Iron-assisted synthesis of nitrogen-doped carbon material for sodium-ion batteries

Edge functionalization of graphene planes with nitrogen improves the electrochemical performance of carbon anode materials in sodium-ion batteries. We propose a route for the synthesis of nitrogen-doped carbon materials with a nitrogen content of 6 at.%, half of which is pyridinic and pyrazole-like nitrogen. By simultaneous thermal decomposition of iron tartrate and acetonitrile vapor at 600 °C, nitrogen-doped carbon with embedded nanoparticles of iron carbides and iron nitride was synthesized. Heating this composite in air at a temperature of 250 °C followed by treatment with hydrochloric acid yields a highly porous carbon material. The oxidation and purification procedures do not affect the total nitrogen content, but result in the formation of pyrazole-like nitrogen at the edges of the graphitic layers. The developed material exhibits an improved capacity of 281–144 mAh g−1 at current densities of 0.05–1 A g−1 in sodium-ion battery.