Hierarchical porous carbons derived from leftover rice for high performance supercapacitors

Biomass-derived porous carbons have been extensively investigated as potential electrode materials of electrochemical energy storage devices. Herein, hierarchical porous carbons with high specific surface area and large mesoporosity are successfully prepared from leftover rice, a common meal surplus, benefiting from its unique swelled structure and the activation effect of potassium hydroxide. The hierarchical porous carbons exhibit outstanding electrochemical energy storage performances in 1 M TEABF(4)/PC (propylene carbonate) electrolyte, including a high specific capacitance of 153.2 Fg(-1) at 0.2 A g(-1) based on the active material, a high specific energy density of 22.6 Wh kg(-1) at a power density of 21,503 W kg(-1) based on the cells and over 87% capacitance retentions after 10,000 cycles at 1 A g(-1). Such excellent electrochemical performances demonstrate that leftover rice can be potentially applied as bioresource for high property porous carbon electrode materials of supercapacitors. (C) 2019 Elsevier B.V. All rights reserved.