WO2020215474A1 - 一种锂金属负极及其制备方法和使用该负极的锂电池 - Google Patents

一种锂金属负极及其制备方法和使用该负极的锂电池 Download PDF

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WO2020215474A1
WO2020215474A1 PCT/CN2019/092437 CN2019092437W WO2020215474A1 WO 2020215474 A1 WO2020215474 A1 WO 2020215474A1 CN 2019092437 W CN2019092437 W CN 2019092437W WO 2020215474 A1 WO2020215474 A1 WO 2020215474A1
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lithium
negative electrode
lithium metal
paste
metal negative
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PCT/CN2019/092437
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English (en)
French (fr)
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崔言明
刘张波
许晓雄
黄园桥
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浙江锋锂新能源科技有限公司
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Priority to EP19926643.8A priority Critical patent/EP3961760A1/en
Priority to US17/604,517 priority patent/US20220216483A1/en
Priority to AU2019442202A priority patent/AU2019442202B2/en
Priority to JP2021555869A priority patent/JP7210768B2/ja
Priority to CA3133847A priority patent/CA3133847C/en
Priority to KR1020217028779A priority patent/KR20210132078A/ko
Publication of WO2020215474A1 publication Critical patent/WO2020215474A1/zh

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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
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/661—Metal or alloys, e.g. alloy coatings
    • 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
    • H01M10/0568—Liquid materials characterised by the solutes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0569—Liquid materials characterised by the solvents
    • 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
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0404—Methods of deposition of the material by coating on electrode collectors
    • H—ELECTRICITY
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    • 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
    • H01M4/134—Electrodes based on metals, Si or alloys
    • 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
    • H01M4/1395—Processes of manufacture of electrodes based on metals, Si or alloys
    • 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
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
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    • 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
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/381—Alkaline or alkaline earth metals elements
    • H01M4/382—Lithium
    • 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
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    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
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    • 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
    • H01M2004/027—Negative 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
    • 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
    • H01M2300/0042—Four or more solvents
    • 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
    • H01M2300/0048—Molten electrolytes used at high temperature
    • H01M2300/0051—Carbonates
    • 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 relates to a lithium battery, in particular to a lithium metal negative electrode, a preparation method thereof, and a lithium battery using the negative electrode.
  • lithium-ion batteries Since Sony developed commercial lithium-ion batteries using graphite anodes as a mechanism for intercalation reactions, lithium-ion batteries have developed rapidly. However, commercial lithium-ion batteries with graphite as the negative electrode are difficult to meet the requirements for long battery life. Since the development of lithium-ion batteries, lithium metal negative electrodes with ten times the theoretical capacity of traditional graphite negative electrodes and lower minimum negative potential have become The current hot research direction of lithium metal batteries.
  • the energy density and current density of lithium metal batteries that have been successfully applied in the existing market are relatively small.
  • the Paris car-sharing service "Autolib” uses nearly 4,000 Bluecars. This is the first time in the world that it has been used in EV (Electric Vehicle).
  • the energy density of commercial lithium metal batteries for automobiles is only 170 wh/kg, and in order to increase the operating current, the operating temperature of the lithium metal batteries must be as high as 80°C.
  • the reasons for restricting the promotion of lithium metal batteries with high energy and high power density include: due to the limited lithium deposition sites on the surface of the existing lithium metal anodes, the local current is relatively large, and the lithium metal batteries are in the process of charging and discharging, especially large currents.
  • the surface of the lithium metal negative electrode is not uniformly deposited with lithium, which is easy to produce lithium dendrites.
  • the lithium dendrites will also pierce the separator, causing battery failure or safety problems, and some of the dendrites will detach and become unusable. "Dead lithium", resulting in a decrease in the Coulomb effect.
  • the growth of lithium dendrites on the lithium metal negative electrode is suppressed, and the main concern is to form a more stable lithium metal/electrolyte interface or use a physical barrier to laminate dendritic growth.
  • the above methods only work at low areal capacity densities (0.5- 1.0 mAh/cm 2 ) and low current density ( ⁇ 0.5 mA/cm 2 ) can play an effective role, but the effect is limited when facing the preparation and research of high-energy, high-power density batteries.
  • the conventional lithium metal foil negative electrode provides limited electron/ion reaction area during the discharge process, and cannot withstand a larger current discharge, which limits the upper limit of energy power and energy density of the lithium metal battery; the conventional lithium metal foil negative electrode In the process of lithium metal battery charge and discharge cycle, it is accompanied by great expansion and contraction, which is not conducive to the high cycle stability of lithium metal foil negative electrode and its application in solid-state batteries. Conventional lithium metal foil negative electrode is due to high activity and extension.
  • the conventional lithium metal negative electrode does not have any absorption effect on the electrolyte, and the electrolyte is excessively absorbed by the positive electrode during long-term storage, resulting in uneven distribution of the electrolyte in the battery, which is not conducive to Battery storage and high temperature performance.
  • the above-mentioned problems have caused the current situation where the promotion of lithium metal batteries with high energy and high power density is restricted.
  • the first object of the present invention is to provide a lithium metal negative electrode, which greatly improves the areal capacity and electron/ion reaction area of the lithium metal negative electrode, thereby improving the high-energy performance of the lithium metal battery. It meets the high energy and high power density requirements of lithium metal batteries.
  • a lithium metal negative electrode includes a current collector and a lithium paste layer covering one side of the current collector.
  • the current collector is an inert conductive material.
  • the lithium paste layer is coated with a paste-like lithium paste.
  • the lithium paste includes The following mass parts of raw materials are mixed:
  • the volume equivalent diameter of the lithium powder is 1-30 ⁇ m
  • the electrolyte is prepared by mixing a lithium salt and an organic solvent, the concentration of the lithium salt in the electrolyte is 0.5 mol/L-5 mol/L, and the organic solvent does not react with lithium powder or lithium salt.
  • the lithium paste obtained by mixing lithium powder particles with high specific surface area, thickener and electrolyte is uniformly covered on the surface of the current collector to form a lithium paste layer.
  • the lithium powder particles in the lithium paste layer serve as the negative electrode during discharge.
  • Electron-loss materials, lithium powder particles are evenly dispersed in the lithium paste by being wrapped by thickener and electrolyte, and the lithium powder particles have a high dispersion density, which greatly increases the surface capacity and electron/ion reaction area of the lithium metal negative electrode. Further improve the high-energy performance of lithium metal batteries and meet the high-energy and high-power density requirements of lithium metal batteries;
  • the lithium powder particles and the lithium powder particles are not fixed to each other.
  • the lithium powder particles are based on the distribution of the lithium powder particles and the size of the lithium powder particles.
  • Accumulation, ablation, and the local current distribution of the lithium metal negative electrode are adapted to move, change the distribution, and then increase the lithium deposition site during charging of the lithium metal battery using the lithium metal negative electrode of the present application, and reduce the local current density of the lithium metal negative electrode , Thereby reducing the growth rate of lithium dendrites, thereby slowing down the reduction in coulombic efficiency of the lithium metal negative electrode of this application after long-term use, and improving the cycle efficiency and safety performance of the lithium metal battery using the lithium metal negative electrode of this application;
  • the existing lithium metal negative electrode will expand and contract due to lithium metal deposition/precipitation, which will damage the cycle stability of the lithium metal negative electrode.
  • the lithium metal negative electrode Expansion and contraction will also destroy the bond between the lithium metal negative electrode and the solid electrolyte, and reduce the cycle efficiency of the lithium metal solid battery.
  • the lithium paste layer is obtained by covering the current collector with lithium paste, and the lithium paste includes thickener, liquid electrolyte and non-fixed lithium powder particles, so that the lithium paste layer has deformability and good fluidity.
  • the lithium paste layer can be deformed during the charging and discharging cycle of the lithium metal battery to buffer, slow down the expansion and contraction, and improve the cycle stability of the lithium metal negative electrode.
  • the lithium paste layer and the solid electrolyte can maintain good Contact to improve the application effect of the lithium metal negative electrode of the present application in the lithium metal solid state battery and facilitate the popularization and use of the lithium metal solid state battery.
  • the fluidity of the lithium paste layer enables the lithium metal negative electrode of the present application to avoid the thin thickness of the lithium foil during the ultra-thin processing of the existing lithium foil negative electrode.
  • the thickness of the lithium paste layer is thin and controllable, which improves production efficiency, reduces production costs, and improves the mass energy density and volume energy density of the lithium metal battery using the lithium metal anode of the application ;
  • the lithium powder particles and thickener in the lithium paste have a certain ability to retain the electrolyte, which can ensure the infiltration and contact of the electrolyte with the lithium metal during storage, and prevent the electrolyte from being damaged by the lithium metal battery during long-term storage.
  • the excessive absorption of the positive electrode promotes the uniform distribution of the electrolyte in the battery and improves the storage performance of the lithium metal battery.
  • the lithium salt is LiN(SO 2 CF3) 2 , LiNO 3 , LiAsF 6 , LiPF 6 , LiI, LiBF 4 , LiClO 4 , LiSO 2 CF 3 , LiB(C 2 O 4 ) 2 One or more of.
  • the organic solvent is propylene carbonate, ethylene carbonate, fluoroethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, 1,3-dioxolane, carbonic acid One or more of dimethyl sulfoxide, dimethyl sulfoxide and tetrahydrofuran.
  • the organic solvent is used as the carrier for dissolving and dispersing the lithium salt, and at the same time as the film-forming aid of the lithium paste, which improves the film-forming properties of the lithium paste and facilitates the ultra-thin processing of the lithium paste layer.
  • the organic solvent is used as the carrier for dissolving and dispersing the lithium salt, and at the same time as the film-forming aid of the lithium paste, which improves the film-forming properties of the lithium paste and facilitates the ultra-thin processing of the lithium paste layer.
  • metal batteries more battery cell numbers, stacking times or winding times per unit mass or unit volume are obtained to improve the mass energy density and volume energy density of the lithium metal battery using the lithium metal anode of the application; and where fluorine
  • the addition of ethylene carbonate can also inhibit the decomposition of electrolyte, reduce interface impedance, and increase the energy power of lithium metal batteries.
  • the thickener contains one or more of fumed silica, organic bentonite, polyethylene wax, polyamide wax or hydrogenated castor oil.
  • the above thickener can increase the consistency of the electrolyte, prevent the sedimentation of lithium powder particles, and avoid the separation of lithium paste, and the addition of the above thickener can also modify the surface of the lithium powder particles in situ. Improve the compatibility of lithium powder particles with organic solvents and promote uniform dispersion of lithium powder particles in the lithium paste.
  • the present invention is further configured that: the thickness of the lithium paste layer is 5-60 ⁇ m.
  • the processing thickness of the lithium paste layer is thin, which can reduce the production cost, and is beneficial to improve the mass energy density and volume energy density of the lithium metal battery using the lithium metal negative electrode of the present application.
  • the second object of the present invention is to provide a method for preparing a lithium metal negative electrode to ensure that the lithium powder is uniformly mixed in the lithium paste and prevent the lithium paste from separating and separating.
  • a preparation method of lithium metal negative electrode includes the following steps:
  • the lithium paste preparation process in the lithium metal negative electrode preparation method is carried out in two steps. First, the electrolyte and the thickener are mixed to obtain viscous liquid A, and then the viscous liquid A is mixed with lithium powder. After adding viscous liquid A during the stirring process, the lithium powder particles are wrapped and protected by the viscous liquid A, which buffers the collision between the lithium powder particles or between the lithium powder particles and the stirring equipment, and reduces the lithium powder particles in the stirring process. The probability of rupture maintains the integrity of the lithium powder particles, and the viscous liquid A with greater viscosity prevents the lithium powder particles from settling during mixing, so that the lithium powder is uniformly mixed in the lithium paste, and prevents the lithium paste from separating and separating.
  • the present invention is further configured that: the S4 stirring process is performed in a vacuum environment with a vacuum pressure of 10-10 -4 Pa.
  • the lithium powder is added to the viscous liquid A and stirred to make it easy to stir and dissolve gas in the viscous liquid A, and the tiny bubbles and dissolved gases contained in the viscous liquid A are removed in a vacuum environment ,
  • the tiny bubbles and dissolved gases contained in the viscous liquid A are removed in a vacuum environment ,
  • Steps S1-S5 are all completed in a dry atmosphere, and the water dew point in the dry atmosphere is less than -10°C.
  • the lithium paste is prevented from being damp during the preparation process of the lithium paste, and the water content in the lithium paste is prevented from reducing the coulombic efficiency of the lithium metal battery and causing potential safety hazards.
  • the third object of the present invention is to provide a battery with good charge-discharge cycle performance, good charge-discharge cycle performance, high energy and high power density.
  • a lithium metal battery which is a liquid or solid lithium metal battery, and includes the above-mentioned lithium metal negative electrode.
  • the present invention has the following beneficial effects:
  • the lithium powder particles with high specific surface area, thickener and electrolyte are mixed to obtain a lithium paste, which is uniformly coated on the surface of the current collector material to form a lithium paste layer.
  • the lithium powder particles in the lithium paste layer are used as electron-loss materials when the negative electrode is discharged.
  • the lithium powder particles are wrapped by thickener and electrolyte and dispersed evenly in the lithium paste with high dispersion density, which greatly increases the surface capacity and electron/ion reaction area of the lithium metal negative electrode, thereby increasing the high energy of the lithium metal battery Performance meets the high energy and high power density requirements of lithium metal batteries;
  • the lithium powder particles and the lithium powder particles are not fixed to each other.
  • the lithium powder particles can move in the lithium paste layer according to the distribution of the lithium powder particles in the lithium paste layer and the size of the lithium powder particles, thereby improving the charging time of the lithium metal battery Lithium deposition sites of the lithium metal negative electrode, and reduce the local current density of the lithium metal negative electrode, thereby reducing the growth rate of lithium dendrites, thereby slowing down the reduction of the coulombic efficiency of the lithium metal negative electrode of the present application after long-term use, and improving the use of the lithium of the present application
  • the lithium paste layer has deformability, which can buffer the deformation during the charging and discharging cycle of the lithium metal battery, improve the cycle stability of the lithium metal negative electrode, and when used in the lithium metal solid battery, the lithium paste layer and the solid electrolyte can Maintain good contact to improve the application effect of the lithium metal negative electrode of the present application in lithium metal solid-state batteries and facilitate the popularization and use of lithium metal solid-state batteries;
  • the lithium paste has good fluidity and improves the processability of the lithium paste.
  • the thickness of the lithium paste layer obtained by the coating is thin and controllable, which improves production efficiency, reduces production costs, and improves the use of lithium metal in the lithium metal anode of the application.
  • the lithium powder particles and the thickener in the lithium paste have a certain liquid retention capacity for the electrolyte, which can ensure the electrolyte infiltration and contact with the lithium metal during storage, and prevent the electrolyte from being caused by the lithium metal battery during long-term storage. Excessive absorption of the positive electrode to promote the uniform distribution of the electrolyte in the battery and improve the storage performance of the lithium metal battery;
  • the method of obtaining lithium paste is carried out in two steps. First, the electrolyte and the thickener are mixed to obtain viscous liquid A, and then viscous liquid A is mixed with lithium powder to reduce the lithium powder particles in the stirring process The probability of rupture in the medium, to ensure that the lithium powder is evenly mixed in the lithium paste, and to prevent the separation of the lithium paste;
  • the lithium metal battery has good cycle stability, high energy density and high power density.
  • a lithium metal negative electrode includes a current collector and a lithium paste layer covering the current collector.
  • the current collector is an inert conductive material, which can be determined according to actual conditions.
  • it is preferably copper foil with a thickness of 8 ⁇ m.
  • the lithium paste layer is directly obtained by coating a paste-like lithium paste, and the thickness of the lithium paste layer is 5-60 ⁇ m.
  • Lithium paste includes the following mass parts of raw materials mixed together:
  • the morphology of the lithium powder is granular, flake or needle-like, and its volume equivalent diameter is 1-30 ⁇ m, that is, the maximum volume equivalent diameter of lithium powder particles is 30 ⁇ m.
  • the thickener is one or more of fumed silica, organic bentonite, polyethylene wax, polyamide wax or hydrogenated castor oil.
  • the electrolyte is prepared by mixing lithium salt and organic solvent, wherein the concentration of lithium salt is 0.5 mol/L-5 mol/L.
  • the lithium salt is LiN(SO 2 CF 3 ) 2 (LiTFSI for short), LiNO 3 , LiAsF 6 , LiPF 6 , LiI, LiBF 4 , LiClO 4 , LiSO 2 CF 3 , LiB(C 2 O 4 ) 2 (LiBOB for short)
  • One or more of the organic solvents are propylene carbonate (abbreviated as PC), ethylene carbonate (abbreviated as EC), fluoroethylene carbonate (abbreviated as FEC), diethyl carbonate (abbreviated as DEC), dimethyl carbonate (Abbreviated as DMC), ethyl methyl carbonate (abbreviated as EMC), 1,3-dioxolane (abbreviated as DOL), ethylene glycol dimethyl ether (abbreviated as DME), dimethyl
  • the preparation method of the foregoing lithium metal negative electrode is as follows:
  • a lithium metal negative electrode the steps of the preparation method are the same as those in Example 1, and the lithium metal negative electrodes of Examples 1A-1F are obtained.
  • the specific parameters are shown in Table 2.
  • a lithium metal battery which is a liquid lithium metal battery, includes the lithium metal negative electrode of the first embodiment.
  • the preparation method of the lithium metal battery is as follows:
  • X2 Assemble other parts and casing to obtain a lithium metal battery.
  • a lithium metal battery is a liquid lithium metal battery and includes the lithium metal negative electrode of the second embodiment.
  • the preparation method of the lithium metal battery is as follows:
  • X1 To the side of the lithium metal negative electrode with the lithium paste layer obtained in Example 1, a laminated solid electrolyte membrane and a positive electrode are sequentially attached to obtain a battery core;
  • X2 Assemble other parts and casing to obtain a lithium metal battery.
  • the solid electrolyte is the prior art, and here the solid electrolyte is made into a thin film by pressing and sintering or shaping, etc., here is the LLZO solid electrolyte membrane.
  • a lithium metal battery is an existing liquid lithium metal battery.
  • the current collector is a copper foil with a thickness of 8 ⁇ m
  • the negative electrode is a lithium foil with a thickness of 100 ⁇ m
  • LiTFSI/EC-DMC is used as the electrolyte.
  • the PE-PP-PE diaphragm paper and the NCM positive electrode are combined, and subsequent assembly is continued to obtain a comparative example One lithium metal battery.
  • a lithium metal battery, the preparation method is as follows:
  • a lithium foil with a thickness of 100 ⁇ m was used as a negative electrode, and its two sides were attached with an LLZO solid electrolyte membrane and a copper foil with a thickness of 8 ⁇ m. After the NCM positive electrode was combined, the subsequent assembly was continued to obtain the lithium metal negative battery of Comparative Example 2. .
  • Example 3 The batteries obtained in Example 3, Example 4, Comparative Example 1 and Comparative Example 2 were tested using a battery tester (commercial product of Shenzhen Newwell Electronics Co., Ltd.), and the test results are shown in Table 5.
  • the liquid lithium metal battery prepared by the lithium metal negative electrode of the present application can adjust the thickness of the lithium paste layer compared with the existing liquid lithium metal battery using lithium foil as the negative electrode.
  • the energy density of the lithium metal battery can be adjusted according to design requirements to obtain a lithium metal battery with high energy density; at the same time, the lithium metal battery prepared in Example 1 is better than the existing liquid lithium metal battery using lithium foil as the negative electrode , Its coulombic efficiency, energy power and cycle stability show a significant improvement.
  • the solid lithium metal battery prepared by the lithium metal negative electrode of the present application is better than the existing solid lithium metal battery using lithium foil as the negative electrode.
  • the lithium metal negative electrode of this application has a more obvious effect on improving the energy density of the lithium metal battery, and for the existing solid-state lithium metal battery that uses lithium foil as the negative electrode, this application’s
  • the lithium metal negative electrode also shows a significant improvement in the coulombic efficiency, energy power and cycle stability of the prepared lithium metal battery.
  • a lithium metal battery is based on Example 3A. The difference lies in that the electrolyte, thickener and lithium powder are simultaneously added and mixed in a method for preparing a lithium metal negative electrode.
  • a lithium metal battery which is based on Example 3A, with the difference that the S4 stirring process in a method for preparing a lithium metal negative electrode is performed under normal pressure.
  • a lithium metal battery is based on Example 3A. The difference is that the preparation process of a lithium metal negative electrode is prepared in an environment with a relative humidity of 80%.
  • a lithium metal battery is based on Example 3A.
  • the difference lies in the composition of the thickener.
  • the specific composition parameters are shown in Table 6.
  • Example 8C Thickener Hydroxypropylmethylcellulose Sodium Alginate Xanthan gum
  • Example 5 to Example 7 and Comparative Example 3 were tested using a battery tester (commercial product of Shenzhen Newwell Electronics Co., Ltd.), and the test results are shown in Table 7.
  • Example 3A in Table 4 Comparing the data of Example 3A in Table 4 with the data of Example 5 in Table 7, the battery energy density, average coulombic efficiency, cycle life, and highest stable current of the battery of Example 3A are better than those of Example 5. This is because the lithium paste is prepared first. Mix the electrolyte with the thickener to obtain a viscous liquid A, and then mix the viscous liquid A with the lithium powder to avoid sedimentation and agglomeration of the lithium powder particles during mixing, and reduce the morphological damage caused by the stirring of the lithium powder during the mixing process.
  • Example 3 Lithium The cycle stability, energy density and energy power performance of lithium metal batteries with metal anodes.
  • Example 3A Comparing the data of Example 3A in Table 4 with the data of Example 6 in Table 7, the battery energy density, average coulombic efficiency, and cycle life of Example 3A are better than those of Example 6.
  • the lithium metal negative electrode is produced in a vacuum environment, which reduces The mixed microbubbles and the amount of dissolved gas in the lithium paste can improve the performance of improving the cycle stability, energy density and energy power of the lithium metal battery using the lithium metal negative electrode of the present application.
  • Comparative Example 3 the lithium metal negative electrode prepared in a humid environment cannot be used after being assembled into a battery. Therefore, the preparation of the lithium paste in a dry atmosphere can prevent the lithium paste from being damp and improve the manufacture of the lithium metal battery in this application. Yield rate, reduce production products, and prevent safety hazards.
  • Example 3A in Table 4 Comparing the data of Example 3A in Table 4 with the data of Example 7 in Table 7, the battery energy density, average Coulomb efficiency, and cycle life of Example 3A are better than those of Example 7.
  • fumed silica One or more of organobentonite, polyethylene wax, polyamide wax or hydrogenated castor oil, in addition to improving the consistency of the electrolyte, preventing the sedimentation of lithium particles, and the separation of the lithium paste, it can also affect the surface of the lithium powder particles. Carry out in-situ modification to promote uniform dispersion of lithium powder particles in the lithium paste and improve battery performance.
  • a lithium metal battery is based on Comparative Example 2. The difference lies in the thickness of the lithium foil used as the negative electrode during the preparation process.
  • lithium metal batteries were prepared by using lithium foils of different thicknesses to obtain Comparative Examples 4A-4E.
  • the thickness of the lithium foil and the yield of the lithium negative electrode are shown in Table 8.
  • the thickness of the lithium foil is less than 100 ⁇ m, the thickness deviation of the obtained lithium foil increases, and it is difficult to assemble during the assembly process. Also, due to the activity and ductility of the lithium foil itself, the lithium foil itself has viscosity and cannot be spread and cannot be assembled to produce a lithium metal negative electrode.
  • the lithium metal anode of this application uses lithium paste, which has the feasibility of ultra-thin processing, and the thickness of the lithium paste layer can reach 5 ⁇ m.
  • the prepared lithium metal battery can still improve stable current output, and obtain more battery cells, stacking times or winding times per unit mass or unit volume.
  • the use of the lithium metal negative electrode of the application can produce high-quality energy Lithium metal battery with high density and high volume energy density.

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Abstract

一种锂金属负极及其制备方法和使用该负极的锂电池，锂金属负极制备方法如下：选择锂盐和有机溶剂混合配置电解液，将电解液和增稠剂按比例混合均匀得到粘稠液体A，再按比例向粘稠液体A中加入体积当量直径为1-30μm的锂粉，搅拌混合均匀，得到膏状的锂膏，将锂膏均匀涂覆于集流体上，即可得到锂金属负极。

Description

一种锂金属负极及其制备方法和使用该负极的锂电池 技术领域
本发明涉及锂电池，特别涉及一种锂金属负极及其制备方法和使用该负极的锂电池。
背景技术
自Sony公司研发使用石墨负极以插层反应为机理的商用锂离子电池以后，锂离子电池快速发展。但是商用化的以石墨作为负极的锂离子电池难以满足对长续航以的要求，锂离子电池发展至今，具有十倍于传统石墨负极的理论容量和更低的最低负电势的锂金属负极成为了当下锂金属电池热门的研究方向。
现有市场上成功得以实际应用的锂金属电池，其能量密度和电流密度均较小，巴黎汽车共享服务“Autolib”使用了近4000辆Bluecar，这是世界上首次用于EV(Electric Vehicle，电动汽车)的商业化锂金属电池，其能量密度只有170wh/kg，并且为了提高工作电流，锂金属电池的工作温度需高达80℃。而限制高能量、高功率密度的锂金属电池推广的原因包括：由于现有的锂金属负极的表面锂沉积位点有限，局部电流较大，锂金属电池在充放电过程中，尤其是大电流充电时，锂金属负极的表面锂不均匀沉积，易产生锂枝晶，锂枝晶还会刺穿隔膜，引发电池的失效或安全问题，而且部分枝晶会脱离而形成无法再被利用的“死锂”，导致库伦效果降低。
现有的技术中抑制锂金属负极上锂枝晶的生长，主要关注形成更稳定的锂金属/电解质界面或用物理阻挡层压制枝晶生长，然而上述方法仅仅在低面容量密度下(0.5-1.0mAh/cm 2)以及低电流密度(＜0.5mA/cm 2)下可以起到有效作用，面对高能量、高功率密度电池的制备和研究时，效果有限。
同时，常规的锂金属箔片负极在放电过程中提供的电子/离子反应面积有限，不能承受更大的电流放电，限制了锂金属电池的能量功率上限和能量密度；常规的锂金属箔片负极在锂金属电池充放电循环过程中伴随极大的膨胀收缩，不利于锂金属箔片负极具有较高的循环稳定性以及在固态电池等的应用；常规的锂金属箔片负极由于高活性以及延展性，超薄处理加工不方便；再者，常规的锂金属负极对电解液无任何吸收作用，电解液在长期贮存过程中，被正极过分吸收，导致电解液在电池中分布不均匀，不利于电池的贮存以及高温性能。上述等问题造成了当下高能量、高功率密度的锂金属电池推广受到限制的现状。
发明内容
针对现有技术存在的不足，本发明的第一个目的在于提供一种锂金属负极，极大提高 了锂金属负极的面容量和电子/离子反应面积，进而提高锂金属电池的高能量性能，满足了锂金属电池高能量、高功率密度的需求。
本发明的上述技术目的是通过以下技术方案得以实现的：
一种锂金属负极，包括集流体和覆盖于集流体一侧的锂膏层，所述集流体为惰性导电材料，所述锂膏层由膏状的锂膏涂覆得到，所述锂膏包括以下质量份数的原料混合而成：
锂粉10-60份，
增稠剂10-20份，
电解液30-80份，
所述锂粉的体积当量直径为l-30μm，
所述电解液为锂盐和有机溶剂混合配制得到，所述电解液中锂盐浓度为0.5mol/L-5mol/L，所述有机溶剂均不与锂粉、锂盐反应。
通过采用上述技术方案，高比表面积的锂粉颗粒、增稠剂及电解液混合得到的锂膏，均匀覆盖于集流体材表面形成锂膏层，锂膏层中锂粉颗粒作为负极放电时的失电子材料，锂粉颗粒被增稠剂和电解液包裹而均匀分散在锂膏中，且锂粉颗粒分散密度大，由此极大提高了锂金属负极的面容量和电子/离子反应面积，进而提高锂金属电池的高能量性能，满足了锂金属电池的高能量、高功率密度需求；
同时锂粉颗粒与锂粉颗粒相互之间并非固定，锂粉颗粒在锂金属电池充放电过程中根据锂粉颗粒分布情况和锂粉颗粒大小，而在锂膏层内对锂粉颗粒表锂层积、消融以及锂金属负极的局部电流分布而适应性移动，改变分布情况，继而提高使用本申请锂金属负极的锂金属电池在充电时的锂沉积位点，并降低锂金属负极的局部电流密度，从而降低锂枝晶的生长速率，由此减缓本申请锂金属负极长期使用后库伦效率的降低，以及提高使用本申请锂金属负极的锂金属电池的循环效率以及安全性能；
锂金属电池充放电的循环过程中，现有锂金属负极因锂金属沉积/析出会出现膨胀收缩，对锂金属负极的循环稳定性造成破坏，同时对锂金属固态电池而言，锂金属负极的膨胀收缩还会破坏锂金属负极和固态电解质之间的结合，降低锂金属固态电池的循环效率。本申请中锂膏层由锂膏覆盖集流体得到，而锂膏中包括有增稠剂、液态的电解液和非固定的锂粉颗粒组成，使得锂膏层具有变形能力和良好的流动性。锂膏层可在锂金属电池充放电的循环过程发生变形进行缓冲，减缓膨胀收缩，提高锂金属负极的循环稳定性，并且在锂金属固态电池中应用时，锂膏层与固态电解质可保持良好接触，以提高本申请的锂金属负极在锂金属固态电池中的应用效果和有利于锂金属固态电池推广使用。
同时较现有锂金属负极中锂箔有限的延展性和高活性而言，锂膏层具备的流动性，使本申请的锂金属负极避免了现有锂箔负极超薄加工时锂箔厚度薄后平整性下降、变黏难以组装使用的问题，锂膏层厚度薄且可控，提高生产效率，降低生产成本，并且提高使用本申请锂金属负极的锂金属电池的质量能量密度和体积能量密度；
另外，锂膏中锂粉颗粒和增稠剂对电解液具有一定保液能力，在贮存过程中可保证电解液对锂金属的浸润以及接触，防止电解液在长期贮存过程中被锂金属电池的正极过分吸收，促进电解液在电池中的分布均匀，提高锂金属电池贮存性能。
本发明进一步设置为：所述锂盐为LiN(SO 2CF3) 2、LiNO 3，LiAsF 6，LiPF 6，LiI，LiBF 4，LiClO 4、LiSO 2CF 3、LiB(C 2O 4) 2中的一种或多种。
本发明进一步设置为：所述有机溶剂为碳酸丙烯酯、碳酸乙烯酯、氟代碳酸乙烯酯、碳酸二乙酯、碳酸二甲酯、碳酸甲乙酯、1，3-二氧戊环、碳酸二甲酯、二甲基亚砜、四氢呋喃中的一种或多种。
通过采用上述技术方案，有机溶剂作为锂盐溶解分散的载体，同时还作为锂膏的成膜助剂，提高了锂膏的成膜性，便于锂膏层超薄加工，使得使用本负极的锂金属电池，在单位质量或单位体积下得到更多的电池单元数量、叠合次或收卷次，以提高使用本申请锂金属负极的锂金属电池的质量能量密度和体积能量密度；并且其中氟代碳酸乙烯酯的添加还可抑制电解液的分解，降低界面阻抗，提高锂金属电池的能量功率。
本发明进一步设置为：所述增稠剂包含气相二氧化硅、有机膨润土、聚乙烯蜡、聚酰胺蜡或氢化蓖麻油中的一种或多种。
通过采用上述技术方案，上述增稠剂可提高电解液的稠度，防止锂粉颗粒沉降，避免锂膏析液分层，并且上述增稠剂的加入还对锂粉颗粒的表面进行原位修饰，提高锂粉颗粒与有机溶剂的相容性，促进锂粉颗粒均匀分散在锂膏内。
本发明进一步设置为：所述锂膏层厚度为5-60μm。
通过采用上述技术方案，锂膏层加工厚度薄，可降低生产成本，有利于提高使用本申请锂金属负极的锂金属电池的质量能量密度和体积能量密度。
针对现有技术存在的不足，本发明的第二个目的在于提供一种锂金属负极的制备方法，保证锂粉在锂膏内混合均匀，防止锂膏析液分层。
本发明的上述技术目的是通过以下技术方案得以实现的：
一种锂金属负极的制备方法，包括以下步骤：
S1：选择锂盐和有机溶剂，混合得到锂盐浓度为0.5mol/L-5mol/L的电解液；
S2：按质量份数将增稠剂10-20份和电解液30-80份混合均匀得到粘稠液体A；
S3：按质量份数将10-60份的锂粉加入S2所得的粘稠液体A中，搅拌混合均匀，得到膏状的锂膏；
S4：将锂膏均匀覆盖于集流体侧面形成锂膏层，得到锂金属负极。
通过采用上述技术方案，锂金属负极的制备方法中锂膏制备过程分两步进行，先将电解液与增稠剂混合得到粘稠液体A，再由粘稠液体A与锂粉混合，锂粉加入粘稠液体A后搅拌过程中，锂粉颗粒受粘稠液体A包裹保护，对锂粉颗粒之间或锂粉颗粒与搅拌设备之间碰撞起到缓冲作用，降低锂粉颗粒在搅拌过程中的破裂几率，保持锂粉颗粒完整性，并且粘性较大的粘稠液体A避免了锂粉颗粒在混合时发生沉降，使锂粉在锂膏内混合均匀，防止锂膏析液分层。
本发明进一步设置为：所述S4搅拌过程在真空压力为10-10 -4Pa的真空环境下进行。
通过采用上述技术方案，锂粉加入粘稠液体A后搅拌使，粘稠液体A中易搅入和溶入气体，真空环境下使得粘稠液体A中夹杂的微小气泡和溶有的气体脱除，避免制得的锂膏中混有微小气泡和避免锂膏层内充放电过程中析出微小气泡，由此提高锂膏的成膜性和提高本申请锂金属负极、使用本申请锂金属负极的锂金属电池的性能。
本发明进一步设置为：S1-S5步骤均在干燥气氛下完成，所述干燥气氛中水露点小于-10℃。
通过参采用上述技术方案，在锂膏制备过程中防止锂膏受潮，避免锂膏中含水质导致降低锂金属电池的库伦效率和出现安全隐患。
针对现有技术存在的不足，本发明的第三个目的在于提供一种电池，充放电循环性好，其充放电循环性好且具有高能量、高功率密度的特性。
本发明的上述技术目的是通过以下技术方案得以实现的：
一种锂金属电池，所述锂电池为液态或固态锂金属电池，其包括上述的锂金属负极。
综上所述，本发明具有以下有益效果：
1.高比表面积的锂粉颗粒、增稠剂及电解液混合得到锂膏，均匀涂覆于集流体材表面形成锂膏层，锂膏层中锂粉颗粒作为负极放电时的失电子材料，锂粉颗粒被增稠剂和电解液包裹而均匀分散在锂膏中且分散密度大，由此极大提高了锂金属负极的面容量和电子/离子反应面积，进而提高锂金属电池的高能量性能，满足了锂金属电池的高能量、高功率密度需求；
2.锂粉颗粒与锂粉颗粒相互之间并非固定，锂粉颗粒可根据锂膏层内的锂粉颗粒分布和锂粉颗粒的大小而在锂膏层内移动，继而提高锂金属电池充电时锂金属负极的锂沉积位点，并降 低锂金属负极的局部电流密度，从而降低锂枝晶的生长速率，由此减缓本申请锂金属负极长期使用后库伦效率的降低，以及提高使用本申请锂金属负极的锂金属电池的循环效率以及安全性能；
3.锂膏层具有变形能力，可在锂金属电池充放电的循环过程发生变形进行缓冲，提高锂金属负极的循环稳定性，并且在锂金属固态电池中应用时，锂膏层与固态电解质可保持良好接触，以提高本申请的锂金属负极在锂金属固态电池中的应用效果和有利于锂金属固态电池推广使用；
4.锂膏具有良好的流动性，提高了锂膏的加工性，其涂覆得到锂膏层厚度薄且可控，提高生产效率，降低生产成本，并且提高使用本申请锂金属负极的锂金属电池的质量能量密度和体积能量密度；
5.锂膏中锂粉颗粒本身和增稠剂对电解液具有一定保液能力，在贮存过程中可保证电解液对锂金属的浸润以及接触，防止电解液在长期贮存过程中被锂金属电池的正极过分吸收，促进电解液在电池中的分布均匀，提高锂金属电池贮存性能；
6.锂金属负极制备方法中锂膏获取方式分两步进行，先将电解液与增稠剂混合得到粘稠液体A，再有粘稠液体A与锂粉混合，降低锂粉颗粒在搅拌过程中的破裂几率，保证锂粉在锂膏内混合均匀，防止锂膏析液分层；
7.使用本申请的锂金属负极，使锂金属电池具有良好的循环稳定性以及高能量密度和高功率密度。
具体实施方式
实施例一，
一种锂金属负极，包括集流体和覆盖于集流体上的锂膏层。
集流体为惰性导电材料，可根据实际情况而定，此处优选为铜箔，厚度为8μm。
锂膏层由膏状的锂膏涂覆直接得到，锂膏层的厚度为5-60μm。
锂膏包括以下质量份数的原料混合而成：
锂粉10-60份，增稠剂10-20份，电解液30-80份。
锂粉的形貌为颗粒状、片状或针状，其体积当量直径为1-30μm，即锂粉颗粒最大体积当量直径为30μm。
增稠剂为气相二氧化硅、有机膨润土、聚乙烯蜡、聚酰胺蜡或氢化蓖麻油中一种或多种。
电解液通过锂盐和有机溶剂混合配制得到，其中锂盐浓度为0.5mol/L-5mol/L。锂盐为 LiN(SO 2CF 3) 2(简称LiTFSI)、LiNO 3，LiAsF 6，LiPF 6，LiI，LiBF 4，LiClO 4、LiSO 2CF 3、LiB(C 2O 4) 2(简称LiBOB)中的一种或多种，有机溶剂为碳酸丙烯酯(简称PC)、碳酸乙烯酯(简称EC)、氟代碳酸乙烯酯(简称FEC)、碳酸二乙酯(简称DEC)、碳酸二甲酯(简称DMC)、碳酸甲乙酯(简称EMC)、1，3-二氧戊环(简称DOL)、乙二醇二甲醚(简称DME)、二甲基亚砜(简称DMSO)、四氢呋喃(简称THF)中一种或多种配制而成。
上述锂金属负极的制备方法，如下：
S1：选择为LiTFSI、LiNO 3，LiAsF 6，LiPF 6，LiI，LiBF 4，LiClO 4、LiSO 2CF 3、LiBOB中的一种或多种作为锂盐，选择PC、EC、FEC、DEC、DMC、EMC、DOL、DME、DMSO、THF中一种或多种配制呈有机溶剂，将锂盐和有机溶剂混合配制得到锂盐浓度为0.5mol/L-5mol/L的电解液；
S2：按质量份数将增稠剂10-20份和电解液30-80份混合均匀，得到粘稠液体A；
S3：在真空压力为10-10 -4Pa的真空环境下，将10-60份的锂粉加入粘稠液体A中，搅拌混合均匀，得到膏状的锂膏；
S4：将锂膏均匀涂覆于集流体上，即可得到锂金属负极。
上述S1-S4步骤均在干燥气氛下完成。
根据上述制备方法，获得实施例1A-1F的锂金属负极。具体参数如表一所示。
表一.实施例1A-1F锂金属负极参数表。
Figure PCTCN2019092437-appb-000001
Figure PCTCN2019092437-appb-000002
实施例二，
一种锂金属负极，制备方法步骤与实施例一相同，获得实施例1A-1F的锂金属负极，其具体参数如表二所示。
表二.实施例2A-2F的锂金属负极参数表。
Figure PCTCN2019092437-appb-000003
实施例三，
一种锂金属电池，其为液态的锂金属电池，包括实施例一的锂金属负极。该锂金属电池的制 备方法如下：
X1：向实施例一所得的锂金属负极带有锂膏层的一侧，依次叠压组合PE-PP-PE隔膜纸和正极，得到电池芯；
X2：组装其他部件以及外壳，得到锂金属电池。
由此根据实施例1A-1F中不同的参数下制得的锂金属负极，获得不同的锂金属电池。实施例3A-3F的具体参数如表三所示。
表三.实施例3A-3F的锂金属电池参数表
Figure PCTCN2019092437-appb-000004
实施例四，
一种锂金属电池，其为液态的锂金属电池，其包括实施例二的锂金属负极。该锂金属电池的制备方法如下：
X1：向实施例一所得的锂金属负极带有锂膏层的一侧依次贴附叠合固态电解质膜和正极，得到电池芯；
X2：组装其他部件以及外壳，得到锂金属电池。
固态电解质为现有技术，且此处将固体电解质通过压制烧结或定型等方法制成薄膜，此处为LLZO固态电解质膜。
由此根据实施例2A-2F中不同的参数下制得的锂金属负极，获得不同的锂金属电池。实施例4A-4F的具体参数如表四所示。
表四.实施例4A-4F的锂金属电池参数表
Figure PCTCN2019092437-appb-000005
同时设置对比例一和对比例二。
对比例一，
一种锂金属电池，为现有液态锂金属电池。集流体为厚度为8μm的铜箔，负极为厚度为100μm的锂箔，以LiTFSI/EC-DMC作为电解液，经组合PE-PP-PE隔膜纸和NCM正极，继续进行后续组装，得到对比例一的锂金属电池。
对比例二，
一种锂金属电池，其制备方法如下：
将厚度为100μm的锂箔作为负极，其两侧分别与LLZO固态电解质膜和厚度为8μm的铜箔相贴附，再在组合NCM正极后，继续后续组装，得到对比例二的锂金属负极电池。
将实施例三、实施例四、对比例一和对比例二所得的电池使用电池检测仪(深圳市新威尔电子有限公司的市售产品)进行检测，检测结果如表五所示。
表五.实施例三、实施例四、对比例一和对比例二所得的电池性能检测结果表
Figure PCTCN2019092437-appb-000006
对比实施例三和对比例一的测试结果可知，本申请的锂金属负极制备得到的液态的锂金属电池，较现有使用锂箔作为负极的液态的锂金属电池而言，调节锂膏层厚度可根据设计需求对锂金属电池的能量密度做出调整，得到高能量密度的锂金属电池；同时实施例一制备的的锂金属电池较现有使用锂箔作为负极的液态的锂金属电池而言，其库伦效率、能量功率和循环稳定性呈现出显著的提升。
对比实施例四和对比例二的测试结果可知，本申请的锂金属负极制备得到的固态的锂金属电池，较现有使用锂箔作为负极的固态的锂金属电池而言，由于固态的锂电池中使用固体电解质膜，本申请的锂金属负极对制得锂金属电池能量密度的提升效果体现的更为明显，且对现有使用锂箔作为负极的固态的锂金属电池而言，本申请的锂金属负极对制得锂金属电 池库伦效率、能量功率和循环稳定性同样呈现出显著的提升。
实施例五，
一种锂金属电池，基于实施例3A的基础上，其区别之处在于一种锂金属负极的制备方法中电解液、增稠剂和锂粉同步加入混合。
实施例六，
一种锂金属电池，其基于实施例3A的基础上，其区别之处在于一种锂金属负极的制备方法中S4搅拌过程在常压下进行。
对比例三，
一种锂金属电池，其基于实施例3A的基础上，其区别之处在于一种锂金属负极的制备过程在相对湿度为80％的环境下制备。
实施例七，
一种锂金属电池，其基于实施例3A的基础上，其区别之处在于增稠剂组分的不同，具体组分参数釜表六所示。
表六.实施例七参数表
  实施例8A 实施例8B 实施例8C
增稠剂 羟丙基甲基纤维素 海藻酸钠 黄原胶
对实施例五至实施例七和对比例三所得的电池使用电池检测仪(深圳市新威尔电子有限公司的市售产品)进行检测，检测结果如表七所示。
表七.实施例五、实施例六、实施例七和对比例三的电池性能检测结果表
Figure PCTCN2019092437-appb-000007
对比表四中实施例3A数据和表七中实施例五数据，实施例3A的电池能量密度、平均库伦效率、循环寿命、最高稳定电流均优于实施例五，其是由于锂膏制备时先将电解液与增稠剂混合得到粘稠液体A，再有粘稠液体A与锂粉混合，避免锂粉颗粒在混合时沉降团聚，降低锂粉在混合过程中因搅拌导致的形貌破坏，并保证锂粉在锂膏内混合均匀，同时电解液与增稠剂先混合，可便于锂膏稠度调整，防止锂膏析液分层，提高锂膏品质和稳定性，提高使用实施例三锂金属负极的锂金属电池循环稳定性、能量密度和能量功率的性能。
对比表四中实施例3A数据和表七中实施例六数据，实施例3A的电池能量密度、平均库伦效率、循环寿命均优于实施例六，锂金属负极生产时在真空环境下操作，减少锂膏内混杂的微小气泡和溶解的气体量，可提高提高使用本申请锂金属负极的锂金属电池循环稳定性、能量密度和能量功率的性能。
对比例三中，潮湿环境下制备的锂金属负极，组装成电池后，电池无法使用，由此在干燥气氛下，进行锂膏的制备，可避免锂膏受潮，提高本申请锂金属电池的制造成品率，减少生产产品，以及防止出现安全隐患。
对比表四中实施例3A数据和表七中实施例七数据，实施例3A的电池能量密度、平均库伦效率、循环寿命均优于实施例七，本申请中增稠剂选用气相二氧化硅、有机膨润土、聚乙烯蜡、聚酰胺蜡或氢化蓖麻油中的一种或多种，除提高电解液稠度，防止锂颗粒沉降，锂膏析液分层的同时，还可以对锂粉颗粒的表面进行原位修饰，促进锂粉颗粒均匀分散在锂膏内，提高电池性能。
对比例四，
一种锂金属电池，基于对比例二的基础上，其区别之处在于制备过程中作为负极的锂箔厚度不同。
根据上述制备方法使用不同厚度锂箔制备锂金属电池，得到对比例4A-4E，其锂箔厚度与锂负极成品率如表八所示。
表八.对比例四的锂金属电池生产参数及其锂金属负极生产产品率表。
Figure PCTCN2019092437-appb-000008
当锂箔厚度小于100μm后，获得锂箔的厚度偏差增大，组装过程中难以组合，且因锂箔自身的活性和延展性，锂箔自身产生粘性，无法铺展而无法组装生产锂金属负极。
由表一和表二中锂膏层厚度，以及表五中各锂金属电池的测试结果可知，本申请的锂金属负极使用锂膏，具有超薄加工的可行性，锂膏层厚度可达到5μm且制得的锂金属电池依旧可提高稳定的电流输出，在单位质量或单位体积下得到更多的电池单元数量、叠合次或收卷次，使用本申请锂金属负极可生产具有高质量能量密度和高体积能量密度特性的锂金属电池。
本具体实施例仅仅是对本发明的解释，其并不是对本发明的限制，本领域技术人员在阅读完本说明书后可以根据需要对本实施例做出没有创造性贡献的修改，但只要在本发明的 权利要求范围内都受到专利法的保护。

Claims (9)

  1. 一种锂金属负极，其特征在于，包括集流体和覆盖于集流体一侧的锂膏层，所述集流体为惰性导电材料，所述锂膏层由膏状的锂膏涂覆得到，所述锂膏包括以下质量份数的原料混合而成：
    锂粉 10-60份，
    增稠剂 10-20份，
    电解液 30-80份，
    所述锂粉的体积当量直径为1-30μm，
    所述电解液为锂盐和有机溶剂混合配制得到，所述电解液中锂盐浓度为0.5mol/L-5mol/L，
    所述有机溶剂均不与锂粉、锂盐反应。
  2. 根据权利要求1所述的一种锂金属负极，其特征在于，所述锂盐为LiN(SO 2CF 3) 2、LiNO 3，LiAsF 6，LiPF 6，LiI，LiBF 4，LiClO 4、LiSO 2CF 3、LiB(C 2O 4) 2中的一种或多种。
  3. 根据权利要求2所述的一种锂金属负极，其特征在于，所述有机溶剂为碳酸丙烯酯、碳酸乙烯酯、氟代碳酸乙烯酯、碳酸二乙酯、碳酸二甲酯、碳酸甲乙酯、1，3-二氧戊环、乙二醇二甲醚、二甲基亚砜、四氢呋喃中的一种或多种。
  4. 根据权利要求3所述的一种锂金属负极，其特征在于，所述增稠剂包含气相二氧化硅、有机膨润土、聚乙烯蜡、聚酰胺蜡、氢化蓖麻油中的一种或多种。
  5. 根据权利要求1所述的一种锂金属负极，其特征在于，所述锂膏层厚度为5-60μm。
  6. 根据权利要求1-5任意一项所述的一种锂金属负极的制备方法，其特征在于，包括以下步骤：
    S1：选择锂盐和有机溶剂，混合得到锂盐浓度为0.5mol/L-5mol/L的电解液；
    S2：按质量份数将增稠剂10-20份和电解液30-80份混合均匀得到粘稠液体A；
    S3：按质量份数将10-60份的锂粉加入S2所得的粘稠液体A中，搅拌混合均匀，得到膏状的锂膏；
    S4：将锂膏均匀覆盖于集流体侧面形成锂膏层，得到锂金属负极。
  7. 根据权利要求6所述的一种锂金属负极的制备方法，其特征在于，所述S4搅拌过程在真空压力为10-10 -4Pa的真空环境下进行。
  8. 根据权利要求7所述的一种锂金属负极的制备方法，其特征在于，S1-S5步骤均在干燥气氛下完成，所述干燥气氛中水露点小于-10℃。
  9. 一种锂电池，其特征在于，所述锂电池为液态或固态锂金属电池，其包括权利要求1-5任意一项所述的锂金属负极。
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