Activated Carbon Derived from the Agricultural Waste Camellia Seed Shell for High-Performance Supercapacitors

Under the background of the current promotion of global green, environmental protection, and energy conservation, the sustainable conversion of low-cost agricultural waste biomass into high value-added products has become a hot topic. Herein, agricultural waste camellia seed shells obtained after pressing oil are used to prepare porous carbon materials with a high specific surface area (SSA) and excellent electrochemical properties for the application of supercapacitors. The effects of different chemical activators and mass ratios on the pore structure and electrochemical properties of agricultural waste camellia seed shell-derived activated carbon (CSSC) were investigated. It has been found that the CSSC activated by KOH presents excellent physical and electrochemical performances, and the pore structures of all the prepared activated carbons were predominantly a combination of mesopores and micropores. Especially, owing to the high SSA (1219 m2 g–1) and porous structure of the CSSC–KOH-1:3 material, the electrode provides an outstanding specific capacitance of 305 F g–1 at a current density of 0.5 A g–1. Furthermore, the symmetric supercapacitor assembled with CSSC–KOH-1:3 electrodes can deliver a high energy density (15.37 W h kg–1) and power density (12.9 kW kg–1), and it can still maintain high cycling stability even after 10,000 charge and discharge processes. Therefore, this work provides a significant exploration for the high-value application of the agricultural waste camellia seed shell and low-cost preparation of the porous carbon for the application of high-performance supercapacitors.