The overshoot phenomenon as a function of internal resistance in microbial fuel cells

Winfield, Jonathan; Ieropoulos, Ioannis; Greenman, John; Dennis, Julian

Abstract

A method for assessing the performance of microbial fuel cells (MFCs) is the polarisation sweep where different external resistances are applied at set intervals (sample rates). The resulting power curves often exhibit an overshoot where both power and current decrease concomitantly. To investigate these phenomena, small-scale (1. mL volume) MFCs operated in continuous flow were subjected to polarisation sweeps under various conditions. At shorter sample rates the overshoot was more exaggerated and power generation was overestimated; sampling at 30. s produced 23% higher maximum power than at 3. min. MFCs with an immature anodic biofilm (5. days) exhibited a double overshoot effect, which disappeared after a sufficient adjustment period (5. weeks). Mature MFCs were subject to overshoot when the anode was fed weak (1. mM acetate) feedstock with low conductivity (< 100 μS) but not when fed with a higher concentration (20. mM acetate) feedstock with high conductivity (>1500 μS). MFCs developed in a pH neutral environment produced overshoot after the anode had been exposed to acidic (pH 3) conditions for 24. h. In contrast, changes to the cathode both in terms of pH and varying catholyte conductivity, although affecting power output did not result in overshoot suggesting that this is an anodic phenomenon. © 2011 Elsevier B.V.

• Journal Article Type: Article
• Publication Date: Apr 1, 2011
• Deposit Date: Jun 1, 2011
• Publicly Available Date: Apr 12, 2016
• Journal: Bioelectrochemistry
• Print ISSN: 1567-5394
• Electronic ISSN: 1878-562X
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 81
• Issue: 1
• Pages: 22-27
• DOI: https://doi.org/10.1016/j.bioelechem.2011.01.001
• Keywords: microbial fuel cell, overshoot, polarisation, conductivity; power curve
• Public URL: https://uwe-repository.worktribe.com/output/964219
• Publisher URL: http://dx.doi.org/10.1016/j.bioelechem.2011.01.001
• Additional Information: Additional Information : NOTICE: this is the author’s version of a work that was accepted for publication in Bioelectrochemistry. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Bioelectrochemistry, [81, 1, (April 2011)] DOI: 10.1016/j.bioelechem.2011.01.001
• Contract Date: Apr 12, 2016