Performance evaluation and impedance spectroscopy of carbon-felt and reinforced stainless-steel mesh electrodes in terrestrial microbial fuel cells for biopower generation

Abstract

Terrestrial Microbial Fuel Cells (TMFCs) offer promising potential for renewable energy by harnessing microbial metabolism to generate electricity from soil-based organic matter. Electrode materials are key to TMFC performance, facilitating electron transfer between microbes and the circuit. However, the effect of electrode impedance on TMFC efficiency is not well understood. This study fills that gap by comparing surface-modified stainless-steel mesh (SMS) and carbon felt (CF) electrodes, focusing on performance metrics and impedance spectroscopy to optimize electrode design for improved power generation from TMFCs. The SMS electrode fabricated using the pasting and reinforcement process demonstrated superior performance with a maximum power of 859 μW compared to the 234 μW power of the CF electrode. This better performance of the SMS electrode was attributed to its pseudocapacitive behavior, enhancing internal charge storage capacity and overall MFC efficiency. Electrochemical impedance spectroscopy revealed a substantially higher charge transfer resistance in the CF electrode, resulting in a 190.8 % difference between the two electrodes. Conversely, the SMS electrode exhibited lower resistance and improved diffusion characteristics, facilitating efficient electron transfer and mass transport. These findings underscore the significance of tailored electrode materials in optimizing MFC performance and emphasize the utility of electrochemical impedance spectroscopy in elucidating complex electrochemical processes within MFC systems, thus guiding future advancements in sustainable power production in terrestrial MFCs.