A gradient catalytic layer composite membrane electrode and its production apparatus

Abstract

This invention proposes a gradient catalyst layer composite membrane electrode and its production apparatus, comprising a proton exchange membrane and gradient catalyst layers with increasing porosity on both sides of the proton exchange membrane. By setting gradient catalyst layers on the proton exchange membrane with gradually increasing porosity from the inside out, this invention constructs a highly efficient gas-mass electron transport channel, achieving a dual improvement in fuel cell performance and durability.

Description

Technical Field

[0001] This utility model relates to the field of membrane electrode technology, and in particular to a gradient catalytic layer composite membrane electrode and its production apparatus. Background Technology

[0002] Traditional membrane electrodes suffer from problems such as high precious metal content, low proton conduction efficiency, and insufficient durability. For example, the platinum loading of the catalyst layer prepared by spray coating process is as high as 0.2 mg / cm², and catalyst agglomeration is prone to occur; stress concentration at the proton exchange membrane interface leads to significant performance degradation after thermal cycling; and the gas diffusion layer has poor liquid water management capabilities, which can easily cause electrode flooding.

[0003] Existing technology, such as the utility model patent CN221080062U published on June 4, 2024, discloses a membrane electrode including a frame, a high-temperature proton exchange membrane, a diffuser plate, a catalyst layer, and four vent holes. The middle portion of the frame is hollowed out. The high-temperature proton exchange membrane is fixedly connected to the hollowed-out portion of the frame. The diffuser plates are located on both sides of the high-temperature proton exchange membrane, and a catalyst material is coated between the high-temperature proton exchange membrane and the diffuser plates on both sides. The four vent holes are symmetrically arranged at the edges of the frame. The frame has a double-layer molded structure, and the thickness of the frame is greater than the thickness of the diffuser plate. Although this patent proposes a molded frame design, it does not solve the problems of gradient mass transfer and interface stability in the catalyst layer. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a gradient catalytic layer composite membrane electrode and its production apparatus, which solves the problem of unresolved gradient mass transfer and interface stability in the existing membrane electrode technology.

[0005] To achieve the above objectives, the technical solution of this utility model is implemented as follows:

[0006] A gradient catalyst layer composite membrane electrode includes a proton exchange membrane with a gradient catalyst layer on both sides of the proton exchange membrane, the porosity of which increases from the inside to the outside. This invention, by setting a gradient catalyst layer on the proton exchange membrane with a gradient increase in porosity from the inside to the outside, constructs a highly efficient gas-mass electron transport channel, achieving a dual improvement in fuel cell performance and durability.

[0007] Furthermore, in order to directionally deposit platinum particles, the gradient catalytic layer includes a first nanoscale platinum-carbon layer formed by magnetron sputtering.

[0008] Furthermore, in order to precisely form the double-sided catalytic layer, the gradient catalytic layer also includes a second nanoscale platinum-carbon layer formed by transfer printing, the second nanoscale platinum-carbon layer being located outside the first nanoscale platinum-carbon layer.

[0009] Furthermore, in order to form a gradient catalytic layer, the density of the first nanoscale platinum carbon layer is greater than that of the second nanoscale platinum carbon layer.

[0010] Furthermore, in order to form a tighter interface when the catalyst layer comes into contact with the proton exchange membrane and reduce interface peeling caused by membrane swelling or shrinkage, the first nanoscale platinum carbon layer is rolled to form a dense microporous layer on the surface of the proton exchange membrane.

[0011] Furthermore, in order to provide a larger diffusion channel for the reactant gas and reduce the resistance of the gas entering the catalyst layer from the outside, the porosity of the dense microporous layer and the first nanoscale platinum-carbon layer and the second nanoscale platinum-carbon layer after being rolled increases sequentially.

[0012] Furthermore, a gas diffusion layer is provided on the outer side of the gradient catalytic layer.

[0013] Furthermore, in order to quickly remove excess reaction water and prevent water from accumulating at the interface between the membrane and the catalyst layer, the surface hydrophobic angle of the gas diffusion layer is 130°~160°, and the internal hydrophilic angle of the dense microporous layer is 50°~20°.

[0014] A production apparatus for a gradient catalytic layer composite membrane electrode includes the gradient catalytic layer composite membrane electrode as described in any one of the above claims, and further includes a proton exchange membrane disposed on a rotating roller, a magnetron sputtering mechanism and a double-sided transfer mechanism cooperating with the proton exchange membrane, and a roller pressing mechanism, which are respectively used to sputter a first nanoscale platinum-carbon layer on the proton exchange membrane, transfer a second nanoscale platinum-carbon layer, and press the first nanoscale platinum-carbon layer and the second nanoscale platinum-carbon layer onto the proton exchange membrane.

[0015] Furthermore, in order to verify whether the membrane electrode is qualified, a resistance detection mechanism is also included, which is located downstream of the rolling mechanism to detect the resistance of the membrane electrode.

[0016] The beneficial effects of this utility model are:

[0017] 1. This utility model constructs a highly efficient gas-mass electron transport channel by setting a gradient catalyst layer on a proton exchange membrane, with the porosity increasing gradually from the inside to the outside.

[0018] 2. This invention uses magnetron sputtering to directionally deposit platinum particles on a proton exchange membrane to form a nano-platinum gradient catalyst layer, thereby increasing the power density;

[0019] 3. By setting up an intelligent rolling system, this utility model enables the nano-platinum layer to form a dense microporous layer on the proton exchange membrane, eliminating the nanoscale gap between the catalyst layer and the membrane, inhibiting reverse current corrosion, reducing interfacial peeling caused by membrane swelling or shrinkage, thus extending the membrane electrode life and improving performance after thermal cycling.

[0020] 4. The production device of this utility model, by setting up a matching magnetron sputtering mechanism, a double-sided transfer mechanism and a roller pressing mechanism, standardizes production, improves product yield and reduces the cost per piece. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the gradient catalytic layer composite membrane electrode of this utility model;

[0023] Figure 2 This is a schematic diagram of the modular membrane electrode production device of this utility model.

[0024] In the figure: 1. Gradient catalytic layer, 2. Gas diffusion layer, 3. Proton exchange membrane, 5. Magnetron sputtering mechanism, 6. Double-sided transfer mechanism, 7. Intelligent rolling mechanism, 8. Resistance detection mechanism. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] like Figure 1 As shown in Embodiment 1 of this utility model, a gradient catalytic layer composite membrane electrode and its production apparatus include a proton exchange membrane 3, with gradient catalytic layers 1 disposed on both sides of the proton exchange membrane 3. The porosity of the gradient catalytic layer 1 increases from the inside to the outside, that is, the density of the gradient catalytic layer 1 decreases from the inside to the outside, thereby constructing a highly efficient gas-mass electron transport channel.

[0027] Furthermore, the gradient catalytic layer 1 includes a first nanoscale platinum-carbon layer formed by magnetron sputtering, achieving directional deposition of platinum particles. Simultaneously, magnetron sputtering is performed on both sides of the proton exchange membrane 3 to form a double-sided first nanoscale platinum-carbon layer in a single operation. In this embodiment, the grain size is 46 nm.

[0028] Furthermore, the gradient catalyst layer 1 also includes a second nanoscale platinum-carbon layer formed by transfer printing, the second nanoscale platinum-carbon layer being located outside the first nanoscale platinum-carbon layer. A one-piece molded double-sided catalyst layer with a positional deviation ≤ ±50 μm.

[0029] Furthermore, the density of the first nanoscale platinum-carbon layer is greater than that of the second nanoscale platinum-carbon layer. Also, after being rolled, the first nanoscale platinum-carbon layer forms a dense microporous layer on the surface of the proton exchange membrane 3.

[0030] Furthermore, the porosity of the dense microporous layer and the first and second nanoscale platinum-carbon layers after rolling increases sequentially. The inner dense microporous layer, which is close to the proton exchange membrane, has low porosity and weak water retention capacity; the outer second nanoscale platinum-carbon layer has high porosity (porous structure), providing a larger water storage space and drainage channels. This allows the water generated in the reaction to migrate from the low-porosity region on the inside to the high-porosity region on the outside under the influence of the concentration gradient, avoiding accumulation at the catalyst layer and membrane interface (i.e., "flooding"). This makes the membrane electrode more suitable for high humidity, low temperature start-up, or special operating conditions.

[0031] Example 2 differs from Example 1 in that, as Figure 1 As shown, a gas diffusion layer 2, namely GDL, is also provided on the outer side of the gradient catalytic layer 1.

[0032] Furthermore, the surface hydrophobic angle of the gas diffusion layer 2 is 130°~160°, and the internal hydrophilic angle of the dense microporous layer is 50°~20°, forming a gradient wetting structure. In this embodiment, the surface hydrophobic angle of the gas diffusion layer is 145°, and the internal hydrophilic angle of the microporous layer is 35°.

[0033] Example 3: A production apparatus for a gradient catalytic layer composite membrane electrode, such as... Figure 2As shown, the composite membrane electrode comprising any of the aforementioned gradient catalytic layers further includes a proton exchange membrane 3 disposed on a rotating roller, a magnetron sputtering mechanism 5 and a double-sided transfer mechanism 6 cooperating with the proton exchange membrane 3, and a roller pressing mechanism 7, which are respectively used to sputter a first nanoscale platinum-carbon layer on the proton exchange membrane 3, transfer a second nanoscale platinum-carbon layer, and press the first and second nanoscale platinum-carbon layers onto the proton exchange membrane 3. The two ends of the proton exchange membrane 3 are disposed on the rotating roller, allowing the proton exchange membrane 3 to move slowly with the rotation of the roller. The magnetron sputtering mechanism 5 is disposed on the upper and lower sides of the proton exchange membrane 3 to sputter platinum-carbon catalyst slurry onto both sides of the proton exchange membrane 3, forming the first nanoscale platinum-carbon layer. The double-sided transfer mechanism 6 is also disposed on the upper and lower sides of the proton exchange membrane 3, and is located downstream of the magnetron sputtering mechanism 5, transferring the second nanoscale platinum-carbon layer onto the first nanoscale platinum-carbon layer. The roller pressing mechanism 7 is located downstream of the magnetron sputtering mechanism 5, and the roller pressing mechanism 7 presses the proton exchange membrane 3 with the first nanoscale platinum carbon layer and the second nanoscale platinum carbon layer. This not only makes the catalyst layer and the membrane in close contact, but also regulates the microstructure of the gradient structure, forming a dense microporous layer on the surface of the proton exchange membrane to eliminate the nanoscale gap between the catalyst layer and the membrane, suppress reverse current corrosion, and reduce interface peeling caused by membrane swelling or shrinkage, thereby extending the membrane electrode life and improving performance after thermal cycling.

[0034] Example 4 differs from Example 3 in that it also includes a resistance detection mechanism 8 located downstream of the rolling mechanism 7 for detecting the resistance of the membrane electrode and for verifying whether the membrane electrode is qualified.

[0035] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions of some or all of the technical features thereof, within the spirit and principles of the present invention, do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A gradient catalytic layer composite membrane electrode comprising a proton exchange membrane (3), characterized in that, The proton exchange membrane (3) has a gradient catalytic layer (1) with increasing porosity from the inside to the outside on both sides.

2. The gradient catalyst layer composite membrane electrode according to claim 1, wherein The gradient catalytic layer (1) includes a first nanoscale platinum carbon layer formed by magnetron sputtering.

3. The gradient catalyst layer composite membrane electrode according to claim 2, wherein The gradient catalytic layer (1) also includes a second nanoscale platinum carbon layer formed by transfer, which is located outside the first nanoscale platinum carbon layer.

4. The gradient catalytic layer composite film electrode according to claim 3, characterized in that, The density of the first nanoscale platinum carbon layer is greater than that of the second nanoscale platinum carbon layer.

5. The gradient catalytic layer composite film electrode according to claim 4, characterized in that, After the first nanoscale platinum carbon layer is rolled, a dense microporous layer is formed on the surface of the proton exchange membrane (3).

6. The gradient catalytic layer composite film electrode according to claim 5, characterized in that, The porosity of the dense microporous layer and the first and second nanoscale platinum-carbon layers after rolling increases sequentially.

7. The gradient catalytic layer composite film electrode according to claim 5 or 6, characterized in that, A gas diffusion layer (2) is also provided on the outside of the gradient catalytic layer (1).

8. The gradient catalytic layer composite film electrode according to claim 7, characterized in that, The surface hydrophobic angle of the gas diffusion layer (2) is 130°~160°, and the internal hydrophilic angle of the dense microporous layer is 50°~20°.

9. A production apparatus for a gradient catalytic layer composite membrane electrode, characterized in that, The gradient catalytic layer composite membrane electrode according to any one of claims 1 to 8 further includes a proton exchange membrane (3) disposed on a rotating roller, a magnetron sputtering mechanism (5) cooperating with the proton exchange membrane (3), a double-sided transfer mechanism (6), and a roller pressing mechanism (7), which are respectively used to sputter a first nanoscale platinum carbon layer on the proton exchange membrane (3), transfer a second nanoscale platinum carbon layer, and press the first nanoscale platinum carbon layer and the second nanoscale platinum carbon layer onto the proton exchange membrane (3).

10. The production apparatus for the gradient catalytic layer composite film electrode according to claim 9, characterized in that, It also includes a resistance detection mechanism (8) located downstream of the rolling mechanism (7) for detecting the resistance of the membrane electrode.

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