KR102567198B1 - Poly(benzopheneone) based polymer for proton exchange membrane of fuel cell, polymer proton exchange membrane for fuel cell, and fuel cell comprising the same - Google Patents

Abstract

The present invention relates to a polymer for a fuel cell proton exchange membrane represented by Structural Formula 1 below. As a result, ion conductivity, mechanical strength, and chemical stability are higher than conventional polymeric proton exchange membranes having sulfate groups.
[Structural Formula 1]

Description

Poly(benzophenone)-based polymer for fuel cell proton exchange membrane, polymer proton exchange membrane for fuel cell including the same, and fuel cell COMPRISING THE SAME}

The present invention relates to a polymer for a fuel cell proton exchange membrane, a polymer proton exchange membrane for a fuel cell including the same, and a fuel cell, and more particularly, a poly(benzophenone)-based polymer for a fuel cell proton exchange membrane that can replace Nafion, which It relates to a polymer proton exchange membrane for a fuel cell and a fuel cell comprising

Green proton exchange membrane fuel cells (PEMFCs) are an effective substitute for fossil fuels. In PEMFC, the polymer electrolyte membrane plays a role in converting H ₂ and an oxidant into electrical energy. Therefore, polymer electrolyte membrane materials are a key research field for fuel cells. Nafions®, a polyfluorosulfonic acid (PFSA)-based membrane, is considered a standard-use material for proton exchange membranes (PEMs), but its application is limited due to its high cost, harsh manufacturing process and difficulty in structural modification. Aromatic hydrocarbon-based polymers with different polymer backbones are already being studied as alternatives to PFSA-based membranes.

Although pre-sulfonation using sulfonated monomers has been found to be more convenient than post-sulfonation of membranes, it is sometimes very difficult to obtain high molecular weight polymers from sulfonated monomers. . In addition, most of these sulfonated polymers exhibit oxidative and hydrolytic stability, but are vulnerable to nucleophile attack because the polymer backbone is based on ether bonds and an acid functional group is attached to the main chain. .

In general, low acidity of sulfonic acid groups is also a cause of poor conductivity of fuel cells. Therefore, researchers have investigated alternative acid functional groups with unfluorinated or partially fluorinated membranes in addition to perfluorosulfonic acid (PFSA). Recently, sulfonimide membranes have become a major concern due to their super gas-phase acidity and excellent thermal stability. A higher charge delocalization ability appears to be responsible for the higher acidity. As a result, polymer membranes using sulfonimide groups are being studied and considered as potential candidates for fuel cell applications. Most sulfonimide membranes also suffer from poor chemical stability due to ether bonds in the main polymer backbone.

Korean Registered Patent Publication No. 10-2195258

An object of the present invention is a poly(benzophenone)-based polymer for a fuel cell proton exchange membrane having high proton conductivity, thermal stability, and chemical stability while being able to replace the conventional unfriendly and expensive Nafion proton exchange membrane, for a fuel cell including the same It is to provide a polymer proton exchange membrane and a fuel cell.

According to one aspect of the present invention,

A polymer for a fuel cell proton exchange membrane represented by Structural Formula 1 is provided.

[Structural Formula 1]

In structural formula 1,

m and n are the number of repeating units,

R ¹ is a fluoro group, a chloro group, a C1 to C20 fluoroalkyl group, or a C1 to C20 chloroalkyl group;

R ² is a hydrogen atom or a C1 to 20 alkyl group.

Preferably,

The compound represented by Structural Formula 1 may be represented by Structural Formula 2 below.

[Structural Formula 2]

In structural formula 2,

m and n are the number of repeating units,

R ¹ is a fluoro group, a chloro group, a C1 to C20 fluoroalkyl group, or a C1 to C20 chloroalkyl group;

R ² is a hydrogen atom or a C1 to 20 alkyl group.

More preferably,

In structural formula 2,

m and n are the number of repeating units,

R ¹ is each independently a fluoro group, a chloro group, a C1 to C10 fluoroalkyl group, or a C1 to C20 chloroalkyl group;

R ² may each independently be a hydrogen atom or a C1 to 10 alkyl group.

Even more preferably,

In Structural Formula 2,

m and n are the number of repeating units,

R ¹ is a fluorine group;

R ² may be a hydrogen atom.

The compound represented by Structural Formula 1 may have a weight average molecular weight (Mw) of 50,000 to 200,000.

The number of repeating units, m:n, may be in a ratio of 50:50 to 70:30.

According to another aspect of the present invention,

(a) preparing poly(benzophenone) (PBP) by C-C coupling reaction of 2,5-dichlorobenzophenone (DCBP) monomer in the presence of a nickel-based catalyst;

(b) preparing sulfonated poly(benzophenone) (S-PBP) by mixing the poly(benzophenone) (PBP) in an organic solvent and then reacting with chlorosulfonic acid; and

(c) reacting the sulfonated poly(benzophenone) (S-PBP) with a compound represented by Structural Formula 3 to prepare a fuel cell proton exchange membrane polymer represented by Structural Formula 1 below; fuel cell comprising: A method for preparing a polymer for a proton exchange membrane is provided.

[Structural Formula 1]

In structural formula 1,

m and n are the number of repeating units,

R ¹ is a fluoro group, a chloro group, a C1 to C20 fluoroalkyl group, or a C1 to C20 chloroalkyl group;

R ² is a hydrogen atom or a C1 to 20 alkyl group.

[Structural Formula 3]

In structural formula 3,

R ³ is a fluoro group, a chloro group, a C1 to C20 fluoroalkyl group, or a C1 to C20 chloroalkyl group;

R ⁴ is a hydrogen atom or a C1 to 20 alkyl group.

In step (a),

The nickel-based catalyst is any one transition metal selected from Zn, Pt, Pd, Ru, Rh, Ni, Fe, Cu, Co, Cr, Au, Re and Zr; and organic ligands.

The organic ligand is selected from among triphenylphosphine, pentamethylcyclopentadiene, cyclooctadiene, benzene, ethylenediamine, and acetylacetonate. It may be any selected one or a derivative thereof.

In step (a),

The C-C coupling reaction

(a-1) dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) to 2,5-dichlorobenzophenone (DCBP) monomer under the nickel catalyst ) Preparing a jelly-like mixture by stirring a mixed solution dissolved in any one solvent selected from;

(a-2) diluting the jelly-like mixture and cooling it to room temperature; and

(a-3) putting the cooled mixture into an acidic aqueous solution to obtain a solid; may include.

Stirring of the mixed solution of step (a-1) may be performed at 80 to 120 ° C.

The reaction of step (b) may be performed while stirring at 70 to 90 °C.

In the above structural formula 3

R ³ is a fluoro group or a C1 to C10 fluoroalkyl group;

R ⁴ may be a hydrogen atom or a C1 to 10 alkyl group.

In the step (c),

(c-1) preparing a reaction mixture by reacting the sulfonated poly(benzophenone) (S-PBP) with thionyl chloride (SOCl ₂ );

(c-2) refluxing the reaction mixture and evaporating the reflux product to obtain a residue; and

(c-2) preparing a fuel cell proton exchange membrane polymer represented by Structural Formula 1 by reacting the residue with a compound represented by Structural Formula 3;

The reaction of step (c-3) may be carried out at 0 to 5 °C.

According to another aspect of the present invention,

A polymer proton exchange membrane for a fuel cell comprising the polymer for a fuel cell proton exchange membrane is provided.

According to another aspect of the present invention,

A method for manufacturing a polymer proton exchange membrane for a fuel cell including the method for manufacturing a polymer for a fuel cell proton exchange membrane is provided.

According to another aspect of the present invention,

A fuel cell including the polymer proton exchange membrane for a fuel cell is provided.

According to another aspect of the present invention,

An electrical device including the fuel cell is provided.

The electric device may be any one selected from a communication device, a transportation device, an energy storage device, and an acoustic device.

The polymer for a fuel cell proton exchange membrane of the present invention can improve ionic conductivity by introducing a sulfonylimide group having a lower acid dissociation constant (pKa) than a sulfate group, and has high mechanical strength by introducing a benzophenone group. Unlike the exchange membrane, since it does not contain an ether group in the polymer main chain, it can inhibit the decomposition of the polymer from oxygen radicals or hydroxide ions generated during fuel cell operation, and can replace the conventional Nafion electrolyte membrane. In addition, when such a polymer for a proton exchange membrane for a fuel cell is applied to a proton exchange membrane for a fuel cell, the electrochemical performance of the fuel cell can be improved.

1 is an FT-IR analysis result according to Experimental Example 1.
2 is a 1H-NMR analysis result for the polymer according to Experimental Example 1.
3 is a 19 F-NMR analysis result according to Experimental Example 1.
4 is an analysis result of the ion exchange capacity (IEC) and water absorption rate (WU) of the proton exchange membrane according to Experimental Example 2.
5 is a proton conductivity analysis result according to Experimental Example 3.
6 is a thermal-oxidation stability analysis result according to Experimental Example 4.
7 is a chemical stability analysis result according to Experimental Example 5.
8 is a result of morphology analysis of a film by an atomic force microscope according to Experimental Example 6.
9 is a cell performance analysis result according to Experimental Example 7;

In the following, various aspects and various embodiments of the present invention are described in more detail. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. However, the following description is not intended to limit the present invention to specific embodiments, and in describing the present invention, if it is determined that the detailed description of related known technologies may obscure the gist of the present invention, the detailed description will be omitted. . Terms used herein are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "comprise" or "having" are intended to indicate that there is a feature, number, step, operation, component, or combination thereof described in the specification, but one or more other features or It should be understood that the presence or addition of numbers, steps, operations, elements, or combinations thereof is not precluded.

Hereinafter, the poly(benzophenone)-based polymer for a fuel cell proton exchange membrane of the present invention will be described.

The poly(benzophenone)-based polymer for a fuel cell proton exchange membrane of the present invention is represented by Structural Formula 1 below.

[Structural Formula 1]

In structural formula 1,

m and n are the number of repeating units,

R ¹ is a fluoro group, a chloro group, a C1 to C20 fluoroalkyl group, or a C1 to C20 chloroalkyl group;

R ² is a hydrogen atom or a C1 to 20 alkyl group.

Preferably,

The compound represented by Structural Formula 1 may be represented by Structural Formula 2 below.

[Structural Formula 2]

In structural formula 2,

m and n are the number of repeating units,

R ¹ is a fluoro group, a chloro group, a C1 to C20 fluoroalkyl group, or a C1 to C20 chloroalkyl group;

R ² is a hydrogen atom or a C1 to 20 alkyl group.

More preferably,

In Structural Formula 2,

m and n are the number of repeating units,

R ¹ is each independently a fluoro group, a chloro group, a C1 to C10 fluoroalkyl group, or a C1 to C20 chloroalkyl group;

R ² may each independently be a hydrogen atom or a C1 to 10 alkyl group.

Even more preferably,

In Structural Formula 2,

m and n are the number of repeating units,

R ¹ is a fluorine group;

R ² may be a hydrogen atom.

Preferably, the compound represented by Structural Formula 2 may have a weight average molecular weight (Mw) of 50,000 to 200,000, preferably 80,000 to 160,000, and more preferably 100,000 to 130,000.

The ratio of m:n, the number of repeating units, may be preferably 30:70 to 90:10, more preferably 40:60 to 80:20, and still more preferably 50:50 to 70:30. When the relative ratio of m is lower than the above ratio, the degree of channel formation for proton conduction may be insufficient because the ratio of the sulfonimide group to the entire polymer for the proton exchange membrane is low, and when the relative ratio of m is higher than the above ratio, the thermal Stability or chemical stability may be reduced.

Hereinafter, a method for preparing a poly(benzophenone)-based polymer for a fuel cell proton exchange membrane according to the present invention will be described.

First, a 2,5-dichlorobenzophenone (DCBP) monomer is subjected to a C-C coupling reaction in the presence of a nickel-based catalyst to prepare poly(benzophenone) (PBP) (step a).

The nickel-based catalyst is any one transition metal selected from Zn, Pt, Pd, Ru, Rh, Ni, Fe, Cu, Co, Cr, Au, Re and Zr; and an organic ligand. It is more preferable to add Zn to the transition metal and use it as a Ni—Zn composite transition metal catalyst.

The organic ligand is selected from among triphenylphosphine, pentamethylcyclopentadiene, cyclooctadiene, benzene, ethylenediamine, and acetylacetonate. It may be any selected one or a derivative thereof, and preferably triphenylphosphine may be used.

The C-C coupling reaction is preferably carried out sequentially according to the method below.

First, 2,5-dichlorobenzophenone (DCBP) monomer was mixed with dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethylformamide (DMF) and dimethylsulfoxide (DMSO) under the nickel-based catalyst. The mixed solution dissolved in any one selected solvent is stirred to prepare a jelly-like mixture (step a-1).

Stirring of the mixed solution is preferably performed at 80 to 120°C, more preferably at 90 to 110°C.

Next, the jelly-like mixture is diluted and cooled to room temperature (step a-2).

The cooled mixture is put into an acidic aqueous solution to obtain a solid (step a-3).

The acid solution is preferably used as an aqueous solution of a strong acid such as hydrochloric acid, nitric acid, or sulfuric acid.

Next, the poly (benzophenone) (PBP) is mixed in an organic solvent and reacted with chlorosulfonic acid to prepare sulfonated poly (benzophenone) (S-PBP) (step b).

In this step, the reaction is preferably carried out at 70 to 90 ° C. while stirring, more preferably at 75 to 85 ° C.

Dichloromethane, dimethylformamide, tetrahydrofuran, ethyl acetate, acetonitrile, dioxane, ethanol and the like can be used as the organic solvent.

Thereafter, the sulfonated poly(benzophenone) (S-PBP) is reacted with a compound represented by Structural Formula 3 to prepare a fuel cell proton exchange membrane polymer represented by Structural Formula 1 below (step c).

[Structural Formula 1]

In structural formula 1,

m and n are the number of repeating units,

R ¹ is a fluoro group, a chloro group, a C1 to C20 fluoroalkyl group, or a C1 to C20 chloroalkyl group;

R ² is a hydrogen atom or a C1 to 20 alkyl group.

[Structural Formula 3]

In structural formula 3,

R ³ is a fluoro group, a chloro group, a C1 to C20 fluoroalkyl group, or a C1 to C20 chloroalkyl group;

R ⁴ is a hydrogen atom or a C1 to 20 alkyl group.

Preferably, in Structural Formula 3,

R ³ is a fluoro group or a C1 to C10 fluoroalkyl group;

R ⁴ may be a hydrogen atom or a C1 to 10 alkyl group.

More preferably, the compound represented by Structural Formula 3 may be fluorosulfonamine (FSO ₂ NH ₂ ).

It is preferable that this step is specifically performed in the following order.

First, a reaction mixture is prepared by reacting the sulfonated poly(benzophenone) (S-PBP) with thionyl chloride (SOCl ₂ ) (step c-1).

Thereafter, the reaction mixture is refluxed, and the reflux product is evaporated to obtain a pasty residue (step c-2).

Next, the residue is reacted with the compound represented by Structural Formula 3 to prepare a fuel cell proton exchange membrane polymer represented by Structural Formula 1 (step c-3).

The reaction of step (c-3) is preferably carried out at 0 to 5°C.

When the reaction is completed, the sulfonimide poly(benzophenone) compound represented by Structural Formula 1 can be finally obtained by putting it in an aqueous alcohol solution.

In addition, the present invention provides a polymer proton exchange membrane for a fuel cell including the poly(benzophenone)-based polymer for a fuel cell proton exchange membrane.

In addition, the present invention provides a method for manufacturing a polymer proton exchange membrane for a fuel cell, including a method for manufacturing a poly(benzophenone)-based polymer for a fuel cell proton exchange membrane.

In addition, the present invention provides a fuel cell including the polymer proton exchange membrane for fuel cells.

In addition, the present invention provides an electric device including the fuel cell.

The electric device may be a communication device, a transportation device, an energy storage device, a sound device, and the like.

Hereinafter, examples according to the present invention will be described in detail.

[Example]

Scheme 1 below schematically shows the synthesis process of poly(benzophenone) according to Preparation Examples 1 to 3 of the present invention.

The SI-PBP polymer was synthesized by CC coupling polymerization of DCBP monomers using a Ni(0) catalyst. The molar ratio of the catalyst plays an important role in obtaining a high molecular weight polymer. Therefore, the molar ratio of the catalyst NiBr ₂ : PPh3 : Zn (1:10:40) was applied to the synthesis of the PBP polymer. In addition, chlorosulfonation of the PBP polymer (S-PBP) was obtained by controlling the amount and time of exposure to chlorosulfonic acid. Thereafter, sulfonimidization was performed using thionyl chloride (SOCl ₂ ) and fluorosulfonamine (FSO ₂ NH ₂ ), respectively.

[Scheme 1]

Hereinafter, a specific manufacturing method is described.

Preparation Example 1: Synthesis of poly(benzophenone) (PBP)

2,5-dichloro benzophenone (DCBP) monomer was synthesized in 2,5-dichloro toluene followed by Friedel-Craft acylation using benzene. NiBr ₂ (0.366g, 1.19mmol), Zn powder (4.54g, 71.68mmol), and triphenylphosphine (2.51g, 9.56mmol) were filled in a three-necked catalyst flask in a glove box, and 2,5-dichlorobenzophenone ( DCBP) monomer (3.0 g, 11.95 mmol) was charged to another flask. DMAc (3-5 mL) was added to the catalyst flask by syringe and stirred with a mechanical stirrer under a nitrogen flow. The solution was stirred at 80° C. until it turned red. The DCBP monomer was then dissolved in DMAc solvent and added to the catalyst flask via a syringe. The mixture was stirred at 100° C. for 12 hours to obtain a viscous dark mixture. The viscous mixture was diluted with 8-10 mL of DMAc and cooled to room temperature. Thereafter, this solution was added to distilled water containing 30% HCl while stirring, and when a solid was formed, it was filtered and washed with distilled water and methanol, respectively. Finally, the white solid polymer, poly(benzophenone) (PBP), was dried in a vacuum oven at 60°C for 12 hours.

Preparation Example 2: Synthesis of sulfonated poly(benzophenone) (SPBP)

First, the PBP polymer (2.0 g, 7.96 mmol) prepared according to Preparation Example 1 was dissolved in chloroform (10 ml) at 25 °C. Concentrated chlorosulfuric acid (3.18 mL, 47.8 mmol) was added slowly at 0 °C and stirred at 80 °C for 6 hours. The black solution was poured into ice water and vigorously stirred to obtain a yellow solid. Finally, the yellow solid polymer was rinsed with distilled water and dried at 60 °C for 24 hours.

Preparation Example 3: Synthesis of sulfonimide poly(benzophenone) (SI-PBP)

A 100mL flask was filled with SPBP polymer (2.0g, 5.66mmol) prepared according to Preparation Example 2, dichloromethane (15mL) and thionyl chloride (SOCl ₂ ) (20mL). The mixture was refluxed with 2 mL DMF at 75° C. for 24 hours, then all solvents were evaporated to obtain a viscous solution. The resulting viscous solution was diluted with dichloromethane (15 mL) and fluorosulfonamine (2.24 g, 22.65 mmol) was added slowly at 0 °C. The mixture was stirred at 25° C. for 12 hours, and the resulting orange solution was added to methanol to obtain sulfonimide poly(benzophenone) polymer (SI-PBP).

Example 1: Preparation of proton exchange membrane (SI-PBP 1)

0.3 g of SI-PBP prepared according to Preparation Example 3 was dissolved in 5 mL DMAc solvent to make a 6% (w/v) solution, and a 3 cm x 3 cm silicone rim was installed on a glass plate, and the solution was placed inside and incubated overnight under an IR lamp. to prepare a SI-PBP1 proton exchange membrane having a thickness of 25 μm.

Example 2: Preparation of proton exchange membrane (SI-PBP 2)

SI-PBP 2 proton having a thickness of 25 μm under the same conditions as in Example 1, except that SI-PBP2 having a fluorosulfonimide group content of 5: 6 was used as compared to the SI-PBP of Preparation Example 3. An exchange membrane was prepared.

Example 3: Preparation of proton exchange membrane (SI-PBP 3)

SI-PBP 3 proton having a thickness of 25 μm under the same conditions as in Example 1, except that SI-PBP3 having a fluorosulfonimide group content of 5: 7 was used as compared to the SI-PBP of Preparation Example 3. An exchange membrane was prepared.

Device Example 1: Single cell manufacturing

A membrane electrode assembly (MEA) having an active area of 25 cm ² was fabricated by a decal method based on a catalyst-coated membrane (CCM). As gas diffusion layers (GDL) on the sides of the anode and cathode, 190 mm thick 20% by weight wet-resistant carbon paper was used.

Carbon-supported Pt was used as the catalyst for both the anode and cathode, and the loading of the catalyst layer was 0.29 mg Pt/cm ² . Thereafter, the catalyst layer was transferred to the SI-PBP 1 proton exchange membrane of Example 1 by a decal method at 120 ° C. and 10 MPa for 5 minutes to make CCM. GDLs were placed on the anode and cathode sides of the CCM to form a membrane electrode assembly (MEA), and a single cell was assembled.

Device Example 2: Single cell manufacturing

A single cell was manufactured under the same conditions as in Device Example 1, except that the SI-PBP 2 proton exchange membrane of Example 2 was used instead of the SI-PBP 1 proton exchange membrane of Example 1.

Device Example 3: Single cell manufacturing

A single cell was manufactured under the same conditions as in Device Example 1, except that the SI-PBP 3 proton exchange membrane of Example 2 was used instead of the SI-PBP 1 proton exchange membrane of Example 1.

[Test Example]

Experimental Example 1: FT-IR analysis

1 is a FT-IR (Fourier Transform Infrared Spectrometer) analysis result for the polymer prepared according to Preparation Examples 1 to 3. According to Figure 1, a wide stretching frequency in the range of 2800-3600 cm ^-1 corresponds to the -OH vibration frequency of the S-PBP polymer. The stretching frequencies at 1420 and 1190 cm ^-1 correspond to the S = O group, whereas for the C = O bond the frequency at 1680 cm ^-1 corresponds.

2 is a 1H-NMR analysis result for the polymers of Preparation Examples 1 to 3. According to this, the peak around 6.50-7.78 ppm corresponds to the proton of the aromatic ring for the PBP and SPBP polymers. The -SO ₃ H peak of the SPBP polymer is observed upfield at 4.0 ppm due to the binding with water and solvent DMSO. However, the aromatic proton peak of the SI-PBP polymer was shifted downfield at 6.50–8.60 ppm due to the delocalization performance of the sulfonimide anion. A characteristic large NH peak was observed at 4.90–5.70 ppm.

3 is a 19 F-NMR analysis result of the polymers of Preparation Examples 1 to 3. According to this, as a characteristic 19F peak appears near -162 ppm, it can be confirmed that the sulfonylimide group is attached to the polymer backbone.

Experimental Example 2: Analysis of ion exchange capacity (IEC), water absorption rate (WU) and dimensional stability

4 is an analysis result of ion exchange capacity (IEC) and water absorption rate (WU) of the proton exchange membranes prepared according to Examples 1 to 3, respectively. According to this, the water absorption rate gradually increased from 22.72 to 64.29%, and the ion exchange capacity also increased from 1.85 to 2.30 meq./g.

In Tables 1 and 2 below, the properties of the proton exchange membranes prepared in Examples 1 to 3 and Nafion 211® are compared and summarized.

The charge delocalization ability of sulfonimide acid groups is related to the higher water content of SI-PBP membranes. The SI-PBP membrane showed relatively lower dimensional stability (through-plane (Δt) and in-plane (Δl) changes) than Nafion 211®. SI-PBP membranes showed higher Dt (7.5%, 12.5% and 34.0%) and Δl (4.81%, 8.0% and 16.17%) values, whereas Nafion 211® showed (Δt = 31.98 and Δl = 14.2%). . The Δl value of the SI-PBP membrane was significantly lower than the Δt value due to the C-C bonded aromatic rigid polymer backbone.

Experimental Example 3: Proton Conductivity Analysis

5 shows the proton conductivity of the SI-PBP film according to the temperature change (30-90 ° C) (a) and the relative humidity change (30-90%). According to this, the SI-PBP-3 membrane of Example 3 exhibited a much higher proton conductivity (107.07 mS / cm) than Nafion 211® (104.5 mS / cm) at 90 ° C and 90% relative humidity, and the SI of Example 2 -PBP 2 showed similar proton conductivity (94.80 mS/cm) to Nafion 211® (104.5 mS/cm) under the same conditions. The proton conductivities of the SI-PBP membranes of Examples 1 to 3 increased with increasing humidity. The higher acidity and location of the sulfonimide groups in the pendant benzophenone ring can increase the proton conductivity of the SI-PBP membrane by forming highly distinct ion channels for proton conduction.

Experimental Example 4: Thermal-Oxidative Stability Analysis

6 shows thermal decomposition curves of the SI-PBP membranes of Examples 1 to 3 and the PBP membranes to which the sulfonimide group is not bonded in air. According to this, the PBP polymer showed one-step thermal decomposition at about 380 °C, and the SI-PBP film showed three-step degradation. Thermal decomposition in the range of 200–330, 340–475 and 475–610 °C accounts for the conversion of sulfonimides to sulfonic acid groups, removal of -SO ₃ H groups and decomposition of the polymer backbone, respectively. Remarkably, the most advantageous point of the SI-PBP polymer is that it conducts protons in two steps, -SO ₂ NHSO ₂ - groups and -SO ₃ H groups before the main polymer backbone is destroyed. In addition, the SI-PBP polymer is stable up to 550 °C, and the C-C bonded aromatic backbone is mainly related to the excellent thermal stability of the SI-PBP membrane.

Experimental Example 5: Chemical Stability Analysis

Figure 7 shows the results of measuring the weight loss over time at 80 ℃ for 9 hours in order to measure the chemical stability of the SI-PBP membrane prepared according to Examples 1 to 3 using Fenton's reagent. According to this, all SI-PBP membranes of Examples 1 to 3 showed excellent chemical stability compared to sulfonated poly(arylene ethersulfone) (SPAES 40). The C-C polymeric backbone is less susceptible to free radical attack and the presence of fluorine atoms in the sulfonimide group may indicate higher chemical stability of the SI-PBP membrane.

Experimental Example 6: Analysis of membrane morphology

8 shows the surface appearance of the trapping mode of SI-PBP by atomic force microscopy (AFM). According to this, the brown compartment represents the hydrophobic aromatic domain, while the dark black channel-like portion represents the hydrophilic sulfonimide group with water in the SI-PBP membrane. In general, the contents of the polymer backbone and acid moiety have a great influence on the morphology of the polymer membrane. Therefore, since the SI-PBP 3 membrane of Example 3 contains a larger number of sulfonylimide groups than the others, a remarkably large number of hydrophilic channels appear. In contrast, since the SI-PBP 1 membrane of Example 1 has relatively few sulfonylimide groups, it can be confirmed that the ion channels are less developed.

Experimental Example 7: Cell Performance Analysis

9 is a polarization curve for single cell performance including SI-PBP films prepared according to Device Examples 1 to 3; According to this, the cell including the SI-PBP 3 film of Device Example 3 showed higher maximum power density (0.638 W/cm ² ) than the cell including Nafion 211® (0.62 W/cm ² ). The cell including SI-PBP 1 of Device Example 1 and the cell including SI-PBP 2 of Device Example 2 exhibited cell performance similar to that of the cell containing Nafion 211® over the entire current density range.

Although the embodiments of the present invention have been described above, those skilled in the art can add, change, delete, or add components within the scope not departing from the spirit of the present invention described in the claims. The present invention can be variously modified and changed by the like, and this will also be said to be included within the scope of the present invention.

Claims (20)

A polymer for a fuel cell proton exchange membrane represented by Structural Formula 1 below;
[Structural Formula 1]

In structural formula 1,
m and n are the number of repeating units,
R ¹ is a fluoro group, a chloro group, a C1 to C20 fluoroalkyl group, or a C1 to C20 chloroalkyl group;
R ² is a hydrogen atom or a C1 to 20 alkyl group. According to claim 1,
The compound represented by Structural Formula 1 is a polymer for a fuel cell proton exchange membrane, characterized in that represented by Structural Formula 2 below;
[Structural Formula 2]

In structural formula 2,
m and n are the number of repeating units,
R ¹ is a fluoro group, a chloro group, a C1 to C20 fluoroalkyl group, or a C1 to C20 chloroalkyl group;
R ² is a hydrogen atom or a C1 to 20 alkyl group. According to claim 2,
In structural formula 2,
m and n are the number of repeating units,
R ¹ is each independently a fluoro group, a chloro group, a C1 to C10 fluoroalkyl group, or a C1 to C20 chloroalkyl group;
A polymer for a fuel cell proton exchange membrane, wherein each R ² is independently a hydrogen atom or a C1 to 10 alkyl group. According to claim 3,
In Structural Formula 2,
m and n are the number of repeating units,
R ¹ is a fluorine group;
A polymer for a fuel cell proton exchange membrane, wherein R ² is a hydrogen atom. According to claim 1,
The compound represented by Structural Formula 1 has a weight average molecular weight (Mw) of 50,000 to 200,000. According to claim 1,
The number of repeating units, m:n, is a polymer for a fuel cell proton exchange membrane, characterized in that the ratio is 50:50 to 70:30. (a) preparing poly(benzophenone) (PBP) by CC coupling reaction of 2,5-dichlorobenzophenone (DCBP) monomer in the presence of a nickel-based catalyst;
(b) preparing sulfonated poly(benzophenone) (S-PBP) by mixing the poly(benzophenone) (PBP) in an organic solvent and then reacting with chlorosulfonic acid; and
(c) reacting the sulfonated poly(benzophenone) (S-PBP) with a compound represented by Structural Formula 3 to prepare a fuel cell proton exchange membrane polymer represented by Structural Formula 1 below; fuel cell comprising: Method for producing a polymer for a proton exchange membrane.
[Structural Formula 1]

In structural formula 1,
m and n are the number of repeating units,
R ¹ is a fluoro group, a chloro group, a C1 to C20 fluoroalkyl group, or a C1 to C20 chloroalkyl group;
R ² is a hydrogen atom or a C1 to 20 alkyl group.
[Structural Formula 3]

In structural formula 3,
R ³ is a fluoro group, a chloro group, a C1 to C20 fluoroalkyl group, or a C1 to C20 chloroalkyl group;
R ⁴ is a hydrogen atom or a C1 to 20 alkyl group. According to claim 7,
In step (a),
The nickel-based catalyst is any one transition metal selected from Zn, Pt, Pd, Ru, Rh, Ni, Fe, Cu, Co, Cr, Au, Re and Zr; and an organic ligand. According to claim 8,
The organic ligand is selected from among triphenylphosphine, pentamethylcyclopentadiene, cyclooctadiene, benzene, ethylenediamine, and acetylacetonate. A method for producing a polymer for a fuel cell proton exchange membrane, characterized in that the selected one or a derivative thereof. According to claim 7,
In step (a),
The CC coupling reaction is
(a-1) dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) to 2,5-dichlorobenzophenone (DCBP) monomer under the nickel catalyst ) Preparing a jelly-like mixture by stirring a mixed solution dissolved in any one solvent selected from;
(a-2) diluting the jelly-like mixture and cooling it to room temperature; and
A method for producing a polymer for a proton exchange membrane in a fuel cell, comprising: (a-3) adding the cooled mixture to an acidic aqueous solution to obtain a solid. According to claim 10,
The method for producing a polymer for a fuel cell proton exchange membrane, characterized in that the stirring of the mixed solution in step (a-1) is performed at 80 to 120 ° C. According to claim 7,
The reaction of step (b) is a method for producing a polymer for a fuel cell proton exchange membrane, characterized in that carried out while stirring at 70 to 90 ℃. According to claim 7,
In the above structural formula 3
R ³ is a fluoro group or a C1 to C10 fluoroalkyl group;
A method for producing a polymer for a fuel cell proton exchange membrane, wherein R ⁴ is a hydrogen atom or a C1 to 10 alkyl group. According to claim 7,
In the step (c),
(c-1) preparing a reaction mixture by reacting the sulfonated poly(benzophenone) (S-PBP) with thionyl chloride (SOCl ₂ );
(c-2) refluxing the reaction mixture and evaporating the reflux product to obtain a residue; and
(c-2) preparing a fuel cell proton exchange membrane polymer represented by structural formula 1 by reacting the residue with a compound represented by structural formula 3; manufacturing method. According to claim 14,
The reaction of step (c-3) is a method for producing a polymer for a fuel cell proton exchange membrane, characterized in that carried out at 0 to 5 ℃. A polymer proton exchange membrane for a fuel cell comprising the polymer for a fuel cell proton exchange membrane according to any one of claims 1 to 6. A method for manufacturing a polymer proton exchange membrane for a fuel cell, comprising the method for manufacturing a polymer for a fuel cell proton exchange membrane according to any one of claims 7 to 15. A fuel cell comprising the polymer proton exchange membrane for a fuel cell of claim 16. An electrical device comprising the fuel cell of claim 18 . According to claim 19,
The electrical device according to claim 1 , wherein the electrical device is any one selected from a communication device, a transportation device, an energy storage device, and an acoustic device.