Carbon nano-fiber forest foundation for ruthenium oxide pseudo-electrochemical capacitors†
Ruthenium oxide was coated on directly grown carbon nano-fibers (CNF) on nickel foam current collectors at different coating temperatures. The extended surface area and the porous nature of the CNF forest along with the pseudo-capacitance nature of ruthenium oxide enhanced the performance of the electrodes. As the ruthenium oxide coating temperature played a vital role in the charge storage process, an ideal temperature for the oxide formation was determined to optimize the capacitance and stability. Using 6 M KOH as the electrolyte, these samples showed a high aerial capacitance of 822 ± 04 mF cm−2 at a current density of 20 mA cm−2 and retained 94% of its initial capacitance after 5000 charge–discharge cycles. The maximum energy and power density measured were 362 mW h m−2 and 957 kW m−2 respectively. Considering the facileness and the high-performance metrics, this process is easy to scale-up and the electrodes are promising for high-power supercapacitors.