Proton conductor with molecular cage structure, preparation method and application of proton conductor in high-temperature proton exchange membrane

Abstract

The invention discloses a proton conductor with a molecular cage structure, a preparation method and application of the proton conductor in a high-temperature proton exchange membrane, the structural formula of the proton conductor with the molecular cage structure is # imgabs0 #, and X is equal to H2PO4. The invention provides a brand new organic cage proton conductor, cage molecules of the organic cage proton conductor contain a large amount of proton carrier H2PO4 <->, and amido of the organic cage proton conductor can form a wide hydrogen bond network with water molecules, so that abundant channels are provided for proton transmission, the proton conductivity of the organic cage proton conductor is remarkably improved, and the activation energy is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery materials, and particularly relates to a proton conductor with a molecular cage structure, a preparation method thereof, and an application thereof in a high-temperature proton exchange membrane. Background Art

[0002] Microbial fuel cell (MFC) is a technology that uses microorganisms to catalyze the degradation of organic matter and simultaneously generate electricity, and has broad application prospects in the field of sewage treatment. The proton exchange membrane is a key material for MFC. Among them, the perfluorosulfonic acid membrane (Nafion membrane) developed by Dupont Company in the United States has excellent chemical stability and high proton conductivity. However, the operating temperature of this membrane is generally 60-80°C, and there are disadvantages such as low proton conductivity at medium and high temperatures, excessive dependence on the water content in the membrane, and great difficulties in the preparation and sulfonation of perfluoropolymers, complex film-forming processes, and high prices. In contrast, high-temperature proton exchange membranes have various advantages: high operating temperature (100-200°C), high catalytic reaction efficiency, easy discharge of gaseous water, not prone to flooding, fast heat dissipation, and low cost. Currently, the widely used high-temperature proton exchange membranes on the market mainly include organic polymer doped membranes, metal-organic framework materials (MOF), porous covalent organic frameworks (COF), and crystalline porous organic molecules.

[0003] There are many types of organic polymer doped membranes, and the more widely studied ones include perfluorosulfonic acid (PFSA) doped membranes, polybenzimidazole (PBI) doped membranes, polyaryletherketone (PAEK), and polyarylpiperidine (PAPs), etc. Among them, although the problem that perfluorosulfonic acid doped membranes can only work in a low-temperature environment has been improved, the complex preparation process and high production cost of fluoropolymers are still difficult to solve; PBI-based membrane materials have problems such as the Trade-off effect between proton conductivity and mechanical properties, harsh synthesis conditions, poor polymer solubility, and the need to use highly toxic monomers. At the same time, the insufficient chemical stability of non-perfluorinated polymers themselves is also a problem that cannot be ignored.

[0004] Although metal-organic framework materials (MOF) have high proton conductivity, their crystals are brittle, easy to break, and have low processability, which hinders their practical application in proton exchange membranes.

[0005] The nanopores of COF proton exchange membrane materials have directionality, but in most existing film-forming processes, the arrangement direction of the pores changes randomly, changing the ordered arrangement of the pores, affecting the transport of protons. At the same time, the mechanical properties of COF membranes are relatively poor, and the membranes face problems such as fuel penetration and gas crossover during long-term use.

[0006] Crystalline porous organic molecules are emerging proton exchange membrane materials that form proton transport channels through non-covalent assembly. Among them, organic cage molecules have inherent nano-cavities, rich three-dimensional structures, and solvent processability, which enable them to form crystal materials from solvents and provide stable proton conduction paths, improving proton transport efficiency. Therefore, organic cage molecules are excellent materials for preparing solid-state proton conductors. In addition, compared with the above-mentioned organic polymers, crystalline porous organic molecules have simple synthesis steps, and their crystal structures with clear and orderly arrangements can clarify the proton transport mechanism, thus facilitating the improvement and optimization of proton conduction materials.

[0007] The reported crystalline materials of organic cage molecule proton conductors can exhibit relatively high proton conductivity at 30 °C, with the maximum proton conductivity reaching 1.3×10 -3 S / cm. However, for high-temperature proton exchange membrane materials, their operating temperature range is still relatively low, and the proton conductivity also needs to be improved. Summary of the Invention

[0008] The purpose of this section is to outline some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of the present application, to avoid obscuring the purpose of this section, the abstract, and the title, but such simplifications or omissions shall not be used to limit the scope of the present invention.

[0009] In view of the above and / or problems existing in the prior art, the present invention is proposed.

[0010] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a proton conductor with a molecular cage structure.

[0011] To solve the above technical problems, the present invention provides the following technical solution: A proton conductor with a molecular cage structure, characterized in that the structural formula of the proton conductor with a molecular cage structure is:

[0012]

[0013] wherein, X = H2PO4.

[0014] Another purpose of the present invention is to overcome the deficiencies in the prior art and provide a preparation method for a proton conductor with a molecular cage structure, including,

[0015] Dissolve reactant 1, phthalaldehyde, in concentrated sulfuric acid and heat to 60 °C, and add N-bromosuccinimide thereto in batches and react at 60 °C;

[0016] After the reaction is completed, pour the reaction solution into ice water, white solid precipitates, filter, wash the filter cake with water and hexane, and dry to obtain product 2;

[0017] The structural formula of Product 2 is:

[0018]

[0019] Dissolve Product 2, 4-cyanophenylboronic acid, and potassium carbonate in a mixed solution of tetrahydrofuran and water. Under nitrogen protection, add the catalyst tetrakis(triphenylphosphine)palladium, stir, and react at 80 °C for 10 hours;

[0020] After the reaction is completed, cool to room temperature and remove the organic solvent by rotary evaporation; add dichloromethane and water to the solid residue in sequence, shake well and let stand, remove the aqueous phase, and then wash the organic phase with water twice; after washing, dry the organic phase with anhydrous sodium sulfate, filter, and distill off the organic solvent to obtain the crude product; purify the obtained crude product by column chromatography to obtain the light yellow solid Product 3;

[0021] The structural formula of Product 3 is:

[0022]

[0023] Add Product 3 and tris(2-aminoethyl)amine to an acetonitrile solution and react at room temperature for 24 h;

[0024] After the reaction is completed, a light yellow solid precipitates in the solution. Filter, wash the filter cake with acetonitrile, and dry it under vacuum to obtain a light yellow solid;

[0025] Subsequently, dissolve the solid in a mixed solution of dichloromethane and methanol, and add sodium borohydride under an ice bath;

[0026] After reacting at room temperature for 6 hours, quench the reaction by adding water, extract the product therein with dichloromethane, and then wash it twice with an aqueous sodium carbonate solution; after washing, dry the organic phase with anhydrous sodium sulfate, filter, and distill off the organic solvent to obtain Product Cage1;

[0027] The structural formula of Product Cage1 is:

[0028]

[0029] Add an excess of phosphoric acid to Product Cage1 to adjust the pH to 0. After removing water by distillation, a solid precipitates. Filter and dry to obtain a white solid, which is the proton conductor with a molecular cage structure.

[0030] As a preferred embodiment of the preparation method described in the present invention, wherein: the ratio of isophthalaldehyde to N-bromosuccinimide is 14.9 mmol: 17.9 mmol.

[0031] As a preferred embodiment of the preparation method of the present invention, wherein: the ratio of the product, 4-cyanobenzeneboronic acid, and potassium carbonate is 10 mmol: 15 mmol: 40 mmol.

[0032] As a preferred embodiment of the preparation method of the present invention, wherein: the ratio of the catalyst tetrakis(triphenylphosphine)palladium to the product is 0.578 g: 2.13 g.

[0033] As a preferred embodiment of the preparation method of the present invention, wherein: the ratio of the product, tris(2-aminoethyl)amine, and sodium borohydride is 8 mmol: 5.4 mmol: 10 mmol.

[0034] Another object of the present invention is to overcome the deficiencies in the prior art and provide an application of a proton conductor with a molecular cage structure in the preparation of a high-temperature proton exchange membrane, including heating a commercial Nafion solution to obtain dry Nafion resin;

[0035] Redissolving the Nafion resin in DMF, adding a proton conductor with a molecular cage structure, ultrasonically dispersing, and stirring at room temperature until uniform;

[0036] Spreading the mixture evenly on a glass plate, heating, carefully peeling it off the glass plate after the composite membrane is formed, and soaking it in deionized water for storage to obtain the composite membrane.

[0037] As a preferred embodiment of the preparation method of the present invention, wherein: the mass percentage of the proton conductor with a molecular cage structure relative to Nafion is 5% - 10%.

[0038] Advantages of the present invention:

[0039] (1) The present invention proposes a novel organic cage proton conductor, whose cage-shaped molecule contains a large number of proton carriers H2PO4 - , and at the same time its amino group can form an extensive hydrogen bond network with water molecules, providing rich channels for proton transport, significantly improving its proton conductivity, and reducing the activation energy;

[0040] (2) The novel organic cage proton membrane material of the present invention has high thermal stability, does not degrade or change at a working temperature of 333 K; it can still maintain a high proton conductivity in a high-temperature and high-humidity environment;

[0041] (3) The synthesis method of the organic cage proton conductor of the present invention is simple and has a high yield. Description of the Drawings

[0042] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. Among them:

[0043] Figure 1 It is the synthesis route diagram of the proton conductor Cage2 with a molecular cage structure in the embodiments of the present invention.

[0044] Figure 2 For Cage1 in the embodiments of the present invention 1 1H NMR spectrum.

[0045] Figure 3 For Cage1 in the embodiments of the present invention 13 13C NMR spectrum.

[0046] Figure 4 For Cage2 in the embodiments of the present invention 1 1H NMR spectrum.

[0047] Figure 5 For Cage2 in the embodiments of the present invention 13 13C NMR spectrum.

[0048] Figure 6 It is the high-resolution mass spectrum (ESI) of Cage1 in the embodiments of the present invention.

[0049] Figure 7 It is the high-resolution mass spectrum (ESI) of Cage2 in the embodiments of the present invention.

[0050] Figure 8 It is the AC impedance diagram of Cage2 / Nafion-5 at different temperatures (293 - 333K) in the embodiments of the present invention (relative humidity RH = 95%).

[0051] Figure 9 It is the AC impedance diagram of Cage2 / Nafion-10 at different temperatures (293 - 333K) in the embodiments of the present invention (relative humidity RH = 95%).

[0052] Figure 10 It is the Arrhenius curve diagram of the proton conductivity of Cage2 / Nafion-5 and Cage2 / Nafion-10 versus temperature in the embodiments of the present invention (relative humidity RH = 95%).

[0053] Figure 11 It is the AC impedance diagram of Cage2 / Nafion-5 at different humidities (67 - 95%) at 293K in the embodiments of the present invention.

[0054] Figure 12 This is the AC impedance diagram (293K) of Cage2 / Nafion-10 at different humidities (67-95%) in the embodiments of the present invention.

[0055] Figure 13 This is the relationship diagram of the proton conductivities of Cage2 / Nafion-5 and Cage2 / Nafion-10 varying with humidity in the embodiments of the present invention (293K). Detailed implementation manners

[0056] To make the above objects, features and advantages of the present invention more obvious and understandable, the following will give a detailed description of the specific implementation manners of the present invention in conjunction with the embodiments of the specification.

[0057] The chemical reagents such as isophthalaldehyde and N-bromosuccinimide used in the embodiments of the present invention were all purchased from reagent companies such as Aladdin and Sinopharm, without further purification treatment. The commercial Nafion solution was purchased from J&K Scientific Ltd., and they are all ordinary commercially available products.

[0058] Example 1

[0059] This example provides a synthesis method of a proton conductor Cage2 with a molecular cage structure. The synthetic route is shown in Figure 1 ;

[0060] The specific synthesis steps are as follows:

[0061] (1) Dissolve isophthalaldehyde (2.00 g, 14.9 mmol) in 10 mL of concentrated sulfuric acid and heat to 60 °C. Add N-bromosuccinimide (3.18 g, 17.9 mmol) thereto in batches and react at 60 °C for 4 hours;

[0062] After the reaction is completed, pour the reaction solution into ice water. A white solid precipitates. Filter and wash the filter cake with water and hexane, and dry to obtain 2.21 g of product 2 with a yield of 70%;

[0063] The structural formula of product 2 is:

[0064] (2) Dissolve product 2 (2.13 g, 10 mmol), 4-cyanophenylboronic acid (2.20 g, 15 mmol), and potassium carbonate (5.53 g, 40 mmol) in a mixed solution of tetrahydrofuran (80 mL) and water (40 mL). Under nitrogen protection, add the catalyst tetrakis(triphenylphosphine)palladium (0.578 g, 5% mol), stir and react at 80 °C for 10 hours;

[0065] After the reaction was completed, it was cooled to room temperature, and the organic solvent was removed by rotary evaporation; Dichloromethane (50 mL) and water (20 mL) were successively added to the solid residue, and after sufficient oscillation, it was allowed to stand, the aqueous phase was removed, and the organic phase was washed with water 2 times;

[0066] After the washed organic phase was dried over anhydrous sodium sulfate, filtered, and the organic solvent was removed by distillation, a crude product was obtained;

[0067] The obtained crude product was purified by column chromatography to obtain 1.83 g of a pale yellow solid product 3, with a yield of 78%;

[0068] The structural formula of product 3 is:

[0069]

[0070] (3) Synthesis of Cage1: Product 3 (1.880 g, 8 mmol) and tris(2-aminoethyl)amine (0.789 g, 5.4 mmol) were added to 100 mL of acetonitrile solution, and the reaction was carried out at room temperature for 24 h;

[0071] After the reaction was completed, a pale yellow solid precipitated in the solution. After filtration, the filter cake was washed with acetonitrile and dried under vacuum to obtain a pale yellow solid;

[0072] Subsequently, the solid was dissolved in a mixed solution of dichloromethane and methanol, and sodium borohydride (0.38 g, 10 mmol) was added under an ice bath;

[0073] After reacting at room temperature for 6 hours, the reaction was quenched by adding water, the product in it was extracted with dichloromethane, and then washed twice with 5% aqueous sodium carbonate solution;

[0074] After the washed organic phase was dried over anhydrous sodium sulfate, filtered, and the organic solvent was removed by distillation, 2.31 g of product Cage1 was obtained, with a yield of 96%;

[0075] The structural formula of product Cage1 is:

[0076]

[0077] The 1 1H NMR spectrum of Cage1 (CDCl3, 25 °C, 400 MHz) is shown in Figure 2 ;

[0078] The 13 13C NMR spectrum of Cage1 (CDCl3, 25 °C, 100 MHz) is shown in Figure 3 ;

[0079] (4) Synthesis of Cage2: Excessive phosphoric acid was added to the product Cage1 (0.902 g, 1.0 mmol) to adjust the pH to about 0. After removing water by distillation, a solid precipitated. After filtration and drying, 1.56 g of a white solid, namely the product Cage2, was obtained with a yield of 97%.

[0080] The structural formula of the product Cage2 is:

[0081]

[0082] The 1 1H NMR spectrum (D2O, 25 °C, 400 MHz) of Cage2 is shown in Figure 4 ;

[0083] The 13 13C NMR spectrum (D2O, 25 °C, 100 MHz) of Cage2 is shown in Figure 5 ;

[0084] The mass spectrometry results of compound Cage1 are as follows: MALDI-TOF-HRMS (ESI): m / z calcd for C 57 H 63 N 11 [M + H] + 902.5346, found: 902.5378. The high-resolution mass spectrum (ESI) of Cage1 is shown in Figure 6 .

[0085] The mass spectrometry results of compound Cage2 are as follows: MALDI-TOF-HRMS (ESI): m / z calcd for C 57 H 84 N 11 P7O 28 [M - 6H3PO4] + 1000.5110, found: 1000.4997. The high-resolution mass spectrum (ESI) of Cage2 is shown in Figure 7 .

[0086] Example 2

[0087] A composite membrane was prepared by the solution casting method:

[0088] (1) First, a commercial Nafion solution was heated in an oven at 80 °C for 10 h to obtain dry Nafion resin;

[0089] (2) Then, 4 g and 2 g of the Nafion resin were respectively redissolved in 5 mL of DMF. Secondly, a certain amount of Cage2 was added respectively, and the mass percentage of Cage2 relative to Nafion was 5% and 10%;

[0090] Ultrasonic dispersion for 1 h, stir at room temperature until homogeneous;

[0091] (3) Finally, spread the mixture evenly on a glass plate and heat at 80 °C for 12 h;

[0092] After the composite film is formed, carefully peel it off from the glass plate, soak it in deionized water for storage, and the composite films Cage2 / Nafion-5 and Cage2 / Nafion-10 are obtained, with a thickness of about 0.03 cm.

[0093] (4) Proton conduction performance test

[0094] The proton conductivity of the above-mentioned film was tested by a four-probe electrode device. During the test, the film was clamped in the carbon paper between the electrodes. An electrochemical workstation was used to detect the film impedance, and the final conductivity was calculated according to the following formula:

[0095]

[0096] In the formula, σ (mS·cm -1 ) is the proton conductivity; L (cm) is the film thickness; R (Ω) is the film impedance; S (cm 2 ) is the cross-sectional area of the electrode.

[0097] Before the test, the film was cut into a circle with a radius of 6 mm. The key to the test conditions was to control the humidity and temperature of the film material. When measuring different humidities, different saturated salt solutions were used to simulate different humidities. During the test, the device was placed in a sealed chamber with the required humidity for testing, and the humidity was monitored by a hygrometer. The film material had to be placed in a sealed container for 12 h before testing. When measuring different temperatures, the film was placed in an oven and the temperature was controlled for 1 hour. The test circuit and clips were inserted into the oven through the side opening of the oven for testing.

[0098] The proton conductivities of Cage2 / Nafion-5 at different temperatures were obtained under the condition of 95% constant relative humidity. The experimental data ( Figure 8 and Figure 10 ) showed that its conductivity value showed a gradient upward trend: it was 7.58×10 -4 S / cm at 293 K, and reached a relatively high level of 2.80×10 -3 S / cm at 333 K;

[0099] This phenomenon can be attributed to the increased mobility of water molecules in the high-temperature environment, which significantly enhanced the proton conduction performance of Cage2 / Nafion-5. This value is comparable to the highest proton conductivity of 1.60×10 -3 S / cm reported in porous organic cage compounds.

[0100] In addition, a good Arrhenius linear relationship is presented between the proton conductivity of the membrane and temperature ( Figure 10 ), and the activation energy of Cage2 / Nafion-5 is calculated to be 0.29 eV, which is lower than the threshold of 0.4 eV, indicating the existence of Grotthuss proton conduction mechanism in the system.

[0101] The proton conductivities of Cage2 / Nafion-10 at different temperatures ( Figure 9 and Figure 10 ) show that its conductivity values also present a gradient increasing trend; when the temperature rises to 333 K under 95% RH condition, Cage2 / Nafion-10 obtains a relatively high conductivity of 4.57×10 - 3 S / cm. Combining with its calculated activation energy of 0.12 eV ( Figure 10 ), it indicates that this proton conduction process follows the Grotthuss mechanism of proton hopping. Comparative experiments show that Cage2 / Nafion-10 not only has higher proton conductivity than Cage2 / Nafion-5, but also shows a significantly reduced activation energy.

[0102] The conductivity data of Cage2 / Nafion-5 obtained through the semicircles in the Nyquist plots ( Figure 11 and Figure 13 ) show that: at 293 K temperature, when the relative humidity (RH) increases from 67% to 95%, its conductivity significantly increases from 4.55×10 -5 S / cm to 7.58×10 -4 S / cm. The conductivity value under 95% RH condition is about 16 times that at 67% RH, and this order-of-magnitude difference clearly reveals the significant influence of the change of moisture content with humidity on the conductance characteristics of the material.

[0103] The proton conductivity of Cage2 / Nafion-10 also shows an increasing trend with the increase of relative humidity ( Figure 12 and Figure 13 ), and its value ranges from 7.81×10 -5 S / cm (293 K, 67% RH) to 2.78×10 -3 S / cm (293 K, 95% RH).

[0104] In contrast, Cage2 / Nafion-10 shows higher proton conductivity and significantly lower activation energy than Cage2 / Nafion-5. This is attributed to the more densely distributed H2PO4 - anions in the Cage2 / Nafion-10 material, which can directly act as carriers for proton hopping.

[0105] Based on the above experimental data, it is shown that we have successfully synthesized and experimentally characterized an organic cage salt Cage2 with high proton conductivity. Two composite membranes Cage2 / Nafion-5 and Cage2 / Nafion-10 were prepared by dispersing Cage2 in Nafion resin at different mass fractions through the solution casting method.

[0106] As the temperature increases, the conductivity of the composite membrane increases significantly, indicating that the proton migration rate accelerates under high-temperature environments. In addition, under the condition of increasing humidity, since water molecules provide more abundant hydrogen bond sites, the proton conduction performance of the material also shows an increasing trend. Theoretical calculations show that the activation energies of the two thin films are both lower than 0.4 eV, confirming that their proton transport follows the Grotthuss mechanism. Cage2 / Nafion-10 contains more H2PO4 - anions and water molecules acting as proton carriers, showing more excellent proton conduction performance and lower activation energy than Cage2 / Nafion-5. The research results lay an important foundation for the development of new proton conduction materials based on organic cage structures.

[0107] In this invention, the molecular cage structure prepared in this invention is used as a proton conductor for the first time. There are various types of proton conductor materials. The mainly widely used ones in the market are organic polymer doped membranes, metal-organic framework materials (MOF), porous covalent organic frameworks (COF), and crystalline porous organic molecules. The reported organic cage molecular proton conductors show a relatively high proton conductivity of 1.1×10 -3 S / cm (95% RH) at 30 °C. However, for high-temperature proton exchange membrane materials, their working temperature range is still relatively low and the proton conductivity also needs to be improved. The proton conductor material invented by us can show a higher proton conductivity of 2.78×10 -3 S / cm (95% RH) at 60 °C, showing outstanding technological progress.

[0108] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the present invention.

Claims

1. A proton conductor with a molecular cage structure, characterized in that: The structural formula of the proton conductor with a molecular cage structure is as follows: Wherein, X = H2PO4.

2. The preparation method of the proton conductor with the molecular cage structure according to claim 1, characterized in that: Including, Dissolve reactant 1, isophthalaldehyde, in concentrated sulfuric acid and heat to 60 °C. Add N-bromosuccinimide thereto in batches and react at 60 °C. After the reaction is completed, pour the reaction solution into ice water. A white solid precipitates. Filter and wash the filter cake with water and hexane, and dry to obtain product 2. The structural formula of product 2 is as follows: Dissolve product 2, 4-cyanophenylboronic acid, and potassium carbonate in a mixed solution of tetrahydrofuran and water. Under nitrogen protection, add the catalyst tetrakis(triphenylphosphine)palladium, stir and react at 80 °C for 10 hours. After the reaction is completed, cool to room temperature and remove the organic solvent by rotary evaporation. Add dichloromethane and water to the solid residue in sequence. Vigorously shake and then let stand. Remove the aqueous phase, and wash the organic phase with water twice. Dry the washed organic phase with anhydrous sodium sulfate, filter, and distill off the organic solvent to obtain a crude product. Purify the obtained crude product by column chromatography to obtain a pale yellow solid product 3. The structural formula of product 3 is as follows: Add product 3 and tris(2-aminoethyl)amine to an acetonitrile solution and react at room temperature for 24 h. After the reaction is completed, a pale yellow solid precipitates in the solution. Filter and wash the filter cake with acetonitrile and dry in vacuo to obtain a pale yellow solid. Subsequently, dissolve this solid in a mixed solution of dichloromethane and methanol, and add sodium borohydride under an ice bath. After reacting at room temperature for 6 hours, quench the reaction by adding water. Extract the product therein with dichloromethane, and then wash twice with an aqueous sodium carbonate solution. Dry the washed organic phase with anhydrous sodium sulfate, filter, and distill off the organic solvent to obtain product Cage1. The structural formula of product Cage1 is as follows: Add an excessive amount of phosphoric acid to product Cage1 to adjust the pH to 0. After removing water by distillation, a solid precipitates. Filter and dry to obtain a white solid, which is the proton conductor with a molecular cage structure.

3. The preparation method of the proton conductor with the molecular cage structure according to claim 2, characterized in that: The ratio of the isophthalaldehyde to N-bromosuccinimide is 14.9 mmol: 17.9 mmol.

4. The preparation method of the proton conductor with the molecular cage structure according to claim 2 or 3, characterized in that: The ratio of product 2, 4-cyanophenylboronic acid, and potassium carbonate is 10 mmol: 15 mmol: 40 mmol.

5. The preparation method of the proton conductor with the molecular cage structure as claimed in claim 4, wherein: The ratio of the catalyst tetrakis(triphenylphosphine)palladium to product 2 is 0.578 g: 2.13 g.

6. The preparation method of the proton conductor with the molecular cage structure as described in claim 1, characterized in that: The ratio of product 3, tris(2-aminoethyl)amine, and sodium borohydride is 8 mmol: 5.4 mmol: 10 mmol.

7. The application of the proton conductor with a molecular cage structure as described in claim 1 in the preparation of a high-temperature proton exchange membrane.

8. The application according to claim 7, characterized in that: Including, Heat the commercial Nafion solution to obtain dry Nafion resin. Redissolve the Nafion resin in DMF, add the proton conductor with a molecular cage structure, ultrasonically disperse, and stir at room temperature until homogeneous. Evenly spread the mixture on a glass plate, heat. After the composite membrane is formed, carefully peel it off from the glass plate and soak it in deionized water for storage to obtain the composite membrane.

9. The application according to claim 8, characterized in that: The mass percentage of the proton conductor with a molecular cage structure relative to Nafion is 5% - 10%.

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