KR101342598B1 - Proton conductive polymer electrolyte and fuel cell employin the same - Google Patents

Abstract

The present invention provides a proton conductive polymer electrolyte capable of stably exhibiting power generation performance that works well under operating conditions of no humidification or relative humidity of 50% or less at an operating temperature of 100 ° C to 200 ° C, and a fuel cell employing the same. A proton conductive polymer electrolyte comprising an aromatic hydrocarbon polymer having an acidic functional group and a composition containing at least a compound having an electron donating functional group is employed.

Description

Proton conductive polymer electrolyte and fuel cell employin the same

The present invention relates to a proton conductive polymer electrolyte and a fuel cell employing the same, in particular, a solid polymer fuel cell stably exhibiting good power generation performance for a long time even under an operating temperature of 100 ° C. to 200 ° C. even under 50% or no relative humidity. It is about.

As electrolytes for fuel cells, fluorinated polyethylene sulfonic acid membranes which are also used for salt electrolysis, seawater desalination, water treatment, etc. are widely used for reasons of excellent proton conductivity and chemical stability. For example, Nafion membrane, Flemion membrane, Aciplex membrane, Dow membrane (all are brand names), etc. are marketed.

However, since these electrolyte membranes contain fluorine, they are disadvantageous in terms of environment and expensive.

As an electrolyte membrane containing no fluorine, polystyrene sulfonic acid is proposed as an ion exchange resin for water treatment, an ion exchange membrane, and the like, and a sulfonated aromatic polymer for fuel cells and the like (Japanese Patent Laid-Open No. 11-502245, T. Kobayashi, M.A.). Rikukawa, K. Sanui, N. Ogata, Solid State Ionics, Vol. 106, 1998, p.219).

However, they have insufficient heat resistance and chemical stability for practical use as a fuel cell.

In addition, as a non-aqueous proton conductive electrolyte, non-volatile low-temperature base salts such as molten salt, phosphoric acid, and imidazole such as proton acceptors or carriers are used to complex these room-temperature molten salts, phosphoric acid, and low-molecular bases with heat-resistant polymers. Known. However, these compounds are often soluble in water, and there is a problem of outflowing out of the system by water generated in the system during generation of fuel cells.

The present invention has been made to solve the above problems, proton conductivity capable of stably exhibiting long-term stable power generation performance at operating conditions of 100 ℃ to 200 ℃, operating conditions of 50% or less humidification or relative humidity It is an object to provide a polymer electrolyte and a fuel cell.

In the present invention, a compound having a specific electron donating group is found as a compound that becomes a proton acceptor and is insoluble in water, such as a conventional room temperature molten salt or phosphoric acid. By using together, it was discovered that an optimum membrane can be provided as an electrolyte membrane for fuel cells operated at a high humidity without humidification. That is, this invention has become possible to solve the said subject by employ | adopting the following structures.

The proton conductive polymer electrolyte of the present invention comprises a composition containing at least an aromatic hydrocarbon-based polymer having an acidic functional group and a compound having an electron donating functional group.

In addition, in the proton conductive polymer electrolyte of the present invention, the compound having the electron donating functional group is preferably contained in the range of 0.01 to 50 parts by weight based on 100 parts by weight of the aromatic hydrocarbon polymer having the acidic functional group.

In the proton conductive polymer electrolyte of the present invention, the melting point of the compound having the electron donating functional group is preferably 100 ° C. or higher, particularly 110 to 130 ° C., and the boiling point is 200 ° C. or lower, particularly 160 to 190 ° C. Moreover, in the proton conductive polymer electrolyte of this invention, it is preferable that the acidic functional group of the aromatic hydrocarbon type polymer which has the said acidic functional group is a sulfonic acid group or a sulfamide acid group.

In the proton conductive polymer electrolyte of the present invention, the aromatic hydrocarbon polymer having the acidic functional group is preferably a polyamic acid derivative represented by the following general formula (1).

[Formula 1]

Wherein Ar is an aromatic ring or a group containing an aromatic ring, R is a C1-C20 alkylene group, 0 ≦ a ≦ 2, 0 ≦ b ≦ 2, provided that a + b = 2 and n is the average degree of polymerization As an integer of 100 to 10000.

The fuel cell of the present invention comprises a pair of electrodes and an electrolyte membrane disposed between each electrode, and the electrolyte membrane is made of the above-described proton conductive polymer electrolyte.

Moreover, in the fuel cell of this invention, it is preferable that the said proton conductive polymer electrolyte is contained in the said electrode.

According to the present invention, a composition comprising an aromatic hydrocarbon-based polymer having an acidic functional group and a compound having an electron donating functional group is used as an electrolyte of a fuel cell, so that the operating temperature is 100 ° C. to 200 ° C. without humidification or relative humidity 50. It is possible to provide a polymer electrolyte fuel cell having a high current density, a high output, and a high lifetime even under%.

Hereinafter, the proton conductive polymer electrolyte and the fuel cell of the present invention will be described in detail.

[Proton Conductive Polymer Electrolyte]

The proton conductive polymer electrolyte according to the present invention is composed of an aromatic hydrocarbon polymer having an acidic functional group and a composition containing at least a compound having an electron donating functional group.

(Aromatic Hydrocarbon Type Polymer)

As the acidic functional group in the aromatic hydrocarbon polymer, a functional group capable of releasing protons such as a carboxyl group, a phosphonic acid group, a sulfonic acid group, and a sulfamide acid group is preferable, and a sulfonic acid group, a carboxyl group or a sulfamide acid group is more preferable, and a sulfonic acid group Or a sulfamic acid group is particularly preferred.

As an aromatic hydrocarbon type polymer which has a sulfamide acid group, the polyamic-acid derivative represented by following General formula (1) is preferable.

[Formula 1]

In the following formula (1), Ar is an aromatic ring or a group containing an aromatic ring, R is a C1-C20 alkylene group, more specifically R is an alkyl group having 3 to 12 carbon atoms, wherein And b is 0 ≦ a ≦ 2, 0 ≦ b ≦ 2, provided that a + b = 2 and n is an integer of 100 to 10000 as the average degree of polymerization.

Examples of the group containing an aromatic ring or an aromatic ring include a phenyl group and a naphthyl group, but are not limited thereto.

As for the average degree of polymerization of the said polyamic acid derivative, the range of 100-10000 is preferable as mentioned above. If the average degree of polymerization is less than 100, the film cannot be formed, and if the average degree of polymerization is more than 10000, it will be difficult to dissolve in a solvent, making cast film very suitable as a means of complexing with a compound having an electron donating functional group.

As said polyamic acid derivative, it is very suitable to set it as the compound in which all or one part of the side chain carboxyl groups of polyamic acid are sulfidated. As such a polyamic acid derivative, all or part of the side chain carboxyl group of a polyamic acid is acid-chloride-ized, what is obtained by making it react with the amido sulfate triethyl amine salt, and carrying out cation exchange can be used suitably.

Moreover, it is preferable that the introduction ratio (a / b) of the functional group of the polyamic-acid derivative represented by the said Formula (1) is 80%-100% of range. If the introduction ratio (a / b) of the functional group is less than 80%, sufficient proton conductivity cannot be obtained.

In the case where the sulfamide acid group is introduced at a high introduction rate as the side chain of the polyamide, the flexibility when forming the film as an electrolyte membrane may be reduced, resulting in an unstable membrane. In the present invention, alkylene is added to the main chain of the polyamide. Since it is set as the polyamic-acid derivative of the structure containing a group, even when the sulfamide acid group is introduce | transduced as a side chain of polyamide at a high introduction rate, it is excellent in flexibility when film-forming as an electrolyte membrane, and can suppress that a membrane falls.

The synthesis of the polyamic acid derivative can be carried out by the following method, for example.

When synthesize | combining the said polyamic-acid derivative as a sulfamide polyamide sulfamide, it is preferable to carry out according to the method of sulfamide of the side chain carboxylic acid of a polyamic acid from the point of ease of synthesis. In particular, it is preferable to make it the method obtained by making acid-chloride of the side chain carboxyl group of polyamic acid, reacting with amido sulfate triethyl amine salt, and carrying out cation exchange.

An example of the synthesis scheme of the polyamide sulfamide acid is shown in Scheme 1 below.

[Reaction Scheme 1]

As shown in the said synthesis scheme, the polyamic acid (5) used as a starting polymer can be produced by polycondensation of aromatic tetraacetic dianhydride (3) and aromatic diamine (4), for example. In addition, Ar, R, n in compounds (3)-(5) are the same as what was defined in the said compound (1) (objective product, a compound of General formula (1)).

By stirring and mixing the polyamic acid (5) and thionyl chloride (SOCl ₂ ) in an amide solvent at room temperature or low temperature for several hours to 24 hours, all or at least part of the side chain carboxylic acids of the polyamic acid (5) Converted to an acid chloride group (acid chloride). In the example shown in compound (6), only one side of the side chain carboxylic acid of the polyamic acid (5) is converted into an acid chloride group, and the other side is a carboxylic acid, and this other side chain carboxylic acid is also converted into an acid chloride group. can do. Examples of the amide solvent used at this time include N, N'-dimethylacetamide, N, N'-dimethylformamide, and the like. After completion of the reaction, the reaction solution was poured into methanol, and the precipitated polymer was filtered and washed to separate the produced polymer 6.

The obtained polymer (6) and amido sulfate triethyl amine salt (NH ₂ SO ₃ H.N (C ₂ H ₅ ) ₃ ) were mixed in an amide solvent under stirring at room temperature or low temperature for several hours to 24 hours, thereby providing a general formula ( The polyamide sulfamic acid triethyl amine salt of 7) is synthesized. In the example shown in the compound (7), only one acid chloride in the side chain of the polyamic acid (5) is converted to the sulfamide salt in the reaction. As described above, the other side chain carboxylic acid is also acid chloride. When converted, the other side chain can also be converted to sulfamide salts. As an amide solvent used at this time, the same thing as the said acid chloride reaction is used. After completion of the reaction, the reaction solution is poured into methanol or the like, and the resulting polymer 7 is separated by filtration and washing of the precipitate.

Finally, the solution of the obtained polyamide sulfamide acid triethyl amine salt (7, for example, N, N'-dimethylacetamide solution, etc.) is passed through a cation exchange resin to cation exchange (sulfuramide acid sulfamide). Acid) and protonated. The treatment solution is poured into methanol, dichloromethane or chloroform, and the precipitate is filtered and washed to obtain a polyamic acid derivative represented by the formula (1) as a target.

In addition, the polyamic acid derivative represented by the general formula (1) according to the example of the present invention has a structure in which a sulfamide acid group is introduced into only part of the side chain of the polyamic acid as a result of each reaction. Since each reaction form of the side chain of an acid is not limited, it is also possible to convert not only a part of the side chain of a polyamic acid but a whole side chain, for example to a sulfamide acid group.

In addition, as described above, a and b in the polyamic acid derivative represented by the general formula (2) are 0 ≦ a ≦ 2, 0 ≦ b ≦ 2, provided that a + b = 2, and each functional group has a different ratio. Exists as.

Next, as the aromatic hydrocarbon polymer having a sulfonic acid group, a polyether ether ketone derivative represented by the following general formula (2) is preferable.

(2)

In said formula, m is average polymerization degree, The range of 100-10000 is preferable.

If the average degree of polymerization is less than 100, a film cannot be formed, and if the average degree of polymerization exceeds 10000, it becomes difficult to be dissolved in a solvent, and a cast film which is very suitable as a means of complexing with a compound having an electron donating functional group becomes impossible.

Moreover, as another example of the aromatic hydrocarbon type polymer which has an acidic functional group, heat resistant polymers, such as a polyether ketone, a polyether sulfone, a polyphenylene ether, a polyphenylene sulfide, a polyimide, polybenzoxazole, can be illustrated.

(Compound Having Electron Donating Functional Group)

An electron donating functional group is also called an electron donating group, and is a functional group which increases an electron density in the specific site of a molecule | numerator by the difference of an electronegativity, resonance effect, and organic effect, and gives an electron to a partner. For this reason, the dissociable protons of the acidic functional group contained in the polymer and the portion of which the electron density is high act, and the proton conductivity is expressed by moving the prodonating functional moiety of the electron donor functional group present in the system.

As a compound which has an electron-donating functional group, the compound which is liquid at least at 100 degreeC-200 degreeC which is a fuel cell operation temperature is preferable. That is, a compound having a melting point of 100 ° C. or higher, particularly 110 to 130 ° C., having a boiling point of 200 ° C. or lower, particularly 160 to 190 ° C. is preferable. As an electron donating functional group, an amide group, an ether group, an amino group, a hydroxyl group, a thioether group, a C1-C20 alkyl group, a halogen group, etc. can be illustrated.

As a compound which has these electron-donating functional groups, decylamine, undecylamine, dodecylamine, tridecylamine, tridodecylamine, pentadecylamine, decylaniline, 4-butylaniline, 1-decanol, 2-decane Ol, 1-undecanol, 1-dodecanol, 2-dodecanol, 1-tridecanol, 1-tetradecanol, 2-tetradecanol, 2-hexadecanol, 2-hexyl-1-decanol, Heptadecanol, 1,10-decanediol, 1,2-decanediol, 1,12-dodecanediol, 1,2-tetradecanediol, 1,14-tetradecanediol, 1-decanethiol, 1-unde Canthiol, 1-pentadecanthiol, and the like.

Among them, an effective electron donating functional group may be an amide group or an ether group. Examples of the compound having these electron donating functional groups include diethyl dodecanoic acid amide, diethyl octadecanoic acid amide, diethyl benzamide, and diethyl-4-. Heptyl benzamide, diphenyl ether, ethylphenyl ether, cyclohexylphenyl ether, etc. are mentioned.

In the proton conductive polymer electrolyte of the present invention, the aromatic hydrocarbon polymer contains a compound having an electron donating functional group, and the aromatic hydrocarbon polymer and the compound having an electron donating functional group are mixed with each other in a homogeneous state. It is.

As for the mixing ratio of the compound which has an electron donating functional group, 0.01-50 weight part is preferable based on 100 weight part of aromatic hydrocarbon type polymers which have an acidic functional group . If the mixing ratio of the compound having an electron donating functional group is less than 0.01 part by weight, sufficient proton conductivity cannot be obtained. If the content exceeds 50 parts by weight, the strength of the film is lowered, which is not preferable.

As a method for producing a proton conductive polymer electrolyte according to the present invention, for example, an aromatic hydrocarbon polymer is dissolved in a solvent to obtain a polymer solution, and a mixed solution is prepared by adding a compound having an electron donating functional group to the polymer solution. What is necessary is just to manufacture, by cast-forming this mixed solution, and removing a solvent by means, such as a heating, reduced pressure, and a pressure reduction.

As a solvent for dissolving the aromatic hydrocarbon polymer, for example, when the aromatic hydrocarbon polymer is the polyamic acid derivative, dimethylformamide (DMF), N, N'-dimethylacetamide (DMAc), and N-methylpi Ralidone (NMP), dimethyl sulfoxide (DMSO), etc. can be used.

[Fuel cell]

1 is an exploded perspective view showing an example of the fuel cell of the present embodiment, and FIG. 2 is a cross-sectional schematic diagram of the membrane-electrode assembly constituting the fuel cell of FIG. 1.

In the fuel cell 1 shown in FIG. 1, two unit cells 11 are sandwiched by a pair of holders 12 and 12 and are schematically configured. The unit cell 11 is composed of the membrane-electrode assembly 10 and the bipolar plates 20 and 20 disposed on both sides of the membrane-electrode assembly 10 in the thickness direction, and the operating temperature is 100 ° C. to 200 ° C. and the humidity. It operates under conditions of no humidification or relative humidity below 50%. The bipolar plates 20 and 20 are made of a conductive metal or carbon, and are bonded to the membrane-electrode assembly 10 to function as a current collector and to the catalyst layer of the membrane-electrode assembly 10. Oxygen and fuel.

In addition, although the number of unit cells 11 is two, the fuel cell 1 shown in FIG. 1 is not limited to two, You may increase to several tens-hundreds according to the characteristic requested | required of a fuel cell.

As shown in FIG. 2, the membrane-electrode assembly 10 includes the electrolyte membrane 100, the catalyst layers 110 and 110 ′ disposed on both sides in the thickness direction of the electrolyte membrane 100, and the catalyst layers 110 and 110 ′. ) And first gas diffusion layers 121 and 121 'respectively stacked on the top surface, and second gas diffusion layers 120 and 120' stacked on the first gas diffusion layers 121 and 121 ', respectively.

The electrolyte membrane 100 is composed of the above-described proton conductive polymer electrolyte, and is composed of a composition containing at least an aromatic hydrocarbon polymer having an acidic functional group and a compound having an electron donating functional group. As for the film thickness of the electrolyte membrane 100, the range of about 20 micrometers-about 200 micrometers is preferable.

The catalyst layers 110 and 110 'function as a fuel electrode and an oxygen electrode, and each includes a catalyst material mainly composed of activated carbon or the like and a binder for solidifying the catalyst material. The catalyst material is composed of a catalyst material supported on activated carbon or the like. The catalytic material is not particularly limited as long as it is a metal that promotes the oxidation reaction of hydrogen and the reduction reaction of oxygen, for example, lead, iron, manganese, cobalt, chromium, gallium, vanadium, tungsten, ruthenium, iridium, palladium, platinum , Rhodium or their alloys. The catalyst material can be constituted by supporting such a metal or alloy on activated carbon.

As the binder, a fluororesin excellent in heat resistance may be used, or the proton conductive polymer electrolyte of the present invention may be used. By using a proton conductive polymer electrolyte as the binder, proton diffusion in the catalyst layers 110 and 110 'is efficiently performed, and impedances of the catalyst layers 110 and 110' are lowered to improve the output of the fuel cell.

In the case of using a fluororesin as a binder, a fluorine resin having a melting point of 400 ° C. or less is preferable, and as such a fluororesin, a polytetrafluoroethylene, a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and a polyfluorinated compound are used. Resin excellent in hydrophobicity and heat resistance, such as vinylidene, a tetrafluoroethylene hexafluoroethylene copolymer, and a perfluoroethylene, can be used. By adding a hydrophobic binder, it is possible to prevent the catalyst layers 110 and 110 'from excessively getting wet by the water generated in conjunction with the power generation reaction, and to prevent the diffusion of fuel gas and oxygen inside the fuel electrode and the oxygen electrode. can do.

In addition, a conductive material may be added to the catalyst layers 110 and 110 '. As an electrically conductive material, what kind of thing may be sufficient as it is an electrically conductive substance, and various metals, a carbon material, etc. are mentioned. For example, carbon black, such as acetylene black, activated carbon, graphite, etc. are mentioned, These are used individually or in mixture.

The first gas diffusion layers 121 and 121 'and the second gas diffusion layers 120 and 120' are each formed of, for example, carbon sheets and the like, and oxygen and fuel supplied via the bipolar plates 20 and 20 are respectively. Is diffused to the entire surface of the catalyst layers (110, 110 ').

The fuel cell 1 including the membrane-electrode assembly 10 operates at a temperature of 100 ° C. to 200 ° C., and is supplied with hydrogen, for example, as fuel through the bipolar plate 20 on one side of the catalyst layer. On the other side of the catalyst layer, for example, oxygen is supplied as an oxidant via the bipolar plate 20. Hydrogen is oxidized in one catalyst layer to produce protons, and the protons conduct the electrolyte membrane 4 to reach the other catalyst layer. In the other catalyst layer, protons and oxygen react electrochemically to produce water. At the same time, it generates electrical energy.

In addition, hydrogen supplied as a fuel may be hydrogen generated by the reforming of a hydrocarbon or alcohol, and oxygen supplied as an oxidant may be supplied in a state contained in air.

As described above, according to the proton conductive polymer electrolyte according to the present invention, when the aromatic hydrocarbon polymer contains a compound having an electron donating functional group, the acid and electron donating functional groups of the proton donor included in the aromatic hydrocarbon polymer Since it interacts with each other and proton conductivity is expressed, it can be used suitably as electrolyte of a fuel cell.

In addition, since the compound having an electron donating functional group according to the present invention exhibits insolubility in water, there is no fear that it will be dissolved in water generated by the power generation reaction of the fuel cell, and the compound having an electron donating functional group is removed from the electrolyte. There is no fear of leakage.

In addition, by using the polyamic acid derivative as an aromatic hydrocarbon-based polymer, proton conductivity can be expressed by the interaction of the sulfamic acid group of the polyamic acid derivative with the electron donating functional group of the compound having the electron donating functional group. At the same time, flexibility in forming a film on the electrolyte membrane by the alkyl group included in the polyamic acid derivative can be enhanced.

In addition, according to the fuel cell, even in the operating conditions of 100 ° C to 200 ° C operating temperature or less humidity or less than 50% of the relative humidity, a solid current exhibiting a high current density, high output, long life, good power generation performance stably for a long time A polymer fuel cell can be obtained and can be used suitably for automobiles, household power generation, or portable devices.

Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited by the following example.

(Example 1)

Synthesis of Polyamic Acid

As a polyamic acid that is a precursor of a polyamic acid derivative, a compound of Formula 1 (substituent Ar is a phenyl group, substituent R is a (CH ₂ ) ₁₀ group) was produced, and a precursor was synthesized as follows.

3.45 g (20 mmol) of 1,10-diaminodecane was dissolved in 170 mL of anhydrous N, N'-dimethylformamide (DMF), and 4.36 g (20 mmol) of pyromellitic anhydride recrystallized from acetone / hexane was added slowly, 15 It stirred at 700 degreeC for 1 hour at 60 degreeC, 60 hours at 25 degreeC, and made it react. The reaction solution was precipitated in 4 L of acetone / hydrochloric acid (1/4), recovered by filtration, washed with 1 mol / L aqueous hydrochloric acid solution, acetone, and dried under vacuum at 60 ° C. for 36 hours to obtain the following formula (3). Polyamic acid (polyamic acid 1) was obtained as a white powder of 7.65 g (98% yield).

The ¹ H-NMR spectrum (DMSO-d ₆ , 500 MHz) of the obtained white powder was 1.20-1.38 (br, -CH _2- ), 1.43-1.57 (br, -CH _2- ), 3.13-3.24 (br, -CH _2- ), 7.34, 7.68, 8.08 (s, Ph), 8.39, 8.44 (m, NH), and also the absorption from carbonyl group in the IR spectrum (1719 cm ^-1 , 1655 cm ^-1 (vc = o) ).

In addition, the polymer is soluble in DMF, N, N'-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO) and the like, and water, methanol, chloroform, hexane, benzene and It was insoluble in toluene.

(3)

Synthesis of Polyamic Acid Derivatives

1.17 g (3 unit mmol) of the polyamic acid 1 synthesized according to the above-described manufacturing process was dissolved in 100 mL of anhydrous DMF, and 1.78 g (15 mmol) of thionyl chloride was slowly added dropwise under a nitrogen atmosphere, and 6 hours at room temperature. The mixture was stirred to prepare a polymer solution.

Next, 2.91 g (30 mmol) of amido sulfate (manufactured by Kishida Chemical Co., Ltd.) and 3.03 g (30 mmol) of triethylamine were mixed with 15 mL of anhydrous dichloromethane to form amido sulfate triethylamine salt, and then, under nitrogen atmosphere. It was dripped gradually to the said polymer solution, and it stirred at room temperature for 16 hours.

After evaporating the solvent in the reaction solution at 50 ° C. under reduced pressure, 100 mL of pure water was added to the viscous body, and the mixture was stirred at room temperature for 1 hour. Thereafter, the solution was centrifuged at 4000 rpm for 10 minutes, after which the supernatant was removed, and the remaining solids were filtered out. The recovered product was dissolved in 100 mL of DMF, passed through 250 mL of a cation exchange resin (Amberlyst 15JWET manufactured by Organo), and proton exchange was performed.

The solution was concentrated to 10 mL, added dropwise into 20 mL of pure water, the precipitate was filtered off, dried under vacuum at 70 ° C. for one day, and 0.68 g of a polyamic acid derivative 2 represented by the following formula (4) as a pale brown powder (yield). 42%). Moreover, the ratio of a and b was a: b = 9: 1 from the elemental analysis of sulfur. In addition, the average degree of polymerization was about 200.

The ¹ H-NMR spectrum (DMSO-d ₆ , 500 MHz) of the obtained pale brown powder was 1.20-1.35 (br, -CH _2- ), 1.49-1.65 (br, -CH _2- ), 3.20-3.30 (m,- The spectrum of CH _2- ), 3.52-3.64 (m, -CH _2- ), and absorption from carbonyl group in the IR spectrum (1716cm ^-1 , 1635cm ^-1 (vc = o)) and sulfamide acid groups It showed an absorption ^{(1192cm -1, 1055cm -1 (vs} = o)).

The polymer was soluble in DMF, DNAc, NMP, DMSO and the like and insoluble in water, methanol, chloroform, hexane, benzene and toluene.

[Formula 4]

0.95 g of the polyamic acid derivative and 0.05 g of diethyldodecanoic acid amide obtained according to the above procedure were dissolved in 9 g of dimethylformamide, and cast film was formed at 60 ° C. to obtain a light brown film having a thickness of 50 μm. In this way, the proton conductive polymer electrolyte membrane of Example 1 was prepared.

`` Proton conductivity measurement ''

The proton conductive polymer electrolyte membrane of Example 1 was inserted into a disk-shaped platinum electrode having a diameter of 13 mm, and ion conductivity was determined from the complex impedance measurement. The temperature dependence of proton conductivity is shown in FIG. 3. Ionic conductivity at 150 ° C. was 5.8 × 10 ⁻³ Scm ⁻¹ .

`` Fuel cell evaluation ''

Next, carbon powder loaded with 50% by weight of platinum was added to the DMAc solution of the electrolyte membrane prepared in Example 1, which was sufficiently stirred to obtain a suspension. At this time, the weight ratio of the platinum-carrying carbon powder and the proton conductive electrolyte was adjusted to be 2: 1 by weight ratio of the solid content. This suspension was applied onto a carbon porous body (porosity 75%) and dried to form a porous electrode for a fuel cell.

Then, the unit cell was formed by sandwiching the electrolyte membrane obtained in Example 1 between the pair of porous electrodes. A power generation test was conducted at 150 ° C. by supplying hydrogen as a fuel and air as an oxidant, respectively, and a voltage of 0.589 V was obtained at a current density of 100 mA / cm ² at a 0.99 V opening voltage.

(Examples 2 to 7)

`` Another example of electrolyte membrane ''

Instead of the polyamic acid derivative in Example 1, the aromatic hydrocarbon polymer (polymer) shown in Table 1 was used, and instead of the diethyldodecanoic acid amide in Example 1, electron donating shown in Table 1 below The electrolyte membrane of Examples 1-7 was produced like Example 1 except having used the compound (second component) which has a functional group, and mixing these at the ratio shown in Table 1.

With respect to the obtained electrolyte membrane, the proton conductivity was measured in the same manner as in Example 1, and the fuel cell was evaluated.

In addition, the polymer in Example 2 and 4-7 is the same as that of the polymer in Example 1. The polymer in Example 3 was obtained as a yellow powder, and the ¹ H-NMR spectrum (DMSO-d ₆ , 500 MHz) of this powder showed the spectrum of 7.02, 7.16, 7.55, 7.66 (s, Ph), Moreover, the absorption (1644 cm <^-1> (vc = o)) derived from the carbonyl group and the absorption (1222 cm <^-1> (vs = o)) derived from a sulfonic acid group were shown in IR spectrum. In addition, the average degree of polymerization was about 250.

The polymer in this Example 3 was soluble in DMF, DNAc, NMP, DMSO and the like and was insoluble in water, methanol, chloroform, hexane, benzene, and toluene.

As the second component in Example 7, Polyethylene Glycol # 600 (Mw = 600) manufactured by Tokyo Chemical Co., Ltd. was used.

(Comparative Example)

Biphenyl is used instead of diethyldodecanoic acid amide, and this biphenyl is added to DMF together with the polyamic acid derivative represented by formula (10) to prepare a DMF solution, which is cast on a glass plate and dried by heating at 60 ° C. In the same manner as in Example 1, except for preparing the electrolyte membrane of Comparative Example 1. The electrolyte membrane of Comparative Example 1 was a light brown membrane.

[Table 1]

In Table 1, "open circuit voltage" represents "open circuit voltage."

As shown in Table 1, the electrolyte membranes of Examples 2 to 7 show excellent values of both the proton conductivity of the membrane alone and the open circuit voltage in the case of the fuel cell. In these electrolyte membranes, either one of an ether group or an amide group is included as an electron donating functional group in the compound added as the second component, and the sulfamide group or sulfide contained in these electron donating functional groups and an aromatic hydrocarbon-based polymer. High proton conductivity is expressed by the interaction of the phone groups.

On the other hand, in Comparative Example 1, the proton conductivity of the membrane alone was low enough to be undetectable, and the open circuit voltage in the case of the fuel cell was not obtained as a stable value, and showed very high resistance.

In Comparative Example 1, since the compound added as the second component does not contain an electron donating functional group such as an ether group or an amide group, the interaction with the acidic functional group contained in the aromatic hydrocarbon polymer does not occur, and sufficient proton conductivity is achieved. Expressed.

1 is a perspective exploded view showing a main part of a fuel cell according to an embodiment of the present invention;

FIG. 2 is a cross-sectional schematic diagram illustrating a membrane-electrode assembly provided in the fuel cell of FIG. 1.

3 is a graph showing the temperature dependence of proton conductivity of the electrolyte membrane of Example 1. FIG.

BRIEF DESCRIPTION OF THE MAIN SIGNS IN THE FIGURE

1 ... fuel cell 10 ... membrane-electrode assembly

20 ... Bipolar Plate

100. Electrolyte Membrane (Proton Conductive Polymer Electrolyte)

110, 110 '... catalyst bed

120, 120 ', 121, 121' ... gas diffusion layer

Claims (7)

An aromatic hydrocarbon polymer having an acidic functional group and a composition containing at least a compound having an electron donating functional group; A proton conductive polymer electrolyte, wherein the aromatic hydrocarbon-based polymer having an acidic functional group is a polyamic acid derivative represented by Formula 1 below: [Formula 1]

Wherein Ar is a group containing an aromatic ring or an aromatic ring, R is a C1-C20 alkylene group, 0 ≦ a ≦ 2, 0 ≦ b ≦ 2, provided that a + b = 2, n is an integer of 100-10000 as average degree of polymerization. The compound according to claim 1, wherein the compound having an electron donating functional group is Proton conductive polymer electrolyte, characterized in that contained in the range of 0.01 to 50% by weight relative to the aromatic hydrocarbon polymer having an acidic functional group. The proton conductive polymer electrolyte according to claim 1, wherein the compound having an electron donating functional group has a melting point of 100 ° C or higher and a boiling point of 200 ° C or lower. The proton conductive polymer electrolyte according to claim 1, wherein the acidic functional group is a sulfonic acid group or a sulfamide acid group. delete A pair of electrodes and an electrolyte membrane disposed between the electrodes, A fuel cell, wherein the electrolyte membrane is the proton conductive polymer electrolyte of any one of claims 1 to 4. The fuel cell according to claim 6, wherein a part of the electrode contains a proton conductive polymer electrolyte comprising an aromatic hydrocarbon polymer having an acidic functional group and a composition containing at least a compound having an electron donating functional group.

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