Biomass nanoarchitectonics with activated rice husk char for nanoporous carbon as electrode material: Enhancing supercapacitor electrochemical performance

Nanoporous carbon from activated rice husk char was prepared via KOH activation at different ratios of rice husk: KOH, for using as electrode material in supercapacitor. The electrode could exhibit high performance in 6 M KOH aqueous electrolytes, particularly in terms of specific capacitance and power density. The BrunauerEmmett-Teller (BET) analysis showed a high specific surface area of 2833 m2/g with a mesoporous structure in a sample activated with a 1:3 ratio of rice husk to KOH. In this sample, a high specific capacitance of 195.36 F/ g was obtained at a current density of 1 A/g with excellent cycle stability of 99.87 % after continuous charge/ discharge test for 10,000 cycles at 10 A/g. Furthermore, the fabricated symmetric coin cell exhibits a power density of 526.88 W/kg and an energy density of 14.77 Wh/kg. The practical application of this cell is demonstrated by its ability to power a 3 V LED light bulb for over 900 s.