WO2024025084A1 - Preparation method for carbon material dispersion solution by using multi-frequency dispersion and preparation method for positive electrode comprising carbon material dispersion solution - Google Patents

Preparation method for carbon material dispersion solution by using multi-frequency dispersion and preparation method for positive electrode comprising carbon material dispersion solution Download PDF

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WO2024025084A1
WO2024025084A1 PCT/KR2023/005680 KR2023005680W WO2024025084A1 WO 2024025084 A1 WO2024025084 A1 WO 2024025084A1 KR 2023005680 W KR2023005680 W KR 2023005680W WO 2024025084 A1 WO2024025084 A1 WO 2024025084A1
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carbon material
dispersion solution
frequency
material dispersion
positive electrode
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PCT/KR2023/005680
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French (fr)
Korean (ko)
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윤기로
송서원
이창호
신서윤
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한국생산기술연구원
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F31/00—Mixers with shaking, oscillating, or vibrating mechanisms
    • B01F31/80—Mixing by means of high-frequency vibrations above one kHz, e.g. ultrasonic vibrations
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a method for producing a carbon material dispersion solution using multi-frequency dispersion and a method for producing an anode containing the same.
  • the material (mixture) that makes up the electrode (anode or cathode) of a secondary battery is composed of an active material, a binder, and a conductive agent.
  • the conductive material promotes electron movement within the anode and cathode. Although only a small amount is used in electrodes, it is an additive material that plays a very important role in improving the performance of secondary batteries.
  • Carbon black is mainly used as a conductive material, but recently, various carbon materials such as conducting graphite or carbon nano tube (CNT) have been developed and attempted to be applied.
  • CNTs have graphite sheets rolled into a cylindrical shape with a nanometer-sized diameter, and their electrical conductivity is similar to that of copper.
  • the diameter of CNTs is only a few to tens of nanometers, and CNTs are classified into single-walled CNTs (Single-Walled Carbon Nanotubes, SWCNTs) or multi-walled CNTs (Multi-Walled Carbon Nanotubes, MWCNTs) depending on the number of partitions.
  • CNTs have the characteristic of an elongated one-dimensional (1D) structure, when used as a conductive material, they can form a flexible conductive network through line-to-point contact with the electrode active material, which is much better than point-to-point carbon black. Even with a small amount, active material particles can be connected more effectively.
  • using CNT conductive materials in anode materials increases energy capacity by providing more active sites, and CNTs with high electrical conductivity are known to improve the efficiency and output performance of secondary batteries.
  • the amount used can be reduced to 1/5 compared to carbon black, an existing conductive material, and the volumetric energy density of secondary batteries can be dramatically improved because more active materials can be injected into the same volume.
  • CNTs In general, various low-cost synthesis technologies have been developed for CNTs, but since agglomeration occurs during the synthesis stage and they are obtained in a fine powder state, they are difficult to use on their own.
  • CNTs In order for CNTs to exhibit properties such as conductivity, they must be physically dispersed in a solution. It must be prepared in the form of an intermediate material, such as by combining it with another material.
  • SWCNTs form bundles due to strong Van Der Waals forces, or in the case of MWCNTs, they form aggregates that are entangled with each other.
  • the object of the present invention is a method for producing a carbon material dispersion solution capable of uniformly dispersing carbon materials in sizes of nanometer or less while maintaining excellent physical properties by performing dispersion treatment using multiple frequencies (low frequency and high frequency), and including the same.
  • the aim is to provide a method for manufacturing an anode.
  • the present invention provides a method for manufacturing a carbon material dispersion solution that can be mass-produced by continuously performing dispersion treatment using multiple frequencies, and a method for manufacturing an anode containing the same.
  • the present invention provides a method for manufacturing a carbon material dispersion solution that can improve the efficiency and capacity of a battery by applying it to the secondary battery industry, and a method for manufacturing a positive electrode containing the same.
  • a) preparing a carbon material solution containing a carbon material (b) subjecting the carbon material solution to primary ultrasonic treatment to prepare a first carbon material dispersion solution containing the carbon material subjected to primary ultrasonic treatment; and (c) subjecting the primary carbon material dispersion solution to secondary ultrasonic treatment to prepare a second carbon material dispersion solution containing the secondary ultrasonic treated carbon material.
  • a manufacturing method is provided.
  • the first ultrasonic treatment may be a low-frequency treatment using low frequencies
  • the second ultrasonic treatment may be a high-frequency treatment using high frequencies
  • the low-frequency processing is performed at 10 to 45 kHz
  • the high-frequency processing is performed at 35 to 180 kHz
  • the frequency of the high frequency may be greater than the frequency of the low frequency.
  • the low-frequency processing may be performed at 10 to 35 kHz, and the high-frequency processing may be performed at 40 to 170 kHz.
  • the frequency difference between the high frequency and the low frequency may be 10 to 170 kHz.
  • the first ultrasonic treatment and the second ultrasonic treatment are composed of a nozzle-type, probe-type, prismatic bath-type, and cylindrical bath-type, respectively. It may be performed with one or more ultrasonic processors selected from the group.
  • the carbon material may include one or more selected from the group consisting of carbon nanotubes, carbon black, graphene, acetylene black, Denka black, graphite, and activated carbon.
  • the carbon material may include carbon nanotubes.
  • the carbon material solution may additionally include a solvent.
  • the solvent may include one or more selected from the group consisting of water, ethanol, isopropyl alcohol (IPA), dimethylformamide (DMF), and methylpyrrolidone (NMP).
  • IPA isopropyl alcohol
  • DMF dimethylformamide
  • NMP methylpyrrolidone
  • the average particle size of the secondary ultrasonic treated carbon material may be smaller than the average particle size of the carbon material.
  • preparing a carbon material dispersion solution by treating a carbon material solution containing the carbon material with low-frequency ultrasound and high-frequency ultrasound, respectively; (b) preparing a positive electrode slurry containing a positive electrode active material, the carbon material dispersion solution, and a binder; and (c) manufacturing a positive electrode by applying the positive electrode slurry on one or both sides of a current collector and drying it.
  • Step (a) includes (a-1) preparing a carbon material solution containing a carbon material; (a-2) preparing a carbon material dispersion solution containing the carbon material subjected to primary ultrasonic treatment by first ultrasonicating the carbon material solution with either the low frequency or the high frequency ultrasound; And (a-3) secondary ultrasonic treatment of the carbon material dispersion solution of step (a-2) with another one of the low frequency and the high frequency ultrasonic waves to prepare a carbon material dispersion solution containing the secondary ultrasonic treated carbon material. It may additionally include a step of doing so.
  • the positive electrode active material is lithium iron phosphate (LiFePO 4 ), lithium nickel cobalt aluminum oxide (NCA), lithium cobalt oxide (LiCoO 2 ), lithium nickel oxide (LiNiO 2 ), and lithium manganese oxide. (LiMn 2 O 4 ) and lithium nickel cobalt manganese oxide (NCM).
  • the binder is polyethylene oxide, nitrile butadiene rubber (NBR), polyethylene glycol, polyacrylonitrile, polyvinyl chloride, polymethylmethacrylate, Contains at least one selected from the group consisting of polypropyleneoxide, polydimethylsiloxane, polyvinylidenefluoride, polyvinylidenecarbonate, and polyvinyl pyrrolidinone. can do.
  • the positive electrode active material Based on 100 parts by weight of the positive electrode active material, 1 to 10 parts by weight of the carbon material dispersion solution; It may include 5 to 20 parts by weight of the binder.
  • a method for manufacturing a lithium secondary battery including the method for manufacturing the positive electrode is provided.
  • the lithium secondary battery may include a negative electrode, and the negative electrode may include lithium metal.
  • the lithium secondary battery may additionally include an electrolyte.
  • the electrolyte is ethylene carbonate (EC), ethylmethyl carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), acetonitrile (AC), and propylene carbonate ( propylene carbonate (PC), polyethylene glycol, butylene carbonate (BC), vinylene carbonate (VC), 1,3-propane sultone (PS), Fluoroethylene carbonate (FEC), tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran, butyrolactone, dimethylformamide, 1,2 dimethoxylethane (DME), and succinonitrile. (Succinonitrile, SC).
  • the method for producing a carbon material dispersion solution of the present invention and the method for producing an anode containing the same are performed by performing ultrasonic dispersion treatment using multiple frequencies (low frequency and high frequency), thereby maintaining excellent physical properties and uniformly dispersing the carbon material to a size of nanometer or less. It has the effect of dispersing it.
  • the present invention has the effect of enabling mass production by continuously performing dispersion processing using low and high frequencies.
  • the present invention can be applied and applied to the secondary battery industry, and has the effect of improving the efficiency and capacity of the battery.
  • Figure 1 is a flowchart of a method for producing a carbon material dispersion solution using multi-frequency dispersion according to the present invention.
  • Figure 2 is a schematic diagram of a method for producing a carbon material dispersion solution using multi-frequency dispersion and a method for producing an anode containing the same according to the present invention.
  • Figure 3 shows optical measurements for evaluating the dispersibility of solutions according to Comparative Example 2-1 (R-CNT), Example 1-1 (MF-CNT), and Example 1-1 (MF-CNT) after 3 weeks. It is an image.
  • Figure 4 is a scanning electron microscope (SEM) image of solutions according to Example 1-2 and Comparative Examples 1-2 and 2-2.
  • Figure 5 is a scanning electron microscope (SEM) image of the positive electrode composite according to Example 2 and Comparative Examples 3 and 4.
  • Figure 6 is a graph showing the particle size distribution of solutions according to Comparative Example 1-1, Comparative Example 2-1, and Example 1-1.
  • Figure 7 is a graph showing the particle size distribution of solutions according to Comparative Example 1-2, Comparative Example 2-2, and Example 1-2.
  • Figure 8 is a graph comparing the viscosity of solutions according to Comparative Example 1-1, Comparative Example 1-2, Comparative Example 2-1, Comparative Example 2-2, Example 1-1, and Example 1-2.
  • Figure 9 is a graph showing the charge and discharge characteristics of batteries according to Device Example 1 and Device Comparative Examples 1 and 2.
  • Figure 10 is a graph showing the rate change of the battery according to Device Example 1 and Device Comparative Examples 1 and 2.
  • Figure 11 is a graph showing the cycle characteristics of batteries according to Device Example 1 and Device Comparative Examples 1 and 2.
  • Figure 12 is a graph showing the volume resistivity of electrode compounds according to Example 2 and Comparative Examples 3 and 4.
  • Figure 13 is a graph showing the measured interface resistance between the electrode composite and the current collector according to Example 2 and Comparative Examples 3 and 4.
  • first, second, etc. which will be used below, may be used to describe various components, but the components are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.
  • a first component may be named a second component, and similarly, the second component may also be named a first component without departing from the scope of the present invention.
  • a component when referred to as being “on another component,” “formed on another component,” “located on another component,” or “stacked on another component,” It may be formed by being directly attached to the front or one side of the surface of another component, positioned, or stacked, but it should be understood that other components may further exist in the middle.
  • Figure 1 is a flowchart of a method for producing a carbon material dispersion solution using multi-frequency dispersion according to the present invention
  • Figure 2 is a method for producing a carbon material dispersion solution using multi-frequency dispersion according to the present invention and manufacturing an anode containing the same.
  • This is a schematic diagram of the method.
  • a method for producing a carbon material dispersion solution of the present invention and a method for producing a positive electrode containing the same will be described with reference to FIGS. 1 and 2.
  • the present invention includes the steps of (a) preparing a carbon material solution containing carbon material; (b) subjecting the carbon material solution to primary ultrasonic treatment to prepare a first carbon material dispersion solution containing the carbon material subjected to primary ultrasonic treatment; and (c) subjecting the primary carbon material dispersion solution to secondary ultrasonic treatment to prepare a second carbon material dispersion solution containing the secondary ultrasonic treated carbon material. Manufacturing method is provided.
  • the first ultrasonic treatment may be a low-frequency treatment using low frequencies
  • the second ultrasonic treatment may be a high-frequency treatment using high frequencies
  • the low-frequency processing is performed at 10 to 45 kHz
  • the high-frequency processing is performed at 35 to 180 kHz
  • the frequency of the high frequency may be greater than the frequency of the low frequency.
  • the low-frequency processing may be performed at 10 to 35 kHz
  • the high-frequency processing may be performed at 40 to 170 kHz. More preferably, the low-frequency processing may be performed at 10 to 25 kHz, and the high-frequency processing may be performed at 100 to 150 kHz.
  • the low-frequency treatment is performed at less than 10 kHz, the diameter of the cavitation pores created by ultrasonic waves is too large, so it is difficult to sufficiently penetrate the CNT aggregate, and the dispersion effect of the CNTs is poor, which is not desirable. If the low-frequency treatment is performed at more than 45 kHz, This is undesirable because the strength of cavitation is weak and the CNT aggregates cannot be sufficiently dispersed. In addition, if the high-frequency treatment is performed at less than 35 kHz, fine dispersion is difficult due to the large diameter of the cavitation pores, and the CNT bundle is difficult to disperse well, which is undesirable. If the high-frequency treatment is performed at more than 180 kHz, the intensity of cavitation is minimal, which is undesirable. not.
  • the frequency difference between the high frequency and the low frequency may be 10 to 170 kHz, preferably 30 to 150 kHz, and more preferably 50 to 120 kHz.
  • the first ultrasonic treatment and the second ultrasonic treatment are composed of a nozzle-type, probe-type, prismatic bath-type, and cylindrical bath-type, respectively. It may be performed with one or more ultrasonic processors selected from the group.
  • the carbon material may include one or more selected from the group consisting of carbon nanotubes, carbon black, graphene, acetylene black, Denka black, graphite, and activated carbon, and may preferably include carbon nanotubes.
  • the carbon material solution may additionally include a solvent.
  • the solvent may include one or more selected from the group consisting of water, ethanol, isopropyl alcohol (IPA), dimethylformamide (DMF), and methylpyrrolidone (NMP).
  • IPA isopropyl alcohol
  • DMF dimethylformamide
  • NMP methylpyrrolidone
  • the carbon material contained in the carbon material solution does not aggregate and can be uniformly dispersed.
  • the viscosity of the second carbon material dispersion solution may be higher than the viscosity of the carbon material solution.
  • the average particle size of the carbon material subjected to secondary ultrasonic treatment may be smaller than the average particle size of the carbon material.
  • the present invention includes the steps of (a) treating a carbon material solution containing carbon material with low-frequency ultrasound and high-frequency ultrasound, respectively, to prepare a carbon material dispersion solution; (b) preparing a positive electrode slurry containing a positive electrode active material, the carbon material dispersion solution, and a binder; and (c) manufacturing a positive electrode by applying the positive electrode slurry on one or both sides of a current collector and drying it.
  • Step (a) includes (a-1) preparing a carbon material solution containing a carbon material; (a-2) preparing a carbon material dispersion solution containing the carbon material subjected to primary ultrasonic treatment by first ultrasonicating the carbon material solution with either the low frequency or the high frequency ultrasound; And (a-3) secondary ultrasonic treatment of the carbon material dispersion solution of step (a-2) with another one of the low frequency and the high frequency ultrasonic waves to prepare a carbon material dispersion solution containing the secondary ultrasonic treated carbon material. It may additionally include a step of doing so.
  • the positive electrode active material is lithium iron phosphate (LiFePO 4 ), lithium nickel cobalt aluminum oxide (NCA), lithium cobalt oxide (LiCoO 2 ), lithium nickel oxide (LiNiO 2 ), and lithium manganese oxide. (LiMn 2 O 4 ) and lithium nickel cobalt manganese oxide (NCM), and preferably lithium nickel cobalt manganese oxide (NCM).
  • the binder is polyethylene oxide, nitrile butadiene rubber (NBR), polyethylene glycol, polyacrylonitrile, polyvinyl chloride, polymethylmethacrylate, Contains at least one selected from the group consisting of polypropyleneoxide, polydimethylsiloxane, polyvinylidenefluoride, polyvinylidenecarbonate, and polyvinyl pyrrolidinone. It may contain polyvinylidene fluoride.
  • the carbon material dispersion solution Based on 100 parts by weight of the positive electrode active material, 1 to 10 parts by weight of the carbon material dispersion solution; It may include 5 to 20 parts by weight of the binder, and preferably 2 to 6 parts by weight of the carbon material dispersion solution; It may include 8 to 15 parts by weight of the binder.
  • the present invention provides a method for manufacturing a lithium secondary battery including the method for manufacturing the positive electrode.
  • the lithium secondary battery may further include a negative electrode, and the negative electrode may include lithium metal.
  • the lithium secondary battery may additionally include an electrolyte.
  • the electrolyte is ethylene carbonate (EC), ethylmethyl carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), acetonitrile (AC), and propylene carbonate ( propylene carbonate (PC), polyethylene glycol, butylene carbonate (BC), vinylene carbonate (VC), 1,3-propane sultone (PS), Fluoroethylene carbonate (FEC), tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran, butyrolactone, dimethylformamide, 1,2 dimethoxylethane (DME), and succinonitrile. (Succinonitrile, SC).
  • Example 1-1 Preparation of multi-frequency treated carbon nanotube dispersion solution (MF-CNT)
  • a 1 wt% CNT solution was prepared by dissolving 2 g of carbon nanotubes (CNT) with an average length of 45 ⁇ m in 200 ml of water.
  • the 1 wt% CNT solution was dispersed through a nozzle or probe type low frequency (17 kHz) ultrasonic oscillator to prepare a low frequency treated CNT dispersion solution.
  • the low-frequency treated CNT dispersion solution was dispersed through a bath-type high frequency (120 kHz) ultrasonic oscillator to prepare a multi-frequency treated CNT dispersion solution.
  • Example 1-2 Preparation of multi-frequency treated carbon nanotube dispersion solution (MF-CNT)
  • a multi-frequency treated CNT dispersion solution was prepared in the same manner as Example 1-1, except that methylpyrrolidone (NMP, solvent) was used instead of water (solvent) in Example 1-1. .
  • NMC 811 was mixed as a positive electrode active material, the multi-frequency treated CNT dispersion solution according to Example 1-2 as a conductive material, and polyvinylidene fluoride (PVdF) as a binder.
  • NMC 811, the multi-frequency treated CNT dispersion solution according to Example 1-2 and the PVdF binder were weighed at the above weight ratio, and then a positive electrode slurry was prepared through a paste mixer.
  • the positive electrode slurry was applied to aluminum foil with a thickness of 20 ⁇ m using a doctor-blading casting method and dried to prepare a positive electrode with a composite loading of 12.8 mg/cm 2 .
  • a 2032 coin cell was manufactured using the positive electrode prepared according to Example 2 and the lithium foil as the negative electrode. At this time, a 16 ⁇ m thick porous polyethylene separator (porosity 45%) was used, and LiPF 6 electrolyte was added to a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC) in a volume ratio of 1:1. An electrolyte solution dissolved at a concentration of 1M was used.
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • a 1 wt% CNT solution was prepared by dissolving 2 g of carbon nanotubes (CNT) with an average length of 45 ⁇ m in 200 ml of water (solvent).
  • the 1 wt% CNT solution was dispersed through a nozzle or probe type low frequency (17 kHz) ultrasonic oscillator to prepare a low frequency treated CNT dispersion solution.
  • a low-frequency treated CNT dispersion solution was prepared in the same manner as Comparative Example 1-1, except that methylpyrrolidone (NMP, solvent) was used instead of water (solvent) in Comparative Example 1-1.
  • NMP methylpyrrolidone
  • a 1 wt% undispersed CNT solution was prepared by dissolving 2 g of carbon nanotubes (CNT) with an average length of 45 ⁇ m in 200 ml of water (solvent).
  • a CNT solution without dispersion treatment was prepared in the same manner as in Comparative Example 2-1, except that methylpyrrolidone (NMP, solvent) was used instead of water (solvent) in Comparative Example 2-1.
  • NMP methylpyrrolidone
  • Example 2 in the same manner as Example 2, except that instead of using the multi-frequency treated CNT dispersion solution according to Example 1-2, the low-frequency treated CNT dispersion solution according to Comparative Example 1-2 was used. An anode was manufactured.
  • Example 2 in the same manner as Example 2, except that instead of using the multi-frequency treated CNT dispersion solution according to Example 1-2, the undispersed CNT solution according to Comparative Example 2-2 was used. An anode was manufactured.
  • a battery was manufactured in the same manner as Device Example 1, except that the positive electrode according to Comparative Example 3 was used instead of the positive electrode manufactured according to Example 2 in Device Example 1.
  • a battery was manufactured in the same manner as Device Example 1, except that the positive electrode according to Comparative Example 4 was used instead of the positive electrode manufactured according to Example 2 in Device Example 1.
  • Figure 3 shows optical measurements for evaluating the dispersibility of solutions according to Comparative Example 2-1 (R-CNT), Example 1-1 (MF-CNT), and Example 1-1 (MF-CNT) after 3 weeks. It is an image.
  • Figure 4 is a scanning electron microscope (SEM) image of the solutions according to Example 1-2 and Comparative Examples 1-2 and 2-2
  • Figure 5 is a scanning electron microscope (SEM) image of the positive electrode composite according to Example 2 and Comparative Examples 3 and 4. This is a microscope (SEM) image.
  • the CNT bundles had an aggregated microstructure, and the diameter of the aggregates ranged from about 20 to 40 ⁇ m.
  • the agglomerates of CNT bundles had a fine structure in a pulverized shape
  • the CNT bundles had a fine structure in a well-dispersed shape. could be confirmed.
  • CNT bundle aggregates with a diameter of about 10 ⁇ m were confirmed in the positive electrode (Comparative Example 4) containing CNTs that were not dispersed, and it was found that the dispersion of CNTs and positive electrode active material particles was non-uniform.
  • CNT bundles in the range of about 2 ⁇ m or less were confirmed in the anode containing CNTs treated at low frequency (Comparative Example 3).
  • the positive electrode containing multi-frequency treated CNTs Example 2 had a microstructure in which the CNTs, positive electrode active material, and binder were well dispersed.
  • Figure 6 is a graph showing the particle size distribution of solutions according to Comparative Example 1-1, Comparative Example 2-1, and Example 1-1
  • Figure 7 is a graph showing Comparative Example 1-2, Comparative Example 2-2, and Example 1. This is a graph showing the particle size distribution of the solution according to -2, and the particle size distribution was measured using a particle size analysis device (Mastersizer 3000).
  • Figure 8 is a graph comparing the viscosity of solutions according to Comparative Example 1-1, Comparative Example 1-2, Comparative Example 2-1, Comparative Example 2-2, Example 1-1, and Example 1-2.
  • Figure 9 is a graph showing the charge and discharge characteristics of batteries according to Device Example 1 and Device Comparative Examples 1 and 2.
  • the coin-type batteries according to Device Example 1 and Device Comparative Examples 1 and 2 were each charged and discharged twice from 2.8 V to 4.2 V at 0.5 C to measure the initial charge and discharge capacity.
  • the initial discharge capacity of the battery according to Device Example 1 is 242.18 mAh/gNMC, which is higher than the initial charge and discharge capacity of 178.04 mAh/gNMC and 106.69 mAh/gNMC of the battery according to Device Comparative Examples 1 and 2. It can be confirmed that the discharge capacity has increased. In other words, it was confirmed that by using the multi-frequency treated CNT dispersion solution as a conductive material, the conductive material was ideally distributed in the pores between the positive electrode active material and the particles, thereby maximizing the utilization rate of the positive electrode active material. On the other hand, it can be seen that Device Comparative Examples 1 and 2 showed insufficient initial charge and discharge capacity because the conductive material was not uniformly mixed with the positive electrode active material.
  • Figure 10 is a graph showing the rate change of the battery according to Device Example 1 and Device Comparative Examples 1 and 2.
  • Coin-type batteries according to Device Example 1 and Device Comparative Examples 1 and 2 were changed from 3.0V to 4.2V by changing the current amount to 0.2 C, 0.5 C, 1 C, 2 C, 3 C, 5 C, and 0.2 C, respectively. -rate test was conducted.
  • Figure 11 is a graph showing the cycle characteristics of batteries according to Device Example 1 and Device Comparative Examples 1 and 2.
  • a charge/discharge life test was performed on the coin-type batteries according to Device Example 1 and Device Comparative Examples 1 and 2, respectively, within the range of 3.0V to 4.2V at 0.5 C.
  • each battery according to Device Example 1 and Device Comparative Examples 1 and 2 showed initial capacity maintenance rates of 89.82%, 95.57%, and 98.86% after 50 cycles, respectively.
  • the average discharge capacity of the battery according to Device Example 1 over 50 cycles is 227.5 mAh/gNMC, which is lower than the average discharge capacity of 178.6 mAh/gNMC and 127.3 mAh/gNMC over 50 cycles of the battery according to Device Comparative Examples 1 and 2. It was confirmed that the average discharge capacity was improved.
  • Figure 12 is a graph showing the volume resistivity of electrode mixtures according to Example 2, Comparative Example 3, and Comparative Example 4, and Figure 13 is a graph showing the electrode mixture and current collector according to Example 2, Comparative Example 3, and Comparative Example 4. This is a graph showing the measured interface resistance, and was measured using an electrode resistance measuring device (RM2610).
  • RM2610 electrode resistance measuring device
  • the measured value of 1.103 ⁇ cm which is the volume resistivity of the electrode mixture according to Example 2 is compared to the measured values of 1.303 ⁇ cm and 3.266 ⁇ cm, which are the volume resistivity of the electrode mixture according to Comparative Examples 3 and 4. It was confirmed that there was a decrease. In other words, in the case of multi-frequency treatment, a decrease in resistance due to the ideal distribution of the conductive material and an improvement in electrical conductivity could be expected.
  • the measured interfacial resistance of the electrode according to Example 2 is 0.471 ⁇ cm 2
  • the measured interfacial resistance of the electrode according to Comparative Examples 3 and 4 is 0.983 ⁇ cm 2 and 1.433 ⁇ cm 2

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Abstract

The present invention relates to a preparation method for a carbon material dispersion solution, comprising the steps of: (a) preparing a carbon material solution containing a carbon material; (b) preparing a first carbon material dispersion solution containing a first ultrasonicated carbon material by treating the carbon material solution with first ultrasonication; and (c) preparing a second carbon material dispersion solution containing a second ultrasonicated carbon material by treating the first carbon material dispersion solution with second ultrasonication. The preparation method for a carbon material dispersion solution and a preparation method for a positive electrode comprising the carbon material dispersion solution, according to the present invention, exhibit an effect of uniformly dispersing carbon material in a nanosize or smaller while maintaining excellent properties, by performing an ultrasonic-dispersion treatment using multi-frequency (low frequency and high frequency).

Description

다주파 분산을 이용한 탄소재 분산용액의 제조방법 및 그를 포함하는 양극의 제조방법Method for producing a carbon material dispersion solution using multi-frequency dispersion and a method for producing an anode containing the same
본 발명은 다주파 분산을 이용한 탄소재 분산용액의 제조방법 및 그를 포함하는 양극의 제조방법에 관한 것이다.The present invention relates to a method for producing a carbon material dispersion solution using multi-frequency dispersion and a method for producing an anode containing the same.
이차전지의 전극(양극 또는 음극)을 구성하는 재료(합제)는 활물질(Active Material)과 바인더(Binder), 도전재(Conductive Agent)로 구성되며, 도전재는 양극, 음극 내 전자 이동을 촉진시키는 역할로써 비록 전극에 소량만 사용되지만 이차전지의 성능을 향상시키는데 매우 중요한 역할을 하는 첨가소재이다.The material (mixture) that makes up the electrode (anode or cathode) of a secondary battery is composed of an active material, a binder, and a conductive agent. The conductive material promotes electron movement within the anode and cathode. Although only a small amount is used in electrodes, it is an additive material that plays a very important role in improving the performance of secondary batteries.
도전재로는 주로 카본블랙이 많이 사용되고 있으나, 최근 전도성 흑연(Conducting Graphite), 또는 탄소나노튜브(Carbon Nano Tube, CNT)와 같은 다양한 탄소 재료가 개발 및 적용 시도되고 있음. 그중 CNT 는 흑연면(Graphite sheet)이 나노미터 크기의 직경으로 둥글게 말려 원통형 모양을 이루고 있으며 전기전도도는 구리와 비슷하다. CNT의 직경은 수∼수십 나노미터에 불과하며, CNT 는 격벽 수에 따라 단일벽 CNT(Single-Walled Carbon Nanotube, SWCNT), 또는 다중벽CNT(Multi-Walled Carbon Nanotube, MWCNT)로 구분된다. Carbon black is mainly used as a conductive material, but recently, various carbon materials such as conducting graphite or carbon nano tube (CNT) have been developed and attempted to be applied. Among them, CNTs have graphite sheets rolled into a cylindrical shape with a nanometer-sized diameter, and their electrical conductivity is similar to that of copper. The diameter of CNTs is only a few to tens of nanometers, and CNTs are classified into single-walled CNTs (Single-Walled Carbon Nanotubes, SWCNTs) or multi-walled CNTs (Multi-Walled Carbon Nanotubes, MWCNTs) depending on the number of partitions.
이러한 CNT는 길게 뻗은 일차원(1D) 구조의 특징을 갖기 때문에 도전재로 사용시 전극 활물질과 Line-To-Point 컨택을 통해 유연한 전도성 네트워크를 형성 할 수 있어서 Point-To-Point 방식의 카본블랙에 비해 훨씬 적은 양으로도 활물질 입자를 더 효과적으로 연결시킬 수 있다. 또한 기존 카본블랙 기반 도전재 대비 CNT 도전재를 양극재에 사용하면 더 많은 활성 사이트를 제공해 에너지 용량을 높이고, 전기 전도도가 높은 CNT가 이차전지의 효율과 출력 성능을 향상시켜주는 것으로 알려져 있다. 특히, 기존 도전재인 카본블랙 대비 사용량을 1/5로 줄일 수 있으며, 동일 부피에 활물질을 더 많이 투입할 수 있기 때문에 이차전지의 체적 에너지 밀도(Volumetric Energy Density)를 비약적으로 향상시킬 수 있다.Because these CNTs have the characteristic of an elongated one-dimensional (1D) structure, when used as a conductive material, they can form a flexible conductive network through line-to-point contact with the electrode active material, which is much better than point-to-point carbon black. Even with a small amount, active material particles can be connected more effectively. In addition, compared to existing carbon black-based conductive materials, using CNT conductive materials in anode materials increases energy capacity by providing more active sites, and CNTs with high electrical conductivity are known to improve the efficiency and output performance of secondary batteries. In particular, the amount used can be reduced to 1/5 compared to carbon black, an existing conductive material, and the volumetric energy density of secondary batteries can be dramatically improved because more active materials can be injected into the same volume.
일반적으로 CNT는 다양한 저가 합성기술이 개발되었으나 합성단계에서 응집현상이 일어나며 미세분말 상태로 얻어지기 때문에 그 자체로는 사용되기 어려우며, CNT가 전도성 구현 등 특성들을 발현시키기 위해서는 반드시 용액에 물리적으로 분산시키거나 다른 소재와 복합화하는 등의 중간재 형태로 준비되어야 한다. 특히, 용액 내에서 SWCNT는 강한 반데르발스(Van Der Waals) 힘 때문에 번들을 형성하거나, MWCNT의 경우 서로 엉켜있는 모습의 응집체를 형성한다. CNT가 이차전지 전극용 도전재로서 요구되는 물성을 충분히 발휘하기 위해서는 합제를 제조하기 전 중간재 상태인 CNT 선분산액 제조 공정에서 가장 난제로 여겨지는 균일하고 안정적인 분산기술이 확보되어야 한다.In general, various low-cost synthesis technologies have been developed for CNTs, but since agglomeration occurs during the synthesis stage and they are obtained in a fine powder state, they are difficult to use on their own. In order for CNTs to exhibit properties such as conductivity, they must be physically dispersed in a solution. It must be prepared in the form of an intermediate material, such as by combining it with another material. In particular, in solution, SWCNTs form bundles due to strong Van Der Waals forces, or in the case of MWCNTs, they form aggregates that are entangled with each other. In order for CNTs to fully demonstrate the properties required as a conductive material for secondary battery electrodes, uniform and stable dispersion technology must be secured, which is considered the most difficult problem in the manufacturing process of CNT pre-dispersion, which is an intermediate material before manufacturing a mixture.
본 발명의 목적은 다주파(저주파 및 고주파)를 이용한 분산처리를 수행함으로써, 우수한 물성을 유지하면서, 탄소재를 나노 이하의 크기로 균일하게 분산시킬 수 있는 탄소재 분산용액의 제조방법 및 그를 포함하는 양극의 제조방법을 제공하는데 있다.The object of the present invention is a method for producing a carbon material dispersion solution capable of uniformly dispersing carbon materials in sizes of nanometer or less while maintaining excellent physical properties by performing dispersion treatment using multiple frequencies (low frequency and high frequency), and including the same. The aim is to provide a method for manufacturing an anode.
또한 본 발명은 다주파를 이용한 분산처리를 연속적으로 수행함으로써, 대량생산이 가능한 탄소재 분산용액의 제조방법 및 그를 포함하는 양극의 제조방법을 제공하는데 있다.In addition, the present invention provides a method for manufacturing a carbon material dispersion solution that can be mass-produced by continuously performing dispersion treatment using multiple frequencies, and a method for manufacturing an anode containing the same.
또한 본 발명은 이차전지 산업분야에 응용 및 적용함으로써, 전지의 효율 및 용량을 향상시킬 수 있는 탄소재 분산용액의 제조방법 및 그를 포함하는 양극의 제조방법을 제공하는데 있다.In addition, the present invention provides a method for manufacturing a carbon material dispersion solution that can improve the efficiency and capacity of a battery by applying it to the secondary battery industry, and a method for manufacturing a positive electrode containing the same.
본 발명의 일 측면에 따르면, (a) 탄소재를 포함하는 탄소재 용액을 제조하는 단계; (b) 상기 탄소재 용액을 1차 초음파 처리하여 1차 초음파 처리된 탄소재를 포함하는 제1 탄소재 분산용액을 제조하는 단계; 및 (c) 상기 1차 탄소재 분산용액을 2차 초음파 처리하여 2차 초음파 처리된 탄소재를 포함하는 제2 탄소재 분산용액을 제조하는 단계;를 포함하는 것을 특징으로 하는 탄소재 분산용액의 제조방법이 제공된다.According to one aspect of the present invention, (a) preparing a carbon material solution containing a carbon material; (b) subjecting the carbon material solution to primary ultrasonic treatment to prepare a first carbon material dispersion solution containing the carbon material subjected to primary ultrasonic treatment; and (c) subjecting the primary carbon material dispersion solution to secondary ultrasonic treatment to prepare a second carbon material dispersion solution containing the secondary ultrasonic treated carbon material. A manufacturing method is provided.
상기 1차 초음파 처리는 저주파를 사용하는 저주파 처리이고, 상기 2차 초음파 처리는 고주파를 사용하는 고주파 처리일 수 있다.The first ultrasonic treatment may be a low-frequency treatment using low frequencies, and the second ultrasonic treatment may be a high-frequency treatment using high frequencies.
상기 저주파 처리가 10 내지 45 kHz에서 수행되고, 상기 고주파 처리가 35 내지 180 kHz에서 수행되고, 상기 고주파의 주파수가 상기 저주파의 주파수보다 클 수 있다.The low-frequency processing is performed at 10 to 45 kHz, the high-frequency processing is performed at 35 to 180 kHz, and the frequency of the high frequency may be greater than the frequency of the low frequency.
상기 저주파 처리가 10 내지 35 kHz에서 수행되고, 상기 고주파 처리가 40 내지 170 kHz에서 수행될 수 있다.The low-frequency processing may be performed at 10 to 35 kHz, and the high-frequency processing may be performed at 40 to 170 kHz.
상기 고주파와 저주파의 주파수 차이가 10 내지 170 kHz일 수 있다.The frequency difference between the high frequency and the low frequency may be 10 to 170 kHz.
상기 1차 초음파 처리 및 상기 2차 초음파 처리는 각각 노즐 타입(Nozzle-Type), 프로브 타입(Probe-Type), 각형의 수조 타입(Bath-Type) 및 원통형의 수조 타입(Bath-Type)으로 이루어진 군으로부터 선택된 1종 이상의 초음파 처리기로 수행될 수 있다.The first ultrasonic treatment and the second ultrasonic treatment are composed of a nozzle-type, probe-type, prismatic bath-type, and cylindrical bath-type, respectively. It may be performed with one or more ultrasonic processors selected from the group.
상기 탄소재가 탄소나노튜브, 카본블랙, 그래핀, 아세틸렌 블랙, 덴카 블랙, 흑연 및 활성탄으로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.The carbon material may include one or more selected from the group consisting of carbon nanotubes, carbon black, graphene, acetylene black, Denka black, graphite, and activated carbon.
상기 탄소재가 탄소나노튜브를 포함할 수 있다.The carbon material may include carbon nanotubes.
상기 탄소재 용액이 용매를 추가로 포함할 수 있다.The carbon material solution may additionally include a solvent.
상기 용매가 물, 에탄올, 이소프로필알코올(IPA), 디메틸포름아미드(DMF) 및 메틸피롤리돈(NMP)으로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.The solvent may include one or more selected from the group consisting of water, ethanol, isopropyl alcohol (IPA), dimethylformamide (DMF), and methylpyrrolidone (NMP).
상기 2차 초음파 처리된 탄소재의 평균입도가 상기 탄소재의 평균입도보다 작을 수 있다.The average particle size of the secondary ultrasonic treated carbon material may be smaller than the average particle size of the carbon material.
본 발명의 일 측면에 따르면, (a) 탄소재를 포함하는 탄소재 용액을 저주파의 초음파 및 고주파의 초음파로 각각 처리하여 탄소재 분산용액을 제조하는 단계; (b) 양극 활물질, 상기 탄소재 분산용액 및 바인더를 포함하는 양극 슬러리를 제조하는 단계; 및 (c) 상기 양극 슬러리를 집전체의 일면 또는 양면 상에 도포하고 건조하여 양극을 제조하는 단계;를 포함하는 양극의 제조방법이 제공된다.According to one aspect of the present invention, (a) preparing a carbon material dispersion solution by treating a carbon material solution containing the carbon material with low-frequency ultrasound and high-frequency ultrasound, respectively; (b) preparing a positive electrode slurry containing a positive electrode active material, the carbon material dispersion solution, and a binder; and (c) manufacturing a positive electrode by applying the positive electrode slurry on one or both sides of a current collector and drying it.
단계 (a)가, (a-1) 탄소재를 포함하는 탄소재 용액을 제조하는 단계; (a-2) 상기 탄소재 용액을 상기 저주파 및 상기 고주파의 초음파 중 어느 하나로 1차 초음파 처리하여 1차 초음파 처리된 탄소재를 포함하는 탄소재 분산용액을 제조하는 단계; 및 (a-3) 단계 (a-2)의 상기 탄소재 분산용액을 상기 저주파 및 상기 고주파의 초음파 중 다른 하나로 2차 초음파 처리하여 2차 초음파 처리된 탄소재를 포함하는 탄소재 분산용액을 제조하는 단계;를 추가로 포함할 수 있다.Step (a) includes (a-1) preparing a carbon material solution containing a carbon material; (a-2) preparing a carbon material dispersion solution containing the carbon material subjected to primary ultrasonic treatment by first ultrasonicating the carbon material solution with either the low frequency or the high frequency ultrasound; And (a-3) secondary ultrasonic treatment of the carbon material dispersion solution of step (a-2) with another one of the low frequency and the high frequency ultrasonic waves to prepare a carbon material dispersion solution containing the secondary ultrasonic treated carbon material. It may additionally include a step of doing so.
상기 양극 활물질이 리튬철인산염계 산화물(lithium iron phosphate, LiFePO4), 리튬니켈코발트알루미늄계 산화물(NCA), 리튬코발트계 산화물(LiCoO2), 리튬니켈계 산화물(LiNiO2), 리튬망간계 산화물(LiMn2O4) 및 리튬니켈코발트망간계 산화물(NCM)로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.The positive electrode active material is lithium iron phosphate (LiFePO 4 ), lithium nickel cobalt aluminum oxide (NCA), lithium cobalt oxide (LiCoO 2 ), lithium nickel oxide (LiNiO 2 ), and lithium manganese oxide. (LiMn 2 O 4 ) and lithium nickel cobalt manganese oxide (NCM).
상기 바인더가 폴리에틸렌옥사이드(polyethyleneoxide), 니트릴부타디엔러버(NBR, nitrile butadiene rubber), 폴리에틸렌글리콜(polyethyleneglycol), 폴리아크릴로니트릴(polyacrylonitrile), 폴리비닐클로라이드(polyvinylchloride), 폴리메틸메타크릴레이트(polymethylmethacrylate), 폴리프로필렌옥사이드(polypropyleneoxide), 폴리디메틸실록산(polydimethylsiloxane), 폴리비닐리덴플루오라이드(polyvinylidenefluoride), 폴리비닐리덴카보네이트(polyvinylidenecarbonate) 및 폴리비닐피롤리디논(polyvinyl pyrrolidinone)으로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.The binder is polyethylene oxide, nitrile butadiene rubber (NBR), polyethylene glycol, polyacrylonitrile, polyvinyl chloride, polymethylmethacrylate, Contains at least one selected from the group consisting of polypropyleneoxide, polydimethylsiloxane, polyvinylidenefluoride, polyvinylidenecarbonate, and polyvinyl pyrrolidinone. can do.
상기 양극 활물질 100 중량부에 대하여, 상기 탄소재 분산용액 1 내지 10 중량부; 상기 바인더 5 내지 20 중량부;를 포함할 수 있다.Based on 100 parts by weight of the positive electrode active material, 1 to 10 parts by weight of the carbon material dispersion solution; It may include 5 to 20 parts by weight of the binder.
본 발명의 다른 일 측면에 따르면, 상기 양극의 제조방법을 포함하는 리튬이차전지의 제조방법이 제공된다.According to another aspect of the present invention, a method for manufacturing a lithium secondary battery including the method for manufacturing the positive electrode is provided.
상기 리튬이차전지가 음극을 포함하고, 상기 음극이 리튬 금속을 포함할 수 있다.The lithium secondary battery may include a negative electrode, and the negative electrode may include lithium metal.
상기 리튬이차전지가 전해질을 추가로 포함할 수 있다.The lithium secondary battery may additionally include an electrolyte.
상기 전해질이 에틸렌 카보네이트(ethylene carbonate, EC), 에틸메틸 카보네이트(ethylmethyl carbonate), 디메틸 카보네이트(dimethyl carbonate, DMC), 디에틸 카보네이트(diethyl carbonate, DEC), 아세토니트릴(acetonitrile, AC), 프로필렌 카보네이트(propylene carbonate, PC), 폴리에틸렌글리콜(polyehthylene glycol), 부틸렌 카보네이트(butylene carbonate, BC), 비닐렌 카보네이트(Vinylene carbonate, VC), 1,3-프로판설톤(1,3-propane sultone, PS), 플루오로에틸렌 카보네이트(fluoroethylene carbonate, FEC), 테트라히드로푸란, 1,2-디옥산, 2-메틸테트라히드로푸란, 부티로락톤, 디메틸포름아미드, 1,2 디메톡실에탄(DME) 및 석시노니트릴(Succinonitrile, SC)로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.The electrolyte is ethylene carbonate (EC), ethylmethyl carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), acetonitrile (AC), and propylene carbonate ( propylene carbonate (PC), polyethylene glycol, butylene carbonate (BC), vinylene carbonate (VC), 1,3-propane sultone (PS), Fluoroethylene carbonate (FEC), tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran, butyrolactone, dimethylformamide, 1,2 dimethoxylethane (DME), and succinonitrile. (Succinonitrile, SC).
본 발명의 탄소재 분산용액의 제조방법 및 그를 포함하는 양극의 제조방법은 다주파(저주파 및 고주파)를 이용한 초음파 분산처리를 수행함으로써, 우수한 물성을 유지하면서, 탄소재를 나노 이하의 크기로 균일하게 분산시킬 수 있는 효과가 있다.The method for producing a carbon material dispersion solution of the present invention and the method for producing an anode containing the same are performed by performing ultrasonic dispersion treatment using multiple frequencies (low frequency and high frequency), thereby maintaining excellent physical properties and uniformly dispersing the carbon material to a size of nanometer or less. It has the effect of dispersing it.
또한 본 발명은 저주파 및 고주파를 이용한 분산처리를 연속적으로 수행함으로써, 대량생산이 가능한 효과가 있다.In addition, the present invention has the effect of enabling mass production by continuously performing dispersion processing using low and high frequencies.
또한 본 발명은 이차전지 산업분야에 응용 및 적용할 수 있으며, 전지의 효율 및 용량이 향상되는 효과가 있다.In addition, the present invention can be applied and applied to the secondary battery industry, and has the effect of improving the efficiency and capacity of the battery.
도 1은 본 발명에 따른 다주파 분산을 이용한 탄소재 분산용액의 제조방법에 관한 순서도이다.Figure 1 is a flowchart of a method for producing a carbon material dispersion solution using multi-frequency dispersion according to the present invention.
도 2는 본 발명에 따른 다주파 분산을 이용한 탄소재 분산용액의 제조방법 및 그를 포함하는 양극의 제조방법에 관한 모식도이다.Figure 2 is a schematic diagram of a method for producing a carbon material dispersion solution using multi-frequency dispersion and a method for producing an anode containing the same according to the present invention.
도 3은 비교예 2-1(R-CNT), 실시예 1-1(MF-CNT) 및 3주 경과후 실시예 1-1(MF-CNT)에 따른 용액의 분산성을 평가하기 위한 광학이미지이다. Figure 3 shows optical measurements for evaluating the dispersibility of solutions according to Comparative Example 2-1 (R-CNT), Example 1-1 (MF-CNT), and Example 1-1 (MF-CNT) after 3 weeks. It is an image.
도 4는 실시예 1-2, 비교예 1-2 및 2-2에 따른 용액의 주사전자현미경(SEM) 이미지이다. Figure 4 is a scanning electron microscope (SEM) image of solutions according to Example 1-2 and Comparative Examples 1-2 and 2-2.
도 5는 실시예 2, 비교예 3 및 4에 따른 양극 합재의 주사전자현미경(SEM) 이미지이다.Figure 5 is a scanning electron microscope (SEM) image of the positive electrode composite according to Example 2 and Comparative Examples 3 and 4.
도 6은 비교예 1-1, 비교예 2-1 및 실시예 1-1에 따른 용액의 입자 크기 분포를 나타낸 그래프이다.Figure 6 is a graph showing the particle size distribution of solutions according to Comparative Example 1-1, Comparative Example 2-1, and Example 1-1.
도 7은 비교예 1-2, 비교예 2-2 및 실시예 1-2에 따른 용액의 입자 크기 분포를 나타낸 그래프이다.Figure 7 is a graph showing the particle size distribution of solutions according to Comparative Example 1-2, Comparative Example 2-2, and Example 1-2.
도 8은 비교예 1-1, 비교예 1-2, 비교예 2-1, 비교예 2-2, 실시예 1-1 및 실시예 1-2에 따른 용액의 점도를 비교한 그래프이다.Figure 8 is a graph comparing the viscosity of solutions according to Comparative Example 1-1, Comparative Example 1-2, Comparative Example 2-1, Comparative Example 2-2, Example 1-1, and Example 1-2.
도 9는 소자실시예 1, 소자비교예 1 및 2에 따른 전지의 충방전 특성을 나타낸 그래프이다.Figure 9 is a graph showing the charge and discharge characteristics of batteries according to Device Example 1 and Device Comparative Examples 1 and 2.
도 10은 소자실시예 1, 소자비교예 1 및 2에 따른 전지의 율속 변화를 나타낸 그래프이다. Figure 10 is a graph showing the rate change of the battery according to Device Example 1 and Device Comparative Examples 1 and 2.
도 11은 소자실시예 1, 소자비교예 1 및 2에 따른 전지의 싸이클 특성을 나타낸 그래프이다.Figure 11 is a graph showing the cycle characteristics of batteries according to Device Example 1 and Device Comparative Examples 1 and 2.
도 12는 실시예 2, 비교예 3 및 4에 따른 전극 합재의 체적 저항률을 측정하여 나타낸 그래프이다. Figure 12 is a graph showing the volume resistivity of electrode compounds according to Example 2 and Comparative Examples 3 and 4.
도 13은 실시예 2, 비교예 3 및 4에 따른 전극의 합재와 집전체의 계면 저항을 측정하여 나타낸 그래프이다.Figure 13 is a graph showing the measured interface resistance between the electrode composite and the current collector according to Example 2 and Comparative Examples 3 and 4.
본 발명은 다양한 변환을 가할 수 있고 여러 가지 실시예를 가질 수 있는 바, 특정 실시예들을 예시하고 상세한 설명에 상세하게 설명하고자 한다. 그러나, 이는 본 발명을 특정한 실시 형태에 대해 한정하려는 것이 아니며, 본 발명의 사상 및 기술 범위에 포함되는 모든 변환, 균등물 내지 대체물을 포함하는 것으로 이해되어야 한다. 본 발명을 설명함에 있어서 관련된 공지 기술에 대한 구체적인 설명이 본 발명의 요지를 흐릴 수 있다고 판단되는 경우 그 상세한 설명을 생략한다.Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be illustrated and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all transformations, equivalents, and substitutes included in the spirit and technical scope of the present invention. In describing the present invention, if it is determined that a detailed description of related known technologies may obscure the gist of the present invention, the detailed description will be omitted.
또한, 이하에서 사용될 제1, 제2 등과 같이 서수를 포함하는 용어는 다양한 구성요소들을 설명하는데 사용될 수 있지만, 상기 구성요소들은 상기 용어들에 의해 한정되지는 않는다. 상기 용어들은 하나의 구성요소를 다른 구성요소로부터 구별하는 목적으로만 사용된다. 예를 들어, 본 발명의 권리 범위를 벗어나지 않으면서 제1 구성요소는 제2 구성요소로 명명될 수 있고, 유사하게 제2 구성요소도 제1 구성요소로 명명될 수 있다. Additionally, terms including ordinal numbers, such as first, second, etc., which will be used below, may be used to describe various components, but the components are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, a first component may be named a second component, and similarly, the second component may also be named a first component without departing from the scope of the present invention.
또한, 어떤 구성요소가 “다른 구성요소 상에,” "다른 구성요소 상에 형성되어," "다른 구성요소 상에 위치하여," 또는 " 다른 구성요소 상에 적층되어" 있다고 언급된 때에는, 그 다른 구성요소의 표면 상의 전면 또는 일면에 직접 부착되어 형성되어, 위치하여 있거나 또는 적층되어 있을 수도 있지만, 중간에 다른 구성요소가 더 존재할 수도 있다고 이해되어야 할 것이다.Additionally, when a component is referred to as being “on another component,” “formed on another component,” “located on another component,” or “stacked on another component,” It may be formed by being directly attached to the front or one side of the surface of another component, positioned, or stacked, but it should be understood that other components may further exist in the middle.
단수의 표현은 문맥상 명백하게 다르게 뜻하지 않는 한, 복수의 표현을 포함한다. 본 출원에서, "포함하다" 또는 "가지다" 등의 용어는 명세서상에 기재된 특징, 숫자, 단계, 동작, 구성요소, 부품 또는 이들을 조합한 것이 존재함을 지정하려는 것이지, 하나 또는 그 이상의 다른 특징들이나 숫자, 단계, 동작, 구성요소, 부품 또는 이들을 조합한 것들의 존재 또는 부가 가능성을 미리 배제하지 않는 것으로 이해되어야 한다.Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.
도 1은 본 발명에 따른 다주파 분산을 이용한 탄소재 분산용액의 제조방법에 관한 순서도이고, 도 2는 본 발명에 따른 다주파 분산을 이용한 탄소재 분산용액의 제조방법 및 그를 포함하는 양극의 제조방법에 관한 모식도이다. 이하, 도 1 및 2를 참조하여 본 발명의 탄소재 분산용액의 제조방법 및 그를 포함하는 양극의 제조방법에 대해 설명하도록 한다. Figure 1 is a flowchart of a method for producing a carbon material dispersion solution using multi-frequency dispersion according to the present invention, and Figure 2 is a method for producing a carbon material dispersion solution using multi-frequency dispersion according to the present invention and manufacturing an anode containing the same. This is a schematic diagram of the method. Hereinafter, a method for producing a carbon material dispersion solution of the present invention and a method for producing a positive electrode containing the same will be described with reference to FIGS. 1 and 2.
본 발명은 (a) 탄소재를 포함하는 탄소재 용액을 제조하는 단계; (b) 상기 탄소재 용액을 1차 초음파 처리하여 1차 초음파 처리된 탄소재를 포함하는 제1 탄소재 분산용액을 제조하는 단계; 및 (c) 상기 1차 탄소재 분산용액을 2차 초음파 처리하여 2차 초음파 처리된 탄소재를 포함하는 제2 탄소재 분산용액을 제조하는 단계;를 포함하는 것을 특징으로 하는 탄소재 분산용액의 제조방법을 제공한다.The present invention includes the steps of (a) preparing a carbon material solution containing carbon material; (b) subjecting the carbon material solution to primary ultrasonic treatment to prepare a first carbon material dispersion solution containing the carbon material subjected to primary ultrasonic treatment; and (c) subjecting the primary carbon material dispersion solution to secondary ultrasonic treatment to prepare a second carbon material dispersion solution containing the secondary ultrasonic treated carbon material. Manufacturing method is provided.
상기 1차 초음파 처리는 저주파를 사용하는 저주파 처리이고, 상기 2차 초음파 처리는 고주파를 사용하는 고주파 처리일 수 있다.The first ultrasonic treatment may be a low-frequency treatment using low frequencies, and the second ultrasonic treatment may be a high-frequency treatment using high frequencies.
상기 저주파 처리가 10 내지 45 kHz에서 수행되고, 상기 고주파 처리가 35 내지 180 kHz에서 수행되고, 상기 고주파의 주파수가 상기 저주파의 주파수보다 클 수 있다. 바람직하게는 상기 저주파 처리가 10 내지 35 kHz에서 수행되고, 상기 고주파 처리가 40 내지 170 kHz에서 수행될 수 있다. 더욱 바람직하게는 상기 저주파 처리가 10 내지 25 kHz에서 수행되고, 상기 고주파 처리가 100 내지 150 kHz에서 수행될 수 있다. The low-frequency processing is performed at 10 to 45 kHz, the high-frequency processing is performed at 35 to 180 kHz, and the frequency of the high frequency may be greater than the frequency of the low frequency. Preferably, the low-frequency processing may be performed at 10 to 35 kHz, and the high-frequency processing may be performed at 40 to 170 kHz. More preferably, the low-frequency processing may be performed at 10 to 25 kHz, and the high-frequency processing may be performed at 100 to 150 kHz.
상기 저주파 처리가 10 kHz 미만으로 처리되면 초음파로 인해 생성되는 캐비테이션(Cavitaion) 기공의 직경이 너무 크기 때문에, CNT응집체에 충분히 침투하기 어려워서 CNT의 분산효과가 좋지 않아 바람직하지 않고, 45kHz 초과하여 처리되면 캐비테이션의 강도가 약해 CNT응집체를 충분히 분산 시킬 수 없어 바람직하지 않다. 또한 상기 고주파 처리가 35 kHz 미만으로 처리되면 캐비테이션의 기공의 직경이 크기 때문에 섬세한 분산이 어려워, CNT번들이 잘 분산되기에 투박하여 바람직하지 않고, 180 kHz 초과하여 처리되면 캐비테이션의 강도가 미미하여 바람직하지 않다. If the low-frequency treatment is performed at less than 10 kHz, the diameter of the cavitation pores created by ultrasonic waves is too large, so it is difficult to sufficiently penetrate the CNT aggregate, and the dispersion effect of the CNTs is poor, which is not desirable. If the low-frequency treatment is performed at more than 45 kHz, This is undesirable because the strength of cavitation is weak and the CNT aggregates cannot be sufficiently dispersed. In addition, if the high-frequency treatment is performed at less than 35 kHz, fine dispersion is difficult due to the large diameter of the cavitation pores, and the CNT bundle is difficult to disperse well, which is undesirable. If the high-frequency treatment is performed at more than 180 kHz, the intensity of cavitation is minimal, which is undesirable. not.
상기 고주파와 저주파의 주파수 차이가 10 내지 170 kHz일 수 있고, 바람직하게는 30 내지 150kHz, 더욱 바람직하게는 50 내지 120kHz일 수 있다.The frequency difference between the high frequency and the low frequency may be 10 to 170 kHz, preferably 30 to 150 kHz, and more preferably 50 to 120 kHz.
상기 1차 초음파 처리 및 상기 2차 초음파 처리는 각각 노즐 타입(Nozzle-Type), 프로브 타입(Probe-Type), 각형의 수조 타입(Bath-Type) 및 원통형의 수조 타입(Bath-Type)으로 이루어진 군으로부터 선택된 1종 이상의 초음파 처리기로 수행될 수 있다. The first ultrasonic treatment and the second ultrasonic treatment are composed of a nozzle-type, probe-type, prismatic bath-type, and cylindrical bath-type, respectively. It may be performed with one or more ultrasonic processors selected from the group.
상기 탄소재가 탄소나노튜브, 카본블랙, 그래핀, 아세틸렌 블랙, 덴카 블랙, 흑연 및 활성탄으로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있고, 바람직하게는 탄소나노튜브를 포함할 수 있다.The carbon material may include one or more selected from the group consisting of carbon nanotubes, carbon black, graphene, acetylene black, Denka black, graphite, and activated carbon, and may preferably include carbon nanotubes.
상기 탄소재 용액이 용매를 추가로 포함할 수 있다.The carbon material solution may additionally include a solvent.
상기 용매가 물, 에탄올, 이소프로필알코올(IPA), 디메틸포름아미드(DMF) 및 메틸피롤리돈(NMP)으로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.The solvent may include one or more selected from the group consisting of water, ethanol, isopropyl alcohol (IPA), dimethylformamide (DMF), and methylpyrrolidone (NMP).
상기 탄소재 용액을 상기 1차 초음파 처리 및 상기 2차 초음파 처리함으로써, 상기 탄소재 용액에 포함된 상기 탄소재가 응집하지 않고, 균일하게 분산될 수 있다.By subjecting the carbon material solution to the first ultrasonic treatment and the second ultrasonic treatment, the carbon material contained in the carbon material solution does not aggregate and can be uniformly dispersed.
상기 제2 탄소재 분산용액의 점도가 상기 탄소재 용액의 점도보다 높을 수 있다.The viscosity of the second carbon material dispersion solution may be higher than the viscosity of the carbon material solution.
상기 2차 초음파 처리된 탄소재의 평균입도가 상기 탄소재의 평균입도보다 작을 수 있다.The average particle size of the carbon material subjected to secondary ultrasonic treatment may be smaller than the average particle size of the carbon material.
또한 본 발명은 (a) 탄소재를 포함하는 탄소재 용액을 저주파의 초음파 및 고주파의 초음파로 각각 처리하여 탄소재 분산용액을 제조하는 단계; (b) 양극 활물질, 상기 탄소재 분산용액, 바인더를 포함하는 양극 슬러리를 제조하는 단계; 및 (c) 상기 양극 슬러리를 집전체의 일면 또는 양면 상에 도포하고 건조하여 양극을 제조하는 단계;를 포함하는 양극의 제조방법을 제공한다.In addition, the present invention includes the steps of (a) treating a carbon material solution containing carbon material with low-frequency ultrasound and high-frequency ultrasound, respectively, to prepare a carbon material dispersion solution; (b) preparing a positive electrode slurry containing a positive electrode active material, the carbon material dispersion solution, and a binder; and (c) manufacturing a positive electrode by applying the positive electrode slurry on one or both sides of a current collector and drying it.
단계 (a)가, (a-1) 탄소재를 포함하는 탄소재 용액을 제조하는 단계; (a-2) 상기 탄소재 용액을 상기 저주파 및 상기 고주파의 초음파 중 어느 하나로 1차 초음파 처리하여 1차 초음파 처리된 탄소재를 포함하는 탄소재 분산용액을 제조하는 단계; 및 (a-3) 단계 (a-2)의 상기 탄소재 분산용액을 상기 저주파 및 상기 고주파의 초음파 중 다른 하나로 2차 초음파 처리하여 2차 초음파 처리된 탄소재를 포함하는 탄소재 분산용액을 제조하는 단계;를 추가로 포함할 수 있다.Step (a) includes (a-1) preparing a carbon material solution containing a carbon material; (a-2) preparing a carbon material dispersion solution containing the carbon material subjected to primary ultrasonic treatment by first ultrasonicating the carbon material solution with either the low frequency or the high frequency ultrasound; And (a-3) secondary ultrasonic treatment of the carbon material dispersion solution of step (a-2) with another one of the low frequency and the high frequency ultrasonic waves to prepare a carbon material dispersion solution containing the secondary ultrasonic treated carbon material. It may additionally include a step of doing so.
상기 양극 활물질이 리튬철인산염계 산화물(lithium iron phosphate, LiFePO4), 리튬니켈코발트알루미늄계 산화물(NCA), 리튬코발트계 산화물(LiCoO2), 리튬니켈계 산화물(LiNiO2), 리튬망간계 산화물(LiMn2O4) 및 리튬니켈코발트망간계 산화물(NCM)로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있고, 바람직하게는 리튬니켈코발트망간계 산화물(NCM)을 포함할 수 있다.The positive electrode active material is lithium iron phosphate (LiFePO 4 ), lithium nickel cobalt aluminum oxide (NCA), lithium cobalt oxide (LiCoO 2 ), lithium nickel oxide (LiNiO 2 ), and lithium manganese oxide. (LiMn 2 O 4 ) and lithium nickel cobalt manganese oxide (NCM), and preferably lithium nickel cobalt manganese oxide (NCM).
상기 바인더가 폴리에틸렌옥사이드(polyethyleneoxide), 니트릴부타디엔러버(NBR, nitrile butadiene rubber), 폴리에틸렌글리콜(polyethyleneglycol), 폴리아크릴로니트릴(polyacrylonitrile), 폴리비닐클로라이드(polyvinylchloride), 폴리메틸메타크릴레이트(polymethylmethacrylate), 폴리프로필렌옥사이드(polypropyleneoxide), 폴리디메틸실록산(polydimethylsiloxane), 폴리비닐리덴플루오라이드(polyvinylidenefluoride), 폴리비닐리덴카보네이트(polyvinylidenecarbonate) 및 폴리비닐피롤리디논(polyvinyl pyrrolidinone)으로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있고, 바람직하게는 폴리비닐리덴플루오라이드(polyvinylidenefluoride)를 포함할 수 있다.The binder is polyethylene oxide, nitrile butadiene rubber (NBR), polyethylene glycol, polyacrylonitrile, polyvinyl chloride, polymethylmethacrylate, Contains at least one selected from the group consisting of polypropyleneoxide, polydimethylsiloxane, polyvinylidenefluoride, polyvinylidenecarbonate, and polyvinyl pyrrolidinone. It may contain polyvinylidene fluoride.
상기 양극 활물질 100 중량부에 대하여, 상기 탄소재 분산용액 1 내지 10 중량부; 상기 바인더 5 내지 20 중량부;를 포함할 수 있고, 바람직하게는 상기 탄소재 분산용액 2 내지 6 중량부; 상기 바인더 8 내지 15 중량부;를 포함할 수 있다.Based on 100 parts by weight of the positive electrode active material, 1 to 10 parts by weight of the carbon material dispersion solution; It may include 5 to 20 parts by weight of the binder, and preferably 2 to 6 parts by weight of the carbon material dispersion solution; It may include 8 to 15 parts by weight of the binder.
또한 본 발명은 상기 양극의 제조방법을 포함하는 리튬이차전지의 제조방법을 제공한다.Additionally, the present invention provides a method for manufacturing a lithium secondary battery including the method for manufacturing the positive electrode.
상기 리튬이차전지가 음극을 추가로 포함하고, 상기 음극이 리튬 금속을 포함할 수 있다.The lithium secondary battery may further include a negative electrode, and the negative electrode may include lithium metal.
상기 리튬이차전지가 전해질을 추가로 포함할 수 있다.The lithium secondary battery may additionally include an electrolyte.
상기 전해질이 에틸렌 카보네이트(ethylene carbonate, EC), 에틸메틸 카보네이트(ethylmethyl carbonate), 디메틸 카보네이트(dimethyl carbonate, DMC), 디에틸 카보네이트(diethyl carbonate, DEC), 아세토니트릴(acetonitrile, AC), 프로필렌 카보네이트(propylene carbonate, PC), 폴리에틸렌글리콜(polyehthylene glycol), 부틸렌 카보네이트(butylene carbonate, BC), 비닐렌 카보네이트(Vinylene carbonate, VC), 1,3-프로판설톤(1,3-propane sultone, PS), 플루오로에틸렌 카보네이트(fluoroethylene carbonate, FEC), 테트라히드로푸란, 1,2-디옥산, 2-메틸테트라히드로푸란, 부티로락톤, 디메틸포름아미드, 1,2 디메톡실에탄(DME) 및 석시노니트릴(Succinonitrile, SC)로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.The electrolyte is ethylene carbonate (EC), ethylmethyl carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), acetonitrile (AC), and propylene carbonate ( propylene carbonate (PC), polyethylene glycol, butylene carbonate (BC), vinylene carbonate (VC), 1,3-propane sultone (PS), Fluoroethylene carbonate (FEC), tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran, butyrolactone, dimethylformamide, 1,2 dimethoxylethane (DME), and succinonitrile. (Succinonitrile, SC).
[실시예][Example]
이하, 본 발명을 실시예를 들어 더욱 상세하게 설명하도록 한다. 그러나 이는 예시를 위한 것으로서 이에 의하여 본 발명의 범위가 한정되는 것은 아니다.Hereinafter, the present invention will be described in more detail through examples. However, this is for illustrative purposes only and does not limit the scope of the present invention.
실시예 1-1: 다주파 처리된 탄소나노튜브 분산용액(MF-CNT)의 제조Example 1-1: Preparation of multi-frequency treated carbon nanotube dispersion solution (MF-CNT)
평균 길이가 45μm인 탄소나노튜브(CNT) 2g을 200ml의 물에 용해시켜 1wt% 의 CNT 용액을 준비하였다. 상기 1wt%의 CNT 용액을 노즐 또는 프로브(Probe) 타입의 저주파 (17 kHz) 초음파 발진기를 통하여 분산 처리하여 저주파 처리된 CNT 분산용액을 제조하였다. 상기 저주파 처리된 CNT 분산용액을 수조(Bath) 타입의 고주파 (120 kHz) 초음파 발진기를 통하여 분산 처리하여 다주파 처리된 CNT 분산용액을 제조하였다. A 1 wt% CNT solution was prepared by dissolving 2 g of carbon nanotubes (CNT) with an average length of 45 μm in 200 ml of water. The 1 wt% CNT solution was dispersed through a nozzle or probe type low frequency (17 kHz) ultrasonic oscillator to prepare a low frequency treated CNT dispersion solution. The low-frequency treated CNT dispersion solution was dispersed through a bath-type high frequency (120 kHz) ultrasonic oscillator to prepare a multi-frequency treated CNT dispersion solution.
실시예 1-2: 다주파 처리된 탄소나노튜브 분산용액(MF-CNT)의 제조Example 1-2: Preparation of multi-frequency treated carbon nanotube dispersion solution (MF-CNT)
실시예 1-1에서 물(용매)을 사용하는 대신에 메틸피롤리돈(NMP, 용매)을 사용하는 것을 제외하고는 실시예 1-1과 동일한 방법으로 다주파 처리된 CNT 분산용액을 제조하였다.A multi-frequency treated CNT dispersion solution was prepared in the same manner as Example 1-1, except that methylpyrrolidone (NMP, solvent) was used instead of water (solvent) in Example 1-1. .
실시예 2: 양극의 제조Example 2: Preparation of anode
양극 활물질로서 NMC 811, 도전재로서 실시예 1-2에 따른 다주파 처리된 CNT 분산용액 및 바인더로서 폴리비닐리덴플루오라이드 (PVdF)를 혼합하였다. 이때, 양극 전체 중량을 기준으로, 합재는 양극 활물질:도전재:바인더 = 86:4:10 의 중량비로 혼합하였다. 즉 NMC 811 양극 활물질 100 중량부를 기준으로, 실시예 1-2에 따른 다주파 처리된 CNT 분산용액 4.65 중량부 및 PVdF 바인더 11.63 중량부를 혼합하였다.NMC 811 was mixed as a positive electrode active material, the multi-frequency treated CNT dispersion solution according to Example 1-2 as a conductive material, and polyvinylidene fluoride (PVdF) as a binder. At this time, based on the total weight of the positive electrode, the composite material was mixed at a weight ratio of positive electrode active material:conductive material:binder = 86:4:10. That is, based on 100 parts by weight of NMC 811 positive electrode active material, 4.65 parts by weight of the multi-frequency treated CNT dispersion solution according to Example 1-2 and 11.63 parts by weight of PVdF binder were mixed.
구체적으로, 먼저 NMC 811, 실시예 1-2에 따른 다주파 처리된 CNT 분산용액 및 PVdF 바인더를 상기 중량비로 칭량한 후, 페이스트 믹서를 통해 양극 슬러리를 제조하였다. 상기 양극 슬러리를 닥터블레이딩 (doctor-blading) 캐스팅 공법을 활용하여 두께가 20 μm인 알루미늄 호일에 도포하고 건조하여 합재의 로딩량이 12.8 mg/cm2인 양극을 제조하였다.Specifically, first, NMC 811, the multi-frequency treated CNT dispersion solution according to Example 1-2 and the PVdF binder were weighed at the above weight ratio, and then a positive electrode slurry was prepared through a paste mixer. The positive electrode slurry was applied to aluminum foil with a thickness of 20 μm using a doctor-blading casting method and dried to prepare a positive electrode with a composite loading of 12.8 mg/cm 2 .
소자실시예 1: 전지의 제조Device Example 1: Manufacturing of battery
실시예 2에 따라 제조된 양극과 리튬 호일을 음극으로 사용하여 2032 코인셀을 제조하였다. 이때, 16μm 두께의 다공성 폴리에틸렌 분리막(기공도 45%)을 사용하였고, 에틸렌 카보네이트(ethylene carbonate, EC):다이에틸 카보네이트 (diethyl carbonate, DEC)가 1:1의 부피비로 섞인 혼합 용매에 LiPF6 전해질을 1M의 농도로 용해시킨 전해액을 사용하였다.A 2032 coin cell was manufactured using the positive electrode prepared according to Example 2 and the lithium foil as the negative electrode. At this time, a 16μm thick porous polyethylene separator (porosity 45%) was used, and LiPF 6 electrolyte was added to a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC) in a volume ratio of 1:1. An electrolyte solution dissolved at a concentration of 1M was used.
비교예 1-1: 저주파 처리된 탄소나노튜브 분산용액(LF-CNT)의 제조Comparative Example 1-1: Preparation of low-frequency treated carbon nanotube dispersion solution (LF-CNT)
평균 길이가 45μm인 탄소나노튜브(CNT) 2g을 200ml의 물(용매)에 용해시켜 1wt% 의 CNT 용액을 준비하였다. 상기 1wt%의 CNT 용액을 노즐 또는 프로브(Probe) 타입의 저주파 (17 kHz) 초음파 발진기를 통하여 분산 처리하여 저주파 처리된 CNT 분산용액을 제조하였다.A 1 wt% CNT solution was prepared by dissolving 2 g of carbon nanotubes (CNT) with an average length of 45 μm in 200 ml of water (solvent). The 1 wt% CNT solution was dispersed through a nozzle or probe type low frequency (17 kHz) ultrasonic oscillator to prepare a low frequency treated CNT dispersion solution.
비교예 1-2: 저주파 처리된 탄소나노튜브 분산용액(LF-CNT)의 제조Comparative Example 1-2: Preparation of low-frequency treated carbon nanotube dispersion solution (LF-CNT)
비교예 1-1에서 물(용매)을 사용하는 대신에 메틸피롤리돈(NMP, 용매)을 사용하는 것을 제외하고는 비교예 1-1과 동일한 방법으로 저주파 처리된 CNT 분산용액을 제조하였다.A low-frequency treated CNT dispersion solution was prepared in the same manner as Comparative Example 1-1, except that methylpyrrolidone (NMP, solvent) was used instead of water (solvent) in Comparative Example 1-1.
비교예 2-1: 분산처리하지 않은 탄소나노튜브 용액(R-CNT)의 제조Comparative Example 2-1: Preparation of carbon nanotube solution (R-CNT) without dispersion treatment
평균 길이가 45μm인 탄소나노튜브(CNT) 2g을 200ml의 물(용매)에 용해시켜 1wt% 의 분산처리하지 않은 CNT 용액을 준비하였다. A 1 wt% undispersed CNT solution was prepared by dissolving 2 g of carbon nanotubes (CNT) with an average length of 45 μm in 200 ml of water (solvent).
비교예 2-2: 분산처리하지 않은 탄소나노튜브 용액(R-CNT)의 제조Comparative Example 2-2: Preparation of carbon nanotube solution (R-CNT) without dispersion treatment
비교예 2-1에서 물(용매)을 사용하는 대신에 메틸피롤리돈(NMP, 용매)을 사용하는 것을 제외하고는 비교예 2-1과 동일한 방법으로 분산처리하지 않은 CNT 용액을 준비하였다.A CNT solution without dispersion treatment was prepared in the same manner as in Comparative Example 2-1, except that methylpyrrolidone (NMP, solvent) was used instead of water (solvent) in Comparative Example 2-1.
비교예 3: 양극의 제조Comparative Example 3: Preparation of anode
실시예 2에서 실시예 1-2에 따른 다주파 처리된 CNT 분산용액을 사용하는 대신에 비교예 1-2에 따른 저주파 처리된 CNT 분산용액을 사용하는 것을 제외하고는 실시예 2와 동일한 방법으로 양극을 제조하였다. In Example 2, in the same manner as Example 2, except that instead of using the multi-frequency treated CNT dispersion solution according to Example 1-2, the low-frequency treated CNT dispersion solution according to Comparative Example 1-2 was used. An anode was manufactured.
비교예 4: 양극의 제조Comparative Example 4: Preparation of anode
실시예 2에서 실시예 1-2에 따른 다주파 처리된 CNT 분산용액을 사용하는 대신에 비교예 2-2에 따른 분산 처리하지 않은 CNT 용액을 사용하는 것을 제외하고는 실시예 2와 동일한 방법으로 양극을 제조하였다. In Example 2, in the same manner as Example 2, except that instead of using the multi-frequency treated CNT dispersion solution according to Example 1-2, the undispersed CNT solution according to Comparative Example 2-2 was used. An anode was manufactured.
소자비교예 1: 전지의 제조Device Comparative Example 1: Manufacturing of battery
소자실시예 1에서 실시예 2에 따라 제조된 양극을 사용하는 대신에 비교예 3에 따른 양극을 사용하는 것을 제외하고는 소자실시예 1과 동일한 방법으로 전지를 제조하였다.A battery was manufactured in the same manner as Device Example 1, except that the positive electrode according to Comparative Example 3 was used instead of the positive electrode manufactured according to Example 2 in Device Example 1.
소자비교예 2: 전지의 제조Device Comparative Example 2: Manufacturing of Battery
소자실시예 1에서 실시예 2에 따라 제조된 양극을 사용하는 대신에 비교예 4에 따른 양극을 사용하는 것을 제외하고는 소자실시예 1과 동일한 방법으로 전지를 제조하였다.A battery was manufactured in the same manner as Device Example 1, except that the positive electrode according to Comparative Example 4 was used instead of the positive electrode manufactured according to Example 2 in Device Example 1.
[시험예][Test example]
시험예 1: 분산성 평가Test Example 1: Dispersibility evaluation
도 3은 비교예 2-1(R-CNT), 실시예 1-1(MF-CNT) 및 3주 경과후 실시예 1-1(MF-CNT)에 따른 용액의 분산성을 평가하기 위한 광학이미지이다. Figure 3 shows optical measurements for evaluating the dispersibility of solutions according to Comparative Example 2-1 (R-CNT), Example 1-1 (MF-CNT), and Example 1-1 (MF-CNT) after 3 weeks. It is an image.
도 3에 따르면, 초음파 처리를 하지 않은 비교예 2-1(R-CNT)의 경우, 탄소나노튜브(CNT)가 분산되지 않고 가라앉는 반면, 다주파 처리된 CNT 분산용액(실시예 1-1, MF-CNT)의 경우, CNT 입자가 균일하게 분산되어있음을 확인 하였다. 특히, CNT의 용해도가 낮은 물을 용매(CNT의 용해도(Solubility (mg/L): NMP:~50, 물:<1) 로 사용함에도 불구하고 CNT가 응집하거나 또는 침전하지 않고 3주 이상 유지되는 결과를 확인하였다.According to Figure 3, in the case of Comparative Example 2-1 (R-CNT) without ultrasonic treatment, the carbon nanotubes (CNTs) did not disperse and settled, whereas the CNT dispersion solution treated with multiple frequencies (Example 1-1) , MF-CNT), it was confirmed that the CNT particles were uniformly dispersed. In particular, despite using water, which has low solubility of CNTs, as a solvent (Solubility of CNTs (mg/L): NMP: ~50, water: <1), CNTs do not aggregate or precipitate and remain for more than 3 weeks. The results were confirmed.
시험예 2: SEM 분석Test Example 2: SEM analysis
도 4는 실시예 1-2, 비교예 1-2 및 2-2에 따른 용액의 주사전자현미경(SEM) 이미지이고, 도 5는 실시예 2, 비교예 3 및 4에 따른 양극 합재의 주사전자현미경(SEM) 이미지이다.Figure 4 is a scanning electron microscope (SEM) image of the solutions according to Example 1-2 and Comparative Examples 1-2 and 2-2, and Figure 5 is a scanning electron microscope (SEM) image of the positive electrode composite according to Example 2 and Comparative Examples 3 and 4. This is a microscope (SEM) image.
도 4에 따르면, 분산처리 하지 않은 비교예 2-2의 경우, CNT 번들이 응집된 형상의 미세구조를 가지며, 응집체의 직경은 약 20 ~ 40μm 의 범위를 가진다. 또한 저주파 처리된 비교예 1-2의 경우는 CNT 번들의 응집체들이 분쇄된 형상의 미세구조를 가지며, 다주파 처리된 실시예 1-2의 경우는 CNT 번들이 잘 분산된 형상의 미세구조를 가지는 것을 확인할 수 있었다.According to FIG. 4, in the case of Comparative Example 2-2 without dispersion treatment, the CNT bundles had an aggregated microstructure, and the diameter of the aggregates ranged from about 20 to 40 μm. In addition, in the case of Comparative Example 1-2, which was treated at low frequency, the agglomerates of CNT bundles had a fine structure in a pulverized shape, and in the case of Example 1-2, which was processed at multiple frequencies, the CNT bundles had a fine structure in a well-dispersed shape. could be confirmed.
또한 도 5에 따르면, 분산 처리하지 않은 CNT를 포함하는 양극(비교예 4)에서 약 10 μm 직경의 CNT 번들 응집체를 확인하였으며, CNT와 양극 활물질 입자의 분산이 불균일한 것을 알 수 있었다. 또한 저주파 처리된 CNT를 포함하는 양극(비교예 3)에서 약 2μm 이하의 범위의 CNT 번들을 확인하였다. 또한 다주파 처리된 CNT를 포함하는 양극(실시예 2)은 CNT와 양극 활물질 및 바인더가 잘 분산되어 있는 형상의 미세구조를 가지는 것을 확인할 수 있었다.In addition, according to Figure 5, CNT bundle aggregates with a diameter of about 10 μm were confirmed in the positive electrode (Comparative Example 4) containing CNTs that were not dispersed, and it was found that the dispersion of CNTs and positive electrode active material particles was non-uniform. In addition, CNT bundles in the range of about 2 μm or less were confirmed in the anode containing CNTs treated at low frequency (Comparative Example 3). In addition, it was confirmed that the positive electrode containing multi-frequency treated CNTs (Example 2) had a microstructure in which the CNTs, positive electrode active material, and binder were well dispersed.
시험예 3: 입도 분석Test Example 3: Particle size analysis
도 6은 비교예 1-1, 비교예 2-1 및 실시예 1-1에 따른 용액의 입자 크기 분포를 나타낸 그래프이고, 도 7은 비교예 1-2, 비교예 2-2 및 실시예 1-2에 따른 용액의 입자 크기 분포를 나타낸 그래프이며, 입도분석장비 (Mastersizer 3000)를 이용하여 입자 크기 분포를 측정하였다.Figure 6 is a graph showing the particle size distribution of solutions according to Comparative Example 1-1, Comparative Example 2-1, and Example 1-1, and Figure 7 is a graph showing Comparative Example 1-2, Comparative Example 2-2, and Example 1. This is a graph showing the particle size distribution of the solution according to -2, and the particle size distribution was measured using a particle size analysis device (Mastersizer 3000).
도 6에 따르면, 물을 용매로서 사용한 경우로, 분산처리 하지 않은 CNT 용액(비교예 2-1)의 CNT 입자는 약 50 ~ 400μm 범위에 분포되어있음을 확인하였다. 또한 저주파 처리된 CNT 분산용액(비교예 1-1)의 CNT 입자 크기는 약 180μm에서 최빈수를 나타내며 균일하게 분산되어있음을 확인하였고, 다주파 처리된 CNT 분산용액(실시예 1-1)의 CNT 입자 크기는 약 100μm에서 최빈수를 나타내며 균일하게 분산되어있음을 확인하였다.According to Figure 6, in the case where water was used as a solvent, it was confirmed that the CNT particles of the CNT solution without dispersion treatment (Comparative Example 2-1) were distributed in the range of about 50 to 400 μm. In addition, the CNT particle size of the low-frequency treated CNT dispersion solution (Comparative Example 1-1) was confirmed to be uniformly dispersed with a mode at about 180 μm, and the CNT particle size of the multi-frequency treated CNT dispersion solution (Example 1-1) was confirmed to be uniformly dispersed. It was confirmed that the particle size was uniformly dispersed with a mode at about 100 μm.
도 7에 따르면, NMP를 용매로서 사용한 경우로, 분산처리 하지 않은 CNT 용액(비교예 2-2)의 CNT 입자는 약 7 ~ 200μm 범위에 분포되어있음을 확인하였고, 저주파 처리된 CNT 분산용액(비교예 1-2)의 CNT 입자 크기는 약 40μm에서 최빈수를 나타내며 균일하게 분산되어있음을 확인하였다. 또한 다주파 처리된 CNT 분산용액의 CNT 입자 크기는 약 17.5μm에서 최빈수를 나타내며 균일하게 분산되어있음을 확인하였다.According to Figure 7, when NMP was used as a solvent, it was confirmed that the CNT particles of the undispersed CNT solution (Comparative Example 2-2) were distributed in the range of about 7 to 200 μm, and the low-frequency treated CNT dispersion solution ( It was confirmed that the CNT particle size of Comparative Example 1-2) showed a mode of about 40 μm and was uniformly dispersed. In addition, it was confirmed that the CNT particle size of the multi-frequency treated CNT dispersion solution was uniformly dispersed with a mode at about 17.5 μm.
시험예 4: 점도 분석Test Example 4: Viscosity analysis
도 8은 비교예 1-1, 비교예 1-2, 비교예 2-1, 비교예 2-2, 실시예 1-1 및 실시예 1-2에 따른 용액의 점도를 비교한 그래프이다.Figure 8 is a graph comparing the viscosity of solutions according to Comparative Example 1-1, Comparative Example 1-2, Comparative Example 2-1, Comparative Example 2-2, Example 1-1, and Example 1-2.
도 8에 따르면, 실시예 1-1 및 1-2의 다주파 처리된 CNT 분산용액은 비교예 2-1 및 2-2의 분산처리 하지 않은 CNT 용액에 대하여 점도가 대폭 증가한 것을 알 수 있었다. 또한 비교예 1-1 및 1-2의 저주파 처리된 CNT 분산용액에 대해서도 약 2배 수준의 높은 점도 수치를 나타내 분산성이 대폭 향상된 것을 알 수 있었다. According to Figure 8, it was found that the viscosity of the multi-frequency treated CNT dispersion solutions of Examples 1-1 and 1-2 was significantly increased compared to the CNT solutions without dispersion treatment of Comparative Examples 2-1 and 2-2. In addition, the low-frequency treated CNT dispersion solutions of Comparative Examples 1-1 and 1-2 showed a viscosity value about twice as high, showing that the dispersibility was significantly improved.
시험예 5: 충방전 특성 분석Test Example 5: Charging/Discharging Characteristics Analysis
도 9는 소자실시예 1, 소자비교예 1 및 2에 따른 전지의 충방전 특성을 나타낸 그래프이다. 소자실시예 1, 소자비교예 1 및 2에 따른 코인형 전지를 각각 0.5 C로 2.8V에서 4.2V까지 2회 충방전을 실시하여 초기 충방전 용량을 측정하였다. Figure 9 is a graph showing the charge and discharge characteristics of batteries according to Device Example 1 and Device Comparative Examples 1 and 2. The coin-type batteries according to Device Example 1 and Device Comparative Examples 1 and 2 were each charged and discharged twice from 2.8 V to 4.2 V at 0.5 C to measure the initial charge and discharge capacity.
도 9에 따르면, 소자실시예 1에 따른 전지의 초기 방전 용량은 242.18 mAh/gNMC으로, 소자비교예 1 및 2에 따른 전지의 초기 충방전 용량인 178.04 mAh/gNMC, 106.69 mAh/gNMC보다 초기 충방전 용량이 상승되었음을 확인할 수 있다. 즉, 다주파 처리된 CNT 분산용액을 도전재로서 사용함으로써, 양극 활물질과 입자들 사이의 공극에 도전재가 이상적으로 분포하여 양극 활물질의 활용률을 극대화하였음을 확인하였다. 반면, 소자비교예 1 및 2는 도전재가 양극 활물질과 균일하게 혼합되지 못하여 충분하지 못한 초기 충방전 용량을 나타내는 것을 알 수 있다.According to Figure 9, the initial discharge capacity of the battery according to Device Example 1 is 242.18 mAh/gNMC, which is higher than the initial charge and discharge capacity of 178.04 mAh/gNMC and 106.69 mAh/gNMC of the battery according to Device Comparative Examples 1 and 2. It can be confirmed that the discharge capacity has increased. In other words, it was confirmed that by using the multi-frequency treated CNT dispersion solution as a conductive material, the conductive material was ideally distributed in the pores between the positive electrode active material and the particles, thereby maximizing the utilization rate of the positive electrode active material. On the other hand, it can be seen that Device Comparative Examples 1 and 2 showed insufficient initial charge and discharge capacity because the conductive material was not uniformly mixed with the positive electrode active material.
시험예 6: 율속 변화 테스트Test Example 6: Rate change test
도 10은 소자실시예 1, 소자비교예 1 및 2에 따른 전지의 율속 변화를 나타낸 그래프이다. 소자실시예 1, 소자비교예 1 및 2에 따른 코인형 전지를 각각 0.2 C, 0.5 C, 1 C, 2 C, 3 C, 5 C, 0.2 C로 전류량을 변화하여 3.0V에서 4.2V까지 C-rate 테스트를 진행하였다.Figure 10 is a graph showing the rate change of the battery according to Device Example 1 and Device Comparative Examples 1 and 2. Coin-type batteries according to Device Example 1 and Device Comparative Examples 1 and 2 were changed from 3.0V to 4.2V by changing the current amount to 0.2 C, 0.5 C, 1 C, 2 C, 3 C, 5 C, and 0.2 C, respectively. -rate test was conducted.
도 10에 따르면, 소자실시예 1, 소자비교예 1 및 2 모두 인가되는 전류량이 증가함에 따라 용량의 감소가 관찰 되었으며, 그 중에서도 소자실시예 1의 충방전 용량이 가장 개선 되었음을 확인할 수 있다. 또한, 소자비교예 2의 경우 3 C이상에서의 율속에서 충방전 특성을 보이지 못했으나 소자실시예 1과 소자비교예 1의 경우 3 C에서의 율속에서도 충방전 특성을 보였다. 35 회의 사이클 후 0.2 C에서의 율속에서 소자실시예 1에 따른 전지는 92.37%의 초기 용량을 유지한 반면, 소자비교예 1에 따른 전지는 88.87%의 감소된 초기 용량을 보였다. 즉, 도전재로 사용되는 CNT 분산용액의 저주파 처리로도 방전 용량의 개선을 보이며, 다주파 처리까지 한 경우 충방전 용량이 가장 개선됨을 알 수 있었다.According to FIG. 10, a decrease in capacity was observed in both Device Example 1 and Device Comparative Examples 1 and 2 as the amount of applied current increased. Among them, it can be seen that the charge/discharge capacity of Device Example 1 was the most improved. In addition, in the case of Device Comparative Example 2, charge and discharge characteristics were not shown at a rate of 3 C or higher, but in the case of Device Example 1 and Device Comparative Example 1, charge and discharge characteristics were shown even at a rate of 3 C. After 35 cycles, at a rate of 0.2 C, the battery according to Device Example 1 maintained an initial capacity of 92.37%, while the battery according to Device Comparative Example 1 showed a reduced initial capacity of 88.87%. In other words, it was found that the discharge capacity was improved even with low-frequency treatment of the CNT dispersion solution used as a conductive material, and that the charge-discharge capacity was most improved when multi-frequency treatment was performed.
시험예 7: 수명(cycle) 측정Test Example 7: Life (cycle) measurement
도 11은 소자실시예 1, 소자비교예 1 및 2에 따른 전지의 사이클 특성을 나타낸 그래프이다. 소자실시예 1, 소자비교예 1 및 2에 따른 코인형 전지를 각각 0.5 C로 3.0V에서 4.2V 범위 내에서 충방전 수명 테스트를 수행하였다.Figure 11 is a graph showing the cycle characteristics of batteries according to Device Example 1 and Device Comparative Examples 1 and 2. A charge/discharge life test was performed on the coin-type batteries according to Device Example 1 and Device Comparative Examples 1 and 2, respectively, within the range of 3.0V to 4.2V at 0.5 C.
도 11에 따르면, 소자실시예 1, 소자비교예 1 및 2에 따른 각 전지의 50회 사이클 후 각 89.82%, 95.57% 및 98.86%의 초기용량 유지율을 나타내었다. 그러나, 소자실시예 1에 따른 전지의 50회 사이클 평균 방전 용량은 227.5 mAh/gNMC으로, 소자비교예 1 및 2에 따른 전지의 50회 사이클 평균 방전 용량인 178.6 mAh/gNMC, 127.3 mAh/gNMC보다 평균 방전 용량이 개선되었음을 확인할 수 있었다.According to Figure 11, each battery according to Device Example 1 and Device Comparative Examples 1 and 2 showed initial capacity maintenance rates of 89.82%, 95.57%, and 98.86% after 50 cycles, respectively. However, the average discharge capacity of the battery according to Device Example 1 over 50 cycles is 227.5 mAh/gNMC, which is lower than the average discharge capacity of 178.6 mAh/gNMC and 127.3 mAh/gNMC over 50 cycles of the battery according to Device Comparative Examples 1 and 2. It was confirmed that the average discharge capacity was improved.
시험예 8: 전극 저항률(electrode resistance) 측정Test Example 8: Electrode resistance measurement
도 12는 실시예 2, 비교예 3 및 비교예 4에 따른 전극 합재의 체적 저항률을 측정하여 나타낸 그래프이고, 도 13은 실시예 2, 비교예 3 및 비교예 4에 따른 전극의 합재와 집전체의 계면 저항을 측정하여 나타낸 그래프이며, 전극저항 측정 장비(RM2610)을 이용하여 측정하였다.Figure 12 is a graph showing the volume resistivity of electrode mixtures according to Example 2, Comparative Example 3, and Comparative Example 4, and Figure 13 is a graph showing the electrode mixture and current collector according to Example 2, Comparative Example 3, and Comparative Example 4. This is a graph showing the measured interface resistance, and was measured using an electrode resistance measuring device (RM2610).
도 12에 따르면, 실시예 2에 따른 전극 합재의 체적 저항률인 1.103 Ωcm의 측정값으로, 비교예 3 및 4에 따른 전극 합재의 체적 저항률인 1.303 Ωcm 및 3.266 Ωcm의 측정값과 비교하여 체적 저항이 감소됨을 확인할 수 있었다. 즉, 다주파 처리의 경우 도전재의 이상적인 분포로 인한 저항감소 및 이로 인한 전기전도도의 향상을 예상할 수 있었다.According to Figure 12, the measured value of 1.103 Ωcm, which is the volume resistivity of the electrode mixture according to Example 2, is compared to the measured values of 1.303 Ωcm and 3.266 Ωcm, which are the volume resistivity of the electrode mixture according to Comparative Examples 3 and 4. It was confirmed that there was a decrease. In other words, in the case of multi-frequency treatment, a decrease in resistance due to the ideal distribution of the conductive material and an improvement in electrical conductivity could be expected.
또한, 도 13에 따르면, 실시예 2에 따른 전극의 계면 저항이 0.471 Ωcm2의 측정값으로, 비교예 3 및 4에 따른 전극의 계면 저항 측정값인 0.983 Ωcm2 및 1.433 Ωcm2의 측정값과 비교하여 계면 저항이 감소됨을 확인할 수 있었다.In addition, according to FIG. 13, the measured interfacial resistance of the electrode according to Example 2 is 0.471 Ωcm 2 , and the measured interfacial resistance of the electrode according to Comparative Examples 3 and 4 is 0.983 Ωcm 2 and 1.433 Ωcm 2 By comparison, it was confirmed that the interface resistance was reduced.
이상, 본 발명의 바람직한 실시예들에 대하여 설명하였으나, 해당 기술 분야에서 통상의 지식을 가진 자라면 특허청구범위에 기재된 본 발명의 사상으로부터 벗어나지 않는 범위 내에서, 구성 요소의 부가, 변경, 삭제 또는 추가 등에 의해 본 발명을 다양하게 수정 및 변경시킬 수 있을 것이며, 이 또한 본 발명의 권리범위 내에 포함된다고 할 것이다. 예를 들어, 단일형으로 설명되어 있는 각 구성 요소는 분산되어 실시될 수도 있으며, 마찬가지로 분산된 것으로 설명되어 있는 구성 요소들도 결합된 형태로 실시될 수 있다. 본 발명의 범위는 상기 상세한 설명보다는 후술하는 특허청구범위에 의하여 나타내어지며, 특허청구범위의 의미 및 범위 그리고 그 균등 개념으로부터 도출되는 모든 변경 또는 변형된 형태가 본 발명의 범위에 포함되는 것으로 해석되어야 한다.Although the preferred embodiments of the present invention have been described above, those skilled in the art will be able to add, change, delete or modify components without departing from the spirit of the present invention as set forth in the patent claims. The present invention may be modified and changed in various ways by addition, etc., and this will also be included within the scope of rights of the present invention. For example, each component described as single may be implemented in a distributed manner, and similarly, components described as distributed may also be implemented in a combined form. The scope of the present invention is indicated by the claims described below rather than the detailed description above, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. do.

Claims (20)

  1. (a) 탄소재를 포함하는 탄소재 용액을 제조하는 단계;(a) preparing a carbon material solution containing carbon material;
    (b) 상기 탄소재 용액을 1차 초음파 처리하여 1차 초음파 처리된 탄소재를 포함하는 제1 탄소재 분산용액을 제조하는 단계; 및(b) subjecting the carbon material solution to primary ultrasonic treatment to prepare a first carbon material dispersion solution containing the carbon material subjected to primary ultrasonic treatment; and
    (c) 상기 1차 탄소재 분산용액을 2차 초음파 처리하여 2차 초음파 처리된 탄소재를 포함하는 제2 탄소재 분산용액을 제조하는 단계;를 포함하는 것을 특징으로 하는 탄소재 분산용액의 제조방법.(c) processing the primary carbon material dispersion solution with secondary ultrasonic waves to prepare a second carbon material dispersion solution containing the secondary ultrasonic treated carbon material; Preparation of a carbon material dispersion solution comprising a. method.
  2. 제1항에 있어서, According to paragraph 1,
    상기 1차 초음파 처리는 저주파를 사용하는 저주파 처리이고,The first ultrasonic treatment is a low-frequency treatment using low frequencies,
    상기 2차 초음파 처리는 고주파를 사용하는 고주파 처리인 것을 특징으로 하는 탄소재 분산용액의 제조방법.A method for producing a carbon material dispersion solution, characterized in that the secondary ultrasonic treatment is a high-frequency treatment using high frequencies.
  3. 제2항에 있어서, According to paragraph 2,
    상기 저주파 처리가 10 내지 45 kHz에서 수행되고,The low frequency processing is performed at 10 to 45 kHz,
    상기 고주파 처리가 35 내지 180 kHz에서 수행되고,The high-frequency processing is performed at 35 to 180 kHz,
    상기 고주파의 주파수가 상기 저주파의 주파수보다 큰 것을 특징으로 하는 탄소재 분산용액의 제조방법.A method for producing a carbon material dispersion solution, characterized in that the frequency of the high frequency is greater than the frequency of the low frequency.
  4. 제3항에 있어서, According to paragraph 3,
    상기 저주파 처리가 10 내지 35 kHz에서 수행되고,The low frequency processing is performed at 10 to 35 kHz,
    상기 고주파 처리가 40 내지 180 kHz에서 수행되는 것을 특징으로 하는 탄소재 분산용액의 제조방법.A method for producing a carbon material dispersion solution, characterized in that the high-frequency treatment is performed at 40 to 180 kHz.
  5. 제4항에 있어서, According to paragraph 4,
    상기 고주파와 저주파의 주파수 차이가 10 내지 170 kHz인 것을 특징으로 하는 탄소재 분산용액의 제조방법.A method for producing a carbon material dispersion solution, characterized in that the frequency difference between the high frequency and the low frequency is 10 to 170 kHz.
  6. 제1항에 있어서, According to paragraph 1,
    상기 1차 초음파 처리 및 상기 2차 초음파 처리는 각각 노즐 타입(Nozzle-Type), 프로브 타입(Probe-Type), 수조 타입(Bath-Type), 각형의 수조 타입(Bath-Type) 및 원통형의 수조 타입(Bath-Type)으로 이루어진 군으로부터 선택된 1종 이상의 초음파 처리기로 수행되는 것을 특징으로 하는 탄소재 분산용액의 제조방법.The first ultrasonic treatment and the second ultrasonic treatment are performed using a nozzle-type, probe-type, bath-type, prismatic bath-type, and cylindrical bath, respectively. A method for producing a carbon material dispersion solution, characterized in that it is performed using at least one type of ultrasonic processor selected from the group consisting of Bath-Type.
  7. 제1항에 있어서, According to paragraph 1,
    상기 탄소재가 탄소나노튜브, 카본블랙, 그래핀, 아세틸렌 블랙, 덴카 블랙, 흑연 및 활성탄으로 이루어진 군으로부터 선택된 1종 이상을 포함하는 것을 특징으로 하는 탄소재 분산용액의 제조방법.A method for producing a carbon material dispersion solution, wherein the carbon material includes at least one selected from the group consisting of carbon nanotubes, carbon black, graphene, acetylene black, Denka black, graphite, and activated carbon.
  8. 제7항에 있어서, In clause 7,
    상기 탄소재가 탄소나노튜브를 포함하는 것을 특징으로 하는 탄소재 분산용액의 제조방법.A method for producing a carbon material dispersion solution, characterized in that the carbon material includes carbon nanotubes.
  9. 제1항에 있어서, According to paragraph 1,
    상기 탄소재 용액이 용매를 추가로 포함하는 것을 특징으로 하는 탄소재 분산용액의 제조방법.A method for producing a carbon material dispersion solution, characterized in that the carbon material solution further includes a solvent.
  10. 제9항에 있어서, According to clause 9,
    상기 용매가 물, 에탄올, 이소프로필알코올(IPA), 디메틸포름아미드(DMF) 및 메틸피롤리돈(NMP)으로 이루어진 군으로부터 선택된 1종 이상을 포함하는 것을 특징으로 하는 탄소재 분산용액의 제조방법.A method for producing a carbon material dispersion solution, wherein the solvent includes at least one selected from the group consisting of water, ethanol, isopropyl alcohol (IPA), dimethylformamide (DMF), and methylpyrrolidone (NMP). .
  11. 제1항에 있어서,According to paragraph 1,
    상기 2차 초음파 처리된 탄소재의 평균입도가 상기 탄소재의 평균입도보다 작은 것을 특징으로 하는 탄소재 분산용액의 제조방법.A method for producing a carbon material dispersion solution, characterized in that the average particle size of the secondary ultrasonic treated carbon material is smaller than the average particle size of the carbon material.
  12. (a) 탄소재를 포함하는 탄소재 용액을 저주파의 초음파 및 고주파의 초음파로 각각 처리하여 탄소재 분산용액을 제조하는 단계;(a) preparing a carbon material dispersion solution by treating a carbon material solution containing carbon material with low-frequency ultrasound and high-frequency ultrasound, respectively;
    (b) 양극 활물질, 상기 탄소재 분산용액, 바인더를 포함하는 양극 슬러리를 제조하는 단계; 및(b) preparing a positive electrode slurry containing a positive electrode active material, the carbon material dispersion solution, and a binder; and
    (c) 상기 양극 슬러리를 집전체의 일면 또는 양면 상에 도포하고 건조하여 양극을 제조하는 단계;를(c) manufacturing a positive electrode by applying the positive electrode slurry on one or both sides of a current collector and drying it;
    포함하는 양극의 제조방법.A method of manufacturing an anode comprising:
  13. 제12항에 있어서, According to clause 12,
    단계 (a)가,Step (a) is,
    (a-1) 탄소재를 포함하는 탄소재 용액을 제조하는 단계;(a-1) preparing a carbon material solution containing carbon material;
    (a-2) 상기 탄소재 용액을 상기 저주파 및 상기 고주파의 초음파 중 어느 하나로 1차 초음파 처리하여 1차 초음파 처리된 탄소재를 포함하는 탄소재 분산용액을 제조하는 단계; 및(a-2) preparing a carbon material dispersion solution containing the carbon material subjected to primary ultrasonic treatment by first ultrasonicating the carbon material solution with either the low frequency or the high frequency ultrasound; and
    (a-3) 단계 (a-2)의 상기 탄소재 분산용액을 상기 저주파 및 상기 고주파의 초음파 중 다른 하나로 2차 초음파 처리하여 2차 초음파 처리된 탄소재를 포함하는 탄소재 분산용액을 제조하는 단계;를 추가로 포함하는 것을 특징으로 하는 양극의 제조방법.(a-3) secondary ultrasonic treatment of the carbon material dispersion solution of step (a-2) with one of the low frequency and high frequency ultrasound waves to produce a carbon material dispersion solution containing the secondary ultrasonic treated carbon material. A method of manufacturing an anode, characterized in that it further comprises a step.
  14. 제12항에 있어서, According to clause 12,
    상기 양극 활물질이 리튬철인산염계 산화물(lithium iron phosphate, LiFePO4), 리튬니켈코발트알루미늄계 산화물(NCA), 리튬코발트계 산화물(LiCoO2), 리튬니켈계 산화물(LiNiO2), 리튬망간계 산화물(LiMn2O4) 및 리튬니켈코발트망간계 산화물(NCM)로 이루어진 군으로부터 선택된 1종 이상을 포함하는 것을 특징으로 하는 양극의 제조방법．The positive electrode active material is lithium iron phosphate (LiFePO4), lithium nickel cobalt aluminum oxide (NCA), lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), and lithium manganese oxide (LiMn 2) . O 4 ) and lithium nickel cobalt manganese oxide (NCM). A method for producing a positive electrode comprising at least one selected from the group consisting of.
  15. 제12항에 있어서, According to clause 12,
    상기 바인더가 폴리에틸렌옥사이드(polyethyleneoxide), 니트릴부타디엔러버(NBR, nitrile butadiene rubber), 폴리에틸렌글리콜(polyethyleneglycol), 폴리아크릴로니트릴(polyacrylonitrile), 폴리비닐클로라이드(polyvinylchloride), 폴리메틸메타크릴레이트(polymethylmethacrylate), 폴리프로필렌옥사이드(polypropyleneoxide), 폴리디메틸실록산(polydimethylsiloxane), 폴리비닐리덴플루오라이드(polyvinylidenefluoride), 폴리비닐리덴카보네이트(polyvinylidenecarbonate) 및 폴리비닐피롤리디논(polyvinyl pyrrolidinone)으로 이루어진 군으로부터 선택된 1종 이상을 포함하는 것을 특징으로 하는 양극의 제조방법.The binder is polyethylene oxide, nitrile butadiene rubber (NBR), polyethylene glycol, polyacrylonitrile, polyvinyl chloride, polymethylmethacrylate, Contains at least one selected from the group consisting of polypropyleneoxide, polydimethylsiloxane, polyvinylidenefluoride, polyvinylidenecarbonate, and polyvinyl pyrrolidinone. A method of manufacturing an anode, characterized in that.
  16. 제12항에 있어서, According to clause 12,
    상기 양극 활물질 100 중량부에 대하여,For 100 parts by weight of the positive electrode active material,
    상기 탄소재 분산용액 1 내지 10 중량부;1 to 10 parts by weight of the carbon material dispersion solution;
    상기 바인더 5 내지 20 중량부;를 포함하는 것을 특징으로 하는 양극의 제조방법.A method of manufacturing a positive electrode comprising 5 to 20 parts by weight of the binder.
  17. 제12항의 양극의 제조방법을 포함하는 리튬이차전지의 제조방법.A method of manufacturing a lithium secondary battery comprising the method of manufacturing the positive electrode of claim 12.
  18. 제17항에 있어서,According to clause 17,
    상기 리튬이차전지가 음극을 추가로 포함하고, The lithium secondary battery further includes a negative electrode,
    상기 음극이 리튬 금속을 포함하는 것을 특징으로 하는 리튬이차전지의 제조방법.A method of manufacturing a lithium secondary battery, characterized in that the negative electrode contains lithium metal.
  19. 제17항에 있어서,According to clause 17,
    상기 리튬이차전지가 전해질을 추가로 포함하는 것을 특징으로 하는 리튬이차전지의 제조방법.A method of manufacturing a lithium secondary battery, characterized in that the lithium secondary battery further includes an electrolyte.
  20. 제19항에 있어서,According to clause 19,
    상기 전해질이 에틸렌 카보네이트(ethylene carbonate, EC), 에틸메틸 카보네이트(ethylmethyl carbonate), 디메틸 카보네이트(dimethyl carbonate, DMC), 디에틸 카보네이트(diethyl carbonate, DEC), 아세토니트릴(acetonitrile, AC), 프로필렌 카보네이트(propylene carbonate, PC), 폴리에틸렌글리콜(polyehthylene glycol), 부틸렌 카보네이트(butylene carbonate, BC), 비닐렌 카보네이트(Vinylene carbonate, VC), 1,3-프로판설톤(1,3-propane sultone, PS), 플루오로에틸렌 카보네이트(fluoroethylene carbonate, FEC), 테트라히드로푸란, 1,2-디옥산, 2-메틸테트라히드로푸란, 부티로락톤, 디메틸포름아미드, 1,2 디메톡실에탄(DME) 및 석시노니트릴(Succinonitrile, SC)로 이루어진 군으로부터 선택된 1종 이상을 포함하는 것을 특징으로 하는 리튬이차전지의 제조방법.The electrolyte is ethylene carbonate (EC), ethylmethyl carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), acetonitrile (AC), and propylene carbonate ( propylene carbonate (PC), polyethylene glycol, butylene carbonate (BC), vinylene carbonate (VC), 1,3-propane sultone (PS), Fluoroethylene carbonate (FEC), tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran, butyrolactone, dimethylformamide, 1,2 dimethoxylethane (DME), and succinonitrile. (Succinonitrile, SC). A method of manufacturing a lithium secondary battery, characterized in that it includes one or more species selected from the group consisting of (Succinonitrile, SC).
PCT/KR2023/005680 2022-07-29 2023-04-26 Preparation method for carbon material dispersion solution by using multi-frequency dispersion and preparation method for positive electrode comprising carbon material dispersion solution WO2024025084A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100664664B1 (en) * 2005-12-30 2007-01-04 엔바로테크 주식회사 Method and apparatus for manufacturing colloidal carbon nano homogeneously dispersed in aqueous solution
KR100827649B1 (en) * 2007-01-17 2008-05-07 한양대학교 산학협력단 Fabrication method of carbon nanotube thin film
JP5861646B2 (en) * 2010-12-20 2016-02-16 日本電気株式会社 Method for producing carbon nanotube dispersed paste
KR20160062172A (en) * 2013-12-23 2016-06-01 베이징 어글레이어 테크놀러지 디벨롭먼트 컴퍼니 리미티드 Method for uniform dispersion of single-wall carbon nanotubes
KR20170049459A (en) * 2015-10-28 2017-05-10 주식회사 엘지화학 Conductive material dispersed solution and lithium secondary battery prepared by using the same

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100664664B1 (en) * 2005-12-30 2007-01-04 엔바로테크 주식회사 Method and apparatus for manufacturing colloidal carbon nano homogeneously dispersed in aqueous solution
KR100827649B1 (en) * 2007-01-17 2008-05-07 한양대학교 산학협력단 Fabrication method of carbon nanotube thin film
JP5861646B2 (en) * 2010-12-20 2016-02-16 日本電気株式会社 Method for producing carbon nanotube dispersed paste
KR20160062172A (en) * 2013-12-23 2016-06-01 베이징 어글레이어 테크놀러지 디벨롭먼트 컴퍼니 리미티드 Method for uniform dispersion of single-wall carbon nanotubes
KR20170049459A (en) * 2015-10-28 2017-05-10 주식회사 엘지화학 Conductive material dispersed solution and lithium secondary battery prepared by using the same

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
송서원 등. 다중 주파수 분산 기술을 이용한 이차 전지 양극재용 탄소나노튜브 개발. 2022년 한국섬유공학회 춘계학술대회. 27-29 April 2022, pp. 1-3 (SONG, Seowon et al. Development of carbon nanotubes as cathode materials for rechargeable batteries using method of multi-frequency dispersion technology. 2022 Spring Conference of the Korean Fiber Society.) *

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