Supercapacitive performance of hydrous ruthenium oxide (RuO2·nH2O) thin films deposited by SILAR method

The amorphous hydrous ruthenium oxide (RuO2·nH2O) thin films were deposited by a simple and inexpensive successive ionic layer adsorption and reaction (SILAR) method. These films were characterized for their structural, surface morphological, and compositional study by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDAX) techniques. The wettability test was carried out by measuring the water contact angle. The scanning electron microscopy study showed small RuO2 particles are grouped together to form porous agglomerates. The FT-IR study confirmed the formation of hydrous ruthenium oxide films. The hydrophilic nature of ruthenium oxide (RuO2·nH2O) thin films was observed from water contact angle measurement. The presence of Ru and O in the film was confirmed by EDAX analysis. The supercapacitor behavior of these films studied in 0.5 M H2SO4 electrolyte showed maximum specific capacitance of 162 F g−1 at 10 mV s−1 scan rate. These films exhibit 80% cycling performance after 2,000 cycles. The charge–discharge studies carried at 1 mA cm−2 current density revealed the specific power of 3.5 KW kg−1 and specific energy of 29.7 W Kg−1 with 93% coulombic efficiency.