Low electrical potential anode modified with Fe/ferric oxide and its application in marine benthic microbial fuel cell with higher voltage and power output

Abstract

Low voltage and power output limit the widespread application of marine benthic microbial fuel cell (BMFCs). To increase the cell power, a Fe/Ferric oxide modified anode fabricating by electrolytic deposition is reported here. The novel anode has a lower surface contact angle and higher wettability, which favors the adhesion of bacteria. It is firstly demonstrated that the electrical potential of the modified anode is about −775mV, much lower than that of the plain graphite (about −450mV). Open circuit potential of BMFC with the modified anode is about 1050±50mV, while the potential for the plain cells is only 700±50mV. In comparison with the plain graphite, the modified anode presents a 393-fold exchange current density and a higher kinetic activity. The output power reaches 7.4×10−2mWcm−2, 17.4-fold higher than that of the plain graphite. A composite mechanism of both chemical and microbial enhancement of the modified anode is proposed to explain its excellent electrochemical performance. The modified anode has potential for high-power output cell and novel voltage-booster design to make the BMFC utilization feasibility.