An ultrathin integrated layered composite film – electrode, membrane, preparation and application

Abstract

This invention belongs to the field of proton exchange membrane fuel cells, and specifically relates to a method for preparing an ultrathin integrated layered composite membrane-electrode and its application in hydrogen fuel cells. Using a gas diffusion electrode as the membrane support, electrostatic atomization combined with direct membrane deposition is employed to simultaneously deposit a two-dimensional nanosheet dispersion and a proton carrier molecular solution onto the electrode to form a layered composite membrane, thus obtaining the integrated electrode with the layered composite membrane. The integrated layered composite membrane-electrode prepared by this invention has an ultrathin membrane thickness and exhibits superior vertical proton conduction capability and hydrogen fuel cell performance compared to self-supporting layered membranes.

Description

Technical Field

[0001] This invention belongs to the field of proton exchange membrane fuel cells, and specifically relates to a method for preparing an ultrathin integrated layered composite membrane-electrode and its application in hydrogen fuel cells. Background Technology

[0002] With the rapid development of the global economy and technology, energy issues are becoming increasingly severe. The traditional energy system, dominated by oil, coal, and natural gas, is not only non-renewable but also causes serious environmental pollution. Therefore, developing clean new energy sources is crucial for adjusting the energy structure and achieving sustainable development. Fuel cells, due to their high energy density, low pollution, wide applicability, and low noise, are considered the most promising high-efficiency power generation technology of the 21st century. Among them, proton exchange membrane fuel cells (PEMFCs) have high energy conversion efficiency, large operating current, zero pollution, and simple structure, and are currently widely used. The proton exchange membrane (PEM) is a key component of PEMFCs; its proton conductivity and stability determine the battery's performance and lifespan. Currently, developed PEMs are mainly polymer membranes, such as commercial Nafion-type perfluorosulfonic acid membranes. However, these membranes are expensive, thick (~100 μm), and have complex and unstable proton transport channel structures. Under high temperature and low humidity conditions, the ion channels inside the membrane shrink or even collapse due to water loss, leading to a severe decrease in proton conductivity. These problems limit the further development and application of high-performance PEMFC technology. In recent years, the rapid development of two-dimensional materials has attracted attention and research to layered membranes. In particular, two-dimensional layered membranes, due to their advantages such as ultrathin, defect-free membrane structure, long-range regular interlayer channels, and strong tunability and designability, have gradually become a new platform for the development of high-performance PEMs (platelets for hydrogen fuel cells). However, most nanosheet-assembled layered membranes currently lack sufficient proton carrier groups, resulting in generally low proton conductivity. Moreover, because layered membranes are stacked nanosheets, the proton transmembrane transport path is long and tortuous, and the vertical conductivity is typically 1-3 orders of magnitude lower than the horizontal conductivity. Therefore, it is crucial to regulate and optimize the chemical environment and physical structure of layered membranes to develop a layered thin film with high vertical proton conductivity and hydrogen fuel cell performance. Summary of the Invention

[0003] The purpose of this invention is to provide an ultrathin integrated layered composite membrane-electrode, wherein the membrane on the electrode has an ultrathin thickness and exhibits higher vertical proton conduction capacity and hydrogen fuel cell performance compared to self-supporting layered membranes.

[0004] The technical solution adopted in this invention is as follows:

[0005] A method for preparing an ultrathin integrated layered composite film-electrode involves using a gas diffusion electrode as the support for the film, and employing electrostatic atomization combined with direct film deposition to simultaneously deposit a two-dimensional nanosheet dispersion and a proton carrier molecular solution for film formation onto the electrode to form a layered composite film, thereby obtaining the integrated electrode with the layered composite film.

[0006] Specifically, a two-dimensional nanosheet dispersion and a proton carrier molecular solution for film formation can be prepared first; then, using a dual-needle electrostatic atomization technique combined with direct membrane deposition, two-dimensional nanosheets and a proton carrier molecular solution can be directly and simultaneously atomized and deposited on the gas diffusion electrode of a fuel cell to form an ultrathin layered composite membrane, thus obtaining an integrated layered composite membrane-electrode.

[0007] The thickness of the layered composite film prepared on the electrode is 60-550 nm, more preferably 300-400 nm.

[0008] The two-dimensional nanosheets preferably have a lateral dimension of 1-2 μm and a thickness of 1.3-1.6 nm. Specifically, vermiculite (Vr) nanosheets, graphene oxide nanosheets, etc., can be selected, but are not limited to.

[0009] The preferred mass ratio of the two-dimensional nanosheets in the two-dimensional nanosheet dispersion to the proton carrier molecules in the proton carrier molecule solution is 3-5:1, more preferably 4:1.

[0010] Specifically, the preferred concentration of the dispersion of the two-dimensional nanosheets is 0.1 mg / mL, and the dispersant is a mixed solution of ethanol and water in a volume ratio of 4:3.

[0011] The concentration of the proton carrier molecule solution is preferably 0.025 mg / mL, and the dispersant is a mixture of ethanol and water or N,N-dimethylformamide in a volume ratio of 4:3. The proton carrier molecule can be selected from, but is not limited to, functional carbon dots (S@N-CD), Nafion, sulfonated polyether ether ketone, chitosan, and other carrier molecules.

[0012] In the dual-needle electrostatic atomization device, the two syringes contain a two-dimensional nanosheet dispersion and a proton carrier molecule solution, respectively.

[0013] Furthermore, the amount of the two-dimensional nanosheets and the proton carrier molecular solution used for atomization is 10-90 mL each, preferably 60-90 mL, and particularly preferably 60 mL.

[0014] Furthermore, the temperature of the electrostatic atomizing device is set to 40–50°C, the forward speed of the peristaltic pump is 0.003–0.006 mm / s, preferably 0.005 mm / s; the reciprocating speed of the syringe along the X-axis is 2–5 mm / s, preferably 3 mm / s; the distance between the two needles and the receiving substrate is 8–12 cm, preferably 10 cm; the needles are connected to a 15–20 kV high-voltage power supply, preferably 16 kV; and the roller speed is 90 r / min.

[0015] The aforementioned ultrathin integrated layered composite membrane-electrode has excellent applications in hydrogen fuel cells.

[0016] This invention utilizes a dual-needle electrostatic atomization technique combined with direct membrane deposition to simultaneously deposit a nanosheet dispersion and a proton carrier molecular solution directly onto a gas diffusion electrode, forming an ultrathin layered composite membrane and simultaneously fabricating an integrated layered composite membrane-electrode. The ultrathin membrane thickness (<600 nm) significantly shortens the proton transmembrane transport path. Simultaneously, the dual-needle electrostatic atomization technique allows for the stacking of nanosheets and carrier molecules, with molecules carrying abundant functional groups acting as "bridges" for proton translayer transport, accelerating proton transfer. Therefore, the layered composite membrane exhibits excellent vertical proton conductivity and hydrogen fuel cell performance. For example, at 90℃ and 100% RH, the composite membrane achieves a vertical proton conductivity of 132.5 mS / cm; at 75℃ and 100% RH, the hydrogen fuel cell assembled with the integrated composite membrane-electrode achieves a maximum power density and current density of 394.1 mW / cm², respectively. 2 and 1302.2 mA / cm 2 Compared to current self-supporting layered membranes, this invention uses a gas diffusion electrode as the membrane support, which greatly reduces the thickness of the layered membrane and decreases the resistance to proton transmembrane transport. Therefore, it significantly improves the vertical proton conduction capability of the layered membrane, making it a promising candidate for application in hydrogen fuel cells.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] The integrated layered composite membrane-electrode prepared by this invention has an ultra-thin membrane thickness and exhibits superior vertical proton conduction capability and hydrogen fuel cell performance compared with self-supporting layered membranes. Attached Figure Description

[0019] Figure 1 Atomic force microscopy (AFM) images of the Vr nanosheets prepared in Example 1;

[0020] Figure 2Images of the S@N-CD solution prepared in Example 1 under fluorescent light and 365nm ultraviolet light. Left: Image under fluorescent light; Right: Image under 365nm ultraviolet light.

[0021] Figure 3 Transmission electron microscope (TEM) image of the S@N-CD prepared in Example 1;

[0022] Figure 4 Surface scanning electron microscope (SEM) image of Vr / S@N-CD-60 prepared for Example 1;

[0023] Figure 5 The cross-sectional SEM image of Vr / S@N-CD-60 prepared in Example 1;

[0024] Figure 6 SEM image of the surface of Vr / Nafion-60 prepared in Example 2;

[0025] Figure 7 Cross-sectional SEM images of Vr / Nafion-60 prepared in Example 2;

[0026] Figure 8 Cross-sectional SEM images of Vr-60 prepared for Comparative Example 1;

[0027] Figure 9 Cross-sectional SEM images of Vr / S@N-CD-10 prepared for Comparative Example 2;

[0028] Figure 10 Cross-sectional SEM images of Vr / S@N-CD-30 prepared for Comparative Example 3;

[0029] Figure 11 Cross-sectional SEM images of Vr / S@N-CD-90 prepared for Comparative Example 4;

[0030] Figure 12 Temperature-conductivity diagrams of Vr / S@N-CD-60, Vr / Nafion-60, Vr-60, and Vr / S@N-CD-90 prepared in Examples 1 and 2 and Comparative Examples 1 and 4;

[0031] Figure 13 The output performance graphs of hydrogen fuel cells Vr / S@N-CD-60, Vr / Nafion-60, Vr-60 and Vr / S@N-CD-90 prepared in Examples 1 and 2 and Comparative Examples 1 and 4 are shown. Detailed Implementation

[0032] The technical solution of the present invention is illustrated below with specific embodiments, but the scope of protection of the present invention is not limited thereto:

[0033] Example 1

[0034] The preparation of an ultrathin integrated layered composite film-electrode includes the following steps:

[0035] 1) Preparation of vermiculite (Vr) nanosheets (other existing methods can also be used): 2g of thermally expanded Vr was added to a saturated sodium chloride solution, and the mixture was magnetically stirred at 120℃ for 48h. Then, it was washed 5 times with deionized water (hereinafter referred to as water) and dried for 48h to obtain sodium ion intercalated Vr, denoted as Vr-Na. + Then, Vr-Na + The mixture was added to a 2 mol / L lithium chloride solution, magnetically stirred at 120 °C for 24 h, washed five times with water, and dried for 48 h to obtain lithium-ion intercalated Vr, denoted as Vr-Li. + Then, Vr-Li + Dispersed in 1 mmol / L hydrochloric acid solution and stirred for 12 h to replace lithium ions with hydrogen ions, then washed five times with water and dried for 48 h, the resulting product is denoted as Vr-H. + Take 0.5g of Vr-H + Add to 200 mL of water, stir magnetically for 30 min, sonicate for 60 min, then centrifuge the mixture (8000 r / min, 20 min) to remove unpeeled Vr, and take the supernatant to obtain Vr nanosheet dispersion. The concentration of the Vr nanosheet dispersion was measured to be approximately 1 mg / mL by drying and weighing.

[0036] 2) Preparation of functional carbon dots (S@N-CD): 0.5 g of aminosulfonic acid and 0.25 mL of ethylenediamine were dissolved in 10 mL of water and stirred for 2 h; then the dispersion was microwaved at 750 W for 2 min and allowed to cool naturally to room temperature; subsequently, the resulting dark brown solid was dispersed in 10 mL of water and centrifuged at 10000 r for 10 min; then the supernatant was filtered through a 0.10 μm filter membrane and freeze-dried for 48 h to obtain S@N-CD powder.

[0037] 3) Fabrication of integrated layered composite film-electrode:

[0038] a) Vr nanosheets and S@N-CD powder were uniformly dispersed in a mixed solution of ethanol and water (4:3, v / v) to prepare a 0.1 mg / mL Vr nanosheet atomization solution and a 0.025 mg / mL S@N-CD atomization solution.

[0039] b) Take 60 mL of each of the two solutions from step a) above and add them to two syringes. Use a dual-needle electrostatic atomization device to atomize and deposit the two substances simultaneously, so that Vr nanosheets and S@N-CD are uniformly deposited on the gas diffusion electrode to form a layered composite film. At the same time, an integrated composite film-electrode is obtained. This layered composite film is denoted as Vr / S@N-CD-60.

[0040] During the electrostatic atomization process, the instrument temperature was set to 40℃, the peristaltic pump was pushed forward at a speed of 0.005mm / s, the syringe reciprocated along the X-axis at a speed of 3mm / s, the distance between the two needles and the receiving substrate was 10cm, the needles were connected to a 16kV high-voltage power supply, and the roller speed was maintained at 90r / min.

[0041] Example 2

[0042] A method for preparing an ultrathin integrated layered composite film-electrode includes the following steps:

[0043] 1) The preparation of Vr nanosheets is the same as in Example 1.

[0044] 2) Preparation of Nafion solution: The solvent of commercial Nafion membrane solution (5 wt%) was removed by heating in a vacuum drying oven at 60 °C to obtain dried Nafion solid. Then, the Nafion solid was dissolved in a mixed solution of ethanol and N,N-dimethylformamide (4:3, v / v) to a concentration of 0.025 mg / mL.

[0045] 3) Fabrication of integrated layered composite film-electrode:

[0046] a) Disperse Vr nanosheets in a mixed solution of ethanol and water (4:3, v / v) to prepare a 0.1 mg / mL Vr nanosheet atomization solution;

[0047] b) Take 60 mL of the Nafion solution from step 2) and the Vr nanosheet solution from step a) and add them to two syringes respectively. Use a dual-needle electrostatic atomization device to atomize and deposit the two substances simultaneously, so that the Vr nanosheets and Nafion are uniformly deposited on the gas diffusion electrode to form a layered composite film. At the same time, an integrated composite film-electrode is obtained. This layered composite film is denoted as Vr / Nafion-60.

[0048] During the electrostatic atomization process, the instrument temperature was set to 40℃, the peristaltic pump was pushed forward at a speed of 0.005mm / s, the syringe reciprocated along the X-axis at a speed of 3mm / s, the distance between the two needles and the receiving substrate was 10cm, the needles were connected to a 16kV high-voltage power supply, and the roller speed was maintained at 90r / min.

[0049] Comparative Example 1

[0050] The fabrication of an ultrathin integrated VR layered film electrode includes the following steps:

[0051] 1) The preparation of Vr nanosheets is the same as in Example 1.

[0052] 2) Fabrication of integrated VR layered film-electrode:

[0053] a) Disperse Vr nanosheets in a mixed solution of ethanol and water (4:3, v / v) to prepare a 0.1 mg / mL Vr nanosheet atomization solution;

[0054] b) Take 60 mL of the Vr nanosheet dispersion from step a) above and add it to two syringes. Use a dual-needle electrostatic atomization device to atomize and deposit the Vr nanosheets to form a pure Vr layered film. At the same time, an integrated membrane-electrode is obtained. This layered film is denoted as Vr-60.

[0055] The electrostatic atomization deposition process parameters are the same as in Example 1.

[0056] Comparative Example 2

[0057] The preparation of an ultrathin integrated layered composite film-electrode includes the following steps:

[0058] 1) The preparation of Vr nanosheets is the same as in Example 1.

[0059] 2) The preparation of S@N-CD is the same as in Example 1.

[0060] 3) Fabrication of integrated layered composite film-electrode:

[0061] a) The preparation and concentration of Vr nanosheets and S@N-CD atomization solution are the same as in Example 1;

[0062] b) Take 10 mL of each of the two solutions from step a) above and add them to two syringes. Use a dual-needle electrostatic atomization device to atomize and deposit the two substances simultaneously, so that Vr nanosheets and S@N-CD are uniformly deposited on the gas diffusion electrode to form a layered composite film. At the same time, an integrated composite film-electrode is obtained. This layered composite film is denoted as Vr / S@N-CD-10.

[0063] The electrostatic atomization deposition process parameters are the same as in Example 1.

[0064] Comparative Example 3

[0065] The preparation of an ultrathin integrated layered composite film-electrode includes the following steps:

[0066] 1) The preparation of Vr nanosheets is the same as in Example 1.

[0067] 2) The preparation of S@N-CD is the same as in Example 1.

[0068] 3) Fabrication of integrated layered composite film-electrode:

[0069] a) The preparation and concentration of Vr nanosheets and S@N-CD atomization solution are the same as in Example 1;

[0070] b) Take 30 mL of each of the two solutions from step a) above and add them to two syringes. Use a dual-needle electrostatic atomization device to atomize and deposit the two substances simultaneously, so that Vr nanosheets and S@N-CD are uniformly deposited on the gas diffusion electrode to form a layered composite film. At the same time, an integrated composite film-electrode is obtained. This layered composite film is denoted as Vr / S@N-CD-30.

[0071] The electrostatic atomization deposition process parameters are the same as in Example 1.

[0072] Comparative Example 4

[0073] The preparation of an ultrathin integrated layered composite film-electrode includes the following steps:

[0074] 1) The preparation of Vr nanosheets is the same as in Example 1.

[0075] 2) The preparation of S@N-CD is the same as in Example 1.

[0076] 3) Fabrication of integrated layered composite film-electrode:

[0077] a) The preparation and concentration of Vr nanosheets and S@N-CD atomization solution are the same as in Example 1;

[0078] b) Take 90 mL of each of the two solutions from step a) above and add them to two syringes. Use a dual-needle electrostatic atomization device to atomize and deposit the two substances simultaneously, so that Vr nanosheets and S@N-CD are uniformly deposited on the gas diffusion electrode to form a layered composite film. At the same time, an integrated composite film-electrode is obtained. This layered composite film is denoted as Vr / S@N-CD-90.

[0079] The electrostatic atomization deposition process parameters are the same as in Example 1.

[0080] Effect Experiment:

[0081] To illustrate the effects of the present invention, the nanomaterials and thin films prepared in the examples and comparative examples were characterized and tested, and the proton conductivity and hydrogen fuel cell performance of the obtained integrated membrane-electrode were tested.

[0082] Specific testing methods and results:

[0083] 1. AFM test:

[0084] The size and thickness of the prepared VR nanosheets were characterized by AFM (Analogous Fluid Dynamics). Specifically, a diluted VR nanosheet dispersion was dropped onto a silicon wafer, dried, and then characterized. This invention used a Bruker Dimension FastScan™ AFM testing instrument in FastScan mode. The test results are shown below. Figure 1 As shown.

[0085] AFM test results show that the Vr nanosheets are 1-2 μm in size and 1.3-1.6 nm in thickness.

[0086] 2. Fluorescence effect test:

[0087] The prepared S@N-CD powder was formulated into an aqueous solution of a certain concentration, and its fluorescence effect was tested under sunlight and under a 365nm ultraviolet lamp, respectively. The results are shown in the figure. Figure 2 As shown.

[0088] Fluorescence effect test results show that the S@N-CD aqueous solution is pale yellow and transparent under sunlight. Figure 2 (Left), exhibits fluorescence under 365nm ultraviolet light ( Figure 2 (Right) illustrates the successful preparation of S@N-CD.

[0089] 3. TEM test:

[0090] The diluted S@N-CD dispersion was dropped onto a copper grid, dried, and then subjected to TEM testing. This invention uses a FEITecnai G2 F20 TEM testing instrument; the results are shown below. Figure 3 As shown.

[0091] TEM test results show that the prepared S@N-CD has a spherical structure with a size of about 4 nm, and the magnified TEM image shows that it has lattice stripes.

[0092] 4. SEM testing:

[0093] The obtained integrated film electrode was cut to a certain size, parallelly attached to the sample stage, sputtered with gold, and then subjected to surface SEM testing. The integrated film electrode was quenched in a liquid nitrogen atmosphere, vertically attached to the sample stage, sputtered with gold, and then subjected to cross-sectional SEM testing. This invention uses a JSM-6700F (JEOL) or TESCAN Mira SEM instrument, and an Eiko IB-3IONCOATER ion sputtering system for gold sputtering. The test results are shown below. Figures 4-11 As shown.

[0094] Surface SEM results show that the Vr / S@N-CD-60 and Vr / Nafion-60 films prepared in the examples have smooth, defect-free surfaces and completely cover the catalyst layer. Cross-sectional SEM results show that the thickness of the Vr / S@N-CD-60 layered composite film is approximately 360 nm, the thickness of the Vr / Nafion-60 layered composite film is approximately 350 nm, the thickness of the Vr-60 layered film prepared in the comparative example is approximately 320 nm, the thickness of the Vr / S@N-CD-10 layered composite film is approximately 60 nm, the thickness of the Vr / S@N-CD-30 layered composite film is approximately 170 nm, and the thickness of the Vr / S@N-CD-90 layered composite film is approximately 550 nm.

[0095] Compared to the Vr-60 layered membrane, the thickness of the layered composite membrane (Vr / S@N-CD-60 or Vr / Nafion-60) is increased after intercalation with proton carrier molecules (S@N-CD or Nafion). Moreover, the thickness of the layered composite membrane can be controlled by the amount of atomizing solution used.

[0096] 5. Proton conductivity test:

[0097] Proton conductivity was evaluated using AC impedance spectroscopy, conducted on a ParStat MC 1000 electrochemical workstation. The scanning frequency range was 1 MHz–10 Hz, the oscillation voltage was 20 mV, and the temperature and humidity were controlled using a constant temperature and humidity chamber. The test involved placing two integrated membrane electrodes face-to-face and stabilizing them at specific temperature and humidity for 1 hour before testing. Proton conductivity was calculated using the following formula:

[0098]

[0099] Where l (cm) is the distance between the two electrodes, and A (cm) is the distance between the two electrodes. 2 R(Ω) is the cross-sectional area along the current direction, and R(Ω) is the impedance being tested.

[0100] The results of the proton conductivity test are shown below. Figure 12As shown, the results indicate that under a relative humidity of 100%, the conductivity of the Vr / S@N-CD-60 membrane at temperatures of 30, 45, 60, 75, and 90℃ is 32.3, 52.2, 75.0, 97.5, and 132.5 mS / cm, respectively; the conductivity of the Vr / Nafion-60 membrane at the same temperatures is 27.1, 44.9, 67.8, 86.2, and 113.2 mS / cm, respectively; and the conductivity of the comparative Vr-60 membrane at temperatures of 30, 45, 60, 75, and 90℃ is 132.5 mS / cm, respectively. The conductivity at 0, 75, and 90℃ is 3.6, 7.1, 10.8, 15.3, and 19.6 mS / cm, respectively; the conductivity of Vr / S@N-CD-90 film at 30, 45, 60, 75, and 90℃ is 19.6, 30.0, 50.5, 69.2, and 86.9 mS / cm, respectively; however, the Vr / S@N-CD-10 and Vr / S@N-CD-30 films are too thin, making them prone to short circuits during impedance testing at elevated temperatures, thus failing to obtain accurate conductivity performance.

[0101] The data above show that, compared to the prepared pure Vr-60 layered membrane, the proton conductivity of the Vr / S@N-CD-60 and Vr / Nafion-60 layered composite membranes was significantly improved. This is mainly due to the insertion of proton carrier molecules between the membrane layers, increasing the concentration of proton carriers within the membrane and thus constructing a continuous proton transport channel. Compared to the Vr / Nafion-60 composite membrane, the Vr / S@N-CD-60 composite membrane has higher proton conductivity, primarily attributed to the inherent and ordered acid-base groups and higher group density of the S@N-CD carbon dots. Furthermore, the proton conductivity of the comparative Vr / S@N-CD-90 composite membrane is lower than that of the Vr / S@N-CD-60 composite membrane, mainly because the path for proton transport in the vertical direction across the membrane becomes longer with increasing membrane thickness.

[0102] 6. Hydrogen fuel cell performance testing

[0103] A catalyst slurry was prepared by mixing 40% Pt / C catalyst powder with isopropanol, Nafion membrane solution, and deionized water in a certain proportion, wherein Nafion accounted for 20 wt% of the catalyst. Then, the catalyst slurry was uniformly coated onto a gas diffusion layer using an ultrasonic sprayer at a temperature of 40°C. The catalyst-loaded gas diffusion layer was then dried in a drying oven for 4 hours to allow solvent evaporation, thus obtaining the gas diffusion electrode. The catalyst loading at both the cathode and anode was 0.5 mg / cm³. 2Two integrated membrane electrode assemblies (MEAs) are placed face-to-face and pressed together to form a single cell. Sealing gaskets, graphite plates, and other components are then assembled on both sides of the MEA. Single-cell performance was tested using an Arbin FCTS-50H fuel cell testing system. H2 and O2 were introduced at flow rates of 90 sccm and 120 sccm respectively at the anode and cathode. The operating temperature was set to 75°C, and the relative humidity to 100%.

[0104] The single-cell performance test results of the integrated membrane-electrode are shown in [link to data]. Figure 13 As shown, the results indicate that the maximum power density of the single cell assembled with Vr / S@N-CD-60 film-electrode is 394.1 mW / cm² under the conditions of 75℃ and 100% relative humidity. 2 The maximum current density is 1302.2 mA / cm². 2 The maximum power density of a single cell assembled with Vr / Nafion-60 membrane-electrode is 310.2 mW / cm². 2 The maximum current density is 1014.3 mA / cm². 2 The maximum power density of the single cell assembled with the comparative Vr-60 membrane-electrode system was 98.4 mW / cm². 2 The maximum current density is 339.1 mA / cm². 2 The maximum power density of a single cell assembled with Vr / S@N-CD-90 film-electrode system is 252.7 mW / cm². 2 The maximum current density is 890.4 mA / cm². 2 .

[0105] The hydrogen fuel performance test data shows that the prepared Vr / S@N-CD-60 and Vr / Nafion-60 composite membrane electrodes have higher battery output performance compared to Vr-60 membrane electrodes. This is mainly due to their higher proton conductivity, which accelerates the conversion between chemistry and energy.

[0106] In summary, this invention uses dual-needle electrostatic atomization technology combined with direct membrane deposition to prepare an integrated layered composite membrane-electrode with ultra-thin film thickness. This layered composite membrane has excellent vertical proton conductivity, and the single cell assembled with the integrated composite membrane-electrode also exhibits excellent hydrogen fuel cell performance.

Claims

1. A method for preparing an ultrathin integrated layered composite film-electrode, characterized in that, Using a gas diffusion electrode as the membrane support, a layered composite membrane is formed by simultaneously depositing a two-dimensional nanosheet dispersion and a proton carrier molecular solution onto the electrode using a dual-needle electrostatic atomization combined with direct membrane deposition, thereby obtaining an integrated electrode with a layered composite membrane. The thickness of the prepared layered composite membrane is 60-550 nm. In the dual-needle electrostatic atomization device, the two syringes contain a two-dimensional nanosheet dispersion and a proton carrier molecular solution, respectively. The proton carrier molecules are selected from functional carbon dots, sulfonated polyether ether ketone, and chitosan.

2. The method for preparing the ultrathin integrated layered composite film-electrode as described in claim 1, characterized in that, The mass ratio of two-dimensional nanosheets in the two-dimensional nanosheet dispersion to proton carrier molecules in the proton carrier molecule solution is 3-5:

1.

3. The method for preparing the ultrathin integrated layered composite film-electrode as described in claim 1, characterized in that, The two-dimensional nanosheets have a lateral dimension of 1-2 μm and a thickness of 1.3-1.6 nm.

4. The method for preparing the ultrathin integrated layered composite film-electrode as described in claim 2, characterized in that, The concentration of the dispersion of the two-dimensional nanosheets was 0.1 mg / mL, and the dispersant was a mixed solution of ethanol and water in a volume ratio of 4:3; the concentration of the proton carrier molecule solution was 0.025 mg / mL, and the dispersant was a mixed solution of ethanol and water or N,N-dimethylformamide in a volume ratio of 4:

3.

5. The method for preparing the ultrathin integrated layered composite film-electrode as described in claim 2, characterized in that, The volumes of the two-dimensional nanosheet dispersion and the proton carrier molecular solution used for atomization deposition are each 10 to 90 mL.

6. The method for preparing an ultrathin integrated layered composite film-electrode as described in any one of claims 1-5, characterized in that, The temperature of the electrostatic atomizing device is set to 40 ~ 50℃, the forward speed of the peristaltic pump is 0.003 ~ 0.006 mm / s, the speed of the syringe reciprocating along the X-axis is 2 ~ 5 mm / s, the distance between the two needles and the receiving substrate is 8 ~ 12 cm, the needles are connected to a 15 ~ 20 kV high-voltage power supply, and the roller speed is 90 r / min.

7. The ultrathin integrated layered composite film-electrode obtained by any of the preparation methods of claims 1-6.

8. The ultrathin integrated layered composite film of claim 7 - the layered composite film on the electrode.

9. The application of the ultrathin integrated layered composite membrane-electrode as described in claim 8 in a hydrogen fuel cell.

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