Abstract Although the unique mechanical and transport features of grain boundaries (GBs) in polycrystalline ion conductors have been recognized, the understanding of the chemo-mechanical interplay and its impact is insufficient. We present a coupled GB model which includes both the damage-dependent across-grain transport and a mechanical cohesive zone law. 3D simulations on LiNixMnyCozO2 demonstrate that the chemical process and the mechanical degradation go hand-in-hand: the enhanced intergranular chemical inhomogeneity challenges the GB mechanical strength, while the GB damage influences or even blocks the across-grain transport. Results explain well the experimentally observed features including chemical hot spots and surface layer delamination.

中文翻译：

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化学机械晶界模型及其在理解锂离子电池材料损伤中的应用

摘要 尽管多晶离子导体中晶界 (GBs) 的独特机械和输运特性已得到认可，但对化学-机械相互作用及其影响的理解还不够。我们提出了一个耦合 GB 模型，其中包括与损伤相关的跨晶粒传输和机械内聚区定律。LiNixMnyCozO2 的 3D 模拟表明化学过程和机械降解是齐头并进的：增强的晶间化学不均匀性挑战了 GB 机械强度，而 GB 损伤影响甚至阻止了跨晶粒传输。结果很好地解释了实验观察到的特征，包括化学热点和表层分层。