Synthesis of Mn3O4/N-doped graphene hybrid and its improved electrochemical performance for lithium-ion batteries

Mn3O4/N-doped graphene (Mn3O4/NG) hybrids were synthesized by a simple one-pot hydrothermal process. The scanning electron microscopy (SEM), transition electron microscopy (TEM), X-ray powder diffraction (XRD), Thermogravimetric analysis (TG), Raman Spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to characterize the microstructure, crystallinity and compositions. It is demonstrated that Mn3O4 nanoparticles are high-dispersely anchored onto the individual graphene nanosheets, and also found that, in contrast with pure Mn3O4 obtained without graphene added, the introduction of graphene effectively restricts the growth of Mn3O4 nanoparticles. Simultaneously, the anchored well-dispersed Mn3O4 nanoparticles also play a role as spacers in preventing the restacking of graphene sheets and producing abundant nanoscale porous channels. Hence, it is well anticipated that the accessibility and reactivity of electrolyte molecules with Mn3O4/ NG electrode are highly improved during the electrochemical process. As the anode material for lithium ion batteries, the Mn3O4/NG hybrid electrode displays an outstanding reversible capacity of 1208.4 mAh g(-1) after 150 cycles at a current density of 88 mA g(-1), even still retained 284 mAh g(-1) at a high current density of 4400 mA CI- after 10 cycles, indicating the superior capacity retention, which is better than those of bare Mn3O4, and most other Mn3O4/C hybrids in reported literatures. Finally, the superior performance can be ascribed to the uniformly distribution of ultrafine Mn3O4 nanoparticles, successful nitrogen doping of graphene and favorable structures of the composites.