Interfacial Water-Transport Effects in Proton-Exchange Membranes

Journal Article · Thu Nov 19 04:00:00 EST 2009 · Journal of Fuel Cell Science and Technology

OSTI ID:979809

Kienitz, Brian; Yamada, Haruhiko; Nonoyama, Nobuaki; Weber, Adam

It is well known that the proton-exchange membrane is perhaps the most critical component of a polymer-electrolyte fuel cell. Typical membranes, such as Nafion(R), require hydration to conduct efficiently and are instrumental in cell water management. Recently, evidence has been shown that these membranes might have different interfacial morphology and transport properties than in the bulk. In this paper, experimental data combined with theoretical simulations will be presented that explore the existence and impact of interfacial resistance on water transport for Nafion(R) 21x membranes. A mass-transfer coefficient for the interfacial resistance is calculated from experimental data using different permeation cells. This coefficient is shown to depend exponentially on relative humidity or water activity. The interfacial resistance does not seem to exist for liquid/membrane or membrane/membrane interfaces. The effect of the interfacial resistance is to flatten the water-content profiles within the membrane during operation. Under typical operating conditions, the resistance is on par with the water-transport resistance of the bulk membrane. Thus, the interfacial resistance can be dominant especially in thin, dry membranes and can affect overall fuel-cell performance.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: Environmental Energy Technologies Division
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 979809
• Report Number(s): LBNL-2862E
• Journal Information: Journal of Fuel Cell Science and Technology, Journal Name: Journal of Fuel Cell Science and Technology; ISSN 1550-624X
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
30 DIRECT ENERGY CONVERSION
33 ADVANCED PROPULSION SYSTEMS
36 MATERIALS SCIENCE
97 MATHEMATICS AND COMPUTING
HUMIDITY
HYDRATION
MANAGEMENT
MASS TRANSFER
MEMBRANES
MORPHOLOGY
PERFORMANCE
PROTON EXCHANGE MEMBRANE FUEL CELLS
Proton-exchange membrane
fuel cell
interfacial resistance
water transport
TRANSPORT
WATER