Ruthenium oxide thin film electrodes for supercapacitors

A ruthenium oxide thin film electrode with an average specific capacitance of 650 F/g and good high rate capability was prepared by electrostatic spra y deposition (ESD). This technique is a one-step process of preparing ruthe nium oxide thin film electrode compared with a multistep sol-gel process an d has features of low-temperature synthesis and easy control of surface mor phology. While as-prepared hydrous ruthenium oxide (RuO2 . xH(2)O) thin fil m was in an amorphous phase, the hydrous ruthenium oxide (RuO2 . xH(2)O) th in film became crystalline after annealing at temperatures > 200 degreesC. Ruthenium oxide thin film electrode annealed at 200 degreesC showed a cycli c voltammogram indicative of a typical capacitive behavior in 0.5 M H2SO4 e lectrolyte at a scan rate of 20 mV/s with the average specific capacitance of 650 F/g. The average specific capacitance was 640 F/g at 2 mV/s and 600 F/g at 50 mV/s, respectively, indicating that the average specific capacita nce decreases only slightly with increasing scan rate. (C) 2001 The Electro chemical Society. All rights reserved.