Lithium metal batteries with all-solid/full-liquid configurations

Lithium metal batteries, featuring a Li metal anode, are gaining increasing attention as the most promising nextgeneration replacement for mature Li-ion batteries. The ever-increasing demand for high energy density has driven a surge in the development of Li metal batteries, including all-solid-state and full-liquid configurations. The unique battery structure, as well as the electrode and electrolyte material selections, endows the two Li metal batteries with different superiorities in energy density, rate performance, safety, and service lifetime, which make them suitable for a wide range of application scenarios ranging from portable- to large-scale energy storage. Nevertheless, there are several critical issues that seriously deteriorate battery performances, such as Li dendrite growth, parasitic chemical reactivity, and high operating temperature. Considerable efforts have been made to address these challenges in Li metal battery systems. This review aims to provide a comprehensive overview of the scientific progress in all-solid-state and full-liquid lithium metal batteries. We first discuss the fundamental understandings of the two systems and then review the recent technological innovations in electrode and electrolyte materials. Finally, a perspective on their possible research directions is presented, which helps facilitate the diversified development of Li metal batteries towards commercialization.