材料科学
锂(药物)
粒子(生态学)
相界
压力(语言学)
复合材料
相(物质)
圆筒应力
变形(气象学)
极限抗拉强度
化学
地质学
内分泌学
哲学
有机化学
海洋学
医学
语言学
作者
Shan Huang,Fenliang Fan,Ju Li,Sheng Zhang,Ting Zhu
出处
期刊:Acta Materialia
[Elsevier]
日期:2013-07-01
卷期号:61 (12): 4354-4364
被引量:182
标识
DOI:10.1016/j.actamat.2013.04.007
摘要
A model is developed to study the stress generation in a spherical particle subjected to lithium insertion. The model accounts for both the plastic deformation and the coexistence of lithium-poor and lithium-rich phases with a sharp and curved phase boundary. Such two-phase and inelastic deformation characteristics often arise during lithiation of crystalline particles with high capacity. A flexible sigmoid function is used to create the lithium profile with a step-like change in lithium concentration, mimicking a sharp phase boundary that separates a pristine core and a lithiated shell in the particle. The mechanics results, obtained by an analytic formulation and finite difference calculations, show the development of tensile hoop stress in the surface layer of the lithiated shell. This hoop tension provides the driving force of surface cracking, as observed by in situ transmission electron microscopy. The two-phase lithiation model is further compared with the single-phase one, which assumes a gradual and smooth variation in radial lithium distributions, and thus predicts only hoop compression in the surface layer of the particle. Furthermore, the effect of dilatational vs. unidirectional lithiation strains in the two-phase model is studied, thereby underscoring the critical role of anisotropy of lithiation strain in controlling stress generation in high-capacity electrodes for lithium ion batteries.
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