Modulation of biomass‐based anode specific surface area and electrical conductivity on the enhancement of microbial fuel cell power generation capacity

Abstract BACKGROUND The design of efficient anode materials is critical for enhancing microbial fuel cell (MFC) performance, as electrode‐microorganism interactions largely determine the electron transfer efficiency. Biochar derived from natural biomass has been recognized as an excellent substitute for conventional MFC anodes. In this context, KOH‐activated biochar (BC‐KOH) and carbon nanotube‐loaded biochar (BC‐CNT) were synthesized from reed straw as MFC anodes, enabling a systematic evaluation of the respective contributions of specific surface area and electrical conductivity to the electrocatalytic performance of biomass‐based electrodes. RESULTS The BC‐KOH anode achieved the highest maximum power density (455.5 mW m −2 ) in MFC, surpassing the pristine biochar (223.42 mW m −2 ) and graphite felt (402.63 mW m −2 ) anodes by 104.86% and 13.13%, respectively. Attributable to its high specific surface area (1197.7 m 2 g −1 ), which provided abundant electroactive sites for microbial electron transfer and yielded an exceptional bilayer capacitance of 0.547 mF cm −2 . Meanwhile, the BC‐CNT anode exhibited a maximum power density of 332.12 mW m −2 (48.65% higher than pristine biochar), as its conductive nanotube network facilitated bacterial electron transfer and consequently reduced the charge transfer resistance to 47.97 Ω, compared to 96.12 Ω for the pristine biochar anode. CONCLUSION These findings demonstrate that biomass‐based anodes with tailored specific surface area or conductivity represent an economically viable and environmentally sustainable strategy for MFC applications, with a production cost at least 90% lower than that of conventional graphite felt. © 2025 Society of Chemical Industry (SCI).