Understanding and mitigating filament formation, short-circuit and solid electrolyte fracture is necessary for advanced all-solid-state batteries. Here, we employ a coupled far-field high-energy diffraction microscopy and tomography approach for assessing the chemo-mechanical behaviour for dense, polycrystalline garnet (Li₇La₃Zr₂O₁₂) solid electrolytes with grain-level resolution. In situ monitoring of grain-level stress responses reveals that the failure mechanism is stochastic and affected by local microstructural heterogeneity. Coupling high-energy X-ray diffraction and far-field high-energy diffraction microscopy measurements reveals the presence of phase heterogeneity that can alter local chemo-mechanics within the bulk solid electrolyte. These local regions are proposed to be regions with the presence of a cubic polymorph of LLZO, potentially arising from local dopant concentration variation. The coupled tomography and FF-HEDM experiments are combined with transport and mechanics modelling to illustrate the degradation of polycrystalline garnet solid electrolytes. The results showcase the pathways for processing high-performing solid-state batteries.

了解和减轻细丝形成、短路和固体电解质断裂对于先进的全固态电池来说是必要的。在这里，我们采用耦合的远场高能衍射显微镜和层析成像方法来评估致密多晶石榴石 (Li ₇ La ₃ Zr ₂ O ₁₂) 具有颗粒级分辨率的固体电解质。对晶粒级应力响应的原位监测表明，失效机制是随机的，并受局部微观结构异质性的影响。耦合高能 X 射线衍射和远场高能衍射显微镜测量揭示了相异质性的存在，它可以改变块状固体电解质内的局部化学力学。这些局部区域被认为是存在 LLZO 立方多晶型物的区域，可能由局部掺杂剂浓度变化引起。耦合断层扫描和 FF-HEDM 实验与传输和力学建模相结合，以说明多晶石榴石固体电解质的降解。结果展示了加工高性能固态电池的途径。