a 1 M LiC1O 4-EC + PC (1:1) or 1 M LiBF 4-EC + PC + DMC (1:1:4) electrolyte can be used as the electrolyte for Li/LiNi yCo 1 - yVO 4 cells up to y = 0.7. The charge and discharge capacity of a Li/1 M LiBF 4-EC + PC + DMC (1:1:4) /LiNi 0.5Co 0.5VO 4 cell were 43.8 and 34.8 mAh/g, respectively, when the cathode material was prepared by the low temperature coprecipitation method.

  2. Ultrathin spinel membrane-encapsulated layered lithium-rich cathode material for advanced Li-ion batteries.

    PubMed

    Wu, Feng; Li, Ning; Su, Yuefeng; Zhang, Linjing; Bao, Liying; Wang, Jing; Chen, Lai; Zheng, Yu; Dai, Liqin; Peng, Jingyuan; Chen, Shi

    2014-06-11

    Lack of high-performance cathode materials has become a technological bottleneck for the commercial development of advanced Li-ion batteries. We have proposed a biomimetic design and versatile synthesis of ultrathin spinel membrane-encapsulated layered lithium-rich cathode, a modification by nanocoating. The ultrathin spinel membrane is attributed to the superior high reversible capacity (over 290 mAh g(-1)), outstanding rate capability, and excellent cycling ability of this cathode, and even the stubborn illnesses of the layered lithium-rich cathode, such as voltage decay and thermal instability, are found to be relieved as well. This cathode is feasible to construct high-energy and high-power Li-ion batteries. PMID:24844948

  3. High power 4.7 V nanostructured spinel lithium manganese nickel oxide lithium-ion battery cathode materials

    NASA Astrophysics Data System (ADS)

    Kunduraci, Muharrem

    Nanostructured LiMn1.5+deltaNi0.5-deltaO 4 spinel powders were synthesized by a solution based chemistry method called modified Pechini. The impacts of processing parameters such as synthesis temperature, oxygen-partial-pressure and mole ratio of ethylene glycol to citric acid on the morphology, structure and properties of spinel materials have been studied thoroughly via various in-situ and ex-situ characterization techniques. Later, these parameters were tied with the electrochemical properties of spinel electrodes. After optimization of processing steps and glycol/acid ratio, a unique mesoporous morphology with interconnected nanoparticles were successfully obtained. Such morphology was found to be very conducive to achieve high power density lithium-ion battery spinel cathodes. This was attributed to (i) large number of mesoporosities that favor electrolyte penetration, thereby enabling better wetting of spinel cathodes and faster lithium ion transfer at electrolyte/cathode interface and (ii) particle interconnectivity that allows continuous electron transport, which becomes highly critical especially at high current rates. The synthesis temperature and oxygen-partial-pressure were found to affect the structure significantly. Depending on the ordering/disordering of transition metal ions on octahedral sites, spinels were assigned to either ordered P4 332 or disordered Fd3m space groups. The spinel of the two symmetry groups differed significantly in fast discharge rate capability. In an effort to identify the origin of this electrochemical disparity, intensive characterizations of both structures were undertaken (in-situ: XRD, Impedance spectroscopy, Raman; ex-situ: XRD, FTIR, TGA, electronic conductivity and lithium diffusivity and more). The poor performance of the ordered phase was attributed to its intrinsic properties, namely lower electronic conductivity and lithium diffusion coefficient (DLi). Regarding the former, the mechanism of electron conduction in

  4. 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.

  5. 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

  6. Structure of electrolyte decomposition products on high voltage spinel cathode materials determined by in situ neutron reflectometry

    NASA Astrophysics Data System (ADS)

    Browning, Jim; Veith, Gabriel; Baggetto, Loic; Dudney, Nancy; Tenhaeff, Wyatt

    2012-02-01

    Interfacial reactions on electrical energy storage (EES) materials mediate their stability, durability, and cycleablity. Understanding these reactions in situ is difficult since they occur at the liquid-solid interface of an optically absorbing material that hinders the use of techniques such as infra-red spectroscopy. Furthermore, since the interfaces involve liquids classic vacuum-based analytical methods can only probe reaction products, which are stable under vacuum. Here, we present the results of an in situ neutron reflectometry study detailing the formation of a thick solid-electrolyte interphase (SEI) on a high voltage spinel cathode material. The cathode/electrolyte system used in this study is a LiMn1.5Ni0.5O4 thin film subjected to a 1.2 molar LiPF6 in 1:1 ethylene carbonate - dimethyl carbonate electrolyte solution.

  7. 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.

  8. Solution-combustion synthesized aluminium-doped spinel (LiAl x Mn2- x O4) as a high-performance lithium-ion battery cathode material

    NASA Astrophysics Data System (ADS)

    Kebede, Mesfin A.; Phasha, Maje J.; Kunjuzwa, Niki; Mathe, Mkhulu K.; Ozoemena, Kenneth I.

    2015-10-01

    High-performing LiAl x Mn2- x O4 ( x = 0, 0.125, 0.25, 0.375, and 0.5) spinel cathode materials for lithium-ion battery were developed using a solution combustion method. The as-synthesized cathode materials have spinel cubic structure of LiMn2O4 without any impurity peak and accompanied with peak shift as doping with aluminium. LiAl0.375Mn1.625O4 (first cycle capacity = 113.1 mAh g-1) retains 85 % (96.2 mAh g-1), while pristine LiMn2O4 electrode (first cycle capacity = 135.8 mAh g-1) fades quickly and retains only 54 % (73.9 mAh g-1) after 50 cycles. The electrochemical performance of all the cathode samples prepared using the SCM is comparable to those reported for Al-doped LiMn2O4 spinel cathode materials. The experimental lattice parameter of LiAl x Mn2- x O4 was validated by ab initio calculations and correlated with the first cycle capacity of materials. The variation in lattice parameter as a result of Al doping greatly enhanced the cyclability of discharge capacity of the LiMn2O4 spinel.

  9. 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.

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

    SciTech Connect

    Liang Yanyu; Bao Shujuan; Li Hulin . E-mail: lihl@lzu.edu.cn

    2006-07-15

    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{sup 3+}, F{sup -} 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. - Graphical abstract: It is a SEM image of the spinel LiMn{sub 2}O{sub 4}, which was prepared by this novel hydrothermal procedure. It illustrates that reasonable-crystallized spinel oxide has occurred through the special hydrothermal process and the average particle size declined to about 1 {mu}m. This homogeneous grain size distribution provides an important morphological basis for the reversibility and accessibility of lithium ion insertion/extraction reactions.

  11. Interplay between two-phase and solid solution reactions in high voltage spinel cathode material for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Xiao, Jie; Yu, Xiqian; Zheng, Jianming; Zhou, Yungang; Gao, Fei; Chen, Xilin; Bai, Jianming; Yang, Xiao-Qing; Zhang, Ji-Guang

    2013-11-01

    Lithium ion batteries (LIBs) are attracting intensive interests worldwide because of their potential applications in transportation electrification and utility grid. The intercalation compounds used in LIBs electrochemically react with Li+ ions via single or multiple phase transitions depending on the nature of the material structure as well as the synthesis and operating conditions. For LiNi0.5Mn1.5O4 high voltage spinel, a promising candidate positive electrode material for LIBs, there are three spinel-structured phases sequentially appeared through two successive two-phase reactions during the delithiation/lithiation processes. Here we demonstrate, experimentally and theoretically, that through elemental substitution, the solid solution ranges for both the first and second phases are significantly extended during the electrochemical charge-discharge process. This type of structural changes with more solid solution regions facilitate fast Li+ diffusion by reducing the number of phase boundaries that Li+ ions have to overcome and resulted in less shrinkage of the unit cells at the end of charge process. This work unravels the fundamental interactions between structural and electrochemical properties by using spinel as the platform, which may be widely adopted to explain or tailor the properties of materials for energy storage and conversion.

  12. 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. PMID:26645115

  13. 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.

  14. 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. PMID:27113855

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

    DOE PAGESBeta

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

    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

  16. Interplay between two-phase and solid solution reactions in high voltage spinel cathode material for lithium ion batteries

    SciTech Connect

    Xiao, Jie; Yu, Xiqian; Zheng, Jianming; Zhou, Yungang; Gao, Fei; Chen, Xilin; Bai, Jianming; Yang, Xiao-Qing; Zhang, Jiguang

    2013-06-06

    Lithium ion batteries (LIBs) are attracting intensive interests worldwide because of their potential applications in transportation electrification and utility grid. The intercalation compounds used in LIBs electrochemically react with Li+ ions via single or multiple phase transitions depending on the nature of the material structure as well as the synthesis and testing conditions. It is generally accepted that for high voltage spinel LiNi0.5Mn1.5O4, a promising candidate for LIBs, there are two successive two-phase reactions occurring during the delithiation/lithiation processes, as reflected by the two flat plateaus with a small step in between. Here we demonstrate, experimentally and theoretically, that through elemental substitution, each of the two-phase transitions has been largely converted into a solid solution reaction during the electrochemical process. The latter favors fast Li+ diffusion due to the reduced number of phase boundaries that Li+ ions have to overcome, as well as the reduced shrinkage of unit cells after charge. This work clearly elaborates one of the critical functions for element doping/substitution that has been widely adopted in the materials synthesis for LIBs, whose fundamental mechanisms are still obscured.

  17. Quaternary phase diagrams of spinel Liy□1-yMnxNi2 -xO4 and composite cathode voltages for concentration gradient materials

    NASA Astrophysics Data System (ADS)

    Hao, Shiqiang; Lu, Zhi; Wolverton, Christopher

    2016-07-01

    Core-shell coating structures and concentration gradient materials may enhance Li-ion battery performance by integrating advantages of core and shell components without introducing unfavorable problems associated with general coatings. The fundamental thermodynamic properties of concentration gradient composite materials are complex due to the multicomponent nature of the problem. We systematically study the thermodynamics of ordering and phase separation in the quaternary spinel Liy□1-yMnxNi2 -xO4 (□ means vacancy) system by density functional theory calculations, together with the coupled cluster expansion method with interactions within and between (Li/□) and (Mn/Ni) sublattices. On the basis of coupled cluster expansion interactions and Monte Carlo simulations, we calculate quaternary phase diagrams as a function of temperature as well as voltage profiles of single ordered phases and multiphase composite structures. The phase diagram and voltage results are in good agreement with available experimental observations. We also predict a stable high-voltage ordered compound LiMnNiO4, with a very high delithiation voltage of 4.76 V. For the composite (Mn-rich+Ni -rich) cathode materials, the voltage profiles show combinations of plateaus from each component compound. The computational strategy of combining quaternary phase diagrams with voltage calculations provides a pathway to understand and design concentration gradient materials.

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

    PubMed

    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 Mn(3+) 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

  19. Synthesis of spinel LiNi0.5Mn1.5O4 with secondary plate morphology as cathode material for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Risthaus, Tim; Wang, Jun; Friesen, Alex; Wilken, Andrea; Berghus, Debbie; Winter, Martin; Li, Jie

    2015-10-01

    Spinel LiNi0.5Mn1.5O4 material has been synthesized by a spray drying process and subsequent solid state reaction. Polyvinylpyrrolidone (PVP) is given as additive to the spray drying precursor solution and its effects on structural and electrochemical properties are evaluated. By using PVP in the synthesis process, the obtained sample displays a secondary plate morphology which is consisting of densely arranged primary octahedrally shaped particles. The new cathode material has a lesser degree of impurity phases, a higher discharge capacity, a superior rate capability, and a slightly better cycling performance than the sample synthesized without PVP. In more detail, by the use of PVP the ratio of Mn3+ to Mn4+ in the final product decreases from 20.8 to 9.2%. The initial discharge capacity at 0.1 C exhibits an increase of about 14%. The normalized capacity at 20 C is 84.1% instead of 67.0%. A slightly improved cycling performance with the capacity retention increase from 93.8 to 97.9% could be observed as well.

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

    DOE PAGESBeta

    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 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

  1. 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%.

  2. Ternary Spinel MCo2O4 (M = Mn, Fe, Ni, and Zn) Porous Nanorods as Bifunctional Cathode Materials for Lithium-O2 Batteries.

    PubMed

    Mohamed, Saad Gomaa; Tsai, Yuan-Quei; Chen, Chih-Jung; Tsai, Yi-Ting; Hung, Tai-Feng; Chang, Wen-Sheng; Liu, Ru-Shi

    2015-06-10

    The development of Li-O2 battery electrocatalysts has been extensively explored recently. The Co3O4 oxide has attracted much attention because of its bifunctional activity and high abundance. In the present study, toxic Co(2+) has been replaced through the substitution on the tetrahedral spinel A site ions with environmental friendly metals (Mn(2+), Fe(2+), Ni(2+), and Zn(2+)), and porous nanorod structure are formed. Among these spinel MCo2O4 cathodes, the FeCo2O4 surface has the highest Co(3+) ratio. Thus, oxygen can be easily adsorbed onto the active sites. In addition, Fe(2+) in the tetrahedral site can easily release electrons to reduce oxygen and oxidize to half electron filled Fe(3+). The FeCo2O4 cathode exhibits the highest discharging plateau and lowest charging plateau as shown by the charge-discharge profile. Moreover, the porous FeCo2O4 nanorods can also facilitate achieving high capacity and good cycling performance, which are beneficial for O2 diffusion channels and Li2O2 formation/decomposition pathways. PMID:25984925

  3. 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

  4. 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.

  5. 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.

  6. 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. PMID:26824793

  7. In operando study of the high voltage spinel cathode material LiNi(0.5)Mn(1.5)O4 using two dimensional full-field spectroscopic imaging of Ni and Mn.

    PubMed

    Bauer, Sondes; de Biasi, Lea; Glatthaar, Sven; Toukam, Leonel; Gesswein, Holger; Baumbach, Tilo

    2015-07-01

    LiNi0.5Mn1.5O4 spinel cathode was studied during the first discharge cycle using combined full field Transmission X-ray Microscopy (TXM) and X-ray Absorption Near Edge Structure Spectroscopy (XANES) techniques to follow the chemical phase transformation as well as the microstructural evolution of cathode materials upon operation within an electrochemical cell. The spatial distribution and electrochemical process of the spinel material with spherical granules of 30 μm and 3 μm crystallite size was investigated. The spectroscopic imaging of the cathode within field of view of 40 × 32 μm(2) and spatial resolution of 40 nm has revealed an increase of the LiNi0.5Mn1.5O4 granule size during lithiation providing an insight into the effect of the particle size and morphology on the electrochemical process. The chemical elemental distribution and the content of the different oxidation states of the two absorbing elements (Ni and Mn) have been determined in operando from the XANES imaging. A gradual increase in the content of the oxidation state Mn(3+) from 8% up to 64% has been recorded during the discharge from 5 V to 2.7 V. The study of the local oxidation reduction behavior of Mn(3+) reveals a reversibility aspect in the local electrochemical reaction of Mn(4+) toward Mn(3+) in areas located in the center of the aggregate as well as in areas closed to the electrolyte. During the discharge process, a mixture of Mn(3+) and Mn(4+) has been detected while only single electron valence states have been found in the case of Ni. Probing the chemical changes during the discharge using two-dimensional XANES reveals spatial differences in the electrochemical activities of the two absorbing elements Ni and Mn. PMID:26051380

  8. Copper cobalt spinel as a high performance cathode for intermediate temperature solid oxide fuel cells.

    PubMed

    Shao, Lin; Wang, Qi; Fan, Lishuang; Wang, Pengxiang; Zhang, Naiqing; Sun, Kening

    2016-06-30

    CuCo2O4 spinel prepared via an EDTA-citric acid process was studied as a candidate solid oxide fuel cell (SOFC) cathode material at intermediate temperatures (IT). CuCo2O4 cathodes were measured using thermal gravimetric analysis, X-ray diffraction and scanning electron microscopy. AC impedance spectroscopy and DC polarization measurements were used to study the electrode performance. The obtained value of the polarization resistances at 800 °C was 0.12 Ω cm(2) with a maximum power density of 972 mW cm(-2). PMID:27326915

  9. 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.

  10. 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.

  11. 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

  12. 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. PMID:23237664

  13. 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

    2016-09-01

    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. PMID:27530465

  14. 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

  15. 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.

  16. 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.

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

    DOE PAGESBeta

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

    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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

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

    PubMed

    Bhattacharya, Jishnu; Wolverton, C

    2013-05-01

    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. PMID:23529669

  3. 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.

  4. 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. PMID:26807506

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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. PMID:21944282

  11. Phthalocyanine cathode materials for secondary lithium cells

    SciTech Connect

    Tamaki, J.; Yamaji, A.

    1982-01-01

    Discharge and charge characteristics of various phthalocyanine cathodes coupled with lithium metal are studied. The best capacity based only on cathode active material weight is 1440 A-hr/kg in the lithium/iron phthalocyanine system, and the cycle life of the lithium/Cu phthalocyanine system is more than 100 times at the discharge depth of 157 A-hr/kg. The cathode reaction mechanism is supposed to be lithium intercalation between phthalocyanine molecules. The results indicate that these phthalocyanines are promising cathode active materials for lithium secondary batteries.

  12. 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}.

  13. 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.

  14. 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.

  15. 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.

  16. Composite and diamond cold cathode materials

    SciTech Connect

    Worthington, M.S.; Wheeland, C.L.; Ramacher, K.; Doyle, E.

    1996-12-31

    Cold-cathode technology for Crossed-Field Amplifiers (CFAs) has not changed significantly over the last thirty years. The material typically used for cold cathode CFAs is either platinum (Pt) or beryllium (Be), although numerous other materials with higher secondary electron emission ratios have been tested. Beryllium cathodes display higher secondary emission ratios, {approximately} 3.4, than Pt, but require a partial pressure of oxygen to maintain a beryllium oxide (BeO) surface layer. These dispensers limit the life of the CFA, both directly, due to oxygen-source filament burnout, and indirectly, by the production of undesirable gases which adversely affect the performance of the CFA. In an attempt to reduce or eliminate the required oxygen dispenser output level, cathodes were constructed from three varieties of Be/BeO composite material and tested in L-4808s, standard forward-wave AEGIS CFAs. Diamond and diamond-like carbons are desirable as cathode materials because of their extremely high secondary electron emission ratio, greater than 20, but their use has previously been prohibitive because of cost, available, and physical characteristics. Because of recent advances in diamond growth technology it is now possible to deposit thin layers of diamond on a variety of geometric objects. In coordination with Penn State University four annular diamond emitters have been fabricated. The diamond emitters will be tested in a standard AEGIS CFA, both under vacuum and with a partial pressure of hydrogen.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. Deciphering the thermal behavior of lithium rich cathode material by in situ X-ray diffraction technique

    NASA Astrophysics Data System (ADS)

    Muhammad, Shoaib; Lee, Sangwoo; Kim, Hyunchul; Yoon, Jeongbae; Jang, Donghyuk; Yoon, Jaegu; Park, Jin-Hwan; Yoon, Won-Sub

    2015-07-01

    Thermal stability is one of the critical requirements for commercial operation of high energy lithium-ion batteries. In this study, we use in situ X-ray diffraction technique to elucidate the thermal degradation mechanism of 0.5Li2MnO3-0.5LiNi0.33Co0.33Mn0.33O2 lithium rich cathode material in the absence and presence of electrolyte to simulate the real life battery conditions and compare its thermal behavior with the commercial LiNi0.33Co0.33Mn0.33O2 cathode material. We show that the thermal induced phase transformations in delithiated lithium rich cathode material are much more intense compared to similar single phase layered cathode material in the presence of electrolyte. The structural changes in both cathode materials with the temperature rise follow different trends in the absence and presence of electrolyte between 25 and 600 °C. Phase transitions are comparatively simple in the absence of electrolyte, the fully charged lithium rich cathode material demonstrates better thermal stability by maintaining its phase till 379 °C, and afterwards spinel structure is formed. In the presence of electrolyte, however, the spinel structure appears at 207 °C, subsequently it transforms to rock salt type cubic phase at 425 °C with additional metallic, metal fluoride, and metal carbonate phases.

  2. 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}.

  3. 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

  4. 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.

  5. 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.

  6. Role of morphology in the performance of LiFe0.5Mn1.5O4 spinel cathodes for lithium-ion batteries.

    PubMed

    Pico, M P; Álvarez-Serrano, I; López, M L; Veiga, M L

    2014-10-21

    Spinel oxides with composition LiMn2-xMxO4 (M, a transition metal) are intensively studied due to their remarkable electrochemical properties. This study deals with cathode materials based on the lithium iron manganese oxide LiFe0.5Mn1.5O4 synthesized by different methods (sol-gel, in solution and hydrothermal) in order to obtain samples with various morphologies. SEM results show microspheres, composed of nanosized/submicrometer-sized subunits, microrods with a less porous surface, and finally nanoparticles that form micro-sized aggregates. The samples obtained by both solution and hydrothermal methods provided the best electrochemical behavior. In all cases, the coulombic efficiency is around 90%, and it remains constant during the tested cycles. Specific capacities remain stable between 95% and 98% of capacity retention after series of cycles in samples formed by microspheres or micro-size aggregates. These values are notably higher than those obtained for the samples with particles of heterogeneous size (49%). A LiMn1.5Fe0.5O4/Li2MnO3 composite has been prepared by the solvothermal technique in order to increase its capacity and energy density. These cells show a good cyclability at different current densities. All cells based on these LiFe0.5Mn1.5O4 cathodes recover their discharge capacity when the current density returns to C/10. PMID:25160729

  7. 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.

  8. 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.

  9. 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.

  10. 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. PMID:25407246

  11. Chemical, structural, and electrochemical characterization of 5 V spinel and complex layered oxide cathodes of lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Tiruvannamalai Annamalai, Arun Kumar

    2007-12-01

    Lithium ion batteries have revolutionized the portable electronics market since their commercialization first by Sony Corporation in 1990. They are also being intensively pursued for electric and hybrid electric vehicle applications. Commercial lithium ion cells are currently made largely with the layered LiCoO 2 cathode. However, only 50% of the theoretical capacity of LiCoO 2 can be utilized in practical cells due to the chemical and structural instabilities at deep charge as well as safety concerns. These drawbacks together with the high cost and toxicity of Co have created enormous interest in alternative cathodes. In this regard, spinel LiMn2O4 has been investigated widely as Mn is inexpensive and environmentally benign. However, LiMn 2O4 exhibits severe capacity fade on cycling, particularly at elevated temperatures. With an aim to overcome the capacity fading problems, several cationic substitutions to give LiMn2-yMyO 4 (M = Cr, Fe, Co, Ni, and Cu) have been pursued in the literature. Among the cation-substituted systems, LiMn1.5Ni0.5O 4 has become attractive as it shows a high capacity of ˜ 130 mAh/g (theoretical capacity: 147 mAh/g) at around 4.7 V. With an aim to improve the electrochemical performance of the 5 V LiMn 1.5Ni0.5O4 spinel oxide, various cation-substituted LiMn1.5-yNi0.5-zMy+zO4 (M = Li, Mg, Fe, Co, and Zn) spinel oxides have been investigated by chemical lithium extraction. The cation-substituted LiMn1.5-yNi0.5-zM y+zO4 spinel oxides exhibit better cyclability and rate capability in the 5 V region compared to the unsubstituted LiMn1.5Ni 0.5O4 cathodes although the degree of manganese dissolution does not vary significantly. The better electrochemical properties of LiMn 1.5-yNi0.5-zMy+zO4 are found to be due to a smaller lattice parameter difference among the three cubic phases formed during the charge-discharge process. In addition, while the spinel Li1-xMn1.58Ni0.42O4 was chemically stable, the spinel Li1-xCo2O4 was found to exhibit both

  12. 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.

  13. 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.

  14. 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. PMID:25402183

  15. Lithium and sodium battery cathode materials: computational insights into voltage, diffusion and nanostructural properties.

    PubMed

    Islam, M Saiful; Fisher, Craig A J

    2014-01-01

    Energy storage technologies are critical in addressing the global challenge of clean sustainable energy. Major advances in rechargeable batteries for portable electronics, electric vehicles and large-scale grid storage will depend on the discovery and exploitation of new high performance materials, which requires a greater fundamental understanding of their properties on the atomic and nanoscopic scales. This review describes some of the exciting progress being made in this area through use of computer simulation techniques, focusing primarily on positive electrode (cathode) materials for lithium-ion batteries, but also including a timely overview of the growing area of new cathode materials for sodium-ion batteries. In general, two main types of technique have been employed, namely electronic structure methods based on density functional theory, and atomistic potentials-based methods. A major theme of much computational work has been the significant synergy with experimental studies. The scope of contemporary work is highlighted by studies of a broad range of topical materials encompassing layered, spinel and polyanionic framework compounds such as LiCoO2, LiMn2O4 and LiFePO4 respectively. Fundamental features important to cathode performance are examined, including voltage trends, ion diffusion paths and dimensionalities, intrinsic defect chemistry, and surface properties of nanostructures. PMID:24202440

  16. The dependence of vircator oscillation mode on cathode material

    NASA Astrophysics Data System (ADS)

    Li, Limin; Liu, Lie; Cheng, Guoxin; Xu, Qifu; Wan, Hong; Chang, Lei; Wen, Jianchun

    2009-06-01

    This paper presents the effects of cathode materials on the oscillation mode of a virtual cathode oscillator (vircator). In the case of the stainless steel cathode, an oscillation mode hopping appeared with two separate frequencies. Interestingly, the vircator using the carbon fiber cathode exhibited an almost unchanged microwave frequency throughout the microwave pulse. To understand this phenomenon, several parameters are compared, including the diode voltage, accelerating gap, emitting area, and beam uniformity. It was found that a flat-top voltage and a relatively stable gap will provide a possibility of generating a constant microwave frequency. Further, the cathode operated in a regime where the beam current was between the space-charge limited current determined by Child-Langmuir law and the bipolar flow. On the cathode surface, the electron emission is initiated from discrete plasma spots and next from a continuing area, while there is a liberation process of multilayer gases on the anode surface. The changes in the emitting area of carbon fiber cathode showed a self-quenching process, which is not observed in the case of stainless steel cathode. The two-dimensional effect of microwave frequency is introduced, and the obtained results supported the experimental observations on the oscillation mode. By examining the cross section of electron beam, the electron beam for carbon fiber cathode was significantly centralized, while the discrete beam spots appeared for stainless steel cathode. These results show that the slowed diode closure, high emission uniformity, and stable microwave frequency tend to be closely tied.

  17. 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. PMID:26250701

  18. 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.

  19. 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.

  20. Two-step oxalate approach for the preparation of high performance LiNi0.5Mn1.5O4 cathode material with high voltage

    NASA Astrophysics Data System (ADS)

    Liu, Zushan; Jiang, Yangmei; Zeng, Xiaoyuan; Xiao, Guan; Song, Huiyu; Liao, Shijun

    2014-02-01

    A high voltage cathode material, LiNi0.5Mn1.5O4, is synthesized with a two-step approach, in which the nickel-manganese oxalate precipitate is firstly obtained by adding oxalic acid to the solution of nickel and manganese ions precursors, followed by calcining the oxalates to obtain spinel nickel-manganese oxide, incorporating lithium ions with ball milling and calcining at 900 °C for 15 h. The materials are characterized with TG, XRD, SEM, BET and FTIR; it is revealed that both nickel-manganese oxide and final LiNi0.5Mn1.5O4 have well defined spinel structure. The LiNi0.5Mn1.5O4 spinel materials exhibit high capacities and good cyclic stability, the capacity of the materials is in the range from 126 to 136 mAh -1, depending on the calcining temperatures. The sample calcined at an optimal temperature of 900 °C exhibits best performance, the capacity is high up to 136 mAh g-1 at tenth cycle and the capacity retention after 50 cycles is 93%. For the sample prepared by mixing and milling oxalate with lithium salt, the discharge capacity is only 115 mAh g-1. We suggest that the spinel oxide derived from oxalate may play an important role for the high performance and high stability of the final cathode materials.

  1. 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. PMID:26799282

  2. 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

  3. 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. PMID:25610630

  4. 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. PMID:26112347

  5. 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.

  6. A SYSTEMATIC STUDY OF INTERCALATION COMPOUNDS AS CATHODE MATERIALS FOR LITHIUM BATTERIES.

    SciTech Connect

    YANG,X.Q.; MCBREEN,J.

    2001-06-08

    Three types of intercalation Compounds, LiMn{sub 2}O{sub 4} with spinel structure, LiNiO{sub 2} and LiCoO{sub 2} with layered structure are widely studied as cathode materials for lithium-ion batteries. Among them, LiCoO{sub 2} is the most widely used cathode material in commercial lithium battery cells. LiNiO{sub 2} has same theoretical capacity as LiCoO{sub 2}, but is less expensive. However its application in lithium batteries has not been realized due to serious safety concerns. Substituting a portion of Ni in LiNiO{sub 2} with other cations has been pursued as a way to improve its safety characteristics. It was reported that Co doped LiNi{sub 0.8}Co{sub 0.2}O{sub 2} showed better thermal stability than pure LiNiO{sub 2}. Many new materials have been developed aimed in increasing the capacity and improving the thermal stability and cyclability. Most of these new materials are based on these three types of materials and modified their compositions and structures by doping. However, most of the efforts on developing new cathode materials have been done on the empirical base without guidelines from the systematic studies on the relationship between the performance and the structural changes of the cathode materials. Exploring this relationship is very important not only in guiding the development of new materials, but also in improving the performance and safety aspect for the existing cathode materials for lithium ion batteries. Using conventional x-ray source and a specially designed battery cell with beryllium windows, Dahn and co-workers have published several papers on the structural changes of LiNiO{sub 2} cathodes 1 and LiCoO{sub 2} cathodes 2 during charge. Unfortunately, the charging voltage was limited to below 4.3 V due to the problem of beryllium window corrosion at higher voltage. However, the voltage range between 4.3 V and 5.2 V is the most important region for studying the relationship between the thermal stability and structural changes during

  7. Durability and performance optimization of cathode materials for fuel cells

    NASA Astrophysics Data System (ADS)

    Colon-Mercado, Hector Rafael

    The primary objective of this dissertation is to develop an accelerated durability test (ADT) for the evaluation of cathode materials for fuel cells. The work has been divided in two main categories, namely high temperature fuel cells with emphasis on the Molten Carbonate Fuel Cell (MCFC) cathode current collector corrosion problems and low temperature fuel cells in particular Polymer Electrolyte Fuel Cell (PEMFC) cathode catalyst corrosion. The high operating temperature of MCFC has given it benefits over other fuel cells. These include higher efficiencies (>50%), faster electrode kinetics, etc. At 650°C, the theoretical open circuit voltage is established, providing low electrode overpotentials without requiring any noble metal catalysts and permitting high electrochemical efficiency. The waste heat is generated at sufficiently high temperatures to make it useful as a co-product. However, in order to commercialize the MCFC, a lifetime of 40,000 hours of operation must be achieved. The major limiting factor in the MCFC is the corrosion of cathode materials, which include cathode electrode and cathode current collector. In the first part of this dissertation the corrosion characteristics of bare, heat-treated and cobalt coated titanium alloys were studied using an ADT and compared with that of state of the art current collector material, SS 316. PEMFCs are the best choice for a wide range of portable, stationary and automotive applications because of their high power density and relatively low-temperature operation. However, a major impediment in the commercialization of the fuel cell technology is the cost involved due to the large amount of platinum electrocatalyst used in the cathode catalyst. In an effort to increase the power and decrease the cathode cost in polymer electrolyte fuel cell (PEMFC) systems, Pt-alloy catalysts were developed to increase its activity and stability. Extensive research has been conducted in the area of new alloy development and

  8. Understanding the Origin of Enhanced Performances in Core-Shell and Concentration-Gradient Layered Oxide Cathode Materials.

    PubMed

    Song, Dawei; Hou, Peiyu; Wang, Xiaoqing; Shi, Xixi; Zhang, Lianqi

    2015-06-17

    Core-shell and concentration-gradient layered oxide cathode materials deliver superior electrochemical properties such as long cycle life and outstanding thermal stability. However, the origin of enhanced performance is not clear and seldom investigated until now. Here, a specific structured layered oxide (LiNi0.5Co0.2Mn0.3O2) consisting of concentration-gradient core, transition layer, and stable outer shell, is designed and achieved from double-shelled precursors to overcome the great challenge by comparison with the normal layered LiNi0.5Co0.2Mn0.3O2. As expected, the specific structured layered oxide displays excellent cycle life and thermal stability. After numerous cycles, the valence state of Ni and Co at normal layered oxide surface tends to a higher oxidation state than that of the specific structured oxide, and the spinel phase is observed on particle surface of normal layered oxide. Also, the deficient spinel/layered mixed phases lead to high surface film and charge-transfer resistance for normal layered oxide, whereas the specific structured one still remains a layered structure. Those results first illustrate the origin of improved electrochemical performance of layered core-shell and concentration-gradient cathode materials for lithium-ion batteries. PMID:26017733

  9. 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.

  10. Refractory Materials based on Magnesia-Alumina Spinel for Improved Performance in Coal Gasification Environments

    SciTech Connect

    Hemrick, James Gordon; Armstrong, Beth L; Rodrigues-Schroer, Angela; Colavito,; Smith, Jeffrey D; O'Hara, Kelley

    2013-01-01

    As part of a larger project to develop novel refractory systems and techniques to reduce energy consumption of refractory lined vessels, a team composed of Oak Ridge National Laboratory, refractory manufacturer Minteq International, Inc., and academic partner Missouri University of Science and Technology have developed new refractory materials and coating systems specifically for application in coal gasification environments. Materials were developed under this U.S. DOE funded project to address the need for innovative refractory compositions by developing MgO-Al2O3 spinel gunnable refractory compositions utilizing new aggregate materials, bond systems, protective coatings, and phase formation techniques. Work was conducted to develop and deploy these new materials and to develop and apply low cost coatings using a colloidal approach for protection against attack of the refractory brick by the serviced environment. Additionally, a light-weight back-up refractory system was developed to help offset the high thermal conductivity inherent in spinel materials. This paper discusses the efforts involved in the development of these materials, along with the laboratory testing and evaluation of these materials leading to relevant results achieved toward the reduction of chemical reactions and mechanical degradation by the service environment though compositional and processing modifications.

  11. 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. PMID:24503944

  12. Why is magnesia spinel a radiation-resistant material?

    NASA Astrophysics Data System (ADS)

    Kinoshita, C.; Fukumoto, K.; Fukuda, K.; Garner, F. A.; Hollenberg, G. W.

    1995-03-01

    Side-by-side irradiation of stoichiometric MgAl 2O 4 and α-Al 2O 3 in JOYO shows that the radiation-induced microstructural evolution to exposure of ≤ 6 dpa proceeds by very different paths in these two materials. The large difference in dislocation loop evolution appears to account for the ease of void swelling in α-Al 2O 3 and the strong resistance to void formation in MgAl 2O 4. Irradiation of MgAl 2O 4 to much higher exposure (22-230 dpa) in FFTF confirms the details of the dislocation evolution, which involves a progressive change in Burgers vector and habit plane as interstitial loops increase in size. Constraints unique to the MgAl 2O 4 crystal structure do not allow the formation of dislocation network structures that favor swelling.

  13. 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.

  14. In Situ X-ray Diffraction Studies of Li(sub x)Mn(sub 2)O(sub 4) Cathode Materials by Synchrotron X-ray Radiation

    SciTech Connect

    Yang, X. Q.; Sun, X.; Lee, S. J.; McBreen, J.; Mukerjee, S.; Daroux, M. L.; Xing, X. K.

    1998-11-01

    In Situ x-ray diffraction studies on Li{sub x}Mn{sub 2}O{sub 4} spinel cathode materials during charge-discharge cycles were carried out by using a synchrotron as x-ray source. Lithium rich (x = 1.03-1.06) spinel materials obtained from two different sources were studied. Three cubic phases with different lattice constants were observed during charge-discharge cycles in all the samples when a Sufficiently low charge-discharge rate (C/10) was used. There are two regions of two-phase coexistence between these three phases, indicating that both phase transitions are first order. The separation of the Bragg peaks representing these three phases varies from sample to sample and also depends on the charge-discharge rate. These results show that the de-intercalation of lithium in lithium-rich spinel cathode materials proceeds through a series of phase transitions from a lithium-rich phase to a lithium-poor phase and finally to a {lambda}-MnO{sub 2} like cubic phase, rather than through a continuous lattice constant contraction in a single phase.

  15. 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.

  16. 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

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

    SciTech Connect

    Allan J. Jacobson

    2005-11-17

    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, the oxygen exchange kinetics of a P2 composition are described in detail. The oxygen exchange kinetics of the oxygen deficient double perovskite LnBaCo{sub 2}O{sub 5.5+{delta}} (Ln=Pr and Nd) have been determined by electrical conductivity relaxation. 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.

  18. Structural changes and thermal stability of charged LiNi 1/3Co 1/3Mn 1/3O 2 cathode material for Li-ion batteries studied by time-resolved XRD

    NASA Astrophysics Data System (ADS)

    Nam, Kyung-Wan; Yoon, Won-Sub; Yang, Xiao-Qing

    Structural changes and their relationship with thermal stability of charged Li 0.33Ni 1/3Co 1/3Mn 1/3O 2 cathode samples have been studied using time-resolved X-ray diffraction (TR-XRD) in a wide temperature from 25 to 600 °C with and without the presence of electrolyte in comparison with Li 0.27Ni 0.8Co 0.15Al 0.05O 2 cathodes. Unique phase transition behavior during heating is found for the Li 0.33Ni 1/3Co 1/3Mn 1/3O 2 cathode samples: when no electrolyte is present, the initial layered structure changes first to a LiM 2O 4-type spinel, and then to a M 3O 4-type spinel and remains in this structure up to 600 °C. For the Li 0.33Ni 1/3Co 1/3Mn 1/3O 2 cathode sample with electrolyte, additional phase transition from the M 3O 4-type spinel to the MO-type rock salt phase takes place from about 400 to 441 °C together with the formation of metallic phase at about 460 °C. The major difference between this type of phase transitions and that for Li 0.27Ni 0.8Co 0.15Al 0.05O 2 in the presence of electrolyte is the delayed phase transition from the spinel-type to the rock salt-type phase by stretching the temperature range of spinel phases from about 20 to 140 °C. This unique behavior is considered as the key factor of the better thermal stability of the Li 1-xNi 1/3Co 1/3Mn 1/3O 2 cathode materials.

  19. Cathode materials for the molten carbonate fuel cell

    SciTech Connect

    Kucera, G.H.; Brown, A.P.; Roche, M.F.; Indacochea, E.J.; Krumpelt, M.; Myles, K.M.

    1993-08-01

    Both LiFeO{sub 2} and Li{sub 2},MnO{sub 3} were stable in the cathode environment, had low solubility, and were nonprecipitating in the anode environment. Dopants were employed to enhance the electronic conductivity of both materials. Cobalt-doped LiFeO{sub 2} was a factor of 30 more conductive than the undoped LiFeO{sub 2}; Nb-doped Li{sub 2}MnO{sub 3} was a factor of 60 more conductive than its undoped form. However, only the Co-doped LiFeO{sub 2} Li{sub 2} exhibited the desired p-type conduction. Half- and full-cell tests with Co-doped LiFeO{sub 2} as the cathode material showed that its performance strongly depended on the oxygen partial pressure. Under simulated high-pressure conditions, where the O{sub 2} partial pressure was 70 kPa, the performance was good. LiCoO{sub 2} had low solubility and was a good electronic conductor undoped. In addition, it exhibited p-type conduction, and, when used as a cathode material, gave good cell performance. It precipitated as cobalt metal under reducing conditions in anode. However, neither rate of deposition nor conditions influencing deposition and location are known.

  20. 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.

  1. 1-Nitronapthalene as a cathode material for magnesium reserve batteries

    NASA Astrophysics Data System (ADS)

    Thirunakaran, R.; Vasudevan, S.; Sivashanmugam, A.; Kumar, Gopu; Muniyandi, N.

    1-Nitronaphthalene has been investigated for use as a battery depolarizer in conjunction with a high-energt magnesium anode. Acetylene black is added to improve the conductivity of the non-conducting organic compound and its concentration in the mix is optimized for better performance of the cathode. To assess its suitability and its characteristics as a cathode active material, magnesium/1-nitronaphthalene cells are fabricated and discharged in different electrolytes (magnesium chloride, magnesium bromide and magnesium perchlorate) at various current densities. The capacity delivered by the cell system shows better reduction efficiency of the 1-nitronaphthalene depolarizer. Cyclic voltammetric studies are carried out on a glassy-carbon electrode to understand the reduction behaviour of 1-nitronaphthalene.

  2. First principle computational and experimental studies of cathode materials for lithium ion rechargeable batteries

    NASA Astrophysics Data System (ADS)

    Saavedra Arias, Jose Javier

    We have studied the properties of spinel and layered cathode materials for Li ion rechargeable batteries. The analysis was done by first principle calculations, and experimental techniques to elucidate materials that can substitute the presently commercialized material, namely LiCoO 2. We have studied the influence of Ni substitution for Mn in spinel Li 2MnO4. To understand the effects of this substitution on the crystal structure and electronic properties, first principle DFT calculations were performed using VASP. The substitution was done systematically for up to 25% of Mn replacement by Ni in a super cell configuration. Furthermore, the influence of Ni substitution on lithium hoping pathways between the two stable Li positions was also studied by first principle calculations in LiMn 2-xNixO4. These calculations revealed that Ni substitution for Mn in LiMn2O4 indeed improved Li ion mobility. Thereafter, systematic experimental studies were performed on LiMn 2-xNixO4 (0materials were synthesized by solution route and their structural characterization was done using X-ray diffraction (XRD) and Raman spectroscopy. The electrochemical performance of LiMn2-xNi xO4 materials was evaluated in two electrode CR2032 type coin cell configuration with Li metal as anode and liquid electrolyte (1 M LiPF6 in EC:DMC=1:1 v/v). Our results showed significant enhancement in the electrochemical properties with 25% of Ni substitution in LiMn 2O4, which is in good agreement with the theoretical calculations. We also studied layered cathode materials both theoretically and experimentally. The First principle calculations in conjunction with alloy metal method were used to evaluate the average voltage and phase stability of LiMO2 (M=Co, Ni, Mn, W) systems. By formation energy analysis we established that LiNi0.8Co0.1Mn0.1O2 is a promising candidate cathode material. Single

  3. 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.

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

    DOE PAGESBeta

    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 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

  5. High voltage spinel oxides for Li-ion batteries: From the material research to the application

    NASA Astrophysics Data System (ADS)

    Patoux, Sébastien; Daniel, Lise; Bourbon, Carole; Lignier, Hélène; Pagano, Carole; Le Cras, Frédéric; Jouanneau, Séverine; Martinet, Sébastien

    Li-ion batteries are already used in many nomad applications, but improvement of this technology is still necessary to be durably introduced on new markets such as electric vehicles (EVs), hybrid electric vehicles (HEVs) or eventually photovoltaic solar cells. Modification of the nature of the active materials of electrodes is the most challenging and innovative aspect. High voltage spinel oxides for Li-ion batteries, with general composition LiMn 2- xM xO 4 (M a transition metal element), may be used to face increasing power source demand. It should be possible to obtain up to 240 Wh kg -1 at cell level when combining a nickel manganese spinel oxide with graphite (even more with silicon/carbon nanocomposites at the anode). Specific composition and material processing have to be selected with care, as discussed in this paper. It is demonstrated that 'LiNi 0.5Mn 1.5O 4' and LiNi 0.4Mn 1.6O 4 have remarkable properties such as high potential, high energy density, good cycle life and high rate capability. Choice of the electrolyte is also of primary importance in order to prevent its degradation at high voltage in contact with active surfaces. We showed that a few percents of additive in the electrolyte were suitable for protecting the positive electrode/electrolyte interface, and reducing the self-discharge. High voltage materials are also possibly interesting to be used in safe and high power Li-ion cells. In this case, the negative electrode may be made of Li 4Ti 5O 12 or TiO 2 to give a '3 V' system.

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

    DOEpatents

    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.

  7. 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.

  8. Understanding Voltage Decay in Lithium-Rich Manganese-Based Layered Cathode Materials by Limiting Cutoff Voltage.

    PubMed

    Yang, Jingsong; Xiao, Lifen; He, Wei; Fan, Jiangwei; Chen, Zhongxue; Ai, Xinping; Yang, Hanxi; Cao, Yuliang

    2016-07-27

    The effect of the cutoff voltages on the working voltage decay and cyclability of the lithium-rich manganese-based layered cathode (LRMO) was investigated by electrochemical measurements, electrochemical impedance spectroscopy, ex situ X-ray diffraction, transmission electron microscopy, and energy dispersive spectroscopy line scan technologies. It was found that both lower (2.0 V) and upper (4.8 V) cutoff voltages cause severe voltage decay with cycling due to formation of the spinel phase and migration of the transition metals inside the particles. Appropriate cutoff voltage between 2.8 and 4.4 V can effectively inhibit structural variation as the electrode demonstrates 92% capacity retention and indiscernible working voltage decay over 430 cycles. The results also show that phase transformation not only on high charge voltage but also on low discharge voltage should be addressed to obtain highly stable LRMO materials. PMID:27383918

  9. 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.

  10. 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.

  11. Advanced hybrid battery with a magnesium metal anode and a spinel LiMn2O4 cathode.

    PubMed

    Pan, Baofei; Feng, Zhenxing; Sa, Niya; Han, Sang-Don; Ma, Qing; Fenter, Paul; Vaughey, John T; Zhang, Zhengcheng; Liao, Chen

    2016-08-01

    Two Mg-Li dual salt hybrid electrolytes are developed, which exhibit excellent oxidative stability up to around 3.8 V (vs. Mg/Mg(2+)) on an aluminum current collector, enabling the successful coupling of several state-of-the-art lithium-ion intercalation cathodes (LiMn2O4, LiCoO2 and LiNi1/3Mn1/3Co1/3O2) with magnesium metal anodes. The Mg-LiMn2O4 battery delivers an initial discharge capacity of about 106 mA h g(-1) with a working voltage of around 2.8 V (vs. Mg/Mg(2+)), highlighting the highest working voltage of rechargeable batteries with magnesium metal anodes to date. PMID:27439946

  12. 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.

  13. 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

  14. Alternate anode materials for cathodic protection of steel reinforced concrete

    SciTech Connect

    Russell, James H.; Bullard, Sophie J.; Covino, Bernard S., Jr.; Cramer, Stephen D.; Holcomb, Gordon R.; Cryer, Curtis B.

    2001-01-01

    Consumable and non-consumable anodes were evaluated in the laboratory for use in cathodic protection (CP) systems for steel reinforced concrete bridges in coastal environments and in areas where deicing salts are employed. The anode materials included Zn-hydrogel and thermal-sprayed Zn, Zn-15Al, Al-12Zn-0.2In, and cobalt-sprayed Ti. These anodes were evaluated for service in both galvanic (GCP) and impressed current (ICCP) cathodic protection systems. Impressed current CP anodes were electrochemically aged at a current density 15 times as great as that used by the Oregon Department of Transportation in typical coastal ICCP systems (2.2 mA/m2 based on anode area). Increasing moisture at the anode-concrete interface reduced the operating voltage of all the anodes. Bond strength between the anodes and concrete decreased with electrochemical aging. The Zn-15Al and Al-12Zn-0.2In anodes provided adequate protection in GCP but their life was too short in the accelerated ICCP tests. Zinc had an adequate life in ICCP tests but was inadequate as a galvanic anode. Zinc-hydrogel performed well in both tests when the hydrogel was kept moist. Titanium was an excellent anode for ICCP, but is not suitable for GCP.

  15. 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

  16. 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.

  17. Nickel hydroxide and other nanophase cathode materials for rechargeable batteries

    NASA Astrophysics Data System (ADS)

    Reisner, David E.; Salkind, Alvin J.; Strutt, Peter R.; Xiao, T. Danny

    The staff of US Nanocorp, Inc. are developing unique nanostructured materials for a wide range of applications in the areas of energy storage (batteries and ultracapacitors) and energy conversion (fuel cells and thermoelectric) devices. Many of the preparations of these materials exploit a wet synthesis process (patent pending) that is scaleable to large volume manufacturing and anticipated to be low in cost. Specifically, both the β-form of nickel hydroxide and the hollandite form of manganese dioxide have been synthesized. The hexagonal Ni(OH) 2 is anticipated to significantly boost energy densities in nickel-alkaline batteries, including nickel/cadmium, nickel/metal hydride and nickel/zinc. The nanophase MnO 2 microstructure exhibits an unusual tunnelled tubular geometry within a 'bird's nest' superstructure, and is expected to be of interest as an intercalation cathode material in lithium-ion systems as well as a catalyst for fuel cells. Characterization of these materials has been by the techniques of high resolution SEM and TEM, as well as XRD. Both Hg porosimetry and BET surface measurements for conventional and spherical nickel hydroxides are summarized. Pore distribution and electrochemical activity for the nanophase materials will be examined in the future.

  18. Cobalt Hexacyanoferrate as Cathode Material for Na+ Secondary Battery

    NASA Astrophysics Data System (ADS)

    Takachi, Masamitsu; Matsuda, Tomoyuki; Moritomo, Yutaka

    2013-02-01

    We investigated structural and electrochemical properties of thin film electrodes of cobalt hexacyanoferrate, NaxCo[Fe(CN)6]0.902.9H2O, against x. The compound exhibits a high capacity of 135 mAh/g and an average operating voltage of 3.6 V against Na, with a good cyclability. The discharge curve exhibits two plateaus at ≈3.8 and ≈3.4 V, which are ascribed to the reduction processes of Fe3+ and Co3+, respectively. The ex situ X-ray diffraction (XRD) profiles reveal the robust nature of the host framework against Na+ intercalation/deintercalation. Thus, cobalt hexacyanoferrate is a promising candidate for the cathode material of sodium-ion secondary battery (SIB).

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. Synthesis and electrochemical characterizations of nano-La{sub 2}O{sub 3}-coated nanostructure LiMn{sub 2}O{sub 4} cathode materials for rechargeable lithium batteries

    SciTech Connect

    Arumugam, D.; Paruthimal Kalaignan, G.

    2010-12-15

    LiMn{sub 2}O{sub 4} spinel cathode materials were coated with 1.0, 2.0 and 3.0 wt.% of La{sub 2}O{sub 3} by polymeric process, followed by calcinations at 850 {sup o}C for 6 h in air. The surface coated LiMn{sub 2}O{sub 4} cathode materials were physically characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and XPS. XRD patterns of La{sub 2}O{sub 3}-coated LiMn{sub 2}O{sub 4} revealed that the coating did not affect the crystal structure and space group Fd3m of the cathode materials, compared to the uncoated LiMn{sub 2}O{sub 4}. The surface morphology and particle agglomeration were investigated using scanning electron microscopy and the TEM image showed a compact coating layer on the surface of the core materials that had average thickness of about 100 nm. XPS data illustrated that the La{sub 2}O{sub 3} was completely coated over the surface of the LiMn{sub 2}O{sub 4} core cathode materials. The galvanostatic charge and discharge of the uncoated and La{sub 2}O{sub 3}-coated LiMn{sub 2}O{sub 4} cathode materials were carried out in the potential range of 3.0 and 4.5 V at 30 {sup o}C and 60 {sup o}C. Among them, 2.0 wt.% of La{sub 2}O{sub 3}-coated spinel LiMn{sub 2}O{sub 4} cathode has improved the structural stability, high reversible capacity and excellent electrochemical performances of the rechargeable lithium batteries.

  4. Modified nickel oxides as cathode materials for MCFC

    NASA Astrophysics Data System (ADS)

    Daza, L.; Rangel, C. M.; Baranda, J.; Casais, M. T.; Martínez, M. J.; Alonso, J. A.

    The preparation and subsequent oxidation of nickel cathodes modified by impregnation with cerium were evaluated by surface and bulk analysis. The cerium impregnated cathodes showed the same pore size distribution curve types and the same morphology as the reference nickel cathode. The measured nickel oxide dissolution rate in the molten carbonate mixture indicated that a minimum corrosion was evident for cathodes with 0.3-1 wt.% cerium oxide content. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed in the cathode characterization. As can be seen by SEM, the corrosion treatments produce marked modifications on the sample surfaces that appear more prominent for the cerium-free sample. The results also show that the lithiation process is a very significant factor that can improve the efficiency of the cell, but needs to be controlled because it can also produce very damaging effects such as the modification of the cathode volume by the formation on new compounds.

  5. 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. PMID:26761603

  6. Synthesis, Characterization and Electrochemical Analysis of Composite Cathode Material 0.5Li2MnO3-0.25LiMn2O4-0.25LiNi0.5Mn0.5O2 for LIB applications

    NASA Astrophysics Data System (ADS)

    Lopez de Victoria, Monica; Shojan, Jifi; Torres, Loraine; Katiyar, Rajesh; Dorvilien, Valerio; Katiyar, Ram

    Structural stability, environment friendliness, low cost as well as good electrochemical performances are the major requirements for cathode materials. Li2MnO3 based composite cathode materials are one of the widely investigated positive cathode materials due to their ability to provide high discharge capacity and good rate capability. We have synthesized layered- spinel composite cathode material 0.5Li2MnO3-0.25LiMn2O4 -0.25LiNi0.5Mn0.5O2 by sol-gel synthesis technique and surface characterized using XRD, Raman, SEM and EDX. Peaks corresponding to layered and spinel structures are identified by XRD and Raman studies. SEM images depict the nano-sized particles and EDX data confirms the presence of constituent transition metals and oxygen. Electrochemical studies were performed on coin cells, which were assembled in the Ar- filled glove box using Li as anode and spread material as cathode. LiPF6 with EC:DMC::1:2 ratio was used as the electrolyte. CV, EIS and charge discharge studies shows that the developed cathode material is a promising electrode for next generation Li ion batteries. Nasa Epscore Grant.

  7. 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. PMID:27437556

  8. Impact of active material surface area on thermal stability of LiCoO2 cathode

    NASA Astrophysics Data System (ADS)

    Geder, Jan; Hoster, Harry E.; Jossen, Andreas; Garche, Jürgen; Yu, Denis Y. W.

    2014-07-01

    Thermal stability of charged LiCoO2 cathodes with various surface areas of active material is investigated in order to quantify the effect of LiCoO2 surface area on thermal stability of cathode. Thermogravimetric analyses and calorimetry have been conducted on charged cathodes with different active material surface areas. Besides reduced thermal stability, high surface area also changes the active material decomposition reaction and induces side reactions with additives. Thermal analyses of LiCoO2 delithiated chemically without any additives or with a single additive have been conducted to elaborate the effect of particle size on side reactions. Stability of cathode-electrolyte system has been investigated by accelerating rate calorimetry (ARC). Arrhenius activation energy of cathode decomposition has been calculated as function of conversion at different surface area of active material.

  9. 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. PMID:27411083

  10. Structural predictions based on the compositions of cathodic materials by first-principles calculations

    NASA Astrophysics Data System (ADS)

    Li, Yang; Lian, Fang; Chen, Ning; Hao, Zhen-jia; Chou, Kuo-chih

    2015-05-01

    A first-principles method is applied to comparatively study the stability of lithium metal oxides with layered or spinel structures to predict the most energetically favorable structure for different compositions. The binding and reaction energies of the real or virtual layered LiMO2 and spinel LiM2O4 (M = Sc-Cu, Y-Ag, Mg-Sr, and Al-In) are calculated. The effect of element M on the structural stability, especially in the case of multiple-cation compounds, is discussed herein. The calculation results indicate that the phase stability depends on both the binding and reaction energies. The oxidation state of element M also plays a role in determining the dominant structure, i.e., layered or spinel phase. Moreover, calculation-based theoretical predictions of the phase stability of the doped materials agree with the previously reported experimental data.

  11. 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.

  12. Study Of Erosion Rates And Surface Effects of Different Hollow Cathode Materials During Vacuum Microarc Discharge

    SciTech Connect

    Atta Khedr, M.; Abdel Moneim, H.M.

    2005-03-17

    Studies of the properties of the emitted plasma from graphite, titanium, titanium Carbide, Stainless Steel, Cupper and Molybdenum Hollow Cathode materials during vacuum microarc were carried out. Using high voltage of 30 KV, short arc duration (0.5 - 4 {mu}s) and arc currents (100 - 450 A), each cathode material was subjected to 1000-3000 arc discharges under high vacuum (10-8 mbar) conditions. The angular distributions for the evaporants in each case were measured and show an exponential isotropic distribution in agreement with the theoretical predictions. The total erosion rates of evaporants and molten droplets were estimated and showed clearly their, dependence on the cathode material and on the hollow cathode geometry. The damages on the cathode surfaces and the inside of the hollow cathodes were investigated by the scanning electron microscope. Crater formation were formed spreading inside the hole of the hollow cathodes as well as on the rim surfaces and were found to differ according to both geometry and material of the hollow cathodes. The crater evacuation velocity and plasma pressure were determined. The damage on the anode tip showed erosion on the pen anode tip to the extent of drilling hole. The mechanism responsible for such phenomena is discussed.

  13. Nanoporous selenium as a cathode material for rechargeable lithium-selenium batteries.

    PubMed

    Liu, Lili; Hou, Yuyang; Wu, Xiongwei; Xiao, Shiying; Chang, Zheng; Yang, Yaqiong; Wu, Yuping

    2013-12-21

    Nanoporous selenium was prepared by a simple mechanical method adopting nano-CaCO3 as a template. When used as a cathode, it can exhibit relatively high capacity and good cycling behaviour. These results present great promise for this new cathode material for rechargeable lithium batteries of high energy density. PMID:24175320

  14. Particle size effect of Ni-rich cathode materials on lithium ion battery performance

    SciTech Connect

    Hwang, Ilkyu; Department of Chemical Engineering, Kyungppok National University, Daegu 702-701 ; Lee, Chul Wee; Kim, Jae Chang; Yoon, Songhun

    2012-01-15

    Graphical abstract: The preparation condition of Ni-rich cathode materials was investigated. When the retention time was short, a poor cathode performance was observed. For long retention time condition, cathode performance displayed a best result at pH 12. Highlights: Black-Right-Pointing-Pointer Ni-rich cathode materials (LiNi{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2}) were prepared by co-precipitation method using separate addition of Al salt. Black-Right-Pointing-Pointer Particle size of Ni-rich cathode materials became larger with increase of retention time and solution pH. Black-Right-Pointing-Pointer Cathode performance was poor for low retention time. Black-Right-Pointing-Pointer Optimal pH for co-precipitation was 12. -- Abstract: Herein, Ni-rich cathode materials (LiNi{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2}) in lithium ion batteries are prepared by a separate addition of Ni/Co salt and Al sol solution using a continuously stirred tank reactor. Retention time and solution pH were controlled in order to obtain high performance cathode material. Particle size increase was observed with a higher retention time of the reactants. Also, primary and secondary particles became smaller according to an increase of solution pH, which was probably due to a decrease of growth rate. From the cathode application, a high discharge capacity (175 mAh g{sup -1}), a high initial efficiency (90%) and a good cycleability were observed in the cathode material prepared under pH 12 condition, which was attributed to its well-developed layered property and the optimal particle size. However, rate capability was inversely proportional to the particle size, which was clarified by a decrease of charge-transfer resistance measured in the electrochemical impedance spectroscopy.

  15. 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

  16. 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

    2015-01-01

    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

  17. 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.

  18. 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.

  19. A review of blended cathode materials for use in Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Chikkannanavar, Satishkumar B.; Bernardi, Dawn M.; Liu, Lingyun

    2014-02-01

    Several commercial automotive battery suppliers have developed lithium ion cells which use cathodes that consist of a mixture of two different active materials. This approach is intended to take advantage of the unique properties of each material and optimize the performance of the battery with respect to the automotive operating requirements. Certain cathode materials have high coulombic capacity and good cycling characteristics, but are costly and exhibit poor thermal stability (e.g., LiNixCo1-x-yAlyO2). Alternately, other cathode materials exhibit good thermal stability, high voltage and high rate capability, but have low capacity (e.g., LiMn2O4). By blending two cathode materials the shortcomings of the parent materials could be minimized and the resultant blend can be tailored to have a higher energy or power density coupled with enhanced stability and lower cost. In this review, we survey the developing field of blended cathode materials from a new perspective. Targeting a range of cathode materials, we survey the advances in the field in the current review. Limitations, such as capacity decay due to metal dissolution are also discussed, as well as how the appropriate balance of characteristics of the blended materials can be optimized for hybrid- and electric-vehicle applications.

  20. 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. PMID:25394186

  1. Factors Affecting the Battery Performance of Anthraquinone-based Organic Cathode Materials

    SciTech Connect

    Xu, Wu; Read, Adam L.; Koech, Phillip K.; Hu, Dehong; Wang, Chong M.; Xiao, Jie; Padmaperuma, Asanga B.; Graff, Gordon L.; Liu, Jun; Zhang, Jiguang

    2012-02-01

    Two organic cathode materials based on poly(anthraquinonyl sulfide) structure with different substitution positions were synthesized and their electrochemical behavior and battery performances were investigated. The substitution positions on the anthraquinone structure, binders for electrode preparation and electrolyte formulations have been found to have significant effects on the battery performances of such organic cathode materials. The substitution position with less steric stress has higher capacity, longer cycle life and better high-rate capability. Polyvinylidene fluoride binder and ether-based electrolytes are favorable for the high capacity and long cycle life of the quinonyl organic cathodes.

  2. 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. PMID:27487940

  3. 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. PMID:26323202

  4. 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. PMID:24924807

  5. Selenium and selenium-sulfur cathode materials for high-energy rechargeable magnesium batteries

    NASA Astrophysics Data System (ADS)

    Zhao-Karger, Zhirong; Lin, Xiu-Mei; Bonatto Minella, Christian; Wang, Di; Diemant, Thomas; Behm, R. Jürgen; Fichtner, Maximilian

    2016-08-01

    Magnesium (Mg) is an attractive metallic anode material for next-generation batteries owing to its inherent dendrite-free electrodeposition, high capacity and low cost. Here we report a new class of Mg batteries based on both elemental selenium (Se) and selenium-sulfur solid solution (SeS2) cathode materials. Elemental Se confined into a mesoporous carbon was used as a cathode material. Coupling the Se cathode with a metallic Mg anode in a non-nucleophilic electrolyte, the Se cathode delivered a high initial volumetric discharge capacity of 1689 mA h cm-3 and a reversible capacity of 480 mA h cm-3 was retained after 50 cycles at a high current density of 2 C. The mechanistic insights into the electrochemical conversion in Mg-Se batteries were investigated by microscopic and spectroscopic methods. The structural transformation of cyclic Se8 into chainlike Sen upon battery cycling was revealed by ex-situ Raman spectroscopy. In addition, the promising battery performance with a SeS2 cathode envisages the perspective of a series of SeSn cathode materials combining the benefits of both selenium and sulfur for high energy Mg batteries.

  6. Spinel electrodes for rechargeable lithium batteries.

    SciTech Connect

    Thackeray, M. M.

    1999-11-10

    This paper gives a historical account of the development of spinel electrodes for rechargeable lithium batteries. Research in the late 1970's and early 1980's on high-temperature . Li/Fe{sub 3}O{sub 4} cells led to the evaluation of lithium spinels Li[B{sub 2}]X{sub 4} at room temperature (B = metal cation). This work highlighted the importance of the [B{sub 2}]X{sub 4}spinel framework as a host electrode structure and the ability to tailor the cell voltage by selection of different B cations. Examples of lithium-ion cells that operate with spinel anode/spinel cathode couples are provided. Particular attention is paid to spinels within the solid solution system Li{sub 1+x}Mn{sub 2-x}O{sub 4} (0 {le} x {le} 0.33).

  7. 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.

  8. Characterization of Cathode Materials for Rechargeable Lithium Batteries using Synchrotron Based In Situ X-ray Techniques

    SciTech Connect

    Yang, Xiao-Qing

    2007-05-23

    The emergence of portable telecommunication, computer equipment and ultimately hybrid electric vehicles has created a substantial interest in manufacturing rechargeable batteries that are less expensive, non-toxic, operate for longer time, small in size and weigh less. Li-ion batteries are taking an increasing share of the rechargeable battery market. The present commercial battery is based on a layered LiCoO{sub 2} cathode and a graphitized carbon anode. LiCoO{sub 2} is expensive but it has the advantage being easily manufactured in a reproducible manner. Other low cost layered compounds such as LiNiO{sub 2}, LiNi{sub 0.85}Co{sub 0.15}O{sub 2} or cubic spinels such as LiMn{sub 2}O{sub 4} have been considered. However, these suffer from cycle life and thermal stability problems. Recently, some battery companies have demonstrated a new concept of mixing two different types of insertion compounds to make a composite cathode, aimed at reducing cost and improving self-discharge. Reports clearly showed that this blending technique can prevent the decline in ·capacity caused by cycling or storage at elevated temperatures. However, not much work has been reported on the charge-discharge characteristics and phase transitions for these composite cathodes. Understanding the structure and structural changes of electrode materials during the electrochemical cycling is the key to develop better .lithium ion batteries. The successful commercialization of the· lithium-ion battery is mainly built on the advances in solid state chemistry of the intercalation compounds. Most of the progress in understanding the lithium ion battery materials has been obtained from x-ray diffraction studies. Up to now, most XRD studies on lithium-ion battery materials have been done ex situ. Although these ex situ XRD studies have provided important information· about the structures of battery materials, they do face three major problems. First of all, the pre-selected charge (discharge) states may

  9. Role of surface coating on cathode materials for lithium-ion batteries.

    SciTech Connect

    Chen, Z.; Qin, Y.; Amine, K.; Sun, Y.-K.

    2010-01-01

    Surface coating of cathode materials has been widely investigated to enhance the life and rate capability of lithium-ion batteries. The surface coating discussed here was divided into three different configurations which are rough coating, core shell structure coating and ultra thin film coating. The mechanism of surface coating in achieving improved cathode performance and strategies to carry out this surface modification is discussed. An outlook on atomic layer deposition for lithium ion battery is also presented.

  10. Final Report on Materials Characterization for the Wetted Cathodes for Low-Temperature Aluminum Smelting Program

    SciTech Connect

    Windisch, Charles F.

    2002-10-30

    This report is a summary of materials characterization results on twenty cathode samples that were used in a novel aluminum reduction cell at the Northwest Aluminum Technologies laboratory. Most of these cathodes were based on the TiB2 composition and showed very little corrosion as a result of testing. Most of the samples also showed good wetting by Al metal that formed during cell operation.

  11. Strain-induced tuning of surface energetics, electron conductivity and reduction drive in spinel LiMn2O4 cathodes

    NASA Astrophysics Data System (ADS)

    Scivetti, Ivan; Teobaldi, Gilberto

    LiMn2O4 (LMO) implementation in cathodes of rechargeable Li-ion batteries (LIBs) is hampered by the limited lifetime of the material and the stability of its interfaces, starting from the Solid Electrolyte Interphase. Recent experiments and Density Functional Theory (DFT) simulations indicate that the formation and effectiveness of the SEI on LMO are related to the surface orientation. In this context, we analyse the role of geometrical strain for the relative energy, magnetic ordering and the reduction drive of several LMO surfaces. DFT simulations reveal LMO surfaces to be markedly sensitive to geometrical strain. Strain lower than 10% can lead to insulator-metal and ferromagnetic-antiferromagnetic transitions, alter the relative energy of LMO surfaces, and induce changes as large as 1.0 eV in the surface chemical potential, thence the reduction drive. Prompted by advances in the synthesis of metal-oxide core-shell nanostructures, the use of strained LMO coating to enhance SEI-formation is put forward as a potential nano-engineered strategy for longer lived SEI on LMO substrates. Eu FP7 project SIRBATT (Ref. 608502, end date: August 2016).

  12. 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.

  13. Carbon incorporation effects and reaction mechanism of FeOCl cathode materials for chloride ion batteries

    NASA Astrophysics Data System (ADS)

    Zhao, Xiangyu; Li, Qiang; Yu, Tingting; Yang, Meng; Fink, Karin; Shen, Xiaodong

    2016-01-01

    Metal oxychlorides are proved to be new cathode materials for chloride ion batteries. However, this kind of cathode materials is still in a very early stage of research and development. The obtained reversible capacity is low and the electrochemical reaction mechanism concerning chloride ion transfer is not clear. Herein, we report FeOCl/carbon composites prepared by mechanical milling of the as-prepared FeOCl with carbon nanotube, carbon black or graphene nanoplatelets as cathode materials for chloride ion batteries. The electrochemical performance of the FeOCl electrode is evidently improved by the incorporation of graphene into the cathode. FeOCl/graphene cathode shows a high reversible capacity of 184 mAh g-1 based on the phase transformation between FeOCl and FeO. Two stages of this phase transformation are observed for the FeOCl cathode. New insight into the reaction mechanism of chloride ion dissociation of FeOCl is investigated by DFT + U + D2 calculations.

  14. Carbon incorporation effects and reaction mechanism of FeOCl cathode materials for chloride ion batteries

    PubMed Central

    Zhao, Xiangyu; Li, Qiang; Yu, Tingting; Yang, Meng; Fink, Karin; Shen, Xiaodong

    2016-01-01

    Metal oxychlorides are proved to be new cathode materials for chloride ion batteries. However, this kind of cathode materials is still in a very early stage of research and development. The obtained reversible capacity is low and the electrochemical reaction mechanism concerning chloride ion transfer is not clear. Herein, we report FeOCl/carbon composites prepared by mechanical milling of the as-prepared FeOCl with carbon nanotube, carbon black or graphene nanoplatelets as cathode materials for chloride ion batteries. The electrochemical performance of the FeOCl electrode is evidently improved by the incorporation of graphene into the cathode. FeOCl/graphene cathode shows a high reversible capacity of 184 mAh g−1 based on the phase transformation between FeOCl and FeO. Two stages of this phase transformation are observed for the FeOCl cathode. New insight into the reaction mechanism of chloride ion dissociation of FeOCl is investigated by DFT + U + D2 calculations. PMID:26777572

  15. 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.

  16. 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.

  17. 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. PMID:24776820

  18. One-Pot Hydrothermal Synthesis of LiMn2O4 Cathode Material with Excellent High-Rate and Cycling Properties

    NASA Astrophysics Data System (ADS)

    Jiang, Qianqian; Wang, Xingyao; Zhang, Han

    2016-08-01

    The spinel LiMn2O4 was prepared by a one-step hydrothermal method using acetone as the reductant under different hydrothermal temperatures. X-ray diffraction and scanning electron microscopy analysis indicated that optimal LiMn2O4 particles (LMO-120) were synthesized at the temperature of 120°C and the particles were well distributed and about 410 nm in size. Electrochemical performance showed that the as-prepared LiMn2O4 particles exhibited a higher initial discharge capacity than commercial LiMn2O4 (131.5 mAh g-1 versus 115.6 mAh g-1 at 0.2 C). An excellent discharge capacity retention rate of 94.07% was observed after 60 charge-discharge cycles. On the other hand, when cycled at the high rate of 1 C, the optimal LiMn2O4 in this work showed a high discharge capacity of 107.5 mAh g-1 in contrast to only 92.3 mAh g-1 of the commercial LiMn2O4. These results indicate that LMO-120 showed excellent electrochemical performance, especially the prolonged cycling life and high-rate performance, which suggested that this spinel LiMn2O4 has promise for practical application as a high-rate cathode material for lithium ion batteries.

  19. One-Pot Hydrothermal Synthesis of LiMn2O4 Cathode Material with Excellent High-Rate and Cycling Properties

    NASA Astrophysics Data System (ADS)

    Jiang, Qianqian; Wang, Xingyao; Zhang, Han

    2016-05-01

    The spinel LiMn2O4 was prepared by a one-step hydrothermal method using acetone as the reductant under different hydrothermal temperatures. X-ray diffraction and scanning electron microscopy analysis indicated that optimal LiMn2O4 particles (LMO-120) were synthesized at the temperature of 120°C and the particles were well distributed and about 410 nm in size. Electrochemical performance showed that the as-prepared LiMn2O4 particles exhibited a higher initial discharge capacity than commercial LiMn2O4 (131.5 mAh g-1 versus 115.6 mAh g-1 at 0.2 C). An excellent discharge capacity retention rate of 94.07% was observed after 60 charge-discharge cycles. On the other hand, when cycled at the high rate of 1 C, the optimal LiMn2O4 in this work showed a high discharge capacity of 107.5 mAh g-1 in contrast to only 92.3 mAh g-1 of the commercial LiMn2O4. These results indicate that LMO-120 showed excellent electrochemical performance, especially the prolonged cycling life and high-rate performance, which suggested that this spinel LiMn2O4 has promise for practical application as a high-rate cathode material for lithium ion batteries.

  20. 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.

  1. 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.

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

    NASA Astrophysics Data System (ADS)

    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 La1.50Sr0.50Ga3O7.25 has been extensively investigated by X-ray powder diffraction in a wide temperature range (up to 1573 K). Perovskite-type La0.8Sr0.2MnO3-d and La0.8Sr0.2Fe0.8Cu0.2O3-d and K2NiF4-type La2NiO4+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.

  3. 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.

  4. 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.

  5. Electrochemical behaviour of mono-chloronitrobenzene as cathode material for magnesium reserve batteries

    NASA Astrophysics Data System (ADS)

    Thirunakaran, R.; Vasudevan, S.; Sivashanmugam, A.; Gopukumar, S.

    Mono-chloronitrobenzene (MCNB) is investigated as a cathode material for magnesium reserve batteries that use a magnesium anode and a 2 M magnesium perchlorate aqueous electrolyte. The composition of the conducting material (acetylene black) in the cathode mix is optimized to obtain better electrochemical performance. The reduction mechanism of mono-chloronitrobenzene is examined by means of cyclic voltammetry using a glassy carbon electrode. Discharge studies at different current drains indicate that Mg-MCNB cells exhibit the highest Coulombic efficiency (86%) at a current drain of 100 mA. The reduction of MCNB to mono-chloroaniline is irreversible and diffusion-controlled.

  6. 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.

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

    PubMed

    Sun, Yang-Kook; Myung, Seung-Taek; Park, Byung-Chun; Prakash, Jai; Belharouak, Ilias; Amine, Khalil

    2009-04-01

    Layered lithium nickel-rich oxides, Li[Ni(1-x)M(x)]O(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(-1) and retained 96% of this capacity after 50 charge-discharge cycles under an aggressive test profile (55 degrees 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(0.8)Co(0.1)Mn(0.1)]O(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. PMID:19305398

  8. 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

  9. 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.

  10. Solution synthesis and characterization of lithium manganese oxide cathode materials

    SciTech Connect

    Voigt, J.A.; Boyle, T.J.; Doughty, D.H.

    1995-07-01

    A nonaqueous coprecipitation process has been developed to prepare controlled stoichiometry lithium manganese oxalate precipitates. The process involved mixing a methanolic Li-Mn nitrate solution with a methanolic solution containing tetramethylammonium oxalate as the precipitating agent. The resulting oxalates were readily converted to a variety of phase pure lithium manganese oxides at moderate temperatures ({le}600{degrees}C), where the phase formed was determined by the initial Li/Mn ratio in the starting solution. Metal cation dopants have been incorporated into the oxalate precipitate by dissolving the appropriate metal nitrate in the Li-Mn precursor solution The various starting solutions, oxalate precipitates, and calcined oxides have been extensively characterized using a variety of techniques, including {sup 7}Li NMR, TGA/DTA, SEM, and XRD. Results indicate that a strong interaction occurs between Li and Mn in the nitrate solution which carries over into the oxalate phase during precipitation. The morphology and the crystallite size of the oxide powders were shown to be controlled by the morphology of the oxalate precursor and the oxalate calcination temperature, respectively. The results of initial cathode performance tests with respect to dopant type (Al, Ni, Co) and concentration for LiMn{sub 2}O{sub 4} are also reported.

  11. 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.

  12. Endurance test on a single cell of a novel cathode material for MCFC

    NASA Astrophysics Data System (ADS)

    Soler, J.; González, T.; Escudero, M. J.; Rodrigo, T.; Daza, L.

    The molten carbonate fuel cell (MCFC) is expected to be an efficient device for the conversion of chemical energy in the near future. However, one of the major limits to the lifetime is the dissolution of the nickel oxide cathode in the electrolyte. This problem can be overcome by the addition of new compounds to the nickel oxide. In this way, the performance and the endurance of a new Ni-Ce cathode for MCFC has been tested and the results compared to a commercial nickel cathode. The polarisation curves were measured in order to check the degradation of the cell performance with time. The results showed a better performance with the novel cathode material (136 mW/cm 2 at 200 mA/cm 2 during 2100 h) than the commercial one (the voltage decreased from 120 to 108 mW/cm 2 at 150 mA/cm 2 in 1000 h). The better performance of Ni-Ce cathode with respect to the Ni one can be attributed to the good effect of cerium in the cathode. The change in the nickel crystalline structure reduces the dissolution of nickel in the electrolyte and implies a greater endurance of the cell. The current-voltage curves were measured and showed the same trend for both cells. Postmortem analyses were done in order to characterise the cells. As a conclusion, the addition of cerium can be beneficial to overcome the dissolution of the nickel cathode in the electrolyte, which is considered one of the major limits to the lifetime of a MCFC.

  13. Catalyzed electrochemical gasification of carbonaceous materials at anode and electrowinning of metals at cathode

    SciTech Connect

    Vaughan, R.J.

    1983-09-20

    The electrochemical gasification reaction of carbonaceous materials by anodic oxidation in an aqueous acidic electrolyte to produce oxides of carbon at the anode and metallic elements at the cathode of an electrolysis cell is catalyzed by the use of an iron catalyst.

  14. 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.

  15. Different materials as a cathode modification layer on the impact of organic solar cells

    NASA Astrophysics Data System (ADS)

    Zhong, Jian; Huang, Qiuyan; Yu, Junsheng; Jiang, Yadong

    2010-10-01

    Organic thin film solar cells based on conjugated polymer or small molecules have showed an interesting approach to energy conversion since Tang reported a single donor-accepter hetero-junction solar cell. The power conversion efficiency of organic solar cells has increased steadily over last decade. Small-molecular weight organic double heterojunction donor-acceptor layer organic solar cells (OSC) with a structure of indium-tin-oxide (ITO)/CuPc(200Å)/C60(400Å)/x/Ag(1000Å), using CuPc(copper Phthalocyanine)as donor layer, and Alq3(8-Hydroxyquinoline aluminum salt), BCP(Bromocresol purple sodium salt) and Bphen(4'7-diphyenyl-1,10-phenanthroline) as cathode modification layer, respectively were fabricated. The performance of OSC was studied as a function of the different materials as an cathode modification layer to optimize the structure. The current-voltage characteristic of the solar cell under AM1.5 solar illumination at an intensity of 100 mw/cm2 showed that the power conversion efficiency (PCE) was dependent of the different materials of the cathode modification layer. the efficiency along with the different materials as an cathode modification layer will diminish under that standard solar illumination(AM1.5)was obtained. Using a double heterostructure of ITO/CuPc(200Å)/C60(400Å)/Alq3(60Å)/Ag(1000Å) with high-vacuum evaporation technology, the efficiency was 0.587%.the efficiency was 0.967% when the material of the cathode modification layer was BCP, with the structure of ITO/CuPc(200Å)/C60(400Å)/BCP(35Å)/Ag(1000Å), and the efficiency was 0.742% when the material of the cathode modification layer was Bphen, with the structure of ITO/CuPc(200Å)/C60(400Å)/ Bphen(50Å)/Ag(1000Å).Using different materials as a cathode modification layer, it can be seen that the material which matches the energy level could even eventually be able to improve the energy conversion efficiency more.

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

    DOE PAGESBeta

    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 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

  17. Mobility of cations in magnesium aluminate spinel

    NASA Astrophysics Data System (ADS)

    Martinelli, J. R.; Sonder, E.; Weeks, R. A.; Zuhr, R. A.

    1986-04-01

    Transport of cations in magnesium aluminate spinel due to an applied electric field at approximately 1000 °C has been measured by observing changes in elemental concentrations near the cathode and anode surfaces using ion backscattering techniques. The results indicate that magnesium ions are the mobile species at 1000 °C and that these ions combine with ambient oxygen at the cathode surface to form a MgO layer. Quantitative interpretation of the data leads to the conclusion that the ionic transference number of spinel becomes approximately 0.5 after treatment in an electric field.

  18. Influence of cathode material on generation of energetic hydrogen atoms in a glow discharge

    SciTech Connect

    Cvetanovic, N.; Obradovic, B. M.; Kuraica, M. M.

    2011-01-01

    In this paper influence of cathode material on formation of fast hydrogen atoms in an abnormal glow discharge is investigated using Balmer alpha emission spectroscopy. Energetic H atoms are generated in charge exchange reactions of hydrogen ions that are accelerated in the electric field, and also formed in the backscattering process at the cathode surface. Copper and graphite cathodes were used. Investigation was performed in two orthogonal directions of observation in pure hydrogen and argon-hydrogen mixture. The shapes of the profiles are examined together with the space intensity distribution of Balmer alpha line. Reduced atom reflection from graphite was manifested in the spectroscopic result, in accordance to the field acceleration model. The effect was evident only at high ion energies. This is explained by energy dependence of reflection coefficient for H atoms.

  19. 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.

  20. 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. PMID:26755764

  1. 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.

  2. Progress in High-Capacity Core-Shell Cathode Materials for Rechargeable Lithium Batteries.

    PubMed

    Myung, Seung-Taek; Noh, Hyung-Joo; Yoon, Sung-June; Lee, Eung-Ju; Sun, Yang-Kook

    2014-02-20

    High-energy-density rechargeable batteries are needed to fulfill various demands such as self-monitoring analysis and reporting technology (SMART) devices, energy storage systems, and (hybrid) electric vehicles. As a result, high-energy electrode materials enabling a long cycle life and reliable safety need to be developed. To ensure these requirements, new material chemistries can be derived from combinations of at least two compounds in a secondary particle with varying chemical composition and primary particle morphologies having a core-shell structure and spherical cathode-active materials, specifically a nanoparticle core and shell, nanoparticle core and nanorod shell, and nanorod core and shell. To this end, several layer core-shell cathode materials were developed to ensure high capacity, reliability, and safety. PMID:26270835

  3. Correlation of cathode parameters of high power grid tubes with material characteristics of cathode-grid units

    NASA Astrophysics Data System (ADS)

    Melnikova, Irina P.; Polyakov, Igor V.; Usanov, Dmitry A.

    2005-09-01

    One way to increase the longevity of dispenser cathodes is based on reducing the Barium evaporation. This can be achieved by the decrease of the reaction "activity" of the emitter impregnant with the porous tungsten (W) body, which supplies free Barium from the interior of the porous cathode to its surface.

  4. 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.

  5. Exploiting chemically and electrochemically reactive phosphite derivatives for high-voltage spinel LiNi0.5Mn1.5O4 cathodes

    NASA Astrophysics Data System (ADS)

    Song, Young-Min; Kim, Choon-Ki; Kim, Ko-Eun; Hong, Sung You; Choi, Nam-Soon

    2016-01-01

    A family of organophosphorus compounds including triphenyl phosphite (TPP), trimethyl phosphite (TMP), tris(2,2,2-trifluoroethyl) phosphite (TFEP), and tris(trimethylsilyl) phosphite (TMSP) is investigated as additives for the stabilization of high-voltage LiNi0.5Mn1.5O4 (LNMO) cathode-electrolyte interface. Our investigation reveals that the cycling performance of Li/LNMO half cells with the TMP, TFEP or TMSP additive is drastically improved at 60 °C compared to the baseline electrolyte. Among the various phosphite-based additives tested, TMSP additive enables facile Li ion transport at high C rates and significantly enhances the storage performance of the Li/LNMO cells at 60 °C. To understand the effects of the phosphite-based additives on electrolyte oxidative decomposition at high voltages, the surface chemistry of the cathode after precycling is investigated via ex-situ X-ray photoelectron spectroscopy (XPS). Additionally, the roles of phosphite-based additives to suppress LiPF6 hydrolysis and to remove HF are examined via 19F and 31P NMR spectroscopies.

  6. Composite cathode materials development for intermediate temperature solid oxide fuel cell systems

    NASA Astrophysics Data System (ADS)

    Qin, Ya

    Solid oxide fuel cell (SOFC) systems are of particular interest as electrochemical power systems that can operate on various hydrocarbon fuels with high fuel-to-electrical energy conversion efficiency. Within the SOFC stack, La0.8Sr 0.2Ga0.8Mg0.115Co0.085O3-delta (LSGMC) has been reported as an optimized composition of lanthanum gallate based electrolytes to achieve higher oxygen ionic conductivity at intermediate temperatures, i.e., 500-700°C. The electrocatalytic properties of interfaces between LSGMC electrolytes and various candidate intermediate-temperature SOFC cathodes have been investigated. Sm0.5Sr0.5CoO 3-delta (SSC), and La0.6Sr0.4Co0.2Fe 0.8O3-delta (LSCF), in both pure and composite forms with LSGMC, were investigated with regards to both oxygen reduction and evolution, A range of composite cathode compositions, having ratios of SSC (in wt.%) with LSGMC (wt.%) spanning the compositions 9:1, 8:2, 7:3, 6:4 and 5:5, were investigated to determine the optimal cathode-electrolyte interface performance at intermediate temperatures. All LSGMC electrolyte and cathode powders were synthesized using the glycine-nitrate process (GNP). Symmetrical electrochemical cells were investigated with three-electrode linear dc polarization and ac impedance spectroscopy to characterize the kinetics of the interfacial reactions in detail. Composite cathodes were found to perform better than the single phase cathodes due to significantly reduced polarization resistances. Among those composite SSC-LSGMC cathodes, the 7:3 composition has demonstrated the highest current density at the equivalent overpotential values, indicating that 7:3 is an optimal mixing ratio of the composite cathode materials to achieve the best performance. For the composite SC-LSGMC cathode/LSGMC interface, the cathodic overpotential under 1 A/cm2 current density was as low as 0.085 V at 700°C, 0.062V at 750°C and 0.051V at 800°C in air. Composite LSCF-LSGMC cathode/LSGMC interfaces were found to have

  7. Local structure modification in lithium rich layered Li-Mn-O cathode material

    NASA Astrophysics Data System (ADS)

    Giorgetti, Marco; Wang, Diandian; Aquilanti, Giuliana; Buchholz, Daniel; Passerini, Stefano

    2016-05-01

    X-ray absorption spectroscopy (XAS) is applied to study the local geometry of Co, Ni, and Mn sites in a new high voltage cathode for lithium batteries. The material is a solid solution between Li2MnO3 and Li(x)Mn0.4Ni0.4Co0.2O2. The XAS technique has permitted to check the local atomic structure and charge associated with the metals in a series of electrodes with different lithium concentration x, obtained during the first charge operation, and compared to the first discharge and a successive charge. The ex-situ XAS investigation on the initial activation of the cathode material (first charge) can be described by two separated reaction of LiMO2 (M = Ni and Co) and Li2MnO3. The strength and limitations of the ExAFS approach in these materials is underlined.

  8. Spinel: where did it go?

    NASA Astrophysics Data System (ADS)

    Roy, Donald W.

    1997-11-01

    Polycrystalline magnesium aluminum oxide, transparent from 200 nanometers to 6 microns, offers a unique combination of optical and physical properties. A superior dome and window material in respect to rain and particle erosion, solar radiation, high temperatures and humidity; it is resistant to attack by strong acids, sea water, and jet fuels. Although it had been qualified for, and designed into several advanced UV/visible/IR optical systems, production of hot-pressed Spinel was stopped at Alpha Optical Systems in 1993 by the parent company Coors Ceramics. Development efforts on cold-pressed/sinter/HIP Spinel at RCS Technologies are reportedly stalemated at the present time. Therefore, there is no known significant effort directed toward the development of polycrystalline Spinel. however, the author is in contact with both domestic and foreign laboratories which have expressed a desire to develop the technology for transparent Spinel. Renewed development may begin during calendar year 1997. Because of the apparent continuing significant interest in Spinel this paper will review the properties of Spinel and will compare the most significant properties of Spinel with sapphire and aluminum oxynitride. The limitations of competing manufacturing processes, will be mentioned. Grinding and polishing considerations will be reviewed in respect to maximizing optical and structural properties.

  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. 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. PMID:24607415

  11. 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

  12. Glass-containing composite cathode contact materials for solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Tucker, Michael C.; Cheng, Lei; DeJonghe, Lutgard C.

    2011-10-01

    The feasibility of adding glass to conventional SOFC cathode contact materials in order to improve bonding to adjacent materials in the cell stack is assessed. A variety of candidate glass compositions are added to LSM and SSC. The important properties of the resulting composites, including conductivity, sintering behavior, coefficient of thermal expansion, and adhesion to LSCF and Mn1.5Co1.5O4-coated 441 stainless steel are used as screening parameters. Adhesion of LSM to LSCF improved from 3.9 to 5.3 MPa upon addition of SCZ-8 glass. Adhesion of LSM to coated stainless steel improved from 1.8 to 3.9 MPa upon addition of Schott GM31107 glass. The most promising cathode contact material/glass composites are coated onto Mn1.5Co1.5O4-coated 441 stainless steel substrates and subjected to area-specific resistance testing at 800 °C. In all cases, area-specific resistance is found to be in the range 2.5-7.5 mOhm cm2 and therefore acceptable. Indeed, addition of glass is found to improve bonding of the cathode contact material layer without sacrificing acceptable conductivity.

  13. 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.

  14. 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.

  15. Theoretical investigation of Chevrel phase materials for cathodes accommodating Ca2+ ions

    NASA Astrophysics Data System (ADS)

    Smeu, Manuel; Hossain, Md Sazzad; Wang, Zi; Timoshevskii, Vladimir; Bevan, Kirk H.; Zaghib, Karim

    2016-02-01

    The Chevrel phase compounds Mo6X8 (X = S, Se, Te) are theoretically studied by ab initio methods as potential candidates for battery cathode materials. The voltage profiles are calculated for the cases of various alkaline earth metals (Mg, Ca, Sr, Ba) serving as guest intercalation ions. The Ca ions are shown to offer the practically significant voltage of ∼1.0-1.25 V, with S substitution giving the highest voltage over Se and Te. We further demonstrate that doubling the capacity of such a battery would also be possible by incorporating a second Ca ion near the Mo6X8 cluster. The electronic properties of this material are investigated, revealing that the entire Mo6 cluster behaves as a redox center. Finally, the ion diffusion barriers are calculated, showing comparable values to existing battery materials. This work demonstrates that the Chevrel phase may be useful as a cathode material for intercalating divalent ions, and also offers insights into possible tuning of cathode properties by judicious selection of the constituents.

  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. 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.

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

    NASA Astrophysics Data System (ADS)

    Chen, Xin; Sanmartín, J. R.

    2012-07-01

    A new material, C12A7:e- 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.

  19. Magnetostructural coupling in spinel oxides

    NASA Astrophysics Data System (ADS)

    Kemei, Moureen

    2015-03-01

    Spinels oxides are of great interest functionally as multiferroic, battery, and magnetic materials as well as fundamentally because they exhibit novel spin, structural, and orbital ground states. Competing interactions are at the heart of novel functional behavior in spinels. Here, we explore the intricate landscape of spin, lattice, and orbital interactions in magnetic spinels by employing variable-temperature high-resolution synchrotron x-ray powder diffraction, total neutron scattering, magnetic susceptibility, dielectric, and heat capacity measurements. We show that the onset of long-range magnetic interactions often gives rise to lattice distortions. Our work illustrates that the spinels NiCr2O4, CuCr2O4,andMn3O4, which are tetragonal at room temperature due to Jahn-Teller ordering, undergo further spin-driven structural distortions at the onset of long-range ferrimagnetic order. We have also studied the complete structural description of the ground states of several spinels including the geometrically frustrated spinels ZnCr2O4andMgCr2O4. The detailed spin-lattice studies of spinel oxides presented here illustrate the prevalence of structural phase coexistence when magnetostructural changes occur below 50 K. The new understanding of structural ground states in spinel oxides will guide the design of structure-property relationships in these materials. Broadly, this work highlights the importance of variable-temperature high-resolution synchrotron x-ray diffraction in understanding phase transitions in functional materials. Schlumberger Foundation Faculty for the Future fellowship, MRL Facilities funded by the NSF under Award No. DMR 1121053, and the Advanced Photon Source supported by the DOE, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

  20. Introduction of two lithiooxycarbonyl groups enhances cyclability of lithium batteries with organic cathode materials

    NASA Astrophysics Data System (ADS)

    Shimizu, Akihiro; Kuramoto, Hiroki; Tsujii, Yutaka; Nokami, Toshiki; Inatomi, Yuu; Hojo, Nobuhiko; Suzuki, Hirotetsu; Yoshida, Jun-ichi

    2014-08-01

    To increase the cyclability of lithium batteries using organic cathode materials of low molecular weights, two lithiooxycarbonyl (-CO2Li) groups was introduced to p- and o-quinones. The introduction of two -CO2Li groups does not strongly affect the redox potentials of quinones. Lithium batteries using p- and o-quinones with two -CO2Li groups as cathode materials exhibit excellent cyclability compared to their parent quinones. In particular, pyrene-4,5,9,10-tetraone having two lithiooxycarbonyl groups (LCPYT) exhibited high energy density, high cyclability, and fast charge ability. These results indicate that introduction of two lithiooxycarbonyl groups to quinones serves as a simple and effective way to decrease the solubility of various quinones in electrolyte solutions without significant decrease in the voltage.

  1. 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.

  2. 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.

  3. Sulfur-based composite cathode materials for high-energy rechargeable lithium batteries.

    PubMed

    Wang, Jiulin; He, Yu-Shi; Yang, Jun

    2015-01-21

    There is currently an urgent demand for highly efficient energy storage and conversion systems. Due to its high theoretical energy density, low cost, and environmental compatibility, the lithium sulfur (Li-S) battery has become a typical representative of the next generation of electrochemical power sources. Various approaches have been explored to design and prepare sulfur cathode materials to enhance their electrochemical performance. This Research News article summarizes and compares different sulfur materials for Li-S batteries and particularly focuses on the fine structures, electrochemical performance, and electrode reaction mechanisms of pyrolyzed polyacrylo-nitrile sulfur (pPAN@S) and microporous-carbon/small-sulfur composite materials. PMID:25256595

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

    SciTech Connect

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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.

  6. 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

    2016-07-01

    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.

  7. 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

  8. New high capacity cathode materials for rechargeable Li-ion batteries: vanadate-borate glasses.

    PubMed

    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 - LiBO(2) 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 - LiBO(2) glasses are considered as promising cathode materials for rechargeable Li-ion batteries fabricated through rather simple and cost-efficient methods. PMID:25408200

  9. 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.

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

    PubMed

    Siegert, Michael; Yates, Matthew D; Call, Douglas F; Zhu, Xiuping; Spormann, Alfred; Logan, Bruce E

    2014-04-01

    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. 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. PMID:26634725

  12. Zero-Strain Na2FeSiO4 as Novel Cathode Material for Sodium-Ion Batteries.

    PubMed

    Li, Shouding; Guo, Jianghuai; Ye, Zhuo; Zhao, Xin; Wu, Shunqing; Mi, Jin-Xiao; Wang, Cai-Zhuang; Gong, Zhengliang; McDonald, Matthew J; Zhu, Zizhong; Ho, Kai-Ming; Yang, Yong

    2016-07-13

    A new cubic polymorph of sodium iron silicate, Na2FeSiO4, is reported for the first time as a cathode material for Na-ion batteries. It adopts an unprecedented cubic rigid tetrahedral open framework structure, i.e., F4̅3m, leading to a polyanion cathode material without apparent cell volume change during the charge/discharge processes. This cathode shows a reversible capacity of 106 mAh g(-1) and a capacity retention of 96% at 5 mA g(-1) after 20 cycles. PMID:27305627

  13. XAFS Study on Deterioration of Cathode Materials for Lithium-Ion Batteries

    SciTech Connect

    Nonaka, Takamasa; Okuda, Chikaaki; Kondo, Yasuhito; Seno, Yoshiki; Ukyo, Yoshio

    2007-02-02

    LiNi0.8CO0.15Al0.05O2, being one of the promising cathode materials for lithium-ion batteries, shows a distinct capacity fading after charge/discharge cycling and/or storage at high temperatures. The origin of these deteriorations has been explored by investigating the electronic and structural changes of the cathode material using X-ray absorption spectroscopy. Ni K-edge XAFS measurements were performed in two different modes: surface-sensitive conversion electron yield (CEY) mode and bulk-sensitive transmission mode. The Ni K-edge XANES showed that, after the cycle and aging tests, the Ni valences at the near-surface of the cathode particles became much lower than those in bulk. Whereas, the EXAFS showed that the bulk and surface-averaged Ni-O bond distances remained unchanged after the tests. These electronic and structural changes which occur prominently at near-surface are probably the main cause of the battery deterioration phenomenon.

  14. 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.

  15. Is alpha-V2O5 a cathode material for Mg insertion batteries?

    NASA Astrophysics Data System (ADS)

    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 α-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 α-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 α-V2O5.

  16. 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

  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

    DOE PAGESBeta

    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 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

  19. 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.

  20. Effect of the cathode material on the removal of nitrates by electrolysis in non-chloride media.

    PubMed

    Lacasa, Engracia; Cañizares, Pablo; Llanos, Javier; Rodrigo, Manuel A

    2012-04-30

    In this work, the effect of the cathode material (conductive diamond, stainless steel, silicon carbide, graphite or lead) and the current density (150-1400 A m(-2)) on the removal of nitrates from aqueous solutions is studied by electrolysis in non-divided electrochemical cells equipped with conductive diamond anodes, using sodium sulphate as the electrolyte. The results show that the cathode material very strongly influences both the process performance and the product distribution. The main products obtained are gaseous nitrogen (NO, N(2)O and NO(2)) and ammonium ions. Nitrate removal follows first order kinetics, which indicates that the electrolysis process is controlled by mass transfer. Furthermore, the stainless steel and graphite cathodes show a great selectivity towards the production of ammonium ions, whereas the silicon carbide cathode leads to the highest formation of gaseous nitrogen, which production is promoted at low current densities. PMID:22387000

  1. 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]. PMID:27331088

  2. Surface structure evolution of cathode materials for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Yingchun, Lyu; Yali, Liu; Lin, Gu

    2016-01-01

    Lithium ion batteries are important electrochemical energy storage devices for consumer electronics and the most promising candidates for electrical/hybrid vehicles. The surface chemistry influences the performance of the batteries significantly. In this short review, the evolution of the surface structure of the cathode materials at different states of the pristine, storage and electrochemical reactions are summarized. The main methods for the surface modification are also introduced. Project supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB07030200) and the National Basic Research Program of China (Grant Nos. 2014CB921002 and 2012CB921702).

  3. Covalently Functionalized Graphene by Radical Polymers for Graphene-Based High-Performance Cathode Materials.

    PubMed

    Li, Yongjun; Jian, Zukai; Lang, Meidong; Zhang, Chunming; Huang, Xiaoyu

    2016-07-13

    Polymer-functionalized graphene sheets play an important role in graphene-containing composite materials. Herein, functionalized graphene sheets covalently linked with radical polymer, graphene-graft-poly(2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl methacrylate) (G-g-PTMA), were prepared via surface-initiated atom transfer radical polymerization (SI-ATRP). A composite cathode with G-g-PTMA as major active material and reduced graphene oxide (RGO) as conductive additive was fabricated via a simple dispersing-depositing process, and this composite cathode exhibited a relatively high specific capacity up to 466 mAh g(-1) based on the mass of PTMA, which is much higher than the theoretical capacity of PTMA. This extraordinary electrochemical performance is attributed to the fast one-electron redox reaction of G-g-PTMA and surface Faradaic reaction of RGO boosted by G-g-PTMA, which suggested that G-g-PTMA sheets play a dual role in the composite materials, that is, on the one hand provided the fast one-electron redox reaction of PTMA and on the other hand worked as nanofiller for facilitating the surface Faradaic reaction-based lithium storage of RGO. PMID:27328986

  4. 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. PMID:26609636

  5. Investigation of the removing process of cathode material in micro-EDM using an atomistic-continuum model

    NASA Astrophysics Data System (ADS)

    Guo, Jianwen; Zhang, Guojun; Huang, Yu; Ming, Wuyi; Liu, Min; Huang, Hao

    2014-10-01

    In micro-electrical discharge machining (micro-EDM), the discharge duration is ultra-short, and both the electric action and the thermal action by the discharge channel play important roles in the removing process of cathode material. However, in most researches on the machining mechanism of micro-EDM, only the thermal action is concerned. In this article, a combined atomistic-continuum modeling method in which the two-temperature model and the molecular dynamics simulation model are integrated is used to construct the simulation model for cathode in single-discharge micro-EDM process. With this simulation model, removing processes of Cu cathode material in micro-EDM under pure thermal action, pure electric action and the combination of them are investigated in a simulative way. By analyzing evolutions of temperature, stress and micro-structure of material as well as the dynamical behaviors of material in the removing process, mechanisms of the cathode material removal and crater formation are revealed. In addition, the removing process of cathode material under the combination of pure thermal action and pure electric action is compared with those under the two pure actions respectively to analyze the interactive effect between the thermal action and the electric action.

  6. 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

  7. 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

  8. Strain-induced tuning of surface energy, electron conductivity, and reduction drive in spinel LiMn2O4 cathodes

    NASA Astrophysics Data System (ADS)

    Scivett, Ivan; Teobaldi, Gilberto

    LiMn2O4 (LMO) implementation in rechargeable Li-ion batteries (LIBs) for stationary storage is hampered by the limited lifetime of the material and its interfaces, starting from the Solid Electrolyte Interphase. Recent experiments and Density Functional Theory (DFT) simulations indicate that the formation and effectiveness of the SEI on LMO are related to the surface orientation and reduction drive. In this context, we analyse the role of geometrical strain for the relative energy, magnetic ordering and the reduction drive of several LMO surfaces. DFT simulations reveal LMO surfaces to be markedly sensitive to geometrical strain. Strain lower than 10% can induce insulator-metal and ferromagnetic-antiferromagnetic transitions, alter the relative energy of LMO surfaces, and induce changes as large as 1.0 eV in the surface chemical potential, thence reduction drive. Prompted by advances in the synthesis of metal-oxide core-shell nanostructures, use of strained LMO coating as SEI-formation agent is put forward towards engineering of longer lived SEI on LMO substrates. EU FP7 project SIRBATT (Ref. 608502, end date: August 2016)

  9. 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.

  10. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    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.

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

    PubMed

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

    2014-01-01

    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. PMID:25080933

  13. 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

  14. 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

    2016-08-01

    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. PMID:27060219

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

    PubMed

    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

  16. 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.

  17. Surface natures of conductive carbon materials and their contributions to charge/discharge performance of cathodes for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Lin, H. B.; Huang, W. Z.; Rong, H. B.; Hu, J. N.; Mai, S. W.; Xing, L. D.; Xu, M. Q.; Li, X. P.; Li, W. S.

    2015-08-01

    The surface natures of five carbon materials, acetylene black, Super P, ECP600JD, KS-6 and CNTs, are compared in terms of morphology, specific surface area and activity towards electrolyte decomposition and anion insertion, and their contributions as conductive additives to cathode performance of lithium ion batteries are understood. With the characterizations from scanning electron microscopy, Brunauer-Emmett-Teller analysis and cyclic voltammetry, it's demonstrated that: (1) the morphology is granular for acetylene black, Super P and ECP600JD, flake-like for KS-6 and wire-like for CNTs; (2) ECP600JD exhibits the largest specific surface area but KS-6 has the smallest one; (3) the activity is the same for all the samples towards the electrolyte decomposition but different from each other towards anion insertion. Charge/discharge tests of LiMn2O4 and LiNi0.5Mn1.5O4 cathodes indicate that the surface natures of carbon materials play an important role in charge/discharge performance of cathodes for lithium ion batteries. ECP600JD with smallest particle size provides the largest site for electrolyte decomposition leading to the lowest coulombic efficiency, while KS-6 with a layered structure exhibits the highest activity towards anion insertion leading to the lowest charge and discharge capacity of cathode materials. These negative effects become more significant when high voltage cathode materials are used.

  18. 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.

  19. 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.

  20. Strategies to curb structural changes of lithium/transition metal oxide cathode materials & the changes' effects on thermal & cycling stability

    DOE PAGESBeta

    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 themore » cathodes is one of the most critical factors in thermal runaway and related safety problems.« less

  1. 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).

  2. 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.

  3. Excellent cycling stability and superior rate capability of a graphene-amorphous FePO4 porous nanowire hybrid as a cathode material for sodium ion batteries.

    PubMed

    Yang, Gaoliang; Ding, Bing; Wang, Jie; Nie, Ping; Dou, Hui; Zhang, Xiaogang

    2016-04-28

    A porous nanowire material consisting of graphene-amorphous FePO4 was investigated as an advanced cathode material for sodium ion batteries for large-scale applications. This hybrid cathode material showed excellent cycling performance and superior rate capability, which were attributed to the porous nanowire structure and the existence of graphene. PMID:27064740

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

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

    In technologically important LiNi1-x-yMnxCoyO2 cathode materials, surface reconstruction from a layered to a rock-salt structure is commonly observed under a variety of operating conditions, particularly in Ni-rich compositions. This phenomenon contributes to poor high-voltage cycling performance, impeding attempts to improve the energy density by widening the potential window at which these electrodes operate. Here, using advanced nano-tomography and transmission electron microscopy techniques, we show that hierarchically structured LiNi0.4Mn0.4Co0.2O2 spherical particles, made by a simple spray pyrolysis method, exhibit local elemental segregation such that surfaces are Ni-poor and Mn-rich. The tailored surfaces result in superior resistance to surface reconstruction compared with those of conventional LiNi0.4Mn0.4Co0.2O2, as shown by soft X-ray absorption spectroscopy experiments. The improved high-voltage cycling behaviour exhibited by cells containing these cathodes demonstrates the importance of controlling LiNi1-x-yMnxCoyO2 surface chemistry for successful development of high-energy lithium ion batteries.

  5. Effect of carbon black materials on the electrochemical properties of sulfur-based composite cathode for lithium-sulfur cells.

    PubMed

    Jeong, Bo Ock; Kwon, Sang Woon; Kim, Tae Jeong; Lee, Eun Hee; Jeong, Seong Hun; Jung, Yongju

    2013-12-01

    To investigate the effect of the electrode materials on the electrochemical performance of Li-S cells, sulfur cathodes were constructed using four types of carbon blacks: Ketjenblack EC-600JD (KB-600), Printex XE-2, Cabot BP-2000, and Super-P. It was found that the electrochemical performance of sulfur cathode was strongly dependent on the type of carbon black used. In the first discharge, the sulfur cathodes containing carbon blacks with a high surface area, KB-600 (SBET = 1270 m2/g), Printex XE-2 (SBET = 950 m2/g), or Cabot BP-2000 (SBET = 1487 m2/g), showed much higher discharge capacities (>1200 mA h/g) than the sulfur cathode (710 mA h/g) with Super-P (SBET = 62 m2/g). It was observed that the sulfur cathodes with KB-600, Printex XE-2, or Cabot BP-2000, which showed very similar discharge capacities one another at a low rate of 0.2 C, exhibited significantly different electrochemical behavior (the discharge capacity and midvoltage) at a high rate of 1.0 C. In particular, the sulfur cathode with KB-600 showed an extremely high capacity (831 mA h/g) with a midvoltage of 2.07 V at a 1.0 C rate, and excellent capacity retention (79%) after 50 cycles. PMID:24266155

  6. 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

  7. Lithium iron phosphate spheres as cathode materials for high power lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Vu, Anh; Stein, Andreas

    2014-01-01

    Electrode materials composed of micrometer- and sub-micrometer-sized spherical particles are of interest for lithium ion batteries (LIBs) because spheres can be packed with higher efficiency than randomly shaped particles and achieve higher volumetric energy densities. Here we describe the synthesis of lithium iron phosphate (LFP) phases as cathode materials with spherical morphologies. Spherical Li3Fe2(PO4)3 particles and LiFePO4 spheres embedded in a carbon matrix are prepared through phase separation of precursor components in confinement. Precursors containing Li, Fe, and P sources, pre-polymerized phenol-formaldehyde (carbon source), and amphiphilic surfactant (F127) are confined in 3-dimensional (colloidal crystal template) or 2-dimensional (thin film) spaces, and form spherical LFP particles upon heat treatment. Spherical Li3Fe2(PO4)3 particles are fabricated by calcining LiFePO4/C composites in air at different temperatures. LiFePO4 spheres embedded in a carbon matrix are prepared by spin-coating the LFP/carbon precursor onto quartz substrates and then applying a series of heat treatments. The spherical Li3Fe2(PO4)3 cathode materials exhibit a capacity of 100 mA h g-1 (83% of theoretical) at 2.5 C rate. LiFePO4 spheres embedded in a carbon matrix have specific capacities of 130, 100, 83, and 50 mA h g-1 at C/2, 2 C, 4 C, and 16 C rates, respectively (PF_600_2), revealing excellent high-rate performance.

  8. 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). PMID:25322171

  9. 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%.

  10. Effect of Defects on Decay of Voltage and Capacity for Li[Li0.15Ni0.2Mn0.6]O2 Cathode Material.

    PubMed

    Yan, Wuwei; Liu, Yongning; Guo, Shengwu; Jiang, Tao

    2016-05-18

    Lithium-rich manganese metal layered oxides are very promising cathode materials for high-energy-density lithium-ion batteries, but improvement in voltage decay and capacity fade is a great challenge, which is mainly related to the structural instability or reconstruction of material's surface. Defects, such as part lattice distortions, local cation disordering and atomic ununiformity, often aggravate the further structural changes upon cycling. In this paper, we found that PEG contributed to form better layered structure, well crystallinity, uniform composition and polyhedral nanoparticles for Li[Li0.15Ni0.2Mn0.6]O2 (LNMO). On the basis of the comparative trial, a mechanism of electronegativity difference is proposed to elucidate cation nonuniform distribution. Higher electronegativity of Ni (1.91) than Mn (1.55) show a stronger ability of attraction between Ni and O atoms, and then led to Ni atoms show stronger diffusion driving force toward particle surface to contact the rich O atoms during sintering in air. However, PEG polymer can form a better barrier for more O atoms to attract Ni and Mn atoms on particle surface so that facilitated a uniform distribution. The electrochemical test indicated that the decay of discharge capacity and working voltage was mitigated, which was identified by the result of HRTEM analysis that the initial less defect structure obviously retarded the phase transformation from the layered to spinel after 50 cycles. Therefore, defects are crucial for understanding the voltage fade and capacity decay, and the improvement of performance also demonstrates that designing optimum compositions and ordering atomic arrangements will contribute to stabilize the surface structure and restrain inherent phase transitions. PMID:27116571