Preparation and characterization of RuO2/polypyrrole electrodes for supercapacitors

•Up to now, it is first reported that RuO2/PPy composite electrode was prepared by thermal decomposition oxidation and electrodeposition.•Also this paper reveals the growth mechanism for PPy particles covering RuO2 films, which resulted in sharp increase for PPy particles size when the deposition time was over 20 min.•In addition, specific capacitances of 657, 553, 471 and 396 F g−1 were achieved by cyclic voltammetry (CV) measurement at the scan rate of 50 mV s−1 as deposition times were 10, 20, 25, 30 min, respectively.•Charge–discharge performance is stable.•The results have a certain theoretical and practical significance.

Polypyrrole (PPy) embedded RuO2 electrodes were prepared by the composite method. Precursor solution of RuO2 was coated on tantalum sheet and annealed at 260 °C for 2.5 h to develop a thin film. PPy particles were deposited on RuO2 films and dried at 80 °C for 12 h to form composite electrode. Microstructure and morphology of RuO2/PPy electrode were characterized using Fourier transform infrared spectrometer, X-ray diffraction and scanning electron microscopy, respectively. Our results confirmed that counter ions are incorporated into RuO2 matrix. Structure of the composite with amorphous phase was verified by X-ray diffraction. Analysis by scanning electron microscopy reveals that during grain growth of RuO2/PPy, PPy particle size sharply increases as deposition time is over 20 min. Electrochemical properties of RuO2/PPy electrode were calculated using cyclic voltammetry. As deposition times of PPy are 10, 20, 25 and 30 min, specific capacitances of composite electrodes reach 657, 553, 471 and 396 F g−1, respectively. Cyclic behaviors of RuO2/PPy composite electrodes are stable.