Brightman, E; Hinds, G; O'Malley, R* (2013) In situ measurement of active catalyst surface area in fuel cell stacks. J. Power Sources, 242. pp. 244-254.

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Abstract

Estimation of electrochemical surface area (ECSA) of fuel cell electrodes is a key diagnostic of performance and gives a useful parameter for monitoring degradation and state-of-health in polymer electrolyte membrane (PEM) fuel cells. However, conventional methods for determining ECSA require potentiostatic control of the cell, which is impractical in a fuel cell stack. Here we describe a novel galvanostatic technique that makes possible for the first time in situ monitoring of ECSA of electrodes in each cell throughout the lifetime of a stack. The concept is demonstrated at single cell level using both H adsorption and CO stripping. The H adsorption method shows most promise for application in fuel cell stacks, showing good agreement with ECSA values determined using conventional single cell voltammetry across a range of MEA designs. Hydrogen crossover can lead to an under-estimation of ECSA although the effects can be managed by appropriate selection of discharge current and by working with a low H2 concentration on the anode electrode. Although errors in ECSA determination may increase as the fuel cell membrane degrades, when used in combination with other stack diagnostics (such as H2 permeation and short testing), this new test methodology will show trends in cathode decay over the course of stack testing and is expected to become an invaluable tool in lifetime studies.

Item Type:	Article
Subjects:	Advanced Materials Advanced Materials > Fuels Cells
Identification number/DOI:	10.1016/j.jpowersour.2013.05.046
Last Modified:	02 Feb 2018 13:14
URI:	http://eprintspublications.npl.co.uk/id/eprint/5918

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