Effect of anode double-layered capacitance on performance of microbial fuel cell

The performance of a microbial fuel cell(MFC) is influenced by the anode biofilm with electrochemical activity, while the formation of anode biofilm greatly depends on the anode surface characteristics. To investigate how the two main characteristics of anode surface, surface area and double-layered capacitance, influence MFC performance, three kinds of activated carbon materials were used to make anodes with different double-layered capacitance values. The startup and operation performance of MFCs with those anodes were evaluated in the single-chamber air-cathode MFCs. When anode double-layered capacitance increased from 0.0012 F to 22.72 F, MFC starting up time decreased by 68% and maximal power density of MFC increased by 16.8 times to 546.1 m W·m-2. The images of scanning electron microscope(SEM) demonstrated that the biofilm formed on the anode with large capacitance was approximately one time thicker than that on the anode with small capacitance. Anode performance was directly influenced by anode double-layered capacitance other than anode surface area.