Nafion Membranes Reinforced with Ceria-Coated Multiwall Carbon Nanotubes for Improved Mechanical and Chemical Durability in Polymer Electrolyte Membrane Fuel Cells

Abstract

A composite membrane consisting of a Nafion proton exchange ionomer and ceria-coated multiwall carbon nanotubes (MWCNTs) was prepared by a solutioncasting method. Reinforcement due to the presence of MWCNTs provides increased mechanical strength to the membrane, and the addition of ceria improves the membrane's chemical durability by scavenging free radicals. The ceria coating also insulates the MWCNTs, which helps to preserve the membrane's low electrical conductivity in the through-thickness direction. The morphology and loading of the CeO 2 /MWCNT precursor were verified using transmission electron microscopy and thermogravimetric analysis. The mechanical and chemical durability of the synthesized composite [CeO 2 / MWCNT]/Nafion membranes was compared with that of pure Nafion membranes. Composite membranes demonstrated improved tensile strength and dimensional stability during hydration, without significantly affecting electronic or ionic conductivity, and maintain equivalent polarization performance in a fuel cell system. They also showed increased durability in an open-circuit-voltage-hold fuel cell test. Such material property enhancements can extend the membrane lifetime, which increasing the economic viability of fuel cell technology.

Sulfonated graphene oxide/Nafion composite membranes for high temperature and low humidity proton exchange membrane fuel cells

“…Aerward, the water on the surface of membranes was carefully blotted with tissue paper and mass, length and thickness of membranes were measured again. 5,28 The measurement was repeated three times for each membrane using different specimens, and the average value was used for calculation. % of changes in mass, length and thickness were calculated using the eqn (3)- (5):…”

Toward improved mechanical strength, oxidative stability and proton conductivity of an aligned quadratic hybrid (SPEEK/FPAPB/Fe3O4-FGO) membrane for application in high temperature and low humidity fuel cells

“…16 Altogether, these issues result in cyclical swelling and shrinking of SPEEK membrane (high DS), and consequently lead to high perviousness of hydrogen and mixed potential with oxygen. These may adversely minimize the PEFC efficiency by inefficient fuel usage and reducing the cell voltage.…”

Cerium Migration during PEM Fuel Cell Accelerated Stress Testing

“…1,2,29,30 Cerium stabilization of MEAs results in lower fluoride emission rates (FERs) compared to unstabilized MEAs, which indicates reduced PEM thinning and pinhole development. [12][13][14][15][16][17][18][19][20][21][22][23][24][25] As a result, cerium-stabilized MEAs maintain more stable gas crossover rates and extended AST lifetimes, which confirm its ability to enhance chemical and mechanical durability in situ.…”