Integration of RuO₂/conductive fiber composites within carbonized micro-electrode array for supercapacitors

This study employed a carbon microelectromechanical system (C-MEMS) in fabricating a 3D micro-electrode array of conductive carbon cylinders directly on the surface of a graphite substrate. The capacitance of the array was further enhanced by decorating it with a composite material comprising highly-porous carbon nanofibers (CF) and electroactive RuO₂ nanoparticles to function as an active electrode. In galvanostatic charge-discharge tests, the specific capacitance of an electrode decorated with RuO₂ 30 wt%/CF was 219.2 F g⁻¹ at a current density of 0.5 A g⁻¹, which is 2.27 times higher than that of the pristine CF electrode. When the current density was increased from 0.5 A g⁻¹ to 3 A g⁻¹, the capacitance retention of the RuO₂ 30 wt%/CF electrode was 54.8%. A symmetric supercapacitor based on the RuO₂ 30 wt%/CF composite electrode exhibited an impressive energy density of 74.2 Wh kg⁻¹ with power density of 4333 W kg⁻¹. It also demonstrated good capacitance retention of 80.2% following 3000 consecutive charge/discharge cycles at a current density of 2 A g⁻¹.