Enhanced performance of H-C3N2 monolayer as anode material for Li-ion batteries by phosphorus doping

Graphitic carbon nitride sheets (CxNy), x N y ), which possess a two-dimensional structure similar to N-doped graphene, have been extensively studied as potential anode materials for ion batteries due to their high nitrogen content and porous defect sites that can serve as atomic storage sites for alkali metals. compared with most carbon nitride sheets, monolayer H-C3N2 3 N 2 has the characteristics of higher pyridinic nitrogen content and porosity, and can provide more Li adsorption sites, resulting in a superior theoretical capacity of 2791 mAh/g. However, the high diffusion barrier of 1.75 eV implies the low charge/discharge rate, which limits its application in lithium-ion batteries. Here, this paper demonstrates that doping P atoms in H-C3N2 3 N 2 (PC18N11) 18 N 11 ) has some advantages for application in batteries. Specifically, monolayer PC 18 N 11 exhibits excellent stability and conductivity, much higher theoretical specific capacity (3542 mAh/g). Moreover, PC 18 N 11 exhibits metallic properties when Li-ion is adsorbed, the conductivity is improved, and the interaction between Li-ions will greatly reduce the diffusion barrier. These favorable properties indicate that P-doped H-C3N2 3 N 2 monolayer is a promising anode material for Li- ion batteries.