Up-Scaled Preparation of Pt–Ni Aerogel Catalyst Layers for Polymer Electrolyte Fuel Cell Cathodes

High activity and durability are two key requirements for the successful development of Pt-based ORR catalyst layers for polymer electrolyte fuel cell (PEFC) cathodes. Unsupported Pt–Ni aerogels consisting of an interconnected nanoparticle network have been shown to fulfill these two requirements, but in our previous work, their processing into high-performing catalyst layers (CLs) required the inclusion of a pore inducer and the preparation of catalyst-coated membranes (CCMs) through hand spraying. Since the results of the latter approach are highly dependent on the operator and therefore prone to irreproducibility, in this work, we attempted to use an automated spray coating machine to reproducibly manufacture aerogel CCMs. This required scaling up the aerogel synthesis (yielding 5-fold more material than in previous works), which was shown to yield a material with physicochemical properties similar to those of the aerogels made through the standard approach. Most importantly, the subsequent optimization of the catalyst ink formulation and processing methods resulted in homogeneous and high-performance CLs without the use of a pore inducer. Thus, this work represents an important step toward the up-scaling of such materials' synthesis in the (multi)gram scale and their subsequent implementation in real devices.