The Pursuit for High Power Density in Silicon‐Based ASSBs: Insights Into Limitations and Perspectives

Abstract All‐solid‐state batteries (ASSBs) with silicon‐based anodes are emerging as a viable energy storage system compared to conventional lithium‐ion batteries (LIBs) due to 1) the use of nonflammable solid electrolytes that not only suppress solvent‐induced parasitic reactions and volume expansion of silicon (Si) but also enhance overall safety and energy density. 2) a solid‐state charge–discharge pathway with solvent‐free interphases that reduces concentration polarization and enhances the interfacial stability. However, substantial research limitations impede their extensive application in fast‐charging devices, especially in balancing the energy and power density of ASSBs. Although strategies such as nanostructured Si, composite designs, and interfacial engineering have improved energy density and cycle life, achieving high power density remains a challenge, limiting the fast‐charging capability of Si‐based ASSBs. In this perspective article, the specific challenges are aimed to address, which are related to the limiting factors at both material and electrode levels for achieving high power density in Si‐based ASSBs. It is anticipated that this perspective will offer valuable insights into the various influencing factors, failure mechanisms, and advanced optimization strategies for achieving high‐rate retention and power density in next‐generation Si‐based ASSBs operating under low stack pressure, thus helping to bridge the gap between fundamental research and practical applications.