Ductile Inorganic Solid Electrolytes for All-Solid-State Lithium Batteries

Solid electrolytes, as the core of all-solid-state batteries (ASSBs), play a crucial role in determining the kinetics of ion transport and the interface compatibility with cathodes and anodes, which can be subdivided into catholytes, bulk electrolytes, and anolytes based on their functional characteristics. Among various inorganic solid electrolytes, ductile solid electrolytes, distinguished from rigid oxide electrolytes, exhibit excellent ion transport properties even under cold pressing, thus holding greater promise for industrialization. However, the challenge lies in finding a ductile solid electrolyte that can simultaneously serve as catholyte, bulk electrolyte, and anolyte. Fortunately, due to the immobility of solid electrolytes, combining multiple types of solid electrolytes allows for leveraging their respective advantages. In this review, we discuss five types of solid electrolytes, sulfides, halides, nitrides, antiperovskite-type, and complex hydrides, and the challenges and superiorities for these electrolytes are also addressed. The impact of pressure on ASSBs has been systematically discussed. Furthermore, the suitability of electrolytes as the catholyte, bulk electrolyte, and anolyte is discussed based on their functional characteristics and physicochemical properties. This discussion aims to deepen our understanding of solid electrolytes, enabling us to harness the advantages of various types of solid electrolytes and develop practical, high-performance ASSBs.