Additives for fuel cell layers

Abstract

Fuel cell or fuel cell component including: a polyelectrolyte membrane containing an ionomer and an additive, wherein the additive contains at least one of PtO2, CoO or Co2O3, and, wherein the membrane comprises a first layer and a second layer above the first layer and a third layer below the first layer, wherein the first layer defines a central portion which is free of the additive, and wherein the second and third layers contain the additive.

Description

TECHNICAL AREA

[0001] The technical field to which the description of the exemplary embodiments generally refers includes fuel cells and fuel cell components comprising an ionomer layer, a membrane, a catalyst and a substrate, as well as methods for manufacturing and using the same. BACKGROUND

[0002] Fuel cells using solid polyelectrolyte membranes and electrodes are well-known. Experts are continuously working on improvements and alternatives for existing fuel cells, fuel cell components, and methods for their manufacture and use.

[0003] DE 697 17 674 T2 discloses a microporous membrane, wherein a metal oxide can cover the inner surface of the membrane's pores. US 2005 / 0136308 A1 discloses an ion exchange membrane for a fuel cell. An additive can be dispersed in the membrane or applied as a separate layer to its surface. US 2004 / 0043283 A1 discloses a membrane electrode assembly comprising an anode, a cathode, and a proton exchange membrane. The membrane electrode assembly includes a peroxide decomposition catalyst, which can be placed at one or more locations in the anode, cathode, or membrane, as well as in a layer between the anode and membrane, or between the cathode and membrane. DE 101 30 828 A1 discloses a fuel cell comprising at least one additive that prevents the formation of peroxides or decomposes them. US patent 2006 / 0046120 A1 discloses a fuel cell with an ionomer membrane and a component that can neutralize peroxide.This component can be a metal oxide, such as cerium oxide particles with micrometer or nanometer dimensions. DE 694 25 196 T2 discloses an electrochemical cell containing a polymeric solid electrolyte composition. This composition contains particles or fibers of at least one metal oxide for moisture control. JP H 10-55807 A describes fuel cell electrodes containing a catalyst, a cation exchange resin, and vanadium oxide or a cerium oxide-zirconium oxide complex as a co-catalyst. SUMMARY OF EXAMPLE FORMS OF EXECUTION

[0004] A fuel cell or fuel cell component comprises a polyelectrolyte membrane containing an ionomer and an additive, wherein the additive contains at least one of PtO2, CoO or Co2O3, and wherein the membrane comprises a first layer and a second layer above the first layer and a third layer below the first layer, wherein the first layer defines a central portion which is free of the additive, and wherein the second and third layers contain the additive.

[0005] Other exemplary embodiments of the invention will become apparent from the following brief description of the drawings, from the detailed description of exemplary embodiments, and from the accompanying patent claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The exemplary embodiments of the present invention will be more fully understood from the detailed description and the accompanying drawings, wherein: Fig. Figure 1 illustrates a fuel cell component according to an embodiment of the present invention. Fig. 2 illustrates a fuel cell component according to another embodiment of the present invention. Fig. 3 represents a fuel cell component according to another embodiment of the present invention. Fig. 4 illustrates a fuel cell component according to another embodiment of the invention. Fig. 5 represents a fuel cell component according to another embodiment of the present invention. DETAILED DESCRIPTION OF EXAMPLE EXECUTIONS

[0007] The following description of the following embodiment(s) is merely exemplary and is in no way intended to limit the claimed invention, its application or uses.

[0008] Now to the Fig. 1. Referring to the above, one embodiment of the present invention comprises a fuel cell substrate 10 containing an ionomer and an additive. The substrate 10 can be a membrane or an electrode. In various embodiments of the present invention, the additive improves cell performance, membrane lifetime, and / or proton conductance. In one embodiment of the present invention, the additive comprises an oxide of at least one of Ce, Mn, V, Pt, Ru, Zr, Ni, Cr, W, Co, Mo, or Sn, or derivatives thereof. In a further embodiment of the present invention, the additive is a metal oxide, including, but not limited to, MnO2, CeO2, PtO2, RuO2, VO, VO2, V2O3, V2O5, CeO2, CoO, Co2O3, NiO2, CrO2, WO3, SnO2, MoO3, MoO2, Mn2O3 and / or derivatives thereof, including, but not limited to, tertiary and / or quaternary compounds. In one embodiment, the additive comprises nanoparticles of cerium(IV) oxide (CeO2), CeZrO4, or Ce1-x Zr x O2, wherein x is less than 1. In another embodiment of the present invention, the additive comprises a mixture of metal oxides, including, but not limited to, CeO2 and MnO2 (preferred), CeO2 and CoO; CeO2 and Co2O3; CeO2 and VO; CeO2 and VO2; CeO2 and V2O3; CeO2 and V2O5; CeO2, NiO2, or CrO2 in a mixture with at least one of CeO2, MoO3, MoO2, MnO2, Mn2O3, RuO2, WO3, PtO2, or SnO2. In another embodiment of the present invention, the additive may contain nanoparticles, that is, particles with at least one dimension smaller than 200 nm. It has been found that the use of nanoparticles improves the performance of membrane assemblies compared with assemblies using macroparticles.

[0009] The ionomer can be a polymer macromolecule, some of whose constituent units have ionizable or ionic groups, or both. In one embodiment of the present invention, the ionomer comprises polymer molecules with carbon-fluorine backbone chains and perfluorine side chains containing sulfonic acid groups (also known as perfluorosulfonic acid polymers). Such ionomers are marketed by E.L. DuPont de Nemours & Company under the trade name NAFION. ®available. Other such ionomers are available from Asahi Glass & Asahi Chemical Company. In alternative embodiments, the ionomer may contain perfluorinated cation exchange polymers, hydrocarbon-based cation exchange ionomers, and anion exchange ionomers. In other alternative embodiments, the ionomer comprises sulfonated hydrocarbon polymers, including aromatic and non-aromatic sulfonic acid polymers, including sulfonated polysulfones, sulfonated polyetheretherketones, sulfonated polyaryleneetherketones, sulfonated polyarylenethioetherketones, sulfonated polyaryleneethersulfones, sulfonated polyarylenethioethersulfones, sulfonated polybenzimidazoles, sulfonated polyimides, sulfonated polyphenylenes, or sulfonated polyphenylene sulfides.

[0010] In various illustrative embodiments of the present invention, the additive can be present in an amount of at least 0.1 wt%, approximately 1 to approximately 20 wt%, approximately 5 to approximately 15 wt%, or approximately 8 to approximately 12 wt% of the dried ionomer. The additive can be present in larger amounts; however, excessive oxide loading in the membrane can lead to brittle membranes that are more easily separated. The additive can be mixed with the ionomer in wet form, including water and alcohol. In the wet phase of the mixture, the water can be present in approximately 40 to approximately 60 wt% and the alcohol in approximately 40 to approximately 60 wt%. In some embodiments of the present invention, the additive is introduced into the mixture with a metal oxide purity in the range of approximately 90 to 100 percent or between approximately 99.99 and 100 percent.For example, the metal oxide for an additive containing MnO2 with a metal oxide purity in the range of 90 to 100 percent purity contains 90 to 100 wt% MnO2 and 0 to 10 wt% impurities, such as impurities typically found in Mn ore or during the production of MnO2. In various embodiments of the present invention, the substrate containing the ionomer and additive can have a thickness, in the dried state, of less than 100 micrometers, between approximately 5 and 50 micrometers, between approximately 10 and 40 micrometers, or thicknesses in between. When MnO2 with particle dimensions of less than 5 micrometers and with a purity of 85 percent was added to a 20 wt% Nafion 1000 (DE 2020) dispersion in 1-propanol-water (available from EI DuPont de Nemours and Company), the ionomer aggregated after 1 hour and the dispersion could no longer be coated.Therefore, a dispersion of 85 wt% MnO2 in Nafion 1000 (at 10 wt% MnO2 loading per ionomer solid) had to be coated into films within 1 hour. This does not occur with high-purity MnO2. Now referring to the... Fig. 2. In another embodiment of the present invention, the substrate 10 can comprise a first layer 12, a second layer 14 located above the first layer 12, and a third layer 16 located below the first layer 12. In one embodiment of the present invention, the first layer 12 contains an ionomer but without any metal oxide. The second layer 14 and the third layer 16 each contain an ionomer and an additive, such as a metal oxide. Each of the first layer 12, the second layer 14, and the third layer 16 can have a thickness, in the dried state, in a range between 5 and 50 micrometers, between 5 and 35 micrometers, between 10 and 35 micrometers, or thicknesses in between.A cathode catalyst layer can be located above the first layer 12 and an anode catalyst layer can be located below the third layer 16, wherein both the second and the third layers 14 and 16 contain an additive which may be the same or different from each other.

[0011] Now referring to the Fig. 3. According to another embodiment of the present invention, a solid polyelectrolyte membrane 102 is provided, which is essentially free of metal oxides. A first catalyst layer 18 is provided above the membrane, and a second catalyst layer 18' is provided below the membrane 102. At least one of the first catalyst layer 18 or the second catalyst layer 18' contains an additive, such as a metal oxide, which is present in an amount of at least one percent by weight of the dried ionomer in the catalyst layer 18 or 18'. The additives in the layers 18 and 18' can be the same or different from each other.

[0012] Now referring to the Fig. 4. In one embodiment of the present invention, a substrate 10 may be in the form of a two-layer membrane comprising a first section 12 and a second section 14. A first catalyst layer (for example, an anode) may be located above the membrane 10, and a second catalyst layer 18' may be located below the membrane. The first section 12 may contain a first additive, such as a first metal oxide, and the second section 14 may contain a second additive, such as a second metal oxide. The first additive may contain a metal oxide that is different from the metal oxide of the second additive. For example, the first section 12 (adjacent to the cathode 18') may contain MnO₂, and the second section 14 (adjacent to the anode 18) may contain CeO₂.In another embodiment, at least one of the catalyst layers 18, 18' can contain the first additive and at least one portion of the membrane 10 can contain the second additive, wherein the membrane 10 can be made of a single layer or of several layers. For example, the anode layer 18 can contain CeO2 and the first portion 12 (adjacent to the cathode) of the membrane 10 can contain MnO2, wherein the second portion 14 of the membrane 10 and the cathode 18' may or may not contain a metal oxide additive.

[0013] Now referring to the Fig.Figure 5 of the present invention comprises a product containing a fuel cell substrate 10, which functions as a proton exchange membrane. The substrate 10 comprises a first layer 12 containing an ionomer without a metal oxide. A second layer 14 is provided above the first layer 12, and a third layer 16 is provided below the first layer 12. Each of the second layer 14 and the third layer 16 contains an ionomer and an additive, such as a metal oxide or a mixture of metal oxides. As such, the substrate 10, in this case a polyelectrolyte membrane, contains a central portion that is free of the metal oxide additive. A first catalyst layer 18 is provided above the second layer 14 of the substrate 10.A first gas diffusion media substrate 22 can be provided above the first catalyst layer 18, and optionally a microporous layer 20 can be inserted between the diffusion media substrate 22 and the first catalyst layer 18. The diffusion media substrate 22 can contain a carbon paper substrate, but is not limited to this. The microporous layer 20 can be coated on the diffusion media substrate 22 with a mixture of carbon and fluoropolymer, such as FEP, PVDF, HFP, PTFE, etc. The first catalyst layer 18 preferably contains a group of finely dispersed catalyst support particles, such as carbon, which carry finely dispersed catalyst particles as well as an ion-conducting material that is mixed with the support and the catalyst particles. The ion-conducting material in the first catalyst layer 18 can be an ionomer, such as a perfluorinated sulfonic acid polymer.Catalyst materials may include, but are not limited to, metals such as platinum, palladium, and mixtures of metals such as platinum and molybdenum, platinum and cobalt, platinum and ruthenium, platinum and nickel, and platinum and tin, or platinum-transition metal alloys. A first bipolar plate 24 may be provided with gas flow field channels 28 and connection surfaces 26 formed on one surface, and with cooling channels 30 formed on another surface. Likewise, a second catalyst layer 18', a second microporous layer 20', a second gas diffusion media substrate 22', and a second bipolar plate 24' may be provided on opposite sides of the fuel cell substrate 10 in a similar manner to form a fuel cell assembly 50.

[0014] In one embodiment of the present invention, a slurry containing an ionomer, an additive, and a solvent is prepared. The solvent may contain at least one of 1-propanol, ethanol, 1-butanol, methanol, or water. The slurry can be milled, for example, using glass beads, and subsequently filtered, for example, using a sieve with openings of less than 90 micrometers. The filtered slurry can be cast and dried as a single layer, or it can be cast and dried as multiple layers to form a multilayer membrane in one embodiment of the present invention, wherein at least one of the layers contains the additive.

[0015] Methods other than ball milling can be used to form the metal oxide ionomer dispersions. Other known wet mixing and melting processes can be employed, including stirred ball mills, homogenizers, mixers, polytron heads, melt extruders, Banbury roller mills, and others, such as blending plants. Illustrative examples for membrane production are also described in Examples 8 and 9 below.

[0016] A fuel cell test for membrane electrode setups was conducted using a catalyst-coated diffusion medium, a NAFION (N1000) membrane, and an additive containing an oxide of Mo. 6+ , V 5+ , V 3+The membrane assemblies, containing Cr / Zr alone or mixed with cerium(IV) oxide, were tested and found to function under all conditions. The conditions under which these membranes were tested with catalyst-coated diffusion media were as follows: Membranes were tested in fuel cells, and performance was summarized in polarization curves, plotting cell voltage (in volts) against current density (in A / cm²). 2) was applied under the following conditions: 150% relative humidity (RH) outside: 2 / 2 (A / C) stochastic; 100 / 50% (A / C) inlet RH; 80 °C; 170 kPa pressure; 110% relative humidity (RH) outside: 2 / 2 (A / C) stochastic; 100 / 50% (A / C) inlet RH; 80 °C; 50 kPa pressure; 85% relative humidity (RH) outside: 3 / 3 (A / C) stochastic; 50 / 50% (A / C) inlet RH; 80 °C; 75 kPa pressure; 80% relative humidity (RH) outside: 2 / 2 (A / C) stochastic; 35 / 35% (A / C) inlet RH; 80 °C; 50 kPa pressure; 63% relative humidity (RH) outside; 3 / 3(A / C) stochastic; 32 / 32% (A / C) inlet RH; 80°C; 50 kPa pressure; where (A / C) denotes anode / cathode. Polarization curves were obtained where the current density was up to 1.2 A / cm². 2 When the membranes ran at a reasonable voltage (usually more than 0.4 V), they were described as "running under all conditions".

[0017] When the terms “above”, “overlay”, “lying above” or “below”, “lying below”, “underlying” are used here with reference to the relative position of a component or layer in relation to a second component or layer, this is intended to mean that the first component or layer is in direct contact with the second component or layer, or that additional layers or components may be located between the first component or layer and the second component or layer. EXAMPLES

[0018] COMPARISON EXAMPLE 1. A Nafion was used as a control sample. ® -Solution DE2020 with 20 wt% polymer solids Nafion ®PFSA polymer at 1000 equivalent weight in 40 wt% aqueous 1-propanol (available from E.I. DuPont de Nemours, Co.) was poured onto a glass plate using a Bird applicator at a distance of 76.2 µm. The coated glass plate was then oven-dried at 80 °C for 30 minutes. A second coating was applied over the first film using the Bird applicator at a distance of 76.2 µm, and the polymer-coated glass plate was heated at 120 °C for 16 hours. After cooling to 25 °C, the coated glass plate was immersed in a deionized water bath until the polymer film detached from the glass. The polymer film was allowed to air-dry on a paper towel, and the resulting dry film had a thickness of 25 micrometers. The polymer film was cut into squares measuring 101.6 mm by 101.6 mm and placed in a fuel cell (50 cm²). 2Hardware) with catalyst-coated diffusion media were assembled. Performance was measured under dry, wet, and intermediate conditions. A lifetime test was performed using an accelerated 5-minute wet, 5-minute dry protocol, and the membrane lifetime was 392 hours before a 40 cm 3 A cross-leak was detected. Fluoride release during the test was 10 -5 g F- per cm 2 Membrane area per hour. A platinum line formed on the cathode side, where the platinum had detached from the catalyst layer and diffused into the membrane, where the platinum ions were then presumably reduced by diffusing hydrogen gas from the anode.

[0019] EXAMPLE 2, NAFION MEMBRANE WITH MnO2. The purity of the MnO2 supplied by Aldrich was 99.99+%. When samples were produced with a MnO2 purity level of only 85%, the fuel cell performance suffered compared to the control membrane made of Nafion. ® 1000 on its own, without additives considerable. Pure MnO2 solid (0.5 g, Aldrich) was used to make a Nafion. ® -Solution DE2020 with 20 wt.% polymer solids Nafion ® PFSA polymer, which was 1,000 equivalent weight ionomer in 40 wt% aqueous 1-propanol (available from EI DuPont de Nemours, Co.), to a 118.29 cm 3 A 4-ounce glass bottle was added, followed by the addition of grinding medium containing 5 mm glass beads (15 g, Fisher Scientific). The container lid was locked, and the container was roller-milled for a minimum of 16 hours. The metal oxide was then treated with 10 wt% solids based on dry Nafion. ®admitted and was associated with Nafion ® 1000 (DE2020) PFSA ionomer dispersion in aqueous 1-propanol using glass beads as the milling medium was roller-milled for at least 16 h to form a dispersion. The mixture was then filtered through an 85 µm PTFE sieve and cast into films in two ways: (1) as a single layer 25 to 30 µm thick and (2) as a sandwich structure layered in 3 layers consisting of [10 µm Nafion]. ® PFSA] / [10 µm PFSA with dispersed metal oxide] / [10 µm Nafion ®[PFSA]. Individual layers were applied to a glass plate using a Bird applicator with a 76.2 µm spacing and a masking strip spacer (85 µm) and oven-dried for 30 minutes at 30 °C. The film was then floated off the glass and used as a fuel cell membrane. When successive coatings were applied, a Bird applicator with a 76.2 µm spacing was used, with oven drying for 30 minutes at 80 °C between each successive coating. The first coating was applied using a Nafion solution alone. The second coating was applied using a Nafion ® A dispersion with metal oxide (MnO2) was carried out and applied to the first film using a Bird applicator at a distance of 76.2 µm. The polymer-coated glass plate was then heated at 80 °C for 30 minutes. After a third layer of Nafion ®The polymer-coated glass plate was heated at 120 °C for 16 hours after the solution was applied using a Bird applicator at a distance of 76.2 µm. After cooling to 25 °C, the coated glass plate was immersed in a deionized water bath until the polymer film detached from the glass. The polymer film was then allowed to air dry on a paper towel, resulting in a dry film 30 micrometers thick. The polymer film was cut into 101.6 mm x 101.6 mm squares and used to construct a fuel cell (50 cm²). 2The active area was assembled with a catalyst-coated diffusion medium. Performance was measured under dry, wet, and intermediate conditions. A lifetime test was performed using an accelerated 5-minute wet, 5-minute dry protocol, and the lifetime of the single-layer MnO2-coated membrane was 1070 hours before a small pinhole cross-leak was detected. Fluoride release during the test was 10 -7 g F- per cm 2 Membrane area per hour. No membrane thinning or platinum line was detected on this membrane. The membrane, constructed as a sandwich structure, failed shortly after penetration, and this arrangement did not improve membrane lifetime. Consequently, the single-layer structure is assumed to be superior to the multi-layer sandwich structure.

[0020] COMPARISON EXAMPLE 2. NAFION MEMBRANE WITH MnO2 WITH 85 wt% PURITY: A dispersion of 10 wt% MnO2 (85 wt% purity with a particle size of less than 5 micrometers available from Aldrich) in Nafion 1000 dispersion (DE 2020) was prepared by adding MnO2 (0.33 grams) to Nafion 1000 dispersion (15 g with 20 wt% resin solids) and glass beads (25 grams) in a 40 ml glass vessel sealed with a Teflon screw cap. This dispersion was then roller-milled for one hour, filtered through a Teflon filter fabric with an 85-micrometer pore size, and poured as a film onto floated glass (0.2032 m x 0.2032 m x 6.35 mm) using a Bird applicator rod with a coating distance of 0.277 mm. After heating for 16 hours at 125 °C, the film was floated off with deionized water and then air-dried.A 101.6 mm x 101.6 mm piece of the film (thickness: 25 micrometers) was installed in a fuel cell with a catalyst-coated diffusion medium, and this fuel cell failed to operate. When roller milling for more than one hour was performed to form the MnO2-Nafion 1000 dispersion, the ionomer gelled, and the dispersion could not be coated into a film. Consequently, the 85% purity MnO2 was unsuitable as an additive for a Nafion 1000 membrane with a 10 wt% loading due to its poor performance, and in particular, it was unsuitable for a fuel cell membrane intended for competitive use in motor vehicles.

[0021] EXAMPLE 3, NAFION MEMBRANE WITH CeO2. Two types of metal oxides were used: cerium(IV) oxide nanoparticles and cerium(IV) oxide nanoparticles in water (Aldrich). The CeO2 nanoparticles were added at 10 wt% based on the resin solids to form a Nafion membrane. ®A solution was added, and a dispersion was prepared using glass bead milling media as in Example 2. The cerium(IV) dispersion was coated and dried as in Example 2. A lifetime test was performed using an accelerated 5-minute wet, 5-minute dry protocol, and this single-layer coated membrane with cerium(IV) nanoparticles showed no failures after more than 1,510 hours, and no cross-leakage was detected after this time. Furthermore, no membrane thinning or platinum line was detected with this membrane. Fluoride release during the test was 10 -7 g F- per cm 2 Membrane area per hour. The membrane, constructed as a sandwich structure, failed shortly after the breach, and this arrangement did not improve membrane lifespan. Consequently, the single-layer structure is assumed to be superior to the multi-layer sandwich structure.

[0022] EXAMPLE 4, A BID-LAYER NAFION MEMBRANE WITH CER(IV) OXIDE (CeO2) AND MnO2. A two-layer membrane structure was fabricated using a membrane produced by two coatings. The first coating, applied with a Bird applicator at a distance of 76.2 µm, was made with a Nafion ® -Dispersion, which contained cerium(IV) oxide nanoparticles prepared as in Example 3, was carried out and the second layer was applied to the first cerium(IV) oxide-containing layer using a Bird applicator with a 76.2 µm coating distance with a Nafion prepared as described in Example 2. ®A dispersion with MnO2 was produced. A lifetime test was performed under an accelerated 5-minute wet, 5-minute dry protocol, and this single-layer coated membrane with cerium(IV) oxide nanoparticles (on the anode side) showed no failures even after more than 1,680 hours, and no cross-leakage was detected after this period. Fluoride release during the test was 10 -7 g F- per cm 2 Membrane area per hour. This membrane showed better conductivity than the corresponding membranes produced as described in Examples 2 and 3.

[0023] EXAMPLE 5, NAFION MEMBRANE WITH PtO2. A single layer of Nafion ®The membrane was fabricated with dispersed PtO2 at a loading of 10 wt% based on the ionomer. This membrane exhibited better performance than the Nafion control, but a gas cross-leak occurred shortly after the membrane's lifespan. Consequently, the lifetime was not improved, although performance was enhanced, particularly under dry operating conditions. Reducing the loading from 10 wt% to 5 wt% PtO2 and then to 1 wt% PtO2 based on the ionomer resulted in both improved performance compared to the control and improved lifetime compared to the membrane with 10 wt% PtO2.

[0024] EXAMPLE 6, NAFION MEMBRANE WITH RuO2. A single layer of Nafion ®The membrane was fabricated with dispersed RuO2. The membrane showed improved performance compared to the Nafion control, but a gas cross-leak occurred shortly after the membrane's lifespan. Consequently, the lifetime was not improved, but performance was improved, particularly under dry operating conditions. Reducing the loading from 10 wt% to 5 wt% RuO2 and then to 1 wt% RuO2, based on the ionomer, resulted in both improved performance compared to the control and improved lifetime when compared to the membrane with 10 wt% RuO2.

[0025] EXAMPLE 7, NAFION MEMBRANE WITH OTHER METALLOXIDES AND MIXTURES OF METALLOXIDES. Nafion ® Membranes were coated with other metal oxides including vanadium oxides (in the III, IV and V oxidation states), Co 2+ / 3+ -Oxide (10 wt% solids), RuO2 (with 1 and 5 wt% based on polymer solids), PtO2 (with 1 wt% based on Nafion)® -solids), MoO2, Mo2O3 and mixtures of metal oxides. An improvement in membrane lifetime and membrane performance was observed, particularly under dry conditions. Interestingly, it was found that Co 2+ / 3+ -Oxide impaired performance when not mixed with cerium(IV) oxide nanoparticles, although in the latter case, performance was surprisingly improved. Vanadium oxides with vanadium in the 3+ and 5+ oxidation states significantly improved the membrane's dry performance, to such an extent that the dry performance surpassed the wet and intermediate moistened membrane performance. However, the lifetime improvements with vanadium oxides with Nafion were ®This alone did not improve performance. It was found that a membrane with cerium(IV) oxide on the anode and V2O3 on the cathode not only performed better under dry operating conditions, but also dramatically improved the membrane lifetime.

[0026] EXAMPLE 8 - CER(IV) OXIDE MEMBRANE PROCESSED BY EXTRUSION. Poly(tetrafluoroethylene perfluorosulfonyl fluoride) (DE-838WX film from E.I. DuPont de Nemours) is comminuted using a Waring mixer, and cerium(IV) oxide nanoparticles (Aldrich) are added at 10 wt% based on the polymer. The mixture is rapidly extruded between 148.89 and 204.44 °C (176.67 °C) using a Dynisco laboratory mixing extruder (model LME) equipped with a single-hole die. The strand is comminuted using a Waring mixer and then extruded under the same conditions, but with the extruder equipped with a wide-band slot die. The ribbon is then compressed between two rollers to produce a cerium(IV) oxide film. The film is then immersed for 16 hours in 20 wt% aqueous potassium hydroxide in dimethyl sulfoxide. The film is then extensively washed with water and immersed for 16 hours in 2 normal sulfuric acid solutions.The film is then washed with water until the pH of the water washes is close to 7. In this way, cerium(IV) oxide is melt-mixed to form a perfluorosulfonic acid polymer membrane suitable for fuel cells.

[0027] EXAMPLE 9 - CER(IV) OXIDE MEMBRANE PROCESSED BY PRESSING. A solution-cast cerium(IV) oxide membrane is prepared as described in Example 2. This membrane is immersed in salt water, and 50 wt% sodium hydroxide is added dropwise until the pH is close to 10. The film is then extensively washed with water and air-dried. The film is then sandwiched between 127 mm x 127 mm steel plates coated with a layer of Gylon. ®To distribute the pressure, the film is pressed with a 0.127 mm Teflon release sheet at a pressure between 907.18 and 2721.55 kilograms and at 204.44 °C for 4 to 20 minutes. The film is allowed to cool to room temperature and is then immersed in two solutions of ordinary sulfuric acid for 16 hours. The film is then extensively washed with water until the pH of the water washes is close to 7. In this way, perfluorosulfonic acid in its salt form is processed with cerium(IV) oxide by compression molding to produce a membrane suitable for fuel cells.

Claims

[1] Fuel cell or fuel cell component comprising: a polyelectrolyte membrane containing an ionomer and an additive, wherein the additive contains at least one of PtO2, CoO or Co2O3, and, wherein the membrane comprises a first layer and a second layer above the first layer and a third layer below the first layer, wherein the first layer defines a central portion which is free of the additive, and wherein the second and third layers contain the additive. [2] Fuel cell or fuel cell component according to claim 1, wherein the additive consists of nanoparticles. [3] Fuel cell or fuel cell component comprising: a polyelectrolyte membrane containing an ionomer and an additive, wherein the additive contains CeO2 and at least one of CoO, Co2O3, VO, VO2, V2O3 or V2O5. [4] Fuel cell or fuel cell component according to claim 3, wherein the membrane has a single layer. [5] Fuel cell or fuel cell component according to claim 3, wherein the membrane has a central section which is free of the additive. [6] Fuel cell or fuel cell component comprising: a polyelectrolyte membrane containing an ionomer and an additive mixture, which includes a first additive containing at least one of NiO2 or CrO2 and a second additive containing at least one of RuO2, WO3, PtO2 or SnO2, and, wherein the membrane comprises a first layer and a second layer above the first layer and a third layer below the first layer, wherein the first layer defines a central portion which is free of the additive and the second and third layers contain the additive. [7] Fuel cell or fuel cell component containing: a fuel cell electrode comprising a catalyst, an ionomer and an additive comprising CeO2 and at least one of CoO or Co2O3. [8] Fuel cell or fuel cell component comprising: a first layer comprising a first ionomer and an additive, wherein the additive comprises a metal oxide, the metal oxide having a metal oxide purity in the range of 90 to 100% purity, the metal oxide comprising an oxide of at least one of Ce, Mn, V, Pt, Ru, Zr, Ni, Cr, W, Co or Mo, and wherein the additive is present in an amount of at least 0.1% by weight of the ionomer, further comprising a second layer comprising a second ionomer, the second layer being arranged below the first layer, and the second layer being free of any metal or metal oxide. [9] Fuel cell or fuel cell component according to claim 8, wherein the metal oxide has a metal oxide purity in a range between 99.99 and 100 percent purity. [10] Fuel cell or fuel cell component according to claim 8, wherein the metal oxide contains at least one of MnO2, CeO2, PtO2, RuO2, VO, VO2, V2O3, V2O5, CeO2, CoO, Co2O3, NiO2, CrO2, WO3, SnO2, MoO3, MoO2, Mn2O3, CeO2 and CoO; CeO2 and Co2O3; CeO2 and VO; CeO2 and VO2; CeO2 and V2O3; CeO2 and V2O5; CeO2, NiO2 or CrO2 in a mixture with at least one of CeO2, MoO3, MoO2, Mn2O3, RuO2, WO3, PtO2 or SnO2 or derivatives thereof. [11] Fuel cell or fuel cell component according to claim 8, wherein the additive consists of nanoparticles. [12] Fuel cell or fuel cell component according to claim 8, wherein the additive contains nanoparticles comprising at least one of cerium(IV) oxide (CeO2), CeZrO4 or Ce 1-x Zr xO2, in which x is less than 1, is contained. [13] Fuel cell or fuel cell component according to claim 8, wherein the additive contains a mixture of metal oxides comprising: CeO2 and MnO2; CeO2 and CoO; CeO2 and Co2O3; CeO2 and VO; CeO2 and VO2; CeO2 and V2O3; CeO2 and V2O5; CeO2 in a mixture with at least one of MoO3, MoO2, Mn2O3. [14] Fuel cell or fuel cell component according to claim 13, wherein the additive consists of nanoparticles. [15] Fuel cell or fuel cell component according to claim 8, wherein the additive contains NiO2 and at least one of RuO2, WO3, PtO2 or SnO2. [16] Fuel cell or fuel cell component according to claim 8, wherein the additive contains CrO2 and at least one of RuO2, WO3, PtO2 or SnO2. [17] Fuel cell or fuel cell component according to claim 8, wherein the metal oxide is contained in an amount in the range between 0.1 and 5 weight percent of the first ionomer. [18] Fuel cell or fuel cell component according to claim 8, wherein the metal oxide is contained in an amount in a range between 8 and 12 weight percent of the first ionomer. [19] Fuel cell or fuel cell component according to claim 8, wherein the metal oxide consists of RuO2. [20] Fuel cell or fuel cell component according to claim 8, wherein the first ionomer contains molecules which have a carbon-fluorine backbone with perfluorine side chains containing sulfonic acid groups. [21] Fuel cell or fuel cell component according to claim 8, wherein the first ionomer contains a perfluorosulfonic acid polymer. [22] Fuel cell or fuel cell component according to claim 8, wherein the first ionomer contains at least one of an aromatic hydrocarbon or an aliphatic polymer. [23] Fuel cell or fuel cell component according to claim 8, wherein the first ionomer comprises a sulfonated polysulfone polyetheretherketone, sulfonated polyarylene etherketones, sulfonated polyarylene ethersulfones, sulfonated polyarylene thioetherketones, sulfonated polyarylene ethersulfones, sulfonated polybenzimidazoles, sulfonated polyimides, sulfonated polyphenylenes or sulfonated polyphenylene sulfide as randomly distributed polymers, block or multiblock polymers or as mixtures thereof. [24] Fuel cell or fuel cell component according to claim 8, wherein the first layer in a dried state has a thickness in a range between 5 and 100 micrometers. [25] Fuel cell or fuel cell component according to claim 8, wherein the first layer in the dried state has a thickness in a range between 5 and 50 micrometers. [26] Fuel cell or fuel cell component according to claim 25, wherein the first layer in the dried state has a thickness in a range between 5 and 30 micrometers. [27] Fuel cell or fuel cell component according to claim 26, wherein the first layer in the dried state has a thickness in a range between 5 and 12 micrometers. [28] Fuel cell or fuel cell component according to claim 8, further comprising a third layer which is arranged below the second layer, wherein the third layer has the same composition as the first layer. [29] Procedure encompassing: Forming a dispersion containing a first ionomer, an additive and at least one of an alcohol or water, Casting and drying the dispersion to form a dried first layer containing the first ionomer and the additive, wherein the additive comprises a metal oxide with a metal oxide purity in the range between 90 and 100 percent purity, wherein the metal oxide comprises an oxide of at least one of Ce, Mn, V, Pt, Ru, Zr, Ni, Cr, W, Co or Mo, and wherein the additive is present in an amount of at least one percent by weight of the dried first layer. Deposition of a second layer over the first layer, wherein the second layer contains a second ionomer and is free of a metal or metal oxide. [30] Method according to claim 29, wherein the dispersion contains water. [31] Method according to claim 29, wherein the alcohol contains at least one of ethanol, 1-propanol, 2-propanol or 1-butanol. [32] Method according to claim 29, wherein the first layer has a thickness in the range of 1 to 50 micrometers after drying. [33] Method according to claim 29, wherein the first layer has a thickness in a range between 5 and 35 micrometers. [34] Method according to claim 33, wherein the first layer has a thickness in a range between 8 and 12 micrometers. [35] The method of claim 29, further comprising grinding the dispersion prior to casting and drying. [36] Method according to claim 35, wherein the grinding further comprises the use of glass spheres as a grinding medium. [37] Method according to claim 29, wherein the additive contains a metal oxide with a purity in the range between 99 and 100 percent purity. [38] Method according to claim 29, wherein the additive contains a metal oxide with a purity in a range between 99.99 and 100 percent purity. [39] Method according to claim 29, wherein the casting comprises the deposition of the dispersion on a second layer. [40] The method of claim 38, further comprising forming the second layer, comprising forming a second dispersion containing a second ionomer, casting the second dispersion onto a third layer and drying the second dispersion. [41] The method of claim 38, further comprising forming a third layer over the first layer, wherein the third layer contains a third ionomer. [42] Method according to claim 39, wherein at least one of the first layer, the second layer or the third layer contains a perfluorosulfonic acid polymer. [43] Method according to claim 29, wherein at least one of the ionomers of the first layer, the second layer or the third layer contains at least one of a sulfonated, aromatic, aliphatic hydrocarbon polymer. [44] Method according to claim 29, wherein each of the first layer, the second layer and the third layer has a thickness in a range between 5 and 12 micrometers. [45] Method according to claim 29, wherein the metal oxide contains at least one of MnO2, CeO2, PtO2, RuO2, VO, VO2, V2O3, V2O5, CoO, Co2O3, NiO2, CrO2, WO3, SnO2, Mn2O3, MoO3, MoO2 or derivatives thereof. [46] Method according to claim 29, wherein the additive consists of nanoparticles. [47] Method according to claim 29, wherein the additive contains nanoparticles comprising at least one of cerium(IV) oxide (CeO2), CrZeO4 or Ce 1-x Zr x O2, in which x is less than 1, is contained. [48] ​​The method of claim 29, wherein the additive comprises a mixture of metal oxides comprising: CeO2 and MnO2; CeO2 and CoO; CeO2 and Co2O3; CeO2 and VO; CeO2 and VO2; CeO2 and V2O3; CeO2 and V2O5; CeO2 in a mixture with at least one of MoO3, MoO2, Mn2O3. [49] Method according to claim 29, wherein the additive contains NiO2 and at least one of RuO2, WO3, PtO2 or SnO2. [50] Method according to claim 29, wherein the additive contains CrO2 and at least one of RuO2, WO3, PtO2 or SnO2. [51] Fuel cell or fuel cell component comprising: a first layer component comprising a first ionomer and a first additive, wherein the first additive comprises a metal oxide which is an oxide of at least one of Ce, Mn, V, Pt, Ru, Zr, Ni, Cr, W, Co, Mo or Sn, and wherein the first additive is present in an amount of at least 0.1 percent by weight of the ionomer, a second layer component comprising a second ionomer and a second additive, wherein the second additive contains a metal oxide comprising an oxide of at least one of Ce, Mn, V, Pt, Ru, Zr, Ni, Cr, W, Co, Mo or Sn, and wherein the second additive is present in an amount of at least 0.1 percent by weight of the ionomer, and wherein the first additive contains a metal oxide different from the metal oxide of the second oxide. [52] Fuel cell or fuel cell component according to claim 51, wherein the first layer section further comprises a catalyst and catalyst support particles. [53] Fuel cell or fuel cell component according to claim 52, wherein the second layer component further comprises a catalyst and catalyst support particles. [54] Fuel cell or fuel cell component according to claim 51, wherein the second layer section is free and wherein the second layer section is part of an electrolyte membrane. [55] Fuel cell or fuel cell component according to claim 51, wherein the first additive consists of CeO2 and the second additive consists of MnO2. [56] Fuel cell or fuel cell component according to claim 51, wherein the first layer section and the second layer section form at least one section of an electrolyte membrane. [57] Fuel cell or fuel cell component according to claim 51, comprising a two-layer electrolyte membrane comprising the first layer segment and the second layer segment. [58] Fuel cell or fuel cell component according to claim 53, comprising a two-layer electrolyte membrane comprising the first layer segment and the second layer segment. [59] Fuel cell or fuel cell component according to claim 51, wherein the first additive and the second additive consist of nanoparticles. [60] Fuel cell or fuel cell component according to claim 51, wherein each of the first additive and the second additive has a metal oxide purity in a range between 90 and 100 percent purity. [61] Fuel cell or fuel cell component according to claim 51, wherein each of the first additive and the second additive has a metal oxide purity in a range between 99 and 100 percent purity. [62] Fuel cell or fuel cell component comprising: a first layer comprising a first ionomer and an additive, wherein the additive comprises a metal oxide which contains an oxide of at least one of Mn, V, Pt, Ru, Zr, Ni, Cr, W, Co or Mo, and wherein the additive is present in an amount of at least 0.1 wt% of the ionomer and the additive consists of nanoparticles. [63] Fuel cell or fuel cell component according to claim 62, wherein the additive has a metal oxide purity in a range between 90 and 100 percent purity. [64] Fuel cell or fuel cell component according to claim 62, wherein the additive has a metal oxide purity in a range between 99 and 100 percent purity.

Images