Waste Xylose Mother Liquor Derived 3 D Graphene‐Like Porous Carbon with Ultrahigh Specific Capacitance and Energy Density for Supercapacitors

Abstract

In this paper, we developed a simple strategy for preparing three‐dimensional porous carbon from xylose mother liquor for high‐performance supercapacitors. Through simple regulation of activation temperature, the porous carbon prepared under optimized conditions have a perfect honeycombed structure with fewer layers and co‐existing macropores, mesopores and micropores. The product also has high content of self doped hetero‐atoms of O (10.2 at%) and N (0.5 at%). The constructed supercapacitors based on this porous carbon exhibited excellent performance with fantastic specific capacitance of 544 F/g at 0.5 A/g, excellent rate performance of 260 F/g at 20 A/g, as well as long cycle stability of 90.2% capacitance retention after 10000 cycles at 10 A/g in 6 M KOH in three‐electrode systems. Notably, symmetric supercapacitors exhibited energy density of 22.3 Wh kg−1 at a power density of 448 W kg−1 in the aqueous electrolyte Na2SO4, and a even higher specific energy density of 42.8 Wh kg−1 was achieved at a high power density of 749.8 W kg−1 in the organic electrolyte Et4NBF4.