Construction of Robust and Criss‐Crossed LiOH Nanosheets on Lithium Metal Anodes for Stable Lithium–Sulfur Batteries

Abstract Metallic lithium (Li) is a promising anode for constructing high‐energy‐density Li metal batteries due to its low potential, high theoretical capacity, and low density. However, issues including high chemical reactivity, unstable solid electrolyte interface, and formation of Li dendrites impede its application. Herein, an interface layer of uniform, ultrathin, robust, criss‐crossed, and lithiophilic LiOH nanosheets is in situ constructed on Li metal anode by a bond water chemistry in C 2 H 8 N 2 ·H 2 O. Li deposition happens below the LiOH layer due to its ultralow electrical conductivity and abundant ion channels, which protects Li metal anode from corrosion by liquid electrolyte. The robust (14 GPa) and criss‐crossed LiOH nanosheets can physically suppress the growth of Li dendrites. The LiOH layer with lithiophilicity can homogenize Li + flux distribution and reduce Li + diffusion barrier on interface, promoting uniform Li deposition. Under the regulation of the multifunctional LiOH layer, issues of Li metal anode are relieved. When used in lithium–sulfur (Li–S) batteries, the C 2 H 8 N 2 ·H 2 O modified Li (MLi) can withstand the attack of soluble lithium polysulfides (LiPSs). Thus, the electrochemical performances of Li metal anodes and Li–S batteries are obviously improved. This study provides a new inspiration for the interface modification of Li metal anodes.