Theoretical studies of C3N3Li/graphene heterostructure as a promising anode material of lithium-ion battery

Abstract

The electrochemical properties of g-CN and g-CN/graphene heterostructure as anode materials for lithium-ion batteries were investigated by density functional calculations. It is shown that the Li adsorbed in the pore of g-CN has strong interactions with g-CN and a high diffusion energy barrier, leading to Li being trapped in the pores. After the pores of g-CN are fully adsorbed (C3N3Li), the migration energy barrier of Li ion on the surface of C3N3Li decreased to 0.56 eV. The calculated capacity (197 mAh/g) using C3N3Li as the host system is in agreement with experiment results. Similarly, the adsorption energy of Li in the pore of g-CN in the g-CN/graphene heterostructure is − 2.74 eV and the diffusion energy barrier (2.44 eV) for Li ion is still too high to migrate in the adjacent pores. Therefore, C3N3Li/graphene was used as the host anode system, and suitable adsorption energies (−0.81 eV), low migration energy barrier (0.43 eV), and a capacity of 694 mAh/g were obtained, which suggests that C3N3Li/graphene can be a promising anode material for Li-ion battery.