Battery Characteristics of Nanocrystalline V 2 O 5 and Conductive Polymer Composite Film Cathodes

Composite films of nanocrystalline V2O5 embedded in a conducting polymer, poly-3,4-ethylenedioxythiophene (PEDOT), were grown using an electrochemical polymerization method. The nanobeam-shaped V2O5 and PEDOT composite film cathodes have high capacities, excellent rate capabilities and cycling stabilities: the specific capacity was 269 mAhg-1 and the degradation rate was only 8% after 100 consecutive cycles at 1 C rate. The charge transfer resistances (Rct) for the nanobeam-V2O5/PEDOT composite film cathodes were smaller than that for the nanobeam-V2O5 powder cathode, in the electrochemical impedance measurements. The diffusion coefficient (DLi+) in the nanobeam-V2O5 crystallines was calculated to be approximately 4.6 x 10-8, and the values of DLi+ for each of α-, ε-, and δ-LixV2O5 crystalline phases, reversibly formed in the composite films during the discharging and charging processes, were able to be estimated in the range of (2.1~9.8) x 10-10.