Date of Completion
Cationic contamination degrades polymer electrolyte membrane fuel cell
(PEMFC) performance by decreasing proton conductivity and water content in
perfluorosulfonic membranes such as Nafion. Hydration of the membrane is important
for cell durability and longevity; low relative humidity accelerates membrane
degradation. Cations can exchange with the proton on the sulfonate group in the polymer
and modify exchange site properties.
In an effort to build upon the existing knowledge of polymer electrolyte
membrane fuel cell (PEMFC) contamination effects, characterization of Nafion 117 and
212 in proton and sodium form has been performed. An emphasis has been placed on
sodium because it is found in close proximity to automobiles on roads and marine
environments, and in large enough quantities to potentially contaminate membrane
materials. High diffusivity, thermal stability, and existing research make sodium an
important cation. Cations Li+, K+, Cs+, Ca2+, Ni2+, and Cr3+ have been studied for
comparison. Virgin and used gas diffusion layer (GDL), catalyst coated membrane
(CCM), and uncatalyzed membrane (UCM) materials were examined to aid in single cell
post-test characterization where separation of materials is difficult and may alter results.
Through thermal analysis, FTIR, and vapor sorption the study shows how
membranes of salt form differ in water content, freezable water, water cluster structure,
water diffusion, and decomposition. Membranes of varying thickness in acid and sodium
form have been tested in vapor sorption and FTIR for comparison.
Wentworth, Adam J., "Thermal Analysis and Cation Doping of Nafion Membranes" (2011). Master's Theses. Paper 146.