Hybrid electrochemical capacitor of IrO₂ nanocrystal and hydrous RuO₂

Hybrid electrochemical capacitors of anhydrous IrO₂ nanocrystal and hydrous RuO₂ have been prepared via metal organic chemical vapor deposition (MOCVD) and electrochemical deposition. The structures were studied using scanning electron microscope (SEM), high resolution transmission electron microscope (HRTEM) and X-Ray Diffraction (XRD). The electrochemical properties were measured by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). In a miniaturized configuration, the CVD grown structure provides a connecting backbone of electron paths and open channels for ion migration to facilitate the charge delivery or acceptance from the electrodeposited hydrous RuO₂ of high pseudocapacitance. The sample of thermally reduced nanocrystals encased in RuO₂·0.46H₂O exhibits a total capacitance of ~484.75 Fg^-1 at 10 mVs^-1, higher than that of the RuO₂ 0.46H₂O coated as-grown nanocrystals of ~352 Fg^-1.