Correlation between porous structure and electrochemical properties of porous nanostructured vanadium pentoxide synthesized by novel spray pyrolysis

Porous nanostructured vanadium pentoxide (V₂O₅) particles were successfully prepared by spray pyrolysis (SP) in a precursor solution with an ammonium nitrate (NH₄NO₃) additive. The correlation between the porous structure and the electrochemical properties of the V₂O₅ particles was investigated. The porous structure markedly changed upon increasing the concentration of NH₄NO₃ in the precursor solution from 0 to 0.408 mol L^-1. Pore structure analysis based on N₂ adsorption-desorption isotherm measurements indicated that porous nanostructured V₂O₅ particles with a pore size of less than 100 nm can be prepared by the novel SP method and that an increase in the NH₄NO₃ concentration in the precursor solution can enlarge the pores in the V₂O₅ particles, especially those with a size between 20 and 80 nm. The porous nanostructured V₂O₅ prepared with an NH₄NO₃ concentration of 0.272 mol L^-1 exhibited a first discharge capacity of 400 mAh g^-1 at 20 mA g^-1. The unique porous structure of V₂O₅ particles significantly enhanced the rate performance and exhibited a first discharge capacity of 180 mAh g^-1 at 1200 mA g^-1, which is much higher than that of dense V₂O₅ particles (70 mAh g^-1).