MULTIVARIATE OPTIMIZATION OF THE FABRICATION PROCEDURE OF POLYMER ELECTROLYTE FUEL CELL ELECTRODES

Various procedures for the fabrication of membraneelectrode assemblies (MEAs) for polymer electrolyte fuel cells (PEFC) have been reported in the literature; all of these procedures were optimised by studying the effects on PEFC performances of fabrication parameters, experimenting the effect of each variable with OVAT (one variable at a time) experimental planes. Such a univariate experimental approaches do not allow evaluating the effects of mutual interactions between fabrication parameters and requiring large number of experiments, with consequent waste of time and materials. On the other hand, MEA’s preparation procedures need to be frequently verified, due the continuing evolution of the materials available and to maximise performances under particularly demanding conditions, such as low temperature and diffusive oxidant supply.
The experimental design statistical technique provides the maximum information about the system under study, with the minimum number of experiments but no description of its application to MEAs fabrication has yet been reported in the literature In this work, the experimental design technique was used to evaluate the effects of MEA's fabrication parameters, for use in low-temperature, hydrogen fuelled PEFC. The effects of the contents of Pt-carbon catalyst and Nafion ionomer in the catalyst layer, and Vulcan carbon black and Teflon in the diffusion layer, were studied by preparing MEAs whose composition was varied according to a fractional experimental design.
The MEAs obtained were experimented for the fabrication of an air-breathing, hydrogen fuelled PEFC operating at room temperature.