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 BC2 =N-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 x 10(2) 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.