This article focuses on understanding the relationship between structural characteristics such as specific surface area and random distribution of basal and edge graphite planes in nanoporous carbon materials and their capacitance when used in supercapacitor electrodes. Transmission electron microscopy images, Raman spectroscopy data, and electrochemical measurements for biomass-derived and commercially avalable materials are presented and discussed.

This study explores the correlation between the structural and electrochemical characteristics of biomass-derived nanoporous carbon materials for high-performance supercapacitors (SCs). The carbon materials are synthesized from plant residues, including wood, lignocellulose pyrolysis tar, or hemp stalks, by thermochemical activation in sodium hydroxide melt. Structural characterization using nitrogen absorption-desorption isotherms, Raman spectroscopy, and transmission electron microscopy reveals a predominance of slit-like micropores and high structural disorder. The electrochemical performance of these materials is measured in pouch SC prototypes and demonstrates high specific capacitance in the range of 135–176 F/g compared to 104–120 F/g for commercial coconut shell-derived carbon materials. Notably, the hemp-derived carbon demonstrates the highest volumetric capacitance of 93 F/cc compared to 71–72 F/cc for the widely used HayCarb or YP50F carbons. SC pilot prototypes with a rated capacitance of 250 F containing hemp-derived electrodes pass the standard IEC 62 391 life test at a nominal voltage of 2.85 V. These results confirm the promising potential of biomass-derived carbon as sustainable and efficient electrode materials for next-generation energy storage systems.