Mixed Proton-electron Conducting Nanocomposite Based on Hydrous RuO₂ and Polyaniline Derivatives for Supercapacitors

Abstract

Mixed proton-electron conducting nanocomposites have been formed based on a hydrous ruthenium oxide and a proton-conducting polymer for new supercapacitor energy storage nanomaterials with high capacitance and excellent rate capability. The nanocoating was carried out by polymerizing nano-ordered poly [3-(4-aminophenyl)propionic acid] (PAPPA) thin film on the surface of the hydrous ruthenium oxide nanoparticles under ultrasonic irradiation. From the transmission electron microscopy observation, PAPPA film was found to form compactly and thinly on aggregated hydrous ruthenium oxide particles with diameter of ca. 20 nm (primary size). At a low scan rate of 2 mV s⁻¹, the specific capacitance obtained for the nanocomposite electrode was 1210 F g⁻¹ which was higher than that for the ruthenium oxide nanoparticles itself (975 F g⁻¹). More importantly, the nanocomposite thin-film electrode maintained its high capacitance (ca. 1000 F g⁻¹) even at an ultrafast scan rate of 1000 mV s⁻¹.