GB1185561A - Fuel Cell Anode - Google Patents

Abstract

1,185,561. Fuel cell electrode. ATLANTIC RICHFIELD CO. 18 Jan., 1968 [3 Feb., 1967], No. 2877/68. Heading H1B. A hydrocarbon-reforming fuel-cell anode, Fig. 1, comprises a peripheral spacer support 10 between two metallic hydrogen-permeable membranes 12, 14, forming with the membranes an elongated reaction chamber which is filled with hydrocarbon-reforming catalyst 32, and has an inlet and outlet at opposite ends, the dimensions of the chamber being such as to provide a current density of at least 100 mA/cm.<SP>2</SP> at 0À3 volt anode potential and a fuel utilization efficiency of at least 60% when the electrode is fed with a steam-propane mixture having a steam carbon ratio between 2À33 and 3À33 to 1 in a cell at 250-550‹ C. The support 10 may be of nickel or a ceramic. If of a ceramic, it must include a current collector. The membranes may be of palladium or a palladium alloy, e.g. Pd (75%): Ag (25%), optionally supported on a substrate, e.g. graphite. Their peripheries may be protected by nickel frames 20, 22, the assembly being welded together. The catalyst may comprise either a reduced zirconia promoted nickel on alumina treated with alkali, particles of nickel coated refractory containing 4-70% nickel and 0À5-20% metal oxide, hydroxide or carbonate or nickel-coated alkaline earth metal oxide containing 4-70% nickel. The catalyst particles may be larger than 100 mesh and the thickness of the bed at least four times the average particle diameter. In Fig. 1 the region 24 functions as a heat exchanger between the incoming and outgoing gas. Alternative anode structures are illustrated in Figs. 4-9 (not shown). In a fuel cell, Fig. 3, electrode 28 is immersed in electrolyte 54 between cathodes 44 and 46, the spacing of the electrodes in container 42 is maintained by spacers 47, 48 and 50. The electrolyte may be molten NaOH or KoH or a mixture thereof. A plurality of cells may be joined in series or parallel.