Gas diffusion layer with double-microporous layer structure and preparation method thereof

A technology of gas diffusion layer and microporous layer, applied in the direction of fuel cells, structural parts, electrical components, etc. Material particle size selection space is limited and other issues

Active Publication Date: 2021-09-14
SHANDONG RENFENG SPECIAL MATERIALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the particle size of carbon powder is generally in the range of 30-40nm, and the particle size selection space of carbon powder material is limited. The double microporous layer prepared by using carbon powder with different particle sizes will make the pore size distribution gradient of the gas diffusion layer different. Obviously, there is a limit to improving the drainage capacity of the gas diffusion layer and the comprehensive performance of the fuel cell.

Method used

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  • Gas diffusion layer with double-microporous layer structure and preparation method thereof
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  • Gas diffusion layer with double-microporous layer structure and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0063] (1) Preparation of carbon paper support layer

[0064] Firstly, the carbon paper base paper is prepared by the wet papermaking process, and the basis weight is 43±5g / m 2 ; Secondly, the base paper is dipped and coated with thermosetting phenolic resin, and the coating weight is 1 times that of the base paper; again, the hot-pressing treatment is carried out, the hot-pressing pressure is 5MPa, the hot-pressing temperature is 180°C, and the hot-pressing time is 20min; finally, the The base material is carbonized and graphitized, the carbonization temperature is 1200°C, the carbonization time is 1h, the graphitization temperature is 2200°C, the graphitization time is 1h, and finally the carbon paper product as the support layer is obtained.

[0065] (2) Preparation of slurry

[0066] A. Preparation of carbon paper hydrophobic treatment slurry: take 60wt% aqueous polytetrafluoroethylene (PTFE) emulsion, add deionized water to dilute to 10wt% PTFE mass fraction, stir evenly...

Embodiment 2

[0080] (2) Preparation of slurry

[0081]B. Prepare the coating slurry for the first microporous layer: mix carbon fiber powder, sodium carboxymethyl cellulose, benzenesulfonyl hydrazide foaming agent, and deionized water in a ratio of 15:2:3:80 for later use, and then Transport to the foam slurry storage device for standby, and maintain a low-speed stirring state to ensure good distribution of carbon fiber powder in the foam, the concentration of the slurry is 15wt%.

[0082] Other steps are identical with embodiment 1.

[0083] The performance parameters of the final gas diffusion layer product are shown in Table 1.

Embodiment 3

[0085] (2) Preparation of slurry

[0086] C. Preparation of the second microporous layer coating slurry: first, ethanol, isopropanol and water are mixed uniformly in a ratio of 4:4:2; then, weigh carbon powder (Cabot, VXC-72R) and add ethanol / In the mixed solvent of isopropanol / water, the ratio of carbon powder to mixed solvent is 1:9, and the concentration of carbon powder is 10wt%. Use a double planetary mixer to stir at a low speed of 300rpm at room temperature until the carbon powder is completely covered with alcohol. After the solution is wrapped, carry out high-speed shear dispersion at a speed of 1500rpm, and finally fully mix the carbon powder and the solvent to obtain a continuous and uninterrupted uniform black oily liquid; then add 10wt% sodium chloride aqueous solution, and the amount added is 100% of the carbon powder. 3wt%, medium speed (800rpm) and stir evenly; finally, weigh 10wt% PTFE suspension with 43wt% of the amount of carbon powder (according to solute)...

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Abstract

The invention provides a gas diffusion layer with a double-microporous layer structure, the double-microporous layer comprises a first microporous layer and a second microporous layer, the first microporous layer is close to a support layer and is a carbon fiber powder layer with the thickness of 10-20 microns; and the second microporous layer is directly contacted with the catalyst layer and is a carbon powder layer with the thickness of 10-30 microns. Nano-scale and micron-scale holes exist in the surface of the microporous layer at the same time, and the flatness is high, so that the contact resistance is reduced; gradient pores with gradually reduced pore sizes from the supporting layer to the carbon fiber powder layer and then to the carbon powder layer are formed in the gas diffusion layer, so that on one hand, the pore structure distribution of the microporous layer is adjusted, and the water and gas management capability is improved; on the other hand, the coating formula and performance of the microporous layer are optimized, the conductivity of carbon fiber powder is higher than that of carbon powder, the conductivity of the system can be greatly improved by adding the carbon fiber powder layer, and effective transmission of electrons is promoted.

Description

technical field [0001] The invention relates to a gas diffusion layer for a hydrogen fuel cell, in particular to an optimized design and a preparation method of a microporous layer of a gas diffusion layer of a proton exchange membrane fuel cell, and belongs to the technical field of hydrogen fuel cell materials. Background technique [0002] Hydrogen energy fuel cells are an important direction for the transformation and upgrading of China's automobile power system and new energy vehicle strategy. "Made in China 2025" and "Medium and Long-term Development Plan of the Automobile Industry" and other plans have listed the development of hydrogen energy and fuel cell technology as a key task , listing fuel cell vehicles as a key area of ​​support. [0003] The gas diffusion layer is one of the core materials of hydrogen fuel cell stacks. At present, it mainly relies on imports, which seriously restricts the development of the hydrogen fuel cell industry. During the operation o...

Claims

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Application Information

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IPC IPC(8): H01M4/86H01M4/88H01M8/0234H01M8/0245B82Y30/00B82Y40/00
CPCH01M4/8605H01M4/8657H01M4/8807H01M8/0234H01M8/0245B82Y30/00B82Y40/00Y02E60/50
Inventor 汤秀秀宋佃凤郁国强刘娜何冬梅吴立群
Owner SHANDONG RENFENG SPECIAL MATERIALS
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