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NEW GAS DIFFUSION LAYERS FOR FUEL CELLS AND METHOD FOR OBTAINING THEM
WO21198542
The present invention relates to a GDL for PEM-type fuel cells formed by a macroporous substrate layer (MPS) and a porous carbon microlayer (MPL), the MPS being formed by carbon fibres and plant fibres, wherein the plant fibres comprise mostly esparto fibres. Furthermore, the invention also relates to a method for manufacturing the GDLs which comprises: a) Generating a carbon-paper paste using esparto vegetable fibres; b) Filtering; c) Homogenising; d) Cold pressing and compacting the carbon-paper film; e) Curing the carbon-paper film at room temperature for a minimum period of 12 hours; f) Generating the MPS by thermal treatment of the carbon-paper film cured at temperatures no higher than 1,050 degrees C; g) Obtaining the MPL layer; and h) Applying a 2 percent perfluoroexane aqueous solution to the GDL obtained and subsequently curing at 100-150 degrees C for 10-20 minutes.
The new GDLs improve electrical conductivity compared to those existing on the market, thanks to the thermal treatment applied to the porous matrix of the GDL. The incorporation of natural esparto plant fibers into the composition of the porous matrix of the GDLs, which can reach a content of up to 40% in the composition of the GDL. In this way we have found a new application of this natural fiber for the development of a highly technological product, with the advantage that esparto requires less water input in its cultivation, compared to other natural fibers such as cotton. We do not need the use of organic solvents in the manufacturing process of the porous matrix of GDLs, which reduces the environmental impact in its manufacturing process.