Abstract: A method for improving the performance and/or stability of non-precious metal catalysts in fuel cells and other electrochemical devices. Improved membrane electrode assemblies (MEAs) and fuel cells containing the same are provided. Such MEAs include a catalyst layer made up of at least two sub-layers containing ionomers of differing equivalent weights. The sub-layers may optionally contain mixtures of ionomers. Also provided are methods of making and using the described devices.

Abstract: A membrane electrode assembly comprises a polymer electrolyte interposed between an anode electrode and a cathode electrode, the anode electrode comprising an anode catalyst layer adjacent at least a portion of a first major surface of the polymer electrolyte, the cathode electrode comprising a cathode catalyst layer adjacent at least a portion of a second major surface of the polymer electrolyte; at least one of the anode and cathode catalyst layers comprising: a first catalyst composition comprising a noble metal; and a second composition comprising a metal oxide; wherein the second composition has been treated with a fluoro-phosphonic acid compound.

Abstract: A membrane electrode assembly comprises an anode electrode comprising an anode gas diffusion layer and an anode catalyst layer; a cathode electrode comprising a cathode gas diffusion layer and a cathode catalyst layer; and a polymer electrolyte membrane interposed between the anode catalyst layer and the cathode catalyst layer; wherein the cathode catalyst layer comprises: a first cathode catalyst sublayer adjacent the polymer electrolyte membrane, the first cathode catalyst sublayer comprising a first catalyst supported on a first carbonaceous support and a second catalyst supported on a second carbonaceous support; and a second cathode catalyst sublayer adjacent the cathode gas diffusion layer, the second cathode catalyst sublayer comprising a third catalyst supported on a third carbonaceous support; wherein the first carbonaceous support is carbon black and the second and third carbonaceous supports are graphitized carbon.

Abstract: A membrane electrode assembly comprises an anode electrode comprising an anode gas diffusion layer and an anode catalyst layer; a cathode electrode comprising a cathode gas diffusion layer and a cathode catalyst layer; and a polymer electrolyte membrane interposed between the anode catalyst layer and the cathode catalyst layer; wherein the cathode catalyst layer comprises: a first cathode catalyst sublayer adjacent the polymer electrolyte membrane, the first cathode catalyst sublayer comprising a first catalyst supported on a first carbonaceous support and a second catalyst supported on a second carbonaceous support; and a second cathode catalyst sublayer adjacent the cathode gas diffusion layer, the second cathode catalyst sublayer comprising a third catalyst supported on a third carbonaceous support; wherein the first carbonaceous support is carbon black and the second and third carbonaceous supports are graphitized carbon.

Abstract: A catalyst layer (20) for a fuel cell and to a method suitable for producing the catalyst layer (20). The catalyst layer (20) includes a catalyst material (22) containing a catalytic material (24) and optionally porous carrier material (23) on which the catalytic material (24) is supported. The catalyst layer also includes mesoporous particles (21) made from hydrophobic material.

Abstract: The present invention is related to methods of making membrane electrode assembly components. The methods include transferring a catalyst layer to a polymer electrolyte membrane or a gas diffusion layer. Methods of making membrane electrode assemblies with these components are also disclosed.

Abstract: An anode catalyst layer for a fuel cell is presented having first and second catalyst compositions and a hydrophobic binder. The first catalyst composition includes a noble metal, other than Ru, on a corrosion-resistant support material; the second catalyst composition contains a single-phase solid solution of a metal oxide containing Ru. The through-plane concentration of ionomer in the catalyst layer decreases as a function of distance from the membrane interface. Gas diffusion electrodes, catalyst-coated membranes, MEAs and fuel cells having the foregoing anode catalyst layer are also described.

Abstract: An anode catalyst layer for a fuel cell is presented having first and second catalyst compositions and a hydrophobic binder. The first catalyst composition includes a noble metal, other than Ru, on a corrosion-resistant support material; the second catalyst composition contains a single-phase solid solution of a metal oxide containing Ru. The through-plane concentration of ionomer in the catalyst layer decreases as a function of distance from the membrane interface. Gas diffusion electrodes, catalyst-coated membranes, MEAs and fuel cells having the foregoing anode catalyst layer are also described.

Abstract: A significant problem in PEM fuel cell durability is in premature failure of the ion-exchange membrane and in particular by the degradation of the ion-exchange membrane by reactive hydrogen peroxide species. Such degradation can be reduced or eliminated by the presence of an additive in the anode, cathode or ion-exchange membrane. The additive may be a radical scavenger, a membrane cross-linker, a hydrogen peroxide decomposition catalyst and/or a hydrogen peroxide stabilizer. The presence of the additive in the membrane electrode assembly (MEA) may however result in reduced performance of the PEM fuel cell. Accordingly, it may be desirable to restrict the location of the additive to locations of increased susceptibility to membrane degradation such as the inlet and/or outlet regions of the MEA.

Abstract: A membrane electrode assembly (MEA) may include an electrochemically separating sublayer disposed between the proton exchange membrane and an anode substrate. The MEA may also include a poison-scrubbing catalyst disposed between the electrochemically separating sublayer and the anode substrate. An anode electrocatalyst disposed between the proton exchange membrane and the electrochemically separating sublayer and a cathode electrocatalyst disposed between the cathode substrate and the proton exchange membrane.

Abstract: An anode catalyst layer for a fuel cell is presented having first and second catalyst compositions and a hydrophobic binder. The first catalyst composition includes a noble metal, other than Ru, on a corrosion-resistant support material; the second catalyst composition contains a single-phase solid solution of a metal oxide containing Ru. The through-plane concentration of ionomer in the catalyst layer decreases as a function of distance from the membrane interface. Gas diffusion electrodes, catalyst-coated membranes, MEAs and fuel cells having the foregoing anode catalyst layer are also described.

Abstract: The present invention is related to methods of making membrane electrode assembly components. The methods include transferring a catalyst layer to a polymer electrolyte membrane or a gas diffusion layer. Methods of making membrane electrode assemblies with these components are also disclosed.

Abstract: A membrane electrode assembly may be made using a one-sided catalyst coated membrane (CCM) wherein only one catalyst layer, either the anode or the cathode, is coated directly on the ion-exchange membrane. In particular, a one-sided CCM may be used where it may not be practicable to coat both sides of the ion-exchange membrane with catalyst layers such as when PTFE is added to the anode catalyst layer to render it reversal tolerant.

Abstract: In a solid polymer fuel cell series, various circumstances can result in a fuel cell being driven into voltage reversal. For instance, cell voltage reversal can occur if that cell receives an inadequate supply of fuel. In order to pass current, reactions other than fuel oxidation can take place at the fuel cell anode, including water electrolysis and oxidation of anode components. The latter can result in significant degradation of the anode, particularly if the anode employs a carbon black supported catalyst. Such fuel cells can be made substantially more tolerant to cell reversal by using certain anodes employing both a higher catalyst loading or coverage on a corrosion-resistant support and by incorporating, in addition to the typical electrocatalyst for promoting fuel oxidation, certain unsupported catalyst compositions to promote the water electrolysis reaction.

Abstract: In preparing a fluid diffusion electrode, typical methods include applying a catalyst ink to a fluid diffusion layer, drying the catalyst ink and hot-pressing the coated fluid diffusion layer to produce a fluid diffusion electrode. In the present application, unexpected improvements in the smoothness of the resulting electrode have been observed by drying the catalyst ink during compaction. To assist with drying the catalyst layer, the compacting step may be performed at elevated temperatures. In some embodiments, a release sheet may be applied to the catalyst layer prior to compaction. In addition or alternatively, partial drying of the catalyst layer may occur prior to compaction.

Abstract: Corrosion at the cathode catalyst may be a serious problem compromising fuel cell lifetimes. However in providing for increased corrosion resistance, an expected trade-off may occur regarding fuel cell performance. TKK (Tanaka Kikenzoku Kogyo) has solved this problem by providing both increased corrosion resistance with no concomitant loss in performance with their catalysts TEC50EA10 and TEC50BA10. An alternative to the TKK catalysts is to use an admixture of platinum black and supported catalyst and in particular, an admixture comprising 30-40% by weight platinum black and 60-70% by weight supported catalyst.

Abstract: A significant problem in PEM fuel cell durability is in premature failure of the ion-exchange membrane and in particular by the degradation of the ion-exchange membrane by reactive hydrogen peroxide species. Such degradation can be reduced or eliminated by the presence of an additive in the anode, cathode or ion-exchange membrane. The additive may be a radical scavenger, a membrane cross-linker, a hydrogen peroxide decomposition catalyst and/or a hydrogen peroxide stabilizer. The presence of the additive in the membrane electrode assembly (MEA) may however result in reduced performance of the PEM fuel cell. Accordingly, it may be desirable to restrict the location of the additive to locations of increased susceptibility to membrane degradation such as the inlet and/or outlet regions of the MEA.

Abstract: A membrane electrode assembly may be made using a one-sided catalyst coated membrane (CCM) wherein only one catalyst layer, either the anode or the cathode, is coated directly on the ion-exchange membrane. In particular, a one-sided CCM may be used where it may not be practicable to coat both sides of the ion-exchange membrane with catalyst layers such as when PTFE is added to the anode catalyst layer to render it reversal tolerant.

Abstract: In a solid polymer fuel cell series, various circumstances can result in a fuel cell being driven into voltage reversal. For instance, cell voltage reversal can occur if that cell receives an inadequate supply of fuel. In order to pass current, reactions other than fuel oxidation can take place at the fuel cell anode, including water electrolysis and oxidation of anode components. The latter can result in significant degradation of the anode, particularly if the anode employs a carbon black supported catalyst. Such fuel cells can be made substantially more tolerant to cell reversal by using certain anodes employing both a higher catalyst loading or coverage on a corrosion-resistant support and by incorporating, in addition to the typical electrocatalyst for promoting fuel oxidation, certain unsupported catalyst compositions to promote the water electrolysis reaction.

Abstract: Performance in solid polymer electrolyte fuel cells can be improved by varying the characteristics of the ionomer used in the electrode of a membrane electrode assembly. For instance, increasing the ionomer to catalyst ratio can allow for improved performance under drier operating conditions (e.g., when less humidified reactants or higher operating temperatures are used) or when starting up in below freezing conditions.