Facile synthesis and electrochemical properties of RuO2 nanofibers with ionically conducting hydrous layer

The facile synthesis, by electrospinning of highly conductive RuO2 fiber mats as the conducting core of electrochemical capacitors, is reported. Electrospun RuO2 fiber mats, calcined at 400 degrees C, exhibited highly porous morphologies composed of crystalline RuO2 nano-particles with an average particle size of 10 nm. The highly conducting (sigma = 288 S cm(-1)) fiber mats were used as the basis of a hybrid electrochemical capacitor in which the fiber mats served as the conducting core for electrochemically deposited hydrate RuO2 center dot nH(2)O overlayers. These electrochemical capacitors exhibited superior characteristics: a high specific capacitance of similar to 886.9 F g(-1) (based on the mass of the hydrous RuO2 coating layer) at scan rate of 10 mV s(-1) and high rate capability with a capacity loss of only 30% from 10 to 2000 mV s(-1). This is attributed to the superior electron transport pathways provided by the fiber mat core to the upper ionically conducting hydrous RuO2 coating layer.