Highly doped graphene with multi-dopants for high-capacity and ultrastable sodium-ion batteries

Heteroatom-doped graphene materials are one of the most promising electrode materials in energy-related realms. In this work, highly doped graphene nanosheets with tunable N and S codopants (NS-GNS) are prepared via a facile one-pot method and investigated in sodium-ion batteries (SIBs). During the pyrolysis, the starting materials can form planar sacrificial-templates that serve for the growth of 2D graphene structure and further in-situ convert into rich N and S dopant species, successfully solving the general challenge of high doping level of multi-heteroatoms into the graphene matrix. Integrating the abundant N, S and O-induced electrochemical redox centers at different potentials, the NS-GNS electrode demonstrates a high reversible capacity of around 400 mAh g(-1). Particularly, the ultra-long cycle life of 10,000 cycles and good rate capability of the present NS-GNS electrode make it promising for practical application in large-scale energy storage. This work guilds a direction toward redox-enhanced graphene materials with multi-dopants for energy storage and meanwhile provides a low-cost and scalable method for the mass production of well-defined graphene materials with tunable properties.