KR20190095163A - Transparent Electrode and Metal Air Secondary Batteries containing the same - Google Patents

Abstract

The present invention relates to a transparent electrode and a metal-air secondary battery comprising the same. The electrode may provide a passage through which light can pass while ensuring electrical insulation between electrodes because the electrode is flexible including a metal mesh and have a thin film formed along a metal line which forms the metal mesh and contains the metal mesh with an anion exchange resin which functions as a separator on one surface of the metal mesh. Accordingly, since the transparent electrode does not require a separate separator and has excellent light transmittance, an electronic device including same, especially the metal-air secondary battery, has excellent charge and discharge characteristics, is flexible and thin, and has excellent light transmittance.

Description

Transparent electrode and metal-air secondary battery comprising same

The present invention relates to a transparent electrode and a metal-air secondary battery comprising the same.

Augmented reality (AR) is an important topic of interest in the field of electronics, and efforts to apply it to real life have been diversified. However, in order to apply a technology such as augmented reality to real life, the system to which it is applied should be able to supply a high power of its own and meet high flexibility and light transmittance, but it is difficult to satisfy it. In fact, in order to supply power to a high-power device to which augmented reality is applied, a transparent battery such as a lithium ion battery has been developed in the related art. However, since the lithium ion battery has a small charge / discharge cycle and exhibits limited charge and discharge characteristics, the life of the device is long. There is a short limit.

On the other hand, since the zinc-air secondary battery uses oxygen in the air, a relatively large amount of zinc can be filled in the negative electrode, and thus the energy density per mass unit is high. Therefore, the zinc-air secondary battery is characterized by a very large charge / discharge capacity even if its size is small, and the voltage is kept constant until the battery capacity is exhausted due to the low self discharge. In addition, zinc oxide generated during the electricity generation is less toxic or explosion risk, there is an environmentally friendly advantage because it uses abundant zinc and air on the earth.

To date, in order to further improve the lifespan of zinc-air secondary batteries, techniques for improving reversibility of zinc electrodes or preventing loss of electrolytes have been studied. However, as described above, the technology for improving light transmittance or flexibility required for use in a device such as a system using augmented reality has not been studied. Therefore, a zinc-air secondary battery capable of satisfying light transmittance and flexibility at the same time has been studied. There is a demand for technology development.

Republic of Korea Patent Publication 2016-0009872

An object of the present invention is to provide a zinc-air secondary battery that is excellent in charge and discharge characteristics, as well as excellent in light transmittance and flexibility.

The present invention to solve the above problems in one embodiment

Metal mesh; And

A thin film located on one surface of the metal mesh and including an ion exchange resin,

The thin film is formed along a metal line included in the metal mesh to provide a transparent electrode having a structure including pores.

In addition, the present invention in one embodiment

Laminating a metal mesh on the partially dried ion exchange resin;

Immersing the ion exchange resin in which the metal mesh is laminated in a hydroxide solution; And

Desorbing the metal mesh from the immersed ion exchange resin, to provide a method for producing a transparent electrode comprising the step of obtaining a transparent electrode having a thin film formed along a metal wire on one surface of the metal mesh.

Further, the present invention in one embodiment,

An air electrode including the transparent electrode;

A zinc electrode comprising a metal mesh containing zinc (Zn); And

A zinc-air secondary battery comprising an electrolyte gel containing hydroxide ions is provided.

Since the transparent electrode according to the present invention is flexible including a metal mesh, and a thin film that functions as a separator on one surface of the metal mesh is formed along a metal line constituting the metal mesh to have pores, the electrical insulation between the electrodes Can provide a passage through which light can pass. Therefore, since the transparent electrode does not require a separate separator and has excellent light transmittance, an electronic device including the same, particularly a metal-air secondary battery, has not only excellent charge and discharge characteristics, but also flexibility, thinness, and an excellent light transmittance. There is this.

1 is a schematic view showing the structure of a zinc-air secondary battery according to the present invention.
2 is a flowchart illustrating a manufacturing process of a cathode and a zinc electrode provided in the zinc-air secondary battery according to the present invention.
Figure 3 is an optical microscope image of the appearance of the metal wire by the amount of the coated active material of the transparent electrode and the zinc electrode according to the present invention.
Figure 4 is an image showing a transparent electrode according to the present invention: (a) a photograph taken of the surface with an optical microscope, (b) an image taken with a field emission-scanning electron microscope (FE-SEM), (c) Image taken with a field emission-scanning electron microscope (FE-SEM).
FIG. 5 illustrates 400 of a transparent electrode having a structure in which (a) a transparent electrode having a thin film containing an anion exchange resin on one surface of a metal mesh and (b) a thin film containing an anion exchange resin on one surface of a metal mesh is stacked. It is a graph showing the light transmittance with respect to light of nm to 700 nm wavelength.
6 I and II are graphs showing light transmittance in the wavelength range of 400 nm to 700 nm, and III and IV are photographs taken with a camera of the assembled zinc-air secondary battery: (a) untreated stainless steel Mesh, (b) zinc electrode, (c) air electrode and (d) assembled zinc-air secondary battery.
FIG. 7 shows Ohmic resistance of a zinc electrode coated with (a) a zinc electrode electrodeposited with zinc (Zn) on a metal mesh and (b) a polymer composition in which zinc (Zn) powder is dispersed on a metal mesh. The graph shown.
FIG. 8 is an ohmic of a transparent electrode having a structure in which (a) a transparent electrode having a thin film containing an anion exchange resin on one surface of a metal mesh and (b) a thin film containing an anion exchange resin on one surface of a metal mesh is laminated It is a graph showing Ohmic resistance.
9 is a graph showing (II) the number of charge and discharge, (III) current density and (IV) ohmic resistance according to (I) bending angle of the zinc-air secondary battery according to the present invention.
10 is an image using a zinc-air secondary battery according to the present invention as a light emitting diode (LED) power source.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description.

However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

In the present invention, the terms "comprises" or "having" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

In addition, it is to be understood that the accompanying drawings in the present invention are shown to be enlarged or reduced for convenience of description.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, and the same or corresponding components will be given the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted.

The present invention relates to a transparent electrode and a zinc-air secondary battery comprising the transparent electrode.

Since zinc-air secondary batteries use oxygen in the air, a relatively large amount of zinc can be filled in the negative electrode, and thus the energy density per mass unit is high, thus showing a large charge / discharge capacity even at a small size. It is advantageous to keep it. In addition, since zinc used as an active material is abundantly present on the earth, it is economical, and zinc oxide generated during electricity generation has little toxicity or explosion risk, and efforts to use it as a high power battery have been continued. In particular, in order to be applied to a system to which augmented reality (AR) is applied, not only excellent charge and discharge characteristics, but also require high light transmittance and flexibility, but it is still difficult to find a secondary battery that satisfies these properties.

Accordingly, the present invention provides a transparent electrode and a zinc-air secondary battery including the transparent electrode.

Since the transparent electrode according to the present invention is flexible including a metal mesh, and a thin film that functions as a separator on one surface of the metal mesh is formed along a metal line constituting the metal mesh to have pores, the electrical insulation between the electrodes Can provide a passage through which light can pass. Therefore, since the transparent electrode does not require a separate separator and has excellent light transmittance, an electronic device including the same, particularly a metal-air secondary battery, has not only excellent charge and discharge characteristics, but also flexibility, thinness, and an excellent light transmittance. There is this.

Hereinafter, the present invention will be described in more detail.

Transparent electrode

In one embodiment of the invention,

Metal mesh; And

A thin film located on one surface of the metal mesh and including an ion exchange resin,

The thin film is formed along a metal line included in the metal mesh to provide a transparent electrode having a structure including pores.

The transparent electrode according to the present invention includes a metal mesh and a thin film positioned on one surface of the metal mesh. Here, the metal mesh may perform a function of structurally giving flexibility to the transparent electrode. The metal mesh is not particularly limited as long as it can function as a current collector of the transparent electrode, but a stainless steel mesh, a gold mesh, a silver mesh, or a copper mesh may be used in consideration of mechanical properties such as ductility of the electrode.

In addition, the metal mesh may be composed of a metal wire having a predetermined thickness and have a predetermined porosity to satisfy both electrical and optical properties as well as mechanical properties of the electrode. For example, the average thickness of the metal wire constituting the metal mesh may be 1 μm to 100 μm, more specifically 1 μm to 80 μm, 1 μm to 60 μm, 1 μm to 40 μm, and 1 μm to 20 Μm, 1 μm to 10 μm, 20 μm to 80 μm, 40 μm to 60 μm, 50 μm to 80 μm, 5 μm to 40 μm, 10 μm to 50 μm, 15 μm to 50 μm¸ 20 μm to 50 μm, 25 μm to 50 μm, 10 μm to 40 μm, 10 μm to 25 μm, 20 μm to 40 μm, or 25 μm to 35 μm. In addition, the porosity of the metal mesh may be 60% to 95%, more specifically 60% to 85%, 60% to 75%, 70% to 95%, 80% to 95%, 70% to 85% Or 74% to 83%.

As one example, the transparent electrode may be woven into a stainless steel wire having an average diameter of 30 ± 2 ㎛ to include a mesh having a porosity of 78 ± 2%.

Furthermore, the metal mesh may include a coating layer on the surface including an active material and / or a catalyst, depending on the use of the transparent electrode. As an example, the metal mesh may include a coating layer including a catalyst including at least one metal selected from the group consisting of platinum (Pt), iridium (Ir), cobalt (Co), and manganese (Mn) or an oxide thereof. It can be provided.

In addition, the transparent electrode may include a thin film formed on one surface of a metal mesh by ion-exchange resin being fed into the mesh along a metal line. The thin film is dried in a state in which an ion exchange resin is fed with metal wires on one side of the metal mesh by surface tension, and is formed along the structure of the metal mesh to be the same position as the opening of the metal mesh (that is, the pores of the metal mesh). Since pores are included in the path, light may pass through the electrode, thereby inducing insulation to the metal mesh like the separator.

The thin film may be an anion exchange resin comprising at least one functional group selected from the group consisting of quaternary ammonium groups, iminoacetic acid groups, and thiourea groups. As one example, the thin film may be an anion exchange resin comprising a chemical structure in which a quaternary ammonium group is bonded to an aromatic ring.

In addition, the thickness of the thin film may be different depending on the surface structure of the metal mesh since the ion exchange resin is dried along the structure of the metal mesh, and the average thickness may provide a high level of light transmittance of the electrode while appropriately providing insulation to the metal mesh. It may be 1 to 15 ㎛, or 5 ㎛ to 10 ㎛ to maintain. Specifically, since the metal mesh has a structure in which the metal wire is woven, the metal wire in the horizontal position alternates up and down the metal wire in the vertical position. As a result, the thin film bottled and dried on one surface of the metal mesh may have a different thickness depending on a direction in which the metal line in the horizontal position proceeds based on the metal line in the vertical position.

As an example, referring to FIG. 4, the thin film may have a thickness of about 13 ± 0.5 μm when the metal line in the horizontal position is advanced above the metal line in the vertical position, and the metal line may be below the metal line in the vertical position. It may have a thickness of about 3 ± 0.5 μm, so the average thickness may be about 8 ± 0.5 μm.

The transparent electrode according to the present invention has not only excellent electrical properties and excellent flexibility and light transmittance by having the above configuration, but also a touch panel, a light emitting glass, a light emitting device, a solar cell as well as a secondary battery such as a metal-air secondary battery. The electrode may be used as an electrode of a transistor, and the electronic devices may be those generally known in the art.

Method of manufacturing a transparent electrode

In addition, the present invention in one embodiment,

Laminating a metal mesh on the partially dried ion exchange resin;

Immersing the ion exchange resin in which the metal mesh is laminated in a hydroxide solution; And

It provides a method for producing a transparent electrode comprising the step of desorbing the metal mesh from the immersion ion exchange resin to obtain a transparent electrode having a thin film on one surface of the metal mesh.

The method for manufacturing a transparent electrode according to the present invention is included in a process of forming a thin film on which a ion exchange resin is dried along a metal line included in a metal mesh.

Specifically, the manufacturing method is applied to the ion exchange resin on a polymer substrate such as polyethylene terephthalate, and partially dried to about 50% to 80%, specifically 60% to 75%, and then partially After laminating and drying the metal mesh on the dried ion exchange resin and drying it, the metal wire included in the metal mesh is immersed in the hydroxide solution for a predetermined time, and the immersed ion exchange resin is removed from the hydroxide solution and the metal mesh is desorbed from the ion exchange resin. Accordingly, a transparent electrode including a thin film in which the ion exchange resin is bottled and dried can be manufactured.

Here, the metal mesh laminated on the partially dried ion exchange resin may be recessed in part or all of one side of the metal mesh into the partially dried ion exchange resin without the force (external force) applied from the outside.

Further, in the step of immersing the ion exchange resin in which the metal mesh is laminated in the hydroxide solution, the hydroxide solution induces the ion exchange resin to be fed into the metal mesh by the surface tension of the resin, while the ion exchange resin when the metal mesh is desorbed. The metal mesh may serve to distinguish and separate between the recessed and non-dented regions. As an example, when the metal mesh laminated ion exchange resin is immersed in a hydroxide solution, and then the metal mesh is desorbed, the area recessed in the metal wire of the metal mesh remains in the form of a bottled dry ion exchange resin and is recessed in the metal wire. The pore portion of the non-metal mesh is free of ion exchange resins; If the metal mesh is desorbed without being immersed in the hydroxide solution, the dried ion exchange resin may be damaged and completely separated from the metal mesh.

Such hydroxide solution may include one or more selected from the group consisting of NaOH, KOH, Mg (OH) ₂ , Ca (OH) ₂ and Ba (OH) ₂ , wherein the concentration is 0.01M to 5M. For example, it may be 0.01M to 4M, 0.01M to 2M, 0.01M to 1M, 0.01M to 0.5M, 0.01M to 0.3M, 0.01M to 0.2M, or 0.05M to 0.15M. In addition, the time to be immersed in the hydroxide solution may be 10 hours to 50 hours, specifically 12 hours to 48 hours, 16 hours to 36 hours, 20 hours to 30 hours, or 22 hours to 26 hours.

On the other hand, the metal mesh is a group consisting of platinum (Pt), iridium (Ir), cobalt (Co) and manganese (Mn) before the step of laminating on the partially dried ion exchange resin according to the use of the transparent electrode Coating a surface with a composition comprising a catalyst and a catalyst comprising at least one metal selected from can be performed.

In addition, the coating step is an air brush, Mayer, D-bar, rubber roll, G / V roll (G / V roll) useful for coating the liquid composition , Air knife, slot die, or the like.

As an example, when the transparent electrode is used as the cathode of a zinc air battery, platinum (Pt) and iridium (Ir /) in which platinum (Pt) and iridium (Ir) are respectively supported on carbon (C) The composition dispersed in Nafion resin, wherein C) is a binder, may be coated on the surface of the metal mesh using an airbrush.

The present invention can form a coating layer containing the active material on the metal mesh surface more uniformly by forming a coating layer containing the active material on the metal mesh surface in the same manner.

Zinc-air secondary battery

Furthermore, in one embodiment of the present invention,

An air electrode including the transparent electrode;

A zinc electrode comprising a metal mesh containing zinc (Zn); And

A zinc-air secondary battery comprising an electrolyte gel containing hydroxide ions is provided.

The zinc-air secondary battery according to the present invention has a structure including the transparent electrode according to the present invention described above as an air electrode, comprises a metal mesh containing zinc (Zn) as a zinc electrode, and contains a gel containing hydroxide ions. It has a structure to include as an electrolyte.

1 is a schematic view showing a structure of a zinc-air secondary battery according to the present invention. As shown in FIG. 1, the zinc-air secondary battery has an electrolyte gel containing hydroxide ions disposed under a transparent electrode which is an air electrode. The surface on which the thin film is formed in the transparent electrode is in contact with the electrolyte gel, and the electrolyte gel may have a structure in which a zinc electrode including a metal mesh containing zinc (Zn) is impregnated.

In this case, the metal mesh included in the transparent electrode and the metal mesh included in the zinc electrode may have different components of the metal wire constituting each metal mesh, but the average thickness of the metal wire, the shape or position of the metal wire, and the porosity may be the same. The metal mesh included in both electrodes may be positioned to coincide. In this case, alignment of the lattice structures of the metal meshes included in the two electrodes may be matched to prevent the formation of a moire's pattern that inhibits optical transparency.

Meanwhile, the metal mesh included in the zinc electrode may contain zinc (Zn) as an active material, and may include a zinc mesh made of zinc wire or an electrode deposited with zinc (Zn) on a stainless steel mesh. have.

The present invention can use a zinc mesh or a zinc (Zn) electrodeposited stainless steel mesh as the metal mesh of the zinc electrode to realize a high energy density without a significant increase in the volume of the metal mesh due to the active material coating, the light transmittance of the zinc electrode Can be optimized and the polarization can be reduced by mitigating the free diffusion effect on the zinc ion species generated during charging and discharging.

The zinc-air secondary battery according to the present invention has the above configuration, the average light transmittance of the battery may be 30% or more with respect to light having a wavelength of 400 nm to 700 nm, more specifically 35% or more, 40% or more , 45% or more, 30% to 90%, 30% to 80%, 30% to 70%, 30% to 60%, 40% to 80% or 50% to 90%.

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples.

However, the following Examples and Experimental Examples are only illustrative of the present invention, and the content of the present invention is not limited to the following Examples and Experimental Examples.

Example  1 to 4. Preparation of Transparent Electrode

Pt / C catalyst (0.07 g) and Ir loading of 20 wt% Pt loading in a solution of Nafion (1 mL) dissolved in isopropyl alcohol (20 mL) (Nafion concentration: 5 wt%) A catalyst slurry was prepared by adding Ir / C catalyst (0.07 g) by weight.

A stainless steel mesh (100 mesh, metal wire average diameter: 30.5 ± 0.1 μm, pore average size: 223.5 ± 0.1 μm, porosity: 79 ± 1%) was commercially purchased and cut into 4 cm width and 4 cm length. The previously prepared catalyst slurry was then coated onto the cut stainless steel mesh using an air brush and dried in a 50 ° C. oven. In this case, the total content of the catalyst coated on the stainless steel mesh after drying is shown in Table 1 below, and the appearance of the catalyst content of the catalyst-coated metal wire (ie, stainless steel wire) by optical microscope (Motic, BA310MET) Taken as shown in FIG. 3:

Total content per unit area of coated catalyst Example 1 0.0125 mg / cm 2 Example 2 0.25 mg / ㎠ Example 3 0.5 mg / cm 2 Example 4 1.0 mg / cm 2

Separately, on a polyethylene terephthalate substrate, a solution in which an anion exchange resin having a structure in which a quaternary ammonium group is introduced into an aromatic ring is dissolved at a concentration of 10% by weight is applied with an 80% doctor blade, and a 90 ° C. oven is used. The previously applied anion exchange resin was left to dry for half a minute (drying rate: about 70 ± 1 %%) and then the previously prepared stainless steel mesh was laminated on the semi-dried anion exchange resin. At this time, the stainless steel mesh was immersed in the semi-dried anion exchange resin without external force. After drying overnight at room temperature, the dried anion exchange resin was immersed in 0.1M KOH aqueous solution for 24 hours, and then the cured product was taken out to remove the stainless steel mesh from the anion exchange resin and anion exchange along the metal wire of the mesh on one side of the stainless steel mesh. Resin was bottled to prepare a transparent electrode including the thin film of the dried form. The surface and cross section of the prepared transparent electrode were photographed with an optical microscope (Motic, BA310MET) and a field emission-scanning electron microscope (FE-SEM, JSM-7800F, JEOL Ltd.) and are shown in FIG. 4.

Referring to Figure 4, the transparent electrode according to the present invention comprises a stainless steel mesh, an anion exchange resin is bottled and dried along the metal wire included in the mesh on one surface of the mesh, the thin film is a stainless steel mesh It can be confirmed that the structure has pores at the same position as the openings (ie, pores) of. In addition, since the anion exchange resin is yellow, including the quaternary ammonium group, it can be seen that the dried thin film of the anion exchange resin is also pale yellow.

In addition, the thin film is affected by the structure of the stainless steel mesh to be fed can be seen that the thickness is not constant. Specifically, the stainless steel mesh has the structure of a fabric in which the stainless steel wire is woven so that the stainless steel wire in the horizontal position alternates up and down the stainless steel wire in the vertical position. As a result, the thin film bottled and dried on one side of the stainless steel mesh has a thickness of about 13 ± 0.5 μm when the stainless steel wire in the horizontal position runs over the stainless steel wire in the vertical position, and is below the stainless steel wire in the vertical position. When the progression has a thickness of about 3 ± 0.5㎛, it can be seen that the average thickness is about 8 ± 0.5㎛.

Production Example  1 to 3. Preparation of Zinc Electrode

A stainless steel mesh (100 mesh, metal wire average diameter: 30.5 ± 0.1 μm, pore average size: 223.5 ± 0.1 μm, porosity: 79 ± 1%) was commercially purchased and cut into 4 cm width and 4 cm length.

Separately, zinc acetate dihydrate (25 g) was added to a 10% by weight aqueous solution of acetic acid (200 ml) to completely dissolve the plating solution, and the plating bath was prepared so that the previously cut stainless steel mesh and the zinc source, zinc plate, were parallel at 1 cm intervals. After fixing to the plating solution prepared was injected into the plating bath. Thereafter, a current was applied under conditions of 250 ± 2 mA / cm 2 to electrodeposit the surface of the stainless steel mesh with zinc. At this time, ultrasonic irradiation was performed together to remove hydrogen bubbles initially generated on the surface of the stainless steel mesh during the electroplating, and the ultrasonic irradiation was terminated when no hydrogen bubbles were generated. The electroplating was continued until the amount of zinc electrodeposited on the surface of the stainless steel mesh is as shown in Table 2 below, when the electroplating is finished, washed with distilled water and vacuum dried. The appearance of the metal wire included in the prepared zinc electrode was photographed with an optical microscope (Motic, BA310MET) and is shown in FIG. 3.

Content per unit area of electrodeposited zinc (Zn) Preparation Example 1 2 mg / cm 2 Preparation Example 2 5 mg / cm 2 Preparation Example 3 8 mg / cm 2

compare Production Example  1. Fabrication of Zinc Electrodes

A stainless steel mesh (100 mesh, metal wire average diameter: 30.5 ± 0.1 μm, pore average size: 223.5 ± 0.1 μm, porosity: 79 ± 1%) was commercially purchased and cut into 4 cm width and 4 cm length. Then, a composition containing zinc powder (5 g) and polyacrylic acid (5 g) was applied onto a stainless steel mesh to prepare a zinc electrode.

Example  5. Preparation of Zinc-Air Secondary Battery

The four edges of the zinc electrode obtained in Preparation Example 2 were fixed on a transparent polyethylene terephthalate substrate, and polyacrylic acid (PAA, viscosity average molecular weight (Mv) ≤ 450,000) mixed with 6 M KOH aqueous solution at 10% by weight was doctor blade. The electrolyte gel of the zinc electrode-impregnated structure was prepared by casting. Thereafter, the transparent electrode obtained in Example 3 was positioned so as to overlap the mesh structure of the impregnated zinc electrode, a gasket of 2 cm wide and 2 cm long was placed, and then a copper tape was attached to both electrodes as current leads. An air secondary battery was prepared.

Example  6. Preparation of Zinc-Air Secondary Battery

In Example 5, instead of using the transparent electrode of Example 3, using a zinc mesh (100 mesh, metal wire average diameter: 30.5 ± 0.1 μm, pore average size: 223.5 ± 0.1 μm, porosity: 79 ± 1%) A zinc-air secondary battery was prepared in the same manner as in Example 5 except that the zinc-air secondary battery was prepared.

Comparative example  1. Preparation of Transparent Electrode

Pt / C catalyst (0.07 g) and Ir loading of 20 wt% Pt loading in a solution of Nafion (1 mL) dissolved in isopropyl alcohol (20 mL) (Nafion concentration: 5 wt%) A catalyst slurry was prepared by adding Ir / C catalyst (0.07 g) by weight.

A stainless steel mesh (100 mesh, metal wire average diameter: 30.5 ± 0.1 μm, pore average size: 223.5 ± 0.1 μm, porosity: 79 ± 1%) was commercially purchased and cut into 4 cm width and 4 cm length. The previously prepared catalyst slurry was then coated onto the cut stainless steel mesh using an air brush and dried in a 50 ° C. oven. At this time, the total content per unit area of the catalyst coated on the stainless steel mesh after drying was 0.5 mg / cm 2.

Separately, on a polyethylene terephthalate substrate, a solution in which an anion exchange resin having a structure in which a quaternary ammonium group is introduced into an aromatic ring is dissolved at a concentration of 10% by weight is applied with an 80% doctor blade and placed in a 50 ° C oven. After leaving the applied anion exchange resin to dry for a period of time completely, a previously prepared stainless steel mesh was laminated on the prepared anion exchange resin to prepare a transparent electrode. The prepared transparent electrode has a structure in which an anion exchange resin, which is a thin film, is simply laminated in a sheet form on one surface of a stainless steel mesh.

Comparative example  2. Preparation of Zinc-Air Secondary Battery

In Example 5, a zinc-air secondary battery was prepared in the same manner as in Example 5 except that the transparent electrode of Comparative Example 1 was used instead of the transparent electrode of Example 3.

Experimental Example  1. Optical property evaluation

In order to evaluate the optical properties of the transparent electrode and the zinc-air secondary battery including the same according to the present invention, specifically, the light transmittance, obtained in Example 3 and Comparative Example 1 using a UV-Vis spectrometer (Mecasys, Optizen2120UV) The visible light transmission spectrum of the transparent electrode and the zinc-air secondary battery obtained in Example 5 was measured. In this case, the wavelength range of the measured light was 400 nm to 700 nm, and the measured results are shown in FIGS. 5 and 6.

Referring to FIGS. 5 and 6, FIG. 5 is a graph showing light transmittances of the transparent electrodes of Example 3 and Comparative Example 1, wherein an anion exchange resin includes a thin film that is bottled and dried along a metal line of a stainless steel mesh. The transparent electrode of 3 was found to have an average of 45% or more, specifically about 47.5 ± 0.5%.

On the other hand, the transparent electrode of Comparative Example 1 having a thin film of stainless steel mesh and an anion exchange resin dried in the form of a sheet exhibited a light transmittance of less than 45% over the entire wavelength range of 400 nm to 700 nm, in particular from 400 nm to 500 nm. In the low wavelength region, the light transmittance was lower than about 40%.

When the yellow anion exchange resin like the transparent electrode of the present invention is bottled and dried along the metal wire of the metal mesh, the light transmittance is constant because the pores of the thin film are formed in the opening of the metal mesh to provide a path through which light is transmitted. When the thin film containing the anion exchange resin is introduced to one surface of the metal mesh in the form of a sheet, the opening of the metal mesh is closed by the thin film so that the violet color, which is the complementary color of the thin film color, and the transmittance of the blue color close thereto are In particular, it means reduced.

6I is a graph showing a light transmittance graph in the wavelength range of 400 nm to 700 nm for the zinc-air secondary battery of Example 3 and each component constituting the same, wherein the untreated stainless steel mesh has an average light The transmittance was about 74.1%, the average light transmittance of the air electrode and the zinc electrode was about 64.9% and 71.1%, and the average light transmittance of the zinc-air secondary battery assembled therewith was found to be about 48.8%. In this case, the transparent electrode (average thickness: about 50㎛) has a low light transmittance because the average thickness is thick compared to the zinc electrode (average thickness: about 55㎛).

In addition, II of FIG. 6 shows the actual light transmittance and the theoretical light transmittance according to the active material content of the transparent electrode and the zinc electrode, wherein the average thickness of the metal mesh included in the electrode is calculated from the optical microscope image of FIG. And the theoretical light transmittance of each electrode was calculated | required using following formula (1).

[Equation 1]

Looking at II of Figure 6, the transparent electrode and the zinc electrode showed a tendency that the light transmittance decreases as the content of the active material loaded on the metal mesh is increased. In addition, the actual light transmittances of the two electrodes showed theoretical approximations and marginal deviations assumed in two dimensions.

Furthermore, referring to III of FIG. 6 photographing a zinc-air secondary battery according to the present invention, it can be seen that the secondary battery maintains a transparent state regardless of bending.

From these results, it can be seen that the transparent electrode and the zinc-air secondary battery including the same according to the present invention have excellent light transmittance.

Experimental Example  2. Electrical property evaluation

In order to evaluate the electrical properties of the transparent electrode and the zinc-air secondary battery including the same according to the present invention, the following experiment was performed.

end. Ohm resistance of the electrode

Zinc electrode obtained in Preparation Example 2 and Comparative Preparation Example 1; And the ohmic resistance of the electrode using the electrochemical impedance spectroscopy (EIS) was measured for the transparent electrode obtained in Example 3 and Comparative Example 1. Specifically, a commercially available cobalt oxide-containing electrode was commercially purchased as an air electrode, and a 6M KOH aqueous solution was prepared as an electrolyte. Thereafter, the transparent electrodes obtained in Example 3 and Comparative Example 1 were respectively set up to prepare cells, and the ohmic resistance of the prepared cells was measured and shown in FIGS. 7 and 8.

7 is a zinc electrode coated with a polymer composition in which zinc (Zn) is electrodeposited on a metal mesh (Preparation Example 2) and (b) a zinc (Zn) powder is dispersed on a metal mesh (comparative manufacture) As a graph showing ohmic resistance of Example 1), the ohmic resistance of the zinc electrode of Preparation Example 2 in which zinc (Zn) was electrodeposited on the metal mesh was 8.71Ω, and was coated with the polymer composition of Comparative Preparation Example 1 It can be seen that the ohmic resistance of the zinc electrode is 11.92 Ω. This indicates that the electrode electrodeposited with zinc on the metal mesh is densely packed with the active material zinc (Zn) to realize high energy density without significant volume increase.

8 illustrates a structure in which (a) a transparent electrode (Example 2) having a structure in which a thin film containing an anion exchange resin is bottled on one surface of a metal mesh and (b) a sheet-like thin film is stacked on one surface of a metal mesh. As a graph showing ohmic resistance of the transparent electrode (Comparative Example 1), it can be seen that the internal resistance of the transparent electrode of Example 2 is significantly reduced compared to the transparent electrode of Comparative Example 1.

I. Measurement of physical properties according to bending angle of zinc-air secondary battery

The number of charge / discharge cycles, the current density, and the ohmic resistance of the zinc-air secondary battery prepared in Example 3 according to the bending angle of the battery were measured. Specifically, the number of charge / discharge cycles of the battery is based on a cycle system (WBCS3000, WonATech) for 5 minutes at a constant current of 1 mA at a charge cut-off voltage of 0.8V and a charge voltage of 2.7V. Time: 10 minutes) to determine the order in which the charge-discharge voltage changes. In addition, the current density and ohmic resistance of the battery were measured using electrochemical impedance spectroscopy (EIS), and the results are shown in Table 3 and FIG. 9.

Bending angle of battery Initial Open Circuit Voltage (OCV) Cut-off voltage Number of charge / discharge cycles 0 ° 1.43 V 0.8V / 2.7V 101 times 90 ° 1.43 V 0.8V / 2.7V 120 times 180 ° 1.47 V 0.8V / 2.7V 123 times

9A is a camera photographing image showing the bending angle of the battery, B is a graph showing the voltage according to the number of charging and discharging according to the bending angle, C is a graph showing the current density of the battery, and D is the bending of the battery. It is a graph showing ohmic resistance by angle.

Referring to Table 3 and FIG. 9, the zinc-air secondary battery of Example 3 has an initial open circuit voltage (OCV) of 1.42 to 1.50 V, specifically, at bending angles of 0 °, 90 °, and 180 °, respectively. 1.43V, 1.43V and 1.47V, and the maximum number of charge / discharge cycles was found to exceed 100 times regardless of the bending angle.

From these results, the zinc-air secondary battery of the present invention is provided with a transparent electrode according to the present invention means not only excellent light transmittance but also excellent electrical properties and flexibility.

Claims (16)

Metal mesh; And
A thin film located on one surface of the metal mesh and including an ion exchange resin,
The thin film is a transparent electrode having a structure is formed along the metal wire included in the metal mesh comprises pores.
The method of claim 1,
The metal mesh is a stainless steel mesh, gold mesh, silver mesh or copper mesh transparent electrode.
The method of claim 1,
The transparent electrode of which the average diameter of a metal wire is 1 micrometer-100 micrometers.
The method of claim 1,
The ion exchange resin is a transparent electrode which is an anion exchange resin comprising at least one functional group selected from the group consisting of quaternary ammonium groups, iminoacetic acid groups and thiourea groups.
The method of claim 1,
The transparent electrode having an average thickness of 1 μm to 15 μm.
The method of claim 1,
The metal mesh is a transparent electrode coated with a layer containing a catalyst comprising at least one metal selected from the group consisting of platinum (Pt), iridium (Ir), cobalt (Co) and manganese (Mn) or an oxide thereof.
Laminating a metal mesh on the partially dried ion exchange resin;
Immersing the ion exchange resin in which the metal mesh is laminated in a hydroxide solution; And
Desorbing the metal mesh from the immersed ion exchange resin, to obtain a transparent electrode having a thin film formed with an ion exchange resin along the metal wire on one surface of the metal mesh.
The method of claim 7, wherein
Hydroxide solution is a method for producing a transparent electrode comprising at least one selected from the group consisting of NaOH, KOH, Mg (OH) ₂ , Ca (OH) ₂ and Ba (OH) ₂ .
The method of claim 7, wherein
The concentration of the hydroxide solution is a method for producing a transparent electrode of 0.01 M to 5M.
The method of claim 7, wherein
Immersion time is a method for producing a transparent electrode of 10 hours to 50 hours.
The method of claim 7, wherein
Prior to laminating the metal mesh on the ion exchange resin,
Coating a metal mesh surface with a composition comprising a catalyst and a binder comprising at least one metal or oxide thereof selected from the group consisting of platinum (Pt), iridium (Ir), cobalt (Co) and manganese (Mn) Method for producing a transparent electrode comprising a.
The method of claim 11,
Coating the metal mesh surface includes air brush, Mayer, D-bar, rubber roll, G / V roll, air knife Method of manufacturing a transparent electrode carried out by knife or slot die.
An air electrode comprising a transparent electrode according to claim 1;
A zinc electrode comprising a metal mesh containing zinc (Zn); And
A zinc-air secondary battery comprising an electrolyte gel containing hydroxide ions.
The method of claim 13,
Zinc-air secondary battery, characterized in that the metal mesh contained in the zinc electrode is a zinc mesh or a stainless steel mesh electrode (Zn) electrodeposited (Zn).
The method of claim 13,
A zinc electrode is a zinc-air secondary battery having a structure in which a metal mesh containing zinc (Zn) is impregnated into an electrolyte gel.
The method of claim 13,
The average light transmittance of the zinc-air secondary battery is 30% or more for light having a wavelength of 400 nm to 700 nm, zinc-air secondary battery.

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