Interfacial challenges and recent advances of solid-state lithium metal batteries

Growing market demands on portable electronics, electric vehicles, and energy storage system calls for the development of high-energy density lithium (Li) batteries. Li metal is considered as a promising anode material owing to their high capacity and low electrochemical potential. However, high reactivity of Li metal with conventional flammable liquid electrolytes easily forms Li dendrites, which may cause short-circuit and even catching fire, obstructing the wide application of Li metal batteries. Although non−/less-flammable solid electrolytes have replaced the conventional liquid electrolytes, solid-state Li metal batteries (SSLMBs) suffer from lower Li⁺ conductivities, chemical/electrochemical incompatibilities toward Li metal, and inhomogeneous Li⁺ flux at the interfaces. Therefore, many researchers have devoted themselves to solve these problems. For a better understanding on the current issues and recent advances, this article provides (1) a review on various solid electrolytes with high Li⁺ conductivity and their interfacial issues in SSLMBs, and (2) recent progress in stabilization of the interface between the Li node and solid electrolytes, including an electrolyte modification (e.g., composition, additives) and introduction of an interlayer.