CN116093345A - A nanofiber catalytic layer membrane and fuel cell membrane electrode based on electrospinning and its preparation method - Google Patents

Abstract

The invention provides a nanofiber catalytic layer membrane based on electrostatic spinning, a fuel cell membrane electrode and a preparation method thereof; the catalytic layer film is prepared by electrostatic spinning of catalyst spinning slurry; the catalyst spinning slurry comprises resin, a catalyst, a polymer carrier and a solvent; the polymer carrier is one or more selected from polyacrylic acid, polyethylene oxide, polytetrafluoroethylene, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetate, polyacrylonitrile and polymethacrylate. The catalytic layer film is prepared by taking a polymer carrier as one of raw materials and combining electrostatic spinning, and has certain strength and can be independently formed into a film; the intermediate treatment is facilitated, and the proton exchange membrane is flexibly matched with the proton exchange membrane; the membrane electrode compounded with the proton exchange membrane has higher polarization performance.

Description

A nanofiber catalytic layer membrane and fuel cell membrane electrode based on electrospinning and its preparation method

technical field

The invention belongs to the technical field of membrane electrodes, and in particular relates to a nanofiber catalytic layer membrane based on electrospinning, a fuel cell membrane electrode and a preparation method thereof.

Background technique

In today's environment where the world's energy structure is deeply adjusted due to accelerated climate change and constant constraints on energy resources, hydrogen energy has become one of the recognized strategic directions and has attracted much attention. Since the fuel cell does not need to go through the Carnot cycle of the heat engine, it has higher efficiency, and at the same time, there is no emission during use and is environmentally friendly, so the fuel cell is one of the important application directions of hydrogen energy. Fuel cells are in the initial rising stage of commercial application, facing problems such as short lifespan and high cost. However, the preparation process of its core component, the membrane electrode, is relatively complicated, and its performance, production efficiency, and yield rate are all crucial to the cost and life of the fuel cell.

At present, the continuous production process of membrane electrodes is based on processes such as spray coating, scrape coating and screen printing to directly prepare the catalytic layer on the proton exchange membrane to form a membrane electrode, or prepare the catalytic layer on the surface of other substrate materials, and then use thermal transfer printing and other processes The catalytic layer was transferred to the proton exchange membrane to prepare the membrane electrode.

In the patent "A Process Method for Producing Membrane Electrodes", through thermal transfer printing process, thermal composite process, carbon paper bonding process and hot pressing process, although this method can realize continuous automatic production, the transfer process The damage to the proton exchange membrane is relatively large, which is not conducive to the durability of the membrane electrode. The patent "A Membrane-Membrane Electrode Integrated Preparation Method for Fuel Cell" proposes to prepare proton exchange membrane and membrane electrode from resin solution. This method has simple process and is easy to realize large-scale production. After that, if the membrane electrode is prepared directly without product yield verification, there may be a problem of low product yield.

Contents of the invention

In view of this, the object of the present invention is to provide a nanofiber catalytic layer membrane based on electrospinning and a fuel cell membrane electrode and a preparation method thereof. The catalytic layer membrane can be rolled separately; Advantages such as the transmission path can achieve high mass transfer, and the prepared membrane electrode has high performance.

The invention provides a nanofiber catalytic layer membrane based on electrospinning, which is prepared by electrospinning catalyst spinning slurry;

The catalyst spinning slurry includes resin, catalyst, polymer carrier and solvent;

The polymer carrier is selected from one or more of polyacrylic acid, polyethylene oxide, polytetrafluoroethylene, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetate, polyacrylonitrile and polymethacrylate.

In the prior art, the catalytic layer is directly formed on the proton exchange membrane, or on materials such as PTFE. Since materials such as proton exchange membrane or PTFE are attached to the catalytic layer, the temperature for further high-temperature treatment of the catalytic layer is limited. In the present invention, since the catalytic layer can be formed into a film independently, it is not limited by post-treatment temperature and other conditions. The nanofiber catalytic layer film based on electrospinning provided by the present invention can be peeled off separately to form a film (see FIG. 1 ); it proves the feasibility of peeling off the catalytic layer film from the base material.

In the present invention, the resin is selected from long-chain branched perfluorosulfonic acid resin, short-chain branched perfluorosulfonic acid resin, sulfonated polystyrene, sulfonated polyarylether sulfone, sulfonated polyether ether ketone, One or more of polyvinylidene fluoride, polytetrafluoroethylene and tetrafluoroethylene-co-hexafluoroethylene;

The solvent is selected from one or more of water, isopropanol, n-propanol, ethanol, methanol, N,N-dimethylformamide, dimethylsulfoxide and chloroform;

The catalyst is selected from one or more of platinum-carbon catalysts, platinum-based alloy catalysts and non-noble metal catalysts.

In the present invention, the mass ratio of the resin, catalyst, polymer carrier and solvent is (0.1-5): (0.1-5): (0.01-2): (1-60).

In the present invention, the catalyst spinning slurry is prepared by mixing resin, catalyst, polymer carrier and solvent;

The mixing method is selected from one or more of ultrasonic, bead milling, stirring and homogenization.

In the present invention, the electrospinning voltage of the catalyst spinning slurry is 0.1-100kv, the distance between the nozzle and the receiving substrate is 1-20cm, the temperature is 15-80°C, and the humidity is 10%RH-80RH%;

The needles are selected from needle showers, needleless showers or microporous showers.

In the present invention, the receiving substrate is selected from release paper, silicone oil paper or aluminum foil.

In the present invention, the loading capacity of the cathode nanofiber catalytic layer membrane is 0.05-1 mg _Pt /cm ² ;

The loading capacity of the anode nanofiber catalytic layer membrane is 0.05-1 mg _Pt /cm ² .

The nanofiber catalytic layer film of the present invention is made on the base material by electrospinning; as shown in Figure 2, the base material is placed on the material shaft A, pulled by the roller pressing shaft a, and the base material advances according to the set speed, the The speed is mainly set according to the loading capacity of the catalytic layer; the spinning equipment spins out of the material shaft B, and the catalytic layer film and the substrate material are peeled off at the roller pressing shaft c, and the substrate material is wound to the material shaft C through the shaft d; the catalytic layer The film passes through the axis e, and then winds up to the material axis D through the post-treatment process to prepare the catalytic layer film.

The catalytic layer membrane includes catalyst, resin and polymer carrier (PAA, etc.), and is woven into a catalytic layer through fibers, so it has a certain strength and can be rolled separately, which is beneficial to the separate post-treatment of the catalytic layer. In the present invention, post-treatment is also included after the electrospinning of the catalyst spinning slurry;

The post-treatment includes hot rolling, flat plate heating, infrared heating or blast oven heating.

The invention provides a fuel cell membrane electrode, comprising a cathode nanofiber catalyst layer membrane, a proton exchange membrane and an anode nanofiber catalyst layer membrane;

Both the cathode nanofiber catalyst layer membrane and the anode nanofiber catalyst layer membrane are nanofiber catalyst layer membranes described in the above technical solution.

The present invention provides a method for preparing a fuel cell membrane electrode described in the above technical solution, comprising the following steps:

Composite the anode nanofiber catalyst layer membrane, the proton exchange membrane and the cathode nanofiber catalyst layer membrane to obtain a membrane electrode;

The compounding pressure is 0.1-10MPa, and the compounding temperature is 10-140°C.

As shown in Figure 3, in a specific embodiment, the preparation method of the fuel cell membrane electrode includes: placing the proton exchange membrane on the material axis E, stripping the back film of the proton exchange membrane and collecting it on the material axis F, and the proton exchange membrane Traction by the roller pressing shaft f; the anode catalytic layer film and the cathode catalytic layer film are respectively placed on the material axis G and the material axis H, and are respectively pulled by the roller pressing axis h and the rolling axis i; the proton exchange membrane, the anode nanofiber catalytic layer membrane and the cathode nanofiber The catalytic layer film is prepared by compounding the roll pressing axis j and the material axis k to obtain the CCM product, which is combined with the back film and collected to the material axis I; the composite process at the material axis j and the material axis k can control parameters such as pressure and temperature.

Referring to Fig. 4: in the specific embodiment, the preparation method of the fuel cell membrane electrode specifically includes S1: preparation of catalyst spinning slurry; S2: preparation process of nanofiber catalytic layer membrane; S3: CCM preparation-nanofiber catalytic layer membrane Composite process with proton exchange membrane. The production process of the above-mentioned membrane electrode is flexible and the quality is controllable, which can reduce the cost of CCM preparation and improve the yield rate; the composite process with the proton exchange membrane is relatively mild, with less damage to it, and to a certain extent alleviates the effects of electrospinning. Process inefficiencies.

The nanofiber catalytic layer membrane prepared by electrospinning in the present invention has the advantages of through-hole structure and short transmission path along the fiber, which can realize high mass transfer, and the membrane electrode has high performance, such as polarization performance; it can be rolled into a single product as a product , which is conducive to the intermediate treatment of the catalytic layer and the flexible matching with the proton exchange membrane; realizes the separate production of the catalytic layer membrane and the proton exchange membrane, and accelerates the production efficiency and flexibility of the catalyst coated membrane (CCM). In addition, the mild composite process of the catalytic layer membrane and the proton exchange membrane can solve the problem of damage to the proton exchange membrane caused by the thermal transfer process.

Description of drawings

Fig. 1 is the schematic diagram that catalytic layer film is peeled off separately;

Fig. 2 is the preparation flow diagram of catalytic layer film in specific embodiment;

Fig. 3 is the technological process of composite film-forming electrode of catalyst layer membrane and proton exchange membrane in the specific embodiment;

Fig. 4 is the technological process of the fuel cell membrane electrode based on electrospinning in the specific embodiment of the present invention;

Fig. 5 compares the electrochemically active area (ECSA) of the membrane electrode prepared by the embodiment of the present invention and comparative example;

Fig. 6 is the battery test performance results of the membrane electrodes prepared in the examples and comparative examples of the present invention.

Detailed ways

In order to further illustrate the present invention, a kind of electrospinning-based nanofiber catalytic layer film and fuel cell membrane electrode and preparation method thereof provided by the present invention are described in detail below in conjunction with the examples, but they cannot be interpreted as limiting the protection scope of the present invention. limit.

Comparative example 1

Preparation of traditional catalytic layer

A membrane electrode with a cathode loading of 0.15 mg _Pt /cm ² and an anode loading of 0.05 mg _Pt /cm ² was prepared by ultrasonic spraying. The prepared membrane electrode was loaded into a standard single cell and tested under H ₂ /Air at 80°C and 100% RH polarization performance.

Example 1

Cathodic catalyst layer film preparation: Weigh 2.7g of cathode catalyst Pt/C (57wt%Pt), add 9g of water and 9g of isopropanol as solvent, add 4.57g of 20wt% perfluorosulfonic acid resin, and sonicate for 1h. Then add 0.5g of PAA with a molecular weight of 450,000, and stir for 48h; prepare 0.15mg of PAA by electrospinning (voltage 30kV, flow rate 1mL/h, distance between needle and receiver 10cm) on one side of the proton exchange membrane, on a 7×7cm area. _Pt / ^cm2 cathode catalytic layer film;

Preparation of the anode catalyst layer film: Weigh 2g of the anode catalyst Pt/C (50wt%Pt), add 7g of water and 7g of isopropanol as solvents, add 4.5g of 20wt% perfluorosulfonic acid resin, and sonicate for 1h. Then add 0.5g of PAA with a molecular weight of 450,000, and stir for 48h; prepare 0.05mg by electrospinning (voltage 25kV, flow rate 0.5mL/h, distance between needle and receiver 10cm) on one side of the proton exchange membrane, on a 7×7cm area. _Pt /cm ² anode catalyst layer film;

The prepared membrane electrode was loaded into a standard single cell, and the polarization performance under H ₂ /Air was tested at 80°C and 100% RH.

Example 2

Heat-treated catalytic layer film preparation:

Cathodic catalyst layer film preparation: Weigh 2.7g of cathode catalyst Pt/C (57wt%Pt), add 9g of water and 9g of isopropanol as solvent, add 4.57g of 20wt% perfluorosulfonic acid resin, and sonicate for 1h. Then add 0.5g PAA with a molecular weight of 450,000, and stir for 48h; prepare 0.15mg _Pt / ^cm2 by electrospinning (voltage 30kV, flow rate 1mL/h, distance between needle and receiver 10cm) on a 7×7cm release paper For the cathode catalytic layer film, peel off the catalytic layer film and place it in an oven for heat treatment at 150°C for 20 minutes;

Preparation of the anode catalyst layer film: Weigh 2g of the anode catalyst Pt/C (50wt%Pt), add 7g of water and 7g of isopropanol as solvents, add 4.5g of 20wt% perfluorosulfonic acid resin, and sonicate for 1h. Then add 0.5g of PAA with a molecular weight of 450,000 and stir for 48h; prepare a 0.05mg _Pt / ^cm2 anode by electrospinning (voltage 25kV, flow rate 0.5mL/h, needle and receiver distance 10cm) on a 7×7cm release paper Catalytic layer film, peel off the catalytic layer film, and place it in an oven for heat treatment at 150°C for 20 minutes;

The anode catalyst layer membrane, the proton exchange membrane, and the anode catalyst layer membrane are hot-pressed and composited according to the process shown in Figure 3 to obtain a membrane electrode;

The prepared membrane electrode was loaded into a standard battery, and the polarization performance under H ₂ /Air was tested at 80° C. and 100% RH.

Fig. 5 compares the electrochemically active area (ECSA) of the membrane electrode prepared by the embodiment of the present invention and comparative example, embodiment 2>embodiment 1>comparative example 1, illustrates that the utilization rate of the catalyst in the nanofiber membrane catalyst layer is higher than that of the pair The traditional catalytic layer in ratio 1, and the utilization rate of the catalyst after the hot-pressing process is also significantly improved, indicating that the hot-pressing process promotes the structural rearrangement between fibers, and high temperature is conducive to the uniform distribution of resin on the surface of the catalyst, which can improve performance;

Figure 6 is a comparison of the battery performance polarization curves of the membrane electrodes prepared in the examples of the present invention and comparative examples. The membrane electrodes prepared in Example ² reached 0.637V at 2000mA/cm 2 ² and reached 0.597V, while the membrane electrode prepared in Comparative Example 1 reached 0.568V at 2000mA/cm ² ; it can be seen that the membrane electrode in Example 2 has better mass transfer capacity than the traditional membrane electrode in the high density area , so it shows higher voltage performance at the same current density.

As can be seen from the above examples, the present invention provides a nanofiber catalytic layer film based on electrospinning, which is prepared by electrospinning of catalyst spinning slurry; the catalyst spinning slurry includes resin, catalyst, polymer carrier and solvent; the polymer carrier is selected from one or more of polyacrylic acid, polyethylene oxide, polytetrafluoroethylene, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetate, polyacrylonitrile and polymethacrylate Various. The catalytic layer membrane is made of polymer carrier as one of the raw materials, combined with electrospinning, which has a certain strength and can be formed into a film alone; it is conducive to its intermediate treatment and flexible matching with the proton exchange membrane; Membrane electrodes have high polarizability.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (10)

1. A nanofiber catalytic layer membrane based on electrostatic spinning is prepared by electrostatic spinning of catalyst spinning slurry;

the catalyst spinning slurry comprises resin, a catalyst, a polymer carrier and a solvent;

the polymer carrier is one or more selected from polyacrylic acid, polyethylene oxide, polytetrafluoroethylene, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetate, polyacrylonitrile and polymethacrylate.

2. The nanofiber catalytic layer membrane according to claim 1, wherein the resin is selected from one or more of long-chain-type perfluorosulfonic acid resin, short-chain-type perfluorosulfonic acid resin, sulfonated polystyrene, sulfonated poly (arylene ether sulfone), sulfonated poly (ether ketone), polyvinylidene fluoride, polytetrafluoroethylene and tetrafluoroethylene-co-hexafluoroethylene;

the solvent is selected from one or more of water, isopropanol, N-propanol, ethanol, methanol, N-dimethylformamide, dimethyl sulfoxide and chloroform;

the catalyst is selected from one or more of a platinum carbon catalyst, a platinum-based alloy catalyst and a non-noble metal catalyst.

3. The nanofiber catalytic layer membrane according to claim 1, wherein the mass ratio of resin, catalyst, polymer carrier and solvent is (0.1-5): (0.1-5): (0.01-2): (1-60).

4. The fuel cell membrane electrode based on electrospinning according to claim 1, wherein the catalyst spinning dope is prepared by mixing a resin, a catalyst, a polymer carrier and a solvent;

the mixing mode is selected from one or more of ultrasonic, bead grinding, stirring and homogenizing.

5. The nanofiber catalytic layer membrane according to claim 1, wherein the voltage during the electrostatic spinning of the catalyst spinning slurry is 0.1-100 kv, the distance between the spray head and the receiving substrate is 1-20 cm, the temperature is 15-80 ℃, and the humidity is 10% -RH-80 RH%;

the needle is selected from needle type spray head, needleless spray head or microporous spray head.

6. The nanofiber catalytic layer membrane according to claim 5, wherein the receiving substrate is selected from release paper, silicone paper or aluminum foil.

7. The nanofiber catalytic layer membrane according to claim 1, wherein the loading of the cathodic nanofiber catalytic layer membrane is 0.05-1 mg _Pt /cm ² ；

The carrying capacity of the anode nanofiber catalytic layer membrane is 0.05-1 mg _Pt /cm ² 。

8. The nanofiber catalytic layer membrane of claim 1, wherein the catalyst spin slurry further comprises post-treatment after electrospinning;

the post-treatment includes hot rolling, flat plate heating, infrared heating or forced air oven heating.

9. The fuel cell membrane electrode is characterized by comprising a cathode nanofiber catalytic layer membrane, a proton exchange membrane and an anode nanofiber catalytic layer membrane;

the cathode nanofiber catalytic layer membrane and the anode nanofiber catalytic layer membrane are both nanofiber catalytic layer membranes according to claim 1.

10. A method of preparing the fuel cell membrane electrode according to claim 9 comprising the steps of:

compounding the anode nanofiber catalytic layer membrane, the proton exchange membrane and the cathode nanofiber catalytic layer membrane to obtain a membrane electrode;

the pressure of the compounding is 0.1-10 MPa, and the temperature of the compounding is 10-140 ℃.

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