Graphene-like carbon-nitrogen materials as anode materials for Li-ion and mg-ion batteries

Abstract Two-dimensional materials have been considered to be promising potential electrodes of metal-ion batteries. Here we explored the application of three graphene-like carbon-nitrogen structures as anode materials in lithium (Li)–ion and magnesium (Mg)-ion Batteries. We first studied the intrinsic characteristic of C 2 N, C 3 N, and g-C 3 N 4 , explored possible adsorption positions in each structure, studied the diffusion path, energy barrier, voltage profile, and theoretical capacity. Our results show that the theoretical capacities of C 2 N anode is 671.7 mAhg −1 for Li-ions and 588.4 mAhg −1 for Mg-ions, which makes it a promising anode material. C 3 N is not suitable as anode material. Because of the few absorptions sites, the capacity of g-C 3 N 4 sheet is only 199.5 mAhg −1 for Li-ions and 319.2 mAhg −1 for Mg-ions, which makes it unsuitable as anode material but its performance can be much improved when curled into nanotubes. Using Mg-ions instead of Li-ions can reduce the deformation of the material (for C 2 N) at the maximum concentration or improve the theoretical capacity (for C 3 N 4 ), lowing the maximum open circuit voltage while improving the diffusion energy barrier.