KR102455689B1 - Cathode for energy storage device including metal oxide/twon-dimenstional nanostructure material-core/shell hybride particels and method of manufacturing the same - Google Patents

Abstract

The present invention comprises the steps of forming a mixture in which a catalyst metal is dispersed in a precursor or precursor compound of a two-dimensional nanostructure material, and generating microbubbles by irradiating the mixed solution with ultrasonic waves and using the energy generated when the microbubbles are collapsed. to decompose the precursor compound to synthesize the two-dimensional nanostructure material on the outer wall of the catalyst metal to form a catalyst metal/two-dimensional nanostructure material - including core/shell hybrid particles A cathode for an energy storage device and a method for manufacturing the same, comprising: oxidizing the catalyst metal to form a metal oxide/two-dimensional nanostructured material; preparing an ink by dispersing the metal oxide/two-dimensional nanostructure material in a dispersion; It is a technical gist to include the step of forming a negative electrode by applying the ink to the current collector. As a result, a two-dimensional nanostructure material is formed on the surface of the metal oxide by using an ultrasonic chemical method, thereby preventing the volume expansion of the metal oxide during charging and discharging of electrons and reducing the contact resistance.

Description

{Cathode for energy storage device including metal oxide/twon-dimenstional nanostructure material-core/shell hybrid particles and method of manufacturing the same}

The present invention relates to an anode for an energy storage device comprising a metal oxide/two-dimensional nanostructure material-core/shell hybrid particle and a method for manufacturing the same, and more particularly, to form a two-dimensional nanostructure material on the surface of a metal oxide, through which the electron To provide an anode for an energy storage device comprising a metal oxide/two-dimensional nanostructure material-core/shell hybrid particle capable of preventing volume expansion of metal oxides during charging and discharging and reducing contact resistance, and a method for manufacturing the same.

In line with industrial development and improvement of living standards, a high-performance energy storage device capable of realizing small size and high capacity along with research on weight reduction and low power consumption with the goal of miniaturization of portable electronic devices and continuous use for a long time is required. Accordingly, recently, lithium ion batteries or supercapacitors have been used as large-capacity power storage batteries such as electric vehicles and battery power storage systems, and small, high-performance energy sources such as portable electronic devices such as mobile phones, camcorders, and notebook computers.

Lithium-ion batteries have advantages such as high energy density, large capacity per area, low self-discharge rate, and long lifespan. In addition, since there is no memory effect, it is convenient for users to use and has a long lifespan. However, lithium ion batteries have problems in that low output characteristics and cycle characteristics are deteriorated due to reasons such as a long diffusion length of the negative electrode material and surface contamination due to reaction with an electrolyte.

A carbon-based anode was developed to solve the problems of the conventional lithium metal. The carbon-based negative electrode uses a method in which lithium ions are intercalated and released between the crystal planes of the carbon electrode during charging and discharging to perform oxidation and reduction reactions. However, the carbon-based anode has a limit in capacity increase, so it is difficult to play a sufficient role as an energy source for the rapidly changing next-generation portable electronic devices. Accordingly, in recent years, silicon (Si), tin (Sn), manganese (Mn), iron (Fe), nickel (Ni), or their oxides can reversibly occlude and release a large amount of lithium through a compound formation reaction with lithium. As it is known that it is possible, many studies are being conducted on it.

However, these metals cause a change in crystal structure during an alloy reaction with lithium, which accompanies volume expansion, generates an active material that is not released and is electrically isolated in the electrode, and intensifies the electrolyte decomposition reaction according to an increase in specific surface area. In addition, the volume change of the metal due to the reaction with lithium during charging and discharging is very large. Due to this, the negative active material is detached from the current collector during continuous charging and discharging, or the capacity decreases rapidly as the charge and discharge cycle progresses due to the increase in resistance due to a large change in the contact interface between the negative active materials, resulting in a short cycle life. There is a problem with losing. In order to solve this problem, research on forming a composite by mixing a carbon nanomaterial with a metal oxide is emerging.

Carbon nanomaterials have excellent mechanical properties to suppress the volume expansion of metal oxides, and have the advantage of lowering contact resistance due to their excellent electrical conductivity properties, so they have excellent high output and cycle characteristics. When metal oxide expands in volume, if it exceeds the elastic limit, charging and discharging do not proceed smoothly. However, when carbon nanomaterials are present on the outer surface of the metal oxide, even if the metal oxide expands in volume, the carbon nanomaterial suppresses volume expansion, so the elastic limit is not exceeded, and high output and cycle characteristics are improved through this.

As such, as a conventional technique for manufacturing a carbon nanomaterial and a metal oxide composite, a metal or a metal oxide on a functional group of graphene oxide such as 'Journal of American Chemical Society 132 (2010) 7472', 'Electrochimica Acta 64 (2012) 23', etc. Using the principle of supporting a metal oxide or forming a metal oxide and graphene through a hydrothermal reaction as in 'Korea Patent Office Laid-Open Patent Publication No. 10-2012-0113995 Nanocomposite Material, Method for Manufacturing Same, and Energy Storage Device Containing Same' The technique is known.

However, in the case of materials obtained through these methods, since graphene and metal oxide have separate structures, the carbon nanomaterial does not play a role in suppressing the volume expansion of the metal oxide. Therefore, even if it is applied to the negative electrode for the energy storage element, there is a problem in that the electrical conductivity does not increase because the contact resistance and volume expansion cannot be reduced.

Korean Patent Office Laid-Open Patent No. 10-2012-0113995 Korean Intellectual Property Office Registered Patent No. 10-1466310 Korean Intellectual Property Office Registered Patent No. 10-1493937

Therefore, it is an object of the present invention to form a two-dimensional nanostructured material on the surface of a metal oxide by using an ultrasonic chemical method, thereby preventing the volume expansion of the metal oxide during charging and discharging of electrons and reducing the contact resistance. To provide an anode for an energy storage device including a two-dimensional nanostructured material-core/shell hybrid particle and a method for manufacturing the same.

The above object is to form a mixture solution in which a catalyst metal is dispersed in a precursor or precursor compound of a two-dimensional nanostructure material, and to generate microbubbles by irradiating the mixed solution with ultrasonic waves, and the energy generated when the microbubbles are collapsed. In the method for manufacturing an anode for an energy storage device, comprising the step of decomposing the precursor compound to form a catalyst metal/two-dimensional nanostructure material by synthesizing the two-dimensional nanostructure material on the outer wall of the catalyst metal, the catalyst metal is oxidized to form a metal oxide/two-dimensional nanostructured material; preparing an ink by dispersing the metal oxide/two-dimensional nanostructure material in a dispersion; Metal oxide/two-dimensional nanostructure material, characterized in that it comprises the step of forming a negative electrode by applying the ink to the current collector-core/shell hybrid particle.

Here, the metal oxide is oxidized as a whole or only the outer surface is oxidized, and in the step of forming the metal oxide/two-dimensional nanostructure material, it is preferable to oxidize the catalyst metal by supporting it in a strong acid and stirring.

In addition, after the step of forming the mixed solution, it is preferable to further include the step of bubbling an inert gas in the mixed solution to control the inside of the mixed solution to an inert gas atmosphere.

The above object also includes a current collector; Metal oxide/two-dimensional nanostructure material-core/shell hybrid particle layer applied to the current collector, characterized in that it includes a metal oxide/two-dimensional nanostructure material-core/shell hybrid particle-containing anode for energy storage element .

Here, the hybrid particle layer is formed by synthesizing the two-dimensional nanostructure material on the outer wall of the catalyst metal using a mixture in which a catalyst metal is dispersed in a precursor or a precursor compound of the two-dimensional nanostructure material, and oxidizing the catalyst metal, , It is preferable to generate microbubbles by irradiating ultrasonic waves to the mixed solution to decompose the precursor compound using the energy generated when the microbubbles are collapsed to synthesize the two-dimensional nanostructure material on the outer wall of the catalyst metal. .

According to the above-described configuration of the present invention, a two-dimensional nanostructure material is formed on the surface of a metal oxide by using an ultrasonic chemical method, thereby preventing the volume expansion of the metal oxide during charging and discharging of electrons and reducing contact resistance. can

1 and 2 are flow charts of a method for manufacturing an anode for an energy storage device including a metal oxide/two-dimensional nanostructure material-core/shell hybrid particle according to an embodiment of the present invention;
3 is a scanning microscope photograph of nickel oxide / graphene-core / shell hybrid particles,
4 is a graph showing the current value according to the applied voltage for each scan speed of the negative electrode manufactured in Example,
5 is a graph showing the current value according to the applied voltage for each scan speed of the negative electrode prepared in Comparative Example 1,
6 is a graph showing the current value according to the applied voltage for each scan speed of the negative electrode prepared in Comparative Example 2,
7 is a graph showing the current value according to the applied voltage for each scan speed of the negative electrode prepared in Examples, Comparative Examples 1 and 2,
8 is a graph showing the impedance value of the negative electrode prepared in Example,
9 is a graph showing the impedance value of the negative electrode prepared in Comparative Example 1,
10 is a graph showing the impedance value of the negative electrode prepared in Comparative Example 2,
11 is a graph showing voltage comparison with time of negative electrodes prepared in Examples, Comparative Examples 1 and 2;

Hereinafter, an anode for an energy storage device including a metal oxide/two-dimensional nanostructure material-core/shell hybrid particle and a manufacturing method thereof according to the present invention will be described in detail with reference to the drawings.

As shown in FIGS. 1 and 2 , first, a mixed solution 10 in which a catalyst metal 13 is dispersed in a precursor or a precursor compound 11 of a two-dimensional nanostructure material is formed ( S1 ).

The catalyst metal 13 dispersed in the mixed solution 10 adsorbs atoms constituting the two-dimensional nanostructure material 15 and serves as a template for the synthesis of the two-dimensional nanostructure material 15 . Accordingly, the yield, crystallinity, and number of layers of the synthesized two-dimensional nanostructure material 15 vary according to the purity and type of the catalyst metal 13 . The higher the purity of the catalyst metal 13, the easier it is to adsorb the two-dimensional nanostructure material 15 surrounding the catalyst metal 13. It may further include the step of purifying and reducing the metal (13).

Here, the catalyst metal 13 refers to metal particles, copper (Cu), nickel (Ni), cobalt (Co), iron (Fe), silver (Ag), chromium (Cr), tungsten (W), platinum (Pt) ), palladium (Pd), silicon dioxide (SiO ₂ ), and an alloy including the same, or at least one selected from the group consisting of organometallic compounds such as metallocene.

The precursor compound 11 of the two-dimensional nanostructure material 15 refers to a precursor synthesized into the two-dimensional nanostructure material 15, and the two-dimensional nanostructure material 15 is formed around the catalytic metal 13 as a core. It is synthesized to surround it to form a shell. The two-dimensional nanostructure material 15 to be synthesized is synthesized from any one of the group consisting of high electrical conductivity graphene, hexagonal boron nitride (h-Boron nitride), a transition metal chalcogen compound, and a mixture thereof. Here, the transition metal chalcogen compound is represented by MX ₂ , where M is titanium (Ti), vanadium (V), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), hafnium ( Hf), tantalum (Ta), tungsten (W), and rhenium (Re), and X has a structure consisting of one of sulfur (S), selenium (Se), and tellurium (Te).

The precursor compound 11 of the two-dimensional nanostructure material 15 refers to each precursor compound capable of synthesizing graphene, hexagonal boron nitride, and a transition metal chalcogen compound.

Here, the precursor compound 11 for synthesizing graphene is a compound containing carbon, and acetic acid, acetone, acetyl acetone, anisole, benzene, and benzyl alcohol. (Benzyl alcohol), butanol, butanone, chlorobenzene, chloroform, cyclohexane, cyclohexanol, cyclohexanone, butylphthalate (Butyl phthalate), dichloroethane, diethylene glycol, diglyme, dimethoxyethane, dimethyl phthalate, dioxane, ethanol, Ethyl acetate, Ethyl acetoacetate, Ethyl benzonate, Ethylene glycol, Glycerin, Heptane, Heptanol, Hexane , Hexanol, Methanol, Methyl acetate, Methylene chloride, Octanol, Pentane, Pentanol, Pentanone, Tetra It is preferably selected from the group consisting of an organic solvent such as Tetrahydrofuran, toluene, and xylene, a solvent in which an organic monomer or polymer is dissolved, and a mixture thereof, but is not limited thereto.

The precursor compound 11 for synthesizing hexagonal boron nitride is selected from the group consisting of borazine, ammonia borane, and mixtures thereof.

In addition, the precursor compound 11 for synthesizing the transition metal chalcogen compound is ammonium tetrathiomolybdate ((NH ₄ ) ₂ MoS ₄ ), molybdenum chloride (MoCl ₅ ), molybdenum oxide (MoO ₃ ), Tungsten oxytetrachloride (WOCl ₄ ), 1,2-ethanedithiol (Hs(CH2) ₂ SH), ditertbutyl selenide (C ₈ H ₁₈ Se), diethyl selenide (C ₄ H ₁₀ Se) , Vanadium tetrakisdimethylamide (V(NMe ₂ ) ₄ ), tetrakisdimethylamidotitanium (Ti(NMe ₂ ) ₄ ), 2-methylpropanethiol (Bu ^t SH), tertbutyldisulfide (Bu ₂ ^t ) S ₂ ) and mixtures thereof.

Helium (He) or argon (Ar) gas is bubbled into the mixed solution 10 formed through the above method and material to control the inside of the solution to an inert gas atmosphere. When an active gas is present in the mixed solution 10, unwanted substances may be synthesized upon ultrasonic irradiation in a later step. In order to prevent this, a helium or argon inert gas is used to remove all of the active gas that may be present in the mixed solution 10. bubbling

The mixed solution 10 is irradiated with ultrasonic waves to synthesize the catalyst metal 13/two-dimensional nanostructure material 15-core/shell material (S2).

The catalyst metal 13 is irradiated with ultrasonic waves through the ultrasonic irradiator 30 to the mixed solution 10 in which the precursor or precursor compound 11 is dispersed to generate microbubbles. When the microbubbles are continuously irradiated with ultrasonic waves, the size gradually increases, and the pressure inside the microbubbles rises and eventually collapses. At this time, the generated local energy corresponds to a high temperature of 5000° C. or higher and causes decomposition of the precursor compound 11 present around the microbubbles. The precursor compound 11 decomposed using the energy generated when these microbubbles collapse is adsorbed to surround the outer wall of the catalyst metal 13 serving as a catalyst to form the nucleus of the two-dimensional nanostructure material 15 . And through the continuous decomposition and adsorption process of the precursor compound 11, the nucleus of the two-dimensional nanostructure material 15 expands, and the catalyst metal 13/two-dimensional nanostructure material 15 including the complete two-dimensional nanostructure material 15 ) is synthesized. The catalytic metal 13/two-dimensional nanostructure material 15 has a nano-sized catalytic metal 13 in the central region, and a two-dimensional nanostructured material 15 is synthesized on the outer wall of the catalytic metal 13. It consists of a shell structure. Here, the ultrasonic irradiator 30 used to generate ultrasonic waves uses a power of 100 to 200 W, and is preferably used within a range of 10 seconds to 6 hours.

In some cases, after synthesizing the catalyst metal 13/two-dimensional nanostructure material 15, the step of separating the catalyst metal 13/two-dimensional nanostructure material 15 from the mixed solution 10 may be further included. If there is a residual catalyst metal 13 or a residual precursor compound 11 that is not synthesized in the mixed solution 10, these may be removed to obtain a pure catalyst metal 13/two-dimensional nanostructure material 15. In this case, pure catalyst metal 13/two-dimensional nanostructure material 15 is obtained through the step of filtering the catalyst metal 13/two-dimensional nanostructure material 15 and then washing so as not to leave any residue.

The metal oxide 51/two-dimensional nanostructure material 15 is formed by oxidizing the catalyst metal 13 (S3).

A metal oxide 51 is formed by oxidizing the catalyst metal 13 present in the core among the catalyst metal 13/two-dimensional nanostructure material 15 synthesized in step S2 using an oxidation solvent 70 . If the catalytic metal 13 of the core is not oxidized, the catalytic metal 13 is oxidized to a metal oxide 51 so that electrons can move to the anode because the negative electrode of the secondary battery cannot be properly performed. In the metal oxide 51/two-dimensional nanostructure material 15 formed in this step, the inner core is in an oxidized state, and since the two-dimensional nanostructure material 15 is formed on the outside, the former is the metal oxide 51 as the core. ) and the two-dimensional nanostructure material 15, which is a shell, is inserted and detached. When the two-dimensional nanostructure material 15 is surrounded on the surface of the metal oxide 51 as described above, volume expansion of the metal oxide 51 due to the movement of electrons can be prevented.

As a method of oxidizing the catalyst metal 13, it is obtained by supporting the catalyst metal 13 in an oxidation solvent 70, synthesizing it through acid treatment, and then removing impurities using a repeated washing process and a centrifuge. Here, it is preferable to use a method of supporting the acid treatment in hydrogen peroxide and stirring it for 12 hours. Then, after neutralization using distilled water, filtering and washing are repeated. However, in addition to the acid treatment method using an oxidation solvent, oxidation of the catalyst metal 13 may be performed through heat treatment in an atmosphere containing an oxidizing gas. For example, oxidation of the catalyst metal 13 may be performed through heat treatment at a relative humidity of 90% and a temperature of 150°C.

Here, in the catalyst metal 13, the entire metal may be oxidized or only the outer surface of the metal may be oxidized. In order to control the degree of oxidation of the catalyst metal 13, a method of controlling the acid treatment time or controlling the concentration and temperature of the oxidation solvent 70 may be used.

The metal oxide 51/two-dimensional nanostructure material 15 is dispersed in the dispersion 53 to prepare the ink 50 (S4).

A highly conductive ink 50 is prepared by dispersing the purely obtained metal oxide 51/two-dimensional nanostructure material 15 in the dispersion 53 . Here, the metal oxide 51/two-dimensional nanostructure material 15 is preferably included in an amount of 40 to 80 parts by weight of the total 100 parts by weight of the ink 50 . When the amount is less than 40 parts by weight, the amount of the metal oxide 51 / two-dimensional nanostructure material 15 is insufficient, so that the electrical conductivity is significantly reduced, and when it exceeds 80 parts by weight, the metal oxide 51 / two-dimensional nanostructure material 15 Dispersibility is poor and coating performance is reduced due to increase in viscosity.

As the dispersion 53, a solvent typically used in the coating ink composition is used, and it is preferable to use a polar or non-polar solvent having a boiling point of 150 to 300°C.

The dispersion 53 contains at least one of terpineol, ethyl cellosolve, butyl cellosolve, carbitol, butyl carbitol, and glycerol. include

In the step of preparing the ink 50 , a binder for ink is added to additionally increase the viscosity and adhesiveness of the ink 50 . Specifically, the binder is an organic and inorganic material, and a cellulose-based resin such as methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, cellulose acetate butrate, carboxymethyl cellulose, hydroxyethyl cellulose, and polyurethane-based resins. and any one or a mixture of acrylic resins and silane coupling agents. Here, the silane coupling agent includes vinyl alkoxy silane, epoxy alkyl alkoxy silane, methacryloxy alkyl alkoxy silane, mercapto alkyl alkoxy silane, amino alkyl alkoxy silane, and the like.

Such a binder resin may be included in 0.5 to 5 parts by weight of the total 100 parts by weight of the ink 50, and when it is added in less than 0.5 parts by weight, the added amount is small, so the viscosity and adhesiveness are not greatly improved, and 5 parts by weight If it is exceeded, a phenomenon of remarkably reduced electrical conductivity occurs.

A negative electrode is prepared by applying the ink 50 to the current collector (S5).

The ink 50 prepared through step S4 is applied to the current collector for manufacturing the negative electrode of the energy storage element. As a method of applying the ink 50 to the current collector, a processing method such as coating, patterning, extruding, blasting, or spread may be used. Among them, it is most preferable to use a bar coating that can uniformly apply the ink 50 without empty spaces inside and on the surface by using a rolling bar.

The current collector used for the negative electrode is made of copper (Cu), aluminum (Al), platinum (Pt), gold (Au), nickel (Ni), titanium (Ti), iron (Fe), molybdenum (Mo), and mixtures thereof. It is preferably selected from the group consisting of, but is not limited thereto.

Hereinafter, Examples and Comparative Examples of the present invention will be described in more detail.

<Example>

1-1. reduction of nickel particles

Nickel (Ni) particle powder is added to 4M hydrochloric acid (HCl) and stirred for 10 minutes to remove organic matter and oxide film contaminated on the surface. Thereafter, hydrochloric acid remaining in the reduced nickel particles is removed through filtration and washing processes.

1-2. Preparation of mixed solution composed of nickel/carbon compound

5 g of the nickel particles reduced through method 1-1 are added to 250 ml of xylene to form a mixed solution, and argon (Ar) gas is bubbled to control the inside of the solution to an inert gas atmosphere do.

1-3. Graphene Synthesis Using Ultrasound

A horn ultrasonicator is inserted into the mixed solution prepared in 1-2 above, and ultrasonic waves of 200 W power and 9 cycles are applied to synthesize graphene for 30 minutes. Graphene is formed around the nickel particles to form a nickel/graphene-core/shell structure. Thereafter, residual xylene is removed through filtration and washing processes.

1-4. Preparation of Nickel Oxide/Graphene-Core/Shell Hybrid Nanoparticles

Nickel is oxidized by supporting and stirring 5 g of nickel/graphene-core/shell hybrid particles prepared by method 1-3 above in 6M hydrogen peroxide for 12 hours. Thereafter, residual hydrogen peroxide is removed through a filtration and washing process.

1-5. Manufacture of high concentration ink based on nickel oxide/graphene-core/shell hybrid particle

5 g of nickel oxide/graphene nanoparticles prepared by method 1-4 are dispersed in dimethyl formamide (DMF) to prepare a high-concentration ink. Ethyl cellulose and terpineol are added thereto to further prepare a high-viscosity paste and stirred.

1-6. Manufacture of anodes for energy storage devices

The high-concentration ink prepared in steps 1-5 is deposited on the copper substrate, which is a current collector, by using bar coating to finally prepare a negative electrode.

<Comparative Example 1>

2-1. Nickel oxide particle production

Nickel oxide was prepared by immersing 5 g of nickel particles in 6M hydrogen peroxide for 12 hours and stirring. The hydrogen peroxide remaining in the prepared nickel oxide is removed through filtration and washing processes.

2-2. Reduced graphene production

After synthesizing high-purity graphite flakes (99.9995%) in a powder state through acid treatment, the impurities are removed using a repeated washing process of aqueous solution and a centrifuge. Sodium perchlorate (Sodium perchlorate, NaClO ₄ ) or potassium permanganate (Potassium permanganate, KMnO ₄ ) is added to concentrated nitric acid or sulfuric acid and oxidized by stirring at room temperature for 48 hours. Then, it is neutralized using distilled water, and sodium perchlorate or potassium permanganate is removed through filtration and washing. After treating the oxidized graphite solution for 2 hours using a homogenizer, graphene oxide is prepared. Hydrazine (H ₂ N ₂ ) is used to reduce the prepared graphene oxide, thereby obtaining reduced graphene.

2-3. Preparation of nickel oxide/reduced graphene composite ink

Ink is prepared by dispersing 5 g of nickel oxide and 0.5 g of reduced graphene prepared by the methods 2-1 and 2-2, respectively, in dimethylformamide. In addition, ethyl cellulose and terpineol are added and stirred to prepare a high-density ink.

2-4. Manufacture of anodes for energy storage devices

A negative electrode is prepared by depositing the high-concentration ink prepared in the method of 2-3 on the copper substrate as the current collector through bar coating.

<Comparative Example 2>

3-1. Nickel oxide particle production

Nickel oxide was prepared by supporting and stirring 5 g of nickel particles in 6M hydrogen peroxide for 12 hours. The hydrogen peroxide remaining in the nickel oxide is removed by filtering and washing the nickel oxide.

3-2. Nickel oxide particle ink production

An ink is prepared by dispersing the nickel oxide prepared in step 3-1 in dimethylformamide. In addition, ethyl cellulose and terpineol are added and stirred to prepare a high-concentration ink.

3-3. Manufacture of anodes for energy storage devices

A negative electrode is manufactured by depositing the ink prepared through the method of 3-2 on a copper substrate, which is a current collector, using bar coating.

A scanning electron microscope image of the negative electrode for the energy storage element coated with the nickel oxide/graphene-core/shell hybrid particle prepared in the above example can be seen in FIG. 3 .

4 to 6 are experimental data of a cathode for an energy storage element according to Examples and Comparative Examples, and are graphs showing current values according to applied voltages for each scan rate.

4 is data measured using the negative electrode obtained through the example. Here, 5mV/s represents the rate at which a voltage is applied, meaning that a voltage of 5mV per second is applied, and 1000mV/s means that a voltage of 1000mV is applied per second. Also, in the line formed according to the same applied voltage, the upper line represents the amount of current when charging from 0 to 2.5V, and the lower line represents the amount of current when discharging from 2.5 to 0V. As can be seen from the graph, it can be seen that the current increases as the applied voltage for each scan speed increases. Also, as the rhombus shape made up of lines representing charge and discharge is wider and closer to a rectangle, it means that the capacitor has a larger charge and discharge capacity.

5 is a graph showing Comparative Example 1, wherein the negative electrode is a nickel oxide-reduced graphene composite ink and is experimental data of the negative electrode for the energy storage device. Comparing FIG. 5 with FIG. 4 , it can be seen that the rhombus shape is a shape away from the rectangle, and the area is also reduced compared to the embodiment of FIG. 4 . That is, it can be seen that Comparative Example 1 has a smaller charge and discharge capacity than that of Example.

6 is a graph showing Comparative Example 2, where the negative electrode is a graph in which an energy storage element negative electrode made of ink containing only nickel oxide is tested. 6 shows that the charging and discharging capacity is smaller than that of FIGS. 4 and 5 .

7 is a graph comparing FIGS. 4 to 6, wherein the current value of Example (NiO _x /Graphene) is higher than the current value of Comparative Example 1 (NiO _x -reduced graphene oxide) and Comparative Example 2 (NiO _x ) that can be checked

8 to 10 are graphs illustrating impedances according to Examples and Comparative Examples.

8 is a graph confirming the impedance of the embodiment, that is, the AC resistance value through two cycles. In the graph, the closer the starting point is to 0Ω, the smaller the interfacial resistance between the cathode and the material applied to the cathode, and the wider the contact gap, the higher the resistance. 8, since the starting point is close to 0Ω, it can be seen that the negative electrode coated with the material of the present invention has a small impedance value. In addition, it represents the resistance according to the movement of electrons in the material applied to the current collector, and the steeper the slope of the graph, the lower the resistance. 8, it can be seen that the slope is steeper than that of the comparative example.

9 is a graph showing the impedance value of Comparative Example 1, it can be confirmed that the starting point is close to 500Ω. This means that the contact resistance is large. Also, it can be seen that the slope of the graph is very gentle at the beginning, which means that the resistance in the material is large.

10 is a graph showing the impedance value of Comparative Example 2, it can be seen that the contact resistance is large as the starting point is close to 1000Ω, as in FIG. It can be seen that the resistance is large.

11 is a graph showing the voltage when repeatedly charged and discharged, and the slope of the graph and the charge and discharge capacity are inversely proportional to each other. That is, the gentle slope means that the capacitor has a large capacity. In Comparative Examples 1 and 2, it can be confirmed that the charge and discharge capacities are small because the slope is large. It can be seen that larger than

Conventionally, when a material mixed with a metal oxide and a carbon compound is manufactured as a cathode, the carbon nanomaterial does not play a role in suppressing the volume expansion of the metal oxide because the metal oxide and the carbon compound have separate components. However, in the present invention, since the surface of the metal oxide 51 is surrounded by the two-dimensional nanostructure material 15, if the cathode is manufactured through this, the volume expansion of the metal oxide 51 can be prevented during the charge and discharge of electrons. , as well as the effect of reducing the contact resistance can be obtained.

10: mixed solution
11: precursor compound
13: catalyst metal
15: two-dimensional nanostructured material
30: ultrasonic irradiator
50: ink
51: metal oxide
70: oxidation solvent

Claims (15)

Forming a mixture solution in which a catalyst metal is dispersed in a precursor or precursor compound of a two-dimensional nanostructure material, and generating microbubbles by irradiating the mixed solution with ultrasonic waves, and using the energy generated when the microbubbles collapse, the precursor compound In the method for manufacturing a negative electrode for an energy storage element comprising the step of decomposing the two-dimensional nanostructure material on the outer wall of the catalyst metal to form a catalyst metal / two-dimensional nanostructure material,
oxidizing the catalyst metal to form a metal oxide/two-dimensional nanostructured material;
preparing an ink by dispersing the metal oxide/two-dimensional nanostructure material in a dispersion;
Metal oxide/two-dimensional nanostructure material-core/shell hybrid particles comprising the step of forming a negative electrode by applying the ink to the current collector. The method of claim 1,
The metal oxide is a metal oxide / two-dimensional nanostructure material, characterized in that the entire oxidation or only the outer surface is oxidized - a method of manufacturing an energy storage element negative electrode comprising a core / shell hybrid particles. The method of claim 1,
The step of forming the metal oxide / two-dimensional nanostructure material,
Metal oxide/two-dimensional nanostructure material-core/shell hybrid particle, characterized in that the catalyst metal is supported in a strong acid and oxidized through stirring. The method of claim 1,
The step of forming a negative electrode by applying the ink to the current collector,
Metal oxide/two-dimensional nanostructure material, characterized in that it is made through a coating, patterning, extruding, blasting, or spread method - Energy storage including core/shell hybrid particles A method for manufacturing a magnetic cathode. The method of claim 1,
Before the step of forming the mixture,
Metal oxide/two-dimensional nanostructure material, characterized in that it further comprises the step of refining and reducing the catalyst metal-core/shell hybrid particle-containing anode manufacturing method for an energy storage device. The method of claim 1,
After the step of forming the mixture,
Metal oxide/two-dimensional nanostructure material, characterized in that it further comprises the step of bubbling an inert gas in the mixed solution to control the inside of the mixed solution to an inert gas atmosphere - Method of manufacturing a negative electrode for an energy storage device including core/shell hybrid particles . The method of claim 1,
The two-dimensional nanostructure material is metal oxide / two-dimensional nanostructure material, characterized in that selected from the group consisting of graphene, hexagonal boron nitride (h-Boron nitride), a transition metal chalcogen compound, and mixtures thereof- A method for manufacturing an anode for an energy storage device comprising core/shell hybrid particles. The method of claim 1,
The catalyst metal is copper (Cu), nickel (Ni), cobalt (Co), iron (Fe), silver (Ag), chromium (Cr), tungsten (W), platinum (Pt), palladium (Pd), silicon Dioxide (SiO ₂ ) and a mixture thereof, characterized in that selected from the group consisting of metal oxide / two-dimensional nanostructure material-core / shell hybrid particles comprising a cathode manufacturing method for an energy storage device. The method of claim 1,
The ultrasonic wave is a metal oxide/two-dimensional nanostructure material, characterized in that it is generated by a power of 100 to 300W-core/shell hybrid particle-containing anode manufacturing method for an energy storage device. delete delete delete delete delete delete

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