Al-F co-doping towards enhanced electrolyte-electrodes interface properties for halide and sulfide solid electrolytes

All-solid-state Li batteries (ASSLBs) using solid electrolytes (SEs) have gained significant attention in recent years considering the safety issue and their high energy density. Despite these advantages, the commercialization of ASSLBs still faces challenges regarding the electrolyte/electrodes interfaces and growth of Li dendrites. Elemental doping is an effective and direct method to enhance the performance of SEs. Here, we report an Al-F co-doping strategy to improve the overall properties including ion conductivity, high voltage stability, and cathode and anode compatibility. Particularly, the Al-F co-doping enables the formation of a thin Li-Al alloy layer and fluoride interphases, thereby constructing a relatively stable interface and promoting uniform Li deposition. The similar merits of Al-F co-doping are also revealed in the Li-argyrodite series. ASSLBs assembled with these optimized electrolytes gain good electrochemical performance, demonstrating the universality of Al-F co-doping towards advanced SEs.