Green pepper-derived hierarchical porous carbon for supercapacitors with high performance

Abstract

Renewable, low-cost and environmentally friendly porous carbon for high performance carbon electrode materials has attracted considerable attention in the energy conversion and storage fields. Herein, we have developed a sustainable route to fabricate porous carbon materials derived from green peppers through conventional thermal annealing and KOH-activation. The as-prepared GPAC-4 with a hierarchical porous structure exhibits a high specific surface area of 1052.70 m² g⁻¹ and a high capacitance of 863.1 F g⁻¹ at 1 A g⁻¹ as well as a good capacitance retention ratio of 97.80% at 10 A g⁻¹ over 10 000 cycles. Moreover, the assembled supercapacitor exhibits a capacitance of 214.45 F g⁻¹ at 1 A g⁻¹, which corresponds to a maximum energy of 42.89 W h kg⁻¹ at a power density of 1.2 kW kg⁻¹. Furthermore, the supercapacitor demonstrates good cycling stability with a low loss of 3.73% over 10 000 charge–discharge cycles. These findings could open up an exciting field for exploring reproducible vegetables as the raw materials for high performance supercapacitors.