WO2022097832A1 - Anode active material for lithium secondary battery, preparation method therefor, and lithium secondary battery including same - Google Patents

Anode active material for lithium secondary battery, preparation method therefor, and lithium secondary battery including same Download PDF

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WO2022097832A1
WO2022097832A1 PCT/KR2020/018452 KR2020018452W WO2022097832A1 WO 2022097832 A1 WO2022097832 A1 WO 2022097832A1 KR 2020018452 W KR2020018452 W KR 2020018452W WO 2022097832 A1 WO2022097832 A1 WO 2022097832A1
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secondary battery
lithium secondary
active material
shell
negative electrode
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PCT/KR2020/018452
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French (fr)
Korean (ko)
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김창준
지대훈
김일한
안현준
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(주)뉴테크엘아이비
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Priority claimed from KR1020200170599A external-priority patent/KR102601864B1/en
Application filed by (주)뉴테크엘아이비 filed Critical (주)뉴테크엘아이비
Publication of WO2022097832A1 publication Critical patent/WO2022097832A1/en

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/02—Silicon
    • 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
    • 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
    • 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
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • 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
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • 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 an anode active material for a lithium secondary battery and a method for manufacturing the same.
  • a polymer binder with restorative capability is surrounded by nanoparticles formed in a core-shell structure of silicon, silicon oxide, and carbon, and consists of a silicon-carbon-lithium-polymer binder, so that the expansion and It is possible to prevent detachment of particles due to shrinkage and improve the lifespan of the secondary battery.
  • the theoretical capacity of silicon is 4,200 mAh/g, which is the highest among materials applicable to the negative electrode of a lithium-ion battery.
  • Silicon has advantages of high output and low price, but there is a problem in that a phase change occurs due to the reverse insertion and separation of lithium ions, and thus the volume expands by more than 300%.
  • the stress inside the silicon causes cracks, which causes the structure to collapse. This structural collapse of the silicon blocks electron transfer in the electrode, resulting in an unusable space in the electrode, resulting in a decrease in the capacity and lifespan of the silicon.
  • Silicide may be used to suppress volume expansion of silicon.
  • a metal-based material is used to relieve volume expansion, there is a disadvantage in that the electronic conductivity is high but the ionic conductivity is lowered, so that the lifespan characteristic is deteriorated.
  • Carbon-based materials have high strength, high ionic and electronic conductivity, excellent charge and discharge properties, and are stable because dendrite structures are not formed.
  • the theoretical charging capacity of the graphite is only 372 mAh/g.
  • Patent Document 0001 Patent Publication No. KR 10-2017-0120940
  • the present application is intended to solve the problems of the prior art described above, and a polymer binder with restorative capability is surrounded by nanoparticles formed of silicon, silicon oxide and carbon in a core-shell structure, thereby preventing the expansion and contraction of silicon. It achieves the effect of preventing the detachment of particles due to the effect and improving the lifespan of the secondary battery.
  • the anode active material for a lithium secondary battery of the present invention for achieving the above technical problem is nanoparticles; and a polymer binder surrounding at least one or more of the nanoparticles, wherein the nanoparticles include: a core including silicon; a first shell formed on the surface of the core and including silicon oxide; and a second shell formed on the surface of the first shell and including carbon.
  • the silicon core may be doped with lithium, but is not limited thereto.
  • the diameter of the nanoparticles may be 10 nm to 500 ⁇ m, but is not limited thereto.
  • the thickness of the first shell may be 0.1 nm to 100 nm, but is not limited thereto.
  • the thickness of the second shell may be 10 nm to 50 nm, but is not limited thereto.
  • the polymer binder may be one in which two or more polymers are crosslinked and have conductivity and restorative elasticity, but is not limited thereto.
  • the polymer binder may include a polymer selected from the group consisting of polyacrylic acid, polyvinyl alcohol, polyvinyl acrylic acid, polyamide, polyvinylithene, polyamideimide, polyethylene, polypropylene, and combinations thereof. It is not limited.
  • the polymer binder may be one in which polyacrylic acid and polyvinyl alcohol are crosslinked, but is not limited thereto.
  • the silicon oxide may be SiO x , and x may be 0.1 to 1.6, but is not limited thereto.
  • the silicon may be crystalline or amorphous, but is not limited thereto.
  • a method of manufacturing an anode active material for a lithium secondary battery includes drying silicon core particles; oxidizing the silicon core particles under an oxidizing agent to form a first shell including silicon oxide on the silicon core particles; forming a second shell including carbon on the surface of the first shell by mixing the particles on which the first shell is formed with a carbon source and performing a first heat treatment; preparing a mixture by mixing the particles on which the second shell is formed with a polymer binder; pressurizing and heat-treating the mixture; and pulverizing the pressurized and second heat-treated mixture.
  • mixing the silicon core particles with a lithium compound may further include, but is not limited thereto.
  • the lithium compound may be lithium hydroxide or lithium carbonate, but is not limited thereto.
  • the drying may include drying the silicon core particles to a moisture content of 1% to 20%, but is not limited thereto.
  • the polymer binder may be one in which two or more polymers are crosslinked, but is not limited thereto.
  • the crosslinking is performed by mixing two or more polymers selected from polyacrylic acid, polyvinyl alcohol, polyacryl acrylate, polyvinyl acrylic acid, polyamide, polyvinylithene, polyamideimide, polyethylene and polypropylene, citric acid, glycerol and liquid copper. It may be done, but is not limited thereto.
  • the crosslinking may be formed by reacting at a temperature of 30°C to 80°C for 1 hour to 3 hours, but is not limited thereto.
  • the pressurization may be to apply a pressure of 1 ton/cm 2 to 20 ton/cm 2 , but is not limited thereto.
  • the second heat treatment may be performed at a temperature of 150°C to 800°C, but is not limited thereto.
  • the carbon source may be selected from the group consisting of graphene, graphite, hard carbon, soft carbon, natural graphite, artificial graphite, pitch, carbon black, and combinations thereof, but is not limited thereto.
  • the lithium secondary battery includes the anode active material for the lithium secondary battery.
  • the disclosed technology may have the following effects. However, this does not mean that a specific embodiment should include all of the following effects or only the following effects, so the scope of the disclosed technology should not be construed as being limited thereby.
  • the polymer binder according to the present application is made of two or more polymers cross-linked, so that expansion and contraction are freely possible, so that it can serve as a "smart ball".
  • the smart ball can help the silicon to shrink to its original shape after expansion when the negative active material for the lithium secondary battery is applied to the lithium secondary battery and voltage is applied. Since the smart ball is not only expandable but also contracted freely, the characteristics of the lithium secondary battery are reversible, so that the coulombic efficiency, periodicity, charge/discharge rate, lifespan, etc. can be improved. In addition, since it helps to maintain electrical contact between the core, the first shell, and the second shell, it is possible to prevent breakage, detachment, and the like due to excessive expansion.
  • FIG. 1 is a view of an anode active material for a lithium secondary battery according to an embodiment of the present application.
  • FIG. 2 is a view of an anode active material for a lithium secondary battery according to an embodiment of the present application.
  • FIG. 3 is a flowchart of a method of manufacturing a negative active material for a lithium secondary battery according to an embodiment of the present application.
  • FIG. 5 is a FIB (focused ion beam) image of the nanoparticles prepared according to the present embodiment.
  • FIG. 6 is a TEM-mapping (transmission electron microscope mapping) image of nanoparticles prepared according to the present embodiment.
  • SEM 7 is a scanning electron microscope (SEM) image of nanoparticles prepared according to the present embodiment.
  • 8A to 8D are transmission electron microscope mapping (TEM-mapping) images of nanoparticles prepared according to the present embodiment.
  • FIG. 9 is a TEM (transmission electron microscope) image of the anode active material for a lithium secondary battery prepared according to the present embodiment.
  • SEM 10 is a scanning electron microscope (SEM) image of an anode active material for a lithium secondary battery manufactured according to this embodiment.
  • FIG. 11 is a view showing the configuration of the secondary battery coin cell according to the present manufacturing example.
  • FIG. 12 is a graph showing the change in capacity according to the cycle of the coin cell of the secondary battery according to the present preparation example.
  • 13 is a graph showing the change in capacity retention rate according to the cycle of the coin cell of the secondary battery according to the present preparation example.
  • a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.
  • the term “and/or” includes a combination of a plurality of related listed items or any of a plurality of related listed items.
  • nanoparticles and a polymer binder surrounding at least one or more of the nanoparticles, wherein the nanoparticles include: a core including silicon; a first shell formed on the surface of the core and including silicon oxide; and a second shell formed on the surface of the first shell and including carbon.
  • the lithium secondary battery to which the anode active material for lithium secondary battery is applied has an initial charge capacity (1,640.8 mAh/g), an initial discharge capacity (1,357 mAh/g), an initial efficiency of 82.7%, and a 50 cycle retention capacity (1,329.9 mAh/g) It can be confirmed that
  • the polymer binder serves as an elastic smart ball with repair ability.
  • anode active material for a lithium secondary battery of the present application surrounds the nanoparticles containing silicon with a polymer binder having a repair ability, the original shape can be maintained even when the nanoparticles expand and contract.
  • FIG. 1 is a view of an anode active material for a lithium secondary battery according to an embodiment of the present application.
  • FIG. 2 is a view of an anode active material for a lithium secondary battery according to an embodiment of the present application.
  • the polymer binder surrounds at least one of the nanoparticles, and the number of the nanoparticles is not limited.
  • the silicon core 111 may be doped with lithium, but is not limited thereto.
  • the lithium-doped silicon core may be represented as SiLi y , and y may be 0.3 to 1.0.
  • the molar ratio of silicon and lithium of the silicon core 111 may be 1:0.2 to 1:2.0, but is not limited thereto.
  • the diameter of the nanoparticles may be 10 nm to 500 ⁇ m, but is not limited thereto.
  • the diameter of the nanoparticles is less than 10 nm, when the silicon content of the core is lowered and used as an anode active material of a lithium secondary battery, the capacity may be lowered. In addition, when the diameter of the nanoparticles exceeds 500 ⁇ m, volume expansion may easily occur when used as an anode active material of a lithium secondary battery.
  • 100 parts by weight of the nanoparticles 1 part by weight to 99 parts by weight of the silicon, and 99 parts by weight to 1 part by weight of the carbon may be included, but is not limited thereto.
  • the thickness of the first shell may be 0.1 nm to 100 nm, but is not limited thereto.
  • the thickness of the shell When the thickness of the shell is less than 0.1 nm, the amount of lithium ions reaching the core increases, but volume expansion easily occurs, so that the efficiency of the electrode may be sharply decreased. In addition, when the thickness of the shell is more than 100 nm, the amount of lithium ions reaching the core may decrease and the capacity contribution may decrease.
  • the thickness of the second shell may be 10 nm to 50 nm, but is not limited thereto.
  • the second shell contains carbon, it has excellent charge/discharge characteristics and a dendrite structure is not generated, so there is a stable advantage.
  • the polymer binder may be one in which two or more polymers are crosslinked and have conductivity and restorative elasticity, but is not limited thereto.
  • the polymer binder is a polymer binder made of a composite binder having a soluble structure and a reversible polymer network.
  • recovery and deformation can be repeated through a morphological change that exhibits high mechanical compatibility with silicon strain.
  • the polymer binder is composed of two or more polymers cross-linked so that expansion and contraction are freely possible, thereby serving as a “smart ball”.
  • the smart ball can help the silicon to shrink to its original shape after expansion when a voltage is applied by applying the negative active material for a lithium secondary battery to a lithium secondary battery.
  • the silicone when the silicone is expanded, it cannot shrink to its original shape and thus may exhibit irreversible characteristics.
  • the present application has applied a smart ball to solve this problem, and since the smart ball is not only expandable but also contracted freely, the characteristics of the lithium secondary battery are reversible, so that the coulombic efficiency, periodicity, charge/discharge rate, lifespan, etc. can be improved.
  • it helps to maintain electrical contact between the core, the first shell, and the second shell it is possible to prevent breakage, detachment, and the like due to excessive expansion.
  • the polymer binder has conductivity, it is possible to improve the efficiency of the lithium secondary battery.
  • the polymer binder can be commercially manufactured at a low cost, so it is easy to reduce the cost of the process.
  • the conventionally used polymer binder is a material used when manufacturing an electrode used in a lithium secondary battery, and only serves to allow the active material, the conductive material, and the current collector to adhere well to each other.
  • the polymer binder includes a polymer selected from the group consisting of polyacrylic acid, polyvinyl alcohol, polyacryl acrylate, polyvinyl acrylic acid, polyamide, polyvinylithene, polyamideimide, polyethylene, polypropylene, and combinations thereof.
  • a polymer selected from the group consisting of polyacrylic acid, polyvinyl alcohol, polyacryl acrylate, polyvinyl acrylic acid, polyamide, polyvinylithene, polyamideimide, polyethylene, polypropylene, and combinations thereof.
  • the present invention is not limited thereto.
  • the polymer may have a concentration of 2 wt% to 50 wt% when water is used as a solvent.
  • the polymer binder may be a smart ball (gel) having a repair ability by chemically crosslinking two or more kinds of water-based binders having a carboxyl group and a hydroxyl group capable of strongly bonding with the silicone.
  • the polymer binder may be at least partially bound to the nanoparticles, but is not limited thereto.
  • the polymer binder may be one in which polyacrylic acid and polyvinyl alcohol are crosslinked, but is not limited thereto.
  • the polyacrylic acid and polyvinyl alcohol are linear polymers, and since they are hydrophilic, water-based (water-soluble) polymers, they may have excellent binding ability with the silicone.
  • the mixing ratio of the polyacrylic acid and polyvinyl alcohol may be 7:3 to 9.5:0.5, but is not limited thereto.
  • the silicon oxide may be SiOx, and x may be 0.1 to 1.6, but is not limited thereto.
  • the silicon may be crystalline or amorphous, but is not limited thereto.
  • a method of manufacturing an anode active material for a lithium secondary battery includes drying silicon core particles; oxidizing the silicon core particles under an oxidizing agent to form a first shell including silicon oxide on the silicon core particles; forming a second shell including carbon on the surface of the first shell by mixing the particles on which the first shell is formed with a carbon source and performing a first heat treatment; preparing a mixture by mixing the particles on which the second shell is formed with a polymer binder; pressurizing and heat-treating the mixture; and pulverizing the pressurized and second heat-treated mixture.
  • the method for producing the negative active material for a lithium secondary battery is a plasma method (gas phase method), a mixed hydrothermal method, a liquid phase method, a temperature rising method, a wet (liquid phase method)/dry method, microwave, CVD, and a method selected from the group consisting of combinations thereof. may be performed.
  • mixing the silicon core particles with a lithium compound may further include, but is not limited thereto.
  • the mixing of the silicon core particles and the lithium compound may include mixing at a temperature of 15°C to 250°C and high-speed mixing under vacuum or mixing under pressure at room temperature, but is not limited thereto.
  • the lithium compound may exist in a liquid or powder form, but is not limited thereto.
  • the high-speed mixing may be performed for 10 to 60 minutes, but is not limited thereto.
  • FIG. 3 is a flowchart of a method of manufacturing a negative active material for a lithium secondary battery according to an embodiment of the present application.
  • the silicon core particles are dried (S100).
  • the drying may include drying the silicon core particles to a moisture content of 1% to 20%, but is not limited thereto.
  • the drying may be performed by heating and oxidizing at a temperature of 180°C to 300°C, but is not limited thereto.
  • the drying step may be dried by a drying method consisting of natural solar drying, oven drying, vacuum freeze drying, atmospheric circulation drying (airflow drying), nitrogen-filled drying, and combinations thereof, but is not limited thereto.
  • the silicon core particles may be destroyed by mutual collision by airflow to be nanosized, but the present invention is not limited thereto.
  • the nanoization process when a physical method is used, mass production is possible, but there is a possibility that contamination may occur and it is difficult to manufacture to a certain size or less.
  • the nanoization process using the airflow has the advantage that low-cost mass production is possible and contamination does not occur.
  • the silicon core particles may be obtained by drying a material selected from the group consisting of SiCl 4 , Si, SiOx, SiO, and combinations thereof, but is not limited thereto.
  • the silicon core particles are oxidized under an oxidizing agent to form a first shell including silicon oxide on the silicon core particles ( S200 ).
  • the oxidizing agent may include an oxidizing agent selected from the group consisting of H 2 O, oxygen, liquid oxygen, hydrogen, and combinations thereof, but is not limited thereto.
  • the oxidizing agent may be liquid oxygen having a purity of 99.9% or more, but is not limited thereto.
  • the oxidizing agent When the oxidizing agent is injected, it may be mixed with air, but is not limited thereto.
  • the input amount of the oxidizing agent may be adjusted according to the input amount of the mixture.
  • the particles on which the first shell is formed are mixed with a carbon source and subjected to a first heat treatment to form a second shell including carbon on the surface of the first shell ( S300 ).
  • the silicon core particles may be finely dispersed while preventing agglomeration. Accordingly, it is possible to prevent the specific surface of the nanoparticles from being reduced and the irreversible capacity from increasing.
  • the carbon source may be selected from the group consisting of graphene, graphite, hard carbon, soft carbon, natural graphite, artificial graphite, pitch, carbon black, carbon nanotubes, and combinations thereof, but is not limited thereto.
  • the carbon source may be a composite of carbon black and pitch, but is not limited thereto.
  • the second shell is formed by contacting the particles on which the first shell is formed through the first heat treatment, and conductivity may be improved due to the carbon of the second shell.
  • the particles on which the second shell is formed are mixed with a polymer binder to prepare a mixture (S400).
  • the polymer binder may be one in which two or more polymers are crosslinked, but is not limited thereto.
  • the crosslinking is polyacrylic acid, polyvinyl alcohol, polyacrylic acid, polyvinyl acrylic acid, polyamide, polyvinylithene, polyamideimide, at least two polymers selected from polyethylene and polypropylene, citric acid, glycerol and liquid copper. It may be made by mixing, but is not limited thereto.
  • the crosslinking may be formed by reacting at a temperature of 30°C to 80°C for 1 hour to 3 hours, but is not limited thereto.
  • the polymer binder is gelled, and it can serve as a smart ball.
  • the mixture may be obtained in the form of a slurry, but is not limited thereto.
  • the size of the slurry may be 1 mm to 10 cm, but is not limited thereto.
  • the slurry may be processed by a process selected from the group consisting of pressurization, molding, drying, grinding, classification, and combinations thereof, but is not limited thereto.
  • the pressurization may be to apply a pressure of 1 ton/cm 2 to 20 ton/cm 2 , but is not limited thereto.
  • the second heat treatment may be performed at a temperature of 100°C to 300°C, but is not limited thereto.
  • the mixture may be molded into a predetermined shape.
  • the shape of the molding is not limited, and may be, for example, a spherical shape, a cylindrical shape, or a hexahedral shape.
  • the molding may be performed by a screw extrusion method or a mold compression method.
  • the spherical shape manufactured by the screw extrusion method may have advantageous mobility and may be effective in drying residual moisture.
  • the molded mixture may further include a step of drying under a temperature of 150° C. to 800° C., but is not limited thereto.
  • the pressurized and second heat-treated mixture is pulverized (S600).
  • the pulverization may be classified as being pulverized by an industrial ball mill or collision by a high-speed air stream, but is not limited thereto.
  • the pulverization may be pulverizing so that the anode active material for a lithium secondary battery has a size of 20 nm to 10 ⁇ m, but is not limited thereto.
  • the size of the negative active material for a lithium secondary battery may be more preferably 5 ⁇ m to 10 ⁇ m, but is not limited thereto.
  • the electrode including the negative electrode active material for the lithium secondary battery can achieve a cost reduction in the process by using inexpensive and commercially available silicon.
  • the present application provides a lithium secondary battery comprising the anode active material for a lithium secondary battery.
  • the lithium secondary battery may include the anode active material for the lithium secondary battery, and thus charge/discharge efficiency and lifespan characteristics may be improved.
  • nanoparticles were prepared by milling and mixing 60 parts by weight of silicon, 58 to 59 parts by weight of carbon black (30-40 nm particles), and 1-2% by weight of citric acid.
  • a mixture of polyvinyl alcohol and polyacrylic acid in a ratio of 1:9 was prepared as a solution having a concentration of 20 wt% (solvent: water).
  • the solution was mixed with citric acid, glycerol, and liquid copper, and then cross-linked at a temperature of 60° C. for 2 hours to prepare a polymer binder.
  • the negative electrode active material slurry for lithium secondary battery prepared in Example 1 and the PVDF conductive binder were added to distilled water, and then uniformly mixed to make a secondary slurry.
  • the secondary slurry was uniformly coated on a copper (Cu) current collector, pressed on a roll press, and dried to prepare a negative electrode.
  • a loading amount of 5 mg/cm 2 was set to have an electrode density of 1.2 to 1.3 g/CC.
  • Li-metal is used as the counter electrode and 1 mol of LiPF 6 in a mixed solvent in which the volume ratio of ethylene carbonate (EC): dimethyl carbonate (DMC) is 1:1 as the electrolyte. A dissolved solution was used.
  • a CR2032 battery (half cell) was prepared according to a conventional manufacturing method using the negative electrode lithium metal and the electrolyte.
  • An anode active material for a lithium secondary battery was prepared in the same manner as in Example 1, except that silicon:carbon black (super P) was mixed in a ratio of 50:50 when preparing the silicon-carbon-based mixture.
  • a lithium secondary battery was manufactured in the same manner as in Preparation Example 1, except that the anode active material for a lithium secondary battery prepared in Comparative Example 1 was used.
  • FIG. 5 is a FIB (focused ion beam) image of the nanoparticles prepared according to the present embodiment.
  • FIG. 6 is a TEM-mapping (transmission electron microscope mapping) image of nanoparticles prepared according to the present embodiment.
  • SEM 7 is a scanning electron microscope (SEM) image of nanoparticles prepared according to the present embodiment.
  • FIG. 9 is a TEM (transmission electron microscope) image of the anode active material for a lithium secondary battery prepared according to the present embodiment.
  • SEM 10 is a scanning electron microscope (SEM) image of an anode active material for a lithium secondary battery manufactured according to this embodiment.
  • FIG. 11 is a view showing the configuration of the secondary battery coin cell according to the present manufacturing example.
  • FIG. 12 is a graph showing the change in capacity according to the cycle of the coin cell of the secondary battery according to the present preparation example.
  • 13 is a graph showing the initial charge/discharge efficiency of the coin cell of the secondary battery according to the present manufacturing example.
  • the tap density was measured by tapping at 3000 cycles @ 284 cycles/min after putting 10 g of powder in a 50 ml container based on ASTM-B527 to measure the packing density.
  • the specific surface area was measured using the BET method (surface area and porosity analyzer), (micromeritices, ASAP2020).
  • the initial charge/discharge capacity and efficiency were tested by applying the negative active material for a lithium secondary battery prepared in Example above to the half battery. Specifically, the battery was driven under the conditions of 0.1C, 5mV, 0.005C cut-off charging and 0.1C, 1.5V cut-off discharge, and initial discharge capacity and initial efficiency were measured.
  • the expansion rate was tested by applying the negative active material for a lithium secondary battery prepared in Example above to the half battery. Specifically, the battery is operated for 1st, 20th, and 50th cycles under the conditions of 0.1C, 5mV, 0.005C cut-off charge and 0.1C, 1.5V cut-off discharge, and the thickness change rate of the electrode measured by disassembling the battery is calculated. measured.
  • Lifespan was measured using the lithium secondary battery (full-cell) prepared in Preparation Example. Specifically, after manufacturing a CR 2032 coin full cell using commercial C.B (carbon black) and synthesized Si-carbon composite negative electrode with a mixed negative electrode capacity of 10 mAh/g and commercial LCO as the positive electrode, 0.5C (charge)/1.0 Long-term lifetime was measured through C (discharge).

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  • Battery Electrode And Active Subsutance (AREA)

Abstract

The present invention was proceeded under the support of the business of (Incorporated Foundation) Gyeongbuk Technopark (business title "Support for Companies of Innovative Business in Regulation-Free Special Zones (business support)", project title "Support for Battery Recycling Business in Regulation-Free Special Zones"). Specifically, the present invention relates to an anode active material for a lithium secondary battery, the anode active material including: nanoparticles; and a polymer binder surrounding at least one of the nanoparticles, wherein the nanoparticles each include: a core containing silicon; a first shell formed on the surface of the core and containing a silicon oxide; and a second shell formed on the surface of the first shell and containing carbon. The nanoparticles having silicon, silicon oxide, and carbon formed in the core-shell structure therein are surrounded by a polymer binder possessing restorative capability according to the present application, thereby preventing the particles from being separated by the expansion and contraction of silicon and enhancing lifespan and charge and discharge characteristics of the secondary battery.

Description

리튬 이차 전지용 음극활물질, 이의 제조 방법 및 이를 포함하는 리튬 이차전지Anode active material for lithium secondary battery, manufacturing method thereof, and lithium secondary battery comprising same
본 발명은 리튬 이차 전지용 음극활물질 및 이의 제조 방법에 관한 것이다. 구체적으로, 실리콘, 실리콘 산화물 및 탄소가 코어-쉘 구조로 형성된 나노입자를 수복 능력(restorative capability)를 갖춘 고분자 바인더가 둘러싸여, 실리콘-탄소-리튬-고분자 바인더의 구성으로 이루어져 있어, 실리콘의 팽창 및 수축에 의한 입자의 탈리를 방지하고 이차전지의 수명을 향상시킬 수 있다.The present invention relates to an anode active material for a lithium secondary battery and a method for manufacturing the same. Specifically, a polymer binder with restorative capability is surrounded by nanoparticles formed in a core-shell structure of silicon, silicon oxide, and carbon, and consists of a silicon-carbon-lithium-polymer binder, so that the expansion and It is possible to prevent detachment of particles due to shrinkage and improve the lifespan of the secondary battery.
전자, 통신, 컴퓨터 산업의 급속한 발전에 따라 캠코더, 휴대폰, 노트북 PC 등이 눈부신 발전을 거듭하고 있으며, 휴대용 전자기기들을 구동할 동력원으로서 배터리의 높은 에너지 밀도와 안정적인 출력이 요구되고 있다. 동시에 생산적인 면에서 저렴하면서 간단한 공정도 요구되고 있다. 이러한 배터리 중에서 리튬 이온 배터리는 가장 활발하게 개발되고 있으며 휴대용 전자 장치에 광범위하게 적용되고 있다. With the rapid development of the electronics, telecommunication and computer industries, camcorders, mobile phones, notebook PCs, etc. are making remarkable progress, and high energy density and stable output of batteries are required as a power source to drive portable electronic devices. At the same time, an inexpensive and simple process in terms of productivity is also required. Among these batteries, the lithium ion battery is most actively developed and is widely applied to portable electronic devices.
실리콘의 이론적 용량은 4,200 mAh/g로 리튬 이온 배터리의 음극에 적용할 수 있는 물질들 중 가장 높다. 실리콘은 높은 출력과 가격이 저렴하다는 장점이 있지만, 리튬 이온의 역삽입과 분리에 의해 상변화가 발생하고, 그로 인해 부피가 300% 이상 팽창하는 문제점이 있다. 이로 인해 실리콘 내부의 응력이 균열을 일으켜 구조가 붕괴되는 현상이 일어나게 된다. 실리콘의 이러한 구조 붕괴는 전극의 전자 전달을 막아 전극 내 사용할 수 없는 공간이 발생하고 그 결과 실리콘의 용량 감소 및 수명의 저하가 일어난다. The theoretical capacity of silicon is 4,200 mAh/g, which is the highest among materials applicable to the negative electrode of a lithium-ion battery. Silicon has advantages of high output and low price, but there is a problem in that a phase change occurs due to the reverse insertion and separation of lithium ions, and thus the volume expands by more than 300%. As a result, the stress inside the silicon causes cracks, which causes the structure to collapse. This structural collapse of the silicon blocks electron transfer in the electrode, resulting in an unusable space in the electrode, resulting in a decrease in the capacity and lifespan of the silicon.
실리콘의 부피 팽창을 억제하기 위해 규화물(Silicide)를 사용할 수 있다. 하지만, 부피 팽창 완화를 위해 금속계 물질을 사용할 경우, 전자 전도도는 높지만 이온 전도도가 떨어져 수명 특성이 저하되는 단점이 있다. Silicide may be used to suppress volume expansion of silicon. However, when a metal-based material is used to relieve volume expansion, there is a disadvantage in that the electronic conductivity is high but the ionic conductivity is lowered, so that the lifespan characteristic is deteriorated.
이에, 금속계 물질 대신 탄소계 물질을 이용하여 실리콘의 부피 팽창을 억제하는 연구가 진행되고 있다. 탄소계 물질은 높은 강도, 높은 이온 및 전자 전도도, 우수한 충, 방전 특성을 가지며, 덴드라이트 구조가 생성되지 않기 때문에 안정적이다. 하지만 상기 흑연의 이론적 충전 용량은 372 mAh/g에 불과하다. 또한, 탄소계 물질을 단순히 코팅하거나 혼합하는 방법으로는 실리콘의 부피팽창을 완충시키기에는 한계가 있다. Accordingly, research on suppressing the volume expansion of silicon by using a carbon-based material instead of a metal-based material is being conducted. Carbon-based materials have high strength, high ionic and electronic conductivity, excellent charge and discharge properties, and are stable because dendrite structures are not formed. However, the theoretical charging capacity of the graphite is only 372 mAh/g. In addition, there is a limit in buffering the volume expansion of silicon by simply coating or mixing the carbon-based material.
[선행기술문헌][Prior art literature]
[특허문헌][Patent Literature]
(특허문헌 0001) 공개특허공보 KR 제10-2017-0120940호(Patent Document 0001) Patent Publication No. KR 10-2017-0120940
본원은 전술한 종래 기술의 문제점을 해결하기 위한 것으로서, 실리콘, 실리콘 산화물 및 탄소가 코어-쉘 구조로 형성된 나노입자를 수복 능력(restorative capability)를 갖춘 고분자 바인더가 둘러싸여 있어, 실리콘의 팽창 및 수축에 의한 입자의 탈리를 방지하고 이차전지의 수명을 향상시키는 효과를 달성하고 있다.The present application is intended to solve the problems of the prior art described above, and a polymer binder with restorative capability is surrounded by nanoparticles formed of silicon, silicon oxide and carbon in a core-shell structure, thereby preventing the expansion and contraction of silicon. It achieves the effect of preventing the detachment of particles due to the effect and improving the lifespan of the secondary battery.
상기한 기술적 과제를 달성하기 위한 본 발명의 리튬이차전지용 음극활물질은 나노 입자; 및 상기 나노 입자를 적어도 하나 이상 둘러싸고 있는 고분자 바인더;를 포함하며, 상기 나노 입자는 실리콘을 포함하는 코어; 상기 코어의 표면 상에 형성되어 있고, 실리콘 산화물을 포함하는 제 1 쉘; 및 상기 제 1 쉘의 표면 상에 형성되어 있고, 탄소를 포함하는 제 2 쉘;을 포함한다. The anode active material for a lithium secondary battery of the present invention for achieving the above technical problem is nanoparticles; and a polymer binder surrounding at least one or more of the nanoparticles, wherein the nanoparticles include: a core including silicon; a first shell formed on the surface of the core and including silicon oxide; and a second shell formed on the surface of the first shell and including carbon.
상기 실리콘 코어는 리튬이 도핑 되어 있는 것 일 수 있으나, 이에 제한되는 것은 아니다. The silicon core may be doped with lithium, but is not limited thereto.
상기 나노 입자의 직경은 10 nm 내지 500 μm인 것 일 수 있으나, 이에 제한되는 것은 아니다. The diameter of the nanoparticles may be 10 nm to 500 μm, but is not limited thereto.
상기 제 1 쉘의 두께는 0.1 nm 내지 100 nm인 것 일 수 있으나, 이에 제한되는 것은 아니다. The thickness of the first shell may be 0.1 nm to 100 nm, but is not limited thereto.
상기 제 2 쉘의 두께는 10 nm 내지 50 nm인 것 일 수 있으나, 이에 제한되는 것은 아니다. The thickness of the second shell may be 10 nm to 50 nm, but is not limited thereto.
상기 고분자 바인더는 두 개 이상의 고분자가 가교 결합으로 이루어져 있으며, 전도성 및 수복 탄성을 가지는 것 일 수 있으나, 이에 제한되는 것은 아니다. The polymer binder may be one in which two or more polymers are crosslinked and have conductivity and restorative elasticity, but is not limited thereto.
상기 고분자 바인더는 폴리아크릴산, 폴리비닐알콜, 폴리비닐아크릴산, 폴리아마이드, 폴리비닐리텐, 폴리아미드이미드, 폴리에틸렌, 폴리프로필렌 및 이들의 조합들로 이루어진 군에서 선택된 고분자를 포함하는 것 일 수 있으나, 이에 제한되는 것은 아니다. The polymer binder may include a polymer selected from the group consisting of polyacrylic acid, polyvinyl alcohol, polyvinyl acrylic acid, polyamide, polyvinylithene, polyamideimide, polyethylene, polypropylene, and combinations thereof. It is not limited.
상기 고분자 바인더는 폴리아크릴산 및 폴리비닐알콜이 가교결합으로 이루어져 있는 것 일 수 있으나, 이에 제한되는 것은 아니다.The polymer binder may be one in which polyacrylic acid and polyvinyl alcohol are crosslinked, but is not limited thereto.
상기 실리콘 산화물은 SiO x이며, 상기 x는 0.1 내지 1.6인 것 일 수 있으나, 이에 제한되는 것은 아니다. The silicon oxide may be SiO x , and x may be 0.1 to 1.6, but is not limited thereto.
상기 실리콘은 정질 또는 비정질인 것 일 수 있으나, 이에 제한되는 것은 아니다. The silicon may be crystalline or amorphous, but is not limited thereto.
리튬이차전지용 음극활물질의 제조 방법은 실리콘 코어 입자를 건조하는 단계; 상기 실리콘 코어 입자를 산화제 하에서 산화시켜 상기 실리콘 코어 입자 상에 실리콘 산화물을 포함하는 제 1 쉘을 형성하는 단계; 상기 제 1 쉘이 형성된 입자를 탄소 소스와 혼합 및 제 1 열처리하여 상기 제 1 쉘의 표면 상에 탄소를 포함하는 제 2 쉘을 형성하는 단계; 상기 제 2 쉘이 형성된 입자를 고분자 바인더와 혼합하여 혼합물을 제조하는 단계; 상기 혼합물을 가압 및 열처리하는 단계; 및 상기 가압 및 제 2 열처리된 혼합물을 분쇄하는 단계;를 포함한다. A method of manufacturing an anode active material for a lithium secondary battery includes drying silicon core particles; oxidizing the silicon core particles under an oxidizing agent to form a first shell including silicon oxide on the silicon core particles; forming a second shell including carbon on the surface of the first shell by mixing the particles on which the first shell is formed with a carbon source and performing a first heat treatment; preparing a mixture by mixing the particles on which the second shell is formed with a polymer binder; pressurizing and heat-treating the mixture; and pulverizing the pressurized and second heat-treated mixture.
건조하는 단계 이전에, 상기 실리콘 코어 입자를 리튬 화합물과 혼합하는 단계;를 더 포함하는 것 일 수 있으나, 이에 제한되는 것은 아니다. Before the drying step, mixing the silicon core particles with a lithium compound; may further include, but is not limited thereto.
상기 리튬 화합물은 리튬하이드록사이드 또는 리튬카보네이트인 것 일 수 있으나, 이에 제한되는 것은 아니다. The lithium compound may be lithium hydroxide or lithium carbonate, but is not limited thereto.
상기 건조하는 단계는 상기 실리콘 코어 입자의 수분이 1% 내지 20%로 건조하는 것 일 수 있으나, 이에 제한되는 것은 아니다. The drying may include drying the silicon core particles to a moisture content of 1% to 20%, but is not limited thereto.
상기 고분자 바인더는 두 개 이상의 고분자가 가교 결합으로 이루어져 있는 것 일 수 있으나, 이에 제한되는 것은 아니다. The polymer binder may be one in which two or more polymers are crosslinked, but is not limited thereto.
상기 가교 결합은 폴리아크릴산, 폴리비닐알콜, 폴리아크릴아케이트, 폴리비닐아크릴산, 폴리아마이드, 폴리비닐리텐, 폴리아미드이미드, 폴리에틸렌 및 폴리프로필렌 중에서 선택된 두 개 이상의 고분자, 시트르산, 글리세롤 및 액상 구리를 혼합하여 이루어지는 것 일 수 있으나, 이에 제한되는 것은 아니다. The crosslinking is performed by mixing two or more polymers selected from polyacrylic acid, polyvinyl alcohol, polyacryl acrylate, polyvinyl acrylic acid, polyamide, polyvinylithene, polyamideimide, polyethylene and polypropylene, citric acid, glycerol and liquid copper. It may be done, but is not limited thereto.
상기 가교 결합은 30℃내지 80℃의 온도에서 1 시간 내지 3 시간동안 반응시켜 이루어지는 것 일 수 있으나, 이에 제한되는 것은 아니다. The crosslinking may be formed by reacting at a temperature of 30°C to 80°C for 1 hour to 3 hours, but is not limited thereto.
상기 가압은 1 ton/cm 2 내지 20 ton/cm 2의 압력을 가하는 것 일 수 있으나, 이에 제한되는 것은 아니다. The pressurization may be to apply a pressure of 1 ton/cm 2 to 20 ton/cm 2 , but is not limited thereto.
상기 제 2 열처리는 150℃내지 800℃의 온도에서 이루어지는 것 일 수 있으나, 이에 제한되는 것은 아니다. The second heat treatment may be performed at a temperature of 150°C to 800°C, but is not limited thereto.
상기 탄소 소스는 그래핀, 그래파이트, 하드카본, 소프트카본, 천연 흑연, 인조흑연, 피치, 카본블랙 및 이들의 조합들로 이루어진 군에서 선택된 것 일 수 있으나, 이에 제한되는 것은 아니다. The carbon source may be selected from the group consisting of graphene, graphite, hard carbon, soft carbon, natural graphite, artificial graphite, pitch, carbon black, and combinations thereof, but is not limited thereto.
리튬 이차전지는 상기 리튬이차전지용 음극활물질을 포함한다. The lithium secondary battery includes the anode active material for the lithium secondary battery.
상술한 과제 해결 수단은 단지 예시적인 것으로서, 본원을 제한하려는 의도로 해석되지 않아야 한다. 상술한 예시적인 실시예 외에도, 도면 및 발명의 상세한 설명에 추가적인 실시예가 존재할 수 있다.The above-described problem solving means are merely exemplary, and should not be construed as limiting the present application. In addition to the exemplary embodiments described above, additional embodiments may exist in the drawings and detailed description.
개시된 기술은 다음의 효과를 가질 수 있다. 다만, 특정 실시예가 다음의 효과를 전부 포함하여야 한다 거나 다음의 효과만을 포함하여야 한다는 의미는 아니므로, 개시된 기술의 권리범위는 이에 의하여 제한되는 것으로 이해되어서는 아니 될 것이다.The disclosed technology may have the following effects. However, this does not mean that a specific embodiment should include all of the following effects or only the following effects, so the scope of the disclosed technology should not be construed as being limited thereby.
전술한 본원의 과제 해결 수단에 의하면, 본원에 따른 고분자 바인더는 두 개 이상의 고분자가 가교 결합으로 이루어져 있어 팽창 및 수축이 자유롭게 가능하여 "스마트 볼"역할을 할 수 있다. 상기 스마트 볼은 상기 리튬이차전지용 음극활물질을 리튬이차전지에 적용하고, 전압을 인가하였을 때, 상기 실리콘이 팽창 후 원래의 모습으로 수축하는 데에 도움을 줄 수 있다. 상기 스마트 볼은 팽창뿐만 아니라 수축 또한 자유롭기 때문에 리튬이차전지의 특성이 가역적으로 나타나 쿨롱 효율 주기성, 충방전 속도, 수명 등이 향상될 수 있다. 또한, 상기 코어, 제 1 쉘 및 제 2 쉘의 전기적 접촉을 유지하도록 돕기 때문에 과도한 팽창으로 인한 파괴, 탈리 등을 방지할 수 있다.According to the above-described problem solving means of the present application, the polymer binder according to the present application is made of two or more polymers cross-linked, so that expansion and contraction are freely possible, so that it can serve as a "smart ball". The smart ball can help the silicon to shrink to its original shape after expansion when the negative active material for the lithium secondary battery is applied to the lithium secondary battery and voltage is applied. Since the smart ball is not only expandable but also contracted freely, the characteristics of the lithium secondary battery are reversible, so that the coulombic efficiency, periodicity, charge/discharge rate, lifespan, etc. can be improved. In addition, since it helps to maintain electrical contact between the core, the first shell, and the second shell, it is possible to prevent breakage, detachment, and the like due to excessive expansion.
도 1은 본원의 일 구현예에 따른 리튬이차전지용 음극활물질의 도면이다. 1 is a view of an anode active material for a lithium secondary battery according to an embodiment of the present application.
도 2는 본원의 일 구현예에 따른 리튬이차전지용 음극활물질의 도면이다.2 is a view of an anode active material for a lithium secondary battery according to an embodiment of the present application.
도 3은 본원의 일 구현예에 따른 리튬이차전지용 음극활물질의 제조 방법의 순서도이다.3 is a flowchart of a method of manufacturing a negative active material for a lithium secondary battery according to an embodiment of the present application.
도 4는 본 실시예에 따라 제조된 나노 입자의 TEM (transmission electron microscope) 이미지이다.4 is a TEM (transmission electron microscope) image of nanoparticles prepared according to the present embodiment.
도 5는 본 실시예에 따라 제조된 나노 입자의 FIB (focused ion beam) 이미지이다.5 is a FIB (focused ion beam) image of the nanoparticles prepared according to the present embodiment.
도 6은 본 실시예에 따라 제조된 나노 입자의 TEM-mapping (transmission electron microscope mapping) 이미지이다.6 is a TEM-mapping (transmission electron microscope mapping) image of nanoparticles prepared according to the present embodiment.
도 7은 본 실시예에 따라 제조된 나노 입자의 SEM (scanning electron microscope) 이미지이다.7 is a scanning electron microscope (SEM) image of nanoparticles prepared according to the present embodiment.
도 8의 (a) 내지 (d)는 본 실시예에 따라 제조된 나노 입자의 TEM-mapping (transmission electron microscope mapping) 이미지이다.8A to 8D are transmission electron microscope mapping (TEM-mapping) images of nanoparticles prepared according to the present embodiment.
도 9는 본 실시예에 따라 제조된 리튬이차전지용 음극활물질의 TEM (transmission electron microscope) 이미지이다. 9 is a TEM (transmission electron microscope) image of the anode active material for a lithium secondary battery prepared according to the present embodiment.
도 10은 본 실시예에 따라 제조된 리튬이차전지용 음극활물질의 SEM(scanning electron microscope) 이미지이다.10 is a scanning electron microscope (SEM) image of an anode active material for a lithium secondary battery manufactured according to this embodiment.
도 11은 본 제조예에 따른 이차전지 코인셀의 구성을 나타낸 도면이다. 11 is a view showing the configuration of the secondary battery coin cell according to the present manufacturing example.
도 12은 본 제조예에 따른 이차전지 코인셀의 사이클에 따른 용량 변화를 나타낸 그래프이다. 12 is a graph showing the change in capacity according to the cycle of the coin cell of the secondary battery according to the present preparation example.
도 13는 본 제조예에 따른 이차전지 코인셀의 사이클에 따른 용량 유지율 변화를 나타낸 그래프이다.13 is a graph showing the change in capacity retention rate according to the cycle of the coin cell of the secondary battery according to the present preparation example.
본 발명은 다양한 변경을 가할 수 있고 여러 가지 실시예를 가질 수 있는 바, 특정 실시예들을 도면에 예시하고 상세한 설명에 구체적으로 설명하고자 한다. 그러나 이는 본 발명을 특정한 실시 형태에 대해 한정하려는 것이 아니며, 본 발명의 사상 및 기술 범위에 포함되는 모든 변경, 균등물 내지 대체물을 포함하는 것으로 이해되어야 한다.Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and will be described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.
각 도면을 설명하면서 유사한 참조부호를 유사한 구성요소에 대해 사용한다. 제 1, 제 2등의 용어는 다양한 구성요소들을 설명하는데 사용될 수 있지만, 상기 구성요소들은 상기 용어들에 의해 한정되어서는 안 된다. 상기 용어들은 하나의 구성요소를 다른 구성요소로부터 구별하는 목적으로만 사용된다.In describing each figure, like reference numerals are used for like elements. Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.
예를 들어, 본 발명의 권리 범위를 벗어나지 않으면서 제 1 구성요소는 제 2 구성요소로 명명될 수 있고, 유사하게 제 2 구성요소도 제 1 구성요소로 명명될 수 있다. "및/또는" 이라는 용어는 복수의 관련된 기재된 항목들의 조합 또는 복수의 관련된 기재된 항목들 중의 어느 항목을 포함한다. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. The term “and/or” includes a combination of a plurality of related listed items or any of a plurality of related listed items.
다르게 정의되지 않는 한, 기술적이거나 과학적인 용어를 포함해서 여기서 사용되는 모든 용어들은 본 발명이 속하는 기술 분야에서 통상의 지식을 가진 자에 의해 일반적으로 이해되는 것과 동일한 의미가 있다. Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
일반적으로 사용되는 사전에 정의되어 있는 것과 같은 용어들은 관련 기술의 문맥상 가지는 의미와 일치하는 의미가 있는 것으로 해석되어야 하며, 본 출원에서 명백하게 정의하지 않는 한, 이상적이거나 과도하게 형식적인 의미로 해석되지 않아야 한다. Terms such as those defined in commonly used dictionaries should be interpreted as having meanings consistent with the meanings in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. shouldn't
본원 명세서 전체에서, 어떤 부재가 다른 부재 "상에", "상부에", "상단에", "하에", "하부에", "하단에" 위치하고 있다고 할 때, 이는 어떤 부재가 다른 부재에 접해 있는 경우뿐 아니라 두 부재 사이에 또 다른 부재가 존재하는 경우도 포함한다.Throughout this specification, when a member is positioned “on”, “on”, “on”, “on”, “under”, “under”, or “under” another member, this means that a member is positioned on the other member. It includes not only the case where they are in contact, but also the case where another member exists between two members.
본원 명세서 전체에서, 어떤 부분이 어떤 구성요소를 "포함" 한다고 할 때, 이는 특별히 반대되는 기재가 없는 한 다른 구성요소를 제외하는 것이 아니라 다른 구성 요소를 더 포함할 수 있는 것을 의미한다.Throughout this specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.
본 명세서에서 사용되는 정도의 용어 "약", "실질적으로" 등은 언급된 의미에 고유한 제조 및 물질 허용오차가 제시될 때 그 수치에서 또는 그 수치에 근접한 의미로 사용되고, 본원의 이해를 돕기 위해 정확하거나 절대적인 수치가 언급된 개시 내용을 비양심적인 침해자가 부당하게 이용하는 것을 방지하기 위해 사용된다. 또한, 본원 명세서 전체에서, "~ 하는 단계" 또는 "~의 단계"는 "~를 위한 단계"를 의미하지 않는다. As used herein, the terms "about," "substantially," and the like are used in a sense at or close to the numerical value when the manufacturing and material tolerances inherent in the stated meaning are presented, and to aid in the understanding of the present application. It is used to prevent an unconscionable infringer from using the mentioned disclosure in an unreasonable way. Also, throughout this specification, "step to" or "step to" does not mean "step for".
본원 명세서 전체에서, 마쿠시 형식의 표현에 포함된 "이들의 조합"의 용어는 마쿠시 형식의 표현에 기재된 구성 요소들로 이루어진 군에서 선택되는 하나 이상의 혼합 또는 조합을 의미하는 것으로서, 상기 구성 요소들로 이루어진 군에서 선택되는 하나 이상을 포함하는 것을 의미한다.Throughout this specification, the term "combination of these" included in the expression of the Markush form means one or more mixtures or combinations selected from the group consisting of the components described in the expression of the Markush form, and the components It is meant to include one or more selected from the group consisting of.
이하에서는 본원의 리튬이차전지용 음극활물질 및 이의 제조방법에 대하여 구현 예 및 실시예와 도면을 참조하여 구체적으로 설명하도록 한다. 그러나, 본원이 이러한 구현 예 및 실시예와 도면에 제한되는 것은 아니다.Hereinafter, the negative active material for a lithium secondary battery of the present application and a method for manufacturing the same will be described in detail with reference to embodiments and examples and drawings. However, the present application is not limited to these embodiments and examples and drawings.
본원은, 나노 입자; 및 상기 나노 입자를 적어도 하나 이상 둘러싸고 있는 고분자 바인더;를 포함하며, 상기 나노 입자는 실리콘을 포함하는 코어; 상기 코어의 표면 상에 형성되어 있고, 실리콘 산화물을 포함하는 제 1 쉘; 및 상기 제 1 쉘의 표면 상에 형성되어 있고, 탄소를 포함하는 제 2 쉘;을 포함하는 리튬이차전지용 음극활물질에 관한 것이다. The present application, nanoparticles; and a polymer binder surrounding at least one or more of the nanoparticles, wherein the nanoparticles include: a core including silicon; a first shell formed on the surface of the core and including silicon oxide; and a second shell formed on the surface of the first shell and including carbon.
상기 리튬이차전지용 음극활물질을 적용한 리튬이차전지는 초기 충전용량 (1,640.8 mAh/g), 초기 방전용량(1,357 mAh/g), 초기효율 82.7% 및 50 싸이클(cycle) 유지 용량(1,329.9 mAh/g)인 것을 확인할 수 있다. The lithium secondary battery to which the anode active material for lithium secondary battery is applied has an initial charge capacity (1,640.8 mAh/g), an initial discharge capacity (1,357 mAh/g), an initial efficiency of 82.7%, and a 50 cycle retention capacity (1,329.9 mAh/g) It can be confirmed that
상기 고분자 바인더는 수복 능력을 갖춘 탄성 스마트 볼(smart ball)역할을 한다. The polymer binder serves as an elastic smart ball with repair ability.
종래에 실리콘 음극 활물질의 부피 팽창을 줄이기 위해 미분화(나노화) 기술 연구가 진행되어 절대 팽창율이 줄어들고 수명 특성이 향상되었으나, 나노화된 실리콘 입자가 응집되어 비가역 용량이 증가하는 문제점이 있다. 본원의 리튬이차전지용 음극활물질은 실리콘을 포함하는 나노입자를 수복 능력을 갖춘 고분자 바인더가 둘러싸고 있기 때문에 상기 나노입자의 팽창 및 수축에도 원형을 유지할 수 있다. Conventionally, research on micronization (nanoization) technology has been conducted to reduce the volume expansion of the silicon anode active material, so that the absolute expansion rate is reduced and the lifespan characteristics are improved. Since the anode active material for a lithium secondary battery of the present application surrounds the nanoparticles containing silicon with a polymer binder having a repair ability, the original shape can be maintained even when the nanoparticles expand and contract.
도 1은 본원의 일 구현예에 따른 리튬이차전지용 음극활물질의 도면이다. 1 is a view of an anode active material for a lithium secondary battery according to an embodiment of the present application.
도 2는 본원의 일 구현예에 따른 리튬이차전지용 음극활물질의 도면이다.2 is a view of an anode active material for a lithium secondary battery according to an embodiment of the present application.
도 2를 참조하면, 상기 고분자 바인더는 상기 나노 입자를 적어도 하나 이상 둘러싸고 있으며, 상기 나노 입자의 개수는 제한되지 않는다. Referring to FIG. 2 , the polymer binder surrounds at least one of the nanoparticles, and the number of the nanoparticles is not limited.
상기 실리콘 코어(111)는 리튬이 도핑되어 있는 것 일 수 있으나, 이에 제한되는 것은 아니다. The silicon core 111 may be doped with lithium, but is not limited thereto.
상기 리튬이 도핑된 실리콘 코어는 SiLi y로서 나타낼 수 있으며, 상기 y는 0.3 내지 1.0인 것 일 수 있다. The lithium-doped silicon core may be represented as SiLi y , and y may be 0.3 to 1.0.
상기 실리콘 코어(111)의 실리콘과 리튬의 몰비는 1:0.2 내지 1:2.0인 것 일 수 있으나, 이에 제한되는 것은 아니다. The molar ratio of silicon and lithium of the silicon core 111 may be 1:0.2 to 1:2.0, but is not limited thereto.
상기 나노 입자의 직경은 10 nm 내지 500 μm인 것 일 수 있으나, 이에 제한되는 것은 아니다. The diameter of the nanoparticles may be 10 nm to 500 μm, but is not limited thereto.
나노 입자의 직경이 10 nm 미만일 경우, 상기 코어의 실리콘의 함량이 낮아지면서 리튬 이차전지의 음극 활물질로서 활용할 때, 용량이 낮아질 수 있다. 또한, 상기 나노 입자의 직경이 500 μm 초과일 경우 리튬 이차전지의 음극 활물질로서 활용할 때 부피팽창이 쉽게 일어날 수 있다.When the diameter of the nanoparticles is less than 10 nm, when the silicon content of the core is lowered and used as an anode active material of a lithium secondary battery, the capacity may be lowered. In addition, when the diameter of the nanoparticles exceeds 500 μm, volume expansion may easily occur when used as an anode active material of a lithium secondary battery.
상기 나노 입자 100 중량부에 있어서, 상기 실리콘은 1 중량부 내지 99 중량부, 상기 탄소는 99 중량부 내지 1 중량부로 포함되는 것 일 수 있으나, 이에 제한되는 것은 아니다. In 100 parts by weight of the nanoparticles, 1 part by weight to 99 parts by weight of the silicon, and 99 parts by weight to 1 part by weight of the carbon may be included, but is not limited thereto.
상기 제 1 쉘의 두께는 0.1 nm 내지 100 nm인 것 일 수 있으나, 이에 제한되는 것은 아니다. The thickness of the first shell may be 0.1 nm to 100 nm, but is not limited thereto.
상기 쉘의 두께가 0.1 nm 미만인 경우, 상기 코어까지 도달하는 리튬이온의 양이 증가하지만 부피 팽창이 쉽게 일어나 전극의 효율이 급격히 떨어질 수 있다. 또한, 상기 쉘의 두께가 100 nm 초과인 경우 상기 코어까지 도달하는 리튬이온의 양이 적어지면서 용량 기여도가 낮아지게 될 수 있다.When the thickness of the shell is less than 0.1 nm, the amount of lithium ions reaching the core increases, but volume expansion easily occurs, so that the efficiency of the electrode may be sharply decreased. In addition, when the thickness of the shell is more than 100 nm, the amount of lithium ions reaching the core may decrease and the capacity contribution may decrease.
상기 제 2 쉘의 두께는 10 nm 내지 50 nm인 것 일 수 있으나, 이에 제한되는 것은 아니다. The thickness of the second shell may be 10 nm to 50 nm, but is not limited thereto.
상기 제 2 쉘이 탄소를 포함함으로써 우수한 충방전 특성을 가지며 덴드라이트 구조가 생성되지 않기 때문에 안정적인 장점이 있다.Since the second shell contains carbon, it has excellent charge/discharge characteristics and a dendrite structure is not generated, so there is a stable advantage.
상기 고분자 바인더는 두 개 이상의 고분자가 가교 결합으로 이루어져 있으며, 전도성 및 수복 탄성을 가지는 것 일 수 있으나, 이에 제한되는 것은 아니다. The polymer binder may be one in which two or more polymers are crosslinked and have conductivity and restorative elasticity, but is not limited thereto.
상기 고분자 바인더는 가용성 구조를 가지고 가역적 고분자 네트워크로 된 복합 바인더에 의해 만들어진 고분자 바인더이다. 또한, 실리콘 변형(Strain)에 대한 높은 기계적 적합성을 나타내는 모폴로지 변화를 통해 회복 및 변형을 반복할 수 있다. The polymer binder is a polymer binder made of a composite binder having a soluble structure and a reversible polymer network. In addition, recovery and deformation can be repeated through a morphological change that exhibits high mechanical compatibility with silicon strain.
상기 고분자 바인더는 두 개 이상의 고분자가 가교 결합으로 이루어져 있어 팽창 및 수축이 자유롭게 가능하여 "스마트 볼"역할을 할 수 있다. The polymer binder is composed of two or more polymers cross-linked so that expansion and contraction are freely possible, thereby serving as a “smart ball”.
상기 스마트 볼은 상기 리튬이차전지용 음극활물질을 리튬이차전지에 적용하고, 전압을 인가하였을 때, 상기 실리콘이 팽창 후 원래의 모습으로 수축하는 데에 도움을 줄 수 있다. 종래에는 리튬이차전지에 사용되는 실리콘의 팽창을 억제하는 연구만을 진행해왔다. 다만, 이 경우에는 실리콘이 팽창되었을 때에 원래의 모습으로 수축하지 못하여 비가역적인 특성을 나타낼 수 있다. 본원은 이러한 문제점을 해결하기 위해 스마트 볼을 적용하였으며, 상기 스마트 볼은 팽창뿐만 아니라 수축 또한 자유롭기 때문에 리튬이차전지의 특성이 가역적으로 나타나 쿨롱 효율 주기성, 충방전 속도, 수명 등이 향상될 수 있다. 또한, 상기 코어, 제 1 쉘 및 제 2 쉘의 전기적 접촉을 유지하도록 돕기 때문에 과도한 팽창으로 인한 파괴, 탈리 등을 방지할 수 있다. The smart ball can help the silicon to shrink to its original shape after expansion when a voltage is applied by applying the negative active material for a lithium secondary battery to a lithium secondary battery. Conventionally, only research has been conducted to suppress the expansion of silicon used in lithium secondary batteries. However, in this case, when the silicone is expanded, it cannot shrink to its original shape and thus may exhibit irreversible characteristics. The present application has applied a smart ball to solve this problem, and since the smart ball is not only expandable but also contracted freely, the characteristics of the lithium secondary battery are reversible, so that the coulombic efficiency, periodicity, charge/discharge rate, lifespan, etc. can be improved. In addition, since it helps to maintain electrical contact between the core, the first shell, and the second shell, it is possible to prevent breakage, detachment, and the like due to excessive expansion.
나아가, 상기 고분자 바인더는 전도성을 가지기 때문에 리튬이차전지의 효율을 향상시킬 수 있다. Furthermore, since the polymer binder has conductivity, it is possible to improve the efficiency of the lithium secondary battery.
또한, 상기 고분자 바인더는 상업적으로 저렴한 비용으로 제조가 가능하여 공정의 저가화에 용이하다. In addition, the polymer binder can be commercially manufactured at a low cost, so it is easy to reduce the cost of the process.
더욱이, 종래에 사용되는 고분자 바인더는 리튬이차전지에서 사용되는 전극을 제작할 때 사용되는 물질로서, 활물질, 도전재 및 집전체가 서로 잘 붙어 있을 수 있는 역할만을 했을 뿐이다. Moreover, the conventionally used polymer binder is a material used when manufacturing an electrode used in a lithium secondary battery, and only serves to allow the active material, the conductive material, and the current collector to adhere well to each other.
상기 고분자 바인더는 폴리아크릴산, 폴리비닐알콜, 폴리아크릴아케이트, 폴리비닐아크릴산, 폴리아마이드, 폴리비닐리텐, 폴리아미드이미드, 폴리에틸렌, 폴리프로필렌 및 이들의 조합들로 이루어진 군에서 선택된 고분자를 포함하는 것 일 수 있으나, 이에 제한되는 것은 아니다. The polymer binder includes a polymer selected from the group consisting of polyacrylic acid, polyvinyl alcohol, polyacryl acrylate, polyvinyl acrylic acid, polyamide, polyvinylithene, polyamideimide, polyethylene, polypropylene, and combinations thereof. However, the present invention is not limited thereto.
상기 고분자는 물을 용매로 사용했을 때 2wt% 내지 50wt% 농도인 것 일 수 있다. The polymer may have a concentration of 2 wt% to 50 wt% when water is used as a solvent.
상기 고분자 바인더는 상기 실리콘과 강하게 결합할 수 있는 카르복시기 및 하이드록시기를 가지는 두 종류 이상의 수계 바인더를 화학적으로 가교 시켜 수복 능력을 가지는 스마트 볼(겔)이 될 수 있다. The polymer binder may be a smart ball (gel) having a repair ability by chemically crosslinking two or more kinds of water-based binders having a carboxyl group and a hydroxyl group capable of strongly bonding with the silicone.
상기 고분자 바인더는 상기 나노입자에 적어도 일부분 결합되어 있는 것 일 수 있으나, 이에 제한되는 것은 아니다. The polymer binder may be at least partially bound to the nanoparticles, but is not limited thereto.
상기 고분자 바인더는 폴리아크릴산 및 폴리비닐알콜이 가교결합으로 이루어져 있는 것 일 수 있으나, 이에 제한되는 것은 아니다.The polymer binder may be one in which polyacrylic acid and polyvinyl alcohol are crosslinked, but is not limited thereto.
상기 폴리아크릴산 및 폴리비닐알콜은 선형 고분자로서, 친수성인 수계(수용성) 고분자이기 때문에 상기 실리콘과 우수한 결착 능력을 가질 수 있다. The polyacrylic acid and polyvinyl alcohol are linear polymers, and since they are hydrophilic, water-based (water-soluble) polymers, they may have excellent binding ability with the silicone.
상기 폴리아크릴산 및 폴리비닐알콜의 혼합비는 7:3 내지 9.5:0.5인 것일 수 있으나, 이에 제한되는 것은 아니다. The mixing ratio of the polyacrylic acid and polyvinyl alcohol may be 7:3 to 9.5:0.5, but is not limited thereto.
상기 실리콘 산화물은 SiOx이며, 상기 x는 0.1 내지 1.6인 것 일 수 있으나, 이에 제한되는 것은 아니다. The silicon oxide may be SiOx, and x may be 0.1 to 1.6, but is not limited thereto.
상기 실리콘 산화물 (SiO x)의 x가 0.1 미만인 경우 코어의 부피팽창이 일어날 시 완충작용 효과가 떨어져 전극의 효율이 저하되는 문제가 발생할 수 있다. 또한, 상기 x가 2.0이 되는 경우 상기 실리콘 산화물은 SiO 2가 됨으로써 전기전도 성질 및 이론 용량이 낮아지는(SiO 2의 이론용량=1,965 mAh/g, Si의 이론 용량=4,200 mAh/g)문제가 발생할 수 있다. 또한, 충방전 시 보다 안정적인 용량 유지율을 확보할 수 있다.When x of the silicon oxide (SiO x ) is less than 0.1, when the volume expansion of the core occurs, the buffering effect is reduced and the efficiency of the electrode is lowered. In addition, when x is 2.0, the silicon oxide becomes SiO 2 , thereby lowering electrical conductivity and theoretical capacity (theoretical capacity of SiO 2 = 1,965 mAh/g, theoretical capacity of Si = 4,200 mAh/g). can occur In addition, it is possible to secure a more stable capacity retention rate during charging and discharging.
상기 실리콘은 정질 또는 비정질인 것 일 수 있으나, 이에 제한되는 것은 아니다. The silicon may be crystalline or amorphous, but is not limited thereto.
리튬이차전지용 음극활물질의 제조 방법은 실리콘 코어 입자를 건조하는 단계; 상기 실리콘 코어 입자를 산화제 하에서 산화시켜 상기 실리콘 코어 입자 상에 실리콘 산화물을 포함하는 제 1 쉘을 형성하는 단계; 상기 제 1 쉘이 형성된 입자를 탄소 소스와 혼합 및 제 1 열처리하여 상기 제 1 쉘의 표면 상에 탄소를 포함하는 제 2 쉘을 형성하는 단계; 상기 제 2 쉘이 형성된 입자를 고분자 바인더와 혼합하여 혼합물을 제조하는 단계; 상기 혼합물을 가압 및 열처리하는 단계; 및 상기 가압 및 제 2 열처리된 혼합물을 분쇄하는 단계;를 포함한다. A method of manufacturing an anode active material for a lithium secondary battery includes drying silicon core particles; oxidizing the silicon core particles under an oxidizing agent to form a first shell including silicon oxide on the silicon core particles; forming a second shell including carbon on the surface of the first shell by mixing the particles on which the first shell is formed with a carbon source and performing a first heat treatment; preparing a mixture by mixing the particles on which the second shell is formed with a polymer binder; pressurizing and heat-treating the mixture; and pulverizing the pressurized and second heat-treated mixture.
상기 리튬이차전지용 음극활물질의 제조 방법은 플라즈마법(기상법), 혼합 수열법, 액상법, 승온법, 습식(액상법)·건식방법, 마이크로웨이브, CVD 및 이들의 조합들로 이루어진 군에서 선택된 방법에 의해 수행되는 것 일 수 있다. The method for producing the negative active material for a lithium secondary battery is a plasma method (gas phase method), a mixed hydrothermal method, a liquid phase method, a temperature rising method, a wet (liquid phase method)/dry method, microwave, CVD, and a method selected from the group consisting of combinations thereof. may be performed.
건조하는 단계 이전에, 상기 실리콘 코어 입자를 리튬 화합물과 혼합하는 단계;를 더 포함하는 것 일 수 있으나, 이에 제한되는 것은 아니다. Before the drying step, mixing the silicon core particles with a lithium compound; may further include, but is not limited thereto.
상기 실리콘 코어 입자와 상기 리튬 화합물을 혼합하는 단계는 15℃ 내지 250℃의 온도 및 진공 하에서 고속 믹싱 또는 상온에서 가압 믹싱으로 혼합되는 것 일 수 있으나, 이에 제한되는 것은 아니다. The mixing of the silicon core particles and the lithium compound may include mixing at a temperature of 15°C to 250°C and high-speed mixing under vacuum or mixing under pressure at room temperature, but is not limited thereto.
상기 리튬 화합물은 액상 또는 분말로 존재하는 것 일 수 있으나, 이에 제한되는 것은 아니다. The lithium compound may exist in a liquid or powder form, but is not limited thereto.
상기 고속 믹싱은 10 분 내지 60분동안 이루어지는 것 일 수 있으나, 이에 제한되는 것은 아니다. The high-speed mixing may be performed for 10 to 60 minutes, but is not limited thereto.
도 3은 본원의 일 구현예에 따른 리튬이차전지용 음극활물질의 제조 방법의 순서도이다. 3 is a flowchart of a method of manufacturing a negative active material for a lithium secondary battery according to an embodiment of the present application.
먼저, 실리콘 코어 입자를 건조한다(S100). First, the silicon core particles are dried (S100).
상기 건조하는 단계는 상기 실리콘 코어 입자의 수분이 1% 내지 20%로 건조하는 것 일 수 있으나, 이에 제한되는 것은 아니다. The drying may include drying the silicon core particles to a moisture content of 1% to 20%, but is not limited thereto.
상기 건조하는 단계는 180℃ 내지 300℃의 온도에서 가열 산화하여 이루어지는 것 일 수 있으나, 이에 제한되는 것은 아니다. The drying may be performed by heating and oxidizing at a temperature of 180°C to 300°C, but is not limited thereto.
상기 건조하는 단계는 태양 자연건조, 오븐 건조, 진공 동결건조, 대기 순환 건조(기류건조), 질소 충진 방식 건조 및 이들의 조합들로 이루어진 건조 방법에 의해 건조될 수 있으나, 이에 제한되는 것은 아니다. The drying step may be dried by a drying method consisting of natural solar drying, oven drying, vacuum freeze drying, atmospheric circulation drying (airflow drying), nitrogen-filled drying, and combinations thereof, but is not limited thereto.
상기 실리콘 코어 입자를 기류에 의한 상호충돌로 파괴시켜 나노화하는 것 일 수 있으나, 이에 제한되는 것은 아니다. The silicon core particles may be destroyed by mutual collision by airflow to be nanosized, but the present invention is not limited thereto.
상기 나노화 공정에 있어서, 물리적 방법을 사용할 경우, 대량 생산이 가능하지만 오염이 발생할 가능성이 있고 일정 크기 이하로 제조하기 어려운 단점이 있다. 하지만, 기류를 이용한 나노화 공정은 저가 대량생산이 가능하며, 오염이 발생하지 않는 장점이 있다. In the nanoization process, when a physical method is used, mass production is possible, but there is a possibility that contamination may occur and it is difficult to manufacture to a certain size or less. However, the nanoization process using the airflow has the advantage that low-cost mass production is possible and contamination does not occur.
상기 실리콘 코어 입자는 SiCl 4, Si, SiOx, SiO 및 이들의 조합들로 이루어진 군에서 선택된 물질을 건조시키는 것 일 수 있으나, 이에 제한되는 것은 아니다. The silicon core particles may be obtained by drying a material selected from the group consisting of SiCl 4 , Si, SiOx, SiO, and combinations thereof, but is not limited thereto.
이어서, 상기 실리콘 코어 입자를 산화제 하에서 산화시켜 상기 실리콘 코어 입자 상에 실리콘 산화물을 포함하는 제 1 쉘을 형성한다(S200). Next, the silicon core particles are oxidized under an oxidizing agent to form a first shell including silicon oxide on the silicon core particles ( S200 ).
상기 산화제는 H 2O, 산소, 액체산소, 수소 및 이들의 조합들로 이루어진 군으로부터 선택된 산화제를 포함하는 것 일 수 있으나, 이에 제한되는 것은 아니다. The oxidizing agent may include an oxidizing agent selected from the group consisting of H 2 O, oxygen, liquid oxygen, hydrogen, and combinations thereof, but is not limited thereto.
상기 산화제는 순도 99.9% 이상 액체 산소인 것 일 수 있으나, 이에 제한되는 것은 아니다. The oxidizing agent may be liquid oxygen having a purity of 99.9% or more, but is not limited thereto.
상기 산화제를 주입할 때 공기와 함께 혼합하는 것 일 수 있으나, 이에 제한되는 것은 아니다. When the oxidizing agent is injected, it may be mixed with air, but is not limited thereto.
상기 산화제의 투입량은 상기 혼합물의 투입량에 따라 조절할 수 있다.The input amount of the oxidizing agent may be adjusted according to the input amount of the mixture.
이어서, 상기 제 1 쉘이 형성된 입자를 탄소 소스와 혼합 및 제 1 열처리하여 상기 제 1 쉘의 표면 상에 탄소를 포함하는 제 2 쉘을 형성한다(S300). Subsequently, the particles on which the first shell is formed are mixed with a carbon source and subjected to a first heat treatment to form a second shell including carbon on the surface of the first shell ( S300 ).
상기 제 1 쉘이 형성된 입자 및 상기 탄소 소스를 볼밀로 혼합함으로써 상기 실리콘 코어 입자가 응집되는 것을 방지하면서 미세화하여 분산시킬 수 있다. 이에, 나노 입자의 비표면이 감소되고 비가역 용량이 증가하는 것을 방지할 수 있다. By mixing the particles on which the first shell is formed and the carbon source with a ball mill, the silicon core particles may be finely dispersed while preventing agglomeration. Accordingly, it is possible to prevent the specific surface of the nanoparticles from being reduced and the irreversible capacity from increasing.
상기 탄소 소스는 그래핀, 그래파이트, 하드카본, 소프트카본, 천연 흑연, 인조흑연, 피치, 카본블랙, 탄소나노튜브 및 이들의 조합들로 이루어진 군에서 선택된 것 일 수 있으나, 이에 제한되는 것은 아니다. The carbon source may be selected from the group consisting of graphene, graphite, hard carbon, soft carbon, natural graphite, artificial graphite, pitch, carbon black, carbon nanotubes, and combinations thereof, but is not limited thereto.
상기 탄소 소스는 카본블랙 및 핏치를 복합화한 것 일 수 있으나, 이에 제한되는 것은 아니다. The carbon source may be a composite of carbon black and pitch, but is not limited thereto.
상기 제 1 열처리를 통해서 상기 제 1 쉘이 형성된 입자 상에 상기 제 2 쉘이 접촉되어 형성되며, 상기 제 2 쉘의 탄소로 인해 전도성을 향상시킬 수 있다.The second shell is formed by contacting the particles on which the first shell is formed through the first heat treatment, and conductivity may be improved due to the carbon of the second shell.
이어서, 상기 제 2 쉘이 형성된 입자를 고분자 바인더와 혼합하여 혼합물을 제조한다(S400). Next, the particles on which the second shell is formed are mixed with a polymer binder to prepare a mixture (S400).
상기 고분자 바인더는 두 개 이상의 고분자가 가교 결합으로 이루어져 있는 것 일 수 있으나, 이에 제한되는 것은 아니다. The polymer binder may be one in which two or more polymers are crosslinked, but is not limited thereto.
상기 가교 결합은 폴리아크릴산, 폴리비닐알콜, 폴리아크릴아케이트, 폴리비닐아프릴산, 폴리아마이드, 폴리비닐리텐, 폴리아미드이미드, 폴리에틸렌 및 폴리프로필렌 중에서 선택된 두 개 이상의 고분자, 시트르산, 글리세롤 및 액상 구리를 혼합하여 이루어지는 것 일 수 있으나, 이에 제한되는 것은 아니다. The crosslinking is polyacrylic acid, polyvinyl alcohol, polyacrylic acid, polyvinyl acrylic acid, polyamide, polyvinylithene, polyamideimide, at least two polymers selected from polyethylene and polypropylene, citric acid, glycerol and liquid copper. It may be made by mixing, but is not limited thereto.
상기 가교 결합은 30℃내지 80℃의 온도에서 1 시간 내지 3 시간동안 반응시켜 이루어지는 것 일 수 있으나, 이에 제한되는 것은 아니다. The crosslinking may be formed by reacting at a temperature of 30°C to 80°C for 1 hour to 3 hours, but is not limited thereto.
상기 가교 결합이 이루어짐으로써 상기 고분자 바인더가 겔화되며, 스마트 볼 역할을 수행할 수 있다. As the cross-linking is made, the polymer binder is gelled, and it can serve as a smart ball.
이어서, 상기 혼합물을 가압 및 열처리한다(S500). Then, the mixture is pressurized and heat-treated (S500).
상기 혼합물은 슬러리 형태로 수득되는 것 일 수 있으나, 이에 제한되는 것은 아니다. The mixture may be obtained in the form of a slurry, but is not limited thereto.
상기 슬러리의 크기는 1 mm 내지 10 cm인 것 일 수 있으나, 이에 제한되는 것은 아니다. The size of the slurry may be 1 mm to 10 cm, but is not limited thereto.
상기 슬러리는 가압, 성형, 건조, 분쇄, 분급 및 이들의 조합들로 이루어진 군에서 선택된 공정에 의해 처리되는 것 일 수 있으나, 이에 제한되는 것은 아니다. The slurry may be processed by a process selected from the group consisting of pressurization, molding, drying, grinding, classification, and combinations thereof, but is not limited thereto.
상기 가압은 1 ton/cm 2 내지 20 ton/cm 2의 압력을 가하는 것 일 수 있으나, 이에 제한되는 것은 아니다. The pressurization may be to apply a pressure of 1 ton/cm 2 to 20 ton/cm 2 , but is not limited thereto.
상기 제 2 열처리는 100℃내지 300℃의 온도에서 이루어지는 것 일 수 있으나, 이에 제한되는 것은 아니다. The second heat treatment may be performed at a temperature of 100°C to 300°C, but is not limited thereto.
상기 가압 및 제 2 열처리를 통해서 상기 혼합물이 일정한 형태로 성형되는 것 일 수 있다. 상기 성형의 형태는 제한되지 않으며, 예를 들면, 구형, 원통형, 육면체 등의 형태일 수 있다. Through the pressurization and the second heat treatment, the mixture may be molded into a predetermined shape. The shape of the molding is not limited, and may be, for example, a spherical shape, a cylindrical shape, or a hexahedral shape.
상기 성형은 스크류 압출방식 또는 금형 압착 방식에 의해 수행되는 것 일 수 있다. 상기 스크류 압출 방식으로 제조되는 구형 형태는 이동성이 유리하고 잔류 수분 건조 공정에 효과적일 수 있다. The molding may be performed by a screw extrusion method or a mold compression method. The spherical shape manufactured by the screw extrusion method may have advantageous mobility and may be effective in drying residual moisture.
상기 성형된 혼합물은 150℃ 내지 800℃의 온도 하에서 건조되는 단계를 더 포함하는 것 일 수 있으나, 이에 제한되는 것은 아니다. The molded mixture may further include a step of drying under a temperature of 150° C. to 800° C., but is not limited thereto.
이어서, 상기 가압 및 제 2 열처리된 혼합물을 분쇄한다(S600). Then, the pressurized and second heat-treated mixture is pulverized (S600).
상기 분쇄는 산업용 볼밀 또는 고속 기류에 의한 충돌에 의해서 분쇄됨에 따라 분급화되는 것 일 수 있으나, 이에 제한되는 것은 아니다. The pulverization may be classified as being pulverized by an industrial ball mill or collision by a high-speed air stream, but is not limited thereto.
상기 분쇄는 리튬이차전지용 음극활물질의 크기가 20 nm 내지 10 μm가 되도록 분쇄하는 것 일 수 있으나, 이에 제한되는 것은 아니다. 상기 리튬이차전지용 음극활물질의 크기는 더욱 바람직하게는 5 μm 내지 10 μm인 것 일 수 있으나, 이에 제한되는 것은 아니다. The pulverization may be pulverizing so that the anode active material for a lithium secondary battery has a size of 20 nm to 10 μm, but is not limited thereto. The size of the negative active material for a lithium secondary battery may be more preferably 5 μm to 10 μm, but is not limited thereto.
상기 리튬이차전지용 음극활물질을 포함하는 전극은 저렴하고 상용화 되어 있는 실리콘을 사용함으로써 공정의 저가화를 이룰 수 있다.The electrode including the negative electrode active material for the lithium secondary battery can achieve a cost reduction in the process by using inexpensive and commercially available silicon.
본원은 상기 리튬이차전지용 음극활물질을 포함하는, 리튬 이차전지를 제공한다. The present application provides a lithium secondary battery comprising the anode active material for a lithium secondary battery.
상기 리튬 이차전지는 상기 리튬이차전지용 음극활물질을 포함함으로써, 충방전 효율, 수명 특성 등이 향상되는 것 일 수 있다. The lithium secondary battery may include the anode active material for the lithium secondary battery, and thus charge/discharge efficiency and lifespan characteristics may be improved.
이하 실시예를 통하여 본 발명을 더욱 상세하게 설명하고자 하나, 하기의 실시예는 단지 설명의 목적을 위한 것이며 본원의 범위를 한정하고자 하는 것은 아니다.The present invention will be described in more detail through the following examples, but the following examples are for illustrative purposes only and are not intended to limit the scope of the present application.
[실시예 1][Example 1]
먼저, 실리콘 60 중량부, 카본블랙(30~40nm 입자) 58~59 중량부 및 시트르산 1~2 중량%를 밀링 혼합하여 나노입자를 제조하였다. First, nanoparticles were prepared by milling and mixing 60 parts by weight of silicon, 58 to 59 parts by weight of carbon black (30-40 nm particles), and 1-2% by weight of citric acid.
폴리비닐알콜 및 폴리아크릴산을 1:9 비율로 혼합한 것을 20 wt% (용매: 물) 농도의 용액으로 준비하였다. 상기 용액을 시트르산 및 글리세롤, 액상구리와 혼합한 후, 60℃의 온도에서 2시간동안 가교 결합시켜 고분자 바인더를 제조하였다. A mixture of polyvinyl alcohol and polyacrylic acid in a ratio of 1:9 was prepared as a solution having a concentration of 20 wt% (solvent: water). The solution was mixed with citric acid, glycerol, and liquid copper, and then cross-linked at a temperature of 60° C. for 2 hours to prepare a polymer binder.
상기 나노입자 100 중량부에 있어서 상기 고분자 바인더 10 중량부를 100~300℃로 2ton/cm 2의 압력으로 가압 사출 하여 케익 또는 구형볼 형태로 제조하였다. 상기 케익 또는 구형볼을 200℃의 온도에서 20분 건조시킨 후, 제트밀을 이용하여 5~15um점위로 분쇄하였다. 분쇄 후 635 mesh(20μm)의 체를 이용하여 분급하여 리튬이차전지용 음극활물질을 수득하였다. In 100 parts by weight of the nanoparticles, 10 parts by weight of the polymer binder was press-injected at 100 to 300° C. under a pressure of 2 ton/cm 2 to prepare a cake or spherical ball shape. The cake or spherical ball was dried at a temperature of 200° C. for 20 minutes, and then pulverized to a point of 5 to 15 μm using a jet mill. After pulverization, it was classified using a 635 mesh (20 μm) sieve to obtain an anode active material for a lithium secondary battery.
[제조예 1][Production Example 1]
상기 실시예 1에서 제조한 리튬이차전지용 음극활물질 슬러리와 PVDF전도성 바인더를 준비한 후 증류수에 투입한 후 균일하게 혼합하여 2차 슬러리를 만들었다. 상기 2차 슬러리를 구리(Cu) 집전체에 균일하게 도포한 후 롤 프레스에 압착한 뒤 건조하여 음극을 제조하였다. 구체적으로 로딩량 5 mg/cm 2를 전극 밀도가 1.2내지 1.3g/CC를 가지도록 하였다. 상대 전극으로는 리튬 금속(Li-metal)을 사용하고 전해액으로는 에틸렌 카보네이트(EC, ethylene carbonate) : 디메틸 카보네이트(DMC, dimethyl carbonate)의 부피 비율이 1:1인 혼합 용매에 1몰의 LiPF 6용액을 용해 시킨 것을 사용하였다.After preparing the negative electrode active material slurry for lithium secondary battery prepared in Example 1 and the PVDF conductive binder, they were added to distilled water, and then uniformly mixed to make a secondary slurry. The secondary slurry was uniformly coated on a copper (Cu) current collector, pressed on a roll press, and dried to prepare a negative electrode. Specifically, a loading amount of 5 mg/cm 2 was set to have an electrode density of 1.2 to 1.3 g/CC. Li-metal is used as the counter electrode and 1 mol of LiPF 6 in a mixed solvent in which the volume ratio of ethylene carbonate (EC): dimethyl carbonate (DMC) is 1:1 as the electrolyte. A dissolved solution was used.
상기 음극 리튬 금속 및 전해액을 이용하여 통상적인 제조 방법에 따라 CR2032 전지(half cell)를 제조하였다.A CR2032 battery (half cell) was prepared according to a conventional manufacturing method using the negative electrode lithium metal and the electrolyte.
[비교예 1][Comparative Example 1]
실리콘-탄소계 혼합물 제조시 실리콘:카본블랙(슈퍼P)을 50:50으로 혼합하는 것을 제외하고, 상기 실시예 1과 동일한 방법으로 리튬 이차전지용 음극활물질을 제조하였다. An anode active material for a lithium secondary battery was prepared in the same manner as in Example 1, except that silicon:carbon black (super P) was mixed in a ratio of 50:50 when preparing the silicon-carbon-based mixture.
[비교 제조예 1][Comparative Preparation Example 1]
상기 비교예 1에서 제조한 리튬이차전지용 음극활물질을 사용하는 것을 제외하고, 상기 제조예 1과 동일한 방법으로 리튬이차전지를 제조하였다. A lithium secondary battery was manufactured in the same manner as in Preparation Example 1, except that the anode active material for a lithium secondary battery prepared in Comparative Example 1 was used.
[평가][evaluation]
1.One. 리튬이차전지용 음극활물질의 특성 분석Characteristics analysis of negative electrode active material for lithium secondary battery
상기 실시예 1 에서 제조된 리튬이차전지용 음극활물질의 특성을 관찰하였고, 그 결과를 도 4 내지 도 9로서 나타내었다. The characteristics of the negative active material for a lithium secondary battery prepared in Example 1 were observed, and the results are shown in FIGS. 4 to 9 .
도 4는 본 실시예에 따라 제조된 나노 입자의 TEM (transmission electron microscope) 이미지이다.4 is a TEM (transmission electron microscope) image of nanoparticles prepared according to the present embodiment.
도 5는 본 실시예에 따라 제조된 나노 입자의 FIB (focused ion beam) 이미지이다.5 is a FIB (focused ion beam) image of the nanoparticles prepared according to the present embodiment.
도 6은 본 실시예에 따라 제조된 나노 입자의 TEM-mapping (transmission electron microscope mapping) 이미지이다.6 is a TEM-mapping (transmission electron microscope mapping) image of nanoparticles prepared according to the present embodiment.
도 6에 나타난 결과에 따르면, 본 실시예에 따라 제조된 나노 입자는 Si, O가 고르게 형성되어 있는 것을 확인할 수 있다. According to the results shown in FIG. 6 , it can be confirmed that Si and O are uniformly formed in the nanoparticles prepared according to the present embodiment.
도 7은 본 실시예에 따라 제조된 나노 입자의 SEM (scanning electron microscope) 이미지이다.7 is a scanning electron microscope (SEM) image of nanoparticles prepared according to the present embodiment.
도 8은 본 실시예에 따라 제조된 나노 입자의 TEM-mapping (transmission electron microscope mapping) 이미지이다.8 is a TEM-mapping (transmission electron microscope mapping) image of nanoparticles prepared according to the present embodiment.
도 8에 나타난 결과에 따르면, 본 실시예에 따라 제조된 나노 입자는 Si, O 및 C가 고르게 형성되어 있는 것을 확인할 수 있다. According to the results shown in FIG. 8 , it can be confirmed that Si, O, and C are uniformly formed in the nanoparticles prepared according to the present embodiment.
도 9은 본 실시예에 따라 제조된 리튬이차전지용 음극활물질의 TEM (transmission electron microscope) 이미지이다. 9 is a TEM (transmission electron microscope) image of the anode active material for a lithium secondary battery prepared according to the present embodiment.
도 10는 본 실시예에 따라 제조된 리튬이차전지용 음극활물질의 SEM(scanning electron microscope) 이미지이다.10 is a scanning electron microscope (SEM) image of an anode active material for a lithium secondary battery manufactured according to this embodiment.
2.2. 이차전지의 전기적 특성 분석Electrical Characteristics Analysis of Secondary Battery
상기 제조예 1 에서 제조된 리튬 이차전지의 특성을 관찰하였고 그 결과를 도 11 내지 도 13로서 나타내었다. The characteristics of the lithium secondary battery prepared in Preparation Example 1 were observed, and the results are shown in FIGS. 11 to 13 .
도 11은 본 제조예에 따른 이차전지 코인셀의 구성을 나타낸 도면이다. 11 is a view showing the configuration of the secondary battery coin cell according to the present manufacturing example.
도 12은 본 제조예에 따른 이차전지 코인셀의 사이클에 따른 용량 변화를 나타낸 그래프이다. 12 is a graph showing the change in capacity according to the cycle of the coin cell of the secondary battery according to the present preparation example.
도 13는 본 제조예에 따른 이차전지 코인셀의 초기 충방전 효율을 나타낸 그래프이다. 13 is a graph showing the initial charge/discharge efficiency of the coin cell of the secondary battery according to the present manufacturing example.
상기 제조예 1 및 비교 제조예 1에서 제조된 리튬 이차전지의 특성을 측정하였고, 그 결과를 하기 표 1로서 나타내었다. The characteristics of the lithium secondary batteries prepared in Preparation Example 1 and Comparative Preparation Example 1 were measured, and the results are shown in Table 1 below.
Tab밀도 (g/cc)Tab density (g/cc) 비표면적
(cm 2/g)specific surface area
(cm 2 /g) 		초기충전용량
(mAh/g)initial charging capacity
(mAh/g) 		초기방전용량
(mAh/g)Initial discharge capacity
(mAh/g) 		초기효율 (%)Initial efficiency (%) Cycle 유지 용량
(mAh/g)Cycle holding capacity
(mAh/g)
실시예1Example 1 0.320.32 23.2923.29 1,640.81,640.8 1,3571,357 82.782.7 1,329.91,329.9
비교예1Comparative Example 1 0.450.45 26.1126.11 1,838.31,838.3 1,492.71,492.7 81.281.2 1,462.81,462.8
탭밀도는 ASTM-B527에 근거 50ml 용기에 10g의 분말을 넣은 후 3000cycle @284cycle/min으로 탭핑(tapping)시켜 충전 밀도를 측정하였다. The tap density was measured by tapping at 3000 cycles @ 284 cycles/min after putting 10 g of powder in a 50 ml container based on ASTM-B527 to measure the packing density.
비표면적은 BET법 (surface area and porosity analyzer), (micromeritices, ASAP2020)을 이용하여 측정하였다.The specific surface area was measured using the BET method (surface area and porosity analyzer), (micromeritices, ASAP2020).
초기 충방전 용량 및 효율은 상기 실시예에서 제조된 리튬이차전지용 음극활물질을 반쪽 전지에 적용하여 시험하였다. 구체적으로 0.1C, 5mV, 0.005C cut-off 충전 및 0.1C, 1.5V cut-off 방전의 조건으로 전지를 구동하고 초기 방전 용량 및 초기 효율을 측정하였다. The initial charge/discharge capacity and efficiency were tested by applying the negative active material for a lithium secondary battery prepared in Example above to the half battery. Specifically, the battery was driven under the conditions of 0.1C, 5mV, 0.005C cut-off charging and 0.1C, 1.5V cut-off discharge, and initial discharge capacity and initial efficiency were measured.
팽창율은 상기 실시예에서 제조된 리튬이차전지용 음극활물질을 반쪽 전지에 적용하여 시험하였다. 구체적으로, 0.1C, 5mV, 0.005C cut-off 충전 및 0.1C, 1.5V cut-off 방전의 조건으로 전지를 1st, 20th, 50th cycle 구동하고 전지를 해체하여 측정한 전극의 두께 변화율을 계산하여 측정하였다. The expansion rate was tested by applying the negative active material for a lithium secondary battery prepared in Example above to the half battery. Specifically, the battery is operated for 1st, 20th, and 50th cycles under the conditions of 0.1C, 5mV, 0.005C cut-off charge and 0.1C, 1.5V cut-off discharge, and the thickness change rate of the electrode measured by disassembling the battery is calculated. measured.
수명은 상기 제조예에서 제조된 리튬 이차전지(full-cell)을 이용하여 측정하였다. 구체적으로 상용 C.B(carbon black)과 합성된 Si-탄소 복합 음극제를 혼합 음극 용량을 10mAh/g으로 유지하고 상용LCO를 양극으로 한 CR 2032 coin full cell을 제조한 후 0.5C(충전)/1.0C(방전)을 통해 장기 수명을 측정하였다.Lifespan was measured using the lithium secondary battery (full-cell) prepared in Preparation Example. Specifically, after manufacturing a CR 2032 coin full cell using commercial C.B (carbon black) and synthesized Si-carbon composite negative electrode with a mixed negative electrode capacity of 10 mAh/g and commercial LCO as the positive electrode, 0.5C (charge)/1.0 Long-term lifetime was measured through C (discharge).
상기 표 1에 나타난 결과에 따르면, 실시예 1내지 2의 경우 비교예1에 비해 비표면적 값이 현저하게 작은 결과를 알 수 있다. 이는 PAA-PVA 고분자 바인더에 의해 실리콘 비표면적이 고압 가열 사출 성형시 높은 결착력을 나타낸 것이다. 일부 탄소(C.B)가 바인더와 일정 점성을 가지면서 나노 실리콘 입자 표면 커버리지(coverage) 특성이 향상되었음을 의미한다.According to the results shown in Table 1, in the case of Examples 1 and 2, it can be seen that the specific surface area value was significantly smaller than that of Comparative Example 1. This indicates that the silicone specific surface area exhibited high bonding strength during high-pressure heating injection molding by the PAA-PVA polymer binder. While some carbon (C.B) has a certain viscosity with the binder, it means that the surface coverage characteristics of the nano-silicon particles are improved.
전술한 본원의 설명은 예시를 위한 것이며, 본원이 속하는 기술분야의 통상의 지식을 가진 자는 본원의 기술적 사상이나 필수적인 특징을 변경하지 않고서 다른 구체적인 형태로 쉽게 변형이 가능하다는 것을 이해할 수 있을 것이다. 그러므로 이상에서 기술한 실시예들은 모든 면에서 예시 적인 것이며 한정적이 아닌 것으로 이해해야만 한다. 예를 들어, 단일형으로 설명되어 있는 각 구성 요소는 분산되어 실시될 수도 있으며, 마찬가지로 분산된 것으로 설명되어 있는 구성 요소들도 결합된 형태로 실시될 수 있다.The above description of the present application is for illustration, and those of ordinary skill in the art to which the present application pertains will understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present application. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a dispersed form, and likewise components described as distributed may also be implemented in a combined form.
본원의 범위는 상기 상세한 설명보다는 후술하는 특허청구범위에 의하여 나타내어지며, 특허청구범위의 의미 및 범위 그리고 그 균등 개념으로부터 도출되는 모든 변경 또는 변형된 형태가 본원의 범위에 포함되는 것으로 해석되어야 한다.The scope of the present application is indicated by the following claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present application.
[부호의 설명][Explanation of code]
100: 리튬이차전지용 음극활물질100: negative electrode active material for lithium secondary battery
110: 나노입자110: nanoparticles
111: 코어111: core
112: 제 1 쉘112: first shell
113: 제 2 쉘113: second shell
120: 고분자 바인더 120: polymer binder

Claims (20)

  1. 나노 입자; 및nanoparticles; and
    상기 나노 입자를 적어도 하나 이상 둘러싸고 있는 고분자 바인더;를 포함하며, Including; a polymer binder surrounding at least one or more of the nanoparticles,
    상기 나노 입자는 실리콘을 포함하는 코어; The nanoparticles may include a core including silicon;
    상기 코어의 표면 상에 형성되어 있고, 실리콘 산화물을 포함하는 제 1 쉘; 및a first shell formed on the surface of the core and including silicon oxide; and
    상기 제 1 쉘의 표면 상에 형성되어 있고, 탄소를 포함하는 제 2 쉘;을 포함하는 것인, 리튬이차전지용 음극활물질. Formed on the surface of the first shell, the second shell comprising carbon; which will include, a negative electrode active material for a lithium secondary battery.
  2. 제 1 항에 있어서, The method of claim 1,
    상기 실리콘 코어는 리튬이 도핑되어 있는 것인, 리튬이차전지용 음극활물질. The silicon core is doped with lithium, a negative active material for a lithium secondary battery.
  3. 제 1 항에 있어서, The method of claim 1,
    상기 나노 입자의 직경은 10 nm 내지 500 μm인, 리튬이차전지용 음극활물질.The diameter of the nanoparticles is 10 nm to 500 μm, a negative electrode active material for a lithium secondary battery.
  4. 제 1 항에 있어서, The method of claim 1,
    상기 제 1 쉘의 두께는 0.1 nm 내지 100 nm인, 리튬이차전지용 음극활물질.The thickness of the first shell is 0.1 nm to 100 nm, a negative electrode active material for a lithium secondary battery.
  5. 제 1 항에 있어서, The method of claim 1,
    상기 제 2 쉘의 두께는 10 nm 내지 50 nm인, 리튬이차전지용 음극활물질.The thickness of the second shell is 10 nm to 50 nm, a negative electrode active material for a lithium secondary battery.
  6. 제 1 항에 있어서, The method of claim 1,
    상기 고분자 바인더는 두 개 이상의 고분자가 가교 결합으로 이루어져 있으며, 전도성 및 수복 탄성을 가지는 것인, 리튬이차전지용 음극활물질.The polymer binder is composed of two or more polymers cross-linked, and has conductivity and restorative elasticity, a negative electrode active material for a lithium secondary battery.
  7. 제 6 항에 있어서, 7. The method of claim 6,
    상기 고분자 바인더는 폴리아크릴산, 폴리비닐알콜, 폴리아크릴아케이트, 폴리비닐아크릴산, 폴리아마이드, 폴리비닐리텐, 폴리아미드이미드, 폴리에틸렌, 폴리프로필렌 및 이들의 조합들로 이루어진 군에서 선택된 고분자를 포함하는 것인, 리튬이차전지용 음극활물질.The polymer binder includes a polymer selected from the group consisting of polyacrylic acid, polyvinyl alcohol, polyacryl acrylate, polyvinyl acrylic acid, polyamide, polyvinylithene, polyamideimide, polyethylene, polypropylene, and combinations thereof. , anode active material for lithium secondary batteries.
  8. 제 6 항에 있어서, 7. The method of claim 6,
    상기 고분자 바인더는 폴리아크릴산 및 폴리비닐알콜이 가교결합으로 이루어져 있는 것인, 리튬이차전지용 음극활물질.The polymer binder is a negative electrode active material for a lithium secondary battery, which is composed of polyacrylic acid and polyvinyl alcohol cross-linked.
  9. 제 1 항에 있어서, The method of claim 1,
    상기 실리콘 산화물은 SiO x이며, 상기 x는 0.1 내지 1.6인 것인, 리튬이차전지용 음극활물질. The silicon oxide is SiO x , wherein x is 0.1 to 1.6, the negative electrode active material for a lithium secondary battery.
  10. 제 1 항에 있어서, The method of claim 1,
    상기 실리콘은 정질 또는 비정질인 것인, 리튬이차전지용 음극활물질.The silicon is crystalline or amorphous, a negative electrode active material for a lithium secondary battery.
  11. 실리콘 코어 입자를 건조하는 단계; drying the silicon core particles;
    상기 실리콘 코어 입자를 산화제 하에서 산화시켜 상기 실리콘 코어 입자 상에 실리콘 산화물을 포함하는 제 1 쉘을 형성하는 단계; oxidizing the silicon core particles under an oxidizing agent to form a first shell including silicon oxide on the silicon core particles;
    상기 제 1 쉘이 형성된 입자를 탄소 소스와 혼합 및 분쇄하여 상기 제 1 쉘의 표면 상에 탄소를 포함하는 제 2 쉘을 형성하는 단계; mixing and pulverizing the particles on which the first shell is formed with a carbon source to form a second shell including carbon on the surface of the first shell;
    상기 제 2 쉘이 형성된 입자를 고분자 바인더와 혼합하여 혼합물을 제조하는 단계; preparing a mixture by mixing the particles on which the second shell is formed with a polymer binder;
    상기 혼합물을 가압 및 열처리하는 단계; 및pressurizing and heat-treating the mixture; and
    상기 가압 및 열처리된 혼합물을 분쇄하는 단계;를 포함하는, 리튬이차전지용 음극활물질의 제조 방법. A method of manufacturing a negative electrode active material for a lithium secondary battery, including; pulverizing the pressurized and heat-treated mixture.
  12. 제 11 항에 있어서, 12. The method of claim 11,
    건조하는 단계 이전에, 상기 실리콘 코어 입자를 리튬 화합물과 혼합하는 단계;를 더 포함하는 것인, 리튬이차전지용 음극활물질의 제조 방법.Prior to the drying step, mixing the silicon core particles with a lithium compound; further comprising a method of manufacturing a negative electrode active material for a lithium secondary battery.
  13. 제 11 항에 있어서, 12. The method of claim 11,
    상기 건조하는 단계는 상기 실리콘 코어 입자의 수분이 1% 내지 20%로 건조하는 것인, 리튬이차전지용 음극활물질의 제조 방법. The drying step is to dry the moisture of the silicon core particles to 1% to 20%, a method of manufacturing a negative electrode active material for a lithium secondary battery.
  14. 제 11 항에 있어서, 12. The method of claim 11,
    상기 고분자 바인더는 두 개 이상의 고분자가 가교 결합으로 이루어져 있는 것인, 리튬이차전지용 음극활물질의 제조 방법.The polymer binder is a method for producing a negative electrode active material for a lithium secondary battery, which is composed of two or more polymers cross-linked.
  15. 제 14 항에 있어서, 15. The method of claim 14,
    상기 가교 결합은 폴리아크릴산, 폴리비닐알콜, 폴리아크릴아케이트, 폴리비닐아크릴산, 폴리아마이드, 폴리비닐리텐, 폴리아미드이미드, 폴리에틸렌 및 리프로필렌 중에서 선택된 두 개 이상의 고분자, 시트르산, 글리세롤 및 액상 구리를 혼합하여 이루어지는 것인, 리튬이차전지용 음극활물질의 제조 방법.The crosslinking is carried out by mixing two or more polymers selected from polyacrylic acid, polyvinyl alcohol, polyacrylicate, polyvinylacrylic acid, polyamide, polyvinylithene, polyamideimide, polyethylene, and repropylene, citric acid, glycerol and liquid copper. A method of manufacturing a negative electrode active material for a lithium secondary battery that is made.
  16. 제 14 항에 있어서, 15. The method of claim 14,
    상기 가교 결합은 30℃ 내지 80℃의 온도에서 1 시간 내지 3 시간동안 반응시켜 이루어지는 것인, 리튬이차전지용 음극활물질의 제조 방법.The cross-linking is made by reacting at a temperature of 30°C to 80°C for 1 hour to 3 hours, a method for producing a negative active material for a lithium secondary battery.
  17. 제 11 항에 있어서, 12. The method of claim 11,
    상기 가압은 1 ton/cm 2 내지 20 ton/cm 2의 압력을 가하는 것인, 리튬이차전지용 음극활물질의 제조 방법.The pressurization is to apply a pressure of 1 ton/cm 2 to 20 ton/cm 2 A method of manufacturing a negative electrode active material for a lithium secondary battery.
  18. 제 11 항에 있어서, 12. The method of claim 11,
    상기 열처리는 150℃ 내지 800℃의 온도에서 이루어지는 것인, 리튬이차전지용 음극활물질의 제조 방법.The heat treatment is made at a temperature of 150 ℃ to 800 ℃, a method of manufacturing a negative electrode active material for a lithium secondary battery.
  19. 제 11 항에 있어서, 12. The method of claim 11,
    상기 탄소 소스는 그래핀, 그래파이트, 하드카본, 소프트카본, 천연 흑연, 인조흑연, 피치, 카본블랙, CNT 및 이들의 조합들로 이루어진 군에서 선택된 것인, 리튬이차전지용 음극활물질의 제조 방법.The carbon source is selected from the group consisting of graphene, graphite, hard carbon, soft carbon, natural graphite, artificial graphite, pitch, carbon black, CNT, and combinations thereof, a method of manufacturing a negative electrode active material for a lithium secondary battery.
  20. 제 1 항 내지 제 10 항 중 어느 한 항에 따른 리튬이차전지용 음극활물질을 포함하는, 리튬 이차전지.A lithium secondary battery comprising the anode active material for a lithium secondary battery according to any one of claims 1 to 10.
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KR20170033123A (en) * 2015-09-16 2017-03-24 삼성전자주식회사 Electrode active material, electrode and secondary battery including the same, and method of preparing the electrode active material
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US20190051904A1 (en) * 2017-08-14 2019-02-14 Nanotek Instruments, Inc. Protected Particles of Anode Active Materials, Lithium Secondary Batteries Containing Same and Method of Manufacturing
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