Valorization of lignin: Application of lignin-derived activated carbon in capacitors and investigation of its textural properties and electrochemical performance

• Published in: Diamond and related materials 2022-02, Vol.122, p.108791, Article 108791
• Main Authors: Wang, Liangcai, Feng, Xin, Li, Xiang, Ma, Huanhuan, Wu, Jielong, Chen, Yu, Zhou, Jianbin
• Format: Article
• Language: English
• Subjects: Activated carbon; Capacitance; Capacitors; Correlation coefficients; Electrochemical analysis; Lignin; Specific capacitance; Specific surface; Surface area; Textural properties; Thickness
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2021.108791

This work provides an idea for the efficient and harmless utilization of lignin and further evaluates the textural properties of lignin-derived activated carbon/specific capacitance relationship. The yield of apricot shell lignin (ASL) was 30.42%. H3PO4/KOH was used to assist the preparation of ASL-derived activated carbons (AACs) for capacitors. The AAC prepared at a ratio of H3PO4 weight to ASL weight of 3 (AAC-P-3) had a specific surface area of 1475.16 m2/g. Similarly, the AAC obtained at a ratio of KOH weight to ASL weight of 2 (AAC-K-2) owned a specific surface area of 2136.56 m2/g. At 0.50 A/g, the specific capacitance of AAC-P-3 and AAC-K-2 was 169.14 F/g and 236.00 F/g, respectively. The average value of the correlation coefficients (AR2) between specific surface area and specific capacitance was highest, i.e., 0.983, followed by the AR2 (0.978) between Vmicro/Vmeso and specific capacitance, the AR2 (0.975) between pore-wall thickness and specific capacitance. Consequently, when using a current density range of 0.50–10.00 A/g and a three-electrode configuration with a 6 M KOH electrolyte, the specific capacitance of AACs depends not only on the specific surface area but also on the Vmicro/Vmeso, pore-wall thickness, and Vmicro. [Display omitted] •AACs prepared by H3PO4 and KOH activation show distinctly different pore structures.•The specific capacitance of AACs was higher than the specific capacitance of commercially available supercapacitors.•Specific capacitance for AACs depends not only on the specific surface area but also on the Vmicro/Vmeso, pore-wall thickness, and Vmicro.