First-principles study of BC7 monolayer an ultra-high capacity anode for lithium-ion and sodium-ion batteries applications

Abstract

In this work, via first-principles calculations, a 2D material BC7 is predicted to be a good candidate as a promising anode material for Lithium (LIB) and Sodium (NIB) ions batteries. Our study indicated that the adsorption of Li/Na-ion on different sites at the surface of BC7 monolayer keep its metallic character. Then BC7 monolayer exhibits negatives values of the adsorption-energy for the Li-ion. Subsequently, our calculate have demonstrated that unit-cell BC7 monolayer has impressively a higher maximum theoretical capacity 4240.09mAh/g for Li-ion, and 870.25mAh/g for Na-ion as compared to other materials. Low activation energy barrier, for Li-ion (0.15eV) and for Na-ion (0.078eV), active ion migration involves fast diffusion on BC7 monolayer surface, consequently suggests its high capability for the fast charge and discharge processes.Finally, we demonstrated that BC7 monolayer has a low average open-circuit voltage of 0.73V for Li. These results highlight suggest that BC7 monolayer can be a promising anode material for high-performance Lithium and Sodium ion batteries.