WEB Chemo-mechanical grain boundary damage model: Application to Li-ion battery materialsThursday (24.09.2020) 17:35 - 17:50 M: Modelling and Simulation 2 Part of:
Although the unique mechanical and transport features of grain boundary (GB) in polycrystalline ion conductors have been investigated separately, the study on the chemo-mechanical interplay and its impact is insufficient. We present a multiphysics GB model, which includes both the damage-dependent across-grain transport and the mechanical cohesive zone damage law. It can recapture the interaction between the chemical process and mechanical degradation. For instance, the enhanced chemical inhomogeneity across the grain boundary due to limited ion transport can lead to more prominent delamination, while the delamination in return can influence the ion transport path due to the increased transport barrier. Their interplay is essential for understanding the degradation mechanism of those materials.
One important application example of the model is the polycrystalline ion conductors including both the cathode materials and solid-state electrolyte in Lithium-ion batteries. The chemo-mechanical GB damage model is first implemented with the Finite Element method within the open-source framework MOOSE. 3D simulations were carried out for the hierarchical LiNixMnyCozO2 meat-ball structure. We demonstrate numerically the capability of the model and the unique features of the chemo-mechanical interaction at GBs. Comparison between the simulation results and the experimental data shows good agreement, particularly the observed features like chemical hot spots and surface layer delamination are well predicted.
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