Electro-polymerized polyaniline modified conductive bacterial cellulose anode for supercapacitive microbial fuel cells and studying the role of anodic biofilm in the capacitive behavior

Polyaniline modified conductive bacterial cellulose (BC-CNT-PANI) membrane is proposed as a novel bioanode for microbial fuel cell (MFC). BC is coated with CNT by vacuum filtering to form a conductive electrode (BC-CNT). Then the conductive side is coated with PANI through a fast and easy electro-polymerization (BC-CNT-PANI). Both anode electrodes are studied in supercapacitive MFCs (SCMFCs) by impedance analysis before and after biofilm formation on their surface. By bacteria colonization on the anodes’ surface, charge transfer resistance (Rct) of BC-CNT increases significantly from 14.5 Ω to 72 Ω while for BC-CNT-PANI, Rct decreases by 50%. Also, after biofilm formation, BC-CNT-PANI achieves a capacitance two times higher than that of BC-CNT. The SCMFCs are assembled and tested with BC-CNT, BC-CNT-PANI, and the double-anode BC-CNT& BC-CNT-PANI. Polarization, power density and galvanostatic discharge tests imply on an improvement in the SCMFC performance by using BC-CNT-PANI. The performance of the SCMFCs are limited by the anodes. The power density improves by 20% with the PANI-modified anode compared to the BC-CNT.