Polyaniline nanofiber: an excellent anode material for microbial fuel cells

Sluggish electron transfer from the bacterial metabolic system to the electrode is a critical issue in microbial fuel cell (MFC) research. However, a number of strategies have already been demonstrated for the improved performance of MFCs through the chemical or electrochemical manipulation of the anode. In this study, a new anode fabrication technique was introduced with polyaniline nanofibers (PANInf) to increase the surface area of the anode in a three-dimensional pattern. A large number of bacteria were anchored to the high surface area anode through the electrostatic interaction between positively charged anode surface and negatively charged bacteria cell wall. An improved conductive nature also plays an important role in accelerating the electron transfer process, yielding a current density of 0.87 mA cm-2, which is almost a 73% increase from that of the PANI anode (0.503 mA cm-2). The maximum power density with a PANInf-modified anode was 1091 +/- 5% mW m-2, which is 40% higher than that of the PANI-modified anode (777 +/- 5% mW m-2). Impedance spectroscopic study shows that PANInf modification reasonably reduces the charge transfer resistance, leading to faster electron transfer kinetics.