Interpenetrated Bacteria-Carbon Nanotubes Film for Microbial Fuel Cells

Microbial fuel cells (MFCs) hold great potential for bioremediation and bioelectricity generation. To boost the power density of MFCs, tremendous efforts are devoted to improving the bioanode's design, mainly on increasing the bacteria-accessible electrode surface area. However, even for porous electrodes, it is difficult to fully utilize the interior surface for bacteria colonization. While making the pores larger improves the mass transport of bacteria, it limits the total surface area per unit mass or volume, and thus, the loading number of bacteria. Here, a bacteria-carbon nanotube (CNT) interpenetrated electrode structure is demonstrated that is capable of accommodating a large number of bacteria and offering a highly conductive network for charge transfer. The MFC device with the bacteria-CNT composite film as the anode achieves a remarkable power density of 34 W m(-3) (normalized to the volume of the anode chamber) and 12 102 W m(-3) (normalized to the volume of the anode). In addition to high power density, the unique composite structure allows CNTs to have immediate and maximal access to the bacteria embedded in the electrode, and thus, skipping the step of biofilm formation and reaching the maximum current immediately.