(Invited) Impact of Nafion Dispersion Morphology on Fuel Cell Performance and Durability

Los Alamos National Laboratory fuel cell team has discovered that Nafion dispersion morphology in dilute liquid media ca. solid content: 2.5 wt.% has distinctive characteristics, depending on dispersing fluid:[ref. 1] Small angle neutron scattering (SANS) and 19F NMR analysis indicated (i) a well-defined cylindrical dispersion in polyhydric alcohols, (ii) a gel particles that have as open network structure with sufficiently sparse physical network connections in some aprotic dispersing fluids, and (iii) a less-defined highly solvated large particle in water-monohydric alcohol mixtures.

In this talk, we present the impact of dilute Nafion dispersion morphology on film/electrode formation, fuel cell performance and durability. Following subjects will be discussed with some details:

1. Change of particle morphology and gelation behavior of Nafion dispersion during evaporation process (Fig.1).[ref. 2]

2. Characterization of fuel cell electrode by microscopy and electrochemical methods.

3. Impact on fuel cell initial and long-term performance during potential cycles.[ref. 3]

Other critical effects including mechanical toughness of dispersion-cast membranes and electrode reaction uniformity [ref. 4] will be also discussed at the meeting. This presentation will give some insights on recent progress of engineering production and processing of perfluorinated sulfonic acid ionomers and their application for fuel cell membrane and electrode processing.

Acknowledgment U.S. Department of Energy Fuel Cell Technologies Program (Dr. Dimitrios Papageorgopoulos)

References 1. Welch, C.; Labouriau, A.; Hjelm, R.; Orler, B.; Johnston, C.; Kim, Y. S. ACS Macro Letters, 2012, 1, 1403-1407. 2. Kim, Y. S. Welch, C. F. Hjelm, R. P. Mack, N. H. Labouriau, A. Orler, E. B. Macromolecules 2015, 48, 2161-2172. 3. Kim, Y. S. Welch, C. F. Mack, N. H. Hjelm, R. Orler, E. B. Hawley, M. Lee, K. S. Yim, S.-D. and Johnston, C. M. Phy. Chem. Chem. Phy. 2014, 16, (13) 5927-5932. 4. Choi, B., Langlois, D. A. Mack, N. Johnston, C. M. Kim, Y. S. J. Electrochem. Soc. 2014, 161 (12), F1154-F1162.