Hierarchical Fe3O4@NC composites: ultra-long cycle life anode materials for lithium ion batteries

The composites of N-doped carbon-coated Fe3O4 nanoclusters (Fe3O4@NC) were prepared by a facile preparation process. The microwave-assisted solvothermal method was first employed to obtain Fe3O4 nanoclusters, and then using dopamine as carbon sources, the N-doped carbon-coated Fe3O4 nanoclusters were obtained by calcining in vacuum. By changing the amount of dopamine and calcination temperature, a series of products with different carbon-coating thickness and crystallinity were obtained. The composite synthesized by adding 0.08 g dopamine hydrochloride and calcining at 500 °C exhibits ultra-long cycle life and good rate capability, its reversible capacity can retain at 445 mAh g−1 after 2000 cycles even at a current density of 2 A g−1. The results indicate that the hierarchical Fe3O4@NC composites are promising high-performance anode materials for lithium ion batteries.