Ultrafine nano zirconia as electrochemical pseudocapacitor material

Ultrafine nano zirconia was prepared by a one-step sol–gel method and investigated by powder X-ray diffractions (PXRD) and transmission electron microscope (TEM). The results showed that its shape is spherical with the particle size from 2 to 3 nm. Electrochemical properties of nano zirconium oxide electrodes were measured by cyclic voltammetry, charge/discharge test and EIS in 6 M KOH electrolyte. The results obtained show that the ultrafine nano zirconia has a specific capacitance as high as 95 F g−1 at scan rate of 5 mV s−1. The capacitance is more than twice of the conventional zirconia, which was prepared from precipitation. In addition, the pseudocapacitor material exhibits excellent cycling performance, retaining 77% of the initial capacity after 500 cycles.