Proton exchange membrane fuel cell cathode catalyst slurry, cathode catalyst layer, membrane electrode, fuel cell, preparation method and application

Abstract

The invention relates to a proton exchange membrane fuel cell cathode catalyst slurry, a cathode catalyst layer, a membrane electrode, a fuel cell, a preparation method and an application. The cathode catalyst slurry comprises a perfluorinated sulfonic acid resin solution, a cathode additive, a Pt / C catalyst and a first solvent; the cathode additive is selected from one or more of aminated multi-walled carbon nanotubes, carboxylated multi-walled carbon nanotubes, conductive polyaniline, oxidized conductive carbon black, fluorinated conductive carbon black and conductive carbon black; a perfluorosulfonic acid resin solution and a cathode additive are mixed and dispersed in advance, then a Pt / C catalyst and a solvent are added, pre-regulation and control of the form and distribution of the perfluorosulfonic acid resin can be achieved in the obtained cathode catalyst slurry, and an ionomer in the perfluorosulfonic acid resin and an intermolecular acting force of the Pt / C catalyst are combined to form the cathode catalyst slurry. Poisoning of ionomer sulfonic acid groups to platinum is weakened, and accessibility of oxygen to platinum is improved; the membrane electrode has good comprehensive performance in the aspects of conductivity and stability, and the preparation method is simple, convenient and rapid.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a cathode catalyst slurry, a cathode catalyst layer, a membrane electrode, a fuel cell, a preparation method and an application thereof. Background Art

[0002] Proton exchange membrane fuel cell technology is considered to be a new energy technology that is cleaner than lithium secondary battery technology. Proton exchange membrane fuel cells using hydrogen as raw material are also one of the key technologies for hydrogen energy applications. In mainstream technologies, hydrogen fuel cells use membrane electrodes with high platinum-carbon catalyst content, which results in high costs for hydrogen fuel cells, limiting their large-scale application. Summary of the invention

[0003] Based on this, the purpose of the present application includes providing a proton exchange membrane fuel cell cathode catalyst slurry, a cathode catalyst layer, a membrane electrode, a fuel cell, a preparation method and an application.

[0004] The cathode additive is introduced into the cathode catalyst slurry of the proton exchange membrane fuel cell of the present application, and the cathode catalyst is pre-mixed with the perfluorosulfonic acid resin solution, which is beneficial to reduce the poisoning of platinum by the ionomer in the cathode catalyst and improve the utilization efficiency of platinum. The prepared membrane electrode can achieve a higher voltage and realize efficient operation.

[0005] In a first aspect of the present application, a method for preparing a cathode catalyst slurry for a proton exchange membrane fuel cell is provided, wherein the cathode catalyst slurry comprises the following components in parts by weight: 10 to 15 parts of a perfluorosulfonic acid resin composition, 16 to 17 parts of a Pt / C catalyst, 0.4 to 1.6 parts of a cathode additive, and 4,000 to 5,000 parts of a first solvent;

[0006] Wherein, the cathode additive is selected from one or more of amino multi-walled carbon nanotubes, carboxyl multi-walled carbon nanotubes, conductive polyaniline, oxidized conductive carbon black, fluorinated conductive carbon black and conductive carbon black; the first solvent includes water and an alcohol with a carbon number of ≤4; the perfluorosulfonic acid resin composition includes a second solvent and 25wt% to 27wt% of a perfluorosulfonic acid resin by mass, and the second solvent includes water;

[0007] The preparation method comprises the following steps:

[0008] Mixing the perfluorosulfonic acid resin solution with the cathode additive and performing ultrasonic treatment to obtain a mixture;

[0009] The Pt / C catalyst and the first solvent are sequentially added to the mixture, and ultrasonic treatment is performed to obtain the cathode catalyst slurry.

[0010] In a second aspect of the present application, a proton exchange membrane fuel cell cathode catalyst layer is provided. The cathode catalyst layer comprises, by weight, 2.5 to 4.05 parts of perfluorosulfonic acid resin, 0.4 to 1.6 parts of cathode additive and 16 to 17 parts of Pt / C catalyst.

[0011] In some embodiments, the cathode catalyst layer satisfies one or more of the following characteristics:

[0012] The EW value of the perfluorosulfonic acid resin is 790 g eq. -1 ~980g eq -1 ;

[0013] The ion exchange capacity of the perfluorosulfonic acid resin is 0.98 meq g -1 ~1.30meq g -1 ;

[0014] The mass percentage of Pt in the Pt / C catalyst is 20wt% to 50wt%;

[0015] The mass ratio of the cathode additive to the Pt / C catalyst carbon matrix is ​​1:(5-20).

[0016] The third aspect of the present application provides a membrane electrode for a proton exchange membrane fuel cell, the membrane electrode comprising a cathode catalyst layer, a proton exchange membrane and an anode catalyst layer; wherein the cathode catalyst layer is as described in the second aspect.

[0017] In some embodiments, the membrane electrode satisfies one or more of the following characteristics:

[0018] The proton exchange membrane is a perfluorosulfonic acid resin membrane;

[0019] The thickness of the proton exchange membrane is 10 μm to 20 μm;

[0020] The thickness of the cathode catalyst layer is 5 μm to 8 μm;

[0021] The thickness of the proton exchange membrane is 5 μm to 8 μm.

[0022] In a fourth aspect of the present application, a method for preparing a membrane electrode of a proton exchange membrane fuel cell is provided, comprising the following steps:

[0023] The cathode catalyst slurry and the anode catalyst slurry are respectively deposited on two opposite surfaces of the proton exchange membrane by ultrasonic spraying, and a cathode catalyst layer and an anode catalyst layer are respectively formed on the two side surfaces of the proton exchange membrane to obtain the membrane electrode; wherein the cathode catalyst slurry is as described in the first aspect or the cathode catalyst layer is as described in the second aspect.

[0024] In some embodiments, in the preparation method, the anode catalyst slurry comprises the following components in parts by weight: 10 to 15 parts of a perfluorosulfonic acid resin solution, 16 to 17 parts of a Pt / C catalyst, and 4,000 to 5,000 parts of a first solvent;

[0025] The perfluorosulfonic acid resin, the Pt / C catalyst, the first solvent and the corresponding components in the cathode catalyst slurry are the same.

[0026] In some embodiments, in the preparation method, the cathode catalyst slurry and the anode catalyst slurry are respectively deposited on the opposite sides of the proton exchange membrane by ultrasonic spraying, which comprises the following steps: placing the proton exchange membrane on a 70°C to 90°C electric hot plate, fixing it with negative pressure, spraying the cathode catalyst slurry and the anode catalyst slurry on both sides of the proton exchange membrane, respectively, and controlling the discharge flow rate during spraying to 0.1 mL s -1 ~0.5mL s -1 .

[0027] In the fifth aspect of the present application, a proton exchange membrane fuel cell is provided, comprising a membrane electrode of a proton exchange membrane fuel cell, wherein the membrane electrode of the proton exchange membrane fuel cell is the membrane electrode of the proton exchange membrane fuel cell described in the third aspect, or is prepared according to the preparation method of the membrane electrode of the proton exchange hydrogen membrane fuel cell described in the fourth aspect.

[0028] The sixth aspect of the present application provides a method for preparing the cathode catalyst slurry of a proton exchange membrane fuel cell described in the first aspect, the cathode catalyst layer of a proton exchange membrane fuel cell described in the second aspect, the membrane electrode of a proton exchange membrane fuel cell described in the third aspect, or the membrane electrode of a proton exchange hydrogen membrane fuel cell prepared by the preparation method described in the fourth aspect, and their use in the manufacture of a proton exchange membrane fuel cell.

[0029] The preparation method of the cathode catalyst slurry of the proton exchange membrane fuel cell provided in the present application adopts amino multi-walled carbon nanotubes, carboxyl multi-walled carbon nanotubes, conductive polyaniline, oxidized conductive carbon black, fluorinated conductive carbon black and conductive carbon black as cathode additives, and pre-mixes and disperses them with a perfluorosulfonic acid resin solution to achieve pre-regulation of the morphology and distribution of the perfluorosulfonic acid resin; the cathode additive is partially combined with the sulfonic acid group in the perfluorosulfonic acid resin to reduce the excessive coverage of the sulfonic acid group in the perfluorosulfonic acid resin on the Pt / C catalyst, which is beneficial to balance the intermolecular force between the ionomer in the perfluorosulfonic acid resin and the Pt / C catalyst; on the one hand, it is beneficial to obtain a better proton transport network, and on the other hand, it reduces the coverage of the ionomer on the platinum site in the catalyst layer structure, which can improve the unreasonable assembly and distribution state of the ionomer in the catalyst layer of the membrane electrode, thereby reducing the poisoning of the sulfonic acid group of the ionomer to the platinum and improving the accessibility of oxygen to the platinum.

[0030] The intermolecular forces between the ionomers in the perfluorosulfonic acid resin and the Pt / C catalyst in the cathode catalyst layer of the proton exchange membrane fuel cell provided in the present application are relatively suitable, a better proton transport network can be obtained, and the coverage of the platinum sites in the Pt / C catalyst by the ionomers of the perfluorosulfonic acid resin is beneficial to improving the utilization rate of platinum by the cathode catalyst.

[0031] The distribution of ionomers in the cathode catalyst layer in the membrane electrode of the proton exchange membrane fuel cell provided in the present application is uniform, the coverage of platinum by the ionomer sulfonic acid groups is reduced, the poisoning effect on platinum is low, and the cathode oxygen transmission resistance is low, which helps to improve the utilization rate of the platinum-based catalyst, achieve a higher voltage and realize efficient operation of the membrane electrode.

[0032] The preparation method of the membrane electrode of the proton exchange membrane fuel cell provided in the present application is simple, fast and easy to implement, and can prepare the membrane electrode of the proton exchange membrane fuel cell with lower perfluorosulfonic acid resin content and higher platinum utilization rate.

[0033] The proton exchange membrane fuel cell provided in the present application has a membrane electrode in which the cathode has low oxygen transmission resistance and high utilization rate of the platinum catalyst. The proton exchange membrane fuel cell can operate efficiently at a higher voltage.

[0034] The cathode catalyst slurry preparation method, catalytic layer, membrane electrode and preparation method thereof provided in the present application combine conductivity, stability, safety as well as cost and environmental protection requirements, and the preparation method is simple, fast, easy to implement, and conducive to actual production application. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0036] Figure 1 The proton exchange membrane fuel cell membrane electrode prepared in Examples 1 to 4 and Comparative Example 1 is 0.0 to 2.0 Acm -1 The voltage measured within the range.

[0037] Figure 2 The proton exchange membrane fuel cell membrane electrode prepared in Example 1, Example 5 and Comparative Example 1 is 0.0-2.0Acm -1 The voltage measured within the range.

[0038] Figure 3 This is a schematic diagram of preparing cathode catalyst slurry according to an embodiment of the present invention. DETAILED DESCRIPTION

[0039] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below, and preferred embodiments of the present invention are provided. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0040] The implementation of the present invention is described in detail below in conjunction with the accompanying drawings. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0042] the term

[0043] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0044] In the present invention, "plurality", "multiple" and the like, unless otherwise specified, refer to a number greater than or equal to 2. For example, "one or more" means one or greater than or equal to two.

[0045] In the present invention, the terms “further”, “particularly”, etc. are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present invention.

[0046] In the present invention, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0047] In the present invention, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum value and the maximum value) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers in the numerical interval, including the two endpoint integers of the numerical range, and each integer between the two endpoints, is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed herein should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows broadly including numerical interval types such as percentage intervals, ratio intervals, and ratio intervals.

[0048] In the present invention, the term "room temperature" generally refers to 4°C to 35°C, preferably 20°C ± 5°C. In some embodiments of the present invention, room temperature refers to 20°C to 30°C.

[0049] In the present invention, unless otherwise specified, the temperature parameter is allowed to be either a constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the precision range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0050] In the present invention, when it comes to the unit of the data range, if there is a unit only after the right endpoint, it means that the units of the left endpoint and the right endpoint are the same. For example, 2-5h means that the units of the left endpoint "2" and the right endpoint "5" are both h (hours).

[0051] Proton Exchange Membrane Fuel Cell (PEMFC) technology is considered to be a new energy technology that is cleaner than lithium secondary battery technology. Proton Exchange Membrane Fuel Cell using hydrogen as raw material is also one of the key technologies for hydrogen energy application. In mainstream technology, hydrogen fuel cells use membrane electrodes with high platinum-carbon catalyst content, which results in high costs for hydrogen fuel cells, limiting their large-scale application.

[0052] The Pt / C catalyst in the catalyst layer of PEMFC is the core component. In traditional technology, the Pt / C catalyst is often diluted with a perfluorosulfonic acid resin solution to prepare a slurry. Commercial perfluorosulfonic acid (PFSA) ionomers act as a binder for catalyst particles and provide a pathway for proton transport. However, during the operation of the fuel cell, the ionomers tend to tightly cover the surface of the catalyst particle aggregates, affecting the transmission of oxygen; at the same time, the sulfonic acid groups of the perfluorosulfonic acid resin can be strongly adsorbed on the Pt surface, causing poisoning of the active sites and reducing the utilization of platinum.

[0053] There are literature reports that the introduction of hydrophilic carbon nanotubes as an additive for cathode slurry can produce membrane electrodes with good moisture retention and proton conduction capabilities. However, this method is not conducive to cathode drainage after the battery has been running for a period of time; some literature records the use of dispersions containing carbon nanotubes as membrane electrode slurry additives to construct a three-dimensional conductive network of the catalyst layer, but it often requires complex processing processes, such as a long ball milling step that increases production costs; and some technical data record that the catalyst slurry for membrane electrodes uses compounds or polymers containing at least two nitrogen-containing functional groups (such as diamine) as additives. This additive can adjust the morphology of perfluorosulfonic acid resins so that the catalyst layer is not prone to cracking. The additive is highly toxic and the removal conditions are harsh, which is not conducive to large-scale commercial use.

[0054] The inventors of the present application have developed a cathode catalyst layer, a membrane electrode, a preparation method and an application which have good comprehensive performances of conductivity, stability and safety and meet the requirements of cost and environmental protection.

[0055] In a first aspect of the present application, a method for preparing a cathode catalyst slurry for a proton exchange membrane fuel cell is provided, wherein the cathode catalyst slurry comprises the following components in parts by weight: 10 to 15 parts of a perfluorosulfonic acid resin composition, 16 to 17 parts of a Pt / C catalyst, 0.4 to 1.6 parts of a cathode additive, and 4,000 to 5,000 parts of a first solvent;

[0056] Wherein, the cathode additive is selected from one or more of amino multi-walled carbon nanotubes, carboxylated multi-walled carbon nanotubes, conductive polyaniline, oxidized conductive carbon black, fluorinated conductive carbon black and conductive carbon black; the first solvent includes water and an alcohol with a carbon atom number ≤ 4; the perfluorosulfonic acid resin composition includes a second solvent and a perfluorosulfonic acid resin with a mass percentage of 25wt% to 27wt%, and the second solvent includes water.

[0057] In some embodiments, the preparation method of the cathode catalyst slurry of the proton exchange membrane fuel cell, the cathode catalyst slurry comprises the following components in parts by weight: 10 to 15 parts of a perfluorosulfonic acid resin composition, 16 to 17 parts of a Pt / C catalyst, 0.4 to 1.6 parts of a cathode additive, and 4000 to 5000 parts of a first solvent;

[0058] The perfluorosulfonic acid resin composition comprises a second solvent and 25wt% to 27wt% of a perfluorosulfonic acid resin; the cathode additive is selected from one or more of amino multi-walled carbon nanotubes, carboxylated multi-walled carbon nanotubes, conductive polyaniline, oxidized conductive carbon black, fluorinated conductive carbon black and conductive carbon black; the first solvent is selected from isopropanol;

[0059] The preparation method comprises the following steps:

[0060] P100: mixing the perfluorosulfonic acid resin solution and the cathode additive, and performing ultrasonic treatment to obtain a mixture;

[0061] P200: adding the Pt / C catalyst and the first solvent to the mixture in sequence, and performing ultrasonic treatment to obtain the cathode catalyst slurry.

[0062] The preparation method of the cathode catalyst slurry of the proton exchange membrane fuel cell provided in the present application adopts amino multi-walled carbon nanotubes, carboxyl multi-walled carbon nanotubes, conductive polyaniline, oxidized conductive carbon black, fluorinated conductive carbon black and conductive carbon black as cathode additives, and pre-mixes and disperses them with a perfluorosulfonic acid resin solution. The cathode additives are partially combined with the sulfonic acid group in the perfluorosulfonic acid resin to reduce the excessive coverage of the sulfonic acid group in the perfluorosulfonic acid resin on the Pt / C catalyst, which is beneficial to balance the intermolecular force between the ionomer in the perfluorosulfonic acid resin and the Pt / C catalyst; on the one hand, it is beneficial to obtain a better proton transport network, and on the other hand, it reduces the coverage of the ionomer on the platinum site in the catalyst layer structure, which can improve the unreasonable assembly and distribution state of the ionomer in the catalyst layer of the membrane electrode, thereby achieving the reduction of the poisoning of the sulfonic acid group of the ionomer to the platinum and improving the accessibility of oxygen to the platinum.

[0063] The proton exchange membrane fuel cell in this application, unless otherwise specified, refers to a fuel cell using hydrogen as a raw material.

[0064] In some embodiments, in the method for preparing the cathode catalyst slurry, the cathode catalyst slurry includes 10 to 15 parts of a perfluorosulfonic acid resin solution, and can also be selected from any one of the following weight parts or any two weight parts: 10 parts, 10.5 parts, 11 parts, 11.5 parts, 12 parts, 12.5 parts, 13 parts, 13.5 parts, 14 parts, 14.5 parts, 15 parts, etc. A more suitable weight part of perfluorosulfonic acid resin in the cathode catalyst slurry is more conducive to the reasonable pre-combination of the cathode additive with the perfluorosulfonic acid resin in the perfluorosulfonic acid resin solution, reducing the coverage of the ionomer and the platinum site in the Pt / C catalyst, and is also conducive to the formation of a three-phase reaction interface.

[0065] In some embodiments, in the preparation method of the cathode catalyst slurry, the cathode catalyst slurry includes 16 to 17 parts of Pt / C catalyst in parts by weight, and can further be 16 to 16.5 parts, and can also be selected from the following any one or two parts by weight: 16 parts, 16.1 parts, 16.2 parts, 16.3 parts, 16.4 parts, 16.5 parts, 16.6 parts, 16.7 parts, 16.8 parts, 16.9 parts, 17 parts, etc.

[0066] In some embodiments, in the preparation method of the cathode catalyst slurry, the cathode catalyst slurry includes 0.4 to 1.6 parts of cathode additives in terms of weight, and can also be selected from any one of the following weight parts or an interval consisting of any two weight parts: 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, etc. A more suitable cathode additive in the cathode catalyst slurry is more conducive to improving the assembly morphology of the perfluorosulfonic acid resin; if the cathode additive in the cathode catalyst slurry is too high, the catalytic layer will be too thick, affecting the mass transfer in the catalytic layer; if the cathode additive in the cathode catalyst slurry is too low, it will not be able to fully play a role in regulating the assembly morphology of the perfluorosulfonic acid resin.

[0067] In some embodiments, in the method for preparing the cathode catalyst slurry, the cathode catalyst slurry includes 4000 to 5000 parts of the first solvent by weight, and can also be selected from any one of the following weight parts or any two weight parts: 4000, 4200, 4400, 4600, 4800, 5000, etc. The first solvent in the cathode catalyst slurry has an appropriate weight part, that is, an appropriate ratio with other components, which can improve the compatibility of each component with the solvent system, is more conducive to the dispersion of each component, and is also conducive to maintaining the stability of the slurry.

[0068] In some embodiments, in the method for preparing the cathode catalyst slurry, the water in the first solvent is deionized water. Using water as a solvent component can prevent the Pt / C catalyst from directly contacting the alcohol solvent during the preparation of the cathode catalyst slurry and causing combustion or failure due to low activity.

[0069] In some embodiments, in the method for preparing the cathode catalyst slurry, the mass ratio of deionized water and isopropanol in the first solvent is 1:(1-1.5), and can also be selected from any one of the following mass ratios or an interval consisting of any two mass ratios: 1:1, 1:1.1, 1:1.2, 1:1.274, 1:1.3, 1:1.4, 1:1.5, etc.

[0070] The present application also provides a cathode catalyst slurry, which comprises the following components in parts by weight: 10 to 15 parts of a perfluorosulfonic acid resin composition, 16 to 17 parts of a Pt / C catalyst, 0.4 to 1.6 parts of a cathode additive, and 4,000 to 5,000 parts of a first solvent;

[0071] Wherein, the cathode additive is selected from one or more of amino multi-walled carbon nanotubes, carboxylated multi-walled carbon nanotubes, conductive polyaniline, oxidized conductive carbon black, fluorinated conductive carbon black and conductive carbon black; the first solvent includes water and an alcohol with a carbon atom number ≤ 4; the perfluorosulfonic acid resin composition includes a second solvent and a perfluorosulfonic acid resin with a mass percentage of 25wt% to 27wt%, and the second solvent includes water.

[0072] There is an electrostatic interaction between the cathode additive and the perfluorosulfonic acid resin, which are connected by intermolecular forces or hydrogen bonds; at this time, the sulfonic acid groups in the perfluorosulfonic acid resin are well oriented and the coverage of the Pt / C catalyst is appropriate, which can provide a better proton transfer network and electron transfer channel while avoiding excessive coverage of the Pt / C catalyst.

[0073] In a second aspect of the present application, a cathode catalyst layer of a proton exchange membrane fuel cell is provided. The cathode catalyst layer comprises, by weight, 2.5 to 4.05 parts of the perfluorosulfonic acid resin composition, 0.4 to 1.6 parts of the cathode additive and 16 to 17 parts of the Pt / C catalyst.

[0074] The intermolecular forces between the ionomers in the perfluorosulfonic acid resin and the Pt / C catalyst in the cathode catalyst layer of the proton exchange membrane fuel cell provided in the present application are relatively suitable, a better proton transport network can be obtained, and the coverage of the platinum sites in the Pt / C catalyst by the ionomers of the perfluorosulfonic acid resin is beneficial to improving the utilization rate of platinum by the cathode catalyst.

[0075] In some embodiments, the cathode catalyst layer of the proton exchange membrane fuel cell is obtained by drying the cathode catalyst slurry described in the first aspect.

[0076] In some embodiments, the cathode catalyst layer includes 2.5 to 4.05 parts of perfluorosulfonic acid resin by weight, and can also be selected from any one of the following weight parts or any two weight parts: 2.5, 2.7, 2.75, 2.97, 3, 3.24, 3.25, 3.3, 3.5, 3.51, 3.564, 3.75, 3.78, 4.05, etc. A more suitable weight of perfluorosulfonic acid resin in the cathode catalyst layer is more conducive to the formation of an effective three-phase reaction interface; if the weight of perfluorosulfonic acid resin in the cathode catalyst layer is too high, it will cause poisoning of the catalyst platinum site and hinder oxygen transmission; if the weight of perfluorosulfonic acid resin in the cathode catalyst layer is too low, the proton transmission capacity of the catalyst layer will be deteriorated.

[0077] In some embodiments, the cathode catalyst layer includes 0.4 to 1.6 parts of cathode additives by weight, and can also be selected from any one of the following weight parts or an interval consisting of any two weight parts: 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, etc. A more suitable cathode additive in the cathode catalyst layer is more conducive to improving the assembly morphology of the perfluorosulfonic acid resin; if the cathode additive in the cathode catalyst layer has too high a weight fraction, the catalyst layer will be too thick, affecting the mass transfer in the catalyst layer; if the cathode additive in the cathode catalyst layer has too low a weight fraction, it will not be able to fully play a role in regulating the assembly morphology of the perfluorosulfonic acid resin.

[0078] Commercial perfluorosulfonic acid (PFSA) ionomers act as binders for catalyst particles and can provide a pathway for proton transport. However, during fuel cell operation, ionomers tend to tightly cover the surface of catalyst particle aggregates, affecting the transmission of oxygen; at the same time, the sulfonic acid groups of perfluorosulfonic acid resins can be strongly adsorbed on the Pt surface, causing poisoning of active sites and reducing the utilization of platinum. At the same time, the formation of an effective three-phase interface in the catalytic layer depends on the close contact between the catalyst and the ionomer. Therefore, it is necessary to balance proton transport while minimizing the coverage of the ionomer on platinum.

[0079] In some embodiments, the cathode catalyst layer includes 16 to 17 parts of Pt / C catalyst by weight, and can further be 16 to 16.5 parts, and can also be selected from any one or two of the following weight parts: 16 parts, 16.1 parts, 16.2 parts, 16.3 parts, 16.4 parts, 16.5 parts, 16.6 parts, 16.7 parts, 16.8 parts, 16.9 parts, 17 parts, etc.

[0080] In some embodiments, in the cathode catalyst layer, the EW value of the perfluorosulfonic acid resin is 790 g eq -1 ~980g eq -1 , can also be selected from any one or two of the following weight parts: 790g eq -1 , 800g eq -1 , 810g eq -1 , 820g eq -1 , 830g eq -1 , 840g eq -1 , 850g eq -1 、860g eq -1 , 870g eq -1 、880g eq -1 , 890g eq -1 , 900g eq -1 、909g eq -1 、910g eq -1 、920g eq -1 , 930g eq -1 , 940g eq -1 , 950g eq -1 , 960g eq -1 , 970g eq -1 、980g eq -1 wait.

[0081] In some embodiments, in the cathode catalyst layer, the ion exchange capacity of the perfluorosulfonic acid resin is 0.98 meq g -1 ~1.30meq g -1 , and can also be selected from any one of the following ion exchange capacities or any two of the following ion exchange capacities: 0.98 meq g -1 , 0.99meq g -1 , 1 meq g -1 , 1.01meq g -1 , 1.02meq g -1 , 1.03meq g -1 , 1.04meq g -1 , 1.05meq g -1 , 1.06meq g -1 , 1.07meq g -1 , 1.08meq g -1 , 1.09meq g -1 , 1.1meqg -1 , 1.11meq g -1 , 1.12meq g -1 , 1.13meq g -1 , 1.14meq g -1 , 1.15meq g -1 , 1.16meq g -1 , 1.17meq g -1 , 1.18meq g -1 , 1.19meq g -1 , 1.2meq g -1 , 1.21meq g -1 , 1.22meq g -1 , 1.23meq g -1 , 1.24meq g -1 , 1.25meq g -1 , 1.26meq g -1 , 1.27meq g -1 , 1.28meq g -1 , 1.29meq g -1 、1.3meqg -1 wait.

[0082] In some embodiments, in the cathode catalytic layer, the mass percentage of Pt in the Pt / C catalyst is 20wt% to 50wt%, and can also be selected from any one of the following mass percentages or an interval consisting of any two mass percentages: 20wt%, 30wt%, 31wt%, 32wt%, 33wt%, 34wt%, 35wt%, 36wt%, 37wt%, 38wt%, 39wt%, 40wt%, 41wt%, 42wt%, 43wt%, 44wt%, 45wt%, 46wt%, 47wt%, 48wt%, 49wt%, 50wt%, etc.

[0083] In some embodiments, in the cathode catalyst layer, the mass ratio of the cathode additive to the Pt / C catalyst carbon matrix is ​​1:(5-20), and can also be selected from any one of the following mass ratios or an interval consisting of any two mass ratios: 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.15, 1:8.5, 1:9, 1:9.5, 1:10, 1:10.5, 1:11, 1:11.5, 1:12, 1:12.5, 1:13, 1:13.5, 1:14, 1:14.5, 1:15, 1:15.5, 1:16, 1:16.5, 1:17, 1:17.5, 1:18, 1:18.5, 1:19, 1:19.5, 1:20, etc.

[0084] The third aspect of the present application provides a membrane electrode for a proton exchange membrane fuel cell, the membrane electrode comprising a cathode catalyst layer, a proton exchange membrane and an anode catalyst layer; wherein the cathode catalyst layer is as described in the second aspect.

[0085] The distribution of ionomers in the cathode catalyst layer in the membrane electrode of the proton exchange membrane fuel cell provided in the present application is uniform, the coverage of platinum by the ionomer sulfonic acid groups is reduced, the poisoning effect on platinum is low, and the cathode oxygen transmission resistance is low, which helps to improve the utilization rate of the platinum-based catalyst, achieve a higher voltage and realize efficient operation of the membrane electrode.

[0086] In this application, unless otherwise specified, membrane electrode assembly (MEA) refers to a component with an anode catalyst layer, a cathode catalyst layer and a proton exchange membrane (PEM) as the core, wherein the anode catalyst layer and the cathode catalyst layer can be collectively referred to as a catalyst layer (catalyst layer, CL). Generally speaking, the membrane electrode also includes a diffusion layer (gas diffusion layer, GDL). According to the production process of the membrane electrode, the membrane electrode in this application is a catalyst coated membrane electrode (catalyst coated-membrane, CCM) type membrane electrode.

[0087] In some embodiments, in the membrane electrode, the cathode and / or anode platinum loading is 0.1 mg Pt cm -2 .

[0088] In some embodiments, in the membrane electrode, the electrode area is 7×7 cm 2 .

[0089] In some embodiments, in the membrane electrode, the proton exchange membrane is a perfluorosulfonic acid resin membrane.

[0090] In some embodiments, in the membrane electrode, the thickness of the proton exchange membrane is 10 μm to 20 μm, and can also be selected from any one or two of the following thicknesses: 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, etc.

[0091] In some embodiments, in the membrane electrode, the thickness of the cathode catalyst layer is 5 μm to 8 μm, and can also be selected from the following intervals consisting of any one or two thicknesses: 5 μm, 6 μm, 7 μm, 8 μm, etc.

[0092] In some embodiments, in the membrane electrode, the thickness of the anode exchange membrane is 5 μm to 8 μm, and can also be selected from the following thickness range or any two thickness ranges: 5 μm, 6 μm, 7 μm, 8 μm, etc.

[0093] In some embodiments, the membrane electrode further comprises a gas diffusion layer, which can be a single piece or multiple pieces. The thickness of the single layer of the gas diffusion layer is 220 μm; and a H23C2 type gas diffusion layer can be selected.

[0094] In a fourth aspect of the present application, a method for preparing a membrane electrode of a proton exchange membrane fuel cell is provided, comprising the following steps:

[0095] The cathode catalyst slurry and the anode catalyst slurry are respectively deposited on two opposite surfaces of the proton exchange membrane by ultrasonic spraying, and a cathode catalyst layer and an anode catalyst layer are respectively formed on the two side surfaces of the proton exchange membrane to obtain the membrane electrode; wherein the cathode catalyst slurry is as described in the first aspect or the cathode catalyst layer is as described in the second aspect.

[0096] The preparation method of the membrane electrode of the proton exchange membrane fuel cell provided in the present application is simple, fast and easy to implement, and can prepare the membrane electrode of the proton exchange membrane fuel cell with lower perfluorosulfonic acid resin content and higher platinum utilization rate.

[0097] In some embodiments, in the preparation method, the anode catalyst slurry comprises the following components in parts by weight: 10 to 15 parts of perfluorosulfonic acid resin solution, 16 to 17 parts of Pt / C catalyst and 4000 to 5000 parts of the first solvent.

[0098] In some embodiments, in the preparation method, the perfluorosulfonic acid resin, the Pt / C catalyst, the first solvent and the corresponding components in the cathode catalyst slurry are the same.

[0099] In some embodiments, in the preparation method, the anode catalyst slurry includes 10 to 15 parts of perfluorosulfonic acid resin in parts by weight, and can also be selected from any one of the following parts by weight or an interval consisting of any two parts by weight: 10 parts, 10.5 parts, 11 parts, 11.5 parts, 12 parts, 12.5 parts, 13 parts, 13.5 parts, 14 parts, 14.5 parts, 15 parts, etc.

[0100] In some embodiments, in the preparation method, the anode catalyst slurry includes 16 to 17 parts of Pt / C catalyst in parts by weight, and can further be 16 to 16.5 parts, and can also be selected from any one or two parts by weight of the following intervals: 16 parts, 16.1 parts, 16.2 parts, 16.3 parts, 16.4 parts, 16.5 parts, 16.6 parts, 16.7 parts, 16.8 parts, 16.9 parts, 17 parts, etc.

[0101] In some embodiments, in the preparation method, the anode catalyst slurry includes 4000 to 5000 parts of the first solvent, and can further be 4000 to 4500 parts, and can also be selected from 4000, 4100, 4200, 4300, 4373, 4400, 4500, 4600, 4700, 4800, 4900, 5000 parts, etc., by weight.

[0102] In some embodiments, in the membrane electrode preparation method, the cathode catalyst slurry and the anode catalyst slurry are deposited on the opposite sides of the proton exchange membrane by ultrasonic spraying, which includes the following steps: placing the proton exchange membrane on a hot plate, fixing it with negative pressure, and spraying the cathode catalyst slurry and the anode catalyst slurry on both sides of the proton exchange membrane.

[0103] In some embodiments, in the membrane electrode preparation method, the cathode catalyst slurry and the anode catalyst slurry are deposited on the opposite sides of the proton exchange membrane by ultrasonic spraying, which comprises the following steps: placing the proton exchange membrane on a 70°C to 90°C electric hot plate, fixing it with negative pressure, spraying the cathode catalyst slurry and the anode catalyst slurry on both sides of the proton exchange membrane, respectively, and controlling the discharge flow rate during spraying to 0.1 mL s -1 ~0.5mL s -1 .

[0104] In a fifth aspect of the present application, a proton exchange membrane fuel cell is provided, comprising a membrane electrode of a proton exchange membrane fuel cell, wherein the membrane electrode of the proton exchange membrane fuel cell is the membrane electrode of the proton exchange membrane fuel cell described in the third aspect, or is prepared by the preparation method of the membrane electrode of the proton exchange hydrogen membrane fuel cell described in the fourth aspect.

[0105] The proton exchange membrane fuel cell provided in the present application has a membrane electrode in which the cathode has low oxygen transmission resistance and high utilization rate of the platinum catalyst. The proton exchange membrane fuel cell can operate efficiently at a higher voltage.

[0106] The sixth aspect of the present application provides an application of the proton exchange membrane fuel cell cathode catalyst slurry described in the first aspect, the proton exchange membrane fuel cell cathode catalyst composition described in the second aspect, the membrane electrode of the proton exchange membrane fuel cell described in the third aspect, or the membrane electrode of the proton exchange hydrogen membrane fuel cell prepared by the preparation method described in the fourth aspect in the manufacture of a proton exchange membrane fuel cell.

[0107] The cathode catalyst slurry preparation method, catalyst composition, membrane electrode and preparation method thereof provided in the present application combine conductivity, stability, safety as well as cost and environmental protection requirements, and the preparation method is simple, fast, easy to implement, and conducive to actual production application.

[0108] In order to make it easier to understand and implement the present invention, the following more specific and detailed embodiments and comparative examples which are easier to implement are provided as references.

[0109] The following will further illustrate the concept, specific examples and technical effects of the present invention in conjunction with the accompanying drawings to fully understand the present invention. The purpose of providing these descriptions is only to help explain the present invention and should not be used to limit the scope of the claims of the present invention.

[0110] Unless otherwise specified, the raw materials used in the following experiments can be purchased from the market.

[0111] Example 1

[0112] (1) Take 13.2 mg of perfluorosulfonic acid resin solution (the EW value of dry perfluorosulfonic acid resin is 790 g eq. -1 , ion exchange capacity is 1.15meq g -1 ; The solid content of perfluorosulfonic acid resin in the perfluorosulfonic acid resin solution is 25-27wt%), add 2.45mL of deionized water, shake well, and obtain a diluted perfluorosulfonic acid resin solution. Then weigh 1mg of amino-modified multi-walled carbon nanotubes (key specifications: purity>95%, outer diameter 8-15nm, length ~50μm), place it in a round-bottom glass bottle, add the diluted perfluorosulfonic acid resin solution, and ultrasonically treat for 20min to make the mixture evenly dispersed. Then add 16.3mg of commercial 50wt% Pt / C catalyst, shake well, and after the catalyst is completely wetted, add 2.45mL of isopropanol to the mixture. Ultrasonicate the final mixture for 60min to obtain a cathode catalyst slurry.

[0113] (2) 13.2 mg of perfluorosulfonic acid resin solution was placed in a round bottom glass bottle, 2.45 mL of deionized water was added, and the mixture was shaken. Then 16.3 mg of commercial 50 wt% Pt / C catalyst was added, and the mixture was shaken. After the catalyst was completely wetted, 2.45 mL of isopropanol was added to the mixture. The final mixture was ultrasonically treated for 60 min to obtain an anode catalyst slurry.

[0114] (3) Place the commercial proton exchange membrane on an 80°C hot plate and fix it using the negative pressure of an air compressor. Use an ultrasonic automatic spraying device to control the discharge flow rate to 0.2 mL s -1 , the cathode and anode catalyst slurries are sprayed on both sides of the proton exchange membrane respectively to obtain a membrane electrode CCM.

[0115] Membrane electrode composition specifications:

[0116] The platinum loading of cathode and anode is 0.1 mg Pt cm -2 , using H23C2 type gas diffusion layer, electrode area is 7×7cm 2 .

[0117] Embodiments 2 to 4

[0118] The preparation methods of the proton exchange membrane fuel cell membrane electrodes in Examples 2 to 4 are basically the same as those in Example 1, except that in step (1), the cathode additive in Example 1 is replaced by carboxylated multi-walled carbon nanotubes (key specifications: purity>98%, tube diameter 5-15nm, tube length 10-30μm, specific surface area 220-300m 2 g -1 , ash content <1.5%), conductive carbon black (key specifications: particle size ~30nm, specific surface area ~254m 2 g -1 ) and conductive polyaniline powder.

[0119] Example 5

[0120] The method for preparing the proton exchange membrane fuel cell membrane electrode in Example 5 is substantially the same as that in Example 1, except that step (1) is as follows:

[0121] (1) 13.2 mg of perfluorosulfonic acid resin solution was weighed and 2.45 mL of deionized water was added. Then 16.3 mg of commercial 50 wt% Pt / C catalyst and 1 mg of amino-modified multi-walled carbon nanotubes (key specifications: purity > 95%, outer diameter 8-15 nm, length ~ 50 μm) were added and shaken well. Finally, 2.45 mL of isopropanol was added to the mixture. The final mixture was ultrasonically treated for 60 min to obtain a cathode catalyst slurry.

[0122] Comparative Example 1

[0123] The preparation method of the proton exchange membrane fuel cell membrane electrode in Comparative Example 1 is substantially the same as that in Example 1, except that the step of adding the cathode additive is omitted in step (1).

[0124] The performance test of the prepared proton exchange membrane fuel cell membrane electrode was carried out, and the specific test method is as follows:

[0125] After the membrane electrode (CCM) is sealed, the gas diffusion layers of the cathode and anode are assembled into a fuel cell test fixture for polarization testing. The test conditions are an intake pressure of 170 kPa / 150 kPa and a humidity of 50% RH.

[0126] Figure 1 The proton exchange membrane fuel cell membrane electrode prepared in Examples 1 to 4 and Comparative Example 1 is 0.0 to 2.0 Acm -1 It can be seen that the voltage measured by the membrane electrode in Examples 1 to 4 at the same current density is significantly higher than that of the membrane electrode in Comparative Example 1 in which the cathode additive is omitted in the cathode catalyst layer.

[0127] Figure 2 The proton exchange membrane fuel cell membrane electrode prepared in Example 1, Example 5 and Comparative Example 1 is 0.0-2.0Acm -1 The voltage measured in the range of . It can be seen that the voltage measured at the same current density when the membrane electrode in the embodiment is tested is significantly higher than that in the membrane electrodes in Comparative Example 1 and Example 5, wherein the voltage corresponding to the membrane electrode in Example 5 is between the voltages corresponding to the membrane electrodes in Example 1 and Comparative Example 1 when the current density is the same. The possible reason is that although the cathode catalyst layer of the membrane electrode in Example 5 contains a cathode additive, the perfluorosulfonic acid resin solution and the cathode additive are not pre-mixed and ultrasonically dispersed, so the morphological distribution of the resin is still disordered and the optimal effect is not achieved.

[0128] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

[0129] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0130] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims, and the description and drawings may be used to explain the contents of the claims.

Claims

1. A method for preparing a cathode catalyst slurry for a proton exchange membrane fuel cell, characterized in that: The cathode catalyst slurry comprises the following components in parts by weight: 10 to 15 parts of a perfluorosulfonic acid resin composition, 16 to 17 parts of a Pt / C catalyst, 0.4 to 1.6 parts of a cathode additive, and 4,000 to 5,000 parts of a first solvent; Wherein, the cathode additive is selected from one or more of amino multi-walled carbon nanotubes, carboxyl multi-walled carbon nanotubes, conductive polyaniline, oxidized conductive carbon black, fluorinated conductive carbon black and conductive carbon black; the first solvent includes water and an alcohol having a carbon number of ≤4; the perfluorosulfonic acid resin composition includes a second solvent and 25wt% to 27wt% of a perfluorosulfonic acid resin by mass, and the second solvent includes water; The preparation method comprises the following steps: Mixing the perfluorosulfonic acid resin solution with the cathode additive and performing ultrasonic treatment to obtain a mixture; The Pt / C catalyst and the first solvent are sequentially added to the mixture, and ultrasonic treatment is performed to obtain the cathode catalyst slurry.

2. A cathode catalyst layer of a proton exchange membrane fuel cell, characterized in that: In terms of weight, the cathode catalyst layer includes 2.5 to 4.05 parts of perfluorosulfonic acid resin, 0.4 to 1.6 parts of cathode additive and 16 to 17 parts of Pt / C catalyst.

3. The cathode catalyst layer according to claim 2, characterized in that: Satisfy one or more of the following characteristics: The EW value of the perfluorosulfonic acid resin is 790 g eq. -1 ~980g eq -1 ; The ion exchange capacity of the perfluorosulfonic acid resin is 0.98 meq g -1 ~1.30meq g -1 ; The mass percentage of Pt in the Pt / C catalyst is 20wt% to 50wt%; The mass ratio of the cathode additive to the Pt / C catalyst carbon matrix is ​​1:(5-20).

4. A membrane electrode for a proton exchange membrane fuel cell, characterized in that: The membrane electrode comprises a cathode catalyst layer, a proton exchange membrane and an anode catalyst layer; wherein the cathode catalyst layer is as described in claim 2 or 3.

5. The membrane electrode according to claim 4, characterized in that: Satisfy one or more of the following characteristics: The proton exchange membrane is a perfluorosulfonic acid resin membrane; The thickness of the proton exchange membrane is 10 μm to 20 μm; The thickness of the cathode catalyst layer is 5 μm to 8 μm; The thickness of the proton exchange membrane is 5 μm to 8 μm.

6. A method for preparing a membrane electrode for a proton exchange membrane fuel cell, characterized in that: The following steps are involved: The cathode catalyst slurry and the anode catalyst slurry are respectively deposited on the two opposite surfaces of the proton exchange membrane by ultrasonic spraying, and a cathode catalyst layer and an anode catalyst layer are respectively formed on the two side surfaces of the proton exchange membrane to obtain the membrane electrode; wherein the cathode catalyst slurry is as described in claim 1 or the cathode catalyst layer is as described in claim 2 or 3.

7. The preparation method according to claim 6, characterized in that: The anode catalyst slurry comprises the following components in parts by weight: 10 to 15 parts of a perfluorosulfonic acid resin solution, 16 to 17 parts of a Pt / C catalyst, and 4,000 to 5,000 parts of a first solvent; The perfluorosulfonic acid resin, the Pt / C catalyst, the first solvent and the corresponding components in the cathode catalyst slurry are the same.

8. The method for preparing a membrane electrode according to claim 6, characterized in that: The method of depositing the cathode catalyst slurry and the anode catalyst slurry on the two opposite sides of the proton exchange membrane by ultrasonic spraying comprises the following steps: placing the proton exchange membrane on a 70°C to 90°C electric heating plate, fixing it by negative pressure, spraying the cathode catalyst slurry and the anode catalyst slurry on both sides of the proton exchange membrane, respectively, and controlling the discharge flow rate during spraying to be 0.1 mL s -1 ~0.5mL s -1 .

9. A proton exchange membrane fuel cell, characterized in that: The invention comprises a membrane electrode of a proton exchange membrane fuel cell, wherein the membrane electrode of the proton exchange membrane fuel cell is the membrane electrode of the proton exchange membrane fuel cell according to claim 4 or 5, or is prepared according to the preparation method of the membrane electrode of the proton exchange membrane fuel cell according to any one of claims 6 to 8.

10. Use of the method for preparing cathode catalyst slurry of proton exchange membrane fuel cell according to claim 1, the cathode catalyst layer of proton exchange membrane fuel cell according to claim 2 or 3, the membrane electrode of proton exchange membrane fuel cell according to claim 4 or 5, or the membrane electrode of proton exchange membrane fuel cell prepared by the preparation method according to any one of claims 6 to 8 in the manufacture of proton exchange membrane fuel cells.

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