Evaluating the suitability of tungsten, titanium and stainless steel wires as current collectors in microbial fuel cells

The impact of bottom water light exposure on electrical and sediment remediation performance of sediment microbial fuel cells

Sediment microbial fuel cells (SMFCs) generate bioelectricity from benthic sediments and thus providing both bioelectricity generation and sediment remediation. However, the high internal resistance of the cathode leads to a low power output, which requires research on cathode treatment. In this study, we explored the influence of light irradiation on bioelectricity production and nutrient removal in the SMFC system. The microcosm experiment of the SMFC system was designed with artificial illumination of 500 lux (light-SMFC) and compared with dark conditions of 15 lux (dark-SMFC), which showed that the current increases during photoperiods. The study reveals that light-illuminated SMFC consistently produced the highest voltage, with the highest voltage (553 mV) being 1.3 times higher than the dark-SMFC (440 mV). The polarization curves show a significant reduction in internal cathodic resistance under light condition, resulting in increased voltage generation. The light-SMFC exhibits the highest maximum power density of 35.93 mW/m2, surpassing the dark SMFC of 31.13 mW/m2. It was found that light illumination in the SMFC system increases oxygen availability in the cathodic region, which supports the oxygen reduction reaction (ORR) process. At the same time, the high bioelectricity output contributes to the highest sediment remediation by greatly reducing the chemical oxygen demand (COD) and phosphate (PO4-P) concentrations. The study highlights the potential of light illumination in mitigating cathodic limitation to improve SMFC performance and nutrient removal.

Performance study of μDMFC with foamed metal cathode current collector

Micro Direct Methanol Fuel Cells (μDMFCs) often have application in moveable power due to their green and portable nature. In a μDMFC's structure, a current collector of the μDMFC needs to have high corrosion resistance such that the μDMFC can work for a long time in a redox reaction and respond to variable environmental conditions. To this end, four cathode current collectors were prepared. The materials selected were foam stainless steel (FSS) and foam titanium (FT), with fields of hole type and grid type. The performance of μDMFC with different cathode collector types was investigated by I–V–P polarization curves, Electrochemical Impedance Spectroscopy (EIS), and discharge test. The experimental results show that the maximum power density of the hole-type FSS cathode current collector μDMFC (HFSS-μDMFC) is 49.53 mW cm⁻² at 70 °C in the methanol solution of 1 mol L⁻¹, which is 70.15% higher than that of the hole-type FT cathode current collector μDMFC (HFT-μDMFC). The maximum power density of the grid-type FSS cathode current collector μDMFC (GFSS-μDMFC) is 22.60 mW cm⁻², which is 11.99% higher than that of the grid-type FT cathode current collector μDMFC (GFT-μDMFC). The performance of the HFSS-μDMFC is optimal in the methanol solution of 1 mol L⁻¹.

Micro Direct Methanol Fuel Cells (μDMFCs) often have application in moveable power due to their green and portable nature.

Biofouling effects on the performance of microbial fuel cells and recent advances in biotechnological and chemical strategies for mitigation

The occurrence of biofouling in MFC can cause severe problems such as hindering proton transfer and increasing the ohmic and charge transfer resistance of cathodes, which results in a rapid decline in performance of MFC. This is one of the main reasons why scaling-up of MFCs has not yet been successfully accomplished. The present review article is a wide-ranging attempt to provide insights to the biofouling mechanisms on surfaces of MFC, mainly on proton exchange membranes and cathodes, and their effects on performance of MFC based on theoretical and practical evidence. Various biofouling mitigation techniques for membranes are discussed, including preparation of antifouling composite membranes, modification of the physical and chemical properties of existing membranes, and coating with antifouling agents. For cathodes of MFC, use of Ag nanoparticles, Ag-based composite nanoparticles, and antifouling chemicals is outlined in considerable detail. Finally, prospective techniques for mitigation of biofouling are discussed, which have not been given much previous attention in the field of MFC research. This article will help to enhance understanding of the severity of biofouling issues in MFCs and provides up-to-date solutions. It will be beneficial for scientific communities for further strengthening MFC research and will also help in progressing this cutting-edge technology to scale-up, using the most efficient methods as described here.