Facile synthesis of graphene–molybdenum dioxide and its lithium storage properties

Abstract

Graphene–molybdenum dioxide composites in several ratios have been prepared through a facile synthesis method. Depending on the ratio, the as synthesized composites have either 2-dimensional graphene sheets with MoO₂ particles anchored to them or a clustered agglomerate morphology. The composites have been characterised using Raman spectroscopy, X-ray diffraction, and electron diffraction to confirm the monoclinic MoO₂ phase that is present. Lithium storage properties of the as-synthesised samples were tested in a coin-type half cell assembly to determine the relationship between the ratio and the electrochemical performance. The sample with highest amount of MoO₂ (78 wt%) displayed the most promising lithium storage properties, with stable cycling performance at 0.2 A g⁻¹ that shows negligible capacity loss over 50 cycles, retaining a capacity of 640 mA h g⁻¹. The rate capabilities were also tested, and show a capacity of 380 mA h g⁻¹ at 2.0 A g⁻¹, which is comparable to the theoretical capacity of graphite and previously reported work on similar materials.