Effect of Pt nanostructures on the electrochemical properties of Co₃O₄ electrodes for micro-electrochemical capacitors

We report on the formation and electrochemical properties of Co₃O₄/Pt nanocomposite electrodes, which were fabricated by an RF magnetron co-sputtering system, for micro-electrochemical capacitors. High-resolution electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy examinations are performed to characterize the structural and chemical properties of the Co₃O₄/Pt nanocomposite electrodes. It is shown that the Co₃O₄/Pt6020 nanocomposite electrodes where RF powers of 60 and 20 W were applied to Co₃O₄ and Pt targets, respectively, give capacitance of 391.6 F/cm³ at 100 mV/s along with superb high-rate performance, which is much higher that those of Co₃O₄ only and other nanocomposite electrodes. The improvement is explained in terms of the formation of Co₃O₄-Pt combined nanostructures and their good electrical conductivity.