UV Light-assisted Electropolymerization of Pyrrole on TiO2 for Supercapacitors: Investigating the Role of TiO2

Abstract

One-dimensional (1D) TiO2 nanorod array (TiNA) is used as the support for controllablly growing polypyrrole (PPy) on fluorine-doped tin oxide glasses as the electroactive material for supercapacitors (SCs). Ultraviolet (UV) light is applied during pyrrole electropolymerization on TiNA to provide photoholes for oxidation and improve charge-transfer between pyrrole and TiO2. The light condition and pyrrole monomer concentration for the electropolymerization play important roles on the deposition extent and the performance of the SC electrode. The specific capacitance (CF) value of 200.45F/g was obtained for the PPy/TiNA-based SC electrode at a scan rate of 5mV/s. The role of TiO2 is found to be significant in the electrode as the underlayer for the effective 1D electron transfer other than being the electroactive material for Faradic reactions. The CF retention of 72% is attained after 1,500 repeated charge/discharge processes at 2A/g for the optimized PPy/TiNA-based SC electrode. The result provides new sight to use poor electrocapacitive material as the highway for electron transfer to enhance the SC electrochemical performance and verifies the position to place the nanomaterial in the electrode is of great importance to affect the SC performance.