CN116404258B - Secondary battery and device - Google Patents

Secondary battery and device Download PDF

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Publication number
CN116404258B
CN116404258B CN202310678982.9A CN202310678982A CN116404258B CN 116404258 B CN116404258 B CN 116404258B CN 202310678982 A CN202310678982 A CN 202310678982A CN 116404258 B CN116404258 B CN 116404258B
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secondary battery
alkyl
active material
nitrogen
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CN116404258A (en
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李思远
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Weilai Battery Technology Anhui Co ltd
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Weilai Battery Technology Anhui Co ltd
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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
    • 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
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • 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

Abstract

The present application relates to a secondary battery and an apparatus. The secondary battery of the present application comprises a positive electrode, a negative electrode, and an electrolyte, wherein the electrolyte comprises a sulfur-containing additive and a nitrogen-containing additive; the anode and the cathode comprise an active material layer and a solid electrolyte interface film positioned on the surface of the active material layer, wherein the mass percentage of sulfur element in the anode and the cathode solid electrolyte interface film is S respectively 1 % and S 2 The mass percentage of nitrogen element is N respectively 1 % and N 2 In which, S is 1.ltoreq.S 1 /S 2 +N 1 /N 2 And is less than or equal to 2. The secondary battery of the application controls the content of sulfur element and nitrogen element in the negative electrode SEI film and the proportion of the content of sulfur element and nitrogen element in the positive electrode CEI film, thereby improving the first coulombic efficiency, the normal temperature and high temperature cycle performance and the high temperature storage performance of the secondary battery.

Description

Secondary battery and device
Technical Field
The application relates to the field of energy storage. In particular, the present application relates to a secondary battery and an apparatus.
Background
The lithium ion battery rapidly occupies the 3C fields of mobile phones, notebook computers and the like by virtue of numerous advantages, and even becomes a key component of various electric automobiles. In order to further meet the demands of people for higher performance of batteries, development of lithium ion batteries with low price, high energy density, high safety and long service life is pursued by many developers.
However, in the battery cycle process, the positive and negative electrodes of the battery are easy to react with the electrolyte, so that on one hand, the capacity of the battery is reduced, the cycle life is greatly reduced, and on the other hand, the gas is generated, the volume of the battery is expanded, and the safety of the battery is reduced. As the battery operating temperature increases, the side reactions become more severe and the problem of gas production becomes more serious.
Disclosure of Invention
The application provides a secondary battery and a related device aiming at the problems of the current lithium ion battery. The secondary battery of the application improves the first coulombic efficiency, the normal temperature and high temperature cycle performance and the high temperature storage performance of the secondary battery by controlling the content of sulfur element and the content of nitrogen element in the solid electrolyte interface film (SEI film) formed on the surface of the anode active material layer and the proportion of the content of sulfur element and the content of nitrogen element in the solid electrolyte interface film (CEI film) formed on the surface of the cathode active material layer.
A first aspect of the present application provides a secondary battery comprising a positive electrode, a negative electrode, and an electrolyte, wherein the electrolyte comprises a sulfur-containing additive and a nitrogen-containing additive; the anode comprises an anode active material layer and a solid electrolyte interface film positioned on the surface of the anode active material layer, wherein the solid electrolyte interface film on the surface of the anode active material layer is tested by adopting an X-ray photoelectron spectrometer, and the mass percentage of sulfur element in the solid electrolyte interface film on the surface of the anode active material layer is S 1 The mass percent of nitrogen element is N 1 The positive electrode comprises a positive electrode active material layer and a solid electrolyte interface film positioned on the surface of the positive electrode active material layer, wherein the solid electrolyte interface film on the surface of the positive electrode active material layer contains S in percentage by mass as tested by an X-ray photoelectron spectrometer 2 The mass percent of nitrogen element is N 2 In which, S is 1.ltoreq.S 1 /S 2 +N 1 /N 2 ≤2。
A second aspect of the present application provides an apparatus comprising the secondary battery according to the first aspect.
The beneficial effects of the application are as follows:
the secondary battery optimizes the composition and structure of the anode and cathode interface films by controlling the sulfur element content and the nitrogen element content in the anode SEI film and the ratio of the sulfur element content and the nitrogen element content in the cathode CEI film, obtains a compact, stable and high-ion conductive interface film, improves the first coulombic efficiency of the secondary battery, simultaneously effectively inhibits the continuous side reaction of electrolyte, anode active material and cathode active material, reduces the consumption rate of the electrolyte, and further improves the normal temperature cycle performance, high temperature cycle performance and high temperature storage performance of the secondary battery.
Detailed Description
For simplicity, the present application discloses only a few numerical ranges specifically. However, any lower limit may be combined with any upper limit to form a range not explicitly recited; and any lower limit may be combined with any other lower limit to form a range not explicitly recited, and any upper limit may be combined with any other upper limit to form a range not explicitly recited. Furthermore, each separately disclosed point or individual value may itself be combined as a lower limit or upper limit with any other point or individual value or with other lower limit or upper limit to form a range not explicitly recited.
Unless otherwise indicated, terms used in the present application have well-known meanings commonly understood by those skilled in the art. Unless otherwise indicated, the numerical values of the parameters set forth in the present application may be measured by various measurement methods commonly used in the art (e.g., may be tested according to the methods set forth in the examples of the present application).
The list of items to which the term "at least one of" or other similar terms is attached may mean any combination of the listed items. For example, if items a and B are listed, the phrase "at least one of a and B" means only a; only B; or A and B. In another example, if items A, B and C are listed, then the phrase "at least one of A, B and C" means only a; or only B; only C; a and B (excluding C); a and C (excluding B); b and C (excluding A); or A, B and C. Item a may comprise a single component or multiple components. Item B may comprise a single component or multiple components. Item C may comprise a single component or multiple components.
The application is further described below in conjunction with the detailed description. It should be understood that the detailed description is intended by way of illustration only and is not intended to limit the scope of the application.
1. Secondary battery
The secondary battery provided by the application comprises a positive electrode, a negative electrode and an electrolyte, wherein the electrolyte comprises a sulfur-containing additive and a nitrogen-containing additive; the anode comprises an anode active material layer and a solid electrolyte interface film positioned on the surface of the anode active material layer, wherein the solid electrolyte interface film on the surface of the anode active material layer contains sulfur element by adopting an X-ray photoelectron spectrometerIs S in mass percent 1 The mass percent of nitrogen element is N 1 The positive electrode comprises a positive electrode active material layer and a solid electrolyte interface film positioned on the surface of the positive electrode active material layer, wherein the solid electrolyte interface film on the surface of the positive electrode active material layer contains S in percentage by mass as tested by an X-ray photoelectron spectrometer 2 The mass percent of nitrogen element is N 2 In which, S is 1.ltoreq.S 1 /S 2 +N 1 /N 2 And is less than or equal to 2. Sulfur from sulfur-containing additives (e.g., li) in negative electrode SEI films and positive electrode CEI films 2 S、Li 2 SO 3 Lithium alkylsulfinate RSO 2 Sulfur in Li, etc.) can improve the high temperature stability of the SEI film and the CEI film, thereby contributing to improvement of the high temperature storage performance and the high temperature cycle performance of the anode and the cathode; however, since sulfur is a poor conductor of lithium ions and electrons, when the content of sulfur is large, the kinetic performance of the electrode is affected, and the electrochemical performance of the battery is further affected. Nitrogen elements (e.g., li) from nitrogen-containing additives in SEI and CEI films 3 N, R-N-Li, etc.) can improve the conductivity of lithium ions and electrons, but may cause the SEI film to be not dense and unstable, thereby affecting the high temperature performance of the battery. The inventor of the application discovers through researches that the contents of sulfur and nitrogen in SEI and CEI films are controlled within the above range, on one hand, the SEI and CEI films are more compact and stable, the transmission performance of lithium ions at an interface is better, and further the first coulombic efficiency of the secondary battery is improved, on the other hand, the reasonable proportion of the contents of the sulfur and the nitrogen in the SEI and CEI films can effectively inhibit the continuous side reaction of electrolyte and positive and negative electrode active materials, inhibit gas production, and further improve the cycle performance and safety performance of the secondary battery, especially the cycle performance and storage performance at high temperature.
In some embodiments, S 1 /S 2 +N 1 /N 2 Is 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.6, 1.7, 1.8, 1.9, 2 or a range of any two of these values. In some embodiments, 1.ltoreq.S 1 /S 2 +N 1 /N 2 Less than or equal to 1.5. In some casesIn an embodiment, 1.ltoreq.S 1 /S 2 +N 1 /N 2 Less than or equal to 1.3. When S is 1 /S 2 +N 1 /N 2 When the content of sulfur element and nitrogen element in the SEI film is too high, the active site of the anode surface is increased, more lithium is consumed, the continuous decomposition of the electrolyte cannot be inhibited, the first coulombic efficiency of the battery is further influenced, and the cycle performance and the high-temperature performance are also influenced. When S is 1 /S 2 +N 1 /N 2 When the content is too low, the number of active sites on the surface of the anode is too small, so that the electrode interface dynamics is poor, the polarization is increased, and the cycle performance of the battery is further affected.
In some embodiments, 0.5S 1 /S 2 Less than or equal to 1.5. In some embodiments, S 1 /S 2 Is 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5 or a range of any two of these values. In some embodiments, 0.6.ltoreq.S 1 /S 2 And is less than or equal to 1. In some embodiments, 0.6.ltoreq.S 1 /S 2 Less than or equal to 0.85. When S is 1 /S 2 When the sulfur content is too high, the sulfur-containing additive is reduced more at the negative electrode, so that the effect of the additive at the positive electrode cannot be fully exerted, and the high-temperature circulation is affected, thereby deteriorating the battery performance; when S is 1 /S 2 When too low, the sulfur-containing additive is oxidized more at the positive electrode, so that the effect of the additive at the negative electrode cannot be fully exerted, high-temperature storage is affected, and the battery causes deterioration of battery performance.
In some embodiments, 0.2N 1 /N 2 Less than or equal to 0.8. In some embodiments, N 1 /N 2 A range of 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 two of these values. In some embodiments, 0.3N 1 /N 2 Less than or equal to 0.6. In some embodiments, 0.3N 1 /N 2 Less than or equal to 0.5. When N is 1 /N 2 When the content of the nitrogen-containing additive is too high, the nitrogen-containing additive is reduced more in the negative electrode, so that the irreversible capacity of the negative electrode is increased, the side reaction of the battery is increased, and the yield is increasedSevere smell; when N is 1 /N 2 When the amount of the negative electrode is too low, the electron and ion conductivity of the negative electrode SEI film of the battery is lowered, the negative electrode capacity is not normally exhibited, the polarization is increased, and the cycle stability is deteriorated.
In some embodiments, 0<S 1 And is less than or equal to 10. In some embodiments, S 1 Is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10 or any two of these values. In some embodiments, 0.2S 1 And is less than or equal to 4. In some embodiments, 0.5S 1 ≤3。
In some embodiments, 0<S 2 And is less than or equal to 10. In some embodiments, S 2 Is 0.1, 0.3, 0.5, 0.7, 1, 1.3, 1.5, 1.7, 2, 2.3, 2.5, 2.7, 3, 3.3, 3.5, 3.7, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10 or a range of any two of these values. In some embodiments, 0.3S 2 And is less than or equal to 5. In some embodiments, 0.5S 2 ≤4。
In some embodiments, 0<N 1 And is less than or equal to 10. In some embodiments, N 1 Is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10 or any two of these values. In some embodiments, 0.2N 1 And is less than or equal to 4. In some embodiments, 0.5N 1 ≤3。
In some embodiments, 0<N 2 And is less than or equal to 10. In some embodiments, N 2 Is 0.1, 0.3, 0.5, 0.7, 1, 1.3, 1.5, 1.7, 2, 2.3, 2.5, 2.7, 3, 3.3, 3.5, 3.7, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10 or a range of any two of these values. In some embodiments, 1N 2 And is less than or equal to 7. At the position ofIn some embodiments, 1.5.ltoreq.N 2 ≤6。
In some embodiments, the sulfur-containing additive comprises at least one selected from the group consisting of sulfonate, sulfate, and sulfite. The sulfur-containing additive can improve the composition and structure of the interfacial film to more effectively exert the above effects, thereby further improving the cycle performance and storage performance of the secondary battery.
In some embodiments, the sulfonate comprises at least one of the compounds of formula I-1,
formula I-1
In the formula I-1, Q 1 And Q 2 Independently selected from C1-C6 alkylene.
In some embodiments, Q 1 And Q 2 Independently selected from C1-C4 alkylene, such as methylene, ethylene or propylene. In some embodiments, the sulfonate comprises at least one of Methylene Methylsulfonate (MMDS), ethylene ethyldisulfonate, and propylene methylsulfonate.
In some embodiments, the sulfonate comprises at least one of the compounds of formula I-2,
formula I-2
In the formula I-2, R 1 、R 2 Independently selected from hydrogen atom or C1-C6 alkyl, Q 3 Selected from the group consisting of C1-C6 alkylene, C2-C6 alkenylene.
In some embodiments, in formula I-2, R 1 、R 2 Independently selected from hydrogen atom or C1-C4 alkyl, Q 3 Selected from the group consisting of C1-C4 alkylene, C2-C4 alkenylene.
In some embodiments, the sulfonate comprises at least one of 1, 3-Propane Sultone (PS), 1-propylene-1, 3-sultone (PST), and 1, 4-Butane Sultone (BS).
In some embodiments, the sulfate comprises at least one of the compounds of formula I-3,
formula I-3
In the formula I-3, R 3 、R 4 、R 5 、R 6 Independently selected from hydrogen atom or C1-C6 alkyl, Q 4 Absence or Q 4 Selected from C1-C6 alkylene.
In some embodiments, in formula I-3, R 3 、R 4 、R 5 、R 6 Independently selected from hydrogen atom or C1-C4 alkyl, Q 4 Absence or Q 4 Selected from C1-C4 alkylene.
In some embodiments, in formula I-3, R 3 、R 4 、R 5 、R 6 Independently selected from hydrogen atom, methyl, ethyl, n-propyl or isopropyl group, Q 4 Is not present.
In some embodiments, the sulfate comprises at least one of vinyl sulfate (DTD), 4-methyl ethylene sulfate (PCS), 4-ethyl ethylene sulfate (PES), 4-propyl ethylene sulfate (PEGLST), and propylene sulfate (TS).
In some embodiments, the sulfite comprises at least one of the compounds of formula I-4,
formula I-4
In the formula I-4, R 7 、R 8 、R 9 、R 10 Independently selected from hydrogen atom or C1-C6 alkyl, Q 5 Absence or Q 5 Selected from C1-C6 alkylene.
In some embodiments, in formula I-4, R 7 、R 8 、R 9 、R 10 Independently selected from hydrogen atom or C1-C4 alkyl, Q 5 Absence or Q 5 Selected from C1-C4 alkylene.
In some embodiments, the sulfite comprises ethylene sulfite (DTO).
In some embodiments, the sulfite comprises at least one of the compounds of formula I-5,
formula I-5
In the formula I-5, R 11 And R is 12 Independently selected from C1-C6 alkyl.
In some embodiments, in formula I-5, R 11 And R is 12 Independently selected from C1-C4 alkyl. In some embodiments, the sulfite comprises at least one of dimethyl sulfite (DMS) and diethyl sulfite (DES).
In some embodiments, the nitrogen-containing additive includes at least one selected from the group consisting of a nitrile compound, a phosphazene, a nitrogen-containing lithium salt, and an amide. The nitrogen-containing additive can improve the ion conductivity of the electrolyte and the composition and structure of the interface film, so that the effect can be more effectively exerted, and the cycle performance and the storage performance of the secondary battery are further improved.
In some embodiments, the nitrile compound includes at least one of the compounds represented by formula II-1,
formula II-1
In formula II-1, R 13 Selected from C2-C10 alkylene, oxygenated C2-C10 alkylene or nitrile substituted C2-C10 alkylene.
In some embodiments, in formula II-1, R 13 Selected from C2-C6 alkylene or nitrile substituted C2-C6 alkylene, for example ethylene, propylene, butylene, pentylene, hexylene, ethylene, propylene, butylene, pentylene, hexylene containing 1 or 2 oxygen atoms, or nitrile substituted ethylene, propylene, butylene, pentylene, hexylene. In some embodiments, the nitrile compound includes at least one of Succinonitrile (SN), adiponitrile (ADN), glutaronitrile (GLN), hexanetrinitrile (HTN), and ethylene glycol (bis) propionitrile ether (DENE).
In some embodiments, the phosphazene comprises at least one of the compounds of formula II-2,
formula II-2
In formula II-2, R 19 Selected from C1-C6 alkyl or fluoro C1-C6 alkyl, R 14 、R 15 、R 16 、R 17 And R is 18 Independently selected from hydrogen atom, fluorine atom, C1-C6 alkyl or fluorinated C1-C6 alkyl, and R 14 、R 15 、R 16 、R 17 And R is 18 At least one of them being a fluorine atom or a fluorinated C1-C6 alkyl group.
In some embodiments, in formula II-2, R 19 Selected from C1-C4 alkyl or fluoro C1-C4 alkyl, R 14 、R 15 、R 16 、R 17 And R is 18 Independently selected from fluorine atom, C1-C4 alkyl or fluoro C1-C4 alkyl, and R 14 、R 15 、R 16 、R 17 And R is 18 At least one of them being a fluorine atom or a fluorinated C1-C6 alkyl group.
In some embodiments, in formula II-2, R 19 Selected from methyl, ethyl, n-propyl, isopropyl, trifluoromethyl or 2, 2-trifluoroethyl, R 14 、R 15 、R 16 、R 17 、R 18 Independently selected from fluorine atoms or fluoro C1-C4 alkyl groups, and R 14 、R 15 、R 16 、R 17 And R is 18 At least one of them being a fluorine atom.
In some embodiments, the phosphazene comprises at least one of methoxy pentafluoroethylene triphosphazene, trifluoromethoxy pentafluoroethylene triphosphazene, ethoxy pentafluoroethylene triphosphazene (PFPN), and trifluoroethoxy pentafluoroethylene Triphosphazene (TFPN).
In some embodiments, the nitrogen-containing lithium salt comprises at least one of the compounds of formula II-3,
Formula II-3
In formula II-3, R 20 、R 21 Each independently selected from fluorine atom, C1-C6 alkyl or fluoro C1-C6 alkyl, and R 20 And R is 21 At least one of them being a fluorine atom or a fluorinated C1-C6 alkyl group.
In some embodiments, in formula II-3, R 20 、R 21 Each independently selected from fluorine atom, C1-C4 alkyl or fluoro C1-C4 alkyl, and R 20 And R is 21 At least one of them being a fluorine atom or a fluorinated C1-C4 alkyl group.
In some embodiments, the nitrogen-containing lithium salt includes at least one of lithium bis (fluorosulfonyl) imide (LiFSi), lithium bis (trifluoromethylsulfonyl) imide (LiTFSi), lithium bis (pentafluoroethanesulfonate) imide (LiBETI), and lithium (trifluoromethylsulfonyl) (perfluorobutylsulfonyl) imide (LiFNFSI).
In some embodiments, the nitrogen-containing lithium salt comprises at least one of the compounds of formula II-4,
formula II-4
In formula II-4, R 22 、R 23 、R 24 Each independently selected from a hydrogen atom, a fluorine atom, a C1-C6 alkyl group, a fluorinated C1-C6 alkyl group or a nitrile group, and R 22 、R 23 And R is 24 At least one of them is a fluorine atom, a fluorinated C1-C6 alkyl group or a nitrile group.
In some embodiments, in formula II-4, R 22 Is a fluorine atom or a fluorinated C1-C4 alkyl group, R 23 And R is 24 At least one of them is a nitrile group. In some embodiments, the nitrogen-containing lithium salt comprises lithium 4, 5-dicyano-2- (trifluoromethyl) imidazole (LiTDI).
In some embodiments, the amide comprises at least one of the compounds of formula II-5,
formula II-5
In formula II-5, R 25 、R 26 、R 27 Each independently selected from a hydrogen atom, a C1-C6 alkyl group or a fluorinated C1-C6 alkyl group, and R 25 、R 26 And R is 27 At least one of them is a fluorinated C1-C6 alkyl group.
In some embodiments, in formula II-5, R 25 、R 26 、R 27 Each independently selected from a hydrogen atom, a C1-C4 alkyl group or a fluorinated C1-C4 alkyl group, and R 25 、R 26 And R is 27 At least one of them is a fluorinated C1-C4 alkyl group. In some embodiments, the amide comprises trifluoroacetamide.
In some embodiments, the sulfur-containing additive is present in an amount of 0.05% to 4% by mass based on the mass of the electrolyte. In some embodiments, the sulfur-containing additive is present in an amount by mass of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4% or a range consisting of any two of these values. In some embodiments, the sulfur-containing additive is present in an amount of 0.2% to 3% by mass.
In some embodiments, the nitrogen-containing additive is present in an amount of 0.1% to 15% by mass. In some embodiments, the nitrogen-containing additive is present in an amount of 0.2%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.5%, 5%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 11%, 12%, 13%, 14%, 15% or a range of any two of these values by mass. In some embodiments, the nitrogen-containing additive is present in an amount of 0.2% to 10% by mass. In some embodiments, the nitrogen-containing additive is present in an amount of 0.2% to 4% by mass.
In some embodiments, the electrolyte further comprises other additives, the other additives include a catalyst selected from the group consisting of Vinylene Carbonate (VC), ethylene carbonate (VEC), lithium difluorophosphate (LiDFP), fluoroethylene carbonate (FEC), tris (trimethylsilyl) phosphate, tris (trimethylsilyl) borate difluoro ethylene carbonate, trifluoro propylene carbonate, 2-trifluoro methyl ethyl carbonate, 2-trifluoro diethyl carbonate at least one of tris (trifluoroethyl) phosphate and 1, 2-tetrafluoroethyl-2, 3-tetrafluoropropyl ether. In some embodiments, the other additives include at least one of vinylene carbonate, ethylene carbonate, lithium difluorophosphate, and fluoroethylene carbonate.
The mass content of the other additives is 0.1% -10% based on the mass of the electrolyte. In some embodiments, the other additive is present in an amount of 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 6%, 7%, 8%, 9% or a range of any two of these values by mass. In some embodiments, the other additive is present in an amount of 0.1% to 5% by mass.
In some embodiments, the electrolyte further comprises an electrolyte lithium salt comprising a metal selected from lithium hexafluorophosphate (LiPF 6 ) Lithium tetrafluoroborate (LiBF) 4 ) At least one of lithium trifluoromethylsulfonate (LiOTf), lithium bis (fluoromalonic) borate (LiBOB), lithium bis (fluoromalonic) borate (LiBFMB), and lithium difluorooxalato borate (LiDFOB).
In some embodiments, the lithium salt may further include at least one of lithium bis (fluorosulfonyl) imide (LiFSI), lithium bis (trifluoromethylsulfonyl) imide (LiTFSI), lithium bis (pentafluoroethylsulfonate) imide (LiBETI), (trifluoromethylsulfonyl) (perfluorobutylsulfonyl) imide (LiFNFSI), and lithium 4, 5-dicyano-2- (trifluoromethyl) imidazole (liti). In some embodiments, the concentration of the above lithium salt is 0.2 to 1.2mol/L.
In some embodiments, the electrolyte further comprises a solvent. In some embodiments, the solvent comprises at least one of a chain carbonate, a cyclic carbonate, and a carboxylate.
In some embodiments, the chain carbonate is selected from at least one of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methylethyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, and fluoro chain carbonate. In some embodiments, the cyclic carbonate comprises at least one of ethylene carbonate, propylene carbonate, and butylene carbonate. In some embodiments, the carboxylic acid ester is selected from at least one of methyl formate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, gamma-butyrolactone, and a fluorocarboxylic acid ester.
In some embodiments, the solvent comprises a chain carbonate and/or a cyclic carbonate, the mass content of which is above 90%, e.g. above 95%, 98% based on the mass of the solvent. In some embodiments, the solvent does not include a carboxylate. In some embodiments, the solvent does not include an ether.
In some embodiments, the positive electrode includes a positive electrode active material layer, and the positive electrode active material includes at least one selected from lithium nickel transition metal oxides. In some embodiments, the lithium nickel transition metal oxide has a chemical formula of LiNi m Co n A (1-m-n) O 2 Wherein A is selected from at least one of Mn, al, mg, cr, ca, zr, mo, ag or Nb, m is more than or equal to 0.5 and less than or equal to 1, n is more than or equal to 0 and less than or equal to 0.5, and m+n is more than or equal to 1.
In some embodiments, m is 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, or a range consisting of any two of these values. In some embodiments, n is 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, or a range consisting of any two of these values.
In some embodiments, the lithium nickel transition metal oxide comprises at least one of NCA, NCM111, NCM523, NCM622, NCM811, ni90, ni92, or Ni 95.
In some embodiments, the positive electrode active material may also include at least one of phosphate-based compounds having a chemical formula of LiMn k B (1-k) PO 4 Wherein k is more than or equal to 0 and less than or equal to 1, and B element is at least one of iron, cobalt, magnesium, calcium, zinc, chromium or lead. In some embodiments, k is 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, 0.85, 0.9, 0.95, or a range of any two of these values. In some embodiments, the phosphate-based compound comprises lithium iron phosphate, liMn 0.6 Fe 0.4 PO 4 Or LiMn 0.8 Fe 0.2 PO 4 At least one of them.
In some embodiments, the positive electrode active material layer further includes a binder, and optionally includes a conductive agent. The binder enhances the bonding of the positive electrode active material particles to each other and also enhances the bonding of the positive electrode active material to the current collector.
In some embodiments, the binder includes, but is not limited to: polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, an ethyleneoxy-containing polymer, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, or the like.
In some embodiments, the conductive agent includes, but is not limited to: carbon-based materials, metal-based materials, conductive polymers, and mixtures thereof. In some embodiments, the carbon-based material is selected from natural graphite, synthetic graphite, carbon black, acetylene black, ketjen black, carbon fiber, or any combination thereof. In some embodiments, the metal-based material is selected from metal powder, metal fiber, copper, nickel, aluminum, or silver. In some embodiments, the conductive polymer is a polyphenylene derivative.
In some embodiments, the positive electrode further includes a positive electrode current collector, which may be a metal foil or a composite current collector. For example, aluminum foil may be used. The composite current collector may be manufactured by a process of forming a metal material (copper, copper alloy, nickel alloy, titanium alloy, silver alloy, etc.) on a polymer substrate.
In some embodiments, the positive electrode has a porosity of 15% to 35%. In some embodiments, the porosity of the positive electrode is 15%, 17%, 19%, 20%, 22%, 24%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, or a range of any two of these values. In some embodiments, the positive electrode has a porosity of 22% to 30%.
In the present application, the porosity of the pole piece can be adjusted by conventional means in the art, such as controlling the pole piece rolling pressure, rolling temperature, rolling speed, according to the active material characteristics selected. The porosity of the pole piece is too small, the capacity of the pole piece for absorbing electrolyte is reduced, the electrolyte is difficult to infiltrate, and the polarization of the secondary battery is increased in the circulation process, so that the circulation performance of the secondary battery is affected. The porosity of the electrode plate is too large, the conductivity of the electrode is also reduced, the utilization rate of the secondary battery is reduced, and the electrochemical performance and the energy density of the secondary battery are affected.
In some embodiments, the positive electrode has a single-sided areal density of 220 to 290g/m 2 . In some embodiments, the positive electrode has a single-sided areal density of 220g/m 2 、225g/m 2 、230g/m 2 、235g/m 2 、240g/m 2 、245g/m 2 、250g/m 2 、255g/m 2 、260g/m 2 、265g/m 2 、270g/m 2 、275g/m 2 、280g/m 2 、285g/m 2 、290g/m 2 Or a range of any two of these values. In some embodiments, the positive electrode has a single-sided areal density of 230-285g/m 2 . In some embodiments, the positive electrode has a single-sided areal density of 240-280g/m 2 。
In the application, the single-sided area density of the pole piece can be adjusted according to the characteristics of the selected active substance by the conventional technical means in the field, such as controlling the thickness of a coating knife table, the coating temperature and the coating speed.
In some embodiments, the anode includes an anode active material layer, and the anode active material includes a silicon-based material. The silicon-based material includes at least one of silicon, a silicon alloy, a silicon oxygen compound, and a silicon carbon compound.
In some embodiments, the negative electrode active material further includes a mixture of at least one of a carbon-based material, a tin-based material, a phosphorus-based material, and metallic lithium. The carbon-based material includes at least one of graphite, soft carbon, hard carbon, carbon nanotubes, and graphene. The tin-based material includes at least one of tin, tin oxide, and tin alloy. The phosphorus-based material includes phosphorus and/or a phosphorus compound.
In some embodiments, the mass content g% of the silicon-based material, based on the mass of the anode active material, satisfies: g is more than or equal to 10 and less than or equal to 100. In some embodiments, g is 11, 13, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or a range of any two of these values. In some embodiments, 10.ltoreq.g.ltoreq.50. In other embodiments, 12.ltoreq.g.ltoreq.35.
In some embodiments, the anode active material layer further includes a binder and a conductive agent. In some embodiments, the binder includes, but is not limited to: polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, an ethyleneoxy-containing polymer, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, or the like.
In some embodiments, the conductive agent includes, but is not limited to: carbon-based materials, metal-based materials, conductive polymers, and mixtures thereof. In some embodiments, the carbon-based material is selected from natural graphite, synthetic graphite, carbon black, acetylene black, ketjen black, carbon fiber, or any combination thereof. In some embodiments, the metal-based material is selected from metal powder, metal fiber, copper, nickel, aluminum, or silver. In some embodiments, the conductive polymer is a polyphenylene derivative.
In some embodiments, the negative electrode further comprises a negative electrode current collector comprising: copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, or any combination thereof.
In some embodiments, the porosity of the negative electrode is 20% -40%. In some embodiments, the porosity of the negative electrode is 20%, 22%, 24%, 26%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40% or a range of any two of these values. In some embodiments, the porosity of the negative electrode is 25% -38%. In some embodiments, the porosity of the negative electrode is 28% -38%.
In some embodiments, the negative electrode has a single-sided areal density of 80-110g/m 2 . In some embodiments, the negative electrode has a single-sided areal density of 80g/m 2 、82g/m 2 、84g/m 2 、86g/m 2 、88g/m 2 、90g/m 2 、92g/m 2 、94g/m 2 、96g/m 2 、98g/m 2 、100g/m 2 、102g/m 2 、104g/m 2 、106g/m 2 、108g/m 2 、110g/m 2 Or a range of any two of these values. In some embodiments, the negative electrode has a single-sided areal density of 85-105g/m 2 . In some embodiments, the negative electrode has a single-sided areal density of 90-100g/m 2 。
In some embodiments, a separator is provided between the positive and negative electrodes to prevent shorting. The materials and shape of the separator that can be used in the embodiments of the present application are not particularly limited, and may be any of the techniques disclosed in the prior art. In some embodiments, the separator comprises a polymer or inorganic, etc., formed from a material that is stable to the electrolyte of the present application.
For example, the release film may include a substrate layer and a surface treatment layer. The substrate layer is a non-woven fabric, a film or a composite film with a porous structure, and the material of the substrate layer comprises at least one of polyethylene, polypropylene, polyethylene terephthalate or polyimide. Specifically, a polypropylene porous membrane, a polyethylene porous membrane, a polypropylene nonwoven fabric, a polyethylene nonwoven fabric or a polypropylene-polyethylene-polypropylene porous composite membrane can be selected.
The surface treatment layer is provided on at least one surface of the base material layer, and the surface treatment layer may be a polymer layer or an inorganic layer, or may be a layer formed by mixing a polymer and an inorganic substance.
The inorganic layer includes inorganic particles including at least one of aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium oxide, 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, and a binder. The binder comprises at least one of polyvinylidene fluoride, copolymer of vinylidene fluoride-hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene or polyhexafluoropropylene.
The polymer layer contains a polymer, and the material of the polymer comprises at least one of polyamide, polyacrylonitrile, acrylic polymer, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polyvinylidene fluoride or poly (vinylidene fluoride-hexafluoropropylene).
In some embodiments, the method of manufacturing the secondary battery includes providing an electrode assembly, injecting a liquid, packaging, and forming. In some embodiments, the temperature of the formation is from 30 ℃ to 60 ℃, such as 30 ℃, 32 ℃, 35 ℃, 38 ℃, 41 ℃, 42 ℃, 43 ℃, 44 ℃, 45 ℃, 46 ℃, 47 ℃, 48 ℃, or 49 ℃. In some embodiments, the temperature of the formation is 40-50 ℃. In some embodiments, the pressure of the formation is from 150kgf to 280kgf, for example 160kgf, 170kgf, 180kgf, 190kgf, 200kgf, 210kgf, 220kgf, 230kgf, 240kgf, 250kgf, 260kgf, 270kgf, 280kgf. In some embodiments, the charging current of the formation is 0.05C-0.1C and the discharging current of the formation is 0.1C-0.3C.
In some embodiments, the forming comprises: charging to 4.2V at a current of 0.05C under a condition of a temperature of 40-50 deg.C, for example 45 deg.C, and a pressure of 150-250 kgf, for example 200kgf, standing for 60min, then charging to 4.2V at 0.1C, and then discharging to 3.0V at 0.2C.
In some embodiments, the secondary battery is a lithium secondary battery or a sodium secondary battery. In some embodiments, lithium secondary batteries include, but are not limited to: lithium metal secondary batteries, lithium ion secondary batteries, lithium polymer secondary batteries, or lithium ion polymer secondary batteries.
In some embodiments, the secondary battery may include an outer package, which may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, or the like. The exterior package of the secondary battery may also be a pouch type pouch, for example. The soft bag can be made of one or more of polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), etc.
In some embodiments, the shape of the secondary battery is not particularly limited, and may be cylindrical, square, or any other shape.
In some embodiments, the application also provides a battery module. The battery module includes the secondary battery described above. The battery module of the present application employs the above-described secondary battery, and thus has at least the same advantages as the secondary battery. The number of secondary batteries included in the battery module of the present application may be plural, and the specific number may be adjusted according to the application and capacity of the battery module.
In some embodiments, the present application also provides a battery pack including the above battery module. The number of battery modules included in the battery pack may be adjusted according to the application and capacity of the battery pack.
2. Device and method for controlling the same
The present application also provides an apparatus comprising at least one of the above secondary battery, battery module or battery pack.
In some embodiments, the apparatus includes, but is not limited to: electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric storage systems, and the like. In order to meet the high power and high energy density requirements of the device for the secondary battery, a battery pack or a battery module may be employed.
In other embodiments, the device may be a cell phone, tablet, notebook, or the like. The device is generally required to be light and thin, and a secondary battery can be used as a power source.
Examples
Test method
1. Determination of porosity of Pole pieces
The porosity is measured by a mercury porosimeter, and is specifically as follows: the dried pole piece samples were slit into strips of a certain size and the apparent volume of the pole piece coating was determined using a ten-thousandth ruler, apparent volume = sample coating thickness x sample length x sample width. The pole piece is then vacuum degassed and wound in a sample cell, the sample volume must be ensured to be 40-70% of the effective volume of the sample tube, so as to ensure measurement accuracy, and then the pore volume of the sample, i.e. the volume of mercury pressed into the sample, is measured using a mercury porosimeter, then the porosity = pore volume/apparent volume.
2. First coulombic efficiency test of battery
The lithium ion secondary battery was charged to 4.2V at a constant current of 1C at 25C, then charged at a constant voltage to a current of less than 0.05C, and the initial charge capacity was recorded. After standing for 5 minutes, the initial discharge capacity was recorded by discharging again to 2.5V at a constant current of 1C. First coulombic efficiency=initial discharge capacity/initial charge capacity×100% of the lithium ion secondary battery.
3. Battery cycle capacity retention test
The lithium ion battery is charged to 4.25V at a constant current of 1C at 25 ℃, then charged to 0.05C at a constant voltage of 4.25V, and then discharged to 2.5V at a constant current of 1C. After 1000 cycles of charge and discharge, the capacity retention rate after the 1000 th cycle at 25℃was calculated according to the following formula: discharge capacity after 1000 th cycle/discharge capacity at first cycle x 100%.
The lithium ion battery is charged to 4.25V at a constant current of 1C at 50 ℃, then charged to 0.05C at a constant voltage of 4.25V, and then discharged to 2.5V at a constant current of 1C. After 500 cycles of charge and discharge, the capacity retention after 500 cycles at 50℃was calculated according to the following formula: the discharge capacity after 500 th cycle/the discharge capacity after first cycle is multiplied by 100%.
4. Storage thickness change rate of battery at 50 DEG C
The cell was discharged to 3.0V at 25 ℃ with a constant current of 0.5C, charged to 4.45V with a constant current of 0.5C, then charged to 0.05C with a constant voltage of 4.45V, and the thickness of the cell was measured using a PPG soft pack cell thickness gauge and recorded as a. The battery was placed in an oven and stored at a constant pressure of 4.45V for 21 days at 50 ℃ for 21 days, and the thickness after 21 days of testing was noted as b, and the calculation formula of the thickness expansion ratio was as follows: (b-a)/a.times.100%.
5. CEI film and SEI film sulfur and Nitrogen content test
Discharging the lithium ion battery to 2.5V at the current of 0.1C, and dismantling the lithium ion battery in a glove box filled with argon to obtain the electrode plate. Cutting the obtained electrode plate into test samples with the size of 8mm multiplied by 8mm, soaking and cleaning for half an hour by using a low-boiling point dimethyl carbonate (DMC) solvent, after the test samples are completely dried, pasting the test samples on a sample table of XPS, enabling the surface of the positive electrode active material layer or the negative electrode active material layer, which is far away from a current collector, to face upwards, and measuring under the condition of not being exposed to the atmosphere. The specific test conditions and steps are as follows:
the elemental percentages of elemental sulfur and elemental nitrogen in the positive or negative electrode SEI were calculated using single crystal spectral alkα radiation, using 1000X 1750 μm ellipsometry output of 10KV and 22mA for the X-ray points, selecting data for sputter etch time of 0 seconds, using 284.8eV for neutral carbon C1s, and using 3-point smoothing, peak area measurement, background subtraction and peak synthesis for data processing such as peak differentiation.
Example 1
The preparation method of the positive electrode comprises the following steps: the positive electrode active material LiNi 0.9 Co 0.05 Mn 0.05 O 2 The conductive agent carbon nano tube/acetylene black, the binder polyvinylidene fluoride PVDF, and the weight ratio of LiNi 0.9 Co 0.05 Mn 0.05 O 2 After being sufficiently homogenized in an N-methylpyrrolidone NMP solvent system, CNT/Super-P =95:2.0/1.0:2 was coated on an aluminum-coated current collector having a thickness of 12 μm, dried and rolled to obtain a positive electrode sheet, wherein the positive electrode porosity was 25.4%.
The preparation method of the negative electrode comprises the following steps: silicon oxide (SiO) as a negative electrode active material x X is more than or equal to 0.5 and is less than or equal to 1.5), graphite compound (the mass ratio of silicon oxide to graphite in the compound is 14:86), conductive agent acetylene black, adhesive styrene-butadiene rubber SBR, thickener sodium carboxymethyl cellulose CMCNa and polyacrylic acid PAA are fully homogenized in deionized water according to the weight ratio of 96:2:1.5:1.5, then the mixture is coated on the surface of an 8 mu m thick copper current collector, and the negative pole piece is obtained after drying, rolling and stripping, wherein the porosity of the negative pole is 33.5%.
A diaphragm: adopts a PP/PE/PP three-layer composite diaphragm.
Preparing an electrolyte: in an argon-filled glove box (H) 2 O＜0.1ppm，O 2 < 0.1 ppm), lithium salt LiPF 6 And solvent EC/DEC/emc=25/20/55 were uniformly mixed in a certain ratio to prepare a 1M solution, and finally, the sulfur-containing compound additive (0.5% by total mass of the electrolyte) and the nitrogen-containing compound additive (1% by total mass of the electrolyte) in table 1 were added, and the solution was uniformly stirred to obtain a lithium ion battery electrolyte of example 1.
Preparation of a lithium ion battery: sequentially stacking the prepared positive pole piece, the diaphragm and the negative pole piece, enabling the diaphragm to be positioned between the positive pole piece and the negative pole piece, and winding to obtain a bare cell; the bare cell is placed in an aluminum plastic film outer package, the prepared lithium ion battery electrolyte is injected after the bare cell is fully dried, the battery is placed at 45 ℃ for 48 hours and is formed by high-temperature clamping (the formation condition is that the temperature is 45 ℃, the pressure is 210kgf, the current is charged to 4.2V for 60 minutes, then the current is charged to 4.2V at 0.1C, then the current is discharged to 3.0V at 0.2C, and the process is repeated twice) and the secondary sealing is carried out, and then the conventional capacity division is carried out.
Examples 2 to 15 and comparative examples 1 to 11
Examples 2 to 15 and comparative examples 1 to 11 were carried out on the basis of example 1 by adjusting the kinds and contents of additives in the electrolyte, the porosity and the single-sided area density of the electrode sheet (wherein the porosity is achieved by adjusting the line load of the electrode sheet roller during the preparation, etc.), and the formation conditions, and specific adjustment measures and detailed data are shown in table 1.
TABLE 1
The battery performance test results of examples 1 to 15 and comparative examples 1 to 11 are shown in Table 2.
TABLE 2
While certain exemplary embodiments of the application have been illustrated and described, the application is not limited to the disclosed embodiments. Rather, one of ordinary skill in the art will recognize that certain modifications and changes may be made to the described embodiments without departing from the spirit and scope of the present application as described in the appended claims.

Claims (11)

1. A secondary battery includes a positive electrode, a negative electrode, and an electrolyte, wherein,
the electrolyte includes a sulfur-containing additive and a nitrogen-containing additive;
the anode comprises an anode active material layer and a solid electrolyte interface film positioned on the surface of the anode active material layer, wherein the solid electrolyte interface film is obtained through formation, and is tested by adopting an X-ray photoelectron spectrometer under the condition of sputtering etching time of 0 second, and the mass percentage of sulfur element in the solid electrolyte interface film on the surface of the anode active material layer is S 1 The mass percent of nitrogen element is N 1 %，
The positive electrode comprises a positive electrode active material layer and a solid electrolyte interface film positioned on the surface of the positive electrode active material layer, wherein the solid electrolyte interface film is obtained through formation, and is tested by adopting an X-ray photoelectron spectrometer under the condition of sputtering etching time of 0 seconds, and the mass percentage of sulfur element in the solid electrolyte interface film on the surface of the positive electrode active material layer is S 2 The mass percent of nitrogen element is N 2 %，
Wherein S is more than or equal to 1 1 /S 2 +N 1 /N 2 ≤2，0.2≤S 1 <4，0.2≤N 1 ≤4；
The sulfur-containing additive comprises at least one selected from the group consisting of sulfonate, sulfate and sulfite; the nitrogen-containing additive includes at least one selected from the group consisting of a nitrile compound, a phosphazene, a nitrogen-containing lithium salt, and an amide.
2. The secondary battery according to claim 1, wherein 1.ltoreq.S 1 /S 2 +N 1 /N 2 ≤1.5。
3. The secondary battery according to claim 1 or 2, wherein 0.5.ltoreq.s 1 /S 2 Not more than 1.5, and/or, 0.2 not more than N 1 /N 2 ≤0.8。
4. The secondary battery according to claim 1 or 2, wherein 0.6.ltoreq.s 1 /S 2 Not more than 1, and/or, 0.3 not more than N 1 /N 2 ≤0.6。
5. The secondary battery according to claim 1 or 2, wherein 0.3.ltoreq.s 2 Less than or equal to 5, and/or, 1 less than or equal to N 2 ≤7。
6. The secondary battery according to claim 1 or 2, wherein the sulfonate comprises at least one of compounds represented by formula I-1 and formula I-2,
formula I-1, ">Formula I-2
In the formula I-1, Q 1 And Q 2 Independently selected from C1-C6 alkylene, in formula I-2, R 1 、R 2 Independently selected from hydrogen atom or C1-C6 alkyl, Q 3 Selected from C1-C6 alkylene, C2-C6 alkenylene;
the sulfate comprises at least one of the compounds shown in the formula I-3,
formula I-3
In the formula I-3, R 3 、R 4 、R 5 、R 6 Independently selected from hydrogen atom or C1-C6 alkyl, Q 4 Absence or Q 4 Selected from C1-C6 alkylene;
the sulfite comprises at least one of the compounds shown in the formula I-4 and the formula I-5,
formula I-4, ">Formula I-5
In the formula I-4, R 7 、R 8 、R 9 、R 10 Independently selected from hydrogen atom or C1-C6 alkyl, Q 5 Absence or Q 5 Selected from C1-C6 alkylene, of formula I-5, R 11 And R is 12 Independently selected from C1-C6 alkyl; and/or the number of the groups of groups,
the nitrile compound includes at least one of the compounds represented by formula II-1,
formula II-1
In formula II-1, R 13 Selected from C2-C10 alkylene, oxygenated C2-C10 alkylene, or nitrile substituted C2-C10 alkylene;
the phosphazene comprises at least one of compounds shown in a formula II-2,
formula II-2
In formula II-2, R 19 Selected from C1-C6 alkyl or fluoro C1-C6 alkyl, R 14 、R 15 、R 16 、R 17 、R 18 Independently selected from hydrogen atom, fluorine atom, C1-C6 alkyl or fluorinated C1-C6 alkyl, and R 14 、R 15 、R 16 、R 17 、R 18 At least one of them is a fluorine atom or a fluorinated C1-C6 alkyl group;
the nitrogen-containing lithium salt comprises at least one of the compounds shown in the formulas II-3 and II-4,
formula II-3, -/->Formula II-4
In formula II-3, R 20 、R 21 Each independently selected from fluorine atom, C1-C6 alkyl or fluoro C1-C6 alkyl, and R 20 And R is 21 At least one of them is a fluorine atom or a fluorinated C1-C6 alkyl group, in the formula II-4, R 22 、R 23 、R 24 Each independently selected from a hydrogen atom, a fluorine atom, a C1-C6 alkyl group, a fluorinated C1-C6 alkyl group or a nitrile group, and R 22 、R 23 And R is 24 At least one of them is a fluorine atom, a fluorinated C1-C6 alkyl group or a nitrile group;
the amide comprises at least one of the compounds represented by formula II-5,
formula II-5
In formula II-5, R 25 、R 26 、R 27 Each independently selected from a hydrogen atom, a C1-C6 alkyl group or a fluorinated C1-C6 alkyl group, and R 25 、R 26 And R is 27 At least one of them is a fluorinated C1-C6 alkyl group.
7. The secondary battery according to claim 6, wherein the sulfonate ester comprises at least one of methyl methylene disulfonate, ethyl ethylene disulfonate, methyl propylene disulfonate, 1, 3-propane sultone, 1-propylene-1, 3-sultone, and 1, 4-butane sultone, and/or,
the sulfate comprises at least one of vinyl sulfate, 4-methyl ethylene sulfate, 4-ethyl ethylene sulfate, 4-propyl ethylene sulfate and propylene sulfate, and/or,
the sulfite comprises at least one of ethylene sulfite, dimethyl sulfite and diethyl sulfite, and/or,
the nitrile compound includes at least one of succinonitrile, adiponitrile, glutaronitrile, hexanetrinitrile and ethylene glycol (bis) propionitrile ether, and/or,
the phosphazenes comprise at least one of methoxy pentafluoroethyl triphosphazene, trifluoromethoxy pentafluoroethyl triphosphazene, ethoxy pentafluoroethyl triphosphazene and trifluoroethoxy pentafluoroethyl triphosphazene, and/or,
the nitrogen-containing lithium salt includes at least one of lithium bis (fluorosulfonyl) imide, lithium bis (pentafluoroethyl sulfonate) imide, lithium (trifluoromethylsulfonyl) (perfluorobutylsulfonyl) imide, and lithium 4, 5-dicyano-2- (trifluoromethyl) imidazole, and/or,
The amide comprises trifluoroacetamide.
8. The secondary battery according to claim 1 or 2, wherein the mass content of the sulfur-containing additive is 0.05% to 4% based on the mass of the electrolyte; and/or the number of the groups of groups,
the mass content of the nitrogen-containing additive is 0.1% -15% based on the mass of the electrolyte; and/or the number of the groups of groups,
the electrolyte further comprises other additives, wherein the other additives comprise at least one of ethylene carbonate, lithium difluorophosphate and fluoroethylene carbonate, and the mass content of the other additives is 0.1-10% based on the mass of the electrolyte; and/or the number of the groups of groups,
the electrolyte includes a solvent including a chain carbonate and/or a cyclic carbonate, the mass content of the chain carbonate and/or the cyclic carbonate being 90% or more based on the mass of the solvent.
9. The secondary battery according to claim 1 or 2, wherein the positive electrode comprises an active material selected from lithium nickel transition metal oxides having a chemical formula of LiNi m Co n A (1-m-n) O 2 Wherein, A is selected from at least one of manganese, aluminum, magnesium, chromium, calcium, zirconium, molybdenum, silver or niobium, m is more than or equal to 0.5 and less than or equal to 1, n is more than or equal to 0 and less than or equal to 0.5, and m+n is more than or equal to 1; and/or the number of the groups of groups,
The negative electrode includes an active material selected from a silicon-based material including at least one of silicon, a silicon alloy, a silicon oxygen compound, and a silicon carbon compound, and the mass content g% of the silicon-based material, based on the mass of the negative electrode active material, satisfies: g is more than or equal to 10 and less than or equal to 100.
10. The secondary battery according to claim 1 or 2, wherein the positive electrode has a porosity of 15% to 35%, and/or,
the porosity of the negative electrode is 20% -40%, and/or,
the single-sided surface density of the positive electrode is 220-290g/m 2 And/or,
the single-sided surface density of the negative electrode is 80-110g/m 2 。
11. An apparatus comprising the secondary battery according to any one of claims 1 to 10.
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