WO2017164701A1 - Composition pour la formation d'une cathode d'accumulateur, et cathode d'accumulateur et accumulateur fabriqués à l'aide de ladite composition - Google Patents

Composition pour la formation d'une cathode d'accumulateur, et cathode d'accumulateur et accumulateur fabriqués à l'aide de ladite composition Download PDF

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WO2017164701A1
WO2017164701A1 PCT/KR2017/003219 KR2017003219W WO2017164701A1 WO 2017164701 A1 WO2017164701 A1 WO 2017164701A1 KR 2017003219 W KR2017003219 W KR 2017003219W WO 2017164701 A1 WO2017164701 A1 WO 2017164701A1
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Prior art keywords
conductive material
composition
positive electrode
forming
secondary battery
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English (en)
Korean (ko)
Inventor
안병훈
최상훈
유흥식
성기원
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LG Chem Ltd
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LG Chem Ltd
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Priority claimed from KR1020170036956A external-priority patent/KR102143953B1/ko
Application filed by LG Chem Ltd filed Critical LG Chem Ltd
Priority to US15/751,067 priority Critical patent/US10741829B2/en
Priority to EP17770671.0A priority patent/EP3331072B1/fr
Priority to CN201780002924.7A priority patent/CN107949940B/zh
Priority to JP2018515444A priority patent/JP6636141B2/ja
Priority to PL17770671T priority patent/PL3331072T3/pl
Publication of WO2017164701A1 publication Critical patent/WO2017164701A1/fr
Anticipated expiration legal-status Critical
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • 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
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • 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
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a composition for forming a cathode of a secondary battery capable of improving battery performance by increasing dispersibility of a conductive material, and a cathode and a secondary battery for a secondary battery manufactured using the same.
  • Fine carbon materials such as carbon black, ketjen black, fullerene, graphene or carbon nanotubes are widely used in the fields of energy, aerospace and the like due to their excellent electrical properties and thermal conductivity.
  • the uniform dispersion should be preceded, but it has not been easy to prepare a high concentration of fine carbon material dispersion by methods such as conventional mechanical dispersion, dispersion using a dispersant, and surface functionalization.
  • lithium secondary batteries having high energy density and voltage, long cycle life, and low self discharge rate have been commercialized and widely used.
  • the electrodes of the positive electrode and the negative electrode are manufactured by applying an electrode forming composition prepared by mixing an electrode active material and a binder with a solvent to a current collector and then drying them.
  • the conductive material of the fine carbon material is included in the composition for forming an electrode, and among these, the active material filling rate can be increased, and even a small amount can suppress an increase in battery internal resistance.
  • Carbon black is widely used in that it can be.
  • the conductive material is used as fine particles of several tens of nm level, the cohesive force is strong, and aggregation between the conductive material fine particles is likely to occur when dispersed in a solvent.
  • Such non-uniform dispersion of the conductive material in the electrode active material layer leads to a decrease in conductivity and a decrease in output characteristics of the battery.
  • the aggregate of the simply aggregated conductive material has a low structure holding force, the conductivity between the active materials can be degraded.
  • the binder since the conductive material has a large specific surface area, the binder may be adsorbed, resulting in non-uniform distribution of the binder in the active material layer and consequent decrease in adhesive strength.
  • a conductive material was previously dispersed together with a binder and a solvent to make a paste, and an electrode active material was added thereto, and stirred and mixed to solve the problem related to dispersion of the conductive material.
  • resin binders such as a fluororesin and a cellulose resin
  • dispersion stability of electroconductive material particle was bad and sufficient effect was not acquired, for example, a conductive material particle reaggregated.
  • the addition of the vinyl pyrrolidone type polymer as a dispersing agent to an electrically conductive material and a solvent has made the attempt to improve the dispersibility of an electrically conductive material, and to maintain favorable battery load characteristics and cycling characteristics through this.
  • the added vinyl pyrrolidone-based polymer has a problem of impairing battery characteristics, such as insulation coating of the electrode active material or deterioration and deterioration of discharge characteristics when stored for a long time in a charged state.
  • the first problem to be solved by the present invention is to provide a composition for forming a positive electrode of a secondary battery that can improve the battery performance by increasing the dispersibility of the conductive material and a method of manufacturing the same.
  • the second problem to be solved by the present invention is to provide a positive electrode and a secondary battery for a secondary battery is prepared using the composition for forming the positive electrode, the conductive material is uniformly dispersed.
  • the conductive material has a specific surface area of 130 m 2 / g or more, oil absorption amount 220 ml / 100 g or more carbon 0.1 wt% to 2 wt% of the base material based on the total weight of the composition for forming an anode, wherein the dispersant is introduced into the conductive material to form a conductive material-dispersant composite, and the conductive material-dispersant composite has a particle size distribution. It provides a composition for forming a positive electrode of a secondary battery having a D 50 of 0.8 ⁇ m to 1.2 ⁇ m.
  • a conductive material dispersion by milling a mixture of the conductive material and the dispersant in a solvent; And adding a positive electrode active material to the conductive material dispersion and mixing the conductive material, wherein the conductive material has a specific surface area of 130 m 2 / g or more and an oil absorption amount of 220 ml / 100g or more.
  • 0.1 wt% to 2 wt% of the conductive material dispersion wherein the conductive material dispersion includes a conductive material-dispersant composite in which the dispersant is introduced into the conductive material, and the conductive material-dispersant composite has a D 50 of a particle size distribution of 0.8 ⁇ m. It provides a method for producing a composition for forming a cathode of a secondary battery that is to 1.2 ⁇ m.
  • a cathode for a secondary battery manufactured using the composition for forming a cathode of the secondary battery, and a lithium secondary battery including the same.
  • the composition for forming a cathode of a secondary battery according to the present invention can greatly improve the performance, such as resistance characteristics, life characteristics, capacity characteristics and rate characteristics of the battery by uniformly dispersing the dispersibility conductive material in the composition.
  • the conductive material in the electrode When the dispersion of the conductive material in the electrode is insufficient, the conductive material may not be properly distributed on the surface of the active material, thereby degrading the performance of the battery cell and increasing the performance variation between the cells. In addition, when the conductive material is excessively dispersed, the dispersed conductive material may be advantageously distributed on the surface of the active material, but the network formation between the conductive materials is not easy, and thus the resistance in the cell is increased.
  • the conductive material is contained in the form of a conductive material-dispersant composite in which the dispersant is introduced through a physical or chemical bond to the surface of the conductive material when mixed with the dispersant.
  • the particle size distribution of the conductive material-dispersant composite formed at this time indicates the dispersibility of the conductive material in the composition.
  • the physical properties of the conductive material and the dispersant are controlled by combining the conductive materials and the dispersant in order to exhibit the optimum degree of dispersion in the electrode.
  • the dispersion of the hardly dispersible conductive material can be uniformly dispersed in the composition, and as a result, the performances such as resistance characteristics, life characteristics, capacity characteristics and rate characteristics of the battery can be greatly improved.
  • the composition for forming a cathode of a secondary battery includes a cathode active material, a conductive material and a dispersant, the conductive material has a specific surface area of 130 m 2 / g or more, oil absorption amount 220 ml / A carbon-based material of 100g or more is contained in an amount of 0.1% to 2% by weight based on the total weight of the composition for forming an anode, wherein the dispersant is introduced into the conductive material to form a conductive material-dispersant composite, and the conductive material-dispersant composite is D 50 of the particle size distribution is 0.8 ⁇ m to 1.2 ⁇ m.
  • the content of the carbonaceous material is a value based on the total weight of solids in the composition for forming an anode, unless otherwise specified.
  • the dispersibility of the conductive material is greatly improved. As a result, it is possible to improve battery performance by reducing the resistance characteristics within the electrode during electrode formation. If the D 50 of the particle size distribution of the conductive material-dispersant composite is less than 0.8 ⁇ m, the conductive material may be over-dispersed, so that the conductive material network may not be easily formed between the active materials in the electrode during the formation of the anode, and as a result, the cell resistance may increase. .
  • the conductive material-dispersant composite included in the anode-forming composition has a particle size distribution of D 50 of 0.8 ⁇ m to 1.2 ⁇ m and D 90 of 2.0 ⁇ m to It may be 5.0 ⁇ m or less.
  • the particle size distribution condition of the conductive material-dispersant composite is influenced by the physical properties and content of the conductive material and the dispersant, and in particular, the physical properties and content of the conductive material are greatly affected.
  • the amount of the conductive material included in the positive electrode forming composition is large, the dispersion may not be easy, so the difference according to the dispersion particle size may be insignificant.
  • the amount of the conductive material is less than a predetermined level, the optimum dispersion particle size according to the physical properties of the conductive material May exist.
  • the conductive material has a specific surface area (SSA) of 130 m 2 / g or more, and an oil absorption amount (OAN) of 220 ml / 100g or more of carbon
  • SSA specific surface area
  • OAN oil absorption amount
  • the base material is included in an amount of 0.1% by weight to 2% by weight based on the total weight of the composition for forming an anode.
  • SSA specific surface are
  • OAN Oil Absorption number
  • SSA specific surface are
  • OAN oil Absorption number
  • the specific surface area and the oil absorption number may be used as a numerical value indicating the structural characteristics of the carbonaceous material or the degree of structural development.
  • the carbon-based material having a secondary particle structure usually formed by granulation of primary particles, it means that the smaller the size of the primary particles, the larger the specific surface area and the oil absorption of the secondary particles, the more developed the structure. In this case, while exhibiting excellent conductivity, dispersibility may be lowered. Accordingly, considering the conductivity and dispersibility in the electrode, the developmental structure in the carbon-based material should be optimized.
  • the conductive material includes a carbonaceous material of secondary particles made by assembling primary particles, and the carbonaceous material has a specific surface area.
  • the 130 m 2 / g or more, the oil absorption may be 220 ml / 100g or more.
  • the carbonaceous material has an average particle diameter (D 50 ) of the primary particles of 15 nm to 35 nm, and the specific surface area of the secondary particles formed by assembling the primary particles is 130 m 2 / g to 270 m 2 / g, having a highly developed structure with an oil absorption amount of 220 ml / 100g to 400 ml / 100g, thereby exhibiting better conductivity and dispersibility, and in particular, three phases of the positive electrode active material and the electrolyte when applied in the positive electrode Reactivity can be improved by improving the electron supply property in an interface.
  • D 50 average particle diameter of the primary particles of 15 nm to 35 nm
  • the specific surface area of the secondary particles formed by assembling the primary particles is 130 m 2 / g to 270 m 2 / g, having a highly developed structure with an oil absorption amount of 220 ml / 100g to 400 ml / 100g, thereby exhibiting better conductivity and dispersibility, and in particular
  • the average particle diameter of the primary particles of the carbonaceous material is less than 15 nm, or if the specific surface area and oil absorption of the secondary particles exceed 270 m 2 / g and 400 ml / 100g, respectively, aggregation of the carbonaceous material may occur. In this case, dispersibility may decrease. In addition, if the average particle diameter exceeds 35 nm or the specific surface area and oil absorption of the secondary particles are less than 130 m 2 / g and less than 220 ml / 100g, respectively, the primary particles are too large in size and dispersed due to the lack of structural development of the conductive material.
  • the volume of the conductive material per weight is not small enough to cover the surface of the active material, and as a result there is a concern that the cell performance degradation and inter-cell performance deviations increase.
  • the average particle diameter of the primary particles of the carbonaceous material considering the remarkable effects of the specific surface area and oil absorption of the secondary particles on the conductivity and dispersibility, D 50), and a 20nm to 35nm, and the specific surface area of the secondary particles 130 m 2 / g to 270 m 2 / g, oil absorption may be one of 220 ml / 100g to 400 ml / 100g.
  • the average particle diameter (D 50 ) of the primary particles in the carbonaceous material may be defined as the particle size based on 50% of the particle size distribution.
  • the average particle diameter (D 50 ) of the carbonaceous material can be measured using, for example, a laser diffraction method. More specifically, the carbonaceous material is dispersed in a solvent and then sold. Introduced into a laser diffraction particle size measuring device (e.g., Microtrac MT 3000) and irradiating an ultrasonic wave of about 28 kHz with an output of 60 W, and then calculating the average particle diameter (D 50 ) based on 50% of the particle size distribution in the measuring device. Can be.
  • a laser diffraction particle size measuring device e.g., Microtrac MT 3000
  • the carbon-based material may be graphite such as natural graphite or artificial graphite; Carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black or thermal black; Or carbonaceous materials such as carbon fibers. More specifically, the carbonaceous material may be carbon black.
  • carbon black may be classified in various ways depending on the production method and the raw materials used.
  • Carbon black usable in the present invention may be acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, or denka black and the like, any one or a mixture of two or more may be used.
  • the carbon black is prepared using acetylene gas, specifically, is prepared by thermal decomposition of the acetylene gas under an oxygen-free atmosphere,
  • the average particle diameter (D 50 ) may be 20 nm to 30 nm.
  • the carbon black may control the content of metal impurities in the carbon black through an impurity control during the manufacturing process or a purification process after manufacture, specifically, the purity may be 99.5% or more.
  • a lithium secondary battery degrades its life characteristics as components deteriorate due to various causes.
  • One of the main causes is due to incorporation of metal impurities in a battery into a battery.
  • metal impurities such as iron (Fe) contained in the conductive material are dissolved in the electrolyte by reacting at an operating voltage range of about 3.0V to 4.5V of the lithium secondary battery, and the dissolved metal impurities are in the form of metal at the negative electrode. Is reprecipitated. The precipitated metal penetrates the separator and shorts with the positive electrode, causing a low voltage failure, and deteriorating the capacity characteristics and life characteristics of the secondary battery, thereby preventing its function as a battery.
  • the carbon black usable in the present invention may be carbon black having high purity in the above range in which the content of metal impurities is removed to the maximum.
  • the content of impurities in the carbon black may be determined by using magnetic, X-ray diffraction (XRD), differential thermal analysis (DTA), differential scanning Differential Scanning Calorimetry (DSC), Modulated Differential Scanning Calorimetry (MDSC), Thermogravimetric Analysis (TGA), Thermogravimetric-infrared (TG-IR) Analysis and Melting Point It can be analyzed or confirmed by a method that includes one or more thermal assays, including measurements. Specifically, the content of metal impurities in carbon black can be measured through the main peak intensity of the metal impurities obtained by X-ray diffraction (XRD).
  • XRD X-ray diffraction
  • the carbon black may be surface treated to increase the dispersibility in the dispersion.
  • the carbon black imparts hydrophilicity by introducing an oxygen-containing functional group on the surface of the carbon black by oxidation treatment;
  • hydrophobicity may be imparted by fluorination treatment or siliconization treatment on carbon black.
  • the carbon black may be coated with a phenol resin or subjected to a mechanical chemical treatment.
  • the carbon black when it is oxidized, it may be performed by heat treating the carbon black at about 500 ° C. to 700 ° C. for about 1 to 2 hours in air or under an oxygen atmosphere.
  • the surface treatment for the carbon black is excessive, since the electrical conductivity and strength characteristics of the carbon black itself may be greatly deteriorated, it may be desirable to control properly.
  • the carbon black may be iodine number (iodine number) measured according to ASTM D-1510 (200 mg / g to 400 mg / g), if the iodine number of the carbon black is 200 mg / If it is less than g it may be difficult to sufficiently disperse the carbon black, if it exceeds 400 mg / g may cause a problem that the conductivity is lowered.
  • iodine number measured according to ASTM D-1510 (200 mg / g to 400 mg / g)
  • the term "iodine number" is absorbed in 100 g of a sample by converting the amount of halogen absorbed into iodine when halogen is applied to a fat or fatty acid using a reaction in which a halogen is added to a double bond.
  • the amount of iodine is expressed in g, which is used as a numerical value indicating the number of double bonds of unsaturated fatty acids in a sample. The higher the iodine number, the higher the number of double bonds.
  • the carbonaceous material may be included in an amount of 0.1 wt% to 2 wt% based on the total weight of solids in the composition for forming an anode. If the content of the carbon-based material is less than 0.1% by weight, the conductivity improvement effect by using the carbon-based material is insignificant, and when the content of the carbon-based material is more than 2% by weight, the dispersibility is lowered and there is a fear of lowering the cell capacity. In consideration of the remarkable improvement effect of using the carbonaceous material, the carbonaceous material may be included in an amount of 0.5% by weight to 1.5% by weight based on the total weight of solids in the composition for forming an anode.
  • the conductive material may further include a conventional conductive material together with the carbon-based material to improve conductivity.
  • the conductive material may further include a fibrous conductive material that is easier to form a conductive network when used in combination with the carbon-based material, and easily forms a three-phase interface with the active material when the battery is applied.
  • the fibrous conductive material may be a fibrous conductive material having an aspect ratio (a ratio of the length of the long axis passing through the center of the fibrous conductive material and the diameter perpendicular to the long axis) such as carbon nanorods or carbon nanofibers.
  • the length of the fibrous conductive material affects the electrical conductivity, strength, and dispersibility of the dispersion. Specifically, the longer the length of the fibrous conductive material, the higher the electrical conductivity and the strength characteristics may be, but if the length is too long, there is a fear that the dispersibility is lowered. Accordingly, the aspect ratio of the fibrous conductive material usable in the present invention may be 5 to 50,000, more specifically 10 to 15,000.
  • the fibrous conductive material as described above may be used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the carbonaceous material. If the content of the fibrous conductive material is too low compared to the content of the carbonaceous material, the effect of improving conductivity due to the mixed use is insignificant, and if it exceeds 10 parts by weight, the dispersibility of the fibrous conductive material may be reduced.
  • the conductive material is dispersed in the dispersion medium in the form of a composite physically or chemically bonded to the dispersant.
  • the content of the repeating unit region of the structure capable of interacting with the conductive material and the repeating unit region of the structure capable of interacting with the dispersion medium when the composition for forming the anode using the conductive material is controlled is controlled.
  • the conductive material is uniformly dispersed in the dispersion medium, and further, low viscosity can be exhibited even at the time of dispersing a high concentration of the conductive material.
  • the dispersing agent is a repeating unit having an ⁇ , ⁇ -unsaturated nitrile-derived structure as a repeating unit region (A) of a structure capable of interacting with a carbon-based material;
  • the repeating unit region (B) of the structure capable of interacting with the dispersion medium may include a partially hydrogenated nitrile rubber comprising a repeating unit of a conjugated diene derived structure and a repeating unit of a hydrogenated conjugated diene derived structure.
  • the partially hydrogenated nitrile rubber may optionally further comprise additional comonomers copolymerizable under conditions such that the conductive material-dispersant composite has the above particle size distribution.
  • the polymerization reaction process and the hydrogenation process may be performed according to a conventional method.
  • ⁇ , ⁇ -unsaturated nitrile that can be used in the preparation of the partially hydrogenated nitrile rubber include acrylonitrile or methacrylonitrile, and one or more of these may be used.
  • conjugated diene which can be used at the time of manufacture of the said partially hydrogenated nitrile rubber can specifically mention conjugated diene of 4 to 6 carbon atoms, such as 1, 3- butadiene, isoprene, and 2, 3- methyl butadiene, Any one of these Or mixtures of two or more may be used.
  • copolymerizable comonomers which may optionally be used include, for example, aromatic vinyl monomers (for example, styrene, ⁇ -methylstyrene, vinylpyridine, fluoroethyl vinyl ether, etc.), ⁇ , ⁇ -unsaturated carboxylic acids.
  • esters or amides of ⁇ , ⁇ -unsaturated carboxylic acids eg methyl (meth) acrylate, ethyl (meth) acrylate, n-dodecyl (meth) acrylate, methoxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, or polyethylene glycol (meth) acrylate
  • anhydrides of ⁇ , ⁇ -unsaturated dicarboxylic acids (For example, maleic anhydride, itaconic anhydride, citraconic anhydride, etc.), but is not limited thereto.
  • the partially hydrogenated nitrile rubber further comprises esters of ⁇ , ⁇ -unsaturated carboxylic acids as comonomers, such as (meth) acrylate based monomers.
  • esters of ⁇ , ⁇ -unsaturated carboxylic acids as comonomers
  • examples of the (meth) acrylate monomers include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, iso amyl acrylate, n-ethylhexyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, 2-hydroxyethyl methacrylate, or hydroxy Propyl methacrylate and the like.
  • the content ratio of repeating units of other copolymerizable comonomer-derived structures may vary within a wide range, in each case the total sum of repeating units of the structure is 100% by weight.
  • the content of the repeating unit of the ⁇ , ⁇ -unsaturated nitrile-derived structure is 20% based on the total weight of the partially hydrogenated nitrile rubber. It may be 50% to 50% by weight, more specifically 20% to 30% by weight.
  • the repeating unit having an ⁇ , ⁇ -unsaturated nitrile-derived structure is included in the above content range, the dispersibility of the conductive material can be increased, and even if the amount of the conductive material added is small, high conductivity can be given.
  • the content of the repeating unit of the ⁇ , ⁇ -unsaturated nitrile-derived structure in the partially hydrogenated nitrile rubber is the weight ratio of the entire rubber of the repeating unit of the structure derived from the ⁇ , ⁇ -unsaturated nitrile.
  • the measurement of is the median of the value which measures the amount of nitrogen which generate
  • the partially hydrogenated nitrile rubber is 20% to 70% by weight, more specifically 20% to 50% by weight, and more specifically, the repeating unit of the hydrogenated conjugated diene-derived structure As may be included in 30% by weight to 50% by weight.
  • the repeating unit of the hydrogenated conjugated diene-derived structure in the content range as described above, the miscibility to the dispersion medium can be increased to increase the dispersibility of the carbon-based material.
  • the content ratio may vary depending on the type and nature of the comonomer, but specifically, the content of the repeating unit of the comonomer-derived structure may be partially hydrogenated. It may be 30% by weight or less, more specifically 10% to 30% by weight relative to the total weight of the nitrile rubber.
  • the partially hydrogenated nitrile rubber includes repeating units of the structure of Formula 1, repeating units of the structure of Formula 2, and repeating units of the structure of Formula 3, and optionally, ⁇ , ⁇ -unsaturated carbon It may be an acrylonitrile-butadiene rubber (H-NBR) further comprising a repeating unit of the ester-derived structure of the acid.
  • H-NBR acrylonitrile-butadiene rubber
  • the content of the repeating unit of the acrylonitrile-derived structure of Formula 1 may be 20% to 50% by weight relative to the total weight of the rubber.
  • the content of the repeating unit of the hydrogenated butadiene-derived structure of Formula 3 may be 20% to 50% by weight relative to the total weight of the rubber.
  • the content of the repeating unit of the ⁇ , ⁇ - unsaturated carboxylic acid ester of the structure is derived rubber
  • the total weight may be 30% by weight or less, more specifically 10% by weight to 30% by weight.
  • the partially hydrogenated nitrile rubber may have a weight average molecular weight of 10,000 g / mol to 700,000 g / mol, more specifically 10,000 g / mol to 200,000 g / mol.
  • the partially hydrogenated nitrile rubber may have a polydispersity index PDI (ratio of Mw / Mn, Mw is weight average molecular weight and Mn is number average molecular weight) in the range of 2.0 to 6.0, specifically, 2.0 to 4.0. have.
  • the conductive material can be uniformly dispersed in the dispersion medium by satisfying the average particle size condition of the conductive material-dispersant composite.
  • the weight average molecular weight and the number average molecular weight are polystyrene reduced molecular weights analyzed by gel permeation chromatography (GPC).
  • the partially hydrogenated nitrile rubber may have a Mooney viscosity (ML 1 + 4 at 100 ° C.) of 10 to 120, more specifically 10 to 100.
  • the Mooney viscosity of the partially hydrogenated nitrile rubber in the present invention can be measured according to ASTM standard D 1646.
  • the positive electrode active material is a compound capable of reversible intercalation and deintercalation of lithium (lithiated intercalation compound), specifically Is a material having a hexagonal layered rock salt structure (specifically, LiCoO 2 , LiCo 1/3 Mn 1/3 Ni 1/3 O 2 , or LiNiO 2 ), a material having an olivine structure (specifically, LiFePO 4 ), A spinel material having a cubic structure (specifically, LiMn 2 O 4 ), and other vanadium oxides such as V 2 O 5 , and a chalcone compound such as TiS or MoS.
  • lithium lithiumated intercalation compound
  • the cathode active material may be a lithium composite metal oxide including a metal such as cobalt, manganese, nickel or aluminum and lithium.
  • the lithium composite metal oxide is specifically, a lithium-manganese oxide (eg, LiMnO 2 , LiMn 2 O Etc.), lithium-cobalt-based oxides (e.g., LiCoO 2, etc.), lithium-nickel-based oxides (e.g., LiNiO 2, etc.), lithium-nickel-manganese-based oxides (e.g., LiNi 1 - Y Mn Y O 2 (where, 0 ⁇ Y ⁇ 1), LiMn 2-z Ni z O 4 (where, 0 ⁇ z ⁇ 2) and the like), lithium-nickel-cobalt-based oxide (for example, LiNi 1- Y Co Y O 2 (where, 0 ⁇ Y ⁇ 1) and the like), lithium-manganese-cobalt oxide (e.g., LiCo 1-Y M
  • the cathode active material may be a lithium composite metal oxide having a layered structure, and more specifically, may be a lithium cobalt oxide having a layered structure.
  • the metal elements except lithium is selected from the group consisting of Al, Cu, Fe, V, Cr, Ti, Zr, Zn, Ta, Nb, Mg, B, W, and Mo. It may be doped by any one or two or more elements selected. As described above, when the above metal element is further doped into the lithium composite metal oxide of the lithium defect, the structural stability of the cathode active material may be improved, and as a result, the output characteristics of the battery may be improved. In this case, the content of the doping element included in the lithium composite metal oxide may be appropriately adjusted within a range that does not lower the characteristics of the positive electrode active material, specifically, may be 0.02 atomic% or less.
  • the lithium composite metal oxide may include a compound of Formula 4 below:
  • M is one containing one or two or more elements selected from the group consisting of Al, Cu, Fe, V, Cr, Ti, Zr, Zn, Ta, Nb, Mg, B, W and Mo
  • a, x, y, z and w are each independently atomic fractions of the corresponding elements, -0.5 ⁇ a ⁇ 0.5, 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1, 0 ⁇ z ⁇ 1, 0 ⁇ w ⁇ 1 and 0 ⁇ x + y + z ⁇ 1.
  • the positive electrode active material is 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1, 0 ⁇ z ⁇ 1 in Formula 4, It may include a compound of y + z ⁇ x, more specifically, the positive electrode active material is LiNi 0 . 6 Mn 0 . 2 Co 0 . 2 O 2 , LiNi 0 . 5 Mn 0 . 3 Co 0 . 2 O 2 , LiNi 0.7 Mn 0.15 Co 0.15 O 2 or LiNi 0 . 8 Mn 0 . 1 Co 0 . 1 O 2 and the like, any one or a mixture of two or more thereof may be used.
  • composition for forming an anode according to an embodiment of the present invention may optionally further include a binder.
  • the binder serves to improve adhesion between the cathode active material particles and adhesion between the cathode active material and the current collector.
  • Specific examples include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC), Starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene butadiene rubber (SBR), fluororubber Or various copolymers thereof, and the like may be used alone or in a mixture of two or more thereof.
  • the binder may be included in an amount of 1% to 30% by weight based on the total weight of solids in the composition for forming an
  • composition for forming a cathode according to an embodiment of the present invention having the above composition may be prepared by dissolving and dispersing a cathode active material, a conductive material, a dispersant and optionally a binder in a solvent by mixing. Accordingly, the positive electrode forming composition may further include a solvent.
  • the solvent may be used without particular limitation as long as it is usually used in the preparation of the composition for forming an anode.
  • the solvent is an amide polar organic solvent such as dimethylformamide (DMF), diethyl formamide, dimethyl acetamide (DMAc) or N-methyl pyrrolidone (NMP); Methanol, ethanol, 1-propanol, 2-propanol (isopropyl alcohol), 1-butanol (n-butanol), 2-methyl-1-propanol (isobutanol), 2-butanol (sec-butanol), 1-methyl Alcohols such as 2-propanol (tert-butanol), pentanol, hexanol, heptanol or octanol; Glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,5-pentaned
  • the content of the positive electrode active material, the conductive material, the dispersant, the solvent, and optionally the binder may improve the processability and positive electrode characteristics at the time of manufacturing the positive electrode. It may be appropriately determined depending on the like.
  • the conductive material including the carbonaceous material for uniform dispersion of the conductive material in the positive electrode forming composition may be included in an amount of 0.1% to 10% by weight relative to the total weight of solids in the positive electrode forming composition.
  • the conductive material can exhibit a good balance of electronic conductivity and dispersibility. If the content of the conductive material is less than 0.1% by weight out of the above range, for example, when forming the electrode of a lithium secondary battery, the composition for forming an electrode includes a large amount of organic solvent, and as a result, the voids in the electrode increase, and the active material filling rate is increased. The battery capacity can be lowered by being lowered.
  • the drying time for removing the organic solvent may be long.
  • content of an electrically conductive material exceeds 10 weight%, there exists a possibility that a dispersibility may fall.
  • the conductive material including the carbonaceous material may be included in an amount of 0.1% by weight to 2% by weight based on the total weight of solids in the composition for forming an anode.
  • the dispersant may be included in 10 parts by weight to 50 parts by weight with respect to 100 parts by weight of the conductive material. If the content of the dispersant is less than 10 parts by weight, it is difficult to uniformly disperse the conductive material in the dispersion. If the content of the dispersant is more than 50 parts by weight, the viscosity of the composition may increase, leading to a decrease in processability.
  • the dispersant may be included in an amount of 0.1% to 10% by weight based on the total weight of solids in the composition for forming the positive electrode. If the content of the dispersant is less than 0.1% by weight, the effect of improving the dispersibility of the conductive material according to the use of the dispersant may be insignificant. If the content of the dispersant is more than 10% by weight, there is a concern that the capacity characteristics of the battery may be deteriorated due to the increase in the anode resistance and the decrease of the relative active material. There may be.
  • the cathode active material may be included in an amount of 80% by weight to 98% by weight based on the total weight of solids in the composition for forming an anode. If the content of the positive electrode active material is less than 80% by weight, the capacity characteristics may be lowered. If the content of the positive electrode active material is more than 98% by weight, the battery characteristics may be deteriorated due to the relative decrease of the content of the conductive material and the dispersant.
  • the solvent may be included in an amount such that the composition for forming the positive electrode has an appropriate viscosity to enable easy application and uniform coating during application of the composition for forming the positive electrode.
  • the positive electrode forming composition according to an embodiment of the present invention may further include a dispersion stabilizer for increasing the dispersion stability of the conductive material.
  • the dispersion stabilizer may prevent the agglomeration of carbon black by adsorbing the surface of the conductive material to exhibit a lapping effect surrounding the conductive material. Accordingly, the dispersion stabilizer may be excellent in affinity for the conductive material and at the same time excellent in miscibility with the dispersant and the solvent. Specifically, the dispersion stabilizer may be polyvinylpyrrolidone or the like.
  • the dispersion stabilizer may be a weight average molecular weight of 20,000g / mol to 5,000,000g / mol. If the molecular weight of the dispersion stabilizer is too small, less than 20,000 g / mol, it is difficult to exhibit a sufficient lapping effect for carbon black, and if the molecular weight is too large, exceeding 5,000,000 g / mol, the molecular motion of the dispersion stabilizer in the dispersion medium may be reduced. It is hard to wrap carbon black enough. More specifically, the dispersion stabilizer may have a weight average molecular weight of 70,000 g / mol to 2,000,000 g / mol.
  • the dispersion stabilizer may be used in 1 to 10 parts by weight with respect to 100 parts by weight of the conductive material. If the content of the dispersion stabilizer is too low compared to the content of the conductive material, it is difficult to obtain a sufficient lapping effect, and as a result, there is a fear that aggregation between the conductive materials occurs.
  • the composition for forming a positive electrode according to an embodiment of the present invention having the above composition comprises the steps of preparing a conductive material dispersion by milling a mixture of the conductive material and the dispersant in a solvent (step 1); And adding and mixing a cathode active material, and optionally a binder and other additives to the conductive material dispersion (step 2).
  • the conductive material comprises a carbon-based material having a specific surface area of 130 m 2 / g or more, oil absorption of 220 ml / 100 g or more of 0.1% by weight to 2% by weight relative to the total weight of solids in the composition for forming an anode
  • the conductive material dispersion includes a conductive material-dispersant composite in which the dispersant is introduced into the conductive material, and the conductive material-dispersant composite has a D 50 of a particle size distribution of 0.8 ⁇ m to 1.2 ⁇ m.
  • a first step for preparing a composition for forming an anode according to an embodiment of the present invention is preparing a conductive material dispersion.
  • the conductive material dispersion may be prepared by specifically preparing a mixture by mixing the conductive material and the dispersant in a solvent and then milling it.
  • the mixing process may be performed by a conventional mixing or dispersing method, and specifically, may be performed by a homogenizer, a bead mill, a ball mill, a basket mill, an attention mill, a universal stirrer, a clear mixer, or a TK mixer. have.
  • the milling process may be performed using a conventional milling method such as a ball mill, a bead mill, a basket mill, and more specifically, a bead mill.
  • a conventional milling method such as a ball mill, a bead mill, a basket mill, and more specifically, a bead mill.
  • the dispersibility of the conductive material and the dispersion particle size of the conductive material-dispersant composite may vary depending on the conditions such as the diameter and filling rate of the bead mill, the rotational speed of the rotor, the discharge speed of the conductive material dispersion during the milling process, It is preferable to carry out at the milling conditions optimized according to the kind and content of the electrically conductive material and dispersing agent used.
  • the milling process according to the use of the conductive material and the dispersant as described above may be a diameter of the bead mill 0.5mm to 2mm, More specifically, it may be 0.7mm to 1.5mm.
  • the filling rate of the bead mill may be 50% to 90% by weight, and more specifically 80% to 90% by weight relative to the total weight of the conductive material dispersion.
  • the circumferential speed during the bead mill process may be 6 m / s to 12 m / s, more specifically 7 m / s to 12 m / s.
  • the discharge rate of the mixture may be 0.5 kg / min to 1.5 kg / min, more specifically 0.5 kg / min to 1 kg / min under the conditions that meet all the bead mill process conditions.
  • the discharge rate of the conductive material dispersion is out of the above range, the conductive material-dispersant composite particle size distribution conditions in the composition for forming an anode may not be satisfied, and as a result, the effect of the present invention may be insignificant due to the decrease in the dispersibility of the conductive material.
  • the second step for producing a composition for forming a positive electrode according to an embodiment of the present invention is a positive electrode active material, and optionally a binder and other additives to the conductive material dispersion prepared in step 1 to add and mix the positive electrode It is a step of preparing a composition for forming.
  • the mixing process may be carried out by a conventional mixing or dispersing method, specifically, homogenizer, bead mill, ball mill, basket mill, attrition mill, universal stirrer, clear mixer or TK mixer Can be performed by
  • a positive electrode forming composition in which a positive electrode active material, a conductive material, and a dispersant is uniformly dispersed in a solvent is prepared.
  • the conductive material and the dispersant may be included in a dispersant is dispersed in the form of a conductive material-dispersant composite introduced into the surface of the conductive material through a physical or chemical bond.
  • the conductive material-dispersant composite may have a distribution in which D 50 of the particle size distribution is 0.8 ⁇ m to 1.2 ⁇ m and D 90 is 2.0 ⁇ m to 5.0 ⁇ m or less.
  • the particle size distributions D 50 and D 90 of the conductive material-dispersant composite may be defined as particle diameters based on 50% and 90% of the particle size distribution, respectively.
  • the particle size distribution D 50 of the complex can be measured using, for example, a laser diffraction method, and more specifically, a commercially available laser diffraction particle size measuring apparatus after dispersing the complex in a solvent. after examining the ultrasound of about 28kHz is introduced (for example Microtrac MT 3000) to the output 60 W, it is possible to calculate the average particle diameter (D 50) of from 50% based on the particle size distribution of the measuring device.
  • the composition for forming an anode according to the exemplary embodiment of the present invention is a uniform dispersion of a conductive material having excellent conductivity, and thus may exhibit excellent conductivity throughout the electrode when manufacturing the electrode. In addition, performance such as capacity characteristics and rate characteristics can be greatly improved.
  • a positive electrode manufactured using the positive electrode forming composition is provided.
  • that the positive electrode is manufactured using the positive electrode forming composition described above means that the positive electrode forming composition, a dried material thereof, or a cured product thereof is included.
  • the positive electrode according to an embodiment of the present invention may be manufactured according to a conventional method except for forming a positive electrode active material layer using the positive electrode forming composition. Specifically, the positive electrode is applied to the positive electrode current collector and the composition for forming the positive electrode and dried; Alternatively, the composition for forming the cathode may be cast on a separate support, and then the film obtained by peeling from the support may be manufactured by laminating on a cathode current collector.
  • the positive electrode manufactured according to the above-described manufacturing method includes a positive electrode current collector and a positive electrode active material layer on the positive electrode current collector, in which a composite of a conductive material-dispersant is uniformly dispersed.
  • the positive electrode current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery.
  • copper, stainless steel, aluminum, nickel, titanium, calcined carbon, or carbon on the surface of aluminum or stainless steel Surface treated with nickel, titanium, silver, or the like may be used.
  • the current collector may have a thickness of typically 3 ⁇ m to 500 ⁇ m, and may form fine irregularities on the surface of the current collector to increase adhesion of the positive electrode active material.
  • it can be used in various forms, such as a film, a sheet, a foil, a net, a porous body, a foam, a nonwoven body.
  • an electrochemical device including the anode is provided.
  • the electrochemical device may be specifically a battery, a capacitor, or the like, and more specifically, a lithium secondary battery.
  • the lithium secondary battery specifically includes a positive electrode, a negative electrode positioned to face the positive electrode, a separator and an electrolyte interposed between the positive electrode and the negative electrode, and the positive electrode is as described above.
  • the lithium secondary battery may further include a battery container for accommodating the electrode assembly of the positive electrode, the negative electrode, and the separator, and a sealing member for sealing the battery container.
  • the negative electrode includes a negative electrode current collector and a negative electrode active material layer positioned on the negative electrode current collector.
  • the negative electrode active material layer may include at least one of a negative electrode active material and optionally a binder, a conductive material, and other additives.
  • the negative electrode active material is a compound capable of reversible intercalation and deintercalation of lithium, including carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon; Metallic compounds capable of alloying with lithium such as Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si alloys, Sn alloys or Al alloys; Metal oxides capable of doping and undoping lithium such as SiO x (0 ⁇ x ⁇ 2), SnO 2 , vanadium oxide, lithium vanadium oxide; Or an anode active material such as a composite including the metallic compound and a carbonaceous material, such as a Si-C composite or a Sn-C composite, and any one or a mixture of two or more thereof may be used.
  • carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon
  • Metallic compounds capable of alloying with lithium such as Si, Al, Sn, P
  • a metal lithium thin film may be used as the anode active material.
  • the carbon material both low crystalline carbon and high crystalline carbon can be used. Soft crystalline carbon and hard carbon are typical low crystalline carbon, and high crystalline carbon is amorphous, plate, scaly, spherical or fibrous natural graphite or artificial graphite, Kish graphite (Kish) graphite, pyrolytic carbon, mesophase pitch based carbon fiber, meso-carbon microbeads, mesophase pitches and petroleum or coal tar pitch High-temperature calcined carbon such as derived cokes is typical.
  • the binder and the conductive material are the same as described above for the positive electrode.
  • the separator is to separate the negative electrode and the positive electrode and to provide a passage for the movement of lithium ions, if it is usually used as a separator in a lithium secondary battery can be used without particular limitation, in particular to the ion movement of the electrolyte It is desirable to have a low resistance against the electrolyte and excellent electrolytic solution-moisture capability.
  • a porous polymer film for example, a porous polymer film made of a polyolefin-based polymer such as ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer and ethylene / methacrylate copolymer or the like Laminate structures of two or more layers may be used.
  • a porous nonwoven fabrics such as nonwoven fabrics made of high melting point glass fibers, polyethylene terephthalate fibers and the like may be used.
  • a coated separator containing a ceramic component or a polymer material may be used to secure heat resistance or mechanical strength, and may be optionally used as a single layer or a multilayer structure.
  • examples of the electrolyte used in the present invention include an organic liquid electrolyte, an inorganic liquid electrolyte, a solid polymer electrolyte, a gel polymer electrolyte, a solid inorganic electrolyte, a molten inorganic electrolyte, and the like, which can be used in manufacturing a lithium secondary battery. It doesn't happen.
  • the electrolyte may include an organic solvent and a lithium salt.
  • the organic solvent may be used without particular limitation as long as it can serve as a medium through which ions involved in the electrochemical reaction of the battery can move.
  • the organic solvent may be an ester solvent such as methyl acetate, ethyl acetate, ⁇ -butyrolactone or ⁇ -caprolactone; Ether solvents such as dibutyl ether or tetrahydrofuran; Ketone solvents such as cyclohexanone; Aromatic hydrocarbon solvents such as benzene and fluorobenzene; Dimethylcarbonate (DMC), diethylcarbonate (DEC), methylethylcarbonate (MEC), ethylmethylcarbonate (EMC), ethylene carbonate (EC), propylene carbonate, Carbonate solvents such as PC) and the like.
  • DMC dimethylcarbonate
  • DEC diethylcarbonate
  • MEC methylethylcarbonate
  • EMC ethylmethylcarbonate
  • EC ethylene carbonate
  • carbonate-based solvents are preferable, and cyclic carbonates having high ionic conductivity and high dielectric constant (for example, ethylene carbonate or propylene carbonate) that can improve the charge and discharge performance of a battery, and low viscosity linear carbonate compounds ( For example, a mixture of ethyl methyl carbonate, dimethyl carbonate or diethyl carbonate and the like is more preferable.
  • the lithium salt may be used without particular limitation as long as it is a compound capable of providing lithium ions used in a lithium secondary battery.
  • the lithium salt is LiPF 6 , LiClO 4 , LiAsF 6 , LiBF 4 , LiSbF 6 , LiAl0 4 , LiAlCl 4 , LiCF 3 SO 3 , LiC 4 F 9 SO 3 , LiN (C 2 F 5 SO 3 ) 2 , LiN (C 2 F 5 SO 2 ) 2 , LiN (CF 3 SO 2 ) 2 .
  • LiCl, LiI, or LiB (C 2 O 4 ) 2 and the like can be used.
  • the lithium salt is preferably included at a concentration of approximately 0.6 mol% to 2 mol% in the electrolyte.
  • the electrolyte includes, for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylene diamine, n for the purpose of improving battery life characteristics, suppressing battery capacity reduction, and improving battery discharge capacity.
  • -Glyme hexaphosphate triamide, nitrobenzene derivative, sulfur, quinone imine dye, N-substituted oxazolidinone, N, N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2
  • One or more additives such as -methoxy ethanol or aluminum trichloride may be included. In this case, the additive may be included in an amount of 0.1% to 5% by weight based on the total weight of the electrolyte.
  • the lithium secondary battery having the above configuration may be manufactured by manufacturing an electrode assembly through a separator between a positive electrode and a negative electrode, placing the electrode assembly inside a case, and then injecting an electrolyte solution into the case.
  • the electrode assembly may be stacked, and then impregnated in the electrolyte, and the resultant may be manufactured by sealing it in a battery case.
  • the lithium secondary battery including the cathode manufactured by using the composition for forming a cathode according to an embodiment of the present invention may stably exhibit excellent discharge capacity, output characteristics, and capacity retention rate due to uniform dispersion of the conductive material in the cathode. have.
  • portable devices such as a mobile telephone, a notebook computer, a digital camera, and the electric vehicle field
  • HEV hybrid electric vehicle
  • a battery module including the lithium secondary battery as a unit cell and a battery pack including the same are provided.
  • the battery module or the battery pack is a power tool (Power Tool); Electric vehicles including electric vehicles (EVs), hybrid electric vehicles, and plug-in hybrid electric vehicles (PHEVs); Or it can be used as a power source for any one or more of the system for power storage.
  • Power Tool Electric vehicles including electric vehicles (EVs), hybrid electric vehicles, and plug-in hybrid electric vehicles (PHEVs); Or it can be used as a power source for any one or more of the system for power storage.
  • NMP N-methylpyrrolidone
  • carbon black 135m 2 / g
  • OAN 220ml / 100g
  • dispersant partially hydrogenated nitrile rubber
  • Bead filling rate 80% by weight
  • Example 2 In the same manner as in Example 1, except that each component is used in the formulations described in Tables 1 to 3, and the discharge rate is 0.5 kg / min during the bead milling process for preparing the conductive material dispersion. It carried out to manufacture the composition for positive electrode formation.
  • Example 2 In the same manner as in Example 1, except that each component is used in the formulations described in Tables 1 to 3, and the discharge rate is 1.2 kg / min in the bead milling process for preparing the conductive material dispersion. It carried out to manufacture the composition for positive electrode formation.
  • Example 2 In the same manner as in Example 1 except that each component is used in the formulations described in Tables 1 to 3 below, and the discharge rate is 2 kg / min during the bead milling process for preparing the conductive material dispersion. To prepare a composition for forming an anode.
  • Example 2 In the same manner as in Example 1, except that each component is used in the formulations described in Tables 1 to 3, and the discharge rate is 0.3 kg / min during the bead milling process for preparing the conductive material dispersion. It carried out to manufacture the composition for positive electrode formation.
  • Example 1 Except for using each of the components in the formulation described in Tables 1 to 3, was carried out in the same manner as in Example 1 to prepare a composition for forming a positive electrode.
  • each component was used in the formulations described in Tables 1 to 3, except that polyvinyl alcohol (PVA) was used as the dispersant, and the composition for forming the anode was prepared in the same manner as in Example 1. .
  • PVA polyvinyl alcohol
  • Carbon black 30 135 220 Example 2 Carbon black 22 230 362 Example 3 Carbon black 26 170 272 Comparative Example 1 Carbon black 30 135 220 Comparative Example 2 Carbon black 30 135 220 Comparative Example 3 Carbon black 36 63 190 Comparative Example 4 Carbon black 30 135 220
  • AN is a repeating unit of acrylonitrile-derived structure in partially hydrogenated nitrile rubber
  • BD is a repeating unit of butadiene-derived structure
  • HBD is a repeating unit of hydrogenated butadiene-derived structure
  • BA is n-butylacryl It means the repeat unit of the rate-derived structure, the weight percent content of the repeat unit of each structure is a value based on the total weight of the partially hydrogenated nitrile rubber.
  • the positive electrode forming compositions prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were respectively coated on one surface of an aluminum foil, dried and rolled, and then punched to a predetermined size to prepare a positive electrode.
  • a negative electrode slurry was prepared by adding carbon powder as a negative electrode active material, carboxymethyl cellulose as a thickener, styrene-butadiene rubber as a binder, and carbon black as a conductive material, respectively, in a weight ratio of 96: 1: 2: 1.
  • the negative electrode slurry was applied to a thin copper (Cu) thin film, which is a negative electrode current collector having a thickness of 10 ⁇ m, and dried, followed by roll press to prepare a negative electrode.
  • Cu thin copper
  • a battery assembly was manufactured through a separator composed of three layers of polypropylene / polyethylene / polypropylene (PP / PE / PP) between the positive electrode and the negative electrode.
  • EMC ethyl methyl carbonate
  • DMC dimethyl carbonate
  • the particle size distribution of the conductive material was measured for the compositions for positive electrode formation prepared in Examples 1 to 3 and Comparative Examples 1 to 4 above.
  • Particle size The prepared positive electrode composition was diluted 500-fold using NMP solvent, and the D 50 and D 90 values of the particle size distribution of the carbon black-dispersant composite dispersed in the dispersion were measured using Malvern's Mastersizer 3000 equipment. It was. The results are shown in Table 4 below.
  • the carbon black-dispersant composite in the positive electrode composition of Examples 1 to 3 showed a more uniform particle size distribution than Comparative Example 1, and showed a larger particle size distribution than Comparative Example 2.
  • the particle size distribution was similar to that of Examples 1 to 3. This is because, in Comparative Examples 3 and 4, the milling was performed under the same conditions as in Example 1, and it was confirmed that the particle size distribution could be adjusted according to the milling conditions.
  • the resistance characteristics of the batteries prepared according to the above production examples were evaluated using the compositions for positive electrode formation prepared in Examples 1 to 3 and Comparative Examples 1 to 4 above.
  • the prepared lithium secondary battery was charged and discharged 1.0C / 1.0C three times at 25 ° C., and SOC (charge depth) was set based on the final discharge capacity.
  • SOC discharge depth
  • the 10 second resistance was measured by applying a discharge pulse at 6.5C at SOC15, SOC30 and SOC50, respectively. The results are shown in Table 5 below.
  • the rate characteristic was evaluated about the battery manufactured using the composition for positive electrode formation manufactured in the said Examples 1-3 and Comparative Examples 1-4.
  • two unit cells were prepared in the same manner as in Preparation Example using the compositions for forming anodes prepared in Example 1 and Comparative Examples 1 to 4, respectively, and the prepared unit cells were 0.1C at 25 ° C.
  • the battery was charged until the constant current (CC) of 4.25V, then charged with a constant voltage (CV) of 4.25V, and the first charge was performed until the charging current became 0.05mAh.
  • the battery was discharged to a constant current of 0.1C until 3.0V, and the discharge capacity of the first cycle was measured. Thereafter, the capacity characteristics for each rate were evaluated by varying the discharge conditions at 2.0C.
  • Rate capacity represents the ratio of the capacity
  • the specific surface area and the oil absorption amount is less than 130 m 2 / g and less than 220 ml / 100g, since the structure of the conductive material is less developed, the volume of the conductive material per weight is not small enough to cover the active material surface As a result, the cell performance was deteriorated.
  • Comparative Example 4 it was considered that by using PVA as a dispersant, the PVA was insulated or denatured from the positive electrode active material to deteriorate discharge characteristics, thereby degrading cell performance.
  • the prepared lithium secondary battery was charged at 1C to 4.25V under constant current / constant voltage (CC / CV) conditions at 45 ° C., and then discharged at 1C to 3.0V under constant current (CC) conditions. This cycle was repeated for 490 cycles, and the capacity retention rate at the 490th cycle was measured.
  • Table 7 The results are shown in Table 7 below.
  • Example 1 First cell 90.1 90.0 2nd cell 89.7
  • Example 2 First cell 89.8 89.7 2nd cell 89.5
  • Example 3 First cell 90.1 90.1 2nd cell 90.1 Comparative Example 1 First cell 83.5 86.0 2nd cell 88.4 Comparative Example 2 First cell 90.0 89.4 2nd cell 88.7 Comparative Example 3 First cell 84.1 84.5 2nd cell 84.8 Comparative Example 4 First cell 87.1 87.3 2nd cell 87.4
  • the battery containing the positive electrode produced by the composition for forming the positive electrode of Examples 1 to 3 exhibited a better high temperature capacity retention rate and the smallest cell variation. It is considered that the conductive materials included in Examples 1 to 3 form a dispersant and a conductive material-dispersant composite to stably exhibit excellent capacity retention by uniformly dispersing the conductive material in the positive electrode.

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  • Battery Electrode And Active Subsutance (AREA)

Abstract

La présente invention concerne une composition pour la formation d'une cathode d'accumulateur, et une cathode d'accumulateur et un accumulateur qui sont fabriqués à l'aide de cette composition, la composition comprenant un matériau actif de cathode, un matériau conducteur et un dispersant, le matériau conducteur contenant, sur la base du poids total de la composition pour la formation d'une cathode, de 0,1 à 2 % en poids d'un matériau à base de carbone ayant une surface spécifique supérieure ou égale à 130 m2/g et une quantité d'absorption d'huile supérieure ou égale à 220 ml/100 g, le dispersant étant introduit dans le matériau conducteur de manière à former un composite matériau conducteur-dispersant, et la valeur D50 de la distribution granulométrique du composite matériau conducteur-dispersant étant de 0,8 à 1,2 µm.
PCT/KR2017/003219 2016-03-24 2017-03-24 Composition pour la formation d'une cathode d'accumulateur, et cathode d'accumulateur et accumulateur fabriqués à l'aide de ladite composition Ceased WO2017164701A1 (fr)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US15/751,067 US10741829B2 (en) 2016-03-24 2017-03-24 Composition for forming positive electrode of secondary battery, positive electrode for secondary battery and secondary battery manufactured using the same
EP17770671.0A EP3331072B1 (fr) 2016-03-24 2017-03-24 Composition pour la formation d'une cathode d'accumulateur, et cathode d'accumulateur et accumulateur fabriqués à l'aide de ladite composition
CN201780002924.7A CN107949940B (zh) 2016-03-24 2017-03-24 用于形成二次电池的正极的组合物、正极及二次电池
JP2018515444A JP6636141B2 (ja) 2016-03-24 2017-03-24 二次電池の正極形成用組成物、及びこれを用いて製造した二次電池用正極並びに二次電池
PL17770671T PL3331072T3 (pl) 2016-03-24 2017-03-24 Kompozycja do utworzenia katody akumulatora, oraz katoda akumulatora i akumulator, który jest wytwarzany z jej użyciem

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR10-2016-0035562 2016-03-24
KR20160035562 2016-03-24
KR10-2017-0036956 2017-03-23
KR1020170036956A KR102143953B1 (ko) 2016-03-24 2017-03-23 이차전지의 양극 형성용 조성물 및 이를 이용하여 제조한 이차전지용 양극 및 이차전지

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WO2017164701A1 true WO2017164701A1 (fr) 2017-09-28

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US11121361B2 (en) 2017-03-23 2021-09-14 Lg Chem, Ltd. Method of preparing slurry for secondary battery positive electrode
CN118970056A (zh) * 2024-10-16 2024-11-15 浙江赞昇新材料有限公司 Hnbr作为锂离子电池正极粘结剂的应用、锂离子电池正极及锂离子电池

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JP5533057B2 (ja) * 2010-03-11 2014-06-25 東洋インキＳｃホールディングス株式会社 カーボンブラック分散液
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11121361B2 (en) 2017-03-23 2021-09-14 Lg Chem, Ltd. Method of preparing slurry for secondary battery positive electrode
CN118970056A (zh) * 2024-10-16 2024-11-15 浙江赞昇新材料有限公司 Hnbr作为锂离子电池正极粘结剂的应用、锂离子电池正极及锂离子电池

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