Optimizing Current Collector Interfaces for Efficient "Anode-Free" Lithium Metal Batteries

Current lithium (Li)-metal anodes are not sustainable for the mass production of future energy storage devices because they are inherently unsafe, expensive, and environmentally unfriendly. The anode-free concept, in which a current collector (CC) is directly used as the host to plate Li-metal, by using only the Li content coming from the positive electrode, could unlock the development of highly energy-dense and low-cost rechargeable batteries. Unfortunately, dead Li-metal forms during cycling, leading to a progressive and fast capacity loss. Therefore, the optimization of the CC/electrolyte interface and modifications of CC designs are key to producing highly efficient anode-free batteries with liquid and solid-state electrolytes. Lithiophilicity and electronic conductivity must be tuned to optimize the plating process of Li-metal. This review summarizes the recent progress and key findings in the CC design (e.g. 3D structures) and its interaction with electrolytes.Anode-free Li-metal batteries (AFLMBs) are a promising candidate for future high-energy density batteries, however, besides many advantages (safety and low cost), they still face challenges in terms of poor cycling life. This work discusses the challenges, current status, and important discoveries in optimizing the current collector as the host for Li-metal plating, since its critical role for achieving superior electrochemical performance.