N-Doped Carbon-Encapsulated Cobalt Nanoparticles on N-Doped Graphene Nanosheets as a High-Capacity Anode Material for Lithium-Ion Storage

A graphene-based anode material is demonstrated: N-doped carbon-encapsulated cobalt nanoparticles on N-doped graphene nanosheets (NC@Co@NG), in which cobalt nanoparticles encapsulated by N-doped carbon layer are highly dispersed on the N-doped graphene nanosheets, forming multiple sites for electrical conductivity enhancement and lithium insertion. When used as anode materials in lithium-ion batteries, the nanocomposites exhibit outstanding electrochemical performance, including a considerably large reversible capacity of 950.1 mAh·g -1 after 200 cycles at a current density of 100 mA·g -1 and Coulombic efficiency of 98%.