KR102639923B1 - Manufacturing method of nitrogen doped electrode active material with reduced chemical amount by using surface modifier, and supercapacitor using the same and method of manufacturing thereof - Google Patents

Abstract

To modify the surface of the electrode active material, a pretreatment process using a surface modifier containing a doping source is performed, and then nitrogen doping is performed using a nitrogen source, thereby fixing nitrogen functional groups on the carbon surface even with a small amount of chemicals. A method for manufacturing nitrogen-doped activated carbon using a surface modifier that can facilitate this process and reducing the amount of chemicals, a supercapacitor using the same, and a method for manufacturing the same are disclosed.

Description

A method of manufacturing a nitrogen-doped electrode active material with a reduced chemical amount using a surface modifier, a supercapacitor using the same, and a method of manufacturing the same METHOD OF MANUFACTURING THEREOF}

The present invention relates to a method for manufacturing a nitrogen-doped electrode active material with a reduced chemical content using a surface modifier, a supercapacitor using the same, and a method for manufacturing the same. More specifically, the present invention relates to a method for manufacturing a nitrogen-doped electrode active material using the same, and more specifically, to a method for manufacturing a nitrogen-doped electrode active material using the same, and more specifically, to a method for manufacturing a nitrogen-doped electrode active material using the same, and more specifically, to a method for manufacturing a nitrogen-doped electrode active material using a surface modifier, and a method for manufacturing the same. After performing a pretreatment process using a surface modifier, nitrogen doping is performed using a nitrogen source to increase the amount of chemical using a surface modifier that can facilitate the fixation of nitrogen functional groups on the carbon surface even with a trace amount of chemical. It relates to a method of manufacturing a reduced nitrogen-doped electrode active material, a supercapacitor using the same, and a method of manufacturing the same.

Among next-generation energy storage devices, supercapacitors are attracting attention as next-generation energy storage devices due to their fast charging and discharging speeds, high stability, and eco-friendly characteristics. A typical supercapacitor consists of a porous electrode, a current collector, a separator, and an electrolyte.

A supercapacitor is also called an Electric Double Layer Capacitor (EDLC) or an ultra-capacitor, and is a pair of charge layers (with different signs) at the interface between an electrode and a conductor and an electrolyte impregnated therein. It is a device that does not require maintenance as the deterioration due to repetition of charging and discharging operations is very small by using the created electric double layer.

Accordingly, supercapacitors are mainly used as IC (integrated circuit) backup for various electrical and electronic devices. Recently, the uses of supercapacitors have expanded and are being widely applied to toys, solar energy storage, and HEV (hybrid electric vehicle) power sources.

Such a supercapacitor generally consists of two electrodes, an anode and a cathode, impregnated with an electrolyte solution, a separator made of a porous material interposed between these two electrodes to enable only ion conduction and to insulate and prevent short circuits, and an electrolyte solution. It has a unit cell consisting of a gasket to prevent liquid leakage, insulation and short circuit prevention, and a metal cap as a conductor to package them. It is completed by stacking one or more unit cells (usually 2 to 6 in the case of coin type) configured as above in series and combining the two terminals of the anode and cathode.

The performance of a supercapacitor is determined by the electrode active material, electrolyte, etc., and in particular, major performance such as storage capacity is largely determined by the electrode active material. Therefore, recently, research has been actively conducted on the development of high-output supercapacitors that can exhibit high-output characteristics by improving the electrical conductivity of electrode active materials.

Related prior literature includes Republic of Korea Patent Publication No. 10-1448211 (announced on October 8, 2014), which describes a nitrogen-doped porous carbon material and its manufacturing method.

The purpose of the present invention is to perform a pretreatment process using a surface modifier containing a doping source to modify the surface of the electrode active material, and then perform nitrogen doping using a nitrogen source to improve the surface of the carbon surface even with a small amount of chemicals. To provide a method for manufacturing a nitrogen-doped electrode active material with a reduced amount of chemicals using a surface modifier that can facilitate fixation of nitrogen functional groups, a supercapacitor using the same, and a method for manufacturing the same.

To achieve the above object, a method of manufacturing a nitrogen-doped electrode active material with a reduced chemical content using a surface modifier according to an embodiment of the present invention includes the steps of (a) modifying the surface of the electrode active material using a surface modifier; (b) reacting the surface-modified electrode active material with a nitrogen source and boiling the surface-modified electrode active material to attach the nitrogen source to the surface of the surface-modified electrode active material; and (c) heat-treating the electrode active material to which the nitrogen source is attached at 500 to 1,200° C. to form a nitrogen-doped electrode active material.

The step (a) includes (a-1) mixing the surface modifier and the electrode active material in a solvent to form a suspension; (a-2) stirring the suspension at 5 to 15°C for 4 to 8 hours at a speed of 300 to 600 rpm; and (a-3) filtering the stirred suspension and drying it for 5 to 25 hours to obtain a surface-modified electrode active material.

In step (a-1), the surface modifier includes at least one selected from cetyl trimethyl ammonium bromide (CTAB) and ammonium lauryl sulfate (ALS).

The surface modifier is added in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the electrode active material.

In step (a-2), the stirring is performed using ultrasonication.

The electrode active material includes one or more selected from graphene, carbon nanotubes, and activated carbons.

The step (b) includes (b-1) dissolving the nitrogen element in a solvent; (b-2) heating the mixed solution in which the nitrogen source is dissolved to 100 to 120°C; and (b-3) adding the surface-modified electrode active material to the heated mixed solution, stirring the mixture, and then boiling the mixture at 100 to 120°C.

In step (b-1), the nitrogen source is polyacrylonitrile, polyaniline, tetramethylethylenediamine, polypyrrole, polyrhodanine, and melamine. , urea, purine, adenine, guanine, hypoxanthine, xanthine, theobromine, and caffeine. .

After step (b-3), (b-4) drying the mixed solution in which the bath is completed at 100 to 120°C may be further included.

In step (c), the heat treatment is performed at 500 to 1,200°C for 1 to 10 hours in an inert gas atmosphere.

After step (c), the nitrogen-doped electrode active material is doped with 0.1 to 3.0 atomic% of nitrogen based on 100 atomic% of the total electrode active material.

In order to achieve the above object, a supercapacitor using a nitrogen-doped electrode active material with a reduced chemical content using a surface modifier according to an embodiment of the present invention includes a negative electrode including a negative electrode active material, a conductive material, and a binder; a positive electrode disposed spaced apart from the negative electrode and including a positive electrode active material, a conductive material, and a binder; a separator disposed between the cathode and the anode to prevent short circuit between the cathode and the anode; and an electrolyte solution impregnated in the negative electrode and the positive electrode, wherein at least one of the negative electrode active material and the positive electrode active material is prepared by reducing the amount of chemicals using a surface modifier prepared according to any one of claims 1 to 11. A nitrogen-doped electrode active material for a supercapacitor is used, and the nitrogen-doped electrode active material is characterized in that the nitrogen is doped at 0.5 to 3.0 atomic% based on 100 atomic% of the total electrode active material.

The supercapacitor exhibits a capacity retention rate of more than 90% under a current density condition of 50 mA/cm ² .

In order to achieve the above object, the method of manufacturing a supercapacitor using a nitrogen-doped electrode active material with a reduced chemical amount using a surface modifier according to an embodiment of the present invention is (a) mixing the electrode active material, conductive material, and binder in a dispersion medium to form a supercapacitor. Preparing a composition for capacitor electrodes; (b) compressing the supercapacitor electrode composition to form an electrode, coating the supercapacitor electrode composition on a metal foil to form an electrode, or pressing the supercapacitor electrode composition with a roller to form a sheet. Forming an electrode by attaching it to a metal foil or current collector; (c) drying the resulting electrode-shaped product to form a supercapacitor electrode; and (d) using the supercapacitor electrode as an anode and a cathode, disposing a separator between the anode and the cathode to prevent short circuit between the anode and the cathode, and impregnating it with an electrolyte solution, including (a) ) In the step, the electrode active material is an electrode active material for a nitrogen-doped supercapacitor in which the amount of chemicals is reduced using the surface modifier prepared according to any one of claims 1 to 11, and the nitrogen-doped electrode active material is characterized in that the nitrogen is doped at 0.5 to 3.0 atomic% based on 100 atomic% of the total electrode active material.

The supercapacitor exhibits a capacity retention rate of more than 90% under a current density condition of 50 mA/cm ² .

The method of manufacturing a nitrogen-doped electrode active material with a reduced chemical amount using a surface modifier according to the present invention, the supercapacitor using the same, and the method of manufacturing the same include modifying the surface of the electrode active material using a surface modifier containing a doping source. After performing the pretreatment process, the nitrogen functional group is attached by boiling in a bath, and then the nitrogen functional group is fixed through heat treatment, making it easy to fix the nitrogen functional group on the carbon surface even with the use of a small amount of chemicals.

In addition, the method of manufacturing a nitrogen-doped electrode active material using a surface modifier according to the present invention with a reduced amount of chemicals, a supercapacitor using the same, and the method of manufacturing the same are used to reduce the amount of chemicals, so that when an excessive amount of doping source is used, the electrode of the supercapacitor is damaged due to residual chemicals. Slurry agglomeration that may occur during the manufacturing stage can be alleviated.

As a result, the method for manufacturing a nitrogen-doped electrode active material using a surface modifier according to the present invention with a reduced amount of chemicals, the supercapacitor using the same, and the method for manufacturing the same are capable of fixing nitrogen functional groups on the surface of the electrode active material even when a trace amount of chemicals is used. Since this can be done easily, manufacturing costs can be significantly reduced by reducing the amount of expensive chemicals used.

In addition, the method for manufacturing a nitrogen-doped electrode active material using a surface modifier according to the present invention with a reduced chemical content, the supercapacitor using the same, and the manufacturing method thereof improve electrical conductivity when the supercapacitor is manufactured using the nitrogen-doped electrode active material. This facilitates charge transfer of the electrolyte, enabling high output characteristics.

Therefore, a supercapacitor using a nitrogen-doped electrode active material in which the amount of chemicals is reduced using a surface modifier prepared by the method according to the present invention exhibits an excellent capacity retention rate of more than 90% under a current density condition of 50 mA/cm ² .

Figure 1 is a process flow chart showing a method of manufacturing a nitrogen-doped electrode active material with a reduced chemical amount using a surface modifier according to an embodiment of the present invention.
Figure 2 is a process flow chart showing a method of manufacturing a supercapacitor using a nitrogen-doped electrode active material in which the amount of chemicals was reduced using a surface modifier according to an embodiment of the present invention.
Figure 3 is a cross-sectional view showing a coin-type supercapacitor according to an embodiment of the present invention.
4 to 7 are schematic diagrams showing a wound-type supercapacitor according to another embodiment of the present invention.
Figures 8 and 9 are graphs showing the strength according to binding energy of the supercapacitor electrodes manufactured according to Example 1 and Comparative Examples 1 and 2.
Figure 10 is a graph showing the results of measuring specific capacitance values for each current density of supercapacitors manufactured according to Example 1 and Comparative Examples 1 to 2.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms. The present embodiments only serve to ensure that the disclosure of the present invention is complete and that common knowledge in the technical field to which the present invention pertains is provided. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

Hereinafter, with reference to the attached drawings, a method for manufacturing a nitrogen-doped electrode active material with a reduced chemical content using a surface modifier according to a preferred embodiment of the present invention, a supercapacitor using the same, and a method for manufacturing the same will be described in detail as follows.

Figure 1 is a process flow chart showing a method of manufacturing a nitrogen-doped electrode active material with a reduced chemical amount using a surface modifier according to an embodiment of the present invention.

Referring to Figure 1, the method for manufacturing a nitrogen-doped electrode active material with a reduced chemical amount using a surface modifier according to an embodiment of the present invention includes a surface modification step (S10), a water boil step (S20), and a heat treatment step (S30). do.

surface modification

In the surface modification step (S10), the surface of the electrode active material is modified using a surface modifier.

This surface modification step (S10) is a pretreatment process for producing a nitrogen-doped electrode active material with a small amount of chemicals when nitrogen doping using a nitrogen source. For this purpose, in the present invention, it is preferable to use a surface modifier containing a nitrogen doping source to modify the surface of the electrode active material. As such a surface modifier, it is preferable to use at least one selected from cetyl trimethyl ammonium bromide (CTAB) and ammonium lauryl sulfate (ALS), but is not limited thereto. In other words, anything other than CTAB and ALS that can be used as a surface modifier to facilitate fixation of surface functional groups can be used without limitation.

At this time, the surface modifier is preferably added in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the electrode active material. If the surface modifier is added in too small a quantity (less than 0.1 part by weight per 100 parts by weight of the electrode active material), there is a risk that the surface modification of the electrode active material may not be properly achieved. Conversely, if the surface modifier is added excessively, exceeding 10 parts by weight per 100 parts by weight of the electrode active material, it may act as a factor in increasing the amount of surface modifier used without any further surface modification effect, making it uneconomical.

In addition, the electrode active material may include one or more selected from graphene, carbon nanotubes, and activated carbon, but is not limited thereto. In other words, electrode active materials other than graphene, carbon nanotubes, and activated carbon can be used without limitation as long as they are used as electrode active materials for supercapacitors.

This surface modification step (S10) may include a suspension formation process, a stirring process, and a drying process.

First, in the suspension formation process, a surface modifier and an electrode active material are mixed in a solvent to form a suspension. Here, the solvent may be used without limitation as long as it can completely dissolve the surface modifier, and distilled water is preferably used.

Next, in the stirring process, the suspension is stirred at a speed of 300 to 600 rpm for 4 to 8 hours at 5 to 15°C. If the stirring speed is less than 300 rpm or the stirring time is less than 4 hours, uniform mixing between the surface modifier and electrode active material of the suspension may not be achieved, which may lead to difficulties in securing dispersion stability. On the other hand, if the stirring speed exceeds 600 rpm or the stirring time exceeds 8 hours, it is not economical because it only increases process cost and time without further increasing the effect.

It is desirable to carry out such stirring using ultrasonication.

Next, in the drying process, the stirred suspension is filtered and then dried for 5 to 25 hours to obtain a surface-modified electrode active material.

double boiler

In the double boiling step (S20), a nitrogen source is reacted with the surface-modified electrode active material to attach the nitrogen source to the surface of the surface-modified electrode active material.

This double boiling step (S20) includes dissolving the nitrogen source in the solvent, heating the mixed solution in which the nitrogen source is dissolved to 100 to 120°C, and adding the surface-modified electrode active material to the heated mixed solution and stirring it. After doing so, it may include a double boiling process at 100 to 120°C.

At this time, if the heating temperature is less than 100°C, there is a risk that the nitrogen source may not be completely dissolved in the solvent. Conversely, if the heating temperature exceeds 120°C, it is not economical because it only increases process cost and time without further increasing the effect.

Here, the nitrogen source is polyacrylonitrile, polyaniline, tetramethylethylenediamine, polypyrrole, polyrhodanine, melanin, urea, It contains at least one selected from purine, adenine, guanine, hypoxanthine, xanthine, theobromine, and caffeine.

In addition, the double boiling step (S20) may further include drying the mixed solution after the double boiling at 100 to 120°C. At this time, if the drying temperature is less than 100°C, sufficient drying may not occur, which may lead to difficulties in securing mechanical strength. Conversely, if the drying temperature exceeds 120°C, it may act as a factor that only increases manufacturing costs without further increasing the effectiveness, making it uneconomical.

heat treatment

In the heat treatment step (S30), the electrode active material to which the nitrogen source is attached is heat-treated at 500 to 1,200°C to form a nitrogen-doped electrode active material.

In this step, heat treatment is preferably performed in an inert gas atmosphere at 500 to 1,200°C for 1 to 10 hours, and a more preferable heat treatment temperature may be 800 to 1,000°C. During this heat treatment, it is preferable that the temperature increase rate is 1 to 5°C/min.

During this heat treatment, one or more types of inert gases among Ar, He, and N ₂ are used. In addition, during heat treatment, it is desirable to supply the inert gas at a rate of 200 to 700 cc/mm.

If the heat treatment temperature is less than 500°C or the heat treatment time is less than 1 hour, there may be difficulties in securing pores due to insufficient heat treatment. Conversely, if the heat treatment temperature exceeds 1,200°C or the heat treatment time exceeds 10 hours, it is undesirable because there is a risk that the nitrogen-doped electrode active material may be damaged due to excessive heat treatment.

Since the general method of manufacturing nitrogen-doped electrode active materials does not involve surface modification using a surface modifier, the nitrogen source is not well fixed on the surface of the electrode active material, and thus requires double boiling for a long time or using a large amount of nitrogen source to use an excessive amount of chemicals. . In addition, when manufacturing electrodes for supercapacitors using general nitrogen-doped electrode active materials, impurities resulting from excess chemicals generate repulsion between the current collector and the electrode slurry, making it difficult to manufacture coated electrodes.

To solve this problem, in the present invention, a method selected from cetyl trimethyl ammonium bromide (CTAB) and ammonium lauryl sulfate (ALS) containing a nitrogen doping source is used to modify the surface of the electrode active material. A pretreatment process using at least one surface modifier was introduced.

That is, in the present invention, the electrode active material is surface modified through a pretreatment process using a surface modifier containing a nitrogen doping source, then nitrogen functional groups are attached to the surface of the electrode active material through a double boiler, and then heat treatment is performed to transfer the nitrogen functional groups to the electrode active material. fixed to the surface.

As a result, in the present invention, the nitrogen functional group is attached by performing surface modification treatment using a surface modifier and then performing double boiling, so even if only a small amount of chemical is used during heat treatment for fixing the nitrogen functional group, nitrogen is attached to the surface of the electrode active material. Since it can be easy to fix the functional group, manufacturing costs can be significantly reduced.

After this heat treatment step (S30), the nitrogen-doped electrode active material may be doped with nitrogen at 0.5 to 3.0 atomic%, more preferably 0.5 to 1.5 atomic%, based on 100 atomic% of the total electrode active material. In addition, nitrogen-doped activated carbon has a specific surface area of 500 to 3,500 m2/g. If nitrogen is doped at a concentration of less than 0.5 atomic% based on the total 100 atomic% of the electrode active material, the concentration may be too low to properly exert the effect of improving the electrical conductivity of the electrode active material. Conversely, if nitrogen is excessively doped beyond a concentration of 3.0 atomic% for the total 100 atomic% of the electrode active material, it may act as a factor requiring excessive use of the nitrogen source without further increasing the effect, making it uneconomical. Can not do it.

The method of manufacturing a nitrogen-doped electrode active material with a reduced chemical content using a surface modifier according to the above-described embodiment of the present invention involves performing a pretreatment process to modify the surface of the electrode active material using a surface modifier containing a doping source. After attaching the nitrogen functional group in a double boiler, fixing the nitrogen functional group on the carbon surface can be facilitated by using only a small amount of chemicals by heat treatment to fix the nitrogen functional group.

In addition, the method of manufacturing a nitrogen-doped electrode active material in which the amount of chemicals is reduced using a surface modifier according to an embodiment of the present invention reduces the slurry that can be generated in the electrode manufacturing stage of a supercapacitor due to residual chemicals when an excessive amount of doping source is used due to the reduction in the amount of chemicals. Clumping may be alleviated.

As a result, the method for manufacturing a nitrogen-doped electrode active material with a reduced amount of chemicals using a surface modifier according to an embodiment of the present invention can make it easier to fix a nitrogen functional group on the surface of the electrode active material even if only a trace amount of the chemical is used, making it expensive. Manufacturing costs can be significantly reduced by reducing the amount of chemical used.

In addition, the method for manufacturing a nitrogen-doped electrode active material with a reduced chemical amount using a surface modifier according to an embodiment of the present invention facilitates charge transfer of the electrolyte solution by improving electrical conductivity when a supercapacitor is manufactured using a nitrogen-doped electrode active material. This makes it possible to demonstrate high output characteristics.

Therefore, a supercapacitor using a nitrogen-doped electrode active material with a reduced chemical content using a surface modifier manufactured by a method according to an embodiment of the present invention exhibits an excellent capacity retention rate of more than 90% under a current density of 50 mA/cm ^2. do.

Hereinafter, with reference to the attached drawings, a supercapacitor using a nitrogen-doped electrode active material with a reduced chemical content using a surface modifier according to an embodiment of the present invention and a method for manufacturing the same will be described.

Figure 2 is a process flowchart showing a method of manufacturing a supercapacitor using a nitrogen-doped electrode active material in which the amount of chemicals was reduced using a surface modifier according to an embodiment of the present invention.

As shown in Figure 2, the method of manufacturing a supercapacitor using a nitrogen-doped electrode active material with a reduced chemical content using a surface modifier according to an embodiment of the present invention includes forming a composition for a supercapacitor electrode (S110) in the form of an electrode. It includes a forming step (S120), a supercapacitor electrode forming step (S130), and an electrolyte impregnation step (S140).

Formation of compositions for supercapacitor electrodes

In the step of forming a composition for supercapacitor electrodes (S110), a composition for supercapacitor electrodes is prepared by mixing an electrode active material, a conductive material, and a binder in a dispersion medium.

The composition for supercapacitor electrodes includes an electrode active material, 1 to 20 parts by weight of a conductive material per 100 parts by weight of the electrode active material, 1 to 20 parts by weight of a binder per 100 parts by weight of the electrode active material, and 100 to 300 parts by weight of a dispersion medium per 100 parts by weight of the electrode active material. It is desirable to include wealth.

Since this composition for supercapacitor electrodes is in the form of a paste, uniform mixing (complete dispersion) may be difficult, and it can be mixed for a predetermined period of time (e.g., 10 minutes to 12 hours) using a mixer such as a planetary mixer. By stirring for a while, a composition for supercapacitor electrodes suitable for electrode production can be obtained. Mixers such as planetary mixers enable the preparation of uniformly mixed compositions for supercapacitor electrodes.

The electrode active material is used as one manufactured by the nitrogen-doped electrode active material manufacturing method in which the amount of chemicals is reduced using a surface modifier according to an embodiment of the present invention described with reference to FIG. 1.

As such, in the present invention, when an electrode for a supercapacitor is manufactured using a nitrogen-doped electrode active material in which the amount of chemicals is reduced using a surface modifier, there is a risk of repulsion between the current collector and the electrode slurry due to impurities due to the reduction in the amount of chemicals. This makes it easier to manufacture coated electrodes.

At this time, the nitrogen-doped electrode active material is doped with nitrogen at 0.5 to 3.0 atomic% based on 100 atomic% of the total electrode active material. Therefore, when a supercapacitor is manufactured using the nitrogen-doped electrode active material of the present invention, electric conductivity is improved to facilitate charge transfer in the electrolyte solution, enabling high output characteristics.

The binder is polytetrafluoroethylene (PTFE), polyvinylidenefloride (PVdF), carboxymethylcellulose (CMC), polyvinyl alcohol (PVA), and polyvinyl butyral (PVB). ; poly vinyl butyral), polyvinylpyrrolidone (PVP; poly-N-vinylpyrrolidone), styrene butadiene rubber (SBR; styrene butadiene rubber), polyamide-imide, polyimide, etc. One selected type or a mixture of two or more types can be used.

The conductive material is not particularly limited as long as it is an electronically conductive material that does not cause chemical changes. Examples include natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, Super-P black, carbon fiber, copper, nickel, Metal powders such as aluminum and silver or metal fibers can be used.

The dispersion medium may be an organic solvent such as ethanol (EtOH), acetone, isopropyl alcohol, N-methylpyrrolidone (NMP), propylene glycol (PG), or water.

Formed in the form of an electrode

In the forming step (S120), the supercapacitor electrode composition is pressed to form an electrode, the supercapacitor electrode composition is coated on a metal foil to form an electrode, or the supercapacitor electrode composition is pressed with a roller to form a sheet. It is made into a state and attached to a metal foil or current collector to form an electrode.

To describe an example of the forming step in the form of an electrode in more detail, the composition for supercapacitor electrodes can be molded by compression using a roll press molding machine. The purpose of the roll press forming machine is to improve electrode density and control the thickness of the electrode through rolling. It includes a controller that can control the thickness and heating temperature of the upper and lower rolls and the roll, and a winding device that can unwind and wind the electrode. It is made up of parts. The rolling process proceeds as the electrode in the roll state passes through the roll press, and then it is wound again in the roll state to complete the electrode. At this time, it is desirable that the pressing pressure of the press is 5 to 20 ton/cm2 and the temperature of the roll is 0 to 150°C.

In addition, looking at another example of forming in the form of an electrode, the composition for supercapacitor electrodes is coated on metal foil such as titanium foil (Ti foil), aluminum foil (Al foil), and aluminum etching foil (Al etching foil). Alternatively, the composition for supercapacitor electrodes can be pushed with a roller into a sheet (rubber type) and attached to a metal foil or metal current collector to form an electrode. Here, aluminum etching foil means aluminum foil etched into a concavo-convex shape.

Supercapacitor electrode formation

In the supercapacitor electrode forming step (S130), the resulting electrode-shaped product is dried to form a supercapacitor electrode.

The composition for supercapacitor electrodes that has gone through the press compression process goes through a drying process. The drying process is performed at a temperature of 100 to 350°C, preferably 150 to 300°C. At this time, if the drying temperature is less than 100°C, it is undesirable because evaporation of the dispersion medium is difficult, and if the drying temperature exceeds 350°C, it is undesirable because oxidation of the conductive material may occur. Therefore, it is preferable that the drying temperature is at least 100°C or higher and does not exceed 350°C. Additionally, the drying process is preferably carried out at the above temperature for 10 minutes to 6 hours. This drying process dries (evaporates the dispersion medium) the molded supercapacitor electrode composition and simultaneously binds the powder particles to improve the strength of the supercapacitor electrode.

On the other hand, when the electrode is formed in another example in the form of an electrode, it is preferable to dry at a temperature of 100 to 250°C, preferably 150 to 200°C.

Electrolyte impregnation

In the electrolyte impregnation step (S140), supercapacitor electrodes are used as the anode and cathode, a separator is placed between the anode and cathode to prevent short circuit between the anode and cathode, and the anode and cathode are impregnated with the electrolyte solution of the supercapacitor.

Here, the electrolyte of the supercapacitor may include a non-aqueous electrolyte and an ionic liquid added in an amount of 1 to 25 parts by weight based on 100 parts by weight of the non-aqueous electrolyte.

The coin-type supercapacitor manufactured through the above process (S110 ~ S140) can greatly improve the electrical conductivity of the electrode active material by applying an electrode active material co-doped with nitrogen and fluorine, facilitating charge transfer of the electrolyte solution, resulting in high output. characteristics can be demonstrated.

This will be described in more detail with reference to the attached drawings below.

Figure 3 is a cross-sectional view showing a coin-type supercapacitor according to an embodiment of the present invention.

In FIG. 3, reference numeral 190 is a metal cap as a conductor, reference numeral 160 is a separator made of a porous material for insulation and short circuit prevention between the anode 120 and the cathode 110, and reference numeral 192 is an electrolyte leak. It is a gasket for insulation and short circuit prevention. At this time, the anode 120 and the cathode 110 are firmly fixed by the metal cap 190 and adhesive.

The coin-type supercapacitor is disposed between the anode 120 and the cathode 110 and the anode 120 and the cathode 110 and includes a separator 160 to prevent short circuit between the anode 120 and the cathode 120. ) can be manufactured by placing an electrolyte in the metal cap 190, injecting an electrolyte between the anode 120 and the cathode 110, and then sealing it with a gasket 192.

The separator 160 is not particularly limited as long as it is a separator commonly used in the battery field, such as polyolefin, polyethylene, or polypropylene.

Meanwhile, FIGS. 4 to 7 are schematic diagrams showing a wound-type supercapacitor according to another embodiment of the present invention, and with reference to this, a method of manufacturing a wound-type supercapacitor according to another embodiment of the present invention will be described in detail.

The method of manufacturing the cathode and anode compositions for supercapacitors is the same as the method described above.

The cathode and anode compositions for supercapacitors are coated on metal foil such as copper foil, aluminum foil, or aluminum etching foil, or the composition for supercapacitor electrodes is applied with a roller. It is pushed into a sheet (rubber type) and attached to a metal foil or current collector to form the positive and negative electrodes.

The anode and cathode shapes that have gone through these processes undergo a drying process. The drying process is performed at a temperature of 100 to 350°C, preferably 150 to 300°C. At this time, if the drying temperature is less than 100°C, it is undesirable because evaporation of the dispersion medium is difficult, and if the drying temperature exceeds 350°C, it is undesirable because oxidation of the conductive material may occur. Therefore, it is preferable that the drying temperature is at least 100°C or higher and does not exceed 350°C.

Additionally, the drying process is preferably carried out at the above temperature for 10 minutes to 6 hours. This drying process dries the composition for supercapacitor electrodes (evaporates the dispersion medium) and at the same time binds the powder particles to improve the strength of the supercapacitor electrode.

As shown in FIG. 4, lead wires 130 and 140 are attached to the anode 120 and the cathode 110, respectively, which are manufactured by coating the cathode and anode compositions for a supercapacitor on a metal foil or forming a sheet and attaching the composition to the metal foil or current collector. ) is attached.

Next, as shown in FIG. 5, the first separator 150, the anode 120, the second separator 160, and the cathode 110 are stacked and coiled to form a roll. After manufacturing the winding element 175, the roll shape is maintained by wrapping an adhesive tape 170 around the roll.

The second separator 160 provided between the anode 120 and the cathode 110 serves to prevent short circuit between the anode 120 and the cathode 110. Each of the first and second separators 150 and 160 is not particularly limited as long as it is a separator commonly used in the battery field, such as polyolefin, polyethylene, or polypropylene.

Next, as shown in FIG. 6, a sealing rubber 180 is mounted on the resulting roll-shaped product and inserted into a metal cap (eg, aluminum case) 190.

The roll-shaped winding element 175 is impregnated, injected with an electrolyte solution, and sealed.

In this way, the manufactured supercapacitor is schematically shown in FIG. 7.

In the supercapacitor 100 manufactured as described above, the anode 120 and the cathode 110 are arranged to be spaced apart from each other, and the anode 120 and the cathode 110 are positioned between the anode 120 and the cathode 110. Separators 150 and 160 are disposed to prevent short circuits, and the anode 120 and cathode 110 are impregnated with an electrolyte solution.

Here, the electrolyte solution includes a non-aqueous electrolyte solution and 1 to 25 parts by weight of an ionic liquid based on 100 parts by weight of the non-aqueous electrolyte solution, and the non-aqueous electrolyte solution includes an organic solvent and lithium salt LiPF ₆ (lithium hexafluorophosphate) and LiBF ₄ (lithium tetrafluoroborate), LiClO ₄ (lithium perchlorate), LiFSI (lithium bis(fluorosulfonyl)imide), sodium salt NaPF ₆ (sodium hexafluorophosphate), NaDFOB (sodium difluoro(oxalate)borate) and potassium salt KFSI (potassium bis(fluorosulfonyl) imide) and KPF ₆ (potassium hexafluorophosphate). Organic solvents include acetonitrile, propylene carbonate, ethylene carbonate, ethylmethyl carbonate, dimethyl carbonate, diethyl carbonate, butylene carbonate, vinylene carbonate, tetrahydrofuran, 1,2-dioxane, 2 -It may contain one or more substances selected from the group consisting of methyltetrahydrofuran, butyrolactone, and dimethylformamide.

Ionic liquids include EMITf ₂ N (1-Ethyl-3-methylimidazolium trifluoromethanesulfonylamide), BMITf ₂ N (1-Butyl-3-methylimidazolium trifluoromethanesulfonylamide), EMITFSI (1-Ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide), and BMIMBF _4. (1-Butyl-3-methylimidazolium tetrafluoroborate), OMIMBF ₄ (1-Methyl-3-octylimidazolium tetrafluoroborate), OMIMTf ₂ N(1-Methyl-3-octylimidazolium trifluoromethanesulfonylamide), MEMPBF ₄ (N-(2-Methoxyethyl)-N -methylpyrrolidinium tetrafloroborate) and DEMEBF ₄ (N,N-Diethyl-N-methyl-N-(2-methoxyethyl)ammonium tetrafloroborate).

Example

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, this is presented as a preferred example of the present invention and should not be construed as limiting the present invention in any way.

Any information not described here can be technically inferred by anyone skilled in the art, so description thereof will be omitted.

1. Sample preparation

Example 1

Nitrogen-doped activated carbon manufacturing

A suspension was prepared by mixing the surface modifier, activated carbon, and solvent in a ratio of 0.01g:10g:1L. At this time, CTAB (Cetyl trimethyl ammonium bromide) was used as a surface modifier, coke-based activated carbon was used as activated carbon, and distilled water was used as a solvent.

Next, the suspension was stirred at a speed of 400 rpm using a magnetic stirrer at 10°C for 6 hours and dispersed using ultrasonication.

Next, the stirred suspension was filtered and dried in a convection oven for 12 hours to obtain surface-modified activated carbon.

Next, 1L of solvent was added to the reflux reactor and 0.5g of tetramethylethylenediamine, a nitrogen source, was dissolved.

Next, the mixed solution in which the nitrogen source is dissolved is heated to 120°C, then 100 g of surface-modified activated carbon is added to the heated mixed solution, stirred at a speed of 200 rpm for 12 hours, and water boiled at 120°C, and the water boiled mixture is completed. The solution was dried at 120°C.

Next, the dried mixture was placed in the reactor, the reactor was placed in a vertical furnace, and Ar gas was flowed at a flow rate of 500 cc/min to maintain an inert gas atmosphere, and the temperature was raised to 900°C at a temperature increase rate of 2°C/min. Nitrogen-doped activated carbon was prepared by heat treatment for 3 hours in this condition.

Supercapacitor manufacturing

0.8g of nitrogen-doped activated carbon, 0.1g of carbon black (super-p) as a conductive material, and 0.1g of PVDF as a binder were added to NMP as a dispersion medium and mixed for 20 minutes with a three-dimensional stirrer (Thinky mixer) to prepare a slurry, and then mixed with a doctor blade. An electrode composition for a supercapacitor was prepared using this method.

Next, the electrode composition for supercapacitors was rolled using a roll press under the conditions of pressurizing pressure of 10 ton/cm2 and roll temperature of 60℃ to form a sheet and attached to the current collector, then placed in a vacuum drying rack at 150℃ and dried for 12 hours. A 150㎛ thick supercapacitor electrode was manufactured.

Next, vacuum-dried supercapacitor electrodes were used as the cathode and anode, respectively, assembled into a 2032 coin cell, and then impregnated with an electrolyte to manufacture a hybrid supercapacitor. At this time, the separator used was TF4035, and the electrolyte was 1 M TEABF4/ACN, an electrolyte for supercapacitors.

Comparative Example 1

A supercapacitor was manufactured in the same manner as in Example 1, except that pure coke-based activated carbon without nitrogen doping was used as an electrode active material for the supercapacitor without surface modification, double boiling, or heat treatment.

Comparative Example 2

A supercapacitor was manufactured in the same manner as in Example 1, except that surface modification treatment was not performed, and coke-based nitrogen-doped activated carbon prepared in the same manner as in Example 1 was used as the electrode active material for the supercapacitor. .

2. XPS analysis

Table 1 shows the XPS analysis results for the electrode active materials prepared according to Example 1 and Comparative Examples 1 to 2.

[Table 1]

As shown in Table 1, as can be seen from the XPS analysis results, a large amount of nitrogen was detected in the nitrogen-doped activated carbon prepared according to Example 1.

On the other hand, nitrogen was not detected in the coke-based activated carbon according to Comparative Example 1.

In addition, it was confirmed that nitrogen was detected in the nitrogen-doped activated carbon prepared according to Comparative Example 2, but in a trace amount compared to Example 1.

Meanwhile, Figures 8 and 9 are graphs showing the strength according to binding energy of the supercapacitor electrodes manufactured according to Example 1 and Comparative Examples 1 and 2.

As shown in Figures 8 and 9, it was confirmed that the strength of the supercapacitor electrode manufactured according to Example 1 was significantly improved compared to the supercapacitor electrode manufactured according to Comparative Examples 1 and 2.

3. Electrochemical performance evaluation

Table 2 shows the electrical conductivity measurement results for the supercapacitors manufactured according to Example 1 and Comparative Examples 1 to 2. In addition, Figure 10 is a graph showing the results of measuring specific capacitance values for each current density of supercapacitors manufactured according to Example 1 and Comparative Examples 1 to 2.

At this time, a constant current charge was used to measure the specific storage capacity, ratio characteristics according to various current densities, leakage current, and voltage drop (IR-drop) during discharge of the supercapacitors manufactured according to Example 1 and Comparative Examples 1 and 2. A discharge method (Galvanostatic Charge/Discharge test) was performed. The equipment used for measurement was a Potentiostat (VSP, EC-Lab, France), with a voltage range of 0 to 2.7V at room temperature and a voltage of 0.5, 1, 2, 5, 10, 20, 30, 50 mA/ ^cm2 . Electrochemical performance was measured at various current densities.

[Table 2]

As shown in Table 2, as a result of comparing the electrical conductivity of the supercapacitors manufactured according to Example 1 and Comparative Examples 1 to 2, the overall electrical conductivity of Example 1 was improved compared to Comparative Examples 1 to 2. You can check that.

In addition, as shown in Figure 10, as can be seen from the results of measuring electrochemical performance at various current densities of 0.5, 1, 2, 5, 10, 20, 30, and 50 mA/cm ² , in Example 1 It can be seen that the specific capacitance value of the supercapacitor manufactured according to each current density was significantly higher than that of the supercapacitor manufactured according to Comparative Examples 1 and 2.

At this time, the supercapacitor manufactured according to Example 1 showed a capacity retention rate of more than 90% under a current density condition of 50 mA/cm ² . On the other hand, the supercapacitors manufactured according to Comparative Examples 1 and 2 showed a capacity retention rate of approximately 80% or less under a current density condition of 50 mA/cm ² .

Although the above description focuses on the embodiments of the present invention, various changes or modifications can be made at the level of a person skilled in the art in the technical field to which the present invention pertains. These changes and modifications can be said to belong to the present invention as long as they do not depart from the scope of the technical idea provided by the present invention. Therefore, the scope of rights of the present invention should be determined by the claims described below.

S10: Surface modification step
S20: double boiling stage
S30: heat treatment step

Claims (15)

(a) modifying the surface of the electrode active material using a surface modifier;
(b) reacting the surface-modified electrode active material with a nitrogen source and boiling the surface-modified electrode active material to attach the nitrogen source to the surface of the surface-modified electrode active material; and
(c) heat treating the electrode active material to which the nitrogen source is attached at 500 to 1,200°C to form a nitrogen-doped electrode active material,
In step (a), the surface modifier includes at least one selected from cetyl trimethyl ammonium bromide (CTAB) and ammonium lauryl sulfate (ALS). A method of manufacturing a nitrogen-doped electrode active material using a reduced amount of chemicals.
According to paragraph 1,
In step (a),
(a-1) mixing the surface modifier and electrode active material in a solvent to form a suspension;
(a-2) stirring the suspension at 5 to 15°C for 4 to 8 hours at a speed of 300 to 600 rpm; and
(a-3) filtering the stirred suspension and drying it for 5 to 25 hours to obtain a surface-modified electrode active material;
A method for producing a nitrogen-doped electrode active material with a reduced amount of chemicals using a surface modifier, comprising:
delete According to paragraph 1,
The surface modifier is
A method of producing a nitrogen-doped electrode active material with a reduced chemical amount using a surface modifier, characterized in that 0.1 to 10 parts by weight is added based on 100 parts by weight of the electrode active material.
According to paragraph 2,
In step (a-2) above,
A method of manufacturing a nitrogen-doped electrode active material with a reduced chemical amount using a surface modifier, characterized in that the stirring is performed simultaneously using ultrasonication.
According to paragraph 2,
The electrode active material is
A method of manufacturing a nitrogen-doped electrode active material with a reduced amount of chemicals using a surface modifier comprising at least one selected from graphene, carbon nanotubes, and activated carbon.
According to paragraph 1,
In step (b),
(b-1) dissolving the nitrogen element in a solvent;
(b-2) heating the mixed solution in which the nitrogen source is dissolved to 100 to 120°C; and
(b-3) adding the surface-modified electrode active material to the heated mixed solution, stirring it, and then bathing at 100 to 120°C;
A method for producing a nitrogen-doped electrode active material with a reduced amount of chemicals using a surface modifier, comprising:
In clause 7,
In step (b-1) above,
The nitrogen source is
Polyacrylonitrile, polyaniline, tetramethylethylenediamine, polypyrrole, polyrhodanine, melanin, urea, purine, Drug dosage using a surface modifier comprising at least one selected from adenine, guanine, hypoxanthine, xanthine, theobromine and caffeine. Method for producing a nitrogen-doped electrode active material with reduced .
In clause 7,
After step (b-3) above,
(b-4) drying the mixed solution after the double boiling at 100 to 120°C;
A method for producing a nitrogen-doped electrode active material with a reduced amount of chemicals using a surface modifier, further comprising:
According to paragraph 1,
In step (c) above,
The heat treatment is
A method of manufacturing a nitrogen-doped electrode active material with a reduced amount of chemicals using a surface modifier, which is carried out at 500 to 1,200°C for 1 to 10 hours in an inert gas atmosphere.
According to paragraph 1,
After step (c) above,
The nitrogen-doped electrode active material is
A method for producing a nitrogen-doped electrode active material in which the amount of chemical is reduced using a surface modifier, characterized in that the nitrogen is doped at 0.1 to 3.0 atomic% based on 100 atomic% of the total electrode active material.
A negative electrode containing a negative electrode active material, a conductive material, and a binder;
a positive electrode disposed spaced apart from the negative electrode and including a positive electrode active material, a conductive material, and a binder;
a separator disposed between the cathode and the anode to prevent short circuit between the cathode and the anode; and
It includes an electrolyte solution impregnated in the cathode and anode,
At least one of the negative electrode active material and the positive electrode active material is a nitrogen-doped supercapacitor electrode in which the amount of chemical is reduced using a surface modifier prepared according to any one of claims 1 to 2 and 4 to 11. Active materials are used,
The nitrogen-doped electrode active material is doped with 0.5 to 3.0 atomic% of nitrogen based on 100 atomic% of the total electrode active material,
The surface modifier is a surface modifier that contains at least one selected from cetyl trimethyl ammonium bromide (CTAB) and ammonium lauryl sulfate (ALS) to reduce the amount of chemicals. Supercapacitor using nitrogen-doped electrode active material.
According to clause 12,
The supercapacitor is
A supercapacitor using a nitrogen-doped electrode active material with a reduced chemical content using a surface modifier that exhibits a capacity retention rate of more than 90% under a current density of 50 mA/cm ² .
(a) preparing a composition for a supercapacitor electrode by mixing an electrode active material, a conductive material, and a binder in a dispersion medium;
(b) compressing the supercapacitor electrode composition to form an electrode, coating the supercapacitor electrode composition on a metal foil to form an electrode, or pressing the supercapacitor electrode composition with a roller to form a sheet. Forming an electrode by attaching it to a metal foil or current collector;
(c) drying the resulting electrode-shaped product to form a supercapacitor electrode; and
(d) using the supercapacitor electrode as an anode and a cathode, placing a separator between the anode and the cathode to prevent short circuit between the anode and the cathode, and impregnating it with an electrolyte solution;
In step (a), the electrode active material is used for a nitrogen-doped supercapacitor in which the amount of chemical is reduced using the surface modifier prepared according to any one of claims 1 to 2 and 4 to 11. Electrode active materials are used,
The nitrogen-doped electrode active material is doped with 0.5 to 3.0 atomic% of nitrogen based on 100 atomic% of the total electrode active material,
The surface modifier is a surface modifier that contains at least one selected from cetyl trimethyl ammonium bromide (CTAB) and ammonium lauryl sulfate (ALS) to reduce the amount of chemicals. Supercapacitor manufacturing method using nitrogen-doped electrode active material.
According to clause 14,
The supercapacitor is
A method of manufacturing a supercapacitor using a nitrogen-doped electrode active material in which the amount of chemicals is reduced using a surface modifier, characterized in that it exhibits a capacity retention rate of more than 90% under a current density of 50 mA/ ^cm 2.

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