KR101367558B1 - Polymer membranes for fuel cells, based on interpolyelectrolyte complexes of polyaniline and nafion or it's analogues - Google Patents

Abstract

The present invention is a formulation comprising an interpolyelectrolyte complex containing emeraldine polyaniline and Nafion (manufactured by Dupont) or MF-4SK (manufactured by JSC Plastpolymer, St. Petersburg, Russia) or an analog thereof A polymer membrane for fuel cells based on The membrane material is prepared by casting a solution of the interpolyelctrolyte complex in the form of a solvent mixture. The membrane thus prepared may be further treated with organic sulfonic acid or inorganic additives to add protons to the polyaniline and additionally attach sulfo groups, thereby increasing the proton conductivity of the membrane. The proton conductivity of the membrane thus prepared exceeds the proton conductivity of untreated Nafion or MF-4SK or other Nafion-like polymers, has better durability, and does not fail at 90 ° C., therefore, at higher temperatures than Nafion or its analogs. Work, more stable. The present invention provides a process for producing a polymer membrane based on the interpolyelctrolyte composite for use in low temperature or high temperature polymer fuel cells.

Description

POLYMER MEMBRANES FOR FUEL CELLS, BASED ON INTERPOLYELECTROLYTE COMPLEXES OF POLYANILINE AND NAFION OR IT'S ANALOGUES}

       The present invention relates to polymer membranes for fuel cells based on interpolyelctrolyte composites of polyaniline and Nafion or analogs thereof.

Currently, the most widely used electrolyte membrane is a perfluorinated sulfonic acid series electrolyte membrane known as Nafion (manufactured by DuPont). Nafion has a side chain attached to the main chain of hydrophobic polytetrafluoroethylene (PTFE), which side chain has sulfonic acid groups at its ends. Sulfonate groups and hydrated water molecules combine to form ion clusters. Because of the high concentration of sulfone groups in the cluster, the cluster becomes a proton pathway with high proton conductivity.

Other electrolyte membranes other than Nafion include hydrocarbon electrolyte membranes and aromatic hydrocarbon electrolyte membranes. Both of these membranes have proton donors such as sulfonic acid groups, phosphoric acid groups, carboxylic acid groups and the like. Like Nafion, these electrolyte membranes exhibit proton conductivity by freeing protons when hydrated. In the case of Nafion, increasing the amount of proton donors, such as sulfonic acid groups, increases proton conductivity due to increased water consumption by sulfonic acid hydration and the generation of continuous hydrogen bonding networks in the membrane channels and cluster systems.

Nevertheless, the reduction in the proton conductivity of Nafion occurring at 90 ° C. limits the use of the membrane above 100 ° C. Another negative factor of Nafion is the water expandability of Nafion, which reduces the mechanical durability of the membrane. Malfunction of Nafion at low humidity is also a limiting factor in the use of Nafion membranes in certain applications.

Accordingly, the present invention seeks to provide a proton conductive polymer membrane having improved proton conductivity, improved durability, low water absorption and low water expandability than untreated Nafion.

      The present invention is not limited to Nafion and polyaniline, or MF-4SK (Russian Nafion analogue) and Polyaniline, or Nafion, and is not limited to Flemion, Aciplex, Dowmembrane, Neocepta ( Neosepta), MF-4SK, and proton conductivity based on polymer electrolyte composites of other ion exchange resins containing carboxylic acid groups and sulfonic acid groups and having improved proton conductivity, improved durability, low water absorption and low water expandability than untreated Nafion. Provide a polymer membrane.

Mixture of

(a) As the monomer for polymerization, not only aniline or aniline dihydrosulfate, but acid addition salts such as aniline hydrochloride, aniline hydrofluoric acid, aniline trihydrophosphate, aniline bromide and aniline iodide,

(b) Ammonium peroxydisulfate, sodium persulfate, sodium periodate, potassium dichromate, potassium permanganate, potassium hypobromide, potassium hypochloride, cerium nitrate, cerium sulfate, hydrogen peroxide, iron (III) chloride, sulfuric acid Iron (III), Fenton's reagent (a mixture of hydrogen peroxide and divalent iron) and other compounds not limited to the above, or combinations thereof, wherein the [oxidant / aniline] ratio is 0.1 to 5, more preferably 0.5 to 2, and most preferred Preferably 1 to 1.5,

(c) MF-4SK or Nafion or other Nafion-like polymers in a positive form with sulfone functionality and at least greater than 1, wherein the [aniline / nafion or Nafion-like polymer] ratio is 0.001 to 3,

(d) alcohols such as methanol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, ethers such as diethyl ether, dipropyl ether, dibutyl ether, methyl Asymmetric ethers such as ethyl ether, ethyl propyl ether, lactones, lactams, ketones, esters, formamides, dimethyl sulfoxide, tetrahydrofuran, acetonitrile and other solvents or mixtures thereof and other distilled water [water Mixture of] / [alcohol] ratios

Liquid formulations are prepared from mixtures comprising:

The liquid formulation is cast on a horizontal plane and dried in air to form a polymer film.

In another embodiment, the present invention relates to the proton conducting polymer membrane adjustment needed to reach full hydration and can be done as follows:

a) aqueous solutions of sulfuric acid, hydrochloric acid, phosphoric acid, formic acid, acetic acid, or hydrogen peroxide (preferably between 0.5 and 50% solutions, more preferably between 1 and 20% solutions and most) Preferably 5-10% solution). The conditioning is carried out at 100 ° C. for 30 minutes to 6 hours, more preferably 1 hour to 5 hours, and most preferably 2 hours to 4 hours.

b) Membrane adjusted in deionized distilled water at 100 ° C. for 30 minutes to 6 hours, more preferably 1 hour to 5 hours, and most preferably 2 hours to 4 hours.

In another embodiment, the invention is not limited to organic thiols themselves, mercaptobenzenesulfonic acid, mercaptoethanol, mercaptopropanol, mercaptobutanol, mercaptopentanol, mercaptohexanol, mercaptoethansulfonic acid, mercury Further improve the proton conductivity of the membrane by doping polyaniline with captopropanesulfonic acid, mercaptobutanesulfonic acid, mercaptopentanesulfonic acid, mercaptohexanesulfonic acid, mercaptoacetic acid, mercaptopropionic acid, mercaptobutyric acid, mercaptopentanoic acid, mercaptohexane, etc. It's about making things happen. These thiols act as electrophiles that allow electrophilic addition of polyaniline to the quinonediimine ring, which is included in the interpolyelctrolyte complex of Nafion or its analogs. This reaction can be carried out in an alkaline solution containing polyaniline and a raw membrane prepared from a solution of Nafion or polyelectrolyte complex, for example, and an excess of thiol in an inert atmosphere and at room temperature. Excess thiol should be 2 to 2000 times, preferably 10 to 1000 times, and most preferably 50 to 500 times. Then adjustment of the thiol treated membrane is necessary.

In another embodiment the invention is not limited to other reducing agents per se, hydrazine hydrates, phenyl hydrazine, sodium borohydride, hydrazine borane, ascorbic acid, sodium thiosulfate, alkali metals such as lithium, sodium, potassium, cesium, alkaline earth metals For example, the present invention relates to doping polyaniline with calcium, magnesium and the like to further improve the proton conductivity of the membrane. The reducing agent increases the proton mobility inside the membrane by reducing the polyaniline quinonediimine ring to the p-phenylenediamine ring and reducing the amount of electrostatic bond between the Nafion-like polymer and polyaniline. Such modifications are not limited to reducing agent solutions having a reducing agent concentration of 0.001 to 10 M, more preferably 0.01 to 5 M, and most preferably 0.1 to 1 M, or water, but are not limited to aliphatic alcohols such as methanol, ethanol, propanol, butanol, Not limited to pentanol, hexanol and isomers thereof, ethers such as diethyl ether, but not limited to dipropyl ether, dibutyl ether and asymmetric ethers such as methylethyl ether, such as ethylpropyl ether, lactones, lactams, It may be carried out in a reducing agent dispersion in a suitable solvent including ketones, esters, formamides, dimethylsulfoxides, tetrahydrofuran, acetonitrile and the like. The reduction reaction can be carried out by immersing the raw membrane in a reducing agent suspension solution in a suitable solvent or by adding a reducing agent solution or suspension to a polymer electrolyte complex solution in a suitable solution. The reduced composite is then cast onto a plane and the obtained or treated dry membrane is adjusted as above.

Membranes prepared as described above exhibit 10 times higher proton conductivity than untreated Nafion, do not fail at 90 ° C., and are more durable and suitable for use in low to low temperature polymer membrane fuel cells (PMFC).

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are for the purpose of illustrating the present invention and are not intended to limit the scope of the present invention by the following examples.

Example 1 Preparation of Polyaniline-MF-4SK Composite Membrane

Aniline hydrochloride dissolved in the solvent mixture for preparation of the liquid formulation was mixed with MF-4SK suspended in the solvent mixture and stirred for 30 minutes for homogenization ([Aniline hydrochloride] / [MF-4SK] = 0.01-1.5). The ammonium peroxydisulfate solution dissolved in the solvent mixture was then added immediately to the mixture of aniline hydrochloride and MF-4SK ([ammonium peroxydisulfate] / [aniline hydrochloride] = 1.25), and the reaction mixture was stirred briefly and then at room temperature overnight. It was left to polymerize. The homogeneous solution of the obtained polyaniline and interpolyelctrolyte complex composed of MF-4SK was cast on a polyethylene membrane developed on a flat or glass ring of a petri cap and dried at room temperature to obtain a proton conductive membrane. . The membrane was then separated from the surface and preconditioned for 3 hours in boiling 1M HCl and 3 hours in boiling distilled water.

Example 2 Modification of Polyaniline-MF-4SK Composite Membrane Using Mercaptopropanesulfonic Acid

The polyaniline-MF-4SK membrane having a ratio of [Aniline hydrochloride] / [MF-4SK] = 0.01-1.5 in the initial mixture was placed in a glass vial containing 1M NaOH aqueous solution and immersed within 1 hour. Argon was then blown into the 1M NaOH solution containing the submerged polyaniline-MF-4SK membrane for 10 minutes. A 100-fold excess of mercaptopropanesulfonic acid (calculated based on polyaniline monomer units) was then dissolved in 1 M NaOH, blown with argon and immediately added to the balance of NaOH solution containing polyaniline-MF-4SK membrane. The reaction system was left for 1 week in a closed vial. All membranes were then washed with deionized water and adjusted as in Example 1.

Example 3 Treatment of Polyaniline-MF-4SK Composite Membrane Using Reducing Agent (NaBH ₄ )

Polyaniline-MF-4SK membrane having a ratio of [Aniline hydrochloride] / [MF-4SK] = 0.01-1.5 in the initial mixture was added with 1M NaBH ₄ It was put in a glass vial containing an aqueous solution and immersed within 1 hour. All membranes were then washed with deionized water and adjusted as in Example 1.

Suspension formulations of interpolyelctrolyte complexes comprising such polyaniline and Nafion or analogs thereof have formed membranes with good mechanical properties. These membranes have proton conductivity 10 times higher than Nafion's proton conductivity at room temperature and high water absorption even at elevated temperatures. And no decrease in proton conductivity at 100 ° C. In addition, these membranes expand less in water and can be used as proton conducting membranes (PMFC) for low and low temperature fuel cells.

Claims (12)

A proton conductive polymer membrane that is a cast of a polymer electrolyte composite of polyaniline and Nafion, wherein the molar ratio of polyaniline to Nafion is in the range of 0.001 to 3, methanol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol , n-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, diethyl ether, dipropyl ether, dibutyl ether, methylethyl ether, ethylpropyl ether, lactone, lactam, ketone, ester, formamide, dimethyl sulfoxide, Oxidizing agent or ammonium peroxydisulfate, sodium persulfate, sodium periodide, potassium dichromate, permanganic acid in a mixture of one or more solvents selected from tetrahydrofuran, acetonitrile and mixtures thereof and other [water / alcohol] ratios of distilled water Potassium, potassium hypobromide, potassium hypochloride, cerium nitrate, cerium sulfate, hydrogen peroxide, iron chloride (III ), Using an oxidant mixture selected from iron (III) sulfate and Fenton's reagent (a mixture of hydrogen peroxide and ferric iron),
The proton conductive polymer membrane may include mercaptobenzenesulfonic acid, mercaptoethanol, mercaptopropanol, mercaptobutanol, mercaptopentanol, mercaptohexanol, mercaptoethanesulfonic acid, mercaptopropanesulfonic acid, mercaptobutanesulfonic acid, mercaptopentane Additionally doped with an organic thiol selected from sulfonic acid, mercaptohexanesulfonic acid, mercaptoacetic acid, mercaptopropionic acid, mercaptobutyric acid, mercaptopentanoic acid and mercaptohexane, or
The proton conductive polymer membrane is further doped with a reducing agent itself selected from hydrazine hydrate, phenyl hydrazine, sodium borohydride, hydrazine borane, ascorbic acid, sodium thiosulfate, lithium, sodium, potassium, cesium, calcium, magnesium Conductive polymer membrane. Of polyaniline and MF-4SK (Russian Nafion analogue) or Flemion, Aciplex, Dowmembrane, Neosepta, and other ion exchange resins containing carboxylic and sulfonic acid groups A proton conductive polymer membrane based on a polymer electrolyte composite, wherein the ratio of polyaniline to MF-4SK is in the range of 0.001 to 3, and methanol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl Alcohols, tert-butyl alcohol, diethyl ether, dipropyl ether, dibutyl ether, methylethyl ether, ethylpropyl ether, lactones, lactams, ketones, esters, formamide, dimethylsulfoxide, tetrahydrofuran and acetonitrile or their Formed in a mixture of different [water / alcohol] ratios of solvent and distilled water selected from the mixture,
The proton conductive polymer membrane may include mercaptobenzenesulfonic acid, mercaptoethanol, mercaptopropanol, mercaptobutanol, mercaptopentanol, mercaptohexanol, mercaptoethanesulfonic acid, mercaptopropanesulfonic acid, mercaptobutanesulfonic acid, mercaptopentane Additionally doped with an organic thiol selected from sulfonic acid, mercaptohexanesulfonic acid, mercaptoacetic acid, mercaptopropionic acid, mercaptobutyric acid, mercaptopentanoic acid and mercaptohexane, or
The proton conductive polymer membrane is further doped with a reducing agent itself selected from hydrazine hydrate, phenyl hydrazine, sodium borohydride, hydrazine borane, ascorbic acid, sodium thiosulfate, lithium, sodium, potassium, cesium, calcium, magnesium Conductive polymer membrane. The proton conductive polymer membrane of claim 1 or 2, wherein the proton conductive polymer membrane is adjusted at 100 DEG C for 30 minutes to 6 hours in an acid selected from nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, formic acid and acetic acid, or aqueous hydrogen peroxide solution. Polymer membrane. The method according to claim 1 or 2, wherein the proton conductive polymer membrane is adjusted at 100 DEG C for 30 minutes to 6 hours in an acid selected from 1M nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, formic acid and acetic acid, and then 30 minutes to deionized distilled water. A proton conductive polymer membrane, further adjusted at 100 ° C. for 6 hours. The reaction of claim 1 or 2, wherein the reaction further doped with the organic thiol itself contains a composite solution comprising a raw membrane and a thiol prepared from polyaniline and Nafion or a polymer electrolyte composite solution in an inert atmosphere and at room temperature. A proton conductive polymer membrane, characterized in that it is carried out in an alkaline solution. The method of claim 1 or 2, wherein the reforming further doped with the reducing agent itself is a reducing agent solution having a reducing agent concentration of 0.001 to 10 M concentration or water, methanol, ethanol, propanol, butanol, pentanol, hexanol and isomers thereof, diethyl In a reducing agent dispersion in a solvent selected from ether, dipropyl ether, dibutyl ether, methylethyl ether, ethylpropyl ether, lactone, lactam, ketone, ester, formamide, dimethyl sulfoxide, tetrahydrofuran and acetonitrile, The reduction reaction is performed by immersing a raw membrane in a reducing agent suspension or adding a reducing agent solution or suspension to a polymer electrolyte composite solution. delete delete  A method for producing a polymer membrane for low temperature fuel cell, comprising using a doped proton conductive polymer membrane according to claim 1. The polymer of claim 9, wherein the proton conductive polymer membrane is adjusted at 100 ° C. for 30 minutes to 6 hours in an acid selected from nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, formic acid, acetic acid, or aqueous hydrogen peroxide solution. Method of Making Membranes. The method according to claim 9, wherein the reaction further doped with the organic thiol itself is carried out in an inert atmosphere and at room temperature in an alkaline solution containing a composite solution comprising a thiol and a raw membrane prepared from a polyaniline and a polymer electrolyte composite solution,
Method of producing a polymer membrane for low-temperature fuel cell, characterized in that after the doping is adjusted at 100 ℃ for 30 minutes to 6 hours in an acid selected from nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, formic acid and acetic acid, or aqueous hydrogen peroxide solution. 10. The method of claim 9, wherein the further doping with the reducing agent itself is a reducing agent solution having a reducing agent concentration of 0.001 to 10 M or water, methanol, ethanol, propanol, butanol, pentanol, hexanol and its isomers, diethyl ether, di The reduction reaction is carried out in a reducing agent dispersion in a solvent selected from propyl ether, dibutyl ether, methylethyl ether, ethylpropyl ether, lactone, lactam, ketone, ester, formamide, dimethylsulfoxide, tetrahydrofuran and acetonitrile. By dipping the raw membrane in the silver reducing agent suspension or by adding the reducing agent solution or suspension to the polymer electrolyte complex solution,
Method of producing a polymer membrane for low-temperature fuel cell, characterized in that after the doping is adjusted at 100 ℃ for 30 minutes to 6 hours in an acid selected from nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, formic acid and acetic acid, or aqueous hydrogen peroxide solution.