Research Advances in Interface Engineering of Solid‐State Lithium Batteries

ABSTRACT Solid‐state lithium batteries have attracted increasing attention due to their high ionic conductivity, potential high safety performance, and high energy density. However, their practical application is limited by a series of interface issues. In recent years, many efforts have been dedicated to solving these problems via interface engineering by providing feasible strategies for the optimization of lithiumion solid‐state battery interfaces. This paper reviews the recent developments of interface engineering in addressing interfacial issues. The existing interface problems are first systematically summarized, including poor contact, electrochemical instability, lithium dendrites, space‐charge layers, and element diffusion. Then, the corresponding interface characteristics and engineering strategies are thoroughly analyzed from the perspective of the cathode/electrolyte interface, the anode/electrolyte interface, and battery structure design. Finally, future research directions for the interface modification of solid‐state lithium batteries are discussed.