WO2023098268A1 - 一种电解液、包含该电解液的电化学装置及电子装置 - Google Patents

一种电解液、包含该电解液的电化学装置及电子装置 Download PDF

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WO2023098268A1
WO2023098268A1 PCT/CN2022/122142 CN2022122142W WO2023098268A1 WO 2023098268 A1 WO2023098268 A1 WO 2023098268A1 CN 2022122142 W CN2022122142 W CN 2022122142W WO 2023098268 A1 WO2023098268 A1 WO 2023098268A1
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electrolyte
mass percentage
mass
electrolytic solution
positive electrode
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PCT/CN2022/122142
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English (en)
French (fr)
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刘建
崔辉
王亮
唐超
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宁德新能源科技有限公司
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Publication of WO2023098268A1 publication Critical patent/WO2023098268A1/zh

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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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0569—Liquid materials characterised by the solvents
    • 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
    • H01M2300/0028—Organic electrolyte characterised by the solvent
    • H01M2300/0037—Mixture of solvents
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the invention relates to the field of electrochemistry, in particular to an electrolytic solution, an electrochemical device and an electronic device containing the electrolytic solution.
  • Lithium-ion batteries can become the most popular and favored electrical energy storage devices today, mainly because of their advantages such as good environmental friendliness, high energy density, high working voltage and long cycle life.
  • the solvent is the main component of the electrolyte, and the stability of the solvent is crucial to the stability of the high-voltage electrolyte.
  • Traditional carbonate or carboxylate solvents are prone to oxidative decomposition when the charging cut-off voltage is higher than 4.3V.
  • the continuous oxidative decomposition of the electrolyte will increase the impedance of the battery interface on the one hand; on the other hand, the rapid consumption of the solvent will lead to a broken bridge in lithium ion transmission. In view of this, it is urgent to solve the stability of solvents under high voltage.
  • the purpose of the present application is to provide an electrolytic solution, an electrochemical device and an electronic device containing the electrolytic solution, so as to improve the cycle life of the high-voltage electrochemical device.
  • the specific technical scheme is as follows:
  • the first aspect of the present application provides a kind of electrolytic solution, and it comprises fluoroethylene carbonate, the fluorocarboxylate represented by general formula (I) and the fluoroether represented by general formula (II):
  • R 1 and R 2 are each independently selected from C 1 to C 5 alkyl, fluorine substituted C 1 to C 5 alkyl, sulfonic acid substituted C 2 to C 5 alkyl, cyano substituted C 2 to C 5 alkyl, and at least one of R 1 and R 2 is a fluorine-substituted C 1 to C 5 alkyl;
  • R 3 and R 4 are each independently selected from C 1 to C 5 alkyl, fluorine substituted C 1 to C 5 alkyl, sulfonic acid substituted C 2 to C 5 alkyl, cyano substituted C 2 to C 5 alkyl, and at least one of R 3 and R 4 is a fluorine-substituted C 1 to C 5 alkyl.
  • the inventors of the present application have found that because the fluorine atom has strong electronegativity and weak polarity, the fluorinated substance has a higher oxidation potential, and the electrolytic solution includes fluoroethylene carbonate, general formula ( The fluorocarboxylate represented by I) and the fluoroether represented by the general formula (II) produce a synergistic effect, which can effectively improve the oxidative window of the electrolyte, effectively reduce the oxidative decomposition of the solvent at the positive electrode interface, and the electrolyte of the present application When applied to a high-voltage electrochemical device, the cycle life of the high-voltage electrochemical device can be improved.
  • the fluorocarboxylate represented by the general formula (I) includes at least one of the following formulas (I-1) to (I-4):
  • the fluoroethers represented by the general formula (II) include at least one of the following formulas (II-1) to (II-4):
  • the electrolyte meets at least one of the following characteristics:
  • the mass percentage of the fluorocarboxylate is 10% to 20%, for example, the mass percentage of the fluorocarboxylate can be 10%, 12% , 14%, 16%, 18%, 20% or any range therebetween, without being limited to any theory, the applicant found that by controlling the mass percentage of fluorocarboxylate within the above range, the application's The electrolyte is applied to high-voltage electrochemical devices, which can further improve the cycle life of high-voltage electrochemical devices;
  • the mass percentage of the fluoroether is 5% to 15%, for example, the mass percentage of the fluoroether can be 5%, 7%, 9%, 11%, 13%, 15% or any range therebetween, not limited to any theory, the applicant found that by controlling the mass percentage of fluoroether within the above range, the overall impedance of the electrolyte is low, and the application The high-voltage electrolyte is applied to high-voltage electrochemical devices, which can further improve the cycle life of high-voltage electrochemical devices;
  • the mass percentage of the fluoroether and the mass percentage of the fluorocarboxylate meet: the mass percentage of the fluoroether/the The mass percentage of fluorocarboxylate ⁇ 2/3, for example, can be 0, 1/6, 1/3, 2/3 or any range in between, when the fluoroether and fluorocarboxylate When the ratio is >2/3, due to the high viscosity of the fluoroether, the overall viscosity of the electrolyte increases, and the overall impedance of the electrolyte increases, which affects the transmission of lithium ions inside the electrolyte, which is not conducive to the overall performance of the high-voltage electrochemical device. sex;
  • the ratio of the mass percentage of the fluoroethylene carbonate (FEC) to the sum of the mass percentages of the fluoroether and the fluorocarboxylate X 0.1 ⁇ X ⁇ 0.6, for example, X can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6 or any range in between, when the relative content of FEC is high (X is greater than 0.6), due to the characteristics of FEC itself , causing the battery to deteriorate significantly during high-temperature storage; when the relative content of FEC is low (X is less than 0.1), it will lead to stratification of fluorinated substances and carbonates, and uneven mixing of substances, which will lead to interface deterioration during cycling on the one hand; On the other hand, it affects the transport of lithium ions in the electrolyte.
  • FEC fluoroethylene carbonate
  • the applicant found that by synergistically controlling the mass percentages of fluorocarboxylate, fluoroether and FEC to meet one, two or more combinations of the above conditions, the present application can When the electrolyte solution is applied to a high-voltage electrochemical device, the cycle life of the high-voltage electrochemical device is further improved.
  • the electrolyte meets at least one of the following characteristics:
  • the electrolyte also includes non-fluorinated carboxylate and cyclic carbonate, based on the total mass of the electrolyte, the sum of the mass percentages of the fluoroether and the fluorinated carboxylate
  • the mass percentage ratio to the non-fluorinated carboxylate is Z, and Z satisfies: 0.8 ⁇ Z ⁇ 2, for example, Z can be 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0 or any range therebetween, when the mass percentage of non-fluorinated carboxylate is higher (Z is less than 0.8), the electrolyte stability becomes poor; when the mass percentage of non-fluorinated carboxylate When the component content is low (Z is greater than 2), the increase in the mass percentage of fluorinated substances will increase the overall viscosity of the electrolyte, and at the same time affect the dissociation of lithium salts, resulting in the deterioration of the performance of
  • the electrolyte also includes a non-fluorinated carboxylate and a cyclic carbonate, based on the total mass of the electrolyte, the mass percentage of the non-fluorinated carboxylate and the cyclic carbonate
  • the ratio of mass percent content is Y, 0.5 ⁇ Y ⁇ 1, for example, Y can be 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1 or any range therebetween.
  • the electrolyte has better kinetic properties and viscosity, and the application of the electrolyte of the present application to a high-voltage electrochemical device can improve the cycle life of the high-voltage electrochemical device.
  • the electrolyte solution of the present application can be applied to high-voltage electrochemical devices by synergistically controlling non-fluorinated carboxylic acid esters and cyclic carbonates to meet one or both of the above conditions , further improving the cycle life of high-voltage electrochemical devices.
  • the present application has no particular limitation on the cyclic carbonate, as long as the purpose of the application can be achieved, for example, the cyclic carbonate may include but not limited to ethylene carbonate, propylene carbonate, trimethylene cyclocarbonate, 2, At least one of 2-dimethyltrimethylene cyclocarbonate.
  • non-fluorinated carboxylate may include but not limited to methyl formate, ethyl formate, methyl propionate, propionate, at least one of ethyl propionate, propyl propionate, ⁇ -butyrolactone, decanolactone, valerolactone or caprolactone.
  • the electrolyte also contains a sultone represented by general formula (III), based on the total mass of the electrolyte, the mass percentage of the sultone is the same as the The mass percentage ratio of the fluorocarboxylate is K, 0.18 ⁇ K ⁇ 0.9, for example, K can be 0.18, 0.25, 0.35, 0.45, 0.55, 0.65, 0.75, 0.85, 0.90 or any range therebetween:
  • R 5 can be selected from single bond, C 1 to C 3 alkylene
  • R 6 , R 7 and R 8 are each independently selected from H, halogen, and C 2 -C 5 hydrocarbon groups containing unsaturated bonds.
  • the sultone represented by the general formula (III) comprises at least one of the following formulas (III-1) to (III-6):
  • the electrolyte includes vinylene carbonate represented by general formula (IV), based on the total mass of the electrolyte, the mass percentage of the vinylene carbonate and the fluorine
  • the mass percentage ratio of carboxylic acid ester is M, 0.008 ⁇ M ⁇ 0.2, for example, M can be 0.008, 0.02, 0.04, 0.06, 0.08, 0.1, 0.12, 0.14, 0.16, 0.18, 0.2 or any in between scope:
  • R 9 and R 10 are each independently selected from H, halogen, and C 2 -C 5 hydrocarbon groups containing unsaturated bonds.
  • vinylene carbonate mass percentage content is less (M is less than 0.008), can't effectively suppress the reaction of fluorocarboxylate at negative electrode interface;
  • vinylene carbonate mass percentage content is more (M is greater than 0.2), increase Negative electrode interfacial impedance is lowered, lithium ion transmission process deteriorates, so the ratio of mass percent content of vinylene carbonate and fluorocarboxylate is controlled within the above range, and the electrolyte of the present application is applied to high-voltage electrochemistry
  • the device can further improve the cycle life of the high-voltage electrochemical device.
  • the vinylene carbonate represented by the general formula (IV) comprises at least one of the following formulas (IV-1) to (IV-4):
  • the electrolyte further comprises a nitrile compound represented by general formula (V), based on the total mass of the electrolyte, the mass percentage of the nitrile compound is equal to the fluorinated
  • the mass percentage ratio of carboxylate is L, 0.02 ⁇ L ⁇ 0.8, for example, L can be 0.02, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or any range therebetween:
  • n is an integer selected from 1-3;
  • R 11 , R 12 , R 13 , and R 14 are each independently selected from H, substituted or unsubstituted C 1 to C 10 alkyl, substituted or unsubstituted groups represented by formula (VA), substituted or The group shown in unsubstituted formula (VB), the group shown in substituted or unsubstituted formula (VC), the group shown in substituted or unsubstituted formula (VD), substituted or unsubstituted Substituted groups represented by formula (VE), substituted or unsubstituted C 2 -C 10 alkoxycarbonyl groups, when substituted, each substituent is independently selected from halogen:
  • a, b, c, d, e, f, g, h, i, j, k are each independently selected from an integer of 0-10;
  • At least two of R 11 , R 12 , R 13 , and R 14 are selected from groups containing cyano.
  • the mass percentage content of nitrile compound is low (L is less than 0.02), the positive electrode interface is protected insufficiently, causes electrolyte to consume unevenly at the positive electrode interface, and the cycle performance of electrochemical device is improved not obviously;
  • the quality of nitrile compound When the percentage content is higher (L is greater than 0.8), the impedance of the positive electrode interface increases, hindering the lithium ion transmission process, so the above-mentioned nitrile compounds are selected to control the ratio of the mass percentage content of the nitrile compound and the mass percentage content of the fluorocarboxylate.
  • the ratio is within the above range, when the electrolyte solution of the present application is applied to a high-voltage electrochemical device, the cycle life of the high-voltage electrochemical device can be improved.
  • the nitrile compound represented by the general formula (V) comprises at least one of the following formulas (V-1) to (V-10):
  • the applicant found that by selecting the above-mentioned nitrile compounds, when the electrolyte solution of the present application is applied to a high-voltage electrochemical device, the cycle life of the high-voltage electrochemical device can be further improved.
  • the electrolyte also includes lithium difluorooxalate borate (LiBOB), based on the total mass of the electrolyte, the mass percentage of the lithium difluorooxalate borate is the same as that of the fluorinated lithium oxalate
  • the mass percentage ratio of carboxylate is H, and H satisfies: 0.004 ⁇ H ⁇ 0.2, for example, H can be 0.004, 0.008, 0.025, 0.045, 0.065, 0.085, 0.105, 0.125, 0.145, 0.165, 0.185, 0.2 or for any range in between.
  • the mass percentage of lithium difluorooxalate borate in the electrolyte is too low (H is less than 0.004), a stable protective film cannot be formed at the interface between the positive and negative electrodes, and no effective protective effect can be achieved; when the lithium difluorooxalate borate When the mass percentage content is too high (H is greater than 0.2), it will cause the deterioration of the safety performance of the electrochemical device, so the ratio of the mass percentage content of lithium difluorooxalate borate to the mass percentage content of fluorocarboxylate is controlled within the above range, When the electrolyte solution of the present application is applied to a high-voltage electrochemical device, the cycle life of the high-voltage electrochemical device can be further improved.
  • the electrolyte comprises vinyl sulfate represented by general formula (VI) or general formula (VII), based on the total mass of the electrolyte, the mass percentage of vinyl sulfate
  • the mass percentage ratio of the fluorocarboxylate is N, 0.012 ⁇ N ⁇ 0.2, for example, N can be 0.012, 0.02, 0.04, 0.06, 0.08, 0.1, 0.12, 0.14, 0.16, 0.18, 0.2 or for any range in between:
  • W selected from m is an integer from 1 to 4, n is an integer from 0 to 2, and p is an integer from 0 to 6;
  • M is selected from a single bond or methylene
  • R 15 and R 16 are each independently selected from H, C 1 to C 6 alkyl groups, groups shown in formula (VII-A) or groups shown in formula (VII-B):
  • R 17 is selected from halogen, C 1 to C 6 haloalkyl, C 1 to C 6 alkoxy.
  • N is less than 0.012
  • SEI solid electrolyte
  • the vinyl sulfate represented by the general formula (VI) or the general formula (VII) includes the following formulas (VI-1) to (VI-4), (VII-1) to (VII -at least one of 4):
  • the electrolyte solution also includes a lithium salt.
  • the present application has no particular limitation on the lithium salt, as long as the purpose of the present application can be achieved.
  • the lithium salt may include but not limited to lithium hexafluorophosphate, lithium tetrafluoroborate, At least one of lithium hexafluoroarsenate, lithium perchlorate, lithium bisfluorosulfonyl imide, and lithium bistrifluoromethanesulfonyl imide, based on the total mass of the electrolyte, the mass of the lithium salt is 100%
  • the component content is 10% to 20%, such as 10%, 12%, 14%, 16%, 18%, 20%, or any range therebetween.
  • the second aspect of the present application provides an electrochemical device, including a positive electrode, a negative electrode and the electrolyte solution provided in the first aspect of the present application.
  • the electrolyte solution provided by the application has good stability under high pressure, so the electrochemical device provided by the application has a long service life and good cycle performance.
  • the electrochemical device satisfies at least one of the following characteristics:
  • the positive electrode includes a positive electrode active material, and the positive electrode active material contains aluminum element.
  • the mass percentage of the aluminum element is A%, and the value range of A is 0.01 to 1, such as can be 0.01, 0.05, 0.15, 0.25, 0.35, 0.45, 0.55, 0.65, 0.75, 0.85, 0.95, 1 or any range therebetween, the applicant found that the quality of the aluminum element on the surface of the positive electrode active material When the percentage content is too high (A is greater than 1), the positive electrode intercalation lithium ion resistance increases significantly, and the kinetic performance of the positive electrode active material deteriorates; when the mass percentage content of the aluminum element on the surface of the positive electrode active material is too low (A is less than 0.01), The optimization of the positive electrode active material is not obvious, resulting in no significant improvement in the cycle process of the electrochemical device.
  • the mass percentage of the aluminum element within the above range, it is more conducive to the improvement of the cycle performance of the high-voltage electrochemical
  • the positive electrode includes a positive electrode active material, and the positive electrode active material further includes lanthanum, zirconium, niobium or titanium element, based on the total mass of the positive electrode active material, the mass of the lanthanum, zirconium, niobium or titanium element is 100%
  • the content is B%, and the value range of B is 0.01 to 0.8. 0.75, 0.8 or any range therebetween, not limited to any theory, the applicant found that controlling the mass percentage of lanthanum, zirconium, niobium or titanium in the positive electrode active material within the above range is beneficial to improve the dynamics of the positive electrode interface Chemical properties, thereby further improving the cycle performance of high-voltage electrochemical devices;
  • the positive electrode includes a positive electrode active material, the positive electrode active material contains lanthanum, zirconium, niobium or titanium element, based on the total mass of the positive electrode active material, the mass of the lanthanum, zirconium, niobium or titanium element is 100%
  • the content is B%, and B/A satisfies: 0.01 ⁇ B/A ⁇ 0.8, such as 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8 or any range therebetween, without being limited to any theory, the applicant found that making the content of lanthanum, zirconium, niobium or titanium element and aluminum element satisfy the above relational formula is more conducive to improving the dynamics of the positive electrode interface Performance, can effectively form a stable protective layer on the surface of the positive electrode, reduce side reactions at the positive electrode interface, thereby improving the cycle performance of high-voltage electrochemical devices
  • the Dv50 of the negative electrode active material particle of the negative electrode is 8 ⁇ m to 20 ⁇ m, for example, Dv50 can be 8 ⁇ m, 12 ⁇ m, 14 ⁇ m, 16 ⁇ m, 18 ⁇ m, 20 ⁇ m or any range therebetween, not limited to any theory, the applicant found that, When the particle size of the negative electrode active material is within the above range, the negative electrode active material has good kinetic properties and will not affect the compacted density of the negative electrode, which is more conducive to the improvement of the cycle performance of the high-voltage electrochemical device.
  • the present application finds that the cycle performance of the high-voltage electrochemical device can be improved by synergistically controlling the electrochemical device to meet one, two or a combination of more than two of the above conditions.
  • the doping method of aluminum and lanthanum, zirconium, niobium or titanium in the positive electrode active material there is no special requirement for the doping method of aluminum and lanthanum, zirconium, niobium or titanium in the positive electrode active material, and can be mixed with lithium cobaltate, lithium At least one of the nickel-manganese-cobalt ternary material, lithium iron phosphate, and lithium nickel manganese oxide is mixed according to the target element ratio, and then sintered to obtain the corresponding positive electrode active material.
  • the positive electrode sheet usually includes a positive current collector.
  • the positive current collector is not particularly limited, as long as the purpose of this application can be achieved, for example, it may include but not limited to aluminum foil, aluminum alloy foil, or a composite current collector.
  • the thickness of the positive electrode collector there is no particular limitation on the thickness of the positive electrode collector, as long as the purpose of the present application can be achieved, for example, the thickness is 8 ⁇ m to 12 ⁇ m.
  • the positive electrode material layer may be provided on one surface in the thickness direction of the positive electrode current collector, or on two surfaces in the thickness direction of the positive electrode current collector. It should be noted that the "surface” here may be the entire area of the positive electrode collector, or a partial area of the positive electrode collector. This application is not particularly limited, as long as the purpose of this application can be achieved.
  • the positive electrode material layer includes the positive electrode active material in any of the foregoing embodiments of the present application, and the positive electrode material layer may also include a binder.
  • This application has no special restrictions on the binder, as long as the purpose of the application can be achieved
  • a conductive agent may also be included in the positive electrode material layer, and the present application has no special limitation on the conductive agent, as long as the purpose of the application can be realized, for example, it may include but not limited to conductive carbon black (Super P), carbon nanotubes (CNTs), carbon fiber, flake graphite, Ketjen black, graphene, metal material or conductive polymer.
  • the aforementioned carbon nanotubes may include, but are not limited to, single-walled carbon nanotubes and/or multi-walled carbon nanotubes.
  • the aforementioned carbon fibers may include, but are not limited to, vapor grown carbon fibers (VGCF) and/or carbon nanofibers.
  • the above metal material may include but not limited to metal powder and/or metal fiber, specifically, the metal may include but not limited to at least one of copper, nickel, aluminum or silver.
  • the aforementioned conductive polymer may include but not limited to at least one of polyphenylene derivatives, polyaniline, polythiophene, polyacetylene or polypyrrole.
  • the positive electrode may further include a conductive layer located between the positive electrode current collector and the positive electrode material layer.
  • the present application has no particular limitation on the composition of the conductive layer, which may be a commonly used conductive layer in the field, for example, may include but not limited to the above-mentioned conductive agent and the above-mentioned binder.
  • the negative electrode sheet in the present application is not particularly limited, as long as the purpose of the application can be achieved, for example, the negative electrode sheet generally includes a negative electrode current collector and a negative electrode material layer.
  • the negative electrode material layer may be provided on one surface in the thickness direction of the negative electrode current collector, or on two surfaces in the thickness direction of the negative electrode current collector. It should be noted that the "surface” here may be the entire area of the negative electrode collector, or a partial area of the negative electrode collector. This application is not particularly limited, as long as the purpose of this application can be achieved.
  • the negative electrode current collector is not particularly limited, as long as the purpose of this application can be achieved, for example, it may include but not limited to copper foil, copper alloy foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam or composite Collectors, etc.
  • the thickness of the current collector of the negative electrode is 4 ⁇ m to 12 ⁇ m.
  • the negative electrode material layer includes negative electrode active materials, wherein the negative electrode active material is not particularly limited, as long as the purpose of the application can be achieved, for example, it can include but not limited to natural graphite, artificial graphite, mesophase micro carbon spheres, hard Carbon, soft carbon, silicon, silicon-carbon composite, Li-Sn alloy, Li-Sn-O alloy, Sn, SnO, SnO 2 , lithiated TiO 2 -Li 4 Ti 5 O 12 or Li with spinel structure - at least one of Al alloys.
  • the negative electrode active material is not particularly limited, as long as the purpose of the application can be achieved, for example, it can include but not limited to natural graphite, artificial graphite, mesophase micro carbon spheres, hard Carbon, soft carbon, silicon, silicon-carbon composite, Li-Sn alloy, Li-Sn-O alloy, Sn, SnO, SnO 2 , lithiated TiO 2 -Li 4 Ti 5 O 12 or Li with spinel structure
  • the negative electrode material layer may also include a conductive agent.
  • the present application has no special limitation on the conductive agent, as long as the purpose of the present application can be achieved, for example, it may include but not limited to at least one of the above-mentioned conductive agents.
  • the negative electrode material layer may also include a binder, and the present application has no special restrictions on the binder, as long as the purpose of the application can be achieved, for example, it may include but not limited to at least one of the above-mentioned binders .
  • the negative electrode may further include a conductive layer located between the negative electrode current collector and the negative electrode material layer.
  • the present application has no particular limitation on the composition of the conductive layer, which may be a commonly used conductive layer in the field, and the conductive layer may include but not limited to the above-mentioned conductive agent and the above-mentioned binder.
  • This application has no special restrictions on the separator, as long as the purpose of this application can be achieved, for example, it can include but not limited to polyethylene (PE), polypropylene (PP), polytetrafluoroethylene-based polyolefin (PO) separators , polyester film (such as polyethylene terephthalate (PET) film), cellulose film, polyimide film (PI), polyamide film (PA), spandex, aramid film, woven film, non At least one of woven film (non-woven fabric), microporous film, composite film, separator paper, laminated film or spun film, preferably PP.
  • PET polyethylene terephthalate
  • PI polyimide film
  • PA polyamide film
  • aramid film woven film
  • woven film non At least one of woven film (non-woven fabric), microporous film, composite film, separator paper, laminated film or spun film, preferably PP.
  • the separator of the present application may have a porous structure, and the pore size is not particularly limited as long as the purpose of the present application can be achieved, for example, the pore size may be 0.01 ⁇ m to 1 ⁇ m.
  • the thickness of the isolation film is not particularly limited, as long as the purpose of the present application can be achieved, for example, the thickness may be 5 ⁇ m to 500 ⁇ m.
  • a separator may include a substrate layer and a surface treatment layer.
  • the substrate layer can be a non-woven fabric, film or composite film with a porous structure, and the material of the substrate layer can include but not limited to polyethylene, polypropylene, polyethylene terephthalate or polyimide at least one.
  • a polypropylene porous film, a polyethylene porous film, a polypropylene non-woven fabric, a polyethylene non-woven fabric, or a polypropylene-polyethylene-polypropylene porous composite film may be used.
  • at least one surface of the substrate layer is provided with a surface treatment layer, and the surface treatment layer may be a polymer layer or an inorganic layer, or a layer formed by mixing a polymer and an inorganic material.
  • the inorganic material layer may include but not limited to inorganic particles and inorganic material layer binder, and the present application has no special limitation on inorganic particles, for example, may include but not limited to aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, At least one of tin oxide, cerium oxide, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide or barium sulfate.
  • the present application has no particular limitation on the inorganic layer binder, for example, it may include but not limited to polyvinylidene fluoride, copolymer of vinylidene fluoride-hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, At least one of polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polymethylmethacrylate, polytetrafluoroethylene or polyhexafluoropropylene.
  • polyvinylidene fluoride copolymer of vinylidene fluoride-hexafluoropropylene
  • polyamide polyacrylonitrile
  • polyacrylate polyacrylic acid
  • the polymer layer contains a polymer, and the polymer material may include but not limited to polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylate, polyvinyl pyrrolidone, polyvinyl ether, polyvinylidene fluoride At least one of ethylene or poly(vinylidene fluoride-hexafluoropropylene).
  • the electrochemical device of the present application is not particularly limited, and it may include any device that undergoes an electrochemical reaction.
  • the electrochemical device may include, but is not limited to, a lithium metal secondary battery, a lithium ion secondary battery (lithium ion battery), a lithium polymer secondary battery, or a lithium ion polymer secondary battery, among others.
  • the preparation process of electrochemical devices is well known to those skilled in the art, and the present application is not particularly limited.
  • it may include but not limited to the following steps: stack the positive electrode sheet, separator and negative electrode sheet in sequence, and as required Winding, folding, etc. to obtain an electrode assembly with a winding structure, put the electrode assembly into a packaging bag, inject electrolyte into the packaging bag and seal it to obtain an electrochemical device; or, put the positive electrode, separator and negative electrode in order Stacking, and then fixing the four corners of the entire laminated structure with adhesive tape to obtain the electrode assembly of the laminated structure, putting the electrode assembly into a packaging bag, injecting electrolyte into the packaging bag and sealing it to obtain an electrochemical device.
  • overcurrent prevention elements, guide plates, etc. can also be placed in the packaging bag as needed, so as to prevent pressure rise and overcharge and discharge inside the electrochemical device.
  • the third aspect of the present application provides an electronic device, including the electrochemical device provided in the second aspect of the present application.
  • the electrochemical device provided by the application has good cycle performance, so the electronic device provided by the application has a long service life and good performance.
  • the electronic device of the present application is not particularly limited, and it may be used in any electronic device known in the prior art.
  • electronic devices may include, but are not limited to, notebook computers, pen-based computers, mobile computers, e-book players, cellular phones, portable fax machines, portable copiers, portable printers, headsets, VCRs, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, cars, motorcycles, power-assisted bicycles, bicycles, Lighting appliances, toys, game consoles, clocks, electric tools, flashlights, cameras, large household storage batteries and lithium-ion capacitors, etc.
  • the application provides an electrolytic solution, an electrochemical device and an electronic device containing the electrolytic solution.
  • a fluorinated substance By introducing a fluorinated substance into the electrolytic solution and utilizing the strong electronegativity and weak polarity of the fluorine atom, the fluorinated substance has A higher oxidation potential can effectively increase the oxidative window of the electrolyte, effectively reduce the oxidative decomposition of the solvent at the positive electrode interface, and reduce the solvent consumption of the electrolyte during the cycle, thereby improving the cycle life of the high-voltage electrochemical device. Therefore, it has broad application prospects for the development of high energy density electrical energy storage devices.
  • a lithium-ion battery is used as an example of an electrochemical device to explain the present application, but the electrochemical device of the present application is not limited to the lithium-ion battery.
  • Thickness expansion rate [(thickness after storage ⁇ thickness before storage)/thickness before storage] ⁇ 100%.
  • the lithium-ion battery At 45°C, charge the lithium-ion battery with a constant current of 1.3C to 4.2V, then charge it with a constant current of 0.5C to 4.55V, and finally charge it with a constant current of 0.05C, and then discharge it with a constant current of 0.5C to 3.0 V, this is the first cycle.
  • the lithium-ion battery was subjected to multiple cycles under the above conditions. Taking the capacity of the first discharge as 100%, the charge-discharge cycle was repeated, and when the discharge capacity retention rate decayed to 80%, the test was stopped and the number of cycles was recorded as an index for evaluating the cycle performance of lithium-ion batteries.
  • Dv50 is the cumulative diameter of 50% in the volume reference distribution of particles measured by laser scattering particle size analyzer.
  • the element content of the surface area of the sample was tested by the following method: the filtrate was fixed to 200ml, and the content of aluminum element and lanthanum element in the filtrate was tested by an inductively coupled plasma optical emission spectrometer (ICP-OES).
  • ICP-OES inductively coupled plasma optical emission spectrometer
  • the element content of the sample was tested by the following method: the filter residue was added to 10ml of aqua regia for complete digestion, the digested solution was adjusted to 50ml, and the content of lanthanum in the digestion solution was tested by ICP-OES.
  • Polyethylene (PE) porous polymer film is used as the isolation membrane.
  • fluorocarboxylate, fluoroether and FEC will affect the high temperature cycle performance and High temperature storage performance.
  • a high-voltage lithium-ion battery containing three substances of fluorocarboxylate, fluoroether and FEC is selected, and the above-mentioned substances are all within the scope of claim 1 of the present application, which can have good high-temperature cycle and high-temperature storage performance.
  • the ratio of the mass percentage of fluorocarboxylate and the mass percentage of fluoroether usually also affects the high-temperature cycle performance and high-temperature storage performance of high-voltage lithium-ion batteries, which can be obtained from Example 1-1 to Example 1-7 It can be seen that the high-voltage lithium-ion battery whose mass percentage of fluorocarboxylate and fluoroether is within the scope of the present application can have better high-temperature cycle performance and high-temperature storage performance.
  • the ratio Z of the sum of fluorinated carboxylate and fluoroether mass percentage content to the non-fluorinated carboxylate mass percentage content usually also affects the high-temperature cycle performance and high-temperature storage performance of high-voltage lithium-ion batteries, from the embodiment From 1-1 to Examples 1-7, it can be seen that choosing a high-voltage lithium-ion battery with a value of Z within the scope of this application can have better high-temperature cycle performance and high-temperature storage performance.
  • the ratio X of the mass percent content of FEC to the sum of the mass percent content of fluorocarboxylate and fluoroether usually also affects the high-temperature cycle performance and high-temperature storage performance of high-voltage lithium-ion batteries, from Example 1-1 to Example 1-3 and Examples 1-5 to 1-7, it can be seen that choosing a high-voltage lithium-ion battery with a value of X within the scope of this application can have better high-temperature cycle performance and high-temperature storage performance.
  • Example 1-2 Except for adjusting the type and mass percentage of sultone according to Table 2, the rest is the same as that of Example 1-2.
  • Example 2-1 to Example 2-13 it can be seen that sultones generally also affect the high-temperature cycle performance and high-temperature storage performance of high-voltage lithium-ion batteries.
  • Example 2-4 to Example 2-6 As can be seen from Example 2-8 to Example 2-10 and Example 2-12 to Example 2-13, the sultone containing general formula (III) is selected for use, and the sultone mass percentage content
  • a high-voltage lithium-ion battery whose ratio K to the mass percent content of the fluorocarboxylate falls within the scope of the present application can have better high-temperature cycle performance and high-temperature storage performance.
  • Example 3-1 to Example 3-11 that the vinylene carbonate represented by the general formula (IV) generally also affects the high-temperature cycle performance of the high-voltage lithium-ion battery.
  • embodiment 3-2 to embodiment 3-5 and embodiment 3-7 to embodiment 3-11 select for use to comprise the vinylene carbonate represented by general formula (IV), and vinylene carbonate mass percentage
  • a high-voltage lithium-ion battery whose ratio M of the content to the mass percent content of the fluorocarboxylate falls within the scope of the application can have better high-temperature cycle performance.
  • Example 1-2 Except for adjusting the type and mass percentage of nitrile compounds according to Table 4, the rest are the same as in Example 1-2.
  • Example 4-1 to Example 4-18 that the nitrile compound represented by the general formula (V) generally also affects the high-temperature cycle performance and high-temperature storage performance of the high-voltage lithium-ion battery.
  • select for use comprise the nitrile compound represented by general formula (V), and the ratio L of nitrile compound mass percentage content and fluorocarboxylate mass percentage content
  • the high-voltage lithium-ion battery within the scope of the present application can have better high-temperature cycle performance and high-temperature storage performance.
  • LiBOB in the electrolyte usually also affects the high-temperature cycle performance of the high-voltage lithium-ion battery.
  • LiBOB is selected for use, and the ratio H of LiBOB mass percentage content to fluorocarboxylate mass percentage content is within the scope of this application. , can have good high temperature cycle performance.
  • Example 6-1 to Example 6-14 that the vinyl sulfate represented by the general formula (VI) and the general formula (VII) generally also affects the high-temperature cycle performance and high-temperature storage performance of the high-voltage lithium-ion battery.
  • embodiment 6-2 to embodiment 6-14 select the vinyl sulfate that comprises general formula (VI) and general formula (VII) for use, and vinyl sulfate mass percentage content and fluorocarboxylate quality
  • a high-voltage lithium-ion battery with a percentage ratio N within the scope of the present application can have good high-temperature cycle performance and high-temperature storage performance.
  • Example 7-1 to Example 7-29 that on the basis of using fluorocarboxylate, fluoroether and FEC, adding sultone, vinylene carbonate, nitrile At least two of these compounds, LiBOB, and vinyl sulfate have a good synergistic effect, and can more effectively improve the high-temperature cycle and high-temperature storage performance of the high-voltage lithium-ion battery.

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Abstract

本申请提供了一种电解液、包含该电解液的电化学装置及电子装置，其中，电解液包括氟代碳酸乙烯酯、通式(I)表示的氟代羧酸酯和通式(II)表示的氟代醚，上述三种物质具有协同效果，可以有效提高电解液的氧化性窗口，降低溶剂在正极界面的氧化分解，减少电解液在循环过程中的溶剂消耗，从而改善高压电化学装置的循环寿命。

Description

一种电解液、包含该电解液的电化学装置及电子装置
本申请要求于2021年12月3日提交中国专利局、申请号为202111470365.7发明名称为“一种电解液、包含该电解液的电化学装置及电子装置”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明涉及电化学领域，具体是涉及一种电解液、包含该电解液的电化学装置及电子装置。
背景技术
锂离子电池能够成为现如今最流行和青睐的电能储能器件，主要是因为具有好的环境友好性、高的能量密度、高的工作电压和长的循环寿命等优点。
但随着人类生活水平的提高，对于电能储能器件的要求越来越高，特别是对于锂离子电池能量密度的需求。提高锂离子电池的工作电压是提高锂离子电池能量密度的重要手段之一，但传统的电解液已经无法满足现如今的工作要求，因此发展高电压电解液迫在眉睫。
溶剂作为电解液的主要成分，溶剂的稳定性对于高压电解液稳定性至关重要。传统的碳酸酯类或羧酸酯类溶剂当充电截至电压高于4.3V时很容易发生氧化分解。电解液持续氧化分解，一方面会增加电池界面的阻抗；另一方面溶剂快速消耗导致锂离子传输出现断桥。有鉴于此，亟需解决溶剂在高电压下的稳定性问题。
发明内容
本申请的目的在于提供一种电解液、包含该电解液的电化学装置及电子装置，以改善高压电化学装置的循环寿命。具体技术方案如下：
本申请的第一方面提供了一种电解液，其包括氟代碳酸乙烯酯、通式(I)表示的氟代羧酸酯和通式(II)表示的氟代醚：
Figure PCTCN2022122142-appb-000001
其中，
R 1和R 2各自独立地选自C 1至C 5的烷基、氟取代的C 1至C 5的烷基、磺酸基取代的C 2至C 5的烷基、氰基取代的C 2至C 5的烷基，且R 1和R 2中至少一个为氟取代的C 1至C 5的烷基；
R 3和R 4各自独立地选自C 1至C 5的烷基、氟取代的C 1至C 5的烷基、磺酸基取代的C 2至C 5的烷基、氰基取代的C 2至C 5的烷基，且R 3和R 4中至少一个为氟取代的C 1至C 5的烷基。
通过深入研究，本申请的发明人发现，由于氟原子具有很强的电负性和弱极性，被氟化的物质具有较高的氧化电位，电解液包括氟代碳酸乙烯酯、通式(I)表示的氟代羧酸酯和通式(II)表示的氟代醚产生协同效果，可以有效提高电解液的氧化性窗口，有效降低溶剂在正极界面的氧化分解，将本申请的电解液应用于高压电化学装置，可以改善高压电化学装置的循环寿命。
本申请的一种实施方案中，所述通式(I)表示的氟代羧酸酯包括下式(I-1)至(I-4)中的至少一种：
Figure PCTCN2022122142-appb-000002
所述通式(II)表示的氟代醚包括下式(II-1)至(II-4)中的至少一种：
Figure PCTCN2022122142-appb-000003
不限于任何理论，本申请人发现，选择上述氟代羧酸酯和氟代醚时，将本申请的电解液应用于高压电化学装置，可以进一步改善高压电化学装置的循环寿命。
本申请的一种实施方案中，所述电解液满足如下特征中的至少一种：
(1)基于所述电解液的总质量，所述氟代羧酸酯的质量百分含量为10％至20％，例如，氟代羧酸酯的质量百分含量可以为10％、12％、14％、16％、18％、20％或为其间的任何范围，不限于任何理论，本申请人发现，通过控制氟代羧酸酯的质量百分含量在上述范围内，将本申请的电解液应用于高压电化学装置，能够进一步改善高压电化学装置的循环寿命；
(2)基于所述电解液的总质量，所述氟代醚的质量百分含量为5％至15％，例如，氟代醚的质量百分含量可以为5％、7％、9％、11％、13％、15％或为其间的任何范围，不限于任何理论，本申请人发现，通过控制氟代醚的质量百分含量在上述范围内，电解液整体阻抗较低，将本申请的电解液应用于高压电化学装置，可以进一步改善高压电化学装置的循环寿命；
(3)基于所述电解液的总质量，所述氟代醚的质量百分含量与所述氟代羧酸酯的质量百分含量满足：所述氟代醚的质量百分含量/所述氟代羧酸酯的质量百分含量≤2/3，例如，可以为0、1/6、1/3、2/3或为其间的任何范围，当氟代醚与氟代羧酸酯的比例>2/3时，由于氟代醚的粘度较大，使电解液整体的粘度增大，电解液阻抗整体上升，影响锂离子在电解液内部的传输，不利于高压电化学装置的整体性；
(4)基于所述电解液的总质量，所述氟代碳酸乙烯酯(FEC)的质量百分含量与所述 氟代醚和所述氟代羧酸酯的质量百分含量之和的比值为X，0.1≤X≤0.6，例如，X可以为0.1、0.2、0.3、0.4、0.5、0.6或为其间的任何范围，当FEC相对含量较高时(X大于0.6)，由于FEC自身的特性，导致电池在高温存储过程中明显恶化；当FEC相对含量较低(X小于0.1)时，会导致氟代物质与碳酸酯发生分层，物质混合不均匀，一方面导致循环过程中界面恶化；另一方面影响锂离子在电解液中的传输。
不限于任何理论，本申请人发现，通过协同控制氟代羧酸酯、氟代醚和FEC的质量百分含量满足上述条件中的一种、两种或两种以上的组合，可以使本申请的电解液应用于高压电化学装置时，进一步改善高压电化学装置的循环寿命。
本申请的一种实施方案中，所述电解液满足如下特征中的至少一种：
(1)所述电解液还包含非氟代羧酸酯和环状碳酸酯，基于所述电解液的总质量，所述氟代醚与所述氟代羧酸酯的质量百分含量之和与所述非氟代羧酸酯的质量百分含量比值为Z，Z满足：0.8≤Z≤2，例如，Z可以为0.8、0.9、1.0、1.1、1.2、1.3、1.4、1.5、1.6、1.7、1.8、1.9、2.0或为其间的任何范围，当非氟代羧酸酯质量百分含量较高时(Z小于0.8)，电解液稳定性变差；当非氟代羧酸酯质量百分含量较低时(Z大于2)，氟代物质的质量百分含量增大使电解液整体粘度增大，同时影响到锂盐的解离，导致电化学装置性能恶化，使氟代醚与氟代羧酸酯的质量百分含量之和与非氟代羧酸酯的质量百分含量满足上述关系式，以更好的发挥二者的协同关系，可以使电解液具有更好的动力学性能，将本申请的电解液应用于高压电化学装置，可以改善高压电化学装置的循环寿命；
(2)所述电解液还包含非氟代羧酸酯和环状碳酸酯，基于所述电解液的总质量，所述非氟代羧酸酯的质量百分含量和所述环状碳酸酯的质量百分含量的比值为Y，0.5≤Y≤1，例如，Y可以为0.5、0.55、0.6、0.65、0.7、0.75、0.8、0.85、0.9、0.95、1或为其间的任何范围。不限于任何理论，本申请人发现，使非氟代羧酸酯的质量百分含量和环状碳酸酯质量百分含量满足上述关系式，以更好的发挥二者的协同关系，可以使电解液具有更好的动力学性能和粘度，将本申请的电解液应用于高压电化学装置，可以改善高压电化学装置的循环寿命。
不限于任何理论，本申请人发现，通过协同控制非氟代羧酸酯和环状碳酸酯满足上述条件中的一种或两种组合，可以使本申请的电解液应用于高压电化学装置时，进一步改善高压电化学装置的循环寿命。
本申请对环状碳酸酯没有特别限制，只要能够实现本申请目的即可，例如，环状碳酸酯可以包括但不限于碳酸亚乙酯、碳酸亚丙酯、三亚甲基环碳酸酯、2,2-二甲基三亚甲基环碳酸酯中的至少一种。
本申请对非氟代羧酸酯没有特别限制，只要能够实现本申请的目的即可，例如，非氟代羧酸酯可以包括但不限于甲酸甲酯、甲酸乙酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、γ-丁内酯、癸内酯、戊内酯或己内酯中的至少一种。
本申请的一种实施方案中，所述电解液中还包含通式(III)表示的磺酸内酯，基于所述电解液的总质量，所述磺酸内酯的质量百分含量与所述氟代羧酸酯的质量百分含量比值为K，0.18≤K≤0.9，例如，K可以为0.18、0.25、0.35、0.45、0.55、0.65、0.75、0.85、0.90或为其间的任何范围：
Figure PCTCN2022122142-appb-000004
其中，
R 5可以选自单键、C 1至C 3的亚烷基；
R 6、R 7和R 8各自独立地选自H、卤素、含有不饱和键的C 2-C 5烃基。当磺酸内酯质量百分含量较低时(K小于0.18)，在负极上成膜使负极阻抗增加，导致锂离子嵌入和脱离困难；当磺酸内酯质量百分含量较高时(K大于0.9)，由于磺酸内酯在负极界面持续反应，导致界面阻抗增加，影响锂离子的嵌入和脱离，因此使磺酸内酯质量百分含量与氟代羧酸酯质量百分含量满足上述关系式，将本申请的电解液应用于高压电化学装置，可以改善高压电化学装置的循环寿命。
本申请的一种实施方案中，所述通式(III)表示的磺酸内酯包含下式(III-1)至(III-6)中的至少一种：
Figure PCTCN2022122142-appb-000005
不限于任何理论，本申请人发现，当选择上述磺酸内酯时，将本申请的电解液应用于高压电化学装置，能进一步改善高压电化学装置的循环寿命。
本申请的一种实施方案中，所述电解液包括通式(IV)表示的碳酸亚乙烯酯，基于所述电解液的总质量，所述碳酸亚乙烯酯的质量百分含量和所述氟代羧酸酯的质量百分含量比值为M，0.008≤M≤0.2，例如，M可以为0.008、0.02、0.04、0.06、0.08、0.1、0.12、0.14、0.16、0.18、0.2或为其间的任何范围：
Figure PCTCN2022122142-appb-000006
其中，
R 9和R 10各自独立地选自H、卤素、含有不饱和键的C 2-C 5烃基。当碳酸亚乙烯酯质量百分含量较少时(M小于0.008)，无法有效抑制氟代羧酸酯在负极界面的反应；当碳酸亚乙烯酯质量百分含量较多时(M大于0.2)，增加了负极界面阻抗，锂离子传输过程恶化，因此控制碳酸亚乙烯酯质量百分含量与氟代羧酸酯质量百分含量的比值在上述范围内，将本申请的电解液应用于高压电化学装置，能进一步改善高压电化学装置的循环寿命。
本申请的一种实施方案中，所述通式(IV)表示的碳酸亚乙烯酯包含下式(IV-1)至(IV-4)中的至少一种：
Figure PCTCN2022122142-appb-000007
不限于任何理论，本申请人发现，当选择上述碳酸亚乙烯酯时，将本申请的电解液应用于高压电化学装置，能进一步改善高压电化学装置的循环寿命。
本申请的一种实施方案中，所述电解液进一步包含通式(V)表示的腈类化合物，基于所述电解液的总质量，所述腈类化合物的质量百分含量与所述氟代羧酸酯的质量百分含量比值为L，0.02≤L≤0.8，例如，L可以为0.02、0.1、0.2、0.3、0.4、0.5、0.6、0.7、0.8或为其间的任何范围：
Figure PCTCN2022122142-appb-000008
其中，
n选自1-3的整数；
R 11、R 12、R 13、R 14各自独立地选自H、取代或未经取代的C 1至C 10烷基、取代或未经取代的式(V-A)所示的基团、取代或未经取代的式(V-B)所示的基团、取代或未经取代的式(V-C)所示的基团、取代或未经取代的式(V-D)所示的基团、取代或未经取代的式(V-E) 所示的基团、取代或未经取代的C 2-C 10的烷氧基羰基，经取代时，各取代基各自独立地选自卤素：
Figure PCTCN2022122142-appb-000009
a、b、c、d、e、f、g、h、i、j、k各自独立地选自0-10的整数；
所述R 11、R 12、R 13、R 14中的至少两个选自含有氰基的基团。
当腈类化合物的质量百分含量较低时(L小于0.02)，对正极界面保护不足，导致电解液在正极界面消耗不均匀，对电化学装置循环性能改善不明显；当腈类化合物的质量百分含量较高时(L大于0.8)，正极界面的阻抗增加，阻碍锂离子传输过程，因此选择上述腈类化合物，控制腈类化合物质量百分含量与氟代羧酸酯质量百分含量的比值在上述范围内，将本申请的电解液应用于高压电化学装置时，可以改善高压电化学装置的循环寿命。
本申请的一种实施方案中，所述通式(V)表示的腈类化合物包含下式(V-1)至(V-10)中的至少一种：
Figure PCTCN2022122142-appb-000010
Figure PCTCN2022122142-appb-000011
不限于任何理论，本申请人发现，通过选择上述腈类化合物，将本申请的电解液应用于高压电化学装置时，可以进一步改善高压电化学装置的循环寿命。
本申请的一种实施方案中，所述电解液还包含二氟草酸硼酸锂(LiBOB)，基于所述电解液的总质量，所述二氟草酸硼酸锂的质量百分含量与所述氟代羧酸酯的质量百分含量比值为H，H满足：0.004≤H≤0.2，例如，H可以为0.004、0.008、0.025、0.045、0.065、0.085、0.105、0.125、0.145、0.165、0.185、0.2或为其间的任何范围。当电解液中二氟草酸硼酸锂的质量百分含量过低时(H小于0.004)，无法在正负极界面形成稳定的保护膜，起不到有效的保护效果；当二氟草酸硼酸锂的质量百分含量过高时(H大于0.2)，会引起电化学装置安全性能恶化，因此控制二氟草酸硼酸锂质量百分含量与氟代羧酸酯质量百分含量的比值在上述范围内，将本申请的电解液应用于高压电化学装置时，可以进一步改善高压电化学装置的循环寿命。
本申请的一种实施方案中，所述电解液包含通式(VI)或通式(VII)表示的硫酸乙烯酯，基于所述电解液的总质量，所述硫酸乙烯酯的质量百分含量与所述氟代羧酸酯的质量百分含量比值为N，0.012≤N≤0.2，例如，N可以为0.012、0.02、0.04、0.06、0.08、0.1、0.12、0.14、0.16、0.18、0.2或为其间的任何范围：
Figure PCTCN2022122142-appb-000012
其中，
W选自
Figure PCTCN2022122142-appb-000013
m为1至4的整数，n为0至2的整数，p为0至6的整数；
M选自单键或亚甲基；
R 15和R 16各自独立地选自H、C 1至C 6的烷基、式(VII-A)所示的基团或式(VII-B)所示的基团：
Figure PCTCN2022122142-appb-000014
R 17选自卤素、C 1至C 6的卤代烷基、C 1至C 6的烷氧基。不限于任何理论，本申请人发现，当硫酸乙烯酯质量百分含量较低时(N小于0.012)，无法在负极表面形成稳定的固体电解质(SEI)膜；当硫酸乙烯酯质量百分含量较高时(N大于0.2)，容易引发电解液酸度偏高，导致对正极界面的加速腐蚀，同时影响到SEI膜的致密性，从而影响到界面的稳定性。因此协同控制硫酸乙烯酯质量百分含量与氟代羧酸酯质量百分含量的比值在上述范围内，将本申请的电解液应用于高压电化学装置时，可以改善高压电化学装置的循环寿命。
本申请的一种实施方案中，所述通式(VI)或通式(VII)表示的硫酸乙烯酯包括下式(VI-1)至(VI-4)、(VII-1)至(VII-4)中的至少一种：
Figure PCTCN2022122142-appb-000015
不限于任何理论，本申请人发现，选择上述硫酸乙烯酯时，将本申请的电解液应用于高压电化学装置，可以进一步改善高压电化学装置的循环寿命。
在本申请中，所述电解液还包含锂盐，本申请对锂盐没有特别限制，只要能够实现本申请的目的即可，例如所述锂盐可以包括但不限于六氟磷酸锂、四氟硼酸锂、六氟砷酸锂、高氯酸锂、双氟磺酰亚胺锂、双三氟甲烷磺酰亚胺锂中的至少一种，基于所述电解液的总质量，所述锂盐的质量百分含量为10％至20％，例如可以为10％、12％、14％、16％、18％、20％或为其间的任何范围。
本申请第二方面提供了一种电化学装置，包括正极、负极和本申请第一方面提供的电解液。本申请提供的电解液在高压下具有良好的稳定性，从而本申请提供的电化学装置具有较长的使用寿命和良好的循环性能。
在本申请第二方面的一种实施方案中，所述电化学装置满足如下特征中的至少一种：
(1)所述正极包含正极活性材料，所述正极活性材料中包含铝元素，基于所述正极活性材料的总质量，所述铝元素的质量百分含量为A％，A的取值范围为0.01至1，例如 可以为0.01、0.05、0.15、0.25、0.35、0.45、0.55、0.65、0.75、0.85、0.95、1或为其间的任何范围，本申请人发现，正极活性材料表面铝元素的质量百分含量过高时(A大于1)，正极脱嵌锂离子阻抗明显增加，正极活性材料的动力学性能恶化；正极活性材料表面铝元素的质量百分含量过低时(A小于0.01)，对正极活性材料优化不明显，导致电化学装置循环过程无明显改善，通过将铝元素的质量百分含量控制在上述范围内，更有利于高压电化学装置循环性能的改善；
(2)所述正极包含正极活性材料，所述正极活性材料进一步包含镧、锆、铌或钛元素，基于所述正极活性材料的总质量，所述镧、锆、铌或钛元素的质量百分含量为B％，B的取值范围为0.01至0.8，例如B可以为0.01、0.05、0.1、0.15、0.2、0.25、0.3、0.35、0.4、0.45、0.5、0.55、0.6、0.65、0.7、0.75、0.8或为其间的任何范围，不限于任何理论，本申请人发现，控制正极活性材料中镧、锆、铌或钛元素的质量百分含量在上述范围内，有利于改善正极界面的动力学性能，从而进一步改善高压电化学装置的循环性能；
(3)所述正极包含正极活性材料，所述正极活性材料中包含镧、锆、铌或钛元素，基于所述正极活性材料的总质量，所述镧、锆、铌或钛元素的质量百分含量为B％，B/A满足：0.01≤B/A≤0.8，例如可以为0.01、0.05、0.1、0.15、0.2、0.25、0.3、0.35、0.4、0.45、0.5、0.55、0.6、0.65、0.7、0.75、0.8或为其间的任何范围，不限于任何理论，本申请人发现，使镧、锆、铌或钛元素含量和铝元素含量满足上述关系式，更有利于改善正极界面的动力学性能，能够有效地在正极表面形成稳定的保护层，降低正极界面的副反应，从而改善高压电化学装置的循环性能；
(4)所述负极的负极活性材料颗粒Dv50为8μm至20μm，例如，Dv50可以为8μm、12μm、14μm、16μm、18μm、20μm或为其间的任何范围，不限于任何理论，本申请人发现，当负极活性材料的颗粒尺寸在上述范围内时，负极活性材料具有很好的动力学性能，并且不会影响到负极的压实密度，更有利于高压电化学装置循环性能的改善。
不限于任何理论，本申请发现，通过协同控制电化学装置满足上述条件中的一种、两种或两种以上的组合，能够改善高压电化学装置的循环性能。
在本申请中，正极活性材料中铝元素和镧、锆、铌或钛元素的掺杂方式没有特殊要求，可以通过铝盐、镧盐、锆盐、铌盐或钛盐与钴酸锂、锂镍锰钴三元材料、磷酸铁锂、镍锰酸锂中的至少一种按照目标元素比例含量混合后，进行烧结得到相应的正极活性材料。
正极极片通常包括正极集流体，在本申请中，正极集流体没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于铝箔、铝合金箔或复合集流体等。在本申请中，对正极集流体的厚度没有特别限制，只要能够实现本申请目的即可，例如厚度为8μm至12μm。在本申请中，正极材料层可以设置于正极集流体厚度方向上的一个表面上，也可以设置于正极集流体厚度方向上的两个表面上。需要说明，这里的“表面”可以是正极集流体的全部区域，也可以是正极集流体的部分区域，本申请没有特别限制，只要能实现本申 请目的即可。
在本申请中，正极材料层中包括本申请前述任一实施方案中的正极活性材料，正极材料层还可以包括粘结剂，本申请对粘结剂没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于聚丙烯酸、聚丙烯酸钠、聚丙烯酸钾、聚丙烯酸锂、聚酰亚胺、聚乙烯醇、羧甲基纤维素、羧甲基纤维素钠、聚酰亚胺、聚酰胺酰亚胺、丁苯橡胶或聚偏氟乙烯中的至少一种。
在本申请中，正极材料层中还可以包括导电剂，本申请对导电剂没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于导电炭黑(Super P)、碳纳米管(CNTs)、碳纤维、鳞片石墨、科琴黑、石墨烯、金属材料或导电聚合物中的至少一种。上述碳纳米管可以包括但不限于单壁碳纳米管和/或多壁碳纳米管。上述碳纤维可以包括但不限于气相生长碳纤维(VGCF)和/或纳米碳纤维。上述金属材料可以包括但不限于金属粉和/或金属纤维，具体地，金属可以包括但不限于铜、镍、铝或银中的至少一种。上述导电聚合物可以包括但不限于聚亚苯基衍生物、聚苯胺、聚噻吩、聚乙炔或聚吡咯中的至少一种。
任选地，正极还可以包括导电层，导电层位于正极集流体和正极材料层之间。本申请对导电层的组成没有特别限制，可以是本领域常用的导电层，例如可以包括但不限于上述导电剂和上述粘结剂。
本申请中的负极极片没有特别限制，只要能实现本申请的目的即可，例如负极极片通常包括负极集流体和负极材料层。在本申请中，负极材料层可以设置于负极集流体厚度方向上的一个表面上，也可以设置于负极集流体厚度方向上的两个表面上。需要说明，这里的“表面”可以是负极集流体的全部区域，也可以是负极集流体的部分区域，本申请没有特别限制，只要能实现本申请目的即可。
本申请中，负极集流体没有特别限制，只要能够实现本申请目的即可，例如，可以包括但不限于铜箔、铜合金箔、镍箔、不锈钢箔、钛箔、泡沫镍、泡沫铜或复合集流体等。在本申请中，对负极的集流体的厚度没有特别限制，只要能够实现本申请目的即可，例如厚度为4μm至12μm。
本申请中，负极材料层包括负极活性材料，其中，负极活性材料没有特别限制，只要能实现本申请的目的即可，例如可以包括但不限于天然石墨、人造石墨、中间相微碳球、硬碳、软碳、硅、硅-碳复合物、Li-Sn合金、Li-Sn-O合金、Sn、SnO、SnO 2、尖晶石结构的锂化TiO 2-Li 4Ti 5O 12或Li-Al合金中的至少一种。
在本申请中，负极材料层中还可以包括导电剂，本申请对导电剂没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于上述导电剂中的至少一种。
在本申请中，负极材料层中还可以包括粘结剂，本申请对粘结剂没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于上述粘结剂中的至少一种。
任选地，负极还可以包括导电层，导电层位于负极集流体和负极材料层之间。本申请 对导电层的组成没有特别限制，可以是本领域常用的导电层，导电层可以包括但不限于上述导电剂和上述粘结剂。
本申请对隔离膜没有特别限制，只要能够实现本申请目的即可，例如可以包括但不限于聚乙烯(PE)、聚丙烯(PP)、聚四氟乙烯为主的聚烯烃(PO)类隔膜、聚酯膜(例如聚对苯二甲酸二乙酯(PET)膜)、纤维素膜、聚酰亚胺膜(PI)、聚酰胺膜(PA)、氨纶、芳纶膜、织造膜、非织造膜(无纺布)、微孔膜、复合膜、隔膜纸、碾压膜或纺丝膜中的至少一种，优选为PP。本申请的隔离膜可以具有多孔结构，孔径的尺寸没有特别限制，只要能实现本申请的目的即可，例如，孔径的尺寸可以为0.01μm至1μm。在本申请中，隔离膜的厚度没有特别限制，只要能实现本申请的目的即可，例如厚度可以为5μm至500μm。
例如，隔离膜可以包括基材层和表面处理层。基材层可以为具有多孔结构的无纺布、膜或复合膜，基材层的材料可以包括但不限于聚乙烯、聚丙烯、聚对苯二甲酸乙二醇酯或聚酰亚胺中的至少一种。任选地，可以使用聚丙烯多孔膜、聚乙烯多孔膜、聚丙烯无纺布、聚乙烯无纺布或聚丙烯-聚乙烯-聚丙烯多孔复合膜。任选地，基材层的至少一个表面上设置有表面处理层，表面处理层可以是聚合物层或无机物层，也可以是混合聚合物与无机物所形成的层。
无机物层可以包括但不限于无机颗粒和无机物层粘结剂，本申请对无机颗粒没有特别限制，例如，可以包括但不限于氧化铝、氧化硅、氧化镁、氧化钛、二氧化铪、氧化锡、二氧化铈、氧化镍、氧化锌、氧化钙、氧化锆、氧化钇、碳化硅、勃姆石、氢氧化铝、氢氧化镁、氢氧化钙或硫酸钡中的至少一种。本申请对无机物层粘结剂没有特别限制，例如，可以包括但不限于聚偏氟乙烯、偏氟乙烯-六氟丙烯的共聚物、聚酰胺、聚丙烯腈、聚丙烯酸酯、聚丙烯酸、聚丙烯酸盐、聚乙烯呲咯烷酮、聚乙烯醚、聚甲基丙烯酸甲酯、聚四氟乙烯或聚六氟丙烯中的至少一种。聚合物层中包含聚合物，聚合物的材料可以包括但不限于聚酰胺、聚丙烯腈、丙烯酸酯聚合物、聚丙烯酸、聚丙烯酸盐、聚乙烯呲咯烷酮、聚乙烯醚、聚偏氟乙烯或聚(偏氟乙烯-六氟丙烯)中的至少一种。
本申请的电化学装置没有特别限制，其可以包括发生电化学反应的任何装置。在一些实施方案中，电化学装置可以包括但不限于：锂金属二次电池、锂离子二次电池(锂离子电池)、锂聚合物二次电池或锂离子聚合物二次电池等。
电化学装置的制备过程为本领域技术人员所熟知的，本申请没有特别的限制，例如，可以包括但不限于以下步骤：将正极极片、隔离膜和负极极片按顺序堆叠，并根据需要将其卷绕、折叠等操作得到卷绕结构的电极组件，将电极组件放入包装袋内，将电解液注入包装袋并封口，得到电化学装置；或者，将正极、隔离膜和负极按顺序堆叠，然后用胶带将整个叠片结构的四个角固定好得到叠片结构的电极组件，将电极组件置入包装袋内，将电解液注入包装袋并封口，得到电化学装置。此外，也可以根据需要将防过电流元件、导板等置于包装袋中，从而防止电化学装置内部的压力上升、过充放电。
本申请第三方面提供了一种电子装置，包含本申请第二方面提供的电化学装置。本申请提供的电化学装置具有良好的循环性能，从而本申请提供的电子装置具有较长的使用寿命和良好的性能。
本申请的电子装置没有特别限定，其可以是用于现有技术中已知的任何电子装置。在一些实施例中，电子装置可以包括，但不限于，笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池和锂离子电容器等。
本申请提供一种电解液、包含该电解液的电化学装置及电子装置，通过在电解液中引入氟代物质，利用氟原子很强的电负性和弱极性，被氟化的物质具有较高的氧化电位，可以有效的提高电解液的氧化性窗口，有效降低溶剂在正极界面的氧化分解，降低电解液在循环过程中的溶剂消耗，从而改善高压电化学装置的循环寿命。因此，对发展高能量密度的电能储能器件，具有广阔的应用前景。
具体实施方式
为使本申请的目的、技术方案、及优点更加清楚明白，以下参照实施例，对本申请进一步详细说明。显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员所获得的所有其他技术方案，都属于本申请保护的范围。
需要说明的是，本申请的具体实施方式中，以锂离子电池作为电化学装置的例子来解释本申请，但是本申请的电化学装置并不仅限于锂离子电池。
测试方法和设备：
高温存储性能测试：
在25℃下，将锂离子电池静置30min，然后以0.5C倍率恒流充电至4.55V，再在4.55V下恒压充电至0.05C，静置5min，测试锂离子电池的厚度(以此为存储前的厚度)然后在85℃下储存8h，测量锂离子电池厚度(以此为存储后厚度)，计算锂离子电池厚度膨胀率：
厚度膨胀率＝[(存储后厚度-存储前厚度)/存储前厚度]×100％。
高温循环性能测试：
在45℃下，将锂离子电池以1.3C恒流充电至4.2V，然后再以0.5C恒流充电至4.55V，最后恒压充电至电流为0.05C，再用0.5C恒流放电至3.0V，此为首次循环。按照上述条件使锂离子电池进行多次循环。以首次放电的容量为100％，反复进行充放电循环，至放电容量保持率衰减至80％时，停止测试，记录循环圈数，作为评价锂离子电池循环性能的指标。
颗粒尺寸的测试：
利用MasterSizer 2000测试负极活性材料的粒度累积分布曲线。Dv50为颗粒采用激光散射粒度仪测试得到的体积基准分布中累积50％的直径。
元素含量的测试：
使用刀片将附着在正极集流体上的正极活性材料刮下，待测试。
在25℃下，将1g待测样品粉末加入到100ml浓度为3％的盐酸溶液中，在25℃下恒温消解4h，然后将溶液过滤后分别取滤液和过滤残渣。
通过以下方法测试样品的表面区域的元素含量：将滤液定容到200ml，利用电感耦合等离子体发射光谱仪(ICP-OES)测试滤液中铝元素和镧元素的含量。
通过以下方法测试样品的元素含量：将过滤残渣加入到10ml王水中完全消解，将消解后的溶液定容到50ml，利用ICP-OES测试消解液中镧元素的含量。
实施例1-1
(1)电解液的制备
在含水量<10ppm的氩气气氛手套箱中，将碳酸亚乙酯(EC)、碳酸亚丙酯(PC)、丙酸乙酯(EP)按质量比1:1:1均匀混合，形成基础溶剂，然后按照表1所示加入氟代羧酸酯(I-1)、氟代醚(II-1)和氟代碳酸乙烯酯(FEC)，得到溶剂，各种物质的质量百分含量、相关参数和性能如表1所示。最后加入LiPF 6溶解并搅拌均匀，形成电解液，基于电解液的总质量，LiPF 6的质量百分含量为12.5％，余量为基础溶剂。其中，Y值为0.5。
(2)正极极片的制备
将正极活性材料Al掺杂量为0.01％的正极活性物质(LiCoO 2)、导电剂碳(Super p)、粘结剂(聚偏二氟乙烯)按照重量比95:2:3进行混合，加入N-甲基吡咯烷酮(NMP)，在真空搅拌机作用下搅拌至体系成均一状、固含量为75wt％的正极浆料，将正极浆料均匀涂覆于厚度为12μm的正极集流体铝箔上，在85℃条件下烘干，冷压后得到正极活性材料层厚度为100μm的正极极片，然后在该正极极片的另一个表面上重复以上步骤，得到双面涂布有正极活性材料层的正极极片。将正极极片裁切成74mm×867mm的规格并焊接极耳后待用。
(3)负极极片的制备
将负极活性材料人造石墨(Dv50＝10μm)、丁苯橡胶(SBR)及羧甲基纤维素钠(CMC)按质量比97.4:1.2:1.4混合，然后加入去离子水作为溶剂，调配成固含量为70wt％的浆料，并搅拌均匀。将浆料均匀涂布在厚度为8μm的铜箔的一个表面上，110℃条件下烘干，冷压后得到负极活性材料层厚度为150μm的单面涂布负极活性材料层的负极极片，然后在该负极极片的另一个表面上重复以上涂布步骤，得到双面涂布有负极活性材料层的负极极片。将负极极片裁切成76mm×851mm的规格并焊接极耳后待用。
(4)隔离膜
以聚乙烯(PE)多孔聚合物薄膜作为隔离膜。
(5)锂离子电池的制备
将正极片、隔离膜、负极片按顺序叠好，使隔离膜处于正极片和负极片之间起到隔离的作用，然后卷绕，尾部收尾贴胶，置于冲好的铝箔袋中，将铝箔袋边缘封装，然后放置在85℃真空烘箱中干燥12h，将干电芯中的水分去除，最后将上述制备好的电解液注入到真空干燥后的电池中，经过真空封装、静置、化成、成形等工序，即完成锂离子电池的制备。
实施例1-2至实施例1-7
除了按照表1调整各溶剂的种类和质量百分含量以外，其余与实施例1-1相同。
对比例1-1至对比例1-4
除了按照表1调整各溶剂的种类和质量百分含量以外，其余与实施例1-1相同。
表1
Figure PCTCN2022122142-appb-000016
注：表1中，“/”表示不存在相关制备参数。
从实施例1-1至实施例1-7和对比例1-1至对比例1-4可以看出，氟代羧酸酯、氟代醚和FEC会影响高压锂离子电池的高温循环性能和高温存储性能。选用同时含有氟代羧酸酯、氟代醚和FEC三种物质，且上述物质均在本申请权利要求1范围内的高压锂离子电池，能够有良好的高温循环和高温存储性能。
氟代羧酸酯质量百分含量和氟代醚质量百分含量的比值通常也会影响高压锂离子电池的高温循环性能和高温存储性能，从实施例1-1至实施例1-7中可以看出，选用氟代羧 酸酯的质量百分含量和氟代醚质量百分含量的比值在本申请范围内的高压锂离子电池，能够有更好的高温循环性能和高温存储性能。
氟代羧酸酯和氟代醚质量百分含量的总和与非氟代羧酸酯质量百分含量的比值Z，通常也会影响高压锂离子电池的高温循环性能和高温存储性能，从实施例1-1至实施例1-7中可以看出，选用Z的取值在本申请范围内的高压锂离子电池，能够有更好的高温循环性能和高温存储性能。
FEC质量百分含量与氟代羧酸酯和氟代醚质量百分含量之和的比值X通常也会影响高压锂离子电池的高温循环性能和高温存储性能，从实施例1-1至实施例1-3和实施例1-5至实施例1-7中可以看出，选用X的取值在本申请范围内的高压锂离子电池，能够有更好的高温循环性能和高温存储性能。
实施例2-1至实施例2-13
除了按照表2调整磺酸内酯的种类和质量百分含量以外，其余与实施例1-2相同。
表2
Figure PCTCN2022122142-appb-000017
从实施例2-1至实施例2-13可以看出，磺酸内酯通常也会影响高压锂离子电池的高温循环性能和高温存储性能，从实施例2-4至实施例2-6、实施例2-8至实施例2-10和实施例2-12至实施例2-13可以看出，选用包含通式(III)表示的磺酸内酯，并且磺酸内酯质量百分含量与氟代羧酸酯质量百分含量的比值K在本申请范围内的高压锂离子电池，能够有更好的的高温循环性能和高温存储性能。
实施例3-1至实施例3-11
除了按照表3调整碳酸亚乙烯酯的种类和质量百分含量以外，其余与实施例1-2相同。
表3
Figure PCTCN2022122142-appb-000018
从实施例3-1至实施例3-11可以看出，通式(IV)表示的碳酸亚乙烯酯通常也会影响高压锂离子电池的高温循环性能。从实施例3-2至实施例3-5和实施例3-7至实施例3-11可以看出，选用包含通式(IV)表示的碳酸亚乙烯酯，并且碳酸亚乙烯酯质量百分含量与氟代羧酸酯质量百分含量的比值M在本申请范围内的高压锂离子电池，能够有更好的高温循环性能。
实施例4-1至实施例4-18
除了按照表4调整腈类化合物的种类和质量百分含量以外，其余与实施例1-2相同。
表4
Figure PCTCN2022122142-appb-000019
Figure PCTCN2022122142-appb-000020
从实施例4-1至实施例4-18可以看出，通式(V)表示的腈类化合物通常也会影响高压锂离子电池的高温循环性能和高温存储性能。从实施例4-1至实施例4-18可以看出，选用包含通式(V)表示的腈类化合物，并且腈类化合物质量百分含量与氟代羧酸酯质量百分含量的比值L在本申请范围内的高压锂离子电池，能够有更好的高温循环性能和高温存储性能。
实施例5-1至实施例5-5
除了按照表5调整LiBOB的种类和质量百分含量以外，其余与实施例1-2相同。
表5
Figure PCTCN2022122142-appb-000021
从实施例5-1至实施例5-5可以看出，电解液中LiBOB通常也会影响高压锂离子电池的高温循环性能。从实施例5-1至实施例5-5中可以看出，选用添加LiBOB，并且LiBOB质量百分含量与氟代羧酸酯质量百分含量的比值H在本申请范围内的高压锂离子电池，能够有良好的高温循环性能。
实施例6-1至实施例6-14
除了按照表6调整硫酸乙烯酯的种类和质量百分含量以外，其余与实施例1-2相同。
表6
Figure PCTCN2022122142-appb-000022
注：表6中“/”表示无相关制备参数。
从实施例6-1至实施例6-14可以看出，通式(VI)和通式(VII)表示的硫酸乙烯酯通常也会影响高压锂离子电池的高温循环性能和高温存储性能。从实施例6-2至实施例6-14可以看出，选用包含通式(VI)和通式(VII)表示的硫酸乙烯酯，并且硫酸乙烯酯质量百分含量与氟代羧酸酯质量百分含量的比值N在本申请范围内的高压锂离子电池，能够有良好的高温循环性能和高温存储性能。
实施例7-1至实施例7-29
除了按照表7调整各种添加剂的种类和质量百分含量以外，其余与实施例1-2相同。
表7
Figure PCTCN2022122142-appb-000023
注：表7中，“/”表示无相关制备参数。
从实施例7-1至实施例7-29中可以看出，在使用氟代羧酸酯、氟代醚和FEC的基础上，在电解液中加入磺酸内酯、碳酸亚乙烯酯、腈类化合物、LiBOB、硫酸乙烯酯中的至少两种，起到了很好的协同效果，能够更有效的改善高压锂离子电池的高温循环和高温存储性能。
以上所述仅为本申请的较佳实施例，并非用于限定本申请的保护范围。凡在本申请的精神和原则之内所作的任何修改、等同替换、改进等，均包含在本申请的保护范围内。

Claims (16)

  1. 一种电解液，其包括氟代碳酸乙烯酯、通式(I)表示的氟代羧酸酯和通式(II)表示的氟代醚：
    Figure PCTCN2022122142-appb-100001
    其中，
    R 1和R 2各自独立地选自C 1至C 5的烷基、氟取代的C 1至C 5的烷基、磺酸基取代的C 2至C 5的烷基、氰基取代的C 2至C 5的烷基，且R 1和R 2中至少一个为氟取代的C 1至C 5的烷基；
    R 3和R 4各自独立地选自C 1至C 5的烷基、氟取代的C 1至C 5的烷基、磺酸基取代的C 2至C 5的烷基、氰基取代的C 2至C 5的烷基，且R 3和R 4中至少一个为氟取代的C 1至C 5的烷基。
  2. 根据权利要求1所述的电解液，其中，所述通式(I)表示的氟代羧酸酯包括下式(I-1)至(I-4)中的至少一种：
    Figure PCTCN2022122142-appb-100002
    所述通式(II)表示的氟代醚包括下式(II-1)至(II-4)中的至少一种：
    Figure PCTCN2022122142-appb-100003
  3. 根据权利要求1所述的电解液，其满足如下特征中的至少一种：
    (1)基于所述电解液的总质量，所述氟代羧酸酯的质量百分含量为10％至20％；
    (2)基于所述电解液的总质量，所述氟代醚的质量百分含量为5％至15％；
    (3)基于所述电解液的总质量，所述氟代醚的质量百分含量与所述氟代羧酸酯的质量百分含量满足：所述氟代醚的质量百分含量/所述氟代羧酸酯的质量百分含量≤2/3；
    (4)基于所述电解液的总质量，所述氟代碳酸乙烯酯的质量百分含量与所述氟代醚和所述氟代羧酸酯的质量百分含量之和的比值为X，0.1≤X≤0.6。
  4. 根据权利要求1所述的电解液，其满足如下特征中的至少一种：
    (1)所述电解液包含非氟代羧酸酯和环状碳酸酯，基于所述电解液的总质量，所述氟代醚和所述氟代羧酸酯的质量百分含量之和与非氟代羧酸酯的质量百分含量比值为Z，Z满足：0.8≤Z≤2；
    (2)所述电解液包含非氟代羧酸酯和环状碳酸酯，基于所述电解液的总质量，所述非氟代羧酸酯的质量百分含量和所述环状碳酸酯的质量百分含量的比值为Y，0.5≤Y≤1。
  5. 根据权利要求1所述的电解液，其中，所述电解液还包含通式(III)表示的磺酸内酯，基于所述电解液的总质量，所述磺酸内酯的质量百分含量与所述氟代羧酸酯的质量百分含量比值为K，0.18≤K≤0.9：
    Figure PCTCN2022122142-appb-100004
    其中，
    R 5可以选自单键、C 1至C 3的亚烷基；
    R 6、R 7和R 8各自独立地选自H、卤素、含有不饱和键的C 2-C 5烃基。
  6. 根据权利要求5所述的电解液，其中，所述通式(III)表示的磺酸内酯包含下式(III-1)至(III-6)中的至少一种：
    Figure PCTCN2022122142-appb-100005
  7. 根据权利要求1所述的电解液，其中，所述电解液包括通式(IV)表示的碳酸亚乙烯酯，基于所述电解液的总质量，所述碳酸亚乙烯酯的质量百分含量和所述氟代羧酸酯的质量百分含量比值为M，0.008≤M≤0.2：
    Figure PCTCN2022122142-appb-100006
    其中，
    R 9和R 10各自独立地选自H、卤素、含有不饱和键的C 2-C 5烃基。
  8. 根据权利要求7所述的电解液，其中，所述通式(IV)表示的碳酸亚乙烯酯包含下式(IV-1)至(IV-4)中的至少一种：
    Figure PCTCN2022122142-appb-100007
  9. 根据权利要求1所述的电解液，其中，所述电解液进一步包含通式(V)表示的腈类化合物，基于所述电解液的总质量，所述腈类化合物的质量百分含量与所述氟代羧酸酯的质量百分含量比值为L，0.02≤L≤0.8：
    Figure PCTCN2022122142-appb-100008
    其中，
    n选自1-3的整数；
    R 11、R 12、R 13、R 14各自独立地选自H、取代或未经取代的C 1至C 10烷基、取代或未经取代的式(V-A)所示的基团、取代或未经取代的式(V-B)所示的基团、取代或未经取代的式(V-C)所示的基团、取代或未经取代的式(V-D)所示的基团、取代或未经取代的式(V-E)所示的基团、取代或未经取代的C 2-C 10的烷氧基羰基，经取代时，各取代基各自独立地选自卤素：
    Figure PCTCN2022122142-appb-100009
    a、b、c、d、e、f、g、h、i、j、k各自独立地选自0-10的整数；
    所述R 11、R 12、R 13、R 14中的至少两个选自含有氰基的基团。
  10. 根据权利要求9所述的电解液，其中，所述通式(V)表示的腈类化合物包含下式(V-1)至(V-10)中的至少一种：
    Figure PCTCN2022122142-appb-100010
  11. 根据权利要求1所述的电解液，其中，所述电解液还包含二氟草酸硼酸锂，基于所述电解液的总质量，所述二氟草酸硼酸锂的质量百分含量与所述氟代羧酸酯的质量百分含量比值为H，H满足：0.004≤H≤0.2。
  12. 根据权利要求1所述的电解液，其中，所述电解液包含通式(VI)或通式(VII)表示的硫酸乙烯酯，基于所述电解液的总质量，所述硫酸乙烯酯的质量百分含量与所述氟代羧酸酯的质量百分含量比值为N，0.012≤N≤0.2：
    Figure PCTCN2022122142-appb-100011
    其中，
    W选自
    Figure PCTCN2022122142-appb-100012
    m为1至4的整数，n为0至2的整数，p为0至6的整数；
    M选自单键或亚甲基；
    R 15和R 16各自独立地选自H、C 1至C 6的烷基、式(VII-A)所示的基团或式(VII-B)所示的基团：
    Figure PCTCN2022122142-appb-100013
    R 17选自卤素、C 1至C 6的卤代烷基或C 1至C 6的烷氧基。
  13. 根据权利要求12所述的电解液，其中，所述通式(VI)或通式(VII)表示的硫酸乙烯酯包含下式(VI-1)至(VI-4)、(VII-1)至(VII-4)中的至少一种：
    Figure PCTCN2022122142-appb-100014
  14. 一种电化学装置，其包含正极、负极和权利要求1-13任一项所述的电解液。
  15. 根据权利要求14所述的电化学装置，其满足如下特征中的至少一种：
    (1)所述正极包含正极活性材料，所述正极活性材料包含铝元素，基于所述正极活性材料的总质量，所述铝元素的质量百分含量为A％，A的取值范围为0.01至1；
    (2)所述正极包含正极活性材料，所述正极活性材料进一步包含镧、锆、铌或钛元素，基于所述正极活性材料的总质量，所述镧、锆、铌或钛元素的质量百分含量为B％，B的取值范围为0.01至0.8；
    (3)所述正极包含正极活性材料，所述正极活性材料进一步包含镧、锆、铌或钛元素，基于所述正极活性材料的总质量，所述镧、锆、铌或钛元素的质量百分含量为B％，B/A满足：0.01≤B/A≤0.8；
    (4)所述负极的负极活性材料颗粒Dv50为8μm至20μm。
  16. 一种电子装置，其包含权利要求14-15任一项所述的电化学装置。
PCT/CN2022/122142 2021-12-03 2022-09-28 一种电解液、包含该电解液的电化学装置及电子装置 WO2023098268A1 (zh)

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