WO2018045940A1 - Liquid active lithium supplement, preparation method therefor and use thereof - Google Patents

Liquid active lithium supplement, preparation method therefor and use thereof Download PDF

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Publication number
WO2018045940A1
WO2018045940A1 PCT/CN2017/100487 CN2017100487W WO2018045940A1 WO 2018045940 A1 WO2018045940 A1 WO 2018045940A1 CN 2017100487 W CN2017100487 W CN 2017100487W WO 2018045940 A1 WO2018045940 A1 WO 2018045940A1
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lithium
liquid active
supplement
ion battery
sulfide
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PCT/CN2017/100487
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French (fr)
Chinese (zh)
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詹元杰
黄学杰
俞海龙
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中国科学院物理研究所
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Publication of WO2018045940A1 publication Critical patent/WO2018045940A1/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
    • 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
    • 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
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the invention belongs to the field of lithium ion batteries.
  • the present invention relates to a liquid active lithium extender based on a lithium-based sulfide, and to a process for the preparation of the active lithium extender and use thereof.
  • Lithium-ion batteries are widely used in a variety of small portable electronic devices, such as notebook computers, mobile phones, and video cameras, due to their high discharge voltage, high energy density, and long cycle life.
  • High-tech fields such as aerospace satellites, electric vehicles, and military applications require lithium-ion batteries with better capacity and cycle life.
  • a solid electrolyte film (SEI film) is formed on the surface of the negative electrode material of the lithium ion battery, and along with the cycle of the lithium ion battery, the source The lithium ion of the active lithium in the positive electrode and the lithium ion in the electrolyte cannot be completely removed after being embedded in the negative electrode material.
  • the commercially available electrolyte is ethylene carbonate (EC), dimethyl carbonate (DMC), vinylene carbonate.
  • a carbonate-based electrolyte such as an ester (VC)
  • the main components of the SEI film are LiF, Li 2 CO 3 , and alkyl ester lithium, and the lithium ions in these products are mainly derived from active lithium in the positive electrode, which is inevitable. This will result in a decrease in the capacity of the lithium ion battery and a decrease in the cycle efficiency, especially after the first charge and discharge cycle, the cycle efficiency is more pronounced.
  • the Chinese Patent Publication No. CN1290209C discloses a method for lithium-receiving a negative electrode. After forming a slurry of metal lithium, a negative electrode material and a non-aqueous liquid, it is scraped onto a current collector, and a pole piece is formed through a subsequent process.
  • the method can also supplement the consumed active lithium, since the activity of the metal lithium is very high, it is easy to react with oxygen, water vapor and nitrogen in the air, so the whole process needs to be carried out under completely anhydrous conditions, and the process is cumbersome.
  • the production cost is greatly improved, and the lithium powder has a great safety hazard because it is easy to float in the air.
  • a method of "wet lithium supplementation” is disclosed.
  • the organic lithium is sprayed or dropped onto the surface of the positive electrode, and the lithium in the organic lithium is reduced and embedded in the positive electrode sheet.
  • the n-butyl lithium and t-butyl lithium used are high-flammable and explosive dangerous materials, and the safety is not higher than that of lithium powder; although the organic lithium sprayed on the surface of the positive electrode has a part.
  • the organic lithium is reduced and embedded in the positive electrode, but there are still many residues, which in turn will further reduce the capacity.
  • the present invention provides a liquid active lithium extender for supplementing active lithium in a lithium ion battery.
  • the active lithium supplement provided by the present invention is a sulfide of lithium dissolved or partially dissolved in a solvent. Therefore, the liquid active lithium supplement provided by the present invention can directly prepare small-sized lithium sulfide and can be uniformly mixed with carbon. The composite, and because the lithium sulfide is dispersed in the solvent, is easier to store.
  • the invention also provides a method of using the liquid active lithium supplement. Therefore, the liquid active lithium supplement provided by the invention is simple in preparation, low in cost and suitable for mass production, and can be widely applied to industrial production.
  • the present invention provides a liquid active lithium supplement for replenishing active lithium in a lithium ion battery, the liquid active lithium supplement being a solution or suspension, including a sulfide and a solvent of lithium;
  • the solvent is capable of dissolving or partially dissolving the sulfide of the lithium;
  • the solvent does not physically and/or chemically react with the electrolyte of the lithium ion battery; and/or
  • the solvent is selected from the electrolyte of the lithium ion battery.
  • the sulfide of lithium is selected from one or more of lithium sulfide, lithium persulfide, and lithium polysulfide. More preferably, the sulfide of lithium is lithium sulfide.
  • the sulfide of lithium may be synthesized in advance, or may be formed by mixing lithium sulfide and sulfur in a molar ratio of Li:S of 2:1 to 8 to the solvent as described above.
  • the molar concentration of lithium ions in the liquid active lithium extender is from 0.01 mol/L to 5 mol/L, more preferably from 0.01 mol/L to 0.5 mol/L, most preferably from 0.01 mol/L to 0.25. Mol/L.
  • the solvent is selected from one or more of organic solvents capable of dissolving lithium sulfide; more preferably, the solvent is selected from the group consisting of methanol, ethanol, tetraethylene glycol dimethyl ether (TEGDME) and two One or more of methyl ether (DME).
  • TEGDME tetraethylene glycol dimethyl ether
  • DME methyl ether
  • the liquid active lithium supplement further comprises an optional conductive additive and/or an optional binder;
  • the conductive additive is selected from one or more of a carbon black conductive agent, a conductive carbon tube, graphene or graphene oxide; more preferably, the carbon black conductive agent is selected from the group consisting of acetylene black, Super P, One or more of Super S, 350G, carbon fiber (VGCF), carbon nanotubes (CNTs), Ketjen black EC 300J, Ketjen black EC 600JD, Carbon ECP or Carbon ECP600JD; preferably, said The mass of the conductive additive in the liquid active lithium extender is from 0 to 50% by mass of the sulfide of the lithium; preferably from 5% to 20%; more preferably from 5% to 10%.
  • the binder is selected from the group consisting of polyvinylpyrrolidone (PVP), polyvinylidene fluoride (PVDF), polyethylene oxide (PEO), polytetrafluoroethylene (PTFE), and carboxymethyl cellulose (CMC).
  • PVP polyvinylpyrrolidone
  • PVDF polyvinylidene fluoride
  • PEO polyethylene oxide
  • PTFE polytetrafluoroethylene
  • CMC carboxymethyl cellulose
  • the mass of the binder in the liquid active lithium extender is from 0 to 20% by mass of the sulfide of the lithium; preferably from 2% to 10%; more preferably from 2% to 5%.
  • the electrolyte is selected from one or more of a liquid electrolyte, a solid electrolyte, a semi-solid electrolyte, and a polymer electrolyte.
  • the present invention provides a method of preparing the above liquid active lithium extender, the method comprising the steps of:
  • a lithium sulfide, an optional conductive additive, and an optional binder are added to the solvent to be mixed to obtain a liquid active lithium extender.
  • the addition is a one-time addition or a step-wise addition.
  • the present invention provides a method of replenishing active lithium in a lithium ion battery, the method comprising adding the above liquid active lithium supplement to a positive electrode material slurry of the lithium ion battery and/or incorporating To the positive electrode of the lithium ion battery and/or to the electrolyte of the lithium ion battery.
  • the active lithium supplement is added to the positive electrode material slurry and/or incorporated into the positive electrode;
  • the liquid active lithium extender is incorporated into the positive electrode using coating, dip and/or spray coating.
  • the active lithium supplement accounts for a mass percentage of the positive or positive electrode material 0.1-20%, preferably 2% to 10%, more preferably 2 to 5%.
  • the liquid active lithium extender is added to the electrolyte of the lithium ion battery when the solvent does not physically and/or chemically react with the electrolyte of the lithium ion battery.
  • the liquid active lithium supplement is added to the electrolyte of the lithium ion battery.
  • the present invention also provides a lithium ion battery comprising the liquid active lithium extender of the present invention.
  • the present invention also provides a method of preparing a lithium ion battery, the method comprising preparing a lithium ion battery using the liquid active lithium supplement described above, and/or preparing a lithium ion battery using the above method.
  • the inventors of the present invention have found that the active lithium supplement is added to the battery system in the form of a solution, which is fully decomposed during the first charge and discharge cycle, releasing lithium ions embedded or deposited on the negative electrode or alloyed with the negative electrode to make up the negative electrode.
  • the formation of the SEI film and the metal lithium lost during the subsequent cycle release excess active lithium, and the lithium consumed in the formation of the negative SEI film is replenished, and therefore, the inventors of the present invention use one or several solvents to dissolve or partially dissolve the activity.
  • the lithium extender obtains a liquid active lithium supplement and then adds it to the battery system, so that the first charge and discharge capacity and long cycle stability of the lithium ion battery are significantly improved. Therefore, the lithium ion secondary battery of the present invention can significantly improve energy density and service life.
  • the liquid active lithium supplement provided by the invention is simple to prepare, convenient to use, high in safety and low in cost. Further, the liquid active lithium supplement provided by the invention has good compatibility with various cathode materials, anode materials and electrolytes of the lithium ion battery, and can be used for preparing various lithium ion batteries, thereby improving the reversible charge and discharge capacity of the whole battery and Subsequent loop stability.
  • FIG. 1 is a cyclic voltammetry curve of a lithium ion battery (half battery) composed of a positive electrode tab D1 and a lithium sheet according to the present invention
  • FIG. 2 is a cyclic voltammetry curve of a lithium ion battery (half battery) composed of a positive electrode tab D3 and a lithium sheet according to the present invention
  • FIG. 3 is a comparison diagram of the first week charge and discharge curves of the full batteries F1 and F3 according to the present invention.
  • Li 2 S lithium sulfide
  • Super P 0.02g of PVP
  • Li 2 S lithium sulfide
  • Super P 0.02g of PVP
  • Li 2 S lithium sulfide
  • Super P 0.02g of PVP
  • Li 2 S lithium sulfide
  • Super P 0.09g
  • PVP polyvinyl sulfide
  • Li 2 S lithium sulfide
  • Super P 0.09g
  • PVP polyvinyl sulfide
  • A6 Li 2 S
  • Li 2 S lithium sulfide
  • Super P 0.04g of PVP
  • Li 2 S lithium sulfide
  • Super P 0.09g
  • PVP polyvinyl sulfide
  • Li 2 S lithium sulfide
  • PVP polyvinyl sulfide
  • Li 2 S lithium sulfide
  • S sulfur
  • S tetraethylene glycol dimethyl ether
  • B1 tetraethylene glycol dimethyl ether
  • Li 2 S lithium sulfide
  • DME dimethyl ether
  • Li 2 S lithium sulfide
  • S sulfur
  • S tetraethylene glycol dimethyl ether
  • B3 tetraethylene glycol dimethyl ether
  • Li 2 S lithium sulfide
  • S sulfur
  • DME dimethyl ether
  • Li 2 S lithium sulfide
  • S sulfur
  • S tetraethylene glycol dimethyl ether
  • B5 tetraethylene glycol dimethyl ether
  • Li 2 S lithium sulfide
  • S sulfur
  • DME dimethyl ether
  • Li 2 S lithium sulfide
  • S sulfur
  • S tetraethylene glycol dimethyl ether
  • B7 tetraethylene glycol dimethyl ether
  • Li 2 S lithium sulfide
  • S sulfur
  • DME dimethyl ether
  • Li 2 S lithium sulfide
  • TEGDME tetraethylene glycol dimethyl ether
  • Li 2 S lithium sulfide
  • DME dimethyl ether
  • This example was formulated for use as a comparative active lithium supplement according to the following procedure, which was carried out at room temperature:
  • Li 2 S lithium sulfide
  • Super P 0.02 g of PVP
  • Li 2 S lithium sulfide
  • PVP polyvinyl ether
  • Li 2 S lithium sulfide
  • Super P 0.18 g of lithium sulfide (Li 2 S) and 0.02 g of Super P were uniformly mixed in NMP to obtain an active lithium supplement, which was designated as C4.
  • LiFePO 4 is used as the positive electrode active material
  • carbon black is used as the conductive additive
  • carboxymethyl cellulose (CMC) copolymer of styrene and butadiene (SBR) is used as the binder, and the mass ratio is 90:7:1.
  • 2 Mix well in water to prepare a uniform positive electrode slurry.
  • a uniform positive electrode slurry was uniformly coated on an aluminum foil current collector having a thickness of 15 ⁇ m, and dried at 55 ° C to form a 100 ⁇ m thick pole piece, which was placed under a roll press (pressure was about 1 MPa ⁇ 1.5 cm 2 ). , cutting the pole piece into a diameter of The 14 mm disc was placed in a vacuum oven and baked at 120 ° C for 6 h. After natural cooling, it was taken out and placed in a glove box for use as a positive electrode tab, denoted as D1.
  • Graphite was used as the negative electrode active material, carbon black was used as the conductive additive, and carboxymethyl cellulose (CMC), copolymer of styrene and butadiene (SBR) was used as the binder, and the mass ratio was 93:2:2: 3 Mix well in water to prepare a uniform negative electrode slurry.
  • CMC carboxymethyl cellulose
  • SBR copolymer of styrene and butadiene
  • a uniform negative electrode slurry was uniformly coated on a copper foil current collector having a thickness of 8 ⁇ m, and dried at 55 ° C to form pole pieces of 50 ⁇ m and 59 ⁇ m thickness, which were placed under a roll press (pressure was about 1 MPa ⁇ 1.5cm2), cut the pole piece to a diameter of A 15 mm wafer was placed in a vacuum oven and baked at 120 ° C for 6 h. After natural cooling, it was taken out and placed in a glove box for use as a negative electrode tab.
  • a three-layer film of PP/PE/PP was used as a separator (purchased from Celegard, USA) between the positive electrode and the negative electrode, and 1 M LiPF6 was added dropwise to dissolve in EC/DMC (1:1, A non-aqueous electrolyte (available from BASF Electrolyte Company, Germany), a 50 ⁇ m graphite negative electrode sheet prepared in 4.1 as a negative electrode of the battery, and a D1 prepared in the step 4.1 as a positive electrode, and a button battery of the molding number CR2032.
  • EC/DMC A non-aqueous electrolyte (available from BASF Electrolyte Company, Germany)
  • a 50 ⁇ m graphite negative electrode sheet prepared in 4.1 as a negative electrode of the battery and a D1 prepared in the step 4.1 as a positive electrode
  • a button battery of the molding number CR2032. a button battery of the molding number CR2032.
  • the 59 ⁇ m graphite negative electrode sheet prepared in the step 4.1 was used as the negative electrode of the battery, and the D2-D17 prepared in the step 4.1 was used as the positive electrode, and the button type battery having the molding number CR2032 was assembled as F2 to F17.
  • the 59 ⁇ m graphite negative electrode sheet prepared in the step 4.1 was used as the negative electrode of the battery, and E1 to E4 prepared in the step 4.1 were used as the positive electrode, and the button type battery having the molding number CR2032 was assembled as G1 to G4.
  • a three-layer film of PP/PE/PP was used as a separator (purchased from Celegard, USA) between the positive electrode and the negative electrode, and 1 M LiPF6 was added dropwise to dissolve in EC/DMC (1:1, A non-aqueous electrolyte (volume purchased from BASF Electrolyte, Germany) was added to the electrolyte, and 30 ⁇ l of a B1-B10 solution was added to the electrolyte.
  • the 59 ⁇ m graphite negative electrode sheet prepared in the step 1 was used as the negative electrode of the battery, and the D1 prepared in the step 1 was used as the positive electrode, and the button type battery having the molded number CR2032 was designated as H1 to H10.
  • the prepared button batteries F1 to F17, G1 to G4 and H1 to H10 were allowed to stand at room temperature for 24 hours, and then a blue electric 11 battery charge and discharge tester (purchased from Wuhan Landian Electronics Co., Ltd.) was used.
  • the button cell prepared above was subjected to a charge and discharge cycle test.
  • the specific capacity of LiFePO4 was calculated to be 160 mAhg -1 , and it was cycled at a rate of 0.05 C for one week, and then continued to be cycled at a rate of 0.2 C for 100 weeks, wherein the charge and discharge voltage of the control battery was in the range of 2.5 V to 3.6 V.
  • the preparation parameters and results are shown in Tables 1 and 2.
  • Figure 3 shows the comparison of the first week charge and discharge curves of lithium-ion batteries F1 and F3. It can be seen that the lithium-ion battery F3 has a low potential compared to F1, and its first week's charge capacity reaches 174.8 mAhg . 1. This excess capacity contribution comes from the decomposition of lithium sulfide, and the discharge capacity of the first week of Example F3 is as high as 146.6 mAhg-1, and the capacity of 15.5 mAhg-1 is more than that of F1 of only 131.1 mAhg-1.
  • Lithium sulfide can be divided during the first charge and explain the release of lithium ions, which compensates for the loss of lithium ions when forming the SEI film on the surface of the negative electrode, compensates for the loss of lithium ions in the positive electrode material and the electrolyte, thereby significantly improving the reversible of the first week of the lithium ion battery. Discharge capacity.
  • Figure 4 shows the comparison of the first-period charge-discharge curves of lithium-ion batteries F1 and H2. It can be seen that lithium-ion battery H2 has a low potential compared to F1, and its first-cycle charge capacity reaches 162.1mAhg. -1 , this excess capacity contribution comes from the decomposition of lithium sulfide, and the discharge capacity of H2 in the first week is as high as 139 mAhg-1, and the capacity of about 10 mAhg-1 is more than that of F1 only 131.1 mAhg-1.
  • the lithium sulfide can be divided and explained during the first charge, which can compensate for the loss of lithium ions when forming the SEI film on the surface of the negative electrode, and compensate for the loss of lithium ions in the positive electrode material and the electrolyte, thereby significantly increasing the head of the lithium ion battery. Weekly reversible discharge capacity.
  • Table 1 compares the 100-percent capacity retention of lithium-ion batteries F1 to F17 and G1 to G4 with different parameters. It can be seen that the long-cycle stability of the battery containing lithium sulfide supplement has been significantly improved, indicating lithium sulfide.
  • the active lithium produced by the decomposition also continuously compensates for the active lithium depleted during the electrochemical cycle of the lithium ion battery in subsequent cycles.
  • the capacity retention ratio of the lithium ion batteries G1 to G4 and the capacity of the first week are much smaller than those of the lithium ion batteries F2 to F17, and when a solvent which does not dissolve lithium sulfide is used, the activity is low and cannot be fully exhibited. The loss of active lithium cannot be fully supplemented.
  • Table 2 compares the 100-percent capacity retention of lithium-ion batteries F1 and H1-H10 with different parameters. It can be seen that the reversible capacity and long-cycle stability of lithium-ion batteries containing liquid active lithium supplements have been extremely The large increase indicates that the active lithium produced by the decomposition of lithium sulfide continues to compensate for the loss of active lithium in the electrochemical cycle of the lithium ion battery in the subsequent cycle. In general, the lithium-recognition method provided by the present invention can significantly improve the reversible capacity and long cycle stability of a lithium ion battery.
  • Table 1 shows the variation of the discharge capacity of lithium-ion batteries F1 ⁇ F17 and G1 ⁇ G4 with different parameters with the number of cycles.
  • Table 2 shows the variation trend of the discharge capacity of lithium ion batteries F1 and H1 to H15 with different parameters with the number of cycles.

Abstract

Provided is a liquid active lithium supplement for supplementing a lithium ion battery with active lithium. The liquid active lithium supplement is a solution or a suspension, and comprises sulfides of lithium and a solvent. The solvent can dissolve or partially dissolve the sulfides of lithium; and/or the solvent does not physically and/or chemically react with electrolytes of the lithium ion battery; and/or the solvent is selected from the electrolytes of the lithium ion battery. Also provided are a method for supplementing a lithium ion battery with active lithium, and a lithium ion battery. The liquid active lithium supplement is simple to prepare and convenient to use, and has high safety and low costs. The liquid active lithium supplement has good compatibility with cathode materials, anode materials, and electrolytes of a lithium ion battery, and can be used for preparing lithium ion batteries, thereby improving the reversible charge and discharge capability and subsequent cyclic stability of all batteries.

Description

一种液态活性锂补充剂、其制备方法及其用途Liquid active lithium supplement, preparation method thereof and use thereof
本申请要求2016年9月8日提交的名称为“一种液态活性锂补充剂、其制备方法及其用途”，申请号为2016108094665的发明专利申请的优先权。The present application claims priority to the patent application filed on Sep. 8, 2016, entitled "A Liquid Active Lithium Replenisher, Its Preparation Method, and Its Use," the application number of which is incorporated herein by reference.
技术领域Technical field
本发明属于锂离子电池领域。具体地，本发明涉及一种基于锂的硫化物的液态活性锂补充剂，本发明还涉及所述活性锂补充剂的制备方法及其用途。The invention belongs to the field of lithium ion batteries. In particular, the present invention relates to a liquid active lithium extender based on a lithium-based sulfide, and to a process for the preparation of the active lithium extender and use thereof.
背景技术Background technique
由于锂离子电池具有高的放电电压、高的能量密度以及长的循环寿命等优点，现已广泛应用于各种小型的便携式电子设备中，如笔记本电脑、移动手机和摄影机等，并且也逐渐受到高科技领域的青睐，如航天卫星、电动汽车和军事等，这些应用中均要求锂离子电池具有更好的容量和循环寿命。Lithium-ion batteries are widely used in a variety of small portable electronic devices, such as notebook computers, mobile phones, and video cameras, due to their high discharge voltage, high energy density, and long cycle life. High-tech fields such as aerospace satellites, electric vehicles, and military applications require lithium-ion batteries with better capacity and cycle life.
本领域技术人员已知的是，在锂离子电池进行首次充放电循环时，锂离子电池的负极材料表面会形成一种固体电解质薄膜(SEI膜)，同时随着锂离子电池的循环过程，来源于正极的活性锂的锂离子和电解质中的锂离子在嵌入到负极材料后不能完全脱出，进一步地，现在商用的电解质为碳酸乙烯酯(EC)、碳酸二甲酯(DMC)、碳酸亚乙烯酯(VC)等碳酸酯类电解质，因此SEI膜的主要成分有LiF、Li2CO3和烷基酯锂等，而这些产物中的锂离子主要来源于正极中的活性锂，这些情况不可避免会导致锂离子电池的容量衰减以及循环效率降低，尤其是首次充放电循环后，循环效率降低更明显。It is known to those skilled in the art that when a lithium ion battery is subjected to a first charge and discharge cycle, a solid electrolyte film (SEI film) is formed on the surface of the negative electrode material of the lithium ion battery, and along with the cycle of the lithium ion battery, the source The lithium ion of the active lithium in the positive electrode and the lithium ion in the electrolyte cannot be completely removed after being embedded in the negative electrode material. Further, the commercially available electrolyte is ethylene carbonate (EC), dimethyl carbonate (DMC), vinylene carbonate. a carbonate-based electrolyte such as an ester (VC), and therefore the main components of the SEI film are LiF, Li 2 CO 3 , and alkyl ester lithium, and the lithium ions in these products are mainly derived from active lithium in the positive electrode, which is inevitable. This will result in a decrease in the capacity of the lithium ion battery and a decrease in the cycle efficiency, especially after the first charge and discharge cycle, the cycle efficiency is more pronounced.
为了补充在首次充电过程中形成SEI膜以及后续的长循环不可逆容量损失引起的活性锂的损失，需要在锂离子电池中补充活性锂，现有的专利文献中已报道了一些补充锂的方法。In order to supplement the loss of active lithium caused by the formation of the SEI film during the first charging process and the subsequent long-cycle irreversible capacity loss, it is necessary to supplement the active lithium in the lithium ion battery, and some methods for supplementing lithium have been reported in the prior patent documents.
公开号为CN1290209C的中国专利中公开了一种负极补锂的方法，将金属锂、负极材料和非水液体形成浆料后，刮涂到集流体上，再经后续的工序形成极片。该方法虽然也可以补充消耗的活性锂，但由于金属锂的活性非常高，极易与空气中的氧气、水汽及氮气发生反应，故整个过程需要在完全无水的条件下进行，过程繁琐，极大的提高了生产成本，且锂粉由于容易漂浮于空气中，存在很大的安全隐患。 The Chinese Patent Publication No. CN1290209C discloses a method for lithium-receiving a negative electrode. After forming a slurry of metal lithium, a negative electrode material and a non-aqueous liquid, it is scraped onto a current collector, and a pole piece is formed through a subsequent process. Although the method can also supplement the consumed active lithium, since the activity of the metal lithium is very high, it is easy to react with oxygen, water vapor and nitrogen in the air, so the whole process needs to be carried out under completely anhydrous conditions, and the process is cumbersome. The production cost is greatly improved, and the lithium powder has a great safety hazard because it is easy to float in the air.
申请号为CN201310070202.9的专利申请中提出了将含锂化合物的锂补充剂直接掺入正极材料中或直接涂覆到正极的表面，在其首次充放电循环的充电过程中这些锂补充剂会分解，提供活性锂，虽然其在一定程度上补充了活性锂，但是由于锂的硫化物电子绝缘的性质，其颗粒较大时电化学活性较小，在首次充放电循环的充电时并不能完全的使活性锂发挥出来，因此只有将锂的硫化物分散为小的颗粒时，首次充放电循环才有活性，但预先制备小颗粒的锂的硫化物如高能球磨的方法，较为复杂，这将极大的提高成本，且小颗粒的锂的硫化物活性较高，会很快与空气中的水汽发生反应变质，不易保存。In the patent application No. CN201310070202.9, it is proposed to directly incorporate a lithium compound containing lithium compound into the positive electrode material or directly onto the surface of the positive electrode, and these lithium supplements will be charged during the charging process of the first charge and discharge cycle. Decomposition, providing active lithium, although it supplements the active lithium to a certain extent, due to the nature of lithium sulfide electronic insulation, the electrochemical activity is small when the particles are large, and cannot be completely charged during the first charge and discharge cycle. The active lithium is exerted, so the first charge and discharge cycle is active only when the lithium sulfide is dispersed into small particles, but the method of preparing small particles of lithium sulfide such as high energy ball milling in advance is complicated. The cost is greatly increased, and the lithium sulfide of the small particles has a high activity, and will quickly react with the water vapor in the air to deteriorate and is difficult to store.
申请号为CN 201210350770.X的专利申请中公开了一种“湿法补锂”的方法，将有机锂喷洒或滴加与正极的表面，使有机锂中的锂被还原后嵌入到正极片中。但该发明存在一些问题，如所使用的正丁基锂、叔丁基锂等是高易燃易爆的危险品，安全性并不比锂粉高；虽然喷洒在正极表面的有机锂有部分的有机锂被还原并嵌入正极中，但还存在很多的残留，这反而会进一步降低容量。In the patent application No. CN 201210350770.X, a method of "wet lithium supplementation" is disclosed. The organic lithium is sprayed or dropped onto the surface of the positive electrode, and the lithium in the organic lithium is reduced and embedded in the positive electrode sheet. . However, there are some problems in the invention. For example, the n-butyl lithium and t-butyl lithium used are high-flammable and explosive dangerous materials, and the safety is not higher than that of lithium powder; although the organic lithium sprayed on the surface of the positive electrode has a part. The organic lithium is reduced and embedded in the positive electrode, but there are still many residues, which in turn will further reduce the capacity.
因此，当前需要一种用于在锂离子电池中补充活性锂的试剂和方法，以减少锂离子电池在充放电过程中的容量衰减，并提高其循环效率。Therefore, there is a need for a reagent and method for replenishing active lithium in a lithium ion battery to reduce the capacity decay of the lithium ion battery during charge and discharge and to increase its cycle efficiency.
发明内容Summary of the invention
为了弥补现有技术的不足，本发明提供了一种用于在锂离子电池中补充活性锂的液态活性锂补充剂。本发明提供的活性锂补充剂为溶解或部分地溶解于溶剂中的锂的硫化物，因此，本发明提供的液态活性锂补充剂可以直接制备出小颗粒的锂的硫化物且可与碳均匀的复合，并且由于该锂的硫化物分散在溶剂中，更易于保存。本发明还提供了所述液态活性锂补充剂的使用方法。因此，本发明提供的液态活性锂补充剂制备方法简单、成本低且可适于量产，可以广泛地应用于工业生产。In order to compensate for the deficiencies of the prior art, the present invention provides a liquid active lithium extender for supplementing active lithium in a lithium ion battery. The active lithium supplement provided by the present invention is a sulfide of lithium dissolved or partially dissolved in a solvent. Therefore, the liquid active lithium supplement provided by the present invention can directly prepare small-sized lithium sulfide and can be uniformly mixed with carbon. The composite, and because the lithium sulfide is dispersed in the solvent, is easier to store. The invention also provides a method of using the liquid active lithium supplement. Therefore, the liquid active lithium supplement provided by the invention is simple in preparation, low in cost and suitable for mass production, and can be widely applied to industrial production.
一方面，本发明提供了一种用于在锂离子电池中补充活性锂的液态活性锂补充剂，所述液态活性锂补充剂为溶液或悬浊液，包括锂的硫化物和溶剂；In one aspect, the present invention provides a liquid active lithium supplement for replenishing active lithium in a lithium ion battery, the liquid active lithium supplement being a solution or suspension, including a sulfide and a solvent of lithium;
其中，所述溶剂能够溶解或部分地溶解所述锂的硫化物；和/或Wherein the solvent is capable of dissolving or partially dissolving the sulfide of the lithium; and/or
所述溶剂与所述锂离子电池的电解质不发生物理和/或化学反应；和/或The solvent does not physically and/or chemically react with the electrolyte of the lithium ion battery; and/or
所述溶剂选自所述锂离子电池的电解质。The solvent is selected from the electrolyte of the lithium ion battery.
优选地，所述锂的硫化物选自硫化锂、过硫化锂、多硫化锂中的一种或多种。更优选地，所述锂的硫化物为硫化锂。Preferably, the sulfide of lithium is selected from one or more of lithium sulfide, lithium persulfide, and lithium polysulfide. More preferably, the sulfide of lithium is lithium sulfide.
优选地，所述锂的硫化物可以预先合成，或者可以通过将硫化锂和硫以Li：S为2：1～8的摩尔计量比混合加入如上所述的溶剂形成。 Preferably, the sulfide of lithium may be synthesized in advance, or may be formed by mixing lithium sulfide and sulfur in a molar ratio of Li:S of 2:1 to 8 to the solvent as described above.
优选地，所述液态活性锂补充剂中锂离子的摩尔浓度为0.01mol/L-5mol/L，更优选地为0.01mol/L-0.5mol/L，最优选地为0.01mol/L-0.25mol/L。Preferably, the molar concentration of lithium ions in the liquid active lithium extender is from 0.01 mol/L to 5 mol/L, more preferably from 0.01 mol/L to 0.5 mol/L, most preferably from 0.01 mol/L to 0.25. Mol/L.
优选地，所述溶剂与所述锂的硫化物之间不发生化学反应。优选地，所述溶剂选自可溶解锂的硫化物的有机溶剂中的一种或几种；更优选地，所述溶剂选自甲醇、乙醇、四乙二醇二甲醚(TEGDME)和二甲醚(DME)中的一种或多种。Preferably, no chemical reaction occurs between the solvent and the sulfide of the lithium. Preferably, the solvent is selected from one or more of organic solvents capable of dissolving lithium sulfide; more preferably, the solvent is selected from the group consisting of methanol, ethanol, tetraethylene glycol dimethyl ether (TEGDME) and two One or more of methyl ether (DME).
优选地，所述液态活性锂补充剂中还包括任选的导电添加剂和/或任选的粘结剂；Preferably, the liquid active lithium supplement further comprises an optional conductive additive and/or an optional binder;
优选地，所述导电添加剂选自炭黑导电剂、导电炭管、石墨烯或氧化石墨烯中的一种或多种；更优选地，所述炭黑导电剂选自乙炔黑、Super P、Super S、350G、碳纤维(VGCF)、碳纳米管(CNTs)、科琴黑(Ketjen black EC 300J、Ketjen black EC 600JD、Carbon ECP或Carbon ECP600JD)中的一种或多种；优选地，所述液态活性锂补充剂中导电添加剂的质量为所述锂的硫化物质量的0～50％；优选地为5％～20％；更优选地为5％～10％。优选地，所述粘结剂选自聚乙烯吡咯烷酮(PVP)、聚偏氟乙烯(PVDF)、聚环氧乙烷(PEO)、聚四氟乙烯(PTFE)、羧甲基纤维素(CMC)、苯乙烯与丁二烯的共聚物(SBR)中的一种或多种。优选地，所述液态活性锂补充剂中粘结剂的质量为所述锂的硫化物质量的0～20％；优选地为2％～10％；更优选地为2％～5％。Preferably, the conductive additive is selected from one or more of a carbon black conductive agent, a conductive carbon tube, graphene or graphene oxide; more preferably, the carbon black conductive agent is selected from the group consisting of acetylene black, Super P, One or more of Super S, 350G, carbon fiber (VGCF), carbon nanotubes (CNTs), Ketjen black EC 300J, Ketjen black EC 600JD, Carbon ECP or Carbon ECP600JD; preferably, said The mass of the conductive additive in the liquid active lithium extender is from 0 to 50% by mass of the sulfide of the lithium; preferably from 5% to 20%; more preferably from 5% to 10%. Preferably, the binder is selected from the group consisting of polyvinylpyrrolidone (PVP), polyvinylidene fluoride (PVDF), polyethylene oxide (PEO), polytetrafluoroethylene (PTFE), and carboxymethyl cellulose (CMC). One or more of a copolymer of styrene and butadiene (SBR). Preferably, the mass of the binder in the liquid active lithium extender is from 0 to 20% by mass of the sulfide of the lithium; preferably from 2% to 10%; more preferably from 2% to 5%.
优选地，所述电解质选自液态电解质、固态电解质、半固态电解质和聚合物电解质中的一种或多种。Preferably, the electrolyte is selected from one or more of a liquid electrolyte, a solid electrolyte, a semi-solid electrolyte, and a polymer electrolyte.
另一方面，本发明提供了上述液态活性锂补充剂的制备方法，所述方法包括以下步骤：In another aspect, the present invention provides a method of preparing the above liquid active lithium extender, the method comprising the steps of:
将锂的硫化物、任选的导电添加剂和任选的粘结剂添加到溶剂中混合以得到液态活性锂补充剂。A lithium sulfide, an optional conductive additive, and an optional binder are added to the solvent to be mixed to obtain a liquid active lithium extender.
优选地，所述添加为一次性全部添加或分步添加。Preferably, the addition is a one-time addition or a step-wise addition.
另一方面，本发明提供了一种在锂离子电池中补充活性锂的方法，所述方法包括将上述液态活性锂补充剂加入到所述锂离子电池的正极材料浆料中和/或掺入到所述锂离子电池的正极和/或加入到所述锂离子电池的电解质中。In another aspect, the present invention provides a method of replenishing active lithium in a lithium ion battery, the method comprising adding the above liquid active lithium supplement to a positive electrode material slurry of the lithium ion battery and/or incorporating To the positive electrode of the lithium ion battery and/or to the electrolyte of the lithium ion battery.
优选地，当所述溶剂与所述活性锂补充剂不发生物理和/或化学反应时，将所述活性锂补充剂加入正极材料浆料中和/或掺入正极；Preferably, when the solvent does not physically and/or chemically react with the active lithium supplement, the active lithium supplement is added to the positive electrode material slurry and/or incorporated into the positive electrode;
优选地，使用涂覆、浸蘸和/或喷涂的方式将所述液态活性锂补充剂掺入正极。优选地，所述活性锂补充剂占所述正极或正极材料的质量百分比为 0.1-20％，优选地为2％～10％，更优选地为2～5％。Preferably, the liquid active lithium extender is incorporated into the positive electrode using coating, dip and/or spray coating. Preferably, the active lithium supplement accounts for a mass percentage of the positive or positive electrode material 0.1-20%, preferably 2% to 10%, more preferably 2 to 5%.
优选地，当所述溶剂与所述锂离子电池的电解质不发生物理和/或化学反应时，将所述液态活性锂补充剂加入到所述锂离子电池的电解质中。Preferably, the liquid active lithium extender is added to the electrolyte of the lithium ion battery when the solvent does not physically and/or chemically react with the electrolyte of the lithium ion battery.
优选地，当所述溶剂选自所述锂离子电池的电解质时，将所述液态活性锂补充剂加入到所述锂离子电池的电解质中。Preferably, when the solvent is selected from the electrolyte of the lithium ion battery, the liquid active lithium supplement is added to the electrolyte of the lithium ion battery.
再另一方面，本发明还提供了一种锂离子电池，所述锂离子电池中包含本发明所述的液态活性锂补充剂。In still another aspect, the present invention also provides a lithium ion battery comprising the liquid active lithium extender of the present invention.
另一方面，本发明还提供了一种锂离子电池的制备方法，所述方法包括使用上述的液态活性锂补充剂来制备锂离子电池，和/或使用上述方法制备锂离子电池。In another aspect, the present invention also provides a method of preparing a lithium ion battery, the method comprising preparing a lithium ion battery using the liquid active lithium supplement described above, and/or preparing a lithium ion battery using the above method.
本发明的发明人发现，将活性锂补充剂以溶液的形式加入电池体系中，其在首次充放电循环时得到了充分的分解，释放锂离子嵌入或沉积于负极或与负极合金化，弥补负极形成SEI膜及后续循环过程中损耗的金属锂释放出多余的活性锂，负极SEI膜形成时消耗的锂得到了补充，因此，本发明的发明人使用一种或几种溶剂溶解或部分溶解活性锂补充剂得到液态活性锂补充剂，然后将其加入到电池体系中，使锂离子电池的首充放电容量和长循环稳定性都得到了显著的提高。因此本发明的锂离子二次电池，能显著提高能量密度和使用寿命。The inventors of the present invention have found that the active lithium supplement is added to the battery system in the form of a solution, which is fully decomposed during the first charge and discharge cycle, releasing lithium ions embedded or deposited on the negative electrode or alloyed with the negative electrode to make up the negative electrode. The formation of the SEI film and the metal lithium lost during the subsequent cycle release excess active lithium, and the lithium consumed in the formation of the negative SEI film is replenished, and therefore, the inventors of the present invention use one or several solvents to dissolve or partially dissolve the activity. The lithium extender obtains a liquid active lithium supplement and then adds it to the battery system, so that the first charge and discharge capacity and long cycle stability of the lithium ion battery are significantly improved. Therefore, the lithium ion secondary battery of the present invention can significantly improve energy density and service life.
基于此，本发明提供的液态活性锂补充剂制备简单，使用方便，安全性高，成本低廉。进一步地，本发明提供的液态活性锂补充剂与锂离子电池的各种正极材料、负极材料及电解质兼容性好，可以用于制备各种锂离子电池，从而提高全电池的可逆充放电容量及后续的循环稳定性。Based on this, the liquid active lithium supplement provided by the invention is simple to prepare, convenient to use, high in safety and low in cost. Further, the liquid active lithium supplement provided by the invention has good compatibility with various cathode materials, anode materials and electrolytes of the lithium ion battery, and can be used for preparing various lithium ion batteries, thereby improving the reversible charge and discharge capacity of the whole battery and Subsequent loop stability.
附图的简要说明BRIEF DESCRIPTION OF THE DRAWINGS
以下，结合附图来详细说明本发明的实施方案，其中：Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, in which:
图1为本发明所述的正极极片D1与锂片组成的锂离子电池(半电池)的循环伏安曲线；1 is a cyclic voltammetry curve of a lithium ion battery (half battery) composed of a positive electrode tab D1 and a lithium sheet according to the present invention;
图2为本发明所述的正极极片D3与锂片组成的锂离子电池(半电池)的循环伏安曲线；2 is a cyclic voltammetry curve of a lithium ion battery (half battery) composed of a positive electrode tab D3 and a lithium sheet according to the present invention;
图3为本发明所述的全电池F1与F3的首周充放电曲线对比图；3 is a comparison diagram of the first week charge and discharge curves of the full batteries F1 and F3 according to the present invention;
图4为本发明所述的全电池F1与H1的首周充放电曲线对比图；4 is a comparison diagram of the first week charge and discharge curves of the full batteries F1 and H1 according to the present invention;
实施发明的最佳方式The best way to implement the invention
下面结合具体实施方式对本发明进行进一步详细的描述，给出的实施例仅为阐明发明，而不是为了限制本发明的范围。 The present invention is further described in detail with reference to the preferred embodiments thereof.
实施例1 制备液态活性锂补充剂Example 1 Preparation of Liquid Active Lithium Replenisher
本实施例根据下述步骤配制液态活性锂补充剂，所述操作在室温下进行：This example prepares a liquid active lithium extender according to the following procedure, which is carried out at room temperature:
1.取0.16g硫化锂(Li2S)、0.02g Super P和0.02g PVP，将其置于20ml甲醇中，超声10h，再搅拌10h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为A1。1. Take 0.16g of lithium sulfide (Li 2 S), 0.02g of Super P and 0.02g of PVP, put it in 20ml of methanol, sonicate for 10h, then stir for 10h and mix evenly to obtain liquid active lithium supplement. The lithium supplement is referred to as A1.
2.取0.16g硫化锂(Li2S)、0.02g Super P和0.02g PVP，将其置于20ml乙醇中，超声10h，再搅拌10h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为A2。2. Take 0.16g of lithium sulfide (Li 2 S), 0.02g of Super P and 0.02g of PVP, put it in 20ml of ethanol, sonicate for 10h, then stir for 10h and mix evenly to obtain liquid active lithium supplement. The lithium supplement is denoted as A2.
3.取0.16g硫化锂(Li2S)、0.02g Super P和0.02g PVP，将其置于20mlTEGDME中，超声10h，再搅拌10h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为A3。3. Take 0.16g of lithium sulfide (Li 2 S), 0.02g of Super P and 0.02g of PVP, put it in 20ml TEGDME, sonicate for 10h, then stir for 10h and mix evenly to obtain liquid active lithium supplement, the liquid active lithium The supplement is recorded as A3.
4.取0.16g硫化锂(Li2S)、0.02g Super P和0.02g PVP，将其置于20ml DME中，超声10h，再搅拌10h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为A4。4. Take 0.16g of lithium sulfide (Li 2 S), 0.02g of Super P and 0.02g of PVP, place it in 20ml DME, sonicate for 10h, then stir for 10h and mix evenly to obtain liquid active lithium supplement. The lithium supplement is referred to as A4.
5.取0.08g硫化锂(Li2S)、0.09g Super P和0.04g PVP，将其置于20ml甲醇中，超声10h，再搅拌10h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为A5。5. Take 0.08g of lithium sulfide (Li 2 S), 0.09g of Super P and 0.04g of PVP, and place it in 20ml of methanol, sonicate for 10h, then stir for 10h and mix evenly to obtain liquid active lithium supplement. The lithium supplement is referred to as A5.
6.取0.08g硫化锂(Li2S)、0.09g Super P和0.04g PVP，将其置于20ml乙醇中，超声10h，再搅拌10h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为A6。6. Take 0.08g of lithium sulfide (Li 2 S), 0.09g of Super P and 0.04g of PVP, and place it in 20ml of ethanol, sonicate for 10h, then stir for 10h and mix evenly to obtain liquid active lithium supplement. The lithium supplement is referred to as A6.
7.取0.08g硫化锂(Li2S)、0.09g Super P和0.04g PVP，将其置于20ml TEGDME中，超声10h，再搅拌10h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为A7。7. Take 0.08g of lithium sulfide (Li 2 S), 0.09g of Super P and 0.04g of PVP, and place it in 20ml of TEGDME, sonicate for 10h, then stir for 10h and mix evenly to obtain liquid active lithium supplement. The lithium supplement is referred to as A7.
8.取0.08g硫化锂(Li2S)、0.09g Super P和0.04g PVP，将其置于20ml DME中，超声10h，再搅拌10h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为A8。8. Take 0.08g of lithium sulfide (Li 2 S), 0.09g of Super P and 0.04g of PVP, and place it in 20ml of DME, sonicate for 10h, then stir for 10h and mix evenly to obtain liquid active lithium supplement. The lithium supplement is referred to as A8.
9.取0.18g硫化锂(Li2S)和0.02g PVP，将其置于20ml甲醇中，超声10h，再搅拌10h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为A9。9. Take 0.18g of lithium sulfide (Li 2 S) and 0.02g of PVP, put it in 20ml of methanol, sonicate for 10h, then stir for 10h and mix evenly to obtain liquid active lithium supplement. The liquid active lithium supplement is recorded as A9.
10.取0.18g硫化锂(Li2S)和0.02g PVP，将其置于20ml乙醇中，超声10h，再搅拌10h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为A10。10. Take 0.18g of lithium sulfide (Li 2 S) and 0.02g of PVP, put it in 20ml of ethanol, sonicate for 10h, then stir for 10h and mix evenly to obtain liquid active lithium supplement. The liquid active lithium supplement is recorded as A10.
11.取0.18g硫化锂(Li2S)和0.02g PVP，将其置于20ml TEGDME中，超声10h，再搅拌10h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为A11。 11. Take 0.18g of lithium sulfide (Li 2 S) and 0.02g of PVP, put it in 20ml TEGDME, sonicate for 10h, then stir for 10h and mix evenly to obtain liquid active lithium supplement. The liquid active lithium supplement is recorded as A11.
12.取0.18g硫化锂(Li2S)和0.02g PVP，将其置于20ml DME中，超声10h，再搅拌10h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为A12。12. Take 0.18g of lithium sulfide (Li 2 S) and 0.02g of PVP, put it in 20ml DME, sonicate for 10h, then stir for 10h and mix evenly to obtain liquid active lithium supplement. The liquid active lithium supplement is recorded as A12.
13.取0.18g硫化锂(Li2S)和0.02g Super P，将其置于20ml甲醇中，超声10h，再搅拌10h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为A13。13. Take 0.18g of lithium sulfide (Li 2 S) and 0.02g of Super P, put it in 20ml of methanol, sonicate for 10h, then stir for 10h and mix evenly to obtain liquid active lithium supplement, the liquid active lithium supplement For A13.
14.取0.18g硫化锂(Li2S)和0.02g Super P，将其置于20ml乙醇中，超声10h，再搅拌10h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为A14。14. Take 0.18g of lithium sulfide (Li 2 S) and 0.02g of Super P, put it in 20ml of ethanol, sonicate for 10h, then stir for 10h and mix evenly to obtain liquid active lithium supplement, the liquid active lithium supplement For A14.
15.取0.18g硫化锂(Li2S)和0.02g Super P，将其置于20ml TEGDME中，超声10h，再搅拌10h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为A15。15. Take 0.18g of lithium sulfide (Li 2 S) and 0.02g of Super P, put it in 20ml TEGDME, sonicate for 10h, then stir for 10h and mix evenly, then get liquid active lithium supplement, the liquid active lithium supplement For A15.
16.取0.18g硫化锂(Li2S)和0.02g Super P，将其置于20ml DME中，超声10h，再搅拌10h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为A16。16. Take 0.18g of lithium sulfide (Li 2 S) and 0.02g of Super P, put it in 20ml DME, sonicate for 10h, then stir for 10h and mix evenly to obtain liquid active lithium supplement, the liquid active lithium supplement For A16.
实施例2 制备液态活性锂补充剂Example 2 Preparation of Liquid Active Lithium Replenisher
本实施例根据下述步骤配制液态活性锂补充剂，所述操作在室温下进行：This example prepares a liquid active lithium extender according to the following procedure, which is carried out at room temperature:
1.取0.0115g硫化锂(Li2S)和0.056g硫(S)，将其置于四乙二醇二甲醚(TEGDME)中，搅拌6h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为B1。1. Take 0.0115g of lithium sulfide (Li 2 S) and 0.056g of sulfur (S), put it in tetraethylene glycol dimethyl ether (TEGDME), and mix it evenly for 6h to obtain liquid active lithium supplement. The liquid active lithium supplement is referred to as B1.
2.取0.0115g硫化锂(Li2S)和0.056g硫(S)，将其置于二甲醚(DME)中，搅拌6h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为B2。2. Take 0.0115g of lithium sulfide (Li 2 S) and 0.056g of sulfur (S), put it in dimethyl ether (DME), stir evenly for 6h, then obtain liquid active lithium supplement, the liquid active lithium supplement The agent is recorded as B2.
3.取0.0115g硫化锂(Li2S)和0.048g硫(S)，将其置于四乙二醇二甲醚(TEGDME)中，搅拌6h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为B3。3. Take 0.0115g of lithium sulfide (Li 2 S) and 0.048g of sulfur (S), put it in tetraethylene glycol dimethyl ether (TEGDME), and mix it evenly for 6h to obtain liquid active lithium supplement. The liquid active lithium supplement is referred to as B3.
4.取0.0115g硫化锂(Li2S)和0.048g硫(S)，将其置于二甲醚(DME)中，搅拌6h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为B4。4. Take 0.0115g of lithium sulfide (Li 2 S) and 0.048g of sulfur (S), put it in dimethyl ether (DME), stir evenly for 6h, then obtain liquid active lithium supplement, the liquid active lithium supplement The agent is recorded as B4.
5.取0.0115g硫化锂(Li2S)和0.032g硫(S)，将其置于四乙二醇二甲醚(TEGDME)中，搅拌6h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为B5。5. Take 0.0115g of lithium sulfide (Li 2 S) and 0.032g of sulfur (S), put it in tetraethylene glycol dimethyl ether (TEGDME), and mix it evenly for 6h to obtain liquid active lithium supplement. The liquid active lithium supplement is referred to as B5.
6.取0.0115g硫化锂(Li2S)和0.032g硫(S)，将其置于二甲醚(DME)中，搅拌6h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为B6。6. Take 0.0115g of lithium sulfide (Li 2 S) and 0.032g of sulfur (S), put it in dimethyl ether (DME), stir evenly for 6h, then obtain liquid active lithium supplement, the liquid active lithium supplement The agent is recorded as B6.
7.取0.0115g硫化锂(Li2S)和0.024g硫(S)，将其置于四乙二醇二甲 醚(TEGDME)中，搅拌6h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为B7。7. Take 0.0115g of lithium sulfide (Li 2 S) and 0.024g of sulfur (S), put it in tetraethylene glycol dimethyl ether (TEGDME), and mix it evenly for 6h to obtain liquid active lithium supplement. The liquid active lithium supplement is referred to as B7.
8.取0.0115g硫化锂(Li2S)和0.024g硫(S)，将其置于二甲醚(DME)中，搅拌6h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为B8。8. Take 0.0115g of lithium sulfide (Li 2 S) and 0.024g of sulfur (S), put it in dimethyl ether (DME), stir evenly for 6h, then obtain liquid active lithium supplement, the liquid active lithium supplement The agent is recorded as B8.
9.取0.0115g硫化锂(Li2S)，将其置于四乙二醇二甲醚(TEGDME)中，搅拌6h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为B9。9. Take 0.0115g of lithium sulfide (Li 2 S), put it in tetraethylene glycol dimethyl ether (TEGDME), and mix it evenly for 6h to obtain liquid active lithium supplement. The liquid active lithium supplement is recorded as B9.
10.取0.0115g硫化锂(Li2S)，将其置于二甲醚(DME)中，搅拌6h均匀混合，即得液态活性锂补充剂，该液态活性锂补充剂记为B10。10. Take 0.0115 g of lithium sulfide (Li 2 S), place it in dimethyl ether (DME), and mix it evenly for 6 hours to obtain a liquid active lithium supplement. The liquid active lithium supplement is denoted as B10.
实施例3 对比例Example 3 Comparative Example
本实施例根据下述步骤配制用作对比活性锂补充剂，所述操作在室温下进行：This example was formulated for use as a comparative active lithium supplement according to the following procedure, which was carried out at room temperature:
取0.16g硫化锂(Li2S)、0.02g Super P和0.02g PVP，在NMP中均匀混合，即得活性锂补充剂，该活性锂补充剂记为C1。0.16 g of lithium sulfide (Li 2 S), 0.02 g of Super P and 0.02 g of PVP were uniformly mixed in NMP to obtain an active lithium extender, which was designated as C1.
取0.08g硫化锂(Li2S)、0.09g Super P和0.04g PVP，在NMP中均匀混合，即得活性锂补充剂，该活性锂补充剂记为C2。0.08 g of lithium sulfide (Li 2 S), 0.09 g of Super P and 0.04 g of PVP were uniformly mixed in NMP to obtain an active lithium supplement, which was designated as C2.
取0.18g硫化锂(Li2S)和0.02g PVP，在NMP中均匀混合，即得活性锂补充剂，该活性锂补充剂记为C3。0.18 g of lithium sulfide (Li 2 S) and 0.02 g of PVP were uniformly mixed in NMP to obtain an active lithium supplement, which was designated as C3.
取0.18g硫化锂(Li2S)和0.02g Super P，在NMP中均匀混合，即得活性锂补充剂，该活性锂补充剂记为C4。0.18 g of lithium sulfide (Li 2 S) and 0.02 g of Super P were uniformly mixed in NMP to obtain an active lithium supplement, which was designated as C4.
实施例4 性能测试Example 4 Performance Test
将实施例1中配制的溶液A1～A16按照如下的步骤装配成扣式电池。The solutions A1 to A16 prepared in Example 1 were assembled into a button cell in accordance with the following procedure.
4.1正极极片和负极极片的制备4.1 Preparation of positive and negative pole pieces
将LiFePO4作为正极活性材料，炭黑作为导电添加剂，以羧甲基纤维素(CMC)、苯乙烯与丁二烯的共聚物(SBR)为粘结剂，按照质量比为90:7:1:2在水中混合均匀，制备成均匀的正极浆料。将均匀的正极浆料均匀涂覆在厚度为15μm的铝箔集流体上，在55℃下烘干，形成100μm厚的极片，置于辊压机下辊压(压力约为1MPa×1.5cm2),将极片裁剪成直径为
Figure PCTCN2017100487-appb-000001
14mm的圆片，置于真空烘箱中以120℃烘6h，自然冷却后，取出，置于手套箱中用作正极极片，记为D1。LiFePO 4 is used as the positive electrode active material, carbon black is used as the conductive additive, and carboxymethyl cellulose (CMC), copolymer of styrene and butadiene (SBR) is used as the binder, and the mass ratio is 90:7:1. : 2 Mix well in water to prepare a uniform positive electrode slurry. A uniform positive electrode slurry was uniformly coated on an aluminum foil current collector having a thickness of 15 μm, and dried at 55 ° C to form a 100 μm thick pole piece, which was placed under a roll press (pressure was about 1 MPa × 1.5 cm 2 ). , cutting the pole piece into a diameter of
Figure PCTCN2017100487-appb-000001
The 14 mm disc was placed in a vacuum oven and baked at 120 ° C for 6 h. After natural cooling, it was taken out and placed in a glove box for use as a positive electrode tab, denoted as D1.
将石墨作为负极活性材料，炭黑作为导电添加剂，以羧甲基纤维素(CMC)、苯乙烯与丁二烯的共聚物(SBR)为粘结剂，按照质量比为93:2:2:3在水中混合均匀，制备成均匀的负极浆料。将均匀的负极浆料均匀涂覆在厚度为8μm的铜箔集流体上，在55℃下烘干，形成50μm和59μm厚的极片，置 于辊压机下辊压(压力约为1MPa×1.5cm2)，将极片裁剪成直径为
Figure PCTCN2017100487-appb-000002
15mm的圆片，置于真空烘箱中以120℃烘6h，自然冷却后，取出置于手套箱中用作负极极片。Graphite was used as the negative electrode active material, carbon black was used as the conductive additive, and carboxymethyl cellulose (CMC), copolymer of styrene and butadiene (SBR) was used as the binder, and the mass ratio was 93:2:2: 3 Mix well in water to prepare a uniform negative electrode slurry. A uniform negative electrode slurry was uniformly coated on a copper foil current collector having a thickness of 8 μm, and dried at 55 ° C to form pole pieces of 50 μm and 59 μm thickness, which were placed under a roll press (pressure was about 1 MPa × 1.5cm2), cut the pole piece to a diameter of
Figure PCTCN2017100487-appb-000002
A 15 mm wafer was placed in a vacuum oven and baked at 120 ° C for 6 h. After natural cooling, it was taken out and placed in a glove box for use as a negative electrode tab.
在充满惰性气氛的手套箱中，取50μlA1～A4、80μlA5～A8和50μl的A9～A16的溶液滴至
Figure PCTCN2017100487-appb-000003
14mm的正极圆片上。在120℃下烘10h，自然冷却后，用作正极，记做D2-D17。取与A1、A5、A9和A13对应的活性锂补充剂同样质量的C1～C4涂覆与
Figure PCTCN2017100487-appb-000004
14mm的正极圆片上。在120℃下烘10h，自然冷却后，用作正极，记做E1～E4In a glove box filled with an inert atmosphere, take 50 μl of A1～A4, 80 μl of A5～A8 and 50 μl of A9～A16 solution to the solution.
Figure PCTCN2017100487-appb-000003
14mm positive electrode disc. After baking at 120 ° C for 10 h, it was used as a positive electrode after being naturally cooled, and it was designated as D2-D17. The same quality C1 ~ C4 coating with the active lithium supplement corresponding to A1, A5, A9 and A13
Figure PCTCN2017100487-appb-000004
14mm positive electrode disc. Bake at 120 ° C for 10 h, after natural cooling, used as a positive electrode, recorded as E1 ~ E4
4.2装配锂离子二次电池4.2 Assembly of lithium ion secondary battery
在充满惰性气氛的手套箱中，以PP/PE/PP的三层膜作为隔膜(购自美国Celegard公司)放在正极和负极之间，滴加1M LiPF6溶解在EC/DMC(1：1，体积比)的非水系电解质(购自德国巴斯夫电解质公司)，以4.1中制备的50μm的石墨负极极片作为电池的负极，以步骤4.1制备的D1作为正极，装配成型号为CR2032的扣式电池记做F1。以步骤4.1制备的59μm的石墨负极极片作为电池的负极，以步骤4.1制备的D2-D17作为正极，装配成型号为CR2032的扣式电池记做F2～F17。以步骤4.1制备的59μm的石墨负极极片作为电池的负极，以步骤4.1制备的E1～E4作为正极，装配成型号为CR2032的扣式电池记做G1～G4。In a glove box filled with an inert atmosphere, a three-layer film of PP/PE/PP was used as a separator (purchased from Celegard, USA) between the positive electrode and the negative electrode, and 1 M LiPF6 was added dropwise to dissolve in EC/DMC (1:1, A non-aqueous electrolyte (available from BASF Electrolyte Company, Germany), a 50 μm graphite negative electrode sheet prepared in 4.1 as a negative electrode of the battery, and a D1 prepared in the step 4.1 as a positive electrode, and a button battery of the molding number CR2032. Remember to be F1. The 59 μm graphite negative electrode sheet prepared in the step 4.1 was used as the negative electrode of the battery, and the D2-D17 prepared in the step 4.1 was used as the positive electrode, and the button type battery having the molding number CR2032 was assembled as F2 to F17. The 59 μm graphite negative electrode sheet prepared in the step 4.1 was used as the negative electrode of the battery, and E1 to E4 prepared in the step 4.1 were used as the positive electrode, and the button type battery having the molding number CR2032 was assembled as G1 to G4.
在充满惰性气氛的手套箱中，以PP/PE/PP的三层膜作为隔膜(购自美国Celegard公司)放在正极和负极之间，滴加1M LiPF6溶解在EC/DMC(1：1，体积比)的非水系电解质(购自德国巴斯夫电解质公司)，再往该电解质中加入30μlB1-B10的溶液。以步骤①制备的59μm的石墨负极极片作为电池的负极，以步骤①制备的D1为正极，装配成型号为CR2032的扣式电池记做H1～H10。In a glove box filled with an inert atmosphere, a three-layer film of PP/PE/PP was used as a separator (purchased from Celegard, USA) between the positive electrode and the negative electrode, and 1 M LiPF6 was added dropwise to dissolve in EC/DMC (1:1, A non-aqueous electrolyte (volume purchased from BASF Electrolyte, Germany) was added to the electrolyte, and 30 μl of a B1-B10 solution was added to the electrolyte. The 59 μm graphite negative electrode sheet prepared in the step 1 was used as the negative electrode of the battery, and the D1 prepared in the step 1 was used as the positive electrode, and the button type battery having the molded number CR2032 was designated as H1 to H10.
将制备的扣式电池F1～F17、G1～G4和H1～H10在室温条件下静置24个小时后，采用蓝电11电池充放电测试仪(购自武汉市蓝电电子股份有限公司)对上述制备的扣式电池进行充放电循环测试。首先将LiFePO4的比容量算为160mAhg-1，以0.05C的倍率循环1周，然后以0.2C的倍率继续循环100周，其中，控制电池的充放电电压范围为2.5V-3.6V。制备参数及结果详见表一和表二。The prepared button batteries F1 to F17, G1 to G4 and H1 to H10 were allowed to stand at room temperature for 24 hours, and then a blue electric 11 battery charge and discharge tester (purchased from Wuhan Landian Electronics Co., Ltd.) was used. The button cell prepared above was subjected to a charge and discharge cycle test. First, the specific capacity of LiFePO4 was calculated to be 160 mAhg -1 , and it was cycled at a rate of 0.05 C for one week, and then continued to be cycled at a rate of 0.2 C for 100 weeks, wherein the charge and discharge voltage of the control battery was in the range of 2.5 V to 3.6 V. The preparation parameters and results are shown in Tables 1 and 2.
结果result
从图1的循环伏安曲线上，显示了磷酸铁锂的氧化还原峰，而图2可以明显看出2.6V左右出现了一个氧化峰，显示了锂补充剂在首周充电的过程中在2.6V附近开始分解。 From the cyclic voltammetry curve of Figure 1, the redox peak of lithium iron phosphate is shown, while Figure 2 shows that an oxidation peak appears around 2.6V, indicating that the lithium supplement was charged during the first week of charging at 2.6. Decomposition begins near V.
图3中显示了锂离子电池F1和F3的首周充放电曲线对比，从中可以看出锂离子电池F3相较于F1有一个低电位的容量，且其首周的充电容量达到了174.8mAhg-1，这多余了容量贡献来自于硫化锂的分解，且实施例F3的首周的放电容量高达146.6mAhg-1，相对于F1的仅131.1mAhg-1多出了15.5mAhg-1的容量，说明硫化锂在首次充电时能够发生分并解释放锂离子，弥补了负极表面形成SEI膜时锂离子的损耗，补偿正极材料和电解质中的锂离子损耗，从而显著提高了锂离子电池的首周可逆放电容量。Figure 3 shows the comparison of the first week charge and discharge curves of lithium-ion batteries F1 and F3. It can be seen that the lithium-ion battery F3 has a low potential compared to F1, and its first week's charge capacity reaches 174.8 mAhg . 1. This excess capacity contribution comes from the decomposition of lithium sulfide, and the discharge capacity of the first week of Example F3 is as high as 146.6 mAhg-1, and the capacity of 15.5 mAhg-1 is more than that of F1 of only 131.1 mAhg-1. Lithium sulfide can be divided during the first charge and explain the release of lithium ions, which compensates for the loss of lithium ions when forming the SEI film on the surface of the negative electrode, compensates for the loss of lithium ions in the positive electrode material and the electrolyte, thereby significantly improving the reversible of the first week of the lithium ion battery. Discharge capacity.
图4中显示了锂离子电池F1和H2的首周充放电曲线对比，从中可以看出锂离子电池H2相较于F1的有一个低电位的容量，且其首周的充电容量达到了162.1mAhg-1，这多余了容量贡献来自于锂的硫化物的分解，且H2的首周的放电容量高达139mAhg-1，相对于F1的仅131.1mAhg-1多出了约10mAhg-1的容量，说明锂的硫化物在首次充电时能够发生分并解释放锂离子，弥补了负极表面形成SEI膜时锂离子的损耗，补偿正极材料和电解质中的锂离子损耗，从而显著提高了锂离子电池的首周可逆放电容量。Figure 4 shows the comparison of the first-period charge-discharge curves of lithium-ion batteries F1 and H2. It can be seen that lithium-ion battery H2 has a low potential compared to F1, and its first-cycle charge capacity reaches 162.1mAhg. -1 , this excess capacity contribution comes from the decomposition of lithium sulfide, and the discharge capacity of H2 in the first week is as high as 139 mAhg-1, and the capacity of about 10 mAhg-1 is more than that of F1 only 131.1 mAhg-1. The lithium sulfide can be divided and explained during the first charge, which can compensate for the loss of lithium ions when forming the SEI film on the surface of the negative electrode, and compensate for the loss of lithium ions in the positive electrode material and the electrolyte, thereby significantly increasing the head of the lithium ion battery. Weekly reversible discharge capacity.
表一中对比了不同参数的锂离子电池F1～F17和G1～G4的100周容量保持率可以看出，含有硫化锂补充剂的电池的长循环稳定性得到了显著的提高，说明了硫化锂分解产生的活性锂在后续的循环中也持续的补偿了锂离子电池在电化学循环过程中损耗的活性锂。但锂离子电池G1～G4的容量保持率和首周的容量相对于锂离子电池F2～F17要小的多，说明使用不溶解锂的硫化物的溶剂时，其活性较低不能全部发挥出来，不能完全补充活性锂的损失。Table 1 compares the 100-percent capacity retention of lithium-ion batteries F1 to F17 and G1 to G4 with different parameters. It can be seen that the long-cycle stability of the battery containing lithium sulfide supplement has been significantly improved, indicating lithium sulfide. The active lithium produced by the decomposition also continuously compensates for the active lithium depleted during the electrochemical cycle of the lithium ion battery in subsequent cycles. However, the capacity retention ratio of the lithium ion batteries G1 to G4 and the capacity of the first week are much smaller than those of the lithium ion batteries F2 to F17, and when a solvent which does not dissolve lithium sulfide is used, the activity is low and cannot be fully exhibited. The loss of active lithium cannot be fully supplemented.
表二中对比了不同参数的锂离子电池F1、H1～H10的100周容量保持率，从中可以看出，含液态活性锂补充剂的锂离子电池的可逆容量和长循环稳定性都得到了极大的提高，说明了硫化锂分解产生的活性锂在后续的循环中也持续的补偿了锂离子电池在电化学循环过程中损耗的活性锂。总的来说，含有本发明提供的补锂方法可以显著的提高锂离子电池的可逆容量和长的循环稳定性。 Table 2 compares the 100-percent capacity retention of lithium-ion batteries F1 and H1-H10 with different parameters. It can be seen that the reversible capacity and long-cycle stability of lithium-ion batteries containing liquid active lithium supplements have been extremely The large increase indicates that the active lithium produced by the decomposition of lithium sulfide continues to compensate for the loss of active lithium in the electrochemical cycle of the lithium ion battery in the subsequent cycle. In general, the lithium-recognition method provided by the present invention can significantly improve the reversible capacity and long cycle stability of a lithium ion battery.
表1为不同参数的锂离子电池F1～F17和G1～G4的放电容量随循环次数的变化趋势Table 1 shows the variation of the discharge capacity of lithium-ion batteries F1～F17 and G1～G4 with different parameters with the number of cycles.
Figure PCTCN2017100487-appb-000005
Figure PCTCN2017100487-appb-000005
表2为不同参数的锂离子电池F1、H1～H15的放电容量随循环次数的变化趋势。Table 2 shows the variation trend of the discharge capacity of lithium ion batteries F1 and H1 to H15 with different parameters with the number of cycles.
Figure PCTCN2017100487-appb-000006
Figure PCTCN2017100487-appb-000006
最后应说明的是：以上各实施例仅用于说明本发明的技术方案，而非对其限制；尽管参照前述各实施例对本发明进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本发明各实施例技术方案的范围。 It should be noted that the above embodiments are merely illustrative of the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that The technical solutions described in the foregoing embodiments may be modified, or some or all of the technical features may be equivalently replaced; and the modifications or substitutions do not deviate from the technical solutions of the embodiments of the present invention. range.

Claims (9)

  1. 一种用于在锂离子电池中补充活性锂的液态活性锂补充剂，所述液态活性锂补充剂为溶液或悬浊液，包括锂的硫化物和溶剂；A liquid active lithium supplement for replenishing active lithium in a lithium ion battery, the liquid active lithium supplement being a solution or a suspension, including a sulfide and a solvent of lithium;
    其中，所述溶剂能够溶解或部分地溶解所述锂的硫化物；和/或Wherein the solvent is capable of dissolving or partially dissolving the sulfide of the lithium; and/or
    所述溶剂与所述锂离子电池的电解质不发生物理和/或化学反应；和/或The solvent does not physically and/or chemically react with the electrolyte of the lithium ion battery; and/or
    所述溶剂选自所述锂离子电池的电解质。The solvent is selected from the electrolyte of the lithium ion battery.
  2. 根据权利要求1所述的液态活性锂补充剂，其中，所述锂的硫化物选自硫化锂、过硫化锂、多硫化锂中的一种或多种；The liquid active lithium supplement according to claim 1, wherein the sulfide of lithium is one or more selected from the group consisting of lithium sulfide, lithium persulfide, and lithium polysulfide;
    优选地，所述锂的硫化物为硫化锂；Preferably, the sulfide of lithium is lithium sulfide;
    优选地，所述锂离子的摩尔浓度为0.01mol/L-5mol/L，更优选地为0.01mol/L-0.5mol/L，最优选地为0.01mol/L-0.25mol/L。Preferably, the molar concentration of the lithium ions is from 0.01 mol/L to 5 mol/L, more preferably from 0.01 mol/L to 0.5 mol/L, and most preferably from 0.01 mol/L to 0.25 mol/L.
  3. 根据权利要求1或2所述的液态活性锂补充剂，其中，所述溶剂与所述锂的硫化物之间不发生化学反应；The liquid active lithium extender according to claim 1 or 2, wherein a chemical reaction does not occur between the solvent and the sulfide of the lithium;
    优选地，所述溶剂选自可溶解锂的硫化物的有机溶剂中的一种或几种；更优选地，所述溶剂选自甲醇、乙醇、四乙二醇二甲醚和二甲醚中的一种或多种。Preferably, the solvent is selected from one or more of organic solvents capable of dissolving lithium sulfide; more preferably, the solvent is selected from the group consisting of methanol, ethanol, tetraethylene glycol dimethyl ether and dimethyl ether. One or more.
  4. 根据权利要求1-3中任一项所述的液态活性锂补充剂，其中，所述液态活性锂补充剂中还包括任选的导电添加剂和/或任选的粘结剂；The liquid active lithium supplement according to any one of claims 1 to 3, wherein the liquid active lithium supplement further comprises an optional conductive additive and/or an optional binder;
    优选地，所述导电添加剂选自炭黑导电剂、导电炭管、石墨烯和氧化石墨烯中的一种或多种；更优选地，所述炭黑导电剂选自乙炔黑、Super P、Super S、350G、碳纤维、碳纳米管、科琴黑中的一种或多种；Preferably, the conductive additive is selected from one or more of a carbon black conductive agent, a conductive carbon tube, graphene and graphene oxide; more preferably, the carbon black conductive agent is selected from the group consisting of acetylene black, Super P, One or more of Super S, 350G, carbon fiber, carbon nanotube, and Ketchen Black;
    优选地，所述科琴黑选自KetjenblackEC300J、KetjenblackEC600JD、Carbon ECP和Carbon ECP600JD中的一种或多种；Preferably, the ketjen black is selected from one or more of Ketjenblack EC300J, Ketjenblack EC600JD, Carbon ECP and Carbon ECP600JD;
    优选地，所述液态活性锂补充剂中导电添加剂的质量为所述锂的硫化物质量的0～50％；优选地为5％～20％；更优选地为5％～10％；优选地，所述粘结剂选自聚乙烯吡咯烷酮、聚偏氟乙烯、聚环氧乙烷、聚四氟乙烯、羧甲基纤维素、苯乙烯与丁二烯的共聚物中的一种或多种；优选地，所述液态活性锂补充剂中粘结剂的质量为所述锂的硫化物质量的0～20％；优选地为2％～10％；更优选地为2％～5％。Preferably, the mass of the conductive additive in the liquid active lithium extender is 0-50% of the mass of the sulfide of the lithium; preferably 5%-20%; more preferably 5%-10%; preferably The binder is selected from one or more of polyvinylpyrrolidone, polyvinylidene fluoride, polyethylene oxide, polytetrafluoroethylene, carboxymethyl cellulose, and a copolymer of styrene and butadiene. Preferably, the mass of the binder in the liquid active lithium extender is from 0 to 20% by mass of the sulfide of the lithium; preferably from 2% to 10%; more preferably from 2% to 5%.
  5. 根据权利要求1-4中任一项所述的液态活性锂补充剂，其中，所述电解质选自液态电解质、固态电解质、半固态电解质和聚合物电解质中的一种或多种。The liquid active lithium extender according to any one of claims 1 to 4, wherein the electrolyte is selected from one or more of a liquid electrolyte, a solid electrolyte, a semi-solid electrolyte, and a polymer electrolyte.
  6. 根据权利要求1-5中任一项所述的液态活性锂补充剂的制备方法，所述方法包括以下步骤： A method of preparing a liquid active lithium extender according to any one of claims 1 to 5, the method comprising the steps of:
    将锂的硫化物、任选的导电添加剂和任选的粘结剂添加到溶剂中混合以得到所述液态活性锂补充剂；Adding a sulfide of lithium, an optional conductive additive, and an optional binder to a solvent to obtain the liquid active lithium supplement;
    优选地，所述添加为一次性全部添加或分步添加。Preferably, the addition is a one-time addition or a step-wise addition.
  7. 一种在锂离子电池中补充活性锂的方法，所述方法包括将权利要求1-5中任一项所述的液态活性锂补充剂加入到所述锂离子电池的正极材料浆料中和/或掺入到所述锂离子电池的正极和/或加入到所述锂离子电池的电解质中。A method of replenishing active lithium in a lithium ion battery, the method comprising adding the liquid active lithium supplement according to any one of claims 1 to 5 to a positive electrode material slurry of the lithium ion battery and/ Or incorporated into the positive electrode of the lithium ion battery and/or added to the electrolyte of the lithium ion battery.
  8. 如权利要求7所述的方法，其中，当所述溶剂与所述活性锂补充剂不发生物理和/或化学反应时，将所述液态活性锂补充剂加入正极材料浆料中和/或掺入正极；The method of claim 7 wherein said liquid active lithium extender is added to and/or incorporated in the positive electrode material slurry when said solvent does not physically and/or chemically react with said reactive lithium extender Into the positive electrode;
    优选地，使用涂覆、浸蘸和/或喷涂的方式将所述液态活性锂补充剂掺入正极；Preferably, the liquid active lithium supplement is incorporated into the positive electrode using coating, dipping and/or spraying;
    优选地，所述液态活性锂补充剂占所述正极或正极材料的质量百分比为0.1-20％，优选地为2％～10％，更优选地为2～5％；Preferably, the liquid active lithium supplement accounts for 0.1-20% by mass of the positive electrode or cathode material, preferably 2% to 10%, more preferably 2 to 5%;
    优选地，当所述溶剂与所述锂离子电池的电解质不发生物理和/或化学反应时，将所述液态活性锂补充剂加入到所述锂离子电池的电解质中；Preferably, when the solvent does not physically and/or chemically react with the electrolyte of the lithium ion battery, the liquid active lithium supplement is added to the electrolyte of the lithium ion battery;
    优选地，当所述溶剂选自所述锂离子电池的电解质时，将所述液态活性锂补充剂加入到所述锂离子电池的电解质中。Preferably, when the solvent is selected from the electrolyte of the lithium ion battery, the liquid active lithium supplement is added to the electrolyte of the lithium ion battery.
  9. 一种锂离子电池，所述锂离子电池包含权利要求1-5中任一项所述的液态活性锂补充剂。 A lithium ion battery comprising the liquid active lithium extender of any one of claims 1 to 5.
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