Synthesis of Mn 3 O 4 /N-doped graphene hybrid and its improved electrochemical performance for lithium-ion batteries

Abstract Mn 3 O 4 /N-doped graphene (Mn 3 O 4 /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 Mn 3 O 4 nanoparticles are high-dispersely anchored onto the individual graphene nanosheets, and also found that, in contrast with pure Mn 3 O 4 obtained without graphene added, the introduction of graphene effectively restricts the growth of Mn 3 O 4 nanoparticles. Simultaneously, the anchored well-dispersed Mn 3 O 4 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 Mn 3 O 4 /NG electrode are highly improved during the electrochemical process. As the anode material for lithium ion batteries, the Mn 3 O 4 /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 g −1 after 10 cycles, indicating the superior capacity retention, which is better than those of bare Mn 3 O 4 , and most other Mn 3 O 4 /C hybrids in reported literatures. Finally, the superior performance can be ascribed to the uniformly distribution of ultrafine Mn 3 O 4 nanoparticles, successful nitrogen doping of graphene and favorable structures of the composites.