Ultrahigh Capacity of Monolayer Dumbbell C4N as a Promising Anode Material for Lithium-Ion Battery

2D carbon nitride materials play an important role in energy storage. Recently, 2D dumbbell (DB) C4N, a new member of 2D carbon nitride, is proposed and possesses two stable phases (DB C4N-I and DB C4N-II). In this paper, we use the first-principles calculations to examine the performance of monolayer (ML) DB C4N as anode for lithium-ion batteries (LIBs). After adsorbing Li-ions, the Fermi level of both two phases of ML DB C4N moves upward into the conduction band and shows an enhancement of the electrical conductivity. The maximum theoretical specific capacities for LIBs are up to 1942 and 2158 mAh g(-1) for I and II phase, respectively, which are about 4 similar to 5 times higher than that of the commercially used graphite (372 mAh g(-1)). The appropriate open-circuit voltages of similar to 0.60 and 0.68 V are also generated in ML DB C4N-I and II anodes, respectively. Finally, the diffusion barriers of Li ions are only 0.26 and 0.21 eV at I and II phase of ML DB C4N, respectively, providing appropriate rate capacities performance for LIBs. Therefore, we suggest that both two phases of ML DB C4N are promising anode materials for LIBs. (c) 2020 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.