JP7795285B2 - Carrier material and its manufacturing method - Google Patents

Description

This application claims priority to Chinese patent application No. 202410874263.9 filed on June 27, 2024, and Chinese patent application No. 202311295382.0 filed on September 28, 2023, the entire contents of which are incorporated herein by reference.

This application relates to the technical field of fuel cells, and in particular to carrier materials and methods for manufacturing the same.

Membrane electrodes are the core component in fuel cells, and the catalyst in the membrane electrode can convert chemical energy into electrical energy. The three components - gas, electrons, and protons - undergo an electrochemical reaction on the catalyst surface to produce water, which supplies energy to the connected load device. The membrane electrode is provided with a carrier material that supports the catalyst, and the carrier material provides continuous transmission channels for protons, reactant gases, and water for the electrochemical reaction.

The fine particles of the carrier material are often configured as a porous structure so that the carrier material has a large specific surface area, which provides more attachment sites for the precious metal particles in the catalyst and also provides reaction sites for the catalytic reaction.

The embodiments of this application provide a carrier material and a method for manufacturing the same to solve the problem of high mass transfer resistance in existing membrane electrodes.

The present application is directed to
1. A method for producing a carrier material, comprising:
Dispersing a template agent in a metal salt mixture solution to obtain a first product at a specific concentration;
low-temperature vacuum drying the first product to obtain a second product;
mixing an organic carbon source with the second product to obtain a third product;
performing a first heat treatment on the third product under vacuum or inert gas conditions to obtain a fourth product;
washing the fourth product with an acid pickling solution and drying to obtain a fifth product;
and performing a second heat treatment on the fifth product to obtain a carrier material;
The fine particles of the carrier material are configured to have a plurality of pores and a plurality of cavities, the pores being in communication with the exterior of the fine particles, and the cavities being isolated from the exterior of the fine particles;
When the ratio of the mass of the carrier material to the total volume of the pores is defined as the pore characteristic value, and the ratio of the mass of the carrier material to the total volume of the cavities is defined as the cavity characteristic value, the pore characteristic value of the carrier material is smaller than the cavity characteristic value of the carrier material;
It is realized to provide a method for manufacturing a carrier material.

The carrier material manufacturing method provided by the above-mentioned embodiment of the present application further provides a carrier material manufactured by the above-mentioned carrier material manufacturing method.

Accordingly, embodiments of the present application further provide a membrane electrode for a fuel cell comprising the aforementioned carrier material.

In order to more clearly explain the technical solutions in the embodiments of the present application, the following provides a brief description of the drawings used in the description of the embodiments. Naturally, the drawings in the following description are only a part of the embodiments of the present application, and those skilled in the art can derive other drawings from these drawings without any creative effort.

1 is a structural schematic diagram of a fuel cell provided by an embodiment of the present application; 1 is a schematic diagram of the main steps of the method for manufacturing a carrier material provided by an embodiment of the present application. 1 is a schematic diagram of the microstructure of a catalyst layer provided by an example of the present application. 1 is a structural schematic diagram of the carrier material provided by the embodiment of the present application when combined with catalyst particles; 1 is a schematic diagram of the main steps of a method for manufacturing a catalyst layer provided by an embodiment of the present application. FIG. 1 is a structural schematic diagram of an equivalent circuit for an EIS test. 1 is a schematic diagram of the pore characteristic values and mass transport impedance rules of carrier materials provided by examples of the present application; FIG. 2 is a schematic diagram of the rules for the cavity characteristic value and ECSA retention rate of the carrier material provided by the examples of the present application.

Hereinafter, the technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Of course, the described embodiments are only a portion of the embodiments of the present application, and do not represent all of the embodiments. All other embodiments that can be obtained by those skilled in the art based on the embodiments of the present application without requiring creative effort shall fall within the scope of protection of the present application. It should be understood that the embodiments for implementing the invention described herein are used only to explain and interpret the present application, and are not intended to limit the present application.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention pertains. The terminology used herein in the present specification is for the purpose of describing specific embodiments only and is not intended to be limiting of the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Unless otherwise specified, in this application, directional terms used, such as "up" and "down," generally refer to the up and down of the device in its actual use or working state, specifically the directions shown in the drawings, and "inside" and "outside" refer to positions relative to the outline of the device. In addition, in this description, the term "including" means "including, but not limited to." Terms such as first, second, and third are used merely as symbols and do not necessarily require a number or determine an order.

In this application, "and/or" is used to describe a related relationship between related objects and indicates that three relationships can exist. For example, A and/or B can indicate three cases: A only exists, A and B both exist, or B only exists. Here, A and B can be singular or plural.

As used herein, "at least one" means one or more, and "multiple" means two or more. "One or more," "at least one of the following," or similar expressions, refer to any combination of these terms, including any combination of one or more terms. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can refer to a, b, c, a-b (i.e., a and b), a-c, bc, or a-bc, where a, b, and c may each be singular or plural.

While various embodiments of the present application may be presented in range format, it should be understood that the description in range format is for convenience and brevity only and should not be construed as an inexact limitation on the scope of the present application; therefore, any description of a range as set forth should be considered to specifically disclose all possible subranges and single numerical values within that range. For example, a description of a range of 1 to 6 should be considered to specifically disclose subranges such as 1 to 3, 1 to 4, 1 to 5, 2 to 4, 2 to 6, 3 to 6, etc., as well as single numerical values within that range such as 1, 2, 3, 4, 5, 6, etc., and this applies regardless of the range. Furthermore, whenever a numerical range is presented herein, it is meant to include any numbers (fractional or integer) recited within the stated range.

As shown in FIG. 1, the fuel cell of the present application includes two electrode plates 100 and a membrane electrode disposed between them. The membrane electrode includes a proton membrane 300, a catalyst layer 400, and a diffusion layer 200. The functions, structures, and manufacturing methods of each part of the fuel cell of the present application, other than the catalyst layer 400, are conventional solutions well known to those of ordinary skill in the art and are not the focus of the present application's improvements, so will not be described here.

The technical solution of the present application is as follows:
In a first aspect, as shown in FIG. 2, an embodiment of the present application provides a method for manufacturing a carrier material, which comprises the following main steps:
In S110, the template agent is dispersed in a metal salt mixed solution to obtain a first product with a specific concentration.

Specifically, the template agent includes one or a mixture of two or more of carbon quantum dots, nano-aluminum oxide, nano-silicon oxide, nano-magnesium oxide, nano-calcium oxide, and nano-calcium carbonate.

The metal salts in the metal salt mixture solution include one or more of the following: iron nitrate, chromium nitrate, cobalt nitrate, nickel nitrate, zinc nitrate, magnesium nitrate, iron chloride, cobalt chloride, nickel chloride, zinc chloride, magnesium chloride, iron sulfate, iron sulfate, iron sulfate, zinc sulfate, and magnesium sulfate.

The mixed solvent in the metal salt mixed solution includes a mixture of one or more of isopropyl alcohol, ethylene glycol, n-butanol, N-methylpyrrolidone, and ethanol with distilled water.

More specifically, the volume ratio of distilled water to organic solvent in the mixed solvent is within the range of 1 to 20.

The template agent and metal salt mixture solution is sealed at room temperature and stirred uniformly to obtain a first product. Step S110 serves to obtain a template agent arranged in a specific manner and to uniformly attach the metal salt to the template agent.

The solution concentration of the metal salt mixture solution in step S110 is in the range of 10 mg/mL to 100 mg/mL, and as a further option, the concentration is in the range of 20 mg/mL to 50 mg/mL.

The specific concentration of the first product in step S110 is in the range of 10 wt. % to 50 wt. %, and as a further option, the concentration is in the range of 20 wt. % to 40 wt. %.

In S120, the first product is vacuum dried at low temperature to obtain a second product.

Specifically, the second product is a template metal salt mixture.

The temperature for low-temperature vacuum drying ranges from -40°C to 10°C, and as a further option, the temperature ranges from -30°C to -10°C.

In S130, the organic carbon source is mixed with the second product to obtain a third product.

Specifically, the organic carbon source includes one or more of substances such as asphalt, sugar, heavy oil, fatty acid, polyvinyl alcohol, polyamide, epoxy resin, phenolic resin, organic salt, and derivatives thereof.

More specifically, the mass ratio of the organic carbon source to the second product is 0.1 to 3.

Step S130 serves to achieve mixing with the organic carbon source without destroying the template agent's arrangement.

In S140, the third product is subjected to a first heat treatment under vacuum or inert gas conditions to obtain a fourth product.

Specifically, the first heat treatment in step S140 is performed under vacuum or inert gas conditions, and the inert gas includes one or both of argon gas and nitrogen gas.

More specifically, the temperature increase rate for the first heat treatment in step S140 is between 1°C/min and 20°C/min, and the heat treatment temperature is between 200°C and 1000°C.

As a further option, the heating rate for the first heat treatment is between 5°C/min and 10°C/min, and the heat treatment temperature is between 500°C and 700°C.

Step S140 serves to carbonize the organic carbon source to obtain a specific pore or cavity structure, where the pores are derived from the pore-forming effect of the template agent and the catalytic action of the metal salt, and the carbon source itself also forms pores or cavities during the shrinkage carbonization process. The fourth product is a carbon powder with a specific pore or cavity structure.

Step S140 serves to allow the template agent and metal salt to work together to form a product with a specific pore or cavity structure.

In S150, the fourth product is washed with pickling solution and dried to obtain a fifth product.

Specifically, the pickling solution contains one or more of hydrochloric acid, nitric acid, perchloric acid, sulfuric acid, acetic acid, and hydrofluoric acid.

The concentration of the substance mass of the pickling solution is in the range of 0.2 mol/L to 5 mol/L, and as a further option, the concentration of the substance mass of the pickling solution is in the range of 0.5 mol/L to 2 mol/L.

Step S150 aims to remove most of the metal salts and template agent.

In S160, the fifth product is subjected to a second heat treatment to obtain a carrier material.

The purpose of S160 is for some pores to close and form cavities during the graphitization process, and for metal salts remaining in some of the cavities to react with carbon to form a pore structure, while the metals exert varying degrees of graphitization catalytic function to enhance the degree of graphitization of the material.

Specifically, step S160 mainly includes the following steps.
In S161, the fifth product is subjected to a high-temperature heat treatment in an inert atmosphere to obtain an intermediate product.

Specifically, the inert atmosphere gas contains one or both of argon gas and nitrogen gas.

The temperature rise rate for the high-temperature heat treatment in step S161 is between 1°C/min and 20°C/min, and the heat treatment temperature is between 1000°C and 2600°C.

As a further option, the heating rate of the high-temperature heat treatment is in the range of 5°C/min to 10°C/min, and the heat treatment temperature is in the range of 1400°C to 1900°C.

In S162, the intermediate product is cooled.

Specifically, the cooling process is carried out by allowing the material to cool naturally to room temperature.

In S163, the intermediate product after the cooling treatment is subjected to a medium-temperature heat treatment in an oxidizing atmosphere, and after cooling, a carrier material is obtained.

Specifically, the oxidizing atmosphere gas includes one or more of carbon dioxide, an oxidizing atmosphere containing oxygen (air, water vapor, oxygen gas, ozone, etc.), and ammonia.

The temperature rise rate for the medium-temperature heat treatment in step S163 is between 1°C/min and 20°C/min, and the heat treatment temperature is between 150°C and 500°C.

As a further option, the temperature ramp rate for the medium-temperature heat treatment is between 1°C/min and 15°C/min, and the heat treatment temperature is between 200°C and 400°C.

The above heat treatment method of step S160 is adopted to control the pore characteristic value and cavity characteristic value of the carrier material 410.

High-temperature heat treatment increases the crystallinity of carbon materials; the higher the crystallinity, the better the corrosion resistance and the smaller the specific surface area. At high temperatures, carbon materials undergo a structural restructuring, with the graphite microcrystalline layer on the surface polymerizing and rearranging during this process, and the pore structure (pore diameter, pore volume, etc.) changing during this process, with some of the pores becoming cavities. At the same time, the high temperature releases some of the metal salts, forming new pore and cavity structures.

Medium-temperature heat treatment is an oxidation modification process performed on materials. This process reduces the material's fixed carbon content and increases the elemental content of oxygen, hydrogen, and nitrogen (depending on the synthesis conditions). This increases the content of the corresponding groups, making it easier for precious metal particles to adhere. It also increases the interconnectivity of the pore structure, converting some of the cavity structure into a pore structure.

In a second aspect, as shown in Figures 3 and 4, an embodiment of the present application provides a carrier material 410, which primarily provides a carrier for catalyst particles 420 (noble metal particles, e.g., Pt nanoparticles) in the catalyst layer 400, and the carrier material 410 is a powder material.

Specifically, the fine particles of the carrier material 410 of the present application are configured to have multiple pores and multiple cavities, the pores are connected to the outside of the fine particles, and the cavities are isolated from the outside of the fine particles. If the ratio of the mass of the carrier material 410 to the total volume of the pores is defined as the pore characteristic value, and the ratio of the mass of the carrier material 410 to the total volume of the cavities is defined as the cavity characteristic value, the pore characteristic value of the carrier material 410 is smaller than the cavity characteristic value of the carrier material 410.

As an optional solution, the carrier material 410 comprises at least a carbon material.

The mass transfer capacity of carbon materials is related to the size and type of pores. Typically, when the pore diameter is 2 nm or larger, the space can communicate with the outside during the mass transfer process, making it easier for continuous and stable reactions to occur. Furthermore, the water produced can be discharged in a timely manner, ensuring the continuous progress of the reaction. These spaces are called pores, and include interconnected pores, through pores, and blind pores. The surface area of these pores can be detected and analyzed using gas adsorption methods.

In addition to these pores, there may be several enclosed spaces within the fine particles of the carrier material 410. These pores have small diameters (≦2 nm) or are not connected to the outer surface, making them impermeable to fluids. These spaces cannot be effectively measured using measurement methods such as gas adsorption and mercury porosimetry, making them difficult to use as locations for continuous and stable electrochemical reactions under working conditions.

Therefore, pores in the microparticles of the carrier material of the present application have a pore diameter of 2 nm or less, which makes it difficult for fluids to enter. Therefore, pores with a pore diameter of 2 nm or less can also be classified as cavities as defined in the present application. In other words, the phrase "isolated from the outside of the microparticles of the carrier material 410" used in the present application is based on the criterion that liquids cannot effectively flow into them. In other words, the "cavity" used in the present application, "isolated from the outside of the microparticles of the carrier material 410," includes not only a sealed space that is completely disconnected from the outside of the microparticles of the carrier material 410, but also pores (non-sealed spaces) that are connected to the outside of the microparticles of the carrier material 410 but have a pore diameter of 2 nm or less.

The carbon material's large pore characteristic value significantly improves mass transfer capacity and reduces mass transfer resistance under high current density operating conditions, and the appropriate pore structure delays phenomena such as catalyst flooding and clogging of gas diffusion pore channels. Furthermore, carrier materials 410 with high cavity characteristic values exhibit higher carrier material 410 durability under operating conditions such as start-up and shutdown.

Such porous carbon materials with optimized pores and cavities can also be used in other areas related to mass and charge transport processes, such as lithium batteries, sodium ion batteries, and drug delivery.

In some embodiments, the ratio of the pore characteristic value to the cavity characteristic value of the carrier material 410 is in the range of 0.005 to 0.045.

In some embodiments, the ratio of the pore characteristic value to the cavity characteristic value of the carrier material 410 is a value in the range of 0.0102 to 0.0163, more specifically, a value in the range of 0.014 to 0.015, or 0.0145 to 0.0148.

In some embodiments, the ratio of the pore characteristic value to the cavity characteristic value of the carrier material 410 is a value in the range of 0.0232 to 0.0384, or more specifically, a value in the range of 0.020 to 0.030, or 0.025 to 0.028.

In some embodiments, the ratio of the pore characteristic value to the cavity characteristic value of the carrier material 410 is a value in the range of 0.0090 to 0.0180, more specifically, a value in the range of 0.012 to 0.013, or 0.0125 to 0.0129.

In some embodiments, the carrier material 410 may have a pore characteristic value ranging from 0.250 g/cm ³ to 0.450 g/cm ³ .

In some embodiments, the carrier material 410 may have a pore characteristic value ranging from 0.260 g/cm ³ to 0.350 g/cm ³ .

In some embodiments, the carrier material 410 may have a cavity characteristic value in the range of 10.00 g/cm ³ to 50.00 g/cm ³ .

In some embodiments, the carrier material 410 may have a cavity characteristic value in the range of 20.00 g/cm ³ to 40.00 g/cm ³ .

In some embodiments, the pore characteristic value of the carrier material 410 may be a value in the range of 0.256 g/cm ³ to 0.298 g/cm ³ , and simultaneously the cavity characteristic value of the carrier material 410 may be a value in the range of 18.306 g/cm ³ to 24.902 g/cm ³ .

In some embodiments, the pore characteristic value of the carrier material 410 may be a value in the range of 0.375 g/cm ³ to 0.418 g/cm ³ , and simultaneously the cavity characteristic value of the carrier material 410 may be a value in the range of 10.897 g/cm ³ to 16.105 g/cm ³ .

In some embodiments, the pore characteristic value of the carrier material 410 may be a value in the range of 0.260 g/cm ³ to 0.350 g/cm ³ , and simultaneously the cavity characteristic value of the carrier material 410 may be a value in the range of 19.306 g/cm ³ to 30.026 g/cm ³ .

In some embodiments, the carrier material 410 may have a pore characteristic value of 0.284, 0.319, or 0.399.

In some embodiments, the cavity characteristic value of the carrier material 410 may be 14.298, 19.306, or 24.902.

In some embodiments, the specific surface area of the carrier material 410 may be in the range of 400 m ² /g to 1500 m ² /g. As a further option, the specific surface area of the carrier material 410 may be in the range of 500 m ² /g to 1100 m ² /g.

In some embodiments, the particle size of the carrier material 410 may be in the range of 100 nm to 2 μm. As a further option, the particle size of the carrier material 410 may be in the range of 200 nm to 800 nm.

In some embodiments, the compaction density of the carrier material 410 may be a value in the range of 0.05 g/mL to 0.80 g/mL. As a further option, the compaction density of the carrier material 410 may be a value in the range of 0.10 g/mL to 0.50 g/mL.

In some embodiments, the conductivity of the carrier material 410 may be in the range of 6.4 S/cm to 26.5 S/cm.

In some embodiments, the fixed carbon content of the carrier material 410 may be in the range of 84.5% to 97.2%.

In order to quantitatively express the structural characteristics of pores that contribute to the occurrence of mass transfer reactions in carbon materials, in this application, pore characteristic values are used.
is set as a characteristic value that can represent the content of pores in which the mass transfer reaction can occur stably in the carrier material, and the cavity characteristic value
are set as characteristic values that can represent the content of cavities in which the mass transfer reaction cannot occur stably in the carrier material, and the derivation formulas thereof are as follows:
In Formula 1,
refers to the theoretical true density of ideal single crystal graphite (which is 2.266 g/ ^cm3 ),
refers to the mass of ideal single crystal graphite,
is the mass
shows the volume of ideal single crystal graphite.
In Equation 2,
refers to the true density of the carrier material;
refers to the mass of the carrier material;
is the mass
_V refers to the volume of ideal single crystal graphite with a mass of
, where σ is the cavity volume of the carrier material.
In Equation 3,
refers to the compaction density of the carrier material;
refers to the mass of the carrier material;
is the mass
refers to the volume of ideal single crystal graphite,
is the mass
refers to the pore volume of the carrier material,
is the mass
, where σ is the cavity volume of the carrier material.

Among them, the carrier materials with specific pore structures are as shown in Formulas 4 and 5.

Therefore, the pore characteristic value is
, cavity characteristic value
is as shown in Equations 6 and 7.

The calculation formulas for the pore characteristic value and cavity characteristic value in this application have been explained above, so the true density of the carrier material is shown below.
, denotes the compaction density of the carrier material
, and the theoretical true density of ideal single crystal graphite
The pore characteristic value and cavity characteristic value in the present application can be calculated by the above.

In a third aspect, as shown in FIG. 5, an embodiment of the present application provides a method for manufacturing a catalyst layer using the above carrier material, including the following steps:
In S210, a certain amount of precious metal precursor is taken and dissolved in an organic solvent, and a certain amount of carrier material 410 is added thereto under vigorous stirring, and the mixture is sealed and stirred uniformly, and then dried to obtain a sixth product.

Specifically, the organic solvent in S210 includes one or more of ethanol, isopropyl alcohol, ethylene glycol, and n-butanol.

The precious metal precursor in step S210 includes one or more of chloroplatinic acid, potassium chloroplatinate, potassium tetrachloroplatinate(II), platinum dichloride, platinum tetrachloride, tetraammineplatinum(II) chloride monohydrate, and bis(acetylacetonato)platinum.

The mass concentration of the precious metal precursor in step S210 is in the range of 0.1 mol/L to 5 mol/L, and as a further option, in the range of 1 mol/L to 2 mol/L.

The rotation speed for vigorous stirring in S210 is 300 to 1000 rpm/min.

In S220, the sixth product is taken and subjected to heating and reduction in a mixed gas atmosphere of _H2 and an inert gas at a specific concentration to obtain a carbon powder (seventh product) having a specific precious metal content.

Specifically, the specific concentration of _H2 in S220 may be a mixed gas of _H2 and Ar or _H2 and _N2 in any ratio.

The heating rate of the thermal reduction in step S220 is between 1°C/min and 20°C/min, and optionally between 5°C/min and 10°C/min, and the thermal reduction temperature is between 200°C and 900°C, and optionally between 300°C and 400°C.

In S230, a certain amount of the seventh product is taken, washed with pickling solution, and dried to obtain a platinum-containing catalyst.

Specifically, the pickling solution in S230 contains one or more of nitric acid, perchloric acid, and acetic acid.

The substance concentration of the pickling solution in S230 is in the range of 0.2 mol/L to 5 mol/L, and as a further option, in the range of 0.5 mol/L to 2 mol/L.

It can be understood that the mass transfer capacity of the catalyst layer 400 of a fuel cell is related to the size and type of pores in the carbon material. During the mass transfer process, the reaction occurs continuously and stably in the cavities and pore channels that are connected to the outside, and the generated water can be discharged in a timely manner to ensure the continuous progress of the reaction. The organic biomass precursor that has been treated at high temperatures is thermally decomposed and carbonized, and the corresponding pore structure is formed under the action of the template agent. Under the catalytic action of the metal salt, the molecules of the graphitic microcrystalline layer on the surface polymerize and rearrange, continuously improving the degree of regularity and order, tending to graphitize, and finally forming a porous carbon structure that has been graphitized to a certain extent.

Specifically, the pore characteristic value
is a characteristic value that can represent the content of pores in the carrier material where a mass transfer reaction can occur stably, and the pore characteristic value
The smaller the value, the stronger the carrier material's ability to stably generate mass transfer reactions, the easier it is to discharge water produced by reactions in the catalyst layer 400, and the lower the risk of flooding the reaction site, which will prevent oxygen from entering.

In addition to these pores, the carrier material 410 contains several cavities that are not connected to the outer surface and are impermeable to fluids. These cavities do not directly affect the performance of the catalyst layer 400 in the early stages of the electrochemical reaction, and cannot be detected or analyzed by gas adsorption methods. However, under high-potential operating conditions such as during start-up and shutdown, the presence of these cavities exacerbates corrosion of the carrier material.

Specifically, the cavity characteristic value
is used as a characteristic parameter that can express the structure in question to evaluate the state of a cavity that is not connected to the outer surface and cannot be penetrated by a fluid, and the cavity characteristic value
The larger the value, the fewer the cavity structure, and the more corrosion-resistant components with a high degree of graphitization, and the stronger the corrosion resistance of the carrier material under high-potential working conditions such as start-up and shutdown.

In a fourth aspect, by using the above-mentioned carrier material in a membrane electrode of a fuel cell, the membrane electrode has excellent mass transfer capabilities.

The present application has the advantageous effect of providing a carrier material and a manufacturing method thereof that improves the mass transfer resistance of a membrane electrode made of the carrier material by controlling the pore characteristic values and cavity characteristic values.

The technical solution of this application will be further explained below with reference to specific examples.

Example 1
(1) Carbon quantum dots were dispersed in a 10 mg/mL solution of iron nitrate in isopropyl alcohol, and the mixture was stirred in a sealed container at room temperature to obtain a 10 wt. % template agent mixture (Product 1). The volume ratio of water to isopropyl alcohol in the iron nitrate in isopropyl alcohol mixture was 0.5.

(2) The first product was collected and dried in a vacuum at low temperature of -40°C to obtain a template metal salt mixture (second product).

(3) Heavy oil was added to the second product, and the mixture was stirred in a sealed container at room temperature to obtain a third product. Here, the mass ratio of heavy oil to the second product was 0.1.

(4) Using an HF-Kejing KSL-1700L box furnace, the third product was subjected to a first heat treatment under nitrogen conditions. The heating rate for the first heat treatment was 1°C/min, the temperature was raised to 200°C, the product was cooled, and the product was removed to obtain the fourth product.

(5) The fourth product was placed in a 0.2 mol/L hydrochloric acid solution for acid washing and purification, followed by filtration and drying to obtain carbon powder (fifth product).

(6) The fifth product was subjected to a second heat treatment (high-temperature heat treatment) in an argon atmosphere using a FULLAD graphitization furnace. The temperature increase rate for the high-temperature heat treatment was 10°C/min, the temperature was 1600°C, and the product was allowed to cool naturally to room temperature. Then, a medium-temperature heat treatment was performed in a carbon dioxide atmosphere, the temperature increase rate for the medium-temperature heat treatment was 10°C/min, the temperature was 200°C, and the product was allowed to cool to obtain a carrier material. This carrier material in this example was defined as C1.

(7) The carrier material was placed in a 1 mol/L ethanol solution of chloroplatinic acid at a rotation speed of 500 rpm/min, sealed, stirred uniformly, and dried to obtain Product 6.

(8) The sixth product was heated and reduced in a _H2 (20% Ar) gas atmosphere to obtain a seventh product. A BONA tube furnace was used, and the heating rate for the thermal reduction was set to 5°C/min, and the temperature was set to 200°C.

(9) The seventh product was placed in a 1 mol/L hydrochloric acid solution, washed with acid, purified, filtered, and dried to obtain a platinum-containing catalyst. This platinum-containing catalyst was defined as C1-cat in this example.

Examples 2 to 10
Examples 2 to 10 differ from Example 1 in the mass concentration of the template agent mixture (first product) obtained in (1).
Table 1 shows the mass concentrations of the template agent mixtures (first products) in Examples 2 to 10.

Examples 11 to 19
Examples 11 to 19 differ from Example 1 in the concentration of the iron nitrate isopropyl alcohol mixed solution in (1).
Table 2 shows the concentrations of iron nitrate in isopropyl alcohol solutions.

The test method used in this application is described below.

1) Test method for specific surface area of carbon material:
At a constant low temperature, an ASAP2460 Micromeritics specific surface area tester was used to measure the gas adsorption amount on the solid surface at different relative pressures, and then the adsorption amount of the monolayer of the sample was calculated based on the Brunauer-Emmett-Teller adsorption theory and its formula (BET formula), and the specific surface area SA of the material was calculated.

2) Test method for pore and cavity characteristics:
Carrier materials were randomly selected and measured using a Pentapyc™ 5200E true density tester.
was measured by a GeoPyc-1365 Micromeritics tap density tester.
(The pressure is 1 MPa, which is the same as the pressure used in the production of membrane electrodes.)
(2.266 g/ ^cm³ ) is the pore characteristic value of the carbon material.
, cavity characteristic value
obtained.

3) Test method for particle size of carrier material:
The particle size of the carrier material was tested using a Malvern 3000 laser particle sizer. The intensity distribution of scattered light generated in each direction by particles depends on the particle size, with larger particles having a smaller scattering angle and smaller particles having a larger scattering angle, so the particle size distribution of the particles was obtained using the intensity distribution of scattered light from laser diffraction.

4) Test method for platinum content in catalyst:
A certain amount of catalyst sample was dissolved in aqua regia, filtered and volumized, and tested for elemental content ICP-Pt by ICP spectrometer.

5) Test method for electrochemically active area and retention rate of catalyst:
The performance of the catalysts prepared using the carrier materials was tested using a three-electrode system. A certain amount of catalyst was weighed out and sequentially added with 5% Nafion solution, deionized water, and isopropyl alcohol. The slurry was uniformly mixed using ultrasound. The dispersed slurry was then uniformly applied to the surface of a disk electrode to achieve a catalyst loading of 20 μg/ ^cm2 to 50 μg/ ^cm2 . After drying, the working electrode was formed. The working electrode, reference electrode, and counter electrode were placed in an electrolytic cell to form a three-electrode system. Here, the reference electrode was a RHE reversible hydrogen electrode, the counter electrode was a large-area Pt sheet, and the electrolyte was a saturated 0.1 M _HClO4 solution.

A cyclic voltammetry curve test was conducted. First, the catalyst was activated at a scan rate of 20 mV/s. After the hydrogen desorption peak area stopped increasing, the catalyst was scanned 10 times at a scan rate of 20 mV/s, with the potential scan range being 1.0 V to 1.5 V vs. RHE. After stabilization, the cyclic voltammetry curve was taken, and the hydrogen desorption peak (0.05 V to 0.4 V vs. RHE) was integrated to obtain the area S, from which the electrochemically active area ECSA was calculated using Equation 8.
In Equation 8,
refers to the electrochemically active area, in square meters per gram (m/g);
refers to the integrated area of the hydrogen desorption region, and has units of amperes*volts (A*V);
refers to the oxidation adsorption charge constant of adsorbed hydrogen on a smooth Pt surface, which is 0.21 millicoulombs per square centimeter (0.21 mC/cm ² );
refers to the scan rate, in millivolts per second (mV/s),
refers to the mass of Pt in the electrode, in grams (g).

The test was cycled 10,000 times within the range of 1.0 V to 1.5 V vs. RHE, and the retention of the electrochemically active area of the working electrode before and after the cyclic voltammetry test was recorded.

6) Test method for mass transport impedance of catalyst layer:
A battery test bench was used to test the performance of a single cell whose catalyst layer was made of carbon material. The catalyst loading of the anode of the membrane electrode used was 0.2 mg/ ^cm² , and the catalyst loading of the cathode was 0.4 mg/ ^cm² . After sufficient activation, an impedance test was performed under the conditions of a battery operating temperature of 80°C, humidity of 100 RH%, and battery back pressure of 150 kPa/150 kPa. A load was applied so that the current reached 2 A/ ^cm² , and a 10% disturbance current was applied in current control mode, with a frequency of 10,000 Hz to 0.5 Hz.

As shown in Figure 6, the Nyquist plot obtained from the EIS test was fitted by the equivalent circuit shown in Figure 6, in which the mass transport impedance is represented by a finite Warburg impedance element.

The detection results for SA, fixed carbon, conductivity, pore characteristic value, cavity characteristic value, ideal density, true density, and compaction density are shown in Table 3.

The results of the detection of ICP-Pt, ECSA, ECSA retention, and mass transport impedance are shown in Table 4.

As can be seen from the detection results in Examples 1 to 19 and Tables 3 to 4, the pores in the carrier material are derived from both pore formation by the template agent and pore formation by the catalytic action of metal salts. In the examples of the present application, the mass concentration of the template agent mixture and the concentration of the metal salt mixture were mainly changed, and the two cooperated to contribute to pore/cavity formation. The resulting carrier materials had pore characteristic values of 0.15 to 0.52 g/cm ³ , cavity characteristic values of approximately 7 to 60 g/cm ³ , ICP-Pt of 46.2 to 49.2 wt. %, ECSA of 66.7 to 96.2 g/cm ³ , ECSA retention of 62.54 to 83.84%, and mass transport impedance of 0.553 to 1.131 2 A/cm ² @ Ω cm ² . By selecting pore characteristic values and cavity characteristic values suitable for this application based on the predetermined target ECSA retention rate and mass transport impedance, it is possible to express the mass transport capacity of the membrane electrode using the pore characteristic values and cavity characteristic values.

As can be seen from the detection results of Examples 6 and 9 and Table 4, the specific surface area of Example 6 was 1459.56 m2/g, the ECSA was 79.1 ^m2 /g, the ECSA retention was 62.54%, and the mass transport impedance was ^{1.131 Ω.cm2} @ 2A/ ^cm2 , while the specific surface area of Example 9 was 1502.91 m2/g, the ECSA was 89.5 ^m2 /g, the ECSA retention was 83.84%, and the mass transport impedance was 0.637 Ω.cm2 @ 2A/ ^cm2. Although Examples 6 and 9 are carrier materials with similar specific surface areas, there are significant differences in the ECSA retention and mass transport impedance, which indicates a large difference in the mass transport of membrane electrodes made of the carrier materials.

By changing the concentration of the template agent mixture under the same metal salt conditions, the manufactured carrier material contributes to more uniform adhesion of the metal salt to the template, ensuring sufficient contact with the carbon source during the first heat treatment process and forming pores or cavities in which a certain amount of template agent is interconnected or adjacent to each other. If the mass concentration of the template agent mixture is too high, the metal salt may not be dispersed uniformly in the template, resulting in the above-mentioned pore formation process being unable to be achieved. If the metal salt acts directly on the carbon source without the aid of a template agent, a large number of disconnected micropores and cavities will be formed.

By changing the concentration of the metal salt mixed solution under the same template agent concentration, the metal salt acts as a graphitization catalyst during the second heat treatment process, contributing to improving the stability of the mass transfer process. The remaining metal salt also acts as a pore-forming agent, connecting several fine micropores to form pores, reducing the proportion of cavity structures and increasing the cavity characteristic value, which contributes to improving the degree of graphitization. This carrier material has stronger corrosion resistance when used under high-voltage operating conditions such as start-up and shutdown.

As can be seen from the detection results of Examples 1 to 19, Table 4, and Figure 7, there is a certain rule between the pore characteristic value and mass transport impedance of the carrier material produced by the present application. As the pore characteristic value increases, the mass transport impedance also tends to increase accordingly. However, due to the existence of variations in the change process, further screening of the pore characteristic value is performed. When the pore characteristic value is in the range of 0.25 to 0.45 g/ ^cm3 , a carrier material with high mass transport impedance can be obtained, and the mass transfer capacity of the membrane electrode is good. On the other hand, when the pore characteristic value exceeds 0.45 g/ ^cm3 , the mass transport impedance increases sharply, causing a rapid decrease in the current density in the membrane electrode polarization curve, which in turn reduces the power density of the membrane electrode. When the pore characteristic value is less than 0.25 g/ ^cm3 , the change in mass transport impedance is not significant enough.

As can be seen from the detection results of Examples 1 to 19, Table 4 and FIG. 8, there is a certain rule between the cavity characteristic value and the ECSA retention rate of the carrier material produced according to the present invention. As the cavity characteristic value increases, the ECSA retention rate tends to increase first and then gradually decrease. Therefore, the preferred range of the cavity characteristic value is 10 to 50 g/ ^cm3 .

In summary, the mass transfer capacity of a membrane electrode is related to the size and type of pores in the carbon material. During the mass transfer process, the reaction occurs continuously and stably in the cavities and pore channels that are connected to the outside, and the generated water can be discharged in a timely manner to ensure the continuous progress of the reaction. After high-temperature treatment, the organic biomass precursor is thermally decomposed and carbonized, and the corresponding pore structure is formed under the action of the template agent. Under the catalytic action of the metal salt, the molecules in the graphitic microcrystalline layer on the surface polymerize and rearrange, continuously improving their regularity and order, and tending to graphitize. Finally, a porous carbon structure with a certain degree of graphitization is formed, resulting in a membrane electrode with excellent mass transfer capacity.

The above provides a detailed description of the carrier material and its manufacturing method provided by the examples of the present application. While specific examples are used in the text to explain the principles and embodiments of the present application, the explanations of the above examples are intended to be used only to understand the method and gist of the present application. Furthermore, those skilled in the art will recognize that the gist of the present application may lead to changes in the mode for implementing the invention and the scope of application. In summary, the contents of this specification should not be construed as limiting the present application.

100: Electrode plate 200: Diffusion layer 300: Proton membrane 400: Catalyst layer 410: Carrier material 420: Catalyst particles

Claims (12)

1. A method for producing a carrier material, comprising:
Dispersing a template agent in a metal salt mixture solution to obtain a first product at a specific concentration;
low-temperature vacuum drying the first product to obtain a second product;
mixing an organic carbon source with the second product to obtain a third product;
performing a first heat treatment on the third product under vacuum or inert gas conditions to obtain a fourth product;
washing the fourth product with an acid pickling solution and drying to obtain a fifth product;
and performing a second heat treatment on the fifth product to obtain the carrier material;
the template agent comprises one or more of carbon quantum dots, nano aluminum oxide, nano silicon oxide, nano magnesium oxide, nano calcium oxide, and nano calcium carbonate;
The fine particles of the carrier material are configured to have a plurality of pores and a plurality of cavities, the pores being in communication with the outside of the fine particles, and the cavities being isolated from the outside of the fine particles;
When the ratio of the mass of the carrier material to the total volume of the pores is defined as a pore characteristic value and the ratio of the mass of the carrier material to the total volume of the cavities is defined as a cavity characteristic value, the pore characteristic value of the carrier material is smaller than the cavity characteristic value of the carrier material.
A method for producing a carrier material. the pore characteristic value of the carrier material includes a value in the range of 0.250 g/cm ³ to 0.450 g/cm ³ and/or the cavity characteristic value of the carrier material includes a value in the range of 10.00 g/cm ³ to 50.00 g/cm ³ ;
A method for producing the carrier material of claim 1 . the metal salt in the metal salt mixed solution includes one or more of iron nitrate, chromium nitrate, cobalt nitrate, nickel nitrate, zinc nitrate, magnesium nitrate, iron chloride, cobalt chloride, nickel chloride, zinc chloride, magnesium chloride, iron sulfate, iron sulfate, iron sulfate, zinc sulfate, and magnesium sulfate;
The mixed solvent in the metal salt mixed solution includes a mixture of one or more of isopropyl alcohol, ethylene glycol, n-butanol, N-methylpyrrolidone, and ethanol with distilled water;
The solution concentration of the metal salt mixed solution is in the range of 10 mg/mL to 100 mg/mL, and the concentration of the first product of the specific concentration is in the range of 10 wt. % to 50 wt. %.
A method for producing the carrier material of claim 1 . the organic carbon source comprises one or more of asphalt, sugar, heavy oil, fatty acid, polyvinyl alcohol, polyamide, epoxy resin, phenolic resin, organic salt, and derivatives thereof;
In the step of mixing the organic carbon source with the second product to obtain a third product, the mass ratio of the organic carbon source to the second product comprises a value in the range of 0.1 to 3;
A method for producing the carrier material of claim 1 . In the step of performing a first heat treatment on the third product under vacuum or inert gas conditions to obtain a fourth product, the temperature rise rate of the first heat treatment includes a value within a range of 1°C/min to 20°C/min, and the heat treatment temperature includes a value within a range of 200°C to 1000°C.
A method for producing the carrier material of claim 1 . the pickling solution contains one or more of hydrochloric acid, nitric acid, perchloric acid, sulfuric acid, acetic acid, and hydrofluoric acid;
The substance concentration of the pickling solution includes a value in the range of 0.2 mol/L to 5 mol/L;
A method for producing the carrier material of claim 1 . The step of subjecting the fifth product to a second heat treatment to obtain the carrier material includes:
heat-treating the fifth product at a high temperature in an inert atmosphere to obtain an intermediate product;
cooling the intermediate product;
and subjecting the cooled intermediate product to a medium-temperature heat treatment in an oxidizing atmosphere to obtain the carrier material.
The temperature rise rate of the high-temperature heat treatment includes a value in the range of 1°C/min to 15°C/min, and the heat treatment temperature includes a value in the range of 1000°C to 3000°C, and the temperature rise rate of the medium-temperature heat treatment includes a value in the range of 1°C/min to 15°C/min, and the heat treatment temperature includes a value in the range of 100°C to 600°C.
A method for producing the carrier material according to any one of claims 1 to 6. A carrier material comprising:
The fine particles of the carrier material are configured to have a plurality of pores and a plurality of cavities, the pores being in communication with the outside of the fine particles, and the cavities being isolated from the outside of the fine particles;
The ratio of the mass of the carrier material to the total volume of the pores is defined as a pore characteristic value;
When the ratio of the mass of the carrier material to the total volume of the cavity is defined as a cavity characteristic value,
The pore characteristic value of the carrier material is smaller than the cavity characteristic value of the carrier material.
Carrier material. the pore characteristic value of the carrier material includes a value in the range of 0.250 g/cm ³ to 0.450 g/cm ³ and/or the cavity characteristic value of the carrier material includes a value in the range of 10.00 g/cm ³ to 50.00 g/cm ³ ;
The carrier material of claim 8. the specific surface area of the carrier material comprises a value in the range of 400 m ² /g to 1500 m ² /g;
and/or
The particle size of the carrier material includes values in the range of 100 nm to 2 μm;
and/or
the compaction density of the carrier material comprises a value within the range of 0.05 g/mL to 0.80 g/mL;
the conductivity of the carrier material comprises values in the range of 6.4 S/cm to 26.5 S/cm;
the fixed carbon content of the carrier material includes values within the range of 84.5% to 97.2%;
The carrier material of claim 8. A fuel cell comprising the carrier material described in any one of claims 8 to 10. Use of the carrier material according to any one of claims 8 to 10 in a membrane electrode of a fuel cell.