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There is increasing interest in the alkaline exchange membrane (AEM) fuel cells as this device, if realized, could allow the use of inexpensive metal catalysts and the oxidation of a variety of convenient liquid fuels. While there have been some dramatic early achievements, there is still a need for a fundamental study of anion transport, cation stability and the formation of robust thin films in this area. We have undertaken a comprehensive study of AEMs where theory is linked to well-defined model systems, both in solution and in the solid state, which are characterized using very careful environmental control such that the models can be validated and used predictively. We are also fabricating a number of random copolymer AEMs that can be produced readily in large quantities, allowing us to understand film formation coupled with transport and stability. Those based on perfluorinated backbones invite interesting comparisons with the analogous proton exchange membranes.

A new class of cathode catalysts based on supportless Pt nanotubes (PtNTs) and Pt alloy nanotubes with remarkable durability and high catalytic activity have been developed. Due to their unique combination of dimensions at multiple length scales, the PtNTs can provide high Pt surface area by their nanometer-sized wall thickness and have the potential to eliminate or alleviate most of the degradation pathways of the commercial carbon supported Pt catalyst (Pt/C) and unsupported Pt black as a result of their micrometer-sized length. The PtNTs asymptotically approaches a maximum of ~20% Pt surface area loss in durability test, while the commercial PtB and Pt/C loses about 51% and 90% of their initial surface area, respectively. Moreover, the PtNTs and PtPdNTs show much higher specific activity than commercial Pt/C.

The durability of Pt supported on cup stacked carbon nanotubes (CSCNTs) was investigated with an accelerated test using cyclic voltammetry as a tool. The loss in electrochemically active surface area is compared with that of an E-TEK Pt/Vulcan XC-72 carbon catalyst. The relatively lesser surface area loss in case of Pt/CSCNT catalyst is attributed to better corrosion resistance of CSCNTs. A preliminary data on the durability of cup stacked carbon nanotubes based membrane electrode assembly is presented.

Zeolites are microporous crystalline aluminosilicates with uniform and molecular sized pores. We have been investigating the application of zeolite films as chromium-free protective coatings on aluminum alloys. We have shown that as-synthesized organic template containing high-silica-zeolite (HSZ) MFI coatings on AA-2024-T3 are non-porous and have excellent corrosion resistance in strong acids, bases, and pitting aggressive media. We have also shown that the in-situ crystallization coating deposition process we used can coat surfaces of complex shapes and in confined spaces. Only one simple pretreatment and a single zeolite formulation are needed to synthesize MFI coatings on several different aluminum alloys. In this paper we show salt-fog accelerated weathering tests performed according to ASTM B117 on 7.5 um thick HSZ MFI coated 2024-T3 and their DC polarization profiles in 5 wt% NaCl aqueous solution. All HSZ MFI coated AA-2024-T3 panels were considered passing after more than 2000 hours continuous salt fog exposure.

There is increasing interest in the alkaline exchange membrane (AEM) fuel cells as this device, if realized, could allow the use of inexpensive metal catalysts and the oxidation of a variety of convenient liquid fuels. While there have been some dramatic early achievements, there is still a need for a fundamental study of anion transport, cation stability and the formation of robust thin films in this area. We have undertaken a comprehensive study of anion transport and AEMs where theory is linked to well-defined model systems, both in solution and in the solid state, which are characterized using very careful environmental control such that the models can be validated and used predictively. We are also fabricating a number of structured copolymer AEMs that can be produced readily in large quantities, allowing us to understand film formation coupled with transport and stability.