KR100843569B1 - Proton conductive composite triblock polymer electrolyte membrane and preparation method thereof - Google Patents

Abstract

A proton conductive composite triblock copolymer electrolyte membrane is provided to realize excellent thermal, mechanical and chemical stability, high ion conductivity, low methanol crossover, dehydration and gas permeability, and improved structural stability. A proton conductive composite triblock copolymer electrolyte membrane comprises 40-90 wt% of a triblock copolymer having a hydrophobic block, hydrophilic block and ion conductive block and represented by the following formula 1, and 10-60 wt% of an inorganic ion conductor, based on the total polymer electrolyte membrane. In formula 1, R1 is H or CH3; R2 is C6H6, C6H5-CnH2n+1, CnH2n+1, O-CnH2n+1 or COO-CnH2n+1; R3 is OH, C6H5OH, COO(CH2)n-OH or CONH(CH2)n-OH; R4 is C6H5-SO3^-, (CH2)n-SO3^- or COO(CH2)n-SO3^- ; each n is an integer; each of x, y and z is 100-10,000; and b represents a block.

Description

Proton Conductive Composite Triblock Polymer Electrolyte Membrane and Preparation Method Thereof}

1 is a flow chart showing a method for producing a hydrogen ion conductive composite triblock copolymer electrolyte membrane according to the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrogen ion conductive composite triblock copolymer electrolyte membrane and a method of manufacturing the same, and more particularly, to mixing a triblock copolymer made of a hydrophobic block, a hydrophilic block, and an ion conductive block with an inorganic ion conductor. It relates to a hydrogen ion conductive composite triblock copolymer electrolyte membrane prepared by the same and a method for producing the same.

A polymer electrolyte membrane commonly used to date is a perfluorosulfonic acid-based ion exchange membrane having a sulfonic acid group (-SO ₃ H), and the chemical structure of the membrane is represented by Structural Formula 1 below.

Herein, the ratio of x and y in Structural Formula 1 is 20: 1 to 2: 1, and m = 0, 1, or 2, n = 1 to 12.

Such ion exchange membranes having Structural Formula 1 include a Nafion membrane from Du Pont, a Dow Chemical membrane from Dow Chemical, a Flemion membrane from Asahi Glass, and Asahi Chemical. Asahi Chemical's Aciplex membrane, Ballard's Bam membrane, Gore's Premier membrane and the like are mainly used.

 The electrolyte membranes of the above-mentioned perfluorinated sulfonic acid series are well received for their high ionic conductivity and excellent mechanical and chemical stability, but they are high in price, rapidly decrease in hydrogen ion conductivity at temperatures above 100 ° C, and high methanol crossover. There is a problem.

Therefore, the current market demands an electrolyte membrane, particularly an electrolyte membrane used in a polymer electrolyte fuel cell, in which a manufacturing process is simple, low cost, high hydrogen ion conductivity, and an electrolyte membrane having excellent mechanical and chemical properties.

On the other hand, a conventional method for producing a polymer electrolyte membrane is a method of introducing a sulfonic acid group through a sulfonation reaction to a polymer containing a benzene group, which is the acidity of the sulfonic acid group is generally a fluorosulfonic acid group of Nafion Since it is much lower, it is necessary to reach an extremely high sulfonation degree to obtain satisfactory conductivity of the electrolyte membrane. However, when the sulfonation degree is very high, there is a problem that the mechanical strength and solubility of the polymer membrane is not good.

Accordingly, as a method for obtaining high ionic conductivity while maintaining the mechanical strength of the polymer electrolyte membrane, International Patent Application Publication No. WO 2004/042839 discloses ionic and nonionic polymers composed of block copolymers, and Korean Patent Publication No. 2003-0038232. No. discloses an ion exchange membrane in the form of a film in which a copolymer comprising a structural unit capable of causing a crosslinking reaction and a structural unit substituted by an ion conductive group is crosslinked with each other.

In particular, the ion exchange membrane according to the Republic of Korea Patent Publication No. 2003-0038232 constitutes an ion exchange membrane, that is, an electrolyte membrane in which a copolymer including a structural unit capable of causing a crosslinking reaction and a structural unit substituted by an ion conductive group is crosslinked with each other. By doing so, the conductivity of hydrogen ions is less affected by moisture and methanol, and the methanol crossover can be solved, which can be used in various electrochemical devices including fuel cells.

On the other hand, in order to solve the methanol crossover problem of the polymer electrolyte membrane and to improve the humidification effect and the mechanical strength, a study on the polymer electrolyte membrane using an inorganic ion conductor has recently been conducted, and Korean Patent Publication No. 2003-0032321 A method of using phosphotungstic acid (P ₂ O ₅ · 24 WO ₃ · H ₂ O, phosphotungstic acid) as a polymer electrolyte membrane for fuel cells having excellent ion conductivity even at a high temperature of 120 ° C. or higher is disclosed.

Here, the phosphorus tungstic acid is a water-soluble particle having a hydrogen ion conductivity of 0.12 S / cm or more at room temperature, and when added to a perfluorosulfonic acid electrolyte membrane in which resistance increase occurs at low humidity conditions, the water retention property of the electrolyte is improved to increase the moisture retention. The output of the polymer electrolyte fuel cell may be increased, and in addition to phosphorus tungstic acid, heteropolyacids such as silicon tungstic acid and phosphormolybdic acid may be used as the additive.

However, these heteropolyacid compounds are highly water soluble and are dissolved by moisture generated during operation of the fuel cell, so that fine pores are formed in the polymer electrolyte membrane, thereby causing a problem of intensifying the methanol crossover phenomenon of the electrolyte membrane.

The present invention has been made to solve the above problems, and has thermal, mechanical and chemical stability, high ion conductivity, low fuel (eg methanol) permeability, low dehydration effect, low gas permeability, and electrical conductivity There is a technical problem to provide a polymer electrolyte membrane, preferably a hydrogen ion conductive composite triblock copolymer electrolyte membrane, which is substantially free, has structural stability, and is not easily broken even when dried or expanded.

The present invention also provides a hydrogen ion conductive composite triblock copolymer electrolyte membrane that can be used in DMFC (Direct Methanol Fuel Cell), which is a fuel cell using methanol as a fuel.

In addition, the present invention converts the existing multi-stage synthesis process for producing a polymer electrolyte membrane into a single manufacturing process to reduce the production cost, shorten the manufacturing time to commercialize fuel cells such as PEMFC (polymer electrolyte membrane fuel cell) or DMFC There is a technical problem to provide a hydrogen ion conductive composite triblock copolymer electrolyte membrane and a method for producing the same that can contribute to.

In one aspect, the present invention is 40 to 90% by weight of the triblock copolymer comprising a hydrophobic block, a hydrophilic block and an ion conductive block represented by the formula 1 based on the total weight of the polymer electrolyte membrane and 10 to 60% by weight of the inorganic ion conductor It provides a hydrogen ion conductive composite triblock copolymer electrolyte membrane containing%.

------ (화학식 1)

------ (Formula 1)

,

, C_nH_2n+1, O-C_nH_2n+1, COO-C_nH_2n+1이고; R₃은 OH,

, COO(CH₂)_n-OH, CONH(CH₂)_n-OH이고; R₄는

, (CH₂)_n-SO₃ ^-, COO(CH₂)_n-SO₃ ^- 이고(상기 모든 n은 정수임); x, y 및 z는 각각 100 내지 10,000이고; b는 블록이다.Wherein R ₁ is H or CH ₃ ; R ₂ is

,

, C _n H _{2n + 1} , OC _n H _{2n + 1} , COO-C _n H _{2n + 1} ; R ₃ is OH,

, COO (CH ₂ ) _n -OH, CONH (CH ₂ ) _n -OH; R ₄ is

_{, (CH 2) n -SO 3} -, COO (CH 2) n -SO 3 - , and (wherein n is any integer); x, y and z are each 100 to 10,000; b is a block.

In this case, b is a symbol representing a block copolymer.

In addition, the molecular weight of the hydrogen ion conductive composite triblock copolymer electrolyte membrane is 10,000 to 1,000,000 Da.

In another aspect, the present invention provides a fuel cell including the hydrogen ion conductive composite triblock copolymer electrolyte membrane.

In another aspect, the present invention provides a method for preparing a hydrophobic monopolymer, comprising: i) polymerizing a hydrophobic monomer to prepare a hydrophobic homopolymer composed of a polymer polymer containing 10 to 30 wt% of hydrophobic groups based on the total triblock copolymer weight; Ii) a hydrophobic-hydrophilic diblock copolymer is prepared by mixing a polymer polymer comprising 10 to 30% by weight of hydrophilic groups based on the total weight of the triblock copolymer prepared by polymerizing the hydrophobic single polymer and the hydrophilic monomer of step iii). Manufacturing step; Iii) hydrophobicity by mixing a hydrophobic-hydrophilic diblock copolymer of step ii) with a polymer polymer containing 40 to 80% by weight of an ion conductive group based on the total triblock copolymer weight prepared by polymerizing an ion conductive monomer. Preparing a hydrophilic-ion conductive triblock copolymer; Iii) 40 to 90% by weight of the hydrophobic-hydrophilic-ion conductive triblock copolymer and 10 to 60% by weight of the inorganic ion conductor based on the total weight of the polymer electrolyte membrane, based on the total weight of the polymer electrolyte membrane. Mixing with a solvent to prepare a triblock copolymer and an inorganic ion conductor solution; And iii) a solution casting step of molding the triblock copolymer and inorganic ion conductor solution of step iv) into an electrolyte membrane form. Iii) providing a method for producing a hydrogen ion conductive composite triblock copolymer electrolyte membrane comprising a solvent drying step of removing the solvent by drying at a temperature of 20 to 150 ℃ for 6 to 48 hours after the step iii) is completed.

The polymer electrolyte membrane according to the present invention is a member material existing between the negative electrode (fuel electrode) and the positive electrode (air electrode) inside the fuel cell constituting the power generation unit of the fuel cell, and hydrogen gas on the negative electrode side does not pass, and the proton (ionized) Only hydrogen) is responsible for conducting from the negative electrode side toward the positive electrode side, and means a hydrogen ion conductive composite triblock copolymer in the present invention.

In particular, the hydrogen ion conductive composite triblock copolymer electrolyte membrane according to the present invention has thermal, mechanical and chemical stability, has high ion conductivity, low fuel (eg methanol) permeability, low dehydration effect and gas permeability, and electrical conductivity Is substantially (10 ^-12 S / cm or less), structurally stable and does not break easily when dried or expanded.

Here, the fuel cell converts chemical energy generated by the oxidation of the fuel directly into electrical energy, and is not particularly limited as long as it is a conventional fuel cell in the art used for this purpose, but preferably PEMF (polymer electrolyte membrane fuel) cell) or DMFC (Direct Methanol Fuel Cell).

Furthermore, the hydrogen-ion conductive composite triblock copolymer electrolyte membrane according to the present invention can be electro / chemically required for electrolyte membranes such as electrolysis, electrodialysis, diffusion dialysis, pressure dialysis, chloro-alkali separators and / or batteries. It can also be used for phosphorus devices.

On the other hand, the hydrogen ion conductive composite triblock copolymer electrolyte membrane according to the present invention is a triblock copolymer represented by the formula (1), preferably a triblock copolymer consisting of a hydrophobic block, a hydrophilic block and an ion conductive block and an inorganic ion conductor and It can be prepared by mixing, preferably the step of preparing a triblock copolymer, for example a triblock copolymer consisting of a hydrophobic block, a hydrophilic block, an ion conductive block and the prepared triblock copolymer and an inorganic ion conductor May be classified into a step of preparing an electrolyte membrane by mixing with each other.

Here, the method for producing a triblock copolymer, preferably a triblock copolymer composed of a hydrophobic block, a hydrophilic block and an ion conductive block, is particularly limited as long as it is a conventional method in the art for producing a triblock copolymer. Although not preferably, it comprises a polymer production reaction having a uniform molecular weight, while removing substances such as undesired homopolymers and chain breakdown products, preferably through controlled free radical polymerization.

At this time, the controlled free radical polymerization reaction may be any polymerization reaction that is conventionally controlled free radical polymerization reaction in the art, but preferably, atomic transfer radical polymerization (ATRP), nitroxide transfer Nitride-mediated polymerization (NMP), reversible addition-fragmentation chain transfer (RAFT), anionic polymerization or cationic polymerization are recommended. .

Meanwhile, the triblock copolymer composed of the hydrophobic block, the hydrophilic block and the ion conductive block according to the present invention may be referred to as a hydrophobic-hydrophilic-ion conductive triblock copolymer for easy explanation of the present invention.

Thus, the triblock copolymer according to the present invention, preferably a method for producing a triblock copolymer consisting of a hydrophobic block, a hydrophilic block and an ion conductive block represented by the formula (1) will be described in more detail.

First, iii) polymerizing the hydrophobic monomer to prepare a hydrophobic homopolymer composed of a polymer polymer containing 10 to 30% by weight of hydrophobic groups based on the total triblock copolymer weight;

Ii) preparing a hydrophobic-hydrophilic diblock copolymer by mixing a polymer polymer containing 10 to 30% by weight of hydrophilic groups based on the total weight of the polymer electrolyte membrane prepared by polymerizing the hydrophobic single polymer and the hydrophilic monomer of step iii). Doing;

Iii) hydrophobic-hydrophilic by mixing a hydrophobic-hydrophilic diblock copolymer of step ii) with a polymer polymer containing 40 to 80% by weight of ion conductive groups based on the total polymer electrolyte membrane weight prepared by polymerizing the ion conductive monomer -Preparing an ion conductive triblock copolymer.

,

,

,

,

,

,

등으로부터 중합된 고분자를 사용하는 것이 좋다. 이때, 상기 소수성 단량체의 R은 C_nH_2n+1(여기서, n은 정수임) 또는

이다.Here, the polymer containing the hydrophobic group is to provide a hydrophobic block of the triblock copolymer according to the present invention, preferably a triblock copolymer consisting of a hydrophobic block, a hydrophilic block and an ion conductive block, Any polymer may be used as long as it is a polymer containing, but is preferably a monomer for forming a hydrophobic block, that is, a hydrophobic monomer, for example

,

,

,

,

,

,

It is preferable to use a polymer polymerized from the like. Wherein R in the hydrophobic monomer is C _n H _{2n + 1} (where n is an integer) or

to be.

In addition, representative materials that can be used as the polymer containing the hydrophobic group described above include polystyrene, polyalkylstyrene, polymethacrylate, polyacrylate, polyisoprene, polybutadiene, polyacrylamide, polyvinyl ether or mixtures thereof. It is preferable to use a copolymer including the amount thereof, and the amount of use may be 10 to 30% by weight based on the total weight of the triblock copolymer.

,

,

,

,

등으로부터 중합된 고분자를 사용하는 것이 좋다.The polymer comprising a hydrophilic group according to the present invention is to provide a hydrophilic block of a triblock copolymer according to the present invention, preferably a triblock copolymer composed of a hydrophobic block, a hydrophilic block and an ion conductive block. Any polymer may be used as long as it is a polymer polymer capable of interacting with a conductor, preferably a polymer polymer including a hydrophilic group, but preferably a monomer for forming a hydrophilic block, that is, a hydrophilic monomer, for example

,

,

,

,

It is preferable to use a polymer polymerized from the like.

Representative materials that can be used as the polymer containing the hydrophilic group described above include polyhydroxy methacrylate, polyhydroxy acrylate, polyhydroxy methacrylamide, polyhydroxy acrylamide, polyvinylphenol, polyvinyl It is preferable to use a copolymer comprising alcohol, polyethylene glycol, polypropylene glycol or mixtures thereof, and the amount of the copolymer is preferably 10 to 30% by weight based on the total triblock copolymer weight.

The polymer comprising an ion conductive group according to the present invention is to provide an ion conductive block of a triblock copolymer according to the present invention, preferably a triblock copolymer consisting of a hydrophobic block, a hydrophilic block and an ion conductive block, For this purpose, any polymer polymer containing a conventional ion conductive group in the art may be used, but a polymer polymer including a sulfonic acid group may be specifically used, and polystyrene sulfonic acid (styrene) is recommended. sulfonic acid, polymethyl propene sulfonic acid, polysulfopropyl methacrylate, polysulfoethyl methacrylate, polysulfobutyl methacrylate, Polysulfopropyl acrylate ate), polysulfoethyl acrylate (sulfoethyl acrylate), polysulfobutyl acrylate (sulfobutyl acrylate) or a mixture thereof is preferably used, the amount of the use is 40 to 40 based on the total triblock copolymer weight It is recommended to use 80% by weight.

,

,

,

등으로부터 중합되어 제조되는 것이 좋다.At this time, the polymer containing the ion conductive group is a monomer for forming an ion conductive block, that is, an ion conductive monomer, for example

,

,

,

It is good to superpose | polymerize and manufacture from etc.

On the other hand, the hydrophobic-hydrophilic-ion conductive triblock copolymer according to the present invention is a polymer electrolyte membrane finally prepared, preferably a hydrogen ion conductive composite triblock copolymer electrolyte membrane, more preferably a hydrogen ion conductive composite tree for fuel cells In order to improve the hydrogen ion conductivity and mechanical properties of the block copolymer electrolyte membrane, a triblock copolymer and an inorganic ion conductor solution are prepared by mixing with an inorganic ion conductor to prepare a solution of the triblock copolymer and an inorganic ion conductor, followed by solution casting and solvent drying to obtain a polymer electrolyte membrane, preferably hydrogen. An ion conductive composite triblock copolymer electrolyte membrane is prepared.

In this case, the polymer electrolyte membrane, preferably a hydrogen ion conductive composite triblock copolymer electrolyte membrane is a triblock copolymer 40 including a hydrophobic block, a hydrophilic block and an ion conductive block represented by the formula (1) based on the weight of the entire polymer electrolyte membrane To 90% by weight and 10 to 60% by weight inorganic ion conductor.

Here, the inorganic ion conductor may improve the hydrogen ion conductivity and mechanical strength of the finally prepared polymer electrolyte membrane, preferably the hydrogen ion conductive composite triblock copolymer electrolyte membrane, and increase the thermal properties and moisturizing effects at high temperatures. Any inorganic, preferably inorganic, ion ionic conductor may be used, but preferably phosphotungstic acid, silicon tungsten acid, zirconium hydrogen phosphate, or It is preferable to use a mixture thereof, and the amount of the mixture is preferably 10 to 60% by weight based on the weight of the entire polymer electrolyte membrane, preferably the hydrogen-ion conductive composite triblock copolymer electrolyte membrane.

In addition, the inorganic ion conductor may interact with the hydrophilic block and the ion conductive block, for example, secondary bonds such as hydrogen bonding, ionic bond, and dipole-dipole interaction. Have

The solution casting according to the present invention may be any conventional solution casting method in the art for preparing a polymer electrolyte membrane, preferably a hydrogen ion conductive composite triblock copolymer electrolyte membrane, and solvent drying may be used for solution casting. Although it does not specifically limit if it is a conventional method in the art which removes a solvent by drying the triblock copolymer and inorganic ion conductor solution shape | molded by the preferable thing, Preferably a preferable drying temperature is 20-150 degreeC.

The polymer electrolyte membrane according to the present invention, preferably the hydrogen ion conductive composite triblock copolymer electrolyte membrane exhibits a microphase separated structure, and exhibits better mechanical, chemical, thermal properties and ionic conductivity than conventional polymer electrolyte membranes. Indicates.

In addition, the thickness of the polymer electrolyte membrane, preferably the hydrogen-ion conductive composite triblock copolymer electrolyte membrane, according to the present invention is not particularly limited, but if the thickness is too thin, the strength of the polymer electrolyte membrane is excessively lowered and the thickness is too thick. The internal resistance of the surface fuel cell may be excessively increased. In view of this, the thickness of the polymer electrolyte membrane may be about 30 to 200 μm.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. However, the following description is only for illustrating the present invention in detail and is not limited to the scope of the present invention by the following description.

1 is a flow chart illustrating a method of manufacturing a hydrogen ion conductive composite triblock copolymer electrolyte membrane according to the present invention.

As illustrated in FIG. 1, a method of preparing a polymer electrolyte membrane, preferably a hydrogen ion conductive composite triblock copolymer electrolyte membrane, according to the present invention will be described in more detail.

First, iii) polymerizing the hydrophobic monomer to prepare a hydrophobic homopolymer composed of a polymer polymer containing 10 to 30% by weight of hydrophobic groups based on the total triblock copolymer weight;

Ii) A hydrophobic-hydrophilic diblock copolymer is prepared by mixing a polymer polymer comprising 10 to 30% by weight of hydrophilic groups based on the total weight of the triblock copolymer prepared by polymerizing the hydrophobic single polymer and the hydrophilic monomer of step iii). Manufacturing step;

Iii) hydrophobicity by mixing a hydrophobic-hydrophilic diblock copolymer of step ii) with a polymer polymer containing 40 to 80% by weight of an ion conductive group based on the total triblock copolymer weight prepared by polymerizing an ion conductive monomer. Preparing a hydrophilic-ion conductive triblock copolymer;

Iii) 40 to 90% by weight of the hydrophobic-hydrophilic-ion conductive triblock copolymer and 10 to 60% by weight of the inorganic ion conductor based on the total weight of the polymer electrolyte membrane, based on the total weight of the polymer electrolyte membrane. Mixing with a solvent to prepare a triblock copolymer and an inorganic ion conductor solution;

Iii) a solution casting step of molding the triblock copolymer and inorganic ion conductor solution of step iv) into an electrolyte membrane form;

Iii) drying the solvent at a temperature of 20 to 150 ° C. for 6 to 48 hours after step iii) is completed to remove the solvent.

,

,

,

,

,

,

등으로부터 중합된 고분자를 사용하는 것이 좋다. 이때, 상기 소수성 단량체의 R은 C_nH_2n+1(여기서, n은 정수임) 또는

이다.Here, the polymer polymer comprising the hydrophobic group of step iii) is to provide a hydrophobic block of the triblock copolymer according to the present invention, preferably a triblock copolymer composed of a hydrophobic block, a hydrophilic block and an ion conductive block. Any polymer may be used as long as it is a polymer containing hydrophobic groups, but preferably a monomer for forming a hydrophobic block, that is, a hydrophobic monomer, for example

,

,

,

,

,

,

It is preferable to use a polymer polymerized from the like. Wherein R in the hydrophobic monomer is C _n H _{2n + 1} (where n is an integer) or

to be.

In addition, representative materials that can be used as the polymer containing the hydrophobic group described above include polystyrene, polyalkylstyrene, polymethacrylate, polyacrylate, polyisoprene, polybutadiene, polyacrylamide, polyvinyl ether or mixtures thereof. It is preferable to use a copolymer including the amount thereof, and the amount of use may be 10 to 30% by weight based on the total weight of the triblock copolymer.

,

,

,

,

등으로부터 중합된 고분자를 사용하는 것이 좋다.The polymer comprising the hydrophilic group of step ii) is to provide a hydrophilic block of a triblock copolymer according to the present invention, preferably a triblock copolymer composed of a hydrophobic block, a hydrophilic block and an ion conductive block. Any polymer may be used as long as it is a polymer polymer capable of interacting with an ionic conductor, preferably a polymer polymer including a hydrophilic group, but preferably a monomer for forming a hydrophilic block, that is, a hydrophilic monomer, for example

,

,

,

,

It is preferable to use a polymer polymerized from the like.

Representative materials that can be used as the polymer containing the hydrophilic group described above include polyhydroxy methacrylate, polyhydroxy acrylate, polyhydroxy methacrylamide, polyhydroxy acrylamide, polyvinylphenol, polyvinyl It is preferable to use a copolymer comprising alcohol, polyethylene glycol, polypropylene glycol or mixtures thereof, and the amount of the copolymer is preferably 10 to 30% by weight based on the total triblock copolymer weight.

The polymer comprising the ion conductive group of step iii) according to the present invention provides a triblock copolymer according to the invention, preferably an ion conductive block of a triblock copolymer consisting of a hydrophobic block, a hydrophilic block and an ion conductive block For this purpose, any polymer polymer containing a conventional ion conductive group in the art may be used for this purpose, but it is preferable to use a polymer polymer including a sulfonic acid group. Styrene sulfonic acid, polymethyl propene sulfonic acid, polysulfopropyl methacrylate, polysulfoethyl methacrylate, polysulfobutyl methacrylate sulfobutyl methacrylate), polysulfopropyl acrylate (su It is preferable to use a copolymer including lfopropyl acrylate, polysulfoethyl acrylate, polysulfobutyl acrylate or a mixture thereof, the amount of which is 40 based on the total triblock copolymer weight. It is preferable to use from 80% by weight.

,

,

,

등으로부터 중합되어 제조되는 것이 좋다.At this time, the polymer containing the ion conductive group is a monomer for forming an ion conductive block, that is, an ion conductive monomer, for example

,

,

,

It is good to superpose | polymerize and manufacture from etc.

Step iii) Inorganic ion conductor according to the present invention improves the hydrogen ion conductivity and mechanical strength of the finally prepared polymer electrolyte membrane, preferably the hydrogen ion conductive composite triblock copolymer electrolyte membrane, thermal properties and moisturizing effect at high temperature Any inorganic material, preferably an inorganic ion conductor, may be used as long as it is an inorganic ion conductor capable of increasing the amount thereof. However, phosphotungstic acid, silitcotungstic acid, and zirconium hydrogen phosphate may be used. It is preferable to use hydrogen phosphate) or a mixture thereof, and the amount thereof may be used in an amount of 10 to 60% by weight based on the weight of the entire polymer electrolyte membrane, preferably, the hydrogen ion conductive composite triblock copolymer electrolyte membrane.

On the other hand, the solvent in which the triblock copolymer and the inorganic ion conductor in step iii) are dissolved may be used as long as it is a conventional solvent in the art that can dissolve the triblock copolymer and the inorganic ion conductor. Preferably, it is preferable to use normal methyl pyrrolidone, dimethyl formamide, dimethyl sulfoxide or a mixture thereof, and the amount thereof is 1 to 20% by weight based on the total weight of the polymer electrolyte membrane including the triblock copolymer and the inorganic ion conductor. It is good to use

The solution casting step of step iii) according to the present invention may be any conventional solution casting method in the art for preparing a polymer electrolyte membrane, preferably a hydrogen ion conductive composite triblock copolymer electrolyte membrane.

In addition, the solvent drying step of step iii) according to the present invention is not particularly limited as long as it is a conventional method in the art to remove the solvent by drying the triblock copolymer and the inorganic ion conductor solution formed by solution casting. It is preferable to dry the polymer electrolyte membrane, preferably the hydrogen ion conductive composite triblock copolymer electrolyte membrane by evaporating the solvent for 6 to 48 hours in the temperature range of 150 to 150 ° C.

The polymer electrolyte membrane, preferably a hydrogen ion conductive composite triblock copolymer electrolyte membrane, according to the present invention prepared according to the above-described manufacturing method is a fuel cell, electrolysis, electrodialysis, diffusion dialysis, pressure dialysis, chloro-alkali separation membrane and / Alternatively, the present invention may be used in an electric / chemical device requiring an electrolyte membrane such as a battery. In the present invention, an application mode of the hydrogen ion conductive composite triblock copolymer electrolyte membrane is specifically limited to a case where the electrolyte membrane is applied to a fuel cell. Is as follows.

A typical fuel cell is configured to include a cathode, an anode, and an electrolyte membrane positioned between the cathode and the anode. The fuel cell according to the present invention includes an electrolyte including a triblock copolymer represented by Chemical Formula 1 and an inorganic ion conductor. The membrane is used as the electrolyte membrane between the cathode and the anode.

In a particular embodiment, the hydrogen-ion conductive composite triblock copolymer electrolyte membrane according to the present invention is a polymer electrolyte membrane fuel cell (PEMFC) for supplying a gas containing hydrogen to the anode and a mixture of methanol and water or an aqueous methanol solution to the anode It can be used in direct methanol fuel cell (DMFC).

The cathode may include a catalyst layer for promoting a reduction reaction of oxygen, and the catalyst layer may include a polymer having a catalyst particle and a cation exchange group. In this case, a platinum catalyst, a platinum supported carbon catalyst (Pt / C catalyst) and the like may be used as the catalyst.

The anode includes a catalyst layer for promoting oxidation of a fuel such as hydrogen, methanol, ethanol, and the like, and the catalyst layer may include a catalyst particle and a polymer having a cation exchange group. In this case, platinum catalyst, platinum-ruthenium catalyst, platinum-supported carbon catalyst, platinum-ruthenium-supported carbon catalyst, etc. may be used as the catalyst, and platinum-ruthenium catalyst or platinum-ruthenium-supported carbon catalyst may be an anode of organic fuel other than hydrogen. This is useful when feeding directly to

The catalyst used for the negative electrode and the positive electrode may be a catalyst metal particle itself or a supported catalyst including the catalyst metal particle and the catalyst carrier. As the catalyst carrier, solid particles having conductivity such as carbon powder and having micropores capable of supporting catalytic metal particles may be used.

As the carbon powder, carbon black, acetylene black, activated carbon powder, carbon nanofiber powder, or a mixture thereof may be used.

The catalyst layer of the cathode and the anode is in contact with the polymer electrolyte membrane.

The cathode and the anode may further include a gas diffusion layer in addition to the catalyst layer, and the gas diffusion layer includes a porous material having electrical conductivity, and serves as a current collector and an access passage of reactants and products.

As the gas diffusion layer, a carbon paper, preferably a water repellent treated carbon paper, and more preferably a water repellent treated carbon paper coated with a water repellent treated carbon black layer may be used.

Here, the water-repellent treated carbon paper includes a hydrophobic polymer such as PTFE (polytetrafluoroethylene), and the hydrophobic polymer is sintered.

At this time, the water repellent treatment of the gas diffusion layer is to secure the access passage for the polar liquid reactant and the gas reactant at the same time.

In the water-repellent treated carbon paper having the water-repellent treated carbon black layer, the water-repellent treated carbon black layer contains a hydrophobic polymer such as PTFE as carbon black and a hydrophobic binder, and adheres to one side of the water-repellent treated carbon paper. The hydrophobic polymer of the water repellent treated carbon black layer is sintered.

Since the negative electrode and the positive electrode may be manufactured and configured by methods known in various conventional literatures as conventional negative electrodes and positive electrodes in the art, the present invention will not be described in detail.

Fuels that can be supplied to the anode of the fuel cell according to the present invention include hydrogen, methanol, ethanol and the like, preferably liquid fuels containing polar organic fuel and water, and more preferably methanol aqueous solution. In this case, methanol, ethanol, or the like may be used as the polar organic fuel.

In the fuel cell according to the present invention, since the crossover phenomenon of the polar organic fuel is suppressed by the hydrogen ion conductive composite triblock copolymer electrolyte membrane, a higher concentration of methanol aqueous solution can be used.

In addition, even when a low concentration of methanol aqueous solution is used, the crossover phenomenon of the polar organic fuel is further suppressed by the polymer electrolyte membrane, and the polymer electrolyte membrane has excellent hydrogen ion conductivity, so that the fuel cell of the present invention is substantially Has improved life and efficiency.

Hereinafter, the present invention will be described in detail through examples. However, the following examples are only for illustrating the present invention in detail and are not intended to limit the scope of the present invention by these examples.

Ionic conductivity of the polymer electrolyte membrane prepared according to the embodiment of the present invention was measured by the following test method.

<Test method>

Experiment for measuring ion conductivity of polymer electrolyte membrane

The prepared polymer electrolyte membrane, specifically the hydrogen ion conductive composite triblock copolymer electrolyte membrane, was washed 10 times with distilled water and dried, and the ion conductivity of the prepared polymer electrolyte membrane was measured using a 4-pole electrode device.

Here, the ion conductivity is a hydrogen ion conductive composite triblock copolymer electrolyte membrane prepared between the four electrodes to maximize the contact with the electrode, and then the terminals of the electrode connected to the AC impedance measurement analyzer [IM6e, Germany] and a computer Measured. At this time, the frequency range was 1 Hz to 1 MHz, and the potential was 10 Hz.

<Example 1>

Preparation of Hydrophobic-hydrophilic-ion Conductive Triblock Copolymers

Iii) polystyrene homopolymer manufacturing step

First, 0.29 g of copper chloride (CuCl, Aldrich, USA) and hexamethyltriethylenetetramine (Aldrich, USA) in 20 g of styrene (Mw: 104.15 g / mol, Aldrich, USA) at 1 atmosphere of room temperature (25 ° C.) 1.24 ml was added.

Then, nitrogen was injected for 30 minutes while stirring the solution, and then 0.22 ml of methyl bromopropionate (99% methyl 2-bromo-propionate, Aldrich, USA) was added.

Then, the solution was injected with nitrogen for 30 minutes while stirring, and then placed in an oil bath preheated to 110 ° C. and reacted for 5 hours.

Subsequently, 70 ml of tetrahydrofuran (THF, Aldrich, USA) was added to the finished polymer and diluted. The solution was precipitated in methanol (Aldrich, USA) solvent and filtered to recover the polymer.

The polymer was then redissolved in toluene (Aldrich, USA) and purified by reprecipitation three times in methanol solvent to prepare a polystyrene homopolymer as a polymer containing hydrophobic groups.

The polymer was then dried in vacuo at room temperature (25 ° C.) for 24 hours.

Ii) polystyrene-polyhydroxymethacrylate diblock copolymer preparation step

First, 5 g of polystyrene homopolymer, which is a polymer polymer containing a hydrophobic group of step iv) described above at 1 atmosphere of room temperature (25 ° C.), was dissolved in 10 ml of toluene (Aldrich, USA) and stirred at about 25 ° C. for about 1 hour. .

Then, 5 g (4.67 ml) of hydroxyl methacrylate (hydroxyl methacrylate, HEMA, Aldrich, USA) was added to the prepared solution, followed by stirring to prepare a uniform solution.

Next, 0.015 g of copper chloride (CuCl, Aldrich, USA) and 0.0625 ml of hexamethyltriethylenetetramine (Aldrich, USA) were added to the mixed solution.

Then, the solution was injected with nitrogen for 30 minutes while stirring, and then placed in a 50 degreeC preheated oil bath, and reacted for 2 hours and 30 minutes.

Then, the polymer solution after the reaction was precipitated in methanol (Methanol, Aldrich, USA) -nucleic acid (Aldrich, USA) solvent in a volume ratio of 1: 1 and filtered to prepare a polymer.

Then, the polymer was re-dissolved in normal methylpyrrolidone (NMP, Aldrich, USA), and purified by re-precipitation three times in methanol-nucleic acid solvent.

The polymer was then dried in vacuo at room temperature for 24 hours to produce a polystyrene-polyhydroxymethacrylate diblock copolymer as a hydrophobic-hydrophilic diblock copolymer.

Iii) polystyrene-polyhydroxy methacrylate-polystyrenesulphonic acid triblock copolymer

First, the above-mentioned step at room temperature (25 ° C.) 1 atmosphere ii) 5 g of a hydrophobic-hydrophilic diblock copolymer polystyrene-polyhydroxymethacrylate diblock copolymer was added to 50 ml of normal methylpyrrolidone (NMP, Aldrich, USA) After dissolution, the mixture was stirred at about 25 ° C. for about 1 hour.

Next, 5 g of styrene sulfonic acid sodium salt (SSA, Aldrich, USA) was dissolved in a separate 25 ml of dimethyl sulfoxide (DMSO, Aldrich, USA).

Then, when the solution in which the polystyrene-polyhydroxymethacrylate diblock copolymer in which the hydrophobic-hydrophilic diblock copolymer is dissolved and the solution in which the styrene sulfonic acid sodium salt is dissolved are sufficiently dissolved, they are mixed and stirred to form a uniform solution. Prepared.

Next, 0.015 g of copper chloride (CuCl, Aldrich, USA) and 0.0625 ml of hexamethyltriethylenetetramine (Aldrich, USA) were added to the mixed solution.

Then, the solution was infused with nitrogen for 30 minutes with stirring and placed in an oil bath preheated to 110 ° C. and reacted for 24 hours.

Then, the polymer solution after the reaction was precipitated in a methanol-nucleic acid (1: 1 volume ratio) solvent and filtered to prepare a polymer.

The polymer was then redissolved in dimethylsulfoxide and purified by re-precipitation three times in methanol-nucleic acid solvent to recover the polymer.

The polymer was then dried in vacuo at room temperature for 24 hours to prepare a polystyrene-polyhydroxymethacrylate-polystyrenesulphonic acid triblock copolymer, which is a hydrophobic-hydrophilic-ion conductive triblock copolymer.

<Example 2>

Manufacture of composite triblock electrolyte membrane

Triblock copolymers prepared according to Example 1, specifically 0.9 g of polystyrene-polyhydroxymethacrylate-polystyrenesulphonic acid triblock copolymer and phosphotungstic acid, PWA, H ₃ [P (W ₃ O ₁₀ ) ₄ ], Aldrich, USA) 0.1g was dissolved in 20ml of dimethyl sulfoxide to prepare a mixed solution.

Then, the mixed solution was poured into a glass dish (Petri dish, Korean Science, Korea).

Then, the glass plate was placed in a drying oven at 80 ° C. and dried for two days to remove the solvent, and then the remaining solvent was completely removed from the vacuum oven.

Next, the polymer membrane was precipitated in 1 N aqueous sulfuric acid solution for one day to replace sodium cations with hydrogen ions.

Then, the polymer membrane was washed 10 times with distilled water to make the solution neutral, and then ion conductivity was measured at about 25 ° C.

The results are shown in Table 1.

<Example 3>

In the same manner as in Example 2, 0.8g instead of 0.9g of polystyrene-polyhydroxymethacrylate-polystyrenesulphonic acid triblock copolymer according to Example 1 and 0.2g instead of 0.1g of intungstic acid were used.

The results are shown in Table 1.

<Example 4>

In the same manner as in Example 2, 0.7g instead of 0.9g of polystyrene-polyhydroxy methacrylate-polystyrenesulphonic acid triblock copolymer according to Example 1 and 0.3g instead of 0.1g of tungsten acid were used.

The results are shown in Table 1.

<Example 5>

The same procedure as in Example 2 was carried out, except that 0.6 g of polystyrene-polyhydroxy methacrylate-polystyrene sulfonic acid triblock copolymer according to Example 1 and 0.4 g of 0.1 g of tungsten acid were used.

The results are shown in Table 1.

Characteristics of Composite Triblock Copolymer Electrolyte Membrane Copolymer: PWA weight% ratio Thickness (μm) Ionic Conductivity (S / cm) Swelling in water Pure Tree Block no PWA 150 4.87 x 10 ^-2 130% Example 2 9: 1 140 6.38 x 10 ^-2 71.5% Example 3 8: 2 84 6.50 x 10 ^-2 65.4% Example 4 7: 3 110 6.42 x 10 ^-2 52.6% Example 5 6: 4 94 6.26 x 10 ^-2 48.6%

As shown in Table 1, in the polymer electrolyte membrane according to the present invention, as the content of phosphorus tungstic acid (PWA) was increased, the hydrogen ion conductivity increased slightly and the swelling of water continued to decrease.

As described above, those skilled in the art will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, it should be understood that the embodiments described above are all illustrative and not restrictive. The scope of the present invention should be construed as being included in the scope of the present invention all changes or modifications derived from the meaning and scope of the claims to be described later rather than the detailed description and equivalent concepts thereof.

The polymer electrolyte membrane according to the present invention, specifically the hydrogen ion conductive composite triblock copolymer electrolyte membrane, has thermal, mechanical and chemical stability, and exhibits high ion conductivity, low fuel permeability, low dehydration effect, and low gas permeability. Therefore, the manufacturing cost and manufacturing time can be reduced by a simple synthesis process.

Claims (12)

Hydrogen-ion conductive composite comprising 40 to 90% by weight of a triblock copolymer comprising a hydrophobic block, a hydrophilic block and an ion conductive block and 10 to 60% by weight of an inorganic ion conductor based on the total weight of the polymer electrolyte membrane Triblock Copolymer Electrolyte Membrane:

------ (Formula 1) Wherein R ₁ is H or CH ₃ ; R ₂ is

,

, C _n H _{2n + 1} , OC _n H _{2n + 1} , COO-C _n H _{2n + 1} ; R ₃ is OH,

, COO (CH ₂ ) _n -OH, CONH (CH ₂ ) _n -OH; R ₄ is

_{, (CH 2) n -SO 3} -, COO (CH 2) n -SO 3 - , and (wherein n is any integer); x, y and z are each 100 to 10,000; b is a block. The method of claim 1, The triblock copolymer including the hydrophobic block, the hydrophilic block and the ion conductive block may include 10 to 30% by weight of a hydrophobic block based on the total triblock copolymer weight; 10-30% by weight of hydrophilic blocks; And 40 to 80% by weight of an ion conductive block. The method of claim 1, Hydrogen-ion conductive composite triblock copolymer electrolyte, characterized in that the hydrophobic block is polystyrene, polyalkylstyrene, polymethacrylate, polyacrylate, polyisoprene, polybutadiene, polyacrylamide, polyvinyl ether or mixtures thereof membrane. The method of claim 1, The hydrophilic block is polyhydroxy methacrylate, polyhydroxy acrylate, polyhydroxy methacrylamide, polyhydroxy acrylamide, polyvinylphenol, polyvinyl alcohol, polyethylene glycol, polypropylene glycol or mixtures thereof Hydrogen ion conductive composite triblock copolymer electrolyte membrane, characterized in that. The method of claim 1, The ion conductive block is polystyrene sulfonic acid, polymethyl propene sulfonic acid, polysulfopropyl methacrylate, polysulfoethyl methacrylate, polysulfobutyl methacrylate, polysulfopropyl acrylate, polysulfoethyl acrylate, poly A hydrogen ion conductive composite triblock copolymer electrolyte membrane, characterized in that sulfobutyl acrylate or a mixture thereof. The method of claim 1, Hydrogen ion conductive composite triblock copolymer electrolyte membrane, characterized in that the inorganic ion conductor is phosphorus tungstic acid, silicon tungstic acid, zirconium hydrogen phosphate or a mixture thereof. A fuel cell comprising the hydrogen ion conductive composite triblock copolymer electrolyte membrane according to any one of claims 1 to 6. Iii) polymerizing the hydrophobic monomer to prepare a hydrophobic homopolymer composed of a polymer polymer containing 10 to 30 wt% of hydrophobic groups based on the total triblock copolymer weight; Ii) A hydrophobic-hydrophilic diblock copolymer is prepared by mixing a polymer polymer comprising 10 to 30% by weight of hydrophilic groups based on the total weight of the triblock copolymer prepared by polymerizing the hydrophobic single polymer and the hydrophilic monomer of step iii). Manufacturing step; Iii) hydrophobicity by mixing a hydrophobic-hydrophilic diblock copolymer of step ii) with a polymer polymer containing 40 to 80% by weight of an ion conductive group based on the total triblock copolymer weight prepared by polymerizing an ion conductive monomer. Preparing a hydrophilic-ion conductive triblock copolymer; Iii) 40 to 90% by weight of the hydrophobic-hydrophilic-ion conductive triblock copolymer and 10 to 60% by weight of the inorganic ion conductor based on the total weight of the polymer electrolyte membrane, based on the total weight of the polymer electrolyte membrane. Mixing with a solvent to prepare a triblock copolymer and an inorganic ion conductor solution; Iii) a solution casting step of molding the triblock copolymer and inorganic ion conductor solution of step iv) into an electrolyte membrane form; And Iii) a method for producing a hydrogen ion conductive composite triblock copolymer electrolyte membrane comprising a solvent drying step of removing the solvent by drying at a temperature of 20 to 150 ° C. for 6 to 48 hours after the step iii) is completed. The method of claim 8, Hydrogen-ion conductive composite triblock copolymer electrolyte, characterized in that the hydrophobic block is polystyrene, polyalkylstyrene, polymethacrylate, polyacrylate, polyisoprene, polybutadiene, polyacrylamide, polyvinyl ether or mixtures thereof Method of Making Membranes. The method of claim 8, The hydrophilic block is polyhydroxy methacrylate, polyhydroxy acrylate, polyhydroxy methacrylamide, polyhydroxy acrylamide, polyvinylphenol, polyvinyl alcohol, polyethylene glycol, polypropylene glycol or mixtures thereof Method for producing a hydrogen ion conductive composite triblock copolymer electrolyte membrane, characterized in that. The method of claim 8, The ion conductive block is polystyrene sulfonic acid, polymethyl propene sulfonic acid, polysulfopropyl methacrylate, polysulfoethyl methacrylate, polysulfobutyl methacrylate, polysulfopropyl acrylate, polysulfoethyl acrylate, poly Method for producing a hydrogen ion conductive composite triblock copolymer electrolyte membrane, characterized in that the sulfobutyl acrylate or a mixture thereof. The method of claim 8, The inorganic ion conductor is phosphorus tungstic acid, silicon tungstic acid, zirconium hydrogen phosphate or a mixture thereof, the method of producing a hydrogen ion conductive composite triblock copolymer electrolyte membrane.

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