Facile synthesis of nitrogen-doped graphene, and its advanced electrochemical activity toward efficient lithium ion storage

Abstract

Nitrogen-doped graphene (N-Graphene) has been extensively researched as the anode material for lithium-ion batteries, as the nitrogen doping provides massive active sites and improves the electrical conductivity and the ion diffusion kinetics, thus, significantly enhancing the lithium storage performance with reversible capacity and cycling stability. However, the high-rate performance and cyclability of the N-Graphene-based anodes are still to be achieved for fast-charging applications. Here, a new N-Graphene was successfully fabricated by annealing the commercial few-layer graphene with dicyandiamide. Along with the plenty of defects in the pristine graphene sheets, the doping of nitrogen effectively reduces the resistance and increases pore volume and the diffusion coefficient. Consequently, the N-Graphene anode exhibits outstanding lithium storage performance with superior high-rate performance and remarkable long-term capability (up to 10,000 cycles at 15 A g[Formula: see text] with a reversible capacity of 133 mAh g[Formula: see text]). Further kinetic analysis reveals that this excellent electrochemical behavior during the rapid discharge/charge operations can be attributed to the enhanced diffusion-controlled and surface capacitive storages. Our process may lead to an alternative way for producing competitive N-Graphene anode materials for efficient lithium ion storage.