WO2019088733A1 - Électrolyte pour batterie secondaire au lithium et batterie secondaire au lithium le comprenant - Google Patents

Électrolyte pour batterie secondaire au lithium et batterie secondaire au lithium le comprenant Download PDF

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Publication number
WO2019088733A1
WO2019088733A1 PCT/KR2018/013181 KR2018013181W WO2019088733A1 WO 2019088733 A1 WO2019088733 A1 WO 2019088733A1 KR 2018013181 W KR2018013181 W KR 2018013181W WO 2019088733 A1 WO2019088733 A1 WO 2019088733A1
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Prior art keywords
secondary battery
electrolyte
lithium secondary
formula
group
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PCT/KR2018/013181
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English (en)
Korean (ko)
Inventor
오정우
안경호
한준혁
이철행
Original Assignee
주식회사 엘지화학
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Priority claimed from KR1020180132195A external-priority patent/KR102227811B1/ko
Application filed by 주식회사 엘지화학 filed Critical 주식회사 엘지화학
Priority to PL18874455.1T priority Critical patent/PL3561936T3/pl
Priority to CN201880007159.2A priority patent/CN110178258B/zh
Priority to US16/477,348 priority patent/US10950895B2/en
Priority to JP2020502292A priority patent/JP7027628B2/ja
Priority to EP18874455.1A priority patent/EP3561936B1/fr
Publication of WO2019088733A1 publication Critical patent/WO2019088733A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H01M10/0567—Liquid materials characterised by the additives
    • 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
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • 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 and a lithium secondary battery comprising the same.
  • Electrochemical devices are one of the most sought-after fields of energy storage technology. Among them, attention is focused on rechargeable lithium secondary batteries.
  • the lithium secondary battery can be produced by applying the positive electrode active material and the negative electrode active material to the current collector in an appropriate thickness or by forming the active material itself into a film having an appropriate length and winding or laminating the separator together with the separator as an insulator, The electrode assembly is placed in a similar container, and then an electrolyte is injected.
  • the electrolyte may be a gel polymer electrolyte further comprising a liquid electrolyte or a matrix polymer including an electrolyte solvent in which a lithium salt is dissolved.
  • electrolyte solvent examples include ethylene carbonate, propylene carbonate, dimethoxyethane, gamma butyrolactone, N, N-dimethylformamide, tetrahydrofuran and acetonitrile.
  • the electrolyte solvent causes a side reaction at high voltage, and when stored at a high temperature for a long time, not only an oxidation reaction occurs but also a dendrite-type Li metal formed on the anode can easily react to generate an exothermic reaction.
  • the overcharge progresses above a certain SOC, the oxidation reaction of the electrolyte accelerates and the exothermic reaction between the Li metal on the surface of the negative electrode and the electrolyte formed due to excessive Li migration from the positive electrode to the negative electrode is intensified, have.
  • the present invention provides an electrolyte for a lithium secondary battery having improved wettability by lowering surface tension with respect to an electrode surface.
  • the present invention also provides a lithium secondary battery including the electrolyte for the lithium secondary battery.
  • an electrolyte for a lithium secondary battery comprising an oligomer represented by the following general formula (1) or a polymer derived from an oligomer represented by the general formula (1).
  • R 1 and R 2 are each independently a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms,
  • R 3 and R 4 are each independently hydrogen or a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms,
  • R 5 is hydrogen or a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms
  • R ' is an aliphatic hydrocarbon group or an aromatic hydrocarbon group
  • z is an integer of 1 to 10,
  • x is an integer of 1 to 15,
  • n is an integer of 1 to 3.
  • the aliphatic hydrocarbon group of R ' is selected from the group consisting of (a) a substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms, a substituted or unsubstituted cycloalkenylene group having 4 to 20 carbon atoms, (B) a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted alicyclic hydrocarbon group having 1 to 20 carbon atoms, a substituted or unsubstituted alicyclic hydrocarbon group having 1 to 20 carbon atoms, At least one aliphatic hydrocarbon group selected from the group consisting of a substituted or unsubstituted arylene group, an alkoxylene group, a substituted or unsubstituted alkenylene group having 2 to 20 carbon atoms, and a substituted or unsubstituted alkynylene group having 2 to 20 carbon
  • the aromatic hydrocarbon group of R ' may include at least one selected from the group consisting of a substituted or unsubstituted arylene group having 6 to 20 carbon atoms and a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms.
  • the aliphatic hydrocarbon group of R ' is a substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms, a substituted or unsubstituted cycloalkenylene group having 4 to 20 carbon atoms and a substituted or unsubstituted And at least one alicyclic hydrocarbon group selected from the group consisting of a heterocycloalkylene group having 2 to 20 carbon atoms.
  • the oligomer represented by the formula (1) may be at least one selected from oligomers represented by the following formulas (1a) and (1b).
  • R ' is an aliphatic hydrocarbon group or an aromatic hydrocarbon group
  • z1 and x1 are the number of repeating units
  • z1 is an integer of 1 to 10
  • x1 is an integer of any one of 1 to 15;
  • R ' is an aliphatic hydrocarbon group or an aromatic hydrocarbon group
  • z2 and x2 are the number of repeating units
  • z2 is an integer of 1 to 10
  • x2 is an integer of any one of 1 to 15.
  • the oligomer represented by Formula 1 may be at least one selected from the group consisting of oligomers represented by the following Formulas 1a-1 and 1b-1.
  • z1 and x1 are the number of repeating units
  • z1 is an integer of 1 to 10
  • x1 is an integer of any one of 1 to 15;
  • z2 and x2 are the number of repeating units
  • z2 is an integer of 1 to 10
  • x2 is an integer of any one of 1 to 15.
  • the electrolyte for a lithium secondary battery of the present invention may be a liquid electrolyte containing an oligomer represented by the general formula (1).
  • the oligomer represented by Formula 1 may be contained in an amount of 0.5 to 30% by weight, specifically 0.5 to 25% by weight based on the total weight of the electrolyte for a lithium secondary battery.
  • the electrolyte for a lithium secondary battery of the present invention may be a gel polymer electrolyte comprising an oligomer-derived polymer represented by the above formula (1).
  • the oligomer-derived polymer represented by Formula 1 may be a matrix polymer formed by polymerization of an oligomer represented by Formula 1 in the presence of a polymerization initiator to form a three-dimensional structure.
  • the oligomer-derived polymer represented by Formula 1 may be contained in an amount of 0.5 to 30% by weight, specifically 0.5 to 25% by weight based on the total weight of the electrolyte for a lithium secondary battery.
  • the lithium secondary battery including the electrolyte for a lithium secondary battery of the present invention can be provided.
  • the electrolyte for the lithium secondary battery may be a liquid electrolyte or a gel polymer electrolyte.
  • an oligomer having hydrophilic and hydrophobic functional groups or a polymer derived from such an oligomer can be used to manufacture an electrolyte for a lithium secondary battery that can improve wettability by lowering the surface tension with respect to the electrode surface and suppress side reactions of the electrolyte and the electrode. can do. Further, by including it, an increase in interfacial resistance of the electrode can be suppressed to prevent an average voltage drop, and as a result, a lithium secondary battery having improved charging / discharging efficiency can be manufactured.
  • the functional group may include “ a " to " b " carbon atoms.
  • the "alkyl group having 1 to 3 carbon atoms” means an alkyl group containing 1 to 3 carbon atoms, ie, -CH 3 , -CH 2 CH 3 , -CH 2 CH 2 CH 3 or -CH 2 (CH 2 ) CH 3 .
  • the "arylene group” means a functional group in which hydrogen atoms are separated from aromatic hydrocarbons.
  • the arylene group includes, but is not limited to, a phenylene group, a biphenylene group, a terphenylene group, a naphthylene group, or a phenanthrylene group, each of which is optionally substituted .
  • hetero means, unless otherwise defined, that at least one heteroatom selected from the group consisting of N, O, S, or P is contained in one functional group and the remainder is carbon do.
  • heterocycloalkylene group as used throughout this specification means that at least one hetero atom of N, O, S, or P exists in the ring compound having 2 to 20 carbon atoms instead of carbon.
  • substituted means that at least one hydrogen bonded to carbon is replaced with an element other than hydrogen, unless otherwise defined, and includes, for example, an alkyl group substituted with an alkyl group having 1 to 3 carbon atoms .
  • a lithium salt Organic solvent
  • an oligomer represented by the following formula (1) or an oligomer-derived polymer represented by the above formula (1) is included in one embodiment of the present invention.
  • R 1 and R 2 are each independently a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms,
  • R 3 and R 4 are each independently hydrogen or a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms,
  • R 5 is hydrogen or a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms
  • R ' is an aliphatic hydrocarbon group or an aromatic hydrocarbon group
  • z is an integer of 1 to 10,
  • x is an integer of 1 to 15,
  • n is an integer of 1 to 3.
  • the electrolyte for a lithium secondary battery of the present invention may be a lithium salt, an organic solvent, and a liquid electrolyte containing an oligomer represented by the formula (1).
  • the electrolyte for a lithium secondary battery of the present invention may be a gel polymer electrolyte for a lithium secondary battery comprising a lithium salt, an organic solvent, and an oligomer-derived polymer represented by the formula (1).
  • an electrolyte for a lithium secondary battery comprising a lithium salt, an organic solvent, and an oligomer represented by the formula (1).
  • the electrolyte for the lithium secondary battery may be a liquid electrolyte.
  • the lithium salt used in the lithium secondary battery electrolyte of the present invention can be used without limitation, those which are commonly used in a lithium secondary battery electrolyte, such as an anion, and containing the Li + in the lithium salt cation is 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 -, C 4 F
  • the lithium salt may be 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 , or a mixture of two or more thereof.
  • lithium bisperfluoroethanesulfonimide Li 2 N 2 (SO 2 C 2 F 5) 2)
  • LiFSI lithium fluorosulfonyl imide, LiN (SO 2 F) 2)
  • LiTFSI lithium (bis) trifluoromethanesulfonimide, LiN (SO 2 CF 3) 2
  • a lithium salt such as lithium already deuyeom represented by the limited without Can be used.
  • the lithium salt is 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 ) or more danilmul selected from the group consisting of 2 or two And mixtures thereof.
  • the lithium salt can be appropriately changed within a range that is generally usable, but it can be specifically contained in the electrolyte in the range of 0.1 M to 3 M, specifically 0.8 M to 2.5 M. If the concentration of the lithium salt exceeds 3M, the viscosity of the electrolyte may increase and the lithium ion transfer effect may be lowered.
  • the organic solvent may include at least one organic solvent selected from the group consisting of a cyclic carbonate organic solvent, a linear carbonate organic solvent, a linear ester organic solvent and a cyclic ester organic solvent.
  • the organic solvent may include a cyclic carbonate-based organic solvent and a linear carbonate-based organic solvent.
  • cyclic carbonate-based organic solvent examples include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3- Pentylene carbonate, and vinylene carbonate, or a mixture of two or more thereof.
  • organic solvents having a high viscosity such as ethylene carbonate, which has a high dielectric constant and dissociates the lithium salt in the electrolyte well .
  • the linear carbonate-based organic solvent is an organic solvent having a low viscosity and a low dielectric constant. Typical examples thereof include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethyl methyl carbonate EMC), methyl propyl carbonate, and ethyl propyl carbonate.
  • DMC dimethyl carbonate
  • DEC diethyl carbonate
  • EMC ethyl methyl carbonate
  • propyl carbonate methyl propyl carbonate
  • ethyl propyl carbonate ethyl propyl carbonate
  • the organic solvent may further include a linear ester organic solvent and / or a cyclic ester organic solvent to produce an electrolytic solution having a high electrical conductivity.
  • linear ester organic solvents may include at least one selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate and butyl propionate have.
  • the cyclic ester organic solvent may include at least one selected from the group consisting of? -Butyrolactone,? -Valerolactone,? -Caprolactone,? -Valerolactone and? -Caprolactone .
  • organic solvent may be added with an organic solvent commonly used in an electrolyte for a lithium secondary battery, if necessary, without limitation.
  • an ether organic solvent and a nitrile organic solvent may further include at least one organic solvent.
  • the ether-based organic solvent may include any one selected from the group consisting of dimethyl ether, diethyl ether, dipropyl ether, methyl ethyl ether, methyl propyl ether and ethyl propyl ether.
  • the nitrile organic solvent may be, for example, acetonitrile, propionitrile, butyronitrile, valeronitrile, caprilonitrile, heptanenitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile, 2-fluorobenzonitrile, 4 May include any one selected from the group consisting of fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, 4-fluorophenylacetonitrile .
  • the electrolyte for a lithium secondary battery of the present invention may include an oligomer represented by the following formula (1).
  • R 1 and R 2 are each independently a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms,
  • R 3 and R 4 are each independently hydrogen or a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms,
  • R 5 is hydrogen or a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms
  • R ' is an aliphatic hydrocarbon group or an aromatic hydrocarbon group
  • z is an integer of 1 to 10,
  • x is an integer of 1 to 15,
  • n is an integer of 1 to 3.
  • the aliphatic hydrocarbon group of R ' is selected from the group consisting of (a) a substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms, a substituted or unsubstituted cycloalkenylene group having 4 to 20 carbon atoms, (B) at least one substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted C1 to C20 alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted C1 to C20 alkoxy group, a substituted or unsubstituted C2 to C20 alicyclic hydrocarbon group, And at least one linear hydrocarbon group selected from the group consisting of a substituted or unsubstituted alkenylene group having 2 to 20 carbon atoms and a substituted or unsubstituted alkynylene group having 2 to 20 carbon atoms, have.
  • the aromatic hydrocarbon group for R ' may include at least one selected from substituted or unsubstituted arylene groups having 6 to 20 carbon atoms and substituted or unsubstituted heteroarylene groups having 2 to 20 carbon atoms.
  • the aliphatic hydrocarbon group of R ' is a substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms, a substituted or unsubstituted cycloalkenylene group having 4 to 20 carbon atoms, and a substituted or unsubstituted carbon number And at least one alicyclic hydrocarbon group selected from the group consisting of 2 to 20 heterocycloalkylene groups.
  • the oligomer represented by the formula (1) contains an acrylate-based functional group which is a hydrophilic moiety capable of forming a cross-linking bond at both ends, and also contains a siloxane group (-Si-O-) and a urethane O) - group, it is possible to lower the interfacial resistance by imparting a surfactant role in the cell and by balancing affinity with the anode or separator (SRS layer) which is a hydrophilic part and the cathode or separator fabric which is a hydrophobic part . Therefore, the electrolyte for the lithium secondary battery including the oligomer represented by the above formula (1) can further improve the wettability effect.
  • the oligomer represented by the above formula (1) forms a stable ion conductive membrane on the surface of the cathode at the time of initial charging, and at the same time suppresses the side reaction between the Li metal deposited on the surface of the anode and the electrolyte, It is possible to suppress an increase in resistance and an average voltage change during charging and discharging therefrom. Therefore, a lithium secondary battery improved in charge / discharge efficiency and high rate characteristics can be provided.
  • the oligomer represented by the general formula (1) of the present invention contains a siloxane group (- [Si-O] -) and a urethane group as repeating units of the main chain, and the oligomer additionally contains a- . That is, since the oligomer structure does not contain additional -Si- group as a repeating unit, the ratio of the functional groups at both terminals can be increased and the molecular weight of the entire polymer can be lowered. Therefore, Can further increase the content of the entire oligomer relative to an oligomer further including a -Si- group (e.g., [Si-O] -Si- structure in the main chain repeat unit). Therefore, the reaction rate of the gel polymer can be advantageously taken, and the hardness of the gel polymer can be increased to enhance the hardness of the whole cell, so that it can be more advantageously used for safety evaluation such as impact evaluation which gives physical impact.
  • a siloxane group - [Si-O] -
  • the oligomer represented by the formula (1) may be at least one selected from the group consisting of oligomers represented by the following formulas (1a) and (1b).
  • R ' is an aliphatic hydrocarbon group or an aromatic hydrocarbon group
  • z1 and x1 are the number of repeating units
  • z1 is an integer of 1 to 10
  • x1 is an integer of any one of 1 to 15;
  • R ' is an aliphatic hydrocarbon group or an aromatic hydrocarbon group
  • z2 and x2 are the number of repeating units
  • z2 is an integer of 1 to 10
  • x2 is an integer of any one of 1 to 15.
  • the oligomer represented by Formula 1 may be selected from the group consisting of oligomers represented by the following Formulas 1a-1 and 1b-1.
  • z1 and x1 are the number of repeating units
  • z1 is an integer of 1 to 10
  • x1 is an integer of any one of 1 to 15;
  • z2 and x2 are the number of repeating units
  • z2 is an integer of 1 to 10
  • x2 is an integer of any one of 1 to 15.
  • the weight average molecular weight (Mw) of the oligomer represented by the formula (1) can be controlled by the number of repeating units, and is about 1,000 g / mol to 100,000 g / mol, specifically 1,000 g / mol to 50,000 g / Specifically from 1,000 g / mol to 10,000 g / mol.
  • Mw weight average molecular weight
  • the weight average molecular weight of the oligomer is less than 1,000 g / mol, the electrochemical stability and the role of the surfactant can not be expected, and since the functional group content is low, the effect of suppressing the side reaction of the electrode surface may be insignificant. / mol, the solubility in an organic solvent may be lowered.
  • the weight average molecular weight may mean a value converted to standard polystyrene measured by Gel Permeation Chromatography (GPC), and unless otherwise specified, the molecular weight may mean a weight average molecular weight.
  • GPC Gel Permeation Chromatography
  • the GPC conditions are measured using an Agilent 1200 series.
  • the column used herein may be a PL mixed B column of Agilent, and THF may be used as a solvent.
  • the oligomer represented by Formula 1 is used in an amount of 0.5 to 30% by weight, specifically 0.5 to 25% by weight, more specifically 0.5 to 10% by weight, based on the total weight of the electrolyte for a lithium secondary battery, By weight to 0.5% by weight to 5% by weight.
  • the content of the oligomer represented by the general formula (1) is 0.5% by weight or more, the control of reactivity with lithium metal and the electrochemical stability effect can be expected. When the content is less than 30% by weight, And at the same time, it is possible to prevent the disadvantages such as deterioration of the ion conductivity by improving the movement restriction of the lithium ion. If the content of the oligomer represented by the above formula (1) is more than 30% by weight, the solubility of the oligomer in the electrolyte decreases and the viscosity of the electrolyte increases, thereby decreasing the ionic conductivity of the electrolyte. As a result, the voltage drop of the battery may be caused due to an increase in the interface resistance of the electrode.
  • the electrolyte for a lithium secondary battery of the present invention can prevent degradation of the non-aqueous electrolyte due to decomposition of the non-aqueous electrolyte in an environment of high output, further improve low temperature high rate discharge characteristics, high temperature stability, overcharge prevention,
  • the composition may further include additional additives capable of forming a more stable ion conductive film on the surface of the electrode.
  • Such additional additives may include at least one selected from the group consisting of a sulfonate compound, a halogen-substituted carbonate compound, a nitrile compound, a cyclic sulfite compound, and a cyclic carbonate compound.
  • the sul- tonic compound may be selected from the group consisting of 1,3-propane sultone (PS), 1,4-butane sul- thone, ethene sul- thone, 1,3-propene sul- thone (PRS), 1,4- 3-propenesultone, and the like.
  • the sulfone compound may be contained in an amount of 5% by weight or less based on the total weight of the nonaqueous electrolyte solution. If the content of the sulfonate compound in the nonaqueous electrolyte exceeds 5 wt%, a thick film of excess additive may be formed, resulting in increased resistance and deterioration of output.
  • the halogen-substituted carbonate compound is fluoroethylene carbonate (FEC), and may be contained in an amount of 5 wt% or less based on the total weight of the non-aqueous electrolyte. If the content of the halogen-substituted carbonate compound exceeds 5% by weight, the cell swelling performance may deteriorate.
  • FEC fluoroethylene carbonate
  • the nitrile compound may be at least one selected from the group consisting of succinonitrile, adiponitrile (Adn), acetonitrile, propionitrile, butyronitrile, valeronitrile, caprylonitrile, heptanenitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile, In the group consisting of 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, and 4-fluorophenylacetonitrile At least one compound selected.
  • the nitrile compound may be contained in an amount of 8% by weight or less based on the total weight of the nonaqueous electrolyte solution. If the total content of the nitrile compound in the nonaqueous electrolyte exceeds 8 wt%, resistance increases due to an increase in the film formed on the surface of the electrode, and battery performance may be deteriorated.
  • cyclic sulfite-based compound examples include ethylene sulfite, methyl ethylene sulfite, ethyl ethylene sulfite, 4,5-dimethylethylene sulfite, 4,5-diethyl ethylene sulfite, - dimethylpropylene sulfite, 4,5-diethylpropylene sulfite, 4,6-dimethylpropylene sulfite, 4,6-diethylpropylene sulfite and 1,3-butylene glycol sulfite. Based on the total weight of the nonaqueous electrolyte solution. If the content of the cyclic sulfite-based compound exceeds 5% by weight, a thick film of excess additive may be formed, resulting in increased resistance and deterioration of output.
  • the cyclic carbonate compound may be vinylene carbonate (VC) or vinylethylene carbonate.
  • the cyclic carbonate compound may include up to 3% by weight based on the total weight of the non-aqueous electrolyte. If the content of the cyclic carbonate compound in the non-aqueous electrolyte exceeds 3% by weight, the cell swelling inhibition performance may deteriorate.
  • the additional additive may be a cyclic carbonate-based compound.
  • additional additives may be used in admixture of two or more, and may be contained in an amount of 20 wt% or less, specifically 0.01 wt% to 20 wt%, preferably 0.1 wt% to 10 wt%, based on the total amount of the electrolytic solution. If the content of the additive additive is less than 0.01% by weight, the effect of improving the low temperature power of the battery and improving the high-temperature storage characteristics and high-temperature lifetime characteristics are insignificant. If the content of the additive additive exceeds 20% by weight, There is a possibility that a side reaction in the electrolytic solution is excessive.
  • the additive for forming the SEI film when excessively added, it can not be sufficiently decomposed at a high temperature, and may be present in the electrolyte solution at room temperature without being reacted or precipitated. As a result, a side reaction in which the lifetime or the resistance characteristic of the secondary battery is lowered may occur.
  • a lithium salt, an organic solvent, and an oligomer-derived polymer represented by the above formula (1) A lithium salt, an organic solvent, and an oligomer-derived polymer represented by the above formula (1).
  • the electrolyte for a lithium secondary battery can be formed by thermally polymerizing a composition for a gel polymer electrolyte comprising the lithium salt, the organic solvent, the oligomer represented by the Formula 1, and a polymerization initiator.
  • the oligomer-derived polymer represented by Formula 1 may include a matrix polymer formed by crosslinking the oligomer represented by Formula 1 in a three-dimensional structure in the presence of a polymerization initiator.
  • the electrolyte for a lithium secondary battery of the present invention may be a gel electrolyte in which a non-aqueous electrolyte in which the lithium salt is dissolved is contained in a matrix polymer formed by crosslinking the oligomer represented by Formula 1 in a three-dimensional structure.
  • the description of the lithium salt and the organic solvent, and the type and concentration of the oligomer contained in the gel polymer electrolyte composition for preparing the electrolyte for a lithium secondary battery according to the present invention is the same as that described above, It is omitted.
  • the oligomer represented by Formula 1 may be used in an amount of 0.5 to 30% by weight, specifically 0.5 to 25% by weight, more preferably 0.5 to 10% by weight, based on the total weight of the gel polymer electrolyte composition, Specifically 0.5% to 5% by weight.
  • the content of the oligomer represented by Formula 1 is within the above range, that is, in the range of 0.5 wt% to 30 wt%, a polymer network having excellent mechanical strength can be formed, and thus a secondary battery having improved performance can be manufactured.
  • the content of the oligomer represented by the general formula (1) is 0.5% by weight or more based on the total weight of the composition for a gel polymer electrolyte, the polymer matrix by oligomer can be easily formed and the mechanical strength of the gel polymer electrolyte can be secured have.
  • the content of the oligomer represented by the general formula (1) is 30% by weight or less based on the total weight of the composition for a gel polymer electrolyte, an increase in resistance due to the addition of an excessive amount of oligomer is prevented, The wettability can be improved and the pre-gel reaction can be prevented. Furthermore, the ion conductivity can be secured by improving the movement limitation of lithium ions, and the cycle life characteristics can be improved.
  • the amount of the oligomer represented by Formula 1 is more than 30% by weight, the solubility of the oligomer in the composition for a gel polymer electrolyte is lowered, and the viscosity of the composition is increased to deteriorate the wettability, A voltage drop of < / RTI >
  • the oligomer-derived polymer represented by Formula 1 is used in an amount of 0.5 to 30 wt%, specifically 0.5 to 25 wt%, more specifically 0.5 to 10 wt%, based on the total weight of the electrolyte for a lithium secondary battery, More specifically from 0.5% to 5% by weight.
  • the oligomer-derived polymer represented by Formula 1 is a matrix polymer in which the oligomer represented by Formula 1 is formed into a three-dimensional structure by thermal polymerization reaction, and its content is the oligomer represented by Formula 1 contained in the composition for a gel polymer electrolyte Is preferably the same as the content of .
  • the content of the oligomer-derived polymer represented by the above-mentioned formula (1) is 0.5 weight% or more, the same physical properties as the mechanical strength of the gel polymer electrolyte can be secured. If it is 30% by weight or less, the increase in resistance due to the addition of an excessive amount of oligomer can be prevented, and the ionic conductivity can be ensured by restricting the movement restriction of lithium ions. If the content of the oligomer-derived polymer represented by the above formula (1) is more than 30% by weight, the ion conductivity of the electrolyte is lowered, and the voltage drop of the battery may be caused due to an increase in the interface resistance with the electrode.
  • the oligomer-based polymer represented by the above formula (1) forms a stable ion conductive film on the electrode surface at the time of initial charging, suppresses side reactions between Li metal deposited on the surface of the cathode upon overcharging and the electrolyte, It is possible to suppress an increase in the interfacial resistance of the electrode and an average voltage change during charging and discharging resulting from the increase in the resistance of the electrode relative to the electrolyte for the conventional lithium secondary battery.
  • the oligomer-derived polymer represented by the above formula (1) has the ability to dissociate the lithium salt to improve the lithium ion mobility.
  • it is a stable repeating unit of the main chain and is extremely stable electrochemically. (-Si-O-) and the like, it is possible to control the side reaction of the lithium ion (Li + ) and the decomposition reaction of the lithium salt, 2 can be reduced. Therefore, ignition or the like can be suppressed at the time of overcharging, and the stability of the secondary battery can be further improved.
  • the oligomer-derived polymer represented by Formula 1 of the present invention contains a siloxane group (- [Si-O] -) and a urethane group as repeating units of the main chain, It is preferable not to include it. That is, since the oligomer structure does not contain additional -Si- group as a repeating unit, the ratio of the functional groups at both terminals can be increased and the molecular weight of the entire polymer can be lowered. Therefore, Can further increase the content of the entire oligomer relative to an oligomer further including a -Si- group (e.g., [Si-O] -Si- structure in the main chain repeat unit). Therefore, the reaction rate of the gel polymer can be advantageously taken, and the hardness of the gel polymer can be increased to enhance the hardness of the whole cell, so that it can be more advantageously used for safety evaluation such as impact evaluation which gives physical impact.
  • a siloxane group - [Si-O] -
  • the polymerization initiator used for preparing the gel polymer electrolyte may be a conventional polymerization initiator known in the art.
  • the polymerization initiator may be decomposed by heat to form a radical, and react with an oligomer represented by the general formula (1) by free radical polymerization to form a gel polymer electrolyte.
  • the polymerization initiator may be an azo-based polymerization initiator or a peroxide-based polymerization initiator.
  • Typical 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 and at least one peroxide compound selected from the group consisting of 2,2'-azobis (2-cyanobutane), dimethyl 2,2'-azobis Azobis (iso-butyronitrile)) and 2,2'-azobis (isobutyronitrile) (2,2'-azobis (isobutyronitrile)
  • a group consisting of 2'-azobisdimethyl-valeronitrile (AMVN) Emitter may include at least one azo compound selected.
  • the polymerization initiator may be decomposed by heat in a secondary battery at 30 ° C to 100 ° C, specifically 60 ° C to 80 ° C, or decomposed at room temperature (5 ° C to 30 ° C) to form radicals, and free radicals
  • the polymerizable oligomer reacts with the acrylate-based compound by polymerization to form a gel polymer electrolyte.
  • the polymerization initiator may be included in an amount of about 0.01 part by weight to about 20 parts by weight, specifically about 5 parts by weight, based on 100 parts by weight of the entire oligomer.
  • the gelation reaction is easily performed to increase the gel polymer conversion
  • Gel polymer electrolyte properties can be ensured, the unreacted polymerization initiator after the polymerization reaction can be prevented from causing side reactions, and the wettability of the electrolyte solution to the electrode can be improved.
  • nitrogen or oxygen gas is generated in the process of generating radicals by heat or the like.
  • This gas generation is most likely to lead to a gas trap or a gas bubbling phenomenon in the process of forming a gel polymer electrolyte.
  • Such gas generation causes defects in the gel polyelectrolyte, resulting in deterioration of electrolyte quality. Therefore, when the polymerization initiator is included in the above range, it is possible to more effectively prevent the disadvantage that a large amount of gas is generated.
  • the electrolyte for the lithium secondary battery may be a liquid electrolyte or a gel polymer electrolyte.
  • the lithium secondary battery of the present invention When the electrolyte for a lithium secondary battery is a liquid electrolyte, the lithium secondary battery of the present invention includes an anode assembly, a cathode assembly, and a separator layer selectively interposed between the anode assembly and the cathode assembly, , And injecting an electrolyte for a lithium secondary battery of the present invention.
  • the electrolyte for a lithium secondary battery is a gel polymer electrolyte comprising a polymer matrix formed by polymerization between oligomers represented by Formula 1
  • the lithium secondary battery of the present invention may include a positive electrode, a negative electrode, And then the electrolyte assembly for a lithium secondary battery is injected and cured to form an electrode assembly.
  • the in-situ polymerization may be performed by E-BEAM, gamma ray, room temperature or high temperature aging process, and thermal polymerization may be performed according to one embodiment of the present invention.
  • the polymerization time is about 2 minutes to 48 hours
  • the thermal polymerization temperature may be 60 to 100 ⁇ ⁇ , specifically 60 to 80 ⁇ ⁇ .
  • the positive electrode, the negative electrode, and the separator may be any of those conventionally manufactured and used in the production of a lithium secondary battery.
  • the positive electrode may be manufactured by forming a positive electrode mixture layer on the positive electrode current collector.
  • the positive electrode mixture layer may be formed by coating a positive electrode slurry containing a positive electrode active material, a binder, a conductive material and a solvent on a positive electrode collector, followed by drying and rolling.
  • the positive electrode collector is not particularly limited as long as it has electrical conductivity without causing chemical change in the battery.
  • the positive electrode collector may be formed of a metal such as carbon, stainless steel, aluminum, nickel, titanium, sintered carbon, , Nickel, titanium, silver, or the like may be used.
  • the cathode active material is a compound capable of reversibly intercalating and deintercalating lithium, and may specifically include a lithium composite metal oxide including lithium and at least one metal such as cobalt, manganese, nickel, or aluminum have. More specifically, the lithium composite metal oxide may be at least one selected from the group consisting of lithium-manganese-based oxides (for example, LiMnO 2 and LiMn 2 O 4 ), lithium-cobalt oxides (for example, LiCoO 2 ), lithium- (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.
  • LiMnO 2 and LiMn 2 O 4 lithium-cobalt oxides
  • LiCoO 2 lithium-
  • lithium-manganese-cobalt oxide e. g., (in which LiCo 1-Y2 Mn Y2 O 2 , 0 ⁇ Y2 ⁇ 1), LiMn 2-z1 Co z1 O 4 ( here, 0 ⁇ z1 ⁇ 2) and the like
  • the lithium composite metal oxide may be LiCoO 2 , LiMnO 2 , LiNiO 2 , 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 lithium nickel cobalt aluminum oxide (e.g., Li (Ni 0.8 Co 0.15 Al 0.05 ) O 2, etc.) and the like.
  • lithium nickel cobalt aluminum oxide e.g., Li (Ni 0.8 Co 0.15 Al 0.05 ) O 2, etc.
  • the cathode active material may be contained in an amount of 40% by weight to 90% by weight, specifically 40% by weight to 75% by weight, based on the total weight of the solid content in the cathode slurry.
  • the binder is a component that assists in bonding of the active material to the conductive material and bonding to the current collector, and is usually added in an amount of 1 to 30 wt% based on the total weight of the solid content in the positive electrode slurry.
  • binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene (Ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluorine rubber, various copolymers and the like.
  • PVDF polyvinylidene fluoride
  • CMC carboxymethylcellulose
  • EPDM tetrafluoroethylene
  • EPDM tetrafluoroethylene
  • EPDM sulfonated EPDM
  • Such a conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery.
  • Conductive fibers such as carbon fiber and metal fiber;
  • Metal powders such as carbon fluoride, aluminum, and nickel powder;
  • Conductive whiskey 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 usually added in an amount of 1 to 30% by weight based on the total weight of the solid content in the positive electrode slurry.
  • the conductive material may be selected from the group consisting of acetylene black series such as Chevron Chemical Company, Denka Singapore Private Limited, Gulf Oil Company products, Ketjenblack, EC series Armak Company), Vulcan XC-72 (Cabot Company) and Super P (Timcal Co.), and the like.
  • acetylene black series such as Chevron Chemical Company, Denka Singapore Private Limited, Gulf Oil Company products, Ketjenblack, EC series Armak Company), Vulcan XC-72 (Cabot Company) and Super P (Timcal Co.), and the like.
  • the solvent may include an organic solvent such as N-methyl-2-pyrrolidone (NMP), and may be used in an amount that provides a preferable viscosity when the positive electrode active material and optionally a binder and a conductive material are included.
  • NMP N-methyl-2-pyrrolidone
  • the solid content in the slurry containing the cathode active material, and optionally the binder and the conductive material may be 10 wt% to 70 wt%, preferably 20 wt% to 60 wt%.
  • the cathode may be a metal electrode using a metal or a quasi-metal thin film alone, or a structure in which the metal or a quasi metal thin film is stacked on an anode current collector.
  • the metal or metalloid may be selected from the group consisting of Li, Cu, Ni, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Sn, Ag, Pt, and Au.
  • the cathode may be a Li metal electrode.
  • the negative electrode may be formed by using a metal electrode alone or by stacking a metal or metalloid thin film on the negative electrode current collector, or 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 current collector with a slurry containing a negative electrode active material, a binder, a conductive material, a solvent, and the like, followed by drying and rolling.
  • the anode current collector generally has a thickness of 3 to 500 mu m.
  • the negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery.
  • Examples of the negative electrode current collector include copper, stainless steel, aluminum, nickel, titanium, sintered carbon, copper or stainless steel Surface-treated with carbon, nickel, titanium, silver or the like, aluminum-cadmium alloy, or the like can be used.
  • fine unevenness can be formed on the surface to enhance the bonding force of the negative electrode active material, and it can be used in various forms such as films, sheets, foils, nets, porous bodies, foams and nonwoven fabrics.
  • the negative electrode active material may be at least one selected from the group consisting of a carbon material capable of reversibly intercalating / deintercalating lithium ions, a metal composite oxide, a material capable of doping and dedoping lithium, and a transition metal oxide And may further include one or more.
  • the carbonaceous material capable of reversibly intercalating / deintercalating lithium ions is not particularly limited as long as it is a carbonaceous anode active material generally used in a lithium ion secondary battery.
  • the carbonaceous material include crystalline carbon, Amorphous carbon or any combination thereof.
  • the crystalline carbon include graphite such as natural graphite or artificial graphite in the form of amorphous, plate-like, flake, spherical or fiber, and examples of the amorphous carbon include soft carbon (soft carbon) Or hard carbon, mesophase pitch carbide, fired coke, and the like.
  • Si As the material capable of doping and dedoping lithium, Si, SiO x (0 ⁇ x? 2), Si-Y alloy (Y is an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, Rare earth elements and combinations thereof, but not Si), Sn, SnO 2 , Sn-Y (wherein Y is at least one element selected from the group consisting of alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements, Element and an element selected from the group consisting of combinations thereof, and not Sn), and at least one of them may be mixed with SiO 2 .
  • Si-Y alloy Y is an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, Rare earth elements and combinations thereof, but not Si
  • Sn, SnO 2 Sn-Y (wherein Y is at least one element selected from the group consisting of alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements, Element
  • the element Y may be at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ge, P, As, Sb, Bi, Te, Po, and combinations thereof.
  • 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 contained in an amount of 80% by weight to 99% by weight based on the total weight of the solid content in the negative electrode slurry.
  • the binder is a component that assists in bonding between the conductive material, the active material and the current collector, and is usually added in an amount of 1 to 30% by weight based on the total weight of the solid content in the negative electrode slurry.
  • binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene
  • PVDF polyvinylidene fluoride
  • CMC carboxymethylcellulose
  • EPDM ethylene-propylene-diene polymer
  • sulfonated-EPDM styrene-butadiene rubber
  • fluorine rubber various copolymers thereof.
  • 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 to 20 wt% based on the total weight of the solid content in the negative electrode slurry.
  • Such a conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery.
  • the solvent may include water or an organic solvent such as NMP, alcohol, etc., and may be used in an amount in which the negative electrode active material and, optionally, a binder, a conductive material, and the like are contained in a desired viscosity.
  • the slurry containing the negative electrode active material and, optionally, the binder and the conductive material may be contained in such a manner that the solid concentration of the slurry is 50% by weight to 75% by weight, preferably 50% by weight to 65% by weight.
  • the separation membrane blocks the internal short circuit of both electrodes and impregnates the electrolyte.
  • the separation membrane composition is prepared by mixing a polymer resin, a filler and a solvent, and then the separation membrane composition is directly coated on the electrode and dried Or may be formed by casting and drying the separation membrane composition on a support, and then laminating the separation membrane film peeled off from the support on the electrode.
  • the separator may be a porous polymer film commonly used, such as a porous polymer film made of a polyolefin-based polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, and an ethylene / methacrylate copolymer
  • the polymer film may be used alone or as a laminate thereof, or may be a nonwoven fabric made of a conventional porous nonwoven fabric, for example, glass fiber of high melting point, polyethylene terephthalate fiber or the like, but is not limited thereto.
  • the pore diameter of the porous separation membrane is generally 0.01 to 50 ⁇ m, and the porosity may be 5 to 95%.
  • the thickness of the porous separator may be generally in the range of 5 to 300 mu m.
  • the external shape of the lithium secondary battery of the present invention is not particularly limited, but may be a cylindrical shape, a square shape, a pouch shape, a coin shape, or the like using a can.
  • NCM LiNi 3/5 Co 1/5 Mn 1/5 O 2 ; NCM
  • carbon black as a conductive material
  • PVDF polyvinylidene fluoride
  • NMP N-methyl-2-pyrrolidone
  • the positive electrode mixture slurry was applied to an aluminum (Al) thin film having a thickness of about 20 ⁇ and dried to produce a positive electrode, followed by a roll press to prepare a positive electrode.
  • a lithium metal electrode was used as a cathode.
  • the positive electrode, the negative electrode and a separator composed of three layers of polypropylene / polyethylene / polypropylene (PP / PE / PP) were sequentially laminated to produce an electrode assembly.
  • the assembled electrode assembly was housed in the battery case, and the electrolyte for the lithium secondary battery was injected and stored at room temperature for 2 days to prepare a coin cell type lithium secondary battery including a liquid electrolyte for a lithium secondary battery.
  • a liquid electrolyte for a lithium secondary battery and a coin cell type lithium secondary battery comprising the same were prepared in the same manner as in Example 1, except that 20 g of the oligomer represented by the formula (1a-1) was contained in 80 g of the organic solvent at the time of preparing the liquid electrolyte. (See Table 1 below).
  • a liquid electrolyte for a lithium secondary battery and a coin cell type lithium secondary battery comprising the same were prepared in the same manner as in Example 1 except that 10 g of the oligomer represented by the general formula (1a-1) was contained in 90 g of the organic solvent in the production of the liquid electrolyte. (See Table 1 below).
  • a liquid electrolyte for a lithium secondary battery and a coin cell type lithium secondary battery comprising the same were prepared in the same manner as in Example 1 except that 25 g of the oligomer represented by the formula (1a-1) was added to 75 g of the organic solvent at the time of preparing the liquid electrolyte. (See Table 1 below).
  • a liquid electrolyte for a lithium secondary battery and a coin cell type lithium secondary battery comprising the same were prepared in the same manner as in Example 1 except that 30 g of the oligomer represented by the formula (1a-1) was contained in 70 g of the organic solvent in the production of the liquid electrolyte. (See Table 1 below).
  • a liquid electrolyte for a lithium secondary battery and a coin cell type lithium secondary battery comprising the same were prepared in the same manner as in Example 1, except that 33 g of the oligomer represented by the formula (1a-1) was contained in 67 g of the organic solvent in the production of the liquid electrolyte. (See Table 1 below).
  • a liquid electrolyte for a lithium secondary battery and a coin cell type lithium secondary battery comprising the same were prepared in the same manner as in Example 1 except that the oligomer represented by the general formula (1a-1) was not included in the preparation of the liquid electrolyte See Table 1).
  • Example 1 Liquid electrolyte for lithium secondary battery Lithium salt Amount of organic solvent added (g) Oligomer The Addition amount (g) Example 1 1M LiPF 6 99.5 1a-1 0.5 Example 2 1M LiPF 6 80 1a-1 20 Example 3 1M LiPF 6 90 1a-1 10 Example 4 1M LiPF 6 90 1b-1 10 Example 5 1M LiPF 6 75 1a-1 25 Example 6 1M LiPF 6 70 1a-1 30 Example 7 1M LiPF 6 67 1a-1 33 Comparative Example 1 1M LiPF 6 100 - - Comparative Example 2 1M LiPF 6 99.5 2 0.5
  • a lithium secondary battery comprising a gel polymer electrolyte
  • LiNi 3/5 Co 1/5 Mn 1/5 O 2 as a positive electrode active material
  • carbon black as a conductive material
  • PVDF polyvinylidene fluoride
  • NMP solvent N-methyl-2-pyrrolidone
  • the positive electrode mixture slurry was applied to an aluminum (Al) thin film having a thickness of about 20 ⁇ and dried to produce a positive electrode, followed by a roll press to prepare a positive electrode.
  • a lithium metal electrode was used as a cathode.
  • the positive electrode, the negative electrode and a separator composed of three layers of polypropylene / polyethylene / polypropylene (PP / PE / PP) were sequentially laminated to produce an electrode assembly.
  • the assembled electrode assembly was housed in the battery case, and the composition for a gel polymer electrolyte for a lithium secondary battery was injected thereinto, heated at 60 ° C. for 24 hours and stored at room temperature for 2 days to contain a gel polymer electrolyte for a lithium secondary battery Coin cell type lithium secondary battery.
  • a coin cell type lithium secondary battery comprising a composition for a gel polymer electrolyte for a lithium secondary battery and a gel polymer electrolyte for a lithium secondary battery produced from the composition was prepared (see Table 2 below).
  • Example 8 A coin cell type lithium secondary battery comprising a composition for a gel polymer electrolyte for a lithium secondary battery and a gel polymer electrolyte for a lithium secondary battery produced from the composition was prepared (see Table 2 below).
  • a coin cell type lithium secondary battery comprising a composition for a gel polymer electrolyte for a lithium secondary battery and a gel polymer electrolyte for a lithium secondary battery produced therefrom was prepared in the same manner as in Example 10 (see Table 2 below).
  • composition for a gel polymer electrolyte 25 g of the oligomer represented by the formula 1a-1, 74 g of the organic solvent, 25 g of dimethyl 2,2'-azobis (2-methylpropionate) (CAS No. 2589-57 -3) was added to prepare a gel polymer electrolyte composition for a lithium secondary battery, a composition for a gel polymer electrolyte for a lithium secondary battery and a gel polymer for a lithium secondary battery produced therefrom were prepared in the same manner as in Example 8 A coin cell type lithium secondary battery containing an electrolyte was prepared (see Table 2 below).
  • the gel polymer electrolyte composition In the preparation of the gel polymer electrolyte composition, 30 g of the oligomer represented by the general formula (1a-1), dimethyl 2,2'-azobis (2-methylpropionate) (CAS No. 2589-57 -3) was added to prepare a gel polymer electrolyte composition for a lithium secondary battery, a composition for a gel polymer electrolyte for a lithium secondary battery and a gel polymer for a lithium secondary battery produced therefrom were prepared in the same manner as in Example 8 A coin cell type lithium secondary battery containing an electrolyte was prepared (see Table 2 below).
  • a composition for a gel polymer electrolyte and a composition for a gel polymer electrolyte were prepared in the same manner as in Example 9, except that the oligomer represented by Formula 2 was used instead of the oligomer represented by Formula 1a-1 in the preparation of the gel polymer electrolyte composition (See Table 2 below). ≪ tb > < TABLE >
  • Example 8 1M LiPF 6 99.49 1a-1 0.5 0.01
  • Example 9 1M LiPF 6 79.9 1a-1 20 0.1
  • Example 10 1M LiPF 6 89.9 1a-1 10 0.1
  • Example 11 1M LiPF 6 89.9 1b-1 10 0.1
  • Example 12 1M LiPF 6 74.9 1a-1 25 0.1
  • Example 13 1M LiPF 6 69.85 1a-1 30 0.15
  • Li / Li (150 ⁇ ) symmetry beaker cell) system manufactured by using Li foil was prepared, and then the liquid electrolyte for secondary battery prepared in Examples 1 to 7 and the secondary battery prepared in Comparative Examples 1 and 2 And a liquid electrolyte for a battery were respectively injected.
  • the charge transfer resistance (Rct) measured after 2 hours while flowing 10 mV alternating current using Electrochemical Impedance Spectroscopy (EIS) is shown in Table 3 below.
  • the initial charge transfer resistance value in Table 3 indicates the charge transfer resistance value after injecting the Li / Li electrode into the electrolyte.
  • Example 2 82 Example 3 97
  • Example 4 105 Example 5 75
  • Example 6 52 Example 7 50 Comparative Example 1 7,510 Comparative Example 2 330
  • the secondary of Example 3 which contains an oligomer represented by the general formula (1a-1) in which the content ratio of the siloxane group (-Si-O-) having a low number of acrylate groups at the end and a low reactivity with Li ions is relatively high,
  • the effect of suppressing the chemical reaction between the Li metal and the electrolyte is superior to that of the liquid electrolyte for a lithium secondary battery of Example 4 including the oligomer represented by the formula 1b-1 in the same amount, Low.
  • the wettability of the electrolyte becomes lower and the relative Li metal /
  • the chemical reaction between the Li metal and the electrolyte occurs under an environmental condition in which Li precipitation is induced such as overcharging and the like and the by-products produced by the decomposition of the electrolyte solution are laminated on the Li metal surface. Therefore, the charge transfer resistance value is about 330 ohms As compared with the electrolyte for lithium secondary batteries of Examples 1 to 7.
  • the gel of Example 10 which contains an oligomer represented by the general formula (1a-1) in which the content ratio of the siloxane group (-Si-O-) having a low number of acrylate groups at the end and a low reactivity with Li ion is relatively high
  • the polymer electrolyte composition since the chemical reactivity between the Li metal and the electrolyte is reduced and the surface diffusion reaction is suppressed as compared with the gel polymer electrolyte composition of Example 11 containing the same amount of the oligomer represented by the general formula (1b-1) The resistance increase rate is relatively low.
  • the lithium secondary batteries having the liquid electrolyte for lithium secondary batteries prepared in Examples 1 to 7 and the lithium secondary batteries having the liquid electrolyte for lithium secondary batteries prepared in Comparative Examples 1 and 2 were respectively charged at room temperature (25 ° C) / 4.2 V Constant current - The battery was fully charged at a constant voltage, and discharged at SOC 50% to 2.5 C for 10 seconds to perform initial charging and discharging.
  • Comparative Example 2 in which the lithium secondary battery of Comparative Example 1 having a liquid electrolyte having a liquid electrolyte for a lithium secondary battery not containing an oligomer and the liquid electrolyte for a lithium secondary battery comprising an oligomer represented by Formula 2
  • the initial resistance values are respectively 135 mohm and 93 mohm, which is higher than those of the lithium secondary batteries of Examples 1 to 6.
  • the voltage drop of the lithium secondary battery having the gel polymer electrolyte prepared in Examples 8 to 13 and the lithium polymer secondary cell having the gel polymer electrolyte prepared in Comparative Example 3 was measured in the same manner as in Experimental Example 3, The initial resistance of each cell was measured through the obtained voltage drop, and it is shown in Table 6 below.
  • Example 9 59
  • Example 10 69
  • Example 11 62
  • Example 12 55
  • Example 13 75 Comparative Example 3 100
  • the generation of by-products can be suppressed due to the decrease in reactivity between the Li metal and the electrolyte, 76 mohm or less.
  • the initial resistance value is 100 mohm, which is higher than that of the lithium secondary batteries of Examples 8 to 13.
  • the lithium secondary batteries having the liquid electrolyte for lithium secondary batteries manufactured in Examples 1 to 6 and the lithium secondary batteries having the liquid electrolyte for lithium secondary batteries prepared in Comparative Examples 1 and 2 were subjected to voltage driving ranges of 3.0 V to 4.2 V Under a constant current of 0.33 C / 4.2 V at a constant current of -25 V and a discharge of SOC 50% to 2.5 C for 10 seconds. Subsequently, the charge and discharge process was repeated three times at 25 ° C and 0.33C / 0.33C under a voltage driving range of 3.0 V to 4.2 V, and the discharge capacity after the last 3 cycles was measured with a PNE-0506 charge / discharge device (manufacturer: PNE solution, 5V, 6A). The results are shown in Table 7 below.
  • Example 1 63.2
  • Example 2 71.2
  • Example 3 69.2
  • Example 4 67.4
  • Example 5 73.5
  • Example 6 64.1 Comparative Example 1 59.7 Comparative Example 2 60.5
  • the discharge capacity of the lithium secondary battery having the liquid electrolyte for lithium secondary batteries manufactured in Examples 1 to 6 after 3 cycles is mostly 63.2 mAh or more.
  • a liquid electrolyte comprising an oligomer represented by the general formula (1a-1) in which the content ratio of a siloxane group (-Si-O-) having a low number of acrylate groups at a terminal and a low reactivity with Li ions is relatively high
  • the discharge capacity of the lithium secondary battery of Example 3 is further improved as compared with the lithium secondary battery of Example 4 having the liquid electrolyte containing the oligomer represented by Formula 1b-1.
  • the lithium secondary batteries having the gel polymer electrolyte prepared in Examples 8 to 13 and the gel polymer electrolyte prepared in Comparative Example 3 were prepared in the same manner as in Experimental Example 5, (capacity) were measured, and the results are shown in Table 8 below.
  • the discharge capacity was 52.4 mAh, which was higher than that of the lithium secondary batteries of Examples 8 to 13 .
  • the lithium secondary battery manufactured in Examples 1 to 14 and the lithium secondary batteries prepared in Comparative Examples 1 to 3 were subjected to SOC 100% using a PNE-0506 charge / discharge device (PNE solution, 5V, 6A, , And the temperature was measured at SOC 140% after overcharging under 1C, bakelite plate (insulation condition) and 8.3V (cutoff) condition.
  • Table 9 The results are shown in Table 9 below.
  • Example 1 Temperature at 140% SOC (° C) Liquid electrolyte Example 1 67
  • Example 2 56
  • Example 3 61
  • Example 4 62
  • Example 5 53
  • Example 6 58
  • Example 7 Comparative Example 1
  • Comparative Example 2 75
  • Example 8 62
  • Example 9 48
  • Example 10 52
  • Example 11 53
  • Example 12 42
  • Example 13 48
  • Example 14 59 Comparative Example 3 69
  • the lithium secondary battery having a liquid electrolyte for a lithium secondary battery manufactured in Examples 1 to 6 exhibits a temperature of less than 67 ° C at an SOC of 140%.
  • the lithium secondary battery having the gel polymer electrolyte prepared in Examples 8 to 14 exhibits a SOC of 140% to 62 ° C or less.
  • the lithium secondary batteries prepared in Examples 1 to 14 and the lithium secondary batteries prepared in Comparative Examples 1 to 3 were charged to 4.25 V at 1 C / 1 C at 45 ⁇ , left to stand for 10 minutes, And discharged until 3.0 V was reached. The charge and discharge were performed as one cycle, and 500 cycles of charge and discharge were performed.
  • Capacity retention ratio (%) (capacity after 500 cycles / capacity after one cycle) x 100
  • Example 1 Liquid electrolyte
  • Example 2 94.2
  • Example 3 93.5
  • Example 4 93.1
  • Example 5 95.5
  • Example 6 91.1
  • Example 7 87.2 Comparative
  • Example 2 72
  • Example 8 89.2
  • Example 9 92.0
  • Example 10 91.5
  • Example 11 90.5
  • Example 12 92.9
  • Example 13 87.4
  • Example 14 82.5 Comparative Example 3 78.5
  • the lithium secondary battery having the liquid electrolyte for a lithium secondary battery manufactured in Examples 1 to 7 has a capacity retention rate of 87.2% or more even after 500 cycles.

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  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
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Abstract

La présente invention concerne un électrolyte pour batterie secondaire au lithium et une batterie secondaire au lithium le comprenant. La présente invention concerne plus précisément : un électrolyte pour batterie secondaire au lithium contenant un sel de lithium, un solvant organique et un oligomère représenté par la formule 1 ou un polymère dérivé d'un oligomère représenté par la formule 1 décrite dans la présente invention ; et une batterie secondaire au lithium le comprenant, ce qui inhibe la réactivité à un métal lithium de façon à améliorer les performances générales de ladite batterie.
PCT/KR2018/013181 2017-11-03 2018-11-01 Électrolyte pour batterie secondaire au lithium et batterie secondaire au lithium le comprenant WO2019088733A1 (fr)

Priority Applications (5)

Application Number Priority Date Filing Date Title
PL18874455.1T PL3561936T3 (pl) 2017-11-03 2018-11-01 Elektrolit dla akumulatora litowego i zawierający go akumulator litowy
CN201880007159.2A CN110178258B (zh) 2017-11-03 2018-11-01 用于锂二次电池的电解质和包括该电解质的锂二次电池
US16/477,348 US10950895B2 (en) 2017-11-03 2018-11-01 Electrolyte for lithium secondary battery and lithium secondary battery including the same
JP2020502292A JP7027628B2 (ja) 2017-11-03 2018-11-01 リチウム二次電池用電解質及びこれを含むリチウム二次電池
EP18874455.1A EP3561936B1 (fr) 2017-11-03 2018-11-01 Électrolyte pour batterie secondaire au lithium et batterie secondaire au lithium le comprenant

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KR20170146223 2017-11-03
KR10-2017-0146223 2017-11-03
KR10-2018-0132195 2018-10-31
KR1020180132195A KR102227811B1 (ko) 2017-11-03 2018-10-31 리튬 이차전지용 전해질 및 이를 포함하는 리튬 이차전지

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JP2022530431A (ja) * 2019-08-30 2022-06-29 エルジー エナジー ソリューション リミテッド リチウム二次電池用電解質及びこれを含むリチウム二次電池

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Publication number Priority date Publication date Assignee Title
JP2022530431A (ja) * 2019-08-30 2022-06-29 エルジー エナジー ソリューション リミテッド リチウム二次電池用電解質及びこれを含むリチウム二次電池
JP7278658B2 (ja) 2019-08-30 2023-05-22 エルジー エナジー ソリューション リミテッド リチウム二次電池用電解質及びこれを含むリチウム二次電池
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CN113966557A (zh) * 2019-09-03 2022-01-21 株式会社Lg新能源 非水性电解液和包含该电解液的锂二次电池
JP2022530430A (ja) * 2019-09-03 2022-06-29 エルジー エナジー ソリューション リミテッド 非水電解液及びこれを含むリチウム二次電池
JP7278657B2 (ja) 2019-09-03 2023-05-22 エルジー エナジー ソリューション リミテッド 非水電解液及びこれを含むリチウム二次電池
CN113966557B (zh) * 2019-09-03 2024-02-20 株式会社Lg新能源 非水性电解液和包含该电解液的锂二次电池

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