Bifunctional polypyrrole/ferroferric oxide as anode material for enhanced electricity generation and energy storage in microbial fuel cell

The microbial fuel cell (MFC) is an electrochemical electricity generation device that uses microorganisms to degrade organic matter to produce electrical energy. However, due to the limited charge generated by microorganisms, the output power of MFC is relatively low. Additionally, as a traditional MFC, it cannot store charge. In this paper, we designed and developed a dual-function capacitive MFC anode, which could generate electricity and store energy simultaneously. The capacitive anode was prepared by the direct growth of polypyrrole and ferric oxide on the carbon felt matrix, and the two materials played a synergistic effect. The power density of MFC equipped with the CF/PPy/Fe3O4-modified anode reached 6.61 W/m3, 29.8% higher than that of the CF/Fe3O4 anode. When in the charging-discharging 45 min test(C45/D45), the total charge Qt released by the CF/PPy/Fe3O4 anode was increased by 1431.74 C/m2 compared with the CF/Fe3O4 anode. In this paper, the method of preparing a dual-function capacitive bioanode could store the electricity generated by microorganisms in the capacitive anode, which greatly improved the current output of MFC and solved its low output power problem.