Biomass-based porous carbon for high-performance supercapacitor electrode materials prepared from Canada goldenrod

Preparing activated carbon from biomass materials that can be used as electrode materials for supercapacitors is crucial for realizing new green energy storage and conversion technologies to fulfill environmental requirements. Herein, activated carbon was prepared via high-temperature carbonization and KOH activation using Canada goldenrod as a raw material, which is a serious threat to the ecological environment. Using this activated carbon as the active material and 6 M KOH and 1 M TEABF4/AN as the electrolytes, aqueous and organic coin-cell symmetrical supercapacitors were prepared, respectively. The specific capacitance of activated carbon was calculated to reach 320 and 123 F/g at a current density of 0.1 A/g during its testing in a two-electrode system, corresponding to energy densities of 40 and 112.1 Wh/kg, respectively. The power density of the aqueous supercapacitor was 9 KW/Kg at 10 A/g, while that of the organic supercapacitor was 12.2 KW/Kg at 5 A/g; after 10,000 cycles of the charge–discharge test, the capacity retention rate reached 93.6 % and 86.4 %, indicating the excellent electrochemical performance of the prepared supercapacitor. In addition, the specific capacitance reached 366 and 252 F/g at capacitance densities of 0.1 and 0.5 A/g, respectively, during its testing in a three-electrode system. The results of this study indicate that Canada goldenrod is a good biomass-based precursor material for preparing porous carbon for supercapacitors.