Fatigue of LiNi0.8Co0.15Al0.05O2 in commercial Li ion batteries
Fatigue of LiNi0.8Co0.15Al0.05O2 in commercial Li ion batteries
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DOI：
10.1016/j.jpowsour.2014.08.133
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发表时间：
2015-01-01
影响因子：
9.2
通讯作者：
Ehrenberg, Helmut
中科院分区：
文献类型：
--
作者：
Kleiner, Karin;Dixon, Ditty;Ehrenberg, Helmut
采用原位粉末衍射和原位Ni K边X射线吸收光谱（XAS）研究了锂离子电池正极材料LiNi0.8Co0.15Al0.05O2（LNCAO）的热降解过程。疲劳材料取自7 Ah电池，该电池在规定的耐久性条件下循环34周。同时，将电池储存在受控条件下作为参比，而不进行电化学处理。本研究中使用的疲劳LNCAO与未循环材料相比，容量损失为26% +/- 9%。在充电和放电过程中的局部和整体结构的LNCAO进行了研究，通过X射线近边结构（XANES）分析，扩展的X射线吸收精细结构（EXAFS）分析和使用Rietveld细化原位粉末衍射图案。粉末衍射和XAS都揭示了不随电化学循环而改变的另外的菱形相。此外，具有完全锂化LNCAO的晶格参数的相在高电位下仍然存在于疲劳材料中，而在非疲劳参考材料中不存在。这些相的共存所描述的LNCAO颗粒内的域，与所观察到的疲劳。(C)2014爱思唯尔有限公司版权所有。
The degradation of LiNi0.8Co0.15Al0.05O2 (LNCAO), a cathode material in lithium-ion-batteries, was studied using in situ powder diffraction and in situ Ni K edge X-ray absorption spectroscopy (XAS). The fatigued material was taken from a 7 Ah battery which was cycled for 34 weeks under defined durability conditions. Meanwhile, a cell was stored, as reference, under controlled conditions without electrochemical treatment. The fatigued LNCAO used in this study showed a capacity loss of 26% +/- 9% compared to the non-cycled material. During charge and discharge the local and the overall structure of LNCAO was investigated by X-ray near edge structure (XANES) analysis, the extended X-ray absorption fine structure (EXAFS) analysis and by using Rietveld refinement of in situ powder diffraction patterns. Both powder diffraction and XAS revealed additional, rhombohedral phases which do not change with electrochemical cycling. Moreover, a phase with the lattice parameters of fully lithiated LNCAO was still present in the fatigued material at high potentials, while it was absent in the non-fatigued reference material. The coexistence of these phases is described by domains within the LNCAO particles, in correlation with the observed fatigue. (C) 2014 Elsevier B.V. All rights reserved.