Twin-graphene as a Promising Anode Material for Na-Ion Rechargeable Batteries

In this work, using density functional theory, a twin-graphene-based anode material is investigated for the use in rechargeable ion batteries with sodium as the intercalating ion. The pristine twin-graphene structure yielded two best adsorption sites of its surface where the Na atoms are adsorbed in a layer-wise fashion. We report a theoretical capacitance of 496.2 mAh/g for Na-adsorbed twin-graphene, which is significantly higher than those of many other carbon allotropies. From NEB calculations, a low diffusion barrier in twin-graphene suggests good diffusivity, and with a moderate value of open-circuit voltage, twin-graphene is a good choice for applications as an anode material in Na-ion rechargeable batteries.