CN116487706B - Secondary battery and device - Google Patents

Secondary battery and device Download PDF

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CN116487706B
CN116487706B CN202310723219.3A CN202310723219A CN116487706B CN 116487706 B CN116487706 B CN 116487706B CN 202310723219 A CN202310723219 A CN 202310723219A CN 116487706 B CN116487706 B CN 116487706B
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secondary battery
positive electrode
active material
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CN116487706A (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

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  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
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  • General Physics & Mathematics (AREA)
  • Inorganic Chemistry (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Physics & Mathematics (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)

Abstract

The present application relates to a secondary battery and an apparatus. The secondary battery comprises a positive electrode plate, a negative electrode plate and electrolyte; the electrolyte comprises a boron-containing additive and a phosphorus-containing additive; the positive electrode plate 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 positive electrode active material layer comprises a positive electrode active material, the positive electrode active material comprises lithium nickel transition metal oxide, and the nickel element in the positive electrode active material accounts for Y% of the transition metal element in mole percentage; the mass percentage of boron element in the solid electrolyte interface film is X by adopting an X-ray photoelectron spectrometer for testing 1 The mass percentage of the phosphorus element in the solid electrolyte interface film is X 2 The%; wherein 0.7 is less than or equal to 0.02Y-0.5X 1 ‑0.5X 2 And is less than or equal to 1. Thus, the secondary battery of the present application has at least one of the following advantages: high coulombic efficiency, excellent cycle performance, storage performance and safety performance.

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 is used as a green rechargeable battery, has the advantages of higher energy density, higher power density and the like, is widely applied to various fields, is a preferred battery of portable electronic products, and is also an ideal battery of a power automobile. With the continuous progress of technology, the application range of lithium ion batteries will be wider and wider, and the lithium ion batteries become an important component in the future energy field. In order to better meet the application requirements, the energy density of the current lithium ion battery needs to be further improved, and currently, the improvement of the content of nickel element in the ternary positive electrode is one of common ways.
However, the current secondary battery and device have yet to be improved.
Disclosure of Invention
The inventor finds that in a battery system with higher nickel element content of the positive electrode plate, lithium vacancies can be formed along with the deintercalation of lithium ions from the positive electrode plate during charging, and at the moment, nickel elements can migrate to the lithium vacancies to cause mixed discharge, even along with the deintercalation of lithium ions from the surface of the positive electrode plate, dissolve out into electrolyte and are embedded into the negative electrode plate, so that the problem of short circuit is caused. In order to alleviate or solve at least one of the above-mentioned problems, the present application provides a secondary battery and related apparatus. According to the secondary battery, the nickel element in the positive electrode active material accounts for the mole percentage content of the transition metal element, the boron element content in the solid electrolyte interface film (CEI film) formed on the surface of the positive electrode active material layer and the phosphorus element content in the solid electrolyte interface film formed on the surface of the positive electrode active material layer are controlled, so that the solid electrolyte interface film is more compact and stable, the dissolution of transition metal ions such as nickel (Ni) in a positive electrode plate is effectively inhibited, and the short circuit problem is avoided; in addition, the positive electrode active material has good synergistic effect among the mole percentage content of nickel element, the boron element content in the CEI film and the phosphorus element content in the CEI film, so that the stability of the interface between the positive electrode plate and the electrolyte is improved, the side reaction is reduced, the attenuation of the battery capacity is relieved, and the cycle performance of the secondary battery is remarkably improved.
A first aspect of the present application provides a secondary battery including a positive electrode tab, a negative electrode tab, and an electrolyte; the electrolyte comprises a boron-containing additive and a phosphorus-containing additive; the positive electrode plate 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 positive electrode active material layer comprises a positive electrode active material, the positive electrode active material comprises lithium nickel transition metal oxide, and the nickel element in the positive electrode active material accounts for Y% of the transition metal element in mole percentage; the mass percentage of boron element in the solid electrolyte interface film is X by adopting an X-ray photoelectron spectrometer for testing 1 The mass percentage of the phosphorus element in the solid electrolyte interface film is X 2 The%; wherein 0.7 is less than or equal to 0.02Y-0.5X 1 -0.5X 2 ≤1。
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:
according to the secondary battery, the nickel element in the positive electrode active material accounts for the mole percentage content of the transition metal element, the boron element content in the solid electrolyte interface film (CEI film) formed on the surface of the positive electrode active material layer and the phosphorus element content in the solid electrolyte interface film formed on the surface of the positive electrode active material layer are controlled, so that the CEI film is more compact and stable, the dissolution of transition metal ions such as nickel (Ni) in the positive electrode plate can be effectively inhibited, the problem of short circuit caused by the fact that the dissolved transition metal ions are embedded into the negative electrode plate is relieved, the damage of the transition metal ions to the negative electrode plate is inhibited, the stability of the negative electrode plate is improved, and the capacity retention rate of the secondary battery is improved. Meanwhile, the nickel element content in the positive electrode active material, the boron element content in the CEI film and the phosphorus element content in the CEI film have good synergistic effect, so that the stability of the interface between the positive electrode plate and the electrolyte is improved, the side reaction is reduced, the attenuation of the battery capacity is relieved, and the cycle performance of the secondary battery is remarkably improved; in addition, the synergistic effect further reduces the impedance of the battery and improves the power of the battery. Based on the above improvement, the secondary battery of the present application has at least one of the following advantages: high coulombic efficiency, excellent cycle performance, storage performance and safety performance.
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," "at least one of," or other similar terms are connected 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 term "C1-C6 alkyl" includes, but is not limited to: methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, n-pentyl, isopentyl, neopentyl, cyclopentyl, methylcyclopentyl, n-hexyl, isohexyl, cyclohexyl and the like.
The term "C1-C6 alkoxy" includes, but is not limited to: methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, tert-butoxy, n-pentoxy, isopentoxy, n-hexoxy, and the like.
The term "C3-C6 alkylsilyl" refers to a silicon group having 3 to 6 carbon atoms, including but not limited to: trimethylsilyl, and the like.
The term "C2-C6 alkenyl" includes, but is not limited to: ethenyl, propenyl, butenyl, pentenyl or hexenyl, and the like.
The term "C6-C12 aryl" includes, but is not limited to: phenyl, naphthyl, and the like.
The term "substituted or unsubstituted" means that the functional group recited after the term may or may not have a substituent. For example, "substituted or unsubstituted C1-C6 alkyl" refers to C1-C6 alkyl having a substituent or unsubstituted C1-C6 alkyl. Wherein the number of the substituents can be 1 or more than 2, and the substituents comprise at least one of halogen, alkyl or aryl. It will be appreciated that when the number of substituents is greater than 1, the substituents may be the same or different.
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 plate, a negative electrode plate and electrolyte; the electrolyte comprises a boron-containing additive and a phosphorus-containing additive; the positive electrode plate 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 positive electrode active material layer comprises a positive electrode active material, the positive electrode active material comprises lithium nickel transition metal oxide, and the nickel element in the positive electrode active material accounts for Y% of the transition metal element in mole percentage; the mass percentage of boron element in the solid electrolyte interface film is X by adopting an X-ray photoelectron spectrometer for testing 1 The mass percentage of the phosphorus element in the solid electrolyte interface film is X 2 The%; wherein 0.7 is less than or equal to 0.02Y-0.5X 1 -0.5X 2 ≤1。
In order to improve the energy density of the lithium ion battery, the nickel element content in the positive electrode sheet can be improved. However, in a secondary battery system with higher nickel content, lithium ions are deintercalated from the positive electrode plate during charging, lithium vacancies are formed, at this time, nickel elements migrate to the lithium vacancies to cause mixed arrangement, and even are deintercalated from the surface of the positive electrode plate along with lithium ions, dissolve into electrolyte, and are embedded into the negative electrode plate, so that the problem of short circuit is caused. According to the secondary battery, the content of nickel element in the positive electrode active material, the content of boron element in the CEI film and the content of phosphorus element in the CEI film are controlled, so that on one hand, the CEI film is more compact and stable, and the dissolution of transition metal ions such as nickel (Ni) in the positive electrode plate can be effectively inhibited, so that the problem of short circuit caused by the fact that the dissolved transition metal ions are embedded into the negative electrode plate is relieved, the damage of the transition metal ions to the negative electrode plate is inhibited, the stability of the negative electrode plate is improved, and the capacity retention rate of the secondary battery is improved. On the other hand, the nickel element content in the positive electrode active material, the boron element content in the CEI film and the phosphorus element content in the CEI film have good synergistic effect, so that the stability of the interface between the positive electrode plate and the electrolyte is improved, the side reaction is reduced, the attenuation of the battery capacity is relieved, and the cycle performance of the secondary battery is remarkably improved. In addition, the synergistic effect further reduces the impedance of the battery and improves the power of the battery. Based on the above improvement, the secondary battery of the present application has at least one of the following advantages: high coulombic efficiency, excellent cycle performance, storage performance and safety performance.
In some embodiments, 0.02Y to 0.5X 1 -0.5X 2 0.7, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1 or any value therebetween. In some embodiments, 0.8.ltoreq.0.02Y-0.5X 1 -0.5X 2 Less than or equal to 0.9. In some embodiments, when 0.02Y-0.5X 1 -0.5X 2 When the value is too large, correspondingly, the nickel element content of the positive electrode plate is higher, the boron element content in the CEI film is lower or the phosphorus element content in the CEI film is lower, the protection of the positive electrode plate is incomplete, the direct side reaction of the positive electrode plate and the electrolyte is aggravated, active lithium loss and capacity attenuation are caused, and the cycle performance is further affected. When 0.02Y-0.5X 1 -0.5X 2 When the value is too small, correspondingly, the nickel element content of the positive electrode plate is low, the boron element content of the CEI film is high or the phosphorus element content of the CEI film is high, the CEI film of the positive electrode plate is thicker, the impedance is increased, the intercalation and deintercalation of lithium ions are blocked, and the electrochemical performance and the energy density of the secondary battery are affected.
In some embodiments, 70.ltoreq.Y.ltoreq.95. In some embodiments, Y is 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, or any value therebetween. In some embodiments, 80.ltoreq.Y.ltoreq.90. It is understood that the mole percentage content of nickel element is a ratio based on the total mole amount of all transition metal elements in the positive electrode active material.
In some embodiments, 0.4.ltoreq.X 1 Less than or equal to 1.2. In some embodiments, X 1 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0, 1.05, 1.1, 1.15, 1.2 or any value therebetween. In some embodiments, 0.6.ltoreq.X 1 ≤0.9。
In some embodiments, 0.6.ltoreq.X 2 Less than or equal to 1.2. In some embodiments, X 2 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0, 1.05, 1.1, 1.15, 1.2 or any value therebetween. In some embodiments, 0.8.ltoreq.X 2 ≤1。
In some embodiments, the boron-containing additive comprises an oxalic acid borate additive. The oxalic acid borate additive can further improve the composition and structure of the interfacial film, so that the CEI film is more compact and stable, and the effect is more effectively exerted, thereby further improving the cycle performance and storage performance of the secondary battery. In addition, the above-mentioned oxalato borate additive may also undergo reduction on the surface of the anode active material layer to form a firm solid electrolyte interface film (SEI film), thereby improving the stability of the anode active material layer.
In some embodiments, the oxalato borate additive comprises at least one of the compounds represented by formula I and formula II:
A formula I; />A formula II;
in the formula I, A 1 + Selected from metal ions or organic cations;
in the formula II, A 2 + Selected from metal ions or organic cations, R 1 、R 2 Each independently selected from substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkoxy, or halogen, wherein the substituted substituent is selected from halogen selected from fluorine, chlorine, bromine, or iodine.
In some embodiments, in formula I, the metal ion is selected fromFrom Li + 、Na + Or K + The organic cation is selected from ammonium ion, trimethylamine ion, pyridinium ion or imidazolium ion.
In some embodiments, in formula II, the metal ion is selected from Li + 、Na + Or K + The organic cation is selected from ammonium ion, trimethylamine ion, pyridinium ion or imidazolium ion, R 1 、R 2 Each independently selected from fluoro-substituted C1-C6 alkyl, fluoro-substituted C1-C6 alkoxy, or fluoro.
In some embodiments, the boron-containing additive includes at least one of lithium bis (oxalato) borate (LiBOB) and lithium difluoro (oxalato) borate (lidaob). Therefore, the oxalic acid borate additive can further improve the composition and structure of the interfacial film, so that the CEI film is more compact and stable, and the effect can be more effectively exerted, thereby further improving the cycle performance and the storage performance of the secondary battery.
In some embodiments, the boron-containing additive is present in an amount of 0.1% to 3% by mass based on the mass of the electrolyte. In some embodiments, the boron-containing additive is 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, 1%, 1.1%, 1.3%, 1.5%, 1.7%, 1.9%, 2%, 2.1%, 2.3%, 2.5%, 2.7%, 2.9%, 3% or any value therebetween by mass. In some embodiments, the boron-containing additive is present in an amount of 0.5% to 2% by mass.
In some embodiments, the phosphorus-containing additive comprises at least one of the compounds of formula III and formula IV:
formula III; />A formula IV;
in the formula III and the formula IV, R 3 、R 4 、R 5 、R 6 、R 7 、R 8 Each independently selected from the group consisting of substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkoxy, and substitutedOr unsubstituted C3-C6 alkylsilyl, substituted or unsubstituted C2-C3 alkenyl, or substituted or unsubstituted C6-C12 aryl, wherein the substituted substituents are each independently selected from halogen selected from fluorine, chlorine, bromine, or iodine. Therefore, the addition of the phosphorus-containing additive can reduce the interface impedance of the anode and the cathode and improve the power of the battery. In addition, the oxalic acid borate additive and the phosphorus-containing additive are used together, so that the compactness and stability of the CEI film can be further improved, the dissolution of transition metal ions can be further inhibited, and the cycle performance of the battery can be greatly improved. Furthermore, the nickel element content in the positive electrode active material, the boron element content in the CEI film and the phosphorus element content in the CEI film have good synergistic effect, so that the stability of the interface between the positive electrode plate and the electrolyte is improved, the side reaction is reduced, the attenuation of the battery capacity is relieved, and the cycle performance of the secondary battery is remarkably improved.
In some embodiments, formula III is a phosphate additive. Under high potential, the phosphate additive can be oxidized and decomposed on the surface of the high-nickel positive electrode plate to generate a layer of positive electrode solid electrolyte interface (CEI film) rich in lithium ion conducting performance, and the CEI film can well reduce polarization voltage in the charge and discharge process, isolate the contact between electrolyte and the positive electrode, reduce the decomposition of the electrolyte, inhibit the dissolution of metal ions of the positive electrode plate, stabilize the crystal structure of the positive electrode active material, and improve the cycle performance and rate performance of the battery. In some embodiments, formula IV is a phosphite additive. After a large amount of lithium ions are deintercalated in the high-nickel positive electrode plate lattice, the stability of lattice oxygen is reduced, so that active oxygen is triggered to be separated out, and separated oxygen free radicals have stronger oxidability, can cause oxidative decomposition of electrolyte, and aggravate side reactions. The phosphite additive has unsaturated phosphate functional groups, and can react with active oxygen precipitated by the positive electrode plate to form saturated phosphate compounds, so that the active oxygen is captured, and the electrolyte is prevented from being oxidized and decomposed by the precipitated active oxygen. Therefore, the addition of the phosphite additive effectively reduces the precipitation of active oxygen on the positive electrode plate side, can reduce the activity of the precipitated active oxygen, inhibits side reactions such as oxidative decomposition of electrolyte and the like, and further remarkably improves the cycle performance of the secondary battery.
In some embodiments, in formulas III and IV, R 3 、R 4 、R 5 、R 6 、R 7 、R 8 Each independently selected from substituted or unsubstituted C1-C3 alkyl, substituted or unsubstituted C3-C6 alkylsilyl, substituted or unsubstituted C2-C3 alkenyl, or substituted or unsubstituted C6-C12 aryl, wherein each of the substituted substituents is independently selected from fluorine.
In some embodiments, the phosphorus-containing additive comprises at least one of the following compounds:
(tris (trimethylsilyl) phosphate, TMSP),(trimethyl phosphate, TMP),>(tris (2, 2-trifluoroethyl) phosphate, TFEP), and->(triphenyl phosphate, TPP),、/>. Therefore, the compactness and stability of the CEI film can be further improved, the dissolution of transition metal ions is further inhibited, and the cycle performance of the battery is greatly improved.
In some embodiments, the phosphorus-containing additive comprises at least one of the following compounds:
(tris (trimethylsilyl) phosphite, TMSPI),(trimethyl phosphite, TMPi), -/-, and>(tris (2, 2-trifluoroethyl) phosphite, TFEPi), -a->(triphenyl phosphite, TPPi),、/>. Therefore, the compactness and stability of the CEI film can be further improved, the dissolution of transition metal ions is further inhibited, and the cycle performance of the battery is greatly improved.
In some embodiments, the phosphorous-containing additive is present in an amount of 0.1% to 3% by mass based on the mass of the electrolyte. In some embodiments, the phosphorous-containing additive is 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, 1%, 1.1%, 1.3%, 1.5%, 1.7%, 1.9%, 2%, 2.1%, 2.3%, 2.5%, 2.7%, 2.9%, 3% or any value therebetween by mass. In some embodiments, the phosphorous-containing additive is present in an amount of 0.5% to 2% by mass.
In some embodiments, the electrolyte further includes a first additive including at least one of a cyclic carbonate containing a carbon-carbon double bond, a nitrile compound, and a pyridinium propanesulfonate. In some embodiments, the first additive is selected from at least one of Vinylene Carbonate (VC), ethylene carbonate, succinonitrile, adiponitrile, glutaronitrile, and hexanetrinitrile.
In some embodiments, the first additive is present in an amount of 0.05% to 10% by mass based on the mass of the electrolyte. In some embodiments, the first additive is 0.05%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 6%, 7%, 8%, 9%, 10% by mass or any value therebetween. In some embodiments, the first additive is present in an amount of 0.1% to 5% by mass.
In some embodiments, the electrolyte further comprises a lithium salt selected from lithium hexafluorophosphate (LiPF 6 ) Lithium tetrafluoroborate (LiBF) 4 ) At least one of lithium trifluorosulfonyl (LiTf), lithium bis (fluorosulfonyl) imide (LiLiLiFSI), (trifluoromethylsulfonyl) (perfluorobutylsulfonyl) imide (LiNFSI), lithium bis (trifluoromethylsulfonyl) imide (LiTFSI), lithium bis (pentafluoroethyl sulfonate) imide (LiBETI), lithium bis (fluoromalonic acid) borate (LiBFMB), and lithium difluorobis (oxalato) phosphate and lithium 4, 5-dicyano-2- (trifluoromethyl) imidazole (LiTDI).
In some embodiments, the lithium salt is present in an amount of 0.05% to 20% by mass based on the mass of the electrolyte. In some embodiments, the lithium salt is 0.05%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20% or any value therebetween by mass. In some embodiments, the lithium salt is present in an amount of 1% to 15% by mass.
In some embodiments, the electrolyte further comprises a solvent comprising 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 is present in an amount of 0.05% to 80% by mass based on the mass of the electrolyte. In some embodiments, the solvent is 0.05%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% or any value therebetween by mass. In some embodiments, the solvent is present in an amount of 20% to 70% by mass.
In some embodiments, the anode active material layer includes an anode active material. The negative electrode active material includes a silicon-based material, or a mixture of a silicon-based material and at least one material selected from a carbon-based material, a tin-based material, a phosphorus-based material, and metallic lithium.
In some embodiments, 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 carbon-based material comprises at least one of graphite, soft carbon, hard carbon, carbon nanotubes, and graphene. In some embodiments, the tin-based material includes at least one of tin, tin oxide, and tin alloy. In some embodiments, the phosphorus-based material includes phosphorus and/or a phosphorus complex.
In some embodiments, the mass percentage z% of the silicon-based material, based on the mass of the negative electrode active material, satisfies: z is more than or equal to 10 and less than or equal to 100. In some embodiments, z is 11, 13, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or any value therebetween.
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 tab 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 positive electrode sheet includes a positive electrode active material layer including a positive electrode active material including a lithium nickel transition metal oxide.
In some embodiments, the lithium nickel transition metal oxide comprises LiNi x M 1-x O 2 At least one of the materials, M is selected from at least one of cobalt, manganese, iron, chromium, titanium, zinc, vanadium, aluminum, zirconium and cerium, and x is more than or equal to 0.7 and less than or equal to 0.95. It is understood that all transition metal elements in the positive electrode active material include a transition element nickel (Ni) and other transition elements M (at least one selected from cobalt, manganese, iron, chromium, titanium, zinc, vanadium, aluminum, zirconium, and cerium). The mole percentage content of nickel element is a ratio based on the total mole amount of all transition metal elements (including transition element Ni and other transition elements M) in the positive electrode active material.
In some embodiments, x is 0.7, 0.72, 0.74, 0.76, 0.78, 0.8, 0.82, 0.84, 0.86, 0.88, 0.9, 0.92, 0.94, 0.96, 0.98, 1, or any value therebetween.
In some embodiments, the positive electrode active material includes at least one of lithium nickel oxide, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese oxide, lithium nickel manganese cobalt magnesium oxide, and lithium nickel manganese oxide.
In some embodiments, the positive electrode active material layer further includes a binder, and optionally includes a conductive material. 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 material 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 tab 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 formed by forming a metal material (copper, copper alloy, nickel alloy, titanium alloy, silver alloy, or the like) on a polymer substrate.
In some embodiments, a separator is provided between the positive and negative electrode sheets 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 40 ℃ to 50 ℃, e.g., 41 ℃, 42 ℃, 43 ℃, 44 ℃, 45 ℃, 46 ℃, 47 ℃, 48 ℃, or 49 ℃.
In some embodiments, the forming comprises: charging to 4.25V 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 210kgf, standing for 60 min, then charging to 4.25V 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 application also provides a device comprising the secondary battery.
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 and comparative examples
Example 1
The preparation steps of the positive pole piece are as follows: the positive electrode active material LiNi 0.7 Co 0.15 Mn 0.15 O 2 CNT (conductive agent carbon nanotube)/acetylene blackPolyvinylidene fluoride PVDF as binder in weight proportion 0.7 Co 0.15 Mn 0.15 O 2 : CNT/acetylene black: pvdf=95: (2.0/1.0): 2, in N-methyl pyrrolidone NMP, fully homogenizing, coating on an aluminum current collector with the thickness of 12 mu m, and then drying, rolling, hot-pressing and the like to obtain the positive electrode plate.
The preparation steps of the negative electrode plate are as follows: the negative electrode active material silicon oxide (SiOx, x is more than or equal to 0.5 and less than or equal to 1.5) -graphite compound (Si/C=14:86), conductive agent acetylene black, binder styrene-butadiene rubber SBR, thickener sodium carboxymethyl cellulose CMCNa and polyacrylic acid PAA are mixed according to the weight ratio of 95:2:1.5:1: and 0.5, adding the mixture into deionized water, fully homogenizing the mixture, coating the mixture on an 8 mu m thick copper current collector, and then drying, rolling, hot-pressing and the like to obtain the negative electrode plate.
Preparation of electrolyte: in an argon-filled glove box (H) 2 O＜0.1ppm，O 2 < 0.1 ppm), lithium salt LiPF 6 Fully dissolving in a mixed solution of EC/DEC/EMC (ethylene carbonate/diethyl carbonate/methyl ethyl carbonate) =25/20/55 to prepare a solution of 1 mol/L, then adding 0.3% of boron-containing additive lithium bis (oxalato) borate (LiBOB) and 0.5% of phosphorus-containing additive tris (trimethylsilyl) phosphate (TMSP), and stirring uniformly to obtain an electrolyte.
Isolation film: adopts a PP/PE/PP (polypropylene/polyethylene/polypropylene) three-layer composite isolating film.
Preparation of lithium ion secondary battery: the positive electrode plate, the isolating film (PP/PE/PP three-layer composite film) and the negative electrode plate are sequentially overlapped layer by layer, the isolating film is positioned between the positive electrode plate and the negative electrode plate, a bare cell is obtained by winding, the bare cell is placed in a punched aluminum plastic film soft package shell, the prepared 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 forming condition is that the temperature is 45 ℃, the pressure is 210kgf, the current is charged to 4.25V for 60 minutes, then the current is charged to 4.25V at 0.1C, then the current is discharged to 3.0V at 0.2C, and the process is repeated for three times), and the conventional capacity division is carried out after secondary sealing.
Examples 2 to 12 and comparative examples 1 to 8
Examples 2 to 12 and comparative examples 1 to 8 were carried out by adjusting the content of nickel element in the positive electrode active material to the transition metal element, the kind and content of additives in the electrolyte, the formation conditions, and the like on the basis of example 1, and specific adjustment measures and detailed data are shown in table 1.
TABLE 1
Test method
1. Cycle performance test
The prepared lithium ion secondary battery was charged to 4.2V at a constant current of 1C rate at 25 ℃, and then charged at a constant voltage until the current was less than 0.05C. After standing for 5 minutes, the initial discharge capacity was again recorded by discharging to 2.5V at 1C magnification. The lithium ion secondary battery was charged and discharged 500 times by the above method, and the discharge capacity of each time was recorded. Capacity retention rate of the lithium ion secondary battery at 25 ℃ for 500 cycles = 500 th discharge capacity/initial discharge capacity x 100%.
2. X-ray photoelectron spectrometer (XPS) test
Discharging the lithium ion battery to 2.5V under the current of 0.1C, and detaching the lithium ion battery in a glove box filled with argon to obtain the electrode plate. Cutting the obtained electrode plate into a test sample with the size of 8 mm multiplied by 8 mm, soaking and cleaning for half an hour by using a low-boiling point dimethyl carbonate DMC solvent, sticking the test sample on a sample table of XPS after the test sample is completely dried, enabling the surface of 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 atoms of each component were calculated using single crystal spectral alkα radiation, using 1000X 1750 μm ellipsoids output of 10 KV and 22 mA for the X-ray points, selecting data for sputter etching 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. For example, the mass percentage of boron element in the CEI film of the positive electrode sheet and the mass percentage of phosphorus element in the CEI film of the positive electrode sheet can be obtained through the testing method.
3. Inductively coupled plasma emission spectrometer (ICP) testing
The content of the transition metal (e.g., nickel Ni element) on the surface of the anode active material layer may be quantitatively analyzed by ICP. The method comprises the following steps: disassembling the battery after 500 circles of circulation in a protective atmosphere, taking out the negative electrode plate, cleaning and soaking the disassembled negative electrode plate by DMC, removing residual electrolyte on the surface of the electrode plate, and eliminating the influence of the electrolyte. And after the DMC solvent volatilizes, collecting negative electrode plate powder for later use in subsequent ICP test. Specifically, about 0.05g (accurate to 0.00001 g) of the sample is weighed into a 50mL beaker, 8.0mL of 1+1 hydrochloric acid is added, the mixture is heated and dissolved at a low temperature on an electric furnace, 5 drops of hydrogen peroxide and a small amount of water are added after the sample is basically dissolved, and the mixture is taken down and cooled after being heated until the solution does not generate small bubbles. Transfer to volume in 100mL volumetric flask while blank experiments were performed. The content of the transition metal cobalt element on the surface of the anode active material layer can be obtained by the test method, and the unit is ppm. And carrying out ICP test on the battery cells of the 500-turn front Fail by taking the battery cells of the corresponding turns when the capacity of the battery cells is attenuated to be below 60%.
4. Impedance testing
The lithium ion battery before the cycle capacity retention rate test is discharged to 2.5V at the constant current of 1C at the temperature of 25+/-2 ℃, then is charged to 4.25V at the constant current of 0.5C, is charged to 0.05C at the constant voltage of 4.25V, then is discharged to 50% SOC at the constant current of 1C, is kept stand for 60min, the voltage U1 after the standing is finished is recorded, the constant current of 2℃ is discharged for 10s, the voltage U2 after the discharging is recorded, the current of 2℃ is recorded as I, and the standing is carried out for 60min. The discharge DCR (impedance) of the battery at 50% soc was calculated as dcr= (U1-U2)/I.
Test results
TABLE 2
As is clear from examples 1 to 12 and comparative examples 1 to 8, when the molar percentage content of nickel element in the positive electrode active material to the transition metal element, the content of boron element in the CEI film, and the content of phosphorus element in the CEI film satisfy the preset relationship, the capacity retention rate of the battery at 25 ℃ for 500 times is high, and the cycle performance is good; in addition, the nickel element content of the negative electrode plate is low, which shows that the dissolution of transition metal ions such as nickel (Ni) in the positive electrode plate is effectively inhibited, so that the problem of short circuit caused by embedding the dissolved transition metal ions into the negative electrode plate is solved, the damage of the transition metal ions to the negative electrode plate is inhibited, the stability of the negative electrode plate is improved, and the capacity retention rate of the secondary battery is improved; in addition, through the control, the impedance of the battery is obviously reduced, and the battery power is improved.
As is clear from comparison between comparative examples 1 and 2, when the molar percentage content of nickel element in the positive electrode active material to the transition metal element, the boron element content in the CEI film, and the phosphorus element content in the CEI film do not satisfy the predetermined relationship, that is, are lower than the predetermined value, the capacity retention rate of the battery at 25 ℃ for 500 times is poor, the nickel element content of the negative electrode sheet is high, the transition metal ion such as nickel (Ni) in the positive electrode sheet is more eluted, the cycle performance is poor, the impedance of the battery is high, and the power of the battery is reduced. As is clear from comparison between comparative examples 3 and 4, when the percentage content of the boron-containing additive added is too high or too low, the content of boron element in the CEI film after formation is high or low, the molar percentage content of nickel element in the positive electrode active material to the transition metal element, the content of boron element in the CEI film, and the content of phosphorus element in the CEI film do not satisfy the preset relationship, the capacity retention rate of the battery is poor, the nickel element content of the negative electrode sheet is high, the cycle performance is poor, the impedance of the battery is high, and the battery power is reduced. As can be seen from comparison of comparative example 5, when the molar percentage content of nickel element in the positive electrode active material to the transition metal element, the boron element content in the CEI film, and the phosphorus element content in the CEI film do not meet the preset relationship, that is, are higher than the preset value, the battery capacity retention rate is poor, the nickel element content of the negative electrode sheet is significantly increased, the transition metal ions such as nickel (Ni) in the positive electrode sheet are more eluted, the cycle performance is poor, the impedance of the battery is also significantly increased, and the battery power is reduced. As can be seen from comparison of comparative example 6, when the molar percentage content of nickel element in the positive electrode active material to the transition metal element is too low, the molar percentage content of nickel element in the positive electrode active material to the transition metal element, the boron element content in the CEI film, and the phosphorus element content in the CEI film do not conform to the preset relationship after formation, the battery capacity retention rate is poor, the nickel element content of the negative electrode sheet is remarkably increased, the transition metal ions such as nickel (Ni) in the positive electrode sheet are more dissolved out, the cycle performance is poor, the impedance of the battery is also remarkably increased, and the battery power is reduced. As is clear from comparison between comparative example 7 and comparative example 8, when the percentage content of the added phosphorus-containing additive is too high or too low, the phosphorus element content in the CEI film after formation is high or low, the molar percentage content of the nickel element in the transition metal element in the positive electrode active material, the boron element content in the CEI film, and the phosphorus element content in the CEI film do not conform to the preset relationship, the capacity retention rate of the battery is poor, the nickel element content of the negative electrode sheet is significantly increased, the cycle performance is poor, the impedance of the battery is significantly increased, and the battery power is reduced.
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 (12)

1. The secondary battery is characterized by comprising a positive electrode plate, a negative electrode plate and electrolyte;
the electrolyte comprises a boron-containing additive and a phosphorus-containing additive;
the positive electrode plate 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, the positive electrode active material layer comprises a positive electrode active material, the positive electrode active material comprises lithium nickel transition metal oxide, and the nickel element in the positive electrode active material accounts for Y% of the transition metal element in mole percentage;
the method is characterized in that an X-ray photoelectron spectrometer is adopted to test the solid electrolyte interface film under the condition that the sputtering etching time is 0 second, wherein the mass percentage of boron element in the solid electrolyte interface film is X 1 % of, what is shownThe mass percentage of the phosphorus element in the solid electrolyte interface film is X 2 The%; wherein 0.7 is less than or equal to 0.02Y-0.5X 1 -0.5X 2 ≤1，0.4≤X 1 ≤1.2，0.6≤X 2 ≤1.2。
2. The secondary battery according to claim 1, wherein 0.8.ltoreq.0.02Y-0.5X 1 -0.5X 2 ≤0.9。
3. The secondary battery according to claim 1 or 2, wherein 70.ltoreq.y.ltoreq.95.
4. The secondary battery according to claim 3, wherein the secondary battery further satisfies at least one of the following conditions:
（a）80≤Y≤90；
（b）0.6≤X 1 ≤0.9；
（c）0.8≤X 2 ≤1。
5. the secondary battery according to claim 1 or 2, wherein the secondary battery further satisfies at least one of the following conditions:
(d) The boron-containing additive comprises an oxalic acid borate additive comprising at least one of the compounds represented by formula I and formula II:
a formula I; />A formula II;
wherein in formula I, A 1 + Selected from metal ions or organic cations; in the formula II, A 2 + Selected from metal ions or organic cations, R 1 、R 2 Each independently selected from substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkoxy, or halogen, wherein the substituted substitutionA group selected from halogen selected from fluorine, chlorine, bromine or iodine;
(e) The phosphorus-containing additive comprises at least one of compounds shown in formula III and formula IV:
formula III; />A formula IV;
Wherein in formula III and formula IV, R 3 、R 4 、R 5 、R 6 、R 7 、R 8 Each independently selected from substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkoxy, substituted or unsubstituted C3-C6 alkylsilyl, substituted or unsubstituted C2-C6 alkenyl, or substituted or unsubstituted C6-C12 aryl, wherein each of the substituted substituents is independently selected from halogen selected from fluorine, chlorine, bromine, or iodine.
6. The secondary battery according to claim 5, wherein the secondary battery further satisfies at least one of the following conditions:
(f) In formula I, the metal ion is selected from Li + 、Na + Or K + The organic cation is selected from ammonium ion, trimethylamine ion, pyridinium ion or imidazolium ion; in formula II, the metal ion is selected from Li + 、Na + Or K + The organic cation is selected from ammonium ion, trimethylamine ion, pyridinium ion or imidazolium ion, and the R 1 、R 2 Each independently selected from fluoro-substituted C1-C6 alkyl, fluoro-substituted C1-C6 alkoxy or fluoro;
(g) In the formula III and the formula IV, R 3 、R 4 、R 5 、R 6 、R 7 、R 8 Each independently selected from the group consisting of substituted or unsubstituted C1-C3 alkyl, substituted or unsubstituted C3-C6 alkylsilyl, substituted or unsubstituted C2-C3 alkenyl, and substituted or unsubstituted C6-C12 aryl, wherein the substituents are Each of the substituents of (2) is independently selected from fluorine.
7. The secondary battery according to claim 6, wherein the secondary battery further satisfies at least one of the following conditions:
(h) The boron-containing additive comprises at least one of lithium bisoxalato borate and lithium difluorooxalato borate;
(i) The phosphorus-containing additive comprises at least one of the following compounds:
8. the secondary battery according to claim 1 or 2, wherein the secondary battery further satisfies at least one of the following conditions:
(j) The mass percentage content of the boron-containing additive is 0.1-3% based on the mass of the electrolyte;
(k) The mass percentage of the phosphorus-containing additive is 0.1-3% based on the mass of the electrolyte.
9. The secondary battery according to claim 8, wherein the secondary battery further satisfies at least one of the following conditions:
(l) The mass percentage content of the boron-containing additive is 0.5-2% based on the mass of the electrolyte;
(m) the mass percent of the phosphorus-containing additive is 0.5% -2% based on the mass of the electrolyte.
10. The secondary battery according to claim 1 or 2, wherein the secondary battery further satisfies at least one of the following conditions:
(n) the electrolyte further comprises a first additive comprising at least one of a cyclic carbonate containing a carbon-carbon double bond, a nitrile compound, and a pyridinium propane sulfonate; the mass percentage content of the first additive is 0.05-10% based on the mass of the electrolyte;
(o) the lithium nickel transition metal oxide comprises LiNi x M 1-x O 2 At least one of the materials, M is selected from at least one of cobalt, manganese, iron, chromium, titanium, zinc, vanadium, aluminum, zirconium and cerium, and x is more than or equal to 0.7 and less than or equal to 0.95;
(p) the negative electrode tab comprises a negative electrode active material layer comprising a negative electrode active material; the negative electrode active material includes a silicon-based material, or a mixture of a silicon-based material and at least one material selected from a carbon-based material, a tin-based material, a phosphorus-based material, and metallic lithium; wherein the silicon-based material comprises at least one of silicon, a silicon alloy, a silicon oxygen compound, and a silicon carbon compound, the carbon-based material comprises at least one of graphite, soft carbon, hard carbon, carbon nanotubes, and graphene, the tin-based material comprises at least one of tin, tin oxide, and a tin alloy, and the phosphorus-based material comprises phosphorus and/or a phosphorus carbon composite.
11. The secondary battery according to claim 10, wherein the secondary battery further satisfies at least one of the following conditions:
(q) the positive electrode active material includes at least one of lithium nickel oxide, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese oxide, lithium nickel manganese cobalt magnesium oxide, and lithium nickel manganese oxide;
(r) based on the mass of the anode active material, the mass content z% of the silicon-based material satisfies: z is more than or equal to 10 and less than or equal to 100.
12. An apparatus comprising the secondary battery according to any one of claims 1 to 11.
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