Electrochemical–Mechanical Evolution of Dendrites and Cracks in Na3Zr2Si2PO12 Ceramic Solid Electrolytes

Abstract The dendrite problem significantly curtails the development of all‐solid‐state batteries. Dendrite growth causes damage to solid‐state electrolytes (SSEs), ultimately leading to short‐circuiting. However, the dendrite penetration mechanism and the related electrochemical–mechanical degradation remain unclear. In this study, an electrochemical–morphological in situ observation platform is built to investigate the coupled electrochemical–mechanical evolution of dendrites and cracks in Na 3 Zr 2 Si 2 PO 12 SSEs. The operando optical observation and computer tomography technology (micro‐CT) reveal the mutual relationship between dendrite penetration and crack propagation. It is shown that the creeping stress of dendrites depends on localized current density, which dramatically influences the crack‐propagation process. Moreover, the ablation of dendrites is visually observed and discussed. Furthermore, an multi‐physics model is developed to visualize the damage, displacement, and stress distribution accompanied by the crack propagation. Combining with the results of in situ micro‐CT and cross‐section polisher, this study shows that the deflection of cracks is due to the release of creeping stress. It is further established that reducing the creeping stress of dendrites and improving the interfacial ionic transportation are effective strategies for dendrite suppression.