University of Bayreuth researchers investigate microbial fuel cells

In Germany, at present, microbial fuel cells are mainly used in research laboratories to generate electricity. In order for industrial applications to be considered in the future, the fuel cells must be further developed so that they can produce consistently higher amounts of electricity than is currently the case. In a recent study published in the journal “Biotechnology for Biofuels and Bioproducts”, a research team from the University of Bayreuth has investigated factors playing a role in this. The choice of electrode material was shown to be particularly important for increasing stability and performance electrical circuit in microbial fuel cells is kept running by the metabolism of microorganisms: These feed on organic compounds, releasing electrons that are transferred to the fuel cell’s anode and from here to the cathode.

The Bayreuth research team tested two different electrode materials in its investigations into optimizing microbial fuel cells: Carbon felt and modified stainless steel mesh. The best results were achieved when the electrodes of the cells were made of stainless-steel mesh, the surface of which was modified with highly conductive carbon black and environmentally friendly polymer binder. The optimal distance between the anode and cathode was about four centimetres. This reliably generated quantities of electricity that can be used in practice, for example, to power environmental monitoring sensors in remote regions – without being connected to the power grid. Such fuel cells also make it possible to decontaminate petroleum hydrocarbon-contaminated soils while simultaneously producing electrical power. As the study shows, the efficiency of such detoxification strategies can be significantly increased if the suitable electrodes are available to capture the metabolic electrons.