Effect of synthesis method on electrochemical activities of V2O5 nanoparticles for supercapacitor application
摘要
Vanadium pentoxide (V2O5) has attracted attention for supercapacitor applications due to its multifunctional properties. In this work, V2O5 nanoparticles were synthesized using hydrothermal, solution combustion and sol–gel methods. The structural and morphological analyses of the samples showed the effect of synthesis methods on the electrochemical and optical properties of the V2O5 electrode. The V2O5 synthesised through hydrothermal (V2O5-HT), solution combustion (V2O5-SC) and sol–gel (V2O5-SG) routes exhibited irregularly shaped nanosheets, agglomerated spherical-like particles and nanocube-like structure, respectively. The average crystallite sizes of the synthesized V2O5 nanoparticles were determined as 19.16, 18.77 and 20.48 nm for V2O5-HT, V2O5-SC and V2O5-SG, respectively. The optical bandgap energy of each sample was also calculated as 2.25, 2.3 and 1.9 eV for V2O5-HT, V2O5-SC and V2O5-SG, respectively. Cyclic voltammograms show the V2O5 electrodes’ pseudocapacitive properties in Na2SO4 electrolyte and faradic characteristics in KOH electrolyte. The impedance data can be fitted to a modified Randle equivalent circuit. The V2O5-HT, V2O5-SC and V2O5-SG electrodes respectively exhibit specific capacitances of 48.0, 16.3 and 49 F/g at 1 mV/s, and 93.1%, 100% and 108.4% of capacitance retention after 5000 cycles in 1 M Na2SO4 electrolyte. Our work provides a comparative study on V2O5-based electroactive materials synthesised using different methods. The results suggest that the V2O5 electrode needs integration with appropriate materials to be a potential electrode material for supercapacitor application.