Graphene–molybdenum oxynitride porous material with improved cyclic stability and rate capability for rechargeable lithium ion batteries

Abstract

A graphene–molybdenum oxynitride (GMON) hybrid porous material was prepared by a thermal decomposition method and investigated as an anode material in lithium ion batteries. In the thermal decomposition reaction, a chemically homogeneous complex formed by ammonium molybdate and hexamethylenetetramine was used as the precursor for the synthesis of molybdenum oxynitride (MON), and graphene oxide was thermally reduced into graphene. Meanwhile, the graphene sheets were nitrogen doped by the ammonia generated during the thermal reaction. The GMON hybrid porous materials were characterized by X-ray diffraction, scanning electron microscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, and thermal gravimetric analysis. Nitrogen sorption analysis showed that GMON possesses an enhanced porosity compared with the MON prepared in the same method. Owing to the improvement in the porosity and the conductivity, the GMON anode exhibited a reversible capacity of about 960 mA h g⁻¹ at a current density of 100 mA g⁻¹, furthermore, the rate performance and the cycling stability of the GMON anode were dramatically enhanced in comparison with thermal reduced graphene oxide and MON.