Synthesis of Physically Activated Carbons from <i>Vitellaria paradoxa</i> Shells for Supercapacitor Electrode Applications
This study investigates the processing of shea nut shells (SNSs), an abundant agricultural waste, into porous activated carbon for supercapacitor electrodes through a two-stage thermal treatment involving pyrolysis and physical activation with CO<sub>2</sub> and steam. The aim was to dev...
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| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-07-01
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| Series: | Inorganics |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2304-6740/13/7/224 |
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| Summary: | This study investigates the processing of shea nut shells (SNSs), an abundant agricultural waste, into porous activated carbon for supercapacitor electrodes through a two-stage thermal treatment involving pyrolysis and physical activation with CO<sub>2</sub> and steam. The aim was to develop sustainable, high-performance electrode materials while addressing waste management. Carbonization followed by activation yielded 16.5% (CO<sub>2</sub>) and 11.3% (steam) activation yields, with total yields of 4.3% and 2.9%, respectively. CO<sub>2</sub> activation produced carbon (AC_CO<sub>2</sub>) with a specific surface area (S<sub>BET</sub>) of 1528 m<sup>2</sup> g<sup>−1</sup> and a total pore volume of 0.72 cm<sup>3</sup> g<sup>−1</sup>, a graphitization degree (I<sub>D</sub>/I<sub>G</sub> = 1.0), and low charge transfer resistance (9.05 Ω), delivering a specific capacitance of 47.5 F g<sup>−1</sup> at 0.5 A g<sup>−1</sup>, an energy density of 9.5 Wh kg<sup>−1</sup> at 299 W kg<sup>−1</sup>, and a fast discharge time of 2.10 s, ideal for power-intensive applications. Steam activation yielded carbon (AC_H<sub>2</sub>O) with a higher specific surface area (1842 m<sup>2</sup> g<sup>−1</sup>) and pore volume (1.57 cm<sup>3</sup> g<sup>−1</sup>), achieving a superior specific capacitance of 102.2 F g<sup>−1</sup> at 0.5 A g<sup>−1</sup> and a power density of 204 W kg<sup>−1</sup> at 9.2 Wh kg<sup>−1</sup>, suited for energy storage. AC_CO<sub>2</sub> also exhibited exceptional cyclic stability (90% retention after 10,000 cycles). These findings demonstrate SNS-derived activated carbon as a versatile, eco-friendly material, with CO<sub>2</sub> activation optimizing power delivery and steam activation enhancing energy capacity, offering tailored solutions for supercapacitor applications and sustainable waste utilization. |
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| ISSN: | 2304-6740 |