WO2017171285A2 - Ion-exchange membrane, method for manufacturing same, and energy storing device comprising same - Google Patents

Abstract

The present invention relates to an ion-exchange membrane, a method for manufacturing the same, and an energy storing device comprising the same. The ion-exchange membrane comprises: a porous support body comprising multiple pores; an ionic conductor filling the pores of the porous support body; and a silica coating layer that is positioned on the surface of the porous support body and comprises silica and an ionic conductor. An ion-exchange membrane according to an embodiment of the present invention has an improved bondability at an interface with other materials, which are bonded to the ion-exchange membrane, by means of surface energy control. Therefore, the ion-exchange membrane has a long-term durability maintained stably and thus can improve bonding durability not only when applied to an energy storing device, but also when applied to a power generating system. In addition, an ion-exchange membrane according to an embodiment of the present invention has a reduced resistance at an interface with other materials by means of surface energy control, and the through-plane exchange performance of the ion-exchange membrane is accordingly improved, making it possible to improve not only the bonding durability, but also the system efficiency.

Description

Ion-exchange membrane, method for manufacturing same, and energy storage device including same

The present invention relates to an ion exchange membrane, a method for manufacturing the same, and an energy storage device including the same. More specifically, the ion exchange membrane has improved interfacial bonding with other materials bonded to the ion exchange membrane through surface energy control, and the interface resistance is reduced. An exchange membrane, a method for manufacturing the same, and an energy storage device including the same.

In order to solve the problem of depletion of fossil fuels and environmental pollution, efforts are being made to save fossil fuels or to apply renewable energy to more fields by improving the use efficiency.

Renewable energy sources such as solar and wind are used more efficiently than before, but these energy sources are intermittent and unpredictable. These characteristics limit the dependence on these energy sources, and the ratio of renewable energy sources among primary power sources is very low.

Rechargeable batteries provide a simple and efficient method of storing electricity, and thus, efforts have been made to utilize them as power sources for intermittent auxiliary power, small appliances such as laptops, tablet PCs, and mobile phones by miniaturizing them to increase mobility.

Among them, a redox flow battery (RFB) is a secondary battery capable of storing energy for a long time by repeating charging and discharging by an electrochemical reversible reaction of an electrolyte. The stack and electrolyte tank are independent of each other, which determines the capacity and output characteristics of the battery, freeing cell design and reducing installation space.

In addition, the redox flow battery has a load leveling function that can be installed in a power plant, a power system, or a building to cope with a sudden increase in power demand, and a function for compensating or suppressing a power failure or an instantaneous low voltage. It is a powerful energy storage technology and is suitable for large scale energy storage.

Redox flow cells generally consist of two separate electrolytes. One stores the electroactive material in the negative electrode reaction and the other is used for the positive electrode reaction. In the real redox flow battery, the electrolyte reaction is different from each other at the positive electrode and the negative electrode, and there is a pressure difference between the positive electrode side and the negative electrode side because the electrolyte flow occurs. Reactions of the positive and negative electrolytes in the all-vanadium redox flow battery, which is a typical redox flow battery, are shown in Schemes 1 and 2, respectively.

Scheme 1

Scheme 2

Therefore, in order to overcome the pressure difference at both electrodes and to show excellent battery performance even after repeated charging and discharging, an ion exchange membrane having improved physical and chemical durability is required. It is the core material that accounts for the price of about%.

As such, in the redox flow battery, the ion exchange membrane is a key component that determines battery life and price. In order to commercialize the redox flow battery, the ion permeability of the ion exchange membrane must be high and the crossover of the vanadium ions must be low. The resistance must be high, the ionic conductivity must be high, mechanically and chemically stable, high durability, and low cost.

Meanwhile, polymer electrolyte membranes commercialized as ion exchange membranes have been used for decades and are continuously being studied. Recently, direct methanol fuel cells (DMFC) or polymer electrolyte membrane fuel cells (PEMFC; polymer) have been used. Numerous researches on ion exchange membranes are actively conducted as mediators for transferring ions used in electrolyte membrane fuel cells, proton exchange membrane fuel cells, redox flow batteries, and water purification equipment.

A widely used material for ion exchange membranes is Nafion ™ based membrane, a polymer containing perfluorinated sulfonic acid group, DuPont, USA. The membrane has an ion conductivity of 0.08 S / cm at room temperature, excellent mechanical strength and chemical resistance at a saturated water content, and has a stable performance as an electrolyte membrane for use in automotive fuel cells. In addition, commercially available membranes of a similar type include Asahi Chemicals' Aciplex-S membrane, Dow Chemical's Dow membrane, Asahi Glass's Flemion membrane, Gore & Associate's GoreSelcet membrane, etc., and polymers perfluorinated in alpha or beta form by Ballard Power System of Canada It is under development research.

However, the membranes are expensive and difficult to synthesize, which makes them difficult to mass-produce, as well as crossover in electrical energy systems such as redox flow cells, ions such as low ion conductivity at high or low temperatures. As an exchange membrane, there is a disadvantage in that the efficiency is greatly reduced.

It is an object of the present invention to provide an ion exchange membrane with improved interfacial bonding with other materials and reduced interfacial resistance through surface energy control.

Another object of the present invention is to provide a method for producing the ion exchange membrane.

Still another object of the present invention is to provide an energy storage device including the ion exchange membrane.

According to one embodiment of the present invention, a porous support comprising a plurality of pores (pore), an ion conductor filling the pores of the porous support, and a silica coating layer located on the surface of the porous support comprising a silica and an ion conductor It provides an ion exchange membrane comprising a.

The pores of the porous support may further include silica mixed with the ion conductor.

With respect to 100 parts by weight of silica included in the silica coating layer, silica contained in the pores of the porous support may be 10 parts by weight or less.

The surface of the silica coating layer may include a pattern in which a plurality of grooves are formed regularly or irregularly.

The surface of the silica coating layer may have a fine roughness to have a surface roughness.

The surface of the silica coating layer may include a surface treated with fluorine gas.

According to another embodiment of the present invention, a porous support including a plurality of pores (pore) and an ion conductor for forming an ion conductor coating layer on the surface of the porous support while filling the pores of the porous support, the ion The surface of the conductor coating layer provides an ion exchange membrane in which a plurality of grooves comprises a pattern formed regularly or irregularly.

According to another embodiment of the present invention, a porous support including a plurality of pores (pore) and an ion conductor for forming an ion conductor coating layer on the surface of the porous support while filling the pores of the porous support, The surface of the ion conductor coating layer provides an ion exchange membrane in which fine irregularities are formed to have a surface roughness.

The size of the fine concave-convex may be 0.1 to 20% by length based on the total thickness of the ion conductor coating layer.

According to another embodiment of the present invention, a porous support including a plurality of pores (pore) and an ion conductor for forming an ion conductor coating layer on the surface of the porous support while filling the pores of the porous support, The ion conductor coating layer provides an ion exchange membrane comprising a surface treated with fluorine gas.

The ion conductor is a hydrocarbon-based polymer whose main chain includes a benzene ring and an ion exchange group is attached to the benzene ring, and the surface treated with fluorine gas in the ion conductor coating layer is treated with the benzene by the fluorine gas treatment. Fluorine may be substituted in the ring.

A fluorine-based ion conductor coating layer may be further included on the surface treated with the fluorine gas of the ion conductor coating layer.

The porous support may be a hydrocarbon-based porous support, and the ion conductor may be a hydrocarbon-based ion conductor.

According to another embodiment of the present invention, the step of preparing a silica-ion conductor mixture by mixing the silica dispersion and the ion conductor, and the silica-ion conductor mixture on the surface of the porous support comprising a plurality of pores (pore) It provides a method for producing an ion exchange membrane comprising the step of coating to form a silica coating layer.

In the forming of the silica coating layer, the silica-ion conductor mixture may form the silica coating layer on the surface of the porous support while filling the pores of the porous support.

Forming the silica coating layer may include filling the pores of the porous support with an ion conductor, and coating the silica-ion conductor mixture on the surface of the porous support to form the silica coating layer.

The method of manufacturing the ion exchange membrane may further include etching the surface of the silica coating layer after the forming of the silica coating layer.

The method of manufacturing the ion exchange membrane may further include treating the surface of the silica coating layer with fluorine gas after the forming of the silica coating layer.

According to another embodiment of the present invention, filling the pores of the porous support comprising a plurality of pores (pore) with an ion conductor to form an ion conductor coating layer on the surface of the porous support, and the ion conductor coating layer It provides a method for producing an ion exchange membrane comprising the step of etching the surface.

The etching treatment may be performed by contacting the surface of the ion conductor coating layer with an etching solution selected from the group consisting of an etching solution including an organic solvent, an etching solution in which an ion conductor is diluted in an organic solvent, and a silica dispersion.

The etching treatment may be performed by any one physical treatment selected from the group consisting of laser irradiation, polishing, corona treatment, and plasma treatment.

According to another embodiment of the present invention, filling the pores of the porous support comprising a plurality of pores (pore) with an ion conductor to form an ion conductor coating layer on the surface of the porous support, and the ion conductor coating layer It provides a method for producing an ion exchange membrane comprising the step of treating the surface with fluorine gas.

The method of manufacturing the ion exchange membrane may further include forming a fluorine-based ion conductor coating layer on the fluorine gas treated ion conductor coating layer.

According to another embodiment of the present invention, an energy storage device including the ion exchange membrane is provided.

The energy storage device may be a fuel cell.

The energy storage device may be a redox flow battery.

The ion exchange membrane of the present invention improves interfacial bonding with other materials to be bonded to the ion exchange membrane through surface energy control, so that long-term durability is stably maintained. In addition, the interfacial resistance with other materials can be reduced by controlling the surface energy of the ion exchange membrane, thereby improving the through-plane exchange performance of the ion exchange membrane, thereby improving not only the bonding durability but also the efficiency of the system. You can.

1 is a schematic diagram schematically showing a full vanadium-based redox battery according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

According to an embodiment of the present invention, an ion exchange membrane includes a porous support including a plurality of pores, an ion conductor filling the pores of the porous support, and a silica and an ion conductor positioned on the surface of the porous support. Silica coating layer.

The porous support may include, as one example, a perfluorinated polymer having excellent resistance to thermal and chemical degradation. For example, the porous support may be polytetrafluoroethylene (PTFE) or tetrafluoroethylene and CF ₂ = CFC _n F _{2n +1} (n is an integer of 1 to 5) or a compound represented by Formula 1 below. It may be a copolymer.

[Formula 1]

In Formula 1, m is an integer of 0 to 15, n is an integer of 1 to 15.

The PTFE is commercially available and can be suitably used as the porous support. In addition, expanded polytetrafluoroethylene polymer (e-PTFE) having a microstructure of polymer fibrils or microstructures in which nodes are connected to each other by fibrils may be suitably used as the porous support, and the nodes do not exist. A film having a fine structure of polymer fibril, which is not used, can be suitably used as the porous support.

The porous support comprising the perfluorinated polymer can be made into a more porous and stronger porous support by extruding the dispersion polymerized PTFE onto the tape in the presence of a lubricant and stretching the material obtained thereby. In addition, the amorphous content of PTFE may be increased by heat-treating the e-PTFE at a temperature exceeding the melting point (about 342 ° C.) of the PTFE. The e-PTFE film prepared by the above method may have micropores and porosities having various diameters. The e-PTFE film prepared by the method may have at least 35% of the pores, the diameter of the micropores may be about 0.01 to 1 ㎛. In addition, the thickness of the porous support including the perfluorinated polymer can be variously changed, for example, may be 2 ㎛ to 40 ㎛, preferably 5 ㎛ to 20 ㎛. If the thickness of the porous support is less than 2 μm, the mechanical strength may be significantly reduced, whereas if the thickness is more than 40 μm, the resistance loss may increase, and the weight and integration may be reduced.

As another example of the porous support, the porous support may include a nanoweb in which nanofibers are integrated in a nonwoven form including a plurality of pores.

The nanofibers have excellent chemical resistance, and can be preferably used hydrocarbon-based polymers which have hydrophobicity and are free of morphological changes due to moisture in a high humidity environment. Specifically, the hydrocarbon-based polymer may be nylon, polyimide, polyaramid, polyetherimide, polyacrylonitrile, polyaniline, polyethylene oxide, polyethylene naphthalate, polybutylene terephthalate, styrene butadiene rubber, polystyrene, polyvinyl chloride, Polyvinyl alcohol, polyvinylidene fluoride, polyvinyl butylene, polyurethane, polybenzoxazole, polybenzimidazole, polyamideimide, polyethylene terephthalate, polyethylene, polypropylene, copolymers thereof, and mixtures thereof The polyimide excellent in heat resistance, chemical resistance, and morphological stability can be used preferably among these, It can select from the group which consists of these.

The nanoweb is an aggregate of nanofibers in which nanofibers produced by electrospinning are randomly arranged. In this case, considering the porosity and thickness of the nanoweb, 50 to 50 fiber diameters were measured using an electron scanning microscope (Scanning Electron Microscope, JSM6700F, JEOL) and calculated from the average of 40 to 5000 nm. It is preferred to have an average diameter. If the average diameter of the nanofibers is less than 40 nm, the mechanical strength of the porous support may be lowered. If the average diameter of the nanofibers exceeds 5,000 nm, the porosity may be significantly decreased and the thickness may be thickened.

The nanoweb is made of the nanofibers as described above, it may have a porosity of 50% or more. On the other hand, the nanoweb preferably has a porosity of 90% or less. If the porosity of the nanoweb exceeds 90%, morphological stability may be lowered, and thus the subsequent process may not proceed smoothly. The porosity may be calculated by the ratio of the air volume to the total nanoweb volume according to Equation 1 below. At this time, the total volume is calculated by measuring the width, length, thickness by preparing a sample of a rectangular shape, the air volume can be obtained by subtracting the total volume of the polymer inverted from the density after measuring the mass of the sample.

[Equation 1]

Porosity (%) = (air volume in nanoweb / total volume of nanoweb) X 100

In addition, the nanoweb may have an average thickness of 5 to 50 ㎛. If the thickness of the nanoweb is less than 5 ㎛ mechanical strength can be significantly reduced, while if the thickness is more than 50 ㎛ the resistance loss is increased, the weight and integration can be reduced. More preferred nanoweb thicknesses range from 10 to 30 μm.

Meanwhile, the ion conductor may be a cation conductor having a cation exchange group such as proton or an anion conductor having an anion exchange group such as hydroxy ion, carbonate or bicarbonate.

The cation exchange group may be any one selected from the group consisting of a sulfonic acid group, a carboxyl group, a boronic acid group, a phosphoric acid group, an imide group, a sulfonimide group, a sulfonamide group, and a combination thereof, and in general, may be a sulfonic acid group or a carboxyl group. have.

The cation conductor includes the cation exchange group, the fluorine-based polymer containing fluorine in the main chain; Benzimidazole, polyamide, polyamideimide, polyimide, polyacetal, polyethylene, polypropylene, acrylic resin, polyester, polysulfone, polyether, polyetherimide, polyester, polyethersulfone, polyetherimide, poly Hydrocarbon-based polymers such as carbonate, polystyrene, polyphenylene sulfide, polyether ether ketone, polyether ketone, polyaryl ether sulfone, polyphosphazene or polyphenylquinoxaline; Partially fluorinated polymers such as polystyrene-graft-ethylenetetrafluoroethylene copolymer or polystyrene-graft-polytetrafluoroethylene copolymer; Sulfone imides and the like.

More specifically, when the cationic conductor is a hydrogen ion cationic conductor, the polymers may include a cation exchange group selected from the group consisting of sulfonic acid groups, carboxylic acid groups, phosphoric acid groups, phosphonic acid groups, and derivatives thereof in the side chain thereof. Specific examples thereof include poly (perfluorosulfonic acid), poly (perfluorocarboxylic acid), copolymers of tetrafluoroethylene and fluorovinyl ether containing sulfonic acid groups, defluorinated sulfide polyether ketones or mixtures thereof. Fluorine-based polymer comprising; Sulfonated polyimide (S-PI), sulfonated polyarylethersulfone (S-PAES), sulfonated polyetheretherketone (SPEEK), sulfonated polybenzimine Sulfonated polybenzimidazole (SPBI), sulfonated polysulfone (S-PSU), sulfonated polystyrene (S-PS), sulfonated polyphosphazene and mixtures thereof Hydrocarbon-based polymers include, but are not limited thereto.

On the other hand, among the cationic conductors, hydrocarbon-based polymers excellent in ion conductivity and advantageous in terms of price can be preferably used. In addition, when a hydrocarbon-based polymer is used as the ion conductor and a hydrocarbon-based polymer is used as the porous support, the hydrocarbon-based polymer included in the hydrocarbon-based ion conductor and the hydrocarbon-based polymer included in the porous support are the same material type. In particular, when using SPI (sulfonated polyimide) as the hydrocarbon-based ion conductor and polyimide as the porous support, adhesion between the hydrocarbon-based ion conductor and the porous support can be further improved. And the interface resistance can be further lowered.

The anion conductors are polymers capable of transporting anions such as hydroxy ions, carbonates or bicarbonates, and the anion conductors are commercially available in the form of hydroxides or halides (generally chloride), the anion conductors being industrially purified (water purification), metal separation or catalytic processes.

As the anion conductor, a polymer doped with metal hydroxide may be generally used. Specifically, poly (ethersulphone) doped with metal hydroxide, polystyrene, vinyl polymer, poly (vinyl chloride), poly (vinylidene fluoride) , Poly (tetrafluoroethylene), poly (benzimidazole), poly (ethylene glycol) and the like can be used.

The ion conductor may be included in 50 to 99% by weight based on the total weight of the ion exchange membrane. If the content of the ion conductor is less than 50% by weight, the ion conductivity of the ion exchange membrane may be lowered. If the content of the ion conductor is more than 99% by weight, the mechanical strength and dimensional stability of the ion exchange membrane may be reduced. .

On the other hand, the ion exchange membrane includes a silica coating layer located on the surface of the porous support. The silica coating layer may be located only on one surface of the ion exchange membrane, or may be located on both sides of the ion exchange membrane.

The ion exchange membrane may control its surface energy through the silica coating layer. When the silica coating layer is used by bonding the ion exchange membrane with other materials, such as an electrode, it is possible to improve interfacial bonding with other materials and reduce interfacial resistance. As a result, the ion exchange membrane has improved interfacial bonding with other materials bonded to the ion exchange membrane, so that long-term durability is maintained stably, and thus the bonding durability can be improved when applied to a power generation system as well as an energy storage device. In addition, the ion exchange membrane is also reduced in interfacial resistance with the other materials, thereby improving the through-plane exchange performance of the ion exchange membrane, it is possible to improve the efficiency of the system as well as bonding durability.

The silica coating layer includes silica and an ion conductor. Since the detailed description of the ion conductor is the same as described above, repeated description is omitted.

The kind of the silica is not limited in the present invention, and all kinds of commercialized silicas can be used. In addition, although the particle size of the silica is not limited in the present invention, silica having an average particle diameter of 0.01 to 100 nm can be preferably used. When the average particle diameter of the silica is less than 0.01 nm, the dispersibility may be deteriorated, and thus the physical properties may not be uniform. When the average particle diameter is greater than 100 nm, the silica may not be uniformly distributed in the silica coating layer and the thickness of the silica coating layer may increase. Accordingly, the mechanical properties of the ion exchange membrane may be lowered.

The silica coating layer may include 1 to 50 parts by weight, preferably 5 to 30 parts by weight of the silica with respect to 100 parts by weight of the ion conductor. When the content of the silica is less than 1 part by weight based on 100 parts by weight of the ion conductor, there may be no surface energy improving effect, and when the content of the silica exceeds 50 parts by weight, performance and characteristics may be rather deteriorated due to the silica nanodispersion particles. .

The pores of the porous support may further include silica mixed with the ion conductor. However, since the present invention is intended to control the surface energy of the surface of the ion exchange membrane through the silica coating layer, it is more located on the surface of the porous support than the silica is located in the pores of the porous support. It is preferable in terms of.

Accordingly, based on 100 parts by weight of silica included in the silica coating layer, the silica contained in the pores of the porous support is preferably 10 parts by weight or less, preferably 5 parts by weight or less, and more preferably 1 to 5 parts by weight. If the content of silica contained in the pores of the porous support exceeds 10 parts by weight, the through-plane exchange performance of the ion exchange membrane may be reduced.

An ion exchange membrane according to another embodiment of the present invention includes a porous support including a plurality of pores (pore), and an ion conductor for forming an ion conductor coating layer on the surface of the porous support while filling the pores of the porous support, The surface of the ion conductor coating layer includes a pattern in which a plurality of grooves are formed regularly or irregularly.

Detailed descriptions of the porous support and the ion conductor are the same as described above, and thus repeated descriptions thereof will be omitted. Here, the ion conductor not only fills the pores of the porous support, but also forms an ion conductor coating layer made of an ion conductor on the surface of the porous support.

The ion exchange membrane may control its surface energy through the ion conductor coating layer on which the pattern is formed. When the patterned ion conductor coating layer is used by bonding the ion exchange membrane with other materials such as an electrode, the contact surface area may be increased to improve interfacial bonding with other materials and to reduce interfacial resistance. As a result, the ion exchange membrane has improved interfacial bonding with other materials bonded to the ion exchange membrane, so that long-term durability is maintained stably, and thus the bonding durability can be improved when applied to a power generation system as well as an energy storage device. In addition, the ion exchange membrane is also reduced in interfacial resistance with the other materials, thereby improving the through-plane exchange performance of the ion exchange membrane, it is possible to improve the efficiency of the system as well as bonding durability.

In this case, the ion conductor coating layer includes a pattern in which a plurality of grooves are regularly or irregularly formed on the surface thereof. The cross-sectional shape of the groove may be angled by a triangle or a square, or may be round like a semi-circle or a semi-ellipse, or the like, and the groove may be a line shape extending in the longitudinal direction, or an isolated hole without extension. hole) shape. The line shape may be a straight line or a serpentine line shape, and the hole shape may be a polygonal shape such as a circle, an ellipse or a rectangle.

An ion exchange membrane according to another embodiment of the present invention includes a porous support including a plurality of pores (pore), and an ion conductor for forming an ion conductor coating layer on the surface of the porous support while filling the pores of the porous support, The surface of the ion conductor coating layer has a fine roughness is formed to have a surface roughness. Here, the fine unevenness means that the surface of the ion conductor coating layer has a plurality of fine recesses and a plurality of fine convex portions.

Detailed descriptions of the porous support and the ion conductor are the same as described above, and thus repeated descriptions thereof will be omitted. Here, the ion conductor not only fills the pores of the porous support, but also forms an ion conductor coating layer made of an ion conductor on the surface of the porous support.

The ion exchange membrane may control its surface energy through the ion conductor coating layer in which the fine unevenness is formed. When the ion conductive coating layer having the fine unevenness is used by bonding the ion exchange membrane with other materials such as an electrode, the contact surface area may be increased to improve interfacial bonding with other materials, and also reduce interfacial resistance. As a result, the ion exchange membrane has improved interfacial bonding with other materials bonded to the ion exchange membrane, so that long-term durability is maintained stably, and thus the bonding durability can be improved when applied to a power generation system as well as an energy storage device. In addition, the ion exchange membrane is also reduced in interfacial resistance with the other materials, thereby improving the through-plane exchange performance of the ion exchange membrane, it is possible to improve the efficiency of the system as well as bonding durability.

The size of the fine unevenness of the ion conductor coating layer may be 0.1 to 20% by length, preferably 0.1 to 5% by length relative to the total thickness of the ion conductor coating layer. When the size of the fine concavo-convex exceeds 20% by length, the porous support having no conduction performance may be exposed to a surface, thereby degrading the performance of the ion exchange membrane.

Here, the size of the fine concavo-convex means the height difference between the highest convex portion of the fine convex portion and the deepest concave portion of the fine concave portion, wherein the total thickness of the ion conductor coating layer is the porous support on one surface of the porous support Means the distance from the surface to the highest convex portion. For example, the length of the fine concavo-convex is 10% by length with respect to the total thickness of the ion conductor coating layer means that the size of the fine concavo-convex is 0.1 μm when the total thickness of the ion conductor coating layer is 1 ㎛.

An ion exchange membrane according to another embodiment of the present invention includes a porous support including a plurality of pores, and an ion conductor forming an ion conductor coating layer on the surface of the porous support while filling the pores of the porous support. The ion conductor coating layer includes a surface treated with fluorine gas.

Detailed descriptions of the porous support and the ion conductor are the same as described above, and thus repeated descriptions thereof will be omitted. Here, the ion conductor not only fills the pores of the porous support, but also forms an ion conductor coating layer made of an ion conductor on the surface of the porous support.

The ion exchange membrane may control its surface energy through the surface treated with fluorine gas of the ion conductor coating layer. The surface treated with the fluorine gas of the ion conductor coating layer may improve the interfacial adhesion with other materials and reduce the interfacial resistance when the ion exchange membrane is bonded to other materials such as an electrode. As a result, the ion exchange membrane has improved interfacial bonding with other materials bonded to the ion exchange membrane, so that long-term durability is maintained stably, and thus the bonding durability can be improved when applied to a power generation system as well as an energy storage device. In addition, the ion exchange membrane is also reduced in interfacial resistance with the other materials, thereby improving the through-plane exchange performance of the ion exchange membrane, it is possible to improve the efficiency of the system as well as bonding durability.

In addition, when the ion conductor is a hydrocarbon-based polymer including a benzene ring in the main chain and the ion exchange group is attached to the benzene ring, the fluorine may be substituted for the benzene ring by the fluorine gas treatment. In this case, as the substituted fluorine pulls electrons of the ion exchange group, the ion exchange group may have a weaker interaction with hydrogen ions, thereby improving ion conductivity of the ion exchange membrane. As described above, the hydrophilic region having the attraction force with the hydrogen ions of the ion conductor may be extremely hydrophilized and the hydrophobic region, which is the main chain including the benzene ring, may be extremely hydrophobic to improve the performance of the ion exchange membrane. Accordingly, even when the ion conductor is made of a material that does not contain fluorine, the surface treated with the fluorine gas of the ion conductor coating layer may include a very small amount (ppm) of fluorine.

The ion conductor made of a hydrocarbon-based polymer including a benzene ring in the main chain may be, for example, sulfonated polyimide (S-PI), sulfonated polyarylethersulfone (S-PAES). , Sulfonated polyetheretherketone (SPEEK), sulfonated polybenzimidazole (SPBI), sulfonated polysulfone (S-PSU) and mixtures thereof One selected may be mentioned, but the present invention is not limited thereto.

In addition, the ion exchange membrane may further include a fluorine-based ion conductor coating layer on the surface treated with fluorine gas of the ion conductor coating layer.

The fluorine-based ion conductor coating layer may be disposed between the other materials bonded to the ion exchange membrane and the ion exchange membrane to attach the ion exchange membrane to the material, and may act as a movement passage of fuel, ions or by-products. In particular, when the ion conductor filling the pores of the porous support is a hydrocarbon-based ion conductor, and the material to be bonded to the ion exchange membrane is an electrode including a fluorine-based ion conductor, the fluorine-based ion conductor coating layer may be formed of the ion exchange membrane and the electrode. It can arrange | position between them and can improve these joining further.

The thickness of the fluorine-based ion conductor coating layer may be 1 to 5 ㎛. When the thickness of the fluorine-based ion conductor coating layer is less than 1 μm, the adhesion of the ion exchange membrane may be weakened, and when the thickness of the fluorine ion conductor coating layer is greater than 5 μm, movement of fuel or the like may not be smooth.

The fluorine-based ion conductor coating layer may be formed of a fluorine-based ion conductor, and the fluorine-based ion conductor may be a fluorine-based polymer containing fluorine in the main chain described above, or a polystyrene-graft-ethylenetetrafluoroethylene copolymer, or a polystyrene- And partially fluorinated polymers such as graft-polytetrafluoroethylene copolymers.

More specifically, the fluorine-based ion conductor is a poly (perfluorosulfonic acid), poly (perfluorocarboxylic acid), a copolymer of tetrafluoroethylene and fluorovinyl ether containing a sulfonic acid group, defluorinated sulfide polyether Fluorine-based polymers including ketones or mixtures thereof, and commercially available Nafion (registered trademark) from Du Pont, Premion (registered trademark) from Asahi Glass, Inc. Perfluoro sulfonic acid systems, such as (trademark), etc. can be used.

Meanwhile, although the means for controlling the surface energy of the ion exchange membrane has been described, respectively, the present invention is not limited thereto, and the means for controlling the surface energy can be combined with each other.

For example, when the ion exchange membrane includes the silica coating layer, instead of the ion conductor coating layer, the surface of the silica coating layer includes a pattern in which a plurality of grooves are regularly or irregularly formed, or fine irregularities are formed to give a surface roughness. It may have, and also the surface of the silica coating layer may be fluorine gas treatment.

In addition, even when the surface of the ion conductor coating layer includes a pattern in which a plurality of grooves are regularly or irregularly formed or fine irregularities are formed to have a surface roughness, the surface of the ion conductor coating layer on which the pattern and the fine irregularities are formed is fluorine gas. It can also be processed.

According to another embodiment of the present invention, a method of manufacturing an ion exchange membrane includes mixing a silica dispersion and an ion conductor to prepare a silica-ion conductor mixture, and the silica on the surface of the porous support including a plurality of pores. Coating the ion conductor mixture to form a silica coating layer.

First, the silica dispersion and the ion conductor are mixed to prepare a silica-ion conductor mixture. The silica-ion conductor mixture may be prepared by adding the ion conductor to the silica dispersion and then adding an additional solvent.

Since the detailed description of the silica and the ion conductor is the same as described above, repeated description is omitted.

The silica dispersion may be used by purchasing a commercially available silica dispersion, or may be prepared by dispersing silica in a solvent. The silica dispersion may preferably be a silica nano dispersion, and the silica nano dispersion refers to a solution in which the silica is dispersed in nano size. Since the method of dispersing the silica in the solvent can be used a conventionally known method, a detailed description thereof will be omitted.

As the solvent for preparing the silica dispersion or the additional solvent, a solvent selected from the group consisting of water, a hydrophilic solvent, an organic solvent and a mixture of one or more thereof may be used.

The hydrophilic solvent is a group consisting of alcohols, isopropyl alcohols, ketones, aldehydes, carbonates, carboxylates, carboxylic acids, ethers, and amides containing, as main chain, linear, branched, saturated or unsaturated hydrocarbons having 1 to 12 carbon atoms. It may have one or more functional groups selected from, they may include an alicyclic or aromatic cyclo compound as at least part of the main chain.

The organic solvent can be selected from N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran and mixtures thereof.

Next, the silica-ion conductor mixture is coated on the surface of the porous support to form a silica coating layer.

Since the detailed description of the porous support is the same as described above, repeated description is omitted. However, the porous support may be prepared by a method selected from the group consisting of electroblowing, electrospinning, and melt blowing.

The silica-ion conductor mixture may be coated on the surface of the porous support using a screen printing method, a spray coating method, a doctor blade method, a laminating method, or the like, depending on the viscosity of the silica-ion conductor mixture.

Meanwhile, the forming of the silica coating layer may include filling the pores of the porous support with the silica-ion conductor mixture first, and forming the silica coating layer on the surface of the porous support.

To this end, the porous support may be supported or impregnated in the silica-ion conductor mixture. However, the present invention is not limited thereto, and even when the screen printing method, the spray coating method, the doctor blade method, the laminating method, and the like are used as described above, the silica-ion conductor mixture may be used to fill the pores of the porous support. It may be.

In addition, the porous support is supported or impregnated in the silica-ion conductor mixture so that the silica-ion conductor mixture first fills the pores of the porous support, and then sprays the silica-ion conductor mixture on the surface of the porous support. To form the silica coating layer.

Specifically, the impregnation method may be performed by immersing the porous support in the silica-ion conductor mixture. The impregnation temperature and time may be influenced by various factors. For example, it may be influenced by the thickness of the porous support, the concentration of the solution, the type of solvent and the like. However, the impregnation process may be carried out at a temperature of less than 100 ℃ at any point of the solvent, and more generally may be made for about 5 to 30 minutes at a temperature of 70 ℃ or less at room temperature (10 to 30 ℃). However, the temperature may not be higher than the melting point of the porous support. After the immersion can be dried for about 3 hours or more in a hot air oven about 80 ℃, such immersion, drying can be performed 2 to 5 times.

The forming of the silica coating layer may include filling the pores of the porous support with the ion conductor, and forming the silica coating layer by coating the silica-ion conductor mixture on the surface of the porous support. .

Filling the pores of the porous support with the ion conductor may be made by supporting or impregnating the porous support in a solution containing the ion conductor. However, the present invention is not limited thereto, and even when the screen printing method, the spray coating method, the doctor blade method, the laminating method, or the like is used, the solution containing the ion conductor may also fill the pores of the porous support. have.

The solution containing the ion conductor may be purchased by using a commercially available ion conductor solution, or may be prepared by dispersing the ion conductor in a solvent. Since the method for dispersing the ion conductor in a solvent can be used a conventionally known method, a detailed description thereof will be omitted.

As a solvent for preparing a solution including the ion conductor, a solvent selected from the group consisting of water, a hydrophilic solvent, an organic solvent, and one or more mixtures thereof may be used. Is omitted.

Specifically, the impregnation method may be performed by immersing the porous support in a solution containing the ion conductor. The impregnation temperature and time may be influenced by various factors. For example, it may be influenced by the thickness of the porous support, the concentration of the solution, the type of solvent and the like. However, the impregnation process may be performed at a temperature of 100 ° C. or less at any point of the solvent, and more generally, about 5 to 30 minutes at a temperature of 70 ° C. or less at room temperature (20 ° C.). However, the temperature may not be higher than the melting point of the porous support. After the immersion can be dried for about 3 hours or more in a hot air oven about 80 ℃, such immersion, drying can be performed 2 to 5 times.

Next, the silica coating layer is formed on the surface of the porous support in which the pores are filled with the ion conductor. The silica-ion conductor mixture may be coated on the surface of the porous support by using the above-mentioned screen printing method, spray coating method, doctor blade method, laminating method, or the like, or an impregnation method. Detailed description thereof is the same as described above, and thus repetitive description thereof will be omitted.

Method of manufacturing an ion exchange membrane according to another embodiment of the present invention comprises the steps of forming an ion conductor coating layer on the surface of the porous support while filling the pores of the porous support comprising a plurality of pores (pore) with an ion conductor, and Etching the surface of the ion conductor coating layer.

A detailed description of the porous support and the ion conductor and the method of filling the pores of the porous support with the ion conductor are the same as described above, and thus repetitive description thereof will be omitted.

However, in the process of filling the pores of the porous support with the ion conductor, the ion conductor fills the pores of the porous support, and forms the ion conductor coating layer on the surface of the porous support. To this end, the impregnation process may be performed several times.

Next, the surface of the ion conductor coating layer is etched. By the etching process, a pattern in which a plurality of grooves are regularly or irregularly formed on the surface of the ion conductor coating layer is formed, or fine irregularities are formed to have surface roughness.

The etching treatment may be a chemical treatment or a physical treatment.

The chemical treatment may be to use an organic solvent.

Specifically, the etching treatment may be performed by contacting an etching solution containing an organic solvent or an etching solution in which the ion conductor is diluted in the organic solvent, on the surface of the ion conductor coating layer.

The organic solvent is N-methyl-2-pyrrolidone (N-methyl-2-pyrrolidine, NMP), dimethylformamide (dimethylformamide, DMF), dimethyl acetamide (dimethylacetamide, DMAc), dimethyl sulfoxide (dimethylsulfoxide, DMSO ) And mixtures thereof.

The etching solution may include 0 to 3% by weight of the ion conductor relative to the total weight of the etching solution. When the etching solution further includes the ion conductor, the polymer electrolyte membrane formed as a thin film is preferable in that the performance may be reduced due to etching, and the content of the ion conductor is 3 based on the total weight of the etching solution. If it exceeds the weight% may be converted to the direction in which the coating layer of the silica nanodispersant and the ion conductor is formed rather than the meaning of etching may cause a problem that the effect of etching is inhibited.

In addition, the silica dispersion for forming the silica coating layer as the etching solution may be used as the etching solution. Since the detailed description of the silica dispersion is the same as described above, repeated description is omitted. When the silica dispersion is used as the etching solution, an effect of increasing the surface area or further reducing the surface energy of the film may be generated.

The etching process may be performed by spraying the etching solution on the surface of the ion conductor coating layer, the intensity of the spray can be appropriately adjusted according to the size of the fine unevenness to be formed, for example, the etching treatment is the etching The solution may be made by contacting the surface of the ion conductor coating layer in an amount of 0.05 to 1 ml / cm ² . If the etching solution treatment is less than 0.05 ml / cm ² may cause a problem that the etching effect hardly occurs, and if it exceeds 1 ml / cm ² may cause a problem of washing off the polymer coating layer to peel off.

The physical treatment may be any one selected from the group consisting of laser irradiation, polishing, corona treatment, plasma treatment, and the like, wherein the polishing rubs sandpaper or nip roll cloth with an appropriate strength to form a desired fine unevenness. It can be made to.

In addition, when the etching process is used to form a pattern on the surface of the ion conductor coating layer, the chemical treatment or the physical treatment may be performed using a mask having a pattern shape to be formed.

Method of manufacturing an ion exchange membrane according to another embodiment of the present invention comprises the steps of forming an ion conductor coating layer on the surface of the porous support while filling the pores of the porous support comprising a plurality of pores (pore) with an ion conductor, and Treating the surface of the ion conductor coating layer with fluorine gas.

A detailed description of the porous support and the ion conductor and the method of filling the pores of the porous support with the ion conductor are the same as described above, and thus repetitive description thereof will be omitted.

However, in the process of filling the pores of the porous support with the ion conductor, the ion conductor fills the pores of the porous support, and forms the ion conductor coating layer on the surface of the porous support. To this end, the impregnation process may be performed several times.

Next, the surface of the ion conductor coating layer is treated with fluorine gas.

The surface treated with fluorine gas of the ion conductor coating layer by the fluorine gas treatment may include a covalent bond and a fluorine substituent.

The fluorine gas treatment may be performed by blowing fluorine gas in several ppm units in a chamber at room temperature (10 to 30 ° C.). The fluorine gas treatment time may be about 5 to 60 minutes, and when the fluorine gas treatment is performed within the treatment time, about 10 to 40 area% of the surface of the ion conductor coating layer may change surface properties.

The method of manufacturing the ion exchange membrane may further include forming a fluorine-based ion conductor coating layer on the fluorine gas treated ion conductor coating layer.

Since the detailed description of the fluorine-based ion conductor coating layer is the same as described above, repeated description is omitted.

In addition, a solution containing the fluorine ion conductor for forming the fluorine ion conductor coating layer may be purchased by using a solution containing a fluorine ion conductor commercially available in the same manner as the ion conductor, and the fluorine ion conductor is dispersed in a solvent It can also make it. Since the method for dispersing the fluorine-based ion conductor in the solvent can be used a conventionally known method, a detailed description thereof will be omitted.

In addition, a solvent selected from the group consisting of water, a hydrophilic solvent, an organic solvent, and a mixture of one or more thereof may be used as a solvent for preparing a solution including the fluorine-based ion conductor, and the same as described above. Repeated explanations are omitted.

As a method of coating the solution containing the fluorine-based ion conductor on the fluorine gas-treated ion conductor coating layer, a screen printing method, a spray coating method, a doctor blade method, a laminating method, or the like may be used.

On the other hand, the respective methods for producing the ion exchange membrane have been described, but the present invention is not limited thereto, and the method for producing the ion exchange membrane can be combined with each other.

For example, when the method of manufacturing the ion exchange membrane includes forming the silica coating layer, the surface of the silica coating layer may be etched or fluorine gas treated in place of the ion conductor coating layer, or the The surface of the silica coating layer may be etched after the etching process, and the surface of the silica coating layer may be etched after the fluorine gas treatment.

In addition, the surface of the ion conductor coating layer may be etched after the etching process, the surface of the ion conductor coating layer may be etched after the fluorine gas treatment.

Energy storage device according to another embodiment of the present invention includes the ion exchange membrane. Hereinafter, a case where the energy storage device is a redox flow battery or a fuel cell will be described in detail. However, the present invention is not limited thereto, and the ion exchange membrane may be applied to an energy storage device having a secondary battery type.

In one example of the energy storage device, the ion exchange membrane has low vanadium ion permeability by blocking vanadium ions due to small ion channels, so that the vanadium active material crossovers when applied to a vanadium redox flow cell. It is possible to achieve a high energy efficiency by solving the problem of lowering the energy efficiency, the energy storage device may be preferably a redox flow battery (redox flow battery).

The redox flow battery may be charged and discharged by supplying a positive electrode electrolyte and a negative electrode electrolyte to a battery cell including a positive electrode and a negative electrode disposed to face each other and the ion exchange membrane disposed between the positive electrode and the negative electrode.

The redox flow battery includes an all-vanadium redox battery using a V (IV) / V (V) redox couple as a cathode electrolyte and a V (II) / V (III) redox couple as a cathode electrolyte; Vanadium-based redox cells using a halogen redox couple as a positive electrode and a V (II) / V (III) redox couple as a negative electrolyte; Polysulfidebromine redox cells using a halogen redox couple as the positive electrolyte and a sulfide redox couple as the negative electrolyte; Or a zinc-bromine (Zn-Br) redox battery using a halogen redox couple as a cathode electrolyte and a zinc (Zn) redox couple as a cathode electrolyte, but the type of the redox flow battery in the present invention It is not limited.

Hereinafter, the case where the redox flow battery is an all-vanadium redox battery will be described as an example. However, the redox flow battery of the present invention is not limited to the all vanadium-based redox battery.

1 is a schematic diagram schematically showing the all-vanadium redox battery.

Referring to FIG. 1, the redox flow battery includes a cell housing 102, the ion exchange membrane 104 installed to bisect the cell housing 102 into a positive cell 102A and a negative cell 102B, and the A positive electrode 106 and a negative electrode 108 positioned in each of the positive cell 102A and the negative cell 102B are included.

In addition, the redox flow battery may further include a cathode electrolyte storage tank 110 in which the cathode electrolyte is stored and a cathode electrolyte storage tank 112 in which the anode electrolyte is stored.

In addition, the redox flow battery includes a cathode electrolyte inlet and a cathode electrolyte outlet at the top and bottom of the cathode cell 102A, and includes a cathode electrolyte inlet and a cathode electrolyte outlet at the top and bottom of the cathode cell 102B. can do.

The anode electrolyte stored in the cathode electrolyte storage tank 110 flows into the cathode cell 102A through the anode electrolyte inlet by a pump 114 and then from the cathode cell 102A through the anode electrolyte outlet. Discharged.

Similarly, the negative electrolyte stored in the negative electrolyte storage tank 112 flows into the negative cell 102B through the negative electrolyte inlet by a pump 116, and then through the negative electrolyte outlet 102 through the negative electrolyte outlet. Is discharged from

In the anode cell 102A, the movement of electrons through the anode 106 occurs according to the operation of the power supply / load 118, and thus an oxidation / reduction reaction of V ⁵⁺ ↔ V ⁴⁺ occurs. Similarly, in the cathode cell 102B, the movement of electrons through the cathode 108 occurs according to the operation of the power source / load 118, and thus, an oxidation / reduction reaction of V ²⁺ ↔ V ³⁺ occurs. After the oxidation / reduction reaction, the positive electrolyte and the negative electrolyte are circulated to the positive electrolyte storage tank 110 and the negative electrolyte storage tank 112, respectively.

The anode 106 and the cathode 108 are Ru, Ti, Ir. A composite material (e.g., a Ti base material) comprising an oxide of at least one metal selected from Mn, Pd, Au, and Pt, and an oxide of at least one metal selected from Ru, Ti, Ir, Coated with Ir oxide or Ru oxide), carbon composite containing the composite material, dimensionally stable electrode (DSE) containing the composite material, conductive polymer (for example, electrically conductive polymer such as polyacetylene, polythiophene, etc.) Material), graphite, glassy carbon, conductive diamond, conductive DLC (Diamond-Like Carbon), a nonwoven fabric made of carbon fiber, and a woven fabric made of carbon fiber.

The positive electrode electrolyte and the negative electrode electrolyte may include any one metal ion selected from the group consisting of titanium ions, vanadium ions, chromium ions, zinc ions, tin ions, and mixtures thereof.

For example, the negative electrolyte includes vanadium divalent ions (V ²⁺ ) or vanadium trivalent ions (V ³⁺ ) as negative electrolyte ions, and the positive electrolyte includes vanadium tetravalent ions (V ⁴⁾ as positive electrolyte ions. ⁺ ) Or vanadium ^pentavalent ions (V ⁵⁺ ).

The concentration of the metal ions included in the cathode electrolyte and cathode electrolyte is preferably 0.3 to 5 M.

The solvent of the cathode electrolyte and the cathode electrolyte is H ₂ SO ₄ , K ₂ SO ₄ , Na ₂ SO ₄ , H ₃ PO ₄ , H ₄ P ₂ O ₇ , K ₂ PO ₄ , Na ₃ PO ₄ , K ₃ PO Any one selected from the group consisting of ₄ , HNO ₃ , KNO ₃ and NaNO ₃ can be used. Since the metal ions serving as the positive electrode and the negative electrode active material are all water soluble, an aqueous solution can be suitably used as a solvent of the positive electrode electrolyte and the negative electrode electrolyte. In particular, when using any one selected from the group consisting of sulfuric acid, phosphoric acid, nitric acid, sulfate, phosphate and nitrate as the aqueous solution, it is possible to improve the stability, reactivity and solubility of the metal ion.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

[ Example Ion Exchange membrane  Produce]

( Example  1-1)

The polyamic acid / THF spinning solution having a concentration of 12% by weight was electrospun in a state where a voltage of 30 kV was applied, and then a polyamic acid nanoweb precursor was formed, followed by heat treatment in an oven at 350 ° C. for 5 hours to obtain 15 μm. A polyimide porous support having an average thickness was prepared. At this time, the electrospinning was carried out in a state in which a voltage of 30 kW was applied in a spray jet nozzle at 25 ℃.

A 10 wt% ion conductor solution was prepared by dissolving sulfonated polyetheretherketone (SPEEK) in N-methyl-2-pyrrolidinone (NMP).

The porous support was immersed in the ion conductor solution. Specifically, the immersion process was performed at room temperature for 20 minutes, and a reduced pressure atmosphere was applied for about 1 hour to remove fine bubbles. Thereafter, the mixture was dried in a hot air oven maintained at 80 ° C. for 3 hours to remove NMP.

Meanwhile, a silica-ion conductor mixture was prepared by dissolving a sulfonated polyetheretherketone (SPEEK) as an ion conductor in a silica dispersion (silica particle diameter of 15 nm, solvent isopropyl alcohol, and silica 25 wt%). The silica-ion conductor mixture contained 10 parts by weight of the silica with respect to 100 parts by weight of the ion conductor.

A porous support filled with voids in the ion conductor was immersed in the silica-ion conductor mixture. Specifically, an immersion process was performed at room temperature for 20 minutes, and a reduced pressure atmosphere was applied for about 1 hour to remove fine bubbles. Thereafter, the mixture was dried in a hot air IR oven maintained at 80 ° C. for 3 hours to remove NMP, thereby preparing an ion exchange membrane.

( Example  1-2)

An etching solution was prepared by diluting an ion conductor, SPEEK (sulfonated polyetheretherketone), in an organic solvent, DMAc. In this case, the etching solution includes the ion conductor as 3% by weight based on the total weight of the etching solution.

The prepared etching solution was sprayed on the surface of the ion exchange membrane prepared in Example 1-1 at an amount of 0.1 ml / cm ² at room temperature, and dried and etched in a hot air IR oven maintained at 80 ° C. On the surface of the prepared ion conductor, fine irregularities of 3% by length with respect to the entire thickness of the silica coating layer were formed.

( Example  1-3)

In Example 1-2, an ion exchange membrane was manufactured in the same manner as in Example 1-2, except that the prepared ion exchange membrane was physically passed through a nip roll instead of the etching treatment with the etching solution. It was. On the surface of the prepared silica coating layer, 5 length% fine unevenness was formed with respect to the entire thickness of the silica coating layer.

( Example  1-4)

In Example 1-2, except that the stripe pattern having a width of 100 nm and an interval of 100 nm on the surface of the silica coating layer by a plasma treatment method instead of etching with the organic solvent, Example 1-2 In the same manner as in the ion exchange membrane was prepared.

( Example  1-5)

In Example 1-2, Example 1- except that 10 ppm fluorine gas was treated for 60 minutes in a chamber at room temperature with respect to the 10X10 cm ² ion exchange membrane instead of etching with the organic solvent. It carried out similarly to 2, and manufactured the ion exchange membrane.

( Example  2-1)

The polyamic acid / THF spinning solution having a concentration of 12% by weight was electrospun in a state where a voltage of 30 kV was applied, and then a polyamic acid nanoweb precursor was formed, followed by heat treatment in an oven at 350 ° C. for 5 hours to obtain 15 μm. A polyimide porous support having an average thickness was prepared. At this time, the electrospinning was carried out in a state in which a voltage of 30 kW was applied in a spray jet nozzle at 25 ℃.

A 20 wt% ion conductor solution was prepared by dissolving sulfonated polyetheretherketone (SPEEK) in N-methyl-2-pyrrolidinone (NMP).

The porous support was immersed in the ion conductor solution. Specifically, the immersion process was performed at room temperature for 20 minutes, and a reduced pressure atmosphere was applied for about 1 hour to remove fine bubbles. Thereafter, the mixture was dried in a hot air oven maintained at 80 ° C. for 3 hours to remove NMP. The immersion and drying process was repeated three times to prepare an ion exchange membrane.

Meanwhile, an etching solution was prepared by diluting an ion conductor SPEEK (sulfonated polyetheretherketone) in an organic solvent DMAc. In this case, the etching solution includes the ion conductor as 3% by weight based on the total weight of the etching solution.

The prepared etching solution was sprayed on the surface of the prepared ion exchange membrane at an amount of 0.1 ml / cm ² at room temperature, and then dried and etched in a hot air IR oven maintained at 80 ° C. On the surface of the prepared ion conductor, fine unevenness of 1% by length with respect to the total thickness of the ion conductor coating layer was formed.

( Example  2-2)

In Example 2-1, an ion exchange membrane was manufactured in the same manner as in Example 2-1, except that the prepared ion exchange membrane was physically passed through a nip roll instead of the etching treatment with the etching solution. It was. On the surface of the prepared ion exchange membrane, fine lengths of 5% by length of the total thickness of the ion conductor coating layer were formed.

( Example  2-3)

In Example 2-1, except that the stripe pattern having a width of 100 nm and an interval of 100 nm was formed on the surface of the ion conductor coating layer by plasma treatment instead of etching with the organic solvent. It carried out similarly to 1, and manufactured the ion exchange membrane.

( Example  3)

In Example 2-1, except that 10 ppm fluorine gas was treated for 60 minutes in a chamber at room temperature with respect to the 10X10 cm ² sized ion exchange membrane instead of etching with the organic solvent, Example 2- It carried out similarly to 1, and manufactured the ion exchange membrane.

[ Experimental Example  1: ion Exchange membrane  Ion conductivity]

The Pt / C electrodes were fixed on both sides of the ion exchange membrane prepared in the above example, and the through plane hydrogen ion conductivity was measured at 95% RH and 80 ° C., and the results are shown below.

	Hydrogen ion conductivity (S / cm)
Example 1-1	0.05
Example 1-2	0.08
Example 1-3	0.06
Example 1-4	0.07
Example 1-5	0.09
Example 2-1	0.04
Example 2-2	0.06
Example 2-3	0.06
Example 3	0.07

As shown in Table 1 above, the ion exchange membranes of Examples 1-1 to 3 showed high hydrogen ion conductivity of 0.04 to 0.09 S / cm.

[ Experimental Example  2: ion Exchange membrane  Surface energy]

The surface energy of the ion exchange membrane prepared in the above example was evaluated by measuring the contact angle with respect to water, and the results are shown below.

	Contact angle (°)
Example 1-1	63
Example 1-2	60
Example 1-3	70
Example 1-4	65
Example 1-5	70
Example 2-1	80
Example 2-2	75
Example 2-3	70
Example 3	75

As a result of Table 2, the contact angles of Examples 1-1 to 3 including the silica coating layer having a low surface energy, or the surface etching treatment, the patterning process, and the fluorine gas were all 60 ° or more, and the average As high as 69 ° or more.

As described above, it was confirmed that the surface energy of the ion exchange membrane was controlled to reduce the interface resistance by the preferred embodiment of the present invention. In addition, it was confirmed that the interface bonding property was improved by controlling the surface energy of the ion exchange membrane.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

In the case of an energy storage device including an ion exchange membrane according to an exemplary embodiment of the present invention, particularly a redox flow battery, a load leveling function capable of responding to a sudden increase in power demand by installing in a power plant, a power system, or a building, a power failure or an instantaneous low voltage It is suitable for large-scale energy storage because it has the function to compensate or suppress the

Claims (26)

1. A porous support comprising a plurality of pores,

   An ion conductor filling the pores of the porous support, and

   A silica coating layer located on the surface of the porous support and comprising silica and an ion conductor

   Ion exchange membrane comprising a.
2. The method of claim 1,

   The pores of the porous support further comprises silica mixed with the ion conductor.
3. The method of claim 2,

   Based on 100 parts by weight of silica included in the silica coating layer,

   Silica contained in the pores of the porous support is 10 parts by weight or less.
4. The method of claim 1,

   The surface of the silica coating layer is ion exchange membrane that comprises a pattern in which a plurality of grooves are formed regularly or irregularly.
5. The method of claim 1,

   The surface of the silica coating layer is fine ion irregularities are formed to have a surface roughness ion exchange membrane.
6. The method of claim 1,

   The surface of the silica coating layer is an ion exchange membrane comprising a surface treated with fluorine gas.
7. A porous support comprising a plurality of pores, and

   Filling the pores of the porous support comprises an ion conductor to form an ion conductor coating layer on the surface of the porous support,

   The surface of the ion conductor coating layer is ion exchange membrane comprising a pattern in which a plurality of grooves are formed regularly or irregularly.
8. A porous support comprising a plurality of pores, and

   Filling the pores of the porous support and comprises an ion conductor to form an ion conductor coating layer on the surface of the porous support,

   The surface of the ion conductor coating layer is an ion exchange membrane that has a surface roughness is formed fine irregularities.
9. The method of claim 8,

   The size of the fine irregularities is 0.1 to 20% by length based on the total thickness of the ion conductor coating layer.
10. A porous support comprising a plurality of pores, and

    Filling the pores of the porous support and comprises an ion conductor to form an ion conductor coating layer on the surface of the porous support,

    And the ion conductor coating layer comprises a surface treated with fluorine gas.
11. The method of claim 10,

    The ion conductor is a hydrocarbon-based polymer whose main chain includes a benzene ring and an ion exchange group is attached to the benzene ring,

    The surface treated with the fluorine gas of the ion conductor coating layer is a fluorine-substituted fluorine-substituted by the fluorine gas treatment.
12. The method of claim 10,

    And an fluorine-based ion conductor coating layer on the surface treated with the fluorine gas of the ion conductor coating layer.
13. The method according to any one of claims 1, 7, 8 and 10,

    The porous support is a hydrocarbon-based porous support,

    The ion conductor is an ion exchange membrane that is a hydrocarbon-based ion conductor.
14. Mixing the silica dispersion with the ion conductor to prepare a silica-ion conductor mixture, and

    Coating the silica-ion conductor mixture on the surface of the porous support including a plurality of pores to form a silica coating layer

    Method for producing an ion exchange membrane comprising a.
15. The method of claim 14,

    Forming the silica coating layer

    The silica-ion conductor mixture forms the silica coating layer on the surface of the porous support while filling the pores of the porous support.

    Method for producing an ion exchange membrane.
16. The method of claim 14,

    Forming the silica coating layer

    Filling the pores of the porous support with an ion conductor, and

    Coating the silica-ion conductor mixture on a surface of the porous support to form the silica coating layer

    Method for producing an ion exchange membrane comprising a.
17. The method of claim 14,

    After the step of forming the silica coating layer, the method of producing an ion exchange membrane further comprising the step of etching the surface of the silica coating layer.
18. The method of claim 14,

    After forming the silica coating layer, the method of manufacturing an ion exchange membrane further comprising the step of treating the surface of the silica coating layer with fluorine gas.
19. Forming an ion conductor coating layer on the surface of the porous support while filling the pores of the porous support including a plurality of pores with the ion conductor, and

    Etching the surface of the ion conductor coating layer

    Method for producing an ion exchange membrane comprising a.
20. The method of claim 19,

    The etching process is performed by contacting the surface of the ion conductor coating layer with an etching solution selected from the group consisting of an etching solution containing an organic solvent, an etching solution in which an ion conductor is diluted with an organic solvent, and a silica dispersion. Method of producing an exchange membrane.
21. The method of claim 19,

    The etching process is a method for producing an ion exchange membrane, which is performed by any one of a physical treatment selected from the group consisting of laser irradiation, polishing, corona treatment and plasma treatment.
22. Forming an ion conductor coating layer on the surface of the porous support while filling the pores of the porous support including a plurality of pores with the ion conductor, and

    Treating the surface of the ion conductor coating layer with fluorine gas

    Method for producing an ion exchange membrane comprising a.
23. The method of claim 22,

    And forming a fluorine-based ion conductor coating layer on the fluorine-gas treated ion conductor coating layer.
24. An energy storage device comprising the ion exchange membrane according to any one of claims 1, 7, 8 and 10.
25. The method of claim 24,

    The energy storage device is a fuel cell.
26. The method of claim 24,

    The energy storage device is a redox flow battery (redox flow battery).

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