A free volume-based analytical model for plastic flow in thin-walled silicon structures of lithium-ion batteries
A free volume-based analytical model for plastic flow in thin-walled silicon structures of lithium-ion batteries
复制标题
基于自由体积的锂离子电池薄壁硅结构塑性流动分析模型
DOI：
10.1007/s00707-021-03121-2
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发表时间：
2022
期刊：
影响因子：
2.7
通讯作者：
Fuqian Yang
中科院分区：
文献类型：
--
作者：
Kai Zhang;Yong Li;Bailin Zheng;Fuqian Yang
认识到基于物理的本构模型可以提供对非晶硅在渗锂过程中的塑性变形的洞察，我们利用自由体积理论建立了基于物理的本构模型，并研究了包括硅薄膜、薄壁中空纳米颗粒和纳米管在内的薄壁硅阳极中的塑性流动。得到了三种薄壁阳极结构的应力场的解析解，其中硅薄膜的面内应力的分析结果与文献报道的实验数据吻合较好，表明该模型在分析硅基阳极的锂离子诱导应力方面是适用的。进一步的分析表明，三种薄壁结构的应力和自由体积都随着荷电状态(SOC)的增加而减小。空心纳米颗粒和纳米管中应力的时空变化非常相似。由于薄壁结构，两种结构的应力场的三个分量几乎是一致的。沿环箍方向的应力比其他两个方向的应力大，这表明环向表面裂纹很可能最先发生。在准静态下，应力和自由体积随充注率的增加而增大，表明塑性流动阻力随充注率的增加而减弱。
Realizing that physically based constitutive models can provide insight into the plastic deformation of amorphous silicon during lithiation, we establish a physically based constitutive model with the free volume theory and investigate the plastic flow in thin-walled silicon anodes, including silicon thin film, thin-walled hollow nanoparticle and nanotube. Analytical solutions of stress fields in the three thin-walled anode structures are obtained, and the analytical result of the in-plane stress in a silicon thin film is in good accord with the experimental data reported in the literature, suggesting the applicability of this model in the analysis of lithiation-induced stress in silicon-based anodes. Further analyses show that for all the three thin-walled structures the stress and free volume decrease with the increase in the state of charge (SOC). The spatiotemporal variations of the stresses in the hollow nanoparticle and nanotube are very similar to each other. The three components of the stress field in both structures are nearly uniform due to thin-walled structures. The stress along the hoop direction is larger than the other two, which indicates that circumferential surface cracks are likely to occur first. At the quasi-static state, the stresses and free volume increase with increasing the charging rate, indicating that the resistance to plastic flow fades with the increase in the C-rate.