Electricity generation and storage in microbial fuel cells with porous polypyrrole-base composite modified carbon brush anodes. (December 2020) - Wang, Yuyang
Abstract: Microbial fuel cells (MFCs) equipped with three-dimensional (3D) electrodes are widely used in wastewater treatment. However, the power output and energy storage of MFCs with 3D anodes are still limited in application. Here, a biocompatible, capacitive, and adhesive polypyrrole, carboxymethyl cellulose, carbon nanotube/carbon brush (PPy-CMC-CNTs/CB) material was prepared, that was integrated into a composite to obtain a high-capacitance 3D anode. An SEM showed that the composite anode had a 3D-macroporous structure that had a large surface area, providing more places for the attachment and growth of microorganisms. The power density of the MFC with a PPy-CMC-CNTs/CB composite anode (2970 mW/m 2 ) was 4.34 times greater than that of an MFC with a bare anode (683 mW/m 2 ). In the tests with a charge for 15 min and discharge for 45 min, it was observed that the stored charge of the bioanode (333 mC/cm 2 ) was 23.67 times higher than that of the bare anode (14.07 mC/cm 2 ). High-throughput sequencing revealed that the modified composite anode had excellent biocompatibility and selective enrichment of electrogenic bacteria. This study provided a simple and environmentally-friendly modification to enable a PPy-CMC-CNTs/CB composite anode to promote energy storage and output performance of MFCs. Graphical abstract: Image 1 Highlights: A biocompatible, capacitive, and adhesive PPy-CMC-CNTs/CB composite anode was prepared. The power density of the modified anode was 4.34 times as much as that of the bare anode. CMC was used as an adhesive among carbon brush, CNTs, and PPy.