Electrolyte membrane, method for producing electrolyte membrane, and membrane electrode assembly

Abstract

This electrolyte membrane comprises an electrolyte and a fullerene derivative having the structure in formula (1) (where FLN is fullerene or a derivative thereof, R 1 is an added group containing one or more carbon atoms, R 2 and R 3 are each independently a substituent containing one or more polar groups; n1≥1; n2≥1; and n3≥0).

Description

Electrolyte membrane, method for manufacturing electrolyte membrane, and membrane electrode assembly

[0001] The present disclosure relates to an electrolyte membrane, a method for manufacturing an electrolyte membrane, and a membrane electrode assembly.

[0002] In solid polymer electrolyte fuel cells, when radicals such as hydroxyl radicals are generated from by-reactants such as hydrogen peroxide through the Fenton reaction, the hydroxyl radicals react with the solid polymer electrolyte membrane, resulting in degradation of the solid polymer electrolyte membrane.

[0003] To solve this problem, cerium ions are added to fuel cells as a radical quencher to eliminate the generated hydroxyl radicals. However, the cerium ions dissolve and migrate during fuel cell operation, reducing their function as a radical quencher and resulting in durability problems (see, for example, Non-Patent Document 1).

[0004] Sophia University, Research and Development of Radical Quenchers Aiming for High Durability, [online], Internet <URL: https: / / www.nedo.go.jp / content / 100937530.pdf>

[0005] Fullerenes have been attracting attention as radical quenchers with excellent durability. The present inventors have newly developed fullerene derivatives that can be suitably used as radical quenchers, and have succeeded in producing electrolyte membranes with excellent properties.

[0006] The present disclosure has been made in view of these problems, and an object of the present disclosure is to provide an electrolyte membrane having excellent properties.

[0007] In order to solve the above problems, an electrolyte membrane according to an embodiment of the present disclosure comprises an electrolyte and a catalyst represented by the formula (1) (wherein FLN is fullerene or a derivative thereof, and R １ is an additional group containing one or more carbon atoms, and R ２ and R ３ are each independently a substituent containing one or more polar groups, and n1≧1, n2≧1, and n3≧0.

[0008] Another aspect of the present disclosure is a method for producing an electrolyte membrane, the method comprising: mixing an electrolyte with a compound represented by formula (1): (wherein FLN is fullerene or a derivative thereof, and R １ is an additional group containing one or more carbon atoms, and R ２ and R ３ are each independently a substituent containing one or more polar groups, and n1 ≧ 1, n2 ≧ 1, and n3 ≧ 0.) and a solution obtained by dissolving the fullerene derivative in a polar solvent to form an electrolyte membrane containing the electrolyte and the fullerene derivative.

[0009] Yet another aspect of the present disclosure is a membrane electrode assembly, which includes the above-described electrolyte membrane, a cathode catalyst layer disposed on one side of the electrolyte membrane, and an anode catalyst layer disposed on the other side of the electrolyte membrane.

[0010] According to the present disclosure, an electrolyte membrane having excellent properties can be provided.

[0011] 1-1 is a diagram showing a synthetic route for the fullerene derivative of Example 1-1; 2-2 is a diagram showing a synthetic route for the fullerene derivative of Example 1-2; 3-3 is a diagram showing a synthetic route for the fullerene derivative of Example 1-3; 4-4 is a diagram showing a synthetic route for the fullerene derivative of Example 1-5; 5-6 is a diagram showing a synthetic route for the fullerene derivative of Example 1-6; 6-7 is a diagram showing the results of measuring the fluorescence spectrum of the fullerene derivative; 7-8 is a diagram showing the results of measuring the fluorescence spectrum of the fullerene derivative; 8-9 is a diagram showing the mass spectrum of the fullerene derivative; 9-10 is a diagram showing the mass spectrum of the fullerene derivative; 10-11 is a diagram showing the solubility of the fullerene derivative in a solvent; 11-12 is a diagram showing the infrared spectrum of the fullerene derivative; 11-13 is a diagram showing the infrared spectrum of the fullerene derivative; 11-14 is a diagram showing the infrared spectrum of the fullerene derivative; 11-15 is a diagram showing the powder X-ray diffraction pattern of the fullerene derivative; 11-16 is a diagram showing the results of thermogravimetric analysis and differential thermal analysis of the fullerene derivative; 11-17 is a diagram showing a photograph and film thickness of an electrolyte membrane; 11-18 is a diagram showing a photograph, a microscope photograph, and film thickness of an electrolyte membrane; 11-19 is a diagram showing a photograph and film thickness of an electrolyte membrane; 1 is a diagram showing the water content and proton conductivity of an electrolyte membrane. 2 is a diagram showing the water content and proton conductivity of an electrolyte membrane. 3 is a diagram showing the water content and proton conductivity of an electrolyte membrane. 4 is a diagram showing the water content and proton conductivity of an electrolyte membrane. 5 is a diagram showing the results of a Fenton test of an electrolyte membrane. 6 is a diagram showing the results of a Fenton test of an electrolyte membrane. 7 is a diagram showing the results of a Fenton test of an electrolyte membrane. 8 is a diagram showing the results of a Fenton test of an electrolyte membrane. 9 is a diagram showing the results of an OCV test. 10 is a diagram showing the amount of fluoride ion discharged in an OCV test. 11 is a diagram showing the amount of fluoride ion discharged in an OCV test. 12 is a diagram showing the OCV in an OCV test. 13 is a diagram showing the OCV in an OCV test. 14 is a diagram showing the tensile strength of a membrane to which a fullerene derivative of an example has been added. 15 is a diagram showing the elongation of a membrane to which a fullerene derivative of an example has been added. 16 is a diagram showing the Young's modulus of a membrane to which a fullerene derivative of an example has been added. 17 is a diagram showing the synthesis routes of the fullerene derivatives of Examples 1-7, 1-8, and 1-9. 1 shows the synthesis routes of the fullerene derivatives of Examples 1-10 and 1-11, and FIG. 2 shows the synthesis routes of the fullerene derivatives of Examples 1-12.1 is a diagram showing the solubility of fullerene derivatives in solvents. It is a diagram showing the molecular structures of the fullerene derivatives of Examples 1-7 and 1-8 determined by single crystal X-ray structural analysis. It is a diagram showing the infrared spectra of the fullerene derivatives of Examples 1-7, 1-8, and 1-9. It is a diagram showing photographs and film thicknesses of the electrolyte membranes of Examples 2-11, 2-12, 2-13, and 2-14. It is a diagram showing the water content and proton conductivity of the electrolyte membranes of Examples 2-11, 2-12, 2-13, and 2-14. It is a diagram showing the results of an OCV test of a membrane electrode assembly including an electrolyte membrane of an Example. It is a diagram showing the results of an OCV test of a membrane electrode assembly including an electrolyte membrane of an Example. It is a diagram showing the amount of fluoride ion emission in an OCV test of a membrane electrode assembly including an electrolyte membrane of an Example. It is a diagram showing the amount of fluoride ion emission in an OCV test of a membrane electrode assembly including an electrolyte membrane of an Example.

[0012] The electrolyte membrane of the present disclosure includes an electrolyte and a fullerene derivative that is highly soluble in water.

[0013] Fullerene derivatives are chemically stable, and their migration is suppressed by their interaction with the electrolyte, allowing them to maintain their radical quenching performance for a long period of time. Furthermore, fullerene derivatives eliminate hydroxyl radicals generated during fuel cell operation and are themselves hydroxylated, but are subsequently reduced by the supplied hydrogen, regenerating the π-conjugated system. Therefore, the radical quenching ability of fullerene derivatives is sustained, and they act catalytically as radical quenchers. This allows them to maintain their radical quenching ability for a long period of time. Therefore, adding fullerene derivatives as radical quenchers to electrolyte membranes can improve the durability of the electrolyte membrane.

[0014] Conventionally known fullerene derivatives have extremely low solubility in polar solvents such as water, so when an electrolyte membrane is produced, they do not dissolve in the electrolyte solution but aggregate and are unevenly dispersed in the electrolyte membrane, resulting in deterioration of the electrolyte membrane in regions where the fullerene derivative is almost absent due to reaction with radicals.

[0015] In contrast, the fullerene derivative contained in the electrolyte membrane of the present disclosure has significantly high solubility in polar solvents such as water, as will be described later, and can be dissolved in the electrolyte solution, allowing it to be uniformly dispersed throughout the electrolyte membrane. This makes it possible to suppress reactions with radicals generated during operation throughout the electrolyte membrane, thereby improving the durability of the electrolyte membrane.

[0016] The electrolyte membrane of the present disclosure may include any type of electrolyte that can be used in a fuel cell. When the fuel cell is a polymer electrolyte fuel cell (PEFC), the electrolyte may be a fluorine-based polymer having sulfonic acid groups, such as Nafion (registered trademark).

[0017] The electrolyte membrane of the present disclosure includes a fullerene derivative having a structure of formula (1).

[0018] The fullerene derivative having the structure of formula (1) exhibits high solubility in polar solvents, particularly water. This is because the additional group R bonded to the fullerene １ R bonded to ２ polar groups such as hydroxyl groups and alkoxy groups contained in ３ This is thought to be due to the affinity between the polar groups such as hydroxyl groups and alkoxy groups contained in the fullerene and the polar solvent. １ R bonded to ２ and polar groups such as hydroxyl groups and alkoxy groups contained in R ３ It is believed that the solubility in water is further increased by the presence of two types of polar groups, such as a hydroxyl group and an alkoxy group, which have different affinity mechanisms with polar solvents. Some fullerene derivatives are known that have only hydroxyl groups bonded to substituents bonded to fullerenes, or only hydroxyl groups bonded directly to fullerenes, but the water solubility of the fullerene derivatives of the present disclosure is significantly higher than that of these known fullerene derivatives, as will be shown in the examples described below.

[0019] In formula (1), FLN is a fullerene or a derivative thereof. ６０ , C ７０ , C ７２ , C ７４ , C ７６ , C ７８ , C ８０ , C ８２ , C ８４ , C ８６ , C ８８ , C ９０ and the like. The derivative refers to a compound that has been modified to an extent that the structure and properties of the parent compound are not significantly changed, such as by introducing a functional group, oxidation, reduction, or atomic substitution. The fullerene derivative may be a compound in which a functional group such as an alkyl group, a heteroalkyl group, an alkenyl group, a heteroalkenyl group, an alkynyl group, a heteroalkynyl group, a cycloalkyl group, a heterocycloalkyl group, an aryl group, a heteroaryl group, a carbonyl group, a carboxy group, a cyano group, a hydroxy group, a thiol group, an amino group, an imino group, a nitro group, or a halogen atom has been introduced into the fullerene, a compound in which a metal atom, a nitrogen atom, or the like is encapsulated in the fullerene, or a compound having a structure in which an alkali metal or the like is intercalated into the fullerene.

[0020] In formula (1), R １ is any additional group containing one or more carbon atoms. １ may include alkyl groups, heteroalkyl groups, alkenyl groups, heteroalkenyl groups, alkynyl groups, heteroalkynyl groups, cycloalkyl groups, heterocycloalkyl groups, aryl groups, heteroaryl groups, and the like. R １ may be a phenyl group having one or more substituents, such as hydroxyl, alkoxy, carboxyl, sulfonate, phosphoryl, phosphate, alkyl, heteroalkyl, alkenyl, heteroalkenyl, alkynyl, or heteroalkynyl groups.

[0021] In formula (1), R １ may contain one or more polar groups. ２ In addition, R １may contain one or more polar groups.

[0022] In formula (1), R ２ and R ３ are each independently any substituent containing a polar group. ２ and R ３ each independently represents a polar group such as OH, COOH, or SO ３ H, OR ５ (R ５ is an alkyl group such as a methyl group or an ethyl group), OSO ３ H, PO(OH) ２ , OPO(OH) ２ The H contained in these may be substituted with one or more metal atoms (such as Na, K, or Ca) or alkyl groups. ３ may be OH, ONa, OK, etc.

[0023] In formula (1), n1 ≧ 1. n1 may be 1 or 2.

[0024] In formula (1), n2 ≧ 1. n2 may be an integer of 1 or more. For example, a Grignard reagent (R ２ ) ｎ１ R １ MgX is reacted with fullerene to form R １ (R ２ ) ｎ１ When introducing n2, n2 may be 5. n2 may be the same value throughout the fullerene derivative or may vary between molecules. When n2 varies between molecules, n2 may be an average value. n2 may be evaluated based on mass spectrometry as described below.

[0025] In formula (1), n3≧0. n3 may be an integer of 0 or greater. n3 may be 1 to 13. As will be described later, n3 may be evaluated based on the measurement results of a fluorescence spectrum or a mass spectrum (MS).

[0026] In formula (1), F １ is a hydrogen atom or any substituent containing one or more carbon atoms. １represents a hydrogen atom, an alkyl group, a heteroalkyl group, an alkenyl group, a heteroalkenyl group, an alkynyl group, a heteroalkynyl group, a cycloalkyl group, a heterocycloalkyl group, an aryl group, a heteroaryl group, a functional group (PO ３ H ２ , PO(OEt) ２ The pentaaddition reaction may be carried out to form a fullerene having R １ (R ２ ) ｎ１ When introducing F1, F1 may be bonded to the five-membered ring in the middle of the five added substituents.

[0027] In formula (1), n4 ≥ 0. n4 may be an integer of 0 or greater.

[0028] In formula (1), n2 substituents R １ (R ２ ) ｎ１ is bonded to a carbon atom belonging to one of the two hemispheres obtained by dividing the fullerene in half by a plane passing through the center of the fullerene, and n3 substituents R ３ is n2 substituents R １ (R ２ ) ｎ１ As will be described later, n2 substituents R １ (R ２ ) ｎ１ By reacting an alkali with the fullerene or its derivative into which n3 substituents R ３ By introducing five R into the fullerene through the above-mentioned pentad addition reaction, a fullerene derivative having the above-mentioned structure can be obtained. １ (R ２ ) ｎ１ In the quintuple adduct, five R atoms are concentrated in one hemisphere. １ (R ２ ) ｎ１ Since n3 substituents R ３ is introduced into the other hemisphere. １ (R ２ ) ｎ１ is a bulky substituent, n3 substituents R ３Due to steric hindrance, n2 substituents R are mainly introduced in the region of the other hemisphere closer to the pole than to the equator. １ (R ２ ) ｎ１ and n3 substituents R ３ However, it is thought that the solubility in polar solvents is improved by the uneven distribution of the ions in the other hemisphere.

[0029] The fullerene derivative of the present disclosure may have a structure of formula (2).

[0030] The fullerene derivative of formula (2) is a compound represented by the formula (1) in which R １ is a phenyl group, and n2 is 5. ２ , R ３ , n1, n3, and n4 are the same as in equation (1).

[0031] The method for producing the fullerene derivative is to add n2 additional groups R １ (R ２ ) ｎ１ (where R １ is an additional group containing one or more carbon atoms, and R ２ is a substituent containing one or more polar groups, and n1≧1 and n2≧1. １ (R ２ ) ｎ１ Introduced into fullerene or its derivative is n3 substituents R ３ (where R ３ is a substituent containing a polar group, and n2≧0.

[0032] The first step is to react fullerene or its derivative with a Grignard reagent (R ２ ) ｎ１ R １ MgX (where X is a halogen) and copper salt CuX.SMe ２ In this case, five additional groups R １ (R ２ ) ｎ１ is introduced into fullerene or its derivative.

[0033] The second step is to add n2 additional groups R １ (R ２ ) ｎ１ The alkali may include a step of reacting an alkali with the fullerene or its derivative into which n3 substituents R have been introduced. The alkali may be sodium hydroxide, potassium hydroxide, tetrabutylammonium hydroxide, or the like. In this case, n3 substituents R ３ is n2 additional groups R １ (R ２ ) ｎ１ is bonded to a carbon atom in a different hemisphere than the carbon atom to which it is bonded.

[0034] The second step is to add n2 additional groups R １ (R ２ ) ｎ１ The method may include a step of reacting iron and hydrogen peroxide with the fullerene or derivative thereof to which n3 hydroxyl groups have been introduced. In this case, n3 hydroxyl groups are introduced by the Fenton reaction.

[0035] The fullerene derivative of the present disclosure may have a structure of formula (3).

[0036] In formula (3), R ４ may be an alkyl group (such as a methyl group, an ethyl group, a propyl group, or a butyl group), an alkyl group having a functional group, or the like. ２ is SO ３ H, OSO ３ It may be H, OH, or a group in which H contained therein is substituted with a metal atom (such as Na, K, or Ca), an alkyl group, etc. n5 may be 1 to 14.

[0037] The method for producing the fullerene derivative may include a step of reacting a cyclic ester or a cyclic ether with a fullerene or a derivative thereof. At this time, a sodium dispersion may be reacted. In this case, one or more substituents R ４ F ２ will be introduced.

[0038] The fullerene derivative of the present disclosure may have a structure of formula (4).

[0039] Formula (4) is a compound in which the phenyl group of formula (2) is replaced by R ６ It is a generalization of R ６ R may be an aryl group such as a phenyl group, a biphenyl group, or a naphthyl group, or a heteroaryl group such as a thienyl group. ２ , R ３ , n1, n3, and n4 are the same as in equation (1).

[0040] The electrolyte membrane of the present disclosure may further contain cerium ions. In conventional electrolyte membranes, the added cerium ions have been problematic in that they are lost due to migration. However, in the electrolyte membrane of the present disclosure, R １ (R ２ ) ｎ１ or R ３ Since the loss of cerium ions from the electrolyte membrane can be suppressed by the interaction with R, the radical quenching ability of cerium ions can be maintained, and the durability of the electrolyte membrane can be further improved. １ (R ２ ) ｎ１ When the fullerene derivative is introduced with at least two of them, they may act as chelating ligands to form a chelate complex with cerium ions, thereby further suppressing the outflow of cerium ions.

[0041] The method for producing an electrolyte membrane according to the present disclosure includes forming an electrolyte membrane containing an electrolyte and a fullerene derivative, the electrolyte and the fullerene derivative being readily soluble in a polar solvent, using a solution obtained by dissolving the electrolyte and the fullerene derivative in a polar solvent. The fullerene derivative may be any of the fullerene derivatives described above.

[0042] The membrane electrode assembly of the present disclosure includes the above-described electrolyte membrane, a cathode catalyst layer disposed on one side of the electrolyte membrane, and an anode catalyst layer disposed on the other side of the electrolyte membrane.

[0043] Example 1 First, an example of the fullerene derivative constituting the electrolyte membrane of the present disclosure will be described.

[0044] [Example 1-1] Figure 1 shows the synthesis route of the fullerene derivative of Example 1-1. Intermediates and final products are denoted by the abbreviations shown in the figure.

[0045] [Synthesis of PhOMe-10] An organocopper reagent was prepared by adding tetrahydrofuran (THF, 30 mL) to copper(I) bromide dimethyl sulfide complex (4.67 g, 22.4 mmol), followed by a THF solution (16 equiv.) of 3,5-dimethoxyphenylmagnesium bromide. To this solution was added a solution of fullerene

[60] (1.03 g, 1.43 mmol) in ortho-dichlorobenzene (oDCB) (30 mL), followed by stirring at room temperature. After adding saturated aqueous ammonium chloride, the mixture was filtered through a short silica gel column and subjected to vacuum distillation using a rotary evaporator. The crude product was reprecipitated with acetone / hexane. PhOMe-10 (1.62 g, 84%) was obtained as a red powder.

[0046] [Synthesis of PhOH-10] PhOMe10 (652 mg) was dissolved in dichloromethane (60 mL). To this solution was added a boron tribromide dichloromethane solution (1 M, 9 mL) in small portions. After 15 minutes, the reaction was quenched with cold water and extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution and then evaporated under reduced pressure using a rotary evaporator. The crude product was reprecipitated with acetone / hexane. PhOH-10 was obtained as a red powder.

[0047] [Synthesis of PhOH-10-OH-B] PhOH-10 (502.5 mg) was dissolved in ethanol (15 mL), and 0.2 M aqueous sodium hydroxide solution (12 mL) and tetrabutylammonium hydroxide (37% methanol solution) (3 mL) were added, followed by stirring at room temperature. After 45 minutes, precipitation was carried out with water / ethanol to obtain solid PhOH-10-OH-B (FLN=C ６０ , R １ = Ph, R ２ =R ３ = OH or ONa, F １ = H, n1 = 2, n2 = 5, n4 = 1) was recovered.

[0048] [Synthesis of PhOH-10-OH-C] 3M hydrochloric acid was added little by little to an aqueous solution of PhOH-10-OH-B to make it acidic. The solution was distilled under reduced pressure using a rotary evaporator to remove water, and PhOH-10-OH-C was obtained. PhOH-10-OH-C was obtained by the R ２ and R ３ All of these have been converted to OH.

[0049] [Synthesis of PhOH-10-OH-D] PhOH-10-OH-C was dissolved in pure water, placed in a dialysis tube (benzoylation, Avg. flat width 32 mm, Sigma Aldrich), and immersed in a beaker containing pure water. The water in the beaker was replaced every day and allowed to stand for one week. After that, the solution was distilled under reduced pressure using a rotary evaporator to remove the water, yielding PhOH-10-OH-D. PhOH-10-OH-D was obtained by purifying PhOH-10-OH-C.

[0050] [Example 1-2] Figure 2 shows the synthesis route of the fullerene derivative of Example 1-2. Intermediates and final products are denoted by the abbreviations shown in the figure.

[0051] [Synthesis of PhCOOEt-5] To a solution of ethyl 4-iodobenzoate (3.17 g, 11.5 mmol) in THF (35 mL), isopropylmagnesium bromide (15% THF solution, 1 M, 14 mL) was added and stirred at -20°C for 1 hour to prepare a Grignard reagent. Subsequently, copper(I) bromide dimethyl sulfide complex (2.346 g, 11.4 mmol) was added to prepare an organocopper reagent, followed by a solution of fullerene

[60] (0.52 g, 0.75 mmol) in oDCB (45 mL) and stirring at room temperature for 2 hours. After adding saturated aqueous ammonium chloride, the mixture was filtered through a short silica gel column and evaporated under reduced pressure using a rotary evaporator. The crude product was reprecipitated with dichloromethane / hexane to obtain PhCOOEt-5 (0.8 g, 78%) as a red powder.

[0052] [Synthesis of PhCOOH-5] PhCOOEt-5 (113.2 mg) was dissolved in toluene (30 mL), and a sodium hydroxide methanol solution (0.5 M, 2 mL) was added, followed by stirring at 60°C for 1 hour. The resulting precipitate was filtered, and the residue was washed with 1 M hydrochloric acid. Red powder of PhCOOH-5 (71%) was obtained.

[0053] [Synthesis of PhCOOH-5-OH] Sodium hydroxide methanol solution (0.5 M, 9 mL) and 10% tetrabutylammonium hydroxide methanol solution (1.5 mL) were added to an ethanol solution of PhCOOH-5 (204.4 mg), and the mixture was stirred at room temperature for 1 hour. 3 M hydrochloric acid was added in small portions to make the mixture acidic. The reaction solution was concentrated using a rotary evaporator, and then reprecipitated with methanol / 2-propanol. Black powder PhCOOH-5-OH (391.34 mg) (FLN=C ６０ , R １ = Ph, R ２ =COOH, R ３ = OH, F １ = H, n1 = 1, n2 = 5, n4 = 1).

[0054] [Examples 1 to 3] Figure 3 shows the synthesis pathways for the fullerene derivatives of Examples 1 to 3. Intermediates and final products are denoted by the abbreviations shown in the figure.

[0055] [Synthesis of PhOMe-10'] THF (30 mL) was added to copper(I) bromide dimethyl sulfide complex (6.8 g, 37.5 mmol), followed by a THF solution (16 equiv) of 3,4-dimethoxyphenylmagnesium bromide to prepare an organocopper reagent. 1,3-dimethyl-2-imidazolidinone (DMI) was added to this solution, followed by an ortho-dichlorobenzene (oDCB) solution (90 mL) of fullerene

[60] (2.0 g, 1.43 mmol), and the mixture was stirred at room temperature. After 1 hour, saturated aqueous ammonium chloride solution was added, and the mixture was filtered through a short silica gel column and then evaporated under reduced pressure using a rotary evaporator. PhOMe-10' was obtained as a red powder.

[0056] [Synthesis of Me(PhOMe10')] PhOMe10' (169 mg, 0.12 mmol) was dissolved in THF (10 mL), potassium hydride (1.5 equiv) was added, and the mixture was stirred at room temperature for 15 minutes. Next, methyl iodide (5 equiv) was added, and the mixture was further reacted at room temperature for 4 hours. The reaction mixture was filtered using a short silica gel column chromatography, and then evaporated under reduced pressure using a rotary evaporator. The resulting crude was purified by HPLC (COSMOSIL Buckyprep 20 mml.D. x 50 mm (Nacalai Tesque); Eluent: Toluene / Methanol = 7 / 3 (v / v)). Me(PhOMe10') was obtained as a red solid.

[0057] [Synthesis of Me(PhOH10')] Me(PhOMe10') (506 mg, 0.40 mmol) was dissolved in dichloromethane (20 mL) and cooled to 0°C in an ice bath. To this solution, boron tribromide dichloromethane solution (1 M, 10 equiv, 6 mL) was added portionwise. After 15 minutes, the reaction was quenched with methanol and then extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride and then evaporated under reduced pressure using a rotary evaporator. The crude was reprecipitated with acetone / hexane. A red powder, Me(PhOH10'), was obtained.

[0058] Thereafter, PhOMe-10'-OH (FLN=C ６０ , R １ = Ph, R ２ = OMe, R ３ = OH, F １ =H, n1 = 2, n2 = 5, n4 = 1).

[0059] [Examples 1 to 4] Figure 4 shows the synthesis pathways for the fullerene derivatives of Examples 1 to 4. Intermediates and final products are denoted by the abbreviations shown in the figure.

[0060] [Synthesis of PhOMe-15] THF (30 mL) was added to copper(I) bromide dimethyl sulfide complex (6.8 g, 37.5 mmol), followed by a THF solution (16 equiv.) of 3,4,5-trimethoxyphenylmagnesium bromide to prepare an organocopper reagent. 1,3-dimethyl-2-imidazolidinone (DMI) was added to this solution, followed by a solution of fullerene

[60] (2.0 g, 1.43 mmol) in ortho-dichlorobenzene (oDCB) (90 mL) and stirring at room temperature. After 1 hour, saturated aqueous ammonium chloride solution was added, followed by filtration using a short silica gel column and subsequent evaporation under reduced pressure using a rotary evaporator. PhOMe-15 was obtained as a red solid.

[0061] [Synthesis of PhOH15] PhOMe15 was dissolved in dichloromethane and cooled to 0°C in an ice bath. To this solution, boron tribromide dichloromethane solution (1 M, 30 equiv) was added portionwise. After 15 minutes, the reaction was quenched with methanol and then extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride and then evaporated under reduced pressure using a rotary evaporator. The crude product was reprecipitated with acetone / hexane. PhOH15 was obtained as a red powder.

[0062] Thereafter, PhOH-15-OH (FLN=C ６０ , R １ = Ph, R ２ =OH, R ３ = OH, F １ =H, n1 = 3, n2 = 5, n4 = 1).

[0063] [Examples 1 to 5] Figure 5 shows the synthesis pathways for the fullerene derivatives of Examples 1 to 5. Intermediates and final products are denoted by the abbreviations shown in the figure.

[0064] [H(PhPO ３ Et ２ ) ５ In a 100 mL Schlenk tube, ６０ (PhBr) ５Cl (99.8 mg, 65 μmol), nickel(II) chloride (8.4 mg, 64 μmol), and benzonitrile (6 mL) were added. Furthermore, triethyl phosphite (300 μL, 1.75 mmol) was added, and the mixture was heated to 180°C in an oil bath and stirred overnight. After cooling to room temperature, the solvent was removed using a rotary evaporator, and the mixture was roughly purified using a short silica gel column (methanol / ethyl acetate = 3:1). The resulting crude product was purified by HPLC (COSMOSIL Buckyprep 20 mm l.D. x 50 mm (Nacalai Tesque); Eluent: Toluene / Methanol = 7 / 3 (v / v)). A reddish-brown solid, H(PhPO ３ Et ２ ) ５ (FLN=C ６０ , R １ = Ph, R ２ =PO ３ Et ２ , F １ = H or Et, n1 = 5, n2 = 1, n3 = 0, n4 = 1).

[0065] Thereafter, PhPO was added in the same manner as in Example 1-1. ３ Et2-OH(FLN=C ６０ , R １ = Ph, R ２ =PO ３ Et ２ , R ３ = OH, F １ =H or Et, n1=1, n2=5, n4=1) are obtained.

[0066] [Examples 1 to 6] Figure 6 shows the synthesis pathways for the fullerene derivatives of Examples 1 to 6. The final products are represented by the abbreviations shown in the figure.

[0067] [C ３ H ６ SO ３ Synthesis of fullerene C ６０(112.5 mg, 0.15 mmol) and 1,3-propane sultone (422.7 mg, 3.4 mmol) were placed in the flask, and THF (4 mL) was added. Sodium dispersion (360 μL) was added dropwise, and the mixture was reacted with ultrasound at 50°C for 2 hours. After the reaction, the mixture was quenched with 2-propanol, and then hydrochloric acid was added. After evaporation under reduced pressure using a rotary evaporator, the mixture was decanted three times with toluene and reprecipitated with methanol. The residue was washed with methanol, dissolved in water, and filtered. The filtrate was evaporated under reduced pressure to give a brown powder (FLN=C ６０ , R １ =C ３ H ６ , R ２ =SO ３ H, F １ = H, n1 = n, n2 = 1, n3 = 0, n4 = 1).

[0068] [C ３ H ６ OSO ３ Synthesis of fullerene C ６０ (107.2 mg, 0.15 mmol), 1,3-propanediol cyclic sulfate (484.5 mg, 3.5 mmol), and THF (4 mL) were added. To this suspension, sodium dispersion (360 μL) was added dropwise, and the mixture was reacted with ultrasound at 50°C for 2 hours. After the reaction, the mixture was quenched with 2-propanol, and then hydrochloric acid was added. After evaporation under reduced pressure using a rotary evaporator, the mixture was decanted three times with toluene and reprecipitated with methanol. The residue was washed with methanol, dissolved in water, and filtered. The filtrate was evaporated under reduced pressure to give a brown powder (FLN=C ６０ , R １ =C ３ H ６ , R ２ =OSO ３ H, F １ = H, n1 = n, n2 = 1, n3 = 0, n4 = 1).

[0069] [C ２ H ４ Synthesis of fullerene C ６０(26.4 mg, 37.6 mol), THF (2 mL), and ethylene oxide (1 M THF solution, 1 mL) were added. To this suspension, sodium dispersion (100 μL) was added dropwise, and the mixture was reacted with ultrasound at 50°C for 2 hours. After the reaction, the mixture was quenched with 2-propanol, and then hydrochloric acid was added. After distillation under reduced pressure using a rotary evaporator, the mixture was decanted three times with toluene and reprecipitated with methanol. The residue was washed with methanol, dissolved in water, and filtered. The filtrate was distilled under reduced pressure to obtain a brown powder (FLN=C ６０ , R １ =C ２ H ４ , R ２ = OH, F １ = H, n1 = n, n2 = 1, n3 = 0, n4 = 1).

[0070] [Evaluation of n2 and n4] Figure 7 shows the measurement results of the fluorescence spectra of fullerene derivatives. The fluorescence spectra of various fullerene derivatives were measured using a fluorescence spectrophotometer (PL). The top row shows the fluorescence spectrum of nanom spectra D100, a fullerene derivative manufactured by Frontier Carbon Co., Ltd. The fullerene derivative has n1 R atoms in the ring. １ The fluorescence spectrum of the fullerene derivative with an OH group attached is shifted toward shorter wavelengths than the fluorescence spectrum of nanom spectra D100, in which a hydroxyl group is directly bonded to the fullerene ring. This is thought to be due to the contraction of the fullerene's π-conjugated system. Therefore, the values ​​of n2 and n4 can be evaluated from the amount of shift in the fluorescence spectrum. The peaks of the fluorescence spectra of the fullerene derivatives in the second to fourth stages are shifted by approximately 70 nm from the peak of the fluorescence spectrum of the fullerene derivative in the top stage, and the combined values ​​of n2 and n4 are estimated to be approximately 10 to 12.

[0071] Fullerene derivative C ３ H ６ SO ３ The results of elemental analysis of H were C: 61.94%, H: 3.72%, and S: 7.09%. As mentioned above, considering that n2 and n4 were estimated to be about 10 to 12 from the fluorescence spectrum, the chemical formula of this fullerene derivative is C ６０ H ５(C ３ H ６ SO ３ H) ３ ・14H ２ O (C ６９ H ５４ O ２３ S ３ , C: 61.51%, H: 4.04%, S: 7.14%).

[0072] [Evaluation of n3] Figure 8 shows the measurement results of the fluorescence spectra of fullerene derivatives. The fluorescence spectrum of PhOH-10-OH is shifted to the shorter wavelength side than the fluorescence spectrum of PhOH-10. This is thought to be due to the shrinkage of the π-conjugated system of the fullerene. In addition, the fluorescence spectrum of PhOH-10-OH has two broad peaks. This is thought to be due to the distribution of PhOH-10-OH with different n3.

[0073] 9 and 10 show the mass spectra of PhOMe-10'-OH. ２＋ The mass spectrum of a sample into which OH was introduced by reaction with hydrogen peroxide in the absence of Fe was shown. PhOMe-10'-OH with n3 of 0 to 6 was produced, and the main products were those with n3 = 2, 3, and 4. ２＋ The mass spectrum of a sample into which OH radicals were introduced by reaction with hydrogen peroxide in the presence of OH radicals was shown. PhOMe-10'-OH with n3 ranging from 0 to 13 was produced, with the main product being n3 = 3 or 4. In both cases, the phenyl group was not dissociated from the fullerene, indicating that the carbon-carbon bond on the fullerene was not dissociated by the OH radicals.

[0074] [Solubility] Figure 11 shows the solubility of fullerene derivatives in solvents. The percentage of fullerene derivative dissolved when 50 mg of fullerene derivative was placed in 1 mL of solvent is shown. PhOH-10 and PhCOOH-5 showed high solubility in organic solvents, but were almost insoluble in water. In contrast, PhOH-10-OH, PhCOOH-5-OH, and C ３ H ６ OSO ３ H, C ３ H ６SO ３ H is practically insoluble in organic solvents but exhibits extremely high solubility in water. When 50 mg of the fullerene derivative of the present disclosure is placed in 1 mL of a polar solvent (particularly water), the fullerene derivative may be dissolved at 4% or more, 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, 85% or more, 90% or more, or 95% or more. The polar solvent may be water, alcohol (e.g., methanol, ethanol, 1-propanol, 2-propanol, 1-butanol), carboxylic acid (e.g., formic acid, acetic acid), methylene chloride, acetone, acetonitrile, tetrahydrofuran, N,N-dimethylformamide, dimethyl sulfoxide, or the like.

[0075] [Structure] Figure 12 shows the infrared spectra of PhOMe-10 and PhOMe-10-OH. －１ and 2960 cm －１ The peak corresponds to the C-H stretching mode, and the peak at 1710 cm －１ The peak at 3400 cm corresponds to the C=O stretching mode. The peak at 3400 cm corresponds to the O-H stretching mode observed in hydroxylated fullerenes. －１ A broad peak around 1000 nm was not observed in PhOMe-10 but was observed in PhOMe-10-OH, confirming that PhOMe-10-OH contains a hydroxyl group directly bonded to the fullerene.

[0076] FIG. 13 shows C ３ H ６ SO ３ The infrared spectrum of H is shown at approximately 3500 cm －１ The prominent broad peak observed at is due to -SO ３ It shows the -OH stretching mode in the H group. －１ , 2923 cm －１ , 2851 cm －１ The three distinct bands seen at 1196 cm are consistent with C–H stretching modes associated with alkyl chains. －１ and 1041 cm －１The medium intensity band located at -SO ３ This is thought to be due to the symmetric and asymmetric stretching modes of O=S=O in the H group.

[0077] FIG. 14 shows the C ３ H ６ SO ３ The powder X-ray diffraction pattern (CuKα: 1.54 Å) of H is shown. Three broad amorphous peaks were observed in the pattern, which are the origin of the fullerene derivative C ３ H ６ SO ３ This is due to the presence of structural isomers and addition isomers of H. The d-spacing of the most prominent peak at 2θ = 10.06° was 8.78 Å.

[0078] [Thermal Stability] FIG. 15 shows the thermal stability of C under a nitrogen atmosphere. ３ H ６ SO ３ The results of thermogravimetric analysis (TGA) and differential thermal analysis (DTA) of H are shown. The DTA peaks are at 258°C and 383°C, corresponding to endothermic and exothermic events, respectively. In TGA, the obtained curve can be divided into three main regions. The first region is in the temperature range from 100°C to 250°C, and shows a small amount of weight loss. Since there is no peak in the DTA curve in this temperature range, the weight loss in this region is due to C ３ H ６ SO ３ The second region is believed to be due to the evaporation of residual water present in H. A moderate weight loss was observed in the temperature range from 250°C to 380°C. The DTA exothermic peak observed at 258°C indicates that the mass loss was due to C. ３ H ６ SO ３ C of H ６０ This indicates that the mass loss is due to the combustion of the propyl sulfonic acid group on the cage. In the third region, a large mass loss was observed in the temperature range above 380 °C. An exothermic peak was detected at 383 °C in the DTA curve, and C ６０ This indicates that the cage has disassembled.

[0079] Example 2 Next, an example of the electrolyte membrane of the present disclosure will be described.

[0080] [Preparation of fullerene derivative / Nafion composite solution] A 20 wt% Nafion dispersion solution (6 g) was placed in vial A and subjected to vacuum distillation using a rotary evaporator (50°C, 4 h). The solution was redissolved in N,N-dimethylformamide (DMF) and stirred overnight at 80°C and 400 rpm. A specified amount of a DMF solution of a fullerene derivative (0.5 g) was added to vial A, and the mixture was stirred at room temperature and 400 rpm for 2 hours, followed by ultrasonic cleaning for 1 hour. When preparing an electrolyte membrane containing cerium ions, a specified amount of a DMF solution of a fullerene derivative (0.5 g) and a DMF solution of cerium (III) / citric acid were added to vial A, and the mixture was stirred at room temperature and 400 rpm for 2 hours, followed by ultrasonic cleaning for 1 hour.

[0081] [Preparation of fullerene derivative / Nafion membrane] A membrane of the prepared fullerene derivative / Nafion composite solution was prepared using a film applicator (BEVS1818) (film formation speed: 20 mm / s, set membrane thickness: 50 μm). The prepared membrane was placed on a hot plate heated to 50 ° C and left to stand overnight, and then further heated to 140 ° C and left to stand for 4 hours. Finally, the membrane was placed in a vacuum desiccator heated to 60 ° C and vacuum dried for 2 hours.

[0082] [Washing of fullerene derivative / Nafion membrane] The prepared fullerene derivative / Nafion membrane was immersed in a 0.1 M aqueous sulfuric acid solution, heated to 80°C, and stirred for 1 hour. Next, the membrane was immersed in ultrapure water and stirred at 80°C for 1 hour. The above procedure was repeated twice. Finally, the membrane was placed in a vacuum desiccator heated to 170°C and vacuum dried for 2 hours.

[0083] [Electrolyte Membrane Photographs and Film Thickness] Figure 16 shows photographs and film thicknesses of electrolyte membranes to which PhOH-10 was added at 0.1 wt% (Example 2-1), 0.5 wt% (Example 2-2), and 2.5 wt% (Example 2-3). Figure 17 shows photographs and film thicknesses of electrolyte membranes to which PhOH-10-OH was added at 0.5 wt% (Example 2-4), PhCOOH5-OH at 0.5 wt% (Example 2-5), and C ３ H ６ SO ３FIG. 18 shows a photograph and film thickness of an electrolyte membrane to which 0.5 wt% of PhOH-10-OH (Example 2-6) was added. FIG. 18 shows a photograph, micrograph, and film thickness of an electrolyte membrane to which PhOH-10-OH and cerium ions were added at a molar ratio of 1 / 0.5 (Example 2-7), and an electrolyte membrane to which PhOH-10-OH and cerium ions were added at a molar ratio of 1 / 2 (Example 2-8). FIG. 19 shows photographs and film thickness of an electrolyte membrane to which 0.5 wt% of PhCOOH-5-OH was added (Example 2-5), an electrolyte membrane to which PhCOOH-5-OH and cerium ions were added at a molar ratio of 1 / 0.5 (Example 2-9), and an electrolyte membrane to which PhCOOH-5-OH and cerium ions were added at a molar ratio of 1 / 2 (Example 2-10). If the fullerene derivative added to the electrolyte membrane aggregates, the electrolyte membrane will have a cloudy color, but the electrolyte membranes of Examples 2-1 to 2-10 were transparent, indicating that the fullerene derivative was uniformly dispersed.

[0084] [Water content and proton conductivity of electrolyte membrane] Figure 20 shows the water content and proton conductivity of the electrolyte membranes of Examples 2-1, 2-2, and 2-3. The water absorption of the membranes containing only Nafion was approximately 22 to 25%, but the water content of the electrolyte membranes of Examples 2-1, 2-2, and 2-3 was equal to or greater than that of the membranes containing only Nafion, demonstrating that they could maintain their function as electrolyte membranes. The proton conductivity of the membranes containing only Nafion was approximately 0.07 to 0.08 Scm －１ However, the conductivity of the electrolyte membrane of Example 2-2 was shown to be higher than that of the membrane containing only Nafion. This is thought to be because the hydrogen atoms of the hydroxyl groups bonded to the phenyl groups contribute to proton conduction.

[0085] 21 shows the water content and proton conductivity of the electrolyte membranes of Examples 2-2, 2-4, and 2-5. The water content of the electrolyte membranes of Examples 2-2, 2-4, and 2-5 was higher than that of a membrane containing only Nafion, demonstrating that the membranes could maintain their function as electrolyte membranes. The proton conductivity of the electrolyte membranes of Examples 2-2, 2-4, and 2-5 was equal to or higher than that of a membrane containing only Nafion, and the proton conductivity of the electrolyte membranes of Examples 2-2 and 2-4 was particularly high.

[0086] FIG. 22 shows C ３ H ６ SO３ An electrolyte membrane containing 0.5 wt% of a fullerene derivative in which H in H is replaced with Na, and fullerene derivative C ３ H ６ SO ３ The figures show the water content and proton conductivity of the electrolyte membranes of Examples 2-6, to which 0.5 wt% of H was added. It was shown that the water content and proton conductivity of these electrolyte membranes were higher than those of membranes containing only Nafion. The content of the fullerene derivative may be 0.005 wt% or more, 0.01 wt% or more, 0.05 wt% or more, 0.1 wt% or more, 0.2 wt% or more, 0.3 wt% or more, 0.4 wt% or more, 0.5 wt% or more, 0.6 wt% or more, 0.7 wt% or more, 0.8 wt% or more, 0.9 wt% or more, or 1 wt% or more, based on the total weight of the electrolyte membrane. The content of the fullerene derivative may be 0.5 wt % or less, 0.6 wt % or less, 0.7 wt % or less, 0.8 wt % or less, 0.9 wt % or less, 1 wt % or less, 2 wt % or less, 3 wt % or less, 4 wt % or less, 5 wt % or less, 6 wt % or less, 7 wt % or less, 8 wt % or less, 9 wt % or less, or 10 wt % or less, based on the total weight of the electrolyte membrane. In particular, the content of the fullerene derivative is preferably 0.5 wt % or more and 1.0 wt % or less, based on the total weight of the electrolyte membrane.

[0087] Figure 23 shows the water content and proton conductivity of electrolyte membranes to which fullerene derivatives and cerium ions were added. It was shown that the water content of these electrolyte membranes was higher than that of the Nafion membrane. It was also shown that the proton conductivity of these electrolyte membranes was equal to or higher than that of the Nafion membrane. In the figure, the molar ratio of fullerene derivative to cerium ions indicates the molar ratio of the fullerene derivative and cerium ions (cerium nitrate hexahydrate) mixed when preparing the electrolyte membrane. As described above, since the produced electrolyte membrane was washed with acid, the cerium ion content in the electrolyte membrane after acid washing was 0.0023 wt % for the electrolyte membrane in which PhOH-10 and cerium ions were mixed at a molar ratio of 1 / 0.5, 0.0010 wt % for the electrolyte membrane in which PhOH-10-OH and cerium ions were mixed at a molar ratio of 1 / 0.5, and 0.0011 wt % for the electrolyte membrane in which PhCOOH-5-OH and cerium ions were mixed at a molar ratio of 1 / 0.5, based on the total weight of the electrolyte membrane. The molar ratio of cerium ions to fullerene derivative in the electrolyte membrane may be 1:10,000 or more, 1:5,000 or more, 1:1,000 or more, 1:500 or more, 1:100 or more, 1:50 or more, 1:10 or more, 1:50 or more, 1:10 or more, 1:5 or more, 1:1 or more, 1:0.5 or more, or 1:0.1 or more. The molar ratio of cerium ions to the fullerene derivative in the electrolyte membrane may be 1:0.1 or less, 1:0.5 or less, 1:1 or less, 1:5 or less, 1:10 or less, 1:50 or less, 1:100 or less, 1:500 or less, 1:1000 or less, or 1:5000 or less.

[0088] [Electrolyte Membrane Durability Evaluation Test (Fenton Test)] The electrolyte membrane was immersed in 100 mL of a 3.4% aqueous hydrogen peroxide solution containing 1 ppm of iron (II) ions. The solution was heated to 80°C using an oil bath and stirred. The concentrations of fluoride ions and hydrogen peroxide eluted from the electrolyte membrane were quantitatively analyzed using ion chromatography.

[0089] Figure 24 shows the results of Fenton tests on a commercially available Nafion membrane, a membrane made using commercially available Nafion, an electrolyte membrane with PhOH-10 added, an electrolyte membrane with PhOH-10-OH added, and an electrolyte membrane with PhCOOH5-OH added. The electrolyte membrane with PhCOOH-5-OH added showed less fluoride ion elution than the Nafion membrane.

[0090] FIG. 25 shows the results of a commercially available Nafion membrane, a membrane fabricated using the commercially available Nafion, and C ３ H ６ OSO ３ An electrolyte membrane containing Na and C ３ H ６ OSO ３ The results of the Fenton test of the electrolyte membrane with added H are shown. ３ H ６ OSO ３ The electrolyte membrane containing Na also exhibited the same properties as the fullerene derivative C. ３ H ６ OSO ３ The H-doped electrolyte membrane also showed higher durability than the Nafion membrane.

[0091] Figure 26 shows the results of Fenton tests on electrolyte membranes containing PhOH-10 and cerium ions, and on electrolyte membranes containing PhCOOH-5-OH and cerium ions. The electrolyte membrane containing PhOH-10 and cerium ions at a molar ratio of 1 / 0.5 was shown to be particularly durable.

[0092] [Durability Evaluation Test (OCV Test) of Membrane Electrode Assembly] A membrane electrode assembly was fabricated using the electrolyte membrane of the example, and an OCV test was performed. The OCV test is a test to reproduce the phenomenon in which, when a fuel cell is temporarily stopped and maintained at an open circuit voltage (OCV), oxygen cross-leaks through the electrolyte membrane from the cathode side and reacts with hydrogen at the anode to generate hydrogen peroxide, which then decomposes and generates hydroxyl radicals, etc., which decompose the electrolyte membrane. The measurement conditions were a cell temperature of 80°C, gas conditions of 0.200 NL / min (100% RH) nitrogen on the cathode side and 0.200 NL / min (100% RH) hydrogen on the anode side, and a measurement potential of 0.20 V → 0.50 V (0.5 mV / sec).

[0093] 27 shows the results of OCV tests on membrane electrode assemblies including a Nafion membrane, a Nafion membrane to which commercially available hydroxylated fullerenes have been added, and a Nafion membrane to which PhOH-10 has been added. The membrane electrode assembly including the Nafion membrane to which PhOH-10 has been added showed a significantly longer period until leakage current was observed than the membrane electrode assemblies including the Nafion membrane and the Nafion membrane to which commercially available hydroxylated fullerenes have been added, demonstrating improved durability of the membrane electrode assembly.

[0094] 28 shows the amount of fluoride ion discharged in an OCV test for membrane electrode assemblies including a Nafion membrane, a Nafion membrane to which commercially available hydroxide fullerenes had been added, and a Nafion membrane to which PhOH-10 had been added. The membrane electrode assembly including the Nafion membrane to which PhOH-10 had been added discharged less fluoride ions than the membrane electrode assemblies including the Nafion membrane and the Nafion membrane to which commercially available hydroxide fullerenes had been added, demonstrating improved durability of the electrolyte membrane.

[0095] 29 shows the amount of fluoride ion discharged in an OCV test of a membrane electrode assembly including a Nafion membrane and a Nafion membrane to which the fullerene derivative of the example was added. In the case of a membrane containing only Nafion, it took about 130 hours for the amount of fluoride ion discharged to reach about 20 mg. In contrast, when PhOH10 was added, it took about 280 hours, and when PhOH10 and cerium ions were added, it took about 380 hours, and the discharge rate of fluoride ions was slower than that of the Nafion membrane. This indicates that the durability of the electrolyte membrane was improved.

[0096] 30 shows the amount of fluoride ions discharged in an OCV test of a membrane electrode assembly including a Nafion membrane and a Nafion membrane to which the fullerene derivative of the example was added. In the case of a membrane containing only Nafion, it took about 50 hours for the amount of fluoride ions discharged to reach about 5 mg. In contrast, in the case of a membrane containing only Nafion, it took about 50 hours for the amount of fluoride ions discharged to reach about 5 mg. ３ H ６ OSO ３The fluoride ion release rate was lower than that of the Nafion membrane, with the addition of H and cerium ions reaching approximately 100 hours, the addition of PhCOOH-5-OH reaching approximately 120 hours, and the addition of PhOH-10-OH and cerium ions reaching approximately 500 hours. Furthermore, with the addition of PhCOOH-5-OH and cerium ions, the release of fluoride ions was only about 2 mg even after 650 hours. This indicates that the durability of the electrolyte membrane was improved.

[0097] 31 shows the OCV in the OCV test of the membrane electrode assembly including the Nafion membrane to which the fullerene derivative of the example was added. In the case of the membrane containing only Nafion, the durability time was about 100 hours. ３ H ６ OSO ３ The durability of the electrolyte membrane was improved, showing that it was about 160 hours when H was added, about 270 hours when PhOH10 was added, and about 400 hours when PhOH10 and cerium ions were added.

[0098] 32 shows the OCV in the OCV test of the membrane electrode assembly including the Nafion membrane to which the fullerene derivative of the example was added. In the case of the membrane containing only Nafion, the durability time was about 100 hours. ３ H ６ OSO ３ The durability was approximately 200 hours when H and cerium ions were added, approximately 570 hours when PhOH-10-OH and cerium ions were added, approximately 175 hours when PhCOOH-5-OH was added, and approximately 900 hours or more when PhCOOH-5-OH and cerium ions were added, indicating that the durability of the electrolyte membrane was improved.

[0099] [Strength] Tensile tests were performed three times on films containing the fullerene derivatives of the examples, and the average values ​​of tensile strength, elongation, and Young's modulus were measured. Figure 33 shows the tensile strength of a film containing the fullerene derivatives of the examples. Figure 34 shows the elongation of a film containing the fullerene derivatives of the examples. Figure 35 shows the Young's modulus of a film containing the fullerene derivatives of the examples. The strength of the film was improved by adding the fullerene derivatives of the examples. When cerium ions were added, the tensile strength and elongation decreased, but sufficient tensile strength and elongation were maintained.

[0100] [Examples 1-7 to 1-9] Figure 36 shows the synthesis routes for the fullerene derivatives of Examples 1-7, 1-8, and 1-9. Intermediates and final products are represented by the abbreviations shown in the figure.

[0101] [C ６０ (C ６ H ４ Br) ５ CH ３ Synthesis of (4-bromophenyl)chloromagnesium (BrC ６ H ４ Preparation of 1-bromo-4-iodobenzene (MgCl): A 100-mL two-necked round-bottom flask was charged with 1-bromo-4-iodobenzene (11.0 g, 38.9 mmol, 1 equiv) and THF (80 mL). After cooling the mixture to −25° C., ｉ A solution of PrMgCl in THF (20 mL, 2 M, 40 mmol, 14 equiv) was added and the resulting mixture was stirred at −25° C. for 2 h.

[0102] CuBr.SMe was placed in a 300-mL two-neck round-bottom flask. ２ (8.0g, 38.9mmol, 14equiv), BrC ６ H ４ The MgCl solution was added and the resulting mixture was stirred at room temperature for 10 minutes. ６０A solution of (2.0 g, 2.78 mmol, 1 equiv) in ODCB (90 mL) was added, and the mixture was stirred at room temperature for 3 hours. Next, iodomethane (17 mL) was added, and the mixture was stirred at 50°C for an additional 3 hours. After that, the mixture was passed through a short silica gel column chromatography, and the resulting solution was evaporated under reduced pressure. The resulting oily crude product was purified by silica gel column chromatography (eluent: CS2 → n-hexane → chloroform). After concentrating the fractions, the solution was reprecipitated with methanol to obtain compound C. ６０ (C ６ H ４ Br) ５ CH ３ (4.2 g, 0.57 mmol, 99%) was obtained as an orange solid.

[0103] [C ６０ (C ６ H ４ P.O. ３ Et ２ ) ５ CH ３ Synthesis of Compound C (Examples 1-7) ６０ (C ６ H ４ Br) ５ CH ３ (511 mg, 0.34 mmol, 1 equiv), anhydrous nickel chloride (15.3 mg, 0.11 mmol, 0.35 equiv), benzonitrile (48 mL), and triethyl phosphite (430 μL, 2.54 mmol, 7.5 equiv) were charged. The resulting mixture was stirred at 190° C. for 3 hours. After cooling at room temperature, the reaction mixture was concentrated under reduced pressure. The resulting oily crude product was redissolved in a small amount of ethyl acetate and precipitated with n-hexane. The precipitate was collected by filtration, and the product was purified using HPLC (Buckyprep column, eluent: toluene / methanol=7 / 3) to give compound C. ６０ (C ６ H ４ P.O. ３ Et ２ ) ５ CH ３ (396 mg, 0.22 mmol, 65%) (FLN=C ６０ , R １ = Ph, R ２ =PO３ Et ２ , F １ =CH ３ , n1=1, n2=5, n4=1) was obtained as an orange-red solid.

[0104] [C ６０ (C ６ H ４ P.O. ３ H ２ ) ５ CH ３ Synthesis of Compound C (Examples 1-8) ６０ (C ６ H ４ P.O. ３ Et ２ ) ５ CH ３ (1.89 g, 1.05 mmol, 1 equiv) and dichloromethane (5 mL) were charged. Trimethylsilyl bromide (1.2 mL, 31.5 mmol, 30 equiv) was slowly added, and the resulting mixture was refluxed for 3 days. After cooling to room temperature, methanol was added to the reaction mixture, which was then concentrated under reduced pressure. The resulting crude product was redissolved in a small amount of water and precipitated with acetone. The precipitate was collected by filtration to give compound C. ６０ (C ６ H ４ P.O. ３ H ２ ) ５ CH ３ (1.58g, 1.00mmol, 99%) (FLN=C ６０ , R １ = Ph, R ２ =PO ３ H ２ , F １ =CH ３ , n1=1, n2=5, n4=1) was obtained as a red solid.

[0105] [C ６０ (C ６ H ４ P.O. ３ H ２ ) ５ CH ３ Synthesis of —OH (Examples 1-9) Compound C was placed in a flask. ６０ (C ６ H ４ P.O. ３H ２ ) ５ CH ３ (107 mg, 0.07 mmol), 5 mL of water, and sodium hydroxide (1.3 g, 32.5 mmol) were added and stirred at room temperature. After 5 hours, 30% aqueous hydrogen peroxide solution (6 mL) was added, heated to 60°C, and further stirred overnight. Saturated aqueous sodium thiosulfate solution was then added in small portions to inactivate the hydrogen peroxide. The reaction mixture was evaporated under reduced pressure using a rotary evaporator, and the remaining oily composition was reprecipitated with methanol. 3 M hydrochloric acid was added to the composition to adjust the pH to acidic. The solution was placed in a dialysis tube (benzoylation, Avg. flat width 32 mm, Sigma Aldrich) and immersed in a beaker containing pure water. The water in the beaker was replaced daily and the mixture was left to stand for two weeks. The mixture was then evaporated under reduced pressure using a rotary evaporator and desalted over two weeks. Red solid C ６０ (C ６ H ４ P.O. ３ H ２ ) ５ CH ３ -OH(FLN=C ６０ , R １ = Ph, R ２ =PO ３ H ２ , R ３ = OH, F １ =CH ３ , n1 = 1, n2 = 5, n4 = 1).

[0106] [Examples 1-10 to 1-11] Figure 37 shows the synthesis routes for the fullerene derivatives of Examples 1-10 and 1-11. Intermediates and final products are represented by the abbreviations shown in the figure.

[0107] [C ６０ (C ６ H ４ C ６ H ４ Br) ５ CH ３ Synthesis of Grignard solution (BrC ６ H ４ C ６ H ４Preparation of iPrMgCl): A 100-mL two-necked round-bottom flask was charged with 4-bromo-4'-iodobiphenyl (2.0 g, 5.56 mmol, 1 equiv) and THF (15 mL). After the mixture was cooled to −25°C, a THF solution of iPrMgCl (2.8 mL, 2 M, 5.6 mmol, 16 equiv) was added, and the resulting mixture was stirred at −25°C for 2 hours.

[0108] CuBr.SMe was placed in a 300-mL two-neck round-bottom flask. ２ (1.14g, 5.58mmol, 16equiv), BrC ６ H ４ The MgCl solution was added and the resulting mixture was stirred at room temperature for 10 minutes. ６０ A solution of (250 mg, 0.347 mmol, 1 equiv) in ODCB (15 mL) was added, and the mixture was stirred at room temperature for 2 hours. Next, iodomethane (2 mL) was added, and the mixture was stirred at 50°C for an additional 3 hours. After that, the mixture was passed through a short silica gel column chromatography, and the resulting solution was evaporated under reduced pressure. The obtained oily crude product was purified by silica gel column chromatography (eluent: CS ２ The fractions were concentrated, and the solution was reprecipitated with methanol to obtain Compound C. ６０ (C ６ H ４ C ６ H ４ Br) ５ CH ３ (682 mg, 0.35 mmol, const.) was obtained as an orange solid.

[0109] [C ６０ (C ６ H ４ C ６ H ４ P.O. ３ Et ２ ) ５ CH ３ Synthesis of Compound C (Examples 1-10) ６０ (C ６ H ４ C ６ H ４ Br) ５ CH ３(640 mg, 0.33 mmol, 1 equiv), anhydrous nickel chloride (15.3 mg, 0.11 mmol, 0.35 equiv), benzonitrile (48 mL), and triethyl phosphite (430 μL, 2.54 mmol, 7.5 equiv) were charged. The resulting mixture was stirred at 190° C. for 3 hours. After cooling at room temperature, the reaction mixture was concentrated under reduced pressure. The resulting oily crude product was redissolved in a small amount of ethyl acetate and precipitated with n-hexane. The precipitate was collected by filtration, and the product was purified using HPLC (Buckyprep column, eluent: toluene / methanol=7 / 3) to give compound C. ６０ (C ６ H ４ C ６ H ４ P.O. ３ Et ２ ) ５ CH ３ (206.4 mg, 0.096 mmol, 28%) was obtained as an orange-red solid.

[0110] [C ６０ (C ６ H ４ C ６ H ４ P.O. ３ H ２ ) ５ CH ３ Synthesis of Compound C (Examples 1-11) ６０ (C ６ H ４ C ６ H ４ P.O. ３ Et ２ ) ５ CH ３ (200.1 mg, 0.91 mmol, 1 equiv) and dichloromethane (0.5 mL) were charged. Trimethylsilyl bromide (360 μL, 27.3 mmol, 30 equiv) was slowly added, and the resulting mixture was refluxed for 3 days. After cooling to room temperature, methanol was added to the reaction mixture, which was then concentrated under reduced pressure. The resulting crude product was redissolved in a small amount of water and precipitated with acetone. The precipitate was collected by filtration to give compound C. ６０ (C ６ H ４ C ６ H ４P.O. ３ H ２ ) ５ CH ３ was obtained as a red solid.

[0111] [Examples 1 to 12] Figure 38 shows the synthesis pathways for the fullerene derivatives of Examples 1 to 12. Intermediates and final products are indicated by the abbreviations shown in the figure.

[0112] [C ６０ (C ６ H ４ SiMe ３ ) ５ CH ３ Synthesis of Grignard solution (Me ３ SiC ６ H ４ Preparation of MgCl): A 100-mL two-neck round-bottom flask was charged with magnesium (800 mg, 34.73 mmol, 3 equiv), lithium chloride (470 mg, 11.18 mmol, 1 equiv), and THF (30 mL). To this mixture was added 1-bromo-4-(trimethylsilyl)benzene (2.1 mL, 11.18 mmol, 1 equiv), and the resulting mixture was stirred at 40°C for 4 hours.

[0113] CuBr.SMe was placed in a 300-mL two-neck round-bottom flask. ２ (2.3g, 11.18mmol, 16equiv), Me ３ SiC ６ H ４ The MgCl solution was added and the resulting mixture was stirred at room temperature for 10 minutes. ６０ A solution of (500 mg, 0.694 mmol, 1 equiv) in ODCB (25 mL) was added, and the mixture was stirred at room temperature overnight. Next, iodomethane (4.3 mL) was added, and the mixture was stirred at 50°C for an additional 7 hours. Thereafter, the mixture was passed through a short silica gel column chromatography, and the resulting solution was evaporated under reduced pressure. The resulting oily crude product was purified by silica gel column chromatography (eluent: CS ２ The fractions were concentrated and then purified by HPLC (Buckyprep column, eluent: toluene / methanol = 7 / 3). ６０ (C ６ H ４SiMe ３ ) ５ CH ３ was obtained as an orange solid.

[0114] [C ６０ (C ６ H ４ SO ３ H) ５ CH ３ In a 100-mL Schlenk flask, compound C ６０ (C ６ H ４ SiMe ３ ) ５ CH ３ (50 mg, 33.7 μmol, 1 equiv.) was added and dissolved in 1,2-dichloroethane (4 mL). To this solution, trimethylsilyl chlorosulfonate (100 μL, 65 μmol, 20 equiv.) was slowly added, and the mixture was heated to 90°C and stirred overnight. After cooling to room temperature, water was added to the reaction mixture, and the mixture was further heated to 90°C and stirred overnight. The reaction mixture was concentrated under reduced pressure, and the crude product was reprecipitated with diethyl ether. The product was redissolved in a small amount of ethyl acetate and precipitated with n-hexane. The precipitate was collected by filtration, and the product was purified by HPLC to obtain compound C. ６０ (C ６ H ４ SO ３ H) ５ CH ３ was obtained as an orange-red solid. The compound was identified by HRMS (ESI, negative). Calcd. for C 91 H 28 O 15 S5 [M-2H] 2- 759.4959; found, 759.4974, Calcd. for C 91 H 28 O 15 S5 [M-3H] 3- 505.9949; found, 505.9948, Calcd. for C 91 H 28 O 15 S5 [M-4H] 4- 379.2443; found, 379.2420, Calcd. for C 91 H28 O 15 S5 [M-5H] 5- 303.1940; found, 303.1940.

[0115] [Solubility] Figure 39 shows the solubility of fullerene derivatives in solvents. The percentage of the fullerene derivative dissolved when 50 mg of the fullerene derivative was placed in 1 mL of solvent is shown. The fullerene derivatives of Examples 1-8, 1-9, 1-11, and 1-12 were almost insoluble in organic solvents but were 100% soluble in water.

[0116] [Structure] Figure 40 shows C ６０ (C ６ H ４ Br) ５ CH ３ and C ６０ (C ６ H ４ P.O. ３ Et ２ ) ５ CH ３ The molecular structure determined by single crystal X-ray structural analysis is shown below. This confirmed that the target compound was obtained.

[0117] Figure 41 shows C ６０ (C ６ H ４ P.O. ３ Et ２ ) ５ CH ３ , C ６０ (C ６ H ４ P.O. ３ H ２ ) ５ CH ３ , and C ６０ (C ６ H ４ P.O. ３ H ２ ) ５ CH ３ The infrared spectrum of —OH is shown. ６０ (C ６ H ４ P.O. ３ Et ２ ) ５ CH ３ In the spectrum of －１, 2929 cm －１ , and 2970 cm －１ The peak corresponds to the C-H stretching mode of the ethoxy group. ６０ (C ６ H ４ P.O. ３ H ２ ) ５ CH ３ Since these peaks are not confirmed in the spectrum of ６０ (C ６ H ４ P.O. ３ H ２ ) ５ CH ３ was confirmed. ６０ (C ６ H ４ P.O. ３ H ２ ) ５ CH ３ In the spectrum of -OH, 3000 cm －１ A broad peak can be seen around this point, indicating the presence of hydroxyl groups introduced into the fullerene cage.

[0118] [Examples 2-11 to 2-14] [Electrolyte membrane photograph and membrane thickness] FIG. ６０ (C ６ H ４ P.O. ３ Et ２ ) ５ CH ３ 0.5 wt% of the electrolyte membrane (Example 2-11), C in a molar ratio of 1 / 0.5 ６０ (C ６ H ４ P.O. ３ Et ２ ) ５ CH ３ and cerium ion-added electrolyte membrane (Example 2-12), C ６０ (C ６ H ４ P.O. ３ H ２ ) ５ CH ３ 0.5 wt% of the electrolyte membrane (Example 2-13), C in a molar ratio of 1 / 0.5 ６０ (C ６ H４ P.O. ３ Et ２ ) ５ CH ３ Photographs of the electrolyte membrane containing cerium ions and the electrolyte membrane containing cerium ions (Example 2-14) are shown, along with their thicknesses.

[0119] [Water content and proton conductivity of electrolyte membrane] Figure 43 shows the water content and proton conductivity of the electrolyte membranes of Examples 2-11, 2-12, 2-13, and 2-14. The water absorption of the membranes containing only Nafion was approximately 22 to 25%, but the water content of Examples 2-11, 2-12, 2-13, and 2-14 was equal to or higher than that of the membranes containing only Nafion, demonstrating that the membranes could maintain their function as electrolyte membranes. The proton conductivity of the membranes containing only Nafion was approximately 0.07 to 0.08 Scm －１ However, the conductivity of the electrolyte membranes of Examples 2-11 and 2-12 was higher than that of the membrane containing only Nafion. This is thought to be because the oxygen atoms of the phosphonic acid groups bonded to the phenyl groups contribute to proton conduction.

[0120] [Durability evaluation test (OCV test) of membrane electrode assembly] Figures 44 and 45 show the results of an OCV test of a membrane electrode assembly including a Nafion membrane and a Nafion membrane to which the fullerene derivative of the example has been added. Figures 46 and 47 show the amount of fluoride ion discharged in the OCV test of a membrane electrode assembly including a Nafion membrane and a Nafion membrane to which the fullerene derivative of the example has been added. The membrane electrode assembly including the Nafion membrane to which the fullerene derivative having a phosphonate ester group and a phosphonic acid group has been added discharged fluoride ions much less than the Nafion membrane, indicating that the durability of the electrolyte membrane has been improved.

[0121] The present disclosure has been described above based on examples. These examples are merely illustrative, and it will be understood by those skilled in the art that various modifications are possible in the combination of the components and processing steps, and that such modifications are also within the scope of the present disclosure.

[0122] The present invention is applicable to an electrolyte membrane, a method for manufacturing an electrolyte membrane, and a membrane electrode assembly.

Claims

1. An electrolyte and a compound represented by the formula (1) (wherein FLN is fullerene or a derivative thereof, and R １ is an additional group containing one or more carbon atoms, and R ２ and R ３ are each independently a substituent containing one or more polar groups, and n1≧1, n2≧1, and n3≧0.

2. n2 substituents R １ (R ２ ) ｎ１ is bonded to a carbon atom belonging to one of the two hemispheres obtained by dividing the fullerene in half by a plane passing through the center of the fullerene, and n3 substituents R ３ is n2 substituents R １ (R ２ ) ｎ１ The electrolyte membrane according to claim 1 , wherein the carbon atom to which the carbon atom belongs is bonded to a carbon atom belonging to a hemisphere different from the hemisphere to which the carbon atom to which the carbon atom belongs is bonded.

3. Formula (4) The electrolyte membrane according to claim 1 , comprising a fullerene derivative having the structure:

4. R ２ is PO(OH) ２ , OPO(OH) ２ , S.O. ３ 4. The electrolyte membrane according to claim 3, wherein the hydrogen atom is H, or the H contained therein is substituted with a metal atom or an alkyl group.

5. Formula (2) The electrolyte membrane according to claim 3 , comprising a fullerene derivative having the structure:

6. Formula (3) The electrolyte membrane according to claim 1 , comprising a fullerene derivative having the structure:

7. The electrolyte membrane according to any one of claims 1 to 6, wherein the content of the fullerene derivative is 0.005% by weight to 5% by weight based on the total weight of the electrolyte membrane.

8. The electrolyte membrane according to any one of claims 1 to 6, further comprising cerium ions.

9. The electrolyte membrane according to claim 8, wherein the molar ratio of cerium ions to the fullerene derivative is 1:10,000 to 1:0.

1.

10. The electrolyte membrane according to any one of claims 1 to 6, wherein the fullerene derivative is uniformly dispersed in the electrolyte membrane.

11. An electrolyte and a compound represented by the formula (1) (wherein FLN is fullerene or a derivative thereof, and R １ is an additional group containing one or more carbon atoms, and R ２ and R ３ are each independently a substituent containing one or more polar groups, and n1 ≧ 1, n2 ≧ 1, and n3 ≧ 0.) A method for manufacturing an electrolyte membrane, comprising: forming an electrolyte membrane containing the electrolyte and the fullerene derivative using a solution obtained by dissolving the electrolyte and a fullerene derivative having a structure of the formula (I) in a polar solvent.

12. A manufacturing step of manufacturing a fullerene derivative having a structure of formula (1), wherein the manufacturing step comprises adding n2 additional groups R to a fullerene or a derivative thereof. １ (R ２ ) ｎ１ a first step of introducing n2 additional groups R １ (R ２ ) ｎ１ Introduced into fullerene or its derivative is n3 substituents R ３ and a second step of introducing:

13. The first step is to react fullerene or its derivative with a Grignard reagent (R ２ ) ｎ１ R １ MgX (where X is a halogen) and copper salt CuX.SMe ２ The method of claim 12 , comprising the step of:

14. The second step is to add n2 additional groups R １ (R ２ ) ｎ１ The method according to claim 12 or 13, comprising a step of reacting an alkali with the fullerene or derivative thereof into which the formula (I) has been introduced.

15. The second step is to add n2 additional groups R １ (R ２ ) ｎ１ The method according to claim 12 or 13, comprising a step of reacting iron and hydrogen peroxide with fullerene or a derivative thereof into which the formula (I) has been introduced.

16. A membrane electrode assembly comprising: an electrolyte membrane according to any one of claims 1 to 6; a cathode catalyst layer disposed on one side of the electrolyte membrane; and an anode catalyst layer disposed on the other side of the electrolyte membrane.

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