Oxidative Synthesis of RuO[sub x]⋅nH[sub 2]O with Ideal Capacitive Characteristics for Supercapacitors

Abstract

A simple method with a high product yield (about 99%), i.e., chemical oxidation of RuCl3⋅xH2ORuCl3⋅xH2O with H2O2,H2O2, is successfully developed for the synthesis of hydrous ruthenium oxide (denoted as RuOx⋅nH2O).RuOx⋅nH2O). The main product of this chemical synthesis is RuO2⋅nH2ORuO2⋅nH2O with a significant amount of RuO3RuO3 from the X-ray photoelectron spectroscopy results. All RuOx⋅nH2ORuOx⋅nH2O powders without and with annealing in air between 150 and 400°C for 2 h show an amorphous structure from the X-ray diffraction and electron diffraction analysis. The annealed RuOx⋅nH2ORuOx⋅nH2O with the amorphous structure exhibits the ideal capacitive performance (i.e., highly electrochemical reversibility, high-power property, and excellent stability). The specific capacitance of annealed RuOx⋅nH2O,RuOx⋅nH2O, measured at 25 mV/s from a RuOx⋅nH2ORuOx⋅nH2O -coated graphite electrode (denoted as RuOx/G),RuOx/G), is ⩾500 F/g when the annealing temperature is between 200 and 350°C. © 2004 The Electrochemical Society. All rights reserved.