Porous Carbon Polyhedrons with High-Level Nitrogen-Doping for High-Performance Sodium-Ion Battery Anodes

Sodium-ion batteries have been regarded as probable alternatives to lithium-ion batteries in the field of large-scale energy storage. In this work, nitrogen-doped porous carbon (NPC) polyhedrons are fabricated by using nitrogen-containing metalorganic frameworks as novel templates and precursors. The resultant NPC materials exhibit unique structure features, including porous structure, high-level nitrogen-doping and large surface areas. Among the NPC materials obtained at different annealing temperatures, NPC-600 exhibits the best sodium storage properties for sodium-ion batteries. The correlations between electrochemical properties and structure/composition of the NPC materials are disclosed. The best NPC-600 delivers a high reversible capacity of 231 mA h g(-1) at 0.05 A g(-1), superior rate capability with a stable capacity of 145 mA h g(-1) at 1 A g(-1), and good long-term cycling stability with a stable capacity of 182 mA h g(-1) after cycling at 0.5 A g(-1) for 500 cycles. The excellent sodium storage performances can be ascribed to the porous structure with enhanced reaction kinetics and high-level nitrogen-doping with high electrochemical reactivity.