Plastic dissipation of high-capacity electrode materials during lithiation and de-lithiation processes
Plastic dissipation of high-capacity electrode materials during lithiation and de-lithiation processes
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DOI：
10.1007/s00707-022-03219-1
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发表时间：
2022-05
期刊：
影响因子：
2.7
通讯作者：
Xu Song;Yongjun Lu;X. Cao;Fenghui Wang;Xiang Zhao
中科院分区：
文献类型：
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作者：
Xu Song;Yongjun Lu;X. Cao;Fenghui Wang;Xiang Zhao
大容量阳极在循环过程中的塑性变形伴随着能量耗散。在某些情况下，塑性耗散可以占电极系统总能量耗散的相当大的比例。本文建立了一个包含塑性相关内变量的热力学一致的多物理场理论框架，以理解热传导、物质扩散和弹塑性机制相互作用，并评估塑性耗散。考虑了刚性衬底上薄膜结构和自由球形结构的Si、Ge和Sn阳极。介绍了相应的塑性模型和拟合参数。锂插入相关的能量流主要转化为可逆的化学能，部分能量被消耗来驱动锂扩散和塑性流动。对于薄膜电极单元，能量耗散主要取决于材料性能，锂扩散和塑性流动阻力越大，耗散越大。粗略估计，Si、Ge和Sn薄膜电极的塑性耗散分别约占总输入能量的20%、10%和5%。球形电极的能量耗散要小得多，并且很大程度上取决于运行速率和尺寸。通过结构设计，减小电极单元的特征尺寸，减少能量损失，避免能量浪费。这些工作为高容量电极材料的塑性耗散提供了有价值的见解，并为具有塑性的电极材料的多物理场建模提供了理论框架。
The plastic deformation of high-capacity anodes during cycling is accompanied by energy dissipation. In certain cases, plastic dissipation can account for a considerable proportion of the total energy dissipation of the electrode system. Herein, a thermodynamically consistent multi-physics theoretical framework containing plasticity-related internal variables is developed to understand the heat conduction, species diffusion, and elastoplasticity mechanism interactions and to evaluate plastic dissipation. Si, Ge, and Sn anodes with a thin-film configuration on a rigid substrate and a free spherical configuration are considered. The corresponding plastic models and fitting parameters are introduced. Li insertion-associated energy flow is mainly transformed into reversible chemical energy, and part of the energy is consumed to drive Li diffusion and plastic flow. For the thin-film electrode unit, the energy dissipation mainly depends on the material properties, and a higher resistance for Li diffusion and plastic flow leads to a larger energy dissipation. A rough estimate shows that the plastic dissipation of Si, Ge, and Sn thin-film electrodes accounts for around 20, 10, and 5% of the total input energy, respectively. The energy dissipation of spherical electrodes is much smaller and strongly depends on the operation rate and size. Structure design and reducing the characteristic size of the electrode units can reduce energy loss and avoid energy waste. These works offer valuable insights into the plastic dissipation of high-capacity electrode materials and provide a theoretical framework for multi-physics modelling of electrode materials with plasticity.