Optimizing Pre-Carbonization Temperature of Sesame Residue for Hierarchical Porous Carbon Materials in High-Performance Supercapacitor Applications.

This study examines the potential of utilizing sesame residue, a biological waste material, as a precursor for the intentional preparation of N, O co-doped porous carbon materials. The process involves a simple activation method using KNO3.The porosity and electrochemical properties of the resulting materials are tunable by varying the pre-carbonization temperature (0 °C, 300 °C and 600 °C). The pore structure and properties of synthetic materials vary depending on the pre-carbonization temperature. Our results indicate that at a pre-carbonization temperature of 300 °C a significant number of C-C and C-O bonds in the sesame residue are cleaved, resulting in a highly porous structure, appropriate specific surface area, and abundant heteroatom content. As a result, the SS-300 electrode displays exceptional capacitive performance (specific capacitance up to 312.7 F/g at 0.5 A/g) and outstanding cyclic stability (capacitance retention reaching 98.3% at 10 A/g after 8000 charge-discharge cycles). Moreover, the symmetric supercapacitor assembled using the SS-300 exhibits high energy densities in both 6 M KOH (4.58 Wh/kg) and 1 M Na2SO4 (15.6 Wh/kg), highlighting the potential of this material for energy storage applications.