Usage of Co-Solvent for Fabricating the Composite Cathode for Sulfide-Based All-Solid-State Lithium Batteries

In recent decades, lithium-ion batteries (LIBs) have been widely used in electric vehicles and large-scale energy storage systems. However, current LIBs using the flammable organic electrolytes have a safety issue. Therefore, all-solid-state lithium batteries (ASSLBs) with enhanced safety and high energy density are in the spotlight. Among many solid electrolytes, sulfide-based solid electrolytes with high ion conductivity and ductile property are the most promising. In order to develop the ASSLBs, the composite cathode with high mass loading is imperative, which can be fabricated by the wet process suitable for mass production. Polar solvents can disperse a binder with polar groups well, but it may cause severe dissolution of sulfide solid electrolytes in the composite cathode. Therefore, we tried to use co-solvent that can disperse a polymer binder well and prevent the dissolution of sulfide solid electrolyte. Cycling performance of ASSLBs employing the wet-type composite cathode was evaluated and will be reported.