Heterogeneous Reinforcements to Mitigate Li Penetration through Solid Electrolytes in All‐Solid‐State Batteries

Abstract

AbstractDendrite growth is one of the leading factors that cause cycling deterioration for all‐solid‐state batteries (ASSBs). However, using a single dominant material to form the solid electrolyte has encountered several setbacks due to the intrinsically competing factors in mechanics and electrochemistry. Inspired by the “brick‐and‐mortar” structure, a strategy of embedding heterogeneous blocks (HBs) within the solid electrolyte (SE) is proposed to mitigate and suppress dendrite growth‐induced internal short circuits (ISCs). A phase‐field‐based multiphysics model is established to describe the dendrite growth behavior. Results reveal that the characteristic length ratio e between the HBs and SE is the governing factor that dominates the dendrite growth path. The results show that a single long HB and multiple HBs in medium length with specific layouts can suppress and divert dendrite growth and avoid ISCs completely. For short HB cases, HBs can delay the ISC to a certain extent. The results imply that adding an appropriately designed heterogeneous layer into the SE will effectively block dendrites, and also define desired mechanical property domains. This work provides a multiphysics mechanistic understanding of the dendrite growth and SE cracking and opens new perspectives for the material selection and structural design of SEs for long lifecycle ASSBs.