Facile Synthesis of Porous Carbon Derived from Rice Husks with Enhanced Capacitance Performance

The porous carbons derived from biomass as electrode materials for supercapacitors have attracted widespread attention. Rice husks are abundant in Guangxi for rice is widely planted, and herein this paper presented the effects of the mass ratio of KOH/rice husks and activation temperature on the morphology, structure and electrochemical properties of the resultant carbons. The rice husks-derived porous carbon was produced by carbonization and KOH activation, and the porous carbon PAC-850-1:1 prepared at the activation temperature of 850 °C with the KOH/rice husks mass ratio of 1:1, displayed the high specific area of 2056.5 m2/g, much larger than the specific surface area of 17.9 m2/g for the carbon derived from direct pyrolysis without KOH activation. Such a high specific surface area improved the electrochemical performance of the obtained PAC-850-1:1 as the electrode material for supercapacitors, expressing the specific capacitance of 277.8 F/g at the current density of 0.5 A/g and good cyclic stability with remaining 82% at 10 A/g after 2000 cycles. The above capacitive performance, including the enhanced specific capacitance and good cycle stability, which benefited from the porous structure and good conductivity, as well as the simple fabrication strategy of the porous carbon obtained from low-cost rice husks, make it a potential candidate as electrode materials for supercapacitors.