First-principles study on β-GeS monolayer as high performance electrode material for alkali metal ion batteries

Based on the density functional theory calculations, we have investigated the feasibility of two-dimensional β -GeS monolayer as high-performance anodes for alkali metal ion batteries. The results show that the electrical conductivity of β -GeS monolayer can be enhanced after adsorbing the alkali metal atoms owing to the semiconductor-to-metal transition. The low diffusion barriers of alkali metal atoms on the β -GeS surface indicate a rapid charge/discharge rate without metal clustering. Moreover, the low average open-circuit voltage (0.211 V) and a high theoretical capacity (1024 mAh⋅g −1 ) for Na suggest that the β -GeS monolayer is a promising anode material for Na-ion batteries with high performance.