CN117117209A

CN117117209A - Gas diffusion layer and preparation method and application thereof

Info

Publication number: CN117117209A
Application number: CN202311379567.XA
Authority: CN
Inventors: 王志昌; 刘汉东; 宋孟刚; 张朔; 何星; 黄慧慧; 李吉涛; 张爱京; 周明正; 柴茂荣
Original assignee: Wuhan Lvdong Hydrogen Energy Technology Co ltd; Spic Hydrogen Energy Technology Development Co Ltd
Current assignee: Wuhan Lvdong Hydrogen Energy Technology Co ltd; Spic Hydrogen Energy Technology Development Co Ltd
Priority date: 2023-10-24
Filing date: 2023-10-24
Publication date: 2023-11-24
Anticipated expiration: 2043-10-24
Also published as: CN117117209B

Abstract

The application discloses a gas diffusion layer and a preparation method and application thereof, wherein the gas diffusion layer comprises a substrate layer, a first microporous layer and a second microporous layer, and the substrate layer is a carbon material layer loaded with a first hydrophobizing agent and a first rare earth oxide; the first microporous layer is arranged on the surface of the substrate layer, and the material of the first microporous layer contains a first conductive agent and a second hydrophobic agent; the second microporous layer is arranged on the surface of one side of the first microporous layer far away from the substrate layer, and the material of the second microporous layer contains a second rare earth oxide, a second conductive agent and a third hydrophobic agent. The gas diffusion layer, the basal layer, the first microporous layer and the second microporous layer all have hydrophobicity, the basal layer contains the first rare earth oxide of the free radical quencher, and the second microporous layer contains the second rare earth oxide of the precursor of the free radical quencher, so that free radicals generated in the reaction process of the fuel cell can be effectively eliminated, the proton membrane is protected, and the durability of the membrane electrode is greatly improved.

Description

Gas diffusion layer and preparation method and application thereof

Technical Field

The application relates to the technical field of fuel cells, in particular to a gas diffusion layer and a preparation method and application thereof.

Background

The PEMFC (proton exchange membrane fuel cell) has the advantages of low working temperature, high energy conversion efficiency and no pollution, and is concerned by vast experts and scholars. MEA (membrane electrode seven-in-one assembly) is usually composed of proton exchange membrane, catalyst and GDL (gas diffusion layer), and is a key component of PEMFC. The GDL mainly plays roles of supporting a catalytic layer, draining water, transmitting gas, conducting electricity and the like, and mainly influences the performance of the fuel cell under high current density, so that the upper limit of the performance is determined. The proton exchange membrane is used as a core component of the PEMFC, the proton conductivity of the proton exchange membrane directly influences the performance of the cell, and the durability directly determines the service life of the whole fuel cell. In practical application, the proton exchange membrane is degraded, so that the problems of hydrogen permeation, leakage and the like are very easy to occur. This would present a great safety hazard to the operation of the fuel cell and even directly render it unusable. There are three forms of degradation of the proton exchange membrane, the key components in the membrane electrode, including: thermal degradation, physical degradation, and chemical degradation, wherein chemical degradation is fatal and irreversible to the proton membrane, and chemical degradation is mainly represented by free radical attack, thereby changing the structure thereof. In the course of the reaction of the fuel cell, a large amount of free radicals, OH and OOH, are often generated, and attack side chains and end chains on the proton membrane perfluorosulfonic acid resin, resulting in a structural change thereof, thereby impairing the lifetime of the proton membrane. Thus, to achieve the long life objective of fuel cells, relief of PEM degradation is highly desirable. The existing fuel cell can not eliminate free radicals generated in the reaction process, so that the service life of the fuel cell is prolonged, and the performance and the service life of the fuel cell are prolonged only by means of external conditions, such as: control strategies, durability of proton membrane materials, and the like.

After new energy such as solar energy, wind energy and the like are rapidly developed, hydrogen energy is gradually the most potential clean energy, and the problem of short service life of a proton exchange membrane in a hydrogen fuel cell is based on diversification of application scenes of the hydrogen fuel cell, so that the degradation rate of the proton exchange membrane can be relieved through improvement of a gas diffusion layer, and therefore, the demand of a gas diffusion layer product with high performance and long service life is urgent.

Disclosure of Invention

Accordingly, an object of the present application is to provide a gas diffusion layer, wherein the base layer, the first microporous layer and the second microporous layer are all hydrophobic, and the base layer contains a radical quencher first rare earth oxide, and the second microporous layer contains a radical quencher precursor second rare earth oxide, so that radicals generated in the reaction process of the fuel cell can be efficiently eliminated, and the proton membrane is protected, thereby greatly improving the durability of the membrane electrode.

Another object of the present application is to provide a method for manufacturing a gas diffusion layer.

It is yet another object of the present application to provide a membrane electrode.

It is yet another object of the present application to provide a fuel cell.

To achieve the above object, an embodiment of a first aspect of the present application provides a gas diffusion layer, including:

A base layer, which is a carbon material layer loaded with a first hydrophobizing agent and a first rare earth oxide;

the first microporous layer is arranged on the surface of the substrate layer, and the material of the first microporous layer contains a first conductive agent and a second hydrophobic agent;

the second microporous layer is arranged on the surface of one side, far away from the substrate layer, of the first microporous layer, and the material of the second microporous layer contains a second rare earth oxide, a second conductive agent and a third hydrophobic agent.

In some embodiments, the first rare earth oxide and the second rare earth oxide each comprise at least one of cerium oxide, lanthanum oxide, praseodymium oxide.

In some embodiments, the first, second, and third hydrophobic agents each comprise at least one of polytetrafluoroethylene, vinylidene fluoride, and polyvinylidene fluoride.

In some embodiments, the first and second conductive agents each include at least one of carbon black, acetylene black, ketjen black, graphite powder, expanded graphite, carbon nanotubes.

In some embodiments, the carbon material layer comprises at least one of carbon paper, carbon cloth, carbon black paper.

In some embodiments, the carbon material layer is a coil.

In some embodiments, the first microporous layer has a thickness of 20-30 μm.

In some embodiments, the second microporous layer has a thickness of 5-10 μm.

In some embodiments, the first microporous layer has an average pore size of 1 to 30 μm.

In some embodiments, the second microporous layer has an average pore size of 0.5 to 20 μm.

In some embodiments, the loading of the first hydrophobic agent on the carbon material layer is 5-20wt%.

In some embodiments, the loading of the first rare earth oxide on the carbon material layer is 0.2-5wt%.

In some embodiments, the mass ratio of the first conductive agent to the second hydrophobic agent is 1 (0.1-1).

In some embodiments, the mass ratio of the second rare earth oxide, the second conductive agent, and the third hydrophobic agent is (0.1-0.35): 1: (0.1-1).

In some embodiments, the mass ratio of the first rare earth oxide to the second rare earth oxide is (0.05-0.5): 1.

in order to achieve the above object, a second aspect of the present application provides a method for preparing a gas diffusion layer, comprising:

dipping the carbon material layer in a dipping liquid containing a first rare earth oxide, a first hydrophobizing agent and first solvent water for hydrophobizing treatment to obtain a substrate layer;

Forming a first microporous layer containing a first conductive agent and a second hydrophobic agent on the surface of the substrate layer to obtain a first composite material layer;

forming a second microporous layer containing rare earth salt, a second conductive agent and a third hydrophobic agent on the surface of the first microporous layer, which is far away from the substrate layer, in the first composite material layer to obtain a second composite material layer;

and carrying out heat treatment on the second composite material layer to obtain the gas diffusion layer.

In some embodiments, the impregnation fluid comprises a mass ratio of the first hydrophobizing agent, the first rare earth oxide, and the first solvent of (0.4-0.8): (0.01-0.05): (8-14).

In some embodiments, the immersion time is 3-10 minutes.

In some embodiments, the carbon material layer is a coil.

In some embodiments, the temperature of the heat treatment is 350-450 ℃, and the time of the heat treatment is 20-40min.

In some embodiments, the first rare earth oxide comprises at least one of cerium oxide, lanthanum oxide, praseodymium oxide.

In some embodiments, the rare earth salt comprises at least one of a cerium salt, a lanthanum salt, a praseodymium salt.

In some embodiments, the mass ratio of the first rare earth oxide to the rare earth salt is (0.01-0.2): 1.

in some embodiments, the first solvent comprises at least one of water, ethanol, isopropanol.

In some embodiments, forming the first microporous layer on the substrate layer surface comprises:

mixing a second solvent, a first surfactant and a first conductive agent to obtain a first slurry;

adding a second hydrophobic agent into the first slurry, and uniformly mixing to obtain first microporous layer slurry;

forming the first microporous layer slurry on the surface of the substrate layer through first coating, and then carrying out first drying to obtain a first composite material layer;

in some embodiments, forming the second microporous layer on a surface of the first microporous layer on a side of the first composite layer remote from the substrate layer comprises:

Performing first ball milling on rare earth salt and a third solvent to obtain second slurry;

performing second ball milling on the second conductive agent, the fourth solvent and the second surfactant to obtain third slurry;

adding the third slurry into the second slurry for multiple times, and uniformly mixing the second slurry through a third ball mill to obtain fourth slurry;

adding a third hydrophobic agent into the fourth slurry twice, and uniformly mixing to obtain second microporous layer slurry;

and forming the second microporous layer slurry on the surface of the first microporous layer far away from the substrate layer in the first composite material layer through second coating, and then carrying out second drying and third drying treatment to obtain the second composite material layer.

In some embodiments, the mass ratio of the first conductive agent, the second hydrophobic agent, the second solvent, the first surfactant is (15-21): (4-8): (150-250): (7-13).

In some embodiments, the rare earth salt, the second conductive agent, the third hydrophobic agent, the third solvent, the fourth solvent, the second surfactant are in a mass ratio of (3-5): (16-24): (5.5-8.3): (84-124): (160-240): (4-6).

In some embodiments, the second solvent comprises at least one of water, isopropanol, n-propanol, ethanol, n-butanol.

In some embodiments, the first surfactant comprises at least one of Triton-X100, tween 60, polyethylene glycol isooctylphenyl ether, fatty alcohol polyoxyethylene ether.

In some embodiments, the third solvent and the fourth solvent each comprise at least one of ethylene glycol, glycerol, mannitol, water.

In some embodiments, the second surfactant comprises at least one of sodium dodecyl benzene sulfonate, polyvinyl alcohol, polyacrylic acid.

In some embodiments, the temperature of the first drying and the second drying are each 70-90 ℃, and the time of the first drying and the second drying are each 5-15min.

In some embodiments, the temperature of the third drying is 200-300 ℃, and the time of the third drying is 10-20min.

In some embodiments, the first coating and the second coating are by slot die coating or knife coating.

In order to achieve the above object, an embodiment of the third aspect of the present application provides a membrane electrode, which includes the gas diffusion layer according to the embodiment of the present application or the gas diffusion layer prepared by the method for preparing the gas diffusion layer according to the embodiment of the present application.

In order to achieve the above object, a fourth aspect of the present application provides a fuel cell including the membrane electrode according to the embodiment of the present application.

The gas diffusion layer provided by the embodiment of the application has at least the following beneficial effects:

the substrate layer, the first microporous layer and the second microporous layer all have hydrophobicity, the substrate layer contains a radical quencher first rare earth oxide, and the second microporous layer contains a radical quencher precursor second rare earth oxide, so that free radicals generated in the reaction process of the fuel cell can be effectively eliminated, the proton membrane is protected, and the durability of the membrane electrode is greatly improved.

The preparation method of the gas diffusion layer provided by the embodiment of the application has the beneficial effects of at least the following advantages in addition to the beneficial effects of the gas diffusion layer provided by the embodiment of the application:

1. the free radical quencher precursor (namely rare earth salt) is added in the preparation process of the second microporous layer, gas volatilization is generated during the subsequent heat treatment pyrolysis, meanwhile, the porous ceramic material can serve as a pore-forming agent, a plurality of gas-guiding and water-draining gradient holes can be prepared in a directional manner, the water-gas management capacity of the gas diffusion layer is increased, the water-gas management capacity of the membrane electrode of the fuel cell is improved, and the performance of the corresponding fuel cell is also synchronously and greatly improved.

2. The carbon material layer adopts coiled materials, the first microporous layer and the second microporous layer are formed by adopting slit extrusion coating, doctor blade coating and other modes, and the roll-to-roll automatic process has high production efficiency and is beneficial to batch production.

Additional aspects and advantages of the application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the application.

Drawings

The foregoing and/or additional aspects and advantages of the application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:

fig. 1 is a schematic view showing the structure of a gas diffusion layer according to an exemplary embodiment (embodiment 1) of the present application.

Fig. 2 is a flowchart illustrating a method of manufacturing a gas diffusion layer according to an exemplary embodiment of the present application.

Fig. 3 is a graph showing comparison of cell performance of comparative example 1 and example 1.

Reference numerals:

1-a substrate layer; 101-a first rare earth oxide; 2-a first microporous layer; 201-a second hydrophobic agent; 202-a first conductive agent; 3-a second microporous layer; 301-a second rare earth oxide; 302-a second conductive agent; 303-third hydrophobe.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings. The embodiments described below by referring to the drawings are illustrative and intended to explain the present application and should not be construed as limiting the application.

In the application, the disclosure of numerical ranges includes disclosure of all values and further sub-ranges within the entire range, including endpoints and sub-ranges given for these ranges.

In the application, the related raw materials, equipment and the like are all raw materials and equipment which can be self-made by commercial paths or known methods unless specified otherwise; the methods involved, unless otherwise specified, are all conventional.

The application aims to solve the problems of short service life and poor battery performance of a fuel battery. The inventors found that the key to impair chemical degradation is to eliminate active radicals such as OH, OOH, etc. CeO (CeO) ₂ The same rare earth oxide can effectively achieve this object. In an acidic environment, e.g., ce ³⁺ And Ce (Ce) ⁴⁺ Respectively undergo reduction and oxidation reactions with the active free radicals, thereby eliminating the active free radicals. The reaction formula is as follows:

Ce ³⁺ ＋HO.＋H ⁺ →Ce ⁴⁺ ＋H ₂ O（1）

Ce ⁴⁺ ＋H ₂ O ₂ →Ce ³⁺ ＋HOO.＋H ⁺ （2）

Ce ⁴⁺ ＋HOO.→Ce ³⁺ ＋O ₂ ＋H ⁺ （3）。

based on the findings, the application combines the operation process of the fuel cell, and by carrying out integral design on the Gas Diffusion Layer (GDL), in the process of preparing the GDL, the free radical quencher rare earth oxide is introduced in the hydrophobic treatment process of the carbon material layer such as carbon paper, the free radical quencher precursor rare earth salt is introduced in the microporous layer, and then the GDL containing the free radical quencher rare earth oxide is obtained through high-temperature heat treatment, the free radical generated in the reaction process of the fuel cell can be effectively eliminated, and the proton membrane is protected, thereby greatly improving the durability of the membrane electrode. In addition, the free radical quencher precursor rare earth salt added into the GDL can volatilize gas during high-temperature decomposition, can serve as a pore-forming agent, can directionally prepare a plurality of air guide and water drainage gradient holes, and increases the water-gas management capacity of the gas diffusion layer, so that the water-gas management capacity of the membrane electrode of the fuel cell is improved, and the performance of the corresponding fuel cell is also synchronously and greatly improved. The application can not only improve the performance of the membrane electrode, but also greatly improve the durability of the membrane electrode.

The gas diffusion layer, the method of manufacturing the gas diffusion layer according to the embodiment of the application are described below with reference to the drawings.

Fig. 1 is a schematic view showing a structure of a gas diffusion layer according to an exemplary embodiment of the present application.

As shown in fig. 1, the gas diffusion layer according to the embodiment of the present application includes a base layer 1, a first microporous layer 2 and a second microporous layer 3, where the base layer 1 is a carbon material layer loaded with a first hydrophobizing agent and a first rare earth oxide 101; the first microporous layer 2 is arranged on the surface of the substrate layer 1, and the material of the first microporous layer 2 contains a first conductive agent 202 and a second hydrophobic agent 201; the second microporous layer 3 is disposed on a surface of the first microporous layer 2 on a side remote from the base layer 1, and the material of the second microporous layer 3 contains a second rare earth oxide 301, a second conductive agent 302, and a third hydrophobizing agent 303.

It will be appreciated that in embodiments of the present application, the substrate layer 1, the first microporous layer 2 and the second microporous layer 3 are sequentially stacked.

The gas diffusion layer, the basal layer, the first microporous layer and the second microporous layer of the embodiment of the application have hydrophobicity, the basal layer contains the first rare earth oxide of the free radical quencher, and the second microporous layer contains the second rare earth oxide of the precursor of the free radical quencher, so that the free radicals generated in the reaction process of the fuel cell can be effectively eliminated, the proton membrane is protected, and the durability of the membrane electrode is greatly improved.

In some embodiments, the first rare earth oxide 101 and the second rare earth oxide 301 each include, but are not limited to, at least one of cerium oxide, lanthanum oxide, praseodymium oxide, and the like.

As an alternative example, both the first rare earth oxide 101 and the second rare earth oxide 301 employ cerium oxide.

In some embodiments, the first hydrophobic agent, the second hydrophobic agent, the third hydrophobic agent each include, but are not limited to, at least one of polytetrafluoroethylene, vinylidene fluoride, polyvinylidene fluoride, and the like.

As an alternative example, polytetrafluoroethylene is used as the first hydrophobizing agent, the second hydrophobizing agent, and the third hydrophobizing agent.

In some embodiments, the first conductive agent and the second conductive agent each include, but are not limited to, at least one of carbon black, acetylene black, ketjen black, graphite powder, expanded graphite, carbon nanotubes, and the like. Wherein the carbon black includes, but is not limited to, at least one of XC-72R, BP2000 and the like.

As an alternative example, XC-72R is used for both the first and second conductive agents.

It should be noted that, in the embodiment of the present application, the first rare earth oxide and the second rare earth oxide may be the same or different; the first hydrophobizing agent, the second hydrophobizing agent and the third hydrophobizing agent may be the same or different; the first conductive agent and the second conductive agent may be the same or different.

In some embodiments, the carbon material layer includes, but is not limited to, at least one of carbon paper, carbon cloth, carbon black paper, and the like.

In the embodiment of the present application, when the carbon material layer includes two or more of carbon paper, carbon cloth, carbon black paper, and the like, the carbon material layer may be a composite material layer of these materials, and the composite order of the materials is not limited.

As an alternative example, the carbon material layer is a carbon paper, including but not limited to a carbon paper having a thickness of 50-250 μm.

In some embodiments, the carbon material layer is a coil.

In some embodiments, the thickness of the first microporous layer 2 is 20-30 μm, including but not limited to 20 μm, 22 μm, 25 μm, 28 μm, 30 μm, or the like.

In some embodiments, the first microporous layer 2 has an average pore size of 1-30 μm, including but not limited to 1 μm, 5 μm, 15 μm, 20 μm, 25 μm, 30 μm, or the like.

In some embodiments, the thickness of the second microporous layer 3 is 5-10 μm, including but not limited to 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, etc.

In some embodiments, the second microporous layer 3 has an average pore size of 0.5 to 20 μm, including but not limited to 0.5 μm, 5 μm, 15 μm, 20 μm, or the like.

In some embodiments, the total thickness of the first microporous layer 2 and the second microporous layer 3 is 25-40 μm, including but not limited to 25 μm, 30 μm, 35 μm, 40 μm, or the like.

In some embodiments, the loading of the first hydrophobe on the carbon material layer is 5-20wt%, including but not limited to 5wt%, 10wt%, 15wt%, 20wt%, etc.

In some embodiments, the loading of the first rare earth oxide 101 on the carbon material layer is 0.2-5wt%, including but not limited to 0.2 wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, etc.

In some embodiments, the mass ratio of the first conductive agent to the second hydrophobic agent is 1 (0.1-1), including but not limited to 1:0.1, 1:0.25, 1:0.5, 1:0.75 or 1:1, etc.

In some embodiments, the mass ratio of the second rare earth oxide 301, the second conductive agent, and the third hydrophobic agent is (0.1-0.35): 1: (: 0.1-1), including but not limited to 0.1:1:0.1, 0.1:1: 1. 0.35:1:0.1, 0.35:1:1 or 0.23:1:0.55, etc.

In some embodiments, the mass ratio of the first rare earth oxide 101 to the second rare earth oxide 301 is (0.05-0.5): 1, including but not limited to 0.05: 1. 0.5: 1. 0.1: 1. 0.2: 1. 0.3:1 or 0.4:1, etc.

Fig. 2 is a flowchart illustrating a method of manufacturing a gas diffusion layer according to an exemplary embodiment of the present application. The method for preparing the gas diffusion layer according to the embodiment of the present application may be used to prepare the gas diffusion layer according to the embodiment of the present application, as shown in fig. 2, and includes the following steps:

S101, immersing the carbon material layer in an immersion liquid containing a first rare earth oxide, a first hydrophobizing agent and first solvent water for hydrophobizing treatment to obtain a substrate layer.

In the embodiment of the application, the free radical quencher first rare earth oxide is introduced into the hydrophobic process of the carbon material layer side, and the free radical quencher first rare earth ions of the carbon material layer side gradually move to the catalytic layer along with the migration of time, so that the service life of the GDL (gas diffusion layer) against free radicals in the operation process of the fuel cell is prolonged.

In some embodiments, the mass ratio of the first hydrophobizing agent, the first rare earth oxide, and the first solvent in the impregnation fluid is (0.4-0.8): (0.01-0.05): (8-14), including but not limited to 0.4:0.01: 8. 0.8:0.05:14 or 0.6:0.02:11, etc.

In some embodiments, the first hydrophobe may be first formulated into a first hydrophobe emulsion, wherein the first hydrophobe is present in the first hydrophobe emulsion in a mass content of 40-80%, including but not limited to 40%, 60%, 80%, etc.

In some embodiments, the first hydrophobic agent includes, but is not limited to, at least one of polytetrafluoroethylene, vinylidene fluoride, polyvinylidene fluoride, and the like, preferably polytetrafluoroethylene.

In some embodiments, the first rare earth oxide includes, but is not limited to, at least one of cerium oxide, lanthanum oxide, praseodymium oxide, etc., preferably cerium oxide, such as CeO ₂ 。

In some embodiments, the first solvent comprises at least one of water, ethanol, isopropanol, etc., wherein the water may be selected from ultrapure water, etc.

In some embodiments, the total mass of the first rare earth oxide, the first hydrophobizing agent, and the carbon material layer is 5-15% by mass, including but not limited to 5%, 8%, 10%, 13%, 15%, and the like.

In some embodiments, the soaking time is 3-10min, including but not limited to 3min, 5min, 10min, etc.

In some embodiments, the carbon material layer includes, but is not limited to, at least one of carbon paper, carbon cloth, carbon black paper, etc., preferably carbon paper.

In some embodiments, the carbon material layer is a coil.

S102, forming a first microporous layer containing a first conductive agent and a second hydrophobic agent on the surface of the substrate layer to obtain a first composite material layer.

In some embodiments, forming a first microporous layer on a surface of a substrate layer comprises the steps of:

(1) And mixing the second solvent, the first surfactant and the first conductive agent to obtain first slurry.

(2) And adding a second hydrophobic agent into the first slurry, and uniformly mixing to obtain the first microporous layer slurry.

(3) The first microporous layer slurry is formed on the surface of the substrate layer through first coating, and then is dried through first drying, so that a first composite material layer is obtained.

In some embodiments, the first conductive agent includes, but is not limited to, at least one of carbon black, acetylene black, ketjen black, graphite powder, expanded graphite, carbon nanotubes, and the like. Wherein the carbon black includes, but is not limited to, at least one of XC-72R, BP2000 and the like.

As an alternative example, XC-72R is used as the first conductive agent.

In some embodiments, the second hydrophobic agent includes, but is not limited to, at least one of polytetrafluoroethylene, vinylidene fluoride, polyvinylidene fluoride, and the like, preferably polytetrafluoroethylene.

In some embodiments, the second hydrophobic agent may be first formulated into a second hydrophobic agent emulsion, wherein the second hydrophobic agent is present in the second hydrophobic agent emulsion in a mass content of 40-80%, including but not limited to 40%, 60%, 80%, etc.

In some embodiments, the second solvent includes, but is not limited to, at least one of water, isopropyl alcohol, n-propyl alcohol, ethanol, n-butanol, and the like, preferably water.

In some embodiments, the first surfactant includes, but is not limited to, at least one of Triton-X100, tween 60, polyethylene glycol isooctylphenyl ether, fatty alcohol-polyoxyethylene ether, and the like, with Triton-X100 being preferred.

In some embodiments, the mass ratio of the first conductive agent, the second hydrophobic agent, the second solvent, and the first surfactant is (15-21): (4-8): (150-250): (7-13), including but not limited to 18:6:200: 10. 15:4:150:7 or 21:8:250:13, etc.

In some embodiments, the temperature of the first drying is 70-90 ℃, including but not limited to 70 ℃, 80 ℃, 90 ℃, or the like.

In some embodiments, the first drying time is 5-15 minutes, including but not limited to 5 minutes, 10 minutes, 15 minutes, or the like.

In some embodiments, in step (1), the second solvent, the first surfactant, and the first conductive agent are mixed by ball milling for a period of 1-3 hours at a ball milling speed of 400-600r/min.

In some embodiments, in step (2), the first slurry is mixed with the second hydrophobic agent using stirring, e.g., magnetic stirring, stirrer stirring, etc.

As a non-limiting example, the stirring time is 20-40min and the stirring speed is 250-350r/min.

In some embodiments, in step (2), the first microporous layer slurry is a black, light colored, ink-like substance.

In some embodiments, the manner of the first coating in step (3) includes, but is not limited to, slot die coating or knife coating, etc., preferably slot die coating.

In some embodiments, after the first drying in step (3), the dry thickness of the first microporous layer slurry (i.e., the thickness of the first microporous membrane) is controlled to be 20-30 μm.

S103, forming a second microporous layer containing rare earth salt, a second conductive agent and a third hydrophobic agent on the surface of the first microporous layer, which is far away from the substrate layer, in the first composite material layer, so as to obtain a second composite material layer.

In the embodiment of the application, the free radical quencher precursor rare earth salt is introduced into the second microporous layer which is far away from the substrate layer and is close to the catalytic layer when in use, so that the free radical quencher precursor rare earth salt can simultaneously play the roles of the pore forming agent and the free radical quencher, the water vapor management capability of the GDL is enhanced, and the corresponding performance is improved.

In some embodiments, the rare earth salt includes, but is not limited to, at least one of cerium salt, lanthanum salt, praseodymium salt, etc., preferably cerium salt.

As a non-limiting example, the cerium salt includes, but is not limited to, at least one of cerium nitrate salt, cerium sulfate salt, cerium chloride salt, and the like.

In some embodiments, the mass ratio of the first rare earth oxide to the rare earth salt is (0.01-0.2): 1, including but not limited to 0.01: 1. 0.05: 1. 0.1: 1. 0.15:1 or 0.2:1, etc.

In some embodiments, the second conductive agent includes, but is not limited to, at least one of carbon black, acetylene black, ketjen black, graphite powder, expanded graphite, carbon nanotubes, and the like. Wherein the carbon black includes, but is not limited to, at least one of XC-72R, BP2000 and the like.

As an alternative example, XC-72R is used as the second conductive agent.

In some embodiments, the third hydrophobic agent includes, but is not limited to, at least one of polytetrafluoroethylene, vinylidene fluoride, polyvinylidene fluoride, and the like, preferably polytetrafluoroethylene.

In some embodiments, the third hydrophobe may be first formulated into a third hydrophobe emulsion, wherein the third hydrophobe has a mass content of 40-80% in the third hydrophobe emulsion, including but not limited to 40%, 60%, 80%, etc.

In some embodiments, the manner in which the second microporous layer is formed on the surface of the first composite layer on the side of the first microporous layer remote from the substrate layer includes, but is not limited to, coating, and the like.

In some embodiments, forming a second microporous layer on a surface of the first microporous layer on a side of the first composite layer remote from the substrate layer comprises the steps of:

1) Performing first ball milling on rare earth salt and a third solvent to obtain second slurry;

2) Performing second ball milling on the second conductive agent, the fourth solvent and the second surfactant to obtain third slurry;

3) Adding the third slurry into the second slurry for multiple times, and uniformly mixing the second slurry by a third ball mill to obtain fourth slurry;

4) Adding a third hydrophobizing agent into the fourth slurry twice, and uniformly mixing to obtain second microporous layer slurry;

5) And forming second microporous layer slurry on the surface of the first microporous layer far away from the substrate layer in the first composite material layer through second coating, and then carrying out second drying and third drying treatment to obtain the second composite material layer.

In some embodiments, the rotational speed of the first ball mill is 800-1200r/min and the time of the first ball mill is 1.5-3 hours.

In some embodiments, the rotational speed of the second ball mill and the third ball mill are each 400-600 r/min, the time of the second ball mill is 1.5-3 hours, and the time of the third ball mill is 20-40 minutes.

In some embodiments, in step 3), the number of times is 2 or more.

In some embodiments, in step 3), the mass of the third slurry added each time may be equal, or unequal.

In some embodiments, in step 3), the third slurry is added to the second slurry in multiple portions and mixed by a third ball mill to obtain a fourth slurry, including but not limited to: and after adding the third slurry each time, performing third ball milling, and then adding a new part of the third slurry to perform third ball milling.

In some embodiments, in step 4), the third hydrophobic agent is added each time and mixed uniformly by stirring, including but not limited to magnetic stirring, stirring by a stirrer, etc., at a rotation speed of 250-350 r/min for 20-40min.

In some embodiments, the manner of the second coating in step 5) includes, but is not limited to, slot die coating or knife coating, etc., preferably slot die coating.

In some embodiments, the mass ratio of rare earth salt, second conductive agent, third hydrophobic agent, third solvent, fourth solvent, second surfactant is (3-5): (16-24): (5.5-8.3): (84-124): (160-240): (4-6), including but not limited to 4:20:6.9:104:200: 5. 3:16:5.5:84:160:4 or 5:24:8.3:124:240:6, etc.

In some embodiments, the third solvent and the fourth solvent each include, but are not limited to, at least one of ethylene glycol, glycerol, mannitol, water, and the like.

In some embodiments, the second surfactant includes, but is not limited to, at least one of sodium dodecyl benzene sulfonate, polyvinyl alcohol, polyacrylic acid, and the like.

In some embodiments, the temperature of the second drying is 70-90 ℃, including but not limited to 70 ℃, 80 ℃, 90 ℃, or the like.

In some embodiments, the second drying time is 5-15 minutes, including but not limited to 5 minutes, 10 minutes, 15 minutes, or the like.

In some embodiments, the temperature of the third drying is 200-300 ℃, including but not limited to 200 ℃, 230 ℃, 250 ℃, 2800 ℃, 300 ℃, or the like.

In some embodiments, the third drying time is 10-20 minutes, including but not limited to 10 minutes, 12 minutes, 15 minutes, 18 minutes, 20 minutes, or the like.

In the embodiment of the present application, the purpose of the second drying and the third drying is to completely volatilize the solvent (the third solvent and the fourth solvent).

In some embodiments, the second microporous layer slurry is coated to a dry thickness (i.e., the thickness of the second microporous layer) of 5-10 μm after the second drying and the third drying treatments, and the total thickness of the first microporous layer and the second microporous layer is controlled to 25-40 μm.

And S104, performing heat treatment on the second composite material layer to obtain the gas diffusion layer.

In an embodiment of the present application, the radical quencher precursor rare earth salt is converted to a radical quencher nano rare earth oxide (e.g., ceO ₂ Etc.), thus having nano rare earth oxide (e.g., ceO) ₂ Etc.) and porous structures. The precursor rare earth salt of the free radical quencher is used as both the free radical quencher and the pore-forming agent in the process.

In some embodiments, the temperature of the heat treatment is 350-450 ℃, including but not limited to 350 ℃, 375 ℃, 400 ℃, 425 ℃, 450 ℃, or the like.

In some embodiments, the time of heat treatment is 20-40 minutes, including but not limited to 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, or the like.

According to the preparation method of the gas diffusion layer, the free radical quencher is introduced when the base layer hydrophobic liquid is prepared, and after the carbon material layer is impregnated and subjected to hydrophobic treatment, the carbon material layer side has a free radical quenching function; when the microporous layer is prepared, a free radical quenching precursor is introduced, and simultaneously, the substance has the dual functions of a pore-forming agent and a free radical quenching agent through different temperature treatments; the design of a double-layer microporous layer is adopted, wherein the upper layer (namely a second microporous layer far away from the basal layer) is provided with a free radical quencher rare earth oxide, so that the free radical capturing efficiency is greatly improved, and the utilization rate and the capturing efficiency of the free radical quencher are improved; the carbon material layer adopts coiled materials, the first microporous layer and the second microporous layer are formed by adopting a slit extrusion coating mode or a doctor blade coating mode and the like, and the roll-to-roll automatic slit precise coating process has high production efficiency and high product precision and is beneficial to batch and continuous production.

The membrane electrode comprises the gas diffusion layer of the embodiment of the application or comprises the gas diffusion layer prepared by the preparation method of the gas diffusion layer of the embodiment of the application.

In some embodiments, the membrane electrode further comprises a proton exchange membrane, an anode catalytic layer and a cathode catalytic layer, wherein the anode catalytic layer and the cathode catalytic layer are respectively arranged at two sides of the proton exchange membrane, and the gas catalytic layer of the embodiment of the application is arranged at one side of the anode catalytic layer and the cathode catalytic layer, which is far away from the proton exchange membrane.

As an alternative example, the membrane electrode is a CCM membrane electrode.

In the embodiment of the application, the materials of the proton exchange membrane, the anode catalytic layer and the cathode catalytic layer are not limited, and can be any materials commonly used in the field.

The fuel cell of the embodiment of the application comprises the membrane electrode of the embodiment of the application.

Certain features of the present technology are further illustrated in the following non-limiting examples.

1. Examples and comparative examples

Example 1

(gas diffusion layer)

As shown in fig. 1, the gas diffusion layer of the present embodiment includes a base layer 1, a first microporous layer 2, and a second microporous layer 3, where the base layer 1 is a carbon material layer loaded with a first hydrophobizing agent and a first rare earth oxide 101; the first microporous layer 2 is arranged on the surface of the substrate layer 1, and the material of the first microporous layer 2 contains a first conductive agent 202 and a second hydrophobic agent 201; the second microporous layer 3 is disposed on a surface of the first microporous layer 2 on a side remote from the base layer 1, and the material of the second microporous layer 3 contains a second rare earth oxide 301, a second conductive agent 302, and a third hydrophobizing agent 303.

Wherein:

the first rare earth oxide 101 and the second rare earth oxide 301 are both CeO ₂ A nano powder; the first hydrophobizing agent, the second hydrophobizing agent and the third hydrophobizing agent are polytetrafluoroethylene; both the first conductive agent 202 and the second conductive agent 302 employ XC-72R; the carbon material layer was a rolled carbon paper (EP 40, avacarb company) having a thickness of 190 μm.

The mass ratio of the first rare earth oxide 101 to the first hydrophobizing agent is 0.02:0.6; the loading of the first hydrophobe on the carbon material layer was 9.68wt%; the loading of the first rare earth oxide 101 on the carbon material layer was 0.32wt%; the mass ratio of the first conductive agent 202 to the second hydrophobic agent 201 is 3:1, and the mass ratio of the second rare earth oxide 301, the second conductive agent 302 and the third hydrophobic agent 303 is 4:20:11.5; the mass ratio of the first rare earth oxide 101 to the second rare earth oxide 301 is 1:5.

The thickness of the first microporous layer 2 was 30 μm, and the average pore diameter of the first microporous layer 2 was 12 μm; the thickness of the second microporous layer 3 was 10 μm, and the average pore diameter of the second microporous layer 3 was 10.5 μm.

(method for producing gas diffusion layer)

The preparation method of the gas diffusion layer comprises the following steps:

s1, hydrophobic treatment of carbon paper: 50 parts by weight of PTEF emulsion (60% by weight of water as solvent; 1 part by weight of CeO) ₂ The nano powder and 550 parts by weight of ultrapure water are mixed together by adopting a mechanical stirring mode to form 4.99% wt concentration hydrophobic liquid. Then, a rolled carbon paper (EP 40, avacarb company) was continuously immersed in the above-mentioned hydrophobic liquid for 5 minutes to achieve a set target loading of 10wt% of ceria and hydrophobic agent PTFE, to obtain a base layer.

S2, preparing first microporous layer slurry A: firstly adding 200 parts by weight of ultrapure water, 10 parts by weight of Triton-X100 and 18 parts by weight of cabot XC-72R, ball milling for 2 hours at a rotating speed of 500R/min to form slurry A1 (namely first slurry), and then adding 10 parts by weight of PTFE emulsion (60% wt, solvent is water) and magnetically stirring for 30 minutes at a rotating speed of 300R/min to prepare first microporous layer slurry A.

S3, preparing second microporous layer slurry B: firstly, adding 4 parts by weight of cerium nitrate, 4 parts by weight of ethylene glycol and 100 parts by weight of water ball mill for 2 hours at a rotating speed of 1000r/min to form slurry B1 (namely second slurry); then ball milling 15 parts by weight of acetylene black, 5 parts by weight of single-walled carbon nanotube dispersion liquid (20 wt%, solvent is water and ethanol), 200 parts by weight of water and 5 parts by weight of sodium dodecyl benzene sulfonate for 2 hours at a rotating speed of 500r/min to form slurry B2 (namely third slurry); then, firstly adding 135 parts by weight of slurry B2 into the slurry B1, and ball-milling for 30min at a rotating speed of 500r/min to obtain mixed slurry; and adding the rest 90 parts by weight of slurry B2 into the mixed slurry of the slurry B1 and part (135 parts by weight) of slurry B2, ball milling for 2 hours at the rotating speed of 500r/min to form slurry B3 (namely fourth slurry), and finally adding 11.5 parts by weight of PTFE emulsion (60%wt, the solvent is water; the weights of the PTFE emulsion added for two times are equal) into the slurry B3 in two times, and magnetically stirring for 30 minutes at the rotating speed of 300r/min respectively to prepare the second microporous layer slurry B.

S4, coating the first microporous layer slurry A and the second microporous layer slurry B: continuously coating the first microporous layer slurry A on the coiled carbon paper substrate (namely the substrate layer) subjected to the hydrophobic treatment by using a slit extrusion coating mode, and then baking at 80 ℃ for 10 min to obtain a first composite material layer with the coating thickness of 30 mu m of the first microporous layer slurry A; and then coating the second microporous layer slurry B on the surface of the first microporous layer far away from the substrate layer in the first composite material layer by using a slit extrusion coating mode, baking at 80 ℃ for 10 min, wherein the thickness of the second microporous layer slurry B is 10 mu m, baking at 250 ℃ for 15min, and the thickness of the second microporous layer slurry B is still 10 mu m, so that the second composite material layer with the total thickness of the first microporous layer slurry A coating and the second microporous layer slurry B coating of 40 mu m is finally obtained.

S5, heat treatment: and carrying out heat treatment on the second composite material layer at 400 ℃ for 30min to obtain the gas diffusion layer of the embodiment.

(preparation of Membrane electrode)

The gas diffusion layers prepared in this example were used on the cathode side and the anode side, and a membrane electrode (active region: 5×5 cm) was prepared by a mature membrane electrode preparation process matching CCM (homemade by national hydrogen technology).

(assembly and test of Fuel cell)

The membrane electrode of this example was assembled into a single cell (5×5 cm).

Example 2

This embodiment is substantially the same as embodiment 1 except that:

in the method for producing the gas diffusion layer, glycerol is used instead of ethylene glycol in step S3.

Example 3

This embodiment is substantially the same as embodiment 1 except that:

in the method for preparing the gas diffusion layer, mannitol is used for replacing glycol in the step S3.

Example 4 (lower limit of the first rare earth oxide cerium oxide loading)

This embodiment is substantially the same as embodiment 1 except that:

in the gas diffusion layer, the loading of the first rare earth oxide on the carbon material layer is 0.2wt%, and the mass ratio of the first rare earth oxide to the second rare earth oxide is 0.625:5.

In the method for producing the gas diffusion layer, ceO is used in step S1 ₂ The amount of (C) was 0.67 parts by weight.

Example 5 (upper limit of first rare earth oxide cerium oxide loading)

This embodiment is substantially the same as embodiment 1 except that:

in the gas diffusion layer, the loading of the first rare earth oxide on the carbon material layer is 5wt%, and the mass ratio of the first rare earth oxide to the second rare earth oxide is 3.1:1.

In the method for producing the gas diffusion layer, ceO is used in step S1 ₂ The amount of (C) was 16.75 parts by weight.

Example 6 (lower limit of cerium nitrate salt content in second microporous layer)

This embodiment is substantially the same as embodiment 1 except that:

in the gas diffusion layer, the mass ratio of the second rare earth oxide to the second conductive agent to the third hydrophobic agent is 2.8:20:11.5; the mass ratio of the first rare earth oxide to the second rare earth oxide is 1:3.5.

In the method for producing the gas diffusion layer, in step S3, the cerium nitrate salt was used in an amount of 2.8 parts by weight.

Example 7 (upper limit of cerium nitrate salt content in second microporous layer)

This embodiment is substantially the same as embodiment 1 except that:

in the gas diffusion layer, the mass ratio of the second rare earth oxide to the second conductive agent to the third hydrophobic agent is 5.6:20:11.5; the mass ratio of the first rare earth oxide to the second rare earth oxide is 1:7.

In the method for producing the gas diffusion layer, in step S3, the cerium nitrate salt is used in an amount of 5.6 parts by weight.

Example 8 (temperature of heat treatment varies)

This embodiment is substantially the same as embodiment 1 except that:

in the method for producing a gas diffusion layer, in step S5, the temperature of the heat treatment is 300 ℃, and the time of the heat treatment is 30 minutes.

Example 9 (base layer is different from second microporous layer radical quencher)

This embodiment is substantially the same as embodiment 1 except that:

in the gas diffusion layer, the first rare earth oxide is La ₂ O ₃ 。

In the method for producing the gas diffusion layer, la is used in step S1 ₂ O ₃ Instead of CeO ₂ A nano powder.

Example 10 (base layer is the same as second microporous layer radical quencher but different from example 1)

This embodiment is substantially the same as embodiment 1 except that:

in the gas diffusion layer, the first rare earth oxide is La ₂ O ₃ The second rare earth oxide is La ₂ O ₃ 。

In the method for producing the gas diffusion layer, la is used in step S1 ₂ O ₃ Instead of CeO ₂ Nano powder, la in step S3 ₂ O ₃ Instead of cerium nitrate.

Comparative example 1

This comparative example is substantially the same as example 1 except that:

step S3, preparing second microporous layer slurry B: firstly, 15 parts by weight of acetylene black, 4 parts by weight of ethylene glycol, 5 parts by weight of single-walled carbon nanotube dispersion liquid (20 wt% of solvent is water and ethanol), 300 parts by weight of water and 5 parts by weight of sodium dodecyl benzene sulfonate are ball-milled for 2 hours at a rotating speed of 1000r/min to form slurry B1, then 11.5 parts by weight of PTFE emulsion (60 wt% of solvent is water; the weights of the two added PTFE emulsions are equal) are added into the slurry B1 twice, and the two are magnetically stirred for 30 minutes respectively at a rotating speed of 300r/min to prepare second microporous layer slurry B.

Comparative example 2

This comparative example is substantially the same as example 1 except that:

in the preparation method of the gas diffusion layer, cerium nitrate salt is replaced by CeO in the step S3 ₂ 。

Comparative example 3

This comparative example is substantially the same as example 1 except that:

in step S1, 1 part by weight of PTEF emulsion (60% by weight, the solvent being water) and 10.6 parts by weight of ultrapure water were mixed by mechanical stirring so that the mass ratio of PTEF emulsion to ultrapure water was 1:10.6;

in step S3, cerium nitrate is replaced with CeO ₂ 。

Comparative example 4 (without heat treatment)

This comparative example is substantially the same as example 1 except that:

the method for producing the gas diffusion layer does not include step S5.

2. Performance testing

1. Test method

(1) Battery performance test

The fuel cells of each example and comparative example were subjected to a cell performance test using a fuel cell test system, and test conditions: cell temperature: t=80 ℃, degree of humidification: rh=40%/40%, backpressure: bp=100 kpa/100kpa, coefficient of excess: sto=1.5/2.0.

(2) Membrane electrode constant current durability test

And measuring the service life change condition of the proton membrane in the fuel cell by a membrane electrode constant current durability test.

The method for testing the constant current durability of the membrane electrode comprises the following steps: 1) The membrane electrode samples (5×5 cm) were assembled into single cells and mounted on a proton exchange membrane fuel cell test bench. 2) And respectively introducing humidified compressed air and hydrogen with the relative humidity of 40% into the cathode and the anode of the battery, wherein the flow metering ratio is 2.0/1.5, the temperature of the battery is 80 ℃, and the back pressure is 100kPa. 3) The cell was kept running at a current density of 200mA/cm2 and the open circuit run time was recorded. 4) The hydrogen permeation current density was measured and recorded every 20 hours.

(3) Gas diffusion layer permeability test

The gas diffusion layer air permeability test method comprises the following steps: the permeability of the GDL was measured using a GURLEY4340 permeability tester, a low pressure Gurley model was selected, the air gas pressure was set to 100kpa, the air gas volume was set to 100ml, the time to pass through the GDL was recorded, and the data was recorded.

(4) Gas diffusion layer vertical resistance test

The method for testing the vertical resistance of the gas diffusion layer comprises the following steps: and (3) performing GDL vertical resistance test according to the national standard GB/T20042.7-2014 proton exchange membrane fuel cell part 7 carbon paper characteristic test method, and recording data under 1 Mpa.

2. Test results

Fig. 3 is a graph showing comparison of cell performance of comparative example 1 and example 1. As can be seen from the polarization curves of the single cells of FIG. 1, example 1 has significantly better cell performance than comparative example 1, especially at high densities (> 2000 mA/cm) ² ) The battery performance advantage of the mass transfer polarization area example 1 is more obvious, and according to analysis, as the cerium nitrate serving as a precursor of the free radical quencher is added into the second microporous layer slurry B of the example, the cerium nitrate plays a role of a pore forming agent, and the pore size richness of the GDL is increased, so that the water vapor management capability of the GDL is greatly enhanced.

The changes in proton membrane life in the fuel cells of examples and comparative examples are shown in table 1.

Table 1 changes in proton membrane life in the fuel cells of examples and comparative examples

According to table 1:

comparative example 1 and comparative example 1 it can be seen that example 1 was prepared by adding the radical quencher precursor cerium nitrate salt during the constant current durability test of the membrane electrode:

100 After h, example 1 the hydrogen permeation current density was changed from the original 2.68mA/cm ² Rising to 7.9mA/cm ² 195% rise; comparative example 1 the hydrogen permeation current density was changed from the original 2.8mA/cm ² Rising to 15mA/cm ² 436% rise; it can be seen that after 100 h, the hydrogen permeation current density rise of example 1 was reduced by 55% compared to comparative example 1.

220 After h, example 1 the hydrogen permeation current density was changed from the original 2.68mA/cm ² Rising to 23.1mA/cm ² 762% rise; comparative example 1 the hydrogen permeation current density was changed from the original 2.8mA/cm ² Rising to 48mA/cm ² 1614% rise; it can be seen that after 220 h, the hydrogen permeation current density rise of example 1 was reduced by 52.7% compared to comparative example 1.

As can be seen from comparative examples 1 and 2, the gas diffusion layer obtained by using cerium nitrate salt in step S3 of example 1 of the present application compared with the cerium oxide in comparative example 1, was subjected to constant current durability test of the membrane electrode:

100 After h, example 1 the hydrogen permeation current density was changed from the original 2.68mA/cm ² Rising to 7.9mA/cm ² 195% rise; comparative example 2, the hydrogen permeation current density was changed from the original 2.72mA/cm ² Rising to 10.1mA/cm ² 271% rise; it can be seen that after 100 h, the hydrogen permeation current density rise of example 1 was reduced by 28% compared to comparative example 2.

220 After h, example 1 the hydrogen permeation current density was changed from the original 2.68mA/cm ² Rising to 23.1mA/cm ² 762% rise; comparative example 2, the hydrogen permeation current density was changed from the original 2.72mA/cm ² Rising to 29.8mA/cm ² 996% rise; it can be seen that after 220 h, the hydrogen permeation current density rise of example 1 was reduced by 30.7% compared to comparative example 2.

As can be seen from comparative examples 1 and 3, the base layer contains the first rare earth oxide and the microporous layer is prepared using cerium oxide salt compared with the gas diffusion layer obtained in comparative example 3, and in the constant current durability test process of the membrane electrode:

100 After h, example 1 the hydrogen permeation current density was changed from the original 2.68mA/cm ² Rising to 7.9mA/cm ² 195% rise; comparative example 3 the hydrogen permeation current density was changed from the original 2.65mA/cm ² Rising to 12.3mA/cm ² 364% rise; it can be seen that after 100 h, the hydrogen permeation current density rise of example 1 was reduced by 46.4% compared to comparative example 3.

220 After h, example 1 the hydrogen permeation current density was changed from the original 2.68mA/cm ² Rising to 23.1mA/cm ² 762% rise; comparative example 3 the hydrogen permeation current density was changed from the original 2.65mA/cm ² Rising to 32.5mA/cm ² 1126% rise; it can be seen that after 220 h, the hydrogen permeation current density rise of example 1 was reduced by 32.3% compared to comparative example 3.

As can be seen from comparative examples 1 and 4, the gas diffusion layer prepared by the method of example 1 was compared with the gas diffusion layer prepared by the method of comparative example 4 without heat treatment, in the constant current durability test process of the membrane electrode:

100 After h, example 1 the hydrogen permeation current density was changed from the original 2.68mA/cm ² Rising to 7.9mA/cm ² 195% rise; comparative example 4 the hydrogen permeation current density was changed from the original 2.73mA/cm ² Rising to 19.4mA/cm ² 611% rise; it can be seen that after 100 h, the hydrogen permeation current density rise of example 1 was reduced by 68.1% compared to comparative example 4.

220 After h, example 1 the hydrogen permeation current density was changed from the original 2.68mA/cm ² Rising to 23.1mA/cm ² 762% rise; comparative example 4 the hydrogen permeation current density was changed from the original 2.73mA/cm ² Rising to 55.2mA/cm ² 1922% rise; it can be seen that after 220 h, the hydrogen permeation current density rise of example 1 was reduced by 60.3% compared to comparative example 4.

Therefore, after the gas diffusion layer is prepared by the preparation method of the gas diffusion layer, the hydrogen permeation current density increase value of the proton membrane is greatly reduced, and the service life of the proton membrane is greatly prolonged, so that the service life of the membrane electrode is greatly prolonged.

The gas permeability and contact resistance test results of the gas diffusion layers of examples and comparative examples are shown in table 2.

Table 2 results of gas permeability and contact resistance test of gas diffusion layers of examples and comparative examples

As can be seen from table 2, the gas permeability of the examples is better than that of the comparative examples, because the addition of the radical quencher precursor rare earth salt, the chemical substance acts as a pore former at the same time by heat treatment during the GDL preparation process, and the corresponding gas diffusion layer enhances the gas flux.

From fig. 1 and table 2, it can be seen that there is no tendency for the resistance of GDL to increase after increasing the radical quencher precursor rare earth salt, indicating that the introduction of the chemical has no effect on its internal resistance.

In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present application, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

For purposes of this disclosure, the terms "one embodiment," "some embodiments," "example," "a particular example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

While embodiments of the present application have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the application, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the application.

Claims

1. A gas diffusion layer, comprising:

2. The gas diffusion layer of claim 1, wherein the first rare earth oxide and the second rare earth oxide each comprise at least one of cerium oxide, lanthanum oxide, praseodymium oxide.

3. The gas diffusion layer of claim 1, wherein the first, second, and third hydrophobizing agents each comprise at least one of polytetrafluoroethylene, vinylidene fluoride, and polyvinylidene fluoride;

and/or, the first conductive agent and the second conductive agent each comprise at least one of carbon black, acetylene black, ketjen black, graphite powder, expanded graphite and carbon nanotubes;

and/or the carbon material layer comprises at least one of carbon paper, carbon cloth and carbon black paper;

And/or, the carbon material layer is coiled material.

4. The gas diffusion layer of claim 1, wherein the thickness of the first microporous layer is 20-30 μιη;

and/or the thickness of the second microporous layer is 5-10 μm;

and/or the first microporous layer has an average pore size of 1 to 30 μm;

and/or the second microporous layer has an average pore size of 0.5 to 20 μm;

and/or the loading of the first hydrophobizing agent on the carbon material layer is 5-20wt%;

and/or the loading amount of the first rare earth oxide on the carbon material layer is 0.2-5wt%;

and/or the mass ratio of the first conductive agent to the second hydrophobic agent is 1 (0.1-1);

and/or the mass ratio of the second rare earth oxide, the second conductive agent and the third hydrophobic agent is (0.1-0.35): 1: (0.1-1);

and/or, the mass ratio of the first rare earth oxide to the second rare earth oxide is (0.05-0.5): 1.

5. a method of making a gas diffusion layer comprising:

6. The method according to claim 5, wherein the mass ratio of the first hydrophobizing agent, the first rare earth oxide, and the first solvent in the impregnation liquid is (0.4 to 0.8): (0.01-0.05): (8-14);

and/or, the soaking time is 3-10min;

and/or, the carbon material layer is coiled material;

and/or the temperature of the heat treatment is 350-450 ℃, and the time of the heat treatment is 20-40min;

and/or the first hydrophobizing agent, the second hydrophobizing agent and the third hydrophobizing agent comprise at least one of polytetrafluoroethylene, vinylidene fluoride and polyvinylidene fluoride;

and/or, the first rare earth oxide comprises at least one of cerium oxide, lanthanum oxide and praseodymium oxide;

and/or the rare earth salt comprises at least one of cerium salt, lanthanum salt and praseodymium salt;

and/or the mass ratio of the first rare earth oxide to the rare earth salt is (0.01-0.2): 1, a step of;

and/or the first solvent comprises at least one of water, ethanol and isopropanol.

7. The method of producing a gas diffusion layer according to claim 5, wherein forming the first microporous layer on the surface of the base layer comprises:

and/or forming the second microporous layer on a surface of the first microporous layer on a side of the first composite layer remote from the substrate layer, comprising:

8. The method of producing a gas diffusion layer according to claim 7, wherein the mass ratio of the first conductive agent, the second hydrophobic agent, the second solvent, and the first surfactant is (15-21): (4-8): (150-250): (7-13);

and/or the mass ratio of the rare earth salt, the second conductive agent, the third hydrophobic agent, the third solvent, the fourth solvent and the second surfactant is (3-5): (16-24): (5.5-8.3): (84-124): (160-240): (4-6);

And/or the second solvent comprises at least one of water, isopropanol, n-propanol, ethanol and n-butanol;

and/or the first surfactant comprises at least one of Triton-X100, tween 60, polyethylene glycol isooctylphenyl ether and fatty alcohol polyoxyethylene ether;

and/or, the third solvent and the fourth solvent comprise at least one of glycol, glycerol, mannitol and water;

and/or the second surfactant comprises at least one of sodium dodecyl benzene sulfonate, polyvinyl alcohol and polyacrylic acid;

and/or the temperature of the first drying and the second drying is 70-90 ℃, and the time of the first drying and the second drying is 5-15min;

and/or the temperature of the third drying is 200-300 ℃, and the time of the third drying is 10-20min;

and/or the first coating and the second coating are performed by slit extrusion coating or doctor blade coating.

9. A membrane electrode comprising a gas diffusion layer according to any one of claims 1 to 4 or a gas diffusion layer produced by a method of producing a gas diffusion layer according to any one of claims 5 to 8.

10. A fuel cell comprising the membrane electrode according to claim 9.