WO2017193778A1 - 锂金属电极及其制备方法、锂金属二次电极负极、电池 - Google Patents

锂金属电极及其制备方法、锂金属二次电极负极、电池 Download PDF

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WO2017193778A1
WO2017193778A1 PCT/CN2017/081106 CN2017081106W WO2017193778A1 WO 2017193778 A1 WO2017193778 A1 WO 2017193778A1 CN 2017081106 W CN2017081106 W CN 2017081106W WO 2017193778 A1 WO2017193778 A1 WO 2017193778A1
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lithium
foam
lithium metal
metal
electrode
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English (en)
French (fr)
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王平华
李慧
夏圣安
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Huawei Technologies Co Ltd
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Huawei Technologies Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H01M4/04—Processes of manufacture in general
    • 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
    • H01M12/00—Hybrid cells; Manufacture thereof
    • H01M12/08—Hybrid cells; Manufacture thereof composed of a half-cell of a fuel-cell type and a half-cell of the secondary-cell type
    • 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
    • H01M4/64—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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/663—Selection of materials containing carbon or carbonaceous materials as conductive part, e.g. graphite, carbon fibres
    • 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
    • H01M4/70—Carriers or collectors characterised by shape or form
    • H01M4/80—Porous plates, e.g. sintered carriers
    • H01M4/808—Foamed, spongy materials
    • 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 the technical field of lithium batteries, in particular to a lithium metal electrode and a preparation method thereof, a lithium metal secondary electrode negative electrode and a battery.
  • a lithium metal secondary battery is a rechargeable lithium battery in which a lithium metal electrode is used as a negative electrode.
  • Lithium metal secondary batteries mainly include lithium metal air batteries and lithium sulfur batteries, depending on the material of the positive electrode.
  • lithium metal Since lithium metal has a very high theoretical specific capacity (3860 mAh/g), a most negative reduction potential (-3.04 V, relative to a hydrogen standard potential), and a very small density (0.59 g/cm 3 ), lithium metal is secondary The energy density of the battery is much greater than other battery systems (for example, the theoretical energy density of a lithium metal air battery can reach 11140 Wh/kg, and the theoretical energy density of a lithium sulfur battery can reach 2680 Wh/kg).
  • the lithium metal electrode currently used for a lithium metal secondary battery mainly uses a sheet metal lithium or a form in which metal lithium particles are coated on a sheet electrode substrate.
  • the inventors have found that at least the following problems exist in the prior art: the existing lithium metal electrode for a lithium metal secondary battery may undergo volume expansion during charge and discharge, affecting the lithium metal secondary battery. Stability and cycle performance; at the same time, during long-term charge and discharge, lithium will deposit on the surface of the negative electrode to form lithium dendrites. When the lithium dendrite grows to penetrate the separator of the lithium metal secondary battery, it will cause a short circuit and cause an explosion. .
  • embodiments of the present invention provide a lithium metal electrode having a small volume change and a small amount of dendrite generation during charge and discharge, a preparation method thereof, a lithium metal secondary electrode negative electrode, and a battery.
  • a lithium metal electrode comprising: a foam electrode substrate having a plurality of cell cavities; and metal lithium particles distributed in at least one cell cavity of the foam electrode substrate; the foam electrode substrate
  • the material is a foam metal material or a carbon foam material.
  • the electrode substrate is a foam electrode substrate having a plurality of pore cavity structures, and the metal lithium particles are distributed in at least one pore cavity of the foam electrode substrate.
  • the pore cavity of the foam electrode substrate can effectively limit the volume expansion of the metal lithium particles during charge and discharge, thereby effectively improving the stability and cycle performance of the lithium metal secondary battery using the lithium metal electrode as a negative electrode.
  • the pore cavity of the foam electrode substrate can effectively increase the surface area of the lithium metal electrode, which not only greatly improves the high current fast charging capability of the lithium metal secondary battery using the lithium metal electrode as the negative electrode, but also effectively reduces lithium.
  • the formation of dendrites avoids battery short-circuit problems caused by lithium dendrites piercing the diaphragm, improving Safety performance of lithium metal secondary batteries.
  • the metal lithium particles may be distributed in more than 20% of the plurality of pore cavities.
  • Metal lithium particles may be distributed in the plurality of pore cavities of 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more.
  • the metal lithium particles are also distributed in regions other than the plurality of cell cavities on the foam electrode substrate due to limitations in the preparation process conditions.
  • the number of the metallic lithium particles distributed in the pore cavity of the foam electrode substrate is greater than the number of the metallic lithium particles distributed in a region other than the plurality of pore cavities; or
  • the density of the metallic lithium particles in the pore cavity of the foam electrode substrate is greater than the density of the metallic lithium particles distributed in a region other than the plurality of pore cavities.
  • the present invention is ensured by controlling the relationship between the number and density of metallic lithium particles distributed in the pore cavity of the foam electrode substrate and the number and density of metallic lithium particles distributed in regions other than the plurality of pore cavities.
  • the performance of the lithium metal electrode provided by the examples.
  • the pore cavity of the foam electrode substrate may have a diameter of from 100 nanometers to 50 micrometers. If the diameter of the pore cavity of the foam electrode substrate is too small, the metallic lithium particles do not easily enter the pore cavity, thereby increasing the difficulty in preparing the lithium metal electrode of the present embodiment. If the diameter of the pore cavity of the foam electrode substrate is too large, the number of pore cavities of the foam electrode substrate may be reduced in the case where the size of the lithium metal electrode is constant, and the volume expansion of the metal lithium particles is not good. Limiting the effect, thereby affecting the performance of the lithium metal electrode.
  • the metal lithium particles are prevented from reacting with the external atmosphere
  • the lithium metal electrode further includes: a protective layer coated on the surface of the metallic lithium particles.
  • the material of the protective layer is a lithium ion good conductor material.
  • the material of the protective layer may be selected from the group consisting of Li 2 CO 3 , Li 4 SiO 4 , LiF, Li 3 PO 3 , TiO 2 , Li 2 TiO 3 , Li 4 Ti 5 O 12 , SiO 2 , SnO 2 , SiC. At least one of LiAlO 2 , Al 2 O 3 , NiS, CuS, FeS, MnS, Ag 2 S, and TiS 2 .
  • the metal foam material is selected from at least one of foamed nickel, copper foam, titanium foam, and foamed iron.
  • the carbon foam material is selected from at least one of foamed carbon, foamed carbon nanotubes, and foamed graphene.
  • the graphene used in the foam graphene is at least one selected from the group consisting of graphene oxide, reduced graphene, and element-doped graphene.
  • the graphene oxide may be at least one of a covalent bond functionalized graphene and a non-covalently bonded functional graphene.
  • the element doped in the element doped graphene is at least one selected from the group consisting of nitrogen, sulfur, and phosphorus. It should be noted that the use of the element doped graphene is more advantageous for improving the fast charging capability of the lithium metal secondary battery using the lithium metal electrode provided by the embodiment of the present invention as a negative electrode.
  • a method for preparing a lithium metal electrode comprising:
  • the material of the foam electrode substrate is a foam metal material or a carbon foam material.
  • the electrode substrate is a foam electrode substrate having a plurality of pore cavity structures, and the metal lithium particles are distributed in at least one pore cavity of the foam electrode substrate.
  • the pore cavity of the foam electrode substrate can effectively limit the volume expansion of the metal lithium particles during charge and discharge, and inhibit the growth of lithium dendrites, thereby effectively improving the lithium metal electrode prepared by the preparation method of the embodiment of the present invention as a negative electrode. Lithium metal Secondary battery stability, cycle performance, fast charging capability and safety performance.
  • more than 20% of the plurality of pore cavities may be distributed with metallic lithium particles. It is also possible that 50%, 60%, 70% or more of the plurality of pore cavities are distributed with metallic lithium particles.
  • the metallic lithium particles may be coated by vapor deposition.
  • the metal lithium particles can be uniformly applied to the pore cavity of the foam electrode substrate by vapor deposition.
  • the vapor deposition method may specifically be a vacuum evaporation method; the vacuum evaporation is performed by fixing the foam electrode substrate directly above the metal lithium particle evaporation source, under a pressure of 1 ⁇ 10 ⁇ 2 Pa or less,
  • the metal lithium particle evaporation source is bombarded with an electron beam having a current of 50 to 500 mA and a voltage of 3 to 12 kV, and the bombardment time is 5 to 50 minutes, and the foam electrode substrate and the metal lithium particle evaporation source are The distance is 30 to 150 cm.
  • the distribution of the metallic lithium particles obtained by the above vacuum evaporation conditions is more uniform, which is advantageous for improving the performance of the obtained lithium metal electrode.
  • the metal lithium particles are prevented from reacting with the external atmosphere, and the preparation method further includes: the metal lithium particles The surface is coated with a protective layer; the material of the protective layer is a lithium ion good conductor material.
  • the material of the protective layer is selected from the group consisting of Li 2 CO 3 , Li 4 SiO 4 , LiF, Li 3 PO 3 , TiO 2 , Li 2 TiO 3 , Li 4 Ti 5 O 12 , SiO 2 , SnO 2 , SiC, At least one of LiAlO 2 , Al 2 O 3 , NiS, CuS, FeS, MnS, Ag 2 S, and TiS 2 .
  • the metal foam material is selected from at least one of foamed nickel, copper foam, titanium foam, and foamed iron.
  • the carbon foam material is selected from at least one of foamed carbon, foamed carbon nanotubes, and foamed graphene.
  • the graphene used in the foam graphene is at least one selected from the group consisting of graphene oxide, reduced graphene, and element-doped graphene.
  • the graphene oxide is selected from at least one of a covalently bonded functional graphene and a non-covalently bonded functional graphene.
  • the element doped in the element doped graphene is at least one selected from the group consisting of nitrogen, sulfur, and phosphorus.
  • the protective layer may be coated on the surface of the metallic lithium particles by vapor deposition.
  • the protective layer can be uniformly applied to the surface of the metallic lithium particles by vapor deposition.
  • a lithium metal secondary battery anode comprising: at least one lithium metal electrode according to the first aspect.
  • the pore cavity of the foam electrode substrate can effectively limit the volume expansion of the metal lithium particles during charging and discharging and inhibit the formation of lithium dendrites, thereby, the lithium metal
  • the electrode can effectively improve the stability performance, cycle performance, high current fast charging capability, and safety performance of the lithium metal secondary battery.
  • the lithium metal secondary battery negative electrode when the lithium metal secondary battery negative electrode includes a plurality of the lithium metal electrodes, the lithium metal secondary battery negative electrode is used to facilitate the use of the lithium metal secondary battery negative electrode. Also included is a substrate for supporting the lithium metal electrode. A plurality of the lithium metal electrodes may be disposed on the substrate in an array.
  • a lithium metal secondary battery comprising: an outer casing, an electrolyte, a positive electrode, a negative electrode, and a separator, wherein the negative electrode is the lithium metal secondary battery negative electrode according to the third aspect.
  • the metal lithium particles are distributed in the cavity cavity of the foam electrode substrate, and the cavity cavity of the foam electrode substrate can limit the volume expansion of the lithium metal particles and inhibit lithium.
  • the growth of dendrites, therefore, the lithium metal secondary battery using the lithium metal secondary battery negative electrode as a negative electrode has good stability, cycle performance, high current fast charging capability, and safety performance.
  • the lithium metal secondary battery is a lithium metal air battery or a lithium sulfur battery.
  • FIG. 1 is a schematic structural view of a lithium metal electrode provided in Embodiment 1;
  • FIG. 2 is a schematic structural view of another lithium metal electrode provided in Embodiment 1;
  • FIG. 3 is a schematic view showing a cross section of a foam electrode substrate in a lithium metal electrode according to Embodiment 1;
  • Figure 3-1 is a schematic view of a rectangular cross section
  • Figure 3-2 is a schematic view of a square cross section
  • Figure 3-3 is a schematic view of a circular cross section
  • Figure 3-4 is a schematic view of a cross section of a C-shape
  • FIG. 5 is a schematic flow chart of a method for preparing a lithium metal electrode according to Embodiment 2;
  • FIG. 6 is a scanning electron micrograph of a method for preparing a lithium metal electrode according to Embodiment 2;
  • FIG. 7 is a schematic diagram of a method for preparing a foam-reduced graphene in the second embodiment
  • FIG. 8 is a schematic structural view of a lithium metal secondary battery negative electrode provided in Embodiment 3.
  • FIG. 9 is a schematic structural view of another lithium metal secondary battery negative electrode provided in the third embodiment.
  • reference numeral 100 in the drawing denotes a lithium metal electrode
  • 1 denotes a foam electrode substrate
  • 11 denotes a pore cavity
  • 2 denotes metallic lithium particles
  • 300 denotes a lithium metal secondary battery negative electrode
  • 3 denotes a substrate.
  • the present embodiment provides a lithium metal electrode 100 comprising: a foam electrode substrate 1 having a plurality of cell cavities 11, and at least one cell cavity 11 distributed in the foam electrode substrate 1.
  • the material of the foam electrode substrate 1 is a foam metal material or a carbon foam material.
  • the metal foam material and the carbon foam material are three-dimensional materials having a plurality of pore cavity structures.
  • the metal metal particles 2 are distributed in the at least one cell cavity 11 of the foam electrode substrate 1 by using a metal foam material or a carbon foam material as an electrode substrate of the lithium metal electrode, and the cell cavity 11 of the foam electrode substrate 1
  • the volume expansion of the metallic lithium particles 2 during charge and discharge can be effectively limited, thereby effectively improving the stability and cycle performance of the lithium metal secondary battery using the lithium metal electrode 100 as a negative electrode.
  • the cavity cavity 11 of the foam electrode substrate 1 can effectively increase the surface area of the lithium metal electrode 100, which not only greatly improves the high current fast charging capability of the lithium metal secondary battery using the lithium metal electrode as a negative electrode, but also effectively The formation of lithium dendrites is reduced, the short circuit of the battery due to the penetration of the lithium dendrites into the separator is avoided, and the safety performance of the lithium metal secondary battery is improved.
  • the percentage of the channel cavity in which the metal lithium particles are distributed should be controlled.
  • more than 20% of the channel cavity 11 is distributed with metallic lithium particles.
  • 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 55% or more, 60% or more, 65% or more, More than 70%, more than 75%, more than 80%, more than 85%, more than 90%, more than 95%, and 100% of the pores are distributed with metallic lithium particles.
  • metal lithium particles 2 are all distributed in the cell cavity 11 of the foam electrode substrate 1, as shown in FIG. 2, a plurality of holes on the foam electrode substrate 1 are empty. Metal lithium particles 2 may also be distributed in a region other than the cavity 11, such as the surface of the foam electrode substrate.
  • the region other than the cell cavity 11 is not capable of restricting the volume expansion of the metallic lithium particles 2, nor inhibiting the formation of lithium dendrites, and therefore, in order to secure the performance of the lithium metal electrode 100 of the present embodiment, on the foam electrode substrate 1
  • metal lithium particles 2 are also distributed in a region other than the plurality of cell cavities 11, optionally, the number of metal lithium particles distributed in the cell cavity 11 of the foam electrode substrate 1 is larger than that distributed in a plurality of cell cavities
  • the number of metallic lithium particles 2 in the region other than 11 or the density of metallic lithium particles distributed in the pore cavity of the foam electrode substrate is larger than the density of metallic lithium particles distributed in regions other than the plurality of pore cavities.
  • the number of metallic lithium particles 2 distributed in the pore cavity 11 of the foam electrode substrate 1 is larger than the number of metallic lithium particles 2 distributed in a region other than the plurality of pore cavities 11, and is distributed in the foam electrode substrate.
  • the density of the metallic lithium particles 2 in the pore cavity 1 is also greater than the density of the metallic lithium particles 2 distributed in the regions other than the plurality of pore cavities 11.
  • the diameter of the cavity 11 of the foam electrode substrate 1 may be 100 nm to 50 ⁇ m, for example, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700. Nano, 800 nm, 900 nm, 1 micron, 5 micron, 10 micron, 15 micron, 20 micron, 25 micron, 30 micron, 35 micron, 40 micron, 45 micron, etc. If the diameter of the cell cavity 11 of the foam electrode substrate 1 is too small, the metal lithium particles 2 do not easily enter the cell cavity 11, thereby increasing the difficulty in preparation of the lithium metal electrode 100 of the present embodiment.
  • the number of the cell cavities 11 of the foam electrode substrate 1 may be reduced in the case where the size of the lithium metal electrode 100 is constant, and the volume expansion of the metal lithium particles 2 cannot be performed. To a very good limiting effect, thus affecting the performance of lithium metal electrodes.
  • the metal lithium particles 2 may be nano metal lithium particles having a diameter of 100 nm or less, for example, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 in diameter.
  • the use of nano metallic lithium particles can increase the capacity, rapid charging performance, and cycle performance in a high temperature environment of a lithium metal secondary battery.
  • the shape of the cross section of the foam electrode substrate 1 is not strictly limited, and any conventional means in the art, such as a rectangle (as shown in FIG. 3-1), a square (such as Figure 3-2 shows a circle, as shown in Figure 3-3, and a C-shape (as shown in Figure 3-4).
  • the metal lithium particles 2 are prevented from reacting with the external atmosphere, and the surface of the metallic lithium particles 2 may be coated with a protective layer ( Not shown in the figure).
  • the material of the protective layer is a good lithium ion conductor material, and the lithium ion good conductor material has a good lithium ion conduction effect, and the metal lithium particle is prevented from reacting with the external atmosphere while ensuring the reactivity of the metal lithium particle, thereby ensuring
  • the lithium metal electrode 100 provided in this embodiment functions as a lithium metal secondary battery of a negative electrode.
  • the material of the protective layer may be Li 2 CO 3 , Li 4 SiO 4 , LiF, Li 3 PO 3 , TiO 2 , Li 2 TiO 3 , Li 4 Ti 5 O 12 , SiO 2 , SnO 2 , SiC, LiAlO 2 . At least one of Al 2 O 3 , NiS, CuS, FeS, MnS, Ag 2 S, and TiS 2 .
  • the material of the foam electrode substrate 1 may be selected from materials that are not intercalated with lithium.
  • the metal foam material may be foamed nickel, copper foam, titanium foam or foamed iron, and a metal foam material may be used alone or in combination with a plurality of foam metal materials.
  • the carbon foam material can be foamed carbon, Foamed carbon nanotubes or foamed graphene can be used alone or in combination with a variety of carbon foam materials.
  • foamed graphene is a three-dimensional material having a skeleton structure and a pore cavity structure formed by stacking graphene sheets. Compared with other metal foam materials and carbon foam materials, foamed graphene has higher strength and superior electrical properties. Therefore, in the present embodiment, the foam electrode substrate is preferably made of foamed graphene.
  • the distribution of metallic lithium particles 2 in the pore cavity 11 of the foamed graphene is shown in Fig. 4, and the metallic lithium particles 2 are uniformly distributed in the pore cavity 11 of the foamed graphene.
  • the graphene used for the foamed graphene may be at least one of graphene oxide, reduced graphene, and element-doped graphene.
  • the graphene oxide may be at least one of a covalent bond functionalized graphene and a non-covalently bonded functional graphene; the element doped with the element doped graphene may be at least one of nitrogen, sulfur, and phosphorus.
  • the element doping changes the molecular structure of the graphene, the lithium metal negative electrode which is doped with elemental doped graphene as the material of the foam electrode substrate 1 has a physical and chemical double lithium storage function, and thus element-doped graphite is used.
  • the olefin is more advantageous for improving the rapid charging ability of the lithium metal secondary battery using the lithium metal electrode provided in the present embodiment as a negative electrode.
  • This embodiment provides a method for preparing a lithium metal electrode.
  • the preparation method includes the following steps:
  • step 201 a foam electrode substrate having a plurality of cell cavities is prepared.
  • Step 202 coating metal lithium particles in at least one of the cavity cavities of the foam electrode substrate; wherein the material of the foam electrode substrate is a foam metal material or a carbon foam material.
  • the electrode substrate is a foam electrode substrate having a plurality of pore cavity structures, and the metal lithium particles are distributed in at least one pore cavity of the foam electrode substrate.
  • the pore cavity of the foam electrode substrate can effectively limit the volume expansion of the metal lithium particles during charge and discharge, thereby effectively improving the stability of the lithium metal secondary battery using the lithium metal electrode prepared by the preparation method of the present embodiment as a negative electrode. Cycle performance.
  • the pore cavity of the foam electrode substrate can effectively increase the surface area of the lithium metal electrode, which not only greatly improves the high current fast charging capability of the lithium metal secondary battery using the lithium metal electrode as the negative electrode, but also effectively reduces lithium.
  • the formation of dendrites avoids the short circuit of the battery caused by the lithium dendrite piercing the separator, and improves the safety performance of the lithium metal secondary battery.
  • the coating conditions should be controlled to control the percentage of the pore cavity in which the metal lithium particles are distributed to a certain value, for example, more than 20% of the pore cavity 11 can be made.
  • metallic lithium particles distributed therein, or 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, and 75%.
  • 80% or more, 85% or more, 90% or more, 95% or more, and 100% of the pores are distributed with metal lithium particles.
  • metallic lithium particles may be applied to regions other than the plurality of cell cavities on the foam electrode substrate.
  • the region other than the pore cavity cannot restrict the volume expansion of the metallic lithium particles and the formation of lithium dendrites cannot be suppressed, in order to ensure the performance of the lithium metal electrode prepared in the present embodiment, the coating of the metallic lithium particles is completed. Thereafter, the metallic lithium particles in all or part of the region other than the plurality of pore cavities coated on the foam electrode substrate can be removed, so that the amount of metallic lithium particles coated in the pore cavity of the foam electrode substrate is larger than that of the coating.
  • the number of metallic lithium particles in a region other than the plurality of pore cavities, or the density of metallic lithium particles coated in the pore cavity of the foam electrode substrate is greater than that coated in a region other than the plurality of pore cavities Density of metallic lithium particles, or coating
  • the amount and density of metallic lithium particles overlying the pore cavity of the foam electrode substrate are greater than the metallic lithium particles coated in regions other than the plurality of pore cavities.
  • the metal lithium particles in the regions other than the plurality of cell cavities coated on the foam electrode substrate can be removed by a gas purge.
  • the coating method of the metal lithium particles is not particularly limited in this embodiment, and a method of coating metal lithium particles commonly used in the art may be, for example, a vapor deposition method.
  • the vapor deposition method may specifically be a physical vapor deposition method, and more specifically, may be a vacuum evaporation method.
  • the specific conditions of the vacuum evaporation are not particularly limited in the embodiment, and the conventional technical means in the field may be used.
  • the thickness of the metallic lithium particle coating can be controlled by controlling the time of vacuum evaporation.
  • an optional condition for coating the lithium metal particles by vacuum evaporation is: fixing the foam electrode substrate directly above the evaporation source of the metal lithium particles, below 1 ⁇ 10 ⁇ 2 Pa Under pressure, the metal lithium particle evaporation source is bombarded with an electron beam with a current of 50-500 mA and a voltage of 3-12 kV. The bombardment time is 5 to 50 minutes, and the distance between the foam electrode substrate and the metal lithium particle evaporation source is 30. ⁇ 150 cm.
  • Another optional condition for coating lithium metal particles by vacuum evaporation is that the metal lithium particles are placed in a crucible of a vacuum evaporation apparatus as an evaporation source, and the foam electrode substrate is horizontally fixed directly above the evaporation source and evaporated. Source 80 cm position. Then, vacuum treatment is performed. When the pressure drops to 1 ⁇ 10 ⁇ 3 Pa, the pressure is stabilized and the electron beam bombards the evaporation source lithium metal particles to start evaporation, wherein the electron beam voltage is 7.5 kV and the current is 70. mA, the evaporation time is 20 minutes. After the vapor deposition is completed, it is naturally cooled in a vacuum state, and the furnace is vented to complete the coating of the metallic lithium particles.
  • the distribution of the metallic lithium particles obtained by the above vacuum evaporation conditions is more uniform, which is advantageous for improving the performance of the obtained lithium metal electrode.
  • the preparation method provided in this embodiment may further include: step 203,
  • the surface of the metallic lithium particles is coated with a protective layer, wherein the material of the protective layer is a lithium ion good conductor material.
  • the lithium ion good conductor material has a good lithium ion conduction effect, and ensures the reactivity of the metal lithium particles while avoiding the contact of the metallic lithium particles with the external atmosphere, thereby ensuring the lithium metal electrode prepared by the preparation method provided by the embodiment.
  • the material of the protective layer may be Li 2 CO 3 , Li 4 SiO 4 , LiF, Li 3 PO 3 , TiO 2 , Li 2 TiO 3 , Li 4 Ti 5 O 12 , SiO 2 , SnO 2 , SiC, LiAlO 2 . At least one of Al 2 O 3 , NiS, CuS, FeS, MnS, Ag 2 S, and TiS 2 .
  • the method of applying the protective layer is not particularly limited in this embodiment, and any conventional means in the art, such as a vapor deposition method.
  • the vapor deposition method may specifically be a physical vapor deposition method, and more specifically, may be a vacuum evaporation method.
  • an optional vacuum evaporation coating is used to place the LiF particles in a crucible of a vacuum evaporation apparatus as an evaporation source to level the foam electrode substrate coated with metallic lithium particles. It is fixed directly above the evaporation source and 30 to 150 cm away from the evaporation source; then vacuum treatment is performed, and when the pressure drops below 1 ⁇ 10 -2 Pa, the electron beam bombardment of the evaporation source LiF particles is started, and evaporation is started.
  • the electron beam voltage is 3 to 12 kV
  • the current is 50 to 500 mA
  • the evaporation time is 5 to 50 minutes.
  • LiF particles are placed in a crucible of a vacuum evaporation apparatus as an evaporation source, and a metal electrode coated with a lithium metal particle is used.
  • the horizontal position was fixed directly above the evaporation source and 80 cm away from the evaporation source; then vacuum treatment was performed, and when the pressure was lowered to 1 ⁇ 10 -3 Pa, the electron beam bombardment of the evaporation source LiF particles was started, and evaporation was started.
  • the electron beam voltage was 7.5 kV
  • the current was 70 mA
  • the evaporation time was 5 minutes. After the vapor deposition is completed, it is naturally cooled in a vacuum state, and ventilated to obtain a lithium metal electrode coated with a protective layer.
  • the preparation of the foam electrode substrate having a plurality of cell cavities in step 201 specifically includes preparing a foam electrode substrate, and the requirements of the lithium metal electrode on the lithium metal electrode to the foam electrode substrate The dimensions are tailored and the steps of removing impurities from the foam electrode substrate.
  • the step of preparing the foam electrode substrate can be omitted. Wherein, removing the impurities on the foam electrode substrate can make the metal lithium particles adhere more closely to the foam electrode substrate, and the impurities on the foam electrode substrate can be removed by ion beam bombardment.
  • An optional ion beam bombardment condition is: bombarding the foam electrode substrate with an ion beam having a voltage of 150-300 volts and a current of 0.1-0.5 amps under a vacuum pressure of 0.1 to 10 Pa, and the bombardment time is 1-20. minute.
  • Another optional ion beam bombardment condition is to bombard the foam electrode substrate with an ion beam of 200 volts and a current of 0.2 amps at a vacuum pressure of 5 Pa, with a bombardment time of 5 minutes.
  • the material of the foam electrode substrate may be selected from materials that are not intercalated with lithium.
  • the metal foam material may be foamed nickel, copper foam, titanium foam or foamed iron, and a metal foam material may be used alone or in combination with a plurality of foam metal materials.
  • the carbon foam material may be foamed carbon, foamed carbon nanotubes or foamed graphene, and a carbon foam material may be used alone or in combination with a plurality of carbon foam materials.
  • the graphene used for the foamed graphene may be at least one of graphene oxide, reduced graphene, and element-doped graphene.
  • the graphene oxide may be at least one of a covalently bonded functionalized graphene and a non-covalently bonded functional graphene; the element doped with the elemental doped graphene may be at least one of nitrogen, sulfur, and phosphorus.
  • foamed metal materials such as foamed nickel, copper foam, titanium foam, and foamed iron may be directly purchased or may be prepared by depositing a metal on an organic foam material using an organic foam material such as a polyurethane foam as a template. The organic foam material is then removed by heat decomposition or dissolution of an organic solvent to obtain a foamed metal material.
  • the above foamed carbon can be produced by depositing carbon on an organic foam material such as a polyurethane foam, and then removing the organic foam material by heat decomposition or organic dissolution.
  • Foam graphene can be obtained by freeze-drying graphene, freeze-drying graphene, or depositing graphene on metal foam by using a metal foam material such as foamed nickel as a template, and then removing the metal foam material. The method is obtained.
  • the foam-reduced graphene and the foam-doped graphene can be obtained by reducing or elementally doping the foamed graphene oxide.
  • an optional method for preparing foam-reduced graphene is as foam nickel (a foam having a density of 420-440 g/cm 3 and a thickness of 1.6 mm-2.0 mm can be used).
  • Nickel a foam having a density of 420-440 g/cm 3 and a thickness of 1.6 mm-2.0 mm can be used.
  • Nickel As a template, the nickel foam is placed in a quartz vacuum high-temperature tube sintering furnace, heated to 800-1200 ° C under a protective gas atmosphere and held for 30-60 min, and then methane gas, methane gas is continuously introduced into the sintering furnace.
  • the introduction time was 8 to 12 minutes, and the above sintering furnace was rapidly cooled to room temperature at a rate of 80 to 100 ° C / min to obtain foamed nickel coated with graphene oxide.
  • the obtained nickel oxide coated with graphene oxide is immersed in a mixed solution of polymethyl methacrylate (PMMA) and ethyl lactate having a mass fraction of 3% to 5% for 5 to 10 minutes to reduce the graphene oxide, and then It is naturally dried at room temperature, and then incubated at a temperature of 150 to 200 ° C for 0.5 to 1 h to obtain a reduced graphene-coated foamed nickel coated with PMMA.
  • PMMA polymethyl methacrylate
  • ethyl lactate having a mass fraction of 3% to 5% for 5 to 10 minutes to reduce the graphene oxide
  • the reduced graphene-encapsulated foamed nickel coated with PMMA is placed in a dilute hydrochloric acid solution having a concentration of 3 to 4 mol/L, and magnetically stirred for 4 to 8 hours to completely etch nickel foam by hydrochloric acid to obtain a nickel-removed nickel.
  • Template of PMMA coated foam to reduce graphene is immersed in an acetone solution at 55-65 ° C for 1 to 2 hours to remove PMMA, and the foam-reduced graphene from which PMMA is removed is obtained, washed in deionized water, freeze-dried, The heat treatment gives a pure foam-reduced graphene.
  • foam-reduced graphene as an example, referring to FIG. 7, another optional method for preparing foam-reduced graphene is: using foamed nickel as a template, and placing the nickel foam in a quartz vacuum high-temperature tube sintering furnace in a protective gas The temperature was raised to 1000 ° C in the atmosphere and kept for 60 min, then methane gas was continuously introduced into the above sintering furnace, the methane gas was introduced for 10 min, and the sintering furnace was rapidly cooled to room temperature at a rate of 80 ° C / min to obtain oxidized.
  • Graphene coated foamed nickel is: using foamed nickel as a template, and placing the nickel foam in a quartz vacuum high-temperature tube sintering furnace in a protective gas The temperature was raised to 1000 ° C in the atmosphere and kept for 60 min, then methane gas was continuously introduced into the above sintering furnace, the methane gas was introduced for 10 min, and the sintering furnace was rapidly cooled to room
  • the obtained nickel oxide coated with graphene oxide is immersed in a mixed solution of polymethyl methacrylate (PMMA) and ethyl lactate having a mass fraction of 3% to 5% for 10 minutes to reduce graphene oxide and then at room temperature. It is naturally dried and then kept at a temperature of 200 ° C for 1 h to obtain a reduced graphene-encapsulated foamed nickel coated with PMMA.
  • PMMA polymethyl methacrylate
  • ethyl lactate having a mass fraction of 3% to 5% for 10 minutes to reduce graphene oxide and then at room temperature. It is naturally dried and then kept at a temperature of 200 ° C for 1 h to obtain a reduced graphene-encapsulated foamed nickel coated with PMMA.
  • the obtained surface-coated PMMA-reduced graphene-encapsulated foamed nickel was placed in a dilute hydrochloric acid solution having a concentration of 4 mol/L, and magnetically stirred for 8 hours to completely etch the nickel foam
  • the coated foam reduces graphene.
  • the obtained PMMA-coated foam-reduced graphene is immersed in an acetone solution at 60 ° C for 2 hours to remove PMMA, thereby obtaining PMMA-removed foam-reduced graphene, which is purified by deionized water washing, freeze-drying, and heat treatment.
  • the foam reduces graphene.
  • the foamed reduced graphene prepared by the above method has a uniform cavity distribution and a moderate cavity diameter, which is favorable for improving the performance of the finally obtained lithium metal electrode.
  • the present embodiment provides a lithium metal secondary battery negative electrode 300, which includes at least one lithium metal electrode 100 provided by any of the above embodiments. .
  • the cell cavity 11 of the foam electrode substrate 1 can effectively limit the volume expansion of the lithium metal particles 2 during charge and discharge and increase the surface area of the lithium metal electrode, reducing the lithium dendrites.
  • the battery is short-circuited due to the lithium dendrite piercing the separator. Therefore, the lithium metal electrode 100 can be used as the negative electrode of the lithium metal secondary battery, thereby effectively improving the stability, cycle performance, and largeness of the lithium metal secondary battery. Fast current charging capability and safety performance.
  • the number of the lithium metal electrodes 100 should be based on the size of the lithium metal electrode 100, the capacity of the lithium metal electrode 100, the size of the lithium metal secondary battery negative electrode 300, and lithium.
  • the capacity requirement of the metal secondary battery 300 is determined.
  • the lithium metal electrode 100 can be directly used as a lithium metal secondary battery negative electrode.
  • the lithium metal secondary battery negative electrode 300 includes a plurality of lithium metal electrodes 100, for example, two, four, five, six, eight, ten, fifteen, etc., in order to facilitate the lithium metal secondary battery negative electrode 300
  • the lithium metal secondary battery negative electrode may further include: a substrate 3 for supporting a lithium metal electrode.
  • the material of the substrate 3 may be a current collector material commonly used in the art, such as copper foil, nickel foil, or the like.
  • the lithium metal electrode 100 can be made into a preform of a certain size and a certain capacity. In use, a certain amount of the lithium metal electrode 100 is loaded onto the substrate 3 according to the requirements of the negative electrode of the lithium metal secondary battery to obtain a lithium metal twice. Battery negative electrode 300.
  • the arrangement of the plurality of lithium metal electrodes 100 on the substrate is not particularly limited, and may be arranged irregularly or according to a certain degree.
  • a plurality of lithium metal electrodes 100 are disposed on the substrate 3 in an array form, and the fabrication of the lithium metal secondary battery negative electrode 300 is facilitated by an array.
  • FIG. 9 shows a lithium metal secondary battery negative electrode 300 including six lithium metal electrodes 100, which are arranged on the substrate 3 in the form of a 3 ⁇ 2 (length ⁇ width) array.
  • the present embodiment provides a lithium metal secondary battery comprising: a casing, an electrolyte, a positive electrode, a negative electrode, and a separator, wherein the negative electrode is the lithium metal secondary battery negative electrode provided in the third embodiment.
  • the metal lithium particles are distributed in the pore cavity of the foam electrode substrate, and the pore cavity of the foam electrode substrate can limit the volume expansion of the lithium metal particles and inhibit the growth of lithium dendrites. Therefore, the lithium metal secondary battery using the lithium metal secondary battery negative electrode as a negative electrode has good stability, cycle performance, high current fast charging capability, and safety performance.
  • the lithium metal secondary battery provided in this embodiment may be any battery conventionally using metal lithium as a negative electrode, including but not limited to a lithium metal air battery and a lithium sulfur battery.
  • the method for preparing a lithium metal secondary battery by using the lithium metal secondary battery negative electrode provided in the third embodiment mainly includes the negative electrode of the lithium metal secondary battery provided in the third embodiment, the positive electrode of the lithium metal secondary battery, the separator, the electrolyte, the outer casing, and the like.
  • the steps of assembling, sealing, and pre-charging the components are the same as the conventional methods for preparing lithium metal secondary batteries in the art, and are not described herein again.
  • the embodiment of the present invention utilizes the feature that the foam electrode substrate has a cavity cavity, and provides a lithium metal electrode using the foam electrode substrate as an electrode substrate.
  • the pore cavity of the foam electrode substrate can effectively limit the volume expansion of the metal lithium particles distributed therein, and effectively inhibit the growth of lithium dendrites, and therefore, the lithium metal secondary battery using the lithium metal electrode as the negative electrode has good stability performance. , cycle performance, high current fast charging capability and safety performance.
  • the surface of the metal lithium particles in the lithium metal electrode provided by the embodiment of the invention is further coated with a protective layer formed of a good lithium ion conductor material, and the metal lithium particles are prevented from being in contact with the external atmosphere while ensuring the reactivity of the metal lithium particles.
  • the lithium metal electrode provided by the embodiment of the invention is applicable to various lithium metal secondary batteries using a metal lithium as a negative electrode, and the lithium metal electrode provided by the embodiment of the invention has a simple preparation method, low cost and wide application range.

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Abstract

一种锂金属电极及其制备方法、锂金属二次电极负极、电池，属于锂电池技术领域。其中，锂金属电极（100）包括：具有多个孔道空腔（11）的泡沫电极基体（1），以及分布在所述泡沫电极基体（1）的至少一个孔道空腔（11）内的金属锂颗粒（2）；所述泡沫电极基体（1）的材料为泡沫金属材料或者碳泡沫材料。泡沫电极基体（1）的孔道空腔（11）能够有效限制金属锂颗粒（2）在充放电过程中的体积膨胀并且减少锂枝晶的生成，有效提高以该锂金属电极（100）作为负极的锂金属二次电池的稳定性能、循环性能、快速充电性能以及安全性能。

Description

锂金属电极及其制备方法、锂金属二次电极负极、电池
本申请要求于2016年5月12日提交中国专利局、申请号为201610319583.3、发明名称为“锂金属电极及其制备方法、锂金属二次电极负极、电池”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明涉及锂电池技术领域，特别涉及一种锂金属电极及其制备方法、锂金属二次电极负极、电池。
背景技术
随着便携电子设备和电动汽车的不断发展，高能量密度电池的研发变得日益重要。锂金属二次电池是以锂金属电极作为负极的一种可充电锂电池。根据正极材料的不同，锂金属二次电池主要包括锂金属空气电池和锂硫电池。由于金属锂具有极高的理论比容量(3860mAh/g)、最负的还原电位(-3.04V，相对于氢标电位)以及极小的密度(0.59g/cm3)，因此锂金属二次电池的能量密度远远大于其他电池体系(例如锂金属空气电池的理论能量密度能够达到11140Wh/kg，锂硫电池的理论能量密度能够达到2680Wh/kg)。
目前用于锂金属二次电池的锂金属电极主要采用片状金属锂或者将金属锂颗粒涂覆在片状电极基体上的形式。
在实现本发明的过程中，发明人发现现有技术至少存在以下问题：现有的用于锂金属二次电池的锂金属电极在充放电过程中会发生体积膨胀，影响锂金属二次电池的稳定性和循环性能；同时，在长期充放电过程中，锂会沉积在负极表面形成锂枝晶，当锂枝晶生长到能够刺穿锂金属二次电池的隔膜时，将导致短路进而引起爆炸。
发明内容
为了解决现有技术的问题，本发明实施例提供了一种在充放电过程中体积变化小、枝晶产生量少的锂金属电极及其制备方法、锂金属二次电极负极、电池。
具体而言，包括以下的技术方案：
第一方面，提供了一种锂金属电极，包括：具有多个孔道空腔的泡沫电极基体，以及分布在所述泡沫电极基体的至少一个孔道空腔内的金属锂颗粒；所述泡沫电极基体的材料为泡沫金属材料或者碳泡沫材料。
本发明实施例提供的锂金属电极中，电极基体为具有多个孔道空腔结构的泡沫电极基体，金属锂颗粒分布在泡沫电极基体的至少一个孔道空腔内。泡沫电极基体的孔道空腔能够有效限制金属锂颗粒在充放电过程中的体积膨胀，从而有效提高以该锂金属电极作为负极的锂金属二次电池的稳定性和循环性能。同时，泡沫电极基体的孔道空腔还能够有效增大锂金属电极的表面积，不仅极大提升了以该锂金属电极作为负极的锂金属二次电池的大电流快速充电能力，还有效减少了锂枝晶的生成，避免由于锂枝晶刺穿隔膜而导致的电池短路问题，提高 锂金属二次电池的安全性能。
结合第一方面，需要说明的是，可以有20％以上的所述多个孔道空腔内分布有所述金属锂颗粒。也可以有30％以上、40％以上、50％以上、60％以上、70％以上、80％以上或者90％以上的所述多个孔道空腔内分布有金属锂颗粒。通过控制分布有金属锂颗粒的孔道空腔的百分比，可以提高以本发明实施例提供的锂金属电极作为负极的锂金属二次电池的性能。
结合第一方面，可以理解的是，由于制备工艺条件的限制，在所述泡沫电极基体上的所述多个孔道空腔以外的区域内也分布有所述金属锂颗粒。其中，分布在所述泡沫电极基体的孔道空腔内的所述金属锂颗粒的数量大于分布在所述多个孔道空腔以外的区域内的所述金属锂颗粒的数量；或者，分布在所述泡沫电极基体的孔道空腔内的所述金属锂颗粒的密度大于分布在所述多个孔道空腔以外的区域内的所述金属锂颗粒的密度。
由于孔道空腔以外的区域不能够限制金属锂颗粒的体积膨胀，也不能抑制锂枝晶的形成，因此，当泡沫电极基体上的多个孔道空腔以外的区域内也分布有金属锂颗粒时，通过控制分布在泡沫电极基体的孔道空腔内的金属锂颗粒的数量、密度与分布在多个孔道空腔以外的区域内的金属锂颗粒的数量、密度之间的关系，来保证本发明实施例提供的锂金属电极的性能。
结合第一方面，所述泡沫电极基体的孔道空腔的直径可以为100纳米～50微米。如果泡沫电极基体的孔道空腔的直径过小，金属锂颗粒不容易进入孔道空腔内，从而增加本实施例的锂金属电极制备的难度。如果泡沫电极基体的孔道空腔的直径过大，则在锂金属电极尺寸一定的情况下，泡沫电极基体的孔道空腔的数量会减少，不能够对金属锂颗粒的体积膨胀起到很好的限制作用，从而影响锂金属电极的性能。
结合第一方面，为了保证所述金属锂颗粒的化学稳定性，避免所述金属锂颗粒与外界气氛接触发生反应，所述锂金属电极还包括：包覆在所述金属锂颗粒表面的保护层；所述保护层的材料为锂离子良导体材料。其中，所述保护层的材料可以选自Li2CO3、Li4SiO4、LiF、Li3PO3、TiO2、Li2TiO3、Li4Ti5O12、SiO2、SnO2、SiC、LiAlO2、Al2O3、NiS、CuS、FeS、MnS、Ag2S以及TiS2中的至少一种。
结合第一方面，所述泡沫金属材料选自泡沫镍、泡沫铜、泡沫钛以及泡沫铁中的至少一种。所述碳泡沫材料选自泡沫碳、泡沫碳纳米管以及泡沫石墨烯中的至少一种。具体来说，所述泡沫石墨烯所用的石墨烯选自氧化石墨烯、还原石墨烯以及元素掺杂石墨烯中的至少一种。所述氧化石墨烯可以为共价键功能化石墨烯以及非共价键功能化石墨烯中的至少一种。所述元素掺杂石墨烯中掺杂的元素选自氮、硫以及磷中的至少一种。需要说明的是，采用元素掺杂石墨烯更有利于提高以本发明实施例提供的锂金属电极作为负极的锂金属二次电池的快速充电能力。
第二方面，提供了一种锂金属电极的制备方法，包括：
准备具有多个孔道空腔的泡沫电极基体；
在所述泡沫电极基体的至少一个孔道空腔内涂覆金属锂颗粒；
所述泡沫电极基体的材料为泡沫金属材料或者碳泡沫材料。
采用本发明实施例提供的制备方法制备得到的锂金属电极中，电极基体为具有多个孔道空腔结构的泡沫电极基体，金属锂颗粒分布在泡沫电极基体的至少一个孔道空腔内。泡沫电极基体的孔道空腔能够有效限制金属锂颗粒在充放电过程中的体积膨胀，并且抑制锂枝晶的生长，从而有效提高以由本发明实施例的制备方法制备得到的锂金属电极作为负极的锂金属 二次电池的稳定性能、循环性能、快速充电能力以及安全性能。
结合第二方面，需要说明的是，可以有20％以上的所述多个孔道空腔内分布有金属锂颗粒。也可以有50％、60％、70％或者80％以上的所述多个孔道空腔内分布有金属锂颗粒。
结合第二方面，可以采用气相沉积法涂覆所述金属锂颗粒。采用气相沉积法能够将金属锂颗粒均匀地涂敷在泡沫电极基体的孔道空腔内。气相沉积法具体可以为真空蒸镀的方法；所述真空蒸镀的条件为：将所述泡沫电极基体固定在金属锂颗粒蒸发源的正上方，在1×10-2帕以下的压力下，用电流为50～500毫安、电压为3～12千伏的电子束轰击所述金属锂颗粒蒸发源，轰击时间为5～50分钟，所述泡沫电极基体与所述金属锂颗粒蒸发源的距离为30～150厘米。
采用上述真空蒸镀条件涂覆得到的金属锂颗粒分布更加均匀，有利于提高所得锂金属电极的性能。
结合第二方面，为了保证制备得到的锂金属电极中所述金属锂颗粒的化学稳定性，避免所述金属锂颗粒与外界气氛接触发生反应，所述制备方法还包括：在所述金属锂颗粒的表面涂覆保护层；所述保护层的材料为锂离子良导体材料。其中，所述保护层的材料选自Li2CO3、Li4SiO4、LiF、Li3PO3、TiO2、Li2TiO3、Li4Ti5O12、SiO2、SnO2、SiC、LiAlO2、Al2O3、NiS、CuS、FeS、MnS、Ag2S以及TiS2中的至少一种。
结合第二方面，所述泡沫金属材料选自泡沫镍、泡沫铜、泡沫钛以及泡沫铁中的至少一种。所述碳泡沫材料选自泡沫碳、泡沫碳纳米管以及泡沫石墨烯中的至少一种。具体来说，所述泡沫石墨烯所用的石墨烯选自氧化石墨烯、还原石墨烯以及元素掺杂石墨烯中的至少一种。所述氧化石墨烯选自共价键功能化石墨烯以及非共价键功能化石墨烯中的至少一种。所述元素掺杂石墨烯中掺杂的元素选自氮、硫以及磷中的至少一种。
结合第二方面，需要说明的是，可以采用气相沉积法将所述保护层涂覆在所述金属锂颗粒表面。采用气相沉积法能够将保护层均匀地涂敷在金属锂颗粒表面。
第三方面，提供了一种锂金属二次电池负极，包括：至少一个第一方面所述的锂金属电极。
由于本发明实施例第一方面提供的锂金属电极中，泡沫电极基体的孔道空腔能够有效限制金属锂颗粒在充放电过程中的体积膨胀并且抑制锂枝晶的生成，因此，将该锂金属电极作为锂金属二次电池的负极，能够有效提高锂金属二次电池的稳定性能、循环性能、大电流快速充电能力以及安全性能。
结合第三方面，需要说明的是，当所述锂金属二次电池负极包括多个所述锂金属电极时，为了便于所述锂金属二次电池负极的使用，所述锂金属二次电池负极还包括：用于负载所述锂金属电极的基底。多个所述锂金属电极可以以阵列的形式设置在所述基底上。
第四方面，提供了一种锂金属二次电池，包括：外壳、电解液、正极、负极以及隔膜，所述负极为第三方面所述的锂金属二次电池负极。
由于本发明实施例第三方面提供的锂金属二次电池负极中，金属锂颗粒分布在泡沫电极基体的孔道空腔内，泡沫电极基体的孔道空腔能够限制锂金属颗粒的体积膨胀以及抑制锂枝晶的生长，因此，以该锂金属二次电池负极作为负极的锂金属二次电池具有良好的稳定性、循环性能、大电流快速充电能力以及安全性能。
结合第四方面。可以理解的是，所述锂金属二次电池为锂金属空气电池或者锂硫电池。
附图说明
图1为实施例一提供的一种锂金属电极的结构示意图；
图2为实施例一提供的另一种锂金属电极的结构示意图；
图3为实施例一提供的锂金属电极中泡沫电极基体的横截面的示意图；
图3-1为长方形的横截面的示意图；
图3-2为正方形的横截面的示意图；
图3-3为圆形的横截面的示意图；
图3-4为C字型的横截面的示意图；
图4为实施例一中，泡沫电极基体的材料为泡沫石墨烯时，金属锂颗粒在泡沫石墨烯的孔道空腔中分布情况的扫描电镜照片；
图5为实施例二提供的一种锂金属电极的制备方法的流程示意图；
图6为实施例二提供的一种锂金属电极的制备方法的扫描电镜照片；
图7为实施例二中，泡沫还原石墨烯的制备方法的原理图；
图8为实施例三提供的一种锂金属二次电池负极的结构示意图；
图9为实施例三提供的另一种锂金属二次电池负极的结构示意图。
其中，图中的附图标记100表示锂金属电极，1表示泡沫电极基体，11表示孔道空腔，2表示金属锂颗粒，300表示锂金属二次电池负极，3表示基底。
具体实施方式
为使本发明的目的、技术方案和优点更加清楚，下面将结合附图对本发明实施方式作进一步地详细描述。除非另有定义，本发明实施例所用的所有技术术语均具有与本领域技术人员通常理解的相同的含义。
实施例一
参见图1，本实施例提供了一种锂金属电极100，该锂金属电极100包括：具有多个孔道空腔11的泡沫电极基体1，以及分布在泡沫电极基体1的至少一个孔道空腔11内的金属锂颗粒2。泡沫电极基体1的材料为泡沫金属材料或者碳泡沫材料。
泡沫金属材料以及碳泡沫材料为具有多个孔道空腔结构的三维立体材料。本实施例中，以泡沫金属材料或者碳泡沫材料作为锂金属电极的电极基体，将金属锂颗粒2分布在泡沫电极基体1的至少一个孔道空腔11内，泡沫电极基体1的孔道空腔11能够有效限制金属锂颗粒2在充放电过程中的体积膨胀，从而有效提高以该锂金属电极100作为负极的锂金属二次电池的稳定性和循环性能。同时，泡沫电极基体1的孔道空腔11还能够有效增大锂金属电极100的表面积，不仅极大提升了以该锂金属电极作为负极的锂金属二次电池的大电流快速充电能力，还有效减少了锂枝晶的生成，避免由于锂枝晶刺穿隔膜而导致的电池短路问题，提高锂金属二次电池的安全性能。
进一步地，为了保证本实施例提供的锂金属电极100的性能，应当控制分布有金属锂颗粒的孔道空腔的百分比，可选地，20％以上的孔道空腔11内分布有金属锂颗粒，或者25％以上、30％以上、35％以上、40％以上、45％以上，50％以上、55％以上、60％以上、65％以上、 70％以上、75％以上、80％以上、85％以上、90％以上、95％以上、100％的孔道空腔内分布有金属锂颗粒。
进一步地，由于制备工艺条件的限制，有些情况下不能保证金属锂颗粒2全部分布于泡沫电极基体1的孔道空腔11内，如图2所示，在泡沫电极基体1上的多个孔道空腔11以外的区域内，例如泡沫电极基体的表面，也可能分布有金属锂颗粒2。但是，孔道空腔11以外的区域不能够限制金属锂颗粒2的体积膨胀，也不能抑制锂枝晶的形成，因此，为了保证本实施例的锂金属电极100的性能，当泡沫电极基体1上的多个孔道空腔11以外的区域内也分布有金属锂颗粒2时，可选地，分布在泡沫电极基体1的孔道空腔11内的金属锂颗粒的数量大于分布在多个孔道空腔11以外的区域内的金属锂颗粒2的数量，或者，分布在泡沫电极基体的孔道空腔内的金属锂颗粒的密度大于分布在多个孔道空腔以外的区域内的金属锂颗粒的密度。或者，在分布在泡沫电极基体1的孔道空腔11内的金属锂颗粒2的数量大于分布在多个孔道空腔11以外的区域内的金属锂颗粒2的数量的同时，分布在泡沫电极基体的孔道空腔1内的金属锂颗粒2的密度也大于分布在多个孔道空腔11以外的区域内的金属锂颗粒2的密度。
进一步地，本实施例提供的锂金属电极100中，泡沫电极基体1的孔道空腔11的直径可以为100纳米～50微米，例如200纳米、300纳米、400纳米、500纳米、600纳米、700纳米、800纳米、900纳米、1微米、5微米、10微米、15微米、20微米、25微米、30微米、35微米、40微米、45微米等。如果泡沫电极基体1的孔道空腔11的直径过小，金属锂颗粒2不容易进入孔道空腔11内，从而增加本实施例的锂金属电极100制备的难度。如果泡沫电极基体的孔道空腔的直径过大，则在锂金属电极100尺寸一定的情况下，泡沫电极基体1的孔道空腔11的数量会减少，不能够对金属锂颗粒2的体积膨胀起到很好的限制作用，从而影响锂金属电极的性能。
进一步地，本实施例提供的锂金属电极100中，金属锂颗粒2可以为直径为100纳米以下的纳米金属锂颗粒，例如直径为10纳米、20纳米、30纳米、40纳米、50纳米、60纳米、70纳米、80纳米或者90纳米的金属锂颗粒。采用纳米金属锂颗粒能够提高锂金属二次电池的容量、快速充电性能以及在高温环境中的循环性能。
进一步地，本实施例提供的锂金属电极100中，泡沫电极基体1横截面的形状没有严格的限制，本领域常规技术手段均可，例如长方形(如图3-1所示)、正方形(如图3-2所示)、圆形(如图3-3所示)、C字型(如图3-4所示)等。
进一步地，本实施例提供的锂金属电极100中，为了保证金属锂颗粒2的化学稳定性，避免金属锂颗粒2与外界气氛接触发生反应，还可以在金属锂颗粒2表面包覆保护层(图中未示出)。其中，保护层的材料为锂离子良导体材料，锂离子良导体材料具有良好的锂离子导通效果，在避免金属锂颗粒与外界气氛接触的同时，保证金属锂颗粒的反应活性，从而保证以本实施例提供的锂金属电极100作为负极的锂金属二次电池的性能。其中，保护层的材料可以为Li2CO3、Li4SiO4、LiF、Li3PO3、TiO2、Li2TiO3、Li4Ti5O12、SiO2、SnO2、SiC、LiAlO2、Al2O3、NiS、CuS、FeS、MnS、Ag2S以及TiS2中的至少一种。
进一步地，本实施例提供的锂金属电极100中，泡沫电极基体1的材料可以选择不可嵌入锂的材料。具体来说，泡沫金属材料可以为泡沫镍、泡沫铜、泡沫钛或者泡沫铁，可以单独使用一种泡沫金属材料，也可以多种泡沫金属材料配合使用。碳泡沫材料可以为泡沫碳、 泡沫碳纳米管或者泡沫石墨烯，可以单独使用一种碳泡沫材料，也可以多种碳泡沫材料配合使用。
在上述各类泡沫金属材料和碳泡沫材料中，泡沫石墨烯是由石墨烯片层堆叠形成的具有骨架结构和孔道空腔结构的三维立体材料。与其它泡沫金属材料和碳泡沫材料相比，泡沫石墨烯具有更高的强度、更优越的电学性能，因此，本实施例中，泡沫电极基体的材料优选采用泡沫石墨烯。金属锂颗粒2在泡沫石墨烯的孔道空腔11内分布情况如图4所示，金属锂颗粒2均匀的分布在泡沫石墨烯的孔道空腔11内。泡沫石墨烯所用的石墨烯可以为氧化石墨烯、还原石墨烯以及元素掺杂石墨烯中的至少一种。其中，氧化石墨烯可以为共价键功能化石墨烯以及非共价键功能化石墨烯中的至少一种；元素掺杂石墨烯中掺杂的元素可以为氮、硫以及磷中的至少一种。需要说明的是，由于元素掺杂改变了石墨烯的分子结构，使得以元素掺杂石墨烯作为泡沫电极基体1的材料的锂金属负极具有物理和化学双重储锂功能，因此采用元素掺杂石墨烯更有利于提高以本实施例提供的锂金属电极作为负极的锂金属二次电池的快速充电能力。
实施例二
本实施例提供了一种锂金属电极的制备方法，参见图5并结合图6，该制备方法包括以下步骤：
步骤201，准备具有多个孔道空腔的泡沫电极基体。
步骤202，在泡沫电极基体的至少一个孔道空腔内涂覆金属锂颗粒；其中，泡沫电极基体的材料为泡沫金属材料或者碳泡沫材料。
采用本实施例提供的制备方法制备得到的锂金属电极中，电极基体为具有多个孔道空腔结构的泡沫电极基体，金属锂颗粒分布在泡沫电极基体的至少一个孔道空腔内。泡沫电极基体的孔道空腔能够有效限制金属锂颗粒在充放电过程中的体积膨胀，从而有效提高以由本实施例的制备方法制备得到的锂金属电极作为负极的锂金属二次电池的稳定性和循环性能。同时，泡沫电极基体的孔道空腔还能够有效增大锂金属电极的表面积，不仅极大提升了以上述锂金属电极作为负极的锂金属二次电池的大电流快速充电能力，还有效减少了锂枝晶的生成，避免由于锂枝晶刺穿隔膜而导致的电池短路问题，提高锂金属二次电池的安全性能。
进一步地，为了保证制备得到的锂金属电极的性能，应当控制涂覆条件来控制使分布有金属锂颗粒的孔道空腔的百分比达到一定的数值，例如，可以使20％以上的孔道空腔11内分布有金属锂颗粒，或者25％以上、30％以上、35％以上、40％以上、45％以上，50％以上、55％以上、60％以上、65％以上、70％以上、75％以上、80％以上、85％以上、90％以上、95％以上、100％的孔道空腔内分布有金属锂颗粒。
进一步地，由于涂覆工艺的限制，可能会将金属锂颗粒涂敷在泡沫电极基体上的多个孔道空腔以外的区域内。但是，由于孔道空腔以外的区域不能够限制金属锂颗粒的体积膨胀并且不能抑制锂枝晶的形成，因此为了保证本实施例制备得到的锂金属电极的性能，在完成金属锂颗粒的涂覆之后，可以去除全部或者部分涂覆在泡沫电极基体上的多个孔道空腔以外的区域内的金属锂颗粒，使涂覆在泡沫电极基体的孔道空腔内的金属锂颗粒的数量大于涂覆在多个孔道空腔以外的区域内的金属锂颗粒的数量，或者使涂覆在泡沫电极基体的孔道空腔内的金属锂颗粒的密度大于涂覆在多个孔道空腔以外的区域内的金属锂颗粒的密度，或者使涂 覆在泡沫电极基体的孔道空腔内的金属锂颗粒的数量和密度均大于涂覆在多个孔道空腔以外的区域内的金属锂颗粒。可以采用气体吹扫的方法去除涂覆在泡沫电极基体上的多个孔道空腔以外的区域内的金属锂颗粒。
进一步地，金属锂颗粒的涂覆方法本实施例不作特殊限定，本领域的常用的涂覆金属锂颗粒的方法均可，例如气相沉积法。气相沉积法具体可以为物理气相沉积法，更具体地，可以为真空蒸镀法。真空蒸镀的具体条件本实施例不作特殊限定，领域常规技术手段均可。可以通过控制真空蒸镀的时间来控制金属锂颗粒涂覆的厚度。
本实施例提供的制备方法中，一个可选的利用真空蒸镀涂覆锂金属颗粒的条件为：将泡沫电极基体固定在金属锂颗粒蒸发源的正上方，在1×10-2帕以下的压力下，用电流为50～500毫安、电压为3～12千伏的电子束轰击金属锂颗粒蒸发源，轰击时间为5～50分钟，泡沫电极基体与金属锂颗粒蒸发源的距离为30～150厘米。
另一个可选的利用真空蒸镀涂覆锂金属颗粒的条件为：将金属锂颗粒置于真空蒸镀设备的坩锅内作为蒸发源，将泡沫电极基体水平固定在蒸发源正上方并且距离蒸发源80厘米位置处。然后进行抽真空处理，当压力下降到1×10-3帕时，稳定在该压力并启动电子束轰击蒸发源锂金属颗粒，开始进行蒸镀，其中电子束电压为7.5千伏，电流为70毫安，蒸镀的时间为20分钟。蒸镀结束后，真空状态下自然冷却，通气出炉，即完成了金属锂颗粒的涂覆。
采用上述真空蒸镀条件涂覆得到的金属锂颗粒分布更加均匀，有利于提高所得锂金属电极的性能。
进一步地，为了保证金属锂颗粒的化学稳定性，避免金属锂颗粒与外界气氛接触发生反应，本实施例提供的制备方法中，参见图5，在步骤202之后，还可以包括：步骤203，在金属锂颗粒的表面涂覆保护层，其中，保护层的材料为锂离子良导体材料。锂离子良导体材料具有良好的锂离子导通效果，在避免金属锂颗粒与外界气氛接触的同时，保证金属锂颗粒的反应活性，从而保证以由本实施例提供的制备方法制备得到的锂金属电极作为负极的锂金属二次电池的性能。其中，保护层的材料可以为Li2CO3、Li4SiO4、LiF、Li3PO3、TiO2、Li2TiO3、Li4Ti5O12、SiO2、SnO2、SiC、LiAlO2、Al2O3、NiS、CuS、FeS、MnS、Ag2S以及TiS2中的至少一种。涂覆保护层的方法本实施例不作特殊限定，本领域常规技术手段均可，例如气相沉积法。气相沉积法具体可以为物理气相沉积法，更具体地，可以为真空蒸镀法。
以LiF为例，一个可选的利用真空蒸镀涂覆保护层的条件为：将LiF颗粒置于真空蒸镀设备的坩锅内作为蒸发源，将涂覆有金属锂颗粒的泡沫电极基体水平固定在离蒸发源正上方并且距离蒸发源30～150厘米处；然后进行抽真空处理，当压力下降到1×10-2帕以下时，启动电子束轰击蒸发源LiF颗粒，开始进行蒸镀。其中电子束电压为3～12千伏，电流为50～500毫安，蒸镀的时间为5～50分钟。蒸镀结束后，真空状态下自然冷却，通气出炉，即得到涂覆有保护层的锂金属电极。
以LiF为例，另一个可选的利用真空蒸镀涂覆保护层的条件为：将LiF颗粒置于真空蒸镀设备的坩锅内作为蒸发源，将涂覆有金属锂颗粒的泡沫电极基体水平固定在离蒸发源正上方并且距离蒸发源80厘米处；然后进行抽真空处理，当压力下降到1×10-3帕时，启动电子束轰击蒸发源LiF颗粒，开始进行蒸镀。其中电子束电压为7.5千伏，电流为70毫安，蒸镀的时间为5分钟。蒸镀结束后，真空状态下自然冷却，通气出炉，即得到涂覆有保护层的锂金属电极。
进一步地，本实施例提供的制备方法中，步骤201中的准备具有多个孔道空腔的泡沫电极基体具体包括制备泡沫电极基体，按照锂金属二次电池对锂金属电极的要求对泡沫电极基体的尺寸进行裁剪，以及除去泡沫电极基体上的杂质等步骤。对于一些可以直接购买得到的泡沫电极基体，可以省去制备泡沫电极基体的步骤。其中，除去泡沫电极基体上的杂质可以使金属锂颗粒更紧密的附着在泡沫电极基体上，可以采用离子束轰击的方法除去泡沫电极基体上的杂质。
一个可选的离子束轰击条件为：在真空压力为0.1～10帕的环境下，用电压为150～300伏、电流为0.1～0.5安培的离子束轰击泡沫电极基体，轰击时间为1～20分钟。
另一个可选的离子束轰击条件为：在真空压力为5帕的环境下，用电压为200伏、电流为0.2安培的离子束轰击泡沫电极基体，轰击时间为5分钟。
进一步地，本实施例提供的制备方法中，泡沫电极基体的材料可以选择不可嵌入锂的材料。具体来说，泡沫金属材料可以为泡沫镍、泡沫铜、泡沫钛或者泡沫铁，可以单独使用一种泡沫金属材料，也可以多种泡沫金属材料配合使用。碳泡沫材料可以为泡沫碳、泡沫碳纳米管或者泡沫石墨烯，可以单独使用一种碳泡沫材料，也可以多种碳泡沫材料配合使用。其中，泡沫石墨烯所用的石墨烯可以为氧化石墨烯、还原石墨烯以及元素掺杂石墨烯中的至少一种。氧化石墨烯可以为共价键功能化石墨烯以及非共价键功能化石墨烯中的至少一种；元素掺杂石墨烯中掺杂的元素可以为氮、硫以及磷中的至少一种。
上述的泡沫镍、泡沫铜、泡沫钛以及泡沫铁等泡沫金属材料可以直接购买得到，也可以由以下方法制备得到：以有机泡沫材料，例如聚氨酯泡沫材料作为模板，在有机泡沫材料上沉积金属，然后通过加热分解或者有机溶剂溶解的方法将有机泡沫材料去除，即得到泡沫金属材料。
上述的泡沫碳可以通过在有机泡沫材料，例如聚氨酯泡沫上沉积碳，再利用加热分解或者有机溶解将有机泡沫材料去除的方法制备得到。泡沫石墨烯可以通过对石墨烯进行冷冻干燥、使石墨烯冻干膨胀获得，也可以通过以泡沫金属材料、例如泡沫镍为模板，在金属泡沫材料上沉积石墨烯，然后将泡沫金属材料去除的方法获得。具体来说，泡沫还原石墨烯、泡沫元素掺杂石墨烯可以通过对泡沫氧化石墨烯进行还原或者元素掺杂获得。
以泡沫还原石墨烯为例，参见图7，一种可选的制备泡沫还原石墨烯的方法为：以泡沫镍(可以采用密度为420～440g/cm3、厚度为1.6mm～2.0mm的泡沫镍)作为模板，将泡沫镍置于石英真空高温管式烧结炉中，在保护气体气氛下升温至800～1200℃并保温30～60min，然后向上述烧结炉不断通入甲烷气体，甲烷气体的通入时间为8～12min，再将上述烧结炉以80～100℃/min的速率快速冷却至室温，得到被氧化石墨烯包覆的泡沫镍。将所得被氧化石墨烯包裹的泡沫镍，浸入到质量分数为3％～5％的聚甲基丙烯酸甲酯(PMMA)和乳酸乙酯混合溶液中5～10min，将氧化石墨烯还原，然后在室温下自然干燥，再在温度为150～200℃的条件下保温0.5～lh，即得到表面包覆PMMA的还原石墨烯包裹的泡沫镍。将所得表面包覆PMMA的还原石墨烯包裹的泡沫镍置于浓度为3～4mol/L的稀盐酸溶液中，通过磁力搅拌4～8h，使泡沫镍被盐酸完全刻蚀掉，得到去除泡沫镍模板的PMMA包覆的泡沫还原石墨烯。然后将所得到的PMMA包覆的泡沫还原石墨烯置于55～65℃的丙酮溶液中浸泡1～2h以除去PMMA，得到去除PMMA的泡沫还原石墨烯，在经去离子水洗涤、冷冻干燥、热处理得到纯净的泡沫还原石墨烯。
以泡沫还原石墨烯为例，参见图7，另一种可选的制备泡沫还原石墨烯的方法为：以泡沫镍作为模板，将泡沫镍置于石英真空高温管式烧结炉中，在保护气体气氛下升温至1000℃并保温60min，然后向上述烧结炉不断通入甲烷气体，甲烷气体的通入时间为10min，再将上述烧结炉以80℃/min的速率快速冷却至室温，得到被氧化石墨烯包覆的泡沫镍。将所得被氧化石墨烯包裹的泡沫镍，浸入到质量分数为3％～5％的聚甲基丙烯酸甲酯(PMMA)和乳酸乙酯混合溶液中10min，将氧化石墨烯还原，然后在室温下自然干燥，再在温度为200℃的条件下保温lh，即得到表面包覆PMMA的还原石墨烯包裹的泡沫镍。将所得表面包覆PMMA的还原石墨烯包裹的泡沫镍置于浓度为4mol/L的稀盐酸溶液中，通过磁力搅拌8h，使泡沫镍被盐酸完全刻蚀掉，得到去除泡沫镍模板的PMMA包覆的泡沫还原石墨烯。然后将所得到的PMMA包覆的泡沫还原石墨烯置于60℃的丙酮溶液中浸泡2h以除去PMMA，得到去除PMMA的泡沫还原石墨烯，在经去离子水洗涤、冷冻干燥、热处理得到纯净的泡沫还原石墨烯。
以上述方法制备得到的泡沫还原石墨烯中孔道空腔分布均匀、孔道空腔直径适中，有利于提高最终得到的锂金属电极的性能。
实施例三
参见图8，并结合图1和图2，本实施例提供了一种锂金属二次电池负极300，该锂金属二次电池负极300包括：至少一个上述任一实施例提供的锂金属电极100。
由于上述实施例提供的锂金属电极100中，泡沫电极基体1的孔道空腔11能够有效限制金属锂颗粒2在充放电过程中的体积膨胀并且增大锂金属电极的表面积，减少锂枝晶的生成，避免由于锂枝晶刺穿隔膜而导致的电池短路问题，因此，将该锂金属电极100作为锂金属二次电池的负极，能够有效提高锂金属二次电池的稳定性能、循环性能、大电流快速充电能力以及安全性能。
进一步地，本实施例提供的锂金属二次电池负极300中，锂金属电极100的数量应当根据锂金属电极100的尺寸、锂金属电极100的容量、锂金属二次电池负极300的尺寸以及锂金属二次电池300的容量要求来确定。当一个锂金属电极100的尺寸和容量能够满足锂金属二次电池负极300的要求时，可以直接以该锂金属电极100作为锂金属二次电池负极。当锂金属二次电池负极300包括多个锂金属电极100时，例如2个、4个、5个、6个、8个、10个、15个等，为了便于锂金属二次电池负极300的使用，该锂金属二次电池负极还可以包括：用于负载锂金属电极的基底3。基底3的材料可以为本领域常用的集流体的材料，例如铜箔、镍箔等。可以将锂金属电极100制成一定尺寸和一定容量的预制件，在使用时，根据锂金属二次电池负极的要求，将一定数量的锂金属电极100负载到基底3上从而得到锂金属二次电池负极300。
本实施例中，当锂金属二次电池负极300包括多个锂金属电极100时，多个锂金属电极100在基底上的排列方式没有特殊的限定，可以无规则的排列，也可以按照一定的顺序排列，可选的，将多个锂金属电极100以阵列的形式设置在基底3上，采用阵列的形式便于锂金属二次电池负极300的制作。例如，图9示出了一种包括6个锂金属电极100的锂金属二次电池负极300，6个锂金属电极100以3×2(长×宽)阵列的形式排列在基底3上。
实施例四
本实施例提供了一种锂金属二次电池，该锂金属二次电池包括：外壳、电解液、正极、负极以及隔膜，其中，负极为实施例三提供的锂金属二次电池负极。
由于实施例三提供的锂金属二次电池负极中，金属锂颗粒分布在泡沫电极基体的孔道空腔内，泡沫电极基体的孔道空腔能够限制锂金属颗粒的体积膨胀以及抑制锂枝晶的生长，因此，以该锂金属二次电池负极作为负极的锂金属二次电池具有良好的稳定性、循环性能、大电流快速充电能力以及安全性能。
本实施例提供的锂金属二次电池可以为本领域常规的任意的以金属锂作为负极的电池，包括但不限于锂金属空气电池以及锂硫电池。
以实施例三提供的锂金属二次电池负极制备锂金属二次电池的方法主要包括将实施例三提供的锂金属二次电池负极与锂金属二次电池的正极、隔膜、电解液以及外壳等部件进行组装、密封以及预充电等步骤，与本领域常规的制备锂金属二次电池的方法相同，在此不再赘述。
综上，本发明实施例利用泡沫电极基体具有孔道空腔这一特点，提供了一种以泡沫电极基体作为电极基体的锂金属电极。泡沫电极基体的孔道空腔能够有效限制分布在其中的金属锂颗粒的体积膨胀，并且有效抑制锂枝晶的生长，因此，以该锂金属电极作为负极的锂金属二次电池具有良好的稳定性能、循环性能、大电流快速充电能力以及安全性能。同时，本发明实施例提供的锂金属电极中金属锂颗粒表面还包覆有由锂离子良导体材料形成的保护层，在避免金属锂颗粒与外界气氛接触的同时，保证金属锂颗粒的反应活性，从而保证锂金属电极的性能。本发明实施例提供的锂金属电极适用于各类以金属锂作为的负极的锂金属二次电池，并且，本发明实施例提供的锂金属电极制备方法简单，成本较低，应用范围广泛。
上述本发明实施例序号仅仅为了描述，不代表实施例的优劣。
以上所述仅为本发明的较佳实施例，并不用以限制本发明，凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (20)

  1. 一种锂金属电极，其特征在于，包括：具有多个孔道空腔的泡沫电极基体，以及分布在所述泡沫电极基体的至少一个孔道空腔内的金属锂颗粒；
    所述泡沫电极基体的材料为泡沫金属材料或者碳泡沫材料。
  2. 根据权利要求1所述的锂金属电极，其特征在于，20％以上的所述多个孔道空腔内分布有金属锂颗粒。
  3. 根据权利要求1或2所述的锂金属电极，其特征在于，所述泡沫电极基体的孔道空腔的直径为100纳米～50微米。
  4. 根据权利要求1～3任一项所述的锂金属电极，其特征在于，所述锂金属电极还包括：包覆在所述金属锂颗粒表面的保护层；
    所述保护层的材料为锂离子良导体材料。
  5. 根据权利要求4所述的锂金属电极，其特征在于，所述保护层的材料选自Li2CO3、Li4SiO4、LiF、Li3PO3、TiO2、Li2TiO3、Li4Ti5O12、SiO2、SnO2、SiC、LiAlO2、Al2O3、NiS、CuS、FeS、MnS、Ag2S以及TiS2中的至少一种。
  6. 根据权利要求1～5任一项所述的锂金属电极，其特征在于，所述泡沫金属材料选自泡沫镍、泡沫铜、泡沫钛以及泡沫铁中的至少一种。
  7. 根据权利要求1～6任一项所述的锂金属电极，其特征在于，所述碳泡沫材料选自泡沫碳、泡沫碳纳米管以及泡沫石墨烯中的至少一种。
  8. 根据权利要求7所述的锂金属电极，其特征在于，所述泡沫石墨烯所用的石墨烯选自氧化石墨烯、还原石墨烯以及元素掺杂石墨烯中的至少一种；
    所述氧化石墨烯选自共价键功能化石墨烯以及非共价键功能化石墨烯中的至少一种；
    所述元素掺杂石墨烯中掺杂的元素选自氮、硫以及磷中的至少一种。
  9. 一种锂金属电极的制备方法，其特征在于，包括：
    准备具有多个孔道空腔的泡沫电极基体；
    在所述泡沫电极基体的至少一个孔道空腔内涂覆金属锂颗粒；
    所述泡沫电极基体的材料为泡沫金属材料或者碳泡沫材料。
  10. 根据权利要求9所述的制备方法，其特征在于，在20％以上的所述多个孔道空腔内涂覆金属锂颗粒。
  11. 根据权利要求9或10所述的制备方法，其特征在于，采用气相沉积法涂覆所述金属锂颗粒。
  12. 根据权利要求11所述的制备方法，其特征在于，采用真空蒸镀的方法涂覆所述金属锂颗粒；
    所述真空蒸镀的条件为：将所述泡沫电极基体固定在金属锂颗粒蒸发源的正上方，在1×10-2帕以下的压力下，用电流为50～500毫安、电压为3～12千伏的电子束轰击所述金属锂颗粒蒸发源，轰击时间为5～50分钟，所述泡沫电极基体与所述金属锂颗粒蒸发源的距离为30～150厘米。
  13. 根据权利要求9～12任一项所述的制备方法，其特征在于，所述制备方法还包括：
    在所述金属锂颗粒的表面涂覆保护层；
    所述保护层的材料为锂离子良导体材料。
  14. 根据权利要求13所述的制备方法，其特征在于，所述保护层的材料选自Li2CO3、Li4SiO4、LiF、Li3PO3、TiO2、Li2TiO3、Li4Ti5O12、SiO2、SnO2、SiC、LiAlO2、Al2O3、NiS、CuS、FeS、MnS、Ag2S以及TiS2中的至少一种。
  15. 根据权利要求13或14所述的制备方法，其特征在于，采用气相沉积法将所述保护层涂覆在所述金属锂颗粒表面。
  16. 一种锂金属二次电池负极，其特征在于，包括：至少一个权利要求1～8任一项所述的锂金属电极。
  17. 根据权利要求16所述的锂金属二次电池负极，其特征在于，当所述锂金属二次电池负极包括多个所述锂金属电极时，所述锂金属二次电池负极还包括：用于负载所述锂金属电极的基底。
  18. 根据权利要求17所述的锂金属二次电池负极，其特征在于，多个所述锂金属电极以阵列的形式设置在所述基底上。
  19. 一种锂金属二次电池，其特征在于，包括：外壳、电解液、正极、负极以及隔膜，其特征在于，所述负极为权利要求16～18任一项所述的锂金属二次电池负极。
  20. 根据权利要求19所述的锂金属二次电池，其特征在于，所述锂金属二次电池为锂金属空气电池或者锂硫电池。
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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3557676A1 (en) * 2018-04-18 2019-10-23 Brno University Of Technology Alkali and/or alkaline earth ion - monoclinic sulfur allotrope battery with self-supporting electrodes
CN114094111A (zh) * 2020-07-31 2022-02-25 比亚迪股份有限公司 一种补锂集流体、补锂集流体的制备方法、负极及锂离子电池
US20220123320A1 (en) * 2019-10-24 2022-04-21 Contemporary Amperex Technology Co., Limited Lithium metal composite electrode material, method for preparing the same, and electrode, battery, battery module, battery pack and apparatus comprising the same
EP3984085A4 (en) * 2019-06-16 2023-11-01 Applied Materials, Inc. PROTECTIVE SURFACES FOR ANODES OF LI-ION BATTERIES

Families Citing this family (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108155346B (zh) * 2017-11-23 2020-06-12 合肥国轩高科动力能源有限公司 一种锂离子电池正极片的制备方法
CN108134049B (zh) * 2017-12-19 2023-06-30 成都大超科技有限公司 负极层及其制备方法、锂电池电芯及锂电池
CN108172761B (zh) * 2017-12-30 2021-05-28 中南大学 一种用于锂二次电池的复合负极、及其制备和应用
CN108428860A (zh) * 2018-02-23 2018-08-21 天津大学 一种可加工成型的金属钠负极的制备方法
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CN108987796B (zh) * 2018-09-10 2020-09-01 江西克莱威纳米碳材料有限公司 一种柔性锂离子电池及其制备方法
CN109264705A (zh) * 2018-09-10 2019-01-25 上海新池能源科技有限公司 一种三维石墨烯薄膜的制备方法及三维石墨烯-铜复合电缆
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CN110518228B (zh) * 2019-09-17 2023-06-20 安徽大学 一种包埋无机纳米粒子的三维石墨烯碳纳米复合材料及其应用
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KR102892938B1 (ko) 2020-11-02 2025-11-27 주식회사 엘지에너지솔루션 리튬 금속 전지용 음극, 이의 제조방법 및 이를 포함하는 리튬 금속 전지
CN114639797B (zh) 2021-06-26 2023-12-29 宁德时代新能源科技股份有限公司 负极极片的处理方法、钠金属负极极片及制备装置
CN113451547B (zh) * 2021-06-30 2023-01-06 珠海冠宇电池股份有限公司 一种复合金属锂负极及包括该复合金属锂负极的锂离子电池
CN113451658A (zh) * 2021-07-08 2021-09-28 林健峯 一种三维电极结构的全固态锂离子电池及其制造方法
CN113594468B (zh) * 2021-07-29 2023-03-24 溧阳紫宸新材料科技有限公司 一种集流体及其制备方法和应用

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003257420A (ja) * 2002-03-06 2003-09-12 Japan Storage Battery Co Ltd 非水電解質二次電池
CN1645648A (zh) * 2003-08-20 2005-07-27 三星Sdi株式会社 保护锂金属电池负极的组合物及采用它的锂金属电池
CN101162772A (zh) * 2007-10-12 2008-04-16 哈尔滨工业大学 金属锂二次电池的泡沫锂负极及其制备方法
CN101399333A (zh) * 2007-10-12 2009-04-01 哈尔滨工业大学 金属锂二次电池的泡沫锂负极的制备方法

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100449765B1 (ko) * 2002-10-12 2004-09-22 삼성에스디아이 주식회사 리튬전지용 리튬메탈 애노드
KR100508945B1 (ko) * 2003-04-17 2005-08-17 삼성에스디아이 주식회사 리튬 전지용 음극, 그의 제조 방법 및 그를 포함하는 리튬전지
CN103947027B (zh) * 2011-10-13 2016-12-21 赛昂能源有限公司 电极结构及其制造方法
CN102683639B (zh) * 2012-06-12 2016-03-23 宁德新能源科技有限公司 一种锂离子电池阳极片及使用该阳极片的锂离子电池
DE102013226064A1 (de) * 2013-12-16 2015-06-18 Robert Bosch Gmbh Verfahren zur Herstellung einer Funktionsschicht für eine Lithium-Zelle
CN104291324A (zh) * 2014-09-09 2015-01-21 上海纳米技术及应用国家工程研究中心有限公司 一种石墨烯泡沫的制备方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003257420A (ja) * 2002-03-06 2003-09-12 Japan Storage Battery Co Ltd 非水電解質二次電池
CN1645648A (zh) * 2003-08-20 2005-07-27 三星Sdi株式会社 保护锂金属电池负极的组合物及采用它的锂金属电池
CN101162772A (zh) * 2007-10-12 2008-04-16 哈尔滨工业大学 金属锂二次电池的泡沫锂负极及其制备方法
CN101399333A (zh) * 2007-10-12 2009-04-01 哈尔滨工业大学 金属锂二次电池的泡沫锂负极的制备方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DING, FEI: "Study on Lithium Metal Anode Material of High Specific Energy Lithium Secondary Battery", SCIENCE-ENGINEERING (B), CHINESE SELECTED DOCTORAL DISSERTATIONS AND MASTER'S THESES FULL-TEXT DATABASES, no. 11, 15 November 2006 (2006-11-15), pages 104 *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3557676A1 (en) * 2018-04-18 2019-10-23 Brno University Of Technology Alkali and/or alkaline earth ion - monoclinic sulfur allotrope battery with self-supporting electrodes
WO2019201876A1 (en) * 2018-04-18 2019-10-24 Brno University of Technology Alkali and/or alkaline earth ion- sulfur battery
US11824191B2 (en) 2018-04-18 2023-11-21 Brno University of Technology Alkali and/or alkaline earth ion-sulfur battery
EP3984085A4 (en) * 2019-06-16 2023-11-01 Applied Materials, Inc. PROTECTIVE SURFACES FOR ANODES OF LI-ION BATTERIES
US12051810B2 (en) 2019-06-16 2024-07-30 Applied Materials, Inc. Protection interfaces for Li-ion battery anodes
US20220123320A1 (en) * 2019-10-24 2022-04-21 Contemporary Amperex Technology Co., Limited Lithium metal composite electrode material, method for preparing the same, and electrode, battery, battery module, battery pack and apparatus comprising the same
US11929509B2 (en) * 2019-10-24 2024-03-12 Contemporary Amperex Technology Co., Limited Metal lithium metal, supporting framework, and inorganic lithium compound, method for preparing the same, and electrode, battery, battery module, battery pack and apparatus comprising the same
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CN114094111B (zh) * 2020-07-31 2024-01-09 比亚迪股份有限公司 一种补锂集流体、补锂集流体的制备方法、负极及锂离子电池

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