Response of current distribution in a liter-scale microbial fuel cell to variable operating conditions

Microbial fuel cells (MFCs) are an emerging technology in renewable energy and waste treatment and the scale-up is crucial for practical applications. Undoubtedly, the analysis and comprehension of MFC operation necessitate essential information regarding the response of the current distribution to variable operating conditions, which stands as one of its significant dynamic characteristics. In this study, the dynamic responses of current distribution to external stimuli (external load, temperature, pH, and electrolyte concentration) were investigated by employing a segmented anode current collector in a liter-scale MFC. The results demonstrated that, with respect to the anodic segment close to the cathode, a major response of the segment current to changes in load, temperature and pH was observed while minor response to changes in ion concentration. It was also found that external stimuli-induced high current usually led to a worse current distribution while increasing electrolyte ion concentration could simultaneously improve the maximal power generation and current distribution. In addition, the response time of segment current to input stimulus followed the pattern of temperature ˃ pH ˃ ion concentration ˃ external load. The results and implication of this study would be helpful in enhancing the operational stability of scale-up MFCs in future practical application.