The effect of membrane electrode assembly methods on the performance in fuel cells

The rise in interest in fuel cells' technologies increased the number of researchers and publications in the field. The ultimate test of new materials in a lab setup would be in a membrane electrode assembly (MEA), operating under realistic operating conditions (temperature, backpressure, humidity, etc.). The fabrication of the MEA for polymer electrolyte fuel cells (PEFC) is known to greatly affect their performance. Although several good studies were conducted on different parameters in the MEA fabrication, mostly one at a time, there is no comprehensive work on all of the critical parameters required to optimize the fabrication procedure for high performance in one study. Since one parameter may affect another, it is important to optimize all of them together. In addition, the availability of commercial membranes, gas diffusion layers, ionomers and catalysts is constantly changing, and calling for revision of fabrication procedures at an increasing pace. In this work, five different parameters were examined in order to optimize the overall performance of PEFC MEAs: the method of applying the catalyst ink, the hot-press stage, addition of Nafion adlayer on top of the catalyst layer, the compression of the GDE, and finally, the membrane thickness, in order to optimize the full procedure for high performance. The MEAs were tested for several key features in the fuel cell's performance; including the time it takes for the cell to be "broken-in", polarization curves, fuel crossover and charge transfer resistance. A clear optimum was achieved with the ultra-sonic sprayed catalyst ink, with the addition of the ionomer layer, and GDE compression of 43%, while the membrane thickness seems to be a bit less important. (C) 2021 Elsevier Ltd. All rights reserved.