Improved performance of graphene doped with pyridinic N for Li-ion battery: a density functional theory model.

The performance of N-doped graphene on Li-ion battery has been investigated systematically by means of a density functional theory method. Pyridinic N doping, graphitic N atoms and 5-8-5 double vacancies have been selected as the functional defects to study their influence on Li storage compared to the pristine graphene. It has been confirmed that introducing pyridinic N atoms with p-type doping is a suitable method, especially for graphene doped with 4 pyridinic N atoms, whose structural distortion induced by Li intercalation is small and supplies strong force for Li adsorption. The diffusion barrier for this model is lower than for pristine graphene, both for the side and center diffusion routes, contributing to the high mobility. In addition, we point out that the strong catch force for Li will cause more Li to stay on the pyridinic N-doped graphene during the charge-discharge cycles, leading to a faster decrease of capacity compared to pristine graphene.