Impact of Catalyst Ink Dispersing Methodology on Fuel Cell Performance Using in-Situ X-ray Scattering
This work presents a study of the effects of ultrasonic dispersing methodology and time on catalyst agglomerate size in polymer electrolyte membrane fuel cell catalyst ink dispersions. Cathode catalyst inks were prepared and characterized to elucidate the influences of ultrasonic dispersing method and time on catalyst ink particle size and CCL electrochemical properties. In situ ultra-small-, small-, and wide-angle X-ray scattering analyses were used to study the impact of ultrasonication time and methodology on changes in the agglomerate, aggregate, and particle size and distribution during the dispersing process. Ex-situ transmission electron microscopy was also used to investigate the particle size of these inks. Fuel cell membrane electrode assemblies (MEAs) were prepared and tested to determine the influence of ink properties on CCL electrochemical properties, including the electrochemical active surface area, mass activity, H2/air polarization curves, and oxygen mass-transport resistances. It was found that a combination of brief tip sonication followed by bath sonication was most effective at breaking up agglomerates, leading to maximum catalyst activity and MEA performance. Extended tip sonication was found to be too aggressive and resulted in detachment of the platinum nanoparticles from the carbon black support, which decreased electrochemical surface area and MEA performance. Quantification of oxygen mass transport resistance showed that electrodes with large catalyst agglomerates due to insufficient sonication had a higher non-Fickian (pressure independent) than properly dispersed catalyst. Through correlation of the performance with catalyst particle size, the desired CCL structure was proposed, which will provide insight into dispersion strategies for lab-scale spray coating and other processing techniques, as well as for large-scale manufacturing.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Advanced Manufacturing Office
- Grant/Contract Number:
- AC36-08GO28308
- OSTI ID:
- 1557081
- Report Number(s):
- NREL/JA-5900-74266
- Journal Information:
- ACS Applied Energy Materials, Vol. 2, Issue 9; ISSN 2574-0962
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Similar Records
Influence of Ink Formulation and Drying Conditions on Ionomer Distribution in High-Performance Roll-to-Roll-Coated Gas-Diffusion Electrodes
Effects of Ink Formulation on the Structure and Performance of PGM-Free Catalyst Layer in PEMFCs