Thermally driven mesoscale chemomechanical interplay in Li0.5Ni0.6Mn0.2Co0.2O2 cathode materials
Thermally driven mesoscale chemomechanical interplay in Li0.5Ni0.6Mn0.2Co0.2O2 cathode materials
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DOI：
10.1039/c8ta08973f
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发表时间：
2018-11
影响因子：
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通讯作者：
Chenxi Wei;Y. Zhang;Sang Jun Lee;Linqin Mu;Jin Liu;Chenxu Wang;Yang Yang-Yang;M. Doeff;P. Pianetta;D. Nordlund;Xi‐Wen Du;Yangchao Tian;K. Zhao;Jun-Sik Lee;Feng Lin;Yijin Liu
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文献类型：
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作者：
Chenxi Wei;Y. Zhang;Sang Jun Lee;Linqin Mu;Jin Liu;Chenxu Wang;Yang Yang-Yang;M. Doeff;P. Pianetta;D. Nordlund;Xi‐Wen Du;Yangchao Tian;K. Zhao;Jun-Sik Lee;Feng Lin;Yijin Liu
虽然锂离子电池旨在在温和的温度窗口内运行，但它们的结构和化学复杂性可能导致意外的局部电化学事件，这可能导致极端的温度峰值，这反过来可能引发系统中更多不期望的和复杂的反应。可视化和了解电池电极材料对热滥用条件的反应可能为预防和缓解安全危害提供知识基础。在这里，我们展示了一个全面的调查热驱动的化学机械相互作用的Li0.5Ni0.6Mn0.2Co0.2O2（充电的NMC 622）阴极材料。我们报告说，在早期阶段的热滥用，氧释放和内部锂迁移同时发生，并伴随着机械崩解在中尺度。在后期，由于锂在非层状晶格中的溶解度有限，在二次粒子表面上观察到Li突起。在升高的温度下从主体材料提取氧和锂两者可经由电子和离子扩散途径的重排、库仑效率的降低和/或引起可引起热失控的内部短路而影响电池水平的化学和安全性。
While Li ion batteries are intended to be operated within a mild temperature window, their structural and chemical complexity could lead to unanticipated local electrochemical events that could cause extreme temperature spikes, which, in turn, could trigger more undesired and sophisticated reactions in the system. Visualizing and understanding the response of battery electrode materials to thermal abuse conditions could potentially offer a knowledge basis for the prevention and mitigation of the safety hazards. Here we show a comprehensive investigation of thermally driven chemomechanical interplay in a Li0.5Ni0.6Mn0.2Co0.2O2 (charged NMC622) cathode material. We report that, at the early stage of the thermal abuse, oxygen release and internal Li migration occur concurrently, and are accompanied by mechanical disintegration at the mesoscale. At the later stage, Li protrusions are observed on the secondary particle surface due to the limited lithium solubility in non-layered lattices. The extraction of both oxygen and lithium from the host material at elevated temperature could influence the chemistry and safety at the cell level via rearrangement of the electron and ion diffusion pathways, reduction of the coulombic efficiency, and/or causing an internal short circuit that could provoke a thermal runaway.