An electrochemical cell includes a fuel electrode, an air electrode containing a perovskite type oxide as a main component, the perovskite type oxide being represented by a general formula ABO.sub.3 and containing La and Sr at the A site, and a solid electrolyte layer arranged between the fuel electrode and the air electrode. The air electrode includes a first portion and a second portion, the first portion being located on the most upstream side in a flow direction of an oxidant gas that flows through a surface of the air electrode, the second portion being located on the most downstream side in the flow direction. A first ratio of a La concentration to a Sr concentration detected at the first portion through Auger electron spectroscopy is at least 1.1 times a second ratio of a La concentration to a Sr concentration detected at the second portion through Auger electron spectroscopy.

A method for producing a catalyst-coated membrane includes: preparing and/or providing a first ink having a first ink composition, comprising substrated catalyst particles proton-conducting ionomer and dispersing agent, in which the fraction of the substrated catalyst particles remains behind the fraction of the proton-conducting ionomer; preparing and/or providing at least one second ink having a second ink composition, comprising the substrated catalyst particles, the proton-conducting ionomer and the dispersing agent, in which the fraction of the proton-conducting ionomer remains behind the fraction of the substrated catalyst particles, unwinding a weblike proton-conducting membrane material provided on a roll; applying at least one layer of the first ink with a first application tool onto at least one section of the membrane material; and applying at least one layer of the second ink with a second application tool onto an outermost layer of the first ink deposited onto the membrane material

Electrochemical cells, such as those present within flow batteries, can include at least one electrode with one face being more hydrophilic than is the other. Such electrodes can lessen the incidence of parasitic reactions by directing convective electrolyte circulation toward a separator in the electrochemical cell. Flow batteries containing the electrochemical cells can include: a first half-cell containing a first electrode with a first face and a second face that are directionally opposite one another, a second half-cell containing a second electrode with a first face and a second face that are directionally opposite one another, and a separator disposed between the first half-cell and the second half-cell. The first face of both the first and second electrodes is disposed adjacent to the separator. The first face of at least one of the first electrode and the second electrode is more hydrophilic than is the second face.

A gas diffusion electrode for a fuel cell which comprises a gas-permeable substrate that has functional groups is provided, said groups being capable of complexing cations, and catalytically active noble metal particles and/or atoms, said particles and/or atoms being bonded by the functional groups to a surface of a first flat side of the substrate and/or in a surface-proximal region of a first flat side of the substrate. The gas diffusion electrode according to the invention combines the functions of a gas diffusion layer and a catalytic layer in an integral component and is distinguished by a high long-term stability with respect to degradation phenomena of the catalyst.

Disclosed are an electrode including a porous substrate, a membrane-electrode assembly for a fuel cell including the same and a method of manufacturing the same. In the method of manufacturing the membrane-electrode assembly, the amount of a catalyst that is loaded depending on the position is applied in a gradational manner, thus efficiently using the catalyst, thereby reducing costs owing to the use of a decreased amount of the metal catalyst. Further, the membrane-electrode assembly includes the electrode including a porous substrate, thus making it easy to select hot-pressing conditions and increasing processing efficiency. The porous substrate is hydrophobic and the pore size in the electrode is not decreased compared to conventional electrodes, thus reducing flooding and generating various operation regions. The electrode including the porous substrate can minimize electrode loss, thus improving electrode durability.

A membrane electrode assembly includes an electrolyte membrane, and a pair of electrodes sandwiching the electrolyte membrane. The pair of electrodes each include a catalyst layer, and a gas diffusion layer disposed on the catalyst layer on an opposite side to the electrolyte membrane. At least one of the catalyst layers contains first catalyst particles, and second catalyst particles. The first catalyst particles are either platinum particles or platinum alloy particles, or both. The second catalyst particles are core-shell particles having a core part and a shell part, the core part formed of at least one selected from transition metals other than platinum, the shell part covering the core part and formed of at least one of platinum and a platinum alloy. In the catalyst layer, the second catalyst particles are present in a smaller percentage in an electrolyte membrane side than they are in a gas diffusion layer side.

A gas diffusion electrode for a fuel cell which comprises a gas-permeable substrate that has functional groups is provided, said groups being capable of complexing cations, and catalytically active noble metal particles and/or atoms, said particles and/or atoms being bonded by the functional groups to a surface of a first flat side of the substrate and/or in a surface-proximal region of a first flat side of the substrate. The gas diffusion electrode according to the invention combines the functions of a gas diffusion layer and a catalytic layer in an integral component and is distinguished by a high long-term stability with respect to degradation phenomena of the catalyst.

The invention relates to an electrode for an electrochemical cell, wherein an electrode is flatly applied onto a surface of a solid oxide electrolyte, and a cathode is flatly applied onto the solid oxide electrolyte surface opposite the electrode. The base material of the electrode is a composite whose catalytically active metal component contains a nickel phase which is made of NiO as part of the electrode starting material by reducing the NiO in a hydrogen-containing atmosphere. The ceramic component is made with a doped cerium oxide and a spinel made of at least one transition metal selected from Ni, Mn, Fe, and Cr.

A layered structure for a fuel cell comprises a carbon-based catalyst-free gas diffusion layer substrate and a carbon-based microporous layer, which is joined to the gas diffusion layer substrate and comprises a plurality of carbon carriers or carbon fibers embedded into an ion-conducting polymer binder mixture. The polymer binder mixture comprises a sulfur-free binding polymer and a sulfonated polymer, and a fraction of the binding polymer at or near a surface of the microporous layer facing away from the gas diffusion layer substrate is less than or equal to a fraction of the sulfonated polymer. A method for producing a layered structure of this type is also provided.

A unit cell of a fuel cell may include: a membrane-electrode assembly including a proton exchange membrane, an anode electrode fastened to a first face of the proton exchange membrane, a first flow guide plate positioned facing the anode electrode and including at least one flow channel having a fuel inlet zone, a median flow zone and a fuel outlet zone. The anode electrode may have, at the fuel outlet zone, a tolerance to carbon monoxide pollution greater than its average tolerance to carbon monoxide pollution at the median flow zone and at the fuel inlet zone.