WO2014204214A1 - Binder solution for anode, active material slurry for anode comprising same, anode using said active material slurry, and electrochemical device comprising same - Google Patents

Binder solution for anode, active material slurry for anode comprising same, anode using said active material slurry, and electrochemical device comprising same Download PDF

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Publication number
WO2014204214A1
WO2014204214A1 PCT/KR2014/005376 KR2014005376W WO2014204214A1 WO 2014204214 A1 WO2014204214 A1 WO 2014204214A1 KR 2014005376 W KR2014005376 W KR 2014005376W WO 2014204214 A1 WO2014204214 A1 WO 2014204214A1
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Prior art keywords
anode
active material
binder
material slurry
binder solution
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PCT/KR2014/005376
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French (fr)
Korean (ko)
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양지혜
김장배
이병배
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주식회사 엘지화학
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Priority to CN201480034381.3A priority Critical patent/CN105308780B/en
Priority claimed from KR1020140074405A external-priority patent/KR20140147052A/en
Publication of WO2014204214A1 publication Critical patent/WO2014204214A1/en
Priority to US14/591,135 priority patent/US9515321B2/en

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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
    • H01M4/62—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
    • 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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • 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 binder solution, an anode active material slurry comprising the same, an anode using the active material slurry, and an electrochemical device comprising the same, and more particularly, to reduce volume expansion of an anode active material due to occlusion and release of lithium.
  • the present invention relates to an anode binder solution for improving durability of an anode to improve life characteristics of an electrochemical device, an anode active material slurry containing the same, an anode using the active material slurry, and an electrochemical device including the same.
  • the electrochemical device is the area that is receiving the most attention in this respect, and the development of a secondary battery capable of charging and discharging has been the focus of attention, and in recent years in the development of such a battery in order to improve the capacity density and specific energy R & D on the design of electrodes and batteries is underway.
  • lithium secondary batteries developed in the early 1990s have a higher operating voltage and greater energy density than conventional batteries such as Ni-MH, Ni-Cd, and sulfuric acid-lead batteries that use an aqueous electrolyte solution. I am in the spotlight.
  • Such electrochemical devices generally include a cathode, an anode, and a separator interposed between the cathode and the anode.
  • the cathode and the anode is dispersed on the surface of each current collector, the electrode active material, the polymer binder and the electrode active material, and coated with an electrode active material slurry containing a solvent for dissolving the polymer binder to dry the electrode active material layer Form.
  • the volume of the anode active material is increased by occluding and releasing lithium.
  • volume expansion may be further intensified.
  • cracks may be formed while the pore size formed on the surface of the anode active material layer increases, and the formation of the cracks causes the anode. Desorption of the active material layer may occur, thereby lowering the charge / discharge characteristics of the electrochemical device, which in turn lowers the life characteristics of the electrochemical device.
  • the problem to be solved by the present invention by reducing the volume expansion of the anode active material due to the occlusion and release of lithium due to the progress of the cycle of the electrochemical device, improve the durability of the anode active material layer to improve the life characteristics of the electrochemical device
  • Anode binder solution for improving the coating stability of the anode active material layer by further maintaining excellent dispersibility of the anode active material slurry, anode active material slurry comprising the same, anode using the active material slurry and electrochemical comprising the same It is to provide an element.
  • a thermal crosslinkable polymer binder crosslinked by heat; And a solvent for dissolving the thermally crosslinkable polymer binder.
  • a binder solution for an anode having a hydrogen ion concentration of pH 2.5 to pH 4.5, preferably pH 3.0 to pH 3.5 is provided.
  • the thermal crosslinkable polymer binder may include a carboxy group as a functional group.
  • the thermally crosslinkable polymer binder including a carboxyl group as a functional group may be polyacrylic acid.
  • the solvent may be acetone, tetra hydrofuran, methylene chloride, chloroform, dimethylform amide, N-methyl-2-pyrrolidone (N). -methyl-2-pyrrolidone, NMP), cyclohexane and any one selected from the group consisting of water or a mixture of two or more thereof.
  • anode binder solution may further include an aqueous binder.
  • the weight ratio of the thermally crosslinkable polymer binder and the aqueous binder may be 2: 8 to 5: 5, preferably 2: 8 to 4: 6.
  • the aqueous binder may include styrene butadiene rubber, carboxymethyl cellulose, polytetrafluoroethylene, polyethylene, polypropylene, ethylene propylene copolymer, polybutadiene, butyl rubber, fluorine rubber, polyethylene oxide, polyvinylpyrrolidone , Polyepichlorohydrin, polyphosphagen, polyacrylonitrile, polystyrene, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenolic resin, epoxy resin, polyvinyl It may be any one selected from the group consisting of alcohol and hydroxypropyl cellulose or a mixture of two or more thereof.
  • the binder solution for the anode And an anode active material dispersed in the anode binder solution, wherein the anode binder solution is provided with an anode active material slurry, wherein the anode binder solution of the present invention is described above.
  • the hydrogen ion concentration of the anode active material slurry may be pH 2.5 to pH 4.5, preferably pH 3.0 to pH 3.5.
  • the solid content of the anode active material slurry may be 43 to 50% by weight of the active material slurry for the anode.
  • the anode active material may include lithium metal, a carbon material, a metal compound, a metal oxide, or a mixture thereof.
  • the metal compound is Si, Ge, Sn, Pb, P, Sb, Bi, Al, Ga, In, Ti, Mn, Fe, Co, Ni, Cu, Zn, Ag, Mg, Sr, and Ba It may be any one selected from the group consisting of or a mixture of two or more thereof.
  • the metal oxide may be any one selected from the group consisting of silicon oxide, tin oxide, titanium oxide, and lithium vanadium oxide, or a mixture of two or more thereof.
  • the current collector On the other hand, according to another aspect of the invention, the current collector; And an anode active material layer formed on one surface or both surfaces of the current collector, and formed of a result of the drying step of the active material slurry for the anode of the present invention described above.
  • the thermal crosslinkable polymer binder can be crosslinked with each other to form a crosslinked polymer network.
  • the drying step to remove the solvent through the first drying at a temperature of 120 to 140 °C, may be to form the cross-linked polymer network through the secondary drying at a temperature of 140 to 160 °C in a vacuum state. .
  • the current collector And an anode active material layer formed on one or both surfaces of the current collector, wherein the anode active material layer comprises an anode active material and a polymer binder, and the polymer binder is a heat crosslinkable polymer that is crosslinked by heat.
  • the thermally crosslinkable polymer binder may be polyacrylic acid
  • the aqueous binder may be styrene butadiene rubber.
  • the anode in the electrochemical device comprising a cathode, an anode, a separator interposed between the cathode and the anode and the non-aqueous electrolyte, the anode is the electrochemical of the above-described anode of the present invention An element is provided.
  • the electrochemical device may be a lithium secondary battery.
  • the coating stability of the anode active material layer may be improved by maintaining the dispersibility of the active material slurry for the anode.
  • 1 is a graph showing viscoelastic properties of an active material slurry for anode according to Examples and Comparative Examples of the present invention.
  • Figure 2 is a SEM photograph showing the surface of the anode prepared according to an embodiment of the present invention.
  • Figure 3 is an anode prepared according to an embodiment of the present invention, a SEM photograph showing the surface after 70 cycles.
  • Figure 4 is a SEM photograph showing the surface of the anode prepared according to a comparative example of the present invention.
  • FIG. 6 is a graph comparing capacity retention rates for 70 cycles of coin-shaped half cells prepared according to one embodiment and one comparative example of the present invention.
  • the binder solution for the anode according to the present invention comprises a thermal crosslinkable polymer binder crosslinked by heat; And a solvent for dissolving the thermally crosslinkable polymer binder, wherein the hydrogen ion concentration is pH 2.5 to pH 4.5, preferably pH 3.0 to pH 3.5.
  • the anode active material slurry according to the present invention is an anode binder solution; And an anode active material dispersed in the anode binder solution; wherein the anode binder solution is an anode binder solution according to the present invention.
  • the hydrogen ion concentration of the anode active material slurry may be pH 2.5 to pH 4.5, preferably pH 3.0 to pH 3.5.
  • the anode active material used to be applied to the anode of the electrochemical device generates volume expansion upon occlusion and release of lithium.
  • volume expansion may be further intensified.
  • cracks may be formed while the pore size formed on the surface of the anode active material layer increases, and the formation of such cracks causes desorption of the anode active material layer.
  • the conductivity between the active material and the current collector is lowered, and the conductivity between the anode active material is lowered, thereby lowering the charge / discharge characteristics of the electrochemical device, which in turn lowers the life characteristics of the electrochemical device.
  • a heat crosslinkable polymer binder crosslinked by heat is used as the polymer binder used in the production of the anode.
  • the thermally crosslinkable polymer binder When the anode active material slurry including the thermally crosslinkable polymer binder is applied to at least one surface of a current collector and then dried, the thermally crosslinkable polymer binder is crosslinked with each other to form a crosslinked polymer network, and the crosslinked polymer network is an active material layer.
  • the binder solution and the active material slurry dispersibility may be expressed by expressing a liquid behavior having a very high viscosity compared to elasticity. Maintained to be excellent to improve the coating stability of the anode active material layer.
  • the solid amount of the active material slurry for the anode may be 43 to 50% by weight of the active material slurry for the anode.
  • an appropriate viscosity of the active material slurry for the anode may be maintained and uniformly coated on the current collector, and the amount of moisture to be dried is not excessive so that the drying time can be properly maintained.
  • the thermally crosslinkable polymer binder may be one containing a carboxyl group as a functional group. Since the carboxyl group is crosslinked by heat, it forms anhydrous carboxylic anhydride groups other than hydrogen bonds between molecules, so that the linear polymer chain may be partially changed into a crosslinked polymer network to mitigate volume expansion of the anode active material.
  • the thermally crosslinkable polymer binder including a carboxyl group as a functional group may be polyacrylic acid.
  • the weight average molecular weight of the polyacrylic acid may be 400,000 to 800,000, but is not limited thereto.
  • the anode binder solution may further include an aqueous binder.
  • the weight ratio of the thermal crosslinkable polymer binder and the aqueous binder may be 2: 8 to 5: 5, preferably 2: 8 to 4: 6.
  • the weight ratio of the aqueous binder exceeds the upper limit of the numerical range, the mechanical properties of the electrode active material layer may be improved, but there is a concern that the resistance of the electrode active material layer may be increased.
  • the weight ratio of the thermally crosslinkable polymer binder exceeds the upper limit of the numerical range, the mechanical properties of the electrode active material layer may decrease, and the stability of the electrode active material slurry may decrease. Therefore, when the weight ratio is satisfied, an appropriate amount of the crosslinked polymer network is formed, thereby alleviating the volume expansion of the anode active material layer.
  • the water-based binder refers to a water-soluble or water-dispersible binder polymer, styrene butadiene rubber, carboxymethyl cellulose, polytetrafluoroethylene, polyethylene, polypropylene, ethylene propylene copolymer, polybutadiene, butyl rubber , Fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphagen, polyacrylonitrile, polystyrene, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin , Acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol and hydroxypropyl cellulose may be any one selected from the group consisting of or a mixture of two or more thereof.
  • anode active material may be a conventional anode active material that can be used in the anode of the conventional electrochemical device, in particular may include lithium metal, carbon material, metal compounds, metal oxides or mixtures thereof. have.
  • a lithium adsorption material such as carbon, petroleum coke, activated carbon, graphite, or other carbons may be used.
  • the metal compound may be Si, Ge, Sn, Pb, P, Sb, Bi, Al, Ga, In, Ti, Mn, Fe, Co, Ni, Cu, Zn, Ag, Mg, Sr, and Ba. It may be any one selected from the group consisting of or a mixture of two or more thereof.
  • the metal oxide may be any one selected from the group consisting of silicon oxide, tin oxide, titanium oxide, and lithium vanadium oxide, or a mixture of two or more thereof.
  • the solvent may be acetone, tetra hydrofuran, methylene chloride, chloroform, dimethylform amide, N-methyl-2-pyrrolidone (N). -methyl-2-pyrrolidone, NMP), cyclohexane, and any one selected from the group consisting of water or a mixture of two or more thereof, but is not limited thereto.
  • the solvent may be removed in the manufacturing process of the electrochemical device, since the solvent may cause various side reactions when remaining in the finally manufactured electrochemical device.
  • the current collector On the other hand, according to an aspect of the present invention, the current collector; And an anode active material layer formed on one surface or both surfaces of the current collector, and formed of a result of the drying step of the active material slurry for the anode of the present invention described above.
  • non-limiting examples of the current collector include a foil made by copper, gold, nickel or a copper alloy or a combination thereof.
  • the drying step the solvent is removed, the thermal crosslinkable polymer binder can be cross-linked with each other to form a crosslinked polymer network, wherein the drying step, the first drying at a temperature of 120 to 140 °C The solvent may be removed, and the crosslinked polymer network may be formed through secondary drying at a temperature of 140 to 160 ° C. in a vacuum state.
  • the current collector And an anode active material layer formed on one or both surfaces of the current collector, wherein the anode active material layer comprises an anode active material and a polymer binder, and the polymer binder is a heat crosslinkable polymer that is crosslinked by heat.
  • the weight ratio of the thermally crosslinkable polymer binder and the aqueous binder if the weight ratio of the aqueous binder exceeds the upper limit of the numerical range, the mechanical properties of the electrode active material layer can be improved, but the resistance of the electrode active material layer There is a fear of increasing.
  • the weight ratio of the thermally crosslinkable polymer binder exceeds the upper limit of the numerical range, the mechanical properties of the electrode active material layer may decrease, and the stability of the electrode active material slurry may decrease. Therefore, when the weight ratio is satisfied, an appropriate amount of the crosslinked polymer network is formed, thereby alleviating the volume expansion of the anode active material layer.
  • the thermally crosslinkable polymer binder may be polyacrylic acid
  • the aqueous binder may be styrene butadiene rubber.
  • the anode in the electrochemical device comprising a cathode, an anode, a separator interposed between the cathode and the anode and the non-aqueous electrolyte, is characterized in that the anode of the present invention described above An electrochemical device is provided.
  • the electrochemical device of the present invention includes all devices that perform an electrochemical reaction, and specific examples include capacitors such as all kinds of primary, secondary, fuel, solar, or supercapacitor devices.
  • capacitors such as all kinds of primary, secondary, fuel, solar, or supercapacitor devices.
  • a lithium secondary battery including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery or a lithium ion polymer secondary battery among the secondary batteries is preferable.
  • the electrochemical device according to the present invention may perform stacking, lamination, folding, and stacking / folding processes of the separator and the electrode.
  • the external shape of the electrochemical device is not particularly limited, but may be cylindrical, square, pouch or coin type using a can.
  • the cathode to be applied to the electrochemical device according to the present invention is not particularly limited, and the cathode active material may be manufactured in a form bound to the current collector according to conventional methods known in the art.
  • Non-limiting examples of the cathode active material may be a conventional cathode active material that can be used for the cathode of the conventional electrochemical device, in particular lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron oxide or a combination of these lithium composites Oxides can be used.
  • non-limiting examples of the cathode current collector is a foil produced by aluminum, nickel or a combination thereof.
  • the separator used in the present invention can be used as long as it is a porous substrate commonly used in the art, for example, a polyolefin-based porous membrane (membrane) or non-woven fabric may be used, but is not particularly limited thereto.
  • polyolefin-based porous membrane examples include polyethylene, polypropylene, polybutylene, polypentene, such as high density polyethylene, linear low density polyethylene, low density polyethylene, ultra high molecular weight polyethylene, respectively, or a mixture thereof
  • polyolefin-based polymers such as polyethylene, polypropylene, polybutylene, polypentene, such as high density polyethylene, linear low density polyethylene, low density polyethylene, ultra high molecular weight polyethylene, respectively, or a mixture thereof
  • polyethylene such as polyethylene, polypropylene, polybutylene, polypentene, such as high density polyethylene, linear low density polyethylene, low density polyethylene, ultra high molecular weight polyethylene, respectively, or a mixture thereof
  • polypentene such as high density polyethylene, linear low density polyethylene, low density polyethylene, ultra high molecular weight polyethylene, respectively, or a mixture thereof
  • the nonwoven fabric may be, for example, polyethylene terephthalate, polybutyleneterephthalate, polyester, polyacetal, polyamide, polycarbonate, or polycarbonate. ), Polyimide, polyetheretherketone, polyethersulfone, polyphenyleneoxide, polyphenylenesulfide, polyethylenenaphthalene, etc., alone or separately
  • the nonwoven fabric formed from the polymer which mixed these is mentioned.
  • the structure of the nonwoven can be a spunbond nonwoven or melt blown nonwoven composed of long fibers.
  • the thickness of the porous substrate is not particularly limited, but may be 5 ⁇ m to 50 ⁇ m, and the pore size and pore present in the porous substrate are also not particularly limited, but may be 0.01 ⁇ m to 50 ⁇ m and 10 to 95%, respectively.
  • At least one surface of the porous substrate may further include a porous coating layer including inorganic particles and a polymer binder.
  • the inorganic particles are not particularly limited as long as they are electrochemically stable. That is, the inorganic particles that can be used in the present invention are not particularly limited as long as the oxidation and / or reduction reactions do not occur in the operating voltage range (for example, 0 to 5 V on the basis of Li / Li + ) of the applied electrochemical device.
  • the ionic conductivity of the electrolyte may be improved by contributing to an increase in the dissociation degree of the electrolyte salt, such as lithium salt, in the liquid electrolyte.
  • the polymer binder may be polyvinylidene fluoride-hexafluorofluoropropylene (polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP)), polyvinylidene fluoride-chlorotrifluorofluoroethylene (polyvinylidene fluoride-co -chlorotrifluoroethylene, polyvinylidene fluoride-co-trichloroethylene, polymethylmethacrylate, polybutylacrylate, polyacrylonitrile, polyvinyl Pyrrolidone (polyvinylpyrrolidone), polyvinylacetate, ethylene vinyl-co-vinyl acetate, polyethylene, polyethylene oxide, polyarylate, cellulose acetate ( cellulose acetate), cellulose acetate butyrate, Cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinylalcohol
  • the polymer binder is coated on a part or the entire surface of the inorganic particles, and the inorganic particles are connected and fixed to each other by the polymer binder in close contact with each other, and an empty space existing between the inorganic particles. Due to the pores are preferably formed. That is, the inorganic particles of the porous coating layer are in close contact with each other, and the empty space generated when the inorganic particles are in close contact with the pores of the porous coating layer.
  • the size of the void space present between the inorganic particles is preferably equal to or smaller than the average particle diameter of the inorganic particles.
  • the electrolyte salt contained in the nonaqueous electrolyte solution that can be used in the present invention is a lithium salt.
  • the lithium salt may be used without limitation those conventionally used in the lithium secondary battery electrolyte.
  • organic solvent included in the nonaqueous electrolyte described above those conventionally used in the lithium secondary battery electrolyte may be used without limitation, and for example, ethers, esters, amides, linear carbonates, and cyclic carbonates may be used alone or in combination of two or more. It can be mixed and used.
  • carbonate compounds which are typically cyclic carbonates, linear carbonates, or mixtures thereof may be included.
  • cyclic carbonate compound examples include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, vinylene carbonate, vinylethylene carbonate and any one selected from the group consisting of halides thereof or mixtures of two or more thereof.
  • halides include, for example, fluoroethylene carbonate (FEC), but are not limited thereto.
  • linear carbonate compounds may be any one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethylmethyl carbonate (EMC), methylpropyl carbonate and ethylpropyl carbonate. Mixtures of two or more of them may be representatively used, but are not limited thereto.
  • ethylene carbonate and propylene carbonate which are cyclic carbonates among the carbonate-based organic solvents, are high viscosity organic solvents and have a high dielectric constant, so that they can dissociate lithium salts in the electrolyte better, and cyclic carbonates such as dimethyl carbonate and diethyl carbonate.
  • cyclic carbonates such as dimethyl carbonate and diethyl carbonate.
  • any one selected from the group consisting of dimethyl ether, diethyl ether, dipropyl ether, methylethyl ether, methylpropyl ether, and ethylpropyl ether, or a mixture of two or more thereof may be used. It is not limited to this.
  • esters in the organic solvent include methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, ⁇ -butyrolactone, ⁇ -valerolactone, ⁇ -caprolactone, ⁇ -valerolactone and One or a mixture of two or more selected from the group consisting of ⁇ -caprolactone may be used, but is not limited thereto.
  • the injection of the nonaqueous electrolyte may be performed at an appropriate step in the manufacturing process of the electrochemical device, depending on the manufacturing process and the required physical properties of the final product. That is, it may be applied before the electrochemical device assembly or the final step of the electrochemical device assembly.
  • anode active material a mixture of KSC1064 (SiO: C, Shin-Etsu Co., Ltd.) and MAG-V2 (artificial graphite / natural graphite mixture, Hitachi Chemical Co., Ltd.) (weight ratio of KSC1064 and MAG-V2 is 1: 2) was used.
  • binder polyacrylic acid (Sigma Aldrich) having a weight average molecular weight of about 450,000 and a styrene butadiene rubber as an aqueous binder were used, and carbon nanotubes were mixed as a conductive material, and an anode active material slurry having a pH of 3.3 was used.
  • the anode active material, the binder and the conductive material were mixed in a weight ratio of 90: 7: 3, the binder was adjusted so that the weight ratio of styrene butadiene rubber and polyacrylic acid is 7: 3.
  • An anode active material slurry was prepared in the same manner as in Example 1 except that the hydrogen ion concentration of the anode active material slurry was pH 7.3.
  • An anode active material slurry was prepared in the same manner as in Example 1 except that carboxymethyl cellulose was used as the polymer binder.
  • 1 is a graph showing viscoelastic properties of an active material slurry for anode according to Examples and Comparative Examples of the present invention.
  • Example 1-1 the elasticity of the solid phase is stronger than that of the viscosity, whereas in Example 1-1, the viscosity is low according to the shear rate and the viscosity is higher than the elasticity. Since it exhibits very high liquid phase behavior, it can be said that the dispersibility of Example 1-1 is the best.
  • the anode active material slurry prepared in Example 1-1 was coated on a copper (Cu) foil current collector in a conventional manner to prepare an anode.
  • a coin-type half cell was prepared using an electrode assembly made of a polyethylene porous membrane interposed between the anode and the lithium metal.
  • a coin-type half cell was prepared in the same manner as in Example 1-2 except for using the anode active material slurry prepared in Comparative Example 1-1 as the anode active material slurry.
  • a coin-type half cell was prepared in the same manner as in Example 1-2 except for using the anode active material slurry prepared in Comparative Example 2-1 as the anode active material slurry.
  • the capacity was measured under continuous charge and discharge conditions. Then, the surface of the anode was observed through SEM to confirm the degree of degradation of the anode before and after the cycle.
  • FIGS. 4 and 5 show the initial anode prepared according to Comparative Example 2-2 and 70 respectively. The anode surface after the cycle is shown.
  • Comparative Example 2-2 it was confirmed that the crack length is long during the course of the cycle due to small pores or small cracks already formed before the cycle.
  • Example 1-2 the size of the pores or cracks is formed smaller than that of Comparative Example 2-2, and the change in the size of the cracks was significantly smaller during the cycle, and rather the size of the pores was smaller. I could confirm it.
  • Example 2-2 the stress due to the volume expansion of the anode active material with the progress of the cycle is solved in the direction of increasing the size of the crack
  • Example 1-2 the stress in the direction of decreasing the pore size It can be judged to solve the problem.
  • Figure 6 shows the capacity retention rate according to the cycle progress of the coin-type half cell prepared in Example 1-2 and Comparative Example 2-2. Referring to FIG. 6, after 70 cycles, the capacity retention rate of 94.2% was shown in the case of the example, but the capacity retention rate of the comparative example was 70.2%.

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Abstract

The present invention relates to a binder solution for an anode having a hydrogen ion concentration of pH 2.5 to pH 4.5, an active material slurry for an anode comprising same, an anode using the active material slurry and an electrochemical device comprising the anode, wherein the binder solution for an anode includes: a thermal crosslinking polymer binder which is cross-linked by heat; and a solvent for dissolving the thermal crosslinking polymer binder. According to an example of the present invention, by alleviating the volumetric expansion of an anode active material due to the absorption and release of lithium which occur as an electrochemical device goes through its cycles, the durability of a layer of an anode active material is improved to thereby allow the lifespan characteristic of the electrochemical device to be improved, and the dispersibility of active material slurry for an anode remains outstanding to thereby allow the coating stability of the anode active material to be improved.

Description

애노드용 바인더 용액, 그를 포함하는 애노드용 활물질 슬러리, 그 활물질 슬러리를 이용한 애노드 및 이를 포함하는 전기화학소자An anode binder solution, an anode active material slurry comprising the same, an anode using the active material slurry and an electrochemical device comprising the same
본 발명은 애노드용 바인더 용액, 그를 포함하는 애노드용 활물질 슬러리, 그 활물질 슬러리를 이용한 애노드 및 이를 포함하는 전기화학소자에 관한 것으로서, 더욱 자세하게는 리튬의 흡장 및 방출에 따른 애노드 활물질의 부피팽창을 완화시킴으로써, 애노드의 내구성을 향상시켜 전기화학소자의 수명 특성을 향상시키는 애노드용 바인더 용액, 그를 포함하는 애노드용 활물질 슬러리, 그 활물질 슬러리를 이용한 애노드 및 이를 포함하는 전기화학소자에 관한 것이다.The present invention relates to an anode binder solution, an anode active material slurry comprising the same, an anode using the active material slurry, and an electrochemical device comprising the same, and more particularly, to reduce volume expansion of an anode active material due to occlusion and release of lithium. The present invention relates to an anode binder solution for improving durability of an anode to improve life characteristics of an electrochemical device, an anode active material slurry containing the same, an anode using the active material slurry, and an electrochemical device including the same.
본 출원은 2013년 6월 18일에 출원된 한국특허출원 제10-2013-0069920호에 기초한 우선권을 주장하며, 해당 출원의 명세서 및 도면에 개시된 모든 내용은 본 출원에 원용된다.This application claims priority based on Korean Patent Application No. 10-2013-0069920 filed on June 18, 2013, and all the contents disclosed in the specification and drawings of the application are incorporated in this application.
또한, 본 출원은 2014년 6월 18일에 출원된 한국특허출원 제10-2014-0074405호에 기초한 우선권을 주장하며, 해당 출원의 명세서 및 도면에 개시된 모든 내용은 본 출원에 원용된다.In addition, this application claims the priority based on Korean Patent Application No. 10-2014-0074405 filed on June 18, 2014, all the contents disclosed in the specification and drawings of the application is incorporated in this application.
최근 에너지 저장 기술에 대한 관심이 갈수록 높아지고 있다. 휴대폰, 캠코더 및 노트북 PC, 나아가서는 전기 자동차의 에너지까지 적용분야가 확대되면서 전기화학소자의 연구와 개발에 대한 노력이 점점 구체화되고 있다. 전기화학소자는 이러한 측면에서 가장 주목을 받고 있는 분야이고 그 중에서도 충방전이 가능한 이차전지의 개발은 관심의 초점이 되고 있으며, 최근에는 이러한 전지를 개발함에 있어서 용량 밀도 및 비에너지를 향상시키기 위하여 새로운 전극과 전지의 설계에 대한 연구개발로 진행되고 있다.Recently, interest in energy storage technology is increasing. As the field of application extends to the energy of mobile phones, camcorders, notebook PCs, and even electric vehicles, efforts for research and development of electrochemical devices are becoming more concrete. The electrochemical device is the area that is receiving the most attention in this respect, and the development of a secondary battery capable of charging and discharging has been the focus of attention, and in recent years in the development of such a battery in order to improve the capacity density and specific energy R & D on the design of electrodes and batteries is underway.
현재 적용되고 있는 이차전지 중에서 1990 년대 초에 개발된 리튬 이차전지는 수용액 전해액을 사용하는 Ni-MH, Ni-Cd, 황산-납 전지 등의 재래식 전지에 비해서 작동 전압이 높고 에너지 밀도가 월등히 크다는 장점으로 각광을 받고 있다.Among the secondary batteries currently applied, lithium secondary batteries developed in the early 1990s have a higher operating voltage and greater energy density than conventional batteries such as Ni-MH, Ni-Cd, and sulfuric acid-lead batteries that use an aqueous electrolyte solution. I am in the spotlight.
이러한 전기화학소자는 일반적으로 캐소드, 애노드, 및 상기 캐소드와 상기 애노드 사이에 개재된 세퍼레이터를 포함한다. 이때 상기 캐소드 및 상기 애노드는 각각의 집전체의 표면에, 전극 활물질, 고분자 바인더 및 상기 전극 활물질을 분산시키고, 상기 고분자 바인더를 용해시키는 용매를 포함하는 전극 활물질 슬러리를 도포하여 건조시킴으로써 전극 활물질층을 형성한다.Such electrochemical devices generally include a cathode, an anode, and a separator interposed between the cathode and the anode. At this time, the cathode and the anode is dispersed on the surface of each current collector, the electrode active material, the polymer binder and the electrode active material, and coated with an electrode active material slurry containing a solvent for dissolving the polymer binder to dry the electrode active material layer Form.
한편, 상기 전극 활물질 중에서도 애노드 활물질은 리튬의 흡장 및 방출에 따라 부피 팽창이 발생한다. 특히, 상기 애노드 활물질로서 규소 산화물계 활물질을 사용하는 경우 부피 팽창이 더욱 심화될 수 있다.Meanwhile, among the electrode active materials, the volume of the anode active material is increased by occluding and releasing lithium. In particular, when the silicon oxide-based active material is used as the anode active material, volume expansion may be further intensified.
전술한 바와 같이 상기 애노드 활물질의 부피 팽창으로 인해 전기화학소자의 사이클이 진행될수록, 애노드 활물질층의 표면에 형성되어 있던 기공의 크기가 커지면서, 크랙이 형성될 수 있으며, 이러한 크랙의 형성으로 인해 애노드 활물질층의 탈리가 발생할 수 있어, 전기화학소자의 충방전 특성을 저하시켜 결국엔 전기화학소자의 수명 특성을 저하시키는 문제가 있다.As described above, as the cycle of the electrochemical device proceeds due to the volume expansion of the anode active material, cracks may be formed while the pore size formed on the surface of the anode active material layer increases, and the formation of the cracks causes the anode. Desorption of the active material layer may occur, thereby lowering the charge / discharge characteristics of the electrochemical device, which in turn lowers the life characteristics of the electrochemical device.
따라서, 본 발명이 해결하고자 하는 과제는, 전기화학소자의 사이클 진행으로 인한 리튬의 흡장 및 방출에 따른 애노드 활물질의 부피팽창을 완화시킴으로써, 애노드 활물질층의 내구성을 향상시켜 전기화학소자의 수명 특성을 향상시키며, 나아가 애노드용 활물질 슬러리의 분산성을 우수하도록 유지시켜 애노드 활물질층의 코팅 안정성을 향상시키는 애노드용 바인더 용액, 그를 포함하는 애노드용 활물질 슬러리, 그 활물질 슬러리를 이용한 애노드 및 이를 포함하는 전기화학소자를 제공하는 것이다.Therefore, the problem to be solved by the present invention, by reducing the volume expansion of the anode active material due to the occlusion and release of lithium due to the progress of the cycle of the electrochemical device, improve the durability of the anode active material layer to improve the life characteristics of the electrochemical device Anode binder solution for improving the coating stability of the anode active material layer by further maintaining excellent dispersibility of the anode active material slurry, anode active material slurry comprising the same, anode using the active material slurry and electrochemical comprising the same It is to provide an element.
상기 과제를 해결하기 위하여, 본 발명의 일 측면에 따르면, 열에 의해 가교되는 열가교성 고분자 바인더; 및 상기 열가교성 고분자 바인더를 용해시키는 용매;를 포함하며, 수소이온농도가 pH 2.5 내지 pH 4.5, 바람직하게는 pH 3.0 내지 pH 3.5인 애노드용 바인더 용액이 제공된다.In order to solve the above problems, according to an aspect of the present invention, a thermal crosslinkable polymer binder crosslinked by heat; And a solvent for dissolving the thermally crosslinkable polymer binder. A binder solution for an anode having a hydrogen ion concentration of pH 2.5 to pH 4.5, preferably pH 3.0 to pH 3.5 is provided.
여기서, 상기 열가교성 고분자 바인더는, 작용기로서 카르복시기를 포함할 수 있다.Here, the thermal crosslinkable polymer binder may include a carboxy group as a functional group.
이때, 작용기로서 카르복시기를 포함하는 상기 열가교성 고분자 바인더는, 폴리아크릴산일 수 있다.In this case, the thermally crosslinkable polymer binder including a carboxyl group as a functional group may be polyacrylic acid.
그리고, 상기 용매는, 아세톤(acetone), 테트라 하이드로퓨란(tetra hydrofuran), 메틸렌 클로라이드(methylene chloride), 클로로포름(chloroform), 디메틸포름 아미드(dimethylform amide), N-메틸-2-피롤리돈(N-methyl-2-pyrrolidone, NMP), 시클로헥산(cyclohexane) 및 물로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물일 수 있다.The solvent may be acetone, tetra hydrofuran, methylene chloride, chloroform, dimethylform amide, N-methyl-2-pyrrolidone (N). -methyl-2-pyrrolidone, NMP), cyclohexane and any one selected from the group consisting of water or a mixture of two or more thereof.
그리고, 상기 애노드용 바인더 용액은, 수계 바인더를 더 포함하는 것일 수 있다.In addition, the anode binder solution may further include an aqueous binder.
이때, 상기 열가교성 고분자 바인더와 상기 수계 바인더의 중량비가 2:8 내지 5:5, 바람직하게는 2:8 내지 4:6일 수 있다.In this case, the weight ratio of the thermally crosslinkable polymer binder and the aqueous binder may be 2: 8 to 5: 5, preferably 2: 8 to 4: 6.
그리고, 상기 수계 바인더는, 스타이렌 부타디엔 고무, 카르복시메틸셀룰로오스, 폴리테트라풀루오로에틸렌, 폴리에틸렌, 폴리프로필렌, 에틸렌프로필렌공중합체, 폴리부타디엔, 부틸고무, 불소고무, 폴리에틸렌옥사이드, 폴리비닐피롤리돈, 폴리에피클로로히드린, 폴리포스파겐, 폴리아크릴로니트릴, 폴리스타이렌, 에틸렌프로필렌디엔공중합체, 폴리비닐피리딘, 클로로설폰화폴리에틸렌, 라텍스, 폴리에스테르수지, 아크릴수지, 페놀수지, 에폭시수지, 폴리비닐알콜 및 히드록시프로필셀룰로오스로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물일 수 있다.The aqueous binder may include styrene butadiene rubber, carboxymethyl cellulose, polytetrafluoroethylene, polyethylene, polypropylene, ethylene propylene copolymer, polybutadiene, butyl rubber, fluorine rubber, polyethylene oxide, polyvinylpyrrolidone , Polyepichlorohydrin, polyphosphagen, polyacrylonitrile, polystyrene, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenolic resin, epoxy resin, polyvinyl It may be any one selected from the group consisting of alcohol and hydroxypropyl cellulose or a mixture of two or more thereof.
한편, 본 발명의 다른 측면에 따르면, 애노드용 바인더 용액; 및 상기 애노드용 바인더 용액에 분산되는 애노드 활물질;을 포함하되, 상기 애노드용 바인더 용액은, 전술한 본 발명의 애노드용 바인더 용액인 것을 특징으로 하는 애노드용 활물질 슬러리가 제공된다.On the other hand, according to another aspect of the invention, the binder solution for the anode; And an anode active material dispersed in the anode binder solution, wherein the anode binder solution is provided with an anode active material slurry, wherein the anode binder solution of the present invention is described above.
이때, 상기 애노드용 활물질 슬러리의 수소이온농도는 pH 2.5 내지 pH 4.5, 바람직하게는 pH 3.0 내지 pH 3.5 일 수 있다.At this time, the hydrogen ion concentration of the anode active material slurry may be pH 2.5 to pH 4.5, preferably pH 3.0 to pH 3.5.
그리고, 상기 애노드용 활물질 슬러리의 고형분량은 상기 애노드용 활물질 슬러리 중 43 내지 50 중량%일 수 있다.In addition, the solid content of the anode active material slurry may be 43 to 50% by weight of the active material slurry for the anode.
그리고, 상기 애노드 활물질은, 리튬 금속, 탄소재, 금속 화합물, 금속 산화물 또는 이들의 혼합물을 포함하는 것일 수 있다.The anode active material may include lithium metal, a carbon material, a metal compound, a metal oxide, or a mixture thereof.
여기서, 상기 금속 화합물은, Si, Ge, Sn, Pb, P, Sb, Bi, Al, Ga, In, Ti, Mn, Fe, Co, Ni, Cu, Zn, Ag, Mg, Sr, 및 Ba로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물일 수 있다.Here, the metal compound is Si, Ge, Sn, Pb, P, Sb, Bi, Al, Ga, In, Ti, Mn, Fe, Co, Ni, Cu, Zn, Ag, Mg, Sr, and Ba It may be any one selected from the group consisting of or a mixture of two or more thereof.
그리고, 상기 금속 산화물은, 규소 산화물, 주석 산화물, 티탄 산화물 및 리튬 바나듐계 산화물로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물일 수 있다.The metal oxide may be any one selected from the group consisting of silicon oxide, tin oxide, titanium oxide, and lithium vanadium oxide, or a mixture of two or more thereof.
한편, 본 발명의 다른 측면에 따르면, 집전체; 및 상기 집전체의 일면 또는 양면 상에 형성되어 있으며, 전술한 본 발명의 애노드용 활물질 슬러리의 건조단계 결과물로 이루어진 애노드 활물질층;을 포함하는 애노드가 제공된다.On the other hand, according to another aspect of the invention, the current collector; And an anode active material layer formed on one surface or both surfaces of the current collector, and formed of a result of the drying step of the active material slurry for the anode of the present invention described above.
여기서, 상기 건조단계에 의해, 상기 용매가 제거되고, 상기 열가교성 고분자 바인더가 서로 가교되어 가교 고분자 네트워크를 형성할 수 있다.Here, by the drying step, the solvent is removed, the thermal crosslinkable polymer binder can be crosslinked with each other to form a crosslinked polymer network.
이때, 상기 건조단계는, 120 내지 140 ℃의 온도에서 1차 건조를 통해 상기 용매를 제거하고, 진공상태의 140 내지 160 ℃의 온도에서 2차 건조를 통해 상기 가교 고분자 네트워크를 형성하는 것일 수 있다.At this time, the drying step, to remove the solvent through the first drying at a temperature of 120 to 140 ℃, may be to form the cross-linked polymer network through the secondary drying at a temperature of 140 to 160 ℃ in a vacuum state. .
그리고, 본 발명의 또 다른 측면에 따르면, 집전체; 및 상기 집전체의 일면 또는 양면 상에 형성되어 있는 애노드 활물질층;을 포함하는 애노드로서, 상기 애노드 활물질층은, 애노드 활물질 및 고분자 바인더를 포함하고, 상기 고분자 바인더는, 열에 의해 가교되는 열가교성 고분자 바인더 및 수계 바인더의 혼합물이며, 상기 열가교성 고분자 바인더와 상기 수계 바인더의 중량비가 2:8 내지 5:5이고, 상기 열가교성 고분자는 서로 가교되어 가교 고분자 네트워크를 형성하는 것을 특징으로 하는 애노드가 제공된다.And, according to another aspect of the invention, the current collector; And an anode active material layer formed on one or both surfaces of the current collector, wherein the anode active material layer comprises an anode active material and a polymer binder, and the polymer binder is a heat crosslinkable polymer that is crosslinked by heat. A mixture of a binder and an aqueous binder, wherein the weight ratio of the thermally crosslinkable polymer binder and the aqueous binder is 2: 8 to 5: 5, and the thermally crosslinkable polymer is crosslinked with each other to form a crosslinked polymer network. do.
이때, 상기 열가교성 고분자 바인더는, 폴리아크릴산이고, 상기 수계 바인더는, 스타이렌 부타디엔 고무일 수 있다.In this case, the thermally crosslinkable polymer binder may be polyacrylic acid, and the aqueous binder may be styrene butadiene rubber.
한편, 본 발명의 또 다른 측면에 따르면, 캐소드, 애노드, 상기 캐소드와 상기 애노드 사이에 개재된 세퍼레이터 및 비수 전해액을 포함하는 전기화학소자에 있어서, 상기 애노드는, 전술한 본 발명의 애노드인 전기화학소자가 제공된다.On the other hand, according to another aspect of the present invention, in the electrochemical device comprising a cathode, an anode, a separator interposed between the cathode and the anode and the non-aqueous electrolyte, the anode is the electrochemical of the above-described anode of the present invention An element is provided.
여기서, 상기 전기화학소자는, 리튬 이차전지일 수 있다.Here, the electrochemical device may be a lithium secondary battery.
본 발명의 일 실시예에 따르면, 전기화학소자의 사이클 진행으로 인한 리튬의 흡장 및 방출에 따른 애노드 활물질의 부피팽창을 완화시킴으로써, 애노드 활물질층의 내구성을 향상시켜 전기화학소자의 수명 특성을 향상시킬 수 있다.According to an embodiment of the present invention, by reducing the volume expansion of the anode active material due to the occlusion and release of lithium due to the progress of the cycle of the electrochemical device, to improve the durability characteristics of the anode active material layer to improve the life characteristics of the electrochemical device Can be.
그리고, 애노드용 활물질 슬러리의 분산성을 우수하도록 유지시켜 애노드 활물질층의 코팅 안정성을 향상시킬 수 있다.In addition, the coating stability of the anode active material layer may be improved by maintaining the dispersibility of the active material slurry for the anode.
본 명세서에 첨부되는 다음의 도면은 본 발명의 바람직한 실시예를 예시하는 것이며, 전술한 발명의 내용과 함께 본 발명의 기술사상을 더욱 이해시키는 역할을 하는 것이므로, 본 발명은 그러한 도면에 기재된 사항에만 한정되어 해석되어서는 아니 된다.The following drawings, which are attached to this specification, illustrate exemplary embodiments of the present invention, and together with the contents of the present invention serve to further understand the technical spirit of the present invention, the present invention is limited to the matters described in such drawings. It should not be construed as limited.
도 1은 본 발명의 실시예 및 비교예에 따른 애노드용 활물질 슬러리의 점탄성을 나타낸 그래프이다.1 is a graph showing viscoelastic properties of an active material slurry for anode according to Examples and Comparative Examples of the present invention.
도 2는 본 발명의 일 실시예에 따라 제조된 애노드의 표면을 나타낸 SEM 사진이다.Figure 2 is a SEM photograph showing the surface of the anode prepared according to an embodiment of the present invention.
도 3은 본 발명의 일 실시예에 따라 제조된 애노드로서, 70 사이클 후의 표면을 나타낸 SEM 사진이다.Figure 3 is an anode prepared according to an embodiment of the present invention, a SEM photograph showing the surface after 70 cycles.
도 4는 본 발명의 일 비교예에 따라 제조된 애노드의 표면을 나타낸 SEM 사진이다.Figure 4 is a SEM photograph showing the surface of the anode prepared according to a comparative example of the present invention.
도 5는 본 발명의 일 비교예에 따라 제조된 애노드로서, 70 사이클 후의 표면을 나타낸 SEM 사진이다.5 is an anode prepared according to a comparative example of the present invention, a SEM photograph showing the surface after 70 cycles.
도 6은 본 발명의 일 실시예 및 일 비교예에 따라 제조된 코인형 반쪽 셀의 70 사이클 동안의 용량 유지율을 비교하여 나타낸 그래프이다.6 is a graph comparing capacity retention rates for 70 cycles of coin-shaped half cells prepared according to one embodiment and one comparative example of the present invention.
이하, 본 발명을 상세히 설명하기로 한다. 본 명세서 및 청구범위에 사용된 용어나 단어는 통상적이거나 사전적인 의미로 한정해서 해석되어서는 아니 되며, 발명자는 그 자신의 발명을 가장 최선의 방법으로 설명하기 위해 용어의 개념을 적절하게 정의할 수 있다는 원칙에 입각하여 본 발명의 기술적 사상에 부합하는 의미와 개념으로 해석되어야만 한다.Hereinafter, the present invention will be described in detail. The terms or words used in this specification and claims are not to be construed as limiting in their usual or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best explain their invention in the best way possible. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.
본 발명에 따른 애노드용 바인더 용액은, 열에 의해 가교되는 열가교성 고분자 바인더; 및 상기 열가교성 고분자 바인더를 용해시키는 용매;를 포함하며, 수소이온농도가 pH 2.5 내지 pH 4.5, 바람직하게는 pH 3.0 내지 pH 3.5 이다.The binder solution for the anode according to the present invention comprises a thermal crosslinkable polymer binder crosslinked by heat; And a solvent for dissolving the thermally crosslinkable polymer binder, wherein the hydrogen ion concentration is pH 2.5 to pH 4.5, preferably pH 3.0 to pH 3.5.
그리고, 본 발명에 따른 애노드용 활물질 슬러리는, 애노드용 바인더 용액; 및 상기 애노드용 바인더 용액에 분산되는 애노드 활물질;을 포함하되, 상기 애노드용 바인더 용액은, 전술한 본 발명에 따른 애노드용 바인더 용액인 것을 특징으로 한다. 이때, 상기 애노드용 활물질 슬러리의 수소이온농도는 pH 2.5 내지 pH 4.5, 바람직하게는 pH 3.0 내지 pH 3.5일 수 있다.In addition, the anode active material slurry according to the present invention is an anode binder solution; And an anode active material dispersed in the anode binder solution; wherein the anode binder solution is an anode binder solution according to the present invention. At this time, the hydrogen ion concentration of the anode active material slurry may be pH 2.5 to pH 4.5, preferably pH 3.0 to pH 3.5.
전기화학소자의 애노드에 적용되어 사용되는 애노드 활물질은 리튬의 흡장 및 방출에 따라 부피 팽창이 발생한다. 특히, 상기 애노드 활물질로서 규소 산화물계 활물질을 사용하는 경우 부피 팽창이 더욱 심화될 수 있다. 이러한 부피 팽창으로 인해 전기화학소자의 사이클이 진행될수록, 애노드 활물질층의 표면에 형성되어 있던 기공의 크기가 커지면서, 크랙이 형성될 수 있으며, 이러한 크랙의 형성으로 인해 애노드 활물질층의 탈리가 발생하여, 활물질과 집전체간의 도전성이 저하될 뿐만 아니라 애노드 활물질간의 도전성이 저하됨으로써, 전기화학소자의 충방전 특성을 저하시켜 결국엔 전기화학소자의 수명 특성을 저하시키게 된다.The anode active material used to be applied to the anode of the electrochemical device generates volume expansion upon occlusion and release of lithium. In particular, when the silicon oxide-based active material is used as the anode active material, volume expansion may be further intensified. As the cycle of the electrochemical device proceeds due to such volume expansion, cracks may be formed while the pore size formed on the surface of the anode active material layer increases, and the formation of such cracks causes desorption of the anode active material layer. In addition, the conductivity between the active material and the current collector is lowered, and the conductivity between the anode active material is lowered, thereby lowering the charge / discharge characteristics of the electrochemical device, which in turn lowers the life characteristics of the electrochemical device.
이러한 문제점을 해결하기 위해서 본 발명에서는, 애노드 제조시 사용되는 고분자 바인더로서, 열에 의해 가교되는 열가교성 고분자 바인더를 사용한다.In order to solve this problem, in the present invention, a heat crosslinkable polymer binder crosslinked by heat is used as the polymer binder used in the production of the anode.
상기 열가교성 고분자 바인더를 포함하는 애노드용 활물질 슬러리를 집전체의 적어도 일면에 도포한 후 건조시키게 되면, 상기 열가교성 고분자 바인더는 서로 가교되어 가교 고분자 네트워크를 형성하게 되고, 상기 가교 고분자 네트워크는 활물질층의 내구성을 향상시켜 전기화학소자의 충방전에 따른 애노드 활물질의 부피 팽창을 완화시키게 된다.When the anode active material slurry including the thermally crosslinkable polymer binder is applied to at least one surface of a current collector and then dried, the thermally crosslinkable polymer binder is crosslinked with each other to form a crosslinked polymer network, and the crosslinked polymer network is an active material layer. By improving the durability of the volume of the anode active material due to the charge and discharge of the electrochemical device is alleviated.
그리고, 상기 애노드용 바인더 용액 및 상기 애노드용 활물질 슬러리의 수소이온농도가 상기 수치범위를 만족하게 되면, 탄성에 비해 점성이 매우 높은 액상 거동을 발현하게 됨으로써 상기 바인더 용액 및 상기 활물질 슬러리의 분산성을 우수하도록 유지시켜 애노드 활물질층의 코팅 안정성을 향상시키게 된다.When the hydrogen ion concentration of the anode binder solution and the anode active material slurry satisfies the numerical range, the binder solution and the active material slurry dispersibility may be expressed by expressing a liquid behavior having a very high viscosity compared to elasticity. Maintained to be excellent to improve the coating stability of the anode active material layer.
이때, 상기 애노드용 활물질 슬러리의 고형분량은 상기 애노드용 활물질 슬러리 중 43 내지 50 중량%일 수 있다. 상기 수치범위를 만족하게 되면, 상기 애노드용 활물질 슬러리의 적절한 점도가 유지되어 집전체 상에 균일하게 코팅시킬 수 있으며, 건조시켜야 할 수분의 양이 과하지 않아 건조시간을 적절하게 유지할 수 있어 경제적이다.In this case, the solid amount of the active material slurry for the anode may be 43 to 50% by weight of the active material slurry for the anode. When the numerical range is satisfied, an appropriate viscosity of the active material slurry for the anode may be maintained and uniformly coated on the current collector, and the amount of moisture to be dried is not excessive so that the drying time can be properly maintained.
한편, 상기 열가교성 고분자 바인더는, 작용기로서 카르복시기를 포함하는 것일 수 있다. 상기 카르복시기는 열에 의하여 가교되므로 분자간의 수소 결합 이외의 무수 카르복시기 그룹(carboxylic anhydride group)을 형성하여, 선형의 고분자 사슬이 부분적으로 가교 고분자 네트워크로 변화하여 애노드 활물질의 부피팽창을 완화시킬 수 있게 된다.On the other hand, the thermally crosslinkable polymer binder may be one containing a carboxyl group as a functional group. Since the carboxyl group is crosslinked by heat, it forms anhydrous carboxylic anhydride groups other than hydrogen bonds between molecules, so that the linear polymer chain may be partially changed into a crosslinked polymer network to mitigate volume expansion of the anode active material.
이때, 작용기로서 카르복시기를 포함하는 상기 열가교성 고분자 바인더는, 폴리아크릴산일 수 있다.In this case, the thermally crosslinkable polymer binder including a carboxyl group as a functional group may be polyacrylic acid.
이때, 상기 폴리아크릴산의 중량평균분자량은, 400,000 내지 800,000일 수 있으나 이에만 한정되는 것은 아니다.In this case, the weight average molecular weight of the polyacrylic acid may be 400,000 to 800,000, but is not limited thereto.
한편, 상기 애노드용 바인더 용액은, 수계 바인더를 더 포함할 수 있다.Meanwhile, the anode binder solution may further include an aqueous binder.
이때, 상기 열가교성 고분자 바인더와 상기 수계 바인더의 중량비는 2:8 내지 5:5, 바람직하게는 2:8 내지 4:6일 수 있다. 여기서, 상기 수계 바인더의 중량비가 상기 수치범위의 상한치를 초과하게 되면, 전극 활물질층의 기계적 물성은 향상될 수 있지만, 전극 활물질층의 저항을 증가시킬 우려가 있다. 그리고, 상기 열가교성 고분자 바인더의 중량비가 상기 수치범위의 상한치를 초과하게 되면, 전극 활물질층의 기계적 물성이 저하되고, 전극 활물질 슬러리의 안정성이 저하될 수 있다. 따라서, 상기 중량비를 만족하게 되면, 적절한 양의 가교 고분자 네트워크가 형성되며, 이로써, 애노드 활물질층의 부피팽창을 완화시킬 수 있다.In this case, the weight ratio of the thermal crosslinkable polymer binder and the aqueous binder may be 2: 8 to 5: 5, preferably 2: 8 to 4: 6. Here, when the weight ratio of the aqueous binder exceeds the upper limit of the numerical range, the mechanical properties of the electrode active material layer may be improved, but there is a concern that the resistance of the electrode active material layer may be increased. When the weight ratio of the thermally crosslinkable polymer binder exceeds the upper limit of the numerical range, the mechanical properties of the electrode active material layer may decrease, and the stability of the electrode active material slurry may decrease. Therefore, when the weight ratio is satisfied, an appropriate amount of the crosslinked polymer network is formed, thereby alleviating the volume expansion of the anode active material layer.
여기서, 상기 수계 바인더는, 수용성 또는 수분산성의 바인더 고분자를 의미하는 것으로, 스타이렌 부타디엔 고무, 카르복시메틸셀룰로오스, 폴리테트라풀루오로에틸렌, 폴리에틸렌, 폴리프로필렌, 에틸렌프로필렌공중합체, 폴리부타디엔, 부틸고무, 불소고무, 폴리에틸렌옥사이드, 폴리비닐피롤리돈, 폴리에피클로로히드린, 폴리포스파겐, 폴리아크릴로니트릴, 폴리스타이렌, 에틸렌프로필렌디엔공중합체, 폴리비닐피리딘, 클로로설폰화폴리에틸렌, 라텍스, 폴리에스테르수지, 아크릴수지, 페놀수지, 에폭시수지, 폴리비닐알콜 및 히드록시프로필셀룰로오스로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물일 수 있다.Here, the water-based binder refers to a water-soluble or water-dispersible binder polymer, styrene butadiene rubber, carboxymethyl cellulose, polytetrafluoroethylene, polyethylene, polypropylene, ethylene propylene copolymer, polybutadiene, butyl rubber , Fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphagen, polyacrylonitrile, polystyrene, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin , Acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol and hydroxypropyl cellulose may be any one selected from the group consisting of or a mixture of two or more thereof.
한편, 상기 애노드 활물질의 비제한적인 예로는 종래 전기화학소자의 애노드에 사용될 수 있는 통상적인 애노드 활물질이 사용 가능하며, 특히 리튬 금속, 탄소재, 금속 화합물, 금속 산화물 또는 이들의 혼합물을 포함할 수 있다.On the other hand, non-limiting examples of the anode active material may be a conventional anode active material that can be used in the anode of the conventional electrochemical device, in particular may include lithium metal, carbon material, metal compounds, metal oxides or mixtures thereof. have.
이때, 상기 탄소재로는, 탄소, 석유코크(petroleum coke), 활성화 탄소(activated carbon), 그래파이트(graphite) 또는 기타 탄소류 등과 같은 리튬 흡착물질 등이 사용될 수 있다.In this case, as the carbon material, a lithium adsorption material such as carbon, petroleum coke, activated carbon, graphite, or other carbons may be used.
그리고, 상기 금속 화합물은, Si, Ge, Sn, Pb, P, Sb, Bi, Al, Ga, In, Ti, Mn, Fe, Co, Ni, Cu, Zn, Ag, Mg, Sr, 및 Ba로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물일 수 있다.The metal compound may be Si, Ge, Sn, Pb, P, Sb, Bi, Al, Ga, In, Ti, Mn, Fe, Co, Ni, Cu, Zn, Ag, Mg, Sr, and Ba. It may be any one selected from the group consisting of or a mixture of two or more thereof.
그리고, 상기 금속 산화물은, 규소 산화물, 주석 산화물, 티탄 산화물 및 리튬 바나듐계 산화물로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물일 수 있다.The metal oxide may be any one selected from the group consisting of silicon oxide, tin oxide, titanium oxide, and lithium vanadium oxide, or a mixture of two or more thereof.
그리고, 상기 용매는, 아세톤(acetone), 테트라 하이드로퓨란(tetra hydrofuran), 메틸렌 클로라이드(methylene chloride), 클로로포름(chloroform), 디메틸포름 아미드(dimethylform amide), N-메틸-2-피롤리돈(N-methyl-2-pyrrolidone, NMP), 시클로헥산(cyclohexane), 및 물로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물일 수 있으나, 이에만 한정하는 것은 아니다.The solvent may be acetone, tetra hydrofuran, methylene chloride, chloroform, dimethylform amide, N-methyl-2-pyrrolidone (N). -methyl-2-pyrrolidone, NMP), cyclohexane, and any one selected from the group consisting of water or a mixture of two or more thereof, but is not limited thereto.
다만, 상기 용매는, 그 종류에 따라 최종적으로 제조된 전기화학소자 내에 잔존할 경우, 다양한 부반응을 초래할 수도 있으므로, 전기화학소자의 제조과정에서 제거될 수 있다.However, the solvent may be removed in the manufacturing process of the electrochemical device, since the solvent may cause various side reactions when remaining in the finally manufactured electrochemical device.
한편, 본 발명의 일 측면에 따르면, 집전체; 및 상기 집전체의 일면 또는 양면 상에 형성되어 있으며, 전술한 본 발명의 애노드용 활물질 슬러리의 건조단계 결과물로 이루어진 애노드 활물질층;을 포함하는 애노드가 제공된다.On the other hand, according to an aspect of the present invention, the current collector; And an anode active material layer formed on one surface or both surfaces of the current collector, and formed of a result of the drying step of the active material slurry for the anode of the present invention described above.
여기서, 상기 집전체의 비제한적인 예로는 구리, 금, 니켈 또는 구리 합금 또는 이들의 조합에 의하여 제조되는 호일 등이 있다.Here, non-limiting examples of the current collector include a foil made by copper, gold, nickel or a copper alloy or a combination thereof.
그리고, 상기 건조단계에 의해, 상기 용매가 제거되고, 상기 열가교성 고분자 바인더가 서로 가교되어 가교 고분자 네트워크를 형성할 수 있으며, 이때, 상기 건조단계는, 120 내지 140 ℃의 온도에서 1차 건조를 통해 상기 용매를 제거하고, 진공상태의 140 내지 160 ℃의 온도에서 2차 건조를 통해 상기 가교 고분자 네트워크를 형성할 수 있다.And, by the drying step, the solvent is removed, the thermal crosslinkable polymer binder can be cross-linked with each other to form a crosslinked polymer network, wherein the drying step, the first drying at a temperature of 120 to 140 ℃ The solvent may be removed, and the crosslinked polymer network may be formed through secondary drying at a temperature of 140 to 160 ° C. in a vacuum state.
그리고, 본 발명의 또 다른 측면에 따르면, 집전체; 및 상기 집전체의 일면 또는 양면 상에 형성되어 있는 애노드 활물질층;을 포함하는 애노드로서, 상기 애노드 활물질층은, 애노드 활물질 및 고분자 바인더를 포함하고, 상기 고분자 바인더는, 열에 의해 가교되는 열가교성 고분자 바인더 및 수계 바인더의 혼합물이며, 상기 열가교성 고분자 바인더와 상기 수계 바인더의 중량비가 2:8 내지 5:5이고, 상기 열가교성 고분자는 서로 가교되어 가교 고분자 네트워크를 형성하는 것을 특징으로 하는 애노드가 제공된다.And, according to another aspect of the invention, the current collector; And an anode active material layer formed on one or both surfaces of the current collector, wherein the anode active material layer comprises an anode active material and a polymer binder, and the polymer binder is a heat crosslinkable polymer that is crosslinked by heat. A mixture of a binder and an aqueous binder, wherein the weight ratio of the thermally crosslinkable polymer binder and the aqueous binder is 2: 8 to 5: 5, and the thermally crosslinkable polymer is crosslinked with each other to form a crosslinked polymer network. do.
여기서, 상기 열가교성 고분자 바인더와 상기 수계 바인더의 중량비와 관련하여, 상기 수계 바인더의 중량비가 상기 수치범위의 상한치를 초과하게 되면, 전극 활물질층의 기계적 물성은 향상될 수 있지만, 전극 활물질층의 저항을 증가시킬 우려가 있다. 그리고, 상기 열가교성 고분자 바인더의 중량비가 상기 수치범위의 상한치를 초과하게 되면, 전극 활물질층의 기계적 물성이 저하되고, 전극 활물질 슬러리의 안정성이 저하될 수 있다. 따라서, 상기 중량비를 만족하게 되면, 적절한 양의 가교 고분자 네트워크가 형성되며, 이로써, 애노드 활물질층의 부피팽창을 완화시킬 수 있다.Here, with respect to the weight ratio of the thermally crosslinkable polymer binder and the aqueous binder, if the weight ratio of the aqueous binder exceeds the upper limit of the numerical range, the mechanical properties of the electrode active material layer can be improved, but the resistance of the electrode active material layer There is a fear of increasing. When the weight ratio of the thermally crosslinkable polymer binder exceeds the upper limit of the numerical range, the mechanical properties of the electrode active material layer may decrease, and the stability of the electrode active material slurry may decrease. Therefore, when the weight ratio is satisfied, an appropriate amount of the crosslinked polymer network is formed, thereby alleviating the volume expansion of the anode active material layer.
이때, 상기 열가교성 고분자 바인더는, 폴리아크릴산이고, 상기 수계 바인더는, 스타이렌 부타디엔 고무일 수 있다.In this case, the thermally crosslinkable polymer binder may be polyacrylic acid, and the aqueous binder may be styrene butadiene rubber.
한편, 본 발명의 또 다른 측면에 따르면, 캐소드, 애노드, 상기 캐소드와 상기 애노드 사이에 개재된 세퍼레이터 및 비수 전해액을 포함하는 전기화학소자에 있어서, 상기 애노드는, 전술한 본 발명의 애노드인 것을 특징으로 하는 전기화학소자가 제공된다.On the other hand, according to another aspect of the present invention, in the electrochemical device comprising a cathode, an anode, a separator interposed between the cathode and the anode and the non-aqueous electrolyte, the anode is characterized in that the anode of the present invention described above An electrochemical device is provided.
이때, 본 발명의 전기화학소자는 전기 화학 반응을 하는 모든 소자를 포함하며, 구체적인 예를 들면, 모든 종류의 1차, 이차전지, 연료전지, 태양전지 또는 슈퍼 커패시터 소자와 같은 커패시터(capacitor) 등이 있다. 특히, 상기 이차전지 중 리튬 금속 이차전지, 리튬이온 이차전지, 리튬 폴리머 이차전지 또는 리튬 이온 폴리머 이차전지 등을 포함하는 리튬 이차전지가 바람직하다.In this case, the electrochemical device of the present invention includes all devices that perform an electrochemical reaction, and specific examples include capacitors such as all kinds of primary, secondary, fuel, solar, or supercapacitor devices. There is this. In particular, a lithium secondary battery including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery or a lithium ion polymer secondary battery among the secondary batteries is preferable.
그리고, 본 발명에 따른 전기화학소자는, 일반적인 공정인 권취(winding) 이외에도 세퍼레이터와 전극의 스택(stack, lamination), 폴딩(folding) 및 스택/폴딩 공정이 가능하다.In addition to the general winding process, the electrochemical device according to the present invention may perform stacking, lamination, folding, and stacking / folding processes of the separator and the electrode.
그리고, 전기화학소자의 외형은 특별한 제한이 없으나, 캔을 사용한 원통형, 각형, 파우치(pouch)형 또는 코인(coin)형 등이 될 수 있다.The external shape of the electrochemical device is not particularly limited, but may be cylindrical, square, pouch or coin type using a can.
한편, 본 발명 따른 전기화학소자에 적용될 캐소드로는 특별히 제한되지 않으며, 당업계에 알려진 통상적인 방법에 따라 캐소드 활물질을 집전체에 결착된 형태로 제조할 수 있다.Meanwhile, the cathode to be applied to the electrochemical device according to the present invention is not particularly limited, and the cathode active material may be manufactured in a form bound to the current collector according to conventional methods known in the art.
상기 캐소드 활물질의 비제한적인 예로는 종래 전기화학소자의 캐소드에 사용될 수 있는 통상적인 캐소드 활물질이 사용 가능하며, 특히 리튬망간 산화물, 리튬코발트 산화물, 리튬니켈 산화물, 리튬철 산화물 또는 이들을 조합한 리튬복합 산화물을 사용할 수 있다. 그리고 캐소드 집전체의 비제한적인 예로는 알루미늄, 니켈 또는 이들의 조합에 의하여 제조되는 호일 등이 있다.Non-limiting examples of the cathode active material may be a conventional cathode active material that can be used for the cathode of the conventional electrochemical device, in particular lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron oxide or a combination of these lithium composites Oxides can be used. And non-limiting examples of the cathode current collector is a foil produced by aluminum, nickel or a combination thereof.
한편, 본 발명에서 사용되는 세퍼레이터는 당해 분야에서 통상적으로 사용되는 다공성 기재라면 모두 사용이 가능하고, 예를 들면 폴리올레핀계 다공성 막(membrane) 또는 부직포를 사용할 수 있으나, 이에 특별히 한정되는 것은 아니다.On the other hand, the separator used in the present invention can be used as long as it is a porous substrate commonly used in the art, for example, a polyolefin-based porous membrane (membrane) or non-woven fabric may be used, but is not particularly limited thereto.
상기 폴리올레핀계 다공성 막의 예로는, 고밀도 폴리에틸렌, 선형 저밀도 폴리에틸렌, 저밀도 폴리에틸렌, 초고분자량 폴리에틸렌과 같은 폴리에틸렌, 폴리프로필렌, 폴리부틸렌, 폴리펜텐 등의 폴리올레핀계 고분자를 각각 단독으로 또는 이들을 혼합한 고분자로 형성한 막(membrane)을 들 수 있다.Examples of the polyolefin-based porous membrane, polyolefin-based polymers such as polyethylene, polypropylene, polybutylene, polypentene, such as high density polyethylene, linear low density polyethylene, low density polyethylene, ultra high molecular weight polyethylene, respectively, or a mixture thereof One membrane may be mentioned.
상기 부직포로는 폴리올레핀계 부직포 외에 예를 들어, 폴리에틸렌테레프탈레이트 (polyethyleneterephthalate), 폴리부틸렌테레프탈레이트 (polybutyleneterephthalate), 폴리에스테르 (polyester), 폴리아세탈 (polyacetal), 폴리아미드 (polyamide), 폴리카보네이트 (polycarbonate), 폴리이미드 (polyimide), 폴리에테르에테르케톤 (polyetheretherketone), 폴리에테르설폰 (polyethersulfone), 폴리페닐렌옥사이드 (polyphenyleneoxide), 폴리페닐렌설파이드 (polyphenylenesulfide), 폴리에틸렌나프탈렌 (polyethylenenaphthalene) 등을 각각 단독으로 또는 이들을 혼합한 고분자로 형성한 부직포를 들 수 있다. 부직포의 구조는 장섬유로 구성된 스폰본드 부직포 또는 멜트 블로운 부직포일 수 있다.The nonwoven fabric may be, for example, polyethylene terephthalate, polybutyleneterephthalate, polyester, polyacetal, polyamide, polycarbonate, or polycarbonate. ), Polyimide, polyetheretherketone, polyethersulfone, polyphenyleneoxide, polyphenylenesulfide, polyethylenenaphthalene, etc., alone or separately The nonwoven fabric formed from the polymer which mixed these is mentioned. The structure of the nonwoven can be a spunbond nonwoven or melt blown nonwoven composed of long fibers.
상기 다공성 기재의 두께는 특별히 제한되지 않으나, 5 ㎛ 내지 50 ㎛일 수 있고, 다공성 기재에 존재하는 기공 크기 및 기공도 역시 특별히 제한되지 않으나 각각 0.01 ㎛ 내지 50 ㎛ 및 10 내지 95 %일 수 있다.The thickness of the porous substrate is not particularly limited, but may be 5 μm to 50 μm, and the pore size and pore present in the porous substrate are also not particularly limited, but may be 0.01 μm to 50 μm and 10 to 95%, respectively.
또한, 상기 세퍼레이터의 기계적 강도 향상 및 전기화학소자의 안전성을 향상시키기 위해, 상기 다공성 기재의 적어도 일면에, 무기물 입자와 고분자 바인더를 포함하는 다공성 코팅층을 더 포함할 수 있다.In addition, in order to improve the mechanical strength of the separator and improve the safety of the electrochemical device, at least one surface of the porous substrate may further include a porous coating layer including inorganic particles and a polymer binder.
여기서, 상기 무기물 입자는, 전기화학적으로 안정하기만 하면 특별히 제한되지 않는다. 즉, 본 발명에서 사용할 수 있는 무기물 입자는 적용되는 전기화학소자의 작동 전압 범위(예컨대, Li/Li+ 기준으로 0 내지 5 V)에서 산화 및/또는 환원 반응이 일어나지 않는 것이면 특별히 제한되지 않는다. 특히, 무기물 입자로서 유전율이 높은 무기물 입자를 사용하는 경우, 액체 전해질 내 전해질 염, 예컨대 리튬염의 해리도 증가에 기여하여 전해액의 이온 전도도를 향상시킬 수 있다.Herein, the inorganic particles are not particularly limited as long as they are electrochemically stable. That is, the inorganic particles that can be used in the present invention are not particularly limited as long as the oxidation and / or reduction reactions do not occur in the operating voltage range (for example, 0 to 5 V on the basis of Li / Li + ) of the applied electrochemical device. In particular, when inorganic particles having a high dielectric constant are used as the inorganic particles, the ionic conductivity of the electrolyte may be improved by contributing to an increase in the dissociation degree of the electrolyte salt, such as lithium salt, in the liquid electrolyte.
그리고, 상기 고분자 바인더는, 폴리비닐리덴 풀루오라이드-헥사풀루오로프로필렌 (polyvinylidene fluoride-co-hexafluoropropylene, PVDF-HFP), 폴리비닐리덴 풀루오라이드-클로로트리풀루오로에틸렌 (polyvinylidene fluoride-co-chlorotrifluoroethylene), 폴리비닐리덴 풀루오라이드-트리클로로에틸렌 (polyvinylidene fluoride-co-trichloroethylene), 폴리메틸메타크릴레이트 (polymethylmethacrylate), 폴리부틸아크릴레이트 (polybutylacrylate), 폴리아크릴로니트릴 (polyacrylonitrile), 폴리비닐피롤리돈 (polyvinylpyrrolidone), 폴리비닐아세테이트 (polyvinylacetate), 에틸렌 비닐 아세테이트 공중합체 (polyethylene-co-vinyl acetate), 폴리에틸렌 (polyethylene), 폴리에틸렌옥사이드 (polyethylene oxide), 폴리아릴레이트 (polyarylate), 셀룰로오스 아세테이트 (cellulose acetate), 셀룰로오스 아세테이트 부틸레이트 (cellulose acetate butyrate), 셀룰로오스 아세테이트 프로피오네이트 (cellulose acetate propionate), 시아노에틸풀루란 (cyanoethylpullulan), 시아노에틸폴리비닐알콜 (cyanoethylpolyvinylalcohol), 시아노에틸셀룰로오스 (cyanoethylcellulose), 시아노에틸수크로오스 (cyanoethylsucrose), 풀루란 (pullulan) 및 카르복실 메틸 셀룰로오스 (carboxyl methyl cellulose)로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물일 수 있으나, 이에만 한정하는 것은 아니다.The polymer binder may be polyvinylidene fluoride-hexafluorofluoropropylene (polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP)), polyvinylidene fluoride-chlorotrifluorofluoroethylene (polyvinylidene fluoride-co -chlorotrifluoroethylene, polyvinylidene fluoride-co-trichloroethylene, polymethylmethacrylate, polybutylacrylate, polyacrylonitrile, polyvinyl Pyrrolidone (polyvinylpyrrolidone), polyvinylacetate, ethylene vinyl-co-vinyl acetate, polyethylene, polyethylene oxide, polyarylate, cellulose acetate ( cellulose acetate), cellulose acetate butyrate, Cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinylalcohol, cyanoethylcellulose, cyanoethylsucrose, pullulan ( pullulan) and carboxyl methyl cellulose (carboxyl methyl cellulose) may be any one selected from the group consisting of, or a mixture of two or more thereof, but is not limited thereto.
다공성 코팅층에 있어서 고분자 바인더는, 상기 무기물 입자들 표면의 일부 또는 전체에 코팅되며, 상기 무기물 입자들은 밀착된 상태로 상기 고분자 바인더에 의해 서로 연결 및 고정되며, 상기 무기물 입자들 사이에 존재하는 빈 공간으로 인해 기공들이 형성되어 있는 것이 바람직하다. 즉, 다공성 코팅층의 무기물 입자들은 서로 밀착된 상태로 존재하며, 무기물 입자들이 밀착된 상태에서 생기는 빈 공간이 다공성 코팅층의 기공이 된다. 무기물 입자들 사이에 존재하는 빈 공간의 크기는 무기물 입자들의 평균 입경과 같거나 그보다 작은 것이 바람직하다.In the porous coating layer, the polymer binder is coated on a part or the entire surface of the inorganic particles, and the inorganic particles are connected and fixed to each other by the polymer binder in close contact with each other, and an empty space existing between the inorganic particles. Due to the pores are preferably formed. That is, the inorganic particles of the porous coating layer are in close contact with each other, and the empty space generated when the inorganic particles are in close contact with the pores of the porous coating layer. The size of the void space present between the inorganic particles is preferably equal to or smaller than the average particle diameter of the inorganic particles.
한편, 본 발명에서 사용될 수 있는 비수 전해액에 포함되는 전해질 염은 리튬염이다. 상기 리튬염은 리튬 이차전지용 전해액에 통상적으로 사용되는 것들이 제한 없이 사용될 수 있다. 예를 들어 상기 리튬염의 음이온으로는 F-, Cl-, Br-, I-, NO3 -, N(CN)2 -, BF4 -, ClO4 -, PF6 -, (CF3)2PF4 -, (CF3)3PF3 -, (CF3)4PF2 -, (CF3)5PF-, (CF3)6P-, CF3SO3 -, CF3CF2SO3 -, (CF3SO2)2N-, (FSO2)2N- , CF3CF2(CF3)2CO-, (CF3SO2)2CH-, (SF5)3C-, (CF3SO2)3C-, CF3(CF2)7SO3 -, CF3CO2 -, CH3CO2 -, SCN- 및 (CF3CF2SO2)2N-로 이루어진 군에서 선택된 어느 하나일 수 있다.On the other hand, the electrolyte salt contained in the nonaqueous electrolyte solution that can be used in the present invention is a lithium salt. The lithium salt may be used without limitation those conventionally used in the lithium secondary battery electrolyte. For example is the above lithium salt anion F -, Cl -, Br - , I -, NO 3 -, N (CN) 2 -, BF 4 -, ClO 4 -, PF 6 -, (CF 3) 2 PF 4 -, (CF 3) 3 PF 3 -, (CF 3) 4 PF 2 -, (CF 3) 5 PF -, (CF 3) 6 P -, CF 3 SO 3 -, CF 3 CF 2 SO 3 - , (CF 3 SO 2) 2 N -, (FSO 2) 2 N -, CF 3 CF 2 (CF 3) 2 CO -, (CF 3 SO 2) 2 CH -, (SF 5) 3 C -, ( CF 3 SO 2) 3 C - , CF 3 (CF 2) 7 SO 3 -, CF 3 CO 2 -, CH 3 CO 2 -, SCN - and (CF 3 CF 2 SO 2 ) 2 N -It may be any one selected from the group consisting of.
전술한 비수 전해액에 포함되는 유기 용매로는 리튬 이차전지용 전해액에 통상적으로 사용되는 것들을 제한 없이 사용할 수 있으며, 예를 들면 에테르, 에스테르, 아미드, 선형 카보네이트, 환형 카보네이트 등을 각각 단독으로 또는 2종 이상 혼합하여 사용할 수 있다.As the organic solvent included in the nonaqueous electrolyte described above, those conventionally used in the lithium secondary battery electrolyte may be used without limitation, and for example, ethers, esters, amides, linear carbonates, and cyclic carbonates may be used alone or in combination of two or more. It can be mixed and used.
그 중에서 대표적으로는 환형 카보네이트, 선형 카보네이트, 또는 이들의 혼합물인 카보네이트 화합물을 포함할 수 있다.Among them, carbonate compounds which are typically cyclic carbonates, linear carbonates, or mixtures thereof may be included.
상기 환형 카보네이트 화합물의 구체적인 예로는 에틸렌 카보네이트(ethylene carbonate, EC), 프로필렌 카보네이트(propylene carbonate, PC), 1,2-부틸렌 카보네이트, 2,3-부틸렌 카보네이트, 1,2-펜틸렌 카보네이트, 2,3-펜틸렌 카보네이트, 비닐렌 카보네이트, 비닐에틸렌 카보네이트 및 이들의 할로겐화물로 이루어진 군에서 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물이 있다. 이들의 할로겐화물로는 예를 들면, 플루오로에틸렌 카보네이트(fluoroethylene carbonate, FEC) 등이 있으며, 이에 한정되는 것은 아니다.Specific examples of the cyclic carbonate compound include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, vinylene carbonate, vinylethylene carbonate and any one selected from the group consisting of halides thereof or mixtures of two or more thereof. These halides include, for example, fluoroethylene carbonate (FEC), but are not limited thereto.
또한 상기 선형 카보네이트 화합물의 구체적인 예로는 디메틸 카보네이트(DMC), 디에틸 카보네이트(DEC), 디프로필 카보네이트, 에틸메틸 카보네이트(EMC), 메틸프로필 카보네이트 및 에틸프로필 카보네이트 로 이루어진 군에서 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물 등이 대표적으로 사용될 수 있으나, 이에 한정되는 것은 아니다.In addition, specific examples of the linear carbonate compounds may be any one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethylmethyl carbonate (EMC), methylpropyl carbonate and ethylpropyl carbonate. Mixtures of two or more of them may be representatively used, but are not limited thereto.
특히, 상기 카보네이트계 유기용매 중 환형 카보네이트인 에틸렌 카보네이트 및 프로필렌 카보네이트는 고점도의 유기용매로서 유전율이 높아 전해질 내의 리튬염을 보다 더 잘 해리시킬 수 있으며, 이러한 환형 카보네이트에 디메틸 카보네이트 및 디에틸 카보네이트와 같은 저점도, 저유전율 선형 카보네이트를 적당한 비율로 혼합하여 사용하면 보다 높은 전기 전도율을 갖는 전해액을 만들 수 있다.In particular, ethylene carbonate and propylene carbonate, which are cyclic carbonates among the carbonate-based organic solvents, are high viscosity organic solvents and have a high dielectric constant, so that they can dissociate lithium salts in the electrolyte better, and cyclic carbonates such as dimethyl carbonate and diethyl carbonate. By using a low viscosity, low dielectric constant linear carbonate mixed in an appropriate ratio it can be made an electrolyte having a higher electrical conductivity.
또한, 상기 유기 용매 중 에테르로는 디메틸 에테르, 디에틸 에테르, 디프로필 에테르, 메틸에틸 에테르, 메틸프로필 에테르 및 에틸프로필 에테르로 이루어진 군에서 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물을 사용할 수 있으나, 이에 한정되는 것은 아니다.In addition, as the ether in the organic solvent, any one selected from the group consisting of dimethyl ether, diethyl ether, dipropyl ether, methylethyl ether, methylpropyl ether, and ethylpropyl ether, or a mixture of two or more thereof may be used. It is not limited to this.
그리고 상기 유기 용매 중 에스테르로는 메틸 아세테이트, 에틸 아세테이트, 프로필 아세테이트, 메틸 프로피오네이트, 에틸 프로피오네이트, γ-부티로락톤, γ-발레로락톤, γ-카프로락톤, σ-발레로락톤 및 ε-카프로락톤으로 이루어진 군에서 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물을 사용할 수 있으나, 이에 한정되는 것은 아니다.And esters in the organic solvent include methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone and One or a mixture of two or more selected from the group consisting of ε-caprolactone may be used, but is not limited thereto.
상기 비수 전해액의 주입은 최종 제품의 제조 공정 및 요구 물성에 따라, 전기화학소자의 제조 공정 중 적절한 단계에서 행해질 수 있다. 즉, 전기화학소자 조립 전 또는 전기화학소자 조립 최종 단계 등에서 적용될 수 있다.The injection of the nonaqueous electrolyte may be performed at an appropriate step in the manufacturing process of the electrochemical device, depending on the manufacturing process and the required physical properties of the final product. That is, it may be applied before the electrochemical device assembly or the final step of the electrochemical device assembly.
이하, 본 발명을 구체적으로 설명하기 위해 실시예를 들어 상세하게 설명하기로 한다. 그러나, 본 발명에 따른 실시예는 여러 가지 다른 형태로 변형될 수 있으며, 본 발명의 범위가 아래에서 상술하는 실시예에 한정되는 것으로 해석되어서는 아니 된다. 본 발명의 실시예는 당업계에서 평균적인 지식을 가진 자에게 본 발명을 보다 완전하게 설명하기 위해서 제공되는 것이다.Hereinafter, the present invention will be described in detail with reference to Examples. However, embodiments according to the present invention can be modified in various other forms, the scope of the present invention should not be construed as limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.
애노드용 활물질 슬러리의 제조Preparation of Anode Active Material Slurry
(1) 실시예 1-1(1) Example 1-1
애노드 활물질로서, KSC1064 (SiO:C, Shin-Etsu社)와 MAG-V2 (인조흑연/천연흑연 혼합물, Hitachi chemical社)의 혼합물(KSC1064와 MAG-V2의 중량비는 1:2)을 사용하였고, 바인더로서 열가교성 고분자인 중량평균분자량이 450,000 정도의 폴리아크릴산(Sigma Aldrich社)과, 수계 바인더인 스타이렌 부타디엔 고무를 사용하였으며, 도전재로서 탄소나노튜브를 혼합하여, pH 3.3의 애노드용 활물질 슬러리를 제조하였으며, 물이 상기 바인더를 용해시키는 용매의 역할을 하였다. 이때, 상기 애노드 활물질, 바인더 및 도전재는 90:7:3의 중량비로 혼합되었으며, 상기 바인더는 스타이렌 부타디엔 고무와 폴리아크릴산의 중량비가 7:3이 되도록 조절하였다.As the anode active material, a mixture of KSC1064 (SiO: C, Shin-Etsu Co., Ltd.) and MAG-V2 (artificial graphite / natural graphite mixture, Hitachi Chemical Co., Ltd.) (weight ratio of KSC1064 and MAG-V2 is 1: 2) was used. As the binder, polyacrylic acid (Sigma Aldrich) having a weight average molecular weight of about 450,000 and a styrene butadiene rubber as an aqueous binder were used, and carbon nanotubes were mixed as a conductive material, and an anode active material slurry having a pH of 3.3 was used. Was prepared, and water served as a solvent for dissolving the binder. At this time, the anode active material, the binder and the conductive material were mixed in a weight ratio of 90: 7: 3, the binder was adjusted so that the weight ratio of styrene butadiene rubber and polyacrylic acid is 7: 3.
(2) 비교예 1-1(2) Comparative Example 1-1
애노드용 활물질 슬러리의 수소이온농도가 pH 7.3인 것을 제외하고 실시예 1과 동일한 방법으로 애노드용 활물질 슬러리를 제조하였다.An anode active material slurry was prepared in the same manner as in Example 1 except that the hydrogen ion concentration of the anode active material slurry was pH 7.3.
(3) 비교예 2-1(3) Comparative Example 2-1
고분자 바인더로서, 카르복시메틸 셀룰로오스를 사용한 것을 제외하고 실시예 1과 동일한 방법으로 애노드용 활물질 슬러리를 제조하였다.An anode active material slurry was prepared in the same manner as in Example 1 except that carboxymethyl cellulose was used as the polymer binder.
애노드용 활물질 슬러리의 점도 및 점탄성 평가Evaluation of Viscosity and Viscoelasticity of Anode Active Material Slurry
도 1은 본 발명의 실시예 및 비교예에 따른 애노드용 활물질 슬러리의 점탄성을 나타낸 그래프이다.1 is a graph showing viscoelastic properties of an active material slurry for anode according to Examples and Comparative Examples of the present invention.
도 1을 참조하면, 비교예 1-1 및 2-1의 경우 점성에 비해 탄성이 강한 고상 거동을 보이는 반면에, 실시예 1-1의 경우 전단 속도에 따른 점도가 낮고, 탄성에 비해 점성이 매우 높은 액상 거동을 발현하기 때문에, 실시예 1-1의 분산성이 가장 우수하다고 볼 수 있다.Referring to FIG. 1, in Comparative Examples 1-1 and 2-1, the elasticity of the solid phase is stronger than that of the viscosity, whereas in Example 1-1, the viscosity is low according to the shear rate and the viscosity is higher than the elasticity. Since it exhibits very high liquid phase behavior, it can be said that the dispersibility of Example 1-1 is the best.
반쪽 셀의 제조Preparation of Half Cells
(1) 실시예 1-2(1) Example 1-2
1) 애노드의 제조1) Preparation of the anode
상기 실시예 1-1에서 제조된 애노드용 활물질 슬러리를 통상적인 방법으로 구리(Cu) 호일 집전체에 코팅하여, 애노드를 제조하였다.The anode active material slurry prepared in Example 1-1 was coated on a copper (Cu) foil current collector in a conventional manner to prepare an anode.
2) 반쪽 셀의 제조2) Preparation of Half Cells
상기 제조된 애노드와 리튬 금속 사이에 폴리에틸렌 다공성 막을 개재시켜 만든 전극조립체를 이용하여 코인형 반쪽 셀을 제조하였다.A coin-type half cell was prepared using an electrode assembly made of a polyethylene porous membrane interposed between the anode and the lithium metal.
(2) 비교예 1-2(2) Comparative Example 1-2
애노드용 활물질 슬러리로서 비교예 1-1에서 제조된 애노드용 활물질 슬러리를 사용하는 것을 제외하고 실시예 1-2와 동일한 방법으로 코인형 반쪽 셀을 제조하였다.A coin-type half cell was prepared in the same manner as in Example 1-2 except for using the anode active material slurry prepared in Comparative Example 1-1 as the anode active material slurry.
(3) 비교예 2-2(3) Comparative Example 2-2
애노드용 활물질 슬러리로서 비교예 2-1에서 제조된 애노드용 활물질 슬러리를 사용하는 것을 제외하고 실시예 1-2와 동일한 방법으로 코인형 반쪽 셀을 제조하였다.A coin-type half cell was prepared in the same manner as in Example 1-2 except for using the anode active material slurry prepared in Comparative Example 2-1 as the anode active material slurry.
반쪽 셀의 사이클 특성 평가Cycle Characterization of Half Cells
상기 제조된 코인형 반쪽 셀을 이용하여, 연속적인 충방전 조건에서 용량을 측정하였다. 그리고, 사이클 전, 후에 따른 애노드의 퇴화 정도를 확인하기 위해 SEM을 통해 애노드의 표면을 관찰하였다.Using the coin-type half cell prepared above, the capacity was measured under continuous charge and discharge conditions. Then, the surface of the anode was observed through SEM to confirm the degree of degradation of the anode before and after the cycle.
도 2 및 도 3은 각각 본 발명의 실시예 1-2에 따라 제조된 초기 애노드와 70 사이클 후의 애노드 표면을 나타내고, 도 4 및 도 5는 각각 비교예 2-2에 따라 제조된 초기 애노드와 70 사이클 후의 애노드 표면을 나타낸다.2 and 3 show the initial anode prepared according to Examples 1-2 of the present invention and the anode surface after 70 cycles, respectively, and FIGS. 4 and 5 show the initial anode prepared according to Comparative Example 2-2 and 70 respectively. The anode surface after the cycle is shown.
비교예 2-2의 경우, 사이클 전에 이미 형성되어 있던 기공 또는 작은 크랙으로 인해 사이클 진행 동안 크랙의 길이가 길어지는 것을 확인할 수 있었다. 반면에 실시예 1-2의 경우에는 비교예 2-2의 경우에 비해 기공이나 크랙의 크기가 작게 형성되어 있으며, 사이클 진행 동안 크랙의 크기 변화가 현저히 작았으며, 오히려 기공의 크기가 작아지는 것을 확인할 수 있었다.In the case of Comparative Example 2-2, it was confirmed that the crack length is long during the course of the cycle due to small pores or small cracks already formed before the cycle. On the other hand, in the case of Example 1-2, the size of the pores or cracks is formed smaller than that of Comparative Example 2-2, and the change in the size of the cracks was significantly smaller during the cycle, and rather the size of the pores was smaller. I could confirm it.
즉, 비교예 2-2는, 사이클의 진행에 따른 애노드 활물질의 부피 팽창으로 인한 스트레스를 크랙의 크기가 증가되는 방향으로 해소하고, 실시예 1-2는, 기공의 크기가 감소하는 방향으로 스트레스를 해소하는 것으로 판단할 수 있다.That is, in Comparative Example 2-2, the stress due to the volume expansion of the anode active material with the progress of the cycle is solved in the direction of increasing the size of the crack, Example 1-2, the stress in the direction of decreasing the pore size It can be judged to solve the problem.
한편, 도 6은 실시예 1-2 및 비교예 2-2에 의해 제조된 코인형 반쪽 셀의 사이클 진행에 따른 용량 유지율을 나타낸다. 도 6을 참조하면, 70 사이클이 진행된 후, 실시예의 경우에는 94.2 %의 용량 유지율을 나타내었으나, 비교예의 경우 70.2 %의 용량 유지율을 나타내어 실시예에 비해 용량 유지율이 현저히 떨어졌음을 알 수 있다.On the other hand, Figure 6 shows the capacity retention rate according to the cycle progress of the coin-type half cell prepared in Example 1-2 and Comparative Example 2-2. Referring to FIG. 6, after 70 cycles, the capacity retention rate of 94.2% was shown in the case of the example, but the capacity retention rate of the comparative example was 70.2%.
이상의 설명은 본 발명의 기술 사상을 예시적으로 설명한 것에 불과한 것으로서, 본 발명이 속하는 기술 분야에서 통상의 지식을 가진 자라면 본 발명의 본질적인 특성에서 벗어나지 않는 범위에서 다양한 수정 및 변형이 가능할 것이다. 따라서, 본 발명에 개시된 실시예들은 본 발명의 기술 사상을 한정하기 위한 것이 아니라 설명하기 위한 것이고, 이러한 실시예에 의하여 본 발명의 기술 사상의 범위가 한정되는 것은 아니다. 본 발명의 보호범위는 아래의 청구범위에 의하여 해석되어야 하며, 그와 동등한 범위 내에 있는 모든 기술 사상은 본 발명의 권리범위에 포함되는 것으로 해석되어야 할 것이다.The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Claims (23)

  1. 열에 의해 가교되는 열가교성 고분자 바인더; 및A thermal crosslinkable polymer binder crosslinked by heat; And
    상기 열가교성 고분자 바인더를 용해시키는 용매;를 포함하며,And a solvent for dissolving the thermally crosslinkable polymer binder.
    수소이온농도가 pH 2.5 내지 pH 4.5인 애노드용 바인더 용액.A binder solution for anodes having a hydrogen ion concentration of pH 2.5 to pH 4.5.
  2. 제1항에 있어서,The method of claim 1,
    상기 애노드용 바인더 용액은, 수소이온농도가 pH 3.0 내지 pH 3.5인 것을 특징으로 하는 애노드용 바인더 용액.The anode binder solution, the binder solution for anode, characterized in that the hydrogen ion concentration is pH 3.0 to pH 3.5.
  3. 제1항에 있어서,The method of claim 1,
    상기 열가교성 고분자 바인더는, 작용기로서 카르복시기를 포함하는 것을 특징으로 하는 애노드용 바인더 용액.The thermally crosslinkable polymer binder, a binder solution for the anode, characterized in that it contains a carboxyl group as a functional group.
  4. 제3항에 있어서,The method of claim 3,
    작용기로서 카르복시기를 포함하는 상기 열가교성 고분자 바인더는, 폴리아크릴산인 것을 특징으로 하는 애노드용 바인더 용액.The binder solution for anodes, wherein the thermocrosslinkable polymer binder containing a carboxyl group as a functional group is polyacrylic acid.
  5. 제1항에 있어서,The method of claim 1,
    상기 용매는, 아세톤(acetone), 테트라 하이드로퓨란(tetra hydrofuran), 메틸렌 클로라이드(methylene chloride), 클로로포름(chloroform), 디메틸포름 아미드(dimethylform amide), N-메틸-2-피롤리돈(N-methyl-2-pyrrolidone, NMP), 시클로헥산(cyclohexane) 및 물로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물인 것을 특징으로 하는 애노드용 바인더 용액.The solvent may be acetone, tetra hydrofuran, methylene chloride, chloroform, dimethylform amide, N-methyl-2-pyrrolidone (N-methyl A binder solution for anodes, characterized in that any one selected from the group consisting of -2-pyrrolidone, NMP), cyclohexane and water or a mixture of two or more thereof.
  6. 제1항에 있어서,The method of claim 1,
    상기 애노드용 바인더 용액은, 수계 바인더를 더 포함하는 것을 특징으로 하는 애노드용 바인더 용액.The anode binder solution further comprises an aqueous binder.
  7. 제6항에 있어서,The method of claim 6,
    상기 열가교성 고분자 바인더와 상기 수계 바인더의 중량비가 2:8 내지 5:5인 것을 특징으로 하는 애노드용 바인더 용액.A binder solution for the anode, characterized in that the weight ratio of the thermal crosslinkable polymer binder and the aqueous binder is 2: 8 to 5: 5.
  8. 제7항에 있어서,The method of claim 7, wherein
    상기 열가교성 고분자 바인더와 상기 수계 바인더의 중량비가 2:8 내지 4:6인 것을 특징으로 하는 애노드용 바인더 용액.A binder solution for the anode, characterized in that the weight ratio of the thermal crosslinkable polymer binder and the aqueous binder is 2: 8 to 4: 6.
  9. 제6항에 있어서,The method of claim 6,
    상기 수계 바인더는, 스타이렌 부타디엔 고무, 카르복시메틸셀룰로오스, 폴리테트라풀루오로에틸렌, 폴리에틸렌, 폴리프로필렌, 에틸렌프로필렌공중합체, 폴리부타디엔, 부틸고무, 불소고무, 폴리에틸렌옥사이드, 폴리비닐피롤리돈, 폴리에피클로로히드린, 폴리포스파겐, 폴리아크릴로니트릴, 폴리스타이렌, 에틸렌프로필렌디엔공중합체, 폴리비닐피리딘, 클로로설폰화폴리에틸렌, 라텍스, 폴리에스테르수지, 아크릴수지, 페놀수지, 에폭시수지, 폴리비닐알콜 및 히드록시프로필셀룰로오스로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물인 것을 특징으로 하는 애노드용 바인더 용액.The aqueous binder is styrene butadiene rubber, carboxymethyl cellulose, polytetrafluoroethylene, polyethylene, polypropylene, ethylene propylene copolymer, polybutadiene, butyl rubber, fluorine rubber, polyethylene oxide, polyvinylpyrrolidone, poly Epichlorohydrin, polyphosphagen, polyacrylonitrile, polystyrene, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol and A binder solution for an anode, characterized in that any one or a mixture of two or more selected from the group consisting of hydroxypropyl cellulose.
  10. 애노드용 바인더 용액; 및Binder solution for anode; And
    상기 애노드용 바인더 용액에 분산되는 애노드 활물질;을 포함하되,Including; an anode active material dispersed in the anode binder solution;
    상기 애노드용 바인더 용액은, 제1항의 애노드용 바인더 용액인 것을 특징으로 하는 애노드용 활물질 슬러리.The anode binder solution is an anode active material slurry, characterized in that the anode binder solution.
  11. 제10항에 있어서,The method of claim 10,
    상기 애노드용 활물질 슬러리의 수소이온농도는 pH 2.5 내지 pH 4.5인 것을 특징으로 하는 애노드용 활물질 슬러리.Hydrogen ion concentration of the anode active material slurry is an active material slurry for the anode, characterized in that pH 2.5 to pH 4.5.
  12. 제11항에 있어서,The method of claim 11,
    상기 애노드용 활물질 슬러리의 수소이온농도는 pH 3.0 내지 pH 3.5인 것을 특징으로 하는 애노드용 활물질 슬러리.Hydrogen ion concentration of the anode active material slurry is an active material slurry for the anode, characterized in that pH 3.0 to pH 3.5.
  13. 제10항에 있어서,The method of claim 10,
    상기 애노드용 활물질 슬러리의 고형분량은 상기 애노드용 활물질 슬러리 중 43 내지 50 중량%인 것을 특징으로 하는 애노드용 활물질 슬러리.Solid content of the anode active material slurry is an anode active material slurry, characterized in that 43 to 50% by weight of the anode active material slurry.
  14. 제10항에 있어서,The method of claim 10,
    상기 애노드 활물질은, 리튬 금속, 탄소재, 금속 화합물, 금속 산화물 또는 이들의 혼합물을 포함하는 것을 특징으로 하는 애노드용 활물질 슬러리.The anode active material, the anode active material slurry, characterized in that it comprises a lithium metal, a carbon material, a metal compound, a metal oxide or a mixture thereof.
  15. 제14항에 있어서,The method of claim 14,
    상기 금속 화합물은, Si, Ge, Sn, Pb, P, Sb, Bi, Al, Ga, In, Ti, Mn, Fe, Co, Ni, Cu, Zn, Ag, Mg, Sr, 및 Ba로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물인 것을 특징으로 하는 애노드용 활물질 슬러리.The metal compound is a group consisting of Si, Ge, Sn, Pb, P, Sb, Bi, Al, Ga, In, Ti, Mn, Fe, Co, Ni, Cu, Zn, Ag, Mg, Sr, and Ba An active material slurry for anode, characterized in that any one or a mixture of two or more thereof selected from.
  16. 제14항에 있어서,The method of claim 14,
    상기 금속 산화물은, 규소 산화물, 주석 산화물, 티탄 산화물 및 리튬 바나듐계 산화물로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물인 것을 특징으로 하는 애노드용 활물질 슬러리.The metal oxide is any one selected from the group consisting of silicon oxide, tin oxide, titanium oxide and lithium vanadium oxide, or a mixture of two or more thereof.
  17. 집전체; 및Current collector; And
    상기 집전체의 일면 또는 양면 상에 형성되어 있으며, 제10항 내지 제16항 중 어느 한 항에 따른 애노드용 활물질 슬러리의 건조단계 결과물로 이루어진 애노드 활물질층;을 포함하는 애노드.An anode comprising: an anode active material layer formed on one surface or both surfaces of the current collector, the anode active material layer made of the result of the drying step of the active material slurry for anode according to any one of claims 10 to 16.
  18. 제17항에 있어서,The method of claim 17,
    상기 건조단계에 의해, 상기 용매가 제거되고, 상기 열가교성 고분자 바인더가 서로 가교되어 가교 고분자 네트워크를 형성하는 것을 특징으로 하는 애노드.By the drying step, the solvent is removed, the thermal crosslinkable polymer binder is crosslinked with each other to form a crosslinked polymer network.
  19. 제18항에 있어서,The method of claim 18,
    상기 건조단계는, 120 내지 140 ℃의 온도에서 1차 건조를 통해 상기 용매를 제거하고, 진공상태의 140 내지 160 ℃의 온도에서 2차 건조를 통해 상기 가교 고분자 네트워크를 형성하는 것을 특징으로 하는 애노드.The drying step, the anode to remove the solvent through the first drying at a temperature of 120 to 140 ℃, and to form the cross-linked polymer network through the second drying at a temperature of 140 to 160 ℃ in a vacuum state .
  20. 집전체; 및Current collector; And
    상기 집전체의 일면 또는 양면 상에 형성되어 있는 애노드 활물질층;을 포함하는 애노드로서,An anode comprising; an anode active material layer formed on one or both surfaces of the current collector,
    상기 애노드 활물질층은, 애노드 활물질 및 고분자 바인더를 포함하고,The anode active material layer includes an anode active material and a polymer binder,
    상기 고분자 바인더는, 열에 의해 가교되는 열가교성 고분자 바인더 및 수계 바인더의 혼합물이며,The polymer binder is a mixture of a thermal crosslinkable polymer binder and an aqueous binder crosslinked by heat,
    상기 열가교성 고분자 바인더와 상기 수계 바인더의 중량비가 2:8 내지 5:5이고,The weight ratio of the thermal crosslinkable polymer binder and the aqueous binder is 2: 8 to 5: 5,
    상기 열가교성 고분자는 서로 가교되어 가교 고분자 네트워크를 형성하는 것을 특징으로 하는 애노드.The thermal crosslinkable polymer is crosslinked with each other to form a crosslinked polymer network.
  21. 제20항에 있어서,The method of claim 20,
    상기 열가교성 고분자 바인더는, 폴리아크릴산이고, 상기 수계 바인더는, 스타이렌 부타디엔 고무인 것을 특징으로 하는 애노드.The thermally crosslinkable polymer binder is polyacrylic acid, and the aqueous binder is styrene butadiene rubber.
  22. 캐소드, 애노드, 상기 캐소드와 상기 애노드 사이에 개재된 세퍼레이터 및 비수 전해액을 포함하는 전기화학소자에 있어서,In the electrochemical device comprising a cathode, an anode, a separator interposed between the cathode and the anode and a nonaqueous electrolyte,
    상기 애노드는, 제17항의 애노드인 것을 특징으로 하는 전기화학소자.The anode is an electrochemical device, characterized in that the anode of claim 17.
  23. 제22항에 있어서,The method of claim 22,
    상기 전기화학소자는, 리튬 이차전지인 것을 특징으로 하는 전기화학소자.The electrochemical device is an electrochemical device, characterized in that the lithium secondary battery.
PCT/KR2014/005376 2013-06-18 2014-06-18 Binder solution for anode, active material slurry for anode comprising same, anode using said active material slurry, and electrochemical device comprising same WO2014204214A1 (en)

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CN201480034381.3A CN105308780B (en) 2013-06-18 2014-06-18 A kind of cathode and the electrochemical device containing the cathode
US14/591,135 US9515321B2 (en) 2013-06-18 2015-01-07 Binder solution for anode, active material slurry for anode comprising the binder solution, anode using the slurry and electrochemical device comprising the anode

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116093331A (en) * 2023-04-06 2023-05-09 宁德新能源科技有限公司 Secondary battery and electronic device
CN116111100A (en) * 2023-04-12 2023-05-12 深圳好电科技有限公司 Lithium ion battery negative electrode material, preparation method thereof and lithium ion battery

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20020018393A (en) * 2000-09-01 2002-03-08 김순택 A Lithium Sulfur Secondary batteries using multi-layer separator
KR20040009328A (en) * 2002-07-23 2004-01-31 삼성에스디아이 주식회사 Electrode for lithium sulfur batteries comprising curable binder and lithium sulfur batteries comprising the same
KR20060110235A (en) * 2005-04-19 2006-10-24 주식회사 엘지화학 Safety-improved electrode by introducing crosslinkable polymer and electrochemical device comprising the same
KR20090119895A (en) * 2007-03-16 2009-11-20 세키스이가가쿠 고교가부시키가이샤 Electrode binder, electrode, membrane-electrode assembly, and solid polymer fuel cell
KR20110060094A (en) * 2009-11-30 2011-06-08 현대자동차주식회사 Electrode for polymer electrolyte membrane fuel cell and method for manufacturing membrane-electrode assembly using the same

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20020018393A (en) * 2000-09-01 2002-03-08 김순택 A Lithium Sulfur Secondary batteries using multi-layer separator
KR20040009328A (en) * 2002-07-23 2004-01-31 삼성에스디아이 주식회사 Electrode for lithium sulfur batteries comprising curable binder and lithium sulfur batteries comprising the same
KR20060110235A (en) * 2005-04-19 2006-10-24 주식회사 엘지화학 Safety-improved electrode by introducing crosslinkable polymer and electrochemical device comprising the same
KR20090119895A (en) * 2007-03-16 2009-11-20 세키스이가가쿠 고교가부시키가이샤 Electrode binder, electrode, membrane-electrode assembly, and solid polymer fuel cell
KR20110060094A (en) * 2009-11-30 2011-06-08 현대자동차주식회사 Electrode for polymer electrolyte membrane fuel cell and method for manufacturing membrane-electrode assembly using the same

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116093331A (en) * 2023-04-06 2023-05-09 宁德新能源科技有限公司 Secondary battery and electronic device
CN116111100A (en) * 2023-04-12 2023-05-12 深圳好电科技有限公司 Lithium ion battery negative electrode material, preparation method thereof and lithium ion battery
CN116111100B (en) * 2023-04-12 2023-09-19 深圳好电科技有限公司 Lithium ion battery negative electrode material, preparation method thereof and lithium ion battery

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