Nitrogen/Oxygen Enriched Hierarchical Porous Carbons Derived from Waste Peanut Shells Boosting Performance of Supercapacitors

Abstract

AbstractThe high specific surface area and the fine electrical conductivity are the vital impacts, but they are always a pair of mutually counterbalancing factors in carbon‐based supercapacitors. Herein, a facile strategy of the combined CoCl2 catalytic graphitization and ZnCl2 activation is applied to synthesize porous carbonaceous materials with enriched nitrogen and oxygen doping from a cheap and abundant biowaste of peanut shells. The as‐produced carbon materials possess high surface area (1745–2257 m2 g−1), naturally nitrogen/oxygen co‐doping, and hierarchical porous structure. These physicochemical properties jointly endow these materials excellent supercapacitive performances: a high gravimetric specific capacitance of 343 F g−1 at 0.5 A g−1 and enduring long‐cycle performance of 90.9% capacitance retention after 10 000 cycles at 10 A g−1 in a 3‐electrode system with 6 m KOH electrolyte as well as a superior energy density of 42 Wh kg−1 at the high power density of 375 W kg−1 in an organic electrolyte. This low‐cost and facile approach shall open a new avenue to produce carbon materials with both high surface area and superior graphitization from the plentiful biomass for the potential energy storage applications.