The Improvement of Power Output from Stacked Microbial Fuel Cells (MFCs)

Abstract

Three individual H-type two chambered microbial fuel cells were connected together using hexacyanoferrate (K₃Fe(CN)₆) as the catholyte. The stackable microbial fuel cells in series and parallel produced an open circuit voltage of 2.033 and 0.688 V, respectively. The open circuit voltages of individual microbial fuel cells were 0.689, 0.682, and 0.686 V, respectively. The maximum power density of a single cell was 136 mW/m², corresponding to the maximum current density of 350 mA/m² (normalized to the total surface area of anodic electrode, 10 cm²). The maximum power of 0.405 mW was obtained in serially connected stack (three microbial fuel cells), corresponding to the maximum current of 0.45 mA. The connection of three microbial fuel cell units in parallel produced the maximum power of 0.4 mW, corresponding to the maximum current of 1.25 mA. For a better understanding of the voltage reversal phenomenon, a dead cell (without substrate) was connected with the two other good working cells. It was found that voltage reversal occurred due to shortage of substrate in series connection.

Keywords:

• electricity generation
• microbial fuel cell
• mixed culture
• stack
• voltage reversal