Electrochemical and impedance characterization of Microbial Fuel Cells based on 2D and 3D anodic electrodes working with seawater microorganisms under continuous operation

Abstract

A mixed microbial population naturally presents in seawater was used as active anodic biofilm of two Microbial Fuel Cells (MFCs), employing either a 2D commercial carbon felt or 3D carbon-coated Berl saddles as anode electrodes, with the aim to compare their electrochemical behavior under continuous operation. After an initial increase of the maximum power density, the felt-based cell reduced its performance at 5 months (from 7 to 4 μW cm⁻²), while the saddle-based MFC exceeds 9 μW cm⁻² (after 2 months) and maintained such performance for all the tests. Electrochemical impedance spectroscopy was used to identify the MFCs controlling losses and indicates that the mass-transport limitations at the biofilm-electrolyte interface have the main contribution (>95%) to their internal resistance. The activation resistance was one order of magnitude lower with the Berl saddles than with carbon felt, suggesting an enhanced charge-transfer in the high surface-area 3D electrode, due to an increase in bacteria population growth.

Key findings

• ▸MFCs with 3D anodic electrodes exhibit higher power density and coulombic efficiency compared to 2D electrodes.
• ▸Seawater microorganisms demonstrate stable and efficient operation in MFCs under continuous operation.
• ▸Impedance analysis reveals improved electrochemical performance of MFCs with 3D anodic electrodes.

Keywords

Identifiers

DOI

10.1016/j.biortech.2015.06.127

PubMed

26166463

Journal

Bioresource Technology

Year

2015