BC₂N/Graphene Heterostructure as a Promising Anode Material for Rechargeable Li-Ion Batteries by Density Functional Calculations

We performed density functional calculations to systematically investigate the adsorption and diffusion properties of Li atoms in three different structures of BC₂N and the heterostructures (I-BN and I-HH) formed by a combination of BC₂N-I and graphene as anode materials. The theoretical calculations predicted that monolayer BC₂N-I has a high capacity (546 mAh/g) with an average voltage of 0.32 eV. However, Li adsorptions on the BC₂N-II and BC₂N-III monolayers are not energetically favorable reactions. After combining with graphene, the capacity of the heterostructure I-BN has been greatly enhanced to 691 mAh/g and the lowest energy barrier of diffusion pathways is also obviously reduced to 0.073 eV. In theory, the fastest Li diffusion mobility in the interface of I-BN is about 6.6 × 10² times faster than that on a BC₂N-I sheet at room temperature. In this work, we made a comparison of monolayer BC₂N and the heterostructures of BC₂N/G, and suggest that I-BN is a promising anode material for lithium-ion batteries due to its high intercalation capacity and fast charge/discharge rates.