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Fuel cells are thought to be one of the future solutions to the 'energy crisis', providing “clean” electricity. The development of fuel cells is considered to be an integral part of a sustainable ‘hydrogen economy’, in which hydrogen gas is produced using renewable sources of energy, and which offers the possibility of abundant energy with negligible emissions. Another advantage of fuel cells lies in the high efficiency to convert chemical energy into electricity and heat (hot water). Today, two kinds of fuel cells are expected to be attractive for many applications: 1) Proton Exchange Membrane Fuel Cell (PEMFC, or more generally, Solid Polymer Fuel Cell SPFC which includes Direct Methanol Fuel Cell –DMFC-, Direct Ethanol Fuel Cell –DEFC-) and 2) Solid Oxide Fuel Cell (SOFC). Each is constituted by two electrodes and a solid electrolyte (membrane) in between. Fuel cell efficiency strongly depends on this electrode-membrane-assembly.
PEMFC systems provide an order of magnitude higher power density than the other fuel cell systems. The PEMFC can operate with reformed hydrocarbon fuels, after pre-treatment, and with air. The use of a solid polymer electrolyte eliminates the corrosion and safety concerns associated with liquid electrolyte fuel cells. Its low operating temperature of 80ºC provides instant start-up and requires no thermal shielding to protect personnel. Recent advances in performance and design offer the possibility of lower cost than any other fuel cell system. The PEMFC is a very promising device for mass market applications such as automotive and stationary small scale “combined heat and power” applications.
New materials and new related synthesis processes are required to improve fuel cell efficiencies and costs. Among many methods, plasma deposition is a promising technique for elaborating these fuel cell materials. We will focus on PEMFC for which low pressure plasma deposition is expected to improve membrane characteristics (especially higher operating temperature using new polymer electrolyte thin films) and electrode structure by properly controlling the content, morphology and profile of the expansive catalyst used.
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