Permanent Lithiophilic Layer for Anode‐Free Lithium‐Hydrogen Gas Battery

Abstract The necessity for high‐performance energy storage systems propels extensive research into diverse battery technologies. Among them, the lithium‐hydrogen gas (Li//H 2 ) battery, characterized by high energy density and low cost, is emerging as a promising candidate. Implementing a large areal capacity for the Li metal anode in an anode‐free Li//H 2 battery design is essential for achieving higher energy density and further reducing manufacturing costs. Here the study reports a permanent Li‐SiO x lithiophilic layer in‐situ generated on a Cu substrate during the Li//H 2 battery initial charge that facilitates homogeneous Li nucleation and drives the formation of a dense and thick Li deposition layer. The study manages to maintain the lithiation state to avoid the repetition of lithiation/de‐lithiation and significantly reduce the Li nucleation barrier. The anode‐free Cu@Li‐SiO x //H 2 battery with a high areal capacity of 5 mAh cm −2 exhibits promising cycling stability with a Coulombic efficiency of up to 99.1% under a current density of 1 mA cm −2 . Moreover, the significantly reduced Li nucleation barrier results in an increased round‐trip energy efficiency reaching up to 93.20%. This work proposes a novel strategy for constructing a lithiophilic layer to enhance the practical feasibility of large areal capacity anode‐free Li//H 2 batteries.