Examination of SWMC applying method by spray coating method for PEFC

Abstract

A popularization of Polymer Electrolyte Fuel Cell (PEFC) is necessary to realize ahydorgensociety. However, the manufacturing cost is still expensive, and it is required to reduce the manufacturing cost for further spread. In our laboratory, we have been developing 3D catalyst layers using ink-jet printers (IJP) and self-water management catalyst layers (SWMC) by adding carbon grains in order to reduce the amount of platinum catalysts used while maintaining the power generation performance. The IJP method can form a catalyst layer with a three-dimensional structure, but its disadvantage is that it cannot coat our proposed SWMC, due to the long coating time and small nozzle diameter. Therefore, in this study, we investigated the possibility of producing SWMC by the spray coating method in order to shorten the coating time and enable the application of carbon additives. As a result, Although it was confirmed that the spray coating method was able to disperse and apply the added carbon grains, the polarization resistance was worse than that of the IJP method. The polarization resistance of the catalyst layer with spherical graphite was hardly different with that of the standard catalyst layer, consequently it was confirmed its effectivness. On the other hand, graphite rubbish increased polarization resistance drastically by damaging the polymer membrane during the spray application process, inducing cross leakage.