Influence of morphologies and pseudocapacitive contributions for charge storage in V2O5 micro/nano-structures

Three pure V2O5 micro/nano-structures including rods, hierarchical wires and porous tubes are synthesized via a chemical vapor deposition process by adjusting the oxidation temperature. Their surface-to-volume ratio increases significantly because of particle size decrease, pore quantity increase and hollow structure formation. Lithium-ion storage investigation in aqueous electrolyte indicates that the enlargement of surface area can suppress irreversible phase transition and lead to significant improvement of cycling stability, storage capacity and electrochemical kinetics. Furthermore, scan-rate dependence cyclic voltammetry analysis demonstrates that both pseudocapacitive and bulk Li+ storage are within these V2O5 electrodes and the relative contributions of them depend strongly on the scan rate. In porous V2O5 micro/nano-tubes, the surface pseudocapacitive storage dominates the total storage capacity at scan rates above 0.06 V s(-1), whereas the bulk Li+ storage is the domination effect for V2O5 micro/nano-rods at the scan rate ranging from 0.02 to 0.3 Vs(-1). At the special scan rate, the maximum and minimum capacity is observed in V2O5 porous micro/nano-tubes and micro/nano-rods, respectively. These studies should be useful for elucidating the morphological effects on Li-ion storage for V2O5-based electrodes. By varying key morphological parameters, the pseudocapacitive properties of V2O5 micro/nano-structure electrodes are expected to be affected. (c) 2013 Elsevier Ltd. All rights reserved.