Optimizing pre-carbonization temperature of sesame residue for hierarchical porous carbon materials in high-performance supercapacitor applications

In this paper, the sesame residue, a common biomass waste, was used as a precursor to synthesize N,O co-doped porous carbon materials via a simple pre-carbonization and KNO3 activation two-step strategy. The apparent morphology and supercapacitor performance of the obtained materials can be regulated by changing the pre-carbonization temperature (0 & DEG;C, 300 & DEG;C and 600 & DEG;C). The consequences demonstrate that a large number of C-C and C-O bonds in sesame residue undergo cleavage and form abundant pore structure at the pre-carbonization temperature of 300 & DEG;C. After KNO3 activation, the material has a moderate specific surface area (1073.4 m(2 )g(-1)) and affluent heteroatom content (N: 7.52 at%, O: 17.65 at%). As a result, the SS-300 electrode displays exceptional capacitive performance (specific capacitance up to 312.7 F g(-1) at 0.5 A g(-1)) and outstanding cyclic stability (capacitance retention reaching 98.3% at 10 A g(-1) after 8000 charge-discharge cycles). Moreover, the symmetric supercapacitor assembled by SS-300 exhibits high energy densities in both 6 M KOH (4.58 Wh kg(-1)) and 1 M Na2SO4 (15.60 Wh kg(-1)), highlighting the potential of this material for energy storage applications.

Automated summary

In this study, N,O co-doped porous carbon materials were synthesized from sesame residue using a two-step strategy involving pre-carbonization and KNO3 activation. The morphology and supercapacitor performance of the materials were influenced by the pre-carbonization temperature. The SS-300 electrode demonstrated excellent capacitive performance and cyclic stability, making it a promising material for energy storage applications.