Electrodeposited PbO2 thin film as positive electrode in PbO2/AC hybrid capacitor

Abstract Lead dioxide (PbO 2 ) thin films were prepared on Ti/SnO 2 substrates by means of electrodeposition method. Galvanostatic technique was applied in PbO 2 film formation process, and the effect of deposition current on morphology and crystalline form of the PbO 2 thin films was studied by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The energy storage capacity of the prepared PbO 2 electrode was investigated by means of cyclic voltammetry (CV) and charge/discharge cycles, and a rough surface structure PbO 2 film was selected as positive electrode in the construction of PbO 2 /AC hybrid capacitor in a 1.28 g cm −3 H 2 SO 4 solution. The electrochemical performance was determined by charge/discharge tests and electrochemical impedance spectroscopy (EIS). The results showed that the PbO 2 /AC hybrid capacitor exhibited high capacitance, good cycling stability and long cycle life. In the voltage range of 1.8–0.8 V during discharge process, considering the weight of all components of the hybrid capacitor, including the two electrodes, current collectors, H 2 SO 4 electrolyte and separator, the specific energy and power of the device were 11.7 Wh kg −1 and 22 W kg −1 at 0.75 mA cm −2 , and 7.8 Wh kg −1 and 258 W kg −1 at 10 mA cm −2 discharge currents, respectively. The capacity retains 83% of its initial value after 3000 deep cycles at the 4 C rate of charge/discharge.