Recent developments in addressing the challenges associated with polymer-based solid-state lithium–sulfur batteries

Lithium–sulfur batteries (LSBs) have undergone extensive research and development in the past two decades owing to their exceptional theoretical energy density. Nevertheless, they continue to encounter critical challenges, such as polysulfide dissolution, the shuttle effect, and lithium dendrite formation in conventional liquid electrolyte (LE) systems. These issues contribute to rapid capacity decay and heightened risks of internal short circuits, hindering their practical applications. Polymer-based solid-state LSBs (PSSLSBs), which utilize solid-state electrolytes instead of flammable LEs, are considered an optimal alternative for pursuing a dependable strategy. They can fundamentally mitigate the issues of the shuttle effect and flammable risk, thereby enhancing cycling stability and safety. Insight into the recent research progress on PSSLSBs reveals that four primary components must be considered: solid-state electrolytes, S cathodes, Li anodes, and the interface. In this review, we summarize the advances in the above four components and then provide promising strategies from the perspectives of four critical concerns, namely, electrode fabrication, anode protection, electrolyte formulation, and interface improvement in PSSLSBs. Ultimately, we propose rational design principles for each PSSLSB component, drawing on cutting-edge research achievements to guide the development of high-performance PSSLSBs.