KR101814525B1 - Method of manufacturing Graphene electrode material - Google Patents

Abstract

The present invention provides a method for producing a graphene electrode material doped with a metal oxide and nitrogen, having high electrical conductivity, high activity, and high stability. A method of fabricating a graphene electrode material according to an embodiment of the present invention includes: forming a graphene doped with a metal and nitrogen; Mixing the metal and nitrogen-doped graphene with a polymer to form a spinning solution; Spinning the spinning solution using an electrospinning method to form a mesh structure; And heat treating the mesh structure to form a graphene electrode material doped with a metal oxide and nitrogen.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of manufacturing a graphene electrode material,

The technical idea of the present invention relates to a graphene electrode material. More particularly, the present invention relates to a graphene electrode material, a method of manufacturing the same, a metal air cell including the same, a solid oxide fuel cell including the same, and a solid oxide water-receiving cell comprising the same.

In recent years, solid oxide fuel cells and metal air cells have been actively studied as secondary replacements that can replace conventional lithium ion batteries.

A solid oxide fuel cell (SOFC) is a highly efficient, environmentally friendly electrochemical power generation technology that directly converts the chemical energy of a fuel gas into electrical energy. Since all components are solid, SOFC has a simple structure, relatively low cost, and is free from electrolyte loss and replacement and corrosion problems compared to other fuel cells. The metal air cell is a secondary battery technology which is much higher in energy density than the lithium ion battery having the highest energy density among currently used secondary batteries and is actively studied as a next generation energy source for electric vehicles and the like.

The solid oxide fuel cell and the metal air cell are required to have a noble metal catalyst such as platinum due to the slow oxygen reduction reaction, so that the manufacturing cost is high. In addition, Li ₂ CO ₃ compounds formed by side reactions of the cathode may deteriorate battery performance and shorten battery life. Therefore, it is required that the current collector composed of a carbon body or the like does not react with lithium ions or the like.

Further, the anode used as the catalyst has a problem that the anode electrode is rapidly destroyed by carbon deposition. Also, it is very important that the anode electrode should have a stable structure in a hydrogen environment, and at the same time maintain an electric conductivity higher than a certain value. There is a possibility that the performance of the anode may deteriorate during long-term use in such a hydrogen environment.

Therefore, development of an electrode material having high electrical conductivity at room temperature, high activity such as oxygen reduction reaction and oxygen generation reaction, and high stability is required.

1. Korean Patent No. 10-1216052 2. Korean Patent No. 10-1245815

Disclosure of Invention Technical Problem [8] The present invention provides a graphene electrode material doped with a metal oxide and nitrogen, having high electrical conductivity, high activity, and high stability.

SUMMARY OF THE INVENTION The present invention provides a method of manufacturing a graphene electrode material having high electrical conductivity, high activity, and high stability.

Another object of the present invention is to provide a metal air cell including the graphene electrode material.

Another object of the present invention is to provide a solid oxide fuel cell including the graphene electrode material.

Another object of the present invention is to provide a solid oxide electrolytic cell including a graphene electrode material.

According to an aspect of the present invention, there is provided a method of manufacturing a graphene electrode material, the method including forming graphene doped with a metal and nitrogen; Mixing the metal and nitrogen-doped graphene with a polymer to form a spinning solution; Spinning the spinning solution using an electrospinning method to form a mesh structure; And heat treating the mesh structure to form a graphene electrode material doped with a metal oxide and nitrogen.

In one embodiment of the present invention, the step of forming the metal and nitrogen-doped graphene comprises the steps of charging graphite and a metal ball into a metal container; Forming an interior of the metal container in a nitrogen atmosphere; And grinding the graphite by ball milling using the metal balls to form graphene doped with a metal and nitrogen.

 In one embodiment of the present invention, the graphite may include a powder having a size of 10 mesh to 1000 mesh.

In one embodiment of the present invention, the metal ball and the metal container may be made of stainless steel, Fe, Cr, Ni, Sc, Ti, V, (Mn), Co, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, (Rh), Pd, Ag, Cd, Hafnium, Ta, W, Re, Platinum (Pt), gold (Au), or an alloy thereof.

In one embodiment of the present invention, a metal doped to the graphene may be provided from the metal ball, the metal container, or both.

According to an embodiment of the present invention, the step of forming the metal container in the nitrogen atmosphere includes repeatedly performing the step of filling and discharging the metal container with the nitrogen gas, and finally filling the metal container with the nitrogen gas .

In one embodiment of the present invention, the metal doped in the graphene is disposed to interpose between the carbon atoms constituting the graphene, or the metal atom bonded to the carbon atom is substituted with the carbon atom Or may be substituted by substituting the carbon atoms.

In one embodiment of the present invention, the step of heat treating the mesh structure to form a graphene electrode material doped with a metal oxide and nitrogen may include forming the mesh structure of the mesh structure so that the polymer of the mesh structure forms a ring structure. Stabilization processing; Carbonizing the mesh structure having the annular structure formed thereon; And activating the carbonization-treated mesh structure.

In one embodiment of the present invention, the step of stabilizing may be performed at a temperature ranging from 250 ° C to 350 ° C in an air atmosphere.

In one embodiment of the present invention, the step of carbonizing may be performed at a temperature in the range of 900 ° C to 1100 ° C in an inert atmosphere.

In one embodiment of the present invention, the activating step may be performed at a temperature in the range of 700 ° C to 900 ° C in a carbon dioxide atmosphere.

In one embodiment of the present invention, the step of stabilizing is performed in an air atmosphere at a temperature of 280 DEG C for 1 hour, and the carbonization step is performed in a nitrogen gas atmosphere at a temperature of 1000 DEG C for 1 hour , The activation step may be carried out at a temperature of 800 DEG C for 1 hour in a carbon dioxide atmosphere.

In one embodiment of the present invention, the metal doped in the graphene may form a metal oxide in the step of stabilizing, in the step of carbonizing, or in both steps.

In one embodiment of the present invention, the polymer is selected from the group consisting of polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), polyurethane, (PMA), polyvinyl acetate (PVAc), polyacrylonitrile (PAN), polypyryl alcohol (PPFA), polystyrene, polyethylene (PE), polyvinyl pyrrolidone (PEO), polypropylene oxide (PPO), polycarbonate (PC), polyvinyl chloride (PVC), polycaprolactone, polyvinyl fluoride, and polyamide .

According to an aspect of the present invention, a graphene electrode material is formed using the above-described method, and is doped with a metal oxide and nitrogen.

According to an aspect of the present invention, there is provided a graphene electrode material comprising: a network structure composed of carbon; And graphene coupled to the mesh structure and doped with a metal oxide and nitrogen.

In one embodiment of the present invention, the graphene may be exposed to the surface of the mesh structure.

According to an aspect of the present invention, there is provided a metal air cell including a cathode including a metal oxide and a nitrogen-doped graphene electrode material; An anode facing the cathode; And an electrolyte disposed between the cathode and the cathode.

According to an aspect of the present invention, there is provided a solid oxide fuel cell comprising: a cathode comprising a graphene electrode material doped with a metal oxide and nitrogen; An anode facing the cathode; And an electrolyte disposed between the cathode and the cathode.

According to an aspect of the present invention, there is provided a solid oxide water receiving cell including a cathode for discharging hydrogen gas formed by decomposition of water; An anode disposed facing the cathode and discharging the oxygen gas formed by decomposition of the water; And an electrolyte disposed between the anode and the cathode, wherein the cathode comprises a graphene electrode material doped with a metal oxide and nitrogen.

According to an embodiment of the present invention, there is provided a graphene electrode material doped with a metal oxide and nitrogen.

The graphene electrode material doped with the metal oxide and nitrogen means that as the metal oxide is doped into the graphene, the oxygen reduction reaction starts at a lower voltage than the comparative examples, and furthermore, at the same voltage, . The embodiment showed a disc current (i _disk ) value in the range of about -6 to -7 as the absolute value of the voltage increased. The oxygen reduction reaction characteristic of this embodiment means that the embodiment of the present invention provides a quick oxygen reduction reaction and can generate a large amount of current. A good catalyst for an oxygen reduction reaction must have an oxygen reduction reaction that starts at a lower voltage and generates a lot of current under the same voltage. Therefore, the metal oxide and nitrogen-doped graphene electrode materials of the present invention can be excellent catalysts for the oxygen reduction reaction.

Since the graphene electrode material doped with the metal oxide and nitrogen can provide long-term stability and exhibits excellent performance of oxygen reduction reaction, it is possible to increase the activity of the battery, increase the stability, It can reduce the price.

The graphene electrode material doped with the metal oxide and nitrogen may be used as an electrode material of a metal air cell, a solid oxide fuel cell, and a solid oxide water-dissolving cell.

1 is a flow chart showing a method of manufacturing a graphene electrode material according to an embodiment of the present invention.
Figure 2 is a flow chart illustrating the step of forming the metal and nitrogen doped graphene of Figure 1 according to one embodiment of the present invention.
FIG. 3 is a schematic view illustrating the step of grinding the graphite of FIG. 2 by ball milling using the metal ball to form a metal and nitrogen-doped graphene according to a temporal example of the present invention.
Fig. 4 is a schematic diagram showing a metal and nitrogen-doped graphene formed in the step of forming the metal and nitrogen-doped graphene of Fig. 2 according to a temporal example of the present invention; Fig.
Fig. 5 is a schematic view showing an electrospinning apparatus for performing the electrospinning method of the method of manufacturing the graphene electrode material of Fig. 1 according to an embodiment of the present invention.
FIG. 6 is a schematic view showing a state in which a spinning solution is radiated in the electrospinning apparatus of FIG. 5 according to an embodiment of the present invention. FIG.
FIG. 7 is a flow chart illustrating a step of heat treating the mesh structure of FIG. 1 to form a metal oxide and nitrogen-doped graphene electrode material, according to an embodiment of the present invention.
8 is a schematic view illustrating a metal air cell including an electrode formed of a metal oxide and a nitrogen-doped graphene electrode material, according to an embodiment of the present invention.
9 is a schematic diagram illustrating a solid oxide fuel cell including an electrode formed of a metal oxide and a nitrogen-doped graphene electrode material, according to an embodiment of the present invention.
10 is a schematic diagram illustrating a solid oxide acceptance cell including an electrode formed of a metal oxide and a nitrogen-doped graphene electrode material, according to an embodiment of the present invention.
11 and 12 are SEM micrographs showing a metal oxide and nitrogen-doped graphene electrode material prepared according to a temporary example of the present invention.
FIG. 13 is a transmission electron microscope photograph showing a metal oxide and nitrogen-doped graphene electrode material manufactured according to a temporary example of the present invention.
FIG. 14 is a graph illustrating an oxygen reduction reaction of a metal oxide and a nitrogen-doped graphene electrode material manufactured according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail. In interpreting the terms or words used in the present specification and claims, it is to be understood that the interpretation of terms or words used herein is necessarily conventional, based on the principle that the inventor can properly define the concept of the term to describe its invention in the best way It is to be understood that the invention is not to be interpreted as being limited only by the precautionary sense, but should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention as described in the present specification.

The technical idea of the present invention is to provide an electrode material comprising graphene. Graphene is a two-dimensional carbon nanostructure, has a charge mobility of about 15,000 cm ² / Vs, and is known to have excellent thermal conductivity. As a result, graphene has attracted attention as a next-generation material to replace silicon materials currently used for field-effect transistors, and is expected to be used as an electrode material. In the case of using a graphen material, it is easy to manufacture a device by using a conventional semiconductor process technology or a photoelectric device process technology, and particularly, it is advantageous in that it can be easily integrated in a large area. Since graphene has high rigidity and electrical conductivity, it is expected to be applied to a transparent electrode of a photoelectric device, a solar cell, or an active layer of an electronic device.

1 is a flow chart showing a method (S100) for manufacturing a graphene electrode material according to an embodiment of the present invention.

Referring to FIG. 1, a method (S100) for manufacturing a graphene electrode material includes forming a graphene doped with a metal and nitrogen (S110); Mixing the metal and nitrogen-doped graphene with a polymer to form a spinning solution (S120); (S130) spinning the spinning solution using an electrospinning method to form a mesh structure; And a step (S140) of heat treating the mesh structure to form a graphene electrode material doped with a metal oxide and nitrogen.

Figure 2 is a flow diagram illustrating step S110 of forming the metal and nitrogen doped graphene of Figure 1 according to an embodiment of the present invention.

Referring to FIG. 2, step (S110) of forming the metal and nitrogen-doped graphene comprises: charging (S111) a graphite and a metal ball into a metal container; Forming an interior of the metal container in a nitrogen atmosphere (S112); And grinding the graphite by ball milling using the metal balls to form graphene doped with a metal and nitrogen (S113).

In step S111 of loading the graphite and the metal balls into the metal container, the graphite may have a bulk form or may have a powder form. The graphite may include, for example, powder having a size of 10 mesh to 1000 mesh, and may include powder having a size of 100 mesh, for example. The metal ball may have a size of, for example, 1 mm to 10 mm in diameter, and may have a size of, for example, 5 mm in diameter.

The metal ball and the metal container may include a metal, and may include, for example, a transition metal. The metal ball and the metal container may be made of the same material or may be made of different materials. For example, the metal ball and the metal container may be made of stainless steel. However, this is illustrative and the technical idea of the present invention is not limited thereto. For example, the metal balls and the metal container may be formed of a metal such as iron (Fe), chromium (Cr), nickel (Ni), scandium (Sc), titanium (Ti), vanadium (V), manganese ), Copper (Cu), zinc (Zn), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), rubidium (Ru) ), Silver (Ag), cadmium (Cd), hafnium (Hf), thallium (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium ), Or an alloy thereof.

In the step (S112) of forming the interior of the metal container in a nitrogen atmosphere, the nitrogen atmosphere may be formed using nitrogen gas (N ₂ ). The step S112 of forming the interior of the metal container in a nitrogen atmosphere may include repeating the step of filling the metal container with nitrogen gas and discharging the metal container repeatedly and finally filling the metal container with nitrogen gas . Due to such repetitive filling and discharging, the inside of the metal container can be filled with nitrogen gas of high purity. The step of forming the inside of the metal container in a nitrogen atmosphere (S112) may be performed at a pressure of, for example, 1 bar to 20 bar, for example, 8 bar.

The step (S113) of forming the graphite and the nitrogen-doped graphene by pulverizing the graphite using the metal ball by ball milling can be carried out by mixing the graphite and the metal ball at a speed of, for example, 100 rpm to 1000 rpm, And rotated at a speed of 500 rpm. This rotation time can be performed, for example, from 1 hour to 100 hours, and can be performed, for example, for 48 hours.

During the step S113, the graphite is pulverized to form graphene, and nitrogen decomposed from the nitrogen gas and a metal provided from the metal ball, the metal container, or both can be doped to the graphene. Thus, metal and nitrogen-doped graphene can be formed. For example, when the metal ball and the metal container are made of stainless steel, the graphene may be doped with a material such as iron (Fe), chromium (Cr), nickel (Ni) have.

FIG. 3 is a schematic view for explaining a step (S113) of grinding the graphite of FIG. 2 by ball milling using the metal ball to form a graphene doped with a metal and nitrogen according to a temporal example of the present invention.

Referring to Fig. 3, the graphite shown on the left side has a laminated structure in which a plurality of carbon plate layers are laminated, and is crushed by the metal balls during the ball milling step in the metal vessel. The ground graphite can be decomposed into graphene shown on the right side. The graphene may be composed of one layer of carbon structure, and nitrogen may be coupled to the outside of the carbon structure to be doped. In FIG. 3 doping of the metal atoms is omitted, and such graphenes are shown in more detail in FIG. 4 below.

FIG. 4 is a schematic diagram showing a metal and nitrogen-doped graphene 100 formed in step S113 of forming the metal and nitrogen-doped graphene of FIG. 2 according to a temporal example of the present invention.

Referring to FIG. 4, the graphene 1 doped with a metal and nitrogen has carbon atoms 2 constituting the carbon structure, nitrogen atoms 3 bonded to a part of the carbon atoms 2, and metal atoms 4 ). Metal atoms 4 may be provided from the metal balls or metal containers as described above. For example, the metal balls may be partially or partly broken or peeled during the grinding of the graphite to discharge metal atoms, and such metal atoms may be doped into the graphene structure. The metal atom (4) is a metal atom (4) which is substituted with a carbon atom (2) by substituting a first metal atom (41) and a nitrogen atom (3) A second metal atom 42 disposed thereon, and a third metal atom 43 substituted with carbon atoms 2 in the graphene structure.

However, the method of forming the above-described metal oxide and nitrogen-doped graphene is exemplary and the technical idea of the present invention is not limited thereto.

Referring again to FIG. 1, forming the spinning solution (S120) may be performed by mixing the metal and nitrogen-doped graphene with a polymer. The polymer may be composed of a polymer solution in which the polymer material is dissolved or dispersed in a solvent. Alternatively, the polymer may be formed by dispersing graphene in a solvent, and then dissolving a solid polymer in the solvent.

The polymer material may be selected from the group consisting of polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), polyurethane, polyether urethane, cellulose acetate, Cellulose acetate butyrate, cellulose acetate propionate, polymethyl acrylate (PMA), polyvinyl acetate (PVAc), polyacrylonitrile (PAN), polyperfuryl alcohol (PPFA), polystyrene, polyethylene oxide (PEO) And at least one selected from the group consisting of polypropylene oxide (PPO), polycarbonate (PC), polyvinyl chloride (PVC), polycaprolactone, polyvinyl fluoride, and polyamide. The polymer material may also include a copolymer of the above-mentioned materials, and may be, for example, a polyurethane copolymer, a polyacrylic copolymer, a polyvinyl acetate copolymer, a polystyrene copolymer, a polyethylene oxide copolymer, a polypropylene oxide copolymer , And a polyvinylidene fluoride copolymer. [0035] The term " a " However, these polymer materials are illustrative, and the technical idea of the present invention is not limited thereto.

The solvent may comprise a variety of solvent materials. For example, the solvent may be water, such as distilled water or deionized water, methanol, ethanol, acetone, benzene, toluene, hexane hexane, acetonitrile, N, N'-dimethylformamide (DMF), dimethylsulfoxide (DMSO), N-methylpyrrolidone (NMP), methylene chloride (CH ₂ Cl ₂ ), chloroform , CH ₃ Cl), tetrahydrofuran (THF), polyvinyl pyrrolidone (PVP), and mixtures thereof. Further, the solvent may be selected from the group consisting of Alkanes, Aromatics, Ethers, Alkyl halides, Esters, Aldehydes, Ketones, And may include various materials such as amines, alcohols, amides, and carboxylic acids. However, such a solvent is illustrative, and the technical idea of the present invention is not limited thereto.

The step of forming the spinning solution (S120) may be carried out at a suitable temperature for a suitable mixing time, for example at ambient temperature, or at a temperature in the range of 0 ° C to 100 ° C, RTI ID = 0.0 > 24 hours. ≪ / RTI >

The step S130 of spinning the spinning solution using an electrospinning method to form a network structure may be performed using an electrospinning method. The electrospinning method may spin the spinning solution onto a target substrate such as a collector substrate or a separate substrate disposed on the collector substrate to form a mesh structure. The target substrate may be removed after performing the heat treatment step (S140) after forming the mesh structure, or may be removed after performing the heat treatment step (S140). The target substrate may have various shapes and materials and may have a shape such as, for example, a plate shape, a drum shape, parallel rods, a plurality of intersecting rods, or a grid shape, Or may comprise an insulating material such as a glass or polymer material.

Such an electrospinning method can be performed by an electrospinning apparatus, and such electrospinning apparatus and method will be described in detail with reference to FIG.

5 is a schematic diagram showing an electrospinning apparatus 1000 that performs the electrospinning method of the method of manufacturing the graphene electrode material of FIG. 1 according to an embodiment of the present invention.

5, the electrospinning apparatus 1000 includes a spinning solution tank 10, a spinning nozzle 20, a spinneret nozzle tip 30, an external power source 40, and a collector substrate 50.

The spinning solution tank 10 may store the spinning solution 60. The spinning solution 60 may vary depending on the material to be spinned. The spinning solution 60 may be formed by mixing the metal and nitrogen-doped graphene with the polymer as in the spinning solution formed in the above-described production method (S100). The spinning solution tank 10 may pressurize the spinning solution 60 using a built-in pump (not shown) to provide the spinning solution 60 to the spinning nozzle 20.

The spinning nozzle 20 may receive the spinning solution 60 from the spinning solution tank 10 and spin the spinning solution 60 through the spinning nozzle tip 30 located at one end.

The spinneret nozzle tip 30 can spin the spinning solution 60 by the voltage applied by the external power source 40 after the spinning solution 60 is pressurized by the pump to fill the nozzle tube therein.

The external power supply 40 may provide a voltage such that the spinning solution 60 is radiated to the spinning nozzle 20. The voltage may vary depending on the type of spinning solution 60, the amount of spinning, the type of collector substrate 50, the process environment, and the like, and may range, for example, from about 100 V to about 30000 V, Lt; / RTI > As described above, the voltage applied by the external power supply 40 can radiate the spinning solution 60 filled in the spinneret nozzle tip 30. [

The collector substrate 50 is located below the spinneret 20 and receives the spinning solution 60 to be emitted. The collector substrate 50 may be grounded and accordingly have a ground voltage, for example, a voltage of 0V. Alternatively, the collector substrate 50 may have a voltage opposite to that of the spinneret 20. The positional relationship between the collector substrate 50 and the spinneret 20 is exemplary and the technical idea of the present invention is not limited thereto. For example, the case where the collector substrate 50 is positioned above the spinneret 20 and the spinning solution 60 radiated from the spinneret 20 emits in the upward direction is also included in the technical idea of the present invention. For example, the case where the collector substrate 50 is positioned horizontally with respect to the spinneret 20 and the spinning solution 60 radiated from the spinneret 20 is radiated in the horizontal direction is also included in the technical idea of the present invention. The collector substrate 50 may be on a horizontal axis or the same spatial axis as the spinneret 20.

The radiation nozzle 20 and the spinneret nozzle tip 30 are charged to a positive voltage or a negative voltage by the external power source 40 so that the spinning solution 60 is also charged, A voltage difference with the substrate 50 is generated. The spinning solution 60 at the end of the spinneret nozzle tip 30 may have a conical shape such as a Taylor cone when a voltage is applied to the spinneret 20 and the spinneret tip 30 by the external power source 40 . At this time, an electric field of about 50000 V / m to about 150000 V / m may be formed between the spinneret tip 30 and the spinning solution 60. By the voltage difference, the spinning solution 60 can be radiated to the collector substrate 50 and accommodated. This radiation principle can be referred to as electro-hydro dynamic inkjet or electro-spinning.

By controlling the flow rate of the spinning solution 60 and the voltage difference between the spinneret tip 30 and the collector substrate 50 the diameter and length of the fibers received in the collector substrate 50 by spinning solution 60 Can be controlled. For example, the fiber may have a thickness in the range of about 50 nm to 1 占 퐉 and a length in the range of about several 占 퐉 to several hundred 占 퐉.

Fig. 6 is a schematic view showing a state in which a spinning solution is radiated in the electrospinning apparatus 1000 of Fig. 5 according to an embodiment of the present invention.

Referring to FIG. 6, the spinneret nozzle tip 30 may spin the spinning solution 60 in a linear form, for example in the form of a wire or rod. Such radiation can be referred to as a spinning mode. The spinning solution 60 may be radiated in different forms depending on its physical properties such as the viscosity of the solution, the weight ratio of the solute in the solution, the type of solute and solution, and the molecular weight of the solute and solvent. Also, it can be radiated in different forms depending on the magnitude of the applied voltage. For example, the spinneret nozzle tip 30 may spin the spinning solution 60 in the form of a spray. This radiation can be referred to as a spray mode.

As shown in Fig. 6, when the spinning solution 60 is radiated in a linear form, the above-described network structure can be formed. Such a network structure may be arranged to constitute a one-dimensional, two-dimensional or three-dimensional network structure. For example, the network structure may be composed of a one-dimensional network structure in which a plurality of linear structures are connected in parallel and connected in a linear shape. For example, the network structure may be a two-dimensional network structure in which a plurality of linear-shaped structures are overlapped and connected to each other at a predetermined angle and connected in a planar shape. For example, the network structure may be composed of a three-dimensional network structure in which a plurality of linear-shaped structures are overlapped and connected to each other so as to have a predetermined angle and connected in a three-dimensional shape. The network structure may include various shapes, for example, a mesh shape or a web shape.

Referring again to FIG. 1, a step (S140) of forming a graphene electrode material doped with a metal oxide and nitrogen by heat treating the mesh structure may include various heat treatment steps. The heat treatment steps described below may be performed by charging the mesh structure to a heat treatment furnace, or by irradiating infrared rays to the mesh structure.

FIG. 7 is a flow chart illustrating a step (S140) of forming a metal oxide and nitrogen-doped graphene electrode material by heat treating the mesh structure of FIG. 1 according to an embodiment of the present invention.

Referring to FIG. 7, the step (S140) of forming a graphene electrode material doped with a metal oxide and nitrogen by heat treating the mesh structure may include forming a mesh structure of the mesh structure A stabilization processing step S141; Carbonizing the mesh structure having the annular structure formed therein (S142); And activating the carbonization-treated mesh structure (S143). This heat treatment may be performed after separating the mesh structure from the colletor substrate of the spinneret described above. Alternatively, after performing such a heat treatment, the mesh structure may be separated from the collet substrate.

The stabilizing step (S141) may be performed in a temperature range in which the polymer constituting the network structure can form a ring structure. The stabilizing step (S141) may be performed at a temperature in the range of, for example, 250 DEG C to 350 DEG C. [ The stabilization step (S141) may be performed in a variety of atmospheres. For example, an oxidizing atmosphere containing an air atmosphere or an oxygen gas, a reducing atmosphere containing hydrogen gas or the like, or an argon gas or a nitrogen gas , ≪ / RTI > The stabilization processing step S141 may be performed for a time ranging from, for example, 1 minute to 24 hours. For example, the stabilizing step (S141) may be performed in an air atmosphere at a temperature of about 280 DEG C for about one hour. In the stabilization step S141, the rate of temperature rise to the temperature at which the stabilization process is performed may be, for example, in the range of 0.1 占 폚 / min to 1000 占 폚 / min, for example, 2 [deg.] C / min.

The formation of the cyclic structure in the stabilization step (S141) can be realized by combining elements such as carbon, hydrogen, oxygen, nitrogen and the like constituting the polymer to form a cyclic structure. For example, when the polymer is polyacrylonitrile (PAN), the material constituting the polyacrylonitrile may form a pyrimidine ring. Such a pyrimidine ring can control the carbonation reaction and can be referred to as a dechlorination process.

The carbonization step (S142) may be performed in a temperature range for carbonizing the mesh structure having the ring structure formed thereon. The carbonization step (S142) may be performed at a temperature in the range of, for example, 900 DEG C to 1100 DEG C. [ Further, the carbonization step (S142) may be performed in an inert atmosphere containing argon gas or nitrogen gas. The carbonization step (S142) may be performed for a time ranging from, for example, 1 minute to 24 hours. For example, the carbonization step (S142) may be performed in a nitrogen gas atmosphere at a temperature of about 1000 캜 for about 1 hour. In the carbonization treatment step (S142), the temperature raising rate up to the temperature for performing the carbonization treatment may be, for example, in the range of 0.1 占 폚 / min to 1000 占 폚 / min, for example, 2 [deg.] C / min.

By the carbonization step (S142), unnecessary organic matters in the mesh structure are all removed, and the carbon component of the polymer and the graphene are left. Such residues can maintain the shape of the mesh structure formed before the stabilization treatment and the carbonization treatment. For example, a mesh structure composed of the carbon component of the polymer and graphene positioned inside the mesh structure may be formed.

The metal doped in the graphene may react with oxygen to form a metal oxide. These metal oxides may be present doped to the graphene. For example, the metal doped in the graphene may form a metal oxide in the stabilization step (S141), in the carbonization step (S142), or in both steps. In particular, at least a portion of the metal doped in the graphene may react with oxygen in the air to form a metal oxide in the stabilizing step (S 141). In addition, at least a part of the metal doped to the graphene may react with oxygen emitted from the polymer to form a metal oxide in the carbonization step (S142). The step of forming such a metal oxide is illustrative and the technical idea of the present invention is not limited thereto. For example, in the case where the metal oxide is formed in the step (S113) of grinding the graphite by ball milling using the metal ball to form graphene, and the graphene includes a metal oxide, Included in thought.

The step of activating (S143) may be performed in a temperature range that activates the catalytic properties of the metal or metal oxide doped in the graphene. The step S143 of performing the activation treatment may be performed at a temperature in the range of, for example, 700 ° C to 900 ° C. In addition, the activation step (S143) may be performed in a carbon dioxide gas atmosphere of 90% to 100%. The activation processing step S143 may be performed for a time ranging from, for example, 1 minute to 24 hours. For example, the activation step S143 may be performed at a temperature of about 800 DEG C for about 1 hour, for example, in a 100% carbon dioxide gas atmosphere. In the activation step S143, the temperature raising rate up to the temperature for performing the activation treatment may be, for example, in the range of 0.1 占 폚 / min to 1000 占 폚 / min, for example, 1 占 폚 / Lt; 0 > C / min.

In the activation step S143, the graphene may be exposed at the surface of the mesh structure. Such exposure can improve the catalytic properties of the graphene. In addition, at least a part of the metal doped in the graphene may react with oxygen in carbon dioxide to form a metal oxide in the activation treatment step (S143). The carbon dioxide can be converted into carbon monoxide by such a reaction.

By performing the heat treatment step S140 as described above, the metal doped in graphene can be converted into a metal oxide. Specifically, the metal atoms 4 shown in Fig. 4 can be changed to metal oxides. That is, the metal oxide may be interposed between the carbon atoms, such as the position of the first metal atom 41 in FIG. 4, or may be a nitrogen atom, such as the position of the second metal atom 42 in FIG. 4, May be arranged to substitute carbon atoms for substitution with an atom or substitute carbon atoms in the graphene structure such as the position of the third metal atom 43 in Fig.

The graphene electrode material doped with the metal oxide and nitrogen formed by the manufacturing method (S100) of the graphene electrode material of FIG. 1 can be applied to a cathode or an anode of a metal air cell, a solid oxide fuel cell, As shown in Fig.

8 is a schematic diagram illustrating a metal air cell 100 including an electrode formed of a metal oxide and a nitrogen-doped graphene electrode material, according to an embodiment of the present invention.

8, the metal air cell 100 includes an anode 110 as a cathode, a cathode 120 as an anode disposed facing the anode 110, and a cathode 120 disposed between the anode 110 and the cathode 120 And an electrolyte (130). The cathode 120 may further include a current collector 140 and a catalyst body 150. The anode 110 and the cathode 120 are disposed facing each other.

The metal air cell 100 generates electric power by using a reaction between metal and oxygen. The greatest advantage of the metal air cell 100 is that it uses oxygen existing in the natural world as an active material and possesses a very high theoretical energy density as compared with other secondary batteries and also possesses an affinity characteristic. In addition, since the metal air cell 100 does not contain a chemical oxidizer therein, there is no risk of explosion or fire, and the weight can be greatly reduced. In addition, it is very economical, superior in stability, and operates at low temperatures as compared with a fuel cell using hydrogen or alcohol.

The anode 110 may include a material that becomes a cation when it loses electrons at the time of discharging, and may include, for example, a metal and may include, for example, lithium, zinc, magnesium, aluminum, and calcium. In particular, lithium has a theoretical energy density of 11,140 Wh / kg, which is almost similar to that of gasoline at 13,000 Wh / kg. For reference, aluminum has a theoretical energy density of 8130 Wh / kg, calcium 4180 Wh / kg and zinc 1350 Wh / kg. Also, the anode 110 may be formed using a metal oxide and a nitrogen-doped graphene electrode material according to the technical idea of the present invention.

The cathode 120 is configured to use oxygen in the air, and can collect the oxygen. The metal air cell 100 can theoretically reduce the weight of the cathode 120 to zero or drastically because the cathode 120 can use oxygen in the air. Therefore, since the weight of the anode 110 can be increased by reducing the weight of the cathode 120, the weight ratio of the anode 110 to the total weight of the metal air cell 100 is increased, It can provide a high energy density per unit weight.

The cathode 120 may be formed using a metal oxide and a nitrogen-doped graphene electrode material according to the technical idea of the present invention. For example, at least one of the current collector 140 and the catalyst body 150 may be formed using a metal oxide and a nitrogen-doped graphene electrode material according to the technical idea of the present invention.

The electrolyte 130 is disposed between the anode 110 and the cathode 120 and may include an electrolytic material. The electrolyte 130 may include, for example, a sodium hydroxide (NaOH) solution or a calcium hydroxide (KOH) solution. Also, the electrolyte 130 may be composed of a solid-phase medium.

Hereinafter, power generation in the metal air battery 100 will be described. The anode 110 and the cathode 120 may be subjected to a discharge reaction and a charging reaction. The discharge reaction in the anode 110 and the cathode 120 is as follows. The charging reaction is such that the following reactions are directed to the opposite echo. In the following reaction formula, "M" may be a metal as a material constituting the anode 110.

<Anode Reaction>

M -> M ⁺ + e ^-

<Cathode reaction>

2 (M ⁺ + e ^- ) + O ₂ - > M ₂ O ₂

The positive ions 170 formed on the anode 110 through the discharge reaction are directed to the cathode 120 through the electrolyte 130. At this time, the electrons whose positive and negative ions are lost pass through the load 190 through separate conductors, thereby supplying power to the load 190 as a result.

Oxygen 180 from the outside is supplied to the cathode 120 and the cation 170 reacts with the oxygen 180 and the cathode 120 to form an oxide. At this time, electrons passing through the load 190 are supplied to the cathode 120 to form the oxide together.

On the other hand, at the time of charging, the oxide is decomposed, and the cation acquires electrons and returns from the cathode 120 to the anode 110 through the electrolyte 130.

9 is a schematic diagram illustrating a solid oxide fuel cell 200 including an electrode formed of a metal oxide and a nitrogen-doped graphene electrode material, according to an embodiment of the present invention.

9, the solid oxide fuel cell 200 includes an anode 210, a cathode 220 disposed opposite the anode 210, and an anode 210 disposed between the anode 210 and the cathode 220, And an electrolyte 230 which is a solid oxide. And optionally a buffer layer 240 disposed between the anode 210 and the electrolyte 230.

Solid oxide fuel cells of the fuel 200, as shown in electrochemical reaction is the following reaction scheme, a cathode 220, oxygen gas O ₂ has an anode reaction and the anode 210, changing the oxygen ions O ^2- of the (H ₂ or hydrocarbon ) And oxygen ions that have moved through the electrolyte.

<Reaction Scheme>

Anode reaction: 1/2 O ₂ + 2e ^- -> O ^2-

Cathode reaction: H ₂ + O ^2- -> H ₂ O + 2e ^-

In the cathode 220 of the solid oxide fuel cell 200, oxygen adsorbed on the surface of the electrode is dissociated and diffused to form a triple phase boundary where the electrolyte 230, the cathode 220 and the pores (not shown) The oxygen ions are converted into oxygen ions, and the generated oxygen ions are transferred to the anode 210, which is a fuel electrode, through the electrolyte 230.

In the anode 210 of the solid oxide fuel cell 200, the moved oxygen ions combine with the hydrogen contained in the fuel to generate water. At this time, hydrogen evolves electrons to hydrogen ions (H ⁺ ) and binds to the oxygen ions. The discharged electrons move to the cathode 220 through wiring (not shown) to change oxygen to oxygen ions. Through this electron transfer, the solid oxide fuel cell 200 can perform the battery function.

The solid oxide fuel cell 200 can be manufactured by using a conventional method known in the art, so a detailed description thereof will be omitted here. In addition, the solid oxide fuel cell 200 can be applied to various structures such as a tubular stack, a flat tubular stack, a planar type stack, and the like.

The solid oxide fuel cell 200 may be in the form of a stack of unit cells. For example, a unit cell (MEA) composed of an anode 210, a cathode 220, and an electrolyte 230 is stacked in series, and a separator plate (not shown) a stack of unit cells can be obtained with a separator interposed therebetween.

At least one of the anode 210 and the cathode 220 may be formed using a metal oxide and a nitrogen-doped graphene electrode material according to the technical idea of the present invention.

The electrolyte 230 is not particularly limited as long as it can be generally used in the art. For example, the electrolyte 230 may be a stabilized zirconia based system such as yttria stabilized zirconia (YSZ) and scandia stabilized zirconia (ScSZ); Ceria systems doped with rare earth elements such as samaria-doped ceria (SDC), gadolinia-doped ceria (GDC) and the like; Other LSGM ((La, Sr) (Ga, Mg) O ₃ ) system; And the like. In addition, the electrolyte 230 may include strontium or magnesium-doped lanthanum gallate.

The buffer layer 240 may be positioned between the anode 210 and the electrolyte 230 to provide a smooth contact. The buffer layer 240 may function to mitigate, for example, crystal lattice distortion between the anode 210 and the electrolyte 230. The buffer layer 240 may comprise, for example, LDC (La _0.4 Ce _0.6 O _{2 -δ} ). The buffer layer 240 may be omitted as an optional component.

FIG. 10 is a schematic diagram illustrating a solid oxide acceptance cell 300 including an electrode formed of a metal oxide and a nitrogen-doped graphene electrode material, according to an embodiment of the present invention.

10, the solid oxide acceptance cell 300 includes an anode 310, a cathode 320 disposed opposite the anode 310, and an anode 310 disposed between the anode 310 and the cathode 320, And an electrolyte 330 which is a conductive solid oxide. The cathode 320 may be referred to as a hydrogen electrode because it is in contact with hydrogen gas, and the anode 310 may be referred to as an oxygen electrode in contact with oxygen gas.

The electrochemical reaction of the solid oxide water electrolytic cell 300 is performed by an anode reaction in which water (H ₂ O) in the cathode 320 is converted into hydrogen gas (H ₂ ) and oxygen ions (O ^2- ) And an anode reaction in which the oxygen ions that have been moved through the electrolyte 330 are converted into oxygen gas (O ₂ ). This reaction is opposite to the reaction principle of a typical fuel cell.

<Reaction Scheme>

Cathode reaction: H ₂ O + 2e ^- -> O ^2- + H ₂

Anode reaction: O ^2- -> 1/2 O ₂ + 2e ^-

When power is applied to the solid oxide electrolytic cell 300 from the external power supply 340, electrons are supplied from the external power supply 340 to the solid oxide electrolytic cell 300. The electrons react with water supplied to the cathode 320 to generate hydrogen gas and oxygen ions. The hydrogen gas is discharged to the outside, and the oxygen ions are transferred to the anode 310 through the electrolyte 330. The oxygen ions transferred to the anode 310 lose electrons and are converted into oxygen gas and discharged to the outside. The electrons flow to the external power source 340. Through this electron transfer, the solid oxide electrolytic cell 300 can electrolyze water to form hydrogen gas at the cathode 320 and oxygen gas at the anode 310.

At least one of the anode 310 and the cathode 320 may be formed using a metal oxide and a nitrogen-doped graphene electrode material according to the technical idea of the present invention.

The electrolyte 330 is not particularly limited as long as it can be generally used in the art. The electrolyte 330 may include the same material as the electrolyte 230 of the solid oxide fuel cell 200 described above with reference to FIG. 9, or may have the same structure.

[Example]

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The above embodiments are not intended to limit the scope of the present invention.

The graphite pieces and the metal balls were charged to a ball mill apparatus (Pulverisette 6, Fritsch) under a nitrogen atmosphere. The loaded graphite piece was a product of Alfa Aesar, natural graphite having a purity of 99.9995% and a size of 100 mesh (150 μm or less), and the total charge amount was 5 g. The ball mill device was constructed of a 500 mL internal volume stainless steel material. The metal ball was 5 mm in diameter, 500 g in weight, and made of stainless steel.

The ball mill apparatus was sealed and filled with nitrogen gas to a level of 8 bar to form a nitrogen atmosphere. The filling was carried out five times with filling and discharging using nitrogen gas.

In the ball mill, the graphite and the metal ball were rotated at a speed of 500 rpm for 48 hours to ball-mill the graphite. By means of this ball mill, the graphite was pulverized to form graphene doped with metal and nitrogen.

The metal and nitrogen-doped graphene were dispersed in dimethylformamide (DMF) as a solvent, and polyacrylonitrile (PAN) as a polymer material was dissolved in the dimethylformamide to form a spinning solution . The spinning solution was electrospun by using the electrospinning apparatus described above to form a mesh structure.

Then, the mesh structure was stabilized so that the polymer constituting the mesh structure could form a ring structure. The stabilization treatment was carried out in an air atmosphere at a temperature of about 280 DEG C for about 1 hour. The rate of temperature rise to the temperature of the stabilization treatment was 2 ° C / min.

Then, the mesh structure having the ring structure formed therein was carbonized. The carbonization treatment was performed in a nitrogen gas atmosphere at a temperature of about 1000 캜 for about 1 hour. The rate of temperature rise to the temperature of the carbonization treatment was 2 ° C / min.

Then, the carbon nanotubes were subjected to activation treatment. The carbonization treatment was carried out in a 100% carbon dioxide gas atmosphere at a temperature of about 800 DEG C for about 1 hour. The rate of temperature rise up to the temperature of the activation treatment was 5 ° C / min.

According to the above-described method, the graphene electrode material doped with a metal oxide and nitrogen includes a mesh structure composed of carbon, graphene bonded to the mesh structure, and doped with a metal oxide and nitrogen. The graphene may be exposed to the surface of the mesh structure.

11 and 12 are SEM micrographs showing a metal oxide and nitrogen-doped graphene electrode material prepared according to a temporary example of the present invention.

Referring to FIG. 11, there is shown a photograph of a mesh structure formed by electrospinning according to the above-mentioned method after stabilization treatment. The mesh structure includes meshes having a width in the range of 100 nm to 1000 nm even after the stabilization process. Also, in FIG. 11, nets having widths of 239.0 nm, 553.9 nm, and 848.8 nm are exemplarily shown. After such stabilization, a network structure having a relatively different thickness width can be identified. Such a network structure can form a network structure with a smaller and consistent thickness through the following carbonization treatment.

Referring to FIG. 12, the stabilized mesh structure according to the above-described method is carbonized. It can be seen that the structure of the mesh structure remains after the carbonization treatment. The network structure includes nets having a width in the range of 100 nm to 1000 nm after the carbonization treatment. Further, in FIG. 12, nets having a width of 195.5 nm, 200.4 nm, 265.2 nm, 269.6 nm and 341.2 nm are exemplarily shown. Through this carbonization treatment, it can be confirmed that the value of the width of the network structure is decreased, and it can be confirmed that the uniformity is increased.

FIG. 13 is a transmission electron microscope photograph showing a metal oxide and nitrogen-doped graphene electrode material manufactured according to a temporary example of the present invention.

FIG. 13 is a photograph of the carbonized mesh structure according to the above-described method of FIG. 12 after activation treatment. It can be seen that graphene is distributed on the outer side of the network structure as shown by dark gray. Therefore, the catalytic activity can be increased as the graphene is exposed to the surface of the mesh structure.

For example, in the development of zinc metal air cells, the slow oxygen reduction reaction is becoming the biggest problem. That is, in the battery discharge reaction, the OH ^- ion consumption rate at the zinc cathode is much larger than the OH ^- ion production rate at the cathode, so that the OH ^- ion concentration in the electrolyte is rapidly lowered, have. Therefore, in the field of secondary batteries, it is required to develop a material having a rapid oxygen reduction reaction.

FIG. 14 is a graph illustrating an oxygen reduction reaction of a metal oxide and a nitrogen-doped graphene electrode material manufactured according to an embodiment of the present invention. The graph of FIG. 14 was measured by a Rotating Ring Disk Electrode (RRDE) measurement method in a 0.1 M KOH electrolyte. The electrode was made using carbon.

Referring to Figure 14, an embodiment of the present invention (denoted as "ACT CNF-N5") has a disk current (i _disk ) value that is similar to that of a platinum catalyst (denoted "20 wt% Pt / C & , Which is analyzed to have almost similar oxygen reduction characteristics. Therefore, it can be seen that the embodiment of the present invention has very excellent oxygen reduction reaction characteristics. In addition, embodiments of the present invention can also be used with comparative examples ("CNF-N0", "CNF-N3", "CNF-N5", and "CNF-N10") in which the nitrogen is doped and the metal oxide is not doped into the graphene , The graph shows a current value having a large absolute value under a voltage having a large absolute value, so that doping of the metal oxide with graphene improves the oxygen reduction reaction characteristic.

An embodiment of the present invention means that as the metal oxide is doped into the graphene, the oxygen reduction reaction starts at a lower voltage than the comparative examples, and more current can be generated at the same voltage. Embodiments of the present invention showed disk current (i _disk ) values in the range of about -6 to -7 as the absolute value of the voltage increased. The oxygen reduction reaction characteristic of this embodiment means that the embodiment of the present invention provides a quick oxygen reduction reaction and can generate a large amount of current. A good catalyst for an oxygen reduction reaction must have an oxygen reduction reaction that starts at a lower voltage and generates a lot of current under the same voltage. Therefore, the metal oxide and nitrogen-doped graphene electrode materials of the present invention can be excellent catalysts for the oxygen reduction reaction.

Since the graphene electrode material doped with the metal oxide and nitrogen can provide long-term stability and exhibits excellent performance of oxygen reduction reaction, it is possible to increase the activity of the battery, increase the stability, It can reduce the price.

The graphene electrode material doped with the metal oxide and nitrogen may be used as an electrode material of a metal air cell, a solid oxide fuel cell, and a solid oxide water-dissolving cell.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. Will be apparent to those of ordinary skill in the art.

1: graphene doped with a metal and nitrogen, 2: carbon atom, 3: nitrogen atom,
4, 41, 42, 43: metal atom
1000: electrospinning device, 10: spinning solution tank, 20: spinning nozzle,
30: spinning nozzle tip, 40: external power source, 50: collector substrate, 60: spinning solution,
100: metal air cell, 110: anode, 120: cathode, 130: electrolyte,
The present invention relates to a method for producing a catalyst,
200: solid oxide fuel cell, 210: anode,
220: cathode, 230: electrolyte, 240: buffer layer,
300: solid oxide electrolytic cell, 310: anode, 320: cathode,
330: electrolyte, 340: external power supply,

Claims (20)

Forming a metal and nitrogen doped graphene;
Forming a structure using the metal and nitrogen-doped graphene; And
Heat treating the structure to form a graphene electrode material doped with a metal oxide and nitrogen,
The step of forming the structure using the metal and nitrogen-doped graphene may include:
Mixing the metal and nitrogen-doped graphene with a polymer to form a spinning solution; And
And spinning the spinning solution using an electrospinning method to form a mesh structure,
The step of heat treating the structure to form a graphene electrode material doped with a metal oxide and nitrogen,
Stabilizing the mesh structure so that the polymer of the mesh structure forms a ring structure;
Carbonizing the mesh structure having the annular structure formed thereon; And
Activating the carbonized mesh network structure;
&Lt; / RTI &gt; The method according to claim 1,
The step of forming the metal and nitrogen-doped graphene comprises:
Charging graphite and a metal ball into a metal container;
Forming an interior of the metal container in a nitrogen atmosphere; And
Milling the graphite by ball milling using the metal balls to form graphene doped with a metal and nitrogen;
&Lt; / RTI &gt; The method of claim 2,
Wherein the graphite comprises a powder having a size of 10 mesh to 1000 mesh. The method of claim 2,
The metal ball and the metal container may be made of a metal such as stainless steel, Fe, Cr, Ni, Sc, Ti, V, Mn, (Cu), zinc (Zn), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), rubidium (Ru) (Au), cadmium (Cd), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir) , Or an alloy thereof. &Lt; / RTI &gt; The method of claim 2,
Wherein the metal doped to the graphene is provided from the metal ball, the metal container, or both. The method of claim 2,
The step of forming the metal container in a nitrogen atmosphere may include repeatedly performing the step of filling and discharging the metal container with nitrogen gas, and finally filling the metal container with nitrogen gas. Way. The method according to claim 1,
The metal doped in the graphene may be arranged to interpose between the carbon atoms constituting the graphene or may be arranged to substitute the nitrogen atom bonded to the carbon atom to bond with the carbon atom, Wherein the graphene electrode material is disposed on the surface of the substrate. delete The method according to claim 1,
Wherein the stabilizing step is performed at a temperature in the range of 250 DEG C to 350 DEG C in an air atmosphere. The method according to claim 1,
Wherein the carbonization step is performed at a temperature in the range of 900 占 폚 to 1100 占 폚 in an inert atmosphere. The method according to claim 1,
Wherein the activating step is performed at a temperature in the range of 700 DEG C to 900 DEG C in a carbon dioxide atmosphere. The method according to claim 1,
The stabilizing step is carried out in an air atmosphere at a temperature of 280 DEG C for 1 hour,
The carbonization step is carried out at a temperature of 1000 캜 for 1 hour in a nitrogen gas atmosphere,
Wherein the activating step is performed at a temperature of 800 DEG C for 1 hour in a carbon dioxide atmosphere. The method according to claim 1,
Wherein the metal doped in the graphene forms a metal oxide in the stabilization step, in the carbonization step, or in both steps. The method according to claim 1,
The polymer may be selected from the group consisting of polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), polyurethane, polyether urethane, cellulose acetate, cellulose acetate butyrate , Cellulose acetate propionate, polymethyl acrylate (PMA), polyvinyl acetate (PVAc), polyacrylonitrile (PAN), polyperfuryl alcohol (PPFA), polystyrene, polyethylene oxide (PEO), polypropylene oxide Wherein the at least one material is at least one selected from the group consisting of PPO, polycarbonate (PC), polyvinyl chloride (PVC), polycaprolactone, polyvinyl fluoride, and polyamide. delete delete delete delete delete delete

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