# US 10,320,013 B2 · Hydrophobized gas diffusion layers and method of making the same

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 10,320,013 B2
- Document ID: US10320013B2
- Status: Granted
- Kind: B2
- Application number: 15/815,804
- Filed: 2017-11-17
- Published: 2018-04-26
- Granted: 2019-06-11
- Earliest claimed: 2012-01-27
- Assignees: University of Kansas
- Applicants: University of Kansas
- Inventors: Trung Van Nguyen; Xuhai Wang
- Web page: https://patentgrep.com/patent/US10320013B2

## CPC

- H01M 8/04201: {Reactant storage and supply, e.g. means for feeding, pipes}
- H01M 8/0234: Carbonaceous material
- H01M 8/0245: in the form of layered or coated products
- H01M 8/1004: characterised by membrane-electrode assemblies [MEA] (H01M8/12 takes precedence)
- H01M 2008/1095: {Fuel cells with polymeric electrolytes}
- H01M 2300/0082: Organic polymers
- Y02E 60/50: Fuel cells
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- 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
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A gas diffusion layer having a first major surface and a second major surface which is positioned opposite to said first major surface and an interior between said first and second major surfaces is formed. The gas diffusion layer comprises a porous carbon substrate which is directly fluorinated in the interior and is substantially free of fluorination on at least one of the first major surfaces or the second major surfaces, and preferably both surfaces. The gas diffusion layer may be formed using protective sandwich process during direct fluorination or by physically or chemically removing the C—F atomic layer at the major surfaces, for example by physical plasma etching or chemical reactive ion etching.

## Claims

### Claim 1

A method for making a gas diffusion device comprising:
providing a porous carbon substrate having a first major surface and a second major surface which is positioned opposite to said first major surface and an interior between said first and second major surfaces, wherein said interior comprises interior pores with interior pore surfaces;
directly fluorinating the porous carbon substrate with fluorine gas;
wherein said interior pore surfaces are fluorinated;
wherein at least one of the first major surface and the second major surface is not substantially fluorinated.

### Claim 2 (depends on 1)

The method of claim 1 wherein said direct fluorinating step occurs at a temperature of about 300 to 400° C.

### Claim 3 (depends on 1)

The method of claim 1 wherein said direct fluorinating step occurs for about 30 minutes to 3 hours.

### Claim 4 (depends on 1)

The method of claim 1, further comprising:
protecting at least one of the first major surface and second major surface by contacting at least one surface with a protective layer;
removing said contact between said protective layer and said at least one surface.

### Claim 5 (depends on 4)

The method of claim 4 wherein said first major surface is protected by contacting the first major surface with a first protective layer and said second major surface is protected by contacting the second major surface with a second protective layer such that the porous carbon substrate is sandwiched between the first protective layer and the second protective layer.

### Claim 6 (depends on 4)

The method of claim 4 wherein said protective layer is comprised of the same material comprising the porous carbon substrate.

### Claim 7 (depends on 5)

The method of claim 5 wherein said first protective layer and the second protective layer are both comprised of the same material comprising the porous carbon substrate.

### Claim 8 (depends on 1)

The method of claim 1 in which said porous carbon substrate comprises a macroporous carbon substrate adjacent a microporous carbon substrate such that the gas diffusion layer is a bilayer having said first major surface comprised of the microporous carbon substrate and said second major surface comprised of the macroporous carbon substrate.

### Claim 9 (depends on 1)

The method of claim 1, wherein said direct fluorination step comprises contacting said interior pore surfaces with fluorine gas.

### Claim 10 (depends on 1)

The method of claim 1, wherein all of said interior pore surfaces are covered with fluorine.

### Claim 11 (depends on 1)

The method of claim 1, wherein the porous substrate is comprised of carbon fibers having thousands of carbon atomic layers;
wherein an outer carbon atomic layer of said fibers is fluorinated during said direct fluorination step; and
the method further comprising removing said outer carbon atomic layers of the carbon fibers forming at least one of said first and second major surfaces such that the interior of said gas device is fluorinated.

### Claim 12 (depends on 11)

The method of claim 11 wherein said removing step is performed by sanding the at least one major surface.

### Claim 13 (depends on 11)

The method of claim 11 wherein said removing step is performed by physical plasma etching the at least one major surface with an argon plasma.

### Claim 14 (depends on 11)

The method of claim 11 wherein said removing step is performed by reaction ion etching the at least one major surface using plasma and a reactive gas.

### Claim 15 (depends on 14)

The method of claim 14 wherein said reactive gas is SF6.

### Claim 16 (depends on 11)

The method of claim 11 wherein said removing step is performed by ion beam etching the at least one major surface.

### Claim 17 (depends on 11)

The method of claim 11 wherein said removing step comprises removing said outer carbon atomic layers of the carbon fibers forming both the first and second major surfaces such that the interior of said gas diffusion device is fluorinated and both said first major surface and said second major surface are not substantially fluorinated.

### Claim 18 (depends on 11)

The method of claim 11 in which said porous carbon substrate comprises a macroporous carbon substrate adjacent a microporous carbon substrate such that the gas diffusion layer is a bilayer having said first major surface comprised of the microporous carbon substrate and said second major surface comprised of the macroporous carbon substrate.

### Claim 19 (depends on 11)

The method of claim 11, wherein said direct fluorination step comprises contacting said interior pore surfaces with fluorine gas.

### Claim 20 (depends on 11)

The method of claim 11, wherein all of said interior pore surfaces are covered with fluorine.