Fuel cells and fuel cell electrodes

Sutherland, Hugh (2014) Fuel cells and fuel cell electrodes. GB2510962 (A).

Abstract

Electrodes for liquid electrolyte fuel cells comprise a sheet 11 of metal through which are defined a multiplicity of through-holes 14, and a hydrophobic gas-permeable layer 16 of fibrous and/or particulate electrically-conductive material which is bonded to and in electrical contact with the sheet of metal 11. To the outer surface of the gas-permeable layer 16 is bonded a hydrophobic catalyst-containing layer 18, preferably of similar thickness and less hydrophobic than the first layer 16, and to the outer surface of the catalyst-containing layer 18 is bonded a hydrophilic layer 20, such as carbon paper. The components can be assembled by hot pressing, starting with the layers 16 and 18 in a wet state containing the binder polymer in suspension; the hot pressing evaporates the liquid components and sinters the polymer binder, so bonding the layers 16, 18, 20 together and to the sheet 11. The electrode is provided as part of a liquid electrolyte fuel cell (200, fig 2), preferably an alkaline fuel cell, comprising means to define an electrolyte chamber (208, fig 2), and two electrodes 10, one on either side of the electrolyte chamber. The electrode 10 may be arranged in the fuel cell such that the hydrophilic layer 20 faces the electrolyte chamber (208, fig 2), and the metal sheet 11 is adjacent to a gas chamber (207 or 209, fig 2).