A review of role of cathodes in the performance of microbial fuel cells

Cathodes play an essential role in evaluating the performance such as power density and especially the cost of microbial fuel cells (MFCs). Various types of cathodes such as air–cathode, aqueous air–cathode and bio-cathodes are used for MFCs in presence and absence of catalysts. The performance of these cathodes is differentiated in terms of their electrochemical performance, polarization and (or) power density. The material of cathodes significantly improves the power density as well as the electrochemical performance due to higher oxidation reduction reaction (ORR). The performance of cathodes can be improved by using an appropriate catalyst loading. This study reports the use of various cathodes such as air–cathode, aqueous air–cathode, and bio-cathode and their performance in terms of polarization and power density, and electrochemical performance (such as Linear Sweep Voltammetry (LSV), Cyclic Voltammetry (CV), and Electrochemical Impedance Spectroscopy (EIS)). Studies suggest that the air-cathodes provide better performance as compared to the other types of cathodes. Furthermore, the metal complexes such as Fe–N4 (catalyst) when embedded with other materials like activated carbon significantly improve the performance of the air–cathode.