Increasing Voltage and Current by Connecting MFCs in Series and Parallel

Five two-chamber mediator-less microbial fuel cells were connected in series and parallel forms of cell stacks.The performances of cell stacks were studied when MFCs were running in different stages and using different substrates and electron acceptors.The results showed that connection in series or parallel increased voltage and current,respectively.Using oxygen and hexacyanoferrate as the electron acceptors,the voltage of connection in series stack enabled the voltage up to 1.186 V at output power density of 18.83 mW/m2 and 1.417 V at 51.51 mW/m2,respectively,and output current of parallel stacked cells was 3 mA at output power density of 22.66 mW/m2,and 6.86 mA at 65.22 mW/m2.The difference of individual cells in stacks was the main reason to cause cell reversal,and the cell with larger internal resistance tended to be pole reversal at large working current.Reasonable hybrid connection of MFCs reduced the energy loss caused by the difference of MFCs in series stack,when external resistance was 30 Ω,the output power density of adopted hybrid connection stack(30.3 mW/m2) was around 4 times as that of series stacked MFCs(6.58 mW/m2).