The unique mechanical properties and transport features of grain boundaries (GBs) in polycrystalline materials have been widely investigated. However, studies which focus on the unique chemo-mechanics phenomena resulting from GBs’ are exceedingly sparse. In this work, a thermodynamically consistent framework has been developed to explore the multi-physics coupling between mechanics and species diffusion. Constitutive laws for the bulk and the across-GB interaction laws have been derived for large deformations from the system free energies. A chemo-mechanically coupled cohesive zone model is developed which takes into account mode-dependent fracture properties in the presence of GBs. Polycrystalline ${\text{LiNi}}_x{\text{Mn}}_y{\text{Co}}_z{\text{O}}_2$ (NMC) particles and ${\text{Li}}_x{\text{V}}_2{\text{O}}_5$ nanowires haveüeen selected to demonstrate the impact of GBs on the modeled and observed chemo-mechanics. The model has been implemented in the open-source finite element (FE) package MOOSE. Simulation results indicate that the chemical process and the mechanical degradation go hand-in–hand, where enhanced intergranular chemical inhomogeneities weaken the mechanical strength of the GBs, while damage to the GBs affects or even block transport across the GB. Furthermore, experimentally observed characteristics of chemo-mechanical degradation, e.g., chemical “hot-spots” and surface layer delamination can be accurately predicted by the model.

多晶材料中晶界 (GB) 的独特机械性能和传输特征已被广泛研究。然而，专注于由 GB 引起的独特化学力学现象的研究非常稀少。在这项工作中，开发了一个热力学一致的框架来探索力学和物种扩散之间的多物理耦合。体的本构定律和跨 GB 相互作用定律已经从系统自由能的大变形推导出来。开发了一种化学-机械耦合的粘性带模型，该模型考虑了存在 GB 时与模式相关的断裂特性。多晶${\text{李妮}}_X{\text{锰}}_{是}{\text{公司}}_z{\text{哦}}_2$ (NMC) 粒子和 ${\text{李}}_X{\text{伏}}_2{\text{哦}}_5$已选择纳米线来证明 GB 对建模和观察到的化学力学的影响。该模型已在开源有限元 (FE) 包 MOOSE 中实现。模拟结果表明化学过程和机械降解是相辅相成的，其中增强的晶间化学不均匀性削弱了 GB 的机械强度，而 GB 的损坏会影响甚至阻碍了 GB 的传输。此外，该模型可以准确预测化学机械降解的实验观察特征，例如化学“热点”和表层分层。