Improved Performance of Mn3O4 Nanoparticles on Nitrogen-doped Graphene for Lithium Ion Battery Anodes

Abstract

Lithium ion batteries (LIBs) have been widely applied as major power sources for electronic devices. To utilize lithium ion battery to electric vehicles, plenty of research is going on. Developing new electrode materials with high specific capacity for excellent lithium ion storage properties is very desirable. In this research, a simple hydrothermal method for the growth of Mn3O4 nanoparticles onto nitrogen-doped graphene (N-doped graphene) for high-performance lithium ion battery (LIB) anodes is introduced. Hydrazine plays a fundamental role in the formation of such nanostructures as it can act both as a reducing agent and as a nitrogen source. In the synthesized composite, highly crystalline Mn3O4 nanoparticles with average sizes of 20–50 nm are homogeneously dispersed on both sides of the N-doped graphene. The nitrogen content in the doped graphene is confirmed by elemental analyzer, and 2 wt% of the sample is found to be composed of nitrogen element. The as-prepared Mn3O4/N-doped graphene composites exhibit remarkable electrochemical performance, including high reversible specific capacity, outstanding cycling stability, and excellent rate capability (approximately 400 mA h g-1 at 2.0 A g-1) when used as the anode material for LIBs. The improvement in the electrochemical properties of the material can be attributed to graphene, which acts as both an electron conductor and a volume buffer layer, and nitrogen doping allows for fast electron and ion transfer by decreasing the energy barrier. This type of metal oxide/N-doped graphene composites can be promising candidates for high-performance anode materials for LIBs.