Nitrogen-doped graphene nanosheets as anode materials for lithium ion batteries: a first-principles study

Abstract

First-principles calculations are performed to investigate the effects of the electron-deficiency of N-doped graphenes on their application in lithium ion batteries (LIBs), where three different defect models, graphitic, pyridinic, and pyrrolic graphenes are used. First, we investigate adsorption of a single Li atom on various graphenes and explore the change of the electronic properties in order to understand the adsorption mechanism. Then, adsorption of multiple Li atoms is also performed to consider the lithium storage properties of N-doped graphene nanosheets. The results show that the pyridinic graphene is the most suitable for Li storage with a high storage capacity, while the graphitic structure is the weakest of the three types. Moreover, the average potential of Li intercalation in the graphene materials was also calculated, and results indicate that the reversible capacity of the pyridinic structure can reach 1262 mAh g−1, which is higher than the experimental data (1043 mAh g−1). Therefore, we recommend pyridinic graphene in the N-doped structures as anode materials of lithium ion batteries and the corresponding reversible capacity of LIBs would be improved significantly. It is expected that this work could provide helpful information for the design and fabrication of anode materials of LIBs.