Progress of catalyst layer coating techniques for polymer electrolyte membrane fuel cell performance: A review

The nanostructure-engineering of catalyst layers signifies a fundamental technology in the fabrication of membrane electrode assemblies (MEAs) for polymer electrolyte membrane fuel cells (PEMFCs). Firstly, the design and working principles of MEAs for PEMFCs are elaborated briefly. Specifically, the porous media, membrane, and catalyst layer (CL) are further explained in the literature to understand the principal functions of MEAs. This review paper describes and summarizes the progress and developments of CL coating techniques, with an emphasis on their impact on transport properties and overall cell performance. The transport of protons, electrons, reagents, and products is heavily influenced by the process parameters adopted during the preparation of CLs. This work aims to facilitate process selection through evaluation of a variety of coating techniques for alternative power sources of PEMFCs. Lastly, this paper highlights that future progress will be facilitated by an understanding of how coating techniques have evolved in response to challenges and how they can be further developed to reach high PEMFC performance through fabrication CL to pave way for commercialization. The results of this work demonstrate that during the CL coating process, catalyst ink dispersion, platinum (Pt) usage, and agglomeration of catalyst particles must be carefully addressed. These findings can be useful for both academic and industrial researchers to ensure high-quality control in electrode fabrication.