# US 11,299,810 B2 · Barrier layer for corrosion protection in electrochemical devices

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- Number: US 11,299,810 B2
- Document ID: US11299810B2
- Status: Granted
- Kind: B2
- Application number: 14/761,782
- Filed: 2014-02-20
- Published: 2015-12-10
- Granted: 2022-04-12
- Earliest claimed: 2013-02-21
- Assignees: Greenerity GmbH
- Applicants: Solvicore GmbH & Co. KG
- Inventors: Jens-Peter Suchsland; Alessandro Ghielmi; Pia Braun
- Web page: https://patentgrep.com/patent/US11299810B2

## CPC

- C25B 11/073: characterised by the electrocatalyst material
- C25B 9/23: comprising ion-exchange membranes in or on which electrode material is embedded
- C25B 11/031: Porous electrodes
- C25B 11/032: Gas diffusion electrodes
- C25B 11/051: Electrodes formed of electrocatalysts on a substrate or carrier
- H01M 4/8605: {Porous electrodes}
- H01M 4/8657: {layered}
- H01M 8/0234: Carbonaceous material
- H01M 8/0245: in the form of layered or coated products
- H01M 4/8615: {Bifunctional electrodes for rechargeable cells}
- H01M 2008/1095: {Fuel cells with polymeric electrolytes}
- H01M 2300/0082: Organic polymers
- Y02E 60/50: Fuel cells
- C25B: ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR (anodic or cathodic protection C23F13/00; single-crystal growth C30B)
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

The invention is directed to a barrier layer for corrosion protection in electrochemical devices, e.g. carbon based gas diffusion layers (GDLs) in electrochemical devices, comprising electrically conductive ceramic material and a non-ionomeric polymer binder. The electrically conductive ceramic material has an electrical conductivity of >0.1 S/cm, preferably >1 S/cm in air atmosphere (as detected by the powder method) and is selected from the group of precious metal and/or base metal containing oxides, carbides, nitrides, borides and mixtures and combinations thereof. Membrane-electrode assemblies (MEAs), catalyst-coated membranes (CCMs), gas diffusion electrodes (GDEs) and gas diffusion layers (GDLs) comprising the barrier layer of the invention show improved corrosion resistance, preferably against carbon corrosion; particularly in start-up/shut-down cycles and fuel starvation situations of PEM fuel cells.

## Claims

### Claim 1

A membrane-electrode assembly or a catalyst-coated membrane comprising at least one barrier layer, wherein the membrane-electrode assembly further comprises a catalyst layer and a gas diffusion layer and the barrier layer is positioned between the catalyst layer and the gas diffusion layer, wherein the catalyst-coated membrane further comprises an ionomer membrane and two catalyst layers and the barrier layer is positioned on at least one of the catalyst layers, wherein said barrier layer comprises electrically conductive ceramic material and a non-ionometic polymer binder, and wherein the barrier layer is a distinct layer from the gas diffusion layer and from any microporous layers attached to the gas diffusion layer,
wherein the electrically conductive ceramic material is selected from the group consisting of iridium-tantalum oxides (IrxTa1−xO2), ruthenium-titanium oxides (RuxTi1−xO2), titanium diboride (TiB2), molybdenum nitride (Mo2N), tantalum carbide (TaCx), tantalum carbonitride (TaCxN1−x), tungsten carbide (WC), titanium carbide (Tic), titanium nitride (TiN), titanium oxynitride (TiON), niobium doped titanium oxides (NbxTi1−xO2), nickel tantalum carbide (NixTayCz), niobium doped tin dioxide (NbxSn1−xO2) and mixtures and combinations thereof and
wherein the non-ionomeric polymer binder is selected from the group consisting of polytetralluoroethylene (PTFE), ethylene/tetraflutoroethylene copolymers (ETFE), fluorinated ethylene/propylene copolymers (FEP), tetrafluoroethylene/perfluoroalkoxyvinyl copolymers (PFA), polyvinylidene fluoride (PVDF), vinylidene fluoride (VDF) copolymers, tetrafluoroethylene/hexafluoropropylene/vinylidene fluoride terpolymers (THV), perfluoro rubbers (PFR), glassy amorphous fluoropolymers and mixtures and combinations thereof.

### Claim 2 (depends on 1)

The membrane-electrode assembly or a catalyst-coated membrane according to claim 1, wherein the electrically conductive ceramic material has an electrical conductivity of >0.1 S/cm in air atmosphere.

### Claim 3

The membrane-electrode assembly or a catalyst-coated membrane according to claim I, wherein the electrically conductive ceramic material has a high acid stability showing a solubility of <10−3 mol/l upon acidic treatment in 1 M H2SO4 at 90° C.

### Claim 4 (depends on 1)

The membrane-electrode assembly or a catalyst-coated membrane according to claim 1, wherein the electrically conductive ceramic material is selected from the group consisting of iridium-tantalum oxide (IrxTa1−xO2), ruthenium-titanium oxide (RuxTi1−xO2), titanium diboride (TiB2), molybdenum nitride (Mo2N), tantalum carbide (TaCx) and tantalum carbonitride (TaCxNy).

### Claim 5 (depends on 1)

The membrane-electrode assembly or a catalyst-coated membrane according to claim 1, wherein the electrically conductive ceramic material is a conductive oxide supported on a non-conductive oxide.

### Claim 6 (depends on 1)

The membrane-electrode assembly or a catalyst-coated membrane according to claim 1, wherein the weight ratio between the conductive material and the polymer binder is in the range of 0.5 to 50 wt. % based on the total weight of the dry layer composition.

### Claim 7 (depends on 1)

The membrane-electrode assembly or a catalyst-coated membrane according to claim 1 having a layer thickness after drying in the range of 0.1 to 100 microns.

### Claim 8 (depends on 1)

An electrochemical device comprising the membrane-electrode assembly or a catalyst-coated membrane according to claim 1, wherein the barrier layer is on the cathode side, the anode side or both sides of said electrochemical device.

### Claim 9

A gas diffusion electrode comprising a carbon-based gas diffusion layer and a barrier layer which comprises electrically conductive ceramic material and a non-ionomeric polymer binder and wherein a catalyst layer is coated on the barrier layer and
wherein the barrier layer is a distinct layer from the gas diffusion layer and from any microporous layers attached to the gas diffusion layer,
wherein the electrically conductive ceramic material is selected from the group consisting of iridium-tantalum oxides (IrxTa1−xO2), ruthenium-titanium oxides (RuxTi1−xO2) titanium diboride (TiB2), molybdenum nitride (Mo2N), tantalum carbide (TaCx), tantalum carbonitride (TaCxN1−x), tungsten carbide (WC), titanium carbide (TiC), titanium nitride (TiN), titanium oxynitride (TiON), niobium doped titanium oxides (NbxTi1−xO2), nickel tantalum carbide (NixTayCz), niobium doped tin dioxide (NbxSn1−xO2) and mixtures and combinations thereof, and
wherein the non-ionomeric polymer binder is selected from the group consisting of polytetrafluoroethylene (PTFE), ethylene/tetrafluoroethylene copolymers (ETFE), fluorinated ethylene/propylene copolymers (FEP) tetrafluoroethylene/perfluoroalkoxyvinyl copolymers (PFA), polyvinylidene fluoride (PVDF), vinylidene fluoride (VDF) copolymers, tetrafluoroethylene/hexafluoropropylene/vinylidene fluoride terpolvmers (THV), perfluoro rubbers (PFR), glassy amorphous fluoropolymers and mixtures and combinations thereof.

### Claim 10

An electrochemical device selected from the group of PEM fuel cells, PEM electrolysers, regenerative PEM fuel cells, redox-flow batteries and batteries comprising a barrier layer which comprises electrically conductive ceramic material and a non-ionomeric polymer binder,
wherein the barrier layer is a distinct layer from any gas diffusion layer present in the device or from any microporous layers attached to the gas diffusion layer,
wherein the electrically conductive ceramic material is selected from the group consisting of iridium-tantalum oxides (IrxTa1−xO2), ruthenium-titanium oxides (RuxTi1−xO2), titanium diboride (TiB2), molybdenum nitride (Mo2N), tantalum carbide (TaCx), tantalum carbonitride (TaCxN1−x), tungsten carbide (WC), titanium carbide (TiC), titanium nitride (TiN), titanium oxynitride (TiON), niobium doped titanium oxides (NbxTi1−xO2), nickel tantalum carbide (NixTayCz), niobium doped tin dioxide (NbxSn1−xO2) and mixtures and combinations thereof, and
wherein the non-ionomeric polymer binder is selected from the group consisting of polytetrafluoroethvlene (PTFE), ethylene/tetrafluoroethylene copolymers (ETFE), fluorinated ethylene/propylene copolymers (FEP), tetrafluoroethylene/perfluoroalkoxyvinyl copolymers (PFA), polyvinylidene fluoride (PVDF), vinylidene fluoride (VDF) copolymers, tetrafluoroethylene/hexafluoropropylene/vinylidene fluoride terpolymers (THV), perfluoro rubbers (PFR), glassy amorphous fluoropolymers and mixtures and combinations thereof.

### Claim 11 (depends on 2)

The membrane-electrode assembly or a catalyst-coated membrane according to claim 2, wherein the electrically conductive ceramic material has an electrical conductivity of >10 S/cm in air atmosphere (as detected by the powder method).

### Claim 12 (depends on 3)

The membrane-electrode assembly or a catalyst-coated membrane according to claim 3, wherein the electrically conductive ceramic material has a high acid stability showing a solubility of <10−4 mol/l upon acidic treatment in 1 M H2SO4 at 90° C.

### Claim 13 (depends on 6)

The membrane-electrode assembly or a catalyst-coated membrane according to claim 6, wherein the weight ratio between the conductive material and the polymer binder is in the range of 1 to 25 wt.-% based on the total weight of the dry layer composition.