Enhancing extracellular electron transfer efficiency and bioelectricity production by vapor polymerization Poly...

Electron transfer efficiency in electroactive biofilm is the limiting factor for bioelectricity output of bioelectrochemical system. Here, carbon felt (CF) is coated with manganese dioxide (MnO₂) which acts as electron mediator in electroactive biofilm. A wrapping layer of conducting Poly 3,4-ethylenedioxythiophene is developed to protect the MnO₂ and enhance electron transfer efficiency of MnO₂ mediator. The hybrid bioanode (PEDOT/MnO₂/CF bioanode) delivered the highest electron transfer efficiency (6.3 × 10^-9 mol cm^-2 s^-1/2) and the highest capacitance of 4.78 F, much higher than bare CF bioanode (1.50 ± 0.04 × 10^-9 mol cm^-2 s^-1/2 and 0.42 F). As a result, microbial fuel cells could produce a maximum power density of 1534 ± 13 mW m^-2, approximately 57.7% higher than that with the bare carbon felt anode (972 ± 21 mW m^-2). Possible mechanisms are proposed to help understanding the different function of the PEDOT and MnO₂ on the anodic layer. This study introduces an effective method for the fabrication of high performance anode.