Capacitive Ferrosoferric Oxide as an Anode to Enhance the Electrical Energy Output and Storage of Microbial Fuel Cells

Microbial fuel cells (MFCs) are electrochemical electricity generation devices that use microorganisms to degrade organic matter to produce electrical energy. The anode of microbial fuel cells (MFCs) is the carrier to which electrogenic microorganisms attach. However, traditional anodes do not have a storage function, which limits the application scope of microbial fuel cells. Effectively storing and utilizing the energy generated by MFCs is an important focus of ongoing research and is also key to realizing their effective application. A carbon felt film (CF) was used as the substrate, and a carbon felt film/ferrosoferric oxide (CF/Fe3O4) electrode was prepared by a hydrothermal method. In the power density test, the MFC system constructed with the CF/Fe3O4 electrode as a capacitive biological anode had a maximum power density of 5.09 W/m3, which was 4.43 times higher than that of the blank carbon felt film anode. In the charge–discharge test, the stored charge (Qs) released by the CF/Fe3O4 electrode was 157.12 C/m2 higher than that of the CF electrode after 45 min of charging–discharging. The modified ferrosoferric oxide anode was used in a microbial fuel cell to provide a scientific basis to construct microbial electrochemical systems with high power and energy storage functions.