Minimum interspatial electrode spacing to optimize air-cathode microbial fuel cell operation with a membrane electrode assembly

Abstract

An optimum electrode spacing of less than 1cm was determined for an air cathode microbial fuel cell (MFC) with a membrane electrode assembly (MEA) system. The lag period decreased as the electrode spacing increased and the voltage generation increased. Stable power density increased from 93mW/m2 to 248mW/m2 when the electrode distance increased from 0mm to 9mm. In the polarization test, a maximum power density (400mW/m2) was obtained at a distance of 6mm. The oxygen mass transfer coefficient (KO=4.60×10−5cm/s) with a 0mm spacing was five times higher than that at a 9mm spacing (0.89×10−5cm/s). Long-term operation of the MFC exhibited relatively stable anode potentials of −285±25 (0mm) and −517±20mV (3, 6, and 9mm) and a gradual decrease in cathode potential for all distances, especially with 0-mm spacing. The performance of air cathode MFCs can be improved using minimum electrode spacing rather than no spacing.