共查询到20条相似文献,搜索用时 15 毫秒
1.
Fluorinated Polyimide as a Novel High‐Voltage Binder for High‐Capacity Cathode of Lithium‐Ion Batteries 下载免费PDF全文
An increase in the energy density of lithium‐ion batteries has long been a competitive advantage for advanced wireless devices and long‐driving electric vehicles. Li‐rich layered oxide, xLi2MnO3?(1?x)LiMn1?y?zNiyCozO2, is a promising high‐capacity cathode material for high‐energy batteries, whose capacity increases by increasing charge voltage to above 4.6 V versus Li. Li‐rich layered oxide cathode however suffers from a rapid capacity fade during the high‐voltage cycling because of instable cathode–electrolyte interface, and the occurrence of metal dissolution, particle cracking, and structural degradation, particularly, at elevated temperatures. Herein, this study reports the development of fluorinated polyimide as a novel high‐voltage binder, which mitigates the cathode degradation problems through superior binding ability to conventional polyvinylidenefluoride binder and the formation of robust surface structure at the cathode. A full‐cell consisting of fluorinated polyimide binder‐assisted Li‐rich layered oxide cathode and conventional electrolyte without any electrolyte additive exhibits significantly improved capacity retention to 89% at the 100th cycle and discharge capacity to 223–198 mA h g?1 even under the harsh condition of 55 °C and high charge voltage of 4.7 V, in contrast to a rapid performance fade of the cathode coated with polyvinylidenefluoride binder. 相似文献
2.
Understanding the Origin of Li2MnO3 Activation in Li‐Rich Cathode Materials for Lithium‐Ion Batteries 下载免费PDF全文
Delai Ye Guang Zeng Kazuhiro Nogita Kiyoshi Ozawa Marlies Hankel Debra J. Searles Lianzhou Wang 《Advanced functional materials》2015,25(48):7488-7496
Li‐rich layered cathode materials have been considered as a family of promising high‐energy density cathode materials for next generation lithium‐ion batteries (LIBs). However, although activation of the Li2MnO3 phase is known to play an essential role in providing superior capacity, the mechanism of activation of the Li2MnO3 phase in Li‐rich cathode materials is still not fully understood. In this work, an interesting Li‐rich cathode material Li1.87Mn0.94Ni0.19O3 is reported where the Li2MnO3 phase activation process can be effectively controlled due to the relatively low level of Ni doping. Such a unique feature offers the possibility of investigating the detailed activation mechanism by examining the intermediate states and phases of the Li2MnO3 during the controlled activation process. Combining powerful synchrotron in situ X‐ray diffraction analysis and observations using advanced scanning transmission electron microscopy equipped with a high angle annular dark field detector, it has been revealed that the subreaction of O2 generation may feature a much faster kinetics than the transition metal diffusion during the Li2MnO3 activation process, indicating that the latter plays a crucial role in determining the Li2MnO3 activation rate and leading to the unusual stepwise capacity increase over charging cycles. 相似文献
3.
4.
Qingyuan Li Dong Zhou Lijuan Zhang De Ning Zhenhua Chen Zijian Xu Rui Gao Xinzhi Liu Donghao Xie Gerhard Schumacher Xiangfeng Liu 《Advanced functional materials》2019,29(10)
When fabricating Li‐rich layered oxide cathode materials, anionic redox chemistry plays a critical role in achieving a large specific capacity. Unfortunately, the release of lattice oxygen at the surface impedes the reversibility of the anionic redox reaction, which induces a large irreversible capacity loss, inferior thermal stability, and voltage decay. Therefore, methods for improving the anionic redox constitute a major challenge for the application of high‐energy‐density Li‐rich Mn‐based cathode materials. Herein, to enhance the oxygen redox activity and reversibility in Co‐free Li‐rich Mn‐based Li1.2Mn0.6Ni0.2O2 cathode materials by using an integrated strategy of Li2SnO3 coating‐induced Sn doping and spinel phase formation during synchronous lithiation is proposed. As an Li+ conductor, a Li2SnO3 nanocoating layer protects the lattice oxygen from exposure at the surface, thereby avoiding irreversible oxidation. The synergy of the formed spinel phase and Sn dopant not only improves the anionic redox activity, reversibility, and Li+ migration rate but also decreases Li/Ni mixing. The 1% Li2SnO3‐coated Li1.2Mn0.6Ni0.2O2 delivers a capacity of more than 300 mAh g?1 with 92% Coulombic efficiency. Moreover, improved thermal stability and voltage retention are also observed. This synergic strategy may provide insights for understanding and designing new high‐performance materials with enhanced reversible anionic redox and stabilized surface lattice oxygen. 相似文献
5.
Moonsu Yoon Yanhao Dong Youngbin Yoo Seungjun Myeong Jaeseong Hwang Junhyeok Kim Seong‐Hyeon Choi Jaekyung Sung Seok Ju Kang Ju Li Jaephil Cho 《Advanced functional materials》2020,30(6)
A practical solution is presented to increase the stability of 4.45 V LiCoO2 via high‐temperature Ni doping, without adding any extra synthesis step or cost. How a putative uniform bulk doping with highly soluble elements can profoundly modify the surface chemistry and structural stability is identified from systematic chemical and microstructural analyses. This modification has an electronic origin, where surface‐oxygen‐loss induced Co reduction that favors the tetrahedral site and causes damaging spinel phase formation is replaced by Ni reduction that favors octahedral site and creates a better cation‐mixed structure. The findings of this study point to previously unspecified surface effects on the electrochemical performance of battery electrode materials hidden behind an extensively practiced bulk doping strategy. The new understanding of complex surface chemistry is expected to help develop higher‐energy‐density cathode materials for rechargeable batteries. 相似文献
6.
7.
Biao Li Ruiwen Shao Huijun Yan Li An Bin Zhang Hang Wei Jin Ma Dingguo Xia Xiaodong Han 《Advanced functional materials》2016,26(9):1330-1337
Lithium‐rich layered oxides are considered as promising cathode materials for Li‐ion batteries with high energy density due to their higher capacity as compared with the conventional LiMO2 (e.g., LiCoO2, LiNiO2, and LiNi1/3Co1/3Mn1/3O2) layered oxides. However, why lithium‐rich layered oxides exhibit high capacities without undergoing a structural collapse for a certain number of cycles has attracted limited attention. Here, based on the model of Li2RuO3, it is uncovered that the mechanism responsible for the structural integrity shown by lithium‐rich layered oxides is realized by the flexible local structure due to the presence of lithium atoms in the transition metal layer, which favors the formation of O22?‐like species, with the aid of in situ extended X‐ray absorption fine structure (EXAFS), in situ energy loss spectroscopy (EELS), and density functional theory (DFT) calculation. This finding will open new scope for the development of high‐capacity layered electrodes. 相似文献
8.
Huiping Yang Hong‐Hui Wu Mingyuan Ge Lingjun Li Yifei Yuan Qi Yao Jie Chen Lingfeng Xia Jiangming Zheng Zhaoyong Chen Junfei Duan Kim Kisslinger Xiao Cheng Zeng Wah‐Keat Lee Qiaobao Zhang Jun Lu 《Advanced functional materials》2019,29(13)
A critical challenge in the commercialization of layer‐structured Ni‐rich materials is the fast capacity drop and voltage fading due to the interfacial instability and bulk structural degradation of the cathodes during battery operation. Herein, with the guidance of theoretical calculations of migration energy difference between La and Ti from the surface to the inside of LiNi0.8Co0.1Mn0.1O2, for the first time, Ti‐doped and La4NiLiO8‐coated LiNi0.8Co0.1Mn0.1O2 cathodes are rationally designed and prepared, via a simple and convenient dual‐modification strategy of synchronous synthesis and in situ modification. Impressively, the dual modified materials show remarkably improved electrochemical performance and largely suppressed voltage fading, even under exertive operational conditions at elevated temperature and under extended cutoff voltage. Further studies reveal that the nanoscale structural degradation on material surfaces and the appearance of intergranular cracks associated with the inconsistent evolution of structural degradation at the particle level can be effectively suppressed by the synergetic effect of the conductive La4NiLiO8 coating layer and the strong Ti? O bond. The present work demonstrates that our strategy can simultaneously address the two issues with respect to interfacial instability and bulk structural degradation, and it represents a significant progress in the development of advanced cathode materials for high‐performance lithium‐ion batteries. 相似文献
9.
Moon Young Yang Sangryun Kim Kyungsu Kim Woosuk Cho Jang Wook Choi Yoon Sung Nam 《Advanced functional materials》2017,27(35)
Li‐rich layered oxide materials are promising candidates for high‐energy Li‐ion batteries. They show high capacities of over 200 mAh g?1 with the additional occupation of Li in their transition metal layers; however, the poor cycle performance induced by an irreversible phase transition limits their use in practical applications. In recent work, an atomic‐scale modified surface, in which Ni is ordered at 2c sites in the Li layers, significantly improves the performance in terms of reversible capacity and cycling stability. The role of the incorporated Ni on this performance, however, is not yet clearly understood. Here, the effects of the ordered Ni on Li battery performance are presented, based on first‐principles calculations and experimental observations. The Ni substitution suppresses the oxygen loss by moderating the oxidation of oxygen ions during the delithiation process and forms bonds with adjacent oxygen after the first deintercalation of Li ions. These Ni? O bonds contribute to the formation of a solid surface, resulting in the improved cycling stability. Moreover, the multivalent Ni suppresses Mn migration to the Li‐sites that causes the undesired phase transition. These findings from theoretical calculations and experimental observations provide insights to enhance the electrochemical performance of Li‐rich layered oxides. 相似文献
10.
Microstructure Evolution of Concentration Gradient Li[Ni0.75Co0.10Mn0.15]O2 Cathode for Lithium‐Ion Batteries 下载免费PDF全文
Chong S. Yoon Suk Jun Kim Un‐Hyuck Kim Kang‐Joon Park Hoon‐Hee Ryu Hee‐Soo Kim Yang‐Kook Sun 《Advanced functional materials》2018,28(28)
Detailed analysis of the microstructural changes during lithiation of a full‐concentration‐gradient (FCG) cathode with an average composition of Li[Ni0.75Co0.10Mn0.15]O2 is performed starting from its hydroxide precursor, FCG [Ni0.75Co0.10Mn0.15](OH)2 prior to lithiation. Transmission electron microscopy (TEM) reveals that a unique rod‐shaped primary particle morphology and radial crystallographic texture are present in the prelithiation stage. In addition, TEM detected a two‐phase structure consisting of MnOOH and Ni(OH)2, and crystallographic twins of MnOOH on the Mn‐rich precursor surface. The formation of numerous twins is driven by the lattice mismatch between MnOOH and Ni(OH)2. Furthermore, the twins persist in the lithiated cathode; however, their density decrease with increasing lithiation temperature. Cation disordering, which influences cathode performance, is observed to continuously decrease with increasing lithiation temperature with a minimum observed at 790 °C. Consequently, lithiation at 790 °C (for 10 h) produced optimal discharge capacity and cycling stability. Above 790 °C, an increase in cation disordering and excessive coarsening of the primary particles lead to the deterioration of electrochemical properties. The twins in the FCG cathode precursor may promote the optimal primary particle morphology by retarding the random coalescence of primary particles during lithiation, effectively preserving both the morphology and crystallographic texture of the precursor. 相似文献
11.
Yuwei Mao Xuelong Wang Sihao Xia Kai Zhang Chenxi Wei Seongmin Bak Zulipiya Shadike Xuejun Liu Yang Yang Rong Xu Piero Pianetta Stefano Ermon Eli Stavitski Kejie Zhao Zhengrui Xu Feng Lin Xiao‐Qing Yang Enyuan Hu Yijin Liu 《Advanced functional materials》2019,29(18)
Nickel‐rich layered materials LiNi1‐x‐yMnxCoyO2 are promising candidates for high‐energy‐density lithium‐ion battery cathodes. Unfortunately, they suffer from capacity fading upon cycling, especially with high‐voltage charging. It is critical to have a mechanistic understanding of such fade. Herein, synchrotron‐based techniques (including scattering, spectroscopy, and microcopy) and finite element analysis are utilized to understand the LiNi0.6Mn0.2Co0.2O2 material from structural, chemical, morphological, and mechanical points of view. The lattice structural changes are shown to be relatively reversible during cycling, even when 4.9 V charging is applied. However, local disorder and strain are induced by high‐voltage charging. Nano‐resolution 3D transmission X‐ray microscopy data analyzed by machine learning methodology reveal that high‐voltage charging induced significant oxidation state inhomogeneities in the cycled particles. Regions at the surface have a rock salt–type structure with lower oxidation state and build up the impedance, while regions with higher oxidization state are scattered in the bulk and are likely deactivated during cycling. In addition, the development of micro‐cracks is highly dependent on the pristine state morphology and cycling conditions. Hollow particles seem to be more robust against stress‐induced cracks than the solid ones, suggesting that morphology engineering can be effective in mitigating the crack problem in these materials. 相似文献
12.
Min Liu Nanping Deng Jingge Ju Lanlan Fan Liyuan Wang Zongjie Li Huijuan Zhao Guang Yang Weimin Kang Jing Yan Bowen Cheng 《Advanced functional materials》2019,29(49)
Lithium‐sulfur (Li‐S) batteries are in the spotlight because their outstanding theoretical specific energy is much higher than those of the commercial lithium ion (Li‐ion) batteries. Li‐S batteries are tough competitors for future‐developing energy storage in the fields of portable electronics and electric vehicles. However, the severe “shuttle effect” of the polysulfides and the serious damage of lithium dendrites are main factors blocking commercial production of Li‐S batteries. Owing to their superior nanostructure, electrospun nanofiber materials commonly show some unique characteristics that can simultaneously resolve these issues. So far, various novel cathodes, separators, and interlayers of electrospun nanofiber materials which are applied to resolve these challenges are researched. This review presents the fundamental research and technological development of multifarious electrospun nanofiber materials for Li‐S cells, including their processing methods, structures, morphology engineering, and electrochemical performance. Not only does the review article contain a summary of electrospun nanofiber materials in Li‐S batteries but also a proposal for designing electrospun nanofiber materials for Li‐S cells. These systematic discussions and proposed directions can enlighten thoughts and offer ways in the reasonable design of electrospun nanofiber materials for excellent Li‐S batteries in the near future. 相似文献
13.
Nitrogen‐Doped Mesoporous Carbon Promoted Chemical Adsorption of Sulfur and Fabrication of High‐Areal‐Capacity Sulfur Cathode with Exceptional Cycling Stability for Lithium‐Sulfur Batteries 下载免费PDF全文
Jiangxuan Song Terrence Xu Mikhail L. Gordin Pengyu Zhu Dongping Lv Ying‐Bing Jiang Yongsheng Chen Yuhua Duan Donghai Wang 《Advanced functional materials》2014,24(9):1243-1250
As one important component of sulfur cathodes, the carbon host plays a key role in the electrochemical performance of lithium‐sulfur (Li‐S) batteries. In this paper, a mesoporous nitrogen‐doped carbon (MPNC)‐sulfur nanocomposite is reported as a novel cathode for advanced Li‐S batteries. The nitrogen doping in the MPNC material can effectively promote chemical adsorption between sulfur atoms and oxygen functional groups on the carbon, as verified by X‐ray absorption near edge structure spectroscopy, and the mechanism by which nitrogen enables the behavior is further revealed by density functional theory calculations. Based on the advantages of the porous structure and nitrogen doping, the MPNC‐sulfur cathodes show excellent cycling stability (95% retention within 100 cycles) at a high current density of 0.7 mAh cm‐2 with a high sulfur loading (4.2 mg S cm‐2) and a sulfur content (70 wt%). A high areal capacity (≈3.3 mAh cm‐2) is demonstrated by using the novel cathode, which is crucial for the practical application of Li‐S batteries. It is believed that the important role of nitrogen doping promoted chemical adsorption can be extended for development of other high performance carbon‐sulfur composite cathodes for Li‐S batteries. 相似文献
14.
Batteries: A New Strategy to Effectively Suppress the Initial Capacity Fading of Iron Oxides by Reacting with LiBH4 (Adv. Funct. Mater. 16/2017) 下载免费PDF全文
Yun Cao Yaxiong Yang Zhuanghe Ren Ni Jian Mingxia Gao Yongjun Wu Min Zhu Feng Pan Yongfeng Liu Hongge Pan 《Advanced functional materials》2017,27(16)
15.
Onur Buyukcakir Jaegeon Ryu Se Hun Joo Jieun Kang Recep Yuksel Jiyun Lee Yi Jiang Sungho Choi Sun Hwa Lee Sang Kyu Kwak Soojin Park Rodney S. Ruoff 《Advanced functional materials》2020,30(36)
The synthesis of a new type of redox‐active covalent triazine framework (rCTF) material, which is promising as an anode for Li‐ion batteries, is reported. After activation, it has a capacity up to ≈1190 mAh g?1 at 0.5C with a current density of 300 mA g?1 and a high cycling stability of over 1000 discharge/charge cycles with a stable Coulombic efficiency in an rCTF/Li half‐cell. This rCTF has a high rate performance, and at a charging rate of 20C with a current density of 12 A g?1 and it functions well for over 1000 discharge/charge cycles with a reversible capacity of over 500 mAh g?1. By electrochemical analysis and theoretical calculations, it is found that its lithium‐storage mechanism involves multi‐electron redox‐reactions at anthraquinone, triazine, and benzene rings by the accommodation of Li. The structural features and progressively increased structural disorder of the rCTF increase the kinetics of infiltration and significantly shortens the activation period, yielding fast‐charging Li‐ion half and full cells even at a high capacity loading. 相似文献
16.
A Family of High‐Performance Cathode Materials for Na‐ion Batteries,Na3(VO1−xPO4)2 F1+2x (0 ≤ x ≤ 1): Combined First‐Principles and Experimental Study 下载免费PDF全文
Young‐Uk Park Dong‐Hwa Seo Hyungsub Kim Jongsoon Kim Seongsu Lee Byoungkook Kim Kisuk Kang 《Advanced functional materials》2014,24(29):4603-4614
Room‐temperature Na‐ion batteries (NIBs) have recently attracted attention as potential alternatives to current Li‐ion batteries (LIBs). The natural abundance of sodium and the similarity between the electrochemical properties of NIBs and LIBs make NIBs well suited for applications requiring low cost and long‐term reliability. Here, the first successful synthesis of a series of Na3(VO1?x PO4)2F1+2x (0 ≤ x ≤ 1) compounds as a new family of high‐performance cathode materials for NIBs is reported. The Na3(VO1?x PO4)2F1+2x series can function as high‐performance cathodes for NIBs with high energy density and good cycle life, although the redox mechanism varies depending on the composition. The combined first‐principles calculations and experimental analysis reveal the detailed structural and electrochemical mechanisms of the various compositions in solid solutions of Na3(VOPO4)2F and Na3V2(PO4)2F3. The comparative data for the Na y (VO1?x PO4)2F1+2x electrodes show a clear relationship among V3+/V4+/V5+ redox reactions, Na+?Na+ interactions, and Na+ intercalation mechanisms in NIBs. The new family of high‐energy cathode materials reported here is expected to spur the development of low‐cost, high‐performance NIBs. 相似文献
17.
Synchronous Tailoring Surface Structure and Chemical Composition of Li‐Rich–Layered Oxide for High‐Energy Lithium‐Ion Batteries 下载免费PDF全文
Bing Wu Xiukang Yang Xia Jiang Yi Zhang Hongbo Shu Ping Gao Li Liu Xianyou Wang 《Advanced functional materials》2018,28(37)
Li‐rich–layered oxide is considered to be one of the most promising cathode materials for high‐energy lithium ion batteries. However, it suffers from poor rate capability, capacity loss, and voltage decay upon cycling that limits its utilization in practical applications. Surface properties of Li‐rich–layered oxide play a critical role in the function of batteries. Herein, a novel and successful strategy for synchronous tailoring surface structure and chemical composition of Li‐rich–layered oxide is proposed. Poor nickel content on the surface of carbonate precursor is initially prepared by a facile treatment of NH3·H2O, which can retain at a certain low amount on the surface in the final lithiated Li‐rich–layered oxide after a solid‐phase reaction process. Moreover, a phase‐gradient outer layer with “layered‐coexisting phase‐spinel” structure toward to the outside surface is self‐induced and formed synchronously based on poor nickel surface of the precursor. Electrochemical tests reveal this unique surface enables excellent cycling stability, improved rate capability, and slight voltage decay of cathodes. The finding here sheds light on a universal principle both for masterly tailoring surface structure and chemical composition at the same time for improving electrochemical performance of electrode materials. 相似文献
18.
Self‐Sacrifice Template Fabrication of Hierarchical Mesoporous Bi‐Component‐Active ZnO/ZnFe2O4 Sub‐Microcubes as Superior Anode Towards High‐Performance Lithium‐Ion Battery 下载免费PDF全文
Linrui Hou Lin Lian Longhai Zhang Gang Pang Changzhou Yuan Xiaogang Zhang 《Advanced functional materials》2015,25(2):238-246
In the work, a facile yet efficient self‐sacrifice strategy is smartly developed to scalably fabricate hierarchical mesoporous bi‐component‐active ZnO/ZnFe2O4 (ZZFO) sub‐microcubes (SMCs) by calcination of single‐resource Prussian blue analogue of Zn3[Fe(CN)6]2 cubes. The hybrid ZZFO SCMs are homogeneously constructed from well‐dispersed nanocrstalline ZnO and ZnFe2O4 (ZFO) subunites at the nanoscale. After selectively etching of ZnO nanodomains from the hybrid, porously assembled ZFO SMCs with integrate architecture are obtained accordingly. When evaluated as anodes for LIBs, both hybrid ZZFO and ZFO samples exhibit appealing electrochemical performance. However, the as‐synthesized ZZFO SMCs demonstrate even better electrochemical Li‐storage performance, including even larger initial discharge capacity and reversible capacity, higher rate behavior and better cycling performance, particularly at high rates, compared with the single ZFO, which should be attributed to its unique microstructure characteristics and striking synergistic effect between the bi‐component‐active, well‐dispersed ZnO and ZFO nanophases. Of great significance, light is shed upon the insights into the correlation between the electrochemical Li‐storage property and the structure/component of the hybrid ZZFO SMCs, thus, it is strongly envisioned that the elegant design concept of the hybrid holds great promise for the efficient synthesis of advanced yet low‐cost anodes for next‐generation rechargeable Li‐ion batteries. 相似文献
19.
Co3O4 nanotubes, nanorods, and nanoparticles are used as the anode materials of lithium‐ion batteries. The results show that the Co3O4 nanotubes prepared by a porous‐alumina‐template method display high discharge capacity and superior cycling reversibility. Furthermore, Co3O4 nanotubes exhibit excellent sensitivity to hydrogen and alcohol, owing to their hollow, nanostructured character. 相似文献
20.
CoFe–Cl Layered Double Hydroxide: A New Cathode Material for High‐Performance Chloride Ion Batteries
Qing Yin Deming Rao Guanjun Zhang Yajun Zhao Jingbin Han Kun Lin Lirong Zheng Jian Zhang Jisheng Zhou Min Wei 《Advanced functional materials》2019,29(36)
Chloride ion batteries (CIBs) are regarded as promising energy storage systems due to their large theoretical volumetric energy density, high abundance, and low cost of chloride resources. Herein, the synthesis of CoFe layered double hydroxide in the chloride form (CoFe–Cl LDH), for use as a new cathode material for CIBs, is demonstrated for the first time. The CoFe–Cl LDH exhibits a maximum capacity of 239.3 mAh g?1 and a high reversible capacity of ≈160 mAh g?1 over 100 cycles. The superb Cl? ion storage of CoFe–Cl LDH is attributed to its unique topochemical transformation property during the charge/discharge process: a reversible intercalation/deintercalation of Cl? ions in cathode with slight expansion/contraction of basal spacing, accompanied by chemical state changes in Co2+/Co3+ and Fe2+/Fe3+ couples. First‐principles calculations reveal that CoFe–Cl LDH is an excellent Cl? ion conductor, with extremely low energy barriers (0.12?0.25 eV) for Cl? diffusion. This work opens a new avenue for LDH materials as promising cathodes for anion‐type rechargeable batteries, which are regarded as formidable competitors to traditional metal ion‐shuttling batteries. 相似文献