WO2018088743A1 - 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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WO2018088743A1
WO2018088743A1 PCT/KR2017/012092 KR2017012092W WO2018088743A1 WO 2018088743 A1 WO2018088743 A1 WO 2018088743A1 KR 2017012092 W KR2017012092 W KR 2017012092W WO 2018088743 A1 WO2018088743 A1 WO 2018088743A1
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electrolyte
additive
formula
secondary battery
lithium secondary
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PCT/KR2017/012092
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English (en)
Korean (ko)
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최현봉
김애란
신우철
신정민
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삼성에스디아이 주식회사
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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
    • H01M10/056—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
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic 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

  • It relates to an electrolyte for a lithium secondary battery and a lithium secondary battery comprising the same.
  • Lithium secondary batteries are attracting attention as power sources for various electronic devices due to their high discharge voltage and high energy density.
  • lithium and a transition metal having a structure capable of intercalating lithium ions such as LiCoO 2 , LiMn 2 O 4 , LiNi 1 - x Co x O 2 (0 ⁇ x ⁇ 1), etc. Oxides are mainly used.
  • the negative electrode active material various types of carbon-based materials including artificial, natural graphite, and hard carbon capable of inserting / desorbing lithium are mainly used.
  • an organic solvent in which lithium salt is dissolved is used as an electrolyte of a lithium secondary battery.
  • propane sultone is being applied as an additive to the electrolyte, but propane sultone may cause cancer, and since it is currently a regulated substance, its amount may be less than 0.1 wt% based on the total weight of the battery. In this content, sufficient gas generation suppression effect cannot be obtained.
  • One embodiment is to provide a high-capacity, long life and high output power, harmless electrolyte for a lithium secondary battery.
  • Another embodiment is to provide a lithium secondary battery including the electrolyte.
  • a non-aqueous organic solvent Lithium salts; And it provides an electrolyte for a lithium secondary battery comprising a first additive comprising at least one of the compounds represented by the following formula (1).
  • X is O, S or CR a R b , and R a and R b are each independently hydrogen; Or a substituted or unsubstituted alkyl group,
  • Y is O, S or CR c R d , and R c and R d are each independently hydrogen; Substituted or unsubstituted alkyl group; Or a substituted or unsubstituted alkenyl group,
  • R 10 , R 11 , R 12 , R 13 , R 14 and R 15 are each independently hydrogen; Substituted or unsubstituted alkyl group; Or a substituted or unsubstituted alkenyl group,
  • n 1 and n 2 are each independently an integer of 1 to 3)
  • the content of the first additive may be 0.1 wt% to 10 wt%, and 0.5 wt% to 3 wt% with respect to the total weight of the electrolyte.
  • the first additive may be represented by Chemical Formula 1.
  • the electrolyte may further include a second additive represented by Formula 5 below.
  • X 1 is CR e R f , and R e and R f are each independently hydrogen; Or a substituted or unsubstituted alkyl group,
  • Z 1 and Z 2 are independently of each other hydrogen; Substituted or unsubstituted alkyl group; Or vinyl
  • Z 3 is hydrogen; Or a substituted or unsubstituted alkyl group,
  • n 3 is an integer from 1 to 3)
  • the content of the second additive may be 0.1 wt% to 10 wt% with respect to the total weight of the electrolyte.
  • the weight ratio of the first additive and the second additive may be 1: 1 to 1:10 weight ratio.
  • the electrolyte may further include a third additive which is fluoroethylene carbonate, vinylethylene carbonate, succinonitrile, hexane tricyanide, LiBF 4, or a combination thereof.
  • a third additive which is fluoroethylene carbonate, vinylethylene carbonate, succinonitrile, hexane tricyanide, LiBF 4, or a combination thereof.
  • Another embodiment of the present invention is a negative electrode including a negative electrode active material; A positive electrode including a positive electrode active material; And it provides a lithium secondary battery comprising a non-aqueous organic solvent, a lithium salt and the electrolyte.
  • the electrolyte for a lithium secondary battery according to one embodiment of the present invention may improve charge / discharge characteristics and increase a start temperature of a positive electrode interface reaction.
  • FIG. 1 is a view briefly showing a lithium secondary battery according to an embodiment of the present invention.
  • Figure 2a is a graph showing the CV (cyclic voltammetry) results of the additive solution containing the first additive prepared in Preparation Example 3.
  • FIG. 2B is an enlarged view of FIG. 2A.
  • FIG. 3 is a graph showing CV results of a reference solution of a mixed solvent of ethylene carbonate, ethylmethyl carbonate, and dimethyl carbonate in which 1.5M LiPF 6 is dissolved.
  • Figure 4 is a graph showing the LSV (linear sweep voltammetry) results at room temperature of the additive solution and the reference solution.
  • Figure 5 is a graph showing the measurement of the resistance before and after the high temperature storage (A) and high temperature storage (B) of the battery prepared according to Example 1 and Comparative Examples 1 and 2.
  • Figure 6 is a graph showing the measurement of the thickness increase rate after high temperature storage of the battery prepared according to Example 1 and Comparative Examples 1 and 2.
  • One embodiment of the invention is a non-aqueous organic solvent; Lithium salts; And it provides an electrolyte for a lithium secondary battery comprising a first additive comprising at least one of the compounds represented by the following formula (1).
  • X is O, S or CR a R b , and R a and R b are each independently hydrogen; Or a substituted or unsubstituted alkyl group,
  • Y is O, S or CR c R d , and R c and R d are each independently hydrogen; Substituted or unsubstituted alkyl group; Or a substituted or unsubstituted alkenyl group,
  • R 10 , R 11 , R 12 , R 13 , R 14 and R 15 are each independently hydrogen; A substituted or unsubstituted alkyl group,
  • n 1 and n 2 are each independently an integer of 1 to 3;
  • the alkyl group or alkenyl group may be C1 to C10, may be C1 to C3.
  • the alkyl group may be linear or branched.
  • the substituents can be halogen, such as fluoro.
  • the first additive may be represented by the formula (1).
  • the first additive may effectively suppress the generation of gas that may be generated during charging and discharging of the battery or at high temperature storage, and also may effectively suppress an increase in resistance.
  • the first additive includes a cyclopropane functional group, as represented by Chemical Formulas 1 to 4, and the cyclopropane functional group is reduced and decomposed to form a vinyl group during charging and discharging or at high temperature storage, and the vinyl group is polymerized. (polymerization) forms a solid film (SEI film) on the surface of the cathode, and as the film is formed on the surface of the cathode can suppress the breakdown of the solid electrolyte interface (SEI) film of the cathode, thereby suppressing gas generation have.
  • SEI film solid film
  • the first additive may include a SO 2 or CO functional group, as represented by Chemical Formulas 1 to 4, and according to the functional group, a high heat-resistant rigid film (SEI film) may be formed during high temperature storage, and thus, high temperature storage. This can suppress the problem of increased resistance.
  • SO 2 or CO functional group as represented by Chemical Formulas 1 to 4
  • SEI film high heat-resistant rigid film
  • the first additive is a compound that is harmless to the human body, it may be appropriately used in actual battery manufacturing.
  • the content of the first additive may be 0.1 wt% to 10 wt%, and 0.5 wt% to 3 wt% with respect to the total weight of the electrolyte.
  • the content of the first additive is included in the above range, suppression of gas generation and increase in resistance can be effectively obtained.
  • the electrolyte may further include a second additive represented by the following formula (5).
  • X 1 is CR e R f , and R e and R f are each independently hydrogen; A substituted or unsubstituted alkyl group,
  • Z 1 , Z 2 , and Z 3 are independently of each other hydrogen; A substituted or unsubstituted alkyl group,
  • n 3 is an integer of 1 to 3.
  • the carbon number of the alkyl group or alkenyl group or vinyl group may be C1 to C10, may be C1 to C3.
  • the alkyl group may be linear or branched.
  • the substituents can be halogen, such as fluoro.
  • the second additive may be present in an amount of about 0.1 wt% to about 5 wt%, and about 1 wt% to about 3 wt% based on the total weight of the electrolyte.
  • the content of the second additive is included in the above range, it is possible to effectively suppress that the resistance inside the battery is increased.
  • the weight ratio of the first additive and the second additive may be in a 1: 1 weight ratio to 1:10 weight ratio, and may be in a 1: 1 weight ratio to 1: 3 weight ratio.
  • the mixing ratio of the first additive and the second additive is included in the above range, the high temperature cycle life characteristics are more excellent and the gas generation reducing effect is more excellent.
  • the electrolyte may further include a third additive which is fluoroethylene carbonate, vinylene carbonate, vinylethylene carbonate, succinonitrile, hexane tricyanide, LiBF 4, or a combination thereof.
  • a third additive which is fluoroethylene carbonate, vinylene carbonate, vinylethylene carbonate, succinonitrile, hexane tricyanide, LiBF 4, or a combination thereof.
  • the content of the third additive may be 1% to 3% by weight based on the total weight of the electrolyte.
  • the third additive is used in the amount in the above range, the battery resistance can be suppressed more effectively. If the third additive is used in excess of the content, the battery resistance is remarkably increased, and the cycle life characteristics drop sharply, which is not appropriate.
  • the non-aqueous organic solvent serves as a medium through which ions involved in the electrochemical reaction of the cell can move.
  • non-aqueous organic solvent a carbonate-based, ester-based, ether-based, ketone-based, alcohol-based, or aprotic solvent may be used.
  • Examples of the carbonate solvent include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methylethyl carbonate (MEC), and ethylene carbonate ( EC), propylene carbonate (PC), butylene carbonate (BC) and the like can be used.
  • DMC dimethyl carbonate
  • DEC diethyl carbonate
  • DPC dipropyl carbonate
  • MPC methylpropyl carbonate
  • EPC ethylpropyl carbonate
  • MEC methylethyl carbonate
  • EC ethylene carbonate
  • PC propylene carbonate
  • BC butylene carbonate
  • ester solvent methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, propyl propionate, ⁇ -butyrolactone, decanolide, valero Lactone, mevalonolactone, caprolactone and the like can be used.
  • Dibutyl ether, tetraglyme, diglyme, dimethoxyethane, 2-methyltetrahydrofuran, tetrahydrofuran may be used as the ether solvent, and cyclohexanone may be used as the ketone solvent.
  • Ethyl alcohol, isopropyl alcohol, etc. may be used as the alcohol solvent, and as the aprotic solvent, T-CN (T is a linear, branched, or cyclic hydrocarbon group having 2 to 20 carbon atoms, Nitriles such as double bond aromatic rings or ether bonds), amides such as dimethylformamide, dioxolanes such as 1,3-dioxolane, sulfolane, and the like.
  • T-CN T is a linear, branched, or cyclic hydrocarbon group having 2 to 20 carbon atoms, Nitriles such as double bond aromatic rings or ether bonds
  • amides such as dimethylformamide
  • dioxolanes such as 1,3-dioxolane, sulfolane, and the like.
  • the non-aqueous organic solvent may be used alone or in admixture of one or more.
  • the mixing ratio in the case of mixing more than one can be appropriately adjusted according to the desired cell performance, which can be widely understood by those skilled in the art.
  • the carbonate solvent it is preferable to use a mixture of a cyclic carbonate and a chain carbonate.
  • the cyclic carbonate and the chain carbonate may be mixed and used in a volume ratio of 1: 1 to 1: 9, so that the performance of the electrolyte may be excellent.
  • the non-aqueous organic solvent may further include an aromatic hydrocarbon organic solvent in the carbonate solvent.
  • the carbonate solvent and the aromatic hydrocarbon organic solvent may be mixed in a volume ratio of 1: 1 to 30: 1.
  • an aromatic hydrocarbon compound of Formula 6 may be used as the aromatic hydrocarbon-based organic solvent.
  • R 1 to R 6 are the same or different from each other and are selected from the group consisting of hydrogen, halogen, alkyl group having 1 to 10 carbon atoms, haloalkyl group, and combinations thereof.
  • aromatic hydrocarbon organic solvent examples include benzene, fluorobenzene, 1,2-difluorobenzene, 1,3-difluorobenzene, 1,4-difluorobenzene, 1,2,3-tri Fluorobenzene, 1,2,4-trifluorobenzene, chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, 1 , 2,4-trichlorobenzene, iodobenzene, 1,2-dioodobenzene, 1,3-dioiobenzene, 1,4-dioiobenzene, 1,2,3-triiodobenzene, 1, 2,4-triiodobenzene, toluene, fluorotoluene, 2,3-difluorotoluene, 2,4-difluorotol, to
  • the lithium secondary battery electrolyte may further include an ethylene carbonate-based compound of Formula 7 to improve battery life.
  • R 7 and R 8 are each independently selected from the group consisting of hydrogen, a halogen group, a cyano group (CN), a nitro group (NO 2 ) and a fluorinated C1-5 alkyl group, wherein R At least one of 7 and R 8 is selected from the group consisting of a halogen group, a cyano group (CN), a nitro group (NO 2 ) and a fluorinated alkyl group having 1 to 5 carbon atoms, provided that both R 7 and R 8 are not hydrogen; .
  • ethylene carbonate-based compound examples include difluoro ethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, cyanoethylene carbonate or fluoroethylene carbonate. Can be. In the case of further using such life improving additives, the amount thereof can be properly adjusted.
  • the lithium salt is a substance that dissolves in an organic solvent and acts as a source of lithium ions in the battery to enable the operation of a basic lithium secondary battery and to promote the movement of lithium ions between the positive electrode and the negative electrode.
  • Representative examples of such lithium salts are LiPF 6 , LiSbF 6 , LiAsF 6 , LiN (SO 2 C 2 F 5 ) 2 , Li (CF 3 SO 2 ) 2 N, LiN (SO 3 C 2 F 5 ) 2 , LiC 4 F 9 SO 3 , LiClO 4 , LiAlO 2 , LiAlCl 4 , LiN (C x F 2x + 1 SO 2 ) (C y F 2y + 1 SO 2 ), where x and y are natural numbers, for example 1 to 20 ), LiCl, LiI and LiB (C 2 O 4 ) 2 (lithium bis (oxalato) borate: LiBOB) to support one or more selected from the group consisting of
  • the lithium salt concentration is
  • Another embodiment provides a lithium secondary battery including the electrolyte, a positive electrode, and a negative electrode.
  • the positive electrode includes a current collector and a positive electrode active material layer formed on the current collector and including a positive electrode active material.
  • a cathode lithiumated intercalation compound capable of reversible intercalation and deintercalation of lithium
  • a cathode active material such as cobalt, manganese, nickel, and these
  • One or more of the complex oxides of a metal and lithium selected from the combination of More specific examples may be used a compound represented by any one of the following formula.
  • Li a A 1 -b X b D 2 (0.90 ⁇ a ⁇ 1.8, 0 ⁇ b ⁇ 0.5); Li a A 1 - b X b O 2 - c D c (0.90 ⁇ a ⁇ 1.8, 0 ⁇ b ⁇ 0.5, 0 ⁇ c ⁇ 0.05); Li a E 1 - b X b O 2 - c D c (0.90 ⁇ a ⁇ 1.8, 0 ⁇ b ⁇ 0.5, 0 ⁇ c ⁇ 0.05); Li a E 2 - b X b O 4 - c D c (0.90 ⁇ a ⁇ 1.8, 0 ⁇ b ⁇ 0.5, 0 ⁇ c ⁇ 0.05); Li a Ni 1-bc Co b X c D ⁇ (0.90 ⁇ a ⁇ 1.8, 0 ⁇ b ⁇ 0.5, 0 ⁇ c ⁇
  • A is selected from the group consisting of Ni, Co, Mn, and combinations thereof;
  • X is selected from the group consisting of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements and combinations thereof;
  • D is selected from the group consisting of O, F, S, P, and combinations thereof;
  • E is selected from Co, Mn, and combinations thereof;
  • T is selected from the group consisting of F, S, P, and combinations thereof;
  • G is selected from the group consisting of Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, and combinations thereof;
  • Q is selected from the group consisting of Ti, Mo, Mn, and combinations thereof;
  • Z is selected from the group consisting of Cr, V, Fe, Sc, Y, and combinations thereof;
  • J is selected from the group consisting of V, Cr, Mn, Co, Ni, Cu, and combinations thereof.
  • the coating layer may include at least one coating element compound selected from the group consisting of oxides of the coating elements, hydroxides of the coating elements, oxyhydroxides of the coating elements, oxycarbonates of the coating elements and hydroxycarbonates of the coating elements. Can be.
  • the compounds constituting these coating layers may be amorphous or crystalline.
  • As the coating element included in the coating layer Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr or a mixture thereof may be used.
  • the coating layer forming process may use any coating method as long as it can be coated with the above compounds by a method that does not adversely affect the physical properties of the positive electrode active material (for example, spray coating or dipping method). Detailed descriptions thereof will be omitted since they can be understood by those skilled in the art.
  • the content of the positive electrode active material may be 90% to 98% by weight based on the total weight of the positive electrode active material layer.
  • the cathode active material layer may further include a binder and a conductive material.
  • the content of the binder and the conductive material may be 1% by weight to 5% by weight based on the total weight of the positive electrode active material layer, respectively.
  • the binder adheres positively to the positive electrode active material particles, and also serves to adhere the positive electrode active material to the current collector well, and examples thereof include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, and polyvinyl. Chloride, carboxylated polyvinylchloride, polyvinylfluoride, polymer comprising ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene- Butadiene rubber, acrylic styrene-butadiene rubber, epoxy resin, nylon and the like can be used, but is not limited thereto.
  • the conductive material is used to impart conductivity to the electrode, and any battery can be used as long as it is an electron conductive material without causing chemical change in the battery.
  • the conductive material include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, and carbon fiber; Metal materials such as metal powder or metal fibers such as copper, nickel, aluminum and silver; Conductive polymers such as polyphenylene derivatives; Or a conductive material containing a mixture of these.
  • the current collector may be aluminum foil, nickel foil, or a combination thereof, but is not limited thereto.
  • the negative electrode includes a current collector and a negative electrode active material layer formed on the current collector and including a negative electrode active material.
  • the negative electrode active material a material capable of reversibly intercalating / deintercalating lithium ions, a lithium metal, an alloy of lithium metal, a material dope and dedoped lithium, or a transition metal oxide may be used.
  • Examples of a material capable of reversibly intercalating / deintercalating the lithium ions include carbon materials, that is, carbon-based negative electrode active materials generally used in lithium secondary batteries.
  • Representative examples of the carbon-based negative active material may be crystalline carbon, amorphous carbon, or a combination thereof.
  • Examples of the crystalline carbon include graphite such as amorphous, plate, flake, spherical or fibrous natural graphite or artificial graphite, and examples of the amorphous carbon include soft carbon or hard carbon ( hard carbon), mesophase pitch carbide, calcined coke, and the like.
  • alloy of the lithium metal examples include lithium and Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn. Alloys of metals selected from can be used.
  • Examples of materials that can be doped and undoped with lithium include Si, SiO x (0 ⁇ x ⁇ 2), and Si-Q alloys (wherein Q is an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, a Group 15 element, and 16).
  • Si-carbon composites, Sn, SnO 2 , Sn-R (wherein R is an alkali metal, an alkaline earth metal, 13
  • the elements Q and R include Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ge, P, As, Sb, Bi, S, Se, Te, Po, and combinations thereof may be used.
  • Lithium titanium oxide may be used as the transition metal oxide.
  • the negative electrode active material layer may include a negative electrode active material and a binder, and may further include a conductive material.
  • the content of the negative electrode active material in the negative electrode active material layer may be 95% by weight to 99% by weight with respect to the total weight of the negative electrode active material layer.
  • the content of the binder in the negative electrode active material layer may be 1% by weight to 5% by weight based on the total weight of the negative electrode active material layer.
  • 90 wt% to 98 wt% of the negative electrode active material, 1 to 5 wt% of the binder, and 1 wt% to 5 wt% of the conductive material may be used.
  • the binder adheres the anode active material particles to each other well, and also serves to adhere the anode active material to the current collector well.
  • a water-insoluble binder, a water-soluble binder or a combination thereof can be used as the binder.
  • the water-insoluble binder includes polyvinyl chloride, carboxylated polyvinylchloride, polyvinyl fluoride, polymers including ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride , Polyethylene, polypropylene, polyamideimide, polyimide, or a combination thereof.
  • water-soluble binder examples include styrene-butadiene rubber, acrylated styrene-butadiene rubber, polyvinyl alcohol, sodium polyacrylate, propylene and olefin copolymers having 2 to 8 carbon atoms, and (meth) acrylic acid and (meth) acrylic acid alkyl esters. Copolymers or combinations thereof.
  • a water-soluble binder When using a water-soluble binder as the negative electrode binder, it may further include a cellulose-based compound that can impart viscosity as a thickener.
  • a cellulose-based compound that can impart viscosity as a thickener.
  • carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, these alkali metal salts, etc. can be used in mixture of 1 or more types. Na, K or Li may be used as the alkali metal.
  • the amount of the thickener used may be 0.1 parts by weight to 3 parts by weight based on 100 parts by weight of the negative electrode active material.
  • the conductive material is used to impart conductivity to the electrode, and any battery can be used as long as it is an electron conductive material without causing chemical change in the battery.
  • the conductive material include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, denka black, and carbon fiber; Metal materials such as metal powder or metal fibers such as copper, nickel, aluminum and silver; Conductive polymers such as polyphenylene derivatives; Or a conductive material containing a mixture of these.
  • the current collector may be selected from the group consisting of copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof.
  • the cathode active material layer and the anode active material layer are formed by mixing an anode active material, a binder, and optionally a conductive material in a solvent to prepare an active material composition, and applying the active material composition to a current collector. Since the method of forming the active material layer is well known in the art, detailed description thereof will be omitted. N-methylpyrrolidone may be used as the solvent, but is not limited thereto. In addition, when a water-soluble binder is used for the negative electrode active material layer, water may be used as a solvent used when preparing the negative electrode active material composition.
  • a separator may exist between the positive electrode and the negative electrode according to the type of the lithium secondary battery.
  • the separator polyethylene, polypropylene, polyvinylidene fluoride or two or more multilayer films thereof may be used, and polyethylene / polypropylene two-layer separator, polyethylene / polypropylene / polyethylene three-layer separator, polypropylene / polyethylene / poly It goes without saying that a mixed multilayer film such as a propylene three-layer separator can be used.
  • FIG. 1 is an exploded perspective view of a rechargeable lithium battery according to one embodiment of the present invention.
  • a lithium secondary battery according to an embodiment is described as an example of being rectangular, the present invention is not limited thereto, and may be applied to various types of batteries, such as a cylindrical shape and a pouch type.
  • the lithium secondary battery 100 includes an electrode assembly 40 and an electrode assembly 40 interposed between the positive electrode 10 and the negative electrode 20 with a separator 30 interposed therebetween. It may include a case 50 is built.
  • the positive electrode 10, the negative electrode 20, and the separator 30 may be impregnated with an electrolyte (not shown).
  • Ethyl 3-chloropropionate (3-99-chloropropionate, 6.99 g, 51.2 mmol) was dissolved in diethyl ether (35 mL), and then titanium isopropoxide (titanium (IV) isopropoxide, 2.91 g, 10.2 mmol , 20 mol%) was added.
  • ethyl magnesium bromide (EtMgBr, 2.5 eq, magnesium: 3.12 g (128 mmol), ethyl bromide: 14.0 g, 12.8 mmol, diethyl ether: 94 mL) was slowly added dropwise at 0 ° C.
  • reaction product was stirred at room temperature for 1 hour. Subsequently, the reaction product was sufficiently acidic and 10% sulfuric acid aqueous solution (about 50 mL) was added to dissolve the solid, thereby completing the reaction.
  • the resulting aqueous solution was extracted three times with diethyl ether (100 mL) to obtain an organic layer.
  • the obtained organic layer was washed sequentially with water, saturated aqueous sodium hydrogen carbonate solution and saturated aqueous sodium chloride solution.
  • Anhydrous sodium sulfate was added to the washed product to remove residual water, filtered under reduced pressure, and all solvents were removed under vacuum.
  • 1 H NMR of the prepared 1- (2-chloroethyl) cyclopropan-1-ol was measured.
  • 1 H-NMR was measured using a Varian NMR system (Varian, Inc., 400 MHz, CDCl 3 ), and 13 C NMR was measured using the Varian NMR system (Varian, Inc., 100 MHz, CDCl 3 ). Measured using.
  • the resulting reaction mixture was stirred at room temperature for 2 hours. Subsequently, saturated ammonium chloride aqueous solution (about 30 mL) was added to the stirred product to terminate the reaction. The resulting aqueous solution was extracted three times with ethyl acetate (100 mL) to obtain an organic layer. The obtained organic layer was washed with saturated aqueous sodium chloride solution. Anhydrous sodium sulfate was added to the washed product to remove residual water, filtered under reduced pressure, and all solvents were removed under vacuum.
  • the 1 H NMR of the prepared 1- (2-chloroethyl) cyclopropyl methanesulfonate was measured.
  • 1 H-NMR was measured using a Varian NMR system (Varian, Inc., 400 MHz, CDCl 3 ), and 13 C NMR was measured using the Varian NMR system (Varian, Inc., 100 MHz, CDCl 3 ). Measured using.
  • the resulting reaction mixture was stirred for 10 hours at room temperature and all benzene was removed under vacuum. Subsequently, water (20 mL) was added to the obtained product until all solids dissolved, and the obtained aqueous solution was extracted three times with ethyl acetate (100 mL) to obtain an organic layer. The obtained organic layer was washed twice with water (20 mL) and then with saturated aqueous sodium chloride solution. Anhydrous sodium sulfate was added to the washed product, and the remaining water was removed. After filtration under reduced pressure, all solvents were removed under vacuum.
  • 1 H NMR of the prepared 4-oxa-5-thiaspiro [2.5] octane 5,5-dioxide was measured as follows. In the following experimental results, 1 H-NMR was measured using a Varian NMR system (Varian, Inc., 400 MHz, CDCl 3 ), and 13 C NMR was measured using the Varian NMR system (Varian, Inc., 100 MHz, CDCl 3 ). Measured using.
  • the cyclic current voltage (scan rate: 1 mV / sec) of the three electrodes using the additive solution, the graphite working electrode, and the lithium counter electrode was measured, and the results are shown in FIG. 2A.
  • an enlarged view of FIG. 2A is shown in FIG. 2B.
  • LiPF 6 1.5M LiPF 6 was dissolved in a mixed solvent of ethylene carbonate, ethylmethyl carbonate and dimethyl carbonate (2: 4: 4 volume ratio) to prepare a reference solution.
  • the cyclic current voltage (scan rate: 1 mV / sec) of the three electrodes using the reference solution, the graphite working electrode, and the lithium counter electrode was measured, and the results are shown in FIG. 3.
  • cycleX means cycle number of times.
  • the additive solution containing the additive prepared in Preparation Example 3 the reaction occurs at a high potential, it can be seen that the reactivity to the negative electrode increases.
  • the additive solution showed a decomposition peak, i.e., a reducing peak at 1.5 V, and since the reaction occurs at a higher potential than ethylene carbonate, which generally shows a reducing peak at 0.5 V, This result means that it is reduced before ethylene carbonate.
  • the solvent of the electrolyte does not show a special reduction peak.
  • LiPF 6 1.5M LiPF 6 was dissolved in a mixed solvent of ethylene carbonate, ethylmethyl carbonate and dimethyl carbonate (2: 4: 4 volume ratio) to prepare a reference solution.
  • anode polarization was measured using a linear scanning potential method, and the results are shown in FIG. 4.
  • a three-electrode electrochemical cell using Pt electrode as a working electrode and Li as a counter electrode and a reference electrode was used.
  • the scan was performed at 3V to 7V at a speed of 1mV / sec.
  • the additive solution containing the additive prepared in Preparation Example 3 has a larger oxidative decomposition current than the reference solution, which means that the oxidative decomposition is lower than the additive solution (oxidative decomposition starting point: 4.3 V) (4.2). Starting from V), it can also be seen from this result that the reactivity with respect to the positive electrode is excellent.
  • EC / PC / EP / PP 2 / 1/3/4 volume ratio
  • 7% by weight of fluoroethylene carbonate, 1% by weight of vinylene carbonate, 0.2% by weight of LiBF 4 , 2% by weight of succinonitrile and hexane tricyanide 2 wt% was added, and 1 wt% of the first additive represented by Chemical Formula 1-4B prepared in Preparation Example 3 was added to prepare an electrolyte for a lithium secondary battery.
  • An electrolyte for a lithium secondary battery was prepared in the same manner as in Example 1 except that the propanesultone second additive was further added.
  • the electrolyte for a lithium secondary battery of Example 2 is a mixed non-aqueous organic solvent of 1.15 M LiPF 6 lithium salt of ethylene carbonate (EC), propylene carbonate (PC), ethyl propionate (EP) and propyl propionate (PP).
  • EC ethylene carbonate
  • PC propylene carbonate
  • EP ethyl propionate
  • PP propyl propionate
  • An electrolyte for a lithium secondary battery was prepared in the same manner as in Example 1 except that the first additive represented by Chemical Formula 1-4B, which was prepared in Preparation Example 3, was not used.
  • the electrolyte of Comparative Example 1 is a mixed non-aqueous organic solvent (EC) of 1.15M LiPF 6 lithium salt of ethylene carbonate (EC), propylene carbonate (PC), ethyl propionate (EP) and propyl propionate (PP).
  • EC ethylene carbonate
  • PC propylene carbonate
  • EP ethyl propionate
  • PP propyl propionate
  • An electrolyte for a lithium secondary battery was prepared in the same manner as in Example 1 except that propanesultone was added instead of the first additive represented by Chemical Formula 1-4B prepared in Preparation Example 3.
  • the electrolyte of Comparative Example 1 is a mixed non-aqueous organic solvent (EC) of 1.15M LiPF 6 lithium salt of ethylene carbonate (EC), propylene carbonate (PC), ethyl propionate (EP) and propyl propionate (PP).
  • EC ethylene carbonate
  • PC propylene carbonate
  • EP ethyl propionate
  • PP propyl propionate
  • a cathode active material slurry was prepared by mixing 96% by weight of LiCoO 2 cathode active material, 2% by weight of Ketjen Black conductive material and 2% by weight of polyvinylidene fluoride in an N-methylpyrrolidone solvent.
  • the positive electrode active material slurry was coated on aluminum foil, dried, and rolled to prepare a positive electrode.
  • a lithium secondary battery was prepared in a conventional manner. At this time, the electrolyte injection amount was used 5.8g.
  • the thickness increase rate with respect to the initial thickness (%) was calculated and, among the results, the thickness increase rate (%) after 21 days is shown in Table 1 below, and the results after 7 days, 14 days, and 21 days are shown in FIG. 6.

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Abstract

La présente invention concerne un électrolyte pour une batterie secondaire au lithium, et une batterie secondaire au lithium le comprenant, l'électrolyte comprenant : un solvant organique non aqueux; un sel de lithium; et un premier additif représenté par une formule chimique spécifique.
PCT/KR2017/012092 2016-11-08 2017-10-30 Électrolyte pour batterie secondaire au lithium et batterie secondaire au lithium le comprenant WO2018088743A1 (fr)

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WO2024011616A1 (fr) * 2022-07-15 2024-01-18 宁德时代新能源科技股份有限公司 Batterie secondaire, module de batterie, bloc-batterie et dispositif électrique

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KR20130054127A (ko) * 2011-11-14 2013-05-24 삼성에스디아이 주식회사 리튬 이차 전지용 전해액 및 이를 포함하는 리튬 이차 전지
JP2014026885A (ja) * 2012-07-27 2014-02-06 Fujifilm Corp 非水二次電池用電解液及び二次電池
KR20150117176A (ko) * 2014-04-09 2015-10-19 삼성에스디아이 주식회사 리튬 이차 전지용 전해액 및 이를 포함하는 리튬 이차 전지
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023147332A1 (fr) * 2022-01-25 2023-08-03 Sila Nanotechnologies, Inc. Électrolytes pour éléments de batterie au lithium-ion avec des additifs nitrile
WO2024011616A1 (fr) * 2022-07-15 2024-01-18 宁德时代新能源科技股份有限公司 Batterie secondaire, module de batterie, bloc-batterie et dispositif électrique

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