GB1426321A - Membrane electrodes - Google Patents

Abstract

1426321 Fuel cells NATIONAL RESEARCH DEVELOPMENT CORP 14 Feb 1973 [5 Jan 1972 9 Feb 1972] 394/72 and 5971/72 Heading H1B [Also in Division G1] An electrochemical cell includes a solid substrate capable of ionic conduction, a membrane electrode formed directly on the substrate and an active-species permeable membrane formed directly on the electrode. In one embodiment, Fig. 1 (not shown), an electrically insulating cell body has a screw-in portion to which is attached one surface of a planar counter electrode the other surface of which is in contact with a layer of silver rubidium iodide solid electrolyte on to which a platinum layer is deposited as the membrane electrode. Over the platinum layer is deposited a layer of P.T.F.E. which may be protected by a porous disc set into a rubber gasket clamped to the cell body. In Fig. 2 plinth portion 22 of lid 21 contacts a salt bridge layer 23 formed by a dialysis membrane of regenerated cellulose. Platinum layer 24 is deposited on salt bridge layer 23 and is covered by P.T.F.E. layer 25. Liquid electrolyte 26 forms a contact between counter electrode 27 and salt bridge 23. Fig. 4 shows an oxygen-measuring catheter cell in which a silver working electrode 40 insulated at 41 is cemented with silicone resin 42 into a silicone catheter tube 43 leaving a hole which is subsequently filled with a collodionplug salt-bridge 44. Porous layer 45 of gold and silver is deposited on the catheter tip to make electrical contact with silver wire 40 and salt-bridge 44. A silicone oxygen permeable silicone layer 46 on metal layer 45 and tube 43. The cell is completed by a chloride electrolyte solution and counter electrode 48. In an alternative catheter cell, Fig. 3 (not shown), in which the salt-bridge is omitted, the electrolyte is initially collodion containing powdered NaCl, CaCl 2 which is exposed to water vapour prior to use. The cell may be a fuel cell.