High-Capacitance Manganese Dioxide Oxide/Carbon Nanotube/Carbon Felt as a Bioanode for Enhanced Energy Output in Microbial Fuel Cells

Abstract

Microbial fuel cell (MFC) technology can potentially recover bioelectricity from wastewater. However, its practical applications have been limited because of its low power density and since the energy generated from an MFC cannot be stored. In this study, manganese dioxide (MnO2) coupled with carbon nanotubes (CNT) was chosen to in situ modify carbon felt (CF) as a capacitive bioanode (CF/CNT/MnO2) to improve the power generation and energy storage of MFCs. The maximum power density of the MFC with the MnO2-CNT-modified bioanode reached 3471.6 mW m3, which was 1.96 times higher than that of the CF/CNT anode (1772.6 mW m−3). During the experiment of charging for 30 min and discharging for 30 min, the MFC with a capacitive bioanode had a total charge of 8777.1 C m−2, 2.74 times higher than that of the CF/CNT anode. The excellent electricity-producing and energy storage performance of the MFC equipped with the CF/CNT/MnO2 anode is attributed to the composite materials, which can be due to their better biocompatibility, large capacitance, and high specific surface area. This study provides a new way to improve the performance of electricity generation and energy storage of MFCs.