One-step carbonization-activation synthesis of pomelo peel derived N, O-doped porous carbon for enhanced supercapacitve performance

Biomass-derived porous carbon has gained significant interest as ideal electrode material for supercapacitor owing to eco-sustainability, cost-effectiveness, and unique inherent microstructure. Herein, N, O co-doped porous carbons have been successfully obtained by single-step carbonization-activation method using waste pomelo peel as carbon source and KHCO 3 /CO(NH 2 ) 2 as activators. In the synthesis process, KHCO 3 as a pore-forming agent plays an important role, and CO(NH 2 ) 2 is used to assist the pore-forming process as well as N doping. Benefiting from high specific surface area (1378.5 m 2 ·g −1 ), predominant microporous structure and O, N co-doping, the best N, O co-doped porous carbon (denoted as PKNAC) exhibits high specific capacitance (364.5 F·g −1 , 1 A·g −1 ), favorable rate performance (retaining 63.86 %, 50 A·g −1 ) and good cycling durability (97.32 % retention, 20,000 cycles). Notably, the assembled quasi-flexible symmetrical supercapacitor in PVA/KOH gel electrolyte achieves the energy density of 13.7 Wh·kg −1 at a power density of 350 W·kg −1 . This work offers a convenient approach to prepare heteroatom-doped porous carbons from biomass waste for high-performance energy storage.