The supercapacitive properties of Ni-Ru oxide composites

Abstract

NiO/RuO2 composite materials were prepared by chemical co-precipitation method, physical method and then heat-treatment. XRD spectra indicated that RuO2 particles were coated by NiO particles. Introduction of RuO2 into NiO electrodes improved the capacitive properties of electrodes and widened the range of work potential more than onefold. A maximum specific capacitance of 210 F · g-1 and specific energy of 14. 2 W · h · kg-1 were obtained for NiO-based composite electrodes with 10% RuO2 in 1 mol · L-1 KOH solution. By comparison of the chemical and physical introduction on the specific capacitance, the chemically modified composite electrodes had more stable properties. After 200 cycles, the specific capacitance of the chemical composite electrodes with 5% RuO2 kept 95% over the initial specific capacitance, but the physical composite electrodes were only 79%.