Biomass Porous Carbon Derived from Celery Leaves with High Capacitance for Supercapacitor

Abstract To develop environmentally friendly and high‐performance supercapacitors, the low‐cost, high‐capacitance renewable electrode material is at present viewed as one of the most challenging tasks for obtaining the next‐generation of energy storage devices. Therefore, in this study, Celery leaves, a common biomass vegetable, are used to prepare activated carbon for high voltage and high‐capacity supercapacitors through a simple method. Due to their high surface area and abundant nitrogen and sulfur heteroatoms, hierarchically porous carbon materials can simultaneously realize high capacity and long‐cycling durability. The specific capacitance has been recorded to be up to 753.0 F g −1 at 0.5 A g −1 with capacity retention as high as 96.7 % even after 5,000 cycles. Also, the assembled symmetric cell provided a high energy density of 17.36 Wh kg −1 at 250 W kg −1 . The effects of yellow and green colors and different activation temperatures on the properties of electrode materials were systematically studied. The results showed an excellent electrochemical performance in biomass carbon electrode materials, which would facilitate the development of a high‐quality energy system and a green supercapacitor.