Synthesis, characterization and electrochemical assessment of hexagonal molybdenum trioxide (h-MoO3) micro-composites with graphite, graphene and graphene oxide for lithium ion batteries

Abstract

Hexagonal molybdenum trioxide (h-MoO3) microrods and their composites with graphite, graphene and graphene oxide (GO) are successfully synthesized by a soft chemistry route. The structural, compositional and electronic characteristics of the samples, investigated by a wide range of experimental techniques, evidence that the properties of the carbon material are preserved while yielding phase pure, highly crystalline oxide microstructures. h-MoO3 graphene and GO composites show excellent performance as Li ion batteries (LIBs) anodes. Precisely, h-MoO3 - GO electrodes deliver a remarkable specific capacity of 789 mA h g − 1 after 100 cycles at a high current density of 1000 mA g − 1, while h-MoO3 - graphene electrodes show an excellent stability at very high current densities, with specific capacities of 665 mA h g − 1 and 490 mA h g − 1 at 2000 and 3000 mA g − 1. The uniformly dispersed graphene and GO layers increase the structural stability of the composites and create a conductive network ensuring effective ambipolar diffusion of electrons and Li+ ions, as revealed by electrochemical impedance spectroscopy measurements and scanning electron microscopy of the cycled electrodes. These results expand the potential applications of h-MoO3 composites towards LIBs, paving the way for future improvements in this energy storage field.