Abstract: Components that include catalyst layers used in membrane electrode assemblies (MEAs), and methods of making such components are described. The catalyst layers yield more uniform current distributions across the active area of the MEA during operation. The catalyst layers may have a uniform catalyst activity profile of a less active catalyst to achieve more uniform current density over the MEA active area. The catalyst layers may have a variable activity profile, such as an activity profile with a varying slope, to compensate for the inherent nonlinearities of catalyst utilization during operation of an electrochemical fuel cell. Desired variable catalyst activity profiles may be achieved, for example, by varying the catalyst loading across the MEA from inlet to outlet ports or by varying the surface area of the catalyst loading or by varying the surface area of the catalyst support elements.

Abstract: Processes for forming films comprising multiple layers of nanostructured support elements are described. A first layer of nanostructured support elements is formed by depositing a base material on a substrate and annealing. Further growth of the first layer of nanostructures is then inhibited. Additional layers of nanostructured support elements may be grown on the first layer of nanostructures through additional deposition and annealing steps. The multilayer films provide increased surface area and are particularly useful in devices where catalyst activity is related to the surface area available to support catalyst particles.

Abstract: A fuel cell cathode catalyst is provided comprising nanostructured elements comprising microstructured support whiskers bearing nanoscopic catalyst particles; wherein the catalyst comprises platinum and manganese and at least one other metal selected from the group consisting of Group VIb metals, Group VIIb metals and Group VIIIb metals other than platinum and manganese; wherein the volume ratio of platinum to the sum of all other metals in the catalyst is between about 1 and about 4, more typically between 1 and 4, more typically between about 2.5 and about 3.5, more typically between 2.5 and 3.5, and most typically about 3, and wherein the Mn content is equal to or greater than about 5 micrograms/cm2 areal density. Typically, the volume ratio of manganese to the at least one other metal is between 10:90 and 90:10. In one embodiment, the volume ratio of platinum to manganese to the at least one other metal is about 6:1:1. Typically, the at least one other metal is Ni or Co.

Abstract: A method is provided for making a supported catalyst comprising nanostructured elements which comprise microstructured support whiskers bearing nanoscopic catalyst particles, where the method comprises the step of depositing a catalyst material comprising at least three metallic elements on microstructured support whiskers from a single target comprising at least three metallic elements. Typically, at least one of said metallic elements is Pt. In addition, one or more of said metallic elements may be Mn, Ni or Co. Other metallic elements or other transition metal elements may be included. In addition, the present invention provides a supported catalyst comprising nanostructured elements which comprise microstructured support whiskers bearing nanoscopic catalyst particles made according to the method of the present invention. Further, the present invention provides fuel cell membrane electrode assembly comprising the supported catalyst according to the present invention.

Abstract: Processes for extending the length of nanostructured support elements of thin film layers are described. The processes involve the initial formation nanostructured support elements during a first annealing step. A coating of material is deposited on the nanostructured support elements. During a second annealing step the initially formed nanostructured support elements longitudinally extend. Longer nanostructured support elements provide increased surface area for supporting catalyst material, thus allowing higher catalyst loading across the layer. Layers having extended nanostructured support elements are particularly useful for electrochemical devices such as fuel cells where catalyst activity is related to the surface area available to support the catalyst.

Abstract: A membrane electrode subassembly includes an ion conducting membrane and a microporous layer having microtextured surfaces. Complementary features of the microtextured surfaces may be formed as grooves, ridges, pyramids or other shapes. Features of the microtextured surface of the ion conducting membrane engage features of the microporous layer. The engagement of the features of the microtextured surfaces may involve an interlocking fit, a tongue and groove fit, or another type of engagement. A thin catalyst layer is disposed between the microtextured surfaces. The microtextured surfaces increase the surface area at the catalyst layer interfaces.

Abstract: A method and apparatus is provided for recovering platinum metal from a catalyst-coated membrane comprising nanostructured elements by exposure to an oxidizing acidic solution. The method may additionally include, the subsequent step of precipitating a platinum salt from the oxidizing acidic solution. The method may additionally include the subsequent step of calcining the platinum salt.

Abstract: A method and apparatus is provided for recovering platinum metal from a fuel cell stack without disassembly, burning or electrolysis by introducing an oxidizing acidic solution to at least one of the ports of the stack. The method may additionally include the subsequent step of precipitating a platinum salt from the oxidizing acidic solution.

Abstract: A flexible flow field separator includes a substrate layer formed of a flexible material and having first and second surfaces. A structured flow field pattern is defined on the first surface of the substrate layer. The structured flow field pattern defines one or more fluid channels. The separator includes a first layer formed of one or more metals and disposed on the first surface of the substrate layer. The first layer is formed of an electrically conductive material. The separator further includes a second layer disposed on the second surface of the substrate layer. The second layer is formed of a flexible electrically conductive material. The first layer contacts the second layer at one or more locations to define an electrical connection between the first and second layers.

Abstract: A fuel cell sub-assembly includes first and second flow field plates each comprising several fastener apertures defined at a number of fastening locations. A membrane electrode assembly is situated between the first and second flow field plates and includes several fastener apertures defined at a number of fastening locations, the respective fastener apertures aligned to define fastening holes. A form-in-place fastener formed of an elastomeric material is disposed in each of the fastening holes. The elastomeric material facilitates volumetric displacement of the form-in-place fasteners in response to placing the fuel cell sub-assembly in compression.

Abstract: A cooling apparatus for a fuel cell assembly includes a heat transfer fluid and at least one fluid flow field plate configured to facilitate essentially passive, two-phase cooling for an membrane electrode assembly (MEA) as the MEA is subject to changes in heat flux to the heat transfer fluid from about 0 W/cm2 to about 1.5 W/cm2. The flow field plate includes fluid flow channels that have a channel depth, a channel spacing, a channel length, and a channel width, which are dimensioned to promote nucleated boiling of the heat transfer fluid below a critical heat flux and to prevent dryout as the heat transfer fluid passes along the length of the channels. The channels may include coatings and/or features, such as microporous or nanostructured coatings, that extend the critical heat flux and preclude dryout at the distal sections of the fluid flow channels.

Abstract: A fuel cell cathode catalyst is provided which comprises nanostructured elements comprising microstructured support whiskers bearing nanoscopic catalyst particles. The nanoscopic catalyst particles are made by the alternating application of first and second layers, the first layer comprising platinum and the second layer being an alloy or intimate mixture of iron and a second metal selected from the group consisting of Group VIb metals, Group VIIb metals and Group VIIIb metals other than platinum and iron, where the atomic ratio of iron to the second metal in the second layer is between 0 and 10, where the planar equivalent thickness ratio of the first layer to the second layer is between 0.3 and 5, and wherein the average bilayer planar equivalent thickness of the first and second layers is less than 100 ?.