Assessment of a Novel Process to Enable Roll-to-roll Production of Catalyst Coated Membranes

Abstract

Hydrogen is becoming an increasingly important energy carrier within the next few years for many different applications within different industries, such as chemical industry, steel production or mobility. Furthermore, it can be used to store excess energy from renewable energy plants. Within this context, proton exchange membrane-electrolyzer and -fuel cells represent integral parts of this value chain, as they are responsible for hydrogen production and its reconversion to electricity. Both technologies have in common that they need a catalyst coated membrane (CCM) to enable the electrochemical conversion. Since nowadays electrolyzer and fuel cell production is still characterized by small-scale production processes, suitable large-scale production lines will be necessary for the market ramp-up. To address these challenges, a novel coating process for the CCMs is proposed by using a re-coatable transfer belt at which the catalyst ink is coated and dried first. Afterwards, the catalyst ink is transferred onto the membrane by applying a hot-pressing process. Within the presented research, the hot press process is focussed and assessed for the proposed concept. Therefore, the upstream production processes, such as catalyst ink production, coating and drying are described. A design of experiments is then conducted to investigate the applied process parameters within the hot-pressing process and optimized parameters are analysed. Afterwards, re-coating the transfer belt is tested, and the long-term usability of the employed belt is assessed by focussing structural changes.