The Li1+x V3O8 material was successfully synthesized at 450°C in short sintering duration by microwave sol–gel route. X-ray diffraction suggests oxygen defects in the lattice. Based on Randles–Sevcik formula, cyclic voltammograms measurements were conducted to measure Li+ ion diffusion coefficient. The material exhibits high discharge capacity of 250mAg−1 at 0.2mA/cm2 after 30 cycles in the range of 2.0–4.0V. Alternating current impedance tests show that the growth of the charge transfer resistance at 0.4mA/cm2 is more rapid than that of at 0.2mA/cm2 as the galvanostatical charge–discharge continues.