KR100714362B1 - Electrolyte for fuel cell, membrane and electrode assembly, and method for manufacturing the electrolyte for fuel cell - Google Patents

Abstract

In a fuel cell electrolyte containing a basic polymer, dimensional change before and after acid addition is suppressed and wrinkles and the like are reduced. The electrolyte for a fuel cell of the present invention includes a basic polymer and an organic phosphonic acid represented by the following Chemical Formula 1.

[Formula 1]

In formula, R represents a C1-C20 alkyl group, a C6-C20 aryl group, a C1-C20 acyl group, an amino group, a phosphone group, or derivatives of these functional groups, n is 1 or 2 .

Description

Electrolyte for fuel cell, membrane and electrode assembly, and method for manufacturing the electrolyte for fuel cell}

1 is a diagram schematically showing a TG chart for calculating moisture content.

2 is a graph showing the time-dependent change in moisture content measured by the above-described moisture content evaluation method for Example 1 and Comparative Example 1, which were stored at 22 占 폚, 62% RH after acid addition.

FIG. 3 is a graph showing the results of measurement of changes in the open circuit voltage and cell resistance over time with respect to the electrolyte for fuel cells of Example 2 under conditions of 150 ° C. and no humidification.

4 is a graph showing the current-voltage characteristics of Example 2 and Comparative Example 2. FIG.

TECHNICAL FIELD The present invention relates to a fuel cell, and more particularly, to an electrolyte membrane and a membrane electrode assembly for a fuel cell, which can be used for a fuel cell that can operate in a non-humidified state.

BACKGROUND OF THE INVENTION A solid polymer fuel cell using a solid polymer membrane as an electrolyte is known. The solid polymer fuel cell uses a proton conductive polymer electrolyte membrane as an electrolyte and generally includes an anode (fuel electrode), a cathode (oxidant electrode), and a polymer electrolyte membrane disposed between the anode and the cathode. The anode of the polymer electrolyte fuel cell is provided with a catalyst layer for promoting oxidation of the fuel, and the cathode of the polymer electrolyte fuel cell is provided with a catalyst layer for promoting reduction of the oxidant.

As a fuel supplied to the anode of the solid polymer fuel cell, hydrogen, a hydrogen-containing gas, a mixed vapor of methanol and water, an aqueous methanol solution and the like are generally used. As the oxidant supplied to the cathode of the solid polymer fuel cell, oxygen, oxygen-containing gas or air is generally used.

As a material of the polymer electrolyte membrane, a sulfonate high fluorinated polymer having a main chain generally composed of fluorinated alkylene and a side chain composed of fluorinated vinyl ether having a sulfonic acid group at its terminal is used. This type of polymer electrolyte membrane is impregnated with an appropriate amount of water to exhibit sufficient ion conductivity for power generation.

For this reason, in the conventional solid polymer fuel cell, it is necessary to manage the moisture of the polymer electrolyte membrane, resulting in the complexity and enlargement of the fuel cell system.

In order to avoid the problem due to the moisture management of the polymer electrolyte membrane, as a means of replacing the conventional polymer electrolyte membrane, a humidified electrolyte membrane capable of proton conduction in a non-humidified state has been developed.

For example, Japanese Patent Laid-Open No. 11-503262 discloses a material such as polybenzimidazole doped with phosphoric acid as a humidified polymer electrolyte membrane.

When phosphoric acid is doped into a basic polymer film such as polybenzimidazole, the basic polymer film causes dimensional change due to hygroscopicity of phosphoric acid. In addition, the phosphoric acid is absorbed to release the phosphoric acid from the basic polymer film. As a result, the basic polymer film shrinks, causing wrinkles in the basic polymer film. For this reason, for storage of the produced basic polymer membrane, membrane electrode assembly, or stack assembly, special environmental facilities such as a dry room are required, which causes problems such as difficulty in manufacturing and increase in manufacturing cost.

This invention is made | formed in view of the above-mentioned subject, and the objective is to provide the electrolyte for fuel cells containing the basic polymer in which the dimensional change before and after acid addition is suppressed and wrinkles etc. are few. Another object of the present invention is to provide a membrane electrode assembly using an electrolyte for fuel cells containing a basic polymer, wherein the membrane electrode assembly has improved gas diffusivity.

An embodiment of the present invention is a fuel cell electrolyte. The fuel cell electrolyte is characterized by containing a basic polymer and an organic phosphonic acid represented by the following formula (1).

[Formula 1]

In the formula, R represents a C1-C20 alkyl group, a C6-C20 aryl group, a C1-C20 acyl group, an amino group, a phosphone group or a derivative of these functional groups, and n is 1 or 2.

According to this, a fuel cell electrolyte is obtained in which the proton conductivity is at the same level as that of the conventional fuel cell electrolyte, and the dimensional change and the generation of wrinkles are suppressed.

In the fuel cell electrolyte, the basic polymer is polybenzimidazole, poly (pyridine), poly (pyrimidine), polyimidazole, polybenzothiazole, polybenzoxazole, polyoxadiazole, poly It is preferable that it is at least one selected from the group consisting of quinolines, polyquinoxalines, polythiadiazoles, poly (tetradipyrenes), polyoxazoles, polythiazoles, polyvinylpyridines and polyvinylimidazoles. In the fuel cell electrolyte as an example, the basic polymer may contain poly-2,5-benzimidazole.

In the fuel cell electrolyte, the organic phosphonic acid is preferably at least one selected from the group consisting of ethylphosphonic acid, methylphosphonic acid and octylphosphonic acid.

The water content of the electrolyte for fuel cell may be 20% or less. In addition, the definition of a moisture content is mentioned later. Further, as an example, the stretching ratio of the electrolyte for fuel cells may be 20% or less. In addition, the definition of an expansion ratio is mentioned later.

Another embodiment of the present invention is a membrane electrode assembly. The membrane electrode assembly includes any one of the fuel cell electrolytes described above, an anode bonded to one side of the fuel cell electrolyte, and a cathode bonded to the other side of the fuel cell electrolyte, and includes at least an anode and a cathode. One side is characterized by comprising an organic phosphonic acid represented by the formula (1).

According to this, a special facility such as a dry room is required to manufacture a membrane electrode assembly by using a fuel cell electrolyte having a proton conductivity equal to that of a conventional fuel cell electrolyte and suppressing dimensional change, wrinkles, and the like. Since it does not, manufacturing cost is saved. In addition, by adding organic phosphonic acid to at least one of the anode and the cathode, the interfacial resistance between the electrode (anode and / or cathode) and the fuel cell electrolyte is reduced, and the gas diffusivity is improved.

In the membrane electrode assembly, at least one of the anode and the cathode may include an organic phosphonic acid selected from the group consisting of ethylphosphonic acid, methylphosphonic acid, and octylphosphonic acid.

In the membrane electrode assembly, the sum of the content of the organic phosphonic acid contained in the fuel cell electrolyte, the organic phosphonic acid contained in the anode, and the content of the organic phosphonic acid contained in the cathode is 100-800 mol% of the basic polymer. do.

Another embodiment of the present invention is a membrane electrode assembly. The membrane electrode assembly includes any one of the fuel cell electrolytes described above, an anode bonded to one side of the fuel cell electrolyte, and a cathode bonded to the other side of the fuel cell electrolyte, and at least one of the anode and the cathode It is characterized by including a hydrolyzable phosphoric acid compound represented by the following formula (2).

[Formula 2]

In the formula, R represents a C1-C20 alkyl group or a C1-C20 alkoxyalkyl group, n is 1 or 2.

According to this, a special facility such as a dry room is required to manufacture a membrane electrode assembly by using a fuel cell electrolyte having a proton conductivity equal to that of a conventional fuel cell electrolyte and suppressing dimensional change, wrinkles, and the like. Since it does not, manufacturing cost is reduced. In addition, by adding a phosphoric acid compound to at least one of the anode and the cathode, the interface resistance between the electrode (anode and / or cathode) and the fuel cell electrolyte is reduced, and the gas diffusivity is improved.

In the membrane electrode assembly, at least one of the anode and the cathode may include one or more phosphoric acid compounds selected from the group consisting of ethyl phosphate, methyl phosphate, butyl phosphate, oleate phosphate and dibutyl phosphate.

In the membrane electrode assembly, at least one of the anode and the cathode may include at least one phosphoric acid compound selected from the group consisting of monoethyl phosphate, monomethyl phosphate, mono n-butyl phosphate and mono n-octyl phosphate.

In the above membrane electrode assembly, the total of the phosphoric acid compound content contained in the content of the phosphate compound, the content of the phosphate compound and the cathode contained in the anode included in the fuel cell, the electrolyte may be 5-800 mol% of the basic polymer.

Another embodiment of the present invention is a method for producing an electrolyte for fuel cells. The fuel cell electrolyte production method includes a step of forming a basic polymer and a step of impregnating the basic polymer in an aqueous solution in which the organic phosphonic acid represented by the formula (1) is dissolved.

In the fuel cell electrolyte production method, the organic phosphonic acid may be one or more selected from the group consisting of ethyl phosphonic acid, methyl phosphonic acid and octyl phosphonic acid.

Moreover, what suitably assembled each element mentioned above can also be included in the scope of the invention which requires protection by a patent by this patent application.

(1st embodiment)

The fuel cell electrolyte according to the present embodiment contains a basic polymer and an organic phosphonic acid represented by the following general formula (1).

[Formula 1]

In the formula, R represents a C1-C20 alkyl group, a C6-C20 aryl group, a C1-C20 acyl group, an amino group, a phosphone group or a derivative of these functional groups, and n is 1 or 2.

(Basic polymer)

Basic polymers are polybenzimidazoles, poly (pyridines), poly (pyrimidines), polyimidazoles, polybenzothiazoles, polybenzoxazoles, polyoxadiazoles, polyquinolines, poly It is preferably at least one selected from the group consisting of quinoxalines, polythiadiazoles, poly (tetradipyrenes), polyoxazoles, polythiazoles, polyvinylpyridines and polyvinylimidazoles.

It is also preferred that the basic polymer comprises poly-2,5-benzimidazole.

(Organic phosphonic acid)

The organic phosphonic acid is preferably at least one selected from the group consisting of ethyl phosphonic acid, methyl phosphonic acid and octyl phosphonic acid.

In the fuel cell electrolyte according to the present embodiment, the water content determined by the water content evaluation method described later is suppressed to 20% or less, more preferably 10% or less.

In the fuel cell electrolyte according to the present embodiment, the expansion rate obtained by the expansion rate evaluation method described later is suppressed to 20% or less, more preferably 10% or less.

In the fuel cell electrolyte according to the present embodiment, since the organic phosphonic acid lacking the absorbency is used as the acid added to the basic polymer, the phosphate compound has a characteristic that there is little dimensional change and wrinkles are not easily generated before and after the addition of the phosphate compound. .

The fuel cell electrolyte according to the present embodiment is obtained by impregnating a basic polymer in an organic phosphonic acid aqueous solution. For this reason, the water content of the organic phosphonic acid gradually decreases with time as in the drying step, the step of embedding in the fuel cell, and the step used as a product after the impregnation. After being embedded in a fuel cell and becoming a product, when the battery is operated under normal conditions, for example, 150 ° C. and no humidification, the water content of the electrolyte for the fuel cell finally becomes almost zero.

(Water content evaluation method)

An evaluation method of the water content of the electrolyte for fuel cell will be described below.

First, thermogravimetric measurement (TG) is performed on the organic phosphonic acid itself added to the basic polymer, and the temperature T1 at which the rapid mass reduction occurs due to decomposition or dehydration of the organic phosphonic acid is grasped. When the temperature T1 is about 150 ° C. or higher, it is confirmed that the weight loss up to about 100 ° C. is due to the evaporation of water contained in the sample regardless of the organic phosphonic acid with respect to the sample whose moisture content is to be measured. Moreover, about each organic phosphonic acid mentioned above, it is confirmed that there is no sudden mass loss to 160 degreeC.

Next, TG measurement is performed on the sample to be measured for moisture content. 1 schematically shows a TG chart for calculating the moisture content. In FIG. 1, the mass change before and after the temperature of 100 degreeC is caused by evaporation of the water contained in a sample irrespective of organic phosphonic acid. The mass change before and after the temperature T1 is due to decomposition or dehydration of the organic phosphonic acid. The weights W1 and W2 corresponding to the inflection points S1 and S2 of the mass change before and after the temperature T1 are respectively measured. The moisture content is obtained by a calculation formula such that the moisture content = (W1-W2) / W1 * 100.

Moreover, it is very suitable to calculate | require the temperature corresponding to inflection point S1, S2 from undivided gravimetric method (DTG). In the DTG, since the positions of the inflection points S1 and S2 appear as peaks, the weights of the inflection points S1 and S2 can be determined from the peak positions of the DTG.

(Expansion rate evaluation method)

The calculation method of the expansion ratio S of the electrolyte for fuel cells will be described below. The expansion ratio S is obtained by a calculation equation in which S = (Y-X) / X * 100 (%). Here, X represents a predetermined length of the fuel cell electrolyte before adding the organic phosphonic acid to the basic polymer, and Y represents the predetermined amount of the electrolyte for the fuel cell at any time after adding the organic phosphonic acid to the basic polymer. Indicate the length of the neighborhood.

(2nd embodiment)

The membrane electrode assembly of the present embodiment is obtained by bonding an anode to one side of the fuel cell electrolyte described above and a cathode to the other side of the fuel cell electrolyte.

The membrane electrode assembly of the present embodiment is characterized in that at least one of the anode and the cathode contains an organic phosphonic acid represented by the formula (1). In the membrane electrode assembly of the present embodiment, since the proton conductivity is at the same level as the conventional fuel cell electrolyte, and the fuel cell electrolyte is suppressed in which the dimensional change, wrinkles, etc. are suppressed, in order to manufacture the membrane electrode assembly, a dry room Since no special equipment such as the above is required, manufacturing cost is reduced. By adding organic phosphonic acid to at least one of the anode and the cathode, the interfacial resistance between the electrode and the fuel cell electrolyte is reduced, and the gas diffusivity is improved.

The anode or the cathode to which the phosphoric acid compound is added is obtained by coating the phosphoric acid compound on the anode or the cathode, followed by drying at 80 ° C. for 120 minutes. The drying temperature and drying time can be appropriately changed.

The organic phosphonic acid contained in at least one of the anode and the cathode is preferably one or more selected from the group consisting of ethyl phosphonic acid, methyl phosphonic acid and octyl phosphonic acid.

In the membrane electrode assembly according to the present embodiment, the sum of the content of the organic phosphonic acid contained in the fuel cell electrolyte, the organic phosphonic acid contained in the anode, and the content of the organic phosphonic acid contained in the cathode is basic. It is preferred that it is 100-800 mol% of the polymer.

Since the total amount of organic phosphonic acid is in the range of 100-800 mol% of the basic polymer, sufficient proton conductivity for power generation conditions is obtained, so that the required amount of organic phosphonic acid is solved. For this reason, the manufacturing cost of a membrane electrode assembly can be reduced.

When organic phosphonic acid is added to both the anode and the cathode, it is preferable that the content of the organic phosphonic acid added to the anode is higher than the content of the organic phosphonic acid added to the cathode.

As a result, the interface resistance between the electrode and the fuel cell electrolyte can be further reduced, and the gas diffusivity can be further improved.

(Third embodiment)

The membrane electrode assembly of the present embodiment is obtained by bonding an anode to one side of the fuel cell electrolyte described above and a cathode to the other side of the fuel cell electrolyte.

The membrane electrode assembly of the present embodiment is characterized in that at least one of the anode and the cathode contains a phosphate compound represented by the following formula (2).

[Formula 2]

In the formula, R represents a C1-C20 alkyl group or a C1-C20 alkoxyalkyl group, n is 1 or 2.

As the membrane electrode assembly of the present embodiment, a fuel cell electrolyte having a proton conductivity equivalent to that of a conventional fuel cell electrolyte and suppressing dimensional change, wrinkles, and the like is used. Since no special equipment such as a room is required, manufacturing costs are reduced. By adding a phosphoric acid compound to at least one of the anode and the cathode, the interface resistance between the electrode and the fuel cell electrolyte is reduced, and the gas diffusivity is improved.

The anode or the cathode to which the phosphoric acid compound is added is obtained by coating the phosphoric acid compound on the anode or the cathode, followed by drying at 80 ° C. for 120 minutes. The drying temperature and drying time can be appropriately changed.

The phosphoric acid compound contained in at least one of the anode and the cathode is preferably at least one selected from the group consisting of ethyl phosphate, methyl phosphate, butyl phosphate, oleate phosphate and dibutyl phosphate.

In addition, the phosphoric acid compound contained in at least one of the anode and the cathode is preferably at least one selected from the group consisting of monoethyl phosphate, monomethyl phosphate, mono n-butyl phosphate and mono n-octyl phosphate.

Moreover, it is preferable that the phosphoric acid compound contained in at least one of an anode and a cathode is butoxy ethyl phosphate.

In the membrane electrode assembly according to the present embodiment, the sum of the content of the phosphoric acid compound contained in the electrolyte for fuel cells, the content of the phosphoric acid compound contained in the anode, and the content of the phosphoric acid compound contained in the cathode is determined by the basic polymer. It is preferable that it is 5-800 mol%.

(Example 1)

Hereinafter, the manufacturing method in the case of using polybenzimidazole (PBI) as a basic polymer and ethyl phosphonic acid as organic phosphonic acid as a typical fuel cell electrolyte of this invention is demonstrated.

First, PBI (20%) is dissolved in dimethylacetoamide containing LiCl (2%). The PBI solution is cast on a glass plate to form a PBI film.

Next, 0.13 g (0.00042 mol) of PBI films were immersed in a 40% ethylphosphonic acid solution (solvent: water) at room temperature for 2 hours. The ethylphosphonic acid solution was kept at 60 degreeC in the hot water bath.

Thereafter, the PBI membrane was extracted, and the excess solvent adhering with Protex (trade name: ProTEX) was removed by washing away to obtain an electrolyte for a fuel cell. The weight after immersion was 0.22 g.

As will be described later, since the electrolyte for the fuel cell of this embodiment has a water content of almost zero, the mass of added ethylphosphonic acid is approximately 0.09 g (0.00081 mol). From this result, the doping rate of ethylphosphonic acid was 192 mol% based on PBI.

(Comparative Example 1)

For comparison with Example 1, an electrolyte for fuel cells obtained by adding phosphoric acid to PBI was prepared.

As in Example 1, after forming the PBI film, 0.15 g (0.00049 mol) of the PBI film was deposited in a 85% phosphoric acid solution in a beaker at room temperature for 24 hours.

Thereafter, the PBI film was extracted and removed by washing off the excess solvent adhered with Protex (trade name: ProTEX) to prepare an electrolyte for a fuel cell. The mass after deposition was 0.58 g. From these results, the doping rate of phosphoric acid was 900 mol% based on PBI.

(Evaluation result of water content)

2 is a graph showing the time change of the moisture content measured by the above-described moisture content evaluation method for Example 1 and Comparative Example 1 stored at 22 ° C. and 62% RH after acid addition.

In the fuel cell electrolyte of Comparative Example 1, it is understood that the moisture content increases with time due to the hygroscopicity of phosphoric acid. In the comparative example 1, the water content of 9 hours of phosphoric acid addition reached 25%. In Comparative Example 1, as a result of absorption of moisture in the atmosphere into the fuel cell electrolyte, a phenomenon in which the volume of the fuel cell electrolyte expanded and phosphoric acid leaked out of the fuel cell electrolyte was confirmed. For this reason, in the fuel cell electrolyte of Comparative Example 1, the total weight of phosphoric acid and PBI decreases with time.

On the other hand, in the electrolyte for fuel cells of Example 1, even when left in the air, there was almost no weight change, and it was confirmed that the above-mentioned problem was solved.

(Evaluation result of expansion rate)

Table 1 shows the stretching ratios before and after adding monoethyl phosphate and phosphoric acid to the fuel cell electrolytes of Example 1 and Comparative Example 1, respectively. Looking at the conditions after acid addition, 22 ℃, 62% RH, left for 9 hours. In the case of the comparative example 1, it is known that a stretch ratio is 25%, it is easy to produce wrinkles, and special correspondence is required, such as using a dry room, in order to assemble a membrane electrode assembly or a stack.

On the other hand, in Example 1, the stretching ratio was suppressed to 6%, and no dimensional change or occurrence of wrinkles was observed.

TABLE 1

Elongation rate (%) Example 1 25 Comparative Example 1 6

(Example 2)

A membrane electrode assembly was prepared by bonding an anode to one side of the fuel cell electrolyte obtained in Example 1 and a cathode to the other side. As the anode and the cathode, HT140E-W manufactured by E-TEK Corporation was used. To reduce the interfacial resistance between the electrolyte membrane and the electrode, ethylphosphonic acid was added to the surface of the anode and the cathode. The content of ethylphosphonic acid added to PBI, anode and cathode is 200 mol% based on PBI.

(Comparative Example 2)

A membrane electrode assembly was prepared by bonding an anode to one side of the fuel cell electrolyte obtained in Example 1 and a cathode to the other side. As the anode and the cathode, HT140E-W manufactured by E-TEK Corporation was used. In order to reduce the interfacial resistance between the electrolyte membrane and the electrode, 105 wt% phosphoric acid was added to the surface of the anode and the cathode. The amount of phosphoric acid added to the anode and the cathode is 800 mol% based on PBI.

(Measurement result of proton conductivity)

The fuel cell electrolytes obtained in Example 2 and Comparative Example 2 were each embedded in a fuel cell to measure proton conductivity. The temperature of the fuel cell at the time of proton conductivity measurement was 150 ° C, the flow rate of hydrogen, and the flow rate of air were 100 (NCCM) and 200 (NCCM), respectively. The electrode area for the fuel cell is 7.8 cm ² .

As a result, the proton conductivity of Comparative Example 2 was 7 × 10 ⁻² S / cm, whereas the proton conductivity of Example 2 was 6 × 10 ⁻² S / cm, and the proton conductivity of Example 2 was compared with that of Comparative Example 2. It was confirmed that it was at the same level.

(Time change of open circuit voltage and cell resistance)

Fig. 3 is a graph showing the results of measurement of changes in open circuit voltage and cell resistance over time in the fuel cell electrolyte of Example 2 under a condition of 150 ° C and no humidification. In the electrolyte for fuel cells of Example 2, good results have been confirmed that a drop in the open circuit voltage and a rise in cell resistance do not occur over 2000 hours.

(Measurement Result of Current-Voltage Characteristics)

The fuel cell electrolytes obtained in Example 2 and Comparative Example 2 were each embedded in a fuel cell, and current-voltage characteristics were measured. The temperature of the fuel cell at the time of current-voltage characteristic measurement is 150 degreeC, the flow volume of hydrogen, and the flow volume of air are 100 (NCCM) and 200 (NCCM), respectively. In addition, the electrode area for the fuel cell is 7.8 cm ² .

4 is a graph showing the current-voltage characteristics of Example 2 and Comparative Example 2. FIG. 0.3 (V) is more than the load that can be generated by the cell voltage, compared to Example 2, 0.8A / cm ^2, compared to the, second embodiment and promote to 1.0A / cm ^2, Example 2 in which the gas diffusibility is improved It can be seen that.

This is because phosphoric acid is a complete liquid, and mobility is high, and it is difficult to maintain a three-phase interface formed of a catalyst, a reaction gas, and an electrolyte by wetting, whereas ethylphosphonic acid has a small mobility and a three-phase system. This is because the cotton is easy to maintain.

According to the present invention, with respect to the fuel cell electrolyte using the basic polymer membrane, the dimensional change before and after the acid addition is suppressed, and the occurrence of wrinkles and the like is reduced. Such electrolytes can be used in fuel cells that can operate in a humidified state.

Claims (15)

It includes a basic polymer and an organic phosphonic acid represented by the formula (1), The organic phosphonic acid is at least one selected from the group consisting of ethyl phosphonic acid, methyl phosphonic acid, octyl phosphonic acid electrolyte for fuel cell. [Formula 1]

In the formula, R represents a C1-C20 alkyl group, a C6-C20 aryl group, a C1-C20 acyl group, an amino group, a phosphone group or a derivative of these functional groups, and n is 1 or 2. The basic polymer according to claim 1, wherein the basic polymer is polybenzimidazole, poly (pyridine), poly (pyrimidine), polyimidazole, polybenzothiazole, polybenzoxazole, polyoxadiazole, poly Consisting of quinolines, polyquinoxalines, polythiadiazoles, poly (tetra-di-pyrene), polyoxazoles, polythiazoles, polyvinylpyridines and polyvinylimidazoles The fuel cell electrolyte, characterized in that at least one selected from the group. The fuel cell electrolyte of claim 1, wherein the basic polymer comprises poly-2,5-benzimidazole. delete The fuel cell electrolyte of claim 1, wherein a water content of the electrolyte is 20% or less. The fuel cell electrolyte of claim 1, wherein the electrolyte has a stretch ratio of 20% or less. The fuel cell electrolyte of claim 1, 2, 3, 5, or 6, an anode bonded to one side of the fuel cell electrolyte, and a cathode bonded to the other side of the fuel cell electrolyte Equipped, The anode, the cathode or both the anode and the cathode, Membrane electrode assembly comprising an organic phosphonic acid represented by the formula (1). [Formula 1]

In the formula, R represents a C1-C20 alkyl group, a C6-C20 aryl group, a C1-C20 acyl group, an amino group, a phosphone group or a derivative of these functional groups, and n is 1 or 2. The method of claim 7, wherein the anode, the cathode or both the anode and cathode, Membrane electrode assembly comprising at least one organic phosphonic acid selected from the group consisting of ethyl phosphonic acid, methyl phosphonic acid, octyl phosphonic acid. The sum of the content of the organic phosphonic acid contained in the fuel cell electrolyte, the content of the organic phosphonic acid contained in the anode and the content of the organic phosphonic acid contained in the cathode is 100- of the basic polymer. Membrane electrode assembly, characterized in that in the range of 800 mol%. The fuel cell electrolyte of claim 1, 2, 3, 5, or 6, an anode bonded to one side of the fuel cell electrolyte, and a cathode bonded to the other side of the fuel cell electrolyte Equipped, A membrane electrode assembly, characterized in that the anode, the cathode or both the anode and the cathode comprises a hydrolyzable phosphoric acid compound represented by the following formula (2). [Formula 2]

In the formula, R represents a C1-C20 alkyl group or a C1-C20 alkoxyalkyl group, n is 1 or 2. The method of claim 10, wherein the anode, the cathode or both the anode and the cathode, A membrane electrode assembly comprising one or more phosphoric acid compounds selected from the group consisting of ethyl phosphate, methyl phosphate, butyl phosphate, oleic acid phosphate, and dibutyl phosphate. The method of claim 7, wherein the anode, the cathode or both the anode and cathode, A membrane electrode assembly comprising one or more phosphoric acid compounds selected from the group consisting of monoethyl phosphate, monomethyl phosphate, mono n-butyl phosphate and mono n-octyl phosphate. The method of claim 10, wherein the sum of the content of the organic phosphonic acid contained in the fuel cell electrolyte, the content of the phosphoric acid compound included in the anode and the content of the phosphoric acid compound contained in the cathode, Membrane electrode assembly, characterized in that 5-800 mol% of the basic polymer. Forming a basic polymer; And And impregnating the basic polymer in an aqueous solution in which organic phosphonic acid represented by Formula 1 is dissolved, wherein the organic phosphonic acid is at least one selected from the group consisting of ethyl phosphonic acid, methyl phosphonic acid and octyl phosphonic acid. A method for producing an electrolyte for a fuel cell. [Formula 1]

In the formula, R represents a C1-C20 alkyl group, a C6-C20 aryl group, a C1-C20 acyl group, an amino group, a phosphone group or a derivative of these functional groups, and n is 1 or 2. delete

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