Pressure Effects and Countermeasures in Solid‐State Batteries: A Comprehensive Review

Abstract Solid‐state batteries (SSBs) have garnered significant attention as promising and safe electrochemical solutions for high‐energy storage. Despite their advantageous characteristics, the widespread adoption of SSBs encounters significant obstacles. Foremost among these challenges is the inadequate solid‐state electrolyte (SSE)‐electrode contact, particularly under typical operating conditions with moderate pressures. Consequently, substantial external pressures are conventionally applied to establish a tightly bonded and low‐impedance interfacial connection. Unfortunately, high pressure concurrently precipitates detrimental effects, such as SSE structural fractures and premature short circuits. Moreover, the pressure parameters that are currently employed in laboratory‐scale research lack consistency and far exceed the current industrial requirement (< 1 MPa), which undermines the objective evaluation of SSBs’ actual performance and hampers the practical utilization. This review aims to construct a comprehensive perspective on the effect of pressure on SSBs, with a specific focus on decoupling the interfacial/bulk electrochemo‐mechanical dynamics. In particular, the adverse consequences and fundamental causes of the highly‐pressure‐reliance behavior in SSBs are scrutinized, followed by a systematic summarization of the current strategies toward low‐pressure SSBs. Based on these insights, it is put forth promising directions for better disentangling the electrochemo‐mechanical interplay within SSBs and inspiring the development of pressure‐independent SSBs.