Process Development for the Fabrication of Membrane Electrode Assemblies for Polymer Electrolyte Membrane Water Electrolyzer

The importance of energy storage to balance the intermittent supply of energy with the demand, promotes interest in the conversion and storage of renewable energy. Hydrogen is identified as an energy carrier, and water electrolysis is one of the techniques to produce it in a sustainable and environmentally friendly method. The use of this hydrogen in fuel cell systems ensures an overall eFicient use of the clean energy system. However, high manufacturing cost and uncertainty about future cost and performance improvements are constraints to the investment in water electrolysis and fuel cell technology. This work addresses the issues of better utilization of the catalyst material in an attempt to reduce the material losses during the membrane electrode assembly (MEA) production and to develop a better controlled procedure for reproducibility in the manufacturing, without significantly reducing the performance and eFiciency of the components. The approach highlights on an improved MEA production method to automate the manufacturing process. A prominent alternate approach to MEA fabrication (direct catalyst deposition/coating on the membrane - CCM via Nanodispenser) has been tested in this work. It offers the advantage of higher controlled ink deposition onto the Nafion membrane, mainly through the drop-on-demand approach. This mode of ink-jet printing aims to achieve higher flexibility and quality in MEA production and to be able to lead to higher homogeneity of the catalyst layer. Initially, a printing process is developed for the anode side CCMs for the MEA (active area of 4 cm2) of Proton Electrolyte Membrane Water Electrolyzer (PEMWE) with the use of subsequent chronology of bitmaps for catalyst ink deposition. The process is later optimized for faster printing speed and improved performance of the MEA in terms of higher current density. The different parameters such as catalyst ink concentration, dispersion energy, thermal treatment temperature, Nafion ionomer content that influence the overall process are examined individually and the optimized values of the parameters are combined to deliver a high performing MEA which achieved a current density of 4200 mA/cm2 at 2.5 V for a catalyst loading of 0.94 mg/cm2. The significant advantage of the process was the 80% reduction in the catalyst material used than in the conventional spray coating technique. However, for production scale-up and a smooth operation of the system, it requires evaluation of ink rheological properties and a formulation technique suitable for higher ink stability. The binder content for the OER catalyst for MEAs employed in PEMWE, should be analyzed further to derive an optimal quantity