JP4790225B2 - Gel electrolyte, electrode for fuel cell, fuel cell, and method for producing gel electrolyte - Google Patents

Description

  The present invention relates to a gel electrolyte, a fuel cell electrode, a fuel cell, and a method for producing a gel electrolyte, and more particularly to a gel electrolyte with improved mechanical strength.

  In fuel cells, from the viewpoint of power generation efficiency, system efficiency, and long-term durability of components, good protons can be obtained at operating temperatures of about 100 ° C to 300 ° C under non-humidified or low humidity operating conditions of 50% or less. There is a demand for an electrolyte membrane that exhibits stable long-term conductivity. In the development of a conventional solid polymer electrolyte fuel cell, it has been studied in view of the above requirements, but perfluorocarbon sulfonic acid membranes have sufficient protons at an operating temperature of 100 ° C. to 300 ° C. and a relative humidity of 50% or less. There was a drawback that conductivity and output could not be obtained.

The following patent document discloses a solid electrolyte membrane made of polybenzimidazole doped with a strong acid such as phosphoric acid. According to this type of solid electrolyte membrane, it has excellent oxidation resistance and heat resistance, and can be operated even at a high temperature up to 200 ° C.
Japanese National Patent Publication No. 11-503262

  However, even in the solid electrolyte membrane made of polybenzimidazole doped with phosphoric acid, in order to obtain sufficient proton conductivity for fuel cell operation, 4-5 times as much phosphorus as polybenzimidazole weight can be obtained. Although it is necessary to contain an acid, such a membrane having a large phosphoric acid content has a problem of low mechanical strength and gas crossover when incorporated in a fuel cell.

  The present invention has been made in view of the above circumstances, and shows a gel electrolyte exhibiting high proton conductivity even under non-humidified and high temperature conditions and excellent in mechanical strength, and a fuel cell using this gel electrolyte. An object is to provide an electrode, a fuel cell, and a method for producing a gel electrolyte.

In order to achieve the above object, the present invention employs the following configuration.
The gel electrolyte of the present invention is characterized in that it contains at least an acid, a chain polymer that swells with respect to the acid, and a crosslinkable polymer complexed with the chain polymer.
Examples of the acid include phosphoric acid. The phosphoric acid includes both orthophosphoric acid and condensed phosphoric acid.

  According to the above configuration, since the chain polymer and the crosslinkable polymer are complexed, even when the chain polymer is swollen by an acid, the crosslinkable polymer is not swollen. A decrease in mechanical strength can be prevented.

  The gel electrolyte of the present invention is the gel electrolyte described above, wherein the crosslinkable polymer is crosslinked by electron beam irradiation.

  According to the above configuration, since the crosslinkable polymer is cross-linked by electron beam irradiation, it is unnecessary to add a polymerization initiator or a cross-linking agent that becomes impurities, and a decrease in proton conductivity due to these impurities is prevented. Can do.

  The gel electrolyte of the present invention is the gel electrolyte described above, wherein the chain polymer is polybenzimidazole or a polybenzimidazole derivative.

  According to said structure, many acids, such as phosphoric acid, can be impregnated with a chain polymer, and proton conductivity can be improved.

  The gel electrolyte of the present invention is the gel electrolyte described above, wherein the crosslinkable polymer is a fluorine-based polymer.

  According to the above configuration, since the fluoropolymer is thermally and chemically stable, the durability of the gel electrolyte can be enhanced. Further, the mechanical strength of the gel electrolyte can be improved.

  The gel electrolyte of the present invention is the gel electrolyte described above, and the content of the fluoropolymer relative to the total of the chain polymer and the fluoropolymer is 10% by mass or more and 40% by mass or less. It is characterized by that.

  According to said structure, since the content rate of a fluorine-type polymer is set to said range, improvement of mechanical strength and proton conductivity can be made compatible.

  Next, the electrode for a fuel cell of the present invention is characterized in that it contains at least an electrode material and the gel electrolyte described in any of the above.

  According to said structure, since the gel electrolyte excellent in proton conductivity is provided as a part of electrode, a proton becomes easy to be conducted to the inside of an electrode, and internal resistance of electrode itself can be reduced. Moreover, since gel electrolyte is excellent also in mechanical strength, durability of an electrode can be improved.

  The fuel cell of the present invention is composed of a pair of electrodes and an electrolyte membrane disposed between the electrodes, and a part or all of the electrolyte membrane is the gel electrolyte described in any of the above, In addition, the gel electrolyte is contained in a part of the electrode.

According to the above configuration, the gel electrolyte having excellent proton conductivity is provided as the gel electrolyte, and the gel electrolyte is also provided in a part of the electrode, so that the internal impedance of the fuel cell can be reduced, and the current density Can be increased.
Moreover, since gel electrolyte is excellent also in mechanical strength, durability of a fuel cell can be improved.

  Next, in the method for producing a gel electrolyte of the present invention, a chain polymer and an uncrosslinked crosslinkable polymer are mixed to form a sheet, and the electron beam is irradiated to the sheet to form the electron beam. The crosslinkable polymer is cross-linked by permeating from one side of the sheet to the other side, and then impregnated with an acid.

  According to the above configuration, since the electron beam is transmitted through the sheet containing the chain polymer and the crosslinkable polymer, a crosslinking reaction can be caused not only on the surface of the sheet but also inside thereof, and the chain is formed in the entire sheet. A gel electrolyte obtained by combining a glassy polymer and a crosslinkable polymer can be obtained.

  Moreover, the manufacturing method of the gel electrolyte of this invention is a manufacturing method of the gel electrolyte as described above, The acceleration voltage of the said electron beam shall be 1 MeV or more, It is characterized by the above-mentioned. With this configuration, a crosslinking reaction can be caused not only on the surface of the sheet but also inside.

In the method for producing a gel electrolyte of the present invention, the chain polymer is preferably polybenzimidazole or a polybenzimidazole derivative.
In the method for producing a gel electrolyte of the present invention, the crosslinkable polymer is preferably a fluoropolymer.

  Moreover, in the manufacturing method of the gel electrolyte of this invention, it is preferable that the content rate of the said fluoropolymer with respect to the sum total of the said chain polymer and the said fluoropolymer is 10 to 40 mass%.

  According to the gel electrolyte of the present invention, it is possible to exhibit high proton conductivity and excellent mechanical strength even under non-humidified and high temperature conditions.

  The fuel cell according to the present invention includes a hydrogen electrode (electrode), an oxygen electrode (electrode), and a gel electrolyte disposed between the hydrogen electrode and the oxygen electrode, and operates at a temperature of 100 ° C to 300 ° C. To do. The gel electrolyte according to the present invention has proton conductivity, and conducts protons (hydrogen ions) generated on the hydrogen electrode side to the oxygen electrode side. Protons conducted by the gel electrolyte electrochemically react with oxygen ions at the oxygen electrode to generate water and generate electrical energy.

  In the fuel cell according to the present invention, the hydrogen electrolyte and the oxygen electrode also contain a gel electrolyte. That is, the hydrogen electrode and the oxygen electrode contain an electrode material such as activated carbon and a binder for solidifying and forming the electrode material, and a part or all of this binder is the gel electrolyte according to the present invention. Yes. With this configuration, protons are easily conducted between the inside and outside of the electrode, and the internal resistance of the electrode is reduced.

  Next, the gel electrolyte according to the present invention contains at least an acid, a chain polymer that swells with respect to the acid, and a crosslinkable polymer complexed with the chain polymer. . Examples of the acid include phosphoric acid. The phosphoric acid includes both orthophosphoric acid and condensed phosphoric acid. The chain polymer is either polybenzimidazole or a polybenzimidazole derivative, and the crosslinkable polymer is a fluorine-based polymer. “Composite” refers to a state in which a chain polymer is mixed with a crosslinkable polymer and the chain polymer is incorporated into the crosslinkable structure of the crosslinkable polymer.

  The polybenzimidazole or polybenzimidazole derivative constituting the chain polymer is excellent in heat resistance and can be used as a fuel cell electrolyte because it can contain a large amount of phosphoric acid. As the value increases, the mechanical strength relatively decreases. In the present invention, polybenzimidazole or a polybenzimidazole derivative is combined with a two-dimensional or three-dimensionally crosslinked polymer (fluorine polymer), so that the mechanical strength of the gel electrolyte itself is reduced. Can be prevented. In addition, even when polybenzimidazole or polybenzimidazole derivatives are combined with a fluorine-based polymer, the molecular structure thereof does not change greatly, so that the phosphoric acid content does not decrease.

Polybenzimidazole constituting the gel electrolyte is a chain polymer having a structure shown in the following [Chemical Formula 1]. In the following [Chemical Formula 1], n ₁ is 10 to 100,000. If n ₁ is less than 10, the mechanical strength is lowered, which is not preferable. If n ₁ exceeds 100,000, the solubility in a solvent or the like is remarkably lowered, and it becomes difficult to form the gel electrolyte into a desired shape.

Examples of the polybenzimidazole derivative include partially methylated polybenzimidazole in which at least a part of the substituent R of the polybenzimidazole structure shown in the following [Chemical Formula 2] is a methyl group. In the following [Chemical Formula 2], R is CH ₃ or H, and n ₂ is 10 to 100,000. If n ₂ is less than 10, the mechanical strength is lowered, which is not preferable. If n ₂ exceeds 100,000, the solubility in a solvent or the like is remarkably lowered, and it becomes difficult to form the gel electrolyte into a desired shape. Partially methylated polybenzimidazole takes in more phosphoric acid and swells (gelates) as the degree of methylation increases. Thereby, proton conductivity can be further increased.

In addition, as said partially methylated polybenzimidazole, any of following (1)-(3) can be used.
(1) A polymethylated benzimidazole having a methylation rate adjusted to 5 mol% or more and less than 80 mol%, preferably 20 mol% or more and less than 80 mol%.
(2) A mixture of poly N methylbenzimidazole with a methylation rate of 100 mol% and polybenzimidazole with a methylation rate of 0 mol%, and the content of poly N methylbenzimidazole is 5 mol% or more and less than 80 mol% , Preferably 20 mol% or more and less than 80 mol%.
(3) A mixture of a polymethylated benzimidazole with a methylation rate of X mol% and a polybenzimidazole with a methylation rate of 0 mol%, where the weight of the polymethylated benzimidazole is A and the weight of the polybenzimidazole is B , F obtained by f (mol%) = AX / (A + B) is 5 mol% or more and less than 80 mol%, preferably 20 mol% or more and less than 80 mol%. However, said X is 80 mol% or more and less than 100 mol%.

According to the above (1) to (3), the methylation rate of the partially methylated polybenzimidazole can be 5 mol% or more and less than 80 mol%, preferably 20 mol% or more can be less than 80 mol%. . That is, in (1), the methylation rate can be adjusted by adjusting the degree of reaction for methylation. In (2), the methylation rate can be substantially adjusted by adjusting the content of poly-N methylbenzimidazole. Furthermore, in (3), the methylation rate can be substantially adjusted by adjusting the value of f.
When the methylation rate of the partially methylated polybenzimidazole is less than 5 mol%, phosphoric acid can be sufficiently taken in and proton conductivity becomes insufficient (because it decreases). When the conversion ratio is 80 mol% or more, phosphoric acid is excessively incorporated and the partially methylated polybenzimidazole is dissolved, which is not preferable.

  In the present specification, a part of the substituent R of the polybenzimidazole structure shown in the above [Chemical Formula 2] as a methyl group and the rest as hydrogen is called polymethylated benzimidazole. Moreover, what made all the substituent R of the polybenzimidazole structure shown in the above [Chemical Formula 2] a methyl group is called poly N methylbenzimidazole. Furthermore, what made all the substituents R of the polybenzimidazole structure shown in the above [Chemical Formula 2] hydrogen is called polybenzimidazole.

  Next, the crosslinkable polymer refers to a polymer having a two-dimensional or three-dimensional structure as generally indicated by a thermosetting resin or the like. In the present invention, a fluorine-based polymer can be used as the crosslinkable polymer. The fluorine-based polymer is suitable as an electrolyte for a fuel cell because it is thermally and chemically stable. Further, since the fluoropolymer does not swell with respect to phosphoric acid, the mechanical strength of the gel electrolyte can be improved.

  As a specific example of the fluorine-based polymer, a perfluoropolymer that is soluble in an organic solvent is preferable. For example, polyvinylidene fluoride, polyhexafluoropropylene, a copolymer of polyvinylidene fluoride and polyhexafluoropropylene, Nafion (registered trademark) ) And the like. These fluoropolymers are easily cross-linked by electron beam irradiation.

  The content of the crosslinkable polymer with respect to the total of the chain polymer and the crosslinkable polymer is preferably in the range of 10% by mass to 40% by mass, and more preferably in the range of 15% by mass to 25% by mass. If the content of the crosslinkable polymer is less than 10% by mass, the content of the chain polymer is relatively high, and the mechanical strength of the gel electrolyte is lowered. If it exceeds%, the content of the chain polymer is relatively lowered, the inclusion amount of phosphoric acid is lowered, and the proton conductivity is lowered.

  According to the gel electrolyte, since the chain polymer and the crosslinkable polymer are complexed, the crosslinkable polymer does not swell even when the chain polymer is swollen by an acid. A decrease in the mechanical strength of the electrolyte can be prevented.

  Next, the manufacturing method of the gel electrolyte of this embodiment is demonstrated. In this production method, a chain polymer and an uncrosslinked crosslinkable polymer are mixed, then irradiated with an electron beam to crosslink the crosslinkable polymer, and further impregnated with phosphoric acid.

  To mix a chain polymer and a crosslinkable polymer, prepare a solvent that can dissolve both the chain polymer and the crosslinkable polymer, and dissolve the chain polymer and the crosslinkable polymer in this solvent. The mixture is applied to a glass plate or the like by the doctor blade method or the like, and then the solvent is removed. Next, the coated film is immersed in water to swell and then dried. In this way, a sheet-like mixed resin sheet is obtained. As the solvent used here, for example, dimethylacetamide, N-methyl-2-pyrrolidinone and the like can be used. As the chain polymer, the above-described polybenzimidazole or polybenzimidazole derivative can be used. Further, as the crosslinkable polymer, the above-mentioned fluorine-based polymer can be used. The blending ratio of the chain polymer and the crosslinkable polymer is preferably such that the content of the crosslinkable polymer with respect to the total of the chain polymer and the crosslinkable polymer is 10% by mass or more and 40% by mass or less. More preferably, the content is 15% by mass or more and 25% by mass or less.

  Next, the mixed resin sheet is irradiated with an electron beam. The electron beam is irradiated by placing an electron gun on one side of the mixed resin sheet and irradiating the electron beam from the electron gun to transmit the electron beam from one side of the sheet to the other side. Whether or not the electron beam has passed through the sheet can be confirmed by placing a dosimeter in the vicinity of the sheet. By transmitting the electron beam in this way, the electron beam can be sufficiently irradiated inside the sheet. By irradiation with this electron beam, the uncrosslinked crosslinkable polymer contained in the sheet is crosslinked to form a crosslinked structure having a three-dimensional structure.

  The polybenzimidazole or polybenzimidazole derivative constituting the chain polymer has a rigid molecular structure as shown in the above [Chemical Formula 1] or the above [Chemical Formula 2], and therefore is irradiated with an electron beam. Even if it is, it hardly crosslinks. Thereby, even if an electron beam is irradiated, polybenzimidazole etc. hardly change, and the swelling property with respect to phosphoric acid does not change.

  The electron beam to be irradiated preferably has an acceleration voltage in the range of 1 MeV to 5 MeV, and more preferably in the range of 2 MeV to 3 MeV. The irradiation dose is preferably in the range of 20 kGy to 120 kGy, and more preferably in the range of 40 kGy to 80 kGy. If the acceleration voltage is less than 1 MeV, the electron beam cannot be transmitted through the sheet, which is not preferable. If the acceleration voltage exceeds 5 MeV, the irradiation apparatus is enlarged, which is not preferable for manufacturing. Further, if the irradiation dose is less than 20 kGy, the crosslinking reaction does not proceed sufficiently, which is not preferable. If the irradiation dose exceeds 120 kGy, the polymer is likely to collapse, which is not preferable.

  Next, the crosslinked polymer is directly immersed in phosphoric acid to swell the chain polymer. Thus, the gel electrolyte according to the present invention is obtained.

  According to the above production method, since the electron beam is transmitted through the sheet containing the chain polymer and the crosslinkable polymer, a crosslinking reaction can be caused not only on the surface of the sheet but also in the inside thereof. A gel electrolyte in which a chain polymer and a crosslinkable polymer are combined can be obtained.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to the content of this Example.
(Preparation of mixed resin sheet)
A solution was prepared by dissolving polybenzimidazole in dimethylacetamide to a concentration of 10% by mass. Separately, Nafion (registered trademark) as a fluoropolymer was sodium-treated by ion exchange and dried, and was similarly dissolved in dimethylacetamide to prepare a 10% by mass solution. Next, a polybenzimidazole solution and a Nafion (registered trademark) solution were mixed to obtain a mixed solution. At this time, the blending ratio of both solutions was adjusted so that the content of Nafion (registered trademark) with respect to the total of polybenzimidazole and Nafion (registered trademark) would be 0, 10, 20, 30, 40, 50% by mass. did.

  Next, the mixed solution was coated on a glass plate using a doctor blade, and once the coating surface became opaque, drying was performed once at 50 ° C. and further drying at 150 ° C. Next, the coating film was immersed in water together with the glass plate, and the swollen film was peeled off. Further, the membrane mixed with Nafion (registered trademark) was immersed in a large amount of 1 N sulfuric acid in a hot water bath at 60 ° C. for 24 hours for ion exchange. After ion exchange, the membrane was repeatedly washed with pure water, and then vacuum-dried at 6 ° C. and 0.1 torr. In this way, a mixed resin sheet was produced. The film thickness of the sheet was about 35 μm.

(Electron beam irradiation)
Each of the mixed resin sheets was sealed in an aluminum laminate film. Next, using an electron beam irradiation apparatus, an electron beam was irradiated at an acceleration voltage of 2 MeV so that an irradiation dose was 80 kGy.

(Immersion of phosphoric acid)
The mixed resin sheet after electron beam irradiation was directly immersed in 85% phosphoric acid preheated to 40 ° C. After 2 hours, the sheet was pulled up and the phosphoric acid on the sheet surface was wiped off with a wiping cloth. Thus, the gel electrolytes of Examples 1 to 4 and Comparative Examples 1 to 4 were produced. Table 1 shows the composition and the like of each gel electrolyte.

  For the gel electrolytes of Examples 1 to 4 and Comparative Examples 1 to 4, the swelling rate with respect to phosphoric acid, the solubility with respect to strong phosphoric acid, the tensile test, and the voltage drop when incorporated in a fuel cell were examined. The results are shown in Table 1 and FIG.

The swelling ratio with respect to phosphoric acid was determined from the weight of the gel electrolyte after immersing the gel electrolyte in phosphoric acid for 6 hours and the weight of the membrane without containing phosphoric acid by the following formula.
Swelling rate (%) = ((weight of gel electrolyte after swelling) / (dry weight of membrane before phosphoric acid swelling)) × 100

  The solubility in strong phosphoric acid was investigated by immersing the gel electrolyte in strong phosphoric acid at room temperature for 48 hours.

  In addition, the tensile test is performed by measuring a TMA curve by applying a tensile load from 40 to 1000 mN as a scanning speed of 100 mN / min in an isothermal dry nitrogen atmosphere at 30 ° C. using an EXSTAR6100TMA / SS manufactured by Seiko Denshi. went. The test piece was 3.5 mm wide × 20 mm long, the end point of the test piece was extended by 5 mm, and the elongation of the test piece relative to the load was observed.

  The voltage drop was applied to a carbon paper coated with self-supported carbon made by Electorochem by thinly applying the above mixed solution diluted 10 times, and then vacuum-dried to obtain an electrode. A test cell was produced by sandwiching the gel electrolyte between the two electrodes. Next, the test cell was sandwiched between carbon separators, and the open circuit voltage was measured using hydrogen as the anode gas and oxygen as the cathode gas. After confirming the open circuit voltage immediately after the assembly, the supply gas was kept flowing for 24 hours, and the potential difference decreased due to the crossover generated due to the breakage of the membrane was evaluated. The battery temperature was 150 ° C., and the supply gas was not particularly humidified.

  About the swelling rate with respect to the phosphoric acid of Examples 1-4, a weight change will each reach an equilibrium state when about 3 hours passed, and the equilibrium swelling rate measured when 6 hours passed is 400, 380, 370, 350, respectively. % (Table 1). On the other hand, about Comparative Examples 1-3, the swelling rate of 400% or more was shown. When Example 1 having a Nafion (registered trademark) content of 10% is compared with Comparative Example 3, there is no significant difference in the swelling rate. Thereby, the influence of the swelling rate by the presence or absence of electron beam irradiation seems to be small. Moreover, in Examples 1-4, it turns out that the swelling rate falls as the content rate of Nafion (trademark) increases.

  Moreover, about the solubility with respect to strong phosphoric acid of Examples 1-4, as shown in Table 1, each showed partial solubility, but insolubility becomes strong as the content rate of Nafion (registered trademark) increases. I understand. On the other hand, in Comparative Example 3 where no electron beam was irradiated, it can be seen that polybenzimidazole is completely dissolved in strong phosphoric acid.

Further, with respect to the tensile strength shown in FIG. 1, when Example 1 and Comparative Example 3 each containing 10% by mass of Nafion (registered trademark) are compared, there is a slight difference in elongation with respect to tensile load depending on the presence or absence of electron beam irradiation. Recognize.
Moreover, as shown in Examples 1 to 4 in FIG. 1, it can be seen that the elongation with respect to the tensile load decreases as the content of Nafion (registered trademark) increases.

  Thus, Examples 1-4 which irradiated the electron beam melt | dissolved partially with respect to strong phosphoric acid compared with the comparative example 3 which has not irradiated the electron beam, and the elongation with respect to a tensile load also becomes small. Therefore, it can be presumed that a cross-linked structure was formed by the cross-linking reaction and the mechanical strength was improved.

  Next, when the voltage drop of the gel electrolytes of Examples 1 to 4 was incorporated into a fuel cell and examined, as shown in Table 1, the open circuit voltage after 24 hours was significantly reduced as compared with the comparative example. I was not able to admit. Thereby, it turns out that the gel electrolyte of Examples 1-4 is excellent also in durability.

  Next, in Comparative Example 1, the degree of swelling with respect to phosphoric acid is as high as about 450%. However, as is apparent from FIG. 1, the mechanical strength is insufficient, so that in the test results incorporated in the fuel cell (Table 1), the decrease in the open circuit voltage after 24 hours has passed. It is large compared with 4, and it turns out that durability is inferior.

  Moreover, about the comparative example 2, it turns out that it melt | dissolves completely with respect to strong phosphoric acid. Thereby, even if it irradiates an electron beam to polybenzimidazole, it turns out that polybenzimidazole itself is not bridge | crosslinked. Other characteristics were almost the same as those of Comparative Example 1.

  Further, as shown in FIG. 1, it can be confirmed that the tensile strength of Comparative Example 3 is improved as compared with Comparative Example 1, but the tensile strength is low as described above compared with Example 1. confirmed.

  Further, in Comparative Example 4, since the content of the fluorine-based polymer is as large as 50% by mass, the film formability is very poor, and unevenness is observed on the surface even by visual observation, and thus a fuel cell that requires smoothness. It was impossible to use for the electrolyte.

The graph which shows the TMA curve of Examples 1-4 and Comparative Examples 1 and 3. FIG.

Claims (10)

And phosphoric acid, and the chain polymer to swell against the phosphoric acid, the chain-like polymer and Ri and decryption crosslinked polymer is Na is contained at least,
The crosslinkable polymer is a perfluorosulfonic acid polymer,
A gel electrolyte, wherein the chain polymer is polybenzimidazole or a polybenzimidazole derivative .   The gel electrolyte according to claim 1, wherein the crosslinkable polymer is crosslinked by electron beam irradiation. The crosslinkable polymer is one or more selected from the group consisting of polyvinylidene fluoride, polyhexafluoropropylene, a copolymer of polyvinylidene fluoride and polyhexafluoropropylene, and Nafion (registered trademark). The gel electrolyte according to claim 1 or 2 . According to any one of claims 1 to 3, wherein the content of the crosslinkable polymer to the total of the crosslinkable polymer and the chain polymer is not less than 10 wt% 40 wt% or less Gel electrolyte. An electrode for a fuel cell, comprising at least an electrode material and the gel electrolyte according to any one of claims 1 to 4 . It is comprised from a pair of electrode and the electrolyte membrane arrange | positioned between each electrode, A part or all of the said electrolyte membrane is made into the gel electrolyte in any one of Claims 1 thru | or 4 , and A fuel cell, wherein the gel electrolyte is contained in a part of the electrode. By mixing a chain polymer and an uncrosslinked crosslinkable polymer to form a sheet, irradiating the sheet with an electron beam and transmitting the electron beam from one side of the sheet to the other side A method for producing a gel electrolyte, wherein the crosslinkable polymer is crosslinked and then impregnated with phosphoric acid ,
The chain polymer is polybenzimidazole or a polybenzimidazole derivative;
A production method wherein the crosslinkable polymer is a perfluorosulfonic acid polymer. The method for producing a gel electrolyte according to claim 7 , wherein an acceleration voltage of the electron beam is 1 MeV or more. The crosslinkable polymer is one or more selected from the group consisting of polyvinylidene fluoride, polyhexafluoropropylene, a copolymer of polyvinylidene fluoride and polyhexafluoropropylene, and Nafion (registered trademark). A method for producing a gel electrolyte according to claim 7 or 8 . 10. The content of the crosslinkable polymer with respect to the total of the chain polymer and the crosslinkable polymer is 10% by mass or more and 40% by mass or less, according to claim 7. A method for producing a gel electrolyte.

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