Effects of nano-SiO2 doped PbO2 as the positive electrode on the performance of lead-carbon hybrid capacitor

Abstract The PbO2 electrodes of lead-acid batteries are normally applied as the positive electrodes in lead-carbon hybrid capacitors. However, the effective utilization rate of active materials in the electrodes is only about 12.5 %, leading to a low energy density of lead-carbon hybrid capacitors. In this paper, a nano-SiO2 doped PbO2 electrode was prepared by the co-electrodeposition method. The energy density of the lead-carbon hybrid capacitor using a nano-SiO2/PbO2 electrode can reach 61 Wh kg-1 at 3 A g-1. The results show that the inert nano-SiO2 can establish electrolyte diffusion channels in the positive electrode, and thus improve the effective utilization rate of active materials. This work provides a new idea for the design and development of the positive materials for high-performance lead-carbon hybrid capacitors.