Facile preparation of self-supporting electrode through phenolic resin-based activated carbon sphere/SWCNT and its application in symmetric supercapacitor

Activated carbon (AC) is a material possessing an excellent specific surface area and significant potential for application in electronic double-layer supercapacitors, especially when it shows a spherical morphology. Among various types, phenolic resin-based AC exhibits optimal performance. AC derived from phenolic resin forms spheres through an emulsion method, with the particle size controlled by adjusting the ratio of phenolic resin/deionized water and the dispersant content. Further, a self-supporting electrode is fabricated by a scraping method using single-walled carbon nanotube (SWCNT) slurry and activated carbon spheres. Using this electrode, symmetric supercapacitors are assembled with aqueous KOH (SS-K) and organic electrolyte (SS-T), respectively. The SS-K performs a high specific capacitance of 201.9 F/g at a current density of 1 A/g, while the SS-T features a wide potential window of 2.3 V. Moreover, SS-K displays a high energy density of 15.77 Wh/kg at a power density of 750 W/kg, whereas SS-T achieves an excellent energy density of 20.9 Wh/kg at 1150 W/kg. This work presents an efficient method for preparing high-capacity AC spheres and assembling high-performance self-supporting electrodes, facilitating the development of AC based supercapacitor applications.