ZnCl₂-KOH modulation of biomass-derived porous carbon for supercapacitors

ABSTRACT

With the implementation of carbon neutrality, more and more researchers are devoted to the development of biomass-based porous carbon materials using agricultural and forestry wastes for energy storage applications. However, biomass-derived carbon materials are still suffering from structural instability and difficult to regulate the pore structure, so it is very essential to study the regulation of pore structure in activation process of biochar. Therefore, this work developed an approach to modulate the pore structure of biomass porous carbon. The pyrolyzed biochar was primary activated by ZnCl₂ to form the intermediate FC, and the FC was secondary activated by the impregnation method with the addition of trace KOH to form the graded porous carbon FCK-x. The prepared porous carbon exhibited a large specific surface area (2845 m²g⁻¹) and a large pore volume (1.43 cm³g⁻¹), which is very favorable for efficient ion transport in the three-electrode system, FCK-0.6 exhibited a specific capacitance of 321.7 F/g at 1A/g and the assembled supercapacitor exhibited high capacitance retention (95.17%) and charge retention (85%). This work provides a feasible way to modulate biomass pore structure.

Graphical abstract

KEYWORDS:

• Biomass waste
• pore structure
• porous carbon
• energy storage
• supercapacitors

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/15567036.2024.2303390

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [22373035], the Key Technologies Research and Development Program of Guangzhou [202206010122] and the CAS Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion [E229kf0201].

Notes on contributors

Changxing Lu

Changxing Lu was born in 1998 in Guangxi, China. He received his undergraduate degree from Guangxi University. Research focuses on the preparation of electrode materials for supercapacitors from biomass waste.

Zhaosheng Yu

Zhaosheng Yu received his Ph.D. in engineering from the School of Electric Power, South China University of Technology, and is currently an associate professor at South China University of Technology. His research areas are mainly in high value utilization of solid waste, power plant system optimization and economic dispatch, clean coal technology, and safety assessment of power battery. He has published more than 70 academic papers in journals.

Xikui Zhang

Xikui Zhang is from Guizhou, China. He has now received Master’s degree in engineering and is pursuing his Ph.D. at South China University of Technology, where his research focuses on the preparation of electrode materials for supercapacitors from biomass waste.

Xiaoqian Ma

Xiaoqian Ma received his Ph.D. in engineering from Huazhong University of Science and Technology, and is currently a professor at South China University of Technology. His research areas include combustion science, solid waste energy utilization, biomass energy utilization, power plant systems and energy conservation. he has published more than 300 academic papers in journals.