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//H₂) 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//H₂ 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//H₂ 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//H₂ 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//H₂ batteries.