Thin film oxide solid electrolytes towards high energy density batteries: progress of preparation methods and interface optimization

Abstract

All-solid-state lithium batteries have become a popular research topic due to their excellent potential in the realization of improved energy density and safety. Solid-state electrolytes are the key components of all-solid-state lithium batteries. Among them, oxide solid electrolytes (OSEs) have the advantages of wide electrochemical window, acceptable ionic conductivity, good thermal stability, and high mechanical strength. However, there are still some issues with thick OSE pellets and inadequate interface contact. In this review, we summarize the research progress in OSEs and introduce the preparation methods of thin OSE films, such as slurry casting, tape casting and solvent-free methods. Besides, the general strategies for improving interface contact and reducing interfacial impedance between OSEs and the cathode/anode are expounded, respectively. Finally, an outlook for the future development of OSEs toward industrial production and practical applications is provided.