Improvement in electrochemical performance of V2O5 by Cu doping

Cu0.04V2O5 was prepared by a precipitation method followed by heat treatment at 300 and 600 °C. The material prepared at 300 °C showed porous morphology, whereas that prepared at 600 °C was highly crystalline. X-ray diffraction, Raman scattering and Fourier transform infrared spectroscopy showed both materials exhibiting the same structure as that of V2O5, with a slight lattice expansion. X-ray absorption spectroscopy confirmed the presence of V4+ cations in Cu0.04V2O5, which would increase the electronic conductivity of V2O5. Cu0.04V2O5 showed better electrochemical performance than V2O5 because of its high electronic conductivity and good structural stability. The material prepared at 600 °C delivered a reversible discharge capacity over 160 mAh g−1 after 60 cycles at a C rate of C/5.6. The material prepared at 300 °C showed good high-rate performance, which delivered a reversible capacity ~100 mAh g−1 when cycled at C/1.9. The discrepancy in the rate performance of Cu0.04V2O5 was attributed to the morphology of materials.