Performance of PbO 2 on the basis of porous graphite/Pb conductive substrates for hybrid supercapacitors

Abstract

A lead dioxide electrode is obtained by anodic oxidation and applied to supercapacitors. Scanning electron microscopy (SEM) results show that the conductive substrates of graphite/Pb possess a three-dimensional porous structure after electrochemical expansion. Electrochemical results reveal that the prepared graphite/Pb conductive substrates (GPCSs) exhibit a high-specific capacitance and good electrical conductivity. To improve the performance of the electrode, a layer of active lead was deposited on the other surface of the GPCSs. Pb particles were dispersed evenly on the surface of the substrate from the SEM image. Finally, the hybrid supercapacitor was assembled with a PbO2 positive electrode and a lead negative electrode. At the beginning of the charge and discharge, the voltage was set to 2.4 V. During this process, the active Pb deposited on the surface of the substrate was oxidised to PbO2 gradually to form a PbO2/(graphite/Pb) hybrid capacitor. The specific capacity of the capacitor can reach 120.4 F/g. After a period of 3000 cycles, the capacity still reached up to 104 F/g, and the capacity retention rate increased up to 87%. These values indicate good cycling stability.