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

Winfield, J., Ieropoulos, I., Greenman, J. and Dennis, J. (2011) The overshoot phenomenon as a function of internal resistance in microbial fuel cells. Bioelectrochemistry, 81 (1). pp. 22-27. ISSN 1567-5394

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Publisher's URL: http://dx.doi.org/10.1016/j.bioelechem.2011.01.001

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 (1mM 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.

Item Type:Article
Uncontrolled Keywords:microbial fuel cell, overshoot, polarisation, conductivity power curve
Faculty/Department:Faculty of Environment and Technology > Department of Engineering Design and Mathematics
ID Code:14779
Deposited By: Dr I. Ieropoulos
Deposited On:01 Jun 2011 10:31
Last Modified:12 Aug 2013 08:05

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