Reducing diffusion induced stress in planar electrodes by plastic shakedown and cyclic plasticity of current collector
Reducing diffusion induced stress in planar electrodes by plastic shakedown and cyclic plasticity of current collector
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DOI：
10.1016/j.jpowsour.2014.04.007
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发表时间：
2014-10
影响因子：
9.2
通讯作者：
Yicheng Song;Zongzan Li;Junqian Zhang
中科院分区：
文献类型：
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作者：
Yicheng Song;Zongzan Li;Junqian Zhang
本文提出了一种通过允许集电体的塑性变形来减小扩散引起的应力并提高层状电极容量的策略。基于电极整体应力的解析式，确定了集电体的三种弹塑性行为，即纯弹性变形、塑性安定和循环塑性。提出了区分三种情况的判据。研究发现，在充放电循环中采用薄集电体并使其塑性屈服，不仅有利于容量，因为可以为活性物质提供更大的空间，而且还有利于电化学稳定性，因为活性层中的应力显着降低。与塑性安定相对应的结构设计显示出上述改进与结构安全性之间的良好平衡，而循环塑性的情况则进一步加强了改进。因此，前者按塑性安定准则进行结构设计，后者按Coffin-Manson与期望循环寿命的关系进行结构设计。
This paper proposes a strategy to reduce the diffusion induced stress and enhance the capacity of a layered electrode by allowing the plastic deformation of current collector. Based on analytical formulations of the stress in whole electrode, three types of elastoplastic behaviors of current collector, i.e. pure elastic deformation, plastic shakedown and cyclic plasticity, are identified. Criterions separating the three cases are proposed. It is found applying a thin current collector and allowing it to plastically yield in the charge/discharge cycles is beneficial not only to capacity as more space can be provided for active materials but also to electrochemical stability because the stress in active layer is significantly reduced. Structural design corresponding to plastic shakedown shows good balance between the said improvements and structural safety, whereas the case of cyclic plasticity further enhances the improvements. Therefore, structural designing scheme is provided for the former case according to the criterion of plastic shakedown but for the latter one based on the Coffin–Manson relation with expected cycle life.