CuCl2‐Modified Lithium Metal Anode via Dynamic Protection Mechanisms for Dendrite‐Free Long‐Life Charging/Discharge Processes

Abstract Lithium metal is considered as an ideal substitute to low‐capacity carbon anodes for rechargeable lithium‐ion batteries (LIBs) given its ultra‐high theoretical specific capacity of 3860 mAh g −1 and the lowest electrochemical potential. However, safety issues stem from the uncontrollable formation and growth of lithium dendrites, which severely plague the practical application of the Li anode. Here, a multi‐functional protection layer, prepared by a one‐step spin‐coating of CuCl 2 N ‐Methyl‐2‐Pyrrolidone (NMP) solution on a lithium metal surface is constructed. The as‐prepared protective layer has a variable porous morphology that consists of a conductive lithium‐copper alloy and electrochemically active CuCl, which proactively facilitates the homogeneous diffusion of Li‐ions, the elimination of random dendrite nuclei, and even distribution of charge at the Li anode surface, and subsequently the uniform deposition of Li + ions. Under such a dynamic protection mechanism, the proposed CuCl 2 modified Li electrode can stably cycle more than 1500 h at a current density of 1 mA cm −2 paired with lithium foil. Moreover, the assembled full battery achieves capacity retention of 85.6% even after 2000 cycles at a high rate of 5 C with a LiFePO 4 cathode. This as‐proposed dynamic protection mechanism via the incorporation of the electrochemically active component could provide new guidance in the preparation of the safe and high‐performance lithium metal anodes.