Effect of the Membrane Electrode Assemble Design on the Performance of Single Chamber Microbial Fuel Cells

摘要

Membrane electrode assemble (MEA) design is one of the crucial component of MFC. Therefore, the MEA design is critical to improving MFC's performance. In this work, effects of the presence of the cathode microporous layers and the distance between anode and cathode electrodes on MFC's performance are investigated. The experimental result indicates that the peak power density first decreases from 973 to 797 mW/m~2 when decreasing the distance from 2 to 1 cm, and then increases to 955 mW/m~2 when further reducing the distance to 0 cm. Meanwhile the ohmic resistance of the MFCs decreases from 34 to 14 and to 4.6 Ω, with the reduced distance. This is because that the peak power density is improved by increasing the anode potential and decreasing the ohmic loss due to the reduced distance. However, when distance reduced from 1 to 0 cm, the decrease of cathode potential becomes the predominant factor. It is also found that the aerobic heterotrophic microorganism growing on the surface of both the proton exchange membrane and the anode electrode lowers the coulomb efficiency by consuming the organic substance. In addition, the presence of aerobic bacteria is the possible factor that induces the non-linear correlation between the ohmic polarization and electrodes distance.