Correlating Catalyst Ink Rheology with Fuel Cell Performance and Durability

In polymer electrolyte membrane (PEM) fuel cells, catalyst ink formulation and mixing processes are closely related to catalyst layer coating quality, thus affect the fuel cell performance. Therefore, it would be important to understand these complex solvent-catalyst-ionomer interactions to control the ink properties for coating requirements and performance targets. Ink rheological characterization and particle size distribution (PSD) analysis are two powerful tools that can help to extract valuable information of the catalyst ink. This information can be used to optimize electrode morphology and structure to maximize fuel cell performance. In addition, it can also be used to monitor the ink quality and consistency from batch to batch, and from small lab scale to subsequent scale-up as well. To establish the correlation between the ink property and MEA performance, the electrode made of catalyst inks with various rheology have been tested for fuel cell performance and durability. The catalyst inks are varied by ionomer, solvent, catalyst, mixing approach and time. The selection of a variety of non-aqueous solvents for catalyst ink preparation will also be investigated as the solvents impact the catalyst particle morphology and structure, and thus electrode performance. This work will provide a comprehensive understanding of interactions among Pt, carbon, ionomer and their impact on the electrode structure and fuel cell performance. The attained information can be used for better fuel cell electrode design. Acknowledgement: The project is financially supported by the Department of Energy’s Fuel Cell Technology Office under the Grant DE-SC0012049.