WO2019093853A1 - Électrolyte non aqueux pour batterie secondaire au lithium et batterie secondaire au lithium le comprenant - Google Patents

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

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WO2019093853A1
WO2019093853A1 PCT/KR2018/013783 KR2018013783W WO2019093853A1 WO 2019093853 A1 WO2019093853 A1 WO 2019093853A1 KR 2018013783 W KR2018013783 W KR 2018013783W WO 2019093853 A1 WO2019093853 A1 WO 2019093853A1
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secondary battery
lithium secondary
lithium
additive
group
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PCT/KR2018/013783
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English (en)
Korean (ko)
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김하은
임영민
김광연
이철행
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주식회사 엘지화학
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Priority claimed from KR1020180138408A external-priority patent/KR102242252B1/ko
Application filed by 주식회사 엘지화학 filed Critical 주식회사 엘지화학
Priority to JP2020502297A priority Critical patent/JP7045589B2/ja
Priority to EP18875224.0A priority patent/EP3648231B1/fr
Priority to CN201880050190.4A priority patent/CN111052485B/zh
Priority to PL18875224T priority patent/PL3648231T3/pl
Priority to US16/634,959 priority patent/US11309583B2/en
Publication of WO2019093853A1 publication Critical patent/WO2019093853A1/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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a nonaqueous electrolyte for a lithium secondary battery and a lithium secondary battery comprising the same.
  • the lithium secondary battery developed in the early 1990s is attracting attention because of its high operating voltage and energy density.
  • the currently used lithium secondary battery is composed of a carbonaceous anode capable of intercalating and deintercalating lithium ions, a cathode made of a lithium-containing transition metal oxide or the like, and a non-aqueous electrolyte solution in which an appropriate amount of a lithium salt is dissolved in a carbonate-based organic solvent.
  • the lithium secondary battery is charged and discharged by transferring energy while repeating the phenomenon that lithium ions discharged from the positive electrode are inserted into the negative electrode, for example, carbon particles and discharged again when discharged by charging.
  • a part of the electrolyte additive components and organic solvents are decomposed in the range of 0.5 V to 3.5 V during the initial charging to form a film on the surface of the negative electrode, and lithium ions generated from the positive electrode move to the negative electrode, And reacts with the electrolytic solution to produce compounds such as Li 2 CO 3 , Li 2 O, and LiOH. These compounds form a passivation layer on the surface of the negative electrode, which is referred to as a solid electrolyte interface (SEI) film.
  • SEI solid electrolyte interface
  • the SEI film formed during the initial charge prevents the reaction between the lithium ion and the carbonaceous anode or other materials during charging and discharging. It also acts as an ion tunnel, allowing only lithium ions to pass through. This ion tunnel serves to prevent the organic solvent of the electrolyte having a large molecular weight, which is solvated by lithium ion, to co-intercalate with the carbon-based anode to collapse the structure of the carbon-based cathode. Therefore, in order to improve the high-temperature cycle characteristics and the low-temperature output of the lithium secondary battery, a solid SEI film must always be formed on the cathode of the lithium secondary battery.
  • the organic solvent used for the non-aqueous electrolyte of the lithium secondary battery is stored for a long time at a high temperature, it is generally oxidized by a side reaction with the transition metal oxide released from the anode to generate gas, Deformation of the electrode assembly occurs.
  • the SEI film is gradually collapsed to expose the negative electrode and the exposed negative electrode reacts with the electrolyte to continuously generate a side reaction Therefore, gases such as CO, CO 2 , CH 4 and C 2 H 6 are generated.
  • gases such as CO, CO 2 , CH 4 and C 2 H 6 are generated.
  • the internal pressure of the battery is increased to cause deformation such as cell swelling.
  • the battery deteriorates and the battery may be ignited or exploded.
  • a non-aqueous electrolyte solution for a lithium secondary battery which comprises an additive capable of forming a stable film on an electrode surface.
  • the present invention also provides a lithium secondary battery including the nonaqueous electrolyte solution for the lithium secondary battery, which has improved high temperature and overcharge stability and low temperature output characteristics.
  • Lithium salts Organic solvent; And an additive,
  • the additive is selected from the group consisting of lithium difluorophosphate (LiPO 2 F 2 ): LiDFP, fluorobenzene (FB), tetravinyl silane (TVS) and one sulfonate group or sulfate group which is a mixed additive containing a compound in a weight ratio of 1: 2 to 8: 0.05 to 0.3: 0.5 to 2.
  • LiPO 2 F 2 lithium difluorophosphate
  • FB fluorobenzene
  • TVS tetravinyl silane
  • sulfonate group or sulfate group which is a mixed additive containing a compound in a weight ratio of 1: 2 to 8: 0.05 to 0.3: 0.5 to 2.
  • the weight ratio of the lithium difluorophosphate, the fluorobenzene, the tetravinylsilane, and the compound containing one sulfonate group or the sulfate group may be 1: 2 to 6: 0.05 to 0.3: 0.5 to 1.5.
  • the one sulfonate group or the compound containing a sulfate group may be selected from the group consisting of ethylene sulfate, trimethylene sulfate, methyl trimethylene sulfate, 1,3-propane sultone, 1 At least one selected from the group consisting of 4-butane sultone, ethene sultone, 1,4-butene sultone, 1-methyl-1,3-propane sultone and 1,3- And may specifically be at least one selected from the group consisting of ethylene sulfate, trimethylene sulfate, 1,3-propane sultone and 1,3-propenesultone.
  • the additive may be included in an amount of 1 to 18% by weight based on the total weight of the nonaqueous electrolyte solution for a lithium secondary battery.
  • the nonaqueous electrolyte solution for a lithium secondary battery of the present invention can be used for forming at least one SEI film selected from the group consisting of a halogen-substituted carbonate compound, a nitrile compound, a cyclic carbonate compound, a phosphate compound, a borate compound and a lithium salt compound
  • the first additive may further comprise a first additive.
  • the nonaqueous electrolyte solution for a lithium secondary battery of the present invention may further comprise at least one second additive for forming an SEI film selected from the group consisting of diphenyl disulfide, di-p-tolyl disulfide and bis (4-methoxyphenyl) disulfide (BMPDS) May be further included.
  • BMPDS bis (4-methoxyphenyl) disulfide
  • a lithium secondary battery comprising a negative electrode, a positive electrode, a separator interposed between the negative electrode and the positive electrode, and a nonaqueous electrolyte
  • the nonaqueous electrolyte solution provides a lithium secondary battery comprising the nonaqueous electrolyte solution for a lithium secondary battery of the present invention.
  • the lithium-nickel-manganese-cobalt-based oxide may be Li (Ni 1/3 Mn 1/3 Co 1/3 ) O 2 , Li (Ni 0.35 Mn 0.28 Co 0.37 ) O 2 , Li (Ni 0.6 Mn 0.2 Co 0.2 ) O 2 , And at least one selected from the group consisting of 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 .
  • a nonaqueous electrolyte solution for a lithium secondary battery capable of forming a stable SEI film on the surface of a negative electrode by including an additive in which four kinds of compounds are mixed in a specific ratio. Also, by including it, it is possible to manufacture a lithium secondary battery having improved performance such as high temperature, overcharge stability, and low temperature output characteristics.
  • Example 1 is a graph showing a result of evaluation of low-temperature output characteristics of a lithium secondary battery according to Experimental Example 1 of the present invention.
  • Example 2 is a graph showing the overcharge stability evaluation result of the lithium secondary battery of Example 1 according to Experimental Example 6 of the present invention.
  • Lithium salts Organic solvent; And an additive,
  • the additive may be selected from the group consisting of lithium difluorophosphate (LiDFP), fluorobenzene (FB), tert-vinylsilane (TVS) and a compound containing one sulfonate group or sulfate group in a ratio of 1: To 8: 0.05 to 0.3: 0.5 to 2 by weight, based on the total weight of the non-aqueous electrolyte.
  • LiDFP lithium difluorophosphate
  • FB fluorobenzene
  • TVS tert-vinylsilane
  • the lithium salt may be any of those conventionally used in an electrolyte for a lithium secondary battery, and may include, for example, Li + as a cation of the lithium salt
  • the anions include F - , Cl - , Br - , I - , NO 3 - , N (CN) 2 - , ClO 4 - , BF 4 - , B 10 Cl 10 - , PF 6 - , CF 3 SO 3 - CH 3 CO 2 -, CF 3 CO 2 -, AsF 6 -, SbF 6 -, AlCl 4 -, AlO 4 -, CH 3 SO 3 -, 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 CF 3) 2 PF 4 -, (CF 3) 3 PF 3 -, (CF
  • 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 , LiCH 3 SO 3 , LiFSI (lithium fluorosulfonyl imide, LiN (SO 2 F) 2 ), LiTFSI (lithium bis) trifluoromethanesulfonimide, LiN (SO 2 CF 3 ) 2 and LiBETI (lithium bisperfluoroethanesulfonimide, 2 C 2 F 5 ) 2 ), or a mixture of two or more thereof.
  • LiFSI lithium fluorosulfonyl imide, LiN (SO 2 F) 2
  • LiTFSI lithium bis
  • LiN (SO 2 CF 3 ) 2 and LiBETI lithium bisperfluor
  • 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 does not include LiDFP, which is a lithium salt contained in the mixed additive.
  • the lithium salt may be appropriately changed within a range that is generally usable, but specifically, it may be contained in the electrolyte in an amount of 0.1M to 3M, specifically 0.8M to 2.5M. If the concentration of the lithium salt exceeds 3M, the viscosity of the non-aqueous electrolyte increases to lower the lithium ion transporting effect, and the wettability of the non-aqueous electrolyte deteriorates, making it difficult to form a uniform SEI film.
  • the organic solvent may minimize decomposition due to an oxidation reaction or the like during charging and discharging of the secondary battery,
  • a carbonate-based organic solvent, an ether-based organic solvent or an ester-based organic solvent may be used alone or in combination of two or more.
  • the carbonate-based organic solvent in the organic solvent may include at least one of a cyclic carbonate-based organic solvent and a linear carbonate-based organic solvent.
  • the cyclic carbonate-based organic solvent is selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, (Ethylene carbonate), ethylene carbonate (ethylene carbonate) having a high dielectric constant and ethylene carbonate (ethylene carbonate) having a dielectric constant higher than that of ethylene carbonate, And a mixed solvent of propylene carbonate having a low melting point.
  • the linear carbonate-based organic solvent may be a solvent having a low viscosity and a low dielectric constant, such as dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethylmethyl carbonate (EMC) And at least one selected from the group consisting of propyl carbonate, ethyl carbonate, propyl carbonate, and ethyl propyl carbonate, and more specifically, dimethyl carbonate.
  • DMC dimethyl carbonate
  • DEC diethyl carbonate
  • EMC ethylmethyl carbonate
  • the ether organic solvent may be selected from the group consisting of dimethyl ether, diethyl ether, dipropyl ether, methyl ethyl ether, methyl propyl ether and ethyl propyl ether, or a mixture of two or more thereof. It is not.
  • the ester-based organic solvent may include at least one selected from the group consisting of a linear ester organic solvent and a cyclic ester organic solvent.
  • the linear ester organic solvent may be any one selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, and butyl propionate. A mixture of two or more thereof, and the like may be used, but the present invention is not limited thereto.
  • cyclic ester organic solvent examples include any one selected from the group consisting of? -Butyrolactone,? -Valerolactone,? -Caprolactone,? -Valerolactone and? -Caprolactone, or 2 Mixtures of two or more species may be used, but are not limited thereto.
  • the organic solvent may be a high-viscosity cyclic carbonate-based organic solvent having high permittivity and dissociating the lithium salt in the electrolyte. Further, in order to produce an electrolyte having a higher electrical conductivity, the organic solvent may be used together with the above-mentioned environmental carbonate-based organic solvent to prepare a low viscosity, low dielectric constant linear carbonate compound and linear ester compound such as dimethyl carbonate and diethyl carbonate They can be mixed and used in an appropriate ratio.
  • the organic solvent may be a mixture of a cyclic carbonate compound and a linear carbonate compound.
  • the weight ratio of the cyclic carbonate compound to the linear carbonate compound in the organic solvent may be 10:90 to 70:30.
  • the nonaqueous electrolyte solution for a lithium secondary battery of the present invention may include an additive which is a mixture of lithium difluorophosphate, fluorobenzene, tetravinylsilane, and one sulfonate group or a compound containing a sulfate group.
  • lithium difluorophosphate represented by the following formula (1), which is one of the components of the mixed additive, is a component for realizing long-term lifetime improvement effect of a secondary battery, and is electrochemically decomposed
  • the SEI film can be formed to prevent exposure to the non-aqueous electrolyte. As a result, it is possible to suppress the generation of O 2 from the anode and the side reaction between the anode and the electrolyte, thereby improving the durability of the battery. Further, since the di-fluorophosphate structure is reduced when the battery is driven, a stable and stable SEI film can be formed on the surface of the negative electrode, thereby improving durability and high-temperature storage characteristics of the battery.
  • the fluorobenzene represented by the following formula (2) which is one of the components of the mixed additive, is a component for improving the stability during overcharging.
  • the product decomposed at a specific potential forms a polymer layer on the surface of the positive electrode and the negative electrode, By preventing the side reaction of the electrode, the high temperature storage stability of the lithium secondary battery can be improved.
  • Tetravinyl silane (TVS) represented by the following chemical formula (3), which is one of the mixed additive components, forms a solid SEI film through physical adsorption and electrochemical reaction on the surfaces of the positive and negative electrodes, It is possible to prevent exposure of the cathode. As a result, it is possible to suppress the side reaction of the non-aqueous electrolyte at high temperature and the electrode, and to prevent the increase in resistance, so that the high temperature storage stability of the lithium secondary battery can be improved.
  • one sulfonate group or a compound containing a sulfate group, which is one of the above-mentioned mixed additive components can form a stable coating film that is not cracked even when stored at high temperature on the surface of the negative electrode.
  • the negative electrode coated with such a coating suppresses the decomposition of the non-aqueous solvent by the negative active material during storage at a high temperature even when a carbon material highly crystallized by the activity of natural graphite or artificial graphite is used for the negative electrode, have. Therefore, high temperature stability of the lithium secondary battery and cycle life and capacity characteristics at high temperature storage can be improved, and resistance reduction can be suppressed.
  • the one sulfonate group or the compound containing a sulfate group may be selected from the group consisting of ethylene sulfate (Esa) represented by the following formula (4a), trimethylene sulfate (TMS) represented by the following formula (4b) Methyl trimethylene sulfate (MTMS), 1,3-propane sultone (PS), 1,4-butane sultone, ethene sultone, 1,4-butene sultone And 1-methyl-1,3-propenesultone and 1,3-propenesultone (PRS) represented by the following formula (4e).
  • Esa ethylene sulfate
  • TMS trimethylene sulfate
  • MTMS Methyl trimethylene sulfate
  • PS 1,3-propane sultone
  • PRS 1-methyl-1,3-propenesultone and 1,3-propenesultone
  • the one sulfonate group or the compound containing a sulfate group may be at least one or more of ethylene sulfate, trimethylene sulfate, 1,3-propane sultone and 1,3-propene sultone.
  • Such a sulfonate group or a compound containing a sulfate group may be used in an amount of up to 6.5% by weight, specifically 0.1% by weight to 6.5% by weight, more specifically 0.5% by weight to 4.0% by weight, based on the total weight of the nonaqueous electrolyte solution for a lithium secondary battery .
  • the compound containing lithium difluorophosphate, fluorobenzene, tetravinylsilane and one sulfonate group or sulfate group may be used in a ratio of 1: 2 to 8: 0.05 to 0.3: 0.5 to 2, particularly 1: 2 to 6 : 0.05 to 0.3: 0.5 to 1.5 by weight.
  • weight ratio of fluorobenzene to lithium difluorophosphate is 8 or less, an increase in internal resistance of the battery due to excessive use of the additive can be prevented. Further, when the weight ratio of the fluorobenzene is 2 or more, stability at the time of overcharging can be improved.
  • the weight ratio of the tetravinylsilane to the lithium difluorophosphate is 0.3 or less, side reactions due to surplus tetravinylsilane are caused to prevent the resistance of the battery from increasing and the cycle life characteristics are lowered Can be prevented.
  • the weight ratio of tetravinylsilane is 0.05 or more, the gas generation reduction effect and the SEI film formation stabilization effect can be obtained.
  • the weight ratio of the compound containing one sulfonate group or sulfate group to the lithium difluorophosphate is 2 or less, a stabilizing effect upon formation of the SEI film can be ensured and high-temperature storage characteristics and cycle life characteristics can be improved .
  • the weight ratio of the one sulfonate group or the sulfate group-containing compound is 0.5 or more, it is possible to improve the stability of the SEI film and suppress the electrolyte side reaction without increasing the resistance.
  • the additive is contained in an amount of 1 to 18 wt%, specifically 8 to 10 wt% based on the total weight of the nonaqueous electrolyte solution for a lithium secondary battery .
  • the content of the additive is 1 wt% or more, it is possible to form a stable (SEI) coating on the surface of the negative electrode, and to prevent decomposition of the electrolyte due to reaction between the electrolyte and the negative electrode, The expected effect can be met.
  • SEI stable
  • the solubility and wettability may deteriorate as the viscosity of the non-aqueous electrolyte increases due to the excess amount of the additive, resulting in degradation of output characteristics and cycle life characteristics.
  • lithium ions from the lithium metal oxide used as an anode migrate to a carbon (crystalline or amorphous) electrode used as a cathode and are intercalated into the carbon of the cathode.
  • a carbon (crystalline or amorphous) electrode used as a cathode used as a cathode and is intercalated into the carbon of the cathode.
  • an organic material and Li 2 CO 3 , Li 2 O, LiOH, etc. are formed by reacting with the carbon-based anode, and these form an SEI film on the surface of the cathode.
  • the SEI film will prevent the reaction between the lithium ion and the carbon-based anode or other materials during repeated charging and discharging by the use of the battery, and serves as an ion tunnel through which only lithium ions pass between the electrolyte and the cathode . Due to the ion tunneling effect, the SEI film prevents the migration of organic solvents, such as EC, DMC, DEC, PP, etc., having a large molecular weight to the carbonaceous cathode, co-decomposition of the structure of the carbon-based anode. That is, once the film is formed, the lithium ions do not react with the carbonaceous anode or other materials, and thereby the amount of lithium ions can be reversibly maintained at the time of charge / discharge by the use of the battery.
  • organic solvents such as EC, DMC, DEC, PP, etc.
  • the carbon material of the negative electrode reacts with the electrolytic solution at the time of initial charging to form a passivation layer on the surface of the negative electrode so as to maintain stable charging / discharging without further decomposition of the electrolytic solution.
  • the amount of charge consumed in the layer formation is irreversible capacity, which is characterized in that it does not react reversibly during discharging. For this reason, the lithium ion battery can maintain a stable life cycle without any irreversible reaction after the initial charging reaction .
  • the lithium ion battery when the lithium ion battery is stored at a high temperature (for example, at a temperature of 60 ° C after being charged at a temperature of 4.15 V or more at 100%) in a fully charged state, the SEI film gradually degrades due to increased electrochemical energy and thermal energy over time .
  • a high temperature for example, at a temperature of 60 ° C after being charged at a temperature of 4.15 V or more at 100%
  • Such SEI film breakdown exposes the surface of the negative electrode, and the exposed negative electrode surface is decomposed while the carbonate-based solvent in the electrolyte is reacted to cause continuous side reaction.
  • the main gases produced are CO, CO 2 , CH 4 , C 2 H 6, etc., depending on the type of carbonate used and the kind of negative active material used. Regardless of the type, continuous gas evolution at high temperatures causes the cell internal pressure of the lithium ion battery to rise, causing the cell thickness to expand.
  • the nonaqueous electrolyte solution for a lithium secondary battery of the present invention includes a mixed additive in which lithium difluorophosphate, fluorobenzene, tetravinylsilane and one sulfonate group or a compound containing a sulfate group are mixed in a specific ratio, It is possible to improve the overall performance such as high-temperature storage characteristics and lifetime characteristics of the lithium secondary battery by suppressing the electrolyte side reaction during high-temperature storage as well as improving the low-temperature output characteristics by forming a more stable and solid SEI film on the surface of the negative electrode .
  • the non-aqueous electrolyte according to an embodiment of the present invention may be used together with the above-mentioned mixed additive to form a stable coating on the surface of the negative electrode and the positive electrode,
  • An additional additive capable of suppressing the decomposition of the solvent in the electrolyte solution and serving as a complementary agent for improving the mobility of the lithium ion may be further included.
  • Such an additive is not particularly limited as long as it is an additive for forming an SEI film capable of forming a stable film on the surfaces of the anode and the cathode.
  • the SEI film forming additive includes at least one SEI film selected from the group consisting of a halogen-substituted carbonate compound, a nitrile compound, a cyclic carbonate compound, a phosphate compound, a borate compound and a lithium salt compound And a second additive for forming the first additive.
  • the halogen-substituted carbonate compound is fluoroethylene carbonate (FEC)), and may be contained in an amount of 5% by weight 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.
  • nitrile compound when used together with the above-mentioned mixed additive, effects such as improvement in high-temperature characteristics can be expected by stabilizing the positive / negative electrode coating.
  • it can serve as a complement in forming the negative electrode SEI coating, can play a role of inhibiting the decomposition of the solvent in the electrolyte, and can improve the mobility of lithium ions.
  • Such a 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.
  • the carbonate-based compound forms a stable SEI film mainly on the surface of the negative electrode at the time of battery activation, thereby improving the durability of the battery.
  • the cyclic carbonate-based compound may be vinylene carbonate (VC) or vinylethylene carbonate.
  • the cyclic carbonate-based compound may include up to 3% by weight based on the total weight of the non-aqueous electrolyte. When the content of the cyclic carbonate compound in the nonaqueous electrolyte solution exceeds 3% by weight, the cell swelling inhibition performance and initial resistance may be deteriorated.
  • phosphate-based compounds include, but are not limited to, difluoro (bisoxalato) phosphate (LiDFOP), tetramethyltrimethylsilyl phosphate (LiTFOP), trimethylsilylphosphite (TMSPi), tris (2,2,2-trifluoroethyl) phosphate (TFEPa) and tris (trifluoroethyl) phosphite (TFEPi), and may be contained in an amount of 3% by weight or less based on the total weight of the nonaqueous electrolyte solution.
  • the borate compound promotes ion-pair separation of the lithium salt, improves the mobility of lithium ions, can lower the interfacial resistance of the SEI film, and can be used for a material such as LiF By dissociation, problems such as generation of hydrofluoric acid gas can be solved.
  • a borate compound include lithium foroxylate borate (LiBOB, LiB (C 2 O 4 ) 2 ), lithium oxalyl difluoroborate or tetramethyltrimethylsilylborate (TMSB), and based on the total weight of the non- 3% by weight or less.
  • the lithium salt compound may be at least one compound selected from the group consisting of LiODFB and LiBF 4 , which is different from the lithium salt contained in the non-aqueous electrolyte.
  • the lithium salt compound may be contained in an amount of not more than 3% by weight based on the total weight of the non- .
  • the first additives for forming the SEI film may be used in combination of two or more, and may be contained in an amount of 10 wt% or less, specifically 0.01 wt% to 10 wt%, preferably 0.1 wt% to 5.0 wt% based on the total amount of the electrolytic solution .
  • the content of the first additive for SEI film formation is less than 0.01% by weight, the high-temperature storage characteristics and gas reduction effect to be realized from the additive are insignificant. If the content of the first additive for SEI film formation exceeds 10% by weight There is a possibility that a side reaction in the electrolytic solution occurs excessively during charging and discharging of the battery. In particular, when the first additive for SEI film formation is added in an excessive amount, it can not be decomposed sufficiently and may be present in the electrolyte solution at room temperature without being reacted or precipitated. As a result, the resistance increases and the lifetime characteristics of the secondary battery may be deteriorated.
  • the nonaqueous electrolyte solution for a lithium secondary battery may include diphenyl disulfide (DPDS), di-p-tolyl disulfide (DTDS), and bis (4- Methoxyphenyl) disulfide (BMPDS) as a second additive for forming at least one SEI film.
  • DPDS diphenyl disulfide
  • DTDS di-p-tolyl disulfide
  • BMPDS bis (4- Methoxyphenyl) disulfide
  • the second additive for forming the SEI film contributes to the formation of a stable protective film on the surface of the negative electrode carbon material.
  • This protective film maintains a stable state even if charge and discharge are repeated.
  • the non-aqueous solvent in the electrolytic solution is electrochemically reduced and gas generation is suppressed.
  • peeling of the negative electrode carbon material from the negative electrode can be suppressed and the cycle characteristics can be improved.
  • DPDS, DTDS, and BMPDS act on the polar terminal end of PVDF and P (VDF-HFP), which are the binders, of the reaction product of the nonaqueous solvent and the carbonaceous anode at the time of forming the protective film, and the swelling of the binder by the non- And the adhesion between the electrode materials is maintained.
  • VDF-HFP the binders
  • the second additive for forming the SEI film may be contained in an amount of 0.6 wt% or less, specifically 0.1 wt% to 0.6 wt%, based on the total weight of the nonaqueous electrolyte solution for a lithium secondary battery. If the content of the additive is 0.1% by weight or more, the effect to be achieved from the additive can be obtained. When the additive is 0.6% by weight or less, a side reaction due to a surplus additive can be prevented.
  • a lithium secondary battery comprising a negative electrode, a positive electrode, a separator interposed between the negative electrode and the positive electrode, and a nonaqueous electrolyte
  • the nonaqueous electrolyte solution provides a lithium secondary battery comprising the nonaqueous electrolyte solution of the present invention.
  • the anode may include a lithium-nickel-manganese-cobalt oxide as a cathode active material.
  • the positive electrode, the negative electrode, and the separator interposed between the positive electrode and the negative electrode are sequentially laminated to form an electrode assembly.
  • the positive electrode, negative electrode, And those used in the production of lithium secondary batteries can all be used.
  • the positive electrode may be produced by forming a positive electrode mixture layer on the positive electrode 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.
  • Li (Ni p Co q Mn r 1 ) O 2 for example, Li (Ni p Co q Mn r 1 ) O 2
  • the positive electrode active material that is a typical example Li (Ni 1/3 Mn 1/3 Co 1/3 ) O 2, Li (Ni 0.35 Mn 0.28 Co 0.37) 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 .
  • LiMnO 2 , LiMn 2 O 4, etc. a lithium-cobalt oxide (for example, LiCoO 2, etc.) in addition to the lithium-nickel-manganese-cobalt oxide, Lithium-nickel-based oxides such as LiNiO 2 , lithium-nickel-manganese-based oxides such as LiNi 1 -Y Mn Y O 2 (where 0 ⁇ Y ⁇ 1), LiMn 2-z Ni z O 4 (where, 0 ⁇ Z ⁇ 2) and the like), lithium-nickel-cobalt oxide (e.g., LiNi 1-Y1 Co Y1 O 2 (here, 0 ⁇ Y1 ⁇ 1), etc.), lithium-manganese-cobalt oxide (e.
  • M lithium-nickel-cobalt-transition metal oxide
  • Such a cathode active material may be LiCoO 2 , LiMnO 2 , LiNiO 2 , or lithium nickel cobalt aluminum oxide (for example, Li (Ni 0.8 Co 0.15 Al 0.05 ) O 2, etc.).
  • the positive electrode active material may include 90 wt% to 99 wt%, specifically 93 wt% to 98 wt%, based on the total weight of the solid content in the positive electrode 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
  • the conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery.
  • the conductive material may be carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, Carbon powder; Graphite powder such as natural graphite, artificial graphite, or graphite with a highly developed crystal structure; 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 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 negative electrode may be manufactured by forming a negative electrode mixture layer on the negative electrode collector.
  • the negative electrode material 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 a 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, lithium capable of doping and dedoping lithium Materials, and transition metal oxide transition metal oxides.
  • 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.
  • the metal or an alloy of these metals and lithium may be selected from the group consisting of Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, And Sn, or an alloy of these metals and lithium may be used.
  • metal composite oxide is 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 x WO 2 (0? X? 1), and Sn x Me 1-x Me y y z , Pb, Ge, Me ': Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, Halogen: 0 ⁇ x? 1; 1? Y? May be used.
  • 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, Ti, Ge, P, As, Sb, Se, 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.
  • a conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, for example, graphite such as natural graphite or artificial graphite; Carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; 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 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.
  • a conventional porous polymer film conventionally used as a separator for example, a polyolefin such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, and an ethylene / methacrylate copolymer
  • a porous polymer film made of a high molecular weight polymer may be used alone or in a laminated manner, or a nonwoven fabric made of a conventional porous nonwoven fabric such as a glass fiber having a high melting point, a polyethylene terephthalate fiber or the like may be used. It is not.
  • 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.
  • LiDFP Lithium difluorophosphate
  • FB Fluorobenzene
  • TVS tetravinylsilane
  • PS 1,3-propane sultone
  • a negative active material Li (Ni 0.6 Mn 0.2 Co 0.2 ) O 2
  • a conductive material carbon black
  • a binder polyvinylidene fluoride
  • a negative electrode active material slurry (solid concentration: 60% by weight) was prepared by adding a negative electrode active material (artificial graphite), a binder (PVDF), and a conductive material (carbon black) to NMP as a solvent at a weight ratio of 95: 2: 3.
  • the negative electrode active material slurry was coated on a negative electrode current collector (Cu thin film) having a thickness of 90 ⁇ , dried, and rolled to produce a negative electrode.
  • the positive electrode and the negative electrode prepared by the above-mentioned method were sequentially laminated together with a polyethylene porous film to prepare an electrode assembly, which was then placed in a battery case, the nonaqueous electrolyte was injected, and the battery was sealed to manufacture a lithium secondary battery.
  • Example 2 In the same manner as in Example 1 except that 5.4 g of a mixed additive obtained by mixing LiDFP: FB: TVS: PS in an amount of 1: 2: 0.1: 1.5 by weight as an additive was added to 94.6 g of a solvent during the preparation of the non- To prepare a nonaqueous electrolyte of the present invention and a secondary battery comprising the same (see Table 1 below).
  • Example 1 In the same manner as in Example 1 except that 11.3 g of a mixed additive obtained by mixing LiDFP: FB: TVS: PS in an amount of 1: 8: 0.3: 2 by weight as an additive was added to 88.7 g of a solvent during the preparation of the non- To prepare a nonaqueous electrolyte of the present invention and a secondary battery comprising the same (see Table 1 below).
  • Example 2 In the same manner as in Example 1 except for adding, to the 83.05 g of the solvent, 16.95 g of a mixed additive obtained by mixing LiDFP: FB: TVS: PS in a weight ratio of 1: 8: 0.3: To prepare a nonaqueous electrolyte of the present invention and a secondary battery comprising the same (see Table 1 below).
  • Example 1 The procedure of Example 1 was repeated except for adding 16.95 g of a mixed additive obtained by mixing 83.05 g of a solvent with LiDFP: FB: TVS: PS: TMS in a weight ratio of 1: 8: 0.3:
  • the non-aqueous electrolyte of the present invention and a secondary battery containing the same were prepared (see Table 1 below).
  • a nonaqueous electrolytic solution and a secondary battery including the nonaqueous electrolytic solution were prepared in the same manner as in Example 1 except that only 3 g of vinylene carbonate was added as an additive to 97 g of a solvent in the preparation of the nonaqueous electrolyte (see Table 2 below).
  • a non-aqueous electrolyte and a secondary battery containing the non-aqueous electrolyte were prepared in the same manner as in Example 1 except that only 2 g of LiBF 4 was added as an additive to 98 g of a solvent in the preparation of the non-aqueous electrolyte (see Table 2 below).
  • Example 2 In the same manner as in Example 1, except that 9 g of a mixed additive in which LiDFP: FB: TVS: PS was mixed at a weight ratio of 1: 6: 0.5: 1.5 as an additive was added to 91 g of a solvent at the time of preparing the non-aqueous electrolyte, To prepare an electrolytic solution and a secondary battery containing the electrolytic solution (see Table 2 below).
  • Aqueous electrolyte solution was prepared in the same manner as in Example 1, except that 8.2 g of a mixed additive obtained by mixing FB: TVS: PS at a weight ratio of 6: 0.2: 2 as an additive in 91.8 g of a solvent was added. And a secondary battery containing the same was prepared (see Table 2 below).
  • Aqueous electrolyte solution was prepared in the same manner as in Example 1, except that 5.2 g of a mixed additive obtained by mixing 94.8 g of a solvent with LiDFP: TVS: PS at a weight ratio of 2: 0.2: 3 as an additive was added. And a secondary battery containing the same was prepared (see Table 2 below).
  • Aqueous electrolyte solution was prepared in the same manner as in Example 1, except that 8.5 g of a mixed additive in which LiDFP: FB: PS was mixed at a weight ratio of 1: 6: 1.5 as an additive was added to 91.5 g of a solvent at the time of preparing the non- And a secondary battery containing the same was prepared (see Table 2 below).
  • Aqueous electrolyte solution was prepared in the same manner as in Example 1, except that 7.2 g of a mixed additive obtained by mixing LiDFP: FB: TVS in an amount of 1: 6: 0.2 by weight as an additive in 92.8 g of a solvent was added. And a secondary battery containing the same was prepared (see Table 2 below).
  • Example 2 The procedure of Example 1 was repeated except that 2.15 g of a mixed additive prepared by mixing 97.85 g of a solvent with LiDFP: FB: TVS: TMS in a weight ratio of 0.9: 8: 0.3: 2 as an additive was added during the preparation of the non- To prepare a nonaqueous electrolyte and a secondary battery containing the same (see Table 2 below).
  • Example 2 In the same manner as in Example 1 except that 3.5 g of a mixed additive in which LiDFP: FB: TVS: PS was mixed at a weight ratio of 1: 6: 0.2: 0.4 as an additive was added to 96.5 g of a solvent at the time of preparing the non- To prepare a nonaqueous electrolyte and a secondary battery containing the same (see Table 2 below).
  • Each of the lithium secondary batteries prepared in Examples 1 and 4 and Comparative Example 1 and Comparative Example 4 was charged at a constant voltage of 0.33 C / 4.25 V constant current-constant voltage 4.25 V / 0.05 C condition and discharging SOC 50% at a constant current of 0.33C to adjust the charged state of the battery.
  • Each of the secondary batteries was allowed to stand for 4 hours or more at -30 ° C for temperature equilibrium, and then the voltage drop was measured in a state where a discharge pulse was applied for 30 seconds at a power of 3W to 7W.
  • the SOC setting and the evaluation of the output power at low temperature were conducted using a PNE-0506 charge / discharge device (PNE solution, 5V, 6A, manufactured by the company).
  • the output characteristics at low temperature for each secondary battery are calculated using the obtained falling voltage value, and are shown in Fig.
  • the voltage drop of the lithium secondary battery including the non-aqueous electrolyte according to the first and fourth embodiments of the present invention is smaller than that of the lithium secondary batteries of Comparative Examples 1 and 4 . From these results, it can be confirmed that the low-temperature output characteristics are excellent.
  • the lithium secondary batteries prepared in Examples 1 to 15 and the lithium secondary batteries prepared in Comparative Examples 1 to 13 were respectively charged at a constant current / constant voltage (CC / CV) of 4.25 V / 0.05 C And discharged at a constant current of 0.33C / 3.0V.
  • the initial discharge capacity was defined as the discharge capacity measured by using a PNE-0506 charge / discharge device (manufactured by PNE Co., Ltd., 5V, 6A) prior to cell assembly / high temperature storage.
  • Each lithium secondary battery was set to a SOC 100% charged state and stored at 60 ⁇ ⁇ for 16 weeks.
  • the battery was charged at a constant current / constant voltage (CC / CV) of 4.25 V / 0.05 C at 25 ° C and discharged at a constant current of 0.33 C / 3.0 V, and charged in a PNE-0506 charge / discharge device Solution, 5V, 6A) was used to measure the discharge capacity.
  • the measured discharge capacity was defined as discharge capacity after high temperature storage.
  • Capacity retention rate (%) (discharge capacity after high-temperature storage / initial discharge capacity) x 100
  • the lithium secondary batteries prepared in Examples 1 to 15 and the lithium secondary batteries prepared in Comparative Examples 1 to 13 were respectively discharged at a constant current of 0.33 C at 25 DEG C for an SOC of 50%
  • the output of each lithium secondary battery was measured through a voltage drop at a constant current (CC) condition of 2.5 V and a discharge pulse for 30 seconds at 2.5C.
  • the discharge output value measured using a PNE-0506 charge / discharge device was defined as an initial discharge output after cell assembly / high temperature storage.
  • Each lithium secondary battery was set to a SOC 100% charged state and stored at 60 ⁇ ⁇ for 16 weeks.
  • the battery was charged at a constant current / constant voltage (CC / CV) of 4.25 V / 0.05 C at 25 ° C and discharged at a constant current of 0.33 C / 3.0 V, and charged in a PNE-0506 charge / discharge device Solution, 5V, 6A) was used to measure the discharge output value.
  • the measured discharge output value was defined as discharge output value after storing at high temperature.
  • the lithium secondary batteries manufactured in Examples 1 to 15 and the lithium secondary batteries prepared in Comparative Examples 1 to 13 were respectively driven at a voltage of 3.0 V to 4.25 V at 25 ⁇ in a voltage driving range of 0.33 C / 4.25 V constant current - constant voltage 4.25 V / 0.05C, and the thickness of each secondary cell was measured with a plate thickness meter (Mitutoyo (Japan)) under SOC 100% condition.
  • the initial thickness measured after cell assembly is defined as the initial thickness
  • the initial charge and discharge of the rechargeable lithium secondary batteries were charged to 4.2 V of SOC up to 100%, stored at 60 DEG C for 16 weeks, cooled at room temperature, and then stored at a high temperature using a plate thickness meter (Mitutoyo, The thickness was measured.
  • Thickness increase rate (%) ⁇ (thickness after high temperature storage - initial thickness) / initial thickness ⁇ x 100
  • the lithium secondary batteries prepared in Examples 1 to 15 and the lithium secondary batteries prepared in Comparative Examples 1 to 13 were respectively charged at 25 DEG C at 45 DEG C and at a constant current / constant voltage (CC / CV) of 4.25 V /0.05C and discharged at a constant current of 0.33C / 3.0V.
  • the charging and discharging was performed in one cycle, and the charging and discharging was repeated 500 times.
  • cycle life characteristic (%) (500 cycle capacity / one cycle capacity) x 100
  • PS means 1,3-propane sultone
  • PRS means 1,3-propanesultone
  • TMS means trimethylene sulfate
  • ESa means ethylene sulfate.
  • MMDS means methylene methane disulfonate.
  • the lithium secondary battery having the non-aqueous electrolyte containing the mixed additives of Examples 1 to 14 had a capacity retention rate of 79.1% or more after high temperature storage, an output characteristic of 81.9%
  • the cycle life characteristics are all significantly improved.
  • Example 7 Comparing the lithium secondary batteries of Example 7 and Comparative Example 7 in which addition of fluorobenzene was different among the additive components, the battery of Comparative Example 7 was ignited during overcharging, whereas in Example 7 Of the lithium secondary battery can not be ignited during overcharging while maintaining the capacity retention rate, output characteristics, cell thickness increase rate, and high temperature cycle life characteristics after high temperature storage.
  • the lithium secondary battery of Example 7 is superior to the lithium secondary battery of Comparative Example 8 by addition of tetravinylsilane It can be seen that exceptionally good capacity retention, output characteristics and cycle life characteristics are realized except for the cell thickness increase rate after high temperature storage.
  • the lithium secondary battery exhibits excellent capacity and output characteristics and cycle life characteristics at a high temperature, which is superior to that of the lithium secondary battery, and exhibits an excellent effect of suppressing the cell thickness increase.
  • the lithium secondary batteries of Examples 1 to 14 having the non- The capacity retention rate, the output characteristics, and the cycle life characteristics are all degraded.
  • the lithium secondary battery manufactured in Example 1 and the lithium secondary battery manufactured in Comparative Example 7 were each subjected to a SOC 100% state at 25 ⁇ ⁇ using a PNE-0506 charge / discharge device (PNE solution, 5V, 6A, 0.33C / 4.25V constant current / constant voltage (CC / CV) conditions. Thereafter, overcharging was carried out with a correct current of 0.33C up to 6.4 V, and the change of temperature and voltage of the battery was measured to confirm whether or not the battery was ignited.
  • the results of the lithium secondary battery of Example 1 are shown in FIG. 2, and the results of the lithium secondary battery of Comparative Example 7 are shown in FIG.
  • the voltage was found to be 5.0 V or less in the range of 7 to 22 minutes, while fluorobenzene It is found that the voltage of the lithium secondary battery of Comparative Example 7 (see FIG. 3) provided with the nonaqueous electrolyte solution which does not react with the nonaqueous electrolyte solution rose to 5.2 V around 25 minutes.
  • the fluorobenzene reacts with the corresponding voltage band to decompose, thereby suppressing the additional reaction between the battery and the electrolyte, thereby preventing overcharge of the battery.
  • ignition is suppressed by significantly preventing the electrolyte depletion and lithium precipitation due to the temperature increase of the battery and the additional overcharge.

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Abstract

La présente invention concerne un électrolyte non aqueux pour une batterie secondaire au lithium et une batterie secondaire au lithium le comprenant et, spécifiquement, un électrolyte non aqueux pour une batterie secondaire au lithium, l'électrolyte non aqueux comprenant : un sel de lithium ; un solvant organique ; et un additif, l'additif étant un additif de mélange comprenant du difluorophosphate de lithium, du fluorobenzène, du tétravinyl silane et un composé contenant un groupe sulfonate ou un groupe sulfate selon un rapport pondéral de 1 : 2-8 : 0,05-0,3 : 0,5-2, et une batterie secondaire au lithium le comprenant.
PCT/KR2018/013783 2017-11-13 2018-11-13 Électrolyte non aqueux pour batterie secondaire au lithium et batterie secondaire au lithium le comprenant WO2019093853A1 (fr)

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EP18875224.0A EP3648231B1 (fr) 2017-11-13 2018-11-13 Électrolyte non aqueux pour batterie secondaire au lithium et batterie secondaire au lithium le comprenant
CN201880050190.4A CN111052485B (zh) 2017-11-13 2018-11-13 用于锂二次电池的非水性电解液和包含其的锂二次电池
PL18875224T PL3648231T3 (pl) 2017-11-13 2018-11-13 Niewodny elektrolit dla akumulatora litowego i zawierający go akumulator litowy
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CN112687956A (zh) * 2020-12-28 2021-04-20 远景动力技术(江苏)有限公司 锂电池的非水电解液及基于其的锂离子电池
CN113517471A (zh) * 2021-05-18 2021-10-19 中节能万润股份有限公司 一种锂离子电池非水电解液及其应用
CN114024034A (zh) * 2021-10-25 2022-02-08 珠海冠宇电池股份有限公司 一种电池
CN114649589A (zh) * 2020-12-18 2022-06-21 张家港市国泰华荣化工新材料有限公司 一种电解液及锂二次电池
CN116848688A (zh) * 2023-02-20 2023-10-03 宁德时代新能源科技股份有限公司 非水电解质溶液及其锂二次电池和用电装置

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