Vanadium oxyhydroxide-modified reduced graphene oxide composite as cathode material for lithium-ion battery

Vanadium oxides and their derivatives are known for their performance in lithium-ion batteries (LIBs). However, the practical application of these materials in commercial LIBs is still hindered by their intrinsic low ionic diffusion coefficient and moderate electrical conductivity. To improve their conductivity and their structural stability, a robust scenario is proposed in this study, through the synthesis of the nanocomposite materials LixH2V3O8/reduced graphene oxide (rGO) as novel composite cathode materials for LIBs. The structure, composition, and morphology of the hydrothermal powders are characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). To evaluate the electrochemical performance of LixH2V3O8/rGO, cyclic voltammetry (CV), charge/discharge, and impedance spectroscopy studies were performed. The H2V3O8/rGO cathode exhibits improved electrochemical performance in terms of specific capacitance, reversibility, and stability compared to single-component LixH2V3O8. At 0.1 A g(-1), the specific discharge capacity for the pure LixH2V3O8 and the LixH2V3O8/rGO composite is about 320 mAh g(-1) and 3950 mAh g(-1), respectively. The improvement in the electrochemical capacity of the composite cathode is mainly ascribed to a cooperative effect between the reduced graphene, with good electrical conductivity, and the unique nano-sized H2V3O8.