Interfacial Failure and Self‐Healing in Solid‐State Batteries

Solid-state batteries hold great promise for simultaneously improving energy density and intrinsic safety. However, their practical application is severely impeded by interfacial instabilities arising from coupled mechanical, chemical, and electrochemical degradation during cycling, ultimately resulting in rapid performance decay. Although conventional strategies, such as interfacial coatings or electrode structural optimization, have partially improved electrochemical performance, their inherently static nature renders them ill-equipped to adapt to the continuous and dynamic evolution of interfacial damage during long-term operation. To address these persistent challenges, dynamic interfacial self-healing has emerged as a compelling strategy for developing highly durable and stable solid-state batteries. In this review, we first discuss the origins and evolution of mechanical, chemical, and electrochemical failures at the interface, highlighting their intricate interplay. Recent progress in self-healing strategies, including physical flow, chemical restoration, external stimuli, and electric fields was subsequently analyzed to solve specific interfacial failure behavior. Perspectives on the emerging strategies and key challenges for achieving high self-healing efficiency were provided in the end. The development of self-healing mechanisms presents a highly viable route toward the realization of robust, low-pressure solid-state batteries.