Solid-state batteries encounter challenges regarding the interface involving lithium metal

Lithium-ion batteries (LIBs) are highly significant in terms of electrochemical energy storage devices due to their remarkable attributes such as high energy density, long cycle life, and low cost. However, the utilization of liquid electrolytes in current commercial LIBs raises safety concerns. The primary challenge faced by current LIBs is to enhance energy density while ensuring safety. One promising solution is the utilization of solid-state lithium batteries, which involve a Li metal anode paired with solid electrolytes like organic polymer solid electrolyte (SE), sulfide-based SE, and oxide-based SE. These solid-state batteries have the potential to effectively address the aforementioned challenges. However, the development of such batteries has been hindered by complex interface issues between the SE and the lithium metal anode, unlike conventional liquid electrolytes. This review focuses on three main interface problems: interfacial reactions, lithium dendrites and interfacial physical contacts between SE and lithium metal anodes. It also presents corresponding solutions, aiming to provide valuable insights for the design and fabrication of higher energy density and safe solid-state batteries.