KR20100042672A - Electrode of supercapacitor manufactured by electrospinning and method for manufacturing the same - Google Patents

Abstract

PURPOSE: An electrode for a super capacitor and a manufacturing method thereof are provided to simplify a manufacturing process for an electrode by directly spraying an electrode material to a current collector. CONSTITUTION: An electrodes(11,12) for a super capacitor comprises a current collector and an electrode material. A spinning solution is formed by mixing precursor, polymer, and solvent of the metal oxide. The polymer comprises a carbon component. The spinning solution is sprayed to the current collector. The electrode material is obtained by heat-processing the spinning solution. The electrode material is made of the metal oxide and the carbon component.

Description

Electrode of Supercapacitor Manufactured by Electrospinning And Method for Manufacturing The Same}

The present invention relates to an electrode for a supercapacitor capacitor manufactured using electrospinning, and a method of manufacturing the same. More particularly, the present invention relates to a method of manufacturing a supercapacitor capacitor by mixing a precursor of a metal oxide with a polymer material, followed by electrospinning to a current collector. The present invention relates to an electrode for an ultracapacitor manufactured by using electrospinning to increase an electric storage capacity, and a method of manufacturing the same.

Ultracapacitors are also referred to as Electric Double Layer Capacitors (EDLC), Ultracapacitors or Supercapacitors.

Ultracapacitors are largely classified into electron double layer capacitors (EDLC) and oxidized / reduced capacitors (Pseudo capacitors).

The electric double layer capacitor accumulates electric charge by generating an electric double layer on the surface, while the oxidation / reduction capacitor accumulates electric charge by oxidation and reduction reaction together with the electric double layer formed on the surface of the electrode material. There is an advantage to accumulate.

Ultracapacitors use electrostatic characteristics, so the number of charge / discharge cycles is almost infinite and can be used semi-permanently compared to batteries using electrochemical reactions. That's it.

Due to the characteristics of such ultracapacitors, which cannot be realized with conventional batteries, their application fields are gradually expanding throughout the industry.

In particular, in the field of developing next-generation environmentally friendly vehicles such as electric vehicles (EVs), hybrid electric vehicles (HEVs), or fuel cell vehicles (FCVs), their utility as energy buffers is increasing day by day. have.

In other words, the ultracapacitor is used together with the battery as an auxiliary energy storage device, so that the instantaneous supply and absorption of energy is in charge of the supercapacitor, and the average vehicle energy is in charge of the battery, thereby improving the efficiency and energy of the overall vehicle system. Effects such as extending the life of the storage system can be expected.

In addition, it can be used as an auxiliary power source in portable electronic components such as mobile phones or video recorders, and its importance and use are greatly increased.

The electrode material of the ultracapacitor having such a characteristic uses activated carbon having a large specific surface area, a conductive polymer, a metal oxide, and the like. The ultracapacitor using the material as an electrode has advantages and disadvantages in terms of its characteristics.

For example, metal oxide electrodes have a high specific capacity, but when the electrode thickness is increased, the redox reaction is limited to the surface area, which leads to a sharp decrease in capacity. An activated carbon electrode has the advantages of low cost and high output characteristics. The storage capacity is relatively low, and the conductive polymer electrode has advantages in terms of diversification of the shape of the electrode due to polymer properties, manufacturing process, and storage capacity, but has a disadvantage in that its life is relatively short.

Metal oxides used as the metal oxide electrodes include ruthenium oxide, cobalt, nickel oxide, tungsten oxide, and the like.

Among the ruthenium oxides, many studies have been carried out by expressing a high specific capacity of 1000F / g or more, but as the high unit cost of ruthenium (20,000 won / g) and material is not environmentally friendly and many metal oxides, Due to the drawback that its characteristics vary greatly depending on the thickness, it is currently used only for special purposes such as military purposes, which is a non-commercial use, and research on thinning is being conducted.

Therefore, while researches on metal oxides that can replace the ruthenium oxide are being actively conducted, researches on manganese oxide, nickel oxide, cobalt oxide, and the like are in progress, and in particular, interest in manganese oxide is increasing.

The manganese oxide is environmentally friendly without being less than half the price of ruthenium oxide, and expresses a relatively high specific capacity close to 400 F / g although somewhat different depending on the synthesis method and experimental conditions.

As a technique for manufacturing an electrode of an ultracapacitor using such a manganese oxide, Patent No. 701627 discloses a method for producing a metal oxide-containing nanoactive carbon fiber and an electrode for a super capacitor using the nanoactive carbon fiber obtained therefrom. It is.

Disclosed in Patent hydrated manganese oxide (MnO _x · nH ₂ O) In the example manganese acetate by the reaction of (manganese acetate) and the oxidant is potassium permanganate (potassium permanganate) to 0.1M, 0.15M manganese by the reaction formula as the formula (1) Obtain a mixed solution of oxides.

_{KMnO 4 + 1.5 Mn (OAc)} 2 · 4H 2 O -> 2.5 MnO 2 · nH 2 O

The manganese oxide mixed solution was stirred for 3 hours, and the mixture was uniformly mixed by sonication, and then powder was obtained by vacuum filtration and vacuum drying to grind using a mortar and pestle.

The powder of the pulverized manganese oxide is polytetrafluoroethylene (PTFE; polytetrafluoroethylene), styrene butadiene rubber (SBR; Styrene butadiene rubber), polyvinylidene fluoride-hexafluoropropylene (PVdF-co-HFP; polyvinylidene fluoride It is mixed with a binder such as -co-hexafluoropropylene) and a solvent to coat the current collector. That is, a slurry or powder made of a manganese oxide electrode material, a binder, and a solvent is coated / compressed on a current collector to prepare an electrode through a drying process.

In this case, the current collector is limited to a metal having a smooth surface because the slurry or powder should be coated by tape casting and rolling and formed to have a uniform thickness.

However, in order to form the electrode of the ultracapacitor in the same manner as described above, it takes a lot of chemical treatment process and time, and there is a problem in that the resistance of the electrode is increased because a polymer-based binder having no conductivity is added.

On the other hand, Patent No. 649092 discloses a metal oxide-based supercapacitor composed of metal oxide coated titanium oxide ultrafine fibers and a method of manufacturing the same.

In this patent, in order to manufacture an electrode using the least amount of expensive ruthenium oxide, first, the titanium oxide precursor and the polymer solution are electrospun on a titanium metal plate used as a current collector, and then sintered to obtain a high specific surface area porous oxidation on the current collector. The process of preparing the board | substrate with which the titanium ultra-fine fiber matrix layer was formed, and electroplating ruthenium oxide on the said board | substrate is employ | adopted.

However, as a result of confirming the capacitance of the titanium oxide electrospun into the titanium current collector and undergoing the sintering process, the titanium oxide itself does not have a faradaic reaction and thus does not have a capacity behavior. Therefore, the titanium oxide itself is a capacitor electrode. Rather than using it, it can be seen that it is intended to manufacture a supercapacitor while using a minimum amount of ruthenium oxide by increasing the specific surface area. In other words, the process of forming titanium oxide by electrospinning was not related to the function implementation of the capacitor.

In addition, the electrode introduced in the patent has the following problems. That is, when the thickness of the titanium current collector is thin (100 μm or less), there is a problem in that breakage occurs even after a slight impact after the sintering process at 450 ° C., resulting in a weak stability of the finished product. In order to prevent the electrode from being broken in this way, it was confirmed that the current collector with a thickness of 127 μm was not easily broken, but there was still a problem in stability.

In addition, considering that commercialized capacitor electrodes have a thickness of 20 to 40 μm, there is a problem in that commercialization, that is, commercialization due to deterioration in volume specific capacity is poor due to its thickness of 3 to 6 times.

Accordingly, an object of the present invention is a method of forming an electrode for a capacitor through a simple heat and pressure treatment after electrospinning an electrode active material directly on a current collector, which is used for the production of an ultracapacitor without using an additional material such as a binder. An electrode for a capacitor and a method of manufacturing the same are provided.

Another object of the present invention is to form a metal oxide precursor directly on the current collector by electrospinning using a polymer material, and then heat-treat the polymer so that a pseudo capacitance according to the content ratio of carbon and metal oxide precursor according to carbonization of the polymer material is obtained. The present invention provides a hybrid type ultra-high capacitance capacitor electrode and a method of manufacturing the same.

Another object of the present invention is to form a metal oxide in a fibrous form by the electrospinning method to have a fibrous conductive network to improve the electrical conductivity, and ultracapacitors manufactured using electrospinning which can maintain a high capacity even at high scanning speed It is to provide an electrode and a manufacturing method thereof.

Another object of the present invention is to form a metal oxide irrespective of the material and structure of the current collector by the electrospinning method to vary the form according to the use, ultra-high capacity manufactured by using electrospinning that can be mass produced inexpensively An electrode for a capacitor and a method of manufacturing the same are provided.

In order to achieve the above object, the present invention provides a precursor of a metal oxide expressing a pseudo capacitance through a faradaic reaction, a polymer material having a carbon component, and a solvent for dissolving the polymer material. Preparing a spinning solution by mixing; Electrospinning the spinning solution on a current collector; And removing other components except metal oxides and carbon components by heat-treating the radiator radiated to the current collector, to provide an electrode manufacturing method for an ultra-capacitor using electrospinning.

The electrode manufacturing method for the ultracapacitor preferably further comprises electroplating a ruthenium oxide precursor on the surface of the electrode obtained according to the method.

The electrode manufacturing method for the ultracapacitor further includes the step of heat-treating for 30 minutes to 2 hours between 160 to 200 ° C. in an oxidizing atmosphere after electroplating the ruthenium oxide precursor. Preferably the heat treatment is at 175 ° C.

According to another aspect of the present invention, the present invention provides a precursor of at least one metal oxide that expresses pseudo capacitance through a Faradaic reaction, a polymer material, and a solvent for dissolving the polymer material. Preparing a spinning solution by mixing; Electrospinning the spinning solution to a current collector made of a porous foam; And removing other components except metal oxides and carbon components by heat-treating the radiator radiated to the current collector, to provide an electrode manufacturing method for an ultra-capacitor using electrospinning.

In addition, the method may further include a step of heat treatment after coating the ruthenium oxide precursor by the electroplating method or pyrolysis method after the heat treatment.

The current collector may be made of a porous nickel foam or a nickel plate, and the electrode may have a structure of carbon-metal oxide / ruthenium oxide / porous nickel foam or carbon-metal oxide / ruthenium oxide / porous nickel plate.

In addition, the spinning solution is composed of a plurality of spinning through a plurality of nozzles, respectively, or the spinning solution is composed of a plurality of spinning through one nozzle.

According to another aspect of the invention, the present invention is dissolved in the polymer material with a current collector, a polymer material having a precursor and a carbon component of a metal oxide expressing pseudo capacitance through a Faradaic reaction. It also provides an electrode for ultracapacitors using electrospinning, characterized in that it comprises an electrode material consisting of a metal oxide and a carbon component obtained by heat-treating the radiator electrospun to the current collector in a spinning solution mixed with a solvent for the purpose of do.

Preferably, the electroplating may further include an electroplated ruthenium oxide layer on the surface of an electrode material made of a metal oxide and a carbon component prepared as an electrode for an ultracapacitive capacitor to increase capacitance.

The heat treatment is carried out in an oxygen atmosphere, preferably after the heat treatment in a nitrogen atmosphere to improve the electrical conductivity.

The metal oxide is at least one selected from manganese oxide, nickel oxide, ruthenium oxide, iridium oxide, cobalt oxide, and tungsten oxide.

In addition, the current collector is made of any one selected from metal, carbon, and glass, and has a structure of any one of a plate, a metal-foil, a mesh, and a three-dimensional porous foam of the metal. Is done. It is preferable that the said metal consists of any of Ni, Ti, Al, Pt, Au, for example.

In addition, the current collector is made of at least one selected from a sheet of carbon or a foam of carbon.

The polymer material is at least one selected from polymer materials, such as PVAc, PAN, PI, PVdF, and polyvinyl alcohol (PVA).

The solvent is at least one selected from a solvent such as DMAc, DMF, acetone, ethanol, and tetrahydrofuran (THF).

In addition, the present invention further includes the step of pressing before the heat treatment to improve the contact between the precursor of the metal oxide and the current collector, heat pressurization is more preferred.

The ratio of the precursor of the metal oxide and the polymer material is 5 to 95: 95 to 5% by weight. When the content of the metal oxide is less than 5%, it has a low equivalent series resistance but is capable of redox reaction. Since the amount of the metal oxide is low, it has a low storage capacity. On the contrary, when the content of the metal oxide exceeds 95%, the storage capacity is large, but due to low electrical conductivity, it has a high equivalent series resistance and it is difficult to maintain the fibrous shape. In addition, the ratio of the precursor of the metal oxide and the polymer material is 60% to 80% by weight to 20% by weight is more preferable in terms of maximizing the storage capacity.

When the electrospinning is carried out at a voltage of less than 3000V, it is not possible to maintain a fine fibrous form to form a thin film, and if the voltage exceeds 50,000V, the length of the fiber becomes too short, so it is preferably made in a voltage range of 3,000 to 50,000V. In addition, as the distance between the spinning nozzle of the electrospinner and the current collector increases, the wire diameter of the spun fiber becomes thinner and the voltage value must be increased. Therefore, the electrospinning is performed in the state of being maintained within 5 cm to 60 cm of the fibrous formation. It is preferable.

The metal oxide precursor is any one selected from metal acetate, metal nitrate, metal chloride, and metal acetyl acetonate.

Accordingly, the present invention can produce an ultracapacitor by electrospinning the electrode material directly to the current collector and manufacturing the electrode for the capacitor without using additional material such as a binder through a simple heat press treatment.

In addition, the present invention is not only a manganese oxide, but also a precursor of a metal oxide expressing pseudo capacitance through a faradaic reaction such as nickel oxide, cobalt oxide, iridium oxide, etc. mixed with a polymer material and radiated by electrospinning After the heat treatment, the carbon component generated from the polymer material forms an electric double layer capacitor (EDLC) electrode, thereby producing an ultracapacitor having a high capacitance and a long lifetime.

Moreover, the electrospinning method according to the present invention has the advantage of being able to mass-produce a capacitor electrode at low cost.

In addition, since the metal oxide produced through electrospinning has an ultrafine fibrous shape due to the characteristics of electrospinning, it has an advantage of excellent electrical conductivity because it has a fibrous conductive network rather than a conductive form between particles and particles synthesized through chemical or electroplating. In addition, there is also an advantage that can easily manufacture the electrode for a hybrid capacitor in combination with heterogeneous metal oxides or carbon materials.

In order to fully understand the present invention, the advantages of the operability of the present invention, and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings showing preferred embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, the present invention will be described in more detail with reference to specific embodiments of the present invention. The following examples are merely provided to explain the present invention in more detail, whereby the technical scope of the present invention is not limited.

The present invention provides a precursor of a metal oxide that expresses pseudo capacitance through a Faradaic reaction, and a polymer material capable of electrospinning, that is, a polymer that can be dissolved in a solvent in order to manufacture an electrode for a very high capacity capacitor. After the preparation of the spinning solution by mixing a substance and a solvent capable of dissolving the polymer material, the current collector is electrospun.

In this case, the polymer material is capable of electrospinning all dissolved in a solvent, it is preferable to have a carbon that can act as activated carbon after heat treatment in the polymer material, a polymer that can be formed into a fibrous form when the electrospinning More preferred is that the material forms a conductive network after heat treatment.

The polymer material may be, for example, at least one selected from polymer materials such as PVAc, PAN, PI, PVdF, and polyvinyl alcohol (PVA).

Any precursor of the metal oxide may be used as long as it expresses a pseudo capacitance through a Faradaic reaction, and a precursor of one or more metal oxides may be mixed and spun together.

For example, the metal oxide precursor may be any one selected from metal acetate, metal nitrate, metal chloride, and metal acetyl acetonate.

The precursor of the metal oxide may be dissolved in a solvent together with the polymer material (for example, metal chloride), but most other precursors may not be dissolved but may be dispersed in a spinning solution in which the polymer material is dissolved.

Since the current collector is an electrode material is radiated by electrospinning, any material may be used as long as it is a conductive material, and any shape such as a plate, a foil, a mesh, and a foam may be used.

Therefore, the current collector is made of any one selected from metal, carbon, and glass, and has a structure of any one of a plate, a metal-foil, a mesh, and a three-dimensional porous foam of the metal. Is done. It is preferable that the said metal consists of any of Ni, Cu Ti, Al, Pt, Au, for example.

In addition, the current collector is made of at least one selected from a sheet of carbon or a foam of carbon.

The metal oxide precursor radiated together with the polymer material on the current collector is hot pressed to improve contact characteristics, and heat treatment is performed in an oxygen atmosphere to remove residues other than carbon and oxidize the metal oxide precursor in the polymer material. A heat treatment step is performed. Subsequently, it is good to perform nitrogen atmosphere heat processing to increase electrical conductivity as needed.

When the heat treatment process is completed as described above, the metal oxide obtained is made of at least one selected from, for example, manganese oxide, nickel oxide, ruthenium oxide, iridium oxide, cobalt oxide, and tungsten oxide.

Upon completion of the heat treatment process, an electric double layer capacitor (EDLC), a pseudo capacitor, and a hybrid capacitor in which EDLC and a pseudo capacitor are mixed according to the carbon content of the metal oxide and the carbon material according to carbonization. An electrode used as an electrode of any one of a hybrid capacitor is obtained.

The present invention provides a metal oxide compound for preparing an electrode, for example, manganese oxide (manganese acetate (manganese acetate), manganese nitrate (manganese nitrate), manganese acetyl acetonate (metal manganese acetyl acetonate) precursors A polymer such as polyvinylacetate (PVAc; polyvinylacetate) or polyacrylonitrile (PAN), which can maintain an electrospinning, preferably a fibrous form, is used as a dimethylformamide (DMF; It is dissolved in a solvent such as di-methylformamide) or dimethylacetamide (DMAc) and directly electrospun onto a substrate to be used as an electrode of a capacitor.

As shown in FIGS. 7, 8A and 8B, the electrospinner 10 used for the electrospinning is provided with a high voltage generator 5 by receiving the spinning liquid from at least one spinning liquid supply device 1a-1d. (+) Is applied to at least one of the spinning nozzles 3, 3a-3c and (-) is applied to the current collector disposed below, or vice versa.

The voltage applied for the electrospinning of the spinning liquid between the spinning nozzle and the current collector in the electrospinner is made in the voltage range of 3,000 ~ 50,000V, the interval between the spinning nozzle and the current collector of the electrospinner is set in the range of 5cm to 60cm do.

In this case, when the voltage is less than 3000V, the microfibers are not maintained and a thin film is formed. When the voltage is more than 50,000V, the length of the fiber becomes too short, so that the conductive network is hardly formed after the heat treatment. In addition, when the distance between the spinning nozzle and the current collector is far away from the range of 5cm ~ 60cm, the diameter of the spun fiber becomes thin and the voltage value must be increased so that it is difficult to form a fibrous shape, and in the case of proximity, the minimum voltage at which the solution is electrospun. There is a problem that can not be authorized. Therefore, it is preferable that the electrospinning is made in the state maintained in the range of 5 cm to 60 cm as possible.

In addition, the radiating nozzles 3, 3a-3c may reciprocate in the X and Y axes so that the entire radiator is uniformly radiated to the entire current collector positioned on the substrate 9 in the electrospinner 10. The substrate 9 to be positioned has a structure capable of reciprocating in the Y axis. Of course, the method of driving the spinning nozzles 3, 3a-3c and the substrate 9 to uniformly radiate the entire current collector may be performed in different ways.

Electrospinning method of the spinning liquid is a spinning nozzle (3a-) installed in the spinning unit 2 through the respective supply pipe (4a-4c) spinning liquid from each of the spinning liquid supply device (1a-1d) as shown in Figure 8a The individual spinning method of spinning by feeding to 3c) and the spinning liquid from the plurality of spinning liquid supply devices 1a-1d to each spinning nozzle 3 through one supply pipe 4 as shown in FIG. It may be made of one of the mixed spinning method is supplied by spinning.

As described above, the metal oxides produced through electrospinning can produce fine fibers that cannot be prepared through conventional chemical synthesis, and particularly polymers such as polyacrylonitrile (PAN) After the heat treatment, residues such as nitrile are sintered away and only carbon chains remain in a fibrous form to form an electric double layer.

This enables the formation of an electric double layer through the physical adsorption and desorption process originating on the carbon fiber together with the pseudo capacity through the redox reaction of the metal oxide.

In this way, when the content of the polymer capable of forming carbon fibers is greater than that of the metal oxide, it has a pseudo capacitance resulting from the metal oxide together with the basic electric double layer capacity. Likewise, when the content of the metal oxide is high, the pseudo capacity is dominant. Additionally has electric double layer capacity.

In this case, when the capacitor electrode is formed of the metal oxide alone without the carbon component, the equivalent series resistance (ESR) is increased to decrease the capacitance at high scanning speed (> 500 mV / s). On the contrary, when the electrode is formed by the carbon component alone, the life characteristics are excellent due to the stable physical properties of the carbon itself, but since the electric double layer on the surface is used, the storage capacity is smaller than that of the metal oxide through the redox reaction.

Accordingly, the present invention is to prepare an electric double layer capacitor (EDLC), a pseudo capacitor (EDLC), and a hybrid capacitor mixed with the EDLC and the pseudo capacitor by controlling the content of the metal oxide and the polymer material. Is possible.

In other words, the present invention uses the carbon material and the metal oxide having different advantages and disadvantages as described above, so that the life characteristics due to the stable physical properties of the carbon material and the high storage capacity of the metal oxide It is possible to manufacture an electrode for an ultracapacitor having a high capacitance since the capacity of the capacitor is reduced and the output characteristics are good even at a high scanning speed or a high discharge current.

The capacitor using an electrode of a carbon material and a metal oxide material includes a symmetrical hybrid capacitor in which each of the electrodes 11 and 12 separated by the separator 13 is made of carbon / metal oxide, as shown in FIG. 6A, As illustrated in FIG. 6B, each electrode separated by the separator 23 may be manufactured as an asymmetrical hybrid capacitor including the carbon electrode 21 and the metal oxide electrode 22.

Meanwhile, although each embodiment of the present invention describes an electrode using manganese oxide as a metal oxide, NiOx, RuOx, IrOx, CoOx, WOx, etc., which are known to express pseudo capacitance in addition to manganese oxide, are used. To form an electrode.

The current collector may use a metal plate, a metal-foil, a mesh, a foam, or the like, and may include a carbon sheet, a foam, and a carbon material. A glass substrate etc. can be used.

Here, the foam and the foam mentioned below mean a three-dimensional porous foam.

Hereinafter, the present invention will be described in more detail with reference to specific test examples of the present invention. The following examples are merely provided to explain the present invention in more detail, whereby the technical scope of the present invention is not limited.

1. First embodiment

10 wt% of manganese nitrate, a precursor of hydrated manganese oxide, maintains fibrous form, 5 wt% of polyacrylonitrile (PAN), which becomes a carbon material after heat treatment, and a solvent for dissolving the polymer Dimethyl acetate (DMAc; di-methylacetamide) was mixed at 85 wt% to prepare an electrospinning solution.

The electrospinning solution is placed in a raw material injection device of the electrospinner and the radiation voltage is adjusted to 14,600V.

Nickel foam (35 μm) is used as the current collector, and the distance between the current collector and the spinning nozzle of the electrospinner is 10 cm apart.

The spinning nozzle of the electrospinner is capable of reciprocating in the X and Y axes, and the substrate is evenly radiated throughout the substrate using the reciprocating movement in the Y axis.

In order to improve the contact characteristics between the manganese oxide precursor electrospun through the electrospinner as described above and the entire house, hot roll press is performed at 140 ° C.

Thereafter, the polyacrylonitrile, which is a polymer material, was heat-treated for 30 minutes in an oxygen atmosphere of 400 ° C to oxidize the metal oxide precursor with removal of residues other than carbon, and nitrogen of 800 ° C to increase the electrical conductivity. Heat treatment for 2 hours in the atmosphere.

The nickel foam electrode prepared through the above process was cut to 1 cm x 2.5 cm to prepare an electrode area of 1 cm x 1 cm.

In order to confirm the electrical properties of the electrode prepared as described above, using a PAR potentiometer of the electrode prepared as a three-electrode system (reference electrode; saturated calomel electrode, counter electrode; titanium plate, working electrode; nickel foam / manganese oxide) half Electrode experiments were performed. At this time, 1M sulfuric acid aqueous solution (H ₂ SO ₄ ) was used as the electrolyte.

As a result of measuring the electrical properties under the above conditions, a capacitance value of ²⁰ mF / cm ² was obtained at a scanning speed of 100 mV / s.

For reference, FIG. 1 (A) is a three-electrode system (Ag / AgCl (3M KCl, 0.196V vs. SCE) at a scanning speed of 20 mV / s in an electrolyte environment of 1 M sulfuric acid solution for an electrode made of manganese oxide. The results are shown.

2. Second Embodiment

The ruthenium oxide precursor was electroplated on the nickel foam / hydrated manganese oxide electrode prepared in Example 1 according to the following process.

A plating solution was prepared by dissolving 50 mM ruthenium trichloride and 0.1 M potassium chloride in distilled water, and stirring at a constant speed to maintain the solution at a temperature of 50 ° C. at a scanning speed of 300 mV / s between 0.25 and 1.45 V. It is cycled once and electroplated.

The electrode plated with ruthenium oxide is lightly washed with distilled water as above, and heat treated at 175 ° C. for about an hour. After ruthenium oxide electroplating and heat treatment, the experiment was carried out in the same manner as in the first embodiment.

As a result, a capacitance value of 76 mF / cm ² was obtained at a scanning speed of 100 mV / s, and when converted into a specific amount, it was confirmed that a high storage capacity of 1600 F / g was obtained at a scanning speed of 100 mV / s.

3. Third embodiment

First, manganese acetate, which is a raw material of hydrated manganese oxide; 5 wt% polyvinylacetate (PVAc; polyvinylacetate); 5wt% acetic acid catalyzing 5wt%, DMAc (di-methylacetamide); 85 wt% is dissolved and spun onto a Ti substrate having a thickness of 127 μm at an emission voltage of 14,600 V of the electrospinner.

As described above, it can be seen that the structure of manganese acetate / PVAc spun onto the Ti substrate has a fibrous structure as shown in the SEM photograph of FIG. 4.

At this time, the interval between the spinning nozzle of the electrospinner and the substrate is spaced apart by 10 cm. The electrospinning machine used in the present invention used the same spinner as the first embodiment. Thereafter, it is pressurized to 140 ° C. to improve the contact characteristics between the emitted manganese oxide precursor and the current collector.

Thereafter, heat treatment was performed for 30 minutes in an oxygen atmosphere of 400 ° C. to oxidize the metal oxide precursor together with the removal of the polymer, followed by heat treatment for 2 hours in an 800 ° C. nitrogen atmosphere.

The manganese oxide electrode prepared through the above process was used as a three-electrode system using a potentiometer to perform a half cell test (half cell test) to confirm the electrochemical characteristics. At this time, 1M sulfuric acid aqueous solution (H ₂ SO ₄ ) was used as the electrolyte.

As a result, a capacitance value of 18 mF / cm ² was obtained at a scanning speed of 100 mV / s.

4. Fourth embodiment

The ruthenium oxide was electroplated on the manganese oxide electrode prepared according to the third embodiment, heat treated at 175 ° C. for one hour, and electrochemical properties were confirmed in the same manner. Cyclic voltammetry confirmed the potential at 0.1V to 0.9V, resulting in a high capacitance value of 65mF / cm ² (1622F / g) at a scanning speed of 100mV / s.

For reference, FIG. 2 is a graph showing a change in storage capacity according to the sintering temperature of an electroplated ruthenium oxide electrode, and FIG. 2A is a test at a low scan rate (50 mV / s), and FIG. Was tested at a high scan rate (500 mV / s).

3 is a cyclic voltammogram for examining redox and charge / discharge characteristics of an electrospun manganese oxide / ruthenium oxide electrode according to the present invention. In the environment, the result of a test with a three-electrode system (Ag / AgCl (3M KCl, 0.196V vs. SCE) at a scanning speed of 20mV / s is shown.

In addition, the structure of the manganese oxide / ruthenium oxide electrode has a fibrous structure as shown in the SEM photograph of FIG.

5. Fifth Embodiment

Electrospinning by mixing 10.26 wt% manganese acetyl acetonate, a precursor of hydrated manganese oxide, 12.8 wt% polyvinylacetate (PVAc), and 76.94 wt% solvent dimethylformamide (DMF) Prepare a solution.

The electrospinning solution is placed in the raw material injection device of the electrospinner and the radiation voltage is adjusted to 15,000V. Nickel sheet (42 μm) is used as the current collector, and the distance between the current collector and the spinning nozzle of the electrospinner is evenly distributed to the entire substrate at a distance of 16 cm.

In order to improve the contact characteristics between the manganese oxide precursor electrospun through the electrospinner as described above and the current collector, the pressing plate was pressed for 30 seconds at a pressure of 0.5 ton / cm ² while applying a temperature of 30 ° C. to the upper and lower plates of the horizontal compressor. do.

Thereafter, heat treatment is performed for 30 minutes in an oxygen atmosphere at 300 ° C. to oxidize the metal oxide precursor with the removal of the polymer material.

The nickel sheet electrode prepared through the above process was cut to 1 cm x 2.5 cm to prepare an electrode area of 1 cm x 1 cm.

In order to confirm the electrical properties of the electrode prepared as described above, using a PAR potentiometer of the electrode prepared as a three-electrode system (reference electrode; saturated calomel electrode, counter electrode; titanium plate, working electrode; nickel foam / manganese oxide) half Electrode experiments were performed. At this time, 1M aqueous sodium sulfate solution (Na ₂ SO ₄ ) was used.

As a result of measuring the electrical properties under the above conditions, a capacitance value of 11.25 mF / cm ² was obtained at a scanning speed of 100 mV / s and 7.7 mF / cm ² at 2,000 mV / s.

When converted into specific amounts, it was confirmed that the high storage capacity of 245 F / g at a scanning speed of 100mV / s.

6. Comparative Example 1

A precursor solution (6 g of titanium propoxide, 2 g of acetic acid, 2 g of polyvinylacetate (PVAc), and 30 g of dimethylformamide (DMF; di-methylformamide) was added to a titanium metal plate current collector. Was set to 13,000V, and the distance between the spinning nozzle and the current collector plate was spaced at 10 cm, and the ultrafine titanium oxide fiber prepared by sintering after electrospinning was used as the substrate, and the area of the substrate was 1 cm x 1 cm.

As a result, a capacitance value of ³ mF / cm ² was obtained at a scanning speed of 100 mV / s.

For reference, (B) of FIG. 1 shows a result of testing a titanium oxide electrode using a three-electrode system (Ag / AgCl (3M KCl, 0.196V vs. SCE) at a scanning speed of 20 mV / s in an electrolyte environment of a 1 M sulfuric acid solution. It is shown.

7. Comparative Example 2

1.037 g of ruthenium trichloride (RuCl ₃ nH ₂ O) and 0.745 g of potassium chloride (KCl) are dissolved in deionized water to form a 100 ml solution.

The solution was immersed in a titanium oxide substrate for 20 minutes while maintaining the solution at 50 ° C. under constant magnetic stirring. Then, a ruthenium oxide was deposited by applying a current of 5 mA, and then washed with deionized water. At this time, the weight of the ruthenium oxide used the weight difference of the electrode before and after deposition.

A graph of circulating potential current was obtained in 0.5 M aqueous sulfuric acid solution, where the average current was obtained, and the capacitance was divided by the scanning speed. This storage capacity was divided again by the weight of ruthenium oxide to obtain a specific storage capacity. As a result of evaluating the characteristics, a capacity of 592 F / g was shown at a scanning speed of 10 mV / s.

The first and second comparative examples described above are made based on the method disclosed in Patent No. 649092, and the conditions of electrospinning not disclosed in Patent No. 649092 are made by applying the conditions of the present invention.

The second embodiment of the present invention shows a high capacitance of 1600 F / g at a scanning speed of 100 mV / s, and the second comparative example shows a capacity of 592 F / g at a scanning speed of 10 mV / s. When compared with the comparative example 2, it turns out that it shows remarkably high capacitance.

In addition, in the second comparative example, when the thickness of the titanium current collector is thin (100 μm or less), a phenomenon occurs that the chip is broken even after a slight impact after the sintering process at 450 ° C., so that the stability of the finished product is weak. In order to prevent the breakage, the result of checking the current collector with a thickness of 127 μm was not easily broken, but there was still a problem in stability.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electrode for a capacitor using electrospinning having a high accumulation capacity, high output, and long life, and to an electrode thereof. ) And the electrode of the hybrid capacitor in which the EDLC and the pseudo capacitor are mixed.

1 is a circulating current curve of a manganese oxide electrode (A) electrospun according to the present invention and a titanium oxide electrode (B) as a comparative example.

Figure 2 is a graph showing the change in storage capacity according to the low-speed scan (A) and high-speed scan (B) according to the sintering temperature of the electroplated ruthenium oxide electrode in accordance with the present invention.

3 is a cyclic current curve of an electrospun manganese oxide / ruthenium oxide electrode according to the present invention.

4 is a SEM photograph of manganese acetate / PVAc electrospun according to the present invention.

5 is a SEM photograph of a manganese oxide / ruthenium oxide electrode according to the present invention.

6A and 6B are exemplary diagrams for describing symmetric and asymmetric hybrid capacitor structures, respectively.

7 is a schematic configuration diagram showing an electrospinning apparatus used in the present invention.

8A and 8B are schematic configuration diagrams for explaining the single individual spinning and the mixed spinning method, respectively.

* Explanation of Signs of Major Parts of Drawings *

1a-1d: spinning solution supply unit 2: spinning section

3,3a-3c: spinning nozzle 4,4a-4c: supply pipe

5: high voltage generator 9: substrate

10: electric radiator

Claims (35)

Preparing a spinning solution by mixing a precursor of a metal oxide that expresses pseudo capacitance through a faradaic reaction, a polymer material having a carbon component, and a solvent for dissolving the polymer material; Electrospinning the spinning solution on a current collector; And Heat-treating the radiator radiated to the current collector to remove other components except metal oxide and carbon component; Electrode manufacturing method for an ultra-capacitor using an electrospinning comprising a. The method of claim 1, wherein the heat treatment is performed in an oxygen atmosphere. The method of manufacturing an electrode for an ultracapacitor using electrospinning according to claim 2, further comprising a post heat treatment in a nitrogen atmosphere after the oxygen atmosphere heat treatment. The method of claim 1, wherein the metal oxide is at least one selected from manganese oxide, nickel oxide, ruthenium oxide, iridium oxide, cobalt oxide, and tungsten oxide. The method of claim 1, wherein the current collector is any one selected from metal, carbon, and glass. 6. The candle according to claim 5, wherein the current collector is at least one selected from among a structure of a plate, a metal-foil, a mesh, and a foam of the metal. Electrode manufacturing method for high capacity capacitor. 6. The method of claim 5, wherein the current collector is at least one selected from a carbon sheet or a foam of carbon. 7. The method of claim 1, wherein the polymer material is at least one selected from PVAc, PAN, PI, PVdF, and polyvinyl alcohol (PVA). The method of claim 1, wherein the solvent is at least one selected from DMAc, DMF, acetone (Acetone), ethanol (Ethanol), THF (tetra hydro furan) manufacturing an electrode for an ultracapacitor using electrospinning Way. 2. The method of claim 1, further comprising the step of pressurizing before the heat treatment. According to claim 1, wherein the metal oxide precursor is any one selected from metal acetate (Metal acetate), metal nitrate (Metal nitrate), metal chloride (Metal chloride), metal acetyl acetonate (Metal acetyl acetonate) Electrode manufacturing method for an ultracapacitor using an electrospinning. The method of claim 1, wherein the ratio of the precursor of the metal oxide and the high molecular material is 5 to 95: 95 to 5% by weight. The method of claim 12, wherein the ratio of the precursor of the metal oxide and the polymer material is 60 to 80: 40 to 20% by weight. The method of claim 1, wherein the electrospinning is performed in a voltage range of 3,000 to 50,000V. The method of claim 1, wherein the electrospinning is performed in a state in which a distance between the spinning nozzle of the electrospinner and the current collector is maintained at 5 to 60 cm. The method according to any one of claims 1 to 15, further comprising coating ruthenium oxide by an electroplating method after the heat treatment. 17. The method of claim 16, further comprising heat-treating in an oxygen atmosphere after coating the ruthenium oxide. Preparing a spinning solution by mixing a precursor of at least one metal oxide expressing pseudo capacitance through a faradaic reaction, a polymer material, and a solvent for dissolving the polymer material; Electrospinning the spinning solution to a current collector made of a porous foam; And Heat-treating the radiator radiated to the current collector to remove other components except metal oxide and carbon component; Electrode manufacturing method for an ultra-capacitor using an electrospinning comprising a. 19. The method of claim 18, further comprising, after the heat treatment, coating the ruthenium oxide precursor by an electroplating method and then performing heat treatment. The method of claim 19, wherein the current collector is made of a porous nickel foam, The electrode is an electrode manufacturing method for an ultra-capacitor using electrospinning, characterized in that the structure of the carbon-metal oxide / ruthenium oxide / porous nickel foam. 19. The method of claim 18, wherein the spinning solution comprises a plurality of spinning solutions, and each of the spinning solutions is spun through a plurality of nozzles. 19. The method of claim 18, wherein the spinning solution comprises a plurality of spinning solutions and is radiated through one nozzle. With the whole house, Electrospinning a spinning solution comprising a precursor of a metal oxide expressing pseudo capacitance through a Faradaic reaction and a polymer material having a carbon component as a solvent for dissolving the polymer material is electrospun into the current collector An electrode for ultracapacitors using electrospinning comprising an electrode material comprising a metal oxide and a carbon component obtained by heat treatment of a radiator. The electrode of claim 23, wherein the metal oxide is at least one selected from manganese oxide, nickel oxide, ruthenium oxide, iridium oxide, cobalt oxide, and tungsten oxide. 24. The electrode of claim 23, wherein the current collector is any one selected from metal, carbon, and glass. 26. The candle according to claim 25, wherein the current collector is at least one selected from a structure of a plate, a metal-foil, a mesh, and a foam of the metal. Electrodes for high capacity capacitors. 27. The electrode of claim 25, wherein the current collector is at least one selected from a carbon sheet or a foam of carbon. The electrode of claim 23, wherein the polymer material is at least one selected from PVAc, PAN, PI, PVdF, and polyvinyl alcohol (PVA). 24. The electrode of claim 23, wherein the solvent is at least one selected from DMAc, DMF, Acetone, Ethanol, and THF (tetra hydro furan). The electrode of claim 23, wherein the ratio of the precursor of the metal oxide and the polymer material is 5 to 95: 95 to 5% by weight. 31. The electrode of claim 30, wherein the ratio of the precursor of the metal oxide and the polymer material is 60 to 80: 40 to 20% by weight. The method of claim 23, wherein the metal oxide precursor is any one selected from metal acetate, metal nitrate, metal chloride, and metal acetyl acetonate. An electrode for ultracapacitors using electrospinning. 33. The electrode as claimed in any one of claims 23 to 32, wherein the electrode material further comprises a ruthenium oxide layer coated on the surface thereof. The method of claim 33, wherein the current collector is made of a porous nickel foam, The electrode is an electrode for ultracapacitor using electrospinning, characterized in that the structure of the carbon-metal oxide / ruthenium oxide / porous nickel foam. 33. The electrode for ultracapacitor according to any one of claims 23 to 32, wherein the polymer material of the radiator is in the form of nanofibers.

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