Porous Carbon Electrode from Starch Soluble for Realizing High‐Performance Supercapacitor

Organic potassium salts are the promising green activators for synthesizing porous carbon materials for energy storage. Herein, we report the synthesis of hierarchical porous carbon material derived from the mixture of soluble starch and ethylenediaminetetraacetic acid dipotassium salt dihydrate (EDTA‐2K) via carbonization and activation strategy. The sample is used as supercapacitors electrode, which exhibits superior mass specific capacitance (307.3 F g−1 at 1 A g−1), good rate performance (255.0 F g−1 at 10 A g−1), and excellent stability (retaining 83 % after 15000 cycles). This enhanced electrode performance is mainly due to the high specific surface area, the heteroatom co‐doping providing pseudo‐capacitance and the improved electronic conductivity. In addition, the asymmetric supercapacitor device shows a high energy density of 15 Wh kg−1 at the power density of 800 W kg−1 and capacitance retention of 90 % after 12000 cycles. N−O co‐doped porous carbon (NOPC) is prepared from soluble starch mixed with EDTA‐2K. The NOPCs performed as electrode in supercapacitor achieve mass specific capacitance (307.3 F g−1 at 1 A g−1), rate performance (255.0 F g−1 at 10 A g−1), and stability (retaining 83 % after 15000 cycles). The asymmetric supercapacitor device shows an energy density of 15 Wh kg−1 at the power density of 800 W kg−1 and capacitance retention of 90 % after 12000 cycles.