A composite electrode structure and preparation method thereof

Abstract

The present invention provides a composite electrode structure comprising a proton exchange membrane, an anode catalyst layer composited to one side of the proton exchange membrane, and a cathode catalyst layer composited to the other side of the proton exchange membrane. The present application also provides a method for preparing the composite electrode structure. The composite electrode structure provided herein comprises a multilayer stack of a catalyst layer and a three-dimensional resin fiber layer, significantly reducing proton transport resistance within the catalyst layer and improving proton transport capacity.

Description

Technical Field

[0001] The present invention relates to the field of electrode technology, and in particular to a composite electrode structure and a preparation method thereof. Background Art

[0002] Fuel cells are highly efficient and environmentally friendly, directly converting the chemical energy of fuel into electrical energy. This conversion process does not involve heat engine work and is free from the constraints of the Carnot cycle, resulting in high energy conversion efficiencies (40% to 60%). Furthermore, fuel cells emit virtually no nitrogen or sulfur emissions during operation, making them environmentally friendly. In today's world of energy scarcity and severe environmental pollution, they are attracting widespread attention as a new type of power generation device. However, the commercialization of low-temperature fuel cells is limited by the performance, cost, and lifespan of the precious metal catalysts, proton exchange membranes, and membrane electrode structures used. Improving the utilization of precious metal catalysts, improving the performance of electrolyte membranes, and optimizing membrane electrode structures have become current research hotspots.

[0003] Electrospinning technology offers significant advantages in preparing nanofibers from various materials. It requires minimal equipment investment, offers high yields, and produces nanofiber membranes with porous mesh structures and high specific surface areas. Almost any soluble organic matter with a sufficiently high molecular weight can be made into the desired fiber structure using electrospinning. Currently, resin nanofibers or catalyst layer nanofibers have been successfully produced in various morphologies, including beaded, ribbon-like, porous, and core-shell forms. Most of the resin nanofibers mentioned so far improve the three-dimensional porous structure of the proton exchange membrane surface, increasing the contact area with the catalyst layer. This structure increases the surface roughness of the catalyst layer and increases the interfacial resistance; however, improving proton transport capacity through the interface alone remains limited. Summary of the Invention

[0004] The technical problem solved by the present invention is to provide a composite electrode structure having good proton transport capability.

[0005] In view of this, the present application provides a composite electrode structure, including a proton exchange membrane, an anode catalyst layer composited on one side of the proton exchange membrane, and a cathode catalyst layer composited on the other side of the proton exchange membrane; the anode catalyst layer is one or more of a first anode catalyst layer, a second anode catalyst layer and a first resin fiber layer stacked in sequence, and a third anode catalyst layer, a second resin fiber layer and a fourth anode catalyst layer stacked in sequence; the cathode catalyst layer is one or more of a first cathode catalyst layer, a second cathode catalyst layer and a third resin fiber layer stacked in sequence, and a third cathode catalyst layer, a fourth resin fiber layer and a fourth cathode catalyst layer stacked in sequence; the first anode catalyst layer and the first cathode catalyst layer are not selected at the same time; the first resin fiber layer, the second resin fiber layer, the third resin fiber layer and the fourth resin fiber layer are all obtained by electrospinning from a resin spinning solution.

[0006] Preferably, the Pt loading in the first anode catalyst layer, the second anode catalyst layer, the third anode catalyst layer, the fourth anode catalyst layer, the first cathode catalyst layer, the second cathode catalyst layer, the third cathode catalyst layer and the fourth cathode catalyst layer is independently 0.01 to 0.5 mg / cm 2 .

[0007] Preferably, the thickness of the first resin fiber layer, the second resin fiber layer, the third resin fiber layer and the fourth resin fiber layer are independently 0.1 to 10 μm.

[0008] Preferably, the number of repeated layers of the second anode catalyst layer and the first resin fiber layer stacked in sequence and the third anode catalyst layer, the second resin fiber layer and the fourth anode catalyst layer stacked in sequence is independently ≥1, and the number of repeated layers of the second cathode catalyst layer and the third resin fiber layer stacked in sequence and the third cathode catalyst layer, the fourth resin fiber layer and the fourth cathode catalyst layer stacked in sequence is independently ≥1.

[0009] The present application also provides a method for preparing the composite electrode structure, comprising the following steps:

[0010] A) mixing a cathode catalyst, a polymer electrolyte and a solvent to obtain a cathode catalyst slurry; preparing a first cathode catalyst slurry, a second cathode catalyst slurry, a third cathode catalyst slurry and a fourth cathode catalyst slurry respectively according to the above method;

[0011] The first resin, the first polymer carrier and the solvent are mixed to obtain a first resin spinning solution; the second resin spinning solution, the third resin spinning solution and the fourth resin spinning solution are prepared respectively according to the above method;

[0012] Mixing an anode catalyst, a polymer electrolyte and a solvent to obtain an anode catalyst slurry; preparing a first anode catalyst slurry, a second anode catalyst slurry, a third anode catalyst slurry and a fourth anode catalyst slurry respectively according to the above method;

[0013] B) coating the first cathode catalytic slurry on one side of a proton exchange membrane and drying the slurry to obtain a first cathode catalytic layer;

[0014] and / or coating the second cathode catalytic slurry on one side of the proton exchange membrane, and then performing electrostatic spinning using a third resin spinning solution after drying;

[0015] and / or coating the third cathode catalytic slurry on one side of the proton exchange membrane, drying it, then electrospinning it with a fourth resin spinning solution, drying it, then coating it with a fourth cathode catalytic slurry, and drying it;

[0016] or,

[0017] B') coating the first cathode catalytic slurry on one side of the substrate, drying to obtain a first cathode catalytic layer, and transferring the first cathode catalytic layer to the surface of the proton exchange membrane;

[0018] and / or coating the second cathode catalytic slurry on one side of the proton exchange membrane, drying the slurry, and then electrospinning the slurry using a third resin spinning solution to obtain a first composite cathode layer, and transferring the first composite cathode layer to the surface of the proton exchange membrane;

[0019] and / or coating the third cathode catalytic slurry on one side of the proton exchange membrane, drying and then electrospinning with a fourth resin spinning solution, drying and then coating the fourth cathode catalytic slurry, drying to obtain a second composite cathode layer, and transferring the second composite cathode layer to the surface of the proton exchange membrane;

[0020] C) coating the first anode catalyst slurry on the other side of the proton exchange membrane and drying to obtain a first anode catalyst layer;

[0021] and / or coating the second anode catalytic slurry on the other side of the proton exchange membrane, and then performing electrostatic spinning using the first resin spinning solution after drying;

[0022] and / or coating the third anode catalytic slurry on one side of the proton exchange membrane, drying it, then electrospinning it with a second resin spinning solution, drying it, then coating it with a fourth anode catalytic slurry, and drying it;

[0023] The first anode catalyst layer and the first cathode catalyst layer are not selected at the same time.

[0024] Preferably, the first anode catalyst, the second anode catalyst layer, the third anode catalyst layer and the fourth anode catalyst layer, the first cathode catalyst layer, the second cathode catalyst, the third cathode catalyst layer and the fourth cathode catalyst layer are independently selected from platinum-carbon catalysts, platinum-based alloy catalysts or non-precious metal catalysts.

[0025] Preferably, the polymer electrolyte in the first anode catalyst slurry to the fourth anode catalyst slurry, the polymer electrolyte in the first cathode catalyst slurry to the fourth cathode catalyst slurry, and the resin in the first resin spinning solution to the fourth resin spinning solution are independently selected from one or more of long-chain branched perfluorosulfonic acid resin, short-chain branched perfluorosulfonic acid resin, sulfonated polystyrene, sulfonated polyarylethersulfone, sulfonated polyetheretherketone, polyvinylidene fluoride, polytetrafluoroethylene and tetrafluoroethylene-co-hexafluoroethylene; the polymer carrier is selected from one or more of polyacrylic acid, polyethylene oxide, polytetrafluoroethylene, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetate, polyacrylonitrile and polymethacrylate.

[0026] Preferably, the content of the polymer carrier in the first to fourth resin spinning solutions is 0.01 to 50 wt%.

[0027] Preferably, the voltage of the electrospinning is 0.1 kV to 30 kV.

[0028] Preferably, in step B) and step C), the coating is independently selected from ultrasonic spraying, electrostatic spraying, slit coating, doctor blade coating, comma coating, inkjet printing or screen printing; and the drying is independently selected from flatbed heat treatment, oven heat treatment, infrared heat treatment or hot air gun drying.

[0029] The present application provides a composite electrode structure comprising a proton exchange membrane, an anode catalyst layer composited to one side of the proton exchange membrane, a first cathode catalyst layer composited to the other side of the proton exchange membrane, and a resin fiber composite layer composited to the surface of the first cathode catalyst layer; the resin fiber composite layer comprises a resin fiber layer and a second cathode catalyst layer stacked in sequence, the resin fiber layer composited to the surface of the first cathode catalyst layer, and the number of repetitions of the resin fiber composite layer is ≥1. The composite electrode structure provided by the present application significantly improves the proton transport capacity of the catalyst layer by interspersing the resin fiber layer within the cathode catalyst layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the composite electrode structure prepared in Example 3 of the present invention;

[0031] Figure 2 25cm prepared in Examples 1 to 3 of the present invention 2 Polarization curve of membrane electrode;

[0032] Figure 3 The AC impedance curve data of the membrane electrodes prepared in Examples 1 and 3 of the present invention under H2-N2 conditions;

[0033] Figure 4 These are polarization curves of the membrane electrodes prepared in Examples 4 to 6 of the present invention. DETAILED DESCRIPTION

[0034] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0035] In view of the technical problem that the proton transport resistance of the catalyst layer in the prior art is limited, which makes it difficult to break through the performance of the traditional membrane electrode, the present application can greatly improve the proton transport capacity of the catalyst layer by inserting multiple layers of resin fiber layers with high proton conductivity inside the catalyst layer. Specifically, the embodiment of the present invention discloses a composite electrode structure, including a proton exchange membrane, an anode catalyst layer composited on one side of the proton exchange membrane, and a cathode catalyst layer composited on the other side of the proton exchange membrane; the anode catalyst layer is a first anode catalyst layer, a second anode catalyst layer and a first resin fiber layer stacked in sequence, or a third anode catalyst layer, a second resin fiber layer and a fourth anode catalyst layer stacked in sequence, the cathode catalyst layer is a first cathode catalyst layer, a second cathode catalyst layer and a third resin fiber layer stacked in sequence, or a third cathode catalyst layer, a fourth resin fiber layer and a fourth cathode catalyst layer stacked in sequence; the first anode catalyst layer and the first cathode catalyst layer are not selected at the same time; the first resin fiber layer, the second resin fiber layer, the third resin fiber layer and the fourth resin fiber layer are all obtained by electrospinning from a resin spinning solution.

[0036] In the composite electrode structure provided in the present application, it includes a proton exchange membrane, an anode catalyst layer composited on one side of the proton exchange membrane, and a cathode catalyst layer composited on the other side of the proton exchange membrane; wherein the anode catalyst layer may be a single first anode catalyst layer, a composite first anode catalyst layer or a composite second anode catalyst layer, and the cathode catalyst layer may be a single first cathode catalyst layer, a composite first cathode catalyst layer or a composite second cathode catalyst layer; specifically, the composite first anode catalyst layer is composed of a second anode catalyst layer and a first resin fiber layer stacked in sequence, and the second anode catalyst layer is in contact with the proton exchange membrane, and the composite second anode catalyst layer is composed of a third anode catalyst layer, a second resin fiber layer and a fourth anode catalyst layer stacked in sequence, and the third anode catalyst layer is in contact with the proton exchange membrane. As for the cathode catalyst layer, it can also be a single first cathode catalyst layer, a composite first cathode catalyst layer or a composite second cathode catalyst layer. The cathode catalyst layer can be a single first cathode catalyst layer, a composite first cathode catalyst layer or a composite second cathode catalyst layer; specifically, the composite first cathode catalyst layer is composed of a second cathode catalyst layer and a third resin fiber layer stacked in sequence, and the second cathode catalyst layer is in contact with the proton exchange membrane, and the composite second cathode catalyst layer is composed of a third cathode catalyst layer, a fourth resin fiber layer and a fourth cathode catalyst layer stacked in sequence, and the third cathode catalyst layer is in contact with the proton exchange membrane.

[0037] According to the present invention, the first anode catalyst layer and the first cathode catalyst layer cannot be selected at the same time. In addition, the selection of the anode catalyst layer and the cathode catalyst layer is not limited. It can be a scheme of a composite first anode catalyst layer and a first cathode catalyst layer, a method of a composite second anode catalyst layer and a first cathode catalyst layer, a scheme of a first anode catalyst layer and a composite first cathode catalyst layer, a scheme of a composite first anode catalyst layer, a composite second anode catalyst layer and a first cathode catalyst layer, etc. The number of layers of the composite first anode catalyst layer, the composite second anode catalyst layer, the composite first cathode catalyst layer and the composite second cathode catalyst layer is ≥ 1. For example, the composite electrode structure of the present application is composed of a first anode catalyst layer, a proton exchange membrane, a composite first cathode catalyst layer, and a composite first cathode catalyst layer stacked in sequence; or composed of a composite first anode catalyst layer, a composite first anode catalyst, a proton exchange membrane, and a first cathode catalyst layer stacked in sequence; or composed of a composite second anode catalyst layer, a composite first anode catalyst layer, a proton exchange membrane, a first cathode catalyst layer, a composite second cathode catalyst layer, and a composite second cathode catalyst layer stacked in sequence, etc.

[0038] In the present application, the materials selected for the first to fourth anode catalyst layers can be the same or different, and this application has no restrictions on this; similarly, the materials selected for the first to fourth cathode catalyst layers can be the same or different, and this application has no restrictions on this; similarly, the materials for the first to fourth resin fiber layers can be the same or different, and this application has no special restrictions on this.

[0039] In the present application, the Pt loading in the anode catalyst layer, the first anode catalyst layer, the second anode catalyst layer, the third anode catalyst layer, the fourth anode catalyst layer, the first cathode catalyst layer, the second cathode catalyst layer, the third cathode catalyst layer and the fourth cathode catalyst layer is independently 0.01 to 0.5 mg / cm 2 More specifically, the Pt loading in the first anode catalyst layer, the second anode catalyst layer, the third anode catalyst layer, the fourth anode catalyst layer, the first cathode catalyst layer, the second cathode catalyst layer, the third cathode catalyst layer and the fourth cathode catalyst layer is independently 0.1 to 0.3 mg / cm 2 The thickness of the first resin fiber layer, the second resin fiber layer, the third resin fiber layer, and the fourth resin fiber layer are independently 0.1 to 10 μm. More specifically, the thickness of the first resin fiber layer, the second resin fiber layer, the third resin fiber layer, and the fourth resin fiber layer are independently 1 to 8 μm.

[0040] Furthermore, the present application also provides a method for preparing a composite electrode structure, comprising the following steps:

[0041] A) mixing a cathode catalyst, a polymer electrolyte and a solvent to obtain a cathode catalyst slurry; preparing a first cathode catalyst slurry, a second cathode catalyst slurry, a third cathode catalyst slurry and a fourth cathode catalyst slurry respectively according to the above method;

[0042] The first resin, the first polymer carrier and the solvent are mixed to obtain a first resin spinning solution; the second resin spinning solution, the third resin spinning solution and the fourth resin spinning solution are prepared respectively according to the above method;

[0043] Mixing an anode catalyst, a polymer electrolyte and a solvent to obtain an anode catalyst slurry; preparing a first anode catalyst slurry, a second anode catalyst slurry, a third anode catalyst slurry and a fourth anode catalyst slurry respectively according to the above method;

[0044] B) coating the first cathode catalytic slurry on one side of a proton exchange membrane and drying the slurry to obtain a first cathode catalytic layer;

[0045] or coating the second cathode catalytic slurry on one side of the proton exchange membrane, and then using the third resin spinning solution for electrostatic spinning after drying;

[0046] or coating the third cathode catalytic slurry on one side of the proton exchange membrane, drying it, and then electrospinning it with a fourth resin spinning solution, drying it, and then coating it with a fourth cathode catalytic slurry, and drying it;

[0047] or,

[0048] B') coating the first cathode catalytic slurry on one side of the substrate, drying to obtain a first cathode catalytic layer, and transferring the first cathode catalytic layer to the surface of the proton exchange membrane;

[0049] Alternatively, the second cathode catalytic slurry is coated on one side of the proton exchange membrane, dried, and then electrospun using a third resin spinning solution to obtain a first composite cathode layer, and the first composite cathode layer is transferred to the surface of the proton exchange membrane;

[0050] Alternatively, the third cathode catalytic slurry is coated on one side of the proton exchange membrane, and after drying, a fourth resin spinning solution is used for electrospinning, and after drying, a fourth cathode catalytic slurry is coated again, and dried to obtain a second composite cathode layer, and the second composite cathode layer is transferred to the surface of the proton exchange membrane;

[0051] C) coating the first anode catalytic slurry on the other side of the proton exchange membrane and drying to obtain a first anode catalytic layer;

[0052] Alternatively, the second anode catalytic slurry is coated on the other side of the proton exchange membrane, and after drying, the first resin spinning solution is used for electrostatic spinning;

[0053] or coating the third anode catalytic slurry on one side of the proton exchange membrane, drying it, and then electrospinning it with the second resin spinning solution, drying it, and then coating it with the fourth anode catalytic slurry, and drying it;

[0054] The first anode catalyst layer and the first cathode catalyst layer are not selected at the same time.

[0055] In the preparation process of the composite electrode structure, the present application first prepares the cathode catalyst slurry, resin spinning solution, and anode catalyst slurry respectively; that is, the first cathode catalyst, polymer electrolyte and solvent are mixed to obtain cathode catalyst slurry; the resin, polymer carrier and solvent are mixed to obtain resin spinning solution; the anode catalyst, polymer electrolyte and solvent are mixed to obtain anode catalyst slurry and according to the same method, the first cathode catalyst slurry to the fourth cathode catalyst slurry, the first anode catalyst slurry to the fourth anode catalyst slurry, and the first resin spinning solution to the fourth resin spinning solution are prepared; the preparation process is specifically as described above; the raw materials involved above can be the same or different, and the present application has no special restrictions on this.

[0056] In the above slurry, the first anode catalyst, the second anode catalyst layer, the third anode catalyst layer and the fourth anode catalyst layer, the first cathode catalyst layer, the second cathode catalyst, the third cathode catalyst layer and the fourth cathode catalyst layer are independently selected from platinum-carbon catalysts, platinum-based alloy catalysts or non-precious metal catalysts (Fe-NC or Co-NC), wherein the platinum-based alloy catalyst has a core-shell structure, a nanoframe or a nanopolyhedron or other novel structure, and the platinum-based alloy catalyst or non-precious metal catalyst can be used alone or on a carbon carrier such as carbon black, carbon nanotubes or graphene; the first anode catalyst slurry to the fourth anode catalyst slurry are selected from platinum-carbon catalysts, platinum-based alloy catalysts or non-precious metal catalysts (Fe-NC or Co-NC). The polymer electrolyte in the cathode catalyst slurry, the polymer electrolyte in the first cathode catalyst slurry to the fourth cathode catalyst slurry, and the resin in the first resin spinning solution to the fourth resin spinning solution are independently selected from one or more of long-chain branched perfluorosulfonic acid resin, short-chain branched perfluorosulfonic acid resin, sulfonated polystyrene, sulfonated polyarylethersulfone, sulfonated polyetheretherketone, polyvinylidene fluoride, polytetrafluoroethylene and tetrafluoroethylene-co-hexafluoroethylene; the polymer carrier is selected from one or more of polyacrylic acid, polyethylene oxide, polytetrafluoroethylene, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetate, polyacrylonitrile and polymethacrylate. The content of the polymer carrier in the first resin spinning solution to the fourth resin spinning solution is 0.01 to 50 wt%. More specifically, the content of the polymer carrier in the first resin spinning solution to the fourth resin spinning solution is 1 to 10 wt%.

[0057] After the various slurries are prepared, the present application applies the first cathode catalytic slurry on one side of the proton exchange membrane and dries to obtain a first cathode catalytic layer; or applies the second cathode catalytic slurry on one side of the proton exchange membrane, dries, and then uses a third resin spinning solution for electrostatic spinning to obtain a composite first cathode catalytic layer; or applies the third cathode catalytic slurry on one side of the proton exchange membrane, dries, and then uses a fourth resin spinning solution for electrostatic spinning, dries, and then applies the fourth cathode catalytic slurry to obtain a composite second cathode catalytic layer. According to the present invention, a first cathode catalytic layer and a composite first cathode catalytic layer can be prepared on the surface of the proton exchange membrane, a composite first cathode catalytic layer and a composite second cathode catalytic layer can be prepared on the surface of the proton exchange membrane, and the above-mentioned composite first cathode catalytic layer and composite second cathode catalytic layer can be repeated multiple times. In the above process, the coating can be selected from ultrasonic spraying, slit coating, doctor blade coating, electrostatic spraying, comma coating, inkjet printing or screen printing; the drying can be selected from flat plate heat treatment, oven heat treatment, infrared heat treatment or hot air gun drying. The electrostatic spinning is carried out in accordance with a technical method well known to those skilled in the art, and there is no particular limitation in this application. In the present application, the voltage of the electrostatic spinning is 0.1kV to 30kV, and more specifically, the voltage of the electrostatic spinning is 5 to 20kV. In the present application, the substrate is selected from PTFE, PET, PP, PE, a proton exchange membrane or a gas diffusion layer. When the substrate is selected from a material other than a proton exchange membrane, after preparing the cathode or anode catalyst layer, the cathode or anode catalyst layer is compounded to both sides of the proton exchange membrane by means of hot pressing or transfer printing. In a specific embodiment, the substrate is selected from a proton exchange membrane.

[0058] Finally, the present application is to coat the other side of the proton exchange membrane with the first anode catalytic slurry, dry it, and obtain the first anode catalytic layer; or coat the other side of the proton exchange membrane with the second anode catalytic slurry, dry it, and then use the first resin spinning solution for electrostatic spinning to obtain a composite first anode catalytic layer; or coat the third anode catalytic slurry on one side of the proton exchange membrane, dry it, and then use the second resin spinning solution for electrostatic spinning, dry it, and then coat it with the fourth anode catalytic slurry, dry it, and obtain a composite second anode catalytic layer. The preparation method of the anode catalytic layer and the composite anode catalytic layer is the same as that of the cathode catalytic layer, and will not be described in detail here. The coating can be selected from ultrasonic spraying, slit coating, electrostatic spraying, doctor blade coating, comma coating, inkjet printing or screen printing; the drying can be selected from flat plate heat treatment, oven heat treatment, infrared heat treatment or hot air gun drying.

[0059] In the composite electrode structure provided by the present invention, the introduction of a resin fiber layer with high proton conductivity can greatly enhance the proton conductivity of the catalytic layer, thereby achieving the purpose of improving electrode performance.

[0060] In order to further understand the present invention, the composite electrode structure and the preparation method thereof provided by the present invention are described in detail below in conjunction with the embodiments. The protection scope of the present invention is not limited by the following embodiments.

[0061] Example 1 25cm 2 Traditional catalytic layer

[0062] Preparation of cathode catalyst layer: Weigh 2.7 g of cathode catalyst Pt / C (57 wt% Pt), add 30.07 g of water and 5.87 g of ethanol as solvent, and then add 4.57 g of 20 wt% perfluorosulfonic acid resin as polymer electrolyte, and prepare cathode catalyst slurry by mixing; on one side of the proton exchange membrane, on an area of 7×7 cm, 0.15 mg Pt / cm 2 The cathode catalyst slurry was sprayed and dried at 90°C;

[0063] Preparation of anode catalyst layer: Weigh 2g of anode catalyst Pt / C (50wt% Pt), add 19.5g of water and 6.5g of ethanol as solvent, and then add 4.5g of 20wt% perfluorosulfonic acid resin as polymer electrolyte, and prepare anode catalyst slurry by mixing; Pt / cm 2 The loaded material is sprayed onto the other side of the proton exchange membrane and dried to prepare a membrane electrode.

[0064] The membrane electrode prepared in this example was installed in a single cell, and polarization performance and AC impedance test were performed at 80° C. and 100% RH.

[0065] Example 2 25cm 2 Two-layer structure - fiber surface modified membrane / traditional catalytic layer

[0066] Preparation of electrospinning solution: Weigh 1.2 g of perfluorosulfonic acid resin particles, add 18.8 g of DMF solvent, and then add 0.3 g of 600,000 molecular weight PEO polymer, and stir at 65°C for 24 h;

[0067] Preparation of cathode catalyst slurry: 2.7 g of cathode catalyst Pt / C (57 wt% Pt) was weighed, 30.07 g of water and 5.87 g of ethanol were added as solvent, and 4.57 g of 20 wt% perfluorosulfonic acid resin as polymer electrolyte was added, and cathode catalyst slurry was prepared by mixing;

[0068] Preparation of cathode catalyst layer: On one side of the proton exchange membrane, in an area of 7×7 cm, the resin spinning solution was spun at 27 kV for 5 min to form a resin fiber layer; after heat treatment at 140 ° C for 30 min, the resin fiber layer was finally prepared according to 0.15 mg Pt / cm 2The cathode catalyst slurry is sprayed on the surface of the resin fiber layer and dried at a temperature of 90° C. to prepare a cathode catalyst layer;

[0069] Preparation of anode catalyst layer: Weigh 2g of anode catalyst Pt / C (50wt% Pt), add 19.5g of water and 6.5g of ethanol as solvent, and then add 4.5g of 20wt% perfluorosulfonic acid resin as polymer electrolyte, and prepare anode catalyst slurry by mixing; Pt / cm 2 The load is sprayed onto the other side of the proton exchange membrane to prepare a membrane electrode.

[0070] The membrane electrode prepared in this example was installed in a single cell, and polarization performance and AC impedance testing were performed at 80° C. and 100% RH.

[0071] Example 3 25cm 2 Three-layer structure - traditional catalytic layer / resin fiber layer / traditional catalytic layer

[0072] Preparation of cathode catalyst layer: Weigh 2.7g of cathode catalyst Pt / C (57wt% Pt), add 30.07g of water and 5.87g of ethanol as solvent, then add 4.57g of 20wt% perfluorosulfonic acid resin as polymer electrolyte, and prepare cathode catalyst slurry by mixing; weigh 1.2g of perfluorosulfonic acid resin particles, add 18.8g of methanol solvent, then add 0.3g of 600,000 molecular weight PEO polymer, and stir at 40°C for 24h; on one side of the proton exchange membrane, on a 7×7cm area, according to 0.05mg Pt / cm 2 The cathode catalyst slurry was sprayed with a certain amount of loading and dried at a temperature of 90°C to prepare a catalyst layer 1; then, the resin spinning solution was subjected to resin spinning at 27 kV for 5 minutes to form a resin spinning layer; finally, 0.1 mg Pt / cm 2 The cathode catalyst slurry is sprayed on the surface of the resin fiber layer and dried at a temperature of 90° C. to prepare a catalyst layer 2;

[0073] Preparation of anode catalyst layer: Weigh 2g of anode catalyst Pt / C (50wt% Pt), add 19.5g of water and 6.5g of ethanol as solvent, add 4.5g of 20wt% perfluorosulfonic acid resin as polymer electrolyte, and prepare anode catalyst slurry by mixing; Pt / cm 2 The load is sprayed onto the other side of the proton exchange membrane to prepare a membrane electrode. The structural diagram of the membrane electrode is shown in Figure 1 shown.

[0074] The membrane electrode prepared in this example was installed in a single cell, and polarization performance and AC impedance test were performed at 80° C. and 100% RH.

[0075] Example 4 300cm 2 Traditional catalytic layer

[0076] Preparation of cathode catalyst layer: 2.7 g of cathode catalyst Pt / C (57 wt% Pt) was weighed, 30.07 g of water and 5.87 g of ethanol were added as solvent, and 4.57 g of 20 wt% perfluorosulfonic acid resin was added as polymer electrolyte to prepare cathode catalyst slurry by mixing; on one side of the proton exchange membrane, 300 cm 2 In the region, according to 0.15mg Pt / cm 2 The cathode catalyst slurry was sprayed and dried at 90°C;

[0077] Preparation of anode catalyst layer: Weigh 2g of anode catalyst Pt / C (50wt% Pt), add 19.5g of water and 6.5g of ethanol as solvent, and then add 4.5g of 20wt% perfluorosulfonic acid resin as polymer electrolyte, and prepare anode catalyst slurry by mixing; Pt / cm 2 The loaded material is sprayed onto the other side of the proton exchange membrane and dried to prepare a membrane electrode.

[0078] The membrane electrode prepared in this example was installed in a full-size single cell fixture to perform polarization curve testing.

[0079] Example 5 300cm 2 Three-layer structure - traditional catalytic layer / resin fiber layer / traditional catalytic layer

[0080] Preparation of cathode catalyst layer: Weigh 2.7g of cathode catalyst Pt / C (57wt% Pt), add 30.07g of water and 5.87g of ethanol as solvent, then add 4.57g of 20wt% perfluorosulfonic acid resin as polymer electrolyte, and prepare cathode catalyst slurry by mixing; weigh 1.2g of perfluorosulfonic acid resin particles, add 18.8g of N,N-dimethylformamide (DMF) solvent, then add 0.3g of 600,000 molecular weight PEO polymer, and stir at 65°C for 24h; on one side of the proton exchange membrane, 300cm 2 In the region, according to 0.05mg Pt / cm 2 The cathode catalyst slurry was sprayed with a certain amount of loading and dried at a temperature of 90°C to prepare a catalyst layer 1; then, the resin spinning solution was subjected to resin spinning at 10 kV for 5 minutes to form a resin fiber layer; finally, 0.05 mg Pt / cm 2The cathode catalyst slurry is sprayed on the surface of the resin fiber layer and dried at a temperature of 90° C. to prepare a catalyst layer 2;

[0081] Preparation of anode catalyst layer: Weigh 2g of anode catalyst Pt / C (50wt% Pt), add 19.5g of water and 6.5g of ethanol as solvent, add 4.5g of 20wt% perfluorosulfonic acid resin as polymer electrolyte, and prepare anode catalyst slurry by mixing; Pt / cm 2 The load is sprayed onto the other side of the proton exchange membrane to prepare a membrane electrode.

[0082] The membrane electrode prepared in this example was installed in a full-size single cell fixture to perform polarization curve testing.

[0083] Example 6 300cm 2 Five-layer structure - traditional catalytic layer / resin fiber layer / traditional catalytic layer / resin fiber layer / traditional catalytic layer

[0084] Preparation of cathode catalyst layer: Weigh 2.7g of cathode catalyst Pt / C (57wt% Pt), add 30.07g of water and 5.87g of ethanol as solvent, then add 4.57g of 20wt% perfluorosulfonic acid resin as polymer electrolyte, and prepare cathode catalyst slurry by mixing; weigh 1.2g of perfluorosulfonic acid resin particles, add 18.8g of DMF solvent, then add 0.3g of 600,000 molecular weight PEO polymer, and stir at 65°C for 24h; on one side of the proton exchange membrane, 300cm 2 In the region, according to 0.05mg Pt / cm 2 The cathode catalyst slurry was sprayed with a certain amount of loading and dried at a temperature of 90°C to prepare a catalyst layer 1; then, the resin spinning solution was subjected to resin spinning at 10 kV for 5 minutes to form a resin fiber layer 1; and then 0.05 mg Pt / cm 2 The cathode catalyst slurry was sprayed on the surface of the resin fiber layer and dried at 90°C to prepare the catalyst layer 2; the resin spinning solution was then spun at 10 kV for 5 min to form the resin fiber layer 2; and finally 0.05 mg Pt / cm 2 The cathode catalyst slurry is sprayed on the surface of the resin fiber layer and dried at a temperature of 90° C. to prepare a catalyst layer 3;

[0085] Preparation of anode catalyst layer: Weigh 2g of anode catalyst Pt / C (50wt% Pt), add 19.5g of water and 6.5g of ethanol as solvent, add 4.5g of 20wt% perfluorosulfonic acid resin as polymer electrolyte, and prepare anode catalyst slurry by mixing; Pt / cm 2 The load is sprayed onto the other side of the proton exchange membrane to prepare a membrane electrode.

[0086] The prepared membrane electrode was placed in a full-size single-cell fixture for polarization curve testing.

[0087] Figure 2 25cm prepared in Examples 1 to 3 2 Polarization curve of membrane electrode; test conditions are single cell 80℃, relative humidity 100% / 100% (Ca / An), Air / H2 stoichiometric ratio 2 / 2 (Ca / An), back pressure 150KPa / 150KPa (Ca / An)). Figure 2 It can be seen that the structure of the membrane electrode provided by the present invention exhibits excellent mass transfer capability in a large current density range, and the performance ranking is: Example 3> Example 2> Example 1; in addition, the HFR of Example 3 is lower than that of the traditional catalytic layer (Example 1); therefore, the three-layer electrode structure of the present invention has relatively excellent polarization performance, and the performance of the resin fiber in the catalytic layer interlayer is better than that of the single-layer catalytic layer structure on the resin fiber modified proton exchange membrane.

[0088] Figure 3 The AC impedance curve data of the membrane electrode prepared in Example 1 and Example 3 under H2-N2 conditions; the test conditions are: single cell 80℃, relative humidity 100% / 100% (Ca / An), N2 / H2 flow rate 0.2 / 0.2L / min (Ca / An), 0.1Hz-15kHz; Figure 3 It can be seen that the order of the proton transmission resistance of the catalytic layer is: Example 3 < Example 1, which once again proves that the insertion of the resin fiber layer improves the proton transmission capacity of the entire catalytic layer.

[0089] Figure 4 The polarization curves of the membrane electrodes prepared in Examples 4 to 6 were obtained under the following test conditions: no humidification at the cathode and 25-35% RH at the anode. Figure 4 It can be seen that the performance of the membrane electrode structure provided by the present invention in the large current density area is ranked as Example 6 > Example 5 > Example 4, which means that the performance of the 5-layer structure is better than that of the 3-layer structure and the traditional catalytic layer; the insertion of the resin fiber layer greatly improves the proton transport capacity of the catalytic layer under low humidification conditions, and the HFR of the 5-layer membrane electrode is lower than that of the traditional catalytic layer, which can also illustrate this feature.

[0090] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0091] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A composite electrode structure, comprising a proton exchange membrane, an anode catalyst layer composited on one side of the proton exchange membrane, and a cathode catalyst layer composited on the other side of the proton exchange membrane; the anode catalyst layer is one or two of a first anode catalyst layer, a third anode catalyst layer stacked in sequence, a second resin fiber layer, and a fourth anode catalyst layer; the cathode catalyst layer is one or two of a first cathode catalyst layer, a third cathode catalyst layer stacked in sequence, a fourth resin fiber layer, and a fourth cathode catalyst layer; the first anode catalyst layer and the first cathode catalyst layer are not selected at the same time; the second resin fiber layer and the fourth resin fiber layer are both obtained by electrospinning from a resin spinning solution.

2. The composite electrode structure according to claim 1, characterized in that: The Pt loading in the first anode catalyst layer, the third anode catalyst layer, the fourth anode catalyst layer, the first cathode catalyst layer, the third cathode catalyst layer, and the fourth cathode catalyst layer is independently 0.01 to 0.5 mg / cm 2 .

3. The composite electrode structure according to claim 1, characterized in that: The thickness of the second resin fiber layer and the fourth resin fiber layer are independently 0.1 to 10 μm.

4. The composite electrode structure according to claim 1, characterized in that: The number of repeated layers of the sequentially stacked third anode catalyst layer, the second resin fiber layer and the fourth anode catalyst layer is independently ≥1, and the number of repeated layers of the sequentially stacked third cathode catalyst layer, the fourth resin fiber layer and the fourth cathode catalyst layer is independently ≥1.

5. The method for preparing the composite electrode structure according to claim 1, comprising the following steps: A) mixing a cathode catalyst, a polymer electrolyte, and a solvent to obtain a cathode catalyst slurry; preparing a first cathode catalyst slurry, a third cathode catalyst slurry, and a fourth cathode catalyst slurry respectively according to the above method; The second resin, the second polymer carrier and the solvent are mixed to obtain a second resin spinning solution; and a fourth resin spinning solution is prepared according to the above method; Mixing an anode catalyst, a polymer electrolyte and a solvent to obtain an anode catalyst slurry; preparing a first anode catalyst slurry, a third anode catalyst slurry and a fourth anode catalyst slurry respectively according to the above method; B) coating the first cathode catalyst slurry on one side of a proton exchange membrane and drying the slurry to obtain a first cathode catalyst layer; and / or coating the third cathode catalyst slurry on one side of the proton exchange membrane, drying it, then electrospinning it with a fourth resin spinning solution, drying it, then coating it with a fourth cathode catalyst slurry, and drying it; or, B') coating the first cathode catalyst slurry on one side of the substrate, drying the slurry to obtain a first cathode catalyst layer, and transferring the first cathode catalyst layer to the surface of the proton exchange membrane; and / or coating the third cathode catalyst slurry on one side of the proton exchange membrane, drying it, and then electrospinning it with a fourth resin spinning solution, drying it, and then coating it with a fourth cathode catalyst slurry, drying it, to obtain a second composite cathode layer, and transferring the second composite cathode layer to the surface of the proton exchange membrane; C) coating the first anode catalyst slurry on the other side of the proton exchange membrane and drying to obtain a first anode catalyst layer; and / or coating the third anode catalyst slurry on one side of the proton exchange membrane, drying it, then electrospinning it with a second resin spinning solution, drying it, then coating it with a fourth anode catalyst slurry, and drying it; The first anode catalyst layer and the first cathode catalyst layer are not selected at the same time.

6. The preparation method according to claim 5, characterized in that The first anode catalyst, the third anode catalyst layer, the fourth anode catalyst layer, the first cathode catalyst layer, the third cathode catalyst layer, and the fourth cathode catalyst layer are independently selected from platinum-carbon catalysts, platinum-based alloy catalysts, or non-precious metal catalysts.

7. The preparation method according to claim 5, characterized in that The polymer electrolyte in the first anode catalyst slurry, the third anode catalyst slurry and the fourth anode catalyst slurry, the polymer electrolyte in the first cathode catalyst slurry, the third cathode catalyst slurry and the fourth cathode catalyst slurry, and the resin in the second resin spinning solution and the fourth resin spinning solution are independently selected from one or more of long-chain branched perfluorosulfonic acid resin, short-chain branched perfluorosulfonic acid resin, sulfonated polystyrene, sulfonated polyarylethersulfone, sulfonated polyetheretherketone, polyvinylidene fluoride, polytetrafluoroethylene and tetrafluoroethylene-co-hexafluoroethylene; the polymer carrier is selected from one or more of polyacrylic acid, polyethylene oxide, polytetrafluoroethylene, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetate, polyacrylonitrile and polymethacrylate.

8. The preparation method according to claim 5 or 7, characterized in that The content of the polymer carrier in the second resin spinning solution and the fourth resin spinning solution is 0.01-50 wt %.

9. The preparation method according to claim 8, characterized in that The voltage of the electrospinning is 0.1 kV to 30 kV.

10. The preparation method according to any one of claims 5 to 7 and 9, characterized in that: In step B) and step C), the coating is independently selected from ultrasonic spraying, electrostatic spraying, slit coating, doctor blade coating, comma coating, inkjet printing or screen printing; and the drying is independently selected from flatbed heat treatment, oven heat treatment, infrared heat treatment or hot air gun drying.

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