Sulzer Hexis Ag

Sulzer Innotec Ag

Hexis Ag

Emad Batawi

Andreas Franz-Josef Kaiser

Gilles Robert

Kaspar Honegger

John Antony Peters

Bruno Doggwiler

Cyril Voisard

Alessio Plas

The structured body intended for use for an anode () in fuel cells, includes a structure formed by macro-pores and an electrode material. The macro-pores form communicating spaces which are produced by using pore forming materials. The electrode material includes skeleton-like or net-like connected structures of particles which are connected by sintering and which form two reticular systems which interengage: a first reticular system made of ceramic material and a second reticular system which contains metals to effect an electrical conductivity. The electrode material has the properties so that, with a multiple change between oxidizing and reducing conditions, substantially no major property changes occur in the ceramic reticular system, and an oxidization or reduction of the metals occurs in the second reticular system.

Structured body for an anode used in fuel cells

Porous structured body for a fuel cell anode

Anode material for a fuel cell which is to be operated at a high temperature above 700&#xb0; C., which anode material is a porous composite material with a heterogeneous phase of solid materials which is formed by two reticular systems which penetrate each other in interlaced manner of particles connected by sintering, namely a first reticular system of ceramic material, and also a second reticular system of metallic material for the purpose of bringing about redox processes and an electrical conductivity, characterized in that the first reticular system is composed of large and small ceramic particles () with average diameters dgreater than 5 &#x3bc;m or smaller than 1 &#x3bc;m respectively, in that 50% to 80% of the first reticular system is formed from the large ceramic particles (), and in that a composition of the anode material to be used is given by values which are selected by means of samples of this material and a test method, wherein the test method includes at least one redox cycle, an irreversible change in length of the selected sample adopting in this a value smaller than 0.002, preferably smaller than 0.0005, and the following measurements and evaluations being carried out per redox cycle at a temperature which is at least the same as the operating temperature of the fuel cell:

Anode material for a high temperature fuel cell

The porous, gas permeable layer substructure () for a thin, gas tight layer () can in particular be used as a functional component in high temperature fuel cells (). This layer substructure has a smooth surface () which is suitable for an application of the gas tight layer or a multi-layer system including the gas tight layer, with the application being carried out by means of a screen printing method or other coating methods. The smooth surface is formed by a compacted edge zone (). The edge zone and a carrier structure () adjacent to this are made from sinterable particles of a uniform substance mixture. The porosity of the carrier structure is greater than 30 volume percent, preferably greater than 40 volume percent. The pore size of the edge zone is smaller than 10 &#x3bc;m, preferably smaller than 3 &#x3bc;m.

Porous, gas permeable layer substructure for a thin, gas tight layer for use as a functional component in high temperature fuel cells

The disclosure concerns a method of preparing an ink (P) which can be used for the manufacture of a functional layer (), in particular for the manufacture of an electrode for fuel cells, which ink contains dispersely distributed particles () forming two solid phases, with catalytic reactions being able to be activated in the manufactured functional layer on a gas/solid interface by a combined action of the two solid phases and with gaseous reactants. In a first step (), the solid phases are formed as fine-grain particles (P, P) and the particles of both solid phases are dispersed in a first liquid (L) in a mixed and homogeneously distributed manner (). Heterogeneous conglomerates (P) of the fine-grain particles are formed from the thereby created dispersion (D); these conglomerates are mixed to form a homogeneous ink (P), after sintering (), by addition of a second liquid (L) and by comminution (), with particles formed in the first step having such a fine grain that the heterogeneous conglomerates and their fractions each contain a plurality of particles of both solid phases after comminution.

Method of preparing an ink

A fuel cell having a solid electrolyte layer () forms together with two electrode layers () a plate-like multiple layer system (). The layers are applied by means of coating procedures to an open-pored, electrically conducting carrier structure () in the sequence anode (), electrolyte () and cathode (). This multiple layer system () has an outer edge which is exposed during a current generating operation of the fuel cell to an external environment () which contains molecular oxygen. The material of the carrier structure assumes an oxidized or a reduced state in thermodynamic equilibrium at the operating temperature of the fuel cell depending on the environment. The outer edge () of the multiple layer plate is covered over with an inert material. At the operating temperature of the fuel cell this edge covering () forms a barrier which inhibits or prevents the transport of molecular oxygen out of the external environment () into the carrier structure. The material is in particular YSZ, i.e. zirconium dioxide ZrOwhich is stabilized with yttrium oxide YO.

Fuel cell comprising a solid electrolyte layer

Fuel cell battery with a stack of planar cells

The interconnector (,) for high temperature fuel cells is arranged between a first and a second planar electrochemically active element (,). In this it separates a chamber (,) containing a combustion gas from a chamber (,) containing oxygen. A porous sinter body (,) of the interconnector has pores (,) which are at least partly sealed by a medium (,). Through the sealing, a passage of gases between the named chambers (,) is prevented.

Interconnector for high temperature fuel cells

The electrochemically active element (1) for a high temperature fuel cell is designed in the form of layers and comprises an anode layer (3), a cathode layer (4) and an electrolyte layer (2) which is arranged therebetween. The electrolyte is a ceramic material of zirconium oxide ZrO,stabilised with yttrium Y which can additionally contain aluminium oxide Al,O,. The anode is manufactured from a power mixture through sintering on the electrolyte layer. This anode mixture contains the oxides NiO and CeO2 and can contain an oxide of the type A,O,, with for example A&equals;Sm, Y, Gd and/or Pr. In accordance with the invention 0.5&minus;5,/,CoO, FeO and/or MnO is or are to be added to the anode mixture in order to lower the sintering temperature of this mixture.

Electrochemically active element for a high temperature fuel cell

Perowskite for a coating of interconnectors

The high temperature fuel cell with a thin film electrolyte has an electrochemically active element which is executed as a planar multi-layer structure. At least the electrolyte and cathode layers are deposited on a porous, gas-permeable carrier structure, by means of a thin film technique. The carrier structure is a sintered body of metal ceramic material which comprises a highly porous base layer as well as a fine pored cover layer of anode material placed on the base layer. The pores of the base layer are open with respect to one another and have an average diameter of the order of magnitude of at least about 300 .mu.m. The pores of the cover layer have diameters which are not substantially greater than 1 to 3 .mu.m. The coefficient of thermal expansion of the carrier structure is substantially the same as that of the solid electrolyte.

High temperature fuel cell with a thin film electrolyte

The battery with planar high temperature fuel cells comprises a stack-shaped, alternating arrangement of electrochemically active elements and interconnectors. The interconnectors are formed as air heat exchangers, each of which has a basic body. The thermal expansion of the interconnector is largely determined by the basic body. Each basic body separates an air side from a gas side. A structured layer is arranged on both sides of the basic body in each case: namely a structured layer for electrical conduction and heat transport as well as for a transport of air or combustion gas respectively along the electrochemically active elements. The thermal expansion of the basic body corresponds substantially to that of the electrochemically active elements. Each basic body is formed as an air heat exchanger and consists of a material on whose surface a permanent oxide layer forms under the operating conditions of the battery and in the presence of oxygen. On the air side of the basic body, the structured layer is bonded to the basic body in such a manner that the basic body is protected against oxide formation at the connection points.

Battery with planar high temperature fuel cells

A high temperature fuel cell has a planar substantially centrally symmetrical structure. It includes an electrochemically active plate and an interconnector formed as an air heat exchanger. The air infeed positions are arranged at the periphery of the cell. The interconnector is built up in three layers: the middle layer consists of a plate which has at least approximately the same thermal expansion as the electrochemically active plate, and the side layers are formed of metal sheets which are substantially thinner than the plate of the middle layer. The metal sheets have a relief-like structure and are firmly connected to the middle plate via a plurality of contact positions. The metal side sheets are designed for a direct contact with the electrochemically active plate and the corresponding plate of a neighboring cell.

High temperature fuel cell

A parting compound in the form of a monolithic component (3a, 3b) is used in accordance with the invention for the hot forming of encased metal parts (2). This component consists of powder particles strengthened by sintering. The parting compound material is brittle at ambient temperature and at the deforming temperature of the metal parts is plastically deformable or free flowing in a highly viscous manner.

Parting compound for the hot forming of encased metal parts and a

The method makes possible the production of iron aluminide raw materials which consist of a Fe.sub.3 Al-base alloy containing 18-35% Al, 3-15% Cr, 0.2-0.5% B and/or C, and altogether 0-8% of the following alloying additives: Mo, Nb, Zr, Y and/or V, as well as iron as dominant remainder. In accordance with the invention additives are added to the melt of a known alloy, from which dispersed crystallites, dispersoids, are formed which thanks to good wettability become upon solidification, embedded in the monocrystalline phase. From the solid alloy, through hot rolling at a temperature between 650.degree. and 1000.degree. C., a fine grain structure may be generated.

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Winterthur, Switzerland

Emad Batawi