KOH direct treatment of kombucha and in situ activation to prepare hierarchical porous carbon for high-performance supercapacitor electrodes

Kombucha, a renewable biomass, has been successfully utilized as an accessible carbon source to fabricate kombucha-derived hierarchical porous carbon (KHPC) by KOH direct treatment and in situ activation. The prepared KHPC shows an interconnected hierarchical porous structure, a pore volume of 0.41 cm(3) g(-1), and a specific surface area of 917 m(2) g(-1). Due to the multiple synergistic effects of these advantages, the KHPC-3 exhibits a high specific capacitance of 326 F g(-1) at a current density of 1 A g(-1) in 6 M KOH, good rate capability of 82% retention from 1 to 20 A g(-1), and cycling performance with 91.3% retention over 5000 cycles. Moreover, the KHPC-3 symmetric supercapacitor reveals a good energy density of 20.97 Wh kg(-1) at a power density of 871.2 W kg(-1) and retains 8.08 Wh kg(-1) at 6330 W kg(-1) in 1 M Na2SO4 electrolyte. Therefore, the KHPC obtained via the simple synthesis process shows great promise as an electrode material in energy storage devices.