Solid Polymer Electrolytes-Based Composite Cathodes for Advanced Solid-State Lithium Batteries

All-solid-state lithium batteries (ASSLBs) hold immense promise as next-generation energy storage systems. A crucial aspect of ASSLB development lies in achieving high energy density, which demands the high mass loadings of cathode active material. However, thick cathode with high mass loading may introduce various challenges, such as interfacial resistance between electrolytes and electrodes, suboptimal ion conduction, and limited battery lifespan. To address these challenges, composite cathode has been engineered by integrating solid-state electrolytes into conventional cathodes to enhance ion transport. Solid polymer electrolytes (SPEs), in particular, stand out for their ability to mitigate interfacial issues during cycling due to their elasticity and flexibility compared to their inorganic counterparts. This review offers a comprehensive overview of efforts to incorporate SPEs into catholytes for ASSLBs. It begins with a discussion on catholyte composition, emphasizing the properties of their constituent components. Subsequently, it provides a concise overview of electrochemical transport and measurement techniques. The review then delves into efficient and cost-effective fabrication processes, highlighting their significance. Finally, it underscores the crucial role of SPEs in advancing the development of catholytes for the future.