WO2018137169A1 - Lithium ion battery and preparation method therefor - Google Patents

Lithium ion battery and preparation method therefor Download PDF

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Publication number
WO2018137169A1
WO2018137169A1 PCT/CN2017/072568 CN2017072568W WO2018137169A1 WO 2018137169 A1 WO2018137169 A1 WO 2018137169A1 CN 2017072568 W CN2017072568 W CN 2017072568W WO 2018137169 A1 WO2018137169 A1 WO 2018137169A1
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lithium
positive electrode
ion battery
lithium ion
electrolyte
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PCT/CN2017/072568
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French (fr)
Chinese (zh)
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张晶晶
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罗伯特·博世有限公司
张晶晶
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Application filed by 罗伯特·博世有限公司, 张晶晶 filed Critical 罗伯特·博世有限公司
Priority to PCT/CN2017/072568 priority Critical patent/WO2018137169A1/en
Priority to CN201780075404.9A priority patent/CN110036523A/en
Priority to KR1020197021700A priority patent/KR20190103232A/en
Priority to DE112017006921.1T priority patent/DE112017006921T5/en
Publication of WO2018137169A1 publication Critical patent/WO2018137169A1/en

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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
    • 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
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M10/05—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
    • H01M10/058—Construction or manufacture
    • 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
    • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • 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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H01M2300/0028—Organic electrolyte characterised by the solvent
    • H01M2300/0037—Mixture of solvents
    • 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
    • H01M4/04—Processes of manufacture in general
    • H01M4/0438—Processes of manufacture in general by electrochemical processing
    • H01M4/044—Activating, forming or electrochemical attack of the supporting material
    • H01M4/0445—Forming after manufacture of the electrode, e.g. first charge, cycling
    • H01M4/0447—Forming after manufacture of the electrode, e.g. first charge, cycling of complete cells or cells stacks
    • 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
    • H01M4/04—Processes of manufacture in general
    • H01M4/0438—Processes of manufacture in general by electrochemical processing
    • H01M4/0459—Electrochemical doping, intercalation, occlusion or alloying
    • 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
    • H01M4/139—Processes of manufacture
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • 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
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present disclosure provides a novel lithium ion battery comprising a positive electrode, a negative electrode and an electrolyte, wherein the positive electrode comprises a positive active material and a pre-lithiation lithium source selected from the group consisting of LiVO 3 , LiV 3 O 8. Li 3 VO 4 , Li 2 C 2 and any combination thereof, preferably Li 2 C 2 .
  • the invention also provides a preparation method of the lithium ion battery.
  • lithium ion batteries have been widely used in energy storage systems and electronic devices.
  • lithium ions migrate from the positive electrode to the negative electrode during charging.
  • a lithium-containing positive electrode material for example, LiCoO 2 or LiNiO 2
  • a negative electrode material for example, graphite
  • an electrolytic solution lithium ions migrate from the positive electrode to the negative electrode during charging.
  • lithium ions inevitably continue to react with the electrolyte, thereby undesirably consuming lithium and forming a solid electrolyte interface (SEI) on the anode.
  • SEI solid electrolyte interface
  • the consumed lithium does not return to the positive electrode, causing rapid decay of the capacity of the lithium ion battery.
  • the inventors of the present invention have developed a novel lithium ion battery comprising a positive electrode, a negative electrode and an electrolyte, wherein the positive electrode comprises a positive electrode active material and a lithium pre-lithiation source selected from the group consisting of LiVO 3 , LiV 3 O 8 , Li 3 VO 4 , Li 2 C 2 and any combination thereof, preferably Li 2 C 2 .
  • the present disclosure also provides a method of preparing the lithium ion battery, the method comprising the steps of:
  • a positive electrode comprising a positive active material and a lithium pre-lithiation source selected from the group consisting of LiVO 3 , LiV 3 O 8 , Li 3 VO 4 , Li 2 C 2 and any combination thereof, preferably Li 2 C 2 ;
  • the present disclosure also provides a lithium ion battery comprising a positive electrode, a negative electrode and an electrolyte, wherein the electrolyte comprises a lithium salt, a non-aqueous solvent, and a pre-lithiation lithium source selected from the group consisting of LiVO 3 , LiV 3 O 8 Li 3 VO 4 , Li 2 C 2 and any combination thereof, preferably Li 2 C 2 ;
  • the electrolyte further comprises a boron based anion acceptor.
  • the present disclosure also provides a method of preparing the lithium ion battery, the method comprising the steps of:
  • the electrolyte comprising a lithium salt, a non-aqueous solvent and a pre-selected lithiated lithium source: LiVO 3, LiV 3 O 8 , Li 3 VO 4, Li 2 C 2 , and any combination thereof , preferably Li 2 C 2 ;
  • LiVO 3 , LiV 3 O 8 , Li 3 VO 4 and/or Li 2 C 2 , especially Li 2 C 2 can be advantageously used in the positive electrode and/or electrolysis of lithium ion batteries.
  • it serves as a lithium source for the pre-lithiated negative electrode.
  • Pre-lithiation of the negative electrode of a lithium ion battery by employing a particular pre-lithiation lithium source of the present invention can compensate for capacity degradation and significantly improve battery performance (e.g., irreversible capacity and cycle stability).
  • lithium powder Since lithium powder has high activity against moisture in the air, hydrogen gas is released during the reaction, and therefore, there is a risk of explosion when lithium powder is used in the battery.
  • the particular pre-lithiation lithium source employed in the present invention is relatively stable to moisture in the air.
  • Li 2 C 2 when Li 2 C 2 is used as the lithium source of pre-lithiation, even if Li 2 C 2 reacts with moisture, it is considered that Li 2 C 2 is composed only of elemental lithium and carbon, and the reaction product does not contain undesired The impurities are less likely to cause side reactions due to the introduced impurities, thereby impairing battery performance. Moreover, if Li 2 C 2 reacts with moisture in the air and does not blast due to gas generation, the preparation of the battery does not require a harsh vacuum environment, which greatly improves production safety and reduces production costs.
  • a specific pre-lithiation lithium source can be supplied to the positive electrode or the electrolyte. Since the specific pre-lithiation lithium source used in the present invention is compatible with the positive electrode or other components contained in the electrolyte, it is not necessary to change the composition of the positive electrode or the electrolyte. However, if the lithium powder is directly supplied to the negative electrode, it is necessary to adjust the solvent and the binder contained in the negative electrode accordingly.
  • Figure 1 is a schematic comparison of the charge/discharge performance of a comparative example with a battery prepared in accordance with an embodiment of the present invention.
  • Figure 2 is a schematic comparison of the cycling performance of a comparative example with a battery prepared in accordance with an embodiment of the present invention.
  • Ranges of values recited herein are intended to include the endpoints of the ranges, and all values and all sub-ranges within the range.
  • lithium ion battery is used interchangeably with the term “battery.”
  • the term “comprising” or “including” as used herein means that other components or other steps that do not affect the final effect may also be included or included.
  • the term “comprising” or “including” encompasses the "consisting of” and “consisting primarily of”.
  • the methods and products of the present disclosure may comprise or include the necessary technical features and/or defined features described herein to And any other and/or optionally present ingredients, components, steps or defined features described herein.
  • the methods and products of the present disclosure may also be constructed from the essential technical features and/or defined features described herein, or consist essentially of the essential technical features and/or defined features described herein.
  • positive electrode composition or "negative electrode composition” means a composition for forming a positive electrode slurry or a negative electrode slurry.
  • the positive electrode slurry or the negative electrode slurry may then be applied to a corresponding current collector, and after drying, a positive electrode or a negative electrode may be formed.
  • a lithium ion battery comprising a positive electrode, a negative electrode, and an electrolyte, wherein the positive electrode comprises a positive active material and a pre-lithiation lithium source selected from the group consisting of LiVO 3 , LiV 3 O 8 , Li 3 VO 4 , Li 2 C 2 and any combination thereof, preferably Li 2 C 2 .
  • a lithium ion battery comprising a positive electrode, a negative electrode, and an electrolyte, wherein the electrolyte comprises a lithium salt, a non-aqueous solvent, and a pre-lithiation lithium source selected from the group consisting of LiVO 3 , LiV 3 O 8 , Li 3 VO 4 , Li 2 C 2 and any combination thereof, preferably Li 2 C 2 ;
  • the electrolyte further comprises a boron based anion acceptor.
  • the lithium ion battery is pre-lithiated or not pre-lithiated.
  • the Li 2 C 2 content is from greater than 0 to about 20% by weight, preferably from greater than 0 to less than 20% by weight, more preferably from about 0.01% to about 5% by weight, based on the total dry weight of the positive electrode composition, Still more preferably from about 0.01% by weight to about 1% by weight.
  • a method of making a lithium ion battery in accordance with the present disclosure comprising the steps of:
  • a positive electrode comprising a positive active material and a lithium pre-lithiation source selected from the group consisting of LiVO 3 , LiV 3 O 8 , Li 3 VO 4 , Li 2 C 2 and any combination thereof, preferably Li 2 C 2 ;
  • a method of making a lithium ion battery in accordance with the present disclosure comprising the steps of:
  • an electrolyte comprising a lithium salt, a non-aqueous solvent, and a pre-lithiation lithium source selected from the group consisting of LiVO 3 , LiV 3 O 8 , Li 3 VO 4 , Li 2 C 2 , and any combination thereof , preferably Li 2 C 2 ;
  • the content of Li 2 C 2 in the pre-lithiated or unpre-lithiated cell is greater than 0 to about 20% by weight, preferably greater than 0 to less than 20, based on the total dry weight of the positive electrode composition. % by weight, more preferably from about 0.01% to about 5% by weight, still more preferably from about 0.01% to about 1% by weight.
  • the inventors of the present invention have surprisingly found that by providing the lithium ion battery of the present disclosure, on the one hand, the SEI can be stabilized, the capacity attenuation can be compensated, and the battery performance (e.g., irreversible capacity and cycle stability) can be significantly improved. On the other hand, undesired lithium dendrites can be avoided.
  • the particular pre-lithiation lithium source employed in the present invention is relatively stable to moisture in the air.
  • Li 2 C 2 when Li 2 C 2 is used as the lithium source of pre-lithiation, even if Li 2 C 2 reacts with moisture, it is considered that Li 2 C 2 is composed only of elemental lithium and carbon, and the reaction product does not contain undesired
  • the impurities are less likely to cause side reactions due to the introduced impurities, thereby impairing battery performance.
  • Li 2 C 2 reacts with moisture in the air and does not blast due to gas generation, the preparation of the battery does not require a harsh vacuum environment, which greatly improves production safety and reduces production costs.
  • a specific pre-lithiation lithium source can be supplied to the positive electrode or the electrolyte. Since the specific pre-lithiation lithium source used in the present invention is compatible with the positive electrode or other components contained in the electrolyte, it is not necessary to change the composition of the positive electrode or the electrolyte. However, if lithium is to be When the powder is directly supplied to the negative electrode, it is necessary to adjust the solvent and the binder contained in the negative electrode accordingly.
  • a positive electrode including a positive electrode active material and a pre-lithiation lithium source (particularly Li 2 C 2 )
  • a positive electrode active material and a pre-lithium lithium source may be used to form a positive electrode slurry, and then the positive electrode slurry is used.
  • a pre-lithiation lithium source (particularly Li 2 C 2 ) may be mixed with other components of the positive electrode composition to form a positive electrode slurry, wherein other components of the positive electrode composition include, for example, a positive active material, a carbon material , binders, solvents and/or additives optionally present.
  • the positive electrode slurry can be applied to the positive electrode current collector by, for example, coating, thereby forming a positive electrode including a pre-lithiation lithium source.
  • a pre-lithiation lithium source can be easily introduced into the positive electrode.
  • the introduction step of the pre-lithium lithiation source is integrated with the addition step of the other components of the positive electrode (integrated), no additional separate addition steps are required, and no special operating conditions are required, which means considerable cost for industrial production. Reduced and labor saved.
  • a positive electrode including a positive electrode active material and a pre-lithiation lithium source (particularly Li 2 C 2 )
  • a positive electrode active material may also be applied to the positive electrode current collector to form an active material layer, and then the pre-lithium may be used.
  • a lithium source (particularly Li 2 C 2 ) is applied to the active material layer to form a pre-lithiated lithium source layer. Providing a pre-lithiation lithium source in this manner is also easy to implement.
  • a lithium ion battery according to the present disclosure can be used in an energy storage system and an electronic device.
  • lithium ions are released from a particular pre-lithiation lithium source of the positive or electrolyte during the first few (eg, 1-5) charging cycles.
  • the released lithium ions are inserted into the negative electrode and stored in the negative electrode, thereby pre-lithiation of the negative electrode. Therefore, the first several charging processes of pre-lithiation of the negative electrode are also referred to as "formation” or “formation charge”.
  • lithium stored in the negative electrode during the formation process can participate in lithium ion migration, compensate for lithium lost due to formation of the SEI layer, stabilize the SEI layer, and reduce capacity degradation.
  • the negative electrode may be partially pre-lithiated to compensate for lithium lost due to formation of SEI and to retain the desired lithium migration between the positive and negative electrodes.
  • the formation may be performed over a range of voltages, also referred to as the "cutoff voltage" range.
  • the upper limit of the cutoff voltage is no less than about 3.8V but no greater than about 5V, preferably no less than about 4.2V but no greater than about 5V.
  • the upper limit of the cutoff voltage depends on the positive active material contained in the lithium ion battery.
  • the positive electrode active material will be described in detail below.
  • the upper limit of the cutoff voltage during the formation is not lower than about 4.2 V but not higher than about 5 V.
  • the upper limit of the cutoff voltage during the formation process is not less than about 4.35 V but not Above about 5V.
  • the lithium ion source can sufficiently release lithium ions, and on the other hand, the positive electrode is not seriously damaged.
  • the irreversible capacity (unit: mAh/cm 2 ) of the negative electrode usable for intercalating lithium is irreversible of the positive electrode
  • the capacity (unit: mAh/cm 2 ) is from about 1 time to about 1.4 times, preferably from about 1 time to about 1.2 times, more preferably from about 1 time to about 1.1 times.
  • the ratio of the irreversible capacity of the negative electrode to the irreversible capacity of the positive electrode is one. However, considering that there is inevitably an operational error in the process of preparing the battery, the ratio may be greater than one. If the ratio of the irreversible capacity of the negative electrode to the irreversible capacity of the positive electrode is from 1 to about 1.4, it is possible to avoid formation of lithium dendrites around the negative electrode without excessively consuming the irreversible capacity of the negative electrode.
  • the lithium ion battery can be pre-lithiated or not pre-lithiated.
  • the positive electrode composition may comprise a pre-lithiation lithium source selected from the group consisting of LiVO 3 , LiV 3 O 8 , Li 3 VO 4 , Li 2 C 2 , and any combination thereof.
  • the pre-lithiation lithium source is used to pre-lithiation the negative electrode.
  • the Li 2 C 2 content is from greater than 0 to about 20% by weight, preferably from greater than 0 to less than 20% by weight, more preferably from about 0.01% to about 5% by weight, based on the total dry weight of the positive electrode composition, Still more preferably from about 0.01% by weight to about 1% by weight. If the content of the pre-lithiation lithium source falls within the above range, on the one hand, lithium which is lost due to the formation of SEI can be sufficiently compensated, and on the other hand, undesired lithium dendrites can be avoided.
  • the positive electrode composition may contain traces of a source of pre-lithiation lithium.
  • the content of Li 2 C 2 is from about 0.01% to about 1 wt%.
  • Li 2 C 2 can be produced by a known method using lithium and carbon as raw materials.
  • Jiangtao He et al. "Preparation and phase stability of nanocrystalline Li 2 C 2 alloy", Materials Letters 94 (2013), pages 176-178, discloses a process for preparing Li 2 C 2 . This document is incorporated herein by reference in its entirety.
  • the particle size of the pre-lithiation lithium source is not particularly limited, and nanometer-sized (less than 1 micrometer) or micrometer-sized (greater than 1 micrometer but less than 1 millimeter) particle size can be used in the present disclosure; nanoscale is preferred.
  • the positive electrode in addition to the pre-lithiation lithium source, may further comprise a lithium-based active material.
  • the positive active material is a material that can reversibly deintercalate and intercalate lithium ions in a charge/discharge cycle. In the discharge cycle, lithium ions obtained from the positive electrode active material can be returned from the negative electrode to the positive electrode to form the positive electrode active material again.
  • the prelithium lithium source may be referred to as an "extra lithium source” or an “additional lithium source” relative to the positive active material used as the base lithium source.
  • the positive electrode active material is not particularly limited, and a positive electrode active material which is commonly used in a lithium ion battery can be used in the present disclosure.
  • the positive active material may be different from the pre-lithiation lithium source.
  • the positive active material may be selected from the group consisting of lithium-metal oxides, lithium-metal phosphates, lithium-metal silicates, sulfides, and any combination thereof, preferably lithium-transition metal composite oxides, lithium-transitions Metal phosphates, lithium-metal silicates, metal sulfides, and any combination thereof.
  • the lithium-transition metal phosphate can be selected from the group consisting of lithium iron phosphate, lithium manganese phosphate, lithium manganese phosphate, and any combination thereof.
  • the lithium-transition metal composite oxide may be selected from the group consisting of lithium nickel oxide, lithium cobalt oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (NCM).
  • NCM lithium nickel cobalt aluminum oxide
  • the metal sulfide can be iron sulfide.
  • the positive electrode composition may further contain a carbon material in addition to the pre-lithiation lithium source and the positive electrode active material.
  • Carbon material refers to a material containing carbon.
  • a carbon material can be used to improve the conductivity and/or the fraction of the battery positive electrode composition. Scattered.
  • the carbon material is not particularly limited, and a carbon material commonly used for a lithium ion battery can be used in the present disclosure.
  • the carbon material may be selected from the group consisting of carbon black, superconducting carbon black (eg, Super P from Timcal Corporation), acetylene black, ketjen black, graphite, graphene, carbon nanotubes, carbon fiber, vapor grown Carbon fiber and combinations thereof.
  • a mixture of two or more carbon materials may be included in the positive electrode composition.
  • the positive electrode composition may simultaneously contain two or more carbon materials having different particle diameters, for example, a carbon material having a particle diameter of not less than 1 ⁇ m, and the same or different kinds of carbon having a particle diameter of less than 1 ⁇ m. material.
  • the positive electrode composition may further include a binder in addition to the pre-lithiation lithium source and the positive electrode active material.
  • the binder may bond the components of the cathode composition together and adhere the cathode composition to the cathode current collector.
  • the binder helps the positive electrode maintain good stability and integrity when repeated charge/discharge cycles cause volume changes, thereby improving the electrochemical performance (including cycling performance and rate performance) of the final cell.
  • the binder can be polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), sodium carboxymethylcellulose (CMC), preferably PVDF.
  • the positive electrode composition may further comprise a solvent.
  • the solvent can be used to dissolve other components in the positive electrode composition to provide a positive electrode slurry. Then, the obtained positive electrode slurry can be applied to the positive electrode current collector and dried to obtain a positive electrode.
  • the solvent contained in the positive electrode composition is not particularly limited, and a solvent commonly used in a lithium ion battery can be used in the present disclosure.
  • the solvent in the positive electrode composition may be N-methyl-2-pyrrolidone (NMP).
  • the positive electrode composition may include a pre-lithiation lithium source, a positive electrode active material, a carbon material, a binder, and a solvent, wherein the pre-lithium lithiate is selected from the group consisting of LiVO 3 , LiV 3 O 8 , and Li 3 VO 4 . Li 2 C 2 and any combination thereof. Further, the positive electrode composition may also optionally contain other additives commonly used in lithium ion batteries as long as these additives do not adversely impair the desired properties of the battery.
  • cathode current collector there is no particular limitation on the cathode current collector.
  • aluminum foil can be used as Positive current collector.
  • the anode composition may include a cathode active material.
  • the negative electrode active material is not particularly limited, and a negative electrode active material which is commonly used in a lithium ion battery can be used in the present disclosure.
  • the negative active material may be selected from the group consisting of silicon-based active materials, carbon-based active materials, and any combination thereof.
  • Silicon-based active material refers to an active material containing silicon. Suitable silicon-based active materials can include, but are not limited to, silicon, silicon alloys, silicon oxides, silicon/carbon composites, and silicon oxide/carbon composites, and any combination thereof.
  • the silicon alloy may comprise silicon and one or more metals selected from the group consisting of titanium, tin, aluminum, lanthanum, cerium, arsenic, antimony, and lead.
  • the silicon oxide can be a mixture of two or more oxides of silicon, for example, the silicon oxide can be represented by SiO x with an average value of x of from about 0.5 to about 2.
  • the carbon-based active material in the negative electrode may be the same as or different from the carbon material contained in the positive electrode.
  • suitable carbon-based active materials may include, but are not limited to, graphite, graphene, hard carbon, carbon black, and carbon nanotubes.
  • the negative electrode composition may further contain a carbon material, a binder, and/or a solvent.
  • the carbon material, binder, and/or solvent in the negative electrode may be the same as or different from the carbon material, binder, and/or solvent contained in the positive electrode, respectively.
  • the negative electrode composition may also optionally contain other additives commonly used in lithium ion batteries as long as these additives do not adversely impair the desired properties of the battery.
  • anode current collector there is no particular limitation on the anode current collector.
  • a nickel foil, a nickel mesh, a copper foil, or a copper mesh can be used as the negative current collector.
  • a lithium ion battery may contain an electrolyte.
  • the electrolyte may comprise a lithium salt and a non-aqueous solvent.
  • the nonaqueous solvent may be different from or not containing water, and may be an inorganic solvent or an organic solvent.
  • the lithium salt and the nonaqueous solvent are not particularly limited, and those lithium salts and nonaqueous solvents known to be usable for lithium ion batteries can be used in the present disclosure.
  • the lithium salt in the electrolyte can be different from the positive active material and the pre-lithiation lithium source.
  • the lithium salt may include, but is not limited to, lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium arsenate (LiAsO 4 ), LiSbO 4 , lithium perchlorate (LiClO 4 ), LiAlO 4 .
  • LiPF 6 lithium hexafluorophosphate
  • LiBF 4 lithium tetrafluoroborate
  • LiAsO 4 lithium arsenate
  • LiSbO 4 Li perchlorate
  • LiClO 4 LiAlO 4
  • LiGaO 4 lithium bis(oxalate)borate
  • LiBOB lithium bis(oxalate)borate
  • the non-aqueous solvent may be a non-fluorinated carbonate (hereinafter referred to as "carbonate") and/or a fluorinated carbonate.
  • carbonates include, but are not limited to, cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC); linear carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), ethyl methyl carbonate (EMC), methylpropyl carbonate (MPC) and ethylene propyl carbonate (EPC); and any of the above carbonates combination.
  • the fluorinated carbonate may be a fluorinated derivative of the above carbonates, such as fluoroethylene carbonate (FEC), difluoroethylene carbonate, and dimethyl difluorocarbonate (DFDMC). ).
  • the electrolyte may also contain a boron-based anion acceptor (ie, a boron-containing material that can accept anions).
  • a boron-based anion acceptor ie, a boron-containing material that can accept anions.
  • the boron-based anion acceptor is not particularly limited, and borane, borate ester and borate salt can be used as long as they have a Lewis acid center on the boron atom and can be combined with a pre-lithiation lithium source having a Lewis base center ( For example, Li 2 C 2 ) forms a complex.
  • the solubility of the pre-lithiation lithium source (for example, Li 2 C 2 ) in the electrolyte can be increased, and the power of the prelithiation lithium source to deintercalate lithium can be improved.
  • the electrolyte contains lithium salts is unstable to heat (e.g., LiPF 6)
  • a borane, a borate or borate anion can stabilize (e.g., PF 6 5-), and reduce the decomposition of the lithium salt.
  • the decomposition of the lithium salt causes capacity decay and increases resistance in the charge/discharge cycle.
  • a borane represented by the formula (fluoroalkyl-O) 3 -B a borane represented by the formula (fluoroaryl-O) 3 -B, and a formula (fluoroaryl) may be employed.
  • Borane represented by 3- B see HS Lee et al, J. Electochem. Soc., 145 (1998), pp. 2813-2818, which is incorporated herein by reference in its entirety.
  • Exemplary borate ester may include, but are not limited to, borate, tri (2H- hexafluoroisopropyl yl) ester (THFPB, [(CF 3) 2 CHO] 3 B) , and tri (2,4-difluoro-B ()) ester (F 2 C 6 H 3 O) 3 B.
  • Exemplary boranes can include, but are not limited to, tris(pentafluorophenyl)borane (TPFPB, (C 6 F 5 ) 3 B).
  • R is a fluorine-containing moiety.
  • oxalate boron oxalates may include, but are not limited to, pentafluorophenylboronoxalate (PFPBO).
  • Lithium bis(oxalato)borate represented by the following formula may also be used as a boron-based anion acceptor in the electrolyte:
  • lithium oxaltodifluoroborate (chemical formula LiBF 2 C 2 O 4 , abbreviated as LiODFB) described in US Pat. No. 10/625,686 can also be used as a boron-based anion acceptor in an electrolyte.
  • the oxalate boron oxalates (such as PFPBO), LiBOB, and LIODFB all contribute to the formation of a more stable SEI layer on the surface of the negative electrode, thereby reducing lithium consumption and improving battery performance.
  • NCM-111 lithium nickel cobalt manganese oxide, positive active material, D50: 12 ⁇ m, available from BASF.
  • Super P superconducting carbon black, carbon material, 40 nm, available from Timcal.
  • KS6L flake graphite, carbon material, about 6 ⁇ m, purchased from Timcal.
  • PVDF polyvinylidene fluoride, binder, available from Sovey.
  • NMP N-methyl-2-pyrrolidone, solvent, purchased from Sinopharm Chemical Reagent Co., Ltd.
  • Celgard 2325 polypropylene/polyethylene/polypropylene laminate film (PP/PE/PP film), separator, available from Celgard.
  • the obtained granules were placed in a cermet mold, and then the cermet mold containing the powder was immediately placed in a discharge plasma sintering furnace to be sintered again.
  • the external pressure was set to 300 MPa
  • the heating rate was set to 50 ° C / minute
  • the temperature was maintained for 2 minutes, thereby obtaining 72 mg of fine powder.
  • the obtained fine powder was subjected to XRD diffraction, and it was found that all the peaks were in agreement with the known Li 2 C 2 [JCPDS No. 70-3193].
  • NCM-111 938.6 mg NCM-111, 26.4 mg of the previously prepared Li 2 C 2 , 10 mg Super P, 5 mg KS6L, 20 mg PVDF were added to 450 mL. NMP. After stirring for 3 hours, the obtained uniformly dispersed slurry was applied onto an aluminum foil, followed by drying at 80 ° C for 6 hours in a vacuum. The coated aluminum foil was taken out from the glove box and punched into a plurality of 12 mm positive electrode sheets (abbreviated as NCM) using an EQ-T-06 battery pole piece punching machine (purchased from Shenzhen Weizhida Optoelectronics Technology Co., Ltd.). -Li 2 C 2 ).
  • NCM 12 mm positive electrode sheets
  • a coin battery (CR2016) was assembled using the positive electrode tab obtained above.
  • a pure lithium metal foil was used as the counter electrode.
  • 1 M LiPF 6 in FEC/EMC (3:7 by volume, a mixture of fluoroethylene carbonate (FEC) and ethyl methyl carbonate (EMC)) was used as the electrolyte.
  • Celgard 2325 (PP/PE/PP film) was used as the separator.
  • a positive electrode tab (abbreviated as NCM) was prepared in the same manner as in Example 1, except that Li 2 C 2 was not used, and 965 mg of NCM-111 was used instead of 938.6 mg of NCM-111.
  • Fig. 1 compares the charge/discharge performance of the battery prepared in Comparative Example 1 and Example 1 at the first charge/discharge cycle.
  • each battery was charged/discharged in a voltage range of 3-4.6 V (vs Li/Li + ).
  • the mass loading of NCM was about 10 mg/cm 2 .
  • the specific capacity is calculated based on the weight of the NCM.
  • the NCM-Li 2 C 2 positive electrode of Example 1 improved the charging capacity at the time of the first charge as compared with the NCM positive electrode of Comparative Example 1.
  • Figure 2 compares the cycle performance of Comparative Example 1 with the battery prepared in Example 1.
  • each battery is charged/discharged in a voltage range of 3-4.6 V (vs Li/Li + ); then, in the second to 80 charge/discharge cycles, 3
  • Each battery is charged/discharged within a voltage range of -4.3 V (vs Li/Li + ).
  • the mass loading of NCM was about 10 mg/cm 2 .
  • the specific capacity is calculated based on the weight of the NCM.
  • the NCM-Li 2 C 2 positive electrode in Example 1 showed improved capacity and stability as compared with the NCM positive electrode in Comparative Example 1.

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Abstract

Provided in the present invention is a novel lithium ion battery, said lithium ion battery comprising: a positive pole, a negative pole and an electrolyte, wherein the positive pole comprises a positive pole active material and a pre-lithiated lithium source selected from the following: LiVO3, LiV3O8, Li3VO4, Li2C2, and any combination thereof, preferably Li2C2. Further provided in the present invention is a preparation method for the lithium ion battery.

Description

锂离子电池及其制备方法Lithium ion battery and preparation method thereof 技术领域Technical field
本公开提供了一种新型的锂离子电池，所述锂离子电池包含正极、负极和电解液，其中所述正极包含正极活性材料和选自以下的预锂化锂源：LiVO3、LiV3O8、Li3VO4、Li2C2以及它们的任意组合，优选Li2C2。本发明还提供了所述锂离子电池的制备方法。The present disclosure provides a novel lithium ion battery comprising a positive electrode, a negative electrode and an electrolyte, wherein the positive electrode comprises a positive active material and a pre-lithiation lithium source selected from the group consisting of LiVO 3 , LiV 3 O 8. Li 3 VO 4 , Li 2 C 2 and any combination thereof, preferably Li 2 C 2 . The invention also provides a preparation method of the lithium ion battery.
背景技术Background technique
目前，锂离子电池已广泛用于储能系统和电子设备中。Currently, lithium ion batteries have been widely used in energy storage systems and electronic devices.
对于包含含锂的正极材料(例如LiCoO2或LiNiO2)、负极材料(例如石墨)、以及电解液的锂离子电池来说，在充电时锂离子从正极迁移到负极。但是，在迁移过程中，锂离子不可避免地持续与电解液反应，由此不期望地消耗锂并且在负极上形成固体电解质界面(SEI)。在随后的放电过程中，被消耗掉的锂不会回到正极，引起锂离子电池容量的快速衰减。For a lithium ion battery including a lithium-containing positive electrode material (for example, LiCoO 2 or LiNiO 2 ), a negative electrode material (for example, graphite), and an electrolytic solution, lithium ions migrate from the positive electrode to the negative electrode during charging. However, during the migration, lithium ions inevitably continue to react with the electrolyte, thereby undesirably consuming lithium and forming a solid electrolyte interface (SEI) on the anode. During the subsequent discharge process, the consumed lithium does not return to the positive electrode, causing rapid decay of the capacity of the lithium ion battery.
已经提出通过将额外的锂粉涂布在负极上，从而预锂化负极，补偿容量衰减。然后，将经预锂化的负极组装到锂离子电池中。但是，由于锂粉具有高活性，在预锂化之后的制备电池的过程中，需要严格控制操作环境的湿度，这会增加锂离子电池的生产成本。It has been proposed to pre-lithiate the negative electrode by coating additional lithium powder on the negative electrode to compensate for capacity decay. The prelithiated negative electrode is then assembled into a lithium ion battery. However, since lithium powder has high activity, in the process of preparing a battery after pre-lithiation, it is necessary to strictly control the humidity of the operating environment, which increases the production cost of the lithium ion battery.
因此，持续需要更具备吸引力和可靠性的锂离子电池及其制备方法。Therefore, there is a continuing need for more attractive and reliable lithium ion batteries and methods for their preparation.
发明内容Summary of the invention
经过深入研究，本发明的发明人已经开发了新型的锂离子电池，其包含正极、负极和电解液，其中所述正极包含正极活性材料和选自以下的预锂化锂源：LiVO3、LiV3O8、Li3VO4、Li2C2以及它们的任意组合，优选Li2C2。 After intensive research, the inventors of the present invention have developed a novel lithium ion battery comprising a positive electrode, a negative electrode and an electrolyte, wherein the positive electrode comprises a positive electrode active material and a lithium pre-lithiation source selected from the group consisting of LiVO 3 , LiV 3 O 8 , Li 3 VO 4 , Li 2 C 2 and any combination thereof, preferably Li 2 C 2 .
本公开还提供了制备所述锂离子电池的方法，所述方法包括以下步骤：The present disclosure also provides a method of preparing the lithium ion battery, the method comprising the steps of:
--提供正极，所述正极包含正极活性材料和选自以下的预锂化锂源：LiVO3、LiV3O8、Li3VO4、Li2C2以及它们的任意组合，优选Li2C2；Providing a positive electrode comprising a positive active material and a lithium pre-lithiation source selected from the group consisting of LiVO 3 , LiV 3 O 8 , Li 3 VO 4 , Li 2 C 2 and any combination thereof, preferably Li 2 C 2 ;
--将负极、电解液和所述正极组装成锂离子电池；以及任选地，- assembling the negative electrode, the electrolyte and the positive electrode into a lithium ion battery; and optionally,
--将所述锂离子电池充电，从而使所述正极中的预锂化锂源释放出锂离子，并且使所述负极储存锂，由此将所述负极预锂化。- charging the lithium ion battery such that a pre-lithiation lithium source in the positive electrode releases lithium ions, and the negative electrode stores lithium, thereby pre-lithiation of the negative electrode.
本公开还提供了一种锂离子电池，其包含正极、负极和电解液，其中所述电解液包含锂盐、非水溶剂和选自以下的预锂化锂源：LiVO3、LiV3O8、Li3VO4、Li2C2以及它们的任意组合，优选Li2C2；The present disclosure also provides a lithium ion battery comprising a positive electrode, a negative electrode and an electrolyte, wherein the electrolyte comprises a lithium salt, a non-aqueous solvent, and a pre-lithiation lithium source selected from the group consisting of LiVO 3 , LiV 3 O 8 Li 3 VO 4 , Li 2 C 2 and any combination thereof, preferably Li 2 C 2 ;
优选地，所述电解液还包含硼基阴离子受体。Preferably, the electrolyte further comprises a boron based anion acceptor.
本公开还提供了制备所述锂离子电池的方法，所述方法包括以下步骤：The present disclosure also provides a method of preparing the lithium ion battery, the method comprising the steps of:
--提供电解液，所述电解液包含锂盐、非水溶剂和选自以下的预锂化锂源：LiVO3、LiV3O8、Li3VO4、Li2C2以及它们的任意组合，优选Li2C2；- providing an electrolyte, the electrolyte comprising a lithium salt, a non-aqueous solvent and a pre-selected lithiated lithium source: LiVO 3, LiV 3 O 8 , Li 3 VO 4, Li 2 C 2 , and any combination thereof , preferably Li 2 C 2 ;
--将负极、正极和所述电解液组装成锂离子电池；以及任选地，- assembling the negative electrode, the positive electrode and the electrolyte into a lithium ion battery; and optionally,
--将所述锂离子电池充电，从而使所述电解液中的预锂化锂源释放出锂离子，并且使所述负极储存锂，由此将所述负极预锂化。- charging the lithium ion battery such that a lithium pre-lithiation source in the electrolyte releases lithium ions, and the anode is stored in lithium, thereby pre-lithiation of the anode.
本发明的发明人惊奇地发现，LiVO3、LiV3O8、Li3VO4和/或Li2C2，特别是Li2C2，可以有利地用在锂离子电池的正极和/或电解液中，作为预锂化负极的锂源。通过采用本发明的特定预锂化锂源来将锂离子电池的负极预锂化，可以补偿容量衰减，并且显著改善电池性能(例如，不可逆容量和循环稳定性)。The inventors of the present invention have surprisingly found that LiVO 3 , LiV 3 O 8 , Li 3 VO 4 and/or Li 2 C 2 , especially Li 2 C 2 , can be advantageously used in the positive electrode and/or electrolysis of lithium ion batteries. In the liquid, it serves as a lithium source for the pre-lithiated negative electrode. Pre-lithiation of the negative electrode of a lithium ion battery by employing a particular pre-lithiation lithium source of the present invention can compensate for capacity degradation and significantly improve battery performance (e.g., irreversible capacity and cycle stability).
由于锂粉对空气中的水气具有高活性，在反应期间中会释放出氢气，因此，当在电池中采用锂粉时有发生爆炸的危险。与之相对地，本发明中采用的特定预锂化锂源对空气中的水气相对稳定。Since lithium powder has high activity against moisture in the air, hydrogen gas is released during the reaction, and therefore, there is a risk of explosion when lithium powder is used in the battery. In contrast, the particular pre-lithiation lithium source employed in the present invention is relatively stable to moisture in the air.
特别地，在采用Li2C2作为预锂化锂源时，即使Li2C2与水气发生反应，考虑到Li2C2仅由元素锂和碳构成，反应产物中不会含有不期望的杂质，更不会因为引入的杂质而发生副反应，进而削弱电池性 能。而且，如果Li2C2与空气中的水气发生反应，不会因为产生气体而爆炸，因此，制备电池不要求苛刻的真空环境，这大大改善了生产安全性并且降低了生产成本。In particular, when Li 2 C 2 is used as the lithium source of pre-lithiation, even if Li 2 C 2 reacts with moisture, it is considered that Li 2 C 2 is composed only of elemental lithium and carbon, and the reaction product does not contain undesired The impurities are less likely to cause side reactions due to the introduced impurities, thereby impairing battery performance. Moreover, if Li 2 C 2 reacts with moisture in the air and does not blast due to gas generation, the preparation of the battery does not require a harsh vacuum environment, which greatly improves production safety and reduces production costs.
而且，根据本发明，可以将特定的预锂化锂源提供到正极或电解液中。由于本发明采用的特定预锂化锂源与正极或电解液中包含的其他组分相容，因此，不需要改变正极或电解液的组成。然而，如果将锂粉直接提供到负极的话，需要相应地调整负极中包含的溶剂和粘合剂。Moreover, according to the present invention, a specific pre-lithiation lithium source can be supplied to the positive electrode or the electrolyte. Since the specific pre-lithiation lithium source used in the present invention is compatible with the positive electrode or other components contained in the electrolyte, it is not necessary to change the composition of the positive electrode or the electrolyte. However, if the lithium powder is directly supplied to the negative electrode, it is necessary to adjust the solvent and the binder contained in the negative electrode accordingly.
参考以下附图，本发明的各种其它特征、方面和优点会变得更加显而易见。Various other features, aspects, and advantages of the present invention will become more apparent from the accompanying drawings.
附图说明DRAWINGS
图1示意性地比较了对比例与根据本发明的实施例制备的电池的充/放电性能。Figure 1 is a schematic comparison of the charge/discharge performance of a comparative example with a battery prepared in accordance with an embodiment of the present invention.
图2示意性地比较了对比例与根据本发明的实施例制备的电池的循环性能。Figure 2 is a schematic comparison of the cycling performance of a comparative example with a battery prepared in accordance with an embodiment of the present invention.
具体实施方式detailed description
除非另外定义，本文使用的所有技术和科学术语均为与本发明所属领域技术人员通常理解的含义。若存在不一致的地方，则以本申请提供的定义为准。Unless defined otherwise, all technical and scientific terms used herein have the meanings If there is any inconsistency, the definition provided in this application shall prevail.
除非另外指出，本文所列出的数值范围旨在包括范围的端点，和该范围之内的所有数值和所有子范围。Ranges of values recited herein are intended to include the endpoints of the ranges, and all values and all sub-ranges within the range.
本文的材料、含量、方法、设备、实例和附图均是示例性的，除非特别说明，不应理解为限制性的。The materials, contents, methods, apparatus, examples, and figures are illustrative and are not to be construed as limiting unless otherwise indicated.
在本文中，术语“锂离子电池”与术语“电池”可以互换使用。As used herein, the term "lithium ion battery" is used interchangeably with the term "battery."
本文所用的术语“包含”或“包括”指的是，也可以包含或包括不影响最终效果的其他组分或其他步骤。术语“包含”或“包括”覆盖了“由……构成”和“主要由……构成”的情形。本公开的方法和产品可以包含或包括本文中描述的必要技术特征和/或限定特征，以 及本文中描述的任何其他和/或任选存在的成分、组分、步骤或限定特征。本公开的方法和产品也可以由本文中描述的必要技术特征和/或限定特征构成，或者主要由本文中描述的必要技术特征和/或限定特征构成。The term "comprising" or "including" as used herein means that other components or other steps that do not affect the final effect may also be included or included. The term "comprising" or "including" encompasses the "consisting of" and "consisting primarily of". The methods and products of the present disclosure may comprise or include the necessary technical features and/or defined features described herein to And any other and/or optionally present ingredients, components, steps or defined features described herein. The methods and products of the present disclosure may also be constructed from the essential technical features and/or defined features described herein, or consist essentially of the essential technical features and/or defined features described herein.
术语“正极组合物”或“负极组合物”表示用于形成正极浆料或负极浆料的组合物。所述正极浆料或负极浆料随后可以施加到相应的集流体上，经干燥后，可以形成正极或负极。The term "positive electrode composition" or "negative electrode composition" means a composition for forming a positive electrode slurry or a negative electrode slurry. The positive electrode slurry or the negative electrode slurry may then be applied to a corresponding current collector, and after drying, a positive electrode or a negative electrode may be formed.
除非另外指出，在本文中，特别是在权利要求书中使用“一”、“一种”、“一个”、“所述”或类似的术语时，其后所限定的术语应理解为既可以是单数的，也可以是复数的。Unless otherwise stated, the terms "a", "an", "the", "the" It is singular or plural.
术语“任选存在的”或“任选地”表明两种可替代的备选方案，也就是说，在本文所述的产品和方法中，可以包括也可以不包括术语“任选存在的”或“任选地”所限定的主题。The term "optionally present" or "optionally" indicates two alternative alternatives, that is, in the products and methods described herein, the term "optionally present" may or may not be included. Or "optionally" defined subject matter.
除非另外指出，本文所用的所有材料和试剂均是市售可得的。All materials and reagents used herein are commercially available unless otherwise indicated.
以下将详细描述本发明的实例。Examples of the invention will be described in detail below.
锂离子电池及其制备方法Lithium ion battery and preparation method thereof
在一些实例中，提供锂离子电池，所述锂离子电池包含正极、负极和电解液，其中所述正极包含正极活性材料和选自以下的预锂化锂源：LiVO3、LiV3O8、Li3VO4、Li2C2以及它们的任意组合，优选Li2C2。In some examples, a lithium ion battery is provided, the lithium ion battery comprising a positive electrode, a negative electrode, and an electrolyte, wherein the positive electrode comprises a positive active material and a pre-lithiation lithium source selected from the group consisting of LiVO 3 , LiV 3 O 8 , Li 3 VO 4 , Li 2 C 2 and any combination thereof, preferably Li 2 C 2 .
在一些实例中，提供锂离子电池，其包含正极、负极和电解液，其中所述电解液包含锂盐、非水溶剂和选自以下的预锂化锂源：LiVO3、LiV3O8、Li3VO4、Li2C2以及它们的任意组合，优选Li2C2；In some examples, a lithium ion battery is provided comprising a positive electrode, a negative electrode, and an electrolyte, wherein the electrolyte comprises a lithium salt, a non-aqueous solvent, and a pre-lithiation lithium source selected from the group consisting of LiVO 3 , LiV 3 O 8 , Li 3 VO 4 , Li 2 C 2 and any combination thereof, preferably Li 2 C 2 ;
优选地，所述电解液还包含硼基阴离子受体。Preferably, the electrolyte further comprises a boron based anion acceptor.
在一些实例中，所述锂离子电池是经预锂化或未预锂化的。In some examples, the lithium ion battery is pre-lithiated or not pre-lithiated.
在一些实例中，基于正极组合物的总干重，Li2C2的含量为大于0至约20重量％，优选大于0至小于20重量％，更优选约0.01重量％至约5重量％，再更优选约0.01重量％至约1重量％。In some examples, the Li 2 C 2 content is from greater than 0 to about 20% by weight, preferably from greater than 0 to less than 20% by weight, more preferably from about 0.01% to about 5% by weight, based on the total dry weight of the positive electrode composition, Still more preferably from about 0.01% by weight to about 1% by weight.
在一些实例中，提供制备根据本公开的锂离子电池的方法，所述方法包括以下步骤： In some examples, a method of making a lithium ion battery in accordance with the present disclosure is provided, the method comprising the steps of:
--提供正极，所述正极包含正极活性材料和选自以下的预锂化锂源：LiVO3、LiV3O8、Li3VO4、Li2C2以及它们的任意组合，优选Li2C2；Providing a positive electrode comprising a positive active material and a lithium pre-lithiation source selected from the group consisting of LiVO 3 , LiV 3 O 8 , Li 3 VO 4 , Li 2 C 2 and any combination thereof, preferably Li 2 C 2 ;
--将负极、电解液和所述正极组装成锂离子电池；以及任选地，- assembling the negative electrode, the electrolyte and the positive electrode into a lithium ion battery; and optionally,
--将所述锂离子电池充电，从而使所述正极中的预锂化锂源释放锂离子，并且使所述负极储存锂，由此将所述负极预锂化。- charging the lithium ion battery such that the pre-lithiation lithium source in the positive electrode releases lithium ions, and the negative electrode stores lithium, thereby pre-lithiation of the negative electrode.
在一些实例中，提供制备根据本公开的锂离子电池的方法，，所述方法包括以下步骤：In some examples, a method of making a lithium ion battery in accordance with the present disclosure is provided, the method comprising the steps of:
--提供电解液，所述电解液包含锂盐、非水溶剂和选自以下的预锂化锂源：LiVO3、LiV3O8、Li3VO4、Li2C2以及它们的任意组合，优选Li2C2；Providing an electrolyte comprising a lithium salt, a non-aqueous solvent, and a pre-lithiation lithium source selected from the group consisting of LiVO 3 , LiV 3 O 8 , Li 3 VO 4 , Li 2 C 2 , and any combination thereof , preferably Li 2 C 2 ;
--将负极、正极和所述电解液组装成锂离子电池；以及任选地，- assembling the negative electrode, the positive electrode and the electrolyte into a lithium ion battery; and optionally,
--将所述锂离子电池充电，从而使所述电解液中的预锂化锂源释放出锂离子，并且使所述负极储存锂，由此将所述负极预锂化。- charging the lithium ion battery such that a lithium pre-lithiation source in the electrolyte releases lithium ions, and the anode is stored in lithium, thereby pre-lithiation of the anode.
在一些实例中，基于正极组合物的总干重，所述经预锂化或未预锂化的电池中的Li2C2的含量为大于0至约20重量％，优选大于0至小于20重量％，更优选约0.01重量％至约5重量％，再更优选约0.01重量％至约1重量％。In some examples, the content of Li 2 C 2 in the pre-lithiated or unpre-lithiated cell is greater than 0 to about 20% by weight, preferably greater than 0 to less than 20, based on the total dry weight of the positive electrode composition. % by weight, more preferably from about 0.01% to about 5% by weight, still more preferably from about 0.01% to about 1% by weight.
本发明的发明人惊奇地发现，通过提供本公开的锂离子电池，一方面，可以稳定SEI，补偿容量衰减，并且显著改善电池性能(例如，不可逆容量和循环稳定性)。另一方面，可以避免不期望的锂枝晶。The inventors of the present invention have surprisingly found that by providing the lithium ion battery of the present disclosure, on the one hand, the SEI can be stabilized, the capacity attenuation can be compensated, and the battery performance (e.g., irreversible capacity and cycle stability) can be significantly improved. On the other hand, undesired lithium dendrites can be avoided.
本发明中采用的特定预锂化锂源对空气中的水气相对稳定。特别地，在采用Li2C2作为预锂化锂源时，即使Li2C2与水气发生反应，考虑到Li2C2仅由元素锂和碳构成，反应产物中不会含有不期望的杂质，更不会因为引入的杂质而发生副反应，进而削弱电池性能。而且，如果Li2C2与空气中的水气发生反应，不会因为产生气体而爆炸，因此，制备电池不要求苛刻的真空环境，这大大改善了生产安全性并且降低了生产成本。The particular pre-lithiation lithium source employed in the present invention is relatively stable to moisture in the air. In particular, when Li 2 C 2 is used as the lithium source of pre-lithiation, even if Li 2 C 2 reacts with moisture, it is considered that Li 2 C 2 is composed only of elemental lithium and carbon, and the reaction product does not contain undesired The impurities are less likely to cause side reactions due to the introduced impurities, thereby impairing battery performance. Moreover, if Li 2 C 2 reacts with moisture in the air and does not blast due to gas generation, the preparation of the battery does not require a harsh vacuum environment, which greatly improves production safety and reduces production costs.
此外，根据本发明，可以将特定的预锂化锂源提供到正极或电解液。由于本发明采用的特定预锂化锂源与正极或电解液中包含的其他组分相容，因此，不需要改变正极或电解液的组成。然而，如果将锂 粉直接提供到负极的话，需要相应地调整负极中包含的溶剂和粘合剂。Further, according to the present invention, a specific pre-lithiation lithium source can be supplied to the positive electrode or the electrolyte. Since the specific pre-lithiation lithium source used in the present invention is compatible with the positive electrode or other components contained in the electrolyte, it is not necessary to change the composition of the positive electrode or the electrolyte. However, if lithium is to be When the powder is directly supplied to the negative electrode, it is necessary to adjust the solvent and the binder contained in the negative electrode accordingly.
在一些实例中，在提供包含正极活性材料和预锂化锂源(特别是Li2C2)的正极时，可以采用正极活性材料和预锂化锂源形成正极浆料，然后将正极浆料施加到正极集流体上。具体地，可以将预锂化锂源(特别是Li2C2)与正极组合物的其他组分混合来形成正极浆料，其中，正极组合物的其他组分例如包括正极活性材料、碳材料、粘合剂、溶剂和/或任选存在的添加剂。然后，例如可以通过涂布，来将正极浆料施加到正极集流体上，由此形成包含预锂化锂源的正极。根据本公开，可以很容易地将预锂化锂源引入正极中。预锂化锂源的引入步骤与正极其他组分的添加步骤整合在一起(一体化)，不需要额外的单独添加步骤，也不需要特殊的操作条件，这对于工业生产意味着相当可观的成本降低和劳动节约。In some examples, when a positive electrode including a positive electrode active material and a pre-lithiation lithium source (particularly Li 2 C 2 ) is provided, a positive electrode active material and a pre-lithium lithium source may be used to form a positive electrode slurry, and then the positive electrode slurry is used. Applied to the positive current collector. Specifically, a pre-lithiation lithium source (particularly Li 2 C 2 ) may be mixed with other components of the positive electrode composition to form a positive electrode slurry, wherein other components of the positive electrode composition include, for example, a positive active material, a carbon material , binders, solvents and/or additives optionally present. Then, the positive electrode slurry can be applied to the positive electrode current collector by, for example, coating, thereby forming a positive electrode including a pre-lithiation lithium source. According to the present disclosure, a pre-lithiation lithium source can be easily introduced into the positive electrode. The introduction step of the pre-lithium lithiation source is integrated with the addition step of the other components of the positive electrode (integrated), no additional separate addition steps are required, and no special operating conditions are required, which means considerable cost for industrial production. Reduced and labor saved.
作为替代方案，在提供包含正极活性材料和预锂化锂源(特别是Li2C2)的正极时，也可以将正极活性材料施加到正极集流体上来形成活性材料层，然后可以将预锂化锂源(特别是Li2C2)施加到活性材料层上来形成预锂化锂源层。以这种方式提供预锂化锂源也很容易实施。Alternatively, when a positive electrode including a positive electrode active material and a pre-lithiation lithium source (particularly Li 2 C 2 ) is provided, a positive electrode active material may also be applied to the positive electrode current collector to form an active material layer, and then the pre-lithium may be used. A lithium source (particularly Li 2 C 2 ) is applied to the active material layer to form a pre-lithiated lithium source layer. Providing a pre-lithiation lithium source in this manner is also easy to implement.
根据本公开的锂离子电池可以用在储能系统和电子设备中。A lithium ion battery according to the present disclosure can be used in an energy storage system and an electronic device.
预锂化步骤Prelithiation step
在一些实例中，在前几次(例如第1-5次)充电过程中，从正极或电解液的特定预锂化锂源中释放出锂离子。被释放出来的锂离子插入负极并储存在负极中，由此将负极预锂化。因此，将负极预锂化的前几次充电过程也称为化成(“formation”)或者化成充电(“formation charge”)。在后面的放电/充电循环中，在化成过程中储存在负极中的锂可以参加锂离子迁移，补偿由于形成SEI层而损失的锂，稳定SEI层，并且降低容量衰减。In some instances, lithium ions are released from a particular pre-lithiation lithium source of the positive or electrolyte during the first few (eg, 1-5) charging cycles. The released lithium ions are inserted into the negative electrode and stored in the negative electrode, thereby pre-lithiation of the negative electrode. Therefore, the first several charging processes of pre-lithiation of the negative electrode are also referred to as "formation" or "formation charge". In the subsequent discharge/charge cycle, lithium stored in the negative electrode during the formation process can participate in lithium ion migration, compensate for lithium lost due to formation of the SEI layer, stabilize the SEI layer, and reduce capacity degradation.
根据本公开的一些实例，可以将负极部分地预锂化，从而补偿由于形成SEI损失的锂，并且在正极与负极之间保留期望的锂迁移。According to some examples of the present disclosure, the negative electrode may be partially pre-lithiated to compensate for lithium lost due to formation of SEI and to retain the desired lithium migration between the positive and negative electrodes.
在一些实例中，可以在一定的电压范围内进行化成，所述电压范 围也称为“截止电压”范围。在一些实例中，在将所述锂离子电池充电时，截止电压的上限不低于约3.8V但不高于约5V，优选不低于约4.2V但不高于约5V。在化成过程中，截止电压的上限取决于锂离子电池中包含的正极活性材料。在下文中将详细描述正极活性材料。例如，在正极包含锂镍钴锰氧化物(NCM)或锂镍钴铝氧化物(NCA)作为正极活性材料时，化成过程中的截止电压的上限不低于约4.2V但不高于约5V。在正极包含锂镍钴锰氧化物/Li2MnO3复合物(也称为“锂富集的NCM”)作为正极活性材料时，化成过程中的截止电压的上限不低于约4.35V但不高于约5V。当化成过程中的截止电压的上限落在上述范围内时，一方面，预锂化锂源可以充分释放出锂离子，另一方面，不会严重损害正极。In some instances, the formation may be performed over a range of voltages, also referred to as the "cutoff voltage" range. In some examples, when charging the lithium ion battery, the upper limit of the cutoff voltage is no less than about 3.8V but no greater than about 5V, preferably no less than about 4.2V but no greater than about 5V. In the formation process, the upper limit of the cutoff voltage depends on the positive active material contained in the lithium ion battery. The positive electrode active material will be described in detail below. For example, when the positive electrode contains lithium nickel cobalt manganese oxide (NCM) or lithium nickel cobalt aluminum oxide (NCA) as the positive electrode active material, the upper limit of the cutoff voltage during the formation is not lower than about 4.2 V but not higher than about 5 V. . When the positive electrode contains a lithium nickel cobalt manganese oxide/Li 2 MnO 3 composite (also referred to as "lithium-enriched NCM") as a positive electrode active material, the upper limit of the cutoff voltage during the formation process is not less than about 4.35 V but not Above about 5V. When the upper limit of the cutoff voltage in the formation process falls within the above range, on the one hand, the lithium ion source can sufficiently release lithium ions, and on the other hand, the positive electrode is not seriously damaged.
根据本公开的一些实例，除了在预锂化期间储存在所述负极中的锂元素之外，所述负极的可用于嵌入锂的不可逆容量(单位：mAh/cm2)是所述正极的不可逆容量(单位：mAh/cm2)的约1倍至约1.4倍，优选约1倍至约1.2倍，更优选约1倍至约1.1倍。理想地，负极的不可逆容量与正极的不可逆容量的比值为1。不过，考虑到在制备电池的过程中，不可避免地存在操作误差，因此，所述比值可以大于1。如果负极的不可逆容量与正极的不可逆容量的比值为1至约1.4，既可以避免在负极周围形成锂枝晶，又不会过度消耗负极的不可逆容量。According to some examples of the present disclosure, in addition to the lithium element stored in the negative electrode during pre-lithiation, the irreversible capacity (unit: mAh/cm 2 ) of the negative electrode usable for intercalating lithium is irreversible of the positive electrode The capacity (unit: mAh/cm 2 ) is from about 1 time to about 1.4 times, preferably from about 1 time to about 1.2 times, more preferably from about 1 time to about 1.1 times. Desirably, the ratio of the irreversible capacity of the negative electrode to the irreversible capacity of the positive electrode is one. However, considering that there is inevitably an operational error in the process of preparing the battery, the ratio may be greater than one. If the ratio of the irreversible capacity of the negative electrode to the irreversible capacity of the positive electrode is from 1 to about 1.4, it is possible to avoid formation of lithium dendrites around the negative electrode without excessively consuming the irreversible capacity of the negative electrode.
正极组合物Positive electrode composition
在一些实例中，锂离子电池可以是经预锂化或未预锂化的。In some examples, the lithium ion battery can be pre-lithiated or not pre-lithiated.
根据本公开的一些实例，在预锂化之前，正极组合物可以包含选自以下的预锂化锂源：LiVO3、LiV3O8、Li3VO4、Li2C2以及它们的任意组合，所述预锂化锂源用于将负极预锂化。According to some examples of the present disclosure, prior to pre-lithiation, the positive electrode composition may comprise a pre-lithiation lithium source selected from the group consisting of LiVO 3 , LiV 3 O 8 , Li 3 VO 4 , Li 2 C 2 , and any combination thereof. The pre-lithiation lithium source is used to pre-lithiation the negative electrode.
在一些实例中，基于正极组合物的总干重，Li2C2的含量为大于0至约20重量％，优选大于0至小于20重量％，更优选约0.01重量％至约5重量％，再更优选约0.01重量％至约1重量％。如果预锂化锂源的含量落在上述范围内的话，一方面，可以充分补偿由于形成SEI损失的锂，另一方面，可以避免产生不期望的锂枝晶。 In some examples, the Li 2 C 2 content is from greater than 0 to about 20% by weight, preferably from greater than 0 to less than 20% by weight, more preferably from about 0.01% to about 5% by weight, based on the total dry weight of the positive electrode composition, Still more preferably from about 0.01% by weight to about 1% by weight. If the content of the pre-lithiation lithium source falls within the above range, on the one hand, lithium which is lost due to the formation of SEI can be sufficiently compensated, and on the other hand, undesired lithium dendrites can be avoided.
在预锂化之后，正极组合物可以包含痕量的预锂化锂源。在一些实例中，在预锂化之后，基于正极组合物的总干重，Li2C2的含量为约0.01重量％至约1重量％。After pre-lithiation, the positive electrode composition may contain traces of a source of pre-lithiation lithium. In some examples, after the pre-lithiated positive electrode based on the total dry weight of the composition, the content of Li 2 C 2 is from about 0.01% to about 1 wt%.
可以采用锂和碳为原料，通过已知方法来制备Li2C2。例如，Jiangtao He等在“Preparation and phase stability of nanocrystalline Li2C2alloy”，Materials Letters 94(2013)，第176-178页，公开了制备Li2C2的方法。该文献全文以援引的方式并入本文。Li 2 C 2 can be produced by a known method using lithium and carbon as raw materials. For example, Jiangtao He et al., "Preparation and phase stability of nanocrystalline Li 2 C 2 alloy", Materials Letters 94 (2013), pages 176-178, discloses a process for preparing Li 2 C 2 . This document is incorporated herein by reference in its entirety.
对预锂化锂源的粒径没有特殊限制，纳米级(小于1微米)或微米级(大于1微米但小于1毫米)的粒径均可用于本公开；优选纳米级。The particle size of the pre-lithiation lithium source is not particularly limited, and nanometer-sized (less than 1 micrometer) or micrometer-sized (greater than 1 micrometer but less than 1 millimeter) particle size can be used in the present disclosure; nanoscale is preferred.
根据本公开的一些实例，除了预锂化锂源之外，正极还可以包含锂基活性材料。在一些实例中，正极活性材料是在充/放电循环中，可以可逆地脱嵌和嵌入锂离子的材料。在放电循环中，得自正极活性材料的锂离子可以从负极回到正极，再次形成正极活性材料。According to some examples of the present disclosure, in addition to the pre-lithiation lithium source, the positive electrode may further comprise a lithium-based active material. In some examples, the positive active material is a material that can reversibly deintercalate and intercalate lithium ions in a charge/discharge cycle. In the discharge cycle, lithium ions obtained from the positive electrode active material can be returned from the negative electrode to the positive electrode to form the positive electrode active material again.
相对于用作基本锂源的正极活性材料，预锂化锂源可以称作“额外的锂源”或者“附加的锂源”。The prelithium lithium source may be referred to as an "extra lithium source" or an "additional lithium source" relative to the positive active material used as the base lithium source.
对于正极活性材料没有特别限制，常用于锂离子电池中的正极活性材料均可用于本公开。在一些实例中，正极活性材料可以不同于预锂化锂源。在一些实例中，正极活性材料可以选自锂-金属氧化物、锂-金属磷酸盐、锂-金属硅酸盐、硫化物和它们的任意组合，优选锂-过渡金属复合氧化物、锂-过渡金属磷酸盐、锂-金属硅酸盐、金属硫化物和它们的任意组合。在一些实例中，锂-过渡金属磷酸盐可以选自磷酸锂铁、磷酸锂锰、磷酸锂锰铁和它们的任意组合。在一些实例中，锂-过渡金属复合氧化物可以选自锂镍氧化物、锂钴氧化物、锂锰氧化物、锂镍钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物(NCM)，锂镍钴铝氧化物(NCA)、锂镍钴锰氧化物/Li2MnO3复合物(也称为“锂富集的NCM”)、或它们的任意组合。在一些实例中，金属硫化物可以为硫化铁。The positive electrode active material is not particularly limited, and a positive electrode active material which is commonly used in a lithium ion battery can be used in the present disclosure. In some examples, the positive active material may be different from the pre-lithiation lithium source. In some examples, the positive active material may be selected from the group consisting of lithium-metal oxides, lithium-metal phosphates, lithium-metal silicates, sulfides, and any combination thereof, preferably lithium-transition metal composite oxides, lithium-transitions Metal phosphates, lithium-metal silicates, metal sulfides, and any combination thereof. In some examples, the lithium-transition metal phosphate can be selected from the group consisting of lithium iron phosphate, lithium manganese phosphate, lithium manganese phosphate, and any combination thereof. In some examples, the lithium-transition metal composite oxide may be selected from the group consisting of lithium nickel oxide, lithium cobalt oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (NCM). Lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide / Li 2 MnO 3 composite (also referred to as "lithium enriched NCM"), or any combination thereof. In some examples, the metal sulfide can be iron sulfide.
根据本公开的一些实例，除了预锂化锂源和正极活性材料之外，正极组合物还可以包含碳材料。“碳材料”指的是含碳元素的材料。在本公开中，碳材料可以用于改善电池正极组合物的导电性和/或分 散性。对碳材料没有特别限制，常用于锂离子电池的碳材料均可用于本公开。在一些实例中，碳材料可以选自炭黑、超导电炭黑(例如，购自Timcal公司的Super P)、乙炔黑、科琴黑、石墨、石墨烯、碳纳米管、碳纤维、气相生长的碳纤维和它们的组合。在一些实例中，正极组合物中可以包含两种或更多种碳材料的混合物。在一些实例中，正极组合物可以同时包含两种或更多种具有不同粒径的碳材料，例如，粒径不小于1微米的碳材料，和粒径小于1微米的相同或不同种类的碳材料。According to some examples of the present disclosure, the positive electrode composition may further contain a carbon material in addition to the pre-lithiation lithium source and the positive electrode active material. "Carbon material" refers to a material containing carbon. In the present disclosure, a carbon material can be used to improve the conductivity and/or the fraction of the battery positive electrode composition. Scattered. The carbon material is not particularly limited, and a carbon material commonly used for a lithium ion battery can be used in the present disclosure. In some examples, the carbon material may be selected from the group consisting of carbon black, superconducting carbon black (eg, Super P from Timcal Corporation), acetylene black, ketjen black, graphite, graphene, carbon nanotubes, carbon fiber, vapor grown Carbon fiber and combinations thereof. In some examples, a mixture of two or more carbon materials may be included in the positive electrode composition. In some examples, the positive electrode composition may simultaneously contain two or more carbon materials having different particle diameters, for example, a carbon material having a particle diameter of not less than 1 μm, and the same or different kinds of carbon having a particle diameter of less than 1 μm. material.
根据本公开的一些实例，除了预锂化锂源和正极活性材料之外，正极组合物还可以包含粘合剂。粘合剂可以将正极组合物的各组分结合在一起，并且将正极组合物粘附在正极集流体上。在重复的充/放电循环引起体积变化时，粘合剂有助于正极保持良好的稳定性和完整性，由此改善最终电池的电化学性能(包括循环性能和倍率性能)。对于粘合剂没有特别限制，常用于锂离子电池的粘合剂均可用于本公开。在一些实例中，粘合剂可以为聚偏二氟乙烯(PVDF)、聚丙烯酸(PAA)、羧甲基纤维素钠(CMC)，优选PVDF。According to some examples of the present disclosure, the positive electrode composition may further include a binder in addition to the pre-lithiation lithium source and the positive electrode active material. The binder may bond the components of the cathode composition together and adhere the cathode composition to the cathode current collector. The binder helps the positive electrode maintain good stability and integrity when repeated charge/discharge cycles cause volume changes, thereby improving the electrochemical performance (including cycling performance and rate performance) of the final cell. There is no particular limitation on the binder, and an adhesive commonly used for a lithium ion battery can be used in the present disclosure. In some examples, the binder can be polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), sodium carboxymethylcellulose (CMC), preferably PVDF.
根据本公开的一些实例，正极组合物还可以包含溶剂。溶剂可用于溶解正极组合物中的其他组分，从而提供正极浆料。然后，可以将得到的正极浆料施加到正极集流体上，并且干燥，从而获得正极。对于正极组合物中包含的溶剂没有特别限制，常用于锂离子电池中的溶剂均可用于本公开。在一些实例中，正极组合物中的溶剂可以为N-甲基-2-吡咯烷酮(NMP)。According to some examples of the present disclosure, the positive electrode composition may further comprise a solvent. The solvent can be used to dissolve other components in the positive electrode composition to provide a positive electrode slurry. Then, the obtained positive electrode slurry can be applied to the positive electrode current collector and dried to obtain a positive electrode. The solvent contained in the positive electrode composition is not particularly limited, and a solvent commonly used in a lithium ion battery can be used in the present disclosure. In some examples, the solvent in the positive electrode composition may be N-methyl-2-pyrrolidone (NMP).
在一些实例中，正极组合物可以包含预锂化锂源、正极活性材料、碳材料、粘合剂和溶剂，其中所述预锂化锂选自LiVO3、LiV3O8、Li3VO4、Li2C2以及它们的任意组合。此外，正极组合物还可以任选地包含常用于锂离子电池中的其他添加剂，只要这些添加剂不会不利地削弱电池的期望性能即可。In some examples, the positive electrode composition may include a pre-lithiation lithium source, a positive electrode active material, a carbon material, a binder, and a solvent, wherein the pre-lithium lithiate is selected from the group consisting of LiVO 3 , LiV 3 O 8 , and Li 3 VO 4 . Li 2 C 2 and any combination thereof. Further, the positive electrode composition may also optionally contain other additives commonly used in lithium ion batteries as long as these additives do not adversely impair the desired properties of the battery.
对于正极组合物中各组分的类型、形状、尺寸和/或含量没有特别限制。There is no particular limitation on the type, shape, size and/or content of each component in the positive electrode composition.
对于正极集流体没有特别限制。在一些实例中，可以将铝箔用作 正极集流体。There is no particular limitation on the cathode current collector. In some examples, aluminum foil can be used as Positive current collector.
负极组合物Negative electrode composition
根据本公开的一些实例，负极组合物可以包含负极活性材料。对于负极活性材料没有特别限制，常用于锂离子电池中的负极活性材料均可用于本公开。在一些实例中，负极活性材料可以选自硅基活性材料、碳基活性材料和它们的任意组合。According to some examples of the present disclosure, the anode composition may include a cathode active material. The negative electrode active material is not particularly limited, and a negative electrode active material which is commonly used in a lithium ion battery can be used in the present disclosure. In some examples, the negative active material may be selected from the group consisting of silicon-based active materials, carbon-based active materials, and any combination thereof.
“硅基活性材料”指的是含硅元素的活性材料。适合的硅基活性材料可以包括，但不限于硅、硅合金、硅氧化物、硅/碳复合物和硅氧化物/碳复合物和它们的任意组合。在一些实例中，硅合金可以包含硅和选自钛、锡、铝、锑、铋、砷、锗和铅中的一种或多种金属。在一些实例中，硅氧化物可以是硅的两种或更多种氧化物的混合物，例如，硅氧化物可以由SiOx表示，x的平均值为约0.5至约2。"Si-based active material" refers to an active material containing silicon. Suitable silicon-based active materials can include, but are not limited to, silicon, silicon alloys, silicon oxides, silicon/carbon composites, and silicon oxide/carbon composites, and any combination thereof. In some examples, the silicon alloy may comprise silicon and one or more metals selected from the group consisting of titanium, tin, aluminum, lanthanum, cerium, arsenic, antimony, and lead. In some examples, the silicon oxide can be a mixture of two or more oxides of silicon, for example, the silicon oxide can be represented by SiO x with an average value of x of from about 0.5 to about 2.
负极中的碳基活性材料可以与正极中包含的碳材料相同或不同。适合的碳基活性材料的实例可以包括，但不限于石墨、石墨烯、硬碳、碳黑和碳纳米管。The carbon-based active material in the negative electrode may be the same as or different from the carbon material contained in the positive electrode. Examples of suitable carbon-based active materials may include, but are not limited to, graphite, graphene, hard carbon, carbon black, and carbon nanotubes.
与正极组合物类似地，负极组合物还可以包含碳材料、粘合剂和/或溶剂。负极中的碳材料、粘合剂和/或溶剂可以分别与正极包含的碳材料、粘合剂和/或溶剂相同或不同。此外，负极组合物还可以任选地包含常用于锂离子电池中的其他添加剂，只要这些添加剂不会不利地削弱电池的期望性能即可。Similar to the positive electrode composition, the negative electrode composition may further contain a carbon material, a binder, and/or a solvent. The carbon material, binder, and/or solvent in the negative electrode may be the same as or different from the carbon material, binder, and/or solvent contained in the positive electrode, respectively. Further, the negative electrode composition may also optionally contain other additives commonly used in lithium ion batteries as long as these additives do not adversely impair the desired properties of the battery.
对于负极组合物中各组分的类型、形状、尺寸和/或含量没有特别限制。There is no particular limitation on the type, shape, size and/or content of each component in the negative electrode composition.
对于负极集流体没有特别限制。在一些实例中，可以将镍箔、镍网、铜箔或铜网用作负极集流体。There is no particular limitation on the anode current collector. In some examples, a nickel foil, a nickel mesh, a copper foil, or a copper mesh can be used as the negative current collector.
电解液Electrolyte
根据本公开，锂离子电池可以包含电解液。在一些实例中，电解液可以包含锂盐和非水溶剂。这里，非水溶剂可以不同于水或者不含水，并且可以是无机溶剂或有机溶剂。对锂盐和非水溶剂没有特殊限制，已知可用于锂离子电池的那些锂盐和非水溶剂均可用于本公开。 在一些实例中，电解液中的锂盐可以不同于正极活性材料和预锂化锂源。在一些实例中，锂盐可以包括，但不限于六氟磷酸锂(LiPF6)、四氟硼酸锂(LiBF4)、砷酸锂(LiAsO4)、LiSbO4、高氯酸锂(LiClO4)、LiAlO4、LiGaO4、二草酸硼酸锂(lithium bis(oxalate)borate，LiBOB)以及它们的任意组合，优选LiPF6。According to the present disclosure, a lithium ion battery may contain an electrolyte. In some examples, the electrolyte may comprise a lithium salt and a non-aqueous solvent. Here, the nonaqueous solvent may be different from or not containing water, and may be an inorganic solvent or an organic solvent. The lithium salt and the nonaqueous solvent are not particularly limited, and those lithium salts and nonaqueous solvents known to be usable for lithium ion batteries can be used in the present disclosure. In some examples, the lithium salt in the electrolyte can be different from the positive active material and the pre-lithiation lithium source. In some examples, the lithium salt may include, but is not limited to, lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium arsenate (LiAsO 4 ), LiSbO 4 , lithium perchlorate (LiClO 4 ), LiAlO 4 . LiGaO 4 , lithium bis(oxalate)borate, LiBOB, and any combination thereof, preferably LiPF 6 .
根据本公开的一些实例，非水溶剂可以是非氟化碳酸酯(以下简称“碳酸酯”)和/或氟化碳酸酯。在一些实例中，碳酸酯包括，但不限于环状碳酸酯，例如碳酸亚乙酯(EC)、碳酸亚丙酯(PC)和碳酸亚丁酯(BC)；线性碳酸酯，例如碳酸二甲酯(DMC)、碳酸二乙酯(DEC)、碳酸二丙酯(DPC)、碳酸甲乙酯(EMC)、碳酸甲丙酯(MPC)和碳酸乙丙酯(EPC)；以及上述碳酸酯的任意组合。在一些实例中，氟化碳酸酯可以是上述碳酸酯的氟化衍生物，例如氟代亚乙基碳酸酯(FEC)、二氟代亚乙基碳酸酯以及二氟代碳酸二甲酯(DFDMC)。According to some examples of the present disclosure, the non-aqueous solvent may be a non-fluorinated carbonate (hereinafter referred to as "carbonate") and/or a fluorinated carbonate. In some examples, carbonates include, but are not limited to, cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC); linear carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), ethyl methyl carbonate (EMC), methylpropyl carbonate (MPC) and ethylene propyl carbonate (EPC); and any of the above carbonates combination. In some examples, the fluorinated carbonate may be a fluorinated derivative of the above carbonates, such as fluoroethylene carbonate (FEC), difluoroethylene carbonate, and dimethyl difluorocarbonate (DFDMC). ).
电解液中的硼基阴离子受体Boron-based anion receptor in electrolyte
在一些实例中，除了锂盐和非水溶剂之外，电解液还可以包含硼基阴离子受体(即，可以接受阴离子的含硼的物质)。对硼基阴离子受体没有特殊限制，硼烷、硼酸酯和硼酸盐盐均可使用，只要它们在硼原子上具有路易斯酸中心，并且可以与具有路易斯碱中心的预锂化锂源(例如Li2C2)形成络合物。通过使用这类硼烷、硼酸酯或硼酸盐，可以增加预锂化锂源(例如Li2C2)在电解液中的溶解性，并且可以改善预锂化锂源脱嵌锂的动力学，促进预锂化锂源释放出锂离子。当电解质包含对热不稳定的锂盐(例如LiPF6)时，硼烷、硼酸酯或硼酸盐还可以稳定阴离子(例如PF6 5-)，并且减少锂盐的分解。其中，锂盐的分解在充/放电循环中会导致容量衰减并且增加电阻。In some examples, in addition to the lithium salt and the non-aqueous solvent, the electrolyte may also contain a boron-based anion acceptor (ie, a boron-containing material that can accept anions). The boron-based anion acceptor is not particularly limited, and borane, borate ester and borate salt can be used as long as they have a Lewis acid center on the boron atom and can be combined with a pre-lithiation lithium source having a Lewis base center ( For example, Li 2 C 2 ) forms a complex. By using such borane, borate or borate, the solubility of the pre-lithiation lithium source (for example, Li 2 C 2 ) in the electrolyte can be increased, and the power of the prelithiation lithium source to deintercalate lithium can be improved. Learn to promote the release of lithium ions from the pre-lithiation lithium source. When the electrolyte contains lithium salts is unstable to heat (e.g., LiPF 6), a borane, a borate or borate anion can stabilize (e.g., PF 6 5-), and reduce the decomposition of the lithium salt. Among them, the decomposition of the lithium salt causes capacity decay and increases resistance in the charge/discharge cycle.
例如，根据本公开，可以采用式(氟代烷基-O)3-B表示的硼烷、式(氟代芳基-O)3-B表示的硼烷、以及式(氟代芳基)3-B表示的硼烷，参见H.S.Lee等，J.Electochem.Soc.，145(1998)，第2813-2818页，该文献全文通过援引的方式并入本文。示例性的硼酸酯可以包括，但不限于，硼酸三(2H-六氟异丙基)酯(THFPB，[(CF3)2CHO]3B)和硼酸 三(2，4-二氟乙基)酯(F2C6H3O)3B。示例性的硼烷可以包括，但不限于，三(五氟苯基)硼烷(TPFPB，(C6F5)3B)。For example, according to the present disclosure, a borane represented by the formula (fluoroalkyl-O) 3 -B, a borane represented by the formula (fluoroaryl-O) 3 -B, and a formula (fluoroaryl) may be employed. Borane represented by 3- B, see HS Lee et al, J. Electochem. Soc., 145 (1998), pp. 2813-2818, which is incorporated herein by reference in its entirety. Exemplary borate ester may include, but are not limited to, borate, tri (2H- hexafluoroisopropyl yl) ester (THFPB, [(CF 3) 2 CHO] 3 B) , and tri (2,4-difluoro-B ()) ester (F 2 C 6 H 3 O) 3 B. Exemplary boranes can include, but are not limited to, tris(pentafluorophenyl)borane (TPFPB, (C 6 F 5 ) 3 B).
也可以采用美国专利申请公开号US2012/0183866 A1中公开的氟代芳基硼的草酸酯(fluorinated arylboron oxalates)，该专利申请的全文也通过援引的方式并入本文。示例性的氟代芳基硼的草酸酯可以由下式表示：Fluorinated arylboron oxalates as disclosed in U.S. Patent Application Publication No. US 2012/0183866 A1, which is incorporated herein by reference in its entirety herein. An exemplary oxalate boron oxalate can be represented by the formula:
Figure PCTCN2017072568-appb-000001
Figure PCTCN2017072568-appb-000001
其中R是含氟的部分。氟代芳基硼的草酸酯的非限制性例子可以包括，但不限于五氟苯基硼的草酸酯(pentafluorophenylboronoxalate，PFPBO)。Wherein R is a fluorine-containing moiety. Non-limiting examples of oxalate boron oxalates may include, but are not limited to, pentafluorophenylboronoxalate (PFPBO).
也可以采用下式表示的二草酸硼酸锂(Lithium bis(oxalato)borate，LiBOB)作为电解液中的硼基阴离子受体：Lithium bis(oxalato)borate (LiBOB) represented by the following formula may also be used as a boron-based anion acceptor in the electrolyte:
Figure PCTCN2017072568-appb-000002
Figure PCTCN2017072568-appb-000002
另外，美国专利申请号US 10/625686中描述的草酸二氟硼酸锂(lithium oxaltodifluoroborate，化学式LiBF2C2O4，缩写为LiODFB)也可用作电解液中的硼基阴离子受体。In addition, lithium oxaltodifluoroborate (chemical formula LiBF 2 C 2 O 4 , abbreviated as LiODFB) described in US Pat. No. 10/625,686 can also be used as a boron-based anion acceptor in an electrolyte.
氟代芳基硼的草酸酯(例如PFPBO)、LiBOB和LIODFB均有助于在负极表面形成更稳定的SEI层，从而可以降低锂的消耗，改善电池性能。The oxalate boron oxalates (such as PFPBO), LiBOB, and LIODFB all contribute to the formation of a more stable SEI layer on the surface of the negative electrode, thereby reducing lithium consumption and improving battery performance.
实施例Example
材料material
NCM-111：锂镍钴锰氧化物，正极活性材料，D50：12μm，购自BASF。NCM-111: lithium nickel cobalt manganese oxide, positive active material, D50: 12 μm, available from BASF.
Super P：超导电炭黑，碳材料，40nm，购自Timcal。Super P: superconducting carbon black, carbon material, 40 nm, available from Timcal.
KS6L：片状石墨，碳材料，约6μm，购自Timcal。KS6L: flake graphite, carbon material, about 6 μm, purchased from Timcal.
PVDF：聚偏二氟乙烯，粘合剂，购自Sovey。PVDF: polyvinylidene fluoride, binder, available from Sovey.
NMP：N-甲基-2-吡咯烷酮，溶剂，购自国药集团化学试剂有限公司。NMP: N-methyl-2-pyrrolidone, solvent, purchased from Sinopharm Chemical Reagent Co., Ltd.
Celgard 2325：聚丙烯/聚乙烯/聚丙烯层合膜(PP/PE/PP膜)，隔膜，购自Celgard。 Celgard 2325: polypropylene/polyethylene/polypropylene laminate film (PP/PE/PP film), separator, available from Celgard.
实施例1Example 1
[Li2C2的制备][Preparation of Li 2 C 2 ]
根据Jiangtao He等人在“Preparation and phase stability of nanocrystalline Li2C2alloy”，Materials Letters 94(2013)，第176-178页公开的方法来制备Li2C2的方法。The method for preparing Li 2 C 2 according to the method disclosed by Jiangtao He et al., "Preparation and phase stability of nanocrystalline Li 2 C 2 alloy", Materials Letters 94 (2013), pp. 176-178.
具体地，在碳化钨模具中，将29.96mg锂带(99.99％)与48mg碳粉(99.9％)以1.07∶1的摩尔比混合并压实。然后，将装有所述混合物的磨具置于放电等离子体烧结炉(spark plasma sintering system，简称SPS)中烧结1小时。在所述SPS炉中，将真空度设为1.6×10-2Pa，温度设为600℃，得到块状物。将所述块状物压碎，并在球磨机中以500rpm的转速研磨12小时，得到磨碎的颗粒。将得到的颗粒置于金属陶瓷模具中，然后立即将装有所述粉末的金属陶瓷模具置于放电等离子体烧结炉中再次烧结。其中，在所述SPS炉中，将外压设为300MPa，加热速率设为50℃/分钟，当温度达到350℃时，恒温保持2分钟，由此得到72mg细粉末。对得到的细粉进行XRD衍射，发现所有的峰值均与已知的Li2C2[JCPDS No.70-3193]相符。Specifically, in a tungsten carbide mold, 29.96 mg of lithium ribbon (99.99%) and 48 mg of carbon powder (99.9%) were mixed and compacted at a molar ratio of 1.07:1. Then, the abrasive containing the mixture was placed in a spark plasma sintering system (SPS) for 1 hour. In the SPS furnace, the degree of vacuum was set to 1.6 × 10 -2 Pa, and the temperature was set to 600 ° C to obtain a cake. The cake was crushed and ground in a ball mill at 500 rpm for 12 hours to obtain ground granules. The obtained granules were placed in a cermet mold, and then the cermet mold containing the powder was immediately placed in a discharge plasma sintering furnace to be sintered again. Here, in the SPS furnace, the external pressure was set to 300 MPa, the heating rate was set to 50 ° C / minute, and when the temperature reached 350 ° C, the temperature was maintained for 2 minutes, thereby obtaining 72 mg of fine powder. The obtained fine powder was subjected to XRD diffraction, and it was found that all the peaks were in agreement with the known Li 2 C 2 [JCPDS No. 70-3193].
[正极的制备][Preparation of positive electrode]
在填充有氩气的手套箱(MB-10compact，购自MBraun)中，将938.6mg NCM-111、26.4mg的前面制得的Li2C2、10mg Super P、5mg KS6L、20mg PVDF添加到450mL NMP。在搅拌3小时之后，将得到的均匀分散的浆料涂布到铝箔上，然后在真空中于80℃干燥6小时。将经涂布的铝箔从手套箱中取出，并用EQ-T-06电池极片冲片机(购自深圳市威智达光电科技有限公司)冲压成多个12mm的正极极片(缩写为NCM-Li2C2)。In a glove box filled with argon (MB-10compact, available from MBraun), 938.6 mg NCM-111, 26.4 mg of the previously prepared Li 2 C 2 , 10 mg Super P, 5 mg KS6L, 20 mg PVDF were added to 450 mL. NMP. After stirring for 3 hours, the obtained uniformly dispersed slurry was applied onto an aluminum foil, followed by drying at 80 ° C for 6 hours in a vacuum. The coated aluminum foil was taken out from the glove box and punched into a plurality of 12 mm positive electrode sheets (abbreviated as NCM) using an EQ-T-06 battery pole piece punching machine (purchased from Shenzhen Weizhida Optoelectronics Technology Co., Ltd.). -Li 2 C 2 ).
[电池的制备][Preparation of battery]
在填充有氩气的手套箱(MB-10compact，购自MBraun)中，采用上面得到的正极极片来组装纽扣电池(CR2016)。将纯锂金属箔用作对电极。将FEC/EMC(体积比为3∶7，氟代亚乙基碳酸酯(FEC)与碳酸甲乙酯(EMC)的混合物)中的1M LiPF6用作电解液。将Celgard 2325(PP/PE/PP膜)用作隔膜。In a glove box filled with argon (MB-10 compact, available from MBraun), a coin battery (CR2016) was assembled using the positive electrode tab obtained above. A pure lithium metal foil was used as the counter electrode. 1 M LiPF 6 in FEC/EMC (3:7 by volume, a mixture of fluoroethylene carbonate (FEC) and ethyl methyl carbonate (EMC)) was used as the electrolyte. Celgard 2325 (PP/PE/PP film) was used as the separator.
对比例1Comparative example 1
以与实施例1中相同的方式来制备正极极片(缩写为NCM)，除了不采用Li2C2，并且采用965mg NCM-111来代替938.6mg NCM-111。A positive electrode tab (abbreviated as NCM) was prepared in the same manner as in Example 1, except that Li 2 C 2 was not used, and 965 mg of NCM-111 was used instead of 938.6 mg of NCM-111.
[锂离子电池的电化学性能测试][Electrochemical performance test of lithium ion battery]
在25℃，在Arbin电池测试系统(购自Arbin Corporation)中，测试电池的充/放电容量和循环性能。The charge/discharge capacity and cycle performance of the battery were tested at 25 ° C in an Arbin battery test system (available from Arbin Corporation).
图1比较了对比例1与实施例1制备的电池在第1次充/放电循环时的充/放电性能。在第1次充/放电循环中，在3-4.6V(vs Li/Li+)的电压范围内对每个电池进行充/放电。在每个电池的正极中，NCM的质量负载为约10mg/cm2。基于NCM的重量来计算比容量(specific capacity)。从图1可以看出，与对比例1中NCM正极相比，实施例1中的NCM-Li2C2正极改善了第1次充电时的充电容量。Fig. 1 compares the charge/discharge performance of the battery prepared in Comparative Example 1 and Example 1 at the first charge/discharge cycle. In the first charge/discharge cycle, each battery was charged/discharged in a voltage range of 3-4.6 V (vs Li/Li + ). In the positive electrode of each cell, the mass loading of NCM was about 10 mg/cm 2 . The specific capacity is calculated based on the weight of the NCM. As can be seen from Fig. 1, the NCM-Li 2 C 2 positive electrode of Example 1 improved the charging capacity at the time of the first charge as compared with the NCM positive electrode of Comparative Example 1.
图2比较了对比例1与实施例1制备的电池的循环性能。在第1次充/放电循环中，在3-4.6V(vs Li/Li+)的电压范围内对每个电池进行充/放电；然后，在第2-80次充/放电循环中，3-4.3V(vs Li/Li+)的电压范围内对每个电池进行充/放电。在每个电池的正极中，NCM的质量负载为约10mg/cm2。基于NCM的重量来计算比容量。从图2可以看出，与对比例1中NCM正极相比，实施例1中的NCM-Li2C2正极显示出改善的容量和稳定性。Figure 2 compares the cycle performance of Comparative Example 1 with the battery prepared in Example 1. In the first charge/discharge cycle, each battery is charged/discharged in a voltage range of 3-4.6 V (vs Li/Li + ); then, in the second to 80 charge/discharge cycles, 3 Each battery is charged/discharged within a voltage range of -4.3 V (vs Li/Li + ). In the positive electrode of each cell, the mass loading of NCM was about 10 mg/cm 2 . The specific capacity is calculated based on the weight of the NCM. As can be seen from FIG. 2, the NCM-Li 2 C 2 positive electrode in Example 1 showed improved capacity and stability as compared with the NCM positive electrode in Comparative Example 1.
本文中描述了本公开的优选实施方案，包括发明人已知的用于实施要求保护的主题的最佳方式。对于本领域技术人员来说，当阅读前述说明时，那些优选实施方案的变体可变得显而易见。发明人预期本领域技术人员能恰当地使用此类变体，并且发明人意欲使本公开能以有别于本文中具体描述的方式实践。因此，本公开包括可适用的方法所允许的本文所附权利要求中所述主题的所有修改和等效形式。此外，除非本文另外指明或者上下文明显矛盾，否则本公开涵盖其所有可能的变体中上述因素的任何组合。 Preferred embodiments of the present disclosure are described herein, including the best mode known to the inventors for carrying out the claimed subject matter. Variations of those preferred embodiments may become apparent to those skilled in the art upon reading the foregoing description. The inventors intend for the present invention to be able to use such variations as appropriate, and the inventors intend to make the present disclosure practice in a manner different from those specifically described herein. Accordingly, this disclosure includes all modifications and equivalents of the subject matter described in the appended claims. In addition, the present disclosure encompasses any combination of the above factors in all possible variations thereof, unless otherwise indicated herein or clearly contradicted by context.

Claims (11)

  1. 锂离子电池，其包含正极、负极和电解液，其中所述正极包含正极活性材料和选自以下的预锂化锂源：LiVO3、LiV3O8、Li3VO4、Li2C2以及它们的任意组合，优选Li2C2。a lithium ion battery comprising a positive electrode, a negative electrode, and an electrolyte, wherein the positive electrode comprises a positive active material and a pre-lithiation lithium source selected from the group consisting of LiVO 3 , LiV 3 O 8 , Li 3 VO 4 , Li 2 C 2 , and Any combination thereof is preferably Li 2 C 2 .
  2. 根据权利要求1所述的锂离子电池，其中所述锂离子电池是经预锂化或未预锂化的；以及The lithium ion battery of claim 1 wherein said lithium ion battery is pre-lithiated or not pre-lithiated;
    基于正极组合物的总干重，Li2C2的含量为大于0至约20重量％，优选大于0至小于20重量％，更优选约0.01重量％至约5重量％，再更优选约0.01重量％至约1重量％。The content of Li 2 C 2 is from more than 0 to about 20% by weight, preferably from more than 0 to less than 20% by weight, more preferably from about 0.01% by weight to about 5% by weight, still more preferably about 0.01, based on the total dry weight of the positive electrode composition. From % by weight to about 1% by weight.
  3. 根据权利要求1或2所述的锂离子电池，其中所述正极活性材料选自锂-金属氧化物、锂-金属磷酸盐、锂-金属硅酸盐、硫化物和它们的任意组合。The lithium ion battery according to claim 1 or 2, wherein the positive active material is selected from the group consisting of lithium-metal oxides, lithium-metal phosphates, lithium-metal silicates, sulfides, and any combination thereof.
  4. 根据前述权利要求中任一项所述的锂离子电池，其中，所述负极包含负极活性材料，并且所述负极活性材料选自硅基活性材料、碳基活性材料和它们的任意组合。The lithium ion battery according to any one of the preceding claims, wherein the negative electrode comprises a negative active material, and the negative active material is selected from the group consisting of a silicon-based active material, a carbon-based active material, and any combination thereof.
  5. 根据前述权利要求中任一项所述的锂离子电池，其中，所述电解液包含锂盐和非水溶剂；A lithium ion battery according to any one of the preceding claims, wherein the electrolyte comprises a lithium salt and a non-aqueous solvent;
    优选地，所述电解液还包含硼基阴离子受体。Preferably, the electrolyte further comprises a boron based anion acceptor.
  6. 制备根据权利要求1-5中任一项所述的锂离子电池的方法，所述方法包括以下步骤：A method of preparing a lithium ion battery according to any one of claims 1 to 5, the method comprising the steps of:
    --提供正极，所述正极包含正极活性材料和选自以下的预锂化锂源：LiVO3、LiV3O8、Li3VO4、Li2C2以及它们的任意组合，优选Li2C2；Providing a positive electrode comprising a positive active material and a lithium pre-lithiation source selected from the group consisting of LiVO 3 , LiV 3 O 8 , Li 3 VO 4 , Li 2 C 2 and any combination thereof, preferably Li 2 C 2 ;
    --将负极、电解液和所述正极组装成锂离子电池；以及任选地，- assembling the negative electrode, the electrolyte and the positive electrode into a lithium ion battery; and optionally,
    --将所述锂离子电池充电，从而使所述正极中的预锂化锂源释 放出锂离子，并且使所述负极储存锂，由此将所述负极预锂化。- charging the lithium ion battery to release the prelithiation lithium source in the positive electrode Lithium ions are evolved, and the negative electrode is made to store lithium, thereby pre-lithiation of the negative electrode.
  7. 根据权利要求6所述的方法，其中，基于正极组合物的总干重，所述经预锂化或未预锂化的电池中的Li2C2的含量为大于0至约20重量％，优选大于0至小于20重量％，更优选约0.01重量％至约5重量％，再更优选约0.01重量％至约1重量％。The method according to claim 6, wherein the content of Li 2 C 2 in the pre-lithiated or unpre-lithiated battery is from more than 0 to about 20% by weight based on the total dry weight of the positive electrode composition. It is preferably from more than 0 to less than 20% by weight, more preferably from about 0.01% by weight to about 5% by weight, still more preferably from about 0.01% by weight to about 1% by weight.
  8. 根据权利要求6或7所述的方法，其中，除了在预锂化期间储存在所述负极中的锂元素之外，所述负极的可用于嵌入锂的不可逆容量(单位：mAh/cm2)是所述正极的不可逆容量(单位：mAh/cm2)的约1倍至约1.4倍，优选约1倍至约1.2倍，更优选约1倍至约1.1倍。The method according to claim 6 or 7, wherein the irreversible capacity (unit: mAh/cm 2 ) of the negative electrode usable for intercalating lithium is in addition to the lithium element stored in the negative electrode during prelithiation It is about 1 time to about 1.4 times, preferably about 1 time to about 1.2 times, more preferably about 1 time to about 1.1 times the irreversible capacity (unit: mAh/cm 2 ) of the positive electrode.
  9. 根据权利要求6-8中任一项所述的方法，其中，在将所述锂离子电池充电时，截止电压的上限不低于约3.8V但不高于约5V，优选不低于约4.2V但不高于约5V。The method according to any one of claims 6 to 8, wherein, when the lithium ion battery is charged, the upper limit of the cutoff voltage is not lower than about 3.8 V but not higher than about 5 V, preferably not lower than about 4.2. V is not higher than about 5V.
  10. 锂离子电池，其包含正极、负极和电解液，其中所述电解液包含锂盐、非水溶剂和选自以下的预锂化锂源：LiVO3、LiV3O8、Li3VO4、Li2C2以及它们的任意组合，优选Li2C2；A lithium ion battery comprising a positive electrode, a negative electrode and an electrolyte, wherein the electrolyte comprises a lithium salt, a non-aqueous solvent, and a pre-lithiation lithium source selected from the group consisting of LiVO 3 , LiV 3 O 8 , Li 3 VO 4 , Li 2 C 2 and any combination thereof, preferably Li 2 C 2 ;
    优选地，所述电解液还包含硼基阴离子受体。Preferably, the electrolyte further comprises a boron based anion acceptor.
  11. 制备根据权利要求10所述的锂离子电池的方法，所述方法包括以下步骤：A method of preparing a lithium ion battery according to claim 10, the method comprising the steps of:
    --提供电解液，所述电解液包含锂盐、非水溶剂和选自以下的预锂化锂源：LiVO3、LiV3O8、Li3VO4、Li2C2以及它们的任意组合，优选Li2C2；Providing an electrolyte comprising a lithium salt, a non-aqueous solvent, and a pre-lithiation lithium source selected from the group consisting of LiVO 3 , LiV 3 O 8 , Li 3 VO 4 , Li 2 C 2 , and any combination thereof , preferably Li 2 C 2 ;
    --将负极、正极和所述电解液组装成锂离子电池；以及任选地，- assembling the negative electrode, the positive electrode and the electrolyte into a lithium ion battery; and optionally,
    --将所述锂离子电池充电，从而使所述电解液中的预锂化锂源释放出锂离子，并且使所述负极储存锂，由此将所述负极预锂化。 - charging the lithium ion battery such that a lithium pre-lithiation source in the electrolyte releases lithium ions, and the anode is stored in lithium, thereby pre-lithiation of the anode.
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