WO2018106078A1 - Electrolyte for lithium secondary battery and lithium secondary battery comprising same - Google Patents

Electrolyte for lithium secondary battery and lithium secondary battery comprising same Download PDF

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Publication number
WO2018106078A1
WO2018106078A1 PCT/KR2017/014432 KR2017014432W WO2018106078A1 WO 2018106078 A1 WO2018106078 A1 WO 2018106078A1 KR 2017014432 W KR2017014432 W KR 2017014432W WO 2018106078 A1 WO2018106078 A1 WO 2018106078A1
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Prior art keywords
secondary battery
lithium secondary
electrolyte
group
formula
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PCT/KR2017/014432
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French (fr)
Korean (ko)
Inventor
오정우
안경호
이철행
이정훈
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주식회사 엘지화학
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Priority to EP17878254.6A priority Critical patent/EP3531491B1/en
Priority to PL17878254T priority patent/PL3531491T3/en
Priority to US16/078,151 priority patent/US10553903B2/en
Priority to JP2018565316A priority patent/JP6775843B2/en
Priority to CN201780015219.0A priority patent/CN108886165B/en
Priority claimed from KR1020170168433A external-priority patent/KR102102985B1/en
Publication of WO2018106078A1 publication Critical patent/WO2018106078A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/02—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques
    • C08J3/03—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in aqueous media
    • C08J3/075—Macromolecular gels
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L71/00—Compositions of polyethers obtained by reactions forming an ether link in the main chain; Compositions of derivatives of such polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L71/00—Compositions of polyethers obtained by reactions forming an ether link in the main chain; Compositions of derivatives of such polymers
    • C08L71/08—Polyethers derived from hydroxy compounds or from their metallic derivatives
    • C08L71/10—Polyethers derived from hydroxy compounds or from their metallic derivatives from phenols
    • C08L71/12—Polyphenylene oxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0565—Polymeric materials, e.g. gel-type or solid-type
    • 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
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0568—Liquid materials characterised by the solutes
    • 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
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0569—Liquid materials characterised by the solvents
    • 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 electrolyte for a lithium secondary battery having improved high temperature durability and a lithium secondary battery including the same.
  • the lithium secondary battery generally includes a positive electrode and a negative electrode including an electrode active material capable of inserting / releasing lithium ions, and an electrolyte which is a transfer medium of lithium ions.
  • a liquid electrolyte containing a non-aqueous organic solvent in which an electrolyte salt is dissolved or a gel polymer electrolyte further comprising a matrix polymer in the liquid electrolyte is used.
  • the electrolyte is decomposed during charging and discharging of the lithium secondary battery, or gas may be generated inside the secondary battery by side reaction between the electrode and the electrolyte, and such gas generation is further increased during high temperature storage.
  • This continuously generated gas not only causes deformation of the battery, such as causing an increase in the internal pressure of the battery, thereby expanding the thickness of the battery, but also locally changing the adhesion on the electrode surface of the battery, so that the electrode reaction does not occur identically on the entire electrode surface. It can cause problems.
  • lithium secondary battery in order to improve the stability and high output characteristics of the lithium secondary battery, it is necessary to develop a lithium secondary battery having improved stability by suppressing gas generation and exothermic reaction during high temperature storage and overcharging.
  • the present invention has been made to solve such a problem
  • a second technical problem of the present invention is to provide a lithium secondary battery having improved stability at high temperature storage and overcharge by including the electrolyte for a lithium secondary battery.
  • R is an aliphatic hydrocarbon group or an aromatic hydrocarbon group
  • R 1 to R 3 are each independently an alkylene group having 1 to 5 carbon atoms unsubstituted or substituted with fluorine,
  • R 4 is an alkylene group having 1 to 4 carbon atoms
  • R ' is hydrogen or an alkyl group having 1 to 3 carbon atoms
  • a 1 to 3
  • n is the number of repeat units
  • n is an integer of any one of 1 to 75.
  • the aliphatic hydrocarbon group may be substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms; A substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms containing an isocyanate group (NCO); A substituted or unsubstituted cycloalkenylene group having 4 to 20 carbon atoms; And at least one alicyclic hydrocarbon group selected from the group consisting of a substituted or unsubstituted heterocycloalkylene group having 2 to 20 carbon atoms, or a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms; Substituted or unsubstituted C1-C20 alkylene group containing an isocyanate group (NCO); A substituted or unsubstituted alkoxylene group having 1 to 20 carbon atoms; A substituted or unsubstituted alkenylene group having 2 to 20 carbon atoms; And a linear
  • the aromatic hydrocarbon group is substituted or unsubstituted arylene group having 6 to 20 carbon atoms; Or a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms.
  • the oligomer represented by Formula 1 may be an oligomer represented by Formula 1a.
  • R is an aliphatic hydrocarbon group or an aromatic hydrocarbon group
  • R 1 is an alkylene group having 1 to 5 carbon atoms substituted or unsubstituted with fluorine,
  • n1 is the number of repeat units
  • n1 is an integer of any one of 1-75.
  • the oligomer represented by Formula 1a may be an oligomer represented by Formula 1a-1.
  • n2 is the number of repeat units
  • n2 is an integer of any one of 20-75.
  • the oligomer represented by Chemical Formula 1 may be included in an amount of 0.5 wt% to 20 wt%, specifically 0.5 wt% to 15 wt%, based on the total weight of the lithium secondary battery electrolyte.
  • the lithium secondary battery electrolyte may be a liquid electrolyte.
  • the lithium secondary battery electrolyte may be a gel polymer electrolyte.
  • the polymer derived from the oligomer represented by Formula 1 may be a matrix polymer formed in a three-dimensional structure by polymerization of the oligomer represented by Formula 1 in the presence of a polymerization initiator.
  • the gel polymer electrolyte may further include inorganic particles.
  • Such inorganic particles include BaTiO 3 , BaTiO 3 , Pb (Zr x Ti 1-x ) O 3 (0 ⁇ x ⁇ 1) (PZT), Pb 1- b La b Zr 1-c Ti c O 3 (PLZT, where , 0 ⁇ b ⁇ 1, 0 ⁇ c ⁇ 1), Pb (Mg 1/3 Nb 2/3 ) O 3 -PbTiO 3 (PMN-PT), Hafnia (HfO 2 ), SrTiO 3 , SnO 2 , It may include a single or a mixture of two or more selected from the group consisting of CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 , Al 2 O 3 , TiO 2 , SiC and mixtures thereof.
  • the inorganic particles may be included in 10% by weight to 25% by weight based on the total weight of the electrolyte for a lithium secondary battery.
  • a cathode interposed between the cathode, the anode, the cathode and the anode, and
  • the lithium secondary battery electrolyte may be a liquid electrolyte or a gel polymer electrolyte.
  • the present invention by including oligomers having hydrophilic and hydrophobic functional groups, the surface tension with the electrode surface can be lowered to improve wettability, and a stable ion conductive film is formed on the electrode surface during initial charging.
  • a lithium secondary battery electrolyte having improved high temperature durability by preventing electrolyte side reactions and oxidation reactions during high temperature storage and overcharge.
  • the present invention provides a lithium secondary battery having such a lithium secondary battery electrolyte, thereby suppressing an exothermic reaction during high temperature storage and overcharging, thereby improving a lithium secondary battery having improved overall performance such as stability.
  • Example 1 is a graph showing the gas content generated from the lithium secondary battery of Example 1 and Comparative Example 1 according to Experimental Example 2 of the present invention.
  • FIG. 2 is a graph showing the gas content generated from the lithium secondary battery of Examples 5 and 6 and Comparative Example 3 according to Experimental Example 3 of the present invention.
  • Example 3 is a graph showing the results of evaluation of the oxidation stability of the gel polymer electrolyte of Example 5 and the liquid electrolyte of Comparative Example 1 according to Experimental Example 4 of the present invention.
  • Example 4 is a graph showing the results of evaluating the reduction stability of the gel polymer electrolyte of Example 6 and the liquid electrolyte of Comparative Example 2 according to Experimental Example 4 of the present invention.
  • Example 5 is a graph showing the results of the performance evaluation at room temperature (25 °C) of the lithium secondary battery of Example 5 and Comparative Example 3 according to Experimental Example 5 of the present invention.
  • FIG. 6 is a graph illustrating performance evaluation results at low temperatures ( ⁇ 10 ° C.) of lithium secondary batteries of Example 5 and Comparative Example 3 according to Experimental Example 6 of the present invention.
  • FIG. 6 is a graph illustrating performance evaluation results at low temperatures ( ⁇ 10 ° C.) of lithium secondary batteries of Example 5 and Comparative Example 3 according to Experimental Example 6 of the present invention.
  • Example 7 is a graph illustrating thermal stability evaluation results of the lithium secondary battery of Example 5 and Comparative Example 3 according to Experimental Example 7 of the present invention.
  • R is an aliphatic hydrocarbon group or an aromatic hydrocarbon group
  • R 1 to R 3 are each independently an alkylene group having 1 to 5 carbon atoms unsubstituted or substituted with fluorine,
  • R 4 is an alkylene group having 1 to 4 carbon atoms
  • R ' is hydrogen or an alkyl group having 1 to 3 carbon atoms
  • a 1 to 3
  • n is the number of repeat units
  • n is an integer of any one of 1 to 75.
  • the lithium salt may be used without limitation those conventionally used in the electrolyte for lithium secondary batteries, for example, includes Li + as the cation of the lithium salt anion include F -, Cl -, Br - , I -, NO 3 -, N (CN) 2 -, BF 4 -, ClO 4 -, AlO 4 -, AlCl 4 -, PF 6 -, SbF 6 - , AsF 6 -, BF 2 C 2 O 4 -, BC 4 O 8 -, PF 4 C 2 O 4 -, PF 2 C 4 O 8 -, (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 -, C 4 F 9 SO 3 -, CF 3 CF 2 SO 3 -, (CF
  • the lithium salt is LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiPF 6 , LiCF 3 SO 3 , LiCH 3 CO 2 , LiCF 3 CO 2 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , LiAlO 4 , and LiCH 3 SO 3
  • It may include a single or a mixture of two or more selected from the group consisting of, in addition to these LiBTI (lithium bisperfluoroethanesulfonimide, LiN (SO 2 C 2 F) commonly used in the electrolyte of the lithium secondary battery 5 ) without limitation lithium salts such as lithium imide salts represented by 2 ), LiFSI (lithium fluorosulfonyl imide, LiN (SO 2 F) 2 ), and LiTFSI (lithium (bis) trifluoromethanesulfonimide, LiN (SO 2 CF 3 ) 2 ) Can be used.
  • the lithium salt is a single or two selected from the group consisting of LiPF 6 , LiBF 4 , LiCH 3 CO 2 , LiCF 3 CO 2 , LiCH 3 SO 3 , LiFSI, LiTFSI and LiN (C 2 F 5 SO 2 ) 2 It may contain a mixture of the above.
  • the lithium salt may be appropriately changed within a range generally available, and specifically, may be included in the electrolyte for lithium secondary batteries at 0.8 M to 3M, specifically 1.0M to 2.5M. If the concentration of the lithium salt is greater than 3M, the viscosity of the electrolyte may be increased to reduce the lithium ion migration effect.
  • the organic solvent in the electrolyte for a lithium secondary battery according to an embodiment of the present invention, if the organic solvent can minimize the decomposition by the oxidation reaction, etc. in the charge and discharge process of the secondary battery, and if it can exhibit the desired characteristics with additives no limits.
  • the organic solvent may be used alone or in combination of two or more of an ether solvent, an ester solvent, an amide solvent, and the like.
  • 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.
  • the ester solvent may include at least one compound selected from the group consisting of a cyclic carbonate compound, a linear carbonate compound, a linear ester compound, and a cyclic ester compound.
  • cyclic carbonate compound examples include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, and 1,2-pentylene carbonate. , 2,3-pentylene carbonate, vinylene carbonate and fluoroethylene carbonate (FEC), or any one or a mixture of two or more thereof.
  • linear carbonate compound examples include dimethyl carbonate (dimethyl carbonate, DMC), diethyl carbonate (diethyl carbonate, DEC), dipropyl carbonate, ethyl methyl carbonate (EMC), methylpropyl carbonate and ethylpropyl carbonate Any one selected from, or a mixture of two or more thereof may be representatively used, but is not limited thereto.
  • the linear ester compound is any one selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, and butyl propionate.
  • the above mixture and the like can be used representatively, but is not limited thereto.
  • the cyclic ester compound is any one selected from the group consisting of ⁇ -butyrolactone, ⁇ -valerolactone, ⁇ -caprolactone, ⁇ -valerolactone, ⁇ -caprolactone, or two or more thereof Mixtures may be used, but are not limited thereto.
  • the cyclic carbonate-based compound is a high viscosity organic solvent and has a high dielectric constant, and thus may be preferably used because it dissociates lithium salts in the electrolyte.
  • the cyclic carbonate-based compound has low viscosity and low viscosity such as dimethyl carbonate and diethyl carbonate
  • an electrolyte having a high electrical conductivity can be made, which can be used more preferably.
  • the lithium secondary battery electrolyte according to an embodiment of the present invention may include an oligomer represented by the formula (1).
  • the oligomer represented by the formula (1) exhibits a balanced affinity with the positive electrode or separator (SRS layer) and the negative electrode or separator fabric in the secondary battery is electrochemically stable, which is a great help in improving lithium secondary battery performance.
  • the oligomer represented by the formula (1) contains an acrylate-based functional group which is a hydrophilic part capable of forming crosslinking at both ends thereof, and also contains a fluorine-substituted ethylene group which is a hydrophobic part, and thus is an interface in a battery.
  • the interfacial resistance can be lowered by maintaining balanced affinity with the positive electrode, the negative electrode, and the separator (SRS layer), respectively. Therefore, the electrolyte for a lithium secondary battery including the oligomer represented by Chemical Formula 1 may further improve the wettability effect.
  • the oligomer represented by the formula (1) has the ability to dissociate lithium salts to improve the lithium ion mobility, in particular containing an alkyl group substituted with fluorine at the end, and at the same time repeating Since it contains a fluorine-substituted ethylene group which is very chemically stable and has low reactivity with Li ions, a stable ion conductive film is formed on the surface of the electrode during initial charging, so that the electrolyte and lithium ions (Li + ) and Side reactions, electrolyte oxidation reactions and decomposition reactions of lithium salts can be controlled.
  • a polymer having an alkylene oxide skeleton such as ethylene oxide, propylene oxide, or butylene oxide which has been commercialized at the time of preparing a gel polymer electrolyte, or a block copolymer having a dialkyl siloxane, a fluorosiloxane, or a unit thereof;
  • the secondary battery electrolyte of the present invention including the oligomer represented by Chemical Formula 1 in place of the graft polymer may reduce electrolyte side reactions and oxidation reactions, thereby realizing an interfacial stability effect between the electrode and the electrolyte, thereby improving high temperature durability.
  • the aliphatic hydrocarbon group may be substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms; A substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms containing an isocyanate group (NCO); A substituted or unsubstituted cycloalkenylene group having 4 to 20 carbon atoms; And at least one alicyclic hydrocarbon group selected from the group consisting of a substituted or unsubstituted heterocycloalkylene group having 2 to 20 carbon atoms, or a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms; Substituted or unsubstituted C1-C20 alkylene group containing an isocyanate group (NCO); A substituted or unsubstituted alkoxylene group having 1 to 20 carbon atoms; A substituted or unsubstituted alkenylene group having 2 to 20 carbon atoms; And a linear
  • the aromatic hydrocarbon group is substituted or unsubstituted arylene group having 6 to 20 carbon atoms; Or a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms.
  • the oligomer represented by Formula 1 may be an oligomer represented by Formula 1a.
  • R is an aliphatic hydrocarbon group or an aromatic hydrocarbon group
  • R 1 is an alkylene group having 1 to 5 carbon atoms substituted or unsubstituted with fluorine,
  • n1 is the number of repeat units
  • n1 is an integer of any one of 1-75.
  • the oligomer represented by Formula 1a may be an oligomer represented by Formula 1a-1.
  • n2 is the number of repeat units
  • n2 is an integer of any one of 20-75.
  • the oligomer represented by Chemical Formula 1 may be included in an amount of 0.5 wt% to 20 wt%, specifically 0.5 wt% to 15 wt%, and more specifically 0.5 wt% to 10 wt%, based on the total weight of the lithium secondary battery electrolyte.
  • a gel polymer electrolyte having a stable network structure may be prepared, and when the content of the oligomer is 20% by weight or less, an increase in resistance due to the addition of an excessive oligomer is prevented to ensure wettability. At the same time, it is possible to prevent the disadvantages such as lowering the ion conductivity by improving the movement restriction of lithium ions.
  • the weight average molecular weight (MW) of the oligomer represented by Formula 1 may be adjusted by the number of repeating units, about 1,000 g / mol 100,000 g / mol, specifically 1,000 g / mol to 50,000 g / mol, More specifically, it may be 2,000 g / mol to 7,000 g / mol.
  • the weight average molecular weight of the oligomer is in the above range, it is possible to effectively form a polymer matrix by the appropriate oligomer molecular weight.
  • various functional groups can be easily substituted as necessary, various various performance improvement effects can be obtained.
  • the weight average molecular weight of the oligomer is less than 1,000 g / mol, since it is difficult to form a stable polymer network, its own electrochemical stability and the role of a surfactant cannot be expected, and the weight average molecular weight exceeds 100,000 g / mol. In other words, the oligomer properties are rigid and the affinity with the electrolyte solvent is lowered due to the increase in viscosity, so that the solubility is lowered.
  • the weight average molecular weight may mean a conversion value for standard polystyrene measured by gel permeation chromatography (GPC), and unless otherwise specified, molecular weight may mean weight average molecular weight.
  • GPC gel permeation chromatography
  • the GPC conditions are measured using Agilent's 1200 series, and the column used may be an Agilent PL mixed B column, and the solvent may be THF.
  • the lithium secondary battery electrolyte according to one embodiment of the present invention includes the oligomer represented by Formula 1, the lithium secondary battery electrolyte of the present invention may be a liquid electrolyte.
  • the lithium secondary battery electrolyte according to an embodiment of the present invention includes a polymer derived from the oligomer represented by the formula (1)
  • the lithium secondary battery electrolyte may be a gel polymer electrolyte.
  • the polymer derived from the oligomer represented by Formula 1 may be a matrix polymer formed in a three-dimensional structure by polymerization of the oligomer represented by Formula 1 in the presence of a polymerization initiator.
  • a polymerization initiator used to form a gel may be a conventional polymerization initiator capable of generating radicals by heat and light used in preparing a conventional gel polymer electrolyte. Can be used without limitation.
  • the polymerization initiator may be decomposed by heat in the secondary battery, for example, but not limited to 30 ° C. to 100 ° C., specifically 60 ° C. to 80 ° C., or may be decomposed at room temperature (5 ° C. to 30 ° C.) to form radicals.
  • the polymerization initiator may be included in about 0.01 parts by weight to about 20 parts by weight, specifically 5 parts by weight based on 100 parts by weight of the total oligomer, and if included in the above range to facilitate the gelling reaction, the composition is injected into a battery It is possible to prevent the gelation occurs during the operation, or the unreacted polymerization initiator remains after the polymerization reaction to cause side reactions.
  • some polymerization initiators may generate nitrogen or oxygen gas in the process of generating radicals by heat or the like. This gas generation is often lead to gas trap or gas bubbling phenomenon in the gel polymer electrolyte formation process. This gas generation causes a defect in the gel polymer electrolyte, resulting in a decrease in electrolyte quality. Therefore, when the polymerization initiator is included in the above range, it is possible to more effectively prevent the disadvantages such as the generation of a large amount of gas.
  • some polymerization initiators may generate nitrogen or oxygen gas in the process of generating radicals by heat or the like. This gas generation is often lead to gas trap or gas bubbling phenomenon in the gel polymer electrolyte formation process. This gas generation causes a defect in the gel polymer electrolyte, resulting in electrolyte quality deterioration. Therefore, when the polymerization initiator is included in the above range, it is possible to more effectively prevent the disadvantages such as the generation of a large amount of gas.
  • the gel polymer electrolyte of the present invention may have a gel content of about 1% by weight or more, specifically about 20% by weight or more at 25 ° C.
  • the gel polymer electrolyte of the present invention may further include inorganic particles.
  • the inorganic particles may be impregnated in the polymer network to allow the high viscosity solvent to penetrate well through the pores formed by the void space between the inorganic particles. That is, by including the inorganic particles, it is possible to obtain an effect of further improving the wettability to a high viscosity solvent by affinity between the polar substances and capillary phenomenon.
  • inorganic particles having a high dielectric constant and which do not generate an oxidation and / or reduction reaction in an operating voltage range of the lithium secondary battery (for example, 0 to 5V based on Li / Li + ) may be used.
  • the inorganic particles are representative examples of BaTiO 3 , BaTiO 3 , Pb (Zr x Ti 1-x ) O 3 (0 ⁇ x ⁇ 1) (PZT), Pb 1 ⁇ b La b having a dielectric constant of 5 or more.
  • Zr 1 - c Ti c O 3 (PLZT, where 0 ⁇ b ⁇ 1, 0 ⁇ c ⁇ 1), Pb (Mg 1/3 Nb 2/3 ) O 3 -PbTiO 3 (PMN-PT), half Single substance selected from the group consisting of nia (HfO 2 ), SrTiO 3 , SnO 2 , CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 , Al 2 O 3 , TiO 2 , SiC and mixtures thereof Or a mixture of two or more thereof.
  • nia HfO 2
  • SrTiO 3 SnO 2 , CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 , Al 2 O 3 , TiO 2 , SiC and mixtures thereof Or a mixture of two or more thereof.
  • inorganic particles having lithium ion transfer ability that is, lithium phosphate (Li 3 PO 4 ), lithium titanium phosphate (Li d Ti e (PO 4 ) 3 , 0 ⁇ d ⁇ 2, 0 ⁇ e ⁇ 3 ), Lithium aluminum titanium phosphate (Li a1 Al b1 Ti c1 (PO 4 ) 3 , 0 ⁇ a1 ⁇ 2, 0 ⁇ b1 ⁇ 1, 0 ⁇ c1 ⁇ 3), 14Li 2 O-9Al 2 O 3 -38TiO 2- (LiAlTiP) a2 O b2 series glass such as 39P 2 O 5 (0 ⁇ a2 ⁇ 4, 0 ⁇ b2 ⁇ 13), lithium lanthanum titanate (Li a3 La b3 TiO 3 , 0 ⁇ a3 ⁇ 2, 0 ⁇ b3 ⁇ 3), Li 3 .
  • lithium phosphate Li 3 PO 4
  • lithium titanium phosphate Li d Ti e (PO
  • the inorganic particles may be included in 10% by weight to 25% by weight based on the total weight of the electrolyte for a lithium secondary battery.
  • the inorganic particle content is less than 10% by weight, it is difficult to expect an effect of improving wetting in a high viscosity solvent, and when it exceeds 25% by weight, it may cause a decrease in resistance performance of the battery.
  • the average particle diameter of the inorganic particles is preferably in the range of about 0.001 ⁇ m to 10 ⁇ m so as to have a proper porosity with a uniform thickness in the gel polymer electrolyte. If the average particle size is less than 0.001 ⁇ m dispersibility may be lowered, if the average particle diameter is more than 10 ⁇ m not only can increase the thickness of the porous coating layer, but also agglomeration of inorganic particles occurs gel gel electrolyte Exposure to the outside can lower the mechanical strength.
  • the gel polymer electrolyte may have a content of unreacted oligomers of 20% or less relative to the total amount of reactive oligomers at 25 ° C.
  • the content of the unreacted oligomer may be implemented by implementing a gel polymer electrolyte, extracting the gel polymer electrolyte with a solvent (acetone), and then checking the extracted solvent through nuclear magnetic resonance (NMR) measurement.
  • a solvent acetone
  • the electrolyte for a lithium secondary battery according to an embodiment of the present invention may further include an additive for forming an SEI film as needed.
  • SEI film-forming additives usable in the present invention are representative examples thereof, such as vinylene carbonate, vinylethylene carbonate, fluoroethylene carbonate, cyclic sulfite, saturated sultone, unsaturated sultone, acyclic sulfone, etc., alone or in combination of two or more thereof. Can be used.
  • the cyclic sulfites include ethylene sulfite, methyl ethylene sulfite, ethyl ethylene sulfite, 4,5-dimethyl ethylene sulfite, 4,5-diethyl ethylene sulfite, propylene sulfite, 4,5-dimethyl Propylene sulfite, 4,5-diethyl propylene sulfite, 4,6-dimethyl propylene sulfite, 4,6-diethyl propylene sulfite, 1,3-butylene glycol sulfite, and the like. Examples thereof include 1,3-propane sultone and 1,4-butane sultone.
  • unsaturated sultone examples include ethene sultone, 1,3-propene sultone, 1,4-butene sultone, 1-methyl-1,3 -Propene sulfone, and the like, and acyclic sulfones include divinyl sulfone, dimethyl sulfone, diethyl sulfone, methylethyl sulfone, and methyl vinyl sulfone.
  • the additive for forming the SEI film is preferably included 7 wt% or less, specifically 0.01 wt% to 5 wt% based on the total weight of the electrolyte for the lithium secondary battery in order to increase resistance and prevent side reactions due to the use of additives in excess. .
  • the gel polymer electrolyte of the present invention includes a matrix polymer formed by polymerizing the oligomer represented by Chemical Formula 1 in a three-dimensional structure, not only the mechanical properties and the ionic conductivity are improved, but also the oxidation reaction is inhibited during high temperature storage and overcharge. High temperature durability can be ensured.
  • a protective layer made of a polymer on the surface of the positive electrode and the negative electrode, or by using a polymer structure to suppress side reactions through anion stabilization and to increase the adhesion between the electrodes can suppress the generation of gas inside the battery at a high temperature. Therefore, a lithium secondary battery having improved stability at high temperature storage and overcharging may be manufactured.
  • a cathode interposed between the cathode, the anode, the cathode and the anode, and
  • the lithium secondary battery electrolyte may be a liquid electrolyte or a gel polymer electrolyte.
  • the lithium secondary battery of the present invention accommodates an electrode assembly formed by sequentially stacking a separator interposed between a positive electrode, a negative electrode, and a positive electrode and a negative electrode in a secondary battery case or an exterior material. It can be prepared by injecting the electrolyte for a lithium secondary battery of the present invention.
  • the lithium secondary battery electrolyte is a gel polymer electrolyte containing a polymer matrix formed by the polymerization of the oligomer represented by the formula (1)
  • the lithium secondary battery of the present invention selectively between the positive electrode, the negative electrode, and the positive electrode and the negative electrode
  • the electrode assembly formed by sequentially stacking the intervening separator may be accommodated in a secondary battery case or an exterior member, and then injected into the lithium secondary battery electrolyte, followed by curing reaction.
  • the thermal polymerization temperature may be 60 °C to 100 °C, specifically 60 °C to 80 °C.
  • the positive electrode, the negative electrode and the separator may be used all those prepared and used in a conventional manner when manufacturing a lithium secondary battery.
  • the positive electrode may be manufactured by forming a positive electrode mixture layer on a positive electrode current collector.
  • the cathode mixture layer may be formed by coating a cathode active material slurry including a cathode active material, a binder, a conductive material, a solvent, and the like on a cathode current collector, followed by drying and rolling.
  • the positive electrode current collector is not particularly limited as long as it has conductivity without causing chemical changes in the battery.
  • the positive electrode current collector may be formed of stainless steel, aluminum, nickel, titanium, calcined carbon, or carbon on the surface of aluminum or stainless steel. Surface treated with nickel, titanium, silver, or the like may be used.
  • the positive electrode active material is a compound capable of reversible intercalation and deintercalation of lithium, and may specifically include a lithium composite metal oxide containing lithium and one or more metals such as cobalt, manganese, nickel or aluminum. have. More specifically, the lithium composite metal oxide is a lithium-manganese oxide (eg, LiMnO 2 , LiMn 2 O 4, etc.), lithium-cobalt oxide (eg, LiCoO 2, etc.), lithium-nickel oxide (for example, LiNiO 2 and the like), lithium-nickel-manganese-based oxide (for example, LiNi 1-Y Mn Y O 2 (where, 0 ⁇ Y ⁇ 1), LiMn 2-z Ni z O 4 ( here, 0 ⁇ Z ⁇ 2) and the like), lithium-nickel-cobalt oxide (e.g., LiNi 1-Y1 Co Y1 O 2 (here, 0 ⁇ Y1 ⁇ 1) and the like), lithium-manganese-cobal
  • the lithium composite metal oxide may be LiCoO 2 , LiMnO 2 , LiNiO 2 , or lithium nickel manganese cobalt oxide (for example, Li (Ni 1/3 Mn 1/3 Co 1). / 3) O 2, Li ( Ni 0.6 Mn 0.2 Co 0.2) O 2, Li (Ni 0.5 Mn 0.3 Co 0.2 ) O 2 , Li (Ni 0.7 Mn 0.15 Co 0.15 ) O 2, and Li (Ni 0.8 Mn 0.1 Co 0.1 ) O 2 , or the like, or lithium nickel cobalt aluminum oxide (eg, Li (Ni 0.8 Co 0.15 Al 0.05 ) O 2 , and the like.
  • Li ( Ni 0.6 Mn 0.2 Co 0.2) O 2 Li (Ni 0.5 Mn 0.3 Co 0.2 ) O 2 , Li (Ni 0.7 Mn 0.15 Co 0.15 ) O 2
  • the cathode active material may be included in an amount of 80 wt% to 99 wt%, specifically 85 wt% to 95 wt%, based on the total weight of solids in the cathode active material slurry.
  • the content of the positive electrode active material is 80% by weight or less, the energy density is lowered and thus the capacity may be lowered.
  • the binder is a component that assists in bonding the active material and the conductive material and bonding to the current collector, and is generally added in an amount of 1 wt% to 30 wt% based on the total weight of solids in the cathode active material slurry.
  • binders examples include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoro Low ethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluorine rubber, various copolymers, and the like.
  • PVDF polyvinylidene fluoride
  • CMC carboxymethyl cellulose
  • EPDM ethylene-propylene-diene terpolymer
  • EPDM ethylene-propylene-diene terpolymer
  • EPDM ethylene-propylene-diene terpolymer
  • EPDM ethylene-propylene-diene terpolymer
  • EPDM ethylene-propylene-diene terpolymer
  • EPDM ethylene-
  • the conductive material is not particularly limited as long as it has conductivity without causing chemical change in the battery.
  • carbon black acetylene black, ketjen black, channel black, furnace black, lamp black, or thermal black may be used.
  • Carbon powder Graphite powders such as natural graphite, artificial graphite, or graphite with very advanced crystal structure
  • Conductive fibers such as carbon fibers and metal fibers
  • Metal powders such as carbon fluoride powder, aluminum powder and nickel powder
  • Conductive whiskeys such as zinc oxide and potassium titanate
  • Conductive metal oxides such as titanium oxide
  • Conductive materials such as polyphenylene derivatives and the like can be used.
  • the conductive material is typically added in an amount of 1 wt% to 30 wt% based on the total weight of solids in the cathode active material slurry.
  • the conductive material is Chevron Chemical Company, Denka Singapore Private Limited, Gulf Oil Company, etc., Ketjenblack, EC series (Armak Company) Armak Company), Vulcan XC-72 (Cabot Company), and Super P (manufactured by Timcal) can also be used.
  • the solvent may include an organic solvent such as N-methyl-2-pyrrolidone (NMP), and may be used in an amount that becomes a desirable viscosity when including the positive electrode active material and optionally a binder and a conductive material.
  • NMP N-methyl-2-pyrrolidone
  • the concentration of the solids in the positive electrode active material and, optionally, the slurry including the binder and the conductive material may be 10 wt% to 70 wt%, preferably 20 wt% to 60 wt%.
  • the negative electrode may be prepared by forming a negative electrode mixture layer on the negative electrode current collector.
  • the negative electrode mixture layer may be formed by coating a negative electrode active material slurry including a negative electrode active material, a binder, a conductive material, a solvent, and the like on a negative electrode current collector, followed by drying and rolling.
  • the negative electrode current collector generally has a thickness of 3 to 500 ⁇ m.
  • a negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery.
  • copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel Surface-treated with carbon, nickel, titanium, silver, and the like on the surface, aluminum-cadmium alloy and the like can be used.
  • fine concavities and convexities may be formed on the surface to enhance the bonding strength of the negative electrode active material, and may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric.
  • the negative electrode active material may be lithium metal, a carbon material capable of reversibly intercalating / deintercalating lithium ions, a metal or an alloy of these metals and lithium, a metal complex oxide, and may dope and undo lithium. At least one selected from the group consisting of materials, and transition metal oxide transition metal oxides.
  • any carbon-based negative electrode active material generally used in a lithium ion secondary battery may be used without particular limitation.
  • Examples thereof include crystalline carbon, Amorphous carbons or these may be used together.
  • Examples of the crystalline carbon include graphite such as amorphous, plate, flake, spherical or fibrous natural graphite or artificial graphite, and examples of the amorphous carbon include soft carbon (soft carbon) Or hard carbon, mesophase pitch carbide, calcined coke, or the like.
  • the metals or alloys of these metals with lithium include Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al And a metal selected from the group consisting of Sn or an alloy of these metals with lithium may be used.
  • the metal complex oxide may include PbO, PbO 2 , Pb 2 O 3 , Pb 3 O 4 , Sb 2 O 3 , Sb 2 O 4 , Sb 2 O 5 , GeO, GeO 2 , Bi 2 O 3 , Bi 2 O 4 , Bi 2 O 5 , Li x Fe 2 O 3 (0 ⁇ x ⁇ 1), Li x8 WO 2 (0 ⁇ x8 ⁇ 1), and Sn x Me 1- x Me ' y O z (Me: Mn, Fe Me ': Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, halogen; 0 ⁇ x ⁇ 1;1 ⁇ y ⁇ 3; 1 ⁇ z ⁇ 8 Any one selected from the group can be used.
  • Examples of materials capable of doping and undoping lithium include Si, SiO x7 (0 ⁇ x7 ⁇ 2), Si-Y alloys (wherein Y is an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, a transition metal, Is an element selected from the group consisting of rare earth elements and combinations thereof, not Si), Sn, SnO 2 , Sn-Y (Y is an alkali metal, alkaline earth metal, group 13 element, group 14 element, transition metal, rare earth) An element selected from the group consisting of elements and combinations thereof, and not Sn; and at least one of these and SiO 2 may be mixed and used.
  • transition metal oxide examples include lithium-containing titanium composite oxide (LTO), vanadium oxide, lithium vanadium oxide, and the like.
  • the negative active material may be included in an amount of 80 wt% to 99 wt% based on the total weight of solids in the negative electrode active material slurry.
  • the binder is a component that assists the bonding between the conductive material, the active material and the current collector, and is typically added in an amount of 1% by weight to 30% by weight based on the total weight of solids in the negative electrode active material slurry.
  • binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoro Low ethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, fluorine rubber, various copolymers thereof, and the like.
  • PVDF polyvinylidene fluoride
  • CMC carboxymethyl cellulose
  • EPDM ethylene-propylene-diene polymer
  • sulfonated-EPDM styrene-butad
  • the conductive material is a component for further improving the conductivity of the negative electrode active material, and may be added in an amount of 1 wt% to 20 wt% based on the total weight of solids in the negative electrode active material slurry.
  • the conductive material is not particularly limited as long as it has conductivity without causing chemical change in the battery.
  • carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, or thermal black may be used.
  • Carbon powder such as natural graphite, artificial graphite, or graphite with very advanced crystal structure
  • Conductive fibers such as carbon fibers and metal fibers
  • Metal powders such as carbon fluoride powder, aluminum powder and nickel powder
  • Conductive whiskeys such as zinc oxide and potassium titanate
  • Conductive metal oxides such as titanium oxide
  • Conductive materials such as polyphenylene derivatives and the like can be used.
  • the solvent may include an organic solvent such as water or NMP, alcohol, etc., and may be used in an amount that becomes a desirable viscosity when including the negative electrode active material and optionally a binder and a conductive material.
  • concentration of the solids in the slurry including the negative electrode active material and, optionally, the binder and the conductive material may be 50 wt% to 75 wt%, preferably 50 wt% to 65 wt%.
  • the separator serves to block internal short circuits of both electrodes and to impregnate the electrolyte, to prepare a separator composition by mixing a polymer resin, a filler, and a solvent, and then directly coating and drying the separator composition on the electrode.
  • the separator film separated from the support may be formed by lamination on the electrode.
  • the separator is a porous polymer film commonly used, for example, a porous polymer made of a polyolefin-based polymer such as ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer and ethylene / methacrylate copolymer
  • the polymer film may be used alone or in a stack thereof, or a conventional porous nonwoven fabric, for example, a non-woven fabric made of high melting point glass fiber, polyethylene terephthalate fiber, or the like may be used, but is not limited thereto.
  • the pore diameter of the porous separator is generally 0.01 to 50 ⁇ m, porosity may be 5% to 95%.
  • the thickness of the porous separator may generally range from 5 to 300 ⁇ m.
  • the external shape of the lithium secondary battery of the present invention is not particularly limited, but may be cylindrical, square, pouch type, or coin type using a can.
  • a cathode active material LiNi 1/3 Co 1/ 3 Mn 1/3 O 2; NCM
  • a conductive material of carbon black (carbon black) 3% by weight a solvent for polyvinylidene fluoride, 3 weight% of a binder Phosphorus N-methyl-2-pyrrolidone (NMP) was added to prepare a positive electrode active material slurry (50% by weight solid content).
  • the positive electrode active material slurry was applied to a thin film of aluminum (Al), which is a positive electrode current collector having a thickness of 20 ⁇ m, and dried to prepare a positive electrode, followed by a roll press to prepare a positive electrode.
  • Al aluminum
  • Negative active material slurry (65 wt% solids) by adding carbon powder as a negative electrode active material, PVDF as a binder and carbon black as a conductive material at 96 wt%, 3 wt% and 1 wt%, respectively, to NMP as a solvent.
  • the negative electrode active material slurry was applied to a copper (Cu) thin film, which is a negative electrode current collector having a thickness of 10 ⁇ m, and dried to prepare a negative electrode, followed by roll press, to prepare a negative electrode.
  • Cu copper
  • the electrode assembly was prepared by sequentially stacking the separator consisting of the prepared positive electrode, the negative electrode, and three layers of polypropylene / polyethylene / polypropylene (PP / PE / PP), and then storing the assembled electrode assembly in a battery case.
  • the lithium secondary battery was manufactured by pouring the liquid electrolyte.
  • Example 1 In preparing the liquid electrolyte of Example 1, except that the compound of Formula 1a-1 is not included, a liquid electrolyte and a secondary battery including the same were prepared in the same manner as in Example 1 (Table 1 below). Reference).
  • a cathode active material LiNi 1/3 Co 1/ 3 Mn 1/3 O 2; NCM
  • a conductive material of carbon black (carbon black) 3% by weight a solvent for polyvinylidene fluoride, 3 weight% of a binder Phosphorus N-methyl-2-pyrrolidone (NMP) was added to prepare a positive electrode active material slurry (50% by weight solid content).
  • the positive electrode active material slurry was applied to a thin film of aluminum (Al), which is a positive electrode current collector having a thickness of 20 ⁇ m, and dried to prepare a positive electrode, followed by a roll press to prepare a positive electrode.
  • Al aluminum
  • Negative active material slurry (65 wt% solids) by adding carbon powder as a negative electrode active material, PVDF as a binder and carbon black as a conductive material at 96 wt%, 3 wt% and 1 wt%, respectively, to NMP as a solvent.
  • the negative electrode W rutile slurry was applied to a thin copper (Cu) thin film which is a negative electrode current collector having a thickness of 10 ⁇ m, dried to prepare a negative electrode, and then roll-rolled to prepare a negative electrode.
  • the electrode assembly was prepared by sequentially stacking the separator consisting of the prepared positive electrode, the negative electrode, and three layers of polypropylene / polyethylene / polypropylene (PP / PE / PP), and then storing the assembled electrode assembly in a battery case.
  • the gel polymer electrolyte composition was infused and then aged for 2 days. Thereafter, this was cured at 70 ° C. for 5 hours to obtain a lithium secondary battery including a gel polymer electrolyte thermally polymerized.
  • Example 5 In preparing the gel polymer electrolyte composition of Example 5, the same procedure as in Example 5 was performed except that 0.3g of the oligomer represented by Chemical Formula 1a-1 and 0.03g of a polymerization initiator were used in 98.67g of the non-aqueous organic solvent. By the method, a gel polymer electrolyte composition and a lithium secondary battery using the same were prepared (see Table 1 below).
  • the amount of the organic solvent is 83.5 g
  • the gel polymer electrolyte is the same as in Example 5, except that 10 g of the inorganic particles (TiO 2 ) is further included.
  • the composition and a lithium secondary battery using the same were prepared (see Table 1 below).
  • Example 5 In the preparation of the gel polymer electrolyte composition of Example 5, the composition for gel polymer electrolyte in the same manner as in Example 5, except that the compound of the formula (2) instead of the oligomer of Formula 1a-1 as an oligomer And a lithium secondary battery using the same (see Table 1 below).
  • the lithium secondary battery comprising the liquid electrolytes prepared in Examples 1 to 4 and the lithium secondary battery comprising the liquid electrolytes prepared in Comparative Examples 1 and 2 were fully charged at 0.33C / 4.15V constant current-constant voltage, respectively, and the SOC 50 Initial charge and discharge were performed by discharging at 5C for 10 seconds. After initial charging and discharging, each was charged to 4.15V, and stored at 80 ° C. for 10 weeks (SOC; 100 of state), and then the thickness increase rate (%) and the resistance increase rate (%) were measured.
  • the thickness increase rate (%) and the resistance increase rate (%) are shown in Table 2 below.
  • the thickness increase rate (%) and the resistance increase rate (%) of the battery were calculated using the following Equations 1 and 2.
  • Battery thickness increase rate (%) [(final thickness-initial thickness) / initial thickness] ⁇ 100 (%)
  • the thickness increase rate at 80 ° C. for the lithium secondary battery including the gel polymer electrolytes prepared in Examples 5 to 10 and the lithium secondary battery including the gel polymer electrolytes prepared in Comparative Example 3 ( %) And resistance increase rate (%) were measured.
  • the thickness increase rate (%) and the resistance increase rate (%) are shown in Table 2 below.
  • Comparative Example 1 provided with a liquid electrolyte not containing oligomer And it can be seen that the thickness increase rate (%) after 10 weeks at 80 °C compared to the lithium secondary battery of 2 is significantly lower.
  • the lithium secondary batteries of Examples 1 to 4 having the liquid electrolyte containing the oligomer represented by the formula (1a-1) of the present invention the lithium of Comparative Examples 1 and 2 provided with the liquid electrolyte containing no oligomer It can be seen that the resistance increase rate (%) was significantly reduced after 10 weeks at 80 ° C. compared with the secondary battery.
  • the gel polymer electrolyte including the polymer derived from the compound of the formula (2) is provided.
  • the resistance increase rate (%) was significantly reduced after 10 weeks at 80 ° C.
  • the amount of CO gas generated in the lithium secondary battery of Example 1 having the liquid electrolyte including the oligomer of the present invention was about 100 ⁇ l, and the amount of CO 2 gas was about 200 ⁇ l or less. have.
  • the generated CO gas content is about 700 ⁇ l
  • the CO 2 gas content is about 500 ⁇ l
  • the secondary battery of Example 1 In contrast, it can be seen that about 6 times more gas is generated.
  • liquid electrolyte including the oligomer according to the embodiment of the present invention showed excellent oxidative stability and significantly reduced the amount of gas generated inside the secondary battery.
  • the CO gas content generated in the lithium secondary batteries of Examples 5 and 6 including the gel polymer electrolyte including the oligomer-derived polymer according to the embodiment of the present invention is about 500 ⁇ l, and CO 2 It can be seen that the gas content is about 300 ⁇ l or less.
  • the generated CO gas content is about 1000 ⁇ l
  • CO 2 gas content is about 2000 ⁇ l
  • the CO gas was reduced by 50% or more, and the CO 2 gas was reduced by about 70% to 80% or more compared with the secondary battery of Comparative Example 3.
  • the gel electrolyte including the oligomer according to the embodiment of the present invention shows excellent oxidative stability, and the amount of gas generated in the secondary battery is significantly reduced.
  • the gel polymer electrolyte of Example 5 including the polymer derived from the oligomer represented by Chemical Formula 1 has excellent stability against oxidation even in a high voltage region of 4.4 V or higher.
  • Working electrode Graphite (brand name: AGM1 100) Counter electrode Li metal Reference electrode Li metal Voltage range OV ⁇ 3V Scan rate 1 mV / S
  • the lithium secondary battery with the gel polymer electrolyte prepared in Example 5 and the lithium secondary battery with the gel polymer electrolyte prepared in Comparative Example 3 were charged to 25V at 0.5C constant current at 25 ° C., respectively. Charging was terminated when the battery was charged at a constant voltage of 4.2V and the charging current reached 0.275 mA. Thereafter, the battery was discharged for 10 minutes and then discharged until it became 3.0V at 0.5C constant current. After 700 cycles of charging and discharging, the battery capacity was measured and shown in FIG. 5.
  • the lithium secondary battery of Example 5 had almost no change in capacity retention even after 700 cycles, and showed a capacity retention of 93% or more even at the 700th cycle.
  • the lithium secondary battery of Comparative Example 3 exhibited a capacity retention rate similar to that of the secondary battery of Example 5 of the present invention until the initial 200 cycles, but decreased significantly from about 250 cycles, to about 88% in 700 cycles. It showed a sharp decrease.
  • the lithium secondary battery of Example 5 of the present invention has improved cycle life characteristics at room temperature compared to the lithium secondary battery of Comparative Example 3.
  • the lithium secondary battery of Example 5 having the gel polymer electrolyte containing the oligomer of the present invention has a relatively low voltage drop compared to the lithium secondary battery of Comparative Example 3.
  • the lithium secondary battery of Example 5 having the gel polymer electrolyte including the oligomer of the present invention has improved low temperature characteristics compared to the secondary battery of Comparative Example 3.
  • the negative electrode was subjected to differential scanning calorimetry (DSC). : differential scanning calorimeter). Measurement conditions were measured at intervals of 10 ° C / min from 25 ° C to 400 ° C. The results are shown in FIG.
  • a solid polymer electrolyte (SEI) film is formed on the surface of the negative electrode during initial charging. If the membrane is not decomposed at high temperature, side reaction between the negative electrode and the electrolyte is prevented, thereby improving battery stability.
  • SEI solid polymer electrolyte
  • the secondary battery of Example 5 using the gel polymer electrolyte containing the oligomer according to the embodiment of the present invention it can be seen that the decomposition temperature of the SEI film on the surface of the negative electrode is about 60 °C higher than in Comparative Example 1. Therefore, it can be seen that the lithium secondary battery of Example 5 of the present invention is more excellent in passion stability than the lithium secondary battery of Comparative Example 3.

Abstract

The present invention relates to an electrolyte for a lithium secondary battery and a lithium secondary battery comprising the same and, more particularly, to an electrolyte for a lithium secondary battery comprising a lithium salt, an organic solvent, and an oligomer represented by formula 1 disclosed in the present specification, and a lithium secondary battery comprising the same, wherein the electrolyte suppresses reactivity with lithium metal to improve overall performance.

Description

리튬 이차전지용 전해질 및 이를 포함하는 리튬 이차전지Electrolyte for lithium secondary battery and lithium secondary battery comprising same
관련 출원(들)과의 상호 인용Cross Citation with Related Application (s)
본 출원은 2016년 12월 08일자 한국 특허 출원 제10-2016-0166991호 및 제10-2016-0166992호와, 2017년 12월 08일자 한국 특허 출원 제10-2017-0168433호에 기초한 우선권의 이익을 주장하며, 해당 한국 특허 출원의 문헌에 개시된 모든 내용은 본 명세서의 일부로서 포함된다. This application claims the benefit of priority based on Korean Patent Application Nos. 10-2016-0166991 and 10-2016-0166992 on December 08, 2016, and Korean Patent Application No. 10-2017-0168433 on December 08, 2017. All contents disclosed in the literature of the relevant Korean patent application are incorporated as part of this specification.
기술분야Technical Field
본 발명은 고온 내구성이 향상된 리튬 이차전지용 전해질 및 이를 포함하는 리튬 이차전지에 관한 것이다.The present invention relates to an electrolyte for a lithium secondary battery having improved high temperature durability and a lithium secondary battery including the same.
최근 휴대폰, 캠코더 및 노트북 PC, 나아가서 전기자동차에 대한 기술 개발과 수요가 증가함에 따라, 에너지 저장 기술에 대한 관심이 갈수록 높아지고 있다. Recently, as technology development and demand for mobile phones, camcorders and notebook PCs, and even electric vehicles increase, interest in energy storage technology is increasing.
특히, 에너지 저장 기술 분야 중에서도 높은 에너지 밀도와 전압을 가지며, 충방전이 가능한 리튬 이차전지에 대한 관심이 대두되고 있다.In particular, interest in lithium secondary batteries having high energy density and voltage, and capable of charging and discharging is emerging among energy storage technologies.
상기 리튬 이차전지는 일반적으로 리튬 이온을 삽입/방출할 수 있는 전극활물질을 포함하는 양극과 음극, 및 리튬 이온의 전달 매질인 전해질로 이루어져 있다. The lithium secondary battery generally includes a positive electrode and a negative electrode including an electrode active material capable of inserting / releasing lithium ions, and an electrolyte which is a transfer medium of lithium ions.
상기 전해질로는 전해질염이 용해된 비수성 유기용매를 포함하는 액체 전해질 또는 상기 액체 전해질에 매트릭스 폴리머를 더 포함하는 겔 폴리머 전해질이 적용되고 있다.As the electrolyte, a liquid electrolyte containing a non-aqueous organic solvent in which an electrolyte salt is dissolved or a gel polymer electrolyte further comprising a matrix polymer in the liquid electrolyte is used.
한편, 리튬 이차전지의 충방전 시에 상기 전해질이 분해되거나, 또는 전극과 전해질의 부반응에 의해 이차전지 내부에서 가스가 발생할 수 있으며, 이러한 가스 발생은 고온 저장시에 더욱 증가한다.On the other hand, the electrolyte is decomposed during charging and discharging of the lithium secondary battery, or gas may be generated inside the secondary battery by side reaction between the electrode and the electrolyte, and such gas generation is further increased during high temperature storage.
이와 같이 지속적으로 발생된 가스는 전지의 내압 증가를 유발시켜 전지의 두께를 팽창시키는 등 전지의 변형을 초래할 뿐만 아니라, 전지 내 전극면에서 밀착성이 국부적으로 달라져서 전극 반응이 전체 전극면에서 동일하게 일어나지 못하는 문제를 야기할 수 있다. This continuously generated gas not only causes deformation of the battery, such as causing an increase in the internal pressure of the battery, thereby expanding the thickness of the battery, but also locally changing the adhesion on the electrode surface of the battery, so that the electrode reaction does not occur identically on the entire electrode surface. It can cause problems.
이에, 리튬 이차전지의 안정성 향상과 고출력 특성 향상을 위하여, 고온 저장 및 과충전 시 가스 발생 및 발열 반응 등이 억제되어 안정성이 향상된 리튬 이차전지에 대한 개발이 필요한 실정이다.Thus, in order to improve the stability and high output characteristics of the lithium secondary battery, it is necessary to develop a lithium secondary battery having improved stability by suppressing gas generation and exothermic reaction during high temperature storage and overcharging.
선행기술문헌Prior art literature
대한민국 특허공개공보 제2013-0058403호Republic of Korea Patent Publication No. 2013-0058403
대한민국 특허공개공보 제2009-0015859호Republic of Korea Patent Publication No. 2009-0015859
본 발명은 이와 같은 문제를 해결하기 위하여 안출된 것으로,The present invention has been made to solve such a problem,
본 발명의 제1 기술적 과제는 고온 저장 및 과충전 시에 산화 반응이 억제되어 고온 내구성이 향상된 리튬 이차전지용 전해질을 제공하는 것을 목적으로 한다. It is an object of the present invention to provide an electrolyte for a lithium secondary battery in which an oxidation reaction is suppressed during high temperature storage and overcharge, thereby improving the high temperature durability.
또한, 본 발명의 제2 기술적 과제는 상기 리튬 이차전지용 전해질을 포함함으로써, 고온 저장 및 과충전 시에 안정성이 향상된 리튬 이차전지를 제공하는 것을 목적으로 한다. In addition, a second technical problem of the present invention is to provide a lithium secondary battery having improved stability at high temperature storage and overcharge by including the electrolyte for a lithium secondary battery.
상기 과제를 해결하기 위하여, 본 발명의 일 실시예에서는In order to solve the above problems, in one embodiment of the present invention
리튬염; Lithium salts;
유기용매; 및Organic solvents; And
하기 화학식 1로 표시되는 올리고머를 포함하는 리튬 이차전지용 전해질을 제공한다.To provide a lithium secondary battery electrolyte comprising an oligomer represented by the formula (1).
[화학식 1][Formula 1]
Figure PCTKR2017014432-appb-I000001
Figure PCTKR2017014432-appb-I000001
상기 화학식 1에서,In Chemical Formula 1,
R은 지방족 탄화수소기 또는 방향족 탄화수소기이며,R is an aliphatic hydrocarbon group or an aromatic hydrocarbon group,
R1 내지 R3는 각각 독립적으로 불소로 치환 또는 비치환된 탄소수 1 내지 5의 알킬렌기이고, R 1 to R 3 are each independently an alkylene group having 1 to 5 carbon atoms unsubstituted or substituted with fluorine,
R4는 탄소수 1 내지 4의 알킬렌기이며,R 4 is an alkylene group having 1 to 4 carbon atoms,
R'는 수소 또는 탄소수 1 내지 3의 알킬기이고,R 'is hydrogen or an alkyl group having 1 to 3 carbon atoms,
a는 1 내지 3이며,a is 1 to 3,
n은 반복단위 수이고,n is the number of repeat units,
n은 1 내지 75 중 어느 하나의 정수이다.n is an integer of any one of 1 to 75.
이때, 상기 화학식 1로 표시되는 올리고머에서, At this time, in the oligomer represented by Formula 1,
상기 지방족 탄화수소기는 치환 또는 비치환된 탄소수 4 내지 20의 사이클로알킬렌기; 이소시아네이트기(NCO)를 함유하는 치환 또는 비치환된 탄소수 4 내지 20의 사이클로알킬렌기; 치환 또는 비치환된 탄소수 4 내지 20의 사이클로알케닐렌기; 및 치환 또는 비치환된 탄소수 2 내지 20의 헤테로사이클로알킬렌기로 이루어진 군으로부터 선택된 적어도 하나 이상의 지환족 탄화수소기, 또는 치환 또는 비치환된 탄소수 1 내지 20의 알킬렌기; 이소시아네이트기(NCO)를 함유하는 치환 또는 비치환된 탄소수 1 내지 20의 알킬렌기; 치환 또는 비치환된 탄소수 1 내지 20의 알콕실렌기; 치환 또는 비치환된 탄소수 2 내지 20의 알케닐렌기; 및 치환 또는 비치환된 탄소수 2 내지 20의 알키닐렌기로 이루어진 군으로부터 선택된 선형 탄화수소기이고, The aliphatic hydrocarbon group may be substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms; A substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms containing an isocyanate group (NCO); A substituted or unsubstituted cycloalkenylene group having 4 to 20 carbon atoms; And at least one alicyclic hydrocarbon group selected from the group consisting of a substituted or unsubstituted heterocycloalkylene group having 2 to 20 carbon atoms, or a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms; Substituted or unsubstituted C1-C20 alkylene group containing an isocyanate group (NCO); A substituted or unsubstituted alkoxylene group having 1 to 20 carbon atoms; A substituted or unsubstituted alkenylene group having 2 to 20 carbon atoms; And a linear hydrocarbon group selected from the group consisting of substituted or unsubstituted alkynylene group having 2 to 20 carbon atoms,
상기 방향족 탄화수소기는 치환 또는 비치환된 탄소수 6 내지 20의 아릴렌기; 또는 치환 또는 비치환된 탄소수 2 내지 20의 헤테로아릴렌기일 수 있다.The aromatic hydrocarbon group is substituted or unsubstituted arylene group having 6 to 20 carbon atoms; Or a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms.
구체적으로, 상기 화학식 1로 표시되는 올리고머는 하기 화학식 1a로 표시되는 올리고머일 수 있다.Specifically, the oligomer represented by Formula 1 may be an oligomer represented by Formula 1a.
[화학식 1a][Formula 1a]
Figure PCTKR2017014432-appb-I000002
Figure PCTKR2017014432-appb-I000002
상기 화학식 1a에서,In Chemical Formula 1a,
R은 지방족 탄화수소기 또는 방향족 탄화수소기이고,R is an aliphatic hydrocarbon group or an aromatic hydrocarbon group,
R1은 불소로 치환 또는 비치환된 탄소수 1 내지 5의 알킬렌기이고, R 1 is an alkylene group having 1 to 5 carbon atoms substituted or unsubstituted with fluorine,
n1은 반복단위 수이며,n1 is the number of repeat units,
n1은 1 내지 75 중 어느 하나의 정수이다.n1 is an integer of any one of 1-75.
보다 구체적으로, 상기 화학식 1a로 표시되는 올리고머는 하기 화학식 1a-1로 표시되는 올리고머일 수 있다.More specifically, the oligomer represented by Formula 1a may be an oligomer represented by Formula 1a-1.
[화학식 1a-1][Formula 1a-1]
Figure PCTKR2017014432-appb-I000003
Figure PCTKR2017014432-appb-I000003
상기 화학식 1a-1에서, In Chemical Formula 1a-1,
n2는 반복단위 수이며,n2 is the number of repeat units,
n2는 20 내지 75 중 어느 하나의 정수다.n2 is an integer of any one of 20-75.
상기 화학식 1로 표시되는 올리고머는 리튬 이차전지용 전해질 전체 중량을 기준으로 0.5 중량% 내지 20 중량%, 구체적으로 0.5 중량% 내지 15 중량%로 포함될 수 있다.The oligomer represented by Chemical Formula 1 may be included in an amount of 0.5 wt% to 20 wt%, specifically 0.5 wt% to 15 wt%, based on the total weight of the lithium secondary battery electrolyte.
이때, 상기 화학식 1로 표시되는 올리고머를 포함하는 경우, 상기 리튬 이차전지용 전해질은 액체 전해질일 수 있다.In this case, when the oligomer represented by Chemical Formula 1 is included, the lithium secondary battery electrolyte may be a liquid electrolyte.
또한, 상기 화학식 1로 표시되는 올리고머 유래의 폴리머를 포함하는 경우, 상기 리튬 이차전지용 전해질은 겔 폴리머 전해질일 수 있다.In addition, when the polymer derived from the oligomer represented by the formula (1), the lithium secondary battery electrolyte may be a gel polymer electrolyte.
상기 화학식 1로 표시되는 올리고머 유래의 폴리머는 중합개시제 존재하에서 화학식 1로 표시되는 올리고머가 중합하여 3차원 구조로 형성된 매트릭스 폴리머일 수 있다.The polymer derived from the oligomer represented by Formula 1 may be a matrix polymer formed in a three-dimensional structure by polymerization of the oligomer represented by Formula 1 in the presence of a polymerization initiator.
상기 겔 폴리머 전해질은 무기물 입자를 추가로 포함할 수 있다.The gel polymer electrolyte may further include inorganic particles.
이러한 무기물 입자는 BaTiO3, BaTiO3 , Pb(ZrxTi1-x)O3 (0≤x≤1) (PZT), Pb1 -bLabZr1-cTicO3 (PLZT, 여기서, 0<b<1, 0<c<1임), Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT), 하프니아(HfO2), SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiC 및 이들의 혼합체로부터 이루어진 군으로부터 선택된 단일물 또는 2종 이상의 혼합물을 포함할 수 있다.Such inorganic particles include BaTiO 3 , BaTiO 3 , Pb (Zr x Ti 1-x ) O 3 (0 ≦ x ≦ 1) (PZT), Pb 1- b La b Zr 1-c Ti c O 3 (PLZT, where , 0 <b <1, 0 <c <1), Pb (Mg 1/3 Nb 2/3 ) O 3 -PbTiO 3 (PMN-PT), Hafnia (HfO 2 ), SrTiO 3 , SnO 2 , It may include a single or a mixture of two or more selected from the group consisting of CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 , Al 2 O 3 , TiO 2 , SiC and mixtures thereof.
상기 무기물 입자는 리튬 이차전지용 전해질 전체 중량을 기준으로 10 중량% 내지 25 중량%로 포함될 수 있다.The inorganic particles may be included in 10% by weight to 25% by weight based on the total weight of the electrolyte for a lithium secondary battery.
또한, 본 발명의 일 실시예에서는In addition, in one embodiment of the present invention
음극, 양극, 상기 음극 및 양극 사이에 개재된 분리막, 및A cathode interposed between the cathode, the anode, the cathode and the anode, and
본 발명의 리튬 이차전지용 전해질을 포함하는 리튬 이차전지를 제공할 수 있다.It is possible to provide a lithium secondary battery comprising the electrolyte for a lithium secondary battery of the present invention.
이때, 상기 리튬 이차전지용 전해질은 액체 전해질 또는 겔 폴리머 전해질일 수 있다.In this case, the lithium secondary battery electrolyte may be a liquid electrolyte or a gel polymer electrolyte.
이상에서 설명한 바와 같이, 본 발명에 따르면 친수성 및 소수성 관능기를 가지는 올리고머를 포함함으로써, 전극 표면과의 표면장력을 낮춰 젖음성을 향상시킬 수 있을 뿐만 아니라, 초기 충전시 전극 표면에 안정한 이온전도성 피막을 형성함으로써 고온 저장 및 과충전 시에 전해질 부반응 및 산화 반응을 방지하여 고온 내구성이 향상된 리튬 이차전지용 전해질을 제공할 수 있다. 나아가, 본 발명은 이러한 리튬 이차전지용 전해질을 구비함으로써 고온 저장 및 과충전 시 발열 반응이 억제되어 안정성 등의 제반 성능이 향상된 리튬 이차전지를 제조할 수 있다.As described above, according to the present invention, by including oligomers having hydrophilic and hydrophobic functional groups, the surface tension with the electrode surface can be lowered to improve wettability, and a stable ion conductive film is formed on the electrode surface during initial charging. As a result, it is possible to provide a lithium secondary battery electrolyte having improved high temperature durability by preventing electrolyte side reactions and oxidation reactions during high temperature storage and overcharge. Furthermore, the present invention provides a lithium secondary battery having such a lithium secondary battery electrolyte, thereby suppressing an exothermic reaction during high temperature storage and overcharging, thereby improving a lithium secondary battery having improved overall performance such as stability.
본 명세서에 첨부되는 다음의 도면은 본 발명의 바람직한 실시예를 예시하는 것이며, 전술한 발명의 내용과 함께 본 발명의 기술 사상을 더욱 이해시키는 역할을 하는 것이므로, 본 발명은 그러한 도면에 기재된 사항에만 한정되어 해석되어서는 아니다.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 idea of the present invention, the present invention is limited to the matters described in such drawings. It is not to be construed as limited.
도 1은 본 발명의 실험예 2에 따른 실시예 1 및 비교예 1의 리튬 이차전지로부터 발생된 가스 함량을 나타낸 그래프이다.1 is a graph showing the gas content generated from the lithium secondary battery of Example 1 and Comparative Example 1 according to Experimental Example 2 of the present invention.
도 2는 본 발명의 실험예 3에 따른 실시예 5 및 6과 비교예 3의 리튬 이차전지로부터 발생된 가스 함량을 나타낸 그래프이다.2 is a graph showing the gas content generated from the lithium secondary battery of Examples 5 and 6 and Comparative Example 3 according to Experimental Example 3 of the present invention.
도 3은 본 발명의 실험예 4에 따른 실시예 5의 겔 폴리머 전해질과 비교예 1의 액체 전해질에 대한 산화 안정성 평가 결과를 나타낸 그래프이다.3 is a graph showing the results of evaluation of the oxidation stability of the gel polymer electrolyte of Example 5 and the liquid electrolyte of Comparative Example 1 according to Experimental Example 4 of the present invention.
도 4는 본 발명의 실험예 4에 따른 실시예 6의 겔 폴리머 전해질과 비교예 2의 액체 전해질에 대한 환원 안정성 평가 결과를 나타낸 그래프이다.4 is a graph showing the results of evaluating the reduction stability of the gel polymer electrolyte of Example 6 and the liquid electrolyte of Comparative Example 2 according to Experimental Example 4 of the present invention.
도 5는 본 발명의 실험예 5에 따른 실시예 5 및 비교예 3의 리튬 이차전지의 상온(25℃)에서의 성능 평가 결과를 나타낸 그래프이다.5 is a graph showing the results of the performance evaluation at room temperature (25 ℃) of the lithium secondary battery of Example 5 and Comparative Example 3 according to Experimental Example 5 of the present invention.
도 6은 본 발명의 실험예 6에 따른 실시예 5 및 비교예 3의 리튬 이차전지의 저온(-10℃)에서의 성능 평가 결과를 나타낸 그래프이다.FIG. 6 is a graph illustrating performance evaluation results at low temperatures (−10 ° C.) of lithium secondary batteries of Example 5 and Comparative Example 3 according to Experimental Example 6 of the present invention. FIG.
도 7은 본 발명의 실험예 7에 따른 실시예 5 및 비교예 3의 리튬 이차전지의 열적 안정성 평가 결과를 나타낸 그래프이다.7 is a graph illustrating thermal stability evaluation results of the lithium secondary battery of Example 5 and Comparative Example 3 according to Experimental Example 7 of the present invention.
이하, 본 발명을 더욱 상세하게 설명한다. Hereinafter, the present invention will be described in more detail.
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.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.
구체적으로, 본 발명의 일 실시예에서는Specifically, in one embodiment of the present invention
리튬염; Lithium salts;
유기용매; 및Organic solvents; And
하기 화학식 1로 표시되는 올리고머를 포함하는 리튬 이차전지용 전해질을 제공한다.To provide a lithium secondary battery electrolyte comprising an oligomer represented by the formula (1).
[화학식 1][Formula 1]
Figure PCTKR2017014432-appb-I000004
Figure PCTKR2017014432-appb-I000004
상기 화학식 1에서,In Chemical Formula 1,
R은 지방족 탄화수소기 또는 방향족 탄화수소기이며,R is an aliphatic hydrocarbon group or an aromatic hydrocarbon group,
R1 내지 R3는 각각 독립적으로 불소로 치환 또는 비치환된 탄소수 1 내지 5의 알킬렌기이고, R 1 to R 3 are each independently an alkylene group having 1 to 5 carbon atoms unsubstituted or substituted with fluorine,
R4는 탄소수 1 내지 4의 알킬렌기이며,R 4 is an alkylene group having 1 to 4 carbon atoms,
R'는 수소 또는 탄소수 1 내지 3의 알킬기이고,R 'is hydrogen or an alkyl group having 1 to 3 carbon atoms,
a는 1 내지 3이며,a is 1 to 3,
n은 반복단위 수이고,n is the number of repeat units,
n은 1 내지 75 중 어느 하나의 정수이다.n is an integer of any one of 1 to 75.
먼저, 본 발명의 일 실시예에 따른 리튬 이차전지용 전해질에 있어서, 상기 리튬염은 리튬 이차전지용 전해질에 통상적으로 사용되는 것들이 제한 없이 사용될 수 있으며, 예를 들어 상기 리튬염의 양이온으로 Li+를 포함하고, 음이온으로는 F-, Cl-, Br-, I-, NO3 -, N(CN)2 -, BF4 -, ClO4 -, AlO4 -, AlCl4 -, PF6 -, SbF6 -, AsF6 -, BF2C2O4 -, BC4O8 -, PF4C2O4 -, PF2C4O8 -, (CF3)2PF4 -, (CF3)3PF3 -, (CF3)4PF2 -, (CF3)5PF-, (CF3)6P-, CF3SO3 -, C4F9SO3 -, 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 군으로부터 선택된 적어도 어느 하나를 들 수 있다. 구체적으로, 상기 리튬염은 LiCl, LiBr, LiI, LiClO4, LiBF4, LiB10Cl10, LiPF6, LiCF3SO3, LiCH3CO2, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, LiAlO4, 및 LiCH3SO3으로 이루어진 군으로부터 선택된 단일물 또는 2종 이상의 혼합물을 포함할 수 있고, 이들 외에도 리튬 이차전지의 전해질에 통상적으로 사용되는 LiBETI (lithium bisperfluoroethanesulfonimide, LiN(SO2C2F5)2), LiFSI (lithium fluorosulfonyl imide, LiN(SO2F)2), 및 LiTFSI (lithium (bis)trifluoromethanesulfonimide, LiN(SO2CF3)2)로 나타내는 리튬 이미드염과 같은 리튬염을 제한 없이 사용할 수 있다. 구체적으로 상기 리튬염은 LiPF6, LiBF4, LiCH3CO2, LiCF3CO2, LiCH3SO3, LiFSI, LiTFSI 및 LiN(C2F5SO2)2으로 이루어진 군으로부터 선택된 단일물 또는 2종 이상의 혼합물을 포함할 수 있다. First, in the lithium secondary battery electrolyte according to an embodiment of the present invention, the lithium salt may be used without limitation those conventionally used in the electrolyte for lithium secondary batteries, for example, includes Li + as the cation of the lithium salt anion include F -, Cl -, Br - , I -, NO 3 -, N (CN) 2 -, BF 4 -, ClO 4 -, AlO 4 -, AlCl 4 -, PF 6 -, SbF 6 - , AsF 6 -, BF 2 C 2 O 4 -, BC 4 O 8 -, PF 4 C 2 O 4 -, PF 2 C 4 O 8 -, (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 -, C 4 F 9 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 - , selected from the group consisting of At least one can be mentioned. Specifically, the lithium salt is LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiPF 6 , LiCF 3 SO 3 , LiCH 3 CO 2 , LiCF 3 CO 2 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , LiAlO 4 , and LiCH 3 SO 3 It may include a single or a mixture of two or more selected from the group consisting of, in addition to these LiBTI (lithium bisperfluoroethanesulfonimide, LiN (SO 2 C 2 F) commonly used in the electrolyte of the lithium secondary battery 5 ) without limitation lithium salts such as lithium imide salts represented by 2 ), LiFSI (lithium fluorosulfonyl imide, LiN (SO 2 F) 2 ), and LiTFSI (lithium (bis) trifluoromethanesulfonimide, LiN (SO 2 CF 3 ) 2 ) Can be used. Specifically, the lithium salt is a single or two selected from the group consisting of LiPF 6 , LiBF 4 , LiCH 3 CO 2 , LiCF 3 CO 2 , LiCH 3 SO 3 , LiFSI, LiTFSI and LiN (C 2 F 5 SO 2 ) 2 It may contain a mixture of the above.
상기 리튬염은 통상적으로 사용 가능한 범위 내에서 적절히 변경할 수 있으나, 구체적으로 리튬 이차전지용 전해질 내에 0.8 M 내지 3M, 구체적으로 1.0M 내지 2.5M로 포함될 수 있다. 만약, 상기 리튬염의 농도가 3M을 초과하는 경우 전해질의 점도가 증가하여 리튬 이온 이동 효과가 저하될 수 있다.The lithium salt may be appropriately changed within a range generally available, and specifically, may be included in the electrolyte for lithium secondary batteries at 0.8 M to 3M, specifically 1.0M to 2.5M. If the concentration of the lithium salt is greater than 3M, the viscosity of the electrolyte may be increased to reduce the lithium ion migration effect.
또한, 본 발명의 일 실시예에 따른 리튬 이차전지용 전해질에 있어서, 상기 유기용매는 이차전지의 충방전 과정에서 산화 반응 등에 의한 분해가 최소화될 수 있고, 첨가제와 함께 목적하는 특성을 발휘할 수 있는 것이라면 제한이 없다. 예를 들면 상기 유기용매는 에테르계 용매, 에스테르계 용매, 또는 아미드계 용매 등을 각각 단독으로 또는 2종 이상 혼합하여 사용할 수 있다. In addition, in the electrolyte for a lithium secondary battery according to an embodiment of the present invention, if the organic solvent can minimize the decomposition by the oxidation reaction, etc. in the charge and discharge process of the secondary battery, and if it can exhibit the desired characteristics with additives no limits. For example, the organic solvent may be used alone or in combination of two or more of an ether solvent, an ester solvent, an amide solvent, and the like.
상기 유기용매 중 에테르계 용매로는 디메틸에테르, 디에틸에테르, 디프로필 에테르, 메틸에틸에테르, 메틸프로필 에테르 및 에틸프로필 에테르로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물을 사용할 수 있으나, 이에 한정되는 것은 아니다.As the ether solvent 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.
또한, 상기 에스테르계 용매는 환형 카보네이트 화합물, 선형 카보네이트 화합물, 선형 에스테르 화합물, 및 환형 에스테르 화합물로 이루어진 군으로부터 선택된 적어도 하나 이상의 화합물을 포함할 수 있다. In addition, the ester solvent may include at least one compound selected from the group consisting of a cyclic carbonate compound, a linear carbonate compound, a linear ester compound, and a cyclic ester compound.
이중 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-펜틸렌카보네이트, 2,3-펜틸렌 카보네이트, 비닐렌 카보네이트 및 플루오로에틸렌 카보네이트 (FEC)으로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물이 있다.Specific examples of the cyclic carbonate compound include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, and 1,2-pentylene carbonate. , 2,3-pentylene carbonate, vinylene carbonate and fluoroethylene carbonate (FEC), or any one or a mixture of two or more thereof.
또한, 상기 선형 카보네이트 화합물의 구체적인 예로는 디메틸 카보네이트(dimethyl carbonate, DMC), 디에틸 카보네이트(diethyl carbonate, DEC), 디프로필 카보네이트, 에틸메틸 카보네이트(EMC), 메틸프로필 카보네이트 및 에틸프로필 카보네이트로 이루어진 군으로부터 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 compound include dimethyl carbonate (dimethyl carbonate, DMC), diethyl carbonate (diethyl carbonate, DEC), dipropyl carbonate, ethyl methyl carbonate (EMC), methylpropyl carbonate and ethylpropyl carbonate Any one selected from, or a mixture of two or more thereof may be representatively used, but is not limited thereto.
상기 선형 에스테르 화합물은 그 구체적인 예로 메틸 아세테이트, 에틸 아세테이트, 프로필 아세테이트, 메틸 프로피오네이트, 에틸 프로피오네이트, 프로필 프로피오네이트, 및 부틸 프로피오네이트로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물 등이 대표적으로 사용될 수 있으나, 이에 한정되는 것은 아니다.The linear ester compound is any one selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, and butyl propionate. The above mixture and the like can be used representatively, but is not limited thereto.
상기 환형 에스테르 화합물은 그 구체적인 예로 γ-부티로락톤, γ-발레로락톤, γ-카프로락톤, σ-발레로락톤, ε-카프로락톤과 같은 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물을 사용할 수 있으나, 이에 한정되는 것은 아니다.The cyclic ester compound is any one selected from the group consisting of γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone, ε-caprolactone, or two or more thereof Mixtures may be used, but are not limited thereto.
상기 에스테르계 용매 중에서 환형 카보네이트계 화합물은 고점도의 유기용매로서 유전율이 높아 전해질 내의 리튬염을 잘 해리시키므로 바람직하게 사용될 수 있으며, 이러한 환형 카보네이트계 화합물에 디메틸 카보네이트 및 디에틸 카보네이트와 같은 저점도, 저유전율 선형 카보네이트계 화합물 및 선형 에스테르계 화합물을 적당한 비율로 혼합하여 사용하면 높은 전기 전도율을 갖는 전해질을 만들 수 있어 더욱 바람직하게 사용될 수 있다.In the ester solvent, the cyclic carbonate-based compound is a high viscosity organic solvent and has a high dielectric constant, and thus may be preferably used because it dissociates lithium salts in the electrolyte. The cyclic carbonate-based compound has low viscosity and low viscosity such as dimethyl carbonate and diethyl carbonate When the dielectric constant linear carbonate compound and the linear ester compound are mixed and used in an appropriate ratio, an electrolyte having a high electrical conductivity can be made, which can be used more preferably.
또한, 본 발명의 일 실시예에 따른 리튬 이차전지용 전해질은 상기 화학식 1로 표시되는 올리고머를 포함할 수 있다.In addition, the lithium secondary battery electrolyte according to an embodiment of the present invention may include an oligomer represented by the formula (1).
이러한 화학식 1로 표시되는 올리고머는 이차전지 내에서 양극 또는 분리막(SRS층)과 음극 또는 분리막 원단과 균형적인 친화성을 나타내어 전기화학적으로 안정하기 때문에 리튬 이차전지 성능 향상에 큰 도움이 된다. The oligomer represented by the formula (1) exhibits a balanced affinity with the positive electrode or separator (SRS layer) and the negative electrode or separator fabric in the secondary battery is electrochemically stable, which is a great help in improving lithium secondary battery performance.
즉, 상기 화학식 1로 표시되는 올리고머는 양 말단에 자체적으로 가교 결합을 형성할 수 있는 친수성 부분인 아크릴레이트계 작용기를 함유하는 동시에, 소수성 부분인 불소 치환 에틸렌기를 포함하고 있기 때문에, 전지 내에서 계면활성제 역할을 부여하여, 양극, 음극 및 분리막(SRS층)과 각각 균형적인 친화성을 유지하여 계면 저항을 낮출 수 있다. 따라서, 상기 화학식 1로 표시되는 올리고머를 포함하는 리튬 이차전지용 전해질은 젖음성 효과가 보다 향상될 수 있다. That is, the oligomer represented by the formula (1) contains an acrylate-based functional group which is a hydrophilic part capable of forming crosslinking at both ends thereof, and also contains a fluorine-substituted ethylene group which is a hydrophobic part, and thus is an interface in a battery. By imparting an activator role, the interfacial resistance can be lowered by maintaining balanced affinity with the positive electrode, the negative electrode, and the separator (SRS layer), respectively. Therefore, the electrolyte for a lithium secondary battery including the oligomer represented by Chemical Formula 1 may further improve the wettability effect.
뿐만 아니라, 상기 화학식 1로 표시되는 올리고머는 리튬염을 해리하는 능력을 보유하고 있어 리튬 이온 이동성을 향상시킬 수 있고, 특히 말단에 불소로 치환된 알킬기를 포함하는 동시에, 주사슬의 반복단위로 전기화학적으로 매우 안정하고, Li 이온과의 반응성이 낮은 불소 치환 에틸렌기를 포함하고 있기 때문에, 초기 충전시 전극 표면에 안정한 이온전도성 피막을 형성함으로써 고온 저장 및 과충전 시에 전해질과 리튬 이온(Li+)과의 부반응, 전해질 산화 반응 및 리튬염(salt)의 분해 반응 등을 제어할 수 있다.In addition, the oligomer represented by the formula (1) has the ability to dissociate lithium salts to improve the lithium ion mobility, in particular containing an alkyl group substituted with fluorine at the end, and at the same time repeating Since it contains a fluorine-substituted ethylene group which is very chemically stable and has low reactivity with Li ions, a stable ion conductive film is formed on the surface of the electrode during initial charging, so that the electrolyte and lithium ions (Li + ) and Side reactions, electrolyte oxidation reactions and decomposition reactions of lithium salts can be controlled.
따라서, 과충전 시에 CO 또는 CO2 등의 가스 발생을 저감할 수 있으므로, 고온 내구성을 향상시킬 수 있다. Thus, it is possible to reduce the gas generation, such as CO or CO 2 at the time of overcharging, it is possible to improve the high-temperature durability.
이에, 종래 겔 폴리머 전해질 제조 시에 상용화되었던 에틸렌 옥사이드, 프로필렌 옥사이드, 또는 부틸렌 옥사이드 등의 알킬렌 옥사이드 골격을 가지는 폴리머, 또는 디알킬 실록산, 플루오로실록산, 또한 이들의 유닛을 가진 블록 공중합체 및 그라프트 중합체 등 대신에 상기 화학식 1로 표시되는 올리고머를 포함하는 본 발명의 이차전지용 전해질은 전해질 부반응 및 산화 반응이 감소하여, 전극과 전해질 사이의 계면 안정성 효과를 구현함으로써, 고온 내구성이 향상될 수 있다.Thus, a polymer having an alkylene oxide skeleton such as ethylene oxide, propylene oxide, or butylene oxide, which has been commercialized at the time of preparing a gel polymer electrolyte, or a block copolymer having a dialkyl siloxane, a fluorosiloxane, or a unit thereof; The secondary battery electrolyte of the present invention including the oligomer represented by Chemical Formula 1 in place of the graft polymer may reduce electrolyte side reactions and oxidation reactions, thereby realizing an interfacial stability effect between the electrode and the electrolyte, thereby improving high temperature durability. have.
이때, 상기 화학식 1로 표시되는 올리고머에서, At this time, in the oligomer represented by Formula 1,
상기 지방족 탄화수소기는 치환 또는 비치환된 탄소수 4 내지 20의 사이클로알킬렌기; 이소시아네이트기(NCO)를 함유하는 치환 또는 비치환된 탄소수 4 내지 20의 사이클로알킬렌기; 치환 또는 비치환된 탄소수 4 내지 20의 사이클로알케닐렌기; 및 치환 또는 비치환된 탄소수 2 내지 20의 헤테로사이클로알킬렌기로 이루어진 군으로부터 선택된 적어도 하나 이상의 지환족 탄화수소기, 또는 치환 또는 비치환된 탄소수 1 내지 20의 알킬렌기; 이소시아네이트기(NCO)를 함유하는 치환 또는 비치환된 탄소수 1 내지 20의 알킬렌기; 치환 또는 비치환된 탄소수 1 내지 20의 알콕실렌기; 치환 또는 비치환된 탄소수 2 내지 20의 알케닐렌기; 및 치환 또는 비치환된 탄소수 2 내지 20의 알키닐렌기로 이루어진 군으로부터 선택된 선형 탄화수소기이고, The aliphatic hydrocarbon group may be substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms; A substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms containing an isocyanate group (NCO); A substituted or unsubstituted cycloalkenylene group having 4 to 20 carbon atoms; And at least one alicyclic hydrocarbon group selected from the group consisting of a substituted or unsubstituted heterocycloalkylene group having 2 to 20 carbon atoms, or a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms; Substituted or unsubstituted C1-C20 alkylene group containing an isocyanate group (NCO); A substituted or unsubstituted alkoxylene group having 1 to 20 carbon atoms; A substituted or unsubstituted alkenylene group having 2 to 20 carbon atoms; And a linear hydrocarbon group selected from the group consisting of substituted or unsubstituted alkynylene group having 2 to 20 carbon atoms,
상기 방향족 탄화수소기는 치환 또는 비치환된 탄소수 6 내지 20의 아릴렌기; 또는 치환 또는 비치환된 탄소수 2 내지 20의 헤테로아릴렌기일 수 있다.The aromatic hydrocarbon group is substituted or unsubstituted arylene group having 6 to 20 carbon atoms; Or a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms.
구체적으로, 상기 화학식 1로 표시되는 올리고머는 하기 화학식 1a로 표시되는 올리고머일 수 있다.Specifically, the oligomer represented by Formula 1 may be an oligomer represented by Formula 1a.
[화학식 1a][Formula 1a]
Figure PCTKR2017014432-appb-I000005
Figure PCTKR2017014432-appb-I000005
상기 화학식 1a에서,In Chemical Formula 1a,
R은 지방족 탄화수소기 또는 방향족 탄화수소기이고,R is an aliphatic hydrocarbon group or an aromatic hydrocarbon group,
R1은 불소로 치환 또는 비치환된 탄소수 1 내지 5의 알킬렌기이고, R 1 is an alkylene group having 1 to 5 carbon atoms substituted or unsubstituted with fluorine,
n1은 반복단위 수이며,n1 is the number of repeat units,
m1은 1 내지 75 중 어느 하나의 정수이다.m1 is an integer of any one of 1-75.
더욱 구체적으로, 상기 화학식 1a로 표시되는 올리고머는 하기 화학식 1a-1로 표시되는 올리고머일 수 있다.More specifically, the oligomer represented by Formula 1a may be an oligomer represented by Formula 1a-1.
[화학식 1a-1][Formula 1a-1]
Figure PCTKR2017014432-appb-I000006
Figure PCTKR2017014432-appb-I000006
상기 화학식 1a-1에서, In Chemical Formula 1a-1,
n2는 반복단위 수이며,n2 is the number of repeat units,
n2는 20 내지 75 중 어느 하나의 정수다.n2 is an integer of any one of 20-75.
상기 화학식 1로 표시되는 올리고머는 리튬 이차전지용 전해질 전체 중량을 기준으로 0.5 중량% 내지 20 중량%, 구체적으로 0.5 중량% 내지 15 중량%, 보다 구체적으로 0.5 중량% 내지 10 중량%로 포함될 수 있다.The oligomer represented by Chemical Formula 1 may be included in an amount of 0.5 wt% to 20 wt%, specifically 0.5 wt% to 15 wt%, and more specifically 0.5 wt% to 10 wt%, based on the total weight of the lithium secondary battery electrolyte.
상기 화학식 1로 표시되는 올리고머의 함량이 0.5 중량% 이상인 경우에 안정한 네트워크 구조를 가지는 겔 폴리머 전해질을 제조할 수 있고, 20 중량% 이하인 경우에 과량의 올리고머 첨가에 따른 저항 증가를 방지하여 젖음성을 확보함과 동시에, 리튬 이온의 이동 제한을 개선하여 이온전도도 저하와 같은 단점을 방지할 수 있다. When the content of the oligomer represented by Formula 1 is 0.5% by weight or more, a gel polymer electrolyte having a stable network structure may be prepared, and when the content of the oligomer is 20% by weight or less, an increase in resistance due to the addition of an excessive oligomer is prevented to ensure wettability. At the same time, it is possible to prevent the disadvantages such as lowering the ion conductivity by improving the movement restriction of lithium ions.
또한, 상기 화학식 1로 표시되는 올리고머의 중량평균분자량(MW)은 반복 단위의 개수에 의해 조절될 수 있으며, 약 1,000 g/mol 100,000 g/mol, 구체적으로 1,000 g/mol 내지 50,000 g/mol, 더욱 구체적으로 2,000 g/mol 내지 7,000 g/mol 일 수 있다. 상기 올리고머의 중량평균분자량이 상기 범위 내인 경우, 적절한 올리고머 분자량에 의한 폴리머 매트릭스를 효과적으로 형성할 수 있다. 아울러, 필요에 따라 여러가지 관능기를 치환시키기 용이하기 때문에, 다양한 제반 성능 개선 효과를 얻을 수 있다. In addition, the weight average molecular weight (MW) of the oligomer represented by Formula 1 may be adjusted by the number of repeating units, about 1,000 g / mol 100,000 g / mol, specifically 1,000 g / mol to 50,000 g / mol, More specifically, it may be 2,000 g / mol to 7,000 g / mol. When the weight average molecular weight of the oligomer is in the above range, it is possible to effectively form a polymer matrix by the appropriate oligomer molecular weight. In addition, since various functional groups can be easily substituted as necessary, various various performance improvement effects can be obtained.
만약, 상기 올리고머의 중량 평균분자량이 1,000 g/mol 미만이면, 안정한 폴리머 네트워크 형성이 어렵기 때문에 자체적인 전기화학적 안정성 및 계면활성제의 역할 등을 기대할 수 없고, 중량평균분자량이 100,000 g/mol을 초과하면, 올리고머 물성 자체가 경직(rigid)되고, 점도 증가에 의해 전해질 용매와 친화성이 낮아져 용해도(solubility)가 낮아지는 단점이 있다. If the weight average molecular weight of the oligomer is less than 1,000 g / mol, since it is difficult to form a stable polymer network, its own electrochemical stability and the role of a surfactant cannot be expected, and the weight average molecular weight exceeds 100,000 g / mol. In other words, the oligomer properties are rigid and the affinity with the electrolyte solvent is lowered due to the increase in viscosity, so that the solubility is lowered.
상기 중량평균분자량은 겔투과크로마토그래피(Gel Permeation Chromatography: GPC)로 측정한 표준 폴리스티렌에 대한 환산 수치를 의미할 수 있고, 특별하게 달리 규정하지 않는 한, 분자량은 중량평균분자량을 의미할 수 있다. 예컨대, 본 발명에서는 GPC 조건으로 Agilent社 1200시리즈를 이용하여 측정하며, 이때 사용된 컬럼은 Agilent社 PL mixed B 컬럼을 이용할 수 있고, 용매는 THF를 사용할 수 있다.The weight average molecular weight may mean a conversion value for standard polystyrene measured by gel permeation chromatography (GPC), and unless otherwise specified, molecular weight may mean weight average molecular weight. For example, in the present invention, the GPC conditions are measured using Agilent's 1200 series, and the column used may be an Agilent PL mixed B column, and the solvent may be THF.
이러한 본 발명의 일 실시예에 따른 리튬 이차전지용 전해질이 상기 화학식 1로 표시되는 올리고머를 포함하는 경우, 상기 본 발명의 리튬 이차전지용 전해질은 액체 전해질일 수 있다.When the lithium secondary battery electrolyte according to one embodiment of the present invention includes the oligomer represented by Formula 1, the lithium secondary battery electrolyte of the present invention may be a liquid electrolyte.
또한, 본 발명의 일 실시예에 따른 리튬 이차전지용 전해질이 상기 화학식 1로 표시되는 올리고머 유래의 폴리머를 포함하는 경우, 상기 리튬 이차전지용 전해질은 겔 폴리머 전해질일 수 있다.In addition, when the lithium secondary battery electrolyte according to an embodiment of the present invention includes a polymer derived from the oligomer represented by the formula (1), the lithium secondary battery electrolyte may be a gel polymer electrolyte.
이때, 상기 화학식 1로 표시되는 올리고머 유래의 폴리머는 중합개시제 존재하에서 화학식 1로 표시되는 올리고머가 중합하여 3차원 구조로 형성된 매트릭스 폴리머일 수 있다.In this case, the polymer derived from the oligomer represented by Formula 1 may be a matrix polymer formed in a three-dimensional structure by polymerization of the oligomer represented by Formula 1 in the presence of a polymerization initiator.
상기 본 발명의 리튬 이차전지용 전해질이 겔 폴리머 전해질일 경우, 겔을 형성하기 위하여 사용되는 중합개시제는 통상적인 겔 폴리머 전해질 제조 시 사용되는 열 및 광에 의하여 라디칼을 발생시킬 수 있는 통상적인 중합개시제를 제한 없이 사용할 수 있다. 구체적으로, 상기 중합개시제는 아조계 중합개시제 또는 퍼옥사이드계 중합개시제를 사용할 수 있으며, 그 대표적인 예로 벤조일 퍼옥사이드(benzoyl peroxide), 아세틸 퍼옥사이드(acetyl peroxide), 디라우릴 퍼옥사이드(dilauryl peroxide), 디-tert-부틸 퍼옥사이드(di-tert-butyl peroxide), t-부틸 퍼옥시-2-에틸-헥사노에이트(t-butyl peroxy-2-ethyl-hexanoate), 큐밀 하이드로퍼옥사이드(cumyl hydroperoxide) 및 하이드로겐 퍼옥사이드(hydrogen peroxide)로 이루어진 군으로부터 선택된 적어도 하나 이상의 퍼옥사이드계 화합물, 또는 2,2'-아조비스(2-시아노부탄), 디메틸 2,2'-아조비스(2-메틸프로피오네이트), 2,2'-아조비스(메틸부티로니트릴), 2,2'-아조비스(이소부티로니트릴)(AIBN; 2,2'-Azobis(iso-butyronitrile)) 및 2,2'-아조비스디메틸-발레로니트릴(AMVN; 2,2'-Azobisdimethyl-valeronitrile)로 이루어진 군으로부터 선택된 적어도 하나 이상의 아조계 화합물을 들 수 있다.When the electrolyte for a lithium secondary battery of the present invention is a gel polymer electrolyte, a polymerization initiator used to form a gel may be a conventional polymerization initiator capable of generating radicals by heat and light used in preparing a conventional gel polymer electrolyte. Can be used without limitation. Specifically, the polymerization initiator may use an azo polymerization initiator or a peroxide polymerization initiator, and representative examples thereof include benzoyl peroxide, acetyl peroxide, dilauryl peroxide, Di-tert-butyl peroxide, t-butyl peroxy-2-ethyl-hexanoate, cumyl hydroperoxide And at least one peroxide compound selected from the group consisting of hydrogen peroxide, or 2,2'-azobis (2-cyanobutane), dimethyl 2,2'-azobis (2-methyl Propionate), 2,2'-azobis (methylbutyronitrile), 2,2'-azobis (isobutyronitrile) (AIBN; 2,2'-Azobis (iso-butyronitrile)) and 2, Group consisting of 2'-azobisdimethyl-valeronitrile (AMVN; 2,2'-Azobisdimethyl-valeronitrile) Emitter may include at least one azo compound selected.
상기 중합개시제는 이차전지 내에서 열, 비제한적인 예로 30℃ 내지 100℃, 구체적으로 60℃ 내지 80℃의 열에 의해 분해되거나 상온(5℃ 내지 30℃)에서 분해되어 라디칼을 형성할 수 있다. The polymerization initiator may be decomposed by heat in the secondary battery, for example, but not limited to 30 ° C. to 100 ° C., specifically 60 ° C. to 80 ° C., or may be decomposed at room temperature (5 ° C. to 30 ° C.) to form radicals.
상기 중합개시제는 상기 올리고머 전체 100 중량부를 기준으로 약 0.01 중량부 내지 약 20 중량부, 구체적으로 5 중량부로 포함될 수 있으며, 상기 범위로 포함되는 경우 겔화 반응을 용이하게 실시하여, 조성물을 전지 내에 주액하는 도중 겔화가 일어나거나, 중합 반응 후 미반응 중합개시제가 남아 부반응을 야기하는 것을 방지할 수 있다. 특히, 일부 중합개시제의 경우 열 등에 의하여 라디칼이 발생하는 과정에서 질소 혹은 산소 가스가 발생하기도 한다. 이러한 가스 발생은 겔 고분자 전해질 형성 과정에서 가스 트랩 또는 가스 버블링 현상으로 이어지는 경우가 대다수이다. 이러한 가스 발생의 경우 겔 고분자 전해질 내에서 결함(defect)를 야기하기 때문에 전해질 품질 저하로 나타난다. 따라서, 중합개시제가 상기 범위로 포함되는 경우 가스가 다량 발생하는 등의 단점을 보다 효과적으로 방지할 수 있다. The polymerization initiator may be included in about 0.01 parts by weight to about 20 parts by weight, specifically 5 parts by weight based on 100 parts by weight of the total oligomer, and if included in the above range to facilitate the gelling reaction, the composition is injected into a battery It is possible to prevent the gelation occurs during the operation, or the unreacted polymerization initiator remains after the polymerization reaction to cause side reactions. In particular, some polymerization initiators may generate nitrogen or oxygen gas in the process of generating radicals by heat or the like. This gas generation is often lead to gas trap or gas bubbling phenomenon in the gel polymer electrolyte formation process. This gas generation causes a defect in the gel polymer electrolyte, resulting in a decrease in electrolyte quality. Therefore, when the polymerization initiator is included in the above range, it is possible to more effectively prevent the disadvantages such as the generation of a large amount of gas.
특히, 일부 중합개시제의 경우 열 등에 의하여 라디칼이 발생하는 과정에서 질소 혹은 산소 가스가 발생하기도 한다. 이러한 가스 발생은 겔 고분자 전해질 형성 과정에서 가스 트랩 또는 가스 버블링 현상으로 이어지는 경우가 대다수이다. 이러한 가스 발생의 경우 겔 고분자 전해질 내에서 결함(defect)을 야기하기 때문에 전해질 품질 저하로 나타난다. 따라서, 중합개시제가 상기 범위로 포함되는 경우 가스가 다량 발생하는 등의 단점을 보다 효과적으로 방지할 수 있다. 또한, 발명의 겔 폴리머 전해질에 있어서, 상기 겔 폴리머 전해질은 25℃ 온도에서 겔 함량이 약 1 중량% 이상, 구체적으로 약 20 중량% 이상일 수 있다. In particular, some polymerization initiators may generate nitrogen or oxygen gas in the process of generating radicals by heat or the like. This gas generation is often lead to gas trap or gas bubbling phenomenon in the gel polymer electrolyte formation process. This gas generation causes a defect in the gel polymer electrolyte, resulting in electrolyte quality deterioration. Therefore, when the polymerization initiator is included in the above range, it is possible to more effectively prevent the disadvantages such as the generation of a large amount of gas. In addition, in the gel polymer electrolyte of the present invention, the gel polymer electrolyte may have a gel content of about 1% by weight or more, specifically about 20% by weight or more at 25 ° C.
또한, 본 발명의 겔 폴리머 전해질은 무기물 입자를 추가로 포함할 수 있다.In addition, the gel polymer electrolyte of the present invention may further include inorganic particles.
상기 무기물 입자는 폴리머 네트워크에 함침되어, 무기물 입자 간의 빈공간에 의해 형성된 기공들을 통하여 고점도 용매가 잘 스며들도록 할 수 있다. 즉, 무기물 입자를 포함함으로써, 극성 물질 간의 친화력과 모세관 현상에 의해 고점도 용매에 대한 습윤성을 보다 향상되는 효과를 얻을 수 있다.The inorganic particles may be impregnated in the polymer network to allow the high viscosity solvent to penetrate well through the pores formed by the void space between the inorganic particles. That is, by including the inorganic particles, it is possible to obtain an effect of further improving the wettability to a high viscosity solvent by affinity between the polar substances and capillary phenomenon.
이러한 무기물 입자로는 유전율이 높고, 리튬 이차전지의 작동 전압 범위(예컨대, Li/Li+ 기준으로 0 내지 5V)에서 산화 및/또는 환원 반응이 일어나지 않는 무기물 입자를 사용할 수 있다. As such inorganic particles, inorganic particles having a high dielectric constant and which do not generate an oxidation and / or reduction reaction in an operating voltage range of the lithium secondary battery (for example, 0 to 5V based on Li / Li + ) may be used.
구체적으로, 상기 무기물 입자는 그 대표적인 예로서 유전율 상수가 5 이상인 BaTiO3, BaTiO3, Pb(ZrxTi1-x)O3 (0≤x≤1) (PZT), Pb1 - bLabZr1 - cTicO3 (PLZT, 여기서, 0<b<1, 0<c<1임), Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT), 하프니아(HfO2), SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiC 및 이들의 혼합체로부터 이루어진 군으로부터 선택된 단일물 또는 2종 이상의 혼합물을 들 수 있다. Specifically, the inorganic particles are representative examples of BaTiO 3 , BaTiO 3 , Pb (Zr x Ti 1-x ) O 3 (0 ≦ x ≦ 1) (PZT), Pb 1 − b La b having a dielectric constant of 5 or more. Zr 1 - c Ti c O 3 (PLZT, where 0 <b <1, 0 <c <1), Pb (Mg 1/3 Nb 2/3 ) O 3 -PbTiO 3 (PMN-PT), half Single substance selected from the group consisting of nia (HfO 2 ), SrTiO 3 , SnO 2 , CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 , Al 2 O 3 , TiO 2 , SiC and mixtures thereof Or a mixture of two or more thereof.
또한, 상기 무기물 입자 외에도 리튬 이온 전달 능력을 갖는 무기물 입자, 즉 리튬포스페이트 (Li3PO4), 리튬티타늄포스페이트 (LidTie(PO4)3, 0<d<2, 0<e<3), 리튬알루미늄티타늄포스페이트 (Lia1Alb1Tic1(PO4)3, 0<a1<2, 0<b1<1, 0<c1<3), 14Li2O-9Al2O3-38TiO2-39P2O5 등과 같은 (LiAlTiP)a2Ob2 계열 글래스(glass) (0<a2<4, 0<b2<13), 리튬란탄티타네이트 (Lia3Lab3TiO3, 0<a3<2, 0<b3<3), Li3 . 25Ge0 .25P0. 75S4 등과 같은 리튬게르마니움티오포스페이트 (Lia4Geb4Pc2Sd1, 0<a4<4, 0<b4<1, 0<c2<1, 0<d1<5), Li3N 등과 같은 리튬나이트라이드 (Lia5Nb5, 0<a5<4, 0<b5<2), Li3PO4-Li2S-SiS2 등과 같은 SiS2 계열 글래스 (Lia6Sib6Sc3, 0<a6<3, 0<b6<2, 0<c3<4), LiI-Li2S-P2S5 등과 같은 P2S5 계열 글래스 (Lia7Pb7Sc4, 0<a7<3, 0<b7<3, 0<c4<7) 또는 이들의 혼합물 등을 더 포함할 수 있다. Further, in addition to the inorganic particles, inorganic particles having lithium ion transfer ability, that is, lithium phosphate (Li 3 PO 4 ), lithium titanium phosphate (Li d Ti e (PO 4 ) 3 , 0 <d <2, 0 <e <3 ), Lithium aluminum titanium phosphate (Li a1 Al b1 Ti c1 (PO 4 ) 3 , 0 <a1 <2, 0 <b1 <1, 0 <c1 <3), 14Li 2 O-9Al 2 O 3 -38TiO 2- (LiAlTiP) a2 O b2 series glass such as 39P 2 O 5 (0 <a2 <4, 0 <b2 <13), lithium lanthanum titanate (Li a3 La b3 TiO 3 , 0 <a3 <2, 0 <b3 <3), Li 3 . 25 Ge 0 .25 P 0. 75 S 4 Mani lithium germanium thiophosphate Titanium (Li a4 Ge b4 P c2 S d1, 0 <a4 <4, 0 <b4 <1, 0 <c2 <1, 0 <d1 such as <5), lithium nitrides such as Li 3 N (Li a5 N b5 , 0 <a5 <4, 0 <b5 <2), and SiS 2 series glasses such as Li 3 PO 4 -Li 2 S-SiS 2 (Li a6 Si b6 S c3, 0 < a6 <3, 0 <b6 <2, 0 <c3 <4), P 2 , such as LiI-Li 2 SP 2 S 5 S 5 based glass (Li a7 P b7 S c4, 0 <a7 <3, 0 <b7 <3, 0 <c4 <7) or mixtures thereof, and the like.
상기 무기물 입자는 리튬 이차전지용 전해질 전체 중량을 기준으로 10 중량% 내지 25 중량%로 포함될 수 있다.The inorganic particles may be included in 10% by weight to 25% by weight based on the total weight of the electrolyte for a lithium secondary battery.
상기 무기물 입자 함량이 10 중량% 미만인 경우에 고점도 용매에서 젖음성 (wetting) 개선 효과를 기대하기 어렵고, 25 중량%를 초과하는 경우 전지의 저항 성능저하를 유발 할 수 있다. When the inorganic particle content is less than 10% by weight, it is difficult to expect an effect of improving wetting in a high viscosity solvent, and when it exceeds 25% by weight, it may cause a decrease in resistance performance of the battery.
상기 무기물 입자들의 평균 입경은 겔 폴리머 전해질 내에 균일한 두께로 적절한 공극률을 가지도록 형성하기 위하여, 약 0.001㎛ 내지 10㎛ 범위인 것이 바람직하다. 만약, 평균 입경이 0.001㎛ 미만인 경우 분산성이 저하될 수 있고, 평균 입경이 10㎛를 초과하는 경우 다공성 코팅층의 두께가 증가할 수 있을 뿐만 아니라, 무기물 입자가 뭉치는 현상이 발생하여 겔 폴리머 전해질 밖으로 노출되면서 기계적 강도가 저하될 수 있다. The average particle diameter of the inorganic particles is preferably in the range of about 0.001 μm to 10 μm so as to have a proper porosity with a uniform thickness in the gel polymer electrolyte. If the average particle size is less than 0.001㎛ dispersibility may be lowered, if the average particle diameter is more than 10㎛ not only can increase the thickness of the porous coating layer, but also agglomeration of inorganic particles occurs gel gel electrolyte Exposure to the outside can lower the mechanical strength.
또한, 상기 겔 폴리머 전해질은 25℃ 온도에서 반응성 올리고머 전체 투입량 대비 미반응 올리고머의 함량이 20% 이하일 수 있다.In addition, the gel polymer electrolyte may have a content of unreacted oligomers of 20% or less relative to the total amount of reactive oligomers at 25 ° C.
이때, 상기 미반응 올리고머의 함량은 겔 폴리머 전해질을 구현한 다음, 겔 폴리머 전해질을 용매 (아세톤) 추출하고, 이어서 추출된 용매를 핵자기 공명(NMR) 측정을 통해 확인할 수 있다.In this case, the content of the unreacted oligomer may be implemented by implementing a gel polymer electrolyte, extracting the gel polymer electrolyte with a solvent (acetone), and then checking the extracted solvent through nuclear magnetic resonance (NMR) measurement.
또한, 본 발명의 일 실시예에 따른 리튬 이차전지용 전해질은 필요에 따라서 SEI 막 형성용 첨가제를 더 포함할 수도 있다. 본 발명에서 사용 가능한 SEI 막 형성용 첨가제는 그 대표적인 예로 비닐렌 카보네이트, 비닐에틸렌 카보네이트, 플루오로에틸렌 카보네이트, 환형 설파이트, 포화 설톤, 불포화 설톤, 비환형 설폰 등을 각각 단독으로 또는 2종 이상 혼합하여 사용할 수 있다.In addition, the electrolyte for a lithium secondary battery according to an embodiment of the present invention may further include an additive for forming an SEI film as needed. SEI film-forming additives usable in the present invention are representative examples thereof, such as vinylene carbonate, vinylethylene carbonate, fluoroethylene carbonate, cyclic sulfite, saturated sultone, unsaturated sultone, acyclic sulfone, etc., alone or in combination of two or more thereof. Can be used.
이때, 상기 환형 설파이트로는 에틸렌 설파이트, 메틸 에틸렌 설파이트, 에틸 에틸렌 설파이트, 4,5-디메틸 에틸렌 설파이트, 4,5-디에틸 에틸렌 설파이트, 프로필렌 설파이트, 4,5-디메틸 프로필렌 설파이트, 4,5-디에틸 프로필렌설파이트, 4,6-디메틸 프로필렌 설파이트, 4,6-디에틸 프로필렌 설파이트, 1,3-부틸렌 글리콜 설파이트 등을 들 수 있으며, 포화 설톤으로는 1,3-프로판 설톤, 1,4-부탄 설톤 등을 들 수 있으며, 불포화 설톤으로는 에텐설톤, 1,3-프로펜 설톤, 1,4-부텐 설톤, 1-메틸-1,3-프로펜 설톤 등을 들 수 있으며, 비환형 설폰으로는 디비닐설폰, 디메틸 설폰, 디에틸 설폰, 메틸에틸 설폰, 메틸비닐 설폰 등을 들 수 있다.At this time, the cyclic sulfites include ethylene sulfite, methyl ethylene sulfite, ethyl ethylene sulfite, 4,5-dimethyl ethylene sulfite, 4,5-diethyl ethylene sulfite, propylene sulfite, 4,5-dimethyl Propylene sulfite, 4,5-diethyl propylene sulfite, 4,6-dimethyl propylene sulfite, 4,6-diethyl propylene sulfite, 1,3-butylene glycol sulfite, and the like. Examples thereof include 1,3-propane sultone and 1,4-butane sultone. Examples of unsaturated sultone include ethene sultone, 1,3-propene sultone, 1,4-butene sultone, 1-methyl-1,3 -Propene sulfone, and the like, and acyclic sulfones include divinyl sulfone, dimethyl sulfone, diethyl sulfone, methylethyl sulfone, and methyl vinyl sulfone.
이때, 상기 SEI 막 형성용 첨가제는 첨가제 과량 사용에 따른 저항 증가 및 부반응 방지를 위하여 리튬 이차전지용 전해질 전체 중량을 기준으로 7 중량% 이하, 구체적으로 0.01 중량% 내지 5 중량%로 포함되는 것이 바람직하다.In this case, the additive for forming the SEI film is preferably included 7 wt% or less, specifically 0.01 wt% to 5 wt% based on the total weight of the electrolyte for the lithium secondary battery in order to increase resistance and prevent side reactions due to the use of additives in excess. .
이러한 본 발명의 겔 폴리머 전해질은 상기 화학식 1로 표시되는 올리고머가 중합하여 3차원 구조로 형성된 매트릭스 폴리머를 포함함으로써, 기계적 물성 및 이온전도도 향상 효과뿐만 아니라, 고온 저장 및 과충전 시에 산화 반응이 억제되어 고온 내구성을 확보할 수 있다. 아울러, 양극과 음극 표면에 고분자로 구성되는 보호층을 형성하거나, 고분자 구조를 이용하여 음이온 안정화를 통한 부반응 억제 및 전극간의 밀착력을 증대시켜 고온에서의 전지 내부의 가스 발생을 억제할 수 있다. 따라서, 고온 저장 및 과충전 시에 안정성이 향상된 리튬 이차전지를 제조할 수 있다. Since the gel polymer electrolyte of the present invention includes a matrix polymer formed by polymerizing the oligomer represented by Chemical Formula 1 in a three-dimensional structure, not only the mechanical properties and the ionic conductivity are improved, but also the oxidation reaction is inhibited during high temperature storage and overcharge. High temperature durability can be ensured. In addition, by forming a protective layer made of a polymer on the surface of the positive electrode and the negative electrode, or by using a polymer structure to suppress side reactions through anion stabilization and to increase the adhesion between the electrodes can suppress the generation of gas inside the battery at a high temperature. Therefore, a lithium secondary battery having improved stability at high temperature storage and overcharging may be manufactured.
또한, 본 발명의 일 실시예에서는In addition, in one embodiment of the present invention
음극, 양극, 상기 음극 및 양극 사이에 개재된 분리막, 및A cathode interposed between the cathode, the anode, the cathode and the anode, and
본 발명의 리튬 이차전지용 전해질을 포함하는 리튬 이차전지를 제공할 수 있다.It is possible to provide a lithium secondary battery comprising the electrolyte for a lithium secondary battery of the present invention.
상기 리튬 이차전지용 전해질은 액체 전해질 또는 겔 폴리머 전해질일 수 있다.The lithium secondary battery electrolyte may be a liquid electrolyte or a gel polymer electrolyte.
상기 리튬 이차전지용 전해질이 액체 전해질인 경우, 본 발명의 리튬 이차전지는 양극, 음극 및 양극과 음극 사이에 선택적으로 개재된 분리막이 순차적으로 적층되어 이루어진 전극조립체를 이차전지 케이스 또는 외장재에 수납한 다음, 본 발명의 리튬 이차전지용 전해질을 주입하여 제조할 수 있다. When the electrolyte for the lithium secondary battery is a liquid electrolyte, the lithium secondary battery of the present invention accommodates an electrode assembly formed by sequentially stacking a separator interposed between a positive electrode, a negative electrode, and a positive electrode and a negative electrode in a secondary battery case or an exterior material. It can be prepared by injecting the electrolyte for a lithium secondary battery of the present invention.
또한, 상기 리튬 이차전지용 전해질이 상기 화학식 1로 표시되는 올리고머의 중합에 의해 형성된 폴리머 매트릭스를 포함하는 겔 폴리머 전해질인 경우, 본 발명의 리튬 이차전지는 양극, 음극, 및 양극과 음극 사이에 선택적으로 개재된 분리막이 순차적으로 적층되어 이루어진 전극조립체를 이차전지 케이스 또는 외장재에 수납한 다음, 상기 리튬 이차전지용 전해질을 주입한 후 경화 반응시켜 제조될 수 있다.In addition, when the lithium secondary battery electrolyte is a gel polymer electrolyte containing a polymer matrix formed by the polymerization of the oligomer represented by the formula (1), the lithium secondary battery of the present invention selectively between the positive electrode, the negative electrode, and the positive electrode and the negative electrode The electrode assembly formed by sequentially stacking the intervening separator may be accommodated in a secondary battery case or an exterior member, and then injected into the lithium secondary battery electrolyte, followed by curing reaction.
예를 들면, 이차전지의 내부에서 리튬 이차전지용 전해질을 주입한 in-situ 중합 반응을 실시하여 형성될 수 있다. 상기 in-situ 중합 반응은 전자빔(E-BEAM), 감마선, 상온 또는 고온 에이징 공정을 통하여 가능하며, 본 발명의 일 실시예에 따르면 열 중합을 통해 진행될 수 있다. 이때, 중합 시간은 대략 2분 내지 48시간 정도 소요되며, 열 중합 온도는 60℃ 내지 100℃, 구체적으로 60℃ 내지 80℃ 가 될 수 있다.For example, it may be formed by performing an in-situ polymerization reaction in which an electrolyte for a lithium secondary battery is injected into the secondary battery. The in-situ polymerization reaction is possible through an electron beam (E-BEAM), gamma rays, room temperature or high temperature aging process, according to an embodiment of the present invention may be carried out through thermal polymerization. At this time, the polymerization time takes about 2 minutes to 48 hours, the thermal polymerization temperature may be 60 ℃ to 100 ℃, specifically 60 ℃ to 80 ℃.
한편, 본 발명의 리튬 이차전지에서 상기 양극, 음극 및 분리막은 리튬 이차전지 제조 시에 통상적인 방법으로 제조되어 사용되던 것들이 모두 사용될 수 있다.On the other hand, in the lithium secondary battery of the present invention, the positive electrode, the negative electrode and the separator may be used all those prepared and used in a conventional manner when manufacturing a lithium secondary battery.
먼저, 상기 양극은 양극 집전체 상에 양극 합제층을 형성하여 제조할 수 있다. 상기 양극 합제층은 양극활물질, 바인더, 도전재 및 용매 등을 포함하는 양극 활물질 슬러리를 양극 집전체 상에 코팅한 후, 건조 및 압연하여 형성할 수 있다.First, the positive electrode may be manufactured by forming a positive electrode mixture layer on a positive electrode current collector. The cathode mixture layer may be formed by coating a cathode active material slurry including a cathode active material, a binder, a conductive material, a solvent, and the like on a cathode current collector, followed by drying and rolling.
상기 양극 집전체는 당해 전지에 화학적 변화를 유발하지 않으면서 도전성을 가진 것이라면 특별히 제한되는 것은 아니며, 예를 들어, 스테인리스 스틸, 알루미늄, 니켈, 티탄, 소성 탄소, 또는 알루미늄이나 스테인리스 스틸의 표면에 카본, 니켈, 티탄, 은 등으로 표면 처리한 것 등이 사용될 수 있다. The positive electrode current collector is not particularly limited as long as it has conductivity without causing chemical changes in the battery. For example, the positive electrode current collector may be formed of stainless steel, aluminum, nickel, titanium, calcined carbon, or carbon on the surface of aluminum or stainless steel. Surface treated with nickel, titanium, silver, or the like may be used.
상기 양극 활물질은 리튬의 가역적인 인터칼레이션 및 디인터칼레이션이 가능한 화합물로서, 구체적으로는 코발트, 망간, 니켈 또는 알루미늄과 같은 1종 이상의 금속과 리튬을 포함하는 리튬 복합금속 산화물을 포함할 수 있다. 보다 구체적으로, 상기 리튬 복합금속 산화물은 리튬-망간계 산화물(예를 들면, LiMnO2, LiMn2O4 등), 리튬-코발트계 산화물(예를 들면, LiCoO2 등), 리튬-니켈계 산화물(예를 들면, LiNiO2 등), 리튬-니켈-망간계 산화물(예를 들면, LiNi1 - YMnYO2(여기에서, 0<Y<1), LiMn2 - zNizO4(여기에서, 0＜Z＜2) 등), 리튬-니켈-코발트계 산화물(예를 들면, LiNi1 - Y1CoY1O2(여기에서, 0<Y1<1) 등), 리튬-망간-코발트계 산화물(예를 들면, LiCo1-Y2MnY2O2(여기에서, 0<Y2<1), LiMn2 - z1Coz1O4(여기에서, 0＜Z1＜2) 등), 리튬-니켈-망간-코발트계 산화물(예를 들면, Li(NipCoqMnr1)O2(여기에서, 0＜p＜1, 0＜q＜1, 0＜r1＜1, p+q+r1=1) 또는 Li(Nip1Coq1Mnr2)O4(여기에서, 0＜p1＜2, 0＜q1＜2, 0＜r2＜2, p1+q1+r2=2) 등), 또는 리튬-니켈-코발트-전이금속(M) 산화물(예를 들면, Li(Nip2Coq2Mnr3MS2)O2(여기에서, M은 Al, Fe, V, Cr, Ti, Ta, Mg 및 Mo로 이루어지는 군으로부터 선택되고, p2, q2, r3 및 s2는 각각 독립적인 원소들의 원자분율로서, 0＜p2＜1, 0＜q2＜1, 0＜r3＜1, 0＜s2＜1, p2+q2+r3+s2=1이다)) 등을 들 수 있으며, 이들 중 어느 하나 또는 둘 이상의 화합물이 포함될 수 있다. The positive electrode active material is a compound capable of reversible intercalation and deintercalation of lithium, and may specifically include a lithium composite metal oxide containing lithium and one or more metals such as cobalt, manganese, nickel or aluminum. have. More specifically, the lithium composite metal oxide is a lithium-manganese oxide (eg, LiMnO 2 , LiMn 2 O 4, etc.), lithium-cobalt oxide (eg, LiCoO 2, etc.), lithium-nickel oxide (for example, LiNiO 2 and the like), lithium-nickel-manganese-based oxide (for example, LiNi 1-Y Mn Y O 2 (where, 0 <Y <1), LiMn 2-z Ni z O 4 ( here, 0 <Z <2) and the like), lithium-nickel-cobalt oxide (e.g., LiNi 1-Y1 Co Y1 O 2 (here, 0 <Y1 <1) and the like), lithium-manganese-cobalt oxide (e. g., LiCo 1-Y2 Mn Y2 O 2 (here, 0 <Y2 <1), LiMn 2 - z1 Co z1 O 4 ( here, 0 <z1 <2) and the like), lithium-nickel Manganese-cobalt-based oxides (e.g., Li (Ni p Co q Mn r1 ) O 2 , where 0 <p <1, 0 <q <1, 0 <r1 <1, p + q + r1 = 1) or Li (Ni p1 Co q1 Mn r2 ) O 4 (where 0 <p1 <2, 0 <q1 <2, 0 <r2 <2, p1 + q1 + r2 = 2, etc.), or lithium- Nickel-cobalt-transition metal (M) oxide (e.g. Li (Ni p2 Co q2 Mn r3 M S2 ) O 2 (excitation Where M is selected from the group consisting of Al, Fe, V, Cr, Ti, Ta, Mg and Mo, and p2, q2, r3 and s2 are atomic fractions of the independent elements, respectively, 0 <p2 <1, 0 <Q2 <1, 0 <r3 <1, 0 <s2 <1, p2 + q2 + r3 + s2 = 1)), and any one or two or more of these compounds may be included.
이 중에서도 전지의 용량 특성 및 안정성을 높일 수 있다는 점에서 상기 리튬 복합금속 산화물은 LiCoO2, LiMnO2, LiNiO2, 리튬 니켈망간코발트 산화물 (예를 들면 Li(Ni1/3Mn1/3Co1/3)O2, Li(Ni0.6Mn0.2Co0.2)O2, Li(Ni0.5Mn0.3Co0.2)O2, Li(Ni0.7Mn0.15Co0.15)O2 및 Li(Ni0.8Mn0.1Co0.1)O2 등), 또는 리튬 니켈코발트알루미늄 산화물(예를 들면, Li(Ni0.8Co0.15Al0.05)O2 등) 등일 수 있다.Among them, the lithium composite metal oxide may be LiCoO 2 , LiMnO 2 , LiNiO 2 , or lithium nickel manganese cobalt oxide (for example, Li (Ni 1/3 Mn 1/3 Co 1). / 3) O 2, Li ( Ni 0.6 Mn 0.2 Co 0.2) O 2, Li (Ni 0.5 Mn 0.3 Co 0.2 ) O 2 , Li (Ni 0.7 Mn 0.15 Co 0.15 ) O 2, and Li (Ni 0.8 Mn 0.1 Co 0.1 ) O 2 , or the like, or lithium nickel cobalt aluminum oxide (eg, Li (Ni 0.8 Co 0.15 Al 0.05 ) O 2 , and the like.
상기 양극 활물질은 양극 활물질 슬러리 중 고형분의 전체 중량을 기준으로 80 중량% 내지 99 중량%, 구체적으로 85 중량% 내지 95 중량%로 포함될 수 있다.The cathode active material may be included in an amount of 80 wt% to 99 wt%, specifically 85 wt% to 95 wt%, based on the total weight of solids in the cathode active material slurry.
이때, 양극 활물질의 함량이 80 중량% 이하인 경우 에너지 밀도가 낮아져 용량이 저하될 수 있다.At this time, when the content of the positive electrode active material is 80% by weight or less, the energy density is lowered and thus the capacity may be lowered.
상기 바인더는 활물질과 도전재 등의 결합과 집전체에 대한 결합에 조력하는 성분으로서, 통상적으로 양극 활물질 슬러리 중 고형분의 전체 중량을 기준으로 1 중량% 내지 30 중량%로 첨가된다. 이러한 바인더의 예로는, 폴리비닐리덴플루오라이드(PVDF), 폴리비닐알코올, 카르복시메틸셀룰로우즈(CMC), 전분, 히드록시프로필셀룰로우즈, 재생 셀룰로우즈, 폴리비닐피롤리돈, 테트라플루오로에틸렌, 폴리에틸렌, 폴리프로필렌, 에틸렌-프로필렌-디엔 테르 폴리머(EPDM), 술폰화 EPDM, 스티렌-부타디엔 고무, 불소 고무, 다양한 공중합체 등을 들 수 있다.The binder is a component that assists in bonding the active material and the conductive material and bonding to the current collector, and is generally added in an amount of 1 wt% to 30 wt% based on the total weight of solids in the cathode active material slurry. Examples of such binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoro Low ethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluorine rubber, various copolymers, and the like.
이러한 도전재는 당해 전지에 화학적 변화를 유발하지 않으면서 도전성을 가진 것이라면 특별히 제한되는 것은 아니며, 예를 들어, 카본블랙, 아세틸렌 블랙, 케첸 블랙, 채널 블랙, 퍼니스 블랙, 램프 블랙, 또는 서멀 블랙 등의 탄소 분말; 결정구조가 매우 발달된 천연 흑연, 인조흑연, 또는 그라파이트 등의 흑연 분말; 탄소 섬유나 금속 섬유 등의 도전성 섬유; 불화 카본, 알루미늄, 니켈 분말 등의 금속 분말; 산화아연, 티탄산 칼륨 등의 도전성 위스키; 산화티탄 등의 도전성 금속 산화물; 폴리페닐렌 유도체 등의 도전성 소재 등이 사용될 수 있다. The conductive material is not particularly limited as long as it has conductivity without causing chemical change in the battery. For example, carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, or thermal black may be used. Carbon powder; Graphite powders such as natural graphite, artificial graphite, or graphite with very advanced crystal structure; Conductive fibers such as carbon fibers and metal fibers; Metal powders such as carbon fluoride powder, aluminum powder and nickel powder; Conductive whiskeys such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.
상기 도전재는 통상적으로 양극 활물질 슬러리 중 고형분의 전체 중량을 기준으로 1 중량% 내지 30 중량%로 첨가된다. The conductive material is typically added in an amount of 1 wt% to 30 wt% based on the total weight of solids in the cathode active material slurry.
상기 도전재는 아세틸렌 블랙 계열인 쉐브론 케미칼 컴퍼니(Chevron Chemical Company)나 덴카 블랙(Denka Singapore Private Limited), 걸프 오일 컴퍼니(Gulf Oil Company) 제품 등), 케첸 블랙(Ketjenblack), EC 계열(아르막 컴퍼니(Armak Company) 제품), 불칸(Vulcan) XC-72(캐보트 컴퍼니(Cabot Company) 제품) 및 수퍼(Super) P(Timcal 사 제품) 등의 명칭으로 시판되고 있는 것을 사용할 수도 있다.The conductive material is Chevron Chemical Company, Denka Singapore Private Limited, Gulf Oil Company, etc., Ketjenblack, EC series (Armak Company) Armak Company), Vulcan XC-72 (Cabot Company), and Super P (manufactured by Timcal) can also be used.
상기 용매는 NMP(N-methyl-2-pyrrolidone) 등의 유기용매를 포함할 수 있으며, 상기 양극 활물질 및 선택적으로 바인더 및 도전재 등을 포함할 때 바람직한 점도가 되는 양으로 사용될 수 있다. 예를 들면, 양극 활물질, 및 선택적으로 바인더 및 도전재를 포함하는 슬러리 중의 고형분 농도가 10 중량% 내지 70 중량%, 바람직하게 20 중량% 내지 60 중량%가 되도록 포함될 수 있다.The solvent may include an organic solvent such as N-methyl-2-pyrrolidone (NMP), and may be used in an amount that becomes a desirable viscosity when including the positive electrode active material and optionally a binder and a conductive material. For example, the concentration of the solids in the positive electrode active material and, optionally, the slurry including the binder and the conductive material may be 10 wt% to 70 wt%, preferably 20 wt% to 60 wt%.
또한, 상기 음극은 음극 집전체 상에 음극 합제층을 형성하여 제조할 수 있다. 상기 음극 합제층은 음극 집전체 상에 음극활물질, 바인더, 도전재 및 용매 등을 포함하는 음극 활물질 슬러리를 코팅한 후, 건조 및 압연하여 형성할 수 있다.In addition, the negative electrode may be prepared by forming a negative electrode mixture layer on the negative electrode current collector. The negative electrode mixture layer may be formed by coating a negative electrode active material slurry including a negative electrode active material, a binder, a conductive material, a solvent, and the like on a negative electrode current collector, followed by drying and rolling.
상기 음극 집전체는 일반적으로 3 내지 500㎛의 두께를 가진다. 이러한 음극 집전체는, 당해 전지에 화학적 변화를 유발하지 않으면서 높은 도전성을 가지는 것이라면 특별히 제한되는 것은 아니며, 예를 들어, 구리, 스테인리스 스틸, 알루미늄, 니켈, 티탄, 소성 탄소, 구리나 스테인리스 스틸의 표면에 카본, 니켈, 티탄, 은 등으로 표면 처리한 것, 알루미늄-카드뮴 합금 등이 사용될 수 있다. 또한, 양극 집전체와 마찬가지로, 표면에 미세한 요철을 형성하여 음극 활물질의 결합력을 강화시킬 수도 있으며, 필름, 시트, 호일, 네트, 다공질체, 발포체, 부직포체 등 다양한 형태로 사용될 수 있다.The negative electrode current collector generally has a thickness of 3 to 500 μm. Such a negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery. For example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel Surface-treated with carbon, nickel, titanium, silver, and the like on the surface, aluminum-cadmium alloy and the like can be used. In addition, like the positive electrode current collector, fine concavities and convexities may be formed on the surface to enhance the bonding strength of the negative electrode active material, and may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric.
또한, 상기 음극활물질은 리튬 금속, 리튬 이온을 가역적으로 인터칼레이션/디인터칼레이션할 수 있는 탄소 물질, 금속 또는 이들 금속과 리튬의 합금, 금속 복합 산화물, 리튬을 도프 및 탈도프할 수 있는 물질, 및 전이 금속 산화물 전이 금속 산화물로 이루어진 군으로부터 선택된 적어도 하나 이상을 포함할 수 있다. In addition, the negative electrode active material may be lithium metal, a carbon material capable of reversibly intercalating / deintercalating lithium ions, a metal or an alloy of these metals and lithium, a metal complex oxide, and may dope and undo lithium. At least one selected from the group consisting of materials, and transition metal oxide transition metal oxides.
상기 리튬 이온을 가역적으로 인터칼레이션/디인터칼레이션할 수 있는 탄소 물질로는, 리튬 이온 이차전지에서 일반적으로 사용되는 탄소계 음극 활물질이라면 특별히 제한 없이 사용할 수 있으며, 그 대표적인 예로는 결정질 탄소, 비정질 탄소 또는 이들을 함께 사용할 수 있다. 상기 결정질 탄소의 예로는 무정형, 판상, 인편상(flake), 구형 또는 섬유형의 천연 흑연 또는 인조 흑연과 같은 흑연을 들 수 있고, 상기 비정질 탄소의 예로는 소프트 카본(soft carbon: 저온 소성 탄소) 또는 하드 카본(hard carbon), 메조페이스 피치 탄화물, 소성된 코크스 등을 들 수 있다.As the carbon material capable of reversibly intercalating / deintercalating the lithium ions, any carbon-based negative electrode active material generally used in a lithium ion secondary battery may be used without particular limitation. Examples thereof include crystalline carbon, Amorphous carbons or these may be used together. Examples of the crystalline carbon include graphite such as amorphous, plate, flake, spherical or fibrous natural graphite or artificial graphite, and examples of the amorphous carbon include soft carbon (soft carbon) Or hard carbon, mesophase pitch carbide, calcined coke, or the like.
상기 금속 또는 이들 금속과 리튬의 합금으로는 Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al 및 Sn으로 이루어진 군에서 선택되는 금속 또는 이들 금속과 리튬의 합금이 사용될 수 있다.The metals or alloys of these metals with lithium include Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al And a metal selected from the group consisting of Sn or an alloy of these metals with lithium may be used.
상기 금속 복합 산화물로는 PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, Bi2O5, LixFe2O3(0≤x≤1), Lix8WO2(0≤x8≤1), 및 SnxMe1 -xMe'yOz (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, 주기율표의 1족, 2족, 3족 원소, 할로겐; 0<x≤1; 1≤y≤3; 1≤z≤8) 로 이루어진 군에서 선택되는 것이 사용될 수 있다.The metal complex oxide may include PbO, PbO 2 , Pb 2 O 3 , Pb 3 O 4 , Sb 2 O 3 , Sb 2 O 4 , Sb 2 O 5 , GeO, GeO 2 , Bi 2 O 3 , Bi 2 O 4 , Bi 2 O 5 , Li x Fe 2 O 3 (0 ≦ x ≦ 1), Li x8 WO 2 (0 ≦ x8 ≦ 1), and Sn x Me 1- x Me ' y O z (Me: Mn, Fe Me ': Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, halogen; 0 <x≤1;1≤y≤3; 1≤z≤8 Any one selected from the group can be used.
상기 리튬을 도프 및 탈도프할 수 있는 물질로는 Si, SiOx7(0<x7<2), Si-Y 합금(상기 Y는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Si은 아님), Sn, SnO2, Sn-Y(상기 Y는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Sn은 아님) 등을 들 수 있고, 또한 이들 중 적어도 하나와 SiO2를 혼합하여 사용할 수도 있다. 상기 원소 Y로는 Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Bi, S, Se, Te, Po, 및 이들의 조합으로 이루어진 군에서 선택될 수 있다.Examples of materials capable of doping and undoping lithium include Si, SiO x7 (0 <x7 <2), Si-Y alloys (wherein Y is an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, a transition metal, Is an element selected from the group consisting of rare earth elements and combinations thereof, not Si), Sn, SnO 2 , Sn-Y (Y is an alkali metal, alkaline earth metal, group 13 element, group 14 element, transition metal, rare earth) An element selected from the group consisting of elements and combinations thereof, and not Sn; and at least one of these and SiO 2 may be mixed and used. As the element Y, Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Bi, S, Se, Te, Po, and combinations thereof.
상기 전이 금속 산화물로는 리튬 함유 티타늄 복합 산화물(LTO), 바나듐 산화물, 리튬 바나듐 산화물 등을 들 수 있다.Examples of the transition metal oxide include lithium-containing titanium composite oxide (LTO), vanadium oxide, lithium vanadium oxide, and the like.
상기 음극 활물질은 음극 활물질 슬러리 중 고형분의 전체 중량을 기준으로 80 중량% 내지 99 중량%로 포함될 수 있다.The negative active material may be included in an amount of 80 wt% to 99 wt% based on the total weight of solids in the negative electrode active material slurry.
상기 바인더는 도전재, 활물질 및 집전체 간의 결합에 조력하는 성분으로서, 통상적으로 음극 활물질 슬러리 중 고형분의 전체 중량을 기준으로 1 중량% 내지 30 중량%로 첨가된다.　이러한 바인더의 예로는, 폴리비닐리덴플루오라이드(PVDF), 폴리비닐알코올, 카르복시메틸셀룰로우즈(CMC), 전분, 히드록시프로필셀룰로우즈, 재생 셀룰로우즈, 폴리비닐피롤리돈, 테트라플루오로에틸렌, 폴리에틸렌, 폴리프로필렌, 에틸렌-프로필렌-디엔 폴리머(EPDM), 술폰화-EPDM, 스티렌-부타디엔 고무, 불소 고무, 이들의 다양한 공중합체 등을 들 수 있다.The binder is a component that assists the bonding between the conductive material, the active material and the current collector, and is typically added in an amount of 1% by weight to 30% by weight based on the total weight of solids in the negative electrode active material slurry. Examples of such binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoro Low ethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, fluorine rubber, various copolymers thereof, and the like.
상기 도전재는 음극 활물질의 도전성을 더욱 향상시키기 위한 성분으로서, 음극 활물질 슬러리 중 고형분의 전체 중량을 기준으로 1 중량% 내지 20 중량%로 첨가될 수 있다.　이러한 도전재는 당해 전지에 화학적 변화를 유발하지 않으면서 도전성을 가진 것이라면 특별히 제한되는 것은 아니며, 예를 들어, 카본블랙, 아세틸렌 블랙, 케첸 블랙, 채널 블랙, 퍼니스 블랙, 램프 블랙, 또는 서멀 블랙 등의 탄소 분말; 결정구조가 매우 발달된 천연 흑연, 인조흑연, 또는 그라파이트 등의 흑연 분말; 탄소 섬유나 금속 섬유 등의 도전성 섬유; 불화 카본, 알루미늄, 니켈 분말 등의 금속 분말; 산화아연, 티탄산 칼륨 등의 도전성 위스키; 산화티탄 등의 도전성 금속 산화물; 폴리페닐렌 유도체 등의 도전성 소재 등이 사용될 수 있다. The conductive material is a component for further improving the conductivity of the negative electrode active material, and may be added in an amount of 1 wt% to 20 wt% based on the total weight of solids in the negative electrode active material slurry. The conductive material is not particularly limited as long as it has conductivity without causing chemical change in the battery. For example, carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, or thermal black may be used. Carbon powder; Graphite powders such as natural graphite, artificial graphite, or graphite with very advanced crystal structure; Conductive fibers such as carbon fibers and metal fibers; Metal powders such as carbon fluoride powder, aluminum powder and nickel powder; Conductive whiskeys such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.
상기 용매는 물 또는 NMP, 알코올 등의 유기용매를 포함할 수 있으며, 상기 음극 활물질 및 선택적으로 바인더 및 도전재 등을 포함할 때 바람직한 점도가 되는 양으로 사용될 수 있다. 예를 들면, 음극 활물질, 및 선택적으로 바인더 및 도전재를 포함하는 슬러리 중의 고형분 농도가 50 중량% 내지 75 중량%, 바람직하게 50 중량% 내지 65 중량%가 되도록 포함될 수 있다.The solvent may include an organic solvent such as water or NMP, alcohol, etc., and may be used in an amount that becomes a desirable viscosity when including the negative electrode active material and optionally a binder and a conductive material. For example, the concentration of the solids in the slurry including the negative electrode active material and, optionally, the binder and the conductive material may be 50 wt% to 75 wt%, preferably 50 wt% to 65 wt%.
또한, 상기 분리막은 양 전극의 내부 단락을 차단하고 전해질을 함침하는 역할을 하는 것으로, 고분자 수지, 충진제 및 용매를 혼합하여 분리막 조성물을 제조한 다음, 상기 분리막 조성물을 전극 상부에 직접 코팅 및 건조하여 분리막 필름을 형성하거나, 상기 분리막 조성물을 지지체 상에 캐스팅 및 건조된 후, 상기 지지체로부터 박리된 분리막 필름을 전극 상부에 라미네이션하여 형성할 수 있다. In addition, the separator serves to block internal short circuits of both electrodes and to impregnate the electrolyte, to prepare a separator composition by mixing a polymer resin, a filler, and a solvent, and then directly coating and drying the separator composition on the electrode. After forming the separator film or casting and drying the separator composition on the support, the separator film separated from the support may be formed by lamination on the electrode.
상기 분리막은 통상적으로 사용되는 다공성 고분자 필름, 예를 들어 에틸렌 단독중합체, 프로필렌 단독중합체, 에틸렌/부텐 공중합체, 에틸렌/헥센 공중합체 및 에틸렌/메타크릴레이트 공중합체 등과 같은 폴리올레핀계 고분자로 제조한 다공성 고분자 필름을 단독으로 또는 이들을 적층하여 사용할 수 있으며, 또는 통상적인 다공성 부직포, 예를 들어 고융점의 유리 섬유, 폴리에틸렌테레프탈레이트 섬유 등으로 된 부직포를 사용할 수 있으나, 이에 한정되는 것은 아니다.The separator is a porous polymer film commonly used, for example, a porous polymer made of a polyolefin-based polymer such as ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer and ethylene / methacrylate copolymer The polymer film may be used alone or in a stack thereof, or a conventional porous nonwoven fabric, for example, a non-woven fabric made of high melting point glass fiber, polyethylene terephthalate fiber, or the like may be used, but is not limited thereto.
이때, 상기 다공성 분리막의 기공 직경은 일반적으로 0.01 내지 50㎛이고, 기공도는 5% 내지 95%일 수 있다. 또한, 상기 다공성 분리막의 두께는 일반적으로 5 내지 300㎛ 범위일 수 있다. In this case, the pore diameter of the porous separator is generally 0.01 to 50㎛, porosity may be 5% to 95%. In addition, the thickness of the porous separator may generally range from 5 to 300㎛.
본 발명의 리튬 이차전지의 외형은 특별한 제한이 없으나, 캔을 사용한 원통형, 각형, 파우치(pouch)형 또는 코인(coin)형 등이 될 수 있다.The external shape of the lithium secondary battery of the present invention is not particularly limited, but may be cylindrical, square, pouch type, or coin type using a can.
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 안 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 many different 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.
실시예Example
I. 액체 전해질을 포함하는 리튬 이차전지I. Lithium Secondary Battery Containing Liquid Electrolyte
실시예Example 1 One
(액체 전해질 제조)(Liquid Electrolyte Preparation)
1M LiPF6가 용해된 비수성 유기용매 (에틸렌 카보네이트 (EC):에틸메틸카보네이트 (EMC)=3:7(부피%)) 95g에 상기 화학식 1a-1의 화합물 (n2=55, 중량평균분자량(Mw): 5,000) 5g을 첨가하여 액체 전해질을 제조하였다 (하기 표 1 참조).95 g of a non-aqueous organic solvent (ethylene carbonate (EC): ethyl methyl carbonate (EMC) = 3: 7 (vol%)) in which 1M LiPF 6 was dissolved (n2 = 55, weight average molecular weight (1) Mw): 5,000) 5 g was added to prepare a liquid electrolyte (see Table 1 below).
(이차전지 제조)(Secondary Battery Manufacturing)
양극 활물질로 (LiNi1 / 3Co1 / 3Mn1 / 3O2; NCM) 94 중량%, 도전재로 카본 블랙(carbon black) 3 중량%, 바인더로 폴리비닐리덴플루오라이드 3 중량%를 용매인 N-메틸-2-피롤리돈(NMP)에 첨가하여 양극 활물질 슬러리 (고형분 함량 50 중량%)를 제조하였다. 상기 양극 활물질 슬러리를 두께가 20㎛의 양극 집전체인 알루미늄(Al) 박막에 도포하고, 건조하여 양극을 제조한 후, 롤 프레스(roll press)를 실시하여 양극을 제조하였다.As a cathode active material (LiNi 1/3 Co 1/ 3 Mn 1/3 O 2; NCM) 94 % by weight, of a conductive material of carbon black (carbon black) 3% by weight, a solvent for polyvinylidene fluoride, 3 weight% of a binder Phosphorus N-methyl-2-pyrrolidone (NMP) was added to prepare a positive electrode active material slurry (50% by weight solid content). The positive electrode active material slurry was applied to a thin film of aluminum (Al), which is a positive electrode current collector having a thickness of 20 μm, and dried to prepare a positive electrode, followed by a roll press to prepare a positive electrode.
음극 활물질로 탄소 분말, 바인더로 PVDF, 도전재로 카본 블랙(carbon black)을 각각 96 중량%, 3 중량% 및 1 중량%로 하여 용매인 NMP에 첨가하여 음극 활물질 슬러리 (고형분 함량 65 중량%)를 제조하였다. 상기 음극 활물질 슬러리를 두께가 10㎛의 음극 집전체인 구리(Cu) 박막에 도포하고, 건조하여 음극을 제조한 후, 롤 프레스(roll press)를 실시하여 음극을 제조하였다.Negative active material slurry (65 wt% solids) by adding carbon powder as a negative electrode active material, PVDF as a binder and carbon black as a conductive material at 96 wt%, 3 wt% and 1 wt%, respectively, to NMP as a solvent. Was prepared. The negative electrode active material slurry was applied to a copper (Cu) thin film, which is a negative electrode current collector having a thickness of 10 μm, and dried to prepare a negative electrode, followed by roll press, to prepare a negative electrode.
상기 제조된 양극, 음극 및 폴리프로필렌/폴리에틸렌/폴리프로필렌 (PP/PE/PP) 3층으로 이루어진 분리막을 순차적으로 적층하여 전극조립체를 제조한 다음, 전지 케이스 내에 상기 조립된 전극조립체를 수납하고, 상기 액체 전해질을 주액하여 리튬 이차전지를 제조하였다.The electrode assembly was prepared by sequentially stacking the separator consisting of the prepared positive electrode, the negative electrode, and three layers of polypropylene / polyethylene / polypropylene (PP / PE / PP), and then storing the assembled electrode assembly in a battery case. The lithium secondary battery was manufactured by pouring the liquid electrolyte.
실시예 2Example 2
상기 실시예 1의 액체 전해질 제조 시에, 상기 비수성 유기용매 80g에 화학식 1a-1의 화합물 (n2=55, 중량평균분자량(Mw): 5,000) 20g을 포함하는 것을 제외하고는, 상기 실시예 1과 마찬가지의 방법으로 액체 전해질 및 이를 포함하는 이차전지를 제조하였다(하기 표 1 참조).In preparing the liquid electrolyte of Example 1, except that 80 g of the non-aqueous organic solvent included 20 g of a compound of Formula 1a-1 (n2 = 55, weight average molecular weight (Mw): 5,000), In the same manner as in 1, a liquid electrolyte and a secondary battery including the same were prepared (see Table 1 below).
실시예 3Example 3
상기 실시예 1의 액체 전해질 제조 시에, 상기 비수성 유기용매 99.7g에 화학식 1a-1의 화합물 (n2=55, 중량평균분자량(Mw): 5,000) 0.3g을 포함하는 것을 제외하고는, 상기 실시예 1과 마찬가지의 방법으로 액체 전해질 및 이를 포함하는 이차전지를 제조하였다 (하기 표 1 참조).In preparing the liquid electrolyte of Example 1, except that 99.7 g of the non-aqueous organic solvent included 0.3 g of a compound of Formula 1a-1 (n2 = 55, weight average molecular weight (Mw): 5,000) In the same manner as in Example 1, a liquid electrolyte and a secondary battery including the same were prepared (see Table 1 below).
실시예 4Example 4
상기 실시예 1의 액체 전해질 제조 시에, 상기 비수성 유기용매 70g에 화학식 1a-1의 화합물 (n2=55, 중량평균분자량(Mw): 5,000) 30g을 포함하는 것을 제외하고는, 상기 실시예 1과 마찬가지의 방법으로 액체 전해질 및 이를 포함하는 이차전지를 제조하였다 (하기 표 1 참조).In preparing the liquid electrolyte of Example 1, except that 70 g of the non-aqueous organic solvent included 30 g of a compound of Formula 1a-1 (n2 = 55, weight average molecular weight (Mw): 5,000), In the same manner as in 1, a liquid electrolyte and a secondary battery including the same were prepared (see Table 1 below).
비교예 1.Comparative Example 1.
상기 실시예 1의 액체 전해질 제조 시에, 화학식 1a-1의 화합물을 포함하지 않는 것을 제외하고는, 상기 실시예 1과 마찬가지의 방법으로 액체 전해질 및 이를 포함하는 이차전지를 제조하였다 (하기 표 1 참조).In preparing the liquid electrolyte of Example 1, except that the compound of Formula 1a-1 is not included, a liquid electrolyte and a secondary battery including the same were prepared in the same manner as in Example 1 (Table 1 below). Reference).
비교예 2Comparative Example 2
상기 실시예 1의 액체 전해질 제조 시에, 화학식 1a-1의 화합물을 포함하지 않고, 1M LiFSI를 비수성 유기용매 (EC:PC:DEC=3:2:5 부피%)를 사용하는 것을 제외하고는, 상기 실시예 1과 마찬가지의 방법으로 액체 전해질 및 이를 포함하는 이차전지를 제조하였다 (하기 표 1 참조).In preparing the liquid electrolyte of Example 1, except that the compound of Formula 1a-1 is not included and 1M LiFSI is used as a non-aqueous organic solvent (EC: PC: DEC = 3: 2: 5% by volume). In the same manner as in Example 1, a liquid electrolyte and a secondary battery including the same were prepared (see Table 1 below).
II. 겔 폴리머 전해질을 포함하는 리튬 이차전지II. Lithium Secondary Battery Containing Gel Polymer Electrolyte
실시예 5Example 5
(겔 폴리머 전해질용 조성물 제조)(Manufacture of composition for gel polymer electrolyte)
1M LiPF6가 용해된 비수성 유기용매 (에틸렌 카보네이트 (EC):에틸메틸카보네이트 (EMC) = 3:7(부피비)) 93.5g에 상기 화학식 1a-1의 올리고머 (n2=55, 중량평균 분자량(MW): 5,000) 5g, 중합개시제인 2,2'-아조비스(이소부티로니트릴) 0.5g 및 비닐렌카보네이트(VC) 1g를 첨가하여 겔 폴리머 전해질용 조성물을 제조하였다 (하기 표 1 참조). To 93.5 g of a non-aqueous organic solvent (ethylene carbonate (EC): ethyl methyl carbonate (EMC) = 3: 7 (volume ratio)) in which 1M LiPF 6 was dissolved, an oligomer of Formula 1a-1 (n2 = 55, weight average molecular weight ( MW): 5,000) 5g, 2,2'-azobis (isobutyronitrile), a polymerization initiator, 0.5g and 1g of vinylene carbonate (VC) were added to prepare a composition for a gel polymer electrolyte (see Table 1 below). .
(이차전지 제조)(Secondary Battery Manufacturing)
양극 활물질로 (LiNi1 / 3Co1 / 3Mn1 / 3O2; NCM) 94 중량%, 도전재로 카본 블랙(carbon black) 3 중량%, 바인더로 폴리비닐리덴플루오라이드 3 중량%를 용매인 N-메틸-2-피롤리돈(NMP)에 첨가하여 양극 활물질 슬러리 (고형분 함량 50 중량%)를 제조하였다. 상기 양극 활물질 슬러리를 두께가 20㎛의 양극 집전체인 알루미늄(Al) 박막에 도포하고, 건조하여 양극을 제조한 후, 롤 프레스(roll press)를 실시하여 양극을 제조하였다.As a cathode active material (LiNi 1/3 Co 1/ 3 Mn 1/3 O 2; NCM) 94 % by weight, of a conductive material of carbon black (carbon black) 3% by weight, a solvent for polyvinylidene fluoride, 3 weight% of a binder Phosphorus N-methyl-2-pyrrolidone (NMP) was added to prepare a positive electrode active material slurry (50% by weight solid content). The positive electrode active material slurry was applied to a thin film of aluminum (Al), which is a positive electrode current collector having a thickness of 20 μm, and dried to prepare a positive electrode, followed by a roll press to prepare a positive electrode.
음극 활물질로 탄소 분말, 바인더로 PVDF, 도전재로 카본 블랙(carbon black)을 각각 96 중량%, 3 중량% 및 1 중량%로 하여 용매인 NMP에 첨가하여 음극 활물질 슬러리 (고형분 함량 65 중량%)를 제조하였다. 상기 음극 ?W루질 슬러리를 두께가 10㎛의 음극 집전체인 구리(Cu) 박막에 도포하고, 건조하여 음극을 제조한 후, 롤 프레스(roll press)를 실시하여 음극을 제조하였다.Negative active material slurry (65 wt% solids) by adding carbon powder as a negative electrode active material, PVDF as a binder and carbon black as a conductive material at 96 wt%, 3 wt% and 1 wt%, respectively, to NMP as a solvent. Was prepared. The negative electrode W rutile slurry was applied to a thin copper (Cu) thin film which is a negative electrode current collector having a thickness of 10 μm, dried to prepare a negative electrode, and then roll-rolled to prepare a negative electrode.
상기 제조된 양극, 음극 및 폴리프로필렌/폴리에틸렌/폴리프로필렌 (PP/PE/PP) 3층으로 이루어진 분리막을 순차적으로 적층하여 전극조립체를 제조한 다음, 전지 케이스 내에 상기 조립된 전극조립체를 수납하고, 상기 겔 폴리머 전해질용 조성물을 주액한 후 2일 동안 에이징(aging)하였다. 이후, 이를 70℃에서 5시간 경화(curing)하여 열중합된 겔 폴리머 전해질을 포함하는 리튬 이차전지를 얻었다.The electrode assembly was prepared by sequentially stacking the separator consisting of the prepared positive electrode, the negative electrode, and three layers of polypropylene / polyethylene / polypropylene (PP / PE / PP), and then storing the assembled electrode assembly in a battery case. The gel polymer electrolyte composition was infused and then aged for 2 days. Thereafter, this was cured at 70 ° C. for 5 hours to obtain a lithium secondary battery including a gel polymer electrolyte thermally polymerized.
실시예Example 6. 6.
상기 실시예 5의 겔 폴리머 전해질용 조성물 제조 시에, 1M LiFSI가 용해된 비수성 유기용매 (EC:PC:DEC=3:2:5 부피%) 98.67g에 상기 화학식 1a-1로 표시되는 올리고머(n2=55, 중량평균 분자량(MW): 5,000) 0.3g 및 중합개시제 0.03g을 사용한 것을 제외하고, 상기 실시예 5와 동일한 방법으로 겔 폴리머 전해질용 조성물 및 이를 이용한 리튬 이차전지를 제조하였다 (하기 표 1 참조).In preparing the gel polymer electrolyte composition of Example 5, the oligomer represented by Chemical Formula 1a-1 in 98.67 g of a non-aqueous organic solvent (EC: PC: DEC = 3: 2: 5% by volume) in which 1M LiFSI was dissolved (n2 = 55, weight average molecular weight (MW): 5,000) A gel polymer electrolyte composition and a lithium secondary battery using the same were manufactured in the same manner as in Example 5, except that 0.3 g and 0.03 g of a polymerization initiator were used ( See Table 1 below).
실시예Example 7. 7.
상기 실시예 5의 겔 폴리머 전해질용 조성물 제조 시에, 상기 비수성 유기용매 77g에 상기 화학식 1a-1로 표시되는 올리고머(n2=55, 중량평균 분자량(MW): 5,000) 20g 및 중합개시제 2g을 사용한 것을 제외하고, 상기 실시예 5와 동일한 방법으로 겔 폴리머 전해질용 조성물 및 이를 이용한 리튬 이차전지를 제조하였다 (하기 표 1 참조).In preparing the gel polymer electrolyte composition of Example 5, 20 g of an oligomer (n2 = 55, weight average molecular weight (MW): 5,000) represented by Chemical Formula 1a-1 was added to 77 g of the non-aqueous organic solvent, and 2 g of a polymerization initiator. Except for the use, a composition for a gel polymer electrolyte and a lithium secondary battery using the same were prepared in the same manner as in Example 5 (see Table 1 below).
실시예Example 8. 8.
상기 실시예 5의 겔 폴리머 전해질용 조성물 제조 시에, 상기 비수성 유기용매 98.67g에 상기 화학식 1a-1로 표시되는 올리고머 0.3g 및 중합개시제 0.03g을 사용한 것을 제외하고, 상기 실시예 5와 동일한 방법으로 겔 폴리머 전해질용 조성물 및 이를 이용한 리튬 이차전지를 제조하였다 (하기 표 1 참조).In preparing the gel polymer electrolyte composition of Example 5, the same procedure as in Example 5 was performed except that 0.3g of the oligomer represented by Chemical Formula 1a-1 and 0.03g of a polymerization initiator were used in 98.67g of the non-aqueous organic solvent. By the method, a gel polymer electrolyte composition and a lithium secondary battery using the same were prepared (see Table 1 below).
실시예Example 9. 9.
상기 실시예 5의 겔 폴리머 전해질용 조성물 제조 시에, 상기 비수성 유기용매 66g에 상기 화학식 1a-1로 표시되는 올리고머(n2=55, 중량평균 분자량(MW): 5,000) 30g 및 중합개시제 3g을 사용한 것을 제외하고, 상기 실시예 5와 동일한 방법으로 겔 폴리머 전해질용 조성물 및 이를 이용한 리튬 이차전지를 제조하였다 (하기 표 1 참조).In preparing the gel polymer electrolyte composition of Example 5, 30 g of an oligomer (n2 = 55, weight average molecular weight (MW): 5,000) represented by Chemical Formula 1a-1 and 3 g of a polymerization initiator were added to 66 g of the non-aqueous organic solvent. Except for the use, a composition for a gel polymer electrolyte and a lithium secondary battery using the same were prepared in the same manner as in Example 5 (see Table 1 below).
실시예Example 10. 10.
상기 실시예 5의 겔 폴리머 전해질용 조성물의 제조에서, 유기용매 사용량을 83.5g으로 하고, 무기물 입자(TiO2) 10g을 더 포함하는 것을 제외하고는, 상기 실시예 5와 동일한 방법으로 겔 폴리머 전해질용 조성물 및 이를 이용한 리튬 이차전지를 제조하였다 (하기 표 1 참조).In the preparation of the composition for a gel polymer electrolyte of Example 5, the amount of the organic solvent is 83.5 g, and the gel polymer electrolyte is the same as in Example 5, except that 10 g of the inorganic particles (TiO 2 ) is further included. The composition and a lithium secondary battery using the same were prepared (see Table 1 below).
비교예Comparative example 3. 3.
상기 실시예 5의 겔 폴리머 전해질용 조성물 제조 시에, 올리고머로 상기 화학식 1a-1의 올리고머 대신 하기 화학식 2의 화합물을 포함하는 것을 제외하고는, 상기 실시예 5와 동일한 방법으로 겔 폴리머 전해질용 조성물 및 이를 이용한 리튬 이차전지를 제조하였다 (하기 표 1 참조).In the preparation of the gel polymer electrolyte composition of Example 5, the composition for gel polymer electrolyte in the same manner as in Example 5, except that the compound of the formula (2) instead of the oligomer of Formula 1a-1 as an oligomer And a lithium secondary battery using the same (see Table 1 below).
[화학식 2][Formula 2]
Figure PCTKR2017014432-appb-I000007
Figure PCTKR2017014432-appb-I000007
Figure PCTKR2017014432-appb-T000001
Figure PCTKR2017014432-appb-T000001
실험예Experimental Example
실험예Experimental Example 1: 고온 저장 안정성 평가 실험 1: High Temperature Storage Stability Evaluation Experiment
상기 실시예 1 내지 4에서 제조된 액체 전해질을 포함하는 리튬 이차전지와 비교예 1 및 2에서 제조된 액체 전해질을 포함하는 리튬 이차전지를 각각 0.33C/4.15V 정전류-정전압으로 만충전하고, SOC 50%에서 5C로 10초간 방전하여 초기 충방전을 수행하였다. 초기 충방전 후, 각각 4.15V로 충전하고, 80℃에서 10 주 동안 저장한 (SOC; state of charge) 100) 후, 두께 증가율(%) 및 저항 증가율(%)을 측정하였다. The lithium secondary battery comprising the liquid electrolytes prepared in Examples 1 to 4 and the lithium secondary battery comprising the liquid electrolytes prepared in Comparative Examples 1 and 2 were fully charged at 0.33C / 4.15V constant current-constant voltage, respectively, and the SOC 50 Initial charge and discharge were performed by discharging at 5C for 10 seconds. After initial charging and discharging, each was charged to 4.15V, and stored at 80 ° C. for 10 weeks (SOC; 100 of state), and then the thickness increase rate (%) and the resistance increase rate (%) were measured.
상기 두께 증가율(%) 및 저항 증가율(%)을 하기 표 2에 나타내었다.The thickness increase rate (%) and the resistance increase rate (%) are shown in Table 2 below.
이때, 전지의 두께 증가율 (%) 및 저항 증가율(%)은 하기 식 1 및 2를 이용하여 계산하였다.At this time, the thickness increase rate (%) and the resistance increase rate (%) of the battery were calculated using the following Equations 1 and 2.
[식 1][Equation 1]
전지의 두께 증가율(%) = [(최종두께 - 초기두께) / 초기두께] ×100 (%)Battery thickness increase rate (%) = [(final thickness-initial thickness) / initial thickness] × 100 (%)
[식 2][Equation 2]
전지의 저항 증가율(%) = [(최종저항 - 초기저항) / 초기저항] × 100 (%)% Increase in battery resistance = [(final resistance-initial resistance) / initial resistance] × 100 (%)
또한, 상기와 같은 방법으로 상기 실시예 5 내지 10에서 제조된 겔 폴리머 전해질을 포함하는 리튬 이차전지와 비교예 3에서 제조된 겔 폴리머 전해질을 포함하는 리튬 이차전지에 대한 80℃에서의 두께 증가율(%) 및 저항 증가율(%)을 측정하였다. In addition, the thickness increase rate at 80 ° C. for the lithium secondary battery including the gel polymer electrolytes prepared in Examples 5 to 10 and the lithium secondary battery including the gel polymer electrolytes prepared in Comparative Example 3 ( %) And resistance increase rate (%) were measured.
상기 두께 증가율(%) 및 저항 증가율(%)을 하기 표 2에 나타내었다.The thickness increase rate (%) and the resistance increase rate (%) are shown in Table 2 below.
Figure PCTKR2017014432-appb-T000002
Figure PCTKR2017014432-appb-T000002
상기 표 2를 살펴보면, 본 발명의 화학식 1a-1로 표시되는 올리고머를 포함하는 액체 전해질을 구비한 실시예 1 내지 4의 리튬 이차전지의 경우, 올리고머를 포함하지 않은 액체 전해질을 구비한 비교예 1 및 2의 리튬 이차전지에 비하여 80℃에서 10주 후 두께 증가율(%)이 현저히 낮은 것을 알 수 있다.Looking at Table 2, in the case of the lithium secondary battery of Examples 1 to 4 with a liquid electrolyte containing an oligomer represented by the formula (1a-1) of the present invention, Comparative Example 1 provided with a liquid electrolyte not containing oligomer And it can be seen that the thickness increase rate (%) after 10 weeks at 80 ℃ compared to the lithium secondary battery of 2 is significantly lower.
또한, 본 발명의 화학식 1a-1로 표시되는 올리고머를 포함하는 액체 전해질을 구비한 실시예 1 내지 4의 리튬 이차전지의 경우, 올리고머를 포함하지 않은 액체 전해질을 구비한 비교예 1 및 2의 리튬 이차전지에 비하여 80℃에서 10주 후 저항 증가율(%)이 현저히 감소된 것을 알 수 있다.In addition, in the case of the lithium secondary batteries of Examples 1 to 4 having the liquid electrolyte containing the oligomer represented by the formula (1a-1) of the present invention, the lithium of Comparative Examples 1 and 2 provided with the liquid electrolyte containing no oligomer It can be seen that the resistance increase rate (%) was significantly reduced after 10 weeks at 80 ° C. compared with the secondary battery.
또한, 상기 표 2를 살펴보면, 본 발명의 화학식 1a-1로 표시되는 올리고머 유래 폴리머를 포함하는 겔 폴리머 전해질을 구비한 실시예 5 내지 10의 리튬 이차전지의 경우, 화학식 2의 화합물 유래 폴리머를 포함하는 겔 폴리머 전해질을 구비한 비교예 3의 리튬 이차전지에 비하여 80℃에서 10주 후 두께 증가율(%)이 현저히 낮은 것을 알 수 있다.In addition, referring to Table 2, in the case of the lithium secondary battery of Examples 5 to 10 having the gel polymer electrolyte containing the oligomer-derived polymer represented by the formula (1a-1) of the present invention, the compound of the compound of formula (2) It can be seen that the thickness increase rate (%) after 10 weeks at 80 ° C. is significantly lower than that of the lithium secondary battery of Comparative Example 3 having a gel polymer electrolyte.
또한, 본 발명의 화학식 1a-1로 표시되는 올리고머 유래 폴리머를 포함하는 겔 폴리머 전해질을 구비한 실시예 5 내지 10의 리튬 이차전지의 경우, 화학식 2의 화합물 유래 폴리머를 포함하는 겔 폴리머 전해질을 구비한 비교예 3의 리튬 이차전지에 비하여 80℃에서 10주 후 저항 증가율(%)이 현저히 감소된 것을 알 수 있다.In addition, in the case of the lithium secondary battery of Examples 5 to 10 having the gel polymer electrolyte containing the oligomer-derived polymer represented by the formula (1a-1) of the present invention, the gel polymer electrolyte including the polymer derived from the compound of the formula (2) is provided. Compared with the lithium secondary battery of Comparative Example 3, the resistance increase rate (%) was significantly reduced after 10 weeks at 80 ° C.
실험예 2: 발생가스 함량 측정Experimental Example 2: Measurement of Generated Gas Content
상기 실시예 1에서 제조된 액체 전해질을 포함하는 리튬 이차전지와 비교예 1에서 제조된 액체 전해질을 포함하는 리튬 이차전지를 상기 실험예 1과 동일한 방법으로 충방전 한 후, GC (gas chromatography) 분석 방법을 사용하여 고온 저장 시 전지 내부에서의 발생된 CO 및 CO2 가스 함량을 측정하였다. 그 비교 결과를 하기 도 1에 나타내었다.After charging and discharging the lithium secondary battery including the liquid electrolyte prepared in Example 1 and the lithium secondary battery including the liquid electrolyte prepared in Comparative Example 1 in the same manner as in Experimental Example 1, GC (gas chromatography) analysis The method was used to measure the generated CO and CO 2 gas content inside the cell at high temperature storage. The comparison results are shown in FIG. 1.
도 1에 나타낸 바와 같이, 본 발명의 올리고머를 포함하는 액체 전해질을 구비한 실시예 1의 리튬 이차전지 내부에서 발생한 CO 가스 함량은 약 100 ㎕이었고, CO2 가스 함량은 약 200㎕ 이하인 것을 알 수 있다.As shown in FIG. 1, the amount of CO gas generated in the lithium secondary battery of Example 1 having the liquid electrolyte including the oligomer of the present invention was about 100 μl, and the amount of CO 2 gas was about 200 μl or less. have.
반면에, 올리고머를 포함하지 않는 액체 전해질을 구비한 비교예 1의 이차전지의 경우, 발생된 CO 가스 함량은 약 700 ㎕이고, CO2 가스 함량은 약 500㎕ 정도로, 상기 실시예 1의 이차전지 대비하여 약 6배 이상의 가스가 발생한 것을 알 수 있다. On the other hand, in the case of the secondary battery of Comparative Example 1 having a liquid electrolyte containing no oligomer, the generated CO gas content is about 700 μl, the CO 2 gas content is about 500 μl, the secondary battery of Example 1 In contrast, it can be seen that about 6 times more gas is generated.
이러한 결과로부터, 본 발명의 실시예에 따른 올리고머를 포함하는 액체 전해질의 경우, 우수한 산화 안정성을 보여, 이차전지 내부에서 가스 발생량이 현저히 저감된 것을 알 수 있다.From these results, it can be seen that the liquid electrolyte including the oligomer according to the embodiment of the present invention showed excellent oxidative stability and significantly reduced the amount of gas generated inside the secondary battery.
실험예 3: 발생가스 함량 측정Experimental Example 3: Measurement of Generated Gas Content
실시예 5 및 6에서 제조된 겔 폴리머 전해질을 포함하는 리튬 이차전지와 비교예 3에서 제조된 겔 폴리머 전해질을 포함하는 리튬 이차전지를 상기 실험예 1과 동일한 방법으로 충방전 한 후, GC (gas chromatography) 분석 방법을 사용하여 고온 저장 시 전지 내부에서의 발생된 CO 및 CO2 가스 함량을 측정하였다. 그 비교 결과를 하기 도 2에 나타내었다.After charging and discharging the lithium secondary battery including the gel polymer electrolyte prepared in Examples 5 and 6 and the lithium secondary battery comprising the gel polymer electrolyte prepared in Comparative Example 3 in the same manner as in Experimental Example 1, GC (gas The CO and CO 2 gas contents generated inside the cell during high temperature storage were measured using a chromatographic analysis method. The comparison results are shown in FIG. 2.
도 2에 나타낸 바와 같이, 본 발명의 실시예에 따른 올리고머 유래 폴리머를 포함하는 겔 폴리머 전해질을 구비한 실시예 5 및 6의 리튬 이차전지 내부에서 발생된 CO 가스 함량은 약 500 ㎕이고, CO2 가스 함량은 약 300㎕ 이하인 것을 알 수 있다.As shown in FIG. 2, the CO gas content generated in the lithium secondary batteries of Examples 5 and 6 including the gel polymer electrolyte including the oligomer-derived polymer according to the embodiment of the present invention is about 500 μl, and CO 2 It can be seen that the gas content is about 300 μl or less.
반면에, 화학식 2의 화합물 유래 폴리머를 포함하는 겔 폴리머 전해질을 구비한 비교예 3의 리튬 이차전지의 경우, 발생된 CO 가스 함량은 약 1000 ㎕이고, CO2 가스 함량은 약 2000㎕ 정도로, 상기 실시예 5 및 6의 이차전지에 비하여 2배 이상의 가스가 발생한 것을 알 수 있다. On the other hand, in the lithium secondary battery of Comparative Example 3 having a gel polymer electrolyte containing a polymer derived from the compound of Formula 2, the generated CO gas content is about 1000 μl, CO 2 gas content is about 2000 μl, It can be seen that more than twice the gas is generated as compared with the secondary batteries of Examples 5 and 6.
즉, 실시예 5 및 6의 이차전지는 비교예 3의 이차전지 대비 CO 가스가 50% 이상 감소하였고, CO2 가스가 약 70% 내지 80% 이상 감소되었음을 알 수 있다.That is, in the secondary batteries of Examples 5 and 6, the CO gas was reduced by 50% or more, and the CO 2 gas was reduced by about 70% to 80% or more compared with the secondary battery of Comparative Example 3.
이러한 결과로부터, 본 발명의 실시예에 따른 올리고머를 포함하는 겔 전해질이 우수한 산화 안정성을 보여, 이차전지 내부에서 가스 발생량이 현저히 저감된 것을 알 수 있다.From these results, it can be seen that the gel electrolyte including the oligomer according to the embodiment of the present invention shows excellent oxidative stability, and the amount of gas generated in the secondary battery is significantly reduced.
실험예 4: 전기화학적 안정성 실험Experimental Example 4: Electrochemical Stability Experiment
<고전압 영역에서의 산화 안정성 실험>Oxidation Stability Test at High Voltage Range
선형 주사 볼타메트리(Linear sweep voltammetry)를 이용하여, 하기 표 3과 같은 실험 조건으로 2극 전지를 이용하여, 60℃에서 실시예 5의 겔 폴리머 전해질과 비교예 1의 액체 전해질에 대한 산화 안정성 실험을 실시하였다. 진행하였다. 그 결과를 도 3에 나타내었다.Oxidation stability of the gel polymer electrolyte of Example 5 and the liquid electrolyte of Comparative Example 1 at 60 ° C. using a bipolar cell under the experimental conditions shown in Table 3 using linear sweep voltammetry. The experiment was conducted. Proceeded. The results are shown in FIG.
작업전극Working electrode 덴카블랙 + 바인더 (KF7208, 주식회사 제온) = 95%:5%Denka Black + Binder (KF7208, Xeon Co., Ltd.) = 95%: 5%
상대 전극Counter electrode Li 금속Li metal
기준 전극Reference electrode Li 금속Li metal
전압 범위Voltage range OV~6VOV ~ 6V
스캔 레이트Scan rate 5mV/S, 605 mV / S, 60
비고Remarks 코인 반쪽 전지Coin halves
도 3에 나타낸 바와 같이, 비교예 1의 액체 전해질의 경우, 4.4V 영역에서부터 산화 변화가 크게 발생하는 것을 알 수 있다. 반면에, 실시예 5의 겔 폴리머 전해질은 5V 이상의 영역에서도 산화 변화가 나타나지 않는 것을 알 수 있다.As shown in FIG. 3, in the case of the liquid electrolyte of Comparative Example 1, it can be seen that a large change in oxidation occurs from the 4.4 V region. On the other hand, it can be seen that the gel polymer electrolyte of Example 5 does not show oxidative change even in a region of 5V or more.
즉, 이러한 결과로부터 화학식 1로 표시되는 올리고머로부터 유래된 폴리머를 포함하는 실시예 5의 겔 폴리머 전해질은 4.4V 이상의 고전압 영역에서도 산화에 대한 안정성이 굉장히 우수함을 알 수 있다. In other words, it can be seen that the gel polymer electrolyte of Example 5 including the polymer derived from the oligomer represented by Chemical Formula 1 has excellent stability against oxidation even in a high voltage region of 4.4 V or higher.
<저전압 영역에서의 환원 안정성 실험><Reduction Stability Test in Low Voltage Region>
순환전압전류법(Cyclic voltammetry)을 이용하여, 하기 표 4의 실험 조건으로 3극 전지를 이용하여, 저전압 영역에서 실시예 6의 겔 폴리머 전해질과 비교예 2의 액체 전해질에 대한 환원 안정성 실험을 실시하였다. 그 결과를 도 4에 나타내었다.By using cyclic voltammetry, using a three-pole battery under the experimental conditions of Table 4, the reduction stability experiments for the gel polymer electrolyte of Example 6 and the liquid electrolyte of Comparative Example 2 in the low voltage region It was. The results are shown in FIG.
작업전극Working electrode 흑연(상품명: AGM1 100)Graphite (brand name: AGM1 100)
상대 전극Counter electrode Li 금속Li metal
기준 전극Reference electrode Li 금속Li metal
전압 범위Voltage range OV~3VOV ~ 3V
스캔 레이트Scan rate 1mV/S1 mV / S
도 4에 나타낸 바와 같이, 화학식 1로 표시되는 올리고머로부터 유래된 폴리머를 포함하는 실시예 6의 겔 폴리머 전해질의 경우, 올리고머를 첨가하지 않은 비교예 2의 액체 전해질과 마찬가지로 그래프 상에서 올리고머가 환원되면서 발생되는 전류 증가 피크가 나타나지 않는 것을 알 수 있다.As shown in FIG. 4, in the case of the gel polymer electrolyte of Example 6 including the polymer derived from the oligomer represented by Formula 1, the oligomer was generated on the graph as in the liquid electrolyte of Comparative Example 2 without adding the oligomer. It can be seen that the current increase peak does not appear.
이러한 결과로부터 화학식 1로 표시되는 올리고머로부터 유래된 폴리머를 포함하는 경우에도, 실시예 6의 겔 폴리머 전해질은 환원 안정성이 저하되지 않은 것을 확인할 수 있다. From these results, even when it contains the polymer derived from the oligomer represented by General formula (1), it can be confirmed that the gel polymer electrolyte of Example 6 did not reduce reduction stability.
실험예 5: 상온 성능 평가Experimental Example 5: Evaluation of room temperature performance
실시예 5에서 제조된 겔 폴리머 전해질을 구비한 리튬 이차전지와 비교예 3에서 제조된 겔 폴리머 전해질을 구비한 리튬 이차전지를 각각 25℃에서 0.5C 정전류로 4.2V가 될 때까지 충전하고, 이후 4.2V의 정전압으로 충전하여 충전 전류가 0.275 mA가 되면 충전을 종료하였다. 이후, 10분간 방치환 다음 0.5C 정전류로 3.0V가 될 때까지 방전하였다. 상기 충방전을 700회 사이클 실시한 다음, 전지 용량을 측정하여 도 5에 나타내었다.The lithium secondary battery with the gel polymer electrolyte prepared in Example 5 and the lithium secondary battery with the gel polymer electrolyte prepared in Comparative Example 3 were charged to 25V at 0.5C constant current at 25 ° C., respectively. Charging was terminated when the battery was charged at a constant voltage of 4.2V and the charging current reached 0.275 mA. Thereafter, the battery was discharged for 10 minutes and then discharged until it became 3.0V at 0.5C constant current. After 700 cycles of charging and discharging, the battery capacity was measured and shown in FIG. 5.
도 5에 나타낸 바와 같이, 실시예 5의 리튬 이차전지는 700회 사이클을 진행한 후에도 용량 보유율의 변화가 거의 없었으며, 700회 사이클째에도 93% 이상의 용량 보유율을 보였다. As shown in FIG. 5, the lithium secondary battery of Example 5 had almost no change in capacity retention even after 700 cycles, and showed a capacity retention of 93% or more even at the 700th cycle.
이에 반해, 비교예 3의 리튬 이차전지는 초기 200회 사이클까지는 본 발명의 실시예 5의 이차전지와 유사한 용량 보유율을 보이다가 약 250회 사이클부터 현저히 감소하여, 700회 사이클에는 약 88% 미만으로 급격히 감소함을 보였다.In contrast, the lithium secondary battery of Comparative Example 3 exhibited a capacity retention rate similar to that of the secondary battery of Example 5 of the present invention until the initial 200 cycles, but decreased significantly from about 250 cycles, to about 88% in 700 cycles. It showed a sharp decrease.
따라서, 도 5에서 확인한 바와 같이, 본 발명의 실시예 5의 리튬 이차전지는 비교예 3의 리튬 이차전지에 비해 상온에서의 사이클 수명 특성이 향상된 것을 알 수 있다.Therefore, as confirmed in FIG. 5, it can be seen that the lithium secondary battery of Example 5 of the present invention has improved cycle life characteristics at room temperature compared to the lithium secondary battery of Comparative Example 3.
실험예 6: 저온 성능 평가Experimental Example 6: Evaluation of Low Temperature Performance
실시예 5에서 제조된 겔 폴리머 전해질을 구비한 리튬 이차전지와 비교예 3에서 제조된 겔 폴리머 전해질을 구비한 리튬 이차전지의 저온 성능을 평가하였고, 그 결과를 도 6에 나타내었다.The low temperature performance of the lithium secondary battery with the gel polymer electrolyte prepared in Example 5 and the lithium secondary battery with the gel polymer electrolyte prepared in Comparative Example 3 was evaluated, and the results are shown in FIG. 6.
구체적으로, 실시예 5 및 비교예 3의 리튬 이차전지의 저온 성능을 평가하기 위해, 실시예 5 및 비교예 3의 리튬 이차전지를 각각 0.5C rate로 SOC 50%을 맞춘 후, 약 3.65V, 400㎃h 전류밀도로 CC-CV(Constant current-Constant voltage)로 최초 충전 후, -10℃에서 4W 전력으로 30초간 방전을 하여 얻어지는 전압 강하를 통해 저온에서의 저항을 측정하였다.Specifically, in order to evaluate the low temperature performance of the lithium secondary batteries of Example 5 and Comparative Example 3, after adjusting the SOC 50% at 0.5C rate of the lithium secondary batteries of Example 5 and Comparative Example 3, respectively, about 3.65V, After the initial charging with CC-CV (Constant current-Constant voltage) at 400 mAh current density, the resistance at low temperature was measured through the voltage drop obtained by discharging for 30 seconds at 4W power at -10 ° C.
도 6에 나타낸 바와 같이, 본 발명의 올리고머를 포함하는 겔 폴리머 전해질을 구비한 실시예 5의 리튬 이차전지는 비교예 3의 리튬 이차전지에 비하여 전압 강하 정도가 상대적으로 적은 것을 알 수 있다.As shown in FIG. 6, it can be seen that the lithium secondary battery of Example 5 having the gel polymer electrolyte containing the oligomer of the present invention has a relatively low voltage drop compared to the lithium secondary battery of Comparative Example 3.
따라서, 본 발명의 올리고머를 포함하는 겔 폴리머 전해질을 구비한 실시예 5의 리튬 이차전지는 비교예 3의 이차전지 대비 저온 특성이 향상된 것을 알 수 있다.Therefore, it can be seen that the lithium secondary battery of Example 5 having the gel polymer electrolyte including the oligomer of the present invention has improved low temperature characteristics compared to the secondary battery of Comparative Example 3.
실험예 7: 열적 안정성 평가Experimental Example 7: Evaluation of Thermal Stability
실시예 5에서 제조된 겔 폴리머 전해질을 구비한 리튬 이차전지와 비교예 3에서 제조된 겔 폴리머 전해질을 구비한 리튬 이차전지를 각각 4.2V로 만충전한 상태에서 분해한 후 음극을 시차주사열량계(DSC: differential scanning calorimeter)로 측정하였다. 측정 조건은 25℃ 내지 400℃까지 10℃/min의 간격으로 측정하였다. 그 결과를 도 7에 나타내었다.After disassembling the lithium secondary battery having the gel polymer electrolyte prepared in Example 5 and the lithium secondary battery having the gel polymer electrolyte prepared in Comparative Example 3 at 4.2 V, the negative electrode was subjected to differential scanning calorimetry (DSC). : differential scanning calorimeter). Measurement conditions were measured at intervals of 10 ° C / min from 25 ° C to 400 ° C. The results are shown in FIG.
일반적으로, 초기 충전 시 음극 표면에 SEI (solid polymer electrolyte) 막이 형성되는데, 이 막이 고온에서 분해되지 않으면 음극과 전해질의 부반응이 방지되어 전지의 안정성이 향상된다. In general, a solid polymer electrolyte (SEI) film is formed on the surface of the negative electrode during initial charging. If the membrane is not decomposed at high temperature, side reaction between the negative electrode and the electrolyte is prevented, thereby improving battery stability.
도 7에 나타낸 바와 같이, 실시예 5의 이차전지의 경우, SEI 막의 분해온도가 255℃에서 90J/g인 반면, 비교예 3의 이차전지는 190℃에서 90J/g을 보였다.As shown in FIG. 7, in the secondary battery of Example 5, the decomposition temperature of the SEI film was 90 J / g at 255 ° C., whereas the secondary battery of Comparative Example 3 showed 90 J / g at 190 ° C. FIG.
즉, 본 발명의 실시예에 따라 올리고머를 포함한 겔 폴리머 전해질을 사용한 실시예 5의 이차전지는 음극 표면에서의 SEI 막 분해온도가 비교예 1에 비해 약 60℃ 이상 높게 나타나는 것을 알 수 있다. 따라서, 본 발명의 실시예 5의 리튬 이차전지는 비교예 3의 리튬 이차전지에 비하여 열정 안정성이 더욱 우수함을 확인할 수 있다.That is, the secondary battery of Example 5 using the gel polymer electrolyte containing the oligomer according to the embodiment of the present invention it can be seen that the decomposition temperature of the SEI film on the surface of the negative electrode is about 60 ℃ higher than in Comparative Example 1. Therefore, it can be seen that the lithium secondary battery of Example 5 of the present invention is more excellent in passion stability than the lithium secondary battery of Comparative Example 3.

Claims (15)

  1. 리튬염; Lithium salts;
    유기용매; 및Organic solvents; And
    하기 화학식 1로 표시되는 올리고머를 포함하는 것인 리튬 이차전지용 전해질:An electrolyte for a lithium secondary battery comprising an oligomer represented by Formula 1 below:
    [화학식 1][Formula 1]
    Figure PCTKR2017014432-appb-I000008
    Figure PCTKR2017014432-appb-I000008
    상기 화학식 1에서,In Chemical Formula 1,
    R은 지방족 탄화수소기 또는 방향족 탄화수소기이며,R is an aliphatic hydrocarbon group or an aromatic hydrocarbon group,
    R1 내지 R3는 각각 독립적으로 불소로 치환 또는 비치환된 탄소수 1 내지 5의 알킬렌기이고, R 1 to R 3 are each independently an alkylene group having 1 to 5 carbon atoms unsubstituted or substituted with fluorine,
    R4는 탄소수 1 내지 4의 알킬렌기이며,R 4 is an alkylene group having 1 to 4 carbon atoms,
    R'는 수소 또는 탄소수 1 내지 3의 알킬기이고,R 'is hydrogen or an alkyl group having 1 to 3 carbon atoms,
    a는 1 내지 3이며,a is 1 to 3,
    n은 반복단위 수이고,n is the number of repeat units,
    n은 1 내지 75 중 어느 하나의 정수이다.n is an integer of any one of 1 to 75.
  2. 청구항 1에 있어서,The method according to claim 1,
    상기 화학식 1로 표시되는 올리고머에서, In the oligomer represented by Formula 1,
    상기 지방족 탄화수소기는 치환 또는 비치환된 탄소수 4 내지 20의 사이클로알킬렌기; 이소시아네이트기(NCO)를 함유하는 치환 또는 비치환된 탄소수 4 내지 20의 사이클로알킬렌기; 치환 또는 비치환된 탄소수 4 내지 20의 사이클로알케닐렌기; 및 치환 또는 비치환된 탄소수 2 내지 20의 헤테로사이클로알킬렌기로 이루어진 군으로부터 선택된 적어도 하나 이상의 지환족 탄화수소기, 또는 치환 또는 비치환된 탄소수 1 내지 20의 알킬렌기; 이소시아네이트기(NCO)를 함유하는 치환 또는 비치환된 탄소수 1 내지 20의 알킬렌기; 치환 또는 비치환된 탄소수 1 내지 20의 알콕실렌기; 치환 또는 비치환된 탄소수 2 내지 20의 알케닐렌기; 및 치환 또는 비치환된 탄소수 2 내지 20의 알키닐렌기로 이루어진 군으로부터 선택된 선형 탄화수소기이고, The aliphatic hydrocarbon group may be substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms; A substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms containing an isocyanate group (NCO); A substituted or unsubstituted cycloalkenylene group having 4 to 20 carbon atoms; And at least one alicyclic hydrocarbon group selected from the group consisting of a substituted or unsubstituted heterocycloalkylene group having 2 to 20 carbon atoms, or a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms; Substituted or unsubstituted C1-C20 alkylene group containing an isocyanate group (NCO); A substituted or unsubstituted alkoxylene group having 1 to 20 carbon atoms; A substituted or unsubstituted alkenylene group having 2 to 20 carbon atoms; And a linear hydrocarbon group selected from the group consisting of substituted or unsubstituted alkynylene group having 2 to 20 carbon atoms,
    상기 방향족 탄화수소기는 치환 또는 비치환된 탄소수 6 내지 20의 아릴렌기; 또는 치환 또는 비치환된 탄소수 2 내지 20의 헤테로아릴렌기인 것인 리튬 이차전지용 전해질.The aromatic hydrocarbon group is substituted or unsubstituted arylene group having 6 to 20 carbon atoms; Or a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms.
  3. 청구항 1에 있어서, The method according to claim 1,
    상기 화학식 1로 표시되는 올리고머는 하기 화학식 1a로 표시되는 올리고머인 것인 리튬 이차전지용 전해질:The oligomer represented by Chemical Formula 1 is an oligomer represented by Chemical Formula 1a below: A lithium secondary battery electrolyte:
    [화학식 1a][Formula 1a]
    Figure PCTKR2017014432-appb-I000009
    Figure PCTKR2017014432-appb-I000009
    상기 화학식 1a에서,In Chemical Formula 1a,
    R은 지방족 탄화수소기 또는 방향족 탄화수소기이고,R is an aliphatic hydrocarbon group or an aromatic hydrocarbon group,
    R1은 불소로 치환 또는 비치환된 탄소수 1 내지 5의 알킬렌기이고, R 1 is an alkylene group having 1 to 5 carbon atoms substituted or unsubstituted with fluorine,
    n1은 반복단위 수이며,n1 is the number of repeat units,
    n1은 1 내지 75 중 어느 하나의 정수이다.n1 is an integer of any one of 1-75.
  4. 청구항 3에 있어서, The method according to claim 3,
    상기 화학식 1a로 표시되는 올리고머는 하기 화학식 1a-1로 표시되는 올리고머인 것인 리튬 이차전지용 전해질: The oligomer represented by Chemical Formula 1a is an oligomer represented by Chemical Formula 1a-1 below:
    [화학식 1a-1][Formula 1a-1]
    Figure PCTKR2017014432-appb-I000010
    Figure PCTKR2017014432-appb-I000010
    상기 화학식 1a-1에서, In Chemical Formula 1a-1,
    n2는 반복단위 수이며,n2 is the number of repeat units,
    n2는 20 내지 75 중 어느 하나의 정수다.n2 is an integer of any one of 20-75.
  5. 청구항 1에 있어서,The method according to claim 1,
    상기 화학식 1로 표시되는 올리고머는 리튬 이차전지용 전해질 전체 중량을 기준으로 0.5 중량% 내지 20 중량%로 포함되는 것인 리튬 이차전지용 전해질.The oligomer represented by the formula (1) is a lithium secondary battery electrolyte that is contained in 0.5 to 20% by weight based on the total weight of the lithium secondary battery electrolyte.
  6. 청구항 1에 있어서, The method according to claim 1,
    상기 화학식 1로 표시되는 올리고머는 리튬 이차전지용 전해질 전체 중량을 기준으로 0.5 중량% 내지 15 중량%로 포함되는 것인 리튬 이차전지용 전해질.The oligomer represented by the formula (1) is a lithium secondary battery electrolyte that is contained in 0.5 to 15% by weight based on the total weight of the lithium secondary battery electrolyte.
  7. 청구항 1에 있어서,The method according to claim 1,
    상기 화학식 1로 표시되는 올리고머를 포함하는 경우, 상기 리튬 이차전지용 전해질은 액체 전해질인 것인 리튬 이차전지용 전해질.When the oligomer represented by Formula 1 is included, the lithium secondary battery electrolyte is a liquid electrolyte for a lithium secondary battery.
  8. 청구항 1에 있어서,The method according to claim 1,
    상기 화학식 1로 표시되는 올리고머 유래의 폴리머를 포함하는 경우, 상기 리튬 이차전지용 전해질은 겔 폴리머 전해질인 것인 리튬 이차전지용 전해질.When the polymer derived from the oligomer represented by the formula (1), the lithium secondary battery electrolyte is a gel secondary battery electrolyte.
  9. 청구항 8에 있어서,The method according to claim 8,
    상기 화학식 1로 표시되는 올리고머 유래의 폴리머는 중합개시제 존재하에서 화학식 1로 표시되는 올리고머가 중합하여 3차원 구조로 형성된 매트릭스 폴리머인 것인 리튬 이차전지용 전해질.The polymer derived from the oligomer represented by Chemical Formula 1 is a matrix polymer formed in a three-dimensional structure by polymerization of the oligomer represented by Chemical Formula 1 in the presence of a polymerization initiator.
  10. 청구항 8에 있어서,The method according to claim 8,
    상기 겔 폴리머 전해질은 무기물 입자를 추가로 포함하는 것인 리튬 이차전지용 전해질. The gel polymer electrolyte further comprises an inorganic particle electrolyte for a lithium secondary battery.
  11. 청구항 10에 있어서,The method according to claim 10,
    상기 무기물 입자는 BaTiO3, BaTiO3, Pb(ZrxTi1-x)O3 (0≤x≤1) (PZT), Pb1 -bLabZr1-cTicO3 (PLZT, 여기서, 0<b<1, 0<c<1임), Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT), 하프니아(HfO2), SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiC 및 이들의 혼합체로부터 이루어진 군으로부터 선택된 단일물 또는 2종 이상의 혼합물을 포함하는 것인 리튬 이차전지용 전해질. The inorganic particles may include BaTiO 3 , BaTiO 3 , Pb (Zr x Ti 1-x ) O 3 (0 ≦ x ≦ 1) (PZT), Pb 1- b La b Zr 1-c Ti c O 3 (PLZT, where , 0 <b <1, 0 <c <1), Pb (Mg 1/3 Nb 2/3 ) O 3 -PbTiO 3 (PMN-PT), Hafnia (HfO 2 ), SrTiO 3 , SnO 2 , Lithium secondary comprising a single or a mixture of two or more selected from the group consisting of CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 , Al 2 O 3 , TiO 2 , SiC and mixtures thereof Battery electrolyte.
  12. 청구항 10에 있어서,The method according to claim 10,
    상기 무기물 입자는 겔 폴리머 전해질 전체 중량을 기준으로 10 중량% 내지 25 중량%가 포함되는 것인 리튬 이차전지용 전해질. The inorganic particles are 10 to 25% by weight based on the total weight of the gel polymer electrolyte electrolyte for a lithium secondary battery.
  13. 음극, 양극, 상기 음극 및 양극 사이에 개재된 분리막, 및A cathode interposed between the cathode, the anode, the cathode and the anode, and
    청구항 1의 리튬 이차전지용 전해질을 포함하는 것인 리튬 이차전지.Lithium secondary battery comprising a lithium secondary battery electrolyte of claim 1.
  14. 청구항 13에 있어서,The method according to claim 13,
    상기 리튬 이차전지용 전해질은 액체 전해질인 것인 리튬 이차전지.The lithium secondary battery electrolyte is a lithium secondary battery that is a liquid electrolyte.
  15. 청구항 13에 있어서,The method according to claim 13,
    상기 리튬 이차전지용 전해질은 겔 폴리머 전해질인 것인 리튬 이차전지.The lithium secondary battery electrolyte is a lithium secondary battery that is a gel polymer electrolyte.
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CN112074982B (en) * 2018-09-10 2023-10-13 株式会社Lg新能源 Thermosetting electrolyte composition, gel polymer electrolyte prepared from the same, and lithium secondary battery including the electrolyte
CN112074982A (en) * 2018-09-10 2020-12-11 株式会社Lg化学 Thermosetting electrolyte composition for lithium secondary battery, gel polymer electrolyte prepared from the thermosetting electrolyte composition, and lithium secondary battery comprising the electrolyte
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CN113711413A (en) * 2019-01-17 2021-11-26 株式会社Lg新能源 Electrolyte for lithium secondary battery and lithium secondary battery comprising same
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