Honeycomb layered oxide Na3Ni2SbO6 for high performance pseudocapacitor

In this study, Na3Ni2SbO6 was synthesized by simple solid state method and its electrochemical behaviour was examined as a supercapacitor electrode for the first time. Na3Cu2SbO6 was also synthesized by the same preparation method in order to compare with the Na3Ni2SbO6. The structure and morphology of the samples were characterized by XRD, XPS and SEM analysis. The results shows O3-type honeycomb layered Na3Ni2SbO6 with microcrystal morphology. Electrochemical properties were characterized by cyclic voltammetry, galvanostatic charge/discharge measurements, and electrochemical impedance spectroscopy. The results showed that the specific capacitance of the Na3Ni2SbO6 and Na3Cu2SbO6 electrodes were 397 F/g and 50 F/g at the current density of 0.5 A/g respectively. The high pseudocapacitive nature of Na3Ni2SbO6 can be attributed to reversible redox reaction of Ni(II)/Ni(III).