Thermal Analysis and Cation Doping of Nafion Membranes

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

Name thesis:degree_name

Master of Science

Discipline thesis:degree_discipline

Materials Science and Engineering

Year dc:date.available

2011

Author dc:creator

• Wentworth, Adam J

Contributors dc:contributor

• Dr. Ugur Pasaogullari; Dr. Russell Kunz
• Dr. Trent Molter

• Nafion
• cation
• thermal stability
• sodium
• TGA
• DSC
• FTIR
• PEMFC
• membrane
• degradation

Repository record dc:identifier

https://digitalcommons.lib.uconn.edu/gs_theses/146

OAI identifier oai:identifier

oai:digitalcommons.lib.uconn.edu:gs_theses-1183