Oxygen‐Enriched Porous Carbon Derived from Biomass Waste for Supercapacitors with High Electrochemical Performances

The porous carbon‐derived biomass is inexpensive and ecofriendly, making them the promising electrode materials for supercapacitors. In this work, oxygen‐enriched porous carbon is derived from Platanus fibers via a carbonization and activation process using KMnO 4 as the activator. KMnO 4 plays the role of both activator and modifier. The obtained porous carbon possesses high oxygen content and shows tube‐like hollow structures. The sample OPF‐700‐3 exhibits a high oxygen content (13.79%), total pore volume (0.64 cm 3 g −1 ), and specific surface area (1406 m 2 g −1 ). The prepared OPF‐700‐3 electrode material presents a high specific capacitance (318 F g −1 at 0.5 A g −1 ) and retains 181 F g −1 even at 50 A g −1 in a three‐electrode system. The as‐prepared symmetric supercapacitors have a high specific capacitance (252 F g −1 ) and an excellent cycle stability (96.5% specific capacitance retention after 20 000 cycles). Furthermore, it has a high energy of 7.04 Wh kg −1 at a power density of 22.66 W kg −1 . This study provides a facile, inexpensive, and environmentally friendly method for biomass prepared from porous carbon, which are used as electrode materials present excellent electrochemical performances.