Steven J. Hamrock

The Development of New Membranes for Proton Exchange Membrane Fuel Cells

Recent work at 3M has focused on the development of solvent cast proton exchange membranes (PEMs) for use in PEM fuel cells. These new membranes are a perfluorinated sulfonic acids based on a low molecular weight perfluorinated monomer and they exhibit excellent mechanical properties and chemical stability and high ionic conductivity. The low molecular weight of the monomer allows membranes with equivalent weight as low as 800 g/mole to have good mechanical properties when hydrated. Stabilizing additives in these membranes have been shown to improve the oxidative stability in Fentons tests. Physical property, conductivity and fuel cell tests have been performed. When incorporated into membrane electrode assemblies, these new membranes have provided excellent performance and a greater than 15-fold increase in durability under accelerated fuel cell test conditions, compared with similar commercial PEMs.

Proton Exchange Membrane Fuel Cells: High-Temperature, Low-Humidity Operation

Proton exchange membrane fuel cells (PEMFCs) together with hydrogen represent an important storage and utilization technology for energy generated from renewable sources such as wind, solar, geothermal, or hydroelectric. This is due in part to their high energy density, low operating temperature, rapid start-up, modular design, flexibility of scale (a few watts to hundreds of kilowatts), and the absence of any point-of-use emissions. One barrier to commercialization and widespread acceptance of this technology is cost, a situation fairly common with the introduction of a new technology. Over the past decade much work has been done, and very significant progress has been made, in bringing down the manufacturing cost of fuel cell systems [1]. Manufacturing processes have been optimized, volumes manufactured have increased, less expensive materials have been demonstrated, system efficiencies and power outputs have been increased, and the amount of precious metal catalyst required to generate a kilowatt of power has been reduced dramatically. All of these features have contributed to significant cost reductions. In the case of the precious metal catalysts, one of the major costs, a fuel cell stack that can generate enough power for an automobile can now be built using less than 30 g of platinum catalyst (about 3–4 times as much precious metal as is used in vehicles today), and the auto industry target of 10 g per vehicle appears within reach [2, 3].

V.C.2 Advanced Hybrid Membranes for Next Generation PEMFC Automotive Applications

• Show that heteropoly acid (HPA)-containing films can be fabricated thin and have a low area specific resistance (ASR) at the temperature of an automotive fuel cell stack and at higher temperatures likely to be operational transients whilst also functioning as an electrical resistor. • Increase HPA loading and organization for maximum proton conduction in a functionalized commercial fluoroelastomer manufactured by 3M.