WO2025199692A1 - 一种电解液、包含该电解液的二次电池及电子装置 - Google Patents

一种电解液、包含该电解液的二次电池及电子装置

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Publication number
WO2025199692A1
WO2025199692A1 PCT/CN2024/083607 CN2024083607W WO2025199692A1 WO 2025199692 A1 WO2025199692 A1 WO 2025199692A1 CN 2024083607 W CN2024083607 W CN 2024083607W WO 2025199692 A1 WO2025199692 A1 WO 2025199692A1
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Prior art keywords
lithium
electrolyte
solvent
present application
additive
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Pending
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PCT/CN2024/083607
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English (en)
French (fr)
Inventor
王美茸
周邵云
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Ningde Amperex Technology Ltd
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Ningde Amperex Technology Ltd
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Priority to PCT/CN2024/083607 priority Critical patent/WO2025199692A1/zh
Publication of WO2025199692A1 publication Critical patent/WO2025199692A1/zh
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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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
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0568—Liquid materials characterised by the solutes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0569—Liquid materials characterised by the solvents
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the field of electrochemical technology, and in particular to an electrolyte, a secondary battery containing the electrolyte, and an electronic device.
  • Secondary batteries such as lithium-ion batteries
  • lithium difluorophosphate has a high solubility.
  • the electrolyte includes lithium difluorophosphate and the first lithium salt and the first solvent, and the values of A, A/B and C are adjusted within the above ranges, which can improve the cycle performance and high-temperature storage performance of the secondary battery.
  • the electrolyte can have a suitable viscosity and a high conductivity, thereby increasing the migration rate of lithium ions and thus being able to be more Good improvement of the cycle performance of secondary batteries.
  • a higher concentration of lithium difluorophosphate will significantly increase the viscosity of the electrolyte and affect the transport of ions in the electrolyte, thereby affecting the cycle performance of the secondary battery.
  • the value of A/B is too small, for example, less than 0.1, the combination of lithium difluorophosphate and the first lithium salt is unreasonable, which is not conducive to the synergistic effect between the two.
  • the stability of the SEI film and CEI film formed at the interface of the positive electrode and the negative electrode is poor.
  • the lithium ions dissociated from the first lithium salt will be solvated with the solvent in the electrolyte.
  • lithium difluorophosphate has a high solubility.
  • the electrolyte includes lithium difluorophosphate and the above-mentioned first lithium salt and first solvent, and regulates the values of A, A/B and C within the above-mentioned range, which can improve the cyclability of the secondary battery. energy and high temperature storage performance.
  • the electrolyte further includes a first additive, the first additive including at least one of 1,3-propane sultone (1,3-PS), 1,3-propylene sultone, vinyl sulfate (VC), 1,3-propylene glycol cyclic sulfate, 2,4-butane sultone (2,4-BS), 1,4-butane sultone (1,4-BS), vinylene carbonate or fluoroethylene carbonate (FEC), and based on the mass of the electrolyte, the mass percentage of the first additive is X 1 %, 0.05 ⁇ X 1 ⁇ 12, for example, the value of X 1 can be 0.05, 0.1, 0.3, 0.8, 1, 3, 5, 6, 8, 10, 12 or a range consisting of any two values therein.
  • the mass percentage of the first additive is X 1 %, 0.05 ⁇ X 1 ⁇ 12, for example, the value of X 1 can be 0.05, 0.1, 0.3, 0.8, 1, 3, 5, 6, 8, 10,
  • the value of A/ X2 can be 2, 3, 5, 8, 10, 12, 18, 20, 24, 25, 28, 30, 33, 35, 37, 40, 44, or a range consisting of any two of these values.
  • the electrolyte of the present application may further include a second solvent.
  • the present application has no particular restrictions on the type of the above-mentioned second solvent, as long as the purpose of the present application can be achieved.
  • it may include but is not limited to at least one of dimethyl carbonate, diethyl carbonate (DEC), dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate or methyl ethyl carbonate.
  • DEC diethyl carbonate
  • the present application has no particular restrictions on the mass percentage of the second solvent, as long as the purpose of the present application can be achieved. For example, based on the mass of the electrolyte, the mass percentage of the second solvent can be 0.2% to 86.75%.
  • the mass percentage of the second solvent can be 0.2%, 2.2%, 5%, 8%, 10%, 12.2%, 14.2%, 17%, 20%, 23%, 26%, 30%, 33%, 35%, 37%, 40%, 43%, 45%, 47%, 50%, 53%, 55%, 58%, 60%, 62%, 66%, 69%, 70%, 72%, 75%, 78%, 80%, 82%, 83%, 85%, 86.6%, 86.75% or a range consisting of any two of the values.
  • the electrolyte includes lithium difluorophosphate, a first lithium salt, a first solvent, and a second solvent, wherein the weight percentages of lithium difluorophosphate, the first lithium salt, and the first solvent are as described above, and the weight percentage of the second solvent is 14.2% to 86.75%.
  • the electrolyte includes lithium difluorophosphate, a first lithium salt, a first solvent, a first additive, and a second solvent.
  • the weight percentages of lithium difluorophosphate, the first lithium salt, the first solvent, and the first additive are as described above, and the weight percentage of the second solvent is 2.2% to 86.7%.
  • Application of the electrolyte having the above characteristics to a secondary battery is beneficial for further improving the cycling performance and high-temperature storage performance of the secondary battery.
  • the electrolyte includes lithium difluorophosphate, a first lithium salt, a first solvent, a first additive, a second additive, and a second solvent, wherein the weight percentages of lithium difluorophosphate, the first lithium salt, the first solvent, the first additive, and the second additive are as described above, and the weight percentage of the second solvent is 0.2% to 86.6%.
  • Application of the electrolyte having the above characteristics to a secondary battery is beneficial for further improving the cycling performance and high-temperature storage performance of the secondary battery.
  • the second aspect of the present application provides a secondary battery, which includes the electrolyte provided by the first aspect of the present application.
  • the secondary battery provided by the present application has good cycle performance and high-temperature storage performance.
  • the secondary battery of the present application also includes a positive electrode sheet.
  • the positive electrode sheet includes a positive electrode collector and a positive electrode material layer provided on at least one surface of the positive electrode collector.
  • the positive electrode material layer can be provided on one surface in the thickness direction of the positive electrode collector, or on two surfaces in the thickness direction of the positive electrode collector.
  • the "surface” here can be the entire area of the surface of the positive electrode collector, or it can be a partial area of the surface of the positive electrode collector.
  • the present application has no special restrictions, as long as the purpose of the present application can be achieved.
  • the secondary battery of the present application also includes a negative electrode plate.
  • the negative electrode plate includes a negative electrode current collector and a negative electrode material layer provided on at least one surface of the negative electrode current collector.
  • the negative electrode material layer can 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 can be the entire area of the negative electrode current collector or a partial area of the negative electrode current collector.
  • the negative electrode material layer of the present application includes a negative electrode active material.
  • the negative electrode active material may include at least one of natural graphite, artificial graphite, mesophase microcarbon beads (MCMBs), hard carbon, soft carbon, silicon, a silicon-carbon composite, SiO x (0 ⁇ x ⁇ 2), a Li-Sn alloy, a Li-Sn-O alloy, Sn, SnO, SnO 2 , spinel lithium titanate (Li 4 Ti 5 O 12 ) , a Li-Al alloy, or metallic lithium.
  • MCMBs mesophase microcarbon beads
  • the thickness of the negative electrode current collector is 4 to 12 ⁇ m
  • the thickness of the single-sided negative electrode material layer is 30 to 160 ⁇ m.
  • the mass ratio of the negative electrode active material, negative electrode conductive agent, and negative electrode binder in the negative electrode material layer there are no particular limitations on the mass ratio of the negative electrode active material, negative electrode conductive agent, and negative electrode binder in the negative electrode material layer, as long as the objectives of this application are achieved.
  • the negative electrode material layer of the present application may also include a negative electrode conductive agent, a negative electrode binder and a negative electrode dispersant.
  • the present application has no particular restrictions on the negative electrode conductive agent and the negative electrode binder, as long as the purpose of the present application can be achieved.
  • the negative electrode conductive agent may include but is not limited to conductive carbon black (Super P), carbon nanotubes (CNTs), graphite, carbon fiber, carbon nanowire, At least one of graphene, metal materials or conductive polymers, the above-mentioned carbon nanotubes may include but are not limited to single-walled carbon nanotubes and/or multi-walled carbon nanotubes.
  • the method for preparing the negative electrode sheet there is no particular limitation on the method for preparing the negative electrode sheet, as long as the purpose of the present application can be achieved.
  • it can be prepared by the following method: a negative electrode active material, a negative electrode binder, and a negative electrode dispersant are mixed, deionized water is added and stirred evenly, and a negative electrode slurry with a solid content of 50wt% to 75wt% is obtained.
  • the negative electrode slurry is evenly coated on one surface of the negative electrode current collector, and after drying, a negative electrode sheet coated with a negative electrode material layer on one side is obtained.
  • the above coating steps are repeated on the other surface of the negative electrode current collector, and after drying, a negative electrode sheet coated with a negative electrode material layer on both sides is obtained.
  • the negative electrode sheet is obtained by cold pressing and cutting.
  • the positive electrode active material includes a compound that reversibly embeds and deintercalates lithium ions.
  • the positive electrode material layer includes a positive electrode active material with a working potential of 4.5V or more relative to metallic lithium. That is, the positive electrode active material of the present application can work under high voltage.
  • the positive electrode active material may include at least one of lithium nickel cobalt manganese oxide (NCM), lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium-rich manganese-based materials, lithium cobalt oxide, lithium manganese oxide, or lithium iron manganese phosphate.
  • the lithium nickel cobalt manganese oxide may include, but is not limited to, at least one of LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523), LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NCM333), or LiNi 0.9 Co 0.05 Mn 0.05 O 2 (NCM955).
  • the above-mentioned positive electrode active materials may be doped.
  • the elements used for doping may include at least one of K, Na, Ca, Mg, B, Al, Co, Si, V, Ga, Sn or Zr.
  • the positive electrode material layer of the present application may also include a positive electrode conductor and a positive electrode binder.
  • the present application has no particular restrictions on the positive electrode conductor and the positive electrode binder, as long as the purpose of the present application can be achieved.
  • the positive electrode conductor may be the same as the above-mentioned negative electrode conductor
  • the positive electrode binder may be the same as the above-mentioned negative electrode binder.
  • the present application has no particular restrictions on the mass ratio of the positive electrode active material, the positive electrode conductor and the positive electrode binder in the positive electrode material layer, as long as it can achieve the purpose of the present application. The purpose of this application is sufficient.
  • the secondary battery of the present application also includes a separator.
  • the present application has no particular restrictions on the separator, as long as it can achieve the purpose of the present application.
  • the material of the separator may include but is not limited to polyethylene (PE), polypropylene (PP), polytetrafluoroethylene-based polyolefin (PO) separators, polyester films (such as polyethylene terephthalate (PET) films), cellulose films, polyimide films (PI), polyamide films (PA), spandex or aramid films, etc.
  • At least one of the types of separators may include but is not limited to woven membranes, non-woven membranes (non-woven fabrics), microporous membranes, composite membranes, rolled membranes or spun membranes, etc.
  • secondary battery may include any device that generates an electrochemical reaction.
  • secondary batteries may include, but are not limited to, lithium metal secondary batteries, lithium ion batteries, sodium ion batteries, lithium polymer secondary batteries, and lithium ion polymer secondary batteries.
  • This application does not specifically limit the shape of the secondary battery, as long as it can achieve the purpose of this application.
  • the secondary battery of this application also includes a packaging bag. This application does not specifically limit the packaging bag, as long as it can achieve the purpose of this application. For example, an aluminum-plastic film packaging bag can be used.
  • the preparation process of a secondary battery is well known to those skilled in the art and is not particularly limited in the present application.
  • it may include but is not limited to the following steps: stacking the positive electrode sheet, the separator and the negative electrode sheet in order, welding the tabs, and then winding, folding and other operations as needed to obtain an electrode assembly with a wound structure, placing the electrode assembly in a packaging bag, injecting the electrolyte into the packaging bag and sealing it to obtain a secondary battery; or, stacking the positive electrode sheet, the separator and the negative electrode sheet in order, welding the tabs, and then fixing the four corners of the entire stacked structure with tape to obtain an electrode assembly with a stacked structure.
  • the battery is then packaged in a plastic bag, the electrode assembly is placed in a packaging bag, the electrolyte is injected into the packaging bag, and the bag is sealed to obtain a secondary battery. Furthermore, overcurrent protection components, guide plates, etc. may be placed in the packaging bag as needed to prevent pressure buildup and overcharge and discharge within the secondary battery.
  • the third aspect of the present application provides an electronic device, which includes the secondary battery provided in the second aspect of the present application.
  • the secondary battery provided in the present application has good cycle performance and high-temperature storage performance, so that the electronic device of the present application has a long service life.
  • the lithium-ion battery was discharged at a constant current of 1C to 2.5V and then disassembled.
  • the electrolyte was collected and the positive electrode, negative electrode and isolation membrane were centrifuged.
  • the liquid obtained after centrifugation was mixed with the above electrolyte.
  • the battery was tested using a gas chromatography-mass spectrometer (instrument model: Agilent 8890) and an ion chromatography (instrument model: AQUION ion chromatography) to obtain the components in the electrolyte and test their contents.
  • the capacity retention rate of lithium-ion batteries is used to evaluate the cycling performance of lithium-ion batteries under high voltage conditions. The higher the capacity retention rate, the better the cycling performance of the lithium-ion battery.
  • the test process is as follows: the lithium-ion battery is placed in a 25°C constant temperature box and allowed to stand for 5 minutes. The lithium-ion battery is then charged at a constant current of 1C to a voltage of 4.28V. Then, the battery is charged at a constant voltage of 4.28V to a current of 0.05C. Finally, the battery is discharged at a constant current of 1C to 2.5V. This is one charge and discharge cycle. The first discharge capacity is recorded as Q 1 . The charge and discharge cycle is repeated 800 times. The test is stopped and the discharge capacity at the 800th time is recorded as Q 2 . The 25°C cycle capacity retention rate (%) of the lithium-ion battery is Q 2 /Q 1 ⁇ 100%.
  • the high temperature storage performance of lithium-ion batteries is evaluated by the thickness expansion rate of lithium-ion batteries stored at 60°C. The lower the rate, the better the lithium-ion battery's high-temperature storage performance.
  • the test process is as follows: In a 25°C environment, the lithium-ion battery is charged at a constant current of 0.5C to 4.28V, then charged at a constant voltage of 4.28V to a current of 0.05C. The thickness of the lithium-ion battery tested is D1 . The lithium-ion battery is then placed in a 60°C oven and removed after 180 days of storage. The thickness of the lithium-ion battery tested at this time is D2 .
  • the thickness expansion rate of the lithium-ion battery stored at 60°C ( D2 - D1 ) / D1 ⁇ 100%.
  • a first solvent, ethyl acetate, and a second solvent, diethyl carbonate were uniformly mixed to obtain an organic solvent.
  • Lithium difluorophosphate and a first lithium salt, lithium hexafluorophosphate (LiPF 6 ) were then sequentially added to the organic solvent, dissolved, and uniformly mixed to obtain an electrolyte.
  • the weight percentages of lithium difluorophosphate (A%), the first lithium salt (B%), and the first solvent (C%), based on the mass of the electrolyte, are as shown in Table 1, with the remainder being the second solvent, diethyl carbonate.
  • the positive electrode active material LiCoO2 , the positive electrode conductive agent conductive carbon black, and the positive electrode binder polyvinylidene fluoride were mixed in a mass ratio of 97:1.4:1.6, and N-methylpyrrolidone was added and stirred evenly to obtain a positive electrode slurry with a solid content of 72 wt%.
  • the positive electrode slurry was evenly coated on one surface of a 10 ⁇ m thick positive electrode current collector aluminum foil.
  • the aluminum foil was then dried at 85°C for 4 hours to obtain a positive electrode sheet coated on one side with a positive electrode material layer.
  • the above steps were repeated on the other surface of the aluminum foil to obtain a positive electrode sheet coated on both sides with a positive electrode material layer.
  • the sheet After drying at 85°C under vacuum for 4 hours, the sheet was cold pressed, cut, and slit to obtain a positive electrode sheet measuring 74 mm x 867 mm.
  • the compacted density of the positive electrode material layer was 4.15 g/ cm3
  • the thickness of the single-sided positive electrode material layer was 60 ⁇ m.
  • the negative electrode active material graphite, the negative electrode binder styrene-butadiene rubber, and the negative electrode thickener sodium carboxymethyl cellulose were mixed in a mass ratio of 97.4:1.4:1.2, and deionized water was added and stirred to obtain a negative electrode slurry with a solid content of 54wt%.
  • the negative electrode slurry was evenly coated on one surface of a negative electrode current collector copper foil with a thickness of 6 ⁇ m.
  • the copper foil was dried at 85°C for 4h to obtain a negative electrode sheet coated with a negative electrode material layer on one side. The above steps were repeated on the other surface of the copper foil.
  • the compacted density of the positive electrode material layer was 1.75 g/ cm3
  • the thickness of the single-sided positive electrode material layer was 70 ⁇ m.
  • PVDF and alumina ceramic were mixed in a 9:1 mass ratio, and deionized water was added as a solvent to prepare a ceramic layer slurry with a solid content of 25wt%.
  • the mixture was stirred evenly and then evenly coated on one surface of a 16 ⁇ m thick polyethylene porous film substrate. After drying, a separator membrane with a 2 ⁇ m alumina ceramic layer coated on one side was obtained. The above coating steps were then repeated on the other surface of the substrate to obtain a separator membrane with a 2 ⁇ m alumina ceramic layer coated on both sides.
  • the prepared positive electrode sheet, separator, and negative electrode sheet are stacked in order, with the separator placed between the positive and negative electrode sheets to act as an insulator, and then wound to form an electrode assembly.
  • the electrode assembly is placed in an aluminum-plastic film packaging bag, placed in an 85°C vacuum oven to dry for 12 hours to remove moisture, and then injected with the prepared electrolyte.
  • vacuum packaging, standing, formation (0.02C constant current charging to 3.5V, then 0.1C constant current charging to 3.9V), shaping, capacity testing, and secondary packaging, a lithium-ion battery is obtained.
  • Example 1-1 The same procedures as in Example 1-1 were used except that the parameters were adjusted according to Table 1.
  • the mass percentage A% of lithium difluorophosphate, the mass percentage B% of the first lithium salt, or the mass percentage C% of the first solvent were changed according to Table 1, the mass percentage of the second solvent was changed accordingly.
  • Example 1-22 The same procedures as in Example 1-22 were used except that the first additive was introduced into the electrolyte and the relevant parameters were adjusted according to Table 2.
  • the mass percentage of lithium difluorophosphate (A%), the mass percentage of the first lithium salt (B%), the mass percentage of the first solvent (C%), or the mass percentage of the first additive ( ⁇ 1 %) was changed according to Table 2, the mass percentage of the second solvent was also changed accordingly.
  • Example 1-22 Except for introducing the second additive into the electrolyte and adjusting the relevant parameters according to Table 3, the rest is the same as Example 1-22.
  • the weight percentage of the second additive ⁇ 2 % is changed according to Table 3, the weight percentage of lithium difluorophosphate (A%), the weight percentage of the first solvent (C%), and the weight percentage of the first lithium salt (B%) remain unchanged, and the weight percentage of the second solvent changes accordingly.
  • Example 2-11 Except for introducing the second additive into the electrolyte and adjusting the relevant parameters according to Table 3, the rest is the same as Example 2-11.
  • the mass percentage of lithium difluorophosphate A% or the mass percentage of the second additive X2 % is changed according to Table 3, The mass percentage C% of the first solvent and the mass percentage B% of the first lithium salt remain unchanged, and the mass percentage of the second solvent changes accordingly.
  • Example 1-1 The same procedures as in Example 1-1 were used except that the parameters were adjusted according to Table 1.
  • the mass percentage A% of lithium difluorophosphate, the mass percentage B% of the first lithium salt, or the mass percentage C% of the first solvent were changed according to Table 1, the mass percentage of the second solvent was changed accordingly.
  • the electrolyte includes lithium difluorophosphate and the first lithium salt and the first solvent of the present application, and regulating the values of A, A/B and C within the scope of the present application, the lithium ion battery can have a lower impedance, a higher cycle capacity retention rate and a lower storage thickness expansion rate, indicating that the lithium ion battery has a lower impedance, better cycle performance and high temperature storage performance.
  • the lithium ion batteries of Comparative Examples 1 to 7 at least one of A, A/B or C is not within the scope of the present application.
  • Comparative Examples 1 and 2 From Examples 1-1 to 1-7, Comparative Examples 1 and 2, it can be seen that when the value of A is too small, such as in Comparative Example 1, the lithium-ion battery's cycle capacity retention rate is lower and the storage thickness expansion rate is higher; when the value of A is too large, such as in Comparative Example 2, the lithium-ion battery's cycle capacity retention rate is lower and the storage thickness expansion rate is higher, indicating that the lithium-ion battery's cycle performance and high-temperature storage performance are poor. Therefore, by adjusting the value of A within the range of this application, the lithium-ion battery can have a higher cycle capacity retention rate and a lower storage thickness expansion rate, indicating that the lithium-ion battery has better cycle performance and high-temperature storage performance.
  • the value of B generally affects the cycling performance and high-temperature storage performance of lithium-ion batteries. As can be seen from Examples 1-4, 1-13, and 1-15, regulating the value of B within the scope of this application can result in lithium-ion batteries with lower impedance, higher cycling capacity retention, and lower storage thickness expansion, indicating that lithium-ion batteries have lower impedance, good cycling performance, and high-temperature storage performance.
  • the C/A value generally affects the cycling performance and high-temperature storage performance of lithium-ion batteries. As can be seen from Examples 1-1 to 1-33, regulating the C/A value within the scope of this application can result in lithium-ion batteries with lower impedance, higher cycle capacity retention, and lower storage thickness expansion, indicating that lithium-ion batteries have lower impedance, good cycling performance, and high-temperature storage performance.
  • first solvent generally affects the cycling performance and high-temperature storage performance of lithium-ion batteries. As can be seen from Examples 1-1, 1-27, 1-30, 1-31, and 1-33, selecting a first solvent within the scope of this application can result in lithium-ion batteries having lower impedance, higher cycling capacity retention, and lower storage thickness expansion, indicating that lithium-ion batteries have lower impedance, better cycling performance, and higher-temperature storage performance.
  • the inclusion of a first additive in the electrolyte and the value of X1 generally affect the cycling performance and high-temperature storage performance of the lithium-ion battery.
  • the lithium-ion battery can have lower impedance, higher cycle capacity retention, and lower storage thickness expansion, indicating that the lithium-ion battery has lower impedance, good cycling performance, and high-temperature storage performance.
  • A/ X1 generally affects the cycling performance and high-temperature storage performance of lithium-ion batteries. As can be seen from Examples 1-22 and 2-1 to 2-15, regulating the value of A/ X1 within the scope of this application can result in lithium-ion batteries with lower impedance, higher cycle capacity retention, and lower storage thickness expansion, indicating that lithium-ion batteries have lower impedance, good cycling performance, and high-temperature storage performance.
  • first additive typically affects the cycling performance and high-temperature storage performance of lithium-ion batteries. As can be seen from Examples 2-1, 2-3, and 2-4, selecting a first additive within the scope of this application can result in lithium-ion batteries with lower impedance, higher cycling capacity retention, and lower storage thickness expansion, demonstrating that lithium-ion batteries have lower impedance, good cycling performance, and high-temperature storage performance.
  • A/ X2 generally affects the cycling performance and high-temperature storage performance of lithium-ion batteries. As can be seen from Examples 2-11, 3-4, and 3-14, regulating the value of A/ X2 within the scope of this application can result in lithium-ion batteries with lower impedance, higher cycle capacity retention, and lower storage thickness expansion, indicating that lithium-ion batteries have lower impedance, good cycling performance, and high-temperature storage performance.
  • the type of second additive typically affects the cycling performance and high-temperature storage performance of lithium-ion batteries. As can be seen from Examples 3-4, 3-9, and 3-10, selecting a second additive within the scope of this application can result in lithium-ion batteries with lower impedance, higher cycle capacity retention, and lower storage thickness expansion, demonstrating that lithium-ion batteries have lower impedance, good cycling performance, and high-temperature storage performance.

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Abstract

本申请提供了一种电解液、包含该电解液的二次电池及电子装置。电解液包括二氟磷酸锂和第一锂盐，第一锂盐包括六氟磷酸锂或双氟磺酰亚胺锂中的至少一种；基于电解液的质量，二氟磷酸锂的质量百分含量为A％，第一锂盐的质量百分含量为B％，2≤A≤8.8，0.1≤A/B≤1；电解液还包括第一溶剂，第一溶剂的供体数为10以上，或第一溶剂的介电常数为5以上，基于电解液的质量，第一溶剂的质量百分含量为C％，5≤C≤60。电解液包括二氟磷酸锂以及上述第一锂盐和第一溶剂，并调控A、A/B和C的值在上述范围内，可以改善二次电池的循环性能和高温存储性能。

Description

一种电解液、包含该电解液的二次电池及电子装置 技术领域
本申请涉及电化学技术领域，特别是涉及一种电解液、包含该电解液的二次电池及电子装置。
背景技术
二次电池，例如锂离子电池，具有高能量密度、低维护、相对较低的自放电、长循环寿命、无记忆效应、工作电压稳定和环境友好等特性受到人们的广泛关注，被广泛用于便携式电子设备、电动工具和电动汽车等领域。然而随着技术的快速发展以及市场需求的多样性，人们对二次电池也提出了更高的要求。
在充放电过程中，电解液中的锂盐都会参与负极固态电解质界面膜(SEI膜)和正极固态电解质界面膜(CEI膜)的形成，SEI膜和CEI膜对锂离子电池的性能具有重要影响。电解液包括二氟磷酸锂有利于形成性能良好的SEI膜和CEI膜，改善锂离子电池的循环性能。但是在常用的电解液(例如碳酸酯体系电解液)中，二氟磷酸锂的溶解度非常低，仅为1％左右，这严重限制了其作用的发挥，不利于改善二次电池的循环性能。
发明内容
本申请的目的在于提供一种电解液、包含该电解液的二次电池及电子装置，以改善二次电池的循环性能。具体技术方案如下：
本申请的第一方面提供了一种电解液，其包括二氟磷酸锂和第一锂盐，第一锂盐包括六氟磷酸锂或双氟磺酰亚胺锂中的至少一种；基于电解液的质量，二氟磷酸锂的质量百分含量为A％，第一锂盐的质量百分含量为B％，2≤A≤8.8，0.1≤A/B≤1；电解液还包括第一溶剂，第一溶剂的供体数为10以上，或第一溶剂的介电常数为5以上，基于电解液的质量，第一溶剂的质量百分含量为C％，5≤C≤60。本申请提供的电解液中，二氟磷酸锂具有较高的溶解度，通过将二氟磷酸锂与第一锂盐进行合理搭配，可以发挥二者的协同作用，有利于形成稳定的SEI膜和CEI膜，同时，二氟磷酸锂在上述第一溶剂中具有较高的溶解度，可以更好地发挥二氟磷酸锂的作用，改善二次电池的循环性能和高温存储性能。从而，电解液包括二氟磷酸锂以及上述第一锂盐和第一溶剂，并调控A、A/B和C的值在上述范围内，可以改善二次电池的循环性能和高温存储性能。
在本申请的一些实施方案中，6.25≤B≤17。通过调控B的值在上述范围内，可以使得电解液具有合适的粘度的同时具有较高的电导率，提高锂离子的迁移速率，从而可以更 好的改善二次电池的循环性能。
在本申请的一些实施方案中，2.2≤A≤7，0.2≤A/B≤0.8。通过调控A、A/B的值在上述范围内，更有利于发挥二氟磷酸锂与第一锂盐之间的协同作用，有利于形成更稳定的SEI膜和CEI膜，从而进一步改善二次电池的循环性能和高温存储性能。
在本申请的一些实施方案中，3≤C/A≤25。二氟磷酸锂在上述第一溶剂中具有较高的溶解度，可以更好地发挥二氟磷酸锂的作用，另一方面由于上述第一溶剂本身的电化学窗口较窄，通过第一溶剂和二氟磷酸锂的含量的合理搭配，即调控C/A的值在上述范围内，可以减少上述第一溶剂的分解，有利于进一步改善二次电池的循环性能和高温存储性能。
在本申请的一些实施方案中，第一溶剂包括碳酸乙烯酯、乙酸乙酯、乙二醇二甲醚、磷酸三甲酯、磷酸三乙酯、磷酸三丙酯、磷酸三丁酯、环丁砜、二甲基亚砜、N,N二甲基甲酰胺、N,N二甲基乙酰胺、N-甲基乙酰胺、四甲基脲或γ-丁内酯中的至少一种。选用上述范围内的第一溶剂，有利于更好的改善二次电池的循环性能和高温存储性能。
在本申请的一些实施方案中，电解液还包括第一添加剂，第一添加剂包括1,3-丙烷磺内酯、1,3-丙烯磺酸内酯、硫酸乙烯酯、1,3-丙二醇环硫酸酯、2,4-丁烷磺内酯、1,4-丁烷磺内酯、碳酸亚乙烯酯或氟代碳酸乙烯酯中的至少一种，基于电解液的质量，第一添加剂的质量百分含量为X1％，0.05≤X1≤12。电解液包括二氟磷酸锂的基础上，进一步引入上述第一添加剂，并调控X1的值在上述范围内，可以发挥二氟磷酸锂与上述第一添加剂的协同作用，有利于增加SEI膜和CEI膜中的有机-无机杂化界面，进一步提升SEI膜和CEI膜的稳定性，从而能够进一步改善二次电池的循环性能和高温存储性能。
在本申请的一些实施方案中，0.3≤A/X1≤120。通过调控A/X1的在上述范围内，可以更好地发挥二氟磷酸锂与上述第一添加剂的协同作用，进一步增强SEI膜和CEI膜的稳定性，从而使得二次电池具有良好的循环性能和高温存储性能。
在本申请的一些实施方案中，电解液还包括第二添加剂，第二添加剂包括双草酸硼酸锂、四氟硼酸锂、二氟草酸硼酸锂、三氟甲磺酸锂、4,5-二氰基-2-三氟甲基-咪唑锂或四硼酸锂中的至少一种，基于电解液的质量，第二添加剂的质量百分含量为X2％，0.1≤X2≤2。电解液包括二氟磷酸锂的基础上，进一步引入上述第二添加剂，并调控X2的值在上述范围内，可以发挥二氟磷酸锂与上述第二添加剂的协同作用，进一步提升SEI膜和CEI膜的稳定性，减少正极极片和负极极片表面的界面副反应，从而能够进一步改善二次电池的循环性能和高温存储性能。
在本申请的一些实施方案中，2≤A/X2≤44。通过调控A/X2的在上述范围内，可以更好地发挥二氟磷酸锂与上述第二添加剂的协同作用，进一步增强SEI膜和CEI膜的稳定性， 从而使得二次电池具有良好的循环性能和高温存储性能。
本申请的第二方面提供了一种二次电池，其包括本申请第一方面提供的电解液，则本申请提供的二次电池具有良好的循环性能和高温存储性能。
本申请的第三方面提供了一种电子装置，其包括本申请第二方面提供的二次电池。本申请提供的二次电池具有良好的循环性能和高温存储性能，从而本申请的电子装置具有较长的使用寿命。
本申请的有益效果：
本申请提供了一种电解液、包含该电解液的二次电池及电子装置。电解液包括二氟磷酸锂和第一锂盐，第一锂盐包括六氟磷酸锂或双氟磺酰亚胺锂中的至少一种；基于电解液的质量，二氟磷酸锂的质量百分含量为A％，第一锂盐的质量百分含量为B％，2≤A≤8.8，0.1≤A/B≤1；电解液还包括第一溶剂，第一溶剂的供体数为10以上，或第一溶剂的介电常数为5以上，基于电解液的质量，第一溶剂的质量百分含量为C％，5≤C≤60。本申请提供的电解液中，二氟磷酸锂具有较高的溶解度，通过将二氟磷酸锂与第一锂盐进行合理搭配，可以发挥二者的协同作用，有利于形成稳定的SEI膜和CEI膜，从而改善二次电池的循环性能和高温存储性能。
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，以下举实施例，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。本领域技术人员基于本申请所获得的所有其他实施例，都属于本申请保护的范围。
需要说明的是，在以下内容中，以锂离子电池作为二次电池的例子来解释本申请，但是本申请的二次电池并不仅限于锂离子电池。
本申请的第一方面提供了一种电解液，其包括二氟磷酸锂(LiPO2F2)和第一锂盐，第一锂盐包括六氟磷酸锂(LiPF6)或双氟磺酰亚胺锂(LiFSI)中的至少一种；基于电解液的质量，二氟磷酸锂的质量百分含量为A％，第一锂盐的质量百分含量为B％，2≤A≤8.8，0.1≤A/B≤1，优选为2.2≤A≤7，0.2≤A/B≤0.8，例如A的值可以为2、2.2、2.8、3、3.5、4、4.6、5、5.7、6、6.4、7、7.5、8、8.8或为其中任意两个数值组成的范围，A/B的值可以为0.1、0.15、0.2、0.3、0.4、0.5、0.6、0.7、0.8、0.9、1或为其中任意两个数值组成的范围。电解液还包括第一溶剂，第一溶剂的供体数(DN)为10以上，或第一溶剂的介电常数(ε)为5以上，基于电解液的质量，第一溶剂的质量百分含量为C％，5≤C≤60。在一些实施方案中，第一溶剂的供体数DN可以为10至50，第一溶剂的介电常数ε可以为5至100。例如第一溶剂的供体数DN可以为10、12、14、15、16、18、20、24、25、27、 30、33、37、40、42、45、47、50或为其中任意两个数值组成的范围，第一溶剂的介电常数ε可以为5、6、7、8、9、10、12、15、17、20、30、40、50、60、70、75、80、85、90、91、95、100或为其中任意两个数值组成的范围，C的值可以为5、8、10、14、17、18、20、23、25、26、30、33、35、37、40、44、45、47、50、53、55、58、60或为其中任意两个数值组成的范围。
发明人发现，当A的值过小时，例如小于2，电解液中的二氟磷酸锂的含量过低，不利于形成稳定的SEI膜和CEI膜，从而无法改善二次电池的循环性能和高温存储性能；当A的值过大时，例如大于8.8，电解液中的二氟磷酸锂的含量过高，对于溶剂的要求过高或者二氟磷酸锂无法溶解，并且二氟磷酸锂在溶液中的解离度很低，较高浓度的二氟磷酸锂会显著提升电解液粘度而影响电解液中离子的传输，从而影响二次电池的循环性能。当A/B的值过小时，例如小于0.1，二氟磷酸锂和第一锂盐搭配不合理，不利于发挥二者之间的协同作用，在正极和负极界面上形成的SEI膜和CEI膜的稳定性较差，同时，第一锂盐解离出的锂离子会和电解液中的溶剂进行溶剂化，这样锂离子在正极和负极的迁移过程中，会使得更多的溶剂分子到达反应界面，正极和负极的界面副反应增多，从而影响二次电池的循环性能和高温存储性能；当A/B的值过大时，例如大于1，二氟磷酸锂和第一锂盐搭配不合理，不利于发挥二者之间的协同作用，过高浓度的二氟磷酸锂自身无法提供可传导的锂离子，且由于其浓度过高会导致电解液的粘度过大，锂离子的迁移受阻，会使得电解液的电导率进一步降低，从而不利于提高二次电池的循环性能。当C的值过小时，例如小于5，不利于二氟磷酸锂在电解液中的溶解，也即电解液中二氟磷酸锂的溶解度较低，无法形成稳定的SEI膜和CEI膜，从而无法改善二次电池的循环性能和高温存储性能，而对于添加较高含量的二氟磷酸锂的电解液，当第一溶剂含量过少时，二氟磷酸锂甚至可能无法完全溶解，得到的电解液无法用于二次电池；当C的值过大时，例如大于60，由于第一溶剂本身的电化学窗口较窄，其含量过高时会导致正极和负极的界面副反应增加，不利于改善二次电池的循环性能和高温存储性能。当第一溶剂的供体数和介电常数均较小时，例如DN＜10且ε＜5，二氟磷酸锂在第一溶剂的溶解度较低，不利于发挥二氟磷酸锂的作用以及二氟磷酸锂与第一锂盐的协同作用，从而不利于改善二次电池的循环性能和高温存储性能。因此，本申请提供的电解液中，二氟磷酸锂具有较高的溶解度，通过将二氟磷酸锂与第一锂盐进行合理搭配，可以发挥二者的协同作用，有利于形成稳定的SEI膜和CEI膜，同时，二氟磷酸锂在上述第一溶剂中具有较高的溶解度，可以更好地发挥二氟磷酸锂的作用，改善二次电池的循环性能和高温存储性能。从而，电解液包括二氟磷酸锂以及上述第一锂盐和第一溶剂，并调控A、A/B和C的值在上述范围内，可以改善二次电池的循环性 能和高温存储性能。
在本申请的一些实施方案中，6.25≤B≤17，例如B的值可以为6.25、8、9、10、12、14、15、16、17或为其中任意两个数值组成的范围。通过调控B的值在上述范围内，可以使得电解液具有合适的粘度的同时具有较高的电导率，提高离子的迁移速率，从而可以更好的改善二次电池的循环性能。
在本申请的一些实施方案中，3≤C/A≤25，例如C/A的值可以为3、4、5、6、8、9、10、12、14、15、17、20、21、23、25或为其中任意两个数值组成的范围。二氟磷酸锂在上述第一溶剂中具有较高的溶解度，可以更好地发挥二氟磷酸锂的作用，另一方面由于上述第一溶剂本身的电化学窗口较窄，通过第一溶剂和二氟磷酸锂的含量的合理搭配，即调控C/A的值在上述范围内，可以减少上述第一溶剂在循环过程中或者高温下的分解，有利于进一步改善二次电池的循环性能和高温存储性能。
在本申请的一些实施方案中，第一溶剂包括碳酸乙烯酯、乙酸乙酯、乙二醇二甲醚、磷酸三甲酯、磷酸三乙酯、磷酸三丙酯、磷酸三丁酯、环丁砜、二甲基亚砜、N,N二甲基甲酰胺、N,N二甲基乙酰胺、N-甲基乙酰胺、四甲基脲或γ-丁内酯中的至少一种。二氟磷酸锂在上述第一溶剂中具有较高的溶解度，可以更好地发挥二氟磷酸锂的作用，从而选用上述范围内的第一溶剂，有利于更好的改善二次电池的循环性能和高温存储性能。
在本申请的一些实施方案中，电解液还包括第一添加剂，第一添加剂包括1,3-丙烷磺内酯(1,3-PS)、1,3-丙烯磺酸内酯、硫酸乙烯酯(VC)、1,3-丙二醇环硫酸酯、2,4-丁烷磺内酯(2,4-BS)、1,4-丁烷磺内酯(1,4-BS)、碳酸亚乙烯酯或氟代碳酸乙烯酯(FEC)中的至少一种，基于电解液的质量，第一添加剂的质量百分含量为X1％，0.05≤X1≤12，例如X1的值可以为0.05、0.1、0.3、0.8、1、3、5、6、8、10、12或为其中任意两个数值组成的范围。电解液包括二氟磷酸锂的基础上，进一步引入上述第一添加剂，并调控X1的值在上述范围内，可以发挥二氟磷酸锂与上述第一添加剂的协同作用，可以在正极和负极表面生成有机的含氟磷酸盐(例如LixPFy、LixPFyOz)以及无机的LiF等组分，有利于增加SEI膜和CEI膜中的有机-无机杂化界面，进一步增强SEI膜和CEI膜的稳定性，从而能够进一步改善二次电池的循环性能和高温存储性能。
在本申请的一些实施方案中，0.3≤A/X1≤120，例如A/X1的值可以为0.3、0.5、0.8、1、1.25、1.5、3、5、8、10、12、20、40、50、75、90、100、105、120或为其中任意两个数值组成的范围。通过调控A/X1的在上述范围内，可以更好地发挥二氟磷酸锂与上述第一添加剂的协同作用，进一步增强SEI膜和CEI膜的稳定性，从而使得二次电池具有良好的循环性能和高温存储性能。
在本申请的一些实施方案中，电解液还包括第二添加剂，第二添加剂包括双草酸硼酸锂(LiBOB)、四氟硼酸锂(LiBF4)、二氟草酸硼酸锂(LiDFOB)、三氟甲磺酸锂(LiCF3SO3)、4,5-二氰基-2-三氟甲基-咪唑锂(LITDI)或四硼酸锂(Li2B4O7)中的至少一种，基于电解液的质量，第二添加剂的质量百分含量为X2％，0.1≤X2≤2，例如X2的值可以为0.1、0.3、0.5、0.8、1、1.2、1.4、1.5、1.6、1.8、2或为其中任意两个数值组成的范围。电解液包括二氟磷酸锂的基础上，进一步引入上述第二添加剂，并调控X2的值在上述范围内，可以发挥二氟磷酸锂与上述第二添加剂的协同作用，进一步增强SEI膜和CEI膜的稳定性，减少正极极片和负极极片表面的界面副反应，从而能够进一步改善二次电池的循环性能和高温存储性能。
在本申请的一些实施方案中，2≤A/X2≤44，例如A/X2的值可以为2、3、5、8、10、12、18、20、24、25、28、30、33、35、37、40、44或为其中任意两个数值组成的范围。通过调控A/X2的在上述范围内，可以更好地发挥二氟磷酸锂与上述第二添加剂的协同作用，进一步增强SEI膜和CEI膜的稳定性，从而使得二次电池具有良好的循环性能和高温存储性能。
本申请的电解液还可以包括第二溶剂。本申请对上述第二溶剂的种类没有特别限制，只要能实现本申请的目的即可，例如可以包括但不限于碳酸二甲酯、碳酸二乙酯(DEC)、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯或碳酸甲乙酯中的至少一种。本申请对第二溶剂的质量百分含量没有特别限制，只要能实现本申请的目的即可，例如基于电解液的质量，第二溶剂的质量百分含量可以为0.2％至86.75％。例如第二溶剂的质量百分含量可以为0.2％、2.2％、5％、8％、10％、12.2％、14.2％、17％、20％、23％、26％、30％、33％、35％、37％、40％、43％、45％、47％、50％、53％、55％、58％、60％、62％、66％、69％、70％、72％、75％、78％、80％、82％、83％、85％、86.6％、86.75％或为其中任意两个数值组成的范围。
在一些实施方案中，电解液包括二氟磷酸锂、第一锂盐、第一溶剂和第二溶剂，二氟磷酸锂、第一锂盐、第一溶剂的质量百分含量如上所述，第二溶剂的质量百分含量为14.2％至86.75％。将具有上述特征的电解液应用于二次电池，可以改善二次电池的循环性能和高温存储性能。
在一些实施方案中，电解液包括二氟磷酸锂、第一锂盐、第一溶剂、第一添加剂和第二溶剂，二氟磷酸锂、第一锂盐、第一溶剂、第一添加剂的质量百分含量如上所述，第二溶剂的质量百分含量为2.2％至86.7％。将具有上述特征的电解液应用于二次电池，有利于进一步改善二次电池的循环性能和高温存储性能。
在一些实施方案中，电解液包括二氟磷酸锂、第一锂盐、第一溶剂、第二添加剂和第 二溶剂，二氟磷酸锂、第一锂盐、第一溶剂、第二添加剂的质量百分含量如上所述，第二溶剂的质量百分含量为12.2％至86.65％。将具有上述特征的电解液应用于二次电池，有利于进一步改善二次电池的循环性能和高温存储性能。
在一些实施方案中，电解液包括二氟磷酸锂、第一锂盐、第一溶剂、第一添加剂、第二添加剂和第二溶剂，二氟磷酸锂、第一锂盐、第一溶剂、第一添加剂、第二添加剂的质量百分含量如上所述，第二溶剂的质量百分含量为0.2％至86.6％。将具有上述特征的电解液应用于二次电池，有利于进一步改善二次电池的循环性能和高温存储性能。
本申请的第二方面提供了一种二次电池，其包括本申请第一方面提供的电解液，则本申请提供的二次电池具有良好的循环性能和高温存储性能。
本申请的二次电池还包括正极极片。本申请对正极极片没有特别限制，只要能够实现本申请目的即可。例如，正极极片包含正极集流体和设置在正极集流体至少一个表面上的正极材料层。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”可以是正极集流体表面的全部区域，也可以是正极集流体表面的部分区域，本申请没有特别限制，只要能实现本申请目的即可。
本申请的二次电池还包括负极极片，本申请对负极极片没有特别限制，只要能够实现本申请目的即可。例如，负极极片包含负极集流体和设置在负极集流体至少一个表面上的负极材料层。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。本申请的负极材料层包含负极活性材料。本申请对负极活性材料的种类没有特别限制，只要能够实现本申请目的即可。例如，负极活性材料可以包含天然石墨、人造石墨、中间相微碳球(MCMB)、硬碳、软碳、硅、硅-碳复合物、SiOx(0＜x≤2)、Li-Sn合金、Li-Sn-O合金、Sn、SnO、SnO2、尖晶石结构的钛酸锂Li4Ti5O12、Li-Al合金或金属锂中的至少一种。在本申请中，对负极集流体和负极材料层的厚度没有特别限制，只要能够实现本申请目的即可。例如，负极集流体的厚度为4μm至12μm，单面负极材料层的厚度为30μm至160μm。本申请对负极材料层中负极活性材料、负极导电剂和负极粘结剂的质量比没有特别限制，只要能够实现本申请目的即可。
本申请的负极材料层还可以包含负极导电剂、负极粘结剂和负极分散剂。本申请对负极导电剂和负极粘结剂没有特别限制，只要能够实现本申请目的即可。例如，负极导电剂可以包括但不限于导电炭黑(Super P)、碳纳米管(CNTs)、石墨、碳纤维、碳纳米线、 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。负极粘结剂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、羧甲基纤维素锂、聚酰胺酰亚胺、丁苯橡胶或聚偏氟乙烯(PVDF)中的至少一种。负极分散剂可以包括羧甲基纤维素钠。
本申请中，对负极极片的制备方法没有特别限制，只要能实现本申请的目的即可，例如可以通过以下方法制备：将负极活性材料、负极粘结剂、负极分散剂混合，加入去离子水搅拌均匀，获得固含量为50wt％至75wt％的负极浆料。将负极浆料均匀涂覆于负极集流体的一个表面上，烘干后得到单面涂覆负极材料层的负极极片。然后在负极集流体的另一个表面上重复以上涂布步骤，烘干后得到双面涂布负极材料层的负极极片，涂布完成后，经冷压、裁切得到负极极片。
本申请对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，正极集流体可以包含铝箔、铝合金箔或复合集流体(例如铝碳复合集流体)等。本申请对正极集流体和正极材料层的厚度没有特别限制，只要能够实现本申请目的即可。例如，正极集流体的厚度为5μm至20μm，单面正极材料层的厚度为30μm至120μm。在本申请中，正极材料层包括正极活性材料，本申请对正极活性材料的种类没有特别限制，只要能够实现本申请目的即可。正极活性材料包括可逆地嵌入和脱嵌锂离子的化合物。在一些实施方案中，正极材料层包括相对于金属锂为4.5V以上的工作电位的正极活性材料。即本申请的正极活性材料可以在高压下工作。在一些实施方案中，正极活性材料可以包括镍钴锰酸锂(NCM)、镍钴铝酸锂、磷酸铁锂、富锂锰基材料、钴酸锂、锰酸锂或磷酸锰铁锂等中的至少一种。镍钴锰酸锂可以包括但不限于LiNi0.8Co0.1Mn0.1O2(NCM811)、LiNi0.6Co0.2Mn0.2O2(NCM622)、LiNi0.5Co0.2Mn0.3O2(NCM523)、LiNi1/3Co1/3Mn1/3O2(NCM333)或LiNi0.9Co0.05Mn0.05O2(NCM955)中的至少一种。上述正极活性材料可以经过掺杂处理。在一些实施方案中，用于掺杂的元素可以包括K、Na、Ca、Mg、B、Al、Co、Si、V、Ga、Sn或Zr中的至少一种。本申请的正极材料层还可以包含正极导电剂和正极粘结剂。本申请对正极导电剂和正极粘结剂没有特别限制，只要能够实现本申请目的即可。例如，正极导电剂可以与上述负极导电剂相同，正极粘结剂可以与上述负极粘结剂相同。本申请对正极材料层中正极活性材料、正极导电剂和正极粘结剂的质量比没有特别限制，只要能够实 现本申请目的即可。
本申请中，对正极极片的制备方法没有特别限制，只要能实现本申请的目的即可，例如可以通过以下方法制备：将正极活性材料、正极导电剂、正极粘结剂混合，加入N-甲基吡咯烷酮(NMP)搅拌均匀，获得固含量为65wt％至85wt％的正极浆料。将正极浆料均匀涂覆于正极集流体的一个表面上，烘干后得到单面涂覆正极材料层的正极极片。然后在正极集流体的另一个表面上重复以上涂布步骤，烘干后得到双面涂布正极材料层的正极极片，涂布完成后，经冷压、裁切得到正极极片。
本申请的二次电池还包括隔离膜。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，例如隔离膜的材料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)类隔离膜、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)、氨纶或芳纶膜等中的至少一种。隔离膜的类型可以包括但不限于织造膜、非织造膜(无纺布)、微孔膜、复合膜、碾压膜或纺丝膜等中的至少一种。本申请的隔离膜可以具有多孔结构，多孔层设置在隔离膜的至少一个表面上，多孔层包括无机颗粒和粘结剂，无机颗粒可以包括氧化铝、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。粘结剂可以包括聚偏氟乙烯、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、羧甲基纤维素纳、聚乙烯吡咯烷酮、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。本申请对多孔结构的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，例如隔离膜的厚度可以为5μm至50μm。
本申请对二次电池的种类没有特别限制，其可以包括发生电化学反应的任何装置。例如，二次电池可以包括但不限于：锂金属二次电池、锂离子电池、钠离子电池、锂聚合物二次电池、锂离子聚合物二次电池。本申请对二次电池的形状没有特别限制，只要能够实现本申请目的即可。本申请的二次电池还包括包装袋，本申请对包装袋没有特别限制，只要能够实现本申请目的即可。例如可以采用铝塑膜包装袋。
二次电池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，焊接极耳后，并根据需要将其进行卷绕、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，得到二次电池；或者，将正极极片、隔离膜和负极极片按顺序堆叠，焊接极耳后，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，得到二次电池。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，从而防止二次电池内部的压力上升、过充放电。
本申请的第三方面提供了一种电子装置，其包括本申请第二方面提供的二次电池。本申请提供的二次电池具有良好的循环性能和高温存储性能，从而本申请的电子装置具有较长的使用寿命。
本申请对电子装置的种类没有特别限定，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。
实施例
以下，举出实施例及对比例来对本申请的实施方式进行更具体地说明。各种的试验及评价按照下述的方法进行。另外，只要无特别说明，“份”、“％”为质量基准。
测试方法和设备：
电解液中各成分含量的测试：
将锂离子电池以1C恒定电流放电至2.5V后拆解，收集电解液，并将拆出的正极极片、负极极片、隔离膜进行离心，将离心后得到的液体和上述电解液混合均匀，然后采用气相色谱-质谱联用仪(仪器型号为Agilent 8890)和离子色谱(仪器型号为AQUION离子色谱)进行测试，得到电解液中的各个组分并测试其含量。
循环性能测试：
通过锂离子电池的容量保持率评价锂离子电池在高电压条件下的循环性能。容量保持率越高，说明锂离子电池的循环性能越好。测试过程为：将锂离子电池置于25℃恒温箱中，静置5min，然后将锂离子电池以1C恒流充电至电压为4.28V，然后以4.28V恒压充电至电流为0.05C，再以1C恒流放电至2.5V，此为一个充放电循环。记录首次放电容量为Q1，反复进行充放电循环800次，停止测试，记录第800次的放电容量为Q2，则锂离子电池的25℃循环容量保持率(％)＝Q2/Q1×100％。
高温存储性能测试：
通过锂离子电池在60℃存储厚度膨胀率来评价锂离子电池的高温存储性能。厚度膨胀 率越小，说明锂离子电池的高温存储性能越好。测试过程如下：在25℃环境中，将锂离子电池以0.5C恒流充电至4.28V，再以4.28V恒压充电至电流为0.05C，测试锂离子电池的厚度为D1，然后将锂离子电池静置在60℃烘箱中，存储180天后取出，测试此时锂离子电池的厚度为D2。锂离子电池60℃存储厚度膨胀率＝(D2-D1)/D1×100％。
50％荷电状态(SOC)直流阻抗(DCR)测试：
在25℃环境下，将锂离子电池以0.5C的电流放电至2.5V，静置5分钟，然后以0.5C的电流充电至4.28V，再在4.28V下恒压至0.025C。静置5分钟，使用0.1C的电流放电至2.5V，标记此时的放电容量记为C1。使用0.5C1的容量充电至4.28V，在4.28V电压下恒压至0.025C1，静置5分钟，使用0.1C1的电流放电5小时，此时锂离子电池的电压记为V1，之后采用1C的电流放电1秒，此时锂离子电池的电压记为V2。50％ SOC DCR＝(V1-V2)/(1C-0.1C1)。
实施例1-1
<电解液的制备>
在含水量<10ppm的氩气气氛手套箱中，将第一溶剂乙酸乙酯和第二溶剂碳酸二乙酯混合均匀得到有机溶剂，然后向有机溶剂中依次加入二氟磷酸锂、第一锂盐六氟磷酸锂(LiPF6)溶解并混合均匀，得到电解液。其中，基于所述电解液的质量，二氟磷酸锂的质量百分含量A％、第一锂盐的质量百分含量B％、第一溶剂的质量百分含量C％如表1所示，余量为第二溶剂碳酸二乙酯。
<正极极片的制备>
将正极活性材料LiCoO2、正极导电剂导电炭黑、正极粘结剂聚偏氟乙烯按照质量比为97:1.4:1.6进行混合，加入N-甲基吡咯烷酮搅拌均匀，得到固含量为72wt％的正极浆料。将正极浆料均匀涂覆于厚度为10μm的正极集流体铝箔的一个表面上，将铝箔在85℃下烘干处理4h，得到单面涂覆正极材料层的正极极片。在铝箔的另一个表面上重复以上步骤，即得到双面涂覆正极材料层的正极极片。然后在85℃的真空条件下干燥4h后，经过冷压、裁片、分切得到规格为74mm×867mm的正极极片。其中，正极材料层的压实密度为4.15g/cm3，单面正极材料层的厚度为60μm。
<负极极片的制备>
将负极活性材料石墨、负极粘结剂丁苯橡胶、负极增稠剂羧甲基纤维素钠、按照质量比为97.4:1.4:1.2进行混合，加入去离子水搅拌均匀，获得固含量为54wt％的负极浆料。将负极浆料均匀涂覆于厚度为6μm的负极集流体铜箔的一个表面上，将铜箔在85℃下烘干处理4h，得到单面涂覆负极材料层的负极极片。在铜箔的另一个表面上重复以上步骤，即 得到双面涂覆负极材料层的负极极片。然后在85℃的真空条件下干燥4h后，经过冷压、裁片、分切得到规格为78mm×875mm的负极极片。其中，正极材料层的压实密度为1.75g/cm3，单面正极材料层的厚度为70μm。
<隔离膜的制备>
将PVDF和氧化铝陶瓷按照质量比9:1进行混合，加入去离子水作为溶剂，调配成固含量25wt％的陶瓷层浆料，并搅拌均匀，将浆料均匀的涂覆在厚度为16μm的基材聚乙烯多孔薄膜的一个表面，烘干后得到单面涂覆2μm氧化铝陶瓷层的隔离膜。之后，在该基材的另一个表面上重复以上涂覆步骤，得到双面涂覆2μm氧化铝陶瓷层的隔离膜。
<锂离子电池的制备>
将制备的正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正极极片和负极极片中间起到隔离的作用，然后卷绕得到电极组件。焊接极耳后将电极组件装入铝塑膜包装袋中，放置在85℃真空烘箱中干燥12h脱去水分，注入上述配好的电解液，经过真空封装、静置、化成(0.02C恒流充电至3.5V，再以0.1C恒流充电至3.9V)、整形、容量测试、二次封装等工序，得到锂离子电池。
实施例1-2至实施例1-33
除了按照表1调整参数以外，其余与实施例1-1相同。当二氟磷酸锂的质量百分含量A％、第一锂盐的质量百分含量B％或第一溶剂的质量百分含量C％按照表1变化时，第二溶剂的质量百分含量随之改变。
实施例2-1至实施例2-15
除了在电解液中引入第一添加剂并按照表2调整相关参数以外，其余与实施例1-22相同。当二氟磷酸锂的质量百分含量A％、第一锂盐的质量百分含量B％、第一溶剂的质量百分含量C％或第一添加剂的质量百分含量X1％按照表2变化时，第二溶剂的质量百分含量随之改变。
实施例3-1至实施例3-3
除了在电解液中引入第二添加剂并按照表3调整相关参数以外，其余与实施例1-22相同。当第二添加剂的质量百分含量X2％按照表3变化时，二氟磷酸锂的质量百分含量A％、第一溶剂的质量百分含量C％和第一锂盐的质量百分含量B％保持不变，第二溶剂的质量百分含量随之改变。
实施例3-4至实施例3-14
除了在电解液中引入第二添加剂并按照表3调整相关参数以外，其余与实施例2-11相同。当二氟磷酸锂的质量百分含量A％或第二添加剂的质量百分含量X2％按照表3变化时， 第一溶剂的质量百分含量C％和第一锂盐的质量百分含量B％保持不变，第二溶剂的质量百分含量随之改变。
对比例1至对比例8
除了按照表1调整参数以外，其余与实施例1-1相同。当二氟磷酸锂的质量百分含量A％、第一锂盐的质量百分含量B％或第一溶剂的质量百分含量C％按照表1变化时，第二溶剂的质量百分含量随之改变。
各实施例和对比例的制备参数及性能参数如表1至表3所示。
表1


注：表1中“-”表示锂离子电池的性能数据无法测得。
从实施例1-1至实施例1-33、对比例1至对比例8可以看出，电解液包括二氟磷酸锂以及本申请的第一锂盐和第一溶剂，并调控A、A/B和C的值在本申请范围内，可以使得锂离子电池具有较低的阻抗、更高的循环容量保持率以及更低的存储厚度膨胀率，说明锂离子电池具有较低的阻抗、更好的循环性能和高温存储性能。对比例1至对比例7的锂离子电池，A、A/B或C中的至少一者未在本申请范围内，对比例8的锂离子电池中，采用苯乙醚作为溶剂替换第一溶剂乙酸乙酯，对比例1至对比例6的锂离子电池的循环容量保持率更低、存储厚度膨胀率更高，说明锂离子电池的循环性能和高温存储性能较差。对比例7和对比例8中，二氟磷酸锂不完全溶解，无法测得锂离子电池的性能数据。
从实施例1-1至实施例1-7、对比例1和对比例2可以看出，当A的值过小时，例如对比例1，锂离子电池的循环容量保持率更低、存储厚度膨胀率更高；当A的值过大时，例如对比例2，锂离子电池的循环容量保持率更低、存储厚度膨胀率更高，说明锂离子电池的循环性能和高温存储性能较差。从而，调控A的值在本申请范围内，可以使得锂离子电池具有更高的循环容量保持率以及更低的存储厚度膨胀率，说明锂离子电池具有更好的循环性能和高温存储性能。
从实施例1-1至实施例1-15、对比例3至对比例5可以看出，当A/B的值过小时，例如对比例3，锂离子电池的循环容量保持率更低、存储厚度膨胀率更高；当A/B的值过大时，例如对比例4和对比例5，锂离子电池的循环容量保持率更低、存储厚度膨胀率更高，说明锂离子电池的循环性能和高温存储性能较差。从而，调控A/B的值在本申请范围内，可以使得锂离子电池具有更高的循环容量保持率以及更低的存储厚度膨胀率，说明锂离子电池具有更好的循环性能和高温存储性能。
从实施例1-3、实施例1-20至实施例1-23、对比例6至对比例7可以看出，当C的值过小时，例如对比例7，二氟磷酸锂不完全溶解，无法测得锂离子电池的性能数据；当C的值过大时，例如对比例6，锂离子电池的循环容量保持率更低、存储厚度膨胀率更高，说明锂离子电池的循环性能和高温存储性能较差。从而，调控C的值在本申请范围内，可以使得锂离子电池具有更高的循环容量保持率以及更低的存储厚度膨胀率，说明锂离子电池具有更好的循环性能和高温存储性能。
从实施例1-1、实施例1-27、实施例1-30、实施例1-31至实施例1-33和对比例8可以看出，第一溶剂的供体数和介电常数未在本申请范围内时，二氟磷酸锂不完全溶解，无法测得锂离子电池的性能数据。而选用供体数或介电常数在本申请范围内的第一溶剂，可以使得锂离子电池具有更高的循环容量保持率以及更低的存储厚度膨胀率，说明锂离子电池具有更好的循环性能和高温存储性能。
B的值通常会影响锂离子电池的循环性能和高温存储性能。从实施例1-4、实施例1-13至实施例1-15可以看出，调控B的值在本申请范围内，可以使得锂离子电池具有较低的阻抗、较高的循环容量保持率以及较低的存储厚度膨胀率，说明锂离子电池具有较低的阻抗、良好的循环性能和高温存储性能。
C/A的值通常会影响锂离子电池的循环性能和高温存储性能。从实施例1-1至实施例1-33可以看出，调控C/A的值在本申请范围内，可以使得锂离子电池具有较低的阻抗、较高的循环容量保持率以及较低的存储厚度膨胀率，说明锂离子电池具有较低的阻抗、良好的循环性能和高温存储性能。
第一溶剂的种类通常会影响锂离子电池的循环性能和高温存储性能。从实施例1-1、实施例1-27、实施例1-30、实施例1-31至实施例1-33可以看出，选用本申请范围内的第一溶剂，可以使得锂离子电池具有较低的阻抗、较高的循环容量保持率以及较低的存储厚度膨胀率，说明锂离子电池具有较低的阻抗、良好的循环性能和高温存储性能。
表2

注：表2中，“/”表示无相关参数或不存在对应的物质，“FEC+1,3-PS”的质量百分含量为“2.5+0.5”表示FEC的质量百分含量为2.5％，1,3-PS的质量百分含量为0.5％，二者之和为X1％，其余类似表述以此类推。
电解液包括第一添加剂以及X1的值通常会影响锂离子电池的循环性能和高温存储性能。从实施例1-22、实施例2-1至实施例2-9可以看出，电解液包括二氟磷酸锂以及本申请的第一锂盐和第一溶剂的基础上，进一步引入第一添加剂，并调控X1的值在本申请范围内，可以使得锂离子电池具有较低的阻抗、较高的循环容量保持率以及较低的存储厚度膨胀率，说明锂离子电池具有较低的阻抗、良好的循环性能和高温存储性能。
A/X1的值通常会影响锂离子电池的循环性能和高温存储性能。从实施例1-22、实施例2-1至实施例2-15可以看出，调控A/X1的值在本申请范围内，可以使得锂离子电池具有较低的阻抗、较高的循环容量保持率以及较低的存储厚度膨胀率，说明锂离子电池具有较低的阻抗、良好的循环性能和高温存储性能。
第一添加剂的种类通常会影响锂离子电池的循环性能和高温存储性能。从实施例2-1、实施例2-3至实施例2-4可以看出，选用本申请范围内的第一添加剂，可以使得锂离子电池具有较低的阻抗、较高的循环容量保持率以及较低的存储厚度膨胀率，说明锂离子电池具有较低的阻抗、良好的循环性能和高温存储性能。
表3

注：表3中，“/”表示无相关参数或不存在对应的物质，“LiBF4+LiDFOB+LiBOB”的质量百分含量为“0.2+0.2+0.2”表示LiBF4的质量百分含量为0.2％，LiDFOB的质量百分含量为0.2％，LiBOB的质量百分含量为0.2％，三者之和为X2％，其余类似表述以此类推。
电解液包括第二添加剂以及X2的值通常会影响锂离子电池的循环性能和高温存储性能。从实施例1-22、实施例3-1至实施例3-3可以看出，电解液包括二氟磷酸锂以及本申请的第一锂盐和第一溶剂的基础上，进一步引入第二添加剂，并调控X2的值在本申请范围内，可以使得锂离子电池具有较低的阻抗、较高的循环容量保持率以及较低的存储厚度膨胀率，说明锂离子电池具有较低的阻抗、良好的循环性能和高温存储性能。从实施例2-11、实施例3-4至实施例3-11可以看出，电解液包括二氟磷酸锂以及本申请的第一锂盐、第一溶剂和第一添加剂的基础上，进一步引入第二添加剂，并调控X2的值在本申请范围内，可以使得锂离子电池具有较低的阻抗、较高的循环容量保持率以及较低的存储厚度膨胀率，说明锂离子电池具有较低的阻抗、良好的循环性能和高温存储性能。
A/X2的值通常会影响锂离子电池的循环性能和高温存储性能。从实施例2-11、实施例3-4至实施例3-14可以看出，调控A/X2的值在本申请范围内，可以使得锂离子电池具有较低的阻抗、较高的循环容量保持率以及较低的存储厚度膨胀率，说明锂离子电池具有较低的阻抗、良好的循环性能和高温存储性能。
第二添加剂的种类通常会影响锂离子电池的循环性能和高温存储性能。从实施例3-4、实施例3-9至实施例3-10可以看出，选用本申请范围内的第二添加剂，可以使得锂离子电池具有较低的阻抗、较高的循环容量保持率以及较低的存储厚度膨胀率，说明锂离子电池具有较低的阻抗、良好的循环性能和高温存储性能。
以上所述仅为本申请的较佳实施例，并不用以限制本申请，凡在本申请的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本申请保护的范围之内。

Claims (11)

  1. 一种电解液，其包括二氟磷酸锂和第一锂盐，所述第一锂盐包括六氟磷酸锂或双氟磺酰亚胺锂中的至少一种；基于所述电解液的质量，二氟磷酸锂的质量百分含量为A％，所述第一锂盐的质量百分含量为B％，2≤A≤8.8，0.1≤A/B≤1；
    所述电解液还包括第一溶剂，所述第一溶剂的供体数为10以上，或所述第一溶剂的介电常数为5以上，基于所述电解液的质量，所述第一溶剂的质量百分含量为C％，5≤C≤60。
  2. 根据权利要求1所述的电解液，其中，6.25≤B≤17。
  3. 根据权利要求1所述的电解液，其中，2.2≤A≤7，0.2≤A/B≤0.8。
  4. 根据权利要求1所述的电解液，其中，3≤C/A≤25。
  5. 根据权利要求1所述的电解液，其中，所述第一溶剂包括碳酸乙烯酯、乙酸乙酯、乙二醇二甲醚、磷酸三甲酯、磷酸三乙酯、磷酸三丙酯、磷酸三丁酯、环丁砜、二甲基亚砜、N,N二甲基甲酰胺、N,N二甲基乙酰胺、N-甲基乙酰胺、四甲基脲或γ-丁内酯中的至少一种。
  6. 根据权利要求1至5中任一项所述的电解液，其中，所述电解液还包括第一添加剂，所述第一添加剂包括1,3-丙烷磺内酯、1,3-丙烯磺酸内酯、硫酸乙烯酯、1,3-丙二醇环硫酸酯、2,4-丁烷磺内酯、1,4-丁烷磺内酯、碳酸亚乙烯酯或氟代碳酸乙烯酯中的至少一种，
    基于所述电解液的质量，所述第一添加剂的质量百分含量为X1％，0.05≤X1≤12。
  7. 根据权利要求6所述的电解液，其中，0.3≤A/X1≤120。
  8. 根据权利要求1至5中任一项所述的电解液，其中，所述电解液还包括第二添加剂，所述第二添加剂包括双草酸硼酸锂、四氟硼酸锂、二氟草酸硼酸锂、三氟甲磺酸锂、4,5-二氰基-2-三氟甲基-咪唑锂或四硼酸锂中的至少一种，
    基于所述电解液的质量，所述第二添加剂的质量百分含量为X2％，0.1≤X2≤2。
  9. 根据权利要求8所述的电解液，其中，2≤A/X2≤44。
  10. 一种二次电池，其包括权利要求1至9中任一项所述的电解液。
  11. 一种电子装置，其包括权利要求10所述的二次电池。
PCT/CN2024/083607 2024-03-25 2024-03-25 一种电解液、包含该电解液的二次电池及电子装置 Pending WO2025199692A1 (zh)

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CN107369849A (zh) * 2017-08-04 2017-11-21 广州天赐高新材料股份有限公司 一种锂二次电池电解液和锂二次电池
WO2017217408A1 (ja) * 2016-06-13 2017-12-21 日本電気株式会社 リチウムイオン二次電池
CN108767316A (zh) * 2018-05-16 2018-11-06 东莞市杉杉电池材料有限公司 一种三元材料体系锂离子电池电解液及锂离子电池
CN112349957A (zh) * 2019-08-06 2021-02-09 珠海冠宇电池股份有限公司 一种电解液及其制备方法和锂离子电池
CN115763983A (zh) * 2022-11-16 2023-03-07 青海民族大学 一种低温锂离子电池电解液

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Publication number Priority date Publication date Assignee Title
WO2017217408A1 (ja) * 2016-06-13 2017-12-21 日本電気株式会社 リチウムイオン二次電池
CN107369849A (zh) * 2017-08-04 2017-11-21 广州天赐高新材料股份有限公司 一种锂二次电池电解液和锂二次电池
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