WO2022142639A1 - 负极集流体及其制备方法和锂金属电池 - Google Patents

负极集流体及其制备方法和锂金属电池 Download PDF

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WO2022142639A1
WO2022142639A1 PCT/CN2021/126301 CN2021126301W WO2022142639A1 WO 2022142639 A1 WO2022142639 A1 WO 2022142639A1 CN 2021126301 W CN2021126301 W CN 2021126301W WO 2022142639 A1 WO2022142639 A1 WO 2022142639A1
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current collector
lithium
negative electrode
electrode current
layer
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PCT/CN2021/126301
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English (en)
French (fr)
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夏圣安
王平华
雷丹
杨俊峰
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华为技术有限公司
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Priority claimed from CN202011620667.3A external-priority patent/CN114695897B/zh
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP21913384.0A priority Critical patent/EP4258390A1/en
Publication of WO2022142639A1 publication Critical patent/WO2022142639A1/zh
Priority to US18/345,458 priority patent/US20230344020A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/70—Carriers or collectors characterised by shape or form
    • 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
    • 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
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • 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
    • H01M4/38—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
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • 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
    • H01M4/665—Composites
    • H01M4/667—Composites in the form of layers, e.g. 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
    • H01M4/70—Carriers or collectors characterised by shape or form
    • H01M4/76—Containers for holding the active material, e.g. tubes, capsules
    • H01M4/762—Porous or perforated metallic containers
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • 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 present application relates to the technical field of lithium batteries, in particular to a negative electrode current collector and a preparation method thereof, and a lithium metal battery using the negative electrode current collector.
  • the core components of lithium metal batteries mainly include positive electrodes, negative electrodes, electrolytes and separators.
  • metal foil is used as the current collector, and the positive electrode slurry containing the positive electrode active material and the binder is coated on the positive electrode current collector to form a positive electrode; the negative electrode slurry containing the negative electrode active material and the binder is coated on the negative electrode current collector. form a negative electrode.
  • the separator is located between the positive electrode and the negative electrode; the electrolyte is filled between the positive electrode and the separator, and between the negative electrode and the separator.
  • lithium ions are extracted from the lattice of the positive electrode material and deposited into the negative electrode after passing through the electrolyte; during discharging, lithium ions are extracted from the negative electrode and inserted into the lattice of the positive electrode material after passing through the electrolyte.
  • the cyclic deposition and detachment of lithium ions will cause the expansion and contraction of the cell system.
  • lithium dendrites will be formed, thereby reducing the Coulomb efficiency and causing safety problems (lithium dendrites). A short circuit after piercing the diaphragm poses a great safety risk).
  • a first aspect of the embodiments of the present application provides a negative electrode current collector for a lithium metal battery, including:
  • a porous current collector base wherein a plurality of channels are opened in the current collector base
  • lithium dissolving agent filled in the pores of the current collector matrix, and the lithium dissolving agent is a liquid or gel capable of dissolving lithium metal
  • a locking layer attached to the pore wall of the pore channel and located between the pore wall of the pore channel and the lithium dissolving agent, the locking layer is used to bind the lithium dissolving agent to the pore channel of the current collector matrix middle.
  • the negative electrode current collector can lock lithium ions in the pores of the porous current collector matrix and store them in the form of liquid or gel, which can reduce the volume expansion caused by lithium deposition on the one hand, and reduce lithium dendrites on the other hand.
  • the production greatly improves the safety of the battery.
  • the pore size of each channel is less than 100 ⁇ m; and the porosity of the current collector matrix is 20% to 85%.
  • the thickness of the current collector matrix is 5 ⁇ m ⁇ 150 ⁇ m.
  • the lithium-dissolving agent includes a small molecule compound having the ability to complex lithium ions or a polymer containing an aromatic hydrocarbon group, a small molecule solvent having the ability to complex lithium ions, and At least one of the polymers with the ability to complex lithium ions;
  • the small molecule solvents with the ability to complex lithium ions include ether solvents, amine small molecular solvents, thioethers, and alcohol small molecular solvents;
  • Polymers capable of complexing lithium ions include polyether polymers, polyamine polymers, and polythiol polymers.
  • the molar concentration of lithium in the lithium dissolving agent is 0.1M to 10M.
  • the aromatic hydrocarbon-based small molecule compounds include biphenyl, naphthalene, phenanthrene, anthracene, tetracene, and pyrene;
  • the polymers containing aromatic hydrocarbon groups include polymers containing aromatic groups of biphenyl, naphthalene, phenanthrene, anthracene, tetracene, and pyrene;
  • the ether solvents include ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, and tetrahydrofuran, tetrahydropyran , 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,4-dioxane, dimethyl ether, isopropyl ether, n-butyl ether , dibutyl ether, dimethoxymethane, dimethoxypropane, diglyme, 12-crown-4, 15-crown-5, 18-crown-6;
  • the amine-based small-molecule solvent includes ethylenediamine dimethylamine, ethylenediaminetetramethylamine, and diethylenediaminetetramethylamine;
  • the sulfide-based small-molecule solvent includes ethylenedithiol dimethyl sulfide, ethanedithiol diethyl sulfide, diethylenedithiol dimethyl sulfide, and tetraethylenedithiol dimethyl sulfide;
  • the alcoholic small-molecule solvent includes hexanol, heptanol, octanol, nonanol, and higher aliphatic alcohol, polyethylene glycol, and polyethylene glycol monomethyl ether;
  • the polyether polymers include polyethylene oxide and polypropylene oxide
  • the polyamine polymers include polyethylene diamine and polymethyl ethylene diamine;
  • the polythiol polymers include polyethylene dithiol and methyl polyethylene dithiol.
  • the material of the locking layer is selected from polyvinylidene fluoride, polyethylene oxide, polyacrylic acid, styrene butadiene rubber, carboxymethyl cellulose, polypyrrole, polyacrylonitrile, plant fiber, graphene , Graphene oxide, hard carbon and soft carbon, graphite, C 3 N 4 , rosin acid, rosin glyceride, polyvinyl alcohol, naphthalene sulfonic acid, benzamide, polyvinylidene fluoride, polyethyleneimine, tetratetrasilicate At least one of ethyl ester, polyvinyl chloride, hydrazine hydrobromide, trimethyl sulfoxide iodide, polytetrafluoroethylene, copolymer of polyvinylidene fluoride and hexafluoropropylene, polyurethane and polyacrylate.
  • the coating thickness of the locking layer is 50 nm ⁇ 10 ⁇ m.
  • an induction positioning layer is further provided on the hole wall of the channel, the induction positioning layer has the property of chemically reacting with lithium ions or lithiophilic, and the induction positioning layer is used to interact with the locking layer. Cooperate with each other to control the deposition position and deposition direction of lithium ions.
  • the material of the inductive positioning layer is selected from at least one of gold, silver, tin, zinc, magnesium, indium, copper oxide, zinc oxide, aluminum oxide, silicon, and germanium.
  • the current collector base includes a first surface and a second surface arranged oppositely; a plurality of channels are respectively opened from the first surface and the second surface, and each channel does not penetrate the The current collector matrix, and the pores opened on the first surface and the pores opened on the second surface are not connected to each other.
  • a second aspect of the embodiments of the present application provides a lithium metal battery, including the above-mentioned negative electrode current collector, a positive electrode, and a separator between the negative electrode current collector and the positive electrode, and the lithium metal battery directly uses the negative electrode current collector.
  • the fluid acts as the negative electrode.
  • a locking layer and/or an induced positioning layer are attached to the pore wall of the negative electrode current collector, and the pore is filled with a lithium-dissolving agent, which is stably existing in the pore by capillary adsorption; when charging, lithium ions enter the porous current collector. unit, and combined with the lithium dissolving agent to form lithium in liquid or gel state, the lithium in liquid or gel state can exist stably in the current collector unit, and the risk of lithium dendrites is reduced.
  • the lithium metal battery further includes a positive and negative electrode separator; the positive and negative electrode separators are located between the positive electrode and the negative electrode current collector; the positive and negative electrode separators are used to exchange lithium ions and prevent the lithium dissolving agent in the negative electrode current collector from reacting with the positive electrode.
  • the positive and negative electrode separators include a cation exchange membrane and a solid electrolyte; the thickness of the positive and negative electrode separators is 20 ⁇ m to 500 ⁇ m.
  • a third aspect of the embodiments of the present application provides a method for preparing a negative electrode current collector, including:
  • a lithium dissolving agent is filled in the pores, and the lithium dissolving agent is a liquid or gel capable of dissolving lithium metal, and the locking layer is used to bind the lithium dissolving agent in the pores of the current collector matrix .
  • the preparation method has a simple process and can bind the lithium dissolving agent in the pores of the current collector matrix through capillary action.
  • the step of forming a plurality of channels in the current collector matrix includes forming each channel with a pore diameter of less than 100 ⁇ m and the current collector matrix having a porosity of 20% to 85%.
  • the preparation method of the negative electrode current collector further includes the step of forming an induced positioning layer on the hole wall of the channel before forming the locking layer on the hole wall of the plurality of channels; the The induced positioning layer has the property of chemically reacting with lithium ions or being lithiophilic, and the induced positioning layer is used for cooperating with the locking layer to control the deposition position and deposition direction of the lithium ions.
  • the coating thickness of the induction positioning layer is 10 nm to 800 nm; the material of the induction positioning layer is selected from the group consisting of gold, silver, tin, zinc, magnesium, indium, copper oxide, zinc oxide, aluminum oxide, At least one of silicon and germanium.
  • FIG. 1 is a schematic structural diagram of an anode-free lithium metal battery according to an embodiment of the present application.
  • FIG. 2 is a schematic cross-sectional view of the negative electrode current collector of the first embodiment.
  • FIG 3 is a schematic top view of the negative electrode current collector of the first embodiment.
  • FIG. 4 is a schematic cross-sectional view of the negative electrode current collector of the second embodiment.
  • FIG. 5 is a schematic diagram of the capacity retention rates of the batteries of Examples 1 to 4 and the comparative example after 100 cycles of charge and discharge.
  • Anode-free lithium metal battery 100 Anode current collector 10 positive electrode 30 diaphragm 50 Positive current collector 31 Positive electrode slurry 33 channel 101 Current collector matrix 11 Lithium Solvent 13 lock layer 15 induced localization layer 17 first surface 102 second surface 104
  • a negative electrode-free lithium metal battery 100 includes a negative electrode current collector 10 , a positive electrode 30 , and a separator 50 located between the negative electrode current collector 10 and the positive electrode 30 .
  • the negative electrode-free lithium metal battery 100 directly uses the negative electrode current collector 10 as the negative electrode, and deposits metallic lithium on the surface of the negative electrode current collector 10 during charging.
  • the positive electrode 30 may include a positive electrode current collector 31 and a positive electrode slurry 33 provided on the positive electrode current collector 31 including a positive electrode active material, a binder, a conductive agent, and the like.
  • the positive electrode active material may be a lithium cobalt oxide material, a ternary material, a lithium-rich positive electrode material, or the like.
  • the negative-electrode-free lithium metal battery 100 may further include an electrolyte (not shown in the figure).
  • the positive electrode 30, the negative electrode and the separator 50 are porous structures, and the electrolyte can be filled in the positive electrode 30, the negative electrode and the separator. 50 in the pores.
  • the anode-free lithium metal battery 100 can also be an all-solid-state lithium metal battery.
  • the all-solid-state lithium metal battery has a solid-state electrolyte, and the solid-state electrolyte can be designed integrally with the positive electrode active material.
  • the positive electrode slurry and the solid electrolyte material are mixed and stirred in an appropriate ratio, coated on the surface of the positive electrode current collector, and vacuum baked to obtain a positive electrode integrating the positive electrode active material and the solid electrolyte.
  • lithium ions are cyclically deposited and detached, and the cell system undergoes changes in expansion and contraction; at the same time, due to the uneven deposition of lithium ions, lithium dendrites are easily formed, and lithium dendrites may pierce the separator and cause a short circuit. This leads to great security risks.
  • the present application provides a negative electrode current collector 10 for a negative electrode-free lithium metal battery 100, which can lock lithium ions in the pores of the porous negative electrode current collector 10 and store them in a liquid or gel state.
  • the negative electrode current collector 10 of the embodiment of the present application includes a current collector base 11 with a plurality of channels 101 , a lithium dissolving agent 13 and a locking layer 15 disposed in the channels 101 .
  • the lithium dissolving agent 13 is filled in the pores 101 of the current collector matrix 11 by capillary adsorption.
  • the lithium dissolving agent 13 is a liquid or gel capable of dissolving lithium metal.
  • the locking layer 15 is attached to the wall of the channel 101 and is located between the wall of the channel 101 and the lithium dissolving agent 13 , and the locking layer 15 can be used to improve the wetting of the lithium dissolving agent 13 . Wet performance, so that the lithium dissolving agent 13 is bound in the pores 101 of the current collector matrix 11 .
  • the current collector base 11 can be made of conductive materials such as copper, stainless steel, and alloys.
  • the current collector base 11 is in the shape of a thin layer, and the thickness may be 5 ⁇ m ⁇ 150 ⁇ m, preferably 10 ⁇ m ⁇ 50 ⁇ m. It should be noted that, unless otherwise specified, the parameter ranges in this application all include end values.
  • Conventional current collector substrates 11 may be processed using etching and/or electroplating processes to form channels 101 having an array of capillaries.
  • the porous current collector matrix 11 can not only collect current, but also serve as a liquid carrier for lithium ions.
  • the arrangement of the plurality of channels 101 may be regular arrangement, such as matrix arrangement, or irregular arrangement, such as foam type structure.
  • Each hole 101 may or may not penetrate the current collector base 11 .
  • the pore size of each channel 101 is less than 100 ⁇ m to ensure capillary effect.
  • the porosity of the current collector matrix 11 is 20% to 85%, so that a sufficient amount of the lithium solvent 13 can be accommodated in the current collector matrix 11 .
  • the lithium dissolving agent 13 is a liquid or gel capable of dissolving lithium metal, which can dissolve lithium metal through the synergistic effect of different organic solvents/polymers, and adsorb lithium ions in the pores 101 of the current collector matrix 11;
  • the lithium exists in the form of liquid or semi-liquid together with the lithium dissolving agent 13 to avoid the generation of lithium dendrites.
  • the contact angle between the lithium solvent 13 and the current collector substrate 11 is an acute angle.
  • the lithium dissolving agent 13 needs to dissolve lithium metal in the organic solvent/polymer in an inert atmosphere, the lithium metal and the organic solvent/polymer undergo a chemical reaction, the valence state of lithium changes from 0 to +1, and the formed lithium compound.
  • the inert atmosphere may be a nitrogen atmosphere or an argon atmosphere.
  • the lithium solvent 13 is selected from the group consisting of aromatic hydrocarbon small-molecule compounds with the ability to complex lithium ions or polymers containing aromatic hydrocarbon groups, and small molecular solvents with the ability to complex lithium ions (including ether solvents, amines, etc.). small molecule solvents, thioether-like small molecule solvents, alcohol-based small-molecule solvents), and polymers with the ability to complex lithium ions (including polyether-based polymers, polyamine-based polymers, and polythiol-based polymers) At least one of them, preferably a mixed solution of two or more kinds.
  • the molar concentration of lithium in the lithium solvent may be 0.1M-10M.
  • lithium concentration in the lithium solvent is too low, the loss of lithium ions in the process of charging and discharging cannot be completely supplemented; if the lithium concentration in the lithium solvent is too high, it is easy to cause excessive lithium supplementation, resulting in lithium precipitation on the positive electrode sheet , causing security risks.
  • aromatic hydrocarbon small molecule compounds include, but are not limited to, biphenyl, naphthalene, phenanthrene, anthracene, tetracene, pyrene, and the like.
  • the polymers containing aromatic hydrocarbon groups include, but are not limited to, polymers containing aromatic groups such as biphenyl, naphthalene, phenanthrene, anthracene, tetracene, and pyrene.
  • the ether solvents include but are not limited to ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, polyethylene glycol dimethyl ether and other chain ethers, and tetrahydrofuran, tetrahydropyran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,4-dioxane, dimethyl ether, iso Propyl ether, n-butyl ether, dibutyl ether, dimethoxymethane, dimethoxypropane, diglyme, 12-crown-4, 15-crown-5, 18-crown-6, etc. Cyclic ethers.
  • the amine-based small-molecule solvents include but are not limited to ethylenediamine dimethylamine, ethylenediaminetetramethylamine, diethylenediaminetetramethylamine, etc.;
  • the thioether-based small molecule solvents include but are not limited to ethylenedithiol dimethyl sulfide, ethanedithiol diethyl sulfide, diethylenedithiol dimethyl sulfide, tetraethylenedithiol dimethyl sulfide, etc. .
  • the alcohol-based small-molecule solvents include, but are not limited to, hexanol, heptanol, octanol, nonanol, and higher aliphatic alcohols, polyethylene glycol, polyethylene glycol monomethyl ether, and the like.
  • the polyether polymers include but are not limited to polyethylene oxide and polypropylene oxide.
  • the polyamine polymers include, but are not limited to, polyethylene diamine, polymethyl ethylene diamine, and the like.
  • the polythiol polymers include, but are not limited to, polyethylene dithiol, methyl polyethylene dithiol, and the like.
  • the solubility to metal lithium may be low, and the dissolution of lithium can be promoted by stirring and/or heating, but if the above-mentioned one is selected with other organic solvents or When two or more of the above-mentioned species are used in combination, a higher metal lithium dissolving ability will be produced.
  • the locking layer 15 is attached to the pore wall of the pore channel 101 of the current collector base 11, and can not only be closely combined with the current collector base 11, but also have an affinity with the lithium dissolving agent 13, so as to improve the dissolution of lithium Therefore, the lithium dissolving agent 13 is bound in the pores 101 of the current collector matrix 11 by capillary action.
  • the material of the locking layer 15 is selected from polyvinylidene fluoride (PVDF), polyethylene oxide (PEO), polyacrylic acid (PAA), styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), polypyrrole (PPy), Polyacrylonitrile (PAN), Vegetable Fiber, Graphene, Graphene Oxide, Hard Carbon, Soft Carbon, Graphite, C3N4 , Rosin Acid, Rosin Glycerides , Polyvinyl Alcohol, Naphthalene Sulfonic Acid, Benzene Formamide, polyvinylidene fluoride, polyethyleneimine, tetraethylorthosilicate, polyvinyl chloride, hydrazine hydrobromide, trimethyl sulfoxide iodide, polytetrafluoroethylene, polyvinylidene fluoride and hexafluoro At least one of propylene copolymer, polyurethane and polyacrylate.
  • the thickness of the locking layer 15 is 50 nm ⁇ 10 ⁇ m, preferably, the coating thickness is 500 nm ⁇ 5 ⁇ m.
  • An inductive positioning layer 17 may also be selectively disposed on the hole wall of the hole channel 101 .
  • the inductive positioning layer 17 and the locking layer 15 cooperate with each other to control the deposition position of lithium ions and induce the deposition direction of lithium ions, thereby ensuring that the separator has no risk of puncture.
  • the coating thickness of the induced positioning layer 17 is 10 nm ⁇ 800 nm.
  • the inductive positioning layer 17 can chemically react with lithium ions or have a great lithiophilic property, so as to induce lithium ions to enter the inside of the pores 101 of the current collector base 11 for deposition.
  • the material of the induced positioning layer 17 can be selected from lithiophilic materials such as gold, silver, tin, zinc, magnesium, indium, copper oxide, zinc oxide, aluminum oxide, silicon, germanium and the like.
  • the inductive positioning layer 17 is directly attached to the hole wall of the channel 101 at least partially, and the locking layer 15 may be directly attached to the hole wall of the channel 101 partially and directly cover the inductive positioning layer 17 locally.
  • the induction positioning layer 17 is a solid layer.
  • the locking layer 15 is PEO, the locking layer 15 is a liquid layer.
  • the negative electrode current collector 10 of the present application can also be configured as a structure with double-sided openings, as shown in FIG. 4 .
  • the current collector base 11 of the negative electrode current collector 10 includes a first surface 102 and a second surface 104 that are oppositely arranged; a plurality of channels 101 are respectively opened from the first surface 102 and the second surface 104, and the channels opened on the first surface 102 101 and the channel 101 opened on the second surface 104 are not connected to each other.
  • Each hole 101 does not penetrate through the current collector base 11 , that is, each hole 101 is a blind hole.
  • each hole 101 is about half of the thickness of the current collector base 11 .
  • each channel 101 is also provided with the above-mentioned lithium solvent 13 and the above-mentioned locking layer 15 , as well as the selective induction and positioning layer 17 , which will not be repeated here.
  • the negative electrode-free lithium metal battery 100 may optionally include a positive and negative electrode separator (not shown).
  • the positive and negative electrode separators are located between the positive electrode and the negative electrode current collector.
  • the positive and negative electrode separators can exchange lithium ions, thereby preventing the lithium dissolving agent in the current collector matrix from reacting with the positive electrode side.
  • the positive and negative electrode separators include cation exchange membrane, solid electrolyte and other materials.
  • the thickness of the positive and negative electrode separators is 20 ⁇ m ⁇ 500 ⁇ m.
  • the present application also provides a method for preparing the negative electrode current collector, comprising the following steps:
  • a lithium dissolving agent is filled in the pores.
  • the preparation method has a simple process and can bind the lithium dissolving agent in the pores of the current collector matrix through capillary action.
  • the induction positioning layer is a solid layer, and when the locking layer is selected as a liquid layer, an induction positioning layer needs to be formed on the hole wall of the channel first, and then the locking layer is formed; and the locking layer is not The induction positioning layer is completely covered, and the induction positioning layer is at least partially exposed relative to the locking layer.
  • the step of providing a current collector base includes providing a thin layer current collector base that can be made of conductive materials such as copper, stainless steel, and alloys.
  • the thickness of the current collector base is 5 ⁇ m to 150 ⁇ m, preferably 10 ⁇ m to 50 ⁇ m.
  • the channels with a capillary array may be formed by laser drilling or etching.
  • the arrangement of the plurality of channels can be regular arrangement, such as matrix arrangement, or irregular arrangement, such as foam type structure.
  • Each channel may or may not penetrate the current collector matrix.
  • the pore size of each channel is less than 100 ⁇ m.
  • the porosity of the current collector matrix is 20% to 85%.
  • the lithium dissolving agent is a liquid or gel capable of dissolving lithium metal.
  • the lithium dissolving agent needs to dissolve lithium metal in an organic solution in an inert atmosphere to form a lithium compound.
  • the lithium solvent is selected from the group consisting of aromatic hydrocarbon small-molecule compounds with the ability to complex lithium ions or polymers containing aromatic hydrocarbon groups, and small molecular solvents with the ability to complex lithium ions (including ether solvents, amines, etc.). Small molecule solvents, thioether small molecule solvents, alcohol small molecule solvents), and polymers with the ability to complex lithium ions (including polyether polymers, polyamine polymers, and polythiol polymers) At least one, preferably two or more kinds of mixed solutions are prepared.
  • the molar concentration of lithium in the lithium solvent may be 0.1-10M. Dissolving an appropriate amount of lithium metal in the above organic mixed solution can promote the dissolution process of metal lithium by stirring or heating, thereby obtaining a lithium dissolving agent.
  • the concentration of lithium in the lithium solvent is 0.1M-10M.
  • the step of filling the lithium-dissolving agent in the pores includes: immersing the porous current collector matrix formed with the locking layer in the lithium-solvent agent for 5 minutes to 5 hours, so that the lithium-solvent agent completely occupies the pores of the current collector matrix; After taking out, the lithium solvent substance on the surface of the porous current collector substrate is removed. It can be understood that the method of filling the lithium solvent in the pores is not limited to this.
  • the present application also provides a method for preparing an anode-free lithium metal battery using the above-mentioned anode current collector, which specifically includes the following steps.
  • the above-mentioned negative electrode current collector is prepared to replace the traditional negative electrode plate.
  • the positive electrode can use a traditional positive electrode plate, for example, a positive electrode slurry is coated on the surface of the positive electrode current collector.
  • the positive electrode slurry includes a positive electrode active material, a binder, a conductive agent, and the like, and the positive electrode active material includes a lithium cobalt oxide material, a ternary material, a lithium-rich positive electrode material, and the like.
  • the above-mentioned porous current collector unit, separator, and positive pole pieces are wound or laminated to form a bare cell, and an electrolyte solution is injected into the bare cell, and the liquid is injected and then packaged, thereby preparing a negative electrode-free lithium metal battery.
  • the electrolyte is composed of a solvent and a metal salt
  • the solvent includes one or more of carbonate-based solvents, ether-based solvents, and carboxylate-based solvents.
  • the carbonate-based solvent includes cyclic carbonate or chain carbonate
  • the cyclic carbonate may specifically be ethylene carbonate (EC), propylene carbonate (PC), ⁇ -butyrolactone (GBL) , one or more of butylene carbonate (BC), fluoroethylene carbonate (FEC), vinylene carbonate (VC);
  • the chain carbonate can be specifically dimethyl carbonate (DMC), carbonic acid One or more of ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and dipropyl carbonate (DPC).
  • the ether solvent includes cyclic ether or chain ether
  • the cyclic ether can be 1,3-dioxolane (DOL), 1,4-dioxoxane (DX), crown ether, tetrahydrofuran specifically One or more of (THF), 2-methyltetrahydrofuran (2-CH3-THF), 2-trifluoromethyltetrahydrofuran (2-CF3-THF);
  • the chain ether can be specifically dimethoxy One or more of methyl methane (DMM), 1,2-dimethoxyethane (DME), diglyme (TEGDME).
  • the carboxylate solvent can be specifically one of methyl acetate (MA), ethyl acetate (EA), propyl acetate (EP), butyl acetate, propyl propionate (PP), and butyl propionate. one or more.
  • the metal salt anions include, but are not limited to, hexafluorophosphate anion (PF 6 ⁇ ), hexafluoroarsenate anion (AsF 6 ⁇ ), perchlorate anion (ClO 4 ⁇ ), tetrafluoroborate anion (BF 4 ).
  • the use of the above negative current collectors can be extended to all-solid-state lithium metal batteries.
  • the positive electrode side adopts the integrated design of the positive electrode active material and the solid electrolyte.
  • the positive electrode active material, the conductive agent, the binder and the solid electrolyte material are mixed in an appropriate ratio and stirred to prepare a slurry.
  • the slurry is uniformly coated on the surface of the positive electrode current collector, and vacuum-baked to obtain an integrated positive electrode electrode piece of positive electrode active material and solid electrolyte;
  • a negative electrode-free all-solid-state lithium metal battery is made by lamination process.
  • the inorganic solid electrolytes include oxide solid electrolytes or sulfide solid electrolytes common in the art.
  • the oxide solid electrolytes are perovskite solid electrolytes, sodium fast ion conductor solid electrolytes (ie NASICON solid electrolytes), Lithium fast ion conductor type solid electrolyte (ie LISICON type solid electrolyte), garnet type solid electrolyte, or glassy oxide solid electrolyte, etc.
  • the sulfide solid electrolyte is thio-lithium fast ion conductor type (ie thio-LISICON type) solid electrolyte), or a glassy sulfide solid electrolyte, or a composite of the above inorganic solid electrolytes.
  • a preparation of a negative electrode-free lithium metal battery comprising:
  • the substances and concentrations contained are: methanesulfonic acid 200g/L, tin methanesulfonate 200g/L, thiourea 70g/L, sodium hypophosphite 10g/L, ethylenediamine Tetraacetic acid (EDTA) 2g/L, ascorbic acid 2g/L.
  • the current collector matrix of the three-dimensional porous array was immersed in the above-mentioned electroless tin plating solution, and allowed to stand for 5 minutes. Afterwards, the three-dimensional porous array current collector substrate was vertically pulled out of the solution, and the aqueous solution on the surface of the current collector substrate was drained.
  • the current collector was placed at 90 °C for 30 min. After completion, the salt in the current collector pores was removed by washing with water and the moisture in the pores of the three-dimensional porous array current collector was removed by drying to obtain Sn coated on the pores of the porous current collector matrix. induced localization layer.
  • metal lithium and biphenyl are dissolved in a ethylene glycol dimethyl ether solution in a mass ratio of 1:22 (molar ratio is 1:1) to form a uniform solution ( Lithium solvent), the concentration of biphenyl is 1M.
  • the current collector matrix with the inner pore walls forming a three-dimensional porous array coated with a Sn layer and a PEO layer was immersed in the above solution and allowed to stand for 5 min.
  • the current collector substrate of the three-dimensional porous array is vertically pulled out of the solution, and the lithium-dissolving solution on the surface of the current collector is drained and removed to obtain a three-dimensional porous array current collector substrate coated with an induced positioning layer, a locking layer and a lithium-dissolving agent, that is, Negative current collector.
  • a preparation of a negative electrode-free lithium metal battery comprising:
  • the following electroless tin plating solution is configured, and the substances and concentrations contained are: methanesulfonic acid 200g/L, tin methanesulfonate 200g/L, thiourea 70g/L, sodium hypophosphite 10g/L, EDTA 2g /L, ascorbic acid 2g/L.
  • the current collector matrix of the three-dimensional porous array was immersed in the above solution and allowed to stand for 5 min. Then, the current collector matrix of the three-dimensional porous array is vertically pulled out of the solution, and the aqueous solution on the surface of the current collector matrix is drained. After that, the current collector was placed at 90 °C for 30 min of reaction.
  • the salt in the pores of the current collector matrix was removed by washing with water, and the moisture in the pores of the current collector matrix of the three-dimensional porous array was dried to remove the water to obtain the pores coated on the porous current collector matrix. Sn-induced localization layer of the wall.
  • metal lithium and biphenyl are dissolved in a ethylene glycol dimethyl ether solution according to a mass ratio of 1:22 (molar ratio is 1:1) to form a uniform solution (lithium dissolving agent), The concentration of biphenyl is 1M.
  • the current collector matrix of the three-dimensional porous array with internal channels coated with Sn layer and PEO layer was immersed in the above solution and left for 5 min.
  • the current collector matrix of the three-dimensional porous array is vertically pulled out of the solution, and the lithium-dissolving solution on the surface of the current-collector substrate is drained and removed to obtain a three-dimensional porous array with an induced positioning layer, a locking layer and a lithium-dissolving agent. collector.
  • Li 7 La 3 Zr 2 O 12 (LLZO) ceramic sheets with a thickness of 50 ⁇ m were used as positive and negative electrode separators.
  • ( 6 ) assemble the above-mentioned negative electrode current collector, lithium cobalt oxide positive electrode and positive and negative electrode separator into a button cell, and drip 50 ⁇ L of LiPF 6 electrolyte with a concentration of 1.0 mol/L from the positive end (DMC, The weight ratio of EMC and EC is 1:1:1) infiltrating the positive pole piece.
  • a preparation of a negative electrode-free lithium metal battery comprising:
  • the anode current collector is processed into a current collector matrix of a three-dimensional porous array by a laser drilling process.
  • the following electroless tin plating solution is configured, and the substances and concentrations contained are: methanesulfonic acid 200g/L, tin methanesulfonate 200g/L, thiourea 70g/L, sodium hypophosphite 10g/L, EDTA 2g /L, ascorbic acid 2g/L.
  • the three-dimensional porous array current collector was immersed in the above solution and allowed to stand for 5 min. Then, the current collector matrix of the three-dimensional porous array is vertically pulled out of the solution, and the aqueous solution on the surface of the current collector matrix is drained. Then, the current collector substrate was placed at 90 °C for 30 min.
  • the salt in the pores of the current collector substrate was removed by washing with water, and the moisture in the pores of the current collector substrate of the three-dimensional porous array was removed by drying to obtain a porous current collector substrate. Sn-induced localization layer on the pore wall of the channel.
  • metal lithium and biphenyl are dissolved in a ethylene glycol dimethyl ether solution according to a mass ratio of 1:22 (molar ratio is 1:1) to form a uniform solution (lithium dissolving agent), The concentration of biphenyl is 1M.
  • the current collector matrix of the three-dimensional porous array with internal channels coated with Sn layer and PEO layer was immersed in the above solution and left for 5 min.
  • the current collector matrix of the three-dimensional porous array is vertically pulled out of the solution, and the lithium-dissolving solution on the surface of the current-collector substrate is drained and removed to obtain a three-dimensional porous array current collector with an induced positioning layer, a locking layer and a lithium-dissolving agent, that is, the negative electrode collector. fluid.
  • the lithium cobalt oxide positive electrode of the above-mentioned preparation, the lithium cobalt oxide positive electrode protected by the solid electrolyte, and the positive and negative electrode separators are assembled into a button cell, and 50 ⁇ L of the LiPF 6 electrolyte (the LiPF 6 electrolytic solution that is 1.0 mol/L) is added dropwise from the positive electrode end.
  • the weight ratio of DMC, EMC, and EC in the solution is 1:1:1) to infiltrate the positive electrode sheet.
  • a preparation of a negative electrode-free lithium metal battery comprising:
  • the anode current collector is processed into a current collector matrix of a three-dimensional porous array by a laser drilling process.
  • the following electroless tin plating solution is configured, and the substances and concentrations contained are: methanesulfonic acid 200g/L, tin methanesulfonate 200g/L, thiourea 70g/L, sodium hypophosphite 10g/L, EDTA 2g /L, ascorbic acid 2g/L.
  • the three-dimensional porous array current collector was immersed in the above solution and allowed to stand for 5 min. Then, the current collector matrix of the three-dimensional porous array is vertically pulled out of the solution, and the aqueous solution on the surface of the current collector matrix is drained. Then, the current collector matrix was placed at 90 °C for 30 min.
  • the salt in the pores of the current collector matrix was removed by washing with water, and the moisture in the pores of the current collector matrix of the three-dimensional porous array was removed by drying to obtain a porous current collector matrix.
  • the Sn-induced localization layer of the pore wall was removed by washing with water, and the moisture in the pores of the current collector matrix of the three-dimensional porous array was removed by drying to obtain a porous current collector matrix.
  • the liquid negative electrode was transferred into the glove box again and placed on a heating plate, and the temperature of the heating plate was set to 70° C., so that the THF was completely volatilized.
  • the three-dimensional porous array current collector whose inner channel is coated with Sn layer and PEO layer is placed on a glass plate, and the prepared liquid negative electrode is evenly coated in the channel of the current collector using a roller, and 50 ⁇ m LLZO
  • the ceramic sheet is attached to the current collector coated with the liquid negative electrode, and the excess liquid negative electrode at the edge is removed to obtain a three-dimensional porous array current collector with an induced positioning layer, a locking layer and a lithium dissolving agent, which is encapsulated and protected by an all-solid electrolyte, that is, the negative electrode collector. fluid.
  • LiCoO 2 /Li battery assembly Lithium metal foil, lithium cobalt oxide positive electrode and Celgard separator were assembled into a button battery, and 50 ⁇ L of LiPF6 electrolyte with a concentration of 1.0 mol/L was added dropwise (DMC, EMC, EC in this LiPF6 electrolyte The weight ratio is 1:1:1).
  • the batteries assembled in Examples 1 to 4 and the comparative example were respectively charged and discharged according to the 0.1C/0.2C charge and discharge system.
  • the battery voltage range of lithium metal was 3.0 to 4.5V.
  • the test results are shown in Table 1 and Figure 1. 5 shown.
  • a locking layer and/or an induced positioning layer are attached to the walls of the pores of the porous current collector matrix, and the pores are filled with a lithium-dissolving agent, which exists stably in the pores by capillary adsorption; during charging, lithium ions enter the porous
  • the current collector unit is combined with a lithium dissolving agent to form liquid metal lithium, and the liquid metal lithium can exist stably in the current collector unit and reduce the risk of lithium dendrites.

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Abstract

本申请提供一种锂金属电池的负极集流体，包括：开设有多个孔道的集流体基体、填充于所述集流体基体的孔道中的溶锂剂、附着于所述孔道的孔壁上且位于所述孔道的孔壁与所述溶锂剂之间的锁定层。所述溶锂剂为具备溶解锂金属能力的液体或凝胶体。所述锁定层用于将所述溶锂剂束缚在所述集流体基体的孔道中。本申请还提供该种应用该负极集流体的锂金属电池和该负极集流体的制备方法。所述负极集流体将锂离子锁定在集流体基体的孔道中并以液体或凝胶体的形式储存，可减少锂沉积所带来的体积膨胀，同时减少锂枝晶的产生，极大地提高电池的安全性。

Description

负极集流体及其制备方法和锂金属电池
相关申请的交叉引用
本申请要求在2020年12月31日提交中国专利局、申请号为202011620667.3、申请名称为“负极集流体及其制备方法和锂金属电池”的中国专利的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及锂电池技术领域，具体涉及一种负极集流体及其制备方法，以及应用该负极集流体的锂金属电池。
背景技术
锂金属电池的核心部件主要包括正极、负极、电解液和隔膜。通常采用金属箔作为集流体，将包含正极活性材料和粘合剂的正极浆料涂覆在正极集流体上形成正极；将包含负极活性材料和粘合剂的负极浆料涂覆在负极集流体上形成负极。隔膜位于正极与负极之间；电解液填充在正极与隔膜之间、负极与隔膜之间。充电时，锂离子从正极材料的晶格中脱出，经过电解液后沉积到负极中；放电时锂离子从负极中脱出，经过电解液后插入到正极材料的晶格中。在充放电过程中，锂离子的循环沉积和脱离，会造成电芯体系的膨胀收缩变化，同时由于锂离子的沉积不均匀会形成锂枝晶，从而降低库伦效率和引起安全问题(锂枝晶刺穿隔膜后会引起短路带来极大的安全风险)。
发明内容
本申请实施例第一方面提供了一种锂金属电池的负极集流体，包括：
多孔的集流体基体，所述集流体基体中开设有多个孔道；
溶锂剂，填充于所述集流体基体的孔道中，所述溶锂剂为具备溶解锂金属能力的液体或凝胶体；
锁定层，附着于所述孔道的孔壁上且位于所述孔道的孔壁与所述溶锂剂之间，所述锁定层用于将所述溶锂剂束缚在所述集流体基体的孔道中。
所述负极集流体可将锂离子锁定在多孔的集流体基体的孔道中并以液体或凝胶体的形式储存，一方面可以减少锂沉积所带来的体积膨胀，另一方面减少锂枝晶的产生，极大地提高电池的安全性。
本申请实施方式中，每一个孔道的孔径小于100μm；且所述集流体基体的孔隙率为20％～85％。
本申请实施方式中，所述集流体基体的厚度为5μm～150μm。
本申请实施方式中，所述溶锂剂包括选自具备络合锂离子能力的芳香烃类小分子化合物或含芳香烃类基团的聚合物、具备络合锂离子能力的小分子溶剂、以及具备络合锂离子能力的聚合物中的至少一种；所述具备络合锂离子能力的小分子溶剂包括醚类溶剂、胺类小分子溶剂、硫醚、醇类小分子溶剂；所述具备络合锂离子能力的聚合物包括聚醚类聚合物、聚胺类聚合物、聚硫醇类聚合物。
本申请实施方式中，所述溶锂剂中锂的体积摩尔浓度为0.1M～10M。
本申请实施方式中，所述芳香烃类小分子化合物包括联苯、萘、菲、蒽、并四苯、芘；
所述含芳香烃类基团的聚合物包括含有联苯、萘、菲、蒽、并四苯、芘的芳香基团的聚合物；
所述醚类溶剂包括乙二醇二甲醚、乙二醇二乙醚、二乙二醇二甲醚、四乙二醇二甲醚、聚乙二醇二甲醚，以及四氢呋喃、四氢吡喃、2-甲基四氢呋喃、1,3-二氧戊环、4-甲基-1,3二氧戊环、1,4-二氧六环、二甲醚、异丙醚、正丁基醚、二丁醚、二甲氧甲烷、二甲氧丙烷、二甘醇二甲醚、12-冠醚-4、15-冠醚-5、18-冠醚-6；
所述胺类小分子溶剂包括乙二胺二甲胺、乙二胺四甲胺、二乙二胺四甲胺；
所述硫醚类小分子溶剂包括乙二硫醇二甲硫醚、乙二硫醇二乙硫醚、二乙二硫醇二甲硫醚、四乙二硫醇二甲硫醚；
所述醇类小分子溶剂包括己醇、庚醇、辛醇、壬醇以及高级脂肪醇、聚乙二醇、聚乙二醇单甲醚；
所述聚醚类聚合物包括聚环氧乙烷、聚环氧丙烷；
所述聚胺类聚合物包括聚乙二胺、聚甲基乙二胺；
所述聚硫醇类聚合物包括聚乙二硫醇、甲基聚乙二硫醇。
本申请实施方式中，所述锁定层的材料选自聚偏氟乙烯、聚环氧乙烷、聚丙烯酸、丁苯橡胶、羧甲基纤维素、聚吡咯、聚丙烯腈、植物纤维、石墨烯、氧化石墨烯、硬碳软碳、石墨、C 3N 4、松香酸、松香甘油酯、聚乙烯醇、萘磺酸、苯甲酰胺、聚偏氟乙烯、聚乙烯亚胺、正硅酸四乙酯、聚氯乙烯、氢溴酸肼、三甲基碘化亚砜、聚四氟乙烯、聚偏二氟乙烯与六氟丙烯的共聚物、聚氨酯、聚丙烯酸酯中的至少一种。
本申请实施方式中，该锁定层的涂覆厚度为50nm～10μm。
本申请实施方式中，所述孔道的孔壁上还设置有诱导定位层，所述诱导定位层具备与锂离子发生化学反应或者亲锂的性质，所述诱导定位层用以与所述锁定层相互配合控制锂离子的沉积位置和沉积方向。
本申请实施方式中，所述诱导定位层的材料选自金、银、锡、锌、镁、铟、氧化铜、氧化锌、氧化铝、硅、锗中的至少一种。
本申请实施方式中，所述集流体基体包括相对设置的第一表面和第二表面；从所述第一表面和所述第二表面分别开设有多个孔道，每一个孔道均不贯穿所述集流体基体，且所述第一表面开设的孔道与所述第二表面开设的孔道是相互不连通的。
本申请实施例第二方面提供了一种锂金属电池，包括上述的负极集流体、正极、位于所述负极集流体和所述正极之间的隔膜，所述锂金属电池直接使用所述负极集流体作为负极。
所述负极集流体的孔道壁附着有锁定层和/或诱导定位层，孔道内填充溶锂剂，溶锂剂依靠毛细管吸附作用在孔道内稳定存在；充电时，锂离子进入该多孔的集流体单元，并与溶锂剂结合，形成液态或凝胶态的锂，该液态或凝胶态的锂在该集流体单元中可稳定存在，且降低锂枝晶产生的风险。
本申请实施方式中，所述锂金属电池还包括正负极隔离层；所述正负极隔离层位于所述正极和所述负极集流体之间；所述正负极隔离层用以交换锂离子且防止所述负极集流体中的所述溶锂剂与所述正极发生反应。
本申请实施方式中，所述正负极隔离层包括阳离子交换膜、固态电解质；所述正负极隔 离层的厚度为20μm～500μm。
本申请实施例第三方面提供了一种负极集流体的制备方法，包括：
提供集流体基体；
在所述集流体基体中形成多个孔道；
在所述孔道的孔壁上形成锁定层；
在所述孔道内填充溶锂剂，所述溶锂剂为具备溶解锂金属能力的液体或凝胶体，所述锁定层用于将所述溶锂剂束缚在所述集流体基体的孔道中。
所述制备方法工艺简单，能够通过毛细作用将所述溶锂剂束缚在所述集流体基体的孔道中。
本申请实施方式中，在所述集流体基体中形成多个孔道的步骤包括形成每一个孔道的孔径小于100μm且所述集流体基体的孔隙率为20％～85％。
本申请实施方式中，所述负极集流体的制备方法还包括在所述多个孔道的孔壁上形成所述锁定层之前，在所述孔道的孔壁上形成诱导定位层的步骤；所述诱导定位层具备与锂离子发生化学反应或者亲锂的性质，所述诱导定位层用以与所述锁定层相互配合控制锂离子的沉积位置和沉积方向。
本申请实施方式中，所述诱导定位层的涂覆厚度为10nm～800nm；所述诱导定位层的材料选自金、银、锡、锌、镁、铟、氧化铜、氧化锌、氧化铝、硅、锗中的至少一种。
附图说明
图1是本申请实施例的无负极锂金属电池的结构示意图。
图2是第一实施例的负极集流体的剖面示意图。
图3是第一实施例的负极集流体的俯视示意图。
图4是第二实施例的负极集流体的剖面示意图。
图5是实施例1至4与对比例的电池充放电循环100圈后的容量保持率的示意图。
主要元件符号说明
无负极锂金属电池 100
负极集流体 10
正极 30
隔膜 50
正极集流体 31
正极浆料 33
孔道 101
集流体基体 11
溶锂剂 13
锁定层 15
诱导定位层 17
第一表面 102
第二表面 104
具体实施方式
下面结合本申请实施例中的附图对本申请实施例进行描述。
如图1所示，一种无负极锂金属电池100，包括负极集流体10、正极30、位于所述负极集流体10和所述正极30之间的隔膜50。所述无负极锂金属电池100直接使用负极集流体10作为负极，充电时在负极集流体10表面沉积金属锂，在放电过程中金属锂转变为锂离子回到正极，实现循环充放电。所述正极30可包括正极集流体31和设置在所述正极集流体31上的包含正极活性材料、粘合剂、导电剂等的正极浆料33。该正极活性材料可为钴酸锂材料、三元材料、富锂正极材料等。所述无负极锂金属电池100还可包括电解液(图未示)，通常正极30、负极以及隔膜50均为多孔的结构，所述电解液可填充在所述正极30、负极以及所述隔膜50的孔隙中。
可以理解的，所述无负极锂金属电池100也可为全固态锂金属电池。所述全固态锂金属电池具有固态电解质，固态电解质可与正极活性材料一体化设计。正极集流体31表面形成有包含正极活性材料、粘合剂、导电剂等的正极浆料和固态电解质。正极浆料与固态电解质材料按照合适的比例进行混合并搅拌，涂覆在正极集流体表面，并真空烘烤，制得正极活性物质与固态电解质一体化的正极。
然而，随着电池的使用时间增长，锂离子循环沉积和脱离，电芯体系发生膨胀收缩变化；同时由于锂离子的沉积不均匀易形成锂枝晶，锂枝晶可能刺穿隔膜从而引起短路，进而带来极大的安全风险。
本申请提供一种用于无负极锂金属电池100的负极集流体10，其可将锂离子锁定在多孔的负极集流体10的孔道中并以液态或凝胶态的形式储存，一方面可以减少锂沉积所带来的体积膨胀，同时减少锂枝晶的产生，极大地提高电池的安全性。
如图2和图3所示，本申请实施例的负极集流体10包括开设有多个孔道101的集流体基体11以及设置在所述孔道101中的溶锂剂13和锁定层15。所述溶锂剂13依靠毛细管吸附作用填充于所述集流体基体11的孔道101中。所述溶锂剂13为具备溶解锂金属能力的液体或凝胶体。所述锁定层15附着于所述孔道101的孔壁上且位于所述孔道101的孔壁与所述溶锂剂13之间，所述锁定层15可用于改善所述溶锂剂13的润湿性能，从而将所述溶锂剂13束缚在所述集流体基体11的孔道101中。
所述集流体基体11的材质可为铜、不锈钢、合金等导电材料。所述集流体基体11为一薄层状，厚度可为5μm～150μm，优选为10μm～50μm。需要说明的是，如无特别说明，本申请中的参数范围均包括端值。
可采用刻蚀和\或电镀工艺对传统的集流体基体11进行加工，以形成具有毛细管阵列的孔道101。所述多孔的集流体基体11不仅可汇集电流，还可作为锂离子的液态载体。所述多个孔道101的排布可为规律排布，例如矩阵排布，也可为不规律排布，如可为泡沫类型结构。每一个孔道101可以贯穿所述集流体基体11，也可以不贯穿集流体基体11。每一个孔道101的孔径小于100μm，以保证产生毛细管效应。所述集流体基体11的孔隙率为20％～85％，以使集流体基体11中能够容纳足够量的溶锂剂13。
所述溶锂剂13为具有溶解锂金属能力的液体或凝胶体，可通过不同有机溶剂/聚合物的协同作用溶解金属锂，将锂离子吸附在集流体基体11的孔道101内；且吸附的锂与溶锂剂13一起以液态或半液态的形式存在，避免锂枝晶的产生。所述溶锂剂13与集流体基体11的接触角为锐角。
所述溶锂剂13需在惰性气氛中将锂金属溶于有机溶剂/聚合物中，锂金属与有机溶剂/聚合物发生化学反应，锂的价态从0变成+1，形成的锂的化合物。所述惰性气氛可为氮气气氛或氩气气氛。
通过把集流体基体11加工具有毛细管阵列的孔道101，利用毛细原理把类固态或液态的锂离子吸附存储在毛细管的孔道101中，从而限制锂的存在范围，消除锂枝晶的隐患，进而提高锂金属电池的安全性。
所述溶锂剂13包括选自具备络合锂离子能力的芳香烃类小分子化合物或含芳香烃类基团的聚合物、具备络合锂离子能力的小分子溶剂(包括醚类溶剂、胺类小分子溶剂、硫醚小分子溶剂、醇类小分子溶剂)、以及具备络合锂离子能力的聚合物(包括聚醚类聚合物、聚胺类聚合物、聚硫醇类聚合物)中的至少一种，优选为两种或两种以上的种类配置而成的混合溶液。所述溶锂剂中锂的体积摩尔浓度可为0.1M～10M。若所述溶锂剂中锂的浓度太低，不能完全补充充放电过程中锂离子的损耗；若所述溶锂剂中锂的浓度太高，很容易造成补锂过量，导致正极片析锂，引发安全隐患。
所述芳香烃类小分子化合物包括但不限于联苯、萘、菲、蒽、并四苯、芘等。
所述含芳香烃类基团的聚合物包括但不限于含有联苯、萘、菲、蒽、并四苯、芘等芳香基团的聚合物。
所述醚类溶剂包括但不限于乙二醇二甲醚、乙二醇二乙醚、二乙二醇二甲醚、四乙二醇二甲醚、聚乙二醇二甲醚等链状醚，以及四氢呋喃、四氢吡喃、2-甲基四氢呋喃、1,3-二氧戊环、4-甲基-1,3二氧戊环、1,4-二氧六环、二甲醚、异丙醚、正丁基醚、二丁醚、二甲氧甲烷、二甲氧丙烷、二甘醇二甲醚、12-冠醚-4、15-冠醚-5、18-冠醚-6等环状醚。
所述胺类小分子溶剂包括但不限于乙二胺二甲胺、乙二胺四甲胺、二乙二胺四甲胺等；
所述硫醚类小分子溶剂包括但不限于乙二硫醇二甲硫醚、乙二硫醇二乙硫醚、二乙二硫醇二甲硫醚、四乙二硫醇二甲硫醚等。
所述醇类小分子溶剂包括但不限于己醇、庚醇、辛醇、壬醇以及高级脂肪醇、聚乙二醇、聚乙二醇单甲醚等。
所述聚醚类聚合物包括但不限于聚环氧乙烷、聚环氧丙烷。
所述聚胺类聚合物包括但不限于聚乙二胺、聚甲基乙二胺等。
所述聚硫醇类聚合物包括但不限于聚乙二硫醇、甲基聚乙二硫醇等。
上述列举的用作溶锂剂13的物质单独使用时，对金属锂的溶解性可能较低，可通过搅拌和/或加热促进锂的溶解，但是如果选取上述的一种与其他的有机溶剂或将上述的两种或以上种类进行混合使用时，就会产生较高的金属锂溶解能力。例如，典型的溶锂剂13溶液包括但不限于四氢呋喃与正己烷的混合溶液、四氢呋喃与环己烷的混合溶液、四氢吡喃与环己烷的混合溶液、四氢呋喃与萘的混合溶液、乙二醇二甲醚与联苯的混合溶液、乙二醇二甲醚与甲苯的混合溶液、二甲醚与联苯的混合溶液、石油醚与甲苯的混合溶液、四氢呋喃与液氨的混合溶液、1,3-二氧戊环与液氨的混合溶液、乙二醇二甲醚与液氨的混合溶液、丙胺与乙二胺的混合溶液、丁胺和二氨基丙烷和乙醇的混合溶液。
所述锁定层15附着于所述集流体基体11的孔道101的孔壁上，既能与所述集流体基体11紧密结合，又能与所述溶锂剂13产生亲和作用，改善溶锂剂13的润湿性能，从而通过毛细作用将所述溶锂剂13束缚在所述集流体基体11的孔道101中。
所述锁定层15的材料选自聚偏氟乙烯(PVDF)、聚环氧乙烷(PEO)、聚丙烯酸(PAA)、 丁苯橡胶(SBR)、羧甲基纤维素(CMC)、聚吡咯(PPy)、聚丙烯腈(PAN)、植物纤维、石墨烯、氧化石墨烯、硬碳、软碳、石墨、C 3N 4、松香酸、松香甘油酯、聚乙烯醇、萘磺酸、苯甲酰胺、聚偏氟乙烯、聚乙烯亚胺、正硅酸四乙酯、聚氯乙烯、氢溴酸肼、三甲基碘化亚砜、聚四氟乙烯、聚偏二氟乙烯与六氟丙烯的共聚物、聚氨酯、聚丙烯酸酯中的至少一种。
所述锁定层15的厚度为50nm～10μm，优选的，涂覆厚度为500nm～5μm。
所述孔道101的孔壁上还可选择性地设置诱导定位层17。所述诱导定位层17与所述锁定层15相互配合控制锂离子的沉积位置，诱导锂离子的沉积方向，从而确保隔膜无刺穿风险。所述诱导定位层17的涂覆厚度为10nm～800nm。
所述诱导定位层17可以与锂离子发生化学反应或者具有极大的亲锂性质，从而诱导锂离子进入集流体基体11的孔道101内部进行沉积。所述诱导定位层17的材料可选自金、银、锡、锌、镁、铟、氧化铜、氧化锌、氧化铝、硅、锗等亲锂材料。所述诱导定位层17至少部分直接附着在孔道101的孔壁上，所述锁定层15可局部直接附着在孔道101的孔壁上且局部直接覆盖所述诱导定位层17。本实施例中，所述诱导定位层17为固体层，例如当所述锁定层15为PEO时，则所述锁定层15为液体层，所以需在所述孔道101的孔壁上先形成诱导定位层17再形成液体的锁定层15；且所述锁定层15并未完全覆盖所述诱导定位层17，所述诱导定位层17至少相对所述锁定层15局部露出以接触锂离子。
基于负极集流体10的双面应用(例如负极集流体10的双面分别对应设置有正极)，本申请的负极集流体10还可设置为双面开孔的结构，如图4所示，所述负极集流体10的集流体基体11包括相对设置的第一表面102和第二表面104；从第一表面102和第二表面104分别开设有多个孔道101，且第一表面102开设的孔道101与第二表面104开设的孔道101是相互不连通的。每一个孔道101均不贯穿所述集流体基体11，即每一个孔道101为一个盲孔。本实施例中，每一个孔道101的延伸深度约为所述集流体基体11的厚度的一半。参上所述，每一个孔道101中也设置有上述的溶锂剂13和上述的锁定层15，以及选择性的设置诱导定位层17，在此不再进行赘述。
可选的，所述无负极锂金属电池100还可选择性地包括一正负极隔离层(图未示)。所述正负极隔离层位于所述正极和所述负极集流体之间。所述正负极隔离层可以交换锂离子，从而防止集流体基体的中的溶锂剂与正极侧发生反应。所述正负极隔离层包括阳离子交换膜、固态电解质等材料。所述正负极隔离层的厚度为20μm～500μm。
本申请还提供所述负极集流体的制备方法，包括如下步骤：
提供集流体基体；
在所述集流体基体中形成多个孔道；
在所述多个孔道的孔壁上形成锁定层；
在所述孔道内填充溶锂剂。
所述制备方法工艺简单，能够通过毛细作用将所述溶锂剂束缚在所述集流体基体的孔道中。
可以理解的，所述负极集流体的制备方法还可包括在所述孔道内填充溶锂剂之前，在所述孔道的孔壁上形成诱导定位层的步骤。所述诱导定位层可以与锂离子发生化学反应或者具有极大的亲锂性质，从而诱导锂离子进入集流体基体的孔道内部进行沉积。所述诱导定位层的材料可选自金、银、锡、锌、镁、铟、氧化铜、氧化锌、氧化铝、硅、锗等亲锂材料。本实施例中，所述诱导定位层为固体层，而当锁定层选用为液体层，需在所述孔道的孔壁上先 形成诱导定位层，再形成锁定层；且所述锁定层并未完全覆盖所述诱导定位层，所述诱导定位层至少相对所述锁定层局部露出。
提供集流体基体的步骤包括提供材质可为铜、不锈钢、合金等导电材料且为薄层状的集流体基体。所述集流体基体的厚度为5μm～150μm，优选为10μm～50μm。
在所述集流体基体中形成多个孔道的步骤具体可采用激光打孔或蚀刻的方式形成具有毛细管阵列的孔道。所述多个孔道的排布可为规律排布，例如矩阵排布，也可为不规律排布，如可为泡沫类型结构。每一个孔道可以贯穿所述集流体基体，也可以不贯穿集流体基体。每一个孔道的孔径小于100μm。所述集流体基体的孔隙率为20％～85％。
在所述孔道的孔壁上形成锁定层的步骤包括：配置锁定层的溶液，然后采用液相浸渍、减压浸渍、减压引流等方法使锁定层的溶液附着在所述集流体基体的孔道的孔壁上。所述锁定层的厚度为50nm～10μm，优选的，涂覆厚度为500nm～5μm。
所述溶锂剂为具有溶解锂金属能力的液体或凝胶体。所述溶锂剂需要在惰性气氛内，将锂金属溶于有机溶液中形成锂的化合物。所述溶锂剂包括选自具备络合锂离子能力的芳香烃类小分子化合物或含芳香烃类基团的聚合物、具备络合锂离子能力的小分子溶剂(包括醚类溶剂、胺类小分子溶剂、硫醚小分子溶剂、醇类小分子溶剂)、以及具备络合锂离子能力的聚合物(包括聚醚类聚合物、聚胺类聚合物、聚硫醇类聚合物)中的至少一种，优选为两种或两种以上的种类配置而成的混合溶液。所述溶锂剂中的锂的体积摩尔浓度可为0.1～10M。将适量的锂金属溶解在上述有机混合溶液中，可以通过搅拌或加热促进金属锂的溶解过程，从而得到溶锂剂。所述溶锂剂中锂的浓度为0.1M～10M。
在所述孔道内填充溶锂剂的步骤包括：将形成有锁定层的多孔集流体基体浸泡在所述溶锂剂中，浸渍时间5min～5h，使溶锂剂完全占据集流体基体的孔道；取出后，除去多孔集流体基体表面的溶锂剂物质。可以理解的，在所述孔道内填充溶锂剂的方法不限于此。
本申请还提供了一种使用上述负极集流体的无负极锂金属电池的制备方法，具体包括如下步骤。
制备上述的负极集流体，用以取代传统的负极极片。
制备正极，正极可以采用传统的正极极片，例如在正极集流体表面涂覆正极浆料。该正极浆料包括正极活性物质、粘结剂、导电剂等，该正极活性物质包括钴酸锂材料、三元材料、富锂正极材料等。
将上述多孔集流体单元、隔膜、正极极片卷绕或叠片制成裸电芯，并在裸电芯中注入电解液，注液后进行封装，从而制备得到无负极锂金属电池。
所述电解液由溶剂和金属盐组成，溶剂包括碳酸酯类溶剂、醚类溶剂、羧酸酯类溶剂中的一种或多种。其中，所述碳酸酯类溶剂包括环状碳酸酯或链状碳酸酯，所述环状碳酸酯具体可以是碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、γ-丁内酯(GBL)、碳酸亚丁酯(BC)、氟代碳酸乙烯酯(FEC)、碳酸亚乙烯酯(VC)中的一种或多种；所述链状碳酸酯具体可以是碳酸二甲酯(DMC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)、碳酸二丙酯(DPC)中的一种或多种。所述醚类溶剂包括环状醚或链状醚，所述环状醚具体可以是1,3-二氧戊烷(DOL)、1,4-二氧惡烷(DX)、冠醚、四氢呋喃(THF)、2-甲基四氢呋喃(2-CH3-THF)，2-三氟甲基四氢呋喃(2-CF3-THF)中的一种或多种；所述链状醚具体可以是二甲氧基甲烷(DMM)、1,2-二甲氧基乙烷(DME)、二甘醇二甲醚(TEGDME)中的一种或多种。所述羧酸酯类溶剂具体可以是乙酸甲酯(MA)、乙酸乙酯(EA)、乙酸丙酯(EP)、乙酸丁酯、 丙酸丙酯(PP)、丙酸丁酯中的一种或多种。所述金属盐阴离子包括但不限于是六氟磷酸根阴离子(PF 6 -)、六氟砷酸根阴离子(AsF 6 -)、高氯酸根阴离子(ClO 4 -)、四氟硼酸根阴离子(BF 4 -)、二草酸硼酸根阴离子(B(C 2O 4) 2-，BOB -)二氟乙二酸硼酸根阴离子(BF 2C 2O 4 -，DFOB -)双氟磺酰亚胺阴离子(FSI -)、双三氟磺酰亚胺阴离子(TFSI -)中的一种或多种。
可选的，可以将上述负极集流体的使用扩展至全固态锂金属电池。此种情况下，正极侧采用正极活性物质与固态电解质一体化设计，例如，将正极活性物质、导电剂、粘结剂与固态电解质材料按照合适的比例进行混合并搅拌制备浆料，将所述浆料均匀涂覆与正极集流体表面，并真空烘烤，制得正极活性物质与固态电解质一体正极极片；将上述的负极集流体、无机固态电解质的隔膜和上述的一体化的正极极片采用叠片工艺制成无负极全固态锂金属电池。
所述的无机固态电解质包括本领域常见的氧化物固态电解质或者硫化物固态电解质，例如，氧化物固体电解质为钙钛矿型固体电解质、钠快离子导体型固体电解质(即NASICON型固体电解质)、锂快离子导体型固体电解质(即LISICON型固体电解质)、石榴石型固体电解质、或者玻璃态氧化物固体电解质等；该硫化物固体电解质为硫代-锂快离子导体型(即thio-LISICON型固体电解质)、或者玻璃态硫化物固体电解质，或以上无机固态电解质的复合物。
下面通过具体实施例对本申请实施例技术方案进行进一步的说明。
实施例1
一种无负极锂金属电池的制备，包括：
(1)采用激光打孔工艺将负极集流体基体加工为三维多孔阵列的集流体基体。
(2)配置化学镀锡液，含有的各物质及浓度为：甲基磺酸200g/L，甲基磺酸锡200g/L，硫脲70g/L，次磷酸钠10g/L，乙二胺四乙酸(EDTA)2g/L，抗坏血酸2g/L。将三维多孔阵列的集流体基体浸没于上述化学镀锡液，静置5min。之后竖直提拉三维多孔阵列集流体基体离开溶液，沥干去除集流体基体表面的水溶液。之后将集流体置于90℃下反应30min，完成后水洗去除集流体孔道内的盐分并干燥去除三维多孔阵列集流体中孔内的水分，得到涂覆于多孔集流体基体的孔道孔壁的Sn诱导定位层。
(3)将PEO溶解于THF中形成浓度为3％的均匀溶液，将孔道孔壁形成有Sn层的三维多孔阵列集流体基体浸没于上述溶液，静置5min。之后竖直提拉三维多孔阵列集流体基体离开溶液，沥干去除集流体表面的高分子溶液。60℃鼓风干燥去除三维多孔阵列集流体中孔内的溶剂，得到涂覆于多孔集流体基体孔道孔壁的PEO锁定层。
(4)在无水无氧环境(例如惰性气氛)中，将金属锂与联苯按照质量比1:22(摩尔比为1:1)溶解于乙二醇二甲醚溶液中形成均匀溶液(溶锂剂)，联苯的浓度为1M。将内部孔道孔壁形成涂覆有Sn层和PEO层的三维多孔阵列的集流体基体浸没于上述溶液中，静置5min。之后竖直提拉三维多孔阵列的集流体基体离开溶液，沥干去除集流体表面的溶锂溶液，得到涂覆有诱导定位层、锁定层和溶锂剂的三维多孔的阵列集流体基体，即负极集流体。
(5)将全氟离子交换膜浸泡在80℃，浓度为2M的LiOH溶液中，处理2小时；用去离子水洗3次；在60℃真空烘干，直到完全去除全氟离子交换膜的水分，之后置于浓度为1M的LiTFSI的乙二醇二甲醚溶液中溶胀，得到正负极隔离层。
(6)将上述制备的负极集流体、钴酸锂正极和正负极隔离层组装成纽扣电池，由正极端滴加50μL浓度为1.0mol/L的LiPF 6电解液(该LiPF 6电解液中DMC、EMC、EC重量比为1:1:1)浸润正极极片。
实施例2
一种无负极锂金属电池的制备，包括：
(1)采用激光打孔工艺将负极集流体基体加工为三维多孔阵列的集流体基体。
(2)配置如下化学镀锡液，含有的各物质及浓度为：甲基磺酸200g/L，甲基磺酸锡200g/L，硫脲70g/L，次磷酸钠10g/L，EDTA 2g/L，抗坏血酸2g/L。将三维多孔阵列的集流体基体浸没于上述溶液，静置5min。之后竖直提拉三维多孔阵列的集流体基体离开溶液，沥干去除集流体基体表面的水溶液。之后将集流体置于90℃下反应30min，完成后水洗去除集流体基体孔道内的盐分并干燥去除三维多孔阵列的集流体基体中孔内的水分，得到涂覆于多孔集流体基体的孔道孔壁的Sn诱导定位层。
(3)将PEO溶解于THF中形成浓度为3％的均匀溶液，将内部孔道涂覆有Sn层的三维多孔阵列的集流体基体浸没于上述溶液，静置5min。之后竖直提拉三维多孔阵列的集流体基体离开溶液，沥干去除集流体基体表面的高分子溶液。60℃鼓风干燥去除三维多孔阵列的集流体基体中孔内的溶剂，得到涂覆于多孔的集流体基体的孔道孔壁的PEO锁定层。
(4)在无水无氧环境中，将金属锂与联苯按照质量比1:22(摩尔比为1:1)溶解于乙二醇二甲醚溶液中形成均匀溶液(溶锂剂)，联苯的浓度为1M。将内部孔道涂覆有Sn层和PEO层的三维多孔阵列的集流体基体浸没于上述溶液中，静置5min。之后竖直提拉三维多孔阵列的集流体基体离开溶液，沥干去除集流体基体表面的溶锂溶液，得到具有诱导定位层、锁定层和溶锂剂的三维多孔阵列的集流体基体，即负极集流体。
(5)厚度为50μm的Li 7La 3Zr 2O 12(LLZO)陶瓷片作为正负极隔离层。
(6)将上述制备的负极集流体、钴酸锂正极和正负极隔离层组装成纽扣电池，由正极端滴加50μL浓度为1.0mol/L的LiPF 6电解液(该LiPF 6电解液中DMC、EMC、EC重量比为1:1:1)浸润正极极片。
实施例3
一种无负极锂金属电池的制备，包括：
(1)采用激光打孔工艺将负极集流体加工为三维多孔阵列的集流体基体。
(2)配置如下化学镀锡液，含有的各物质及浓度为：甲基磺酸200g/L，甲基磺酸锡200g/L，硫脲70g/L，次磷酸钠10g/L，EDTA 2g/L，抗坏血酸2g/L。将三维多孔阵列集流体浸没于上述溶液，静置5min。之后竖直提拉三维多孔阵列的集流体基体离开溶液，沥干去除集流体基体表面的水溶液。之后将集流体基体置于90℃下反应30min，完成后水洗去除集流体基体孔道内的盐分并干燥去除三维多孔阵列的集流体基体中孔内的水分，得到涂覆于多孔的集流体基体的孔道孔壁的Sn诱导定位层。
(3)将PEO溶解于THF中形成浓度为3％的均匀溶液，将内部孔道涂覆有Sn层的三维多孔阵列集流体基体浸没于上述溶液，静置5min。之后竖直提拉三维多孔阵列的集流体基体离开溶液，沥干去除集流体基体表面的高分子溶液。60℃鼓风干燥去除三维多孔阵列的集流体基体中孔内的溶剂，得到涂覆于多孔的集流体基体的孔道 孔壁的PEO锁定层。
(4)在无水无氧环境中，将金属锂与联苯按照质量比1:22(摩尔比为1:1)溶解于乙二醇二甲醚溶液中形成均匀溶液(溶锂剂)，联苯的浓度为1M。将内部孔道涂覆有Sn层和PEO层的三维多孔阵列的集流体基体浸没于上述溶液中，静置5min。之后竖直提拉三维多孔阵列的集流体基体离开溶液，沥干去除集流体基体表面的溶锂溶液，得到具有诱导定位层、锁定层和溶锂剂的三维多孔阵列的集流体，即负极集流体。
(5)将全氟离子交换膜浸泡在80℃，浓度为2M的LiOH溶液中，处理2小时；用去离子水洗3次；在60℃真空烘干，直到完全去除全氟离子交换膜的水分，之后置于1M LiTFSI的乙二醇二甲醚溶液中溶胀，得到正负极隔离层。
(6)制备钴酸锂固态电解质包覆的钴酸锂：称取一定量的LiLaTiO 4与钴酸锂搅拌混合均匀，置于马沸炉中在700～900℃，烧结时间为8～12h，然后对烧结产物进行粉碎处理，得到表面包覆固态电解质的钴酸锂正极材料。
(7)将上述制备的负极集流体、固态电解质保护的钴酸锂正极和正负极隔离层组装成纽扣电池，由正极端滴加50μL浓度为1.0mol/L的LiPF 6电解液(该LiPF 6电解液中DMC、EMC、EC重量比为1:1:1)浸润正极极片。
实施例4
一种无负极锂金属电池的制备，包括：
(1)采用激光打孔工艺将负极集流体加工为三维多孔阵列的集流体基体。
(2)配置如下化学镀锡液，含有的各物质及浓度为：甲基磺酸200g/L，甲基磺酸锡200g/L，硫脲70g/L，次磷酸钠10g/L，EDTA 2g/L，抗坏血酸2g/L。将三维多孔阵列集流体浸没于上述溶液，静置5min。之后竖直提拉三维多孔阵列的集流体基体离开溶液，沥干去除集流体基体表面的水溶液。之后将集流体基体置于90℃下反应30min，完成后水洗去除集流体基体的孔道内的盐分并干燥去除三维多孔阵列的集流体基体中孔内的水分，得到涂覆于多孔的集流体基体的孔道孔壁的Sn诱导定位层。
(3)将PEO溶解于THF中形成浓度为3％的均匀溶液，将内部孔道涂覆有Sn层的三维多孔阵列的集流体基体浸没于上述溶液，静置5min。之后竖直提拉三维多孔阵列的集流体基体离开溶液，沥干去除集流体基体表面的高分子溶液。60℃鼓风干燥去除三维多孔阵列的集流体基体中孔内的溶剂，得到涂覆于多孔的集流体基体的孔道孔壁的PEO锁定层。
(4)在无水无氧环境中，在玻璃瓶中加入磁子、0.6g聚乙二醇单甲醚(mPEG，M.W.＝750)、0.39g LiTFSI，加热板设置温度为200℃，开启搅拌，使锂盐完全溶解。向完全溶解完的LiTFSI的mPEG溶液中分批次加入0.264g锂片(d≈11mm)，缓慢提高转速到800rpm，形成灰色的均匀分散液。冷却至室温。向灰色分散液中加入20mL无水THF，从手套箱中取出小瓶置于超声机中超声过夜。超声完成后的液态负极再次转入手套箱中，置于加热板上，加热板设置温度为70℃，令THF挥发完全。挥发完后，将内部孔道涂覆有Sn层和PEO层的三维多孔阵列集流体放置在玻璃板上，使用辊轮将上述制备好的液态负极均匀涂敷于集流体的孔道中，将50μm LLZO陶瓷片贴合于涂敷了液态负极的集流体上，去除边缘多余的液态负极，得到 具有诱导定位层、锁定层和溶锂剂并用全固态电解质封装保护的三维多孔阵列集流体，即负极集流体。
(5)将上述制备的负极集流体和钴酸锂正极组装成纽扣电池，由正极端滴加50μL浓度为1.0mol/L的LiPF 6电解液(该LiPF 6电解液中DMC、EMC、EC重量比为1:1:1)浸润正极极片。
对比例
LiCoO 2/Li电池组装:将锂金属箔片、钴酸锂正极和Celgard隔膜组装成纽扣电池，滴加50μL浓度为1.0mol/L的LiPF6电解液(该LiPF 6电解液中DMC、EMC、EC重量比为1:1:1)。
对比测试及分析
将实施例1至4和对比例中组装得到的电池，按照0.1C/0.2C充放电制度分别进行充放电测试，锂金属的电池电压范围为3.0～4.5V，得到测试结果如表1和图5所示。
Figure PCTCN2021126301-appb-000001
从表1和图5的测试结果可知：实施例1至4的电池循环100圈后的容量保持率都远高于对比例的电池循环100圈后的容量保持率。这表明采用具有诱导定位层、锁定层和溶锂剂的三维多孔阵列集流体作负极，可显著提高电池的循环性能。这是由于该多孔集流体基体的孔道壁附着有锁定层和/或诱导定位层，孔道内填充溶锂剂，溶锂剂依靠毛细管吸附作用在孔道内稳定存在；充电时，锂离子进入该多孔的集流体单元，并与溶锂剂结合，形成液态金属锂，该液态金属锂在该集流体单元中可稳定存在，且降低锂枝晶产生的风险。
需要说明的是，以上仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内；在不冲突的情况下，本申请的实施方式及实施方式中的特征可以相互组合。因此，本申请的保护范围应以权利要求的保护范围为准。

Claims (18)

  1. 一种锂金属电池的负极集流体，其特征在于，包括：
    多孔的集流体基体，所述集流体基体中开设有多个孔道；
    溶锂剂，填充于所述集流体基体的孔道中，所述溶锂剂为具备溶解锂金属能力的液体或凝胶体；
    锁定层，附着于所述孔道的孔壁上且位于所述孔道的孔壁与所述溶锂剂之间，所述锁定层用于将所述溶锂剂束缚在所述集流体基体的孔道中。
  2. 根据权利要求1所述的负极集流体，其特征在于，每一个孔道的孔径小于100μm；且所述集流体基体的孔隙率为20％～85％。
  3. 根据权利要求1所述的负极集流体，其特征在于，所述集流体基体的厚度为5μm～150μm。
  4. 根据权利要求1所述的负极集流体，其特征在于，所述溶锂剂包括选自具备络合锂离子能力的芳香烃类小分子化合物或含芳香烃类基团的聚合物、具备络合锂离子能力的小分子溶剂、以及具备络合锂离子能力的聚合物中的至少一种；所述具备络合锂离子能力的小分子溶剂包括醚类溶剂、胺类小分子溶剂、硫醚、醇类小分子溶剂；所述具备络合锂离子能力的聚合物包括聚醚类聚合物、聚胺类聚合物、聚硫醇类聚合物。
  5. 根据权利要求4所述的负极集流体，其特征在于，所述溶锂剂中锂的体积摩尔浓度为0.1M～10M。
  6. 根据权利要求4或5所述的负极集流体，其特征在于，
    所述芳香烃类小分子化合物包括联苯、萘、菲、蒽、并四苯、芘；
    所述含芳香烃类基团的聚合物包括含有联苯、萘、菲、蒽、并四苯、芘的芳香基团的聚合物；
    所述醚类溶剂包括乙二醇二甲醚、乙二醇二乙醚、二乙二醇二甲醚、四乙二醇二甲醚、聚乙二醇二甲醚，以及四氢呋喃、四氢吡喃、2-甲基四氢呋喃、1,3-二氧戊环、4-甲基-1,3二氧戊环、1,4-二氧六环、二甲醚、异丙醚、正丁基醚、二丁醚、二甲氧甲烷、二甲氧丙烷、二甘醇二甲醚、12-冠醚-4、15-冠醚-5、18-冠醚-6；
    所述胺类小分子溶剂包括乙二胺二甲胺、乙二胺四甲胺、二乙二胺四甲胺；所述硫醚类小分子溶剂包括但不限于乙二硫醇二甲硫醚、乙二硫醇二乙硫醚、二乙二硫醇二甲硫醚、四乙二硫醇二甲硫醚；
    所述醇类小分子溶剂包括己醇、庚醇、辛醇、壬醇以及高级脂肪醇、聚乙二醇、聚乙二醇单甲醚；
    所述聚醚类聚合物包括聚环氧乙烷、聚环氧丙烷；
    所述聚胺类聚合物包括聚乙二胺、聚甲基乙二胺；
    所述聚硫醇类聚合物包括聚乙二硫醇、甲基聚乙二硫醇。
  7. 根据权利要求1所述的负极集流体，其特征在于，所述锁定层的材料选自聚偏氟乙烯、聚环氧乙烷、聚丙烯酸、丁苯橡胶、羧甲基纤维素、聚吡咯、聚丙烯腈、植物纤维、石墨烯、氧化石墨烯、硬碳、软碳、石墨、C 3N 4、松香酸、松香甘油酯、聚乙烯醇、萘磺酸、苯甲酰胺、聚偏氟乙烯、聚乙烯亚胺、正硅酸四乙酯、聚氯乙烯、氢溴酸肼、三甲基碘化亚砜、聚 四氟乙烯、聚偏二氟乙烯与六氟丙烯的共聚物、聚氨酯、聚丙烯酸酯中的至少一种。
  8. 根据权利要求7所述的负极集流体，其特征在于，该锁定层的涂覆厚度为50nm～10μm。
  9. 根据权利要求1所述的负极集流体，其特征在于，所述孔道的孔壁上还设置有诱导定位层，所述诱导定位层具备与锂离子发生化学反应或者亲锂的性质，所述诱导定位层用以与所述锁定层相互配合控制锂离子的沉积位置和沉积方向。
  10. 根据权利要求9所述的负极集流体，其特征在于，所述诱导定位层的材料选自金、银、锡、锌、镁、铟、氧化铜、氧化锌、氧化铝、硅、锗中的至少一种。
  11. 根据权利要求1至10中任一项所述的负极集流体，其特征在于，所述集流体基体包括相对设置的第一表面和第二表面；从所述第一表面和所述第二表面分别开设有多个孔道，每一个孔道均不贯穿所述集流体基体，且所述第一表面开设的孔道与所述第二表面开设的孔道是相互不连通的。
  12. 一种锂金属电池，其特征在于，包括如权利要求1至11中任一项所述的负极集流体、正极、位于所述负极集流体和所述正极之间的隔膜，所述锂金属电池直接使用所述负极集流体作为负极。
  13. 根据权利要求12所述的锂金属电池，其特征在于，所述锂金属电池还包括正负极隔离层；所述正负极隔离层位于所述正极和所述负极集流体之间；所述正负极隔离层用以交换锂离子且防止所述负极集流体中的所述溶锂剂与所述正极发生反应。
  14. 根据权利要求13所述的锂金属电池，其特征在于，所述正负极隔离层包括阳离子交换膜、固态电解质；所述正负极隔离层的厚度为20μm～500μm。
  15. 一种负极集流体的制备方法，其特征在于，包括：
    提供集流体基体；
    在所述集流体基体中形成多个孔道；
    在所述多个孔道的孔壁上形成锁定层；
    在所述孔道内填充溶锂剂，所述溶锂剂为具备溶解锂金属能力的液体或凝胶体，所述锁定层用于将所述溶锂剂束缚在所述集流体基体的孔道中。
  16. 根据权利要求15所述的负极集流体的制备方法，其特征在于，在所述集流体基体中形成多个孔道的步骤包括形成每一个孔道的孔径小于100μm且所述集流体基体的孔隙率为20％～85％。
  17. 根据权利要求15所述的负极集流体的制备方法，其特征在于，所述负极集流体的制备方法还包括在所述多个孔道的孔壁上形成所述锁定层之前，在所述孔道的孔壁上形成诱导定位层的步骤；所述诱导定位层具备与锂离子发生化学反应或者亲锂的性质，所述诱导定位层用以与所述锁定层相互配合控制锂离子的沉积位置和沉积方向。
  18. 根据权利要求17所述的负极集流体的制备方法，其特征在于，所述诱导定位层的涂覆厚度为10nm～800nm；所述诱导定位层的材料选自金、银、锡、锌、镁、铟、氧化铜、氧化锌、氧化铝、硅、锗中的至少一种。
PCT/CN2021/126301 2020-12-31 2021-10-26 负极集流体及其制备方法和锂金属电池 WO2022142639A1 (zh)

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