Membrane electrode assembly targets

Cost targets exist for all parts of the fuel cell for bipolar plates, from 10/kW (2004) to 3/kW in 2015 for electrocatalysts, from 40/kW (2005) to 3/kW in 2015 and for membrane electrode assemblies (MEA), from 50/kW (2005) to 5/kW in 2015 (Freedom Car, 2005 these cost targets are somewhat different from those mentioned by the IEA (2005)). Since 2004, the number of fuel-cell cars has been growing and at the time of writing they numbered approximately 1000 worldwide there are also around 100 fuel-cell buses in use worldwide in several demonstration projects. But these cars are produced as individual (hand-built) models and are extremely expensive, with production costs per vehicle currently estimated at around one million large-scale production is not expected before 2015, see Section 13.1. 

Demonstrate proofs of concept for the large-scale preparation of high performance electrodes for membrane electrode assemblies (MEAs) and assess electrode and MEA architecture against FreedomCAR cost targets. 

Since Pt is a scarce and expensive metal, in 2002, the US Department of Energy (DOE) set targets for the maximum quantity of Pt to be used in H2/O2 (Air) PEM fuel cells. Initially, the 2015 target was set to 0.2 g Pt/kWe (with kWe for the rated electric power) for total anode and cathode Pt content combined. However, due to the considerable rise in Pt price, a new target—0.125 g Pt/kWe—was recently set for 2017 [5]. At around 1,700-1,800 per Pt Troy ounce (31.1 g), 0.125 g Pt/kWe would represent a Pt raw material cost of around 7 Pt/kWe. Meanwhile, the DOE also sets the cost target for the entire membrane electrode assembly to 9/kWe There is, therefore, a strong case for replacing Pt with a lower cost non-noble metal-based electrocatalyst (or a metal-free electrocatalyst). 

Chapters 6 and 7 deal with the hydrocarbon polymers and composites targeted for high temperature PEM fuel cell applications. Specifically, chapter 6 deals with a series of high molecular weight, highly sulfonated poly(arylenethioethersulfone) (SPTES) polymers synthesized by polycondensation. They were characterized by different methods and tested for proton conductivity. Finally, membrane electrode assemblies (MFAs) were fabricated. 

What one can consider as the first electrochemical sensor, i.e., a modified electrode surface dedicated to a specific target analyte, was a platinum electrode, covered by a protective membrane, the Clark electrode, for the determination of O2 in blood.The first biosensor was based on the determination with such Clark electrode of O2 depletion induced by glucose oxidase activity in the presence of glucose.These two examples show the importance of platinum as electrode material. It will be seen below that gold was also widely used for the development of chemically modified electrodes, especially due to the strong interaction with thiol-functionalized organic molecules allowing the formation of self-assembled monolayers (SAM). ... 

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