Role of intergranular constraints on cracking and failure in All Solid-State Batteries

Solid-state batteries (SSBs) hold enormous promise over traditional batteries with liquid electrolytes, primarily due to the ability to exploit the use of metallic Li as an anode, which can greatly improve cell capacity. However, instabilities in SSBs emanating from the Li metal | solid electrolyte interface currently hinder the long term cyclability of SSBs. The major cause of failure in SSBs is the nucleation and growth of cracks into the SSE, which when filled with metallic Li cause a short circuit. So far, there is a lack of chemo-mechanical understanding of what drives these cracks, and how they are filled with metallic Li. We propose to use 3D-XRD at the sub-grain scale to understand the role of microstructure, and intra-and inter granular stresses in the SSE close to the interface to develop an understanding of the underlying mechanisms that govern the (i) propagation of cracks in the SSE and (ii) filling of the cracks with metallic Li.