CN112018394A - Lithium-copper composite electrode and preparation method and application thereof - Google Patents

Lithium-copper composite electrode and preparation method and application thereof Download PDF

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CN112018394A
CN112018394A CN201910452344.9A CN201910452344A CN112018394A CN 112018394 A CN112018394 A CN 112018394A CN 201910452344 A CN201910452344 A CN 201910452344A CN 112018394 A CN112018394 A CN 112018394A
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lithium
copper
philic
pole piece
layer
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张跃钢
周飞
戎泽
何俊
徐文善
孙亢
汪利萍
张辉
周丽莎
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Anhui Mengwei New Energy Technology 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
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/661—Metal or alloys, e.g. alloy coatings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H01M4/134—Electrodes based on metals, Si or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1395—Processes of manufacture of electrodes based on metals, Si or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/40—Alloys based on alkali metals
    • H01M4/405—Alloys based on 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
    • H01M4/64—Carriers or collectors
    • H01M4/70—Carriers or collectors characterised by shape or form
    • H01M4/72—Grids
    • H01M4/74—Meshes or woven material; Expanded metal
    • H01M4/745—Expanded metal
    • 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

Abstract

The invention discloses a lithium-copper composite electrode and a preparation method and application thereof. The preparation method comprises the following steps: 1) forming a lithium-philic layer on the surface of the copper-containing pole piece; 2) and forming a metal lithium layer on the surface of the lithium-philic layer, thereby forming the lithium-copper composite electrode. The preparation method of the lithium-copper composite cathode provided by the invention has the advantages of simple process, high controllability and low cost; the method adopts different compounding methods for different lithium-philic metals, and due to the existence of the copper substrate, on one hand, the current can be uniformly distributed in the negative electrode in the charging and discharging process, the nonuniform lithium deposition can be effectively reduced, the growth of lithium dendrites is inhibited, and on the other hand, more excellent mechanical property, thermal stability and chemical stability are provided for the negative electrode.

Description

Lithium-copper composite electrode and preparation method and application thereof
Technical Field
The invention particularly relates to a lithium-copper composite electrode and a preparation method and application thereof, and belongs to the technical field of batteries.
Background
In recent years, due to the rapid development of the power battery market, the energy density requirement of the secondary battery is higher and higher, and the existing graphite lithium metal negative electrode is difficult to meet the requirement of the power battery, so the research and development of the negative electrode material with high specific capacity become a hot spot in the industry. While lithium metal is low in density (0.59 g/cm)3) The lithium ion battery has the advantages of small reduction potential (-3.04V), high theoretical specific capacity (3860mAh/g) and the like, and is considered to be an ideal negative electrode material, for example, lithium metal is used as a negative electrode in the conventional high-energy-density lithium secondary battery lithium-sulfur battery and lithium air battery. But has disadvantages ofIt is also quite obvious that uneven lithium deposition during charging and discharging results in the generation of lithium dendrites, which may pierce the separator to cause short circuit and even explosion of the battery; in the charging and discharging process, the lithium metal has obvious volume effect, so that the volume of the battery is expanded, and potential hazards are brought to the safety performance of the metal lithium battery; meanwhile, the characteristics of soft, light and very active lithium metal increase the difficulty of large-scale production and processing. Therefore, the research and development of a lithium metal cathode which is high in safety, long in cycle and easy to process and produce is urgent.
Disclosure of Invention
The invention mainly aims to provide a lithium-copper composite electrode and a preparation method and application thereof, and further overcomes the defects in the prior art.
In order to achieve the purpose, the technical scheme adopted by the invention comprises the following steps:
the embodiment of the invention provides a preparation method of a lithium-copper composite electrode, which comprises the following steps:
1) forming a lithium-philic layer on the surface of the copper-containing pole piece;
2) and forming a metal lithium layer on the surface of the lithium-philic layer, thereby forming the lithium-copper composite electrode.
The embodiment of the invention also provides the lithium copper composite electrode prepared by the preparation method.
The embodiment of the invention also provides a lithium copper composite electrode which comprises a copper substrate, a lithium-philic layer formed on the surface of the copper substrate and a metal lithium layer formed on the surface of the lithium-philic layer.
The embodiment of the invention also provides application of the lithium-copper composite electrode in preparation of a secondary battery.
The embodiment of the invention also provides a secondary battery, and the negative electrode of the secondary battery is the lithium copper composite electrode.
Compared with the prior art, the invention has the advantages that:
1) the copper substrate in the lithium-copper composite negative electrode provided by the invention can effectively increase the mechanical property, thermal stability and chemical stability of the composite electrode, improve the processability of metal lithium and reduce the production cost;
2) the lithium-copper composite cathode provided by the invention is more beneficial to uniform transfer of charges, effectively improves the uniformity of current distribution, avoids the phenomenon of lithium dendrite generation due to overlarge local current, and improves the cycle performance of the battery;
3) the lithium-copper composite negative electrode provided by the invention takes the copper mesh as the copper substrate, and the porous structure of the lithium-copper composite negative electrode provides more deposition space for excessive lithium generated in the circulation process, so that the volume expansion in the circulation process is reduced, and the safety performance of the battery is improved;
4) the lithium-copper composite negative electrode provided by the invention can effectively improve the higher performance, the electrochemical performance and the safety performance of the lithium metal negative electrode secondary battery;
5) the preparation method of the lithium-copper composite cathode provided by the invention has the advantages of simple process, high controllability and low cost; the method adopts different compounding methods for different lithium-philic metals, and due to the existence of the copper substrate, on one hand, the current can be uniformly distributed in the negative electrode in the charging and discharging process, the nonuniform lithium deposition can be effectively reduced, the growth of lithium dendrites is inhibited, and on the other hand, more excellent mechanical property, thermal stability and chemical stability are provided for the negative electrode.
Drawings
Fig. 1 is a flow chart of a method of making a lithium copper composite negative electrode in an exemplary embodiment of the invention;
FIG. 2 is a graph showing the cycle characteristics of a secondary battery fabricated using a modified lithium copper composite negative electrode obtained in example 1 of the present invention;
FIG. 3 is a graph showing the cycle characteristics of a secondary battery fabricated by using a modified lithium copper composite negative electrode obtained in example 2 of the present invention;
FIG. 4 is a graph showing the cycle characteristics of a secondary battery fabricated using a modified lithium copper composite negative electrode obtained in example 3 of the present invention;
FIG. 5 is a graph showing the cycle characteristics of a secondary battery fabricated using a modified lithium copper composite negative electrode obtained in example 4 of the present invention;
FIG. 6 is a graph showing the cycle characteristics of a secondary battery fabricated using a modified lithium copper composite negative electrode obtained in example 5 of the present invention;
fig. 7 is a cycle curve diagram of a secondary battery prepared by using the modified lithium copper composite anode obtained in comparative example 1 according to the present invention.
Detailed Description
In view of the deficiencies in the prior art, the inventors of the present invention have made extensive studies and extensive practices to provide technical solutions of the present invention. The technical solution, its implementation and principles, etc. will be further explained as follows.
The embodiment of the invention provides a preparation method of a lithium-copper composite electrode, which comprises the following steps:
1) forming a lithium-philic layer on the surface of the copper-containing pole piece;
2) and forming a metal lithium layer on the surface of the lithium-philic layer, thereby forming the lithium-copper composite electrode.
Furthermore, the material of the lithium-philic layer comprises a lithium-philic compound.
Further, the lithium-philic compound comprises a lithium-philic active metal compound MxOyAnd a lithium-philic non-active metal compound NxOyAny one of them.
Further, M includes any one of Zn and Sn, and N includes any one of Ni, Mn, and Co, but is not limited thereto.
In some more specific embodiments, step 1) comprises: heating the pole piece containing Cu and M for 1-5h under the conditions of oxygen atmosphere and 200-500 ℃, and further forming the lithium-philic layer on the surface of the pole piece containing copper, wherein the lithium-philic layer is a lithium-philic active metal compound MxOyThe pole piece containing Cu and M is an alloy formed by Cu and M.
In some specific embodiments, step 1) specifically includes: placing the copper-containing pole piece into a reaction solution of chemical immersion plating, reacting for 0.5-16 h at 100-200 ℃, heating the copper-containing pole piece after reaction treatment for 1-5h at 200-400 ℃ in a protective atmosphere, and further forming the lithium-philic layer on the surface of the copper-containing pole piece, wherein the lithium-philic layer is a lithium-philic non-active metalCompound NxOyThe copper-containing pole piece comprises a pure copper pole piece or a copper-containing alloy.
In some more specific embodiments, the step 1) further includes: preferably, the protective atmosphere comprises an inert atmosphere.
In some more specific embodiments, the lithium-philic layer is NiO2Or NiO, forming the NiO2Or the reaction solution adopted by NiO comprises NiCl with the concentration of 0.05-0.2 mol/L2、0.2～0.8mol/L CO(NH2)2The mixed solution of (1);
in some more specific embodiments, the lithium-philic layer is MnO2Forming said MnO2The adopted reaction solution comprises 0.01-0.1 mol/L MnSO4、0.01～0.1mol/L KMnO4And 20-60 mL of deionized water.
In some specific embodiments, the lithium-philic layer is CoO, and the reaction solution for forming the CoO comprises Co (NO) in an amount of 0.1-0.5 mol/L3)2·6H2O and 0.05-0.2 mol/L CO (NH)2)2The mixed solution of (1).
In some more specific embodiments, the step 2) includes: and placing molten metal lithium on the surface of the lithium-philic layer, and then cooling for 30-60 min to further form the metal lithium layer.
In some more specific embodiments, the preparation method further comprises: cleaning the copper-containing pole piece before the step 1).
Preferably, the cleaning treatment comprises: and cleaning the copper-containing pole piece by using a cleaning agent, and then drying at 50-100 ℃ under a vacuum condition.
Preferably, the cleaning agent includes any one or a combination of two or more of acetone, ethanol and distilled water, but is not limited thereto.
Furthermore, the pole piece containing copper is of a sheet-shaped or net-shaped structure.
The embodiment of the invention also provides the lithium copper composite electrode prepared by the preparation method.
The embodiment of the invention also provides a lithium copper composite electrode which comprises a copper substrate, a lithium-philic layer formed on the surface of the copper substrate and a metal lithium layer formed on the surface of the lithium-philic layer.
Furthermore, the material of the lithium-philic layer comprises a lithium-philic compound.
Further, the lithium-philic compound comprises a lithium-philic active metal compound MxOyAnd a lithium-philic non-active metal compound NxOyThe M includes any one of Zn and Sn, and the N includes any one of Ni, Mn, and Co, but is not limited thereto.
Furthermore, the material of the copper substrate comprises pure copper or an alloy containing copper.
Further, the copper-containing alloy includes an alloy mainly composed of Cu and M or N.
Further, the copper substrate is of a sheet-shaped or net-shaped structure.
Furthermore, the thickness of the copper substrate is 10-50 μm.
Furthermore, the mesh number of the copper substrate of the net-shaped structure is 5-500 meshes.
Further, the thickness of the lithium-philic layer is 20-50 μm.
Further, the thickness of the metal lithium layer is 200-800 μm.
Further, the mass of the lithium copper composite electrode is 300-600 mg.
The embodiment of the invention also provides application of the lithium-copper composite electrode in preparation of a secondary battery.
The embodiment of the invention also provides a secondary battery, and the negative electrode of the secondary battery is the lithium copper composite electrode.
Further, the secondary battery includes a lithium sulfur battery, a lithium air battery or a lithium ion battery.
The technical solution, its implementation and principles, etc. will be further explained as follows.
FIG. 1 shows a novel lithium-copper composite negative electrode of the inventionThe flow chart of the preparation method should be noted that the lithium metal cathode is very active in chemical property and can react with O in the air2、H2O、CO2And the lithium copper metal negative plate and the secondary battery are assembled in a dry glove box filled with argon, wherein the water content is less than or equal to 0.5ppm, and the oxygen content is less than or equal to 0.5 ppm.
Specifically, the lithium-copper composite electrode comprises a copper substrate, a lithium-philic layer formed on the surface of the copper substrate, and a metal lithium layer formed on the surface of the lithium-philic layer.
The material of the copper substrate can be pure copper or copper-containing alloy, and the structure can be copper foil (namely the sheet structure) or copper mesh (namely the mesh structure); the lithium-philic layer can be a lithium-philic compound or a simple metal; wherein the lithiophilic compound comprises a lithiophilic active metal compound MxOyAnd a lithium-philic non-active metal compound NxOyThe M comprises any one of Zn and Sn, and the N comprises any one of Ni, Mn and Co.
The modified lithium-copper composite electrode obtained by the invention has stable cycle performance, can effectively inhibit the generation of dendritic crystals of a lithium metal negative electrode, and can be widely applied to novel high specific energy electrochemical energy storage devices, such as lithium ion batteries, lithium air batteries, lithium sulfur batteries and the like.
The invention provides a novel lithium-copper composite cathode preparation method with simple process, high controllability and low cost, which adopts different composite methods for different lithium-philic metals.
Specifically, the preparation method of the lithium-copper composite electrode comprises the following steps:
1) cleaning the copper-containing pole piece by using acetone, ethanol and distilled water in sequence, circularly cleaning for 3 times, placing the pole piece in a vacuum drying oven, drying at 50-100 ℃ for 24 hours, and then cutting;
2) a lithium-philic layer which mainly consists of a lithium-philic compound or a metal simple substance is manufactured and formed on the surface of the copper-containing pole piece by a physical method or a chemical method, and the copper-containing pole piece is completely coated by the lithium-philic layer;
3) uniformly pouring molten metal lithium on a copper-containing pole piece with the surface coated with a lithium-philic layer, cooling for 30-60 min, and forming a metal lithium layer on the surface of the lithium-philic layer so as to form the lithium-copper composite electrode;
4) firstly, rolling the lithium-copper composite pole piece by using a roller with a clean and flat surface to enable the surface of the lithium-copper composite pole piece to be flat, and then transversely polishing the surface of the lithium-copper composite pole piece by using a polishing rod (500-1000 meshes) until the surface of the lithium-copper composite pole piece presents shiny silvery metallic luster, thus obtaining the final lithium-copper composite electrode.
Specifically, when the copper-containing pole piece is of a mesh structure, that is, when a copper mesh is adopted as the copper-containing pole piece for preparing the composite electrode, the porous structure (or the mesh structure) of the composite electrode provides more deposition space for excessive lithium generated in a circulation process (here, the lithium copper composite electrode is adopted as an anode to assemble a battery for charge and discharge circulation), so that generation and volume expansion of dendrites are effectively reduced, and meanwhile, the lithium copper composite electrode has a larger specific surface area relative to a lithium piece, so that charge transfer is facilitated, and local current density is reduced.
Specifically, the lithium-philic compound comprises a lithium-philic active metal compound MxOyAnd a lithium-philic non-active metal compound NxOyThe M comprises any one of Zn and Sn, and the N comprises any one of Ni, Mn and Co.
In some more specific embodiments, the lithium-philic active metal compound M may be formed by physical means, since the lithium-philic active metal may react with oxygen before the copper and may reduce the copper oxidexOyThe reaction principle is as follows:
2xM+yO2→2MxOy；
xM+yCuO→MxOy+yCu；
correspondingly, the lithium-philic active metal compound M is prepared and formed by a physical methodxOyThe correspondingly employed copper-containing pole pieces are alloys comprising Cu and M (M is Zn, Sn, etc.), for example commercial brass (Cu/Zn alloy, mass fraction of Zn is 20-50%) and commercial bronze (Cu/Sn alloy, mass fraction of Sn is 5-10%).
Specifically, the lithium-philic active metal compound M is formed by a physical methodxThe process of O comprises the following steps: and (3) placing the cleaned brass or bronze pole piece in a tube furnace, heating to 200-500 ℃ in an oxygen atmosphere, and reacting for 1-5h to form the copper-containing pole piece with the surface coated with the lithium-philic active metal oxide layer.
Specifically, brass (Cu/Zn alloy) provides a Zn source for in-situ growth of ZnO, and bronze (Cu/Sn alloy) is SnO2The in-situ growth of the silicon nitride provides a Sn source, so that the preparation materials are reduced, the preparation cost is reduced, the preparation process is simplified, and the controllability of the preparation process is improved; and, because of the lower stacking fault energy of brass, bronze, etc., it can be ensured that the lithium-philic active metal (Zn, Sn, etc.) atoms are uniformly diffused to the copper surface at high temperature (part or all of M in the copper alloy can be diffused to the surface as long as enough lithium-philic active metal compound is formed), thereby forming uniform lithium-philic active metal compound (ZnO, SnO, etc.)2) Layer, avoiding lithium-philic active metal compounds (ZnO, SnO) caused by insufficient chemical reaction2) The non-uniformity of the layer occurs, so that the lithium metal layer formed by casting later is more uniform, and the lithium/lithium-philic active metal compound (Cu/M) is formedxOyThe composite electrode has more excellent electrochemical performance and mechanical performance; and in addition, the physical method process only relates to high-temperature annealing, and compared with a chemical method, the method has the advantages of less control variables, low equipment requirement and simple preparation flow, so that the method is easier to expand production and has greater commercial application potential.
In other specific embodiments, the lithium-philic non-active metal N (Ni, Mn, Co, etc.) is chemically inactive and is difficult to reduce CuO produced in a high-temperature process, so that the lithium-philic non-active metal N can be prepared only by a chemical method, which increases the selection range of lithium-philic metals and provides more preparation schemes for the preparation of lithium-copper composite electrodes; wherein the chemical method comprises chemical immersion plating.
Specifically, the lithium-philic active metal compound N is formed by a physical methodxOyThe process comprises the following steps: placing the cleaned copper-containing pole piece into a 100mL polytetrafluoroethylene lining stainless steel autoclave, adding 60-80 mL reaction liquid, reacting for 0.5-16 h at 100-200 ℃, alternately cleaning the reacted copper-containing pole piece for several times by using ethanol and deionized water, drying, and finally treating the dried copper-containing pole piece for 1-5h at 200-400 ℃ in a tubular furnace filled with argon atmosphere to form the lithium-philic non-active metal compound NxOyA layer; the copper-containing pole piece may be pure copper or a copper-containing alloy, such as an alloy containing Cu and N.
In some more specific embodiments, the reaction solution employed is different for different lithium-philic non-active metal compounds, for example:
when the lithium-philic non-active metal compound is NiO, the adopted reaction solution comprises NiCl with the concentration of 0.05-0.2 mol/L2、0.2～0.8mol/L CO(NH2)2The mixed solution of (1); the chemical reaction principle is as follows:
Figure BDA0002075532570000071
NiCl2+2NH3·H2O→Ni(OH)2↓+2NH4Cl；
when the lithium-philic non-active metal compound is MnO2In the case, the reaction solution used comprises a solution containing 0.01 to 0.1mol/LKMNO40.1-0.5 mL of concentrated HCl (mass fraction is 37%) and 60mL of deionized water; the chemical reaction principle is as follows:
3MnSO4+2KMnO4+2H2O→5MnO2↓+K2SO4+2H2SO4；
when the lithium-philic non-active metal compound is CoO, the adopted reaction solution comprises 0.1-0.5 mol/L Co (NO)3)2·6H2O、0.05～0.2mol/L C6H12N4The chemical reaction principle of the mixed solution is as follows:
Figure BDA0002075532570000072
Co(NO3)2+2NH3·H2O→Co(OH)2↓+2NH4(NO3)2；
based on the above chemical reaction principle, it can be seen that some materials such as MnO are formed for fabrication2When lithium-philic non-active metal oxide is adopted, the copper-containing pole piece can be obtained by direct reaction after the reaction in the reaction solution, and when the lithium-philic non-active metal oxide such as nickel oxide, cobalt oxide and the like is adopted, after the reaction treatment of the copper-containing pole piece in the reaction solution, Ni (OH) is generated on the surface of the copper-containing pole piece2、Co(OH)2And the reacted copper-containing pole piece is treated in a tubular furnace filled with argon atmosphere at 200-400 ℃ for 1-5h to obtain NiO and CoO correspondingly.
In some specific embodiments, the step 3) includes: placing weighed metal lithium on a high-temperature heating table in a glove box filled with argon, and heating for 2-5 hours at 100-500 ℃ until molten metal lithium is formed, wherein the molten metal lithium is in a silvery white ball shape; and then placing molten metal lithium at the central part of the lithium-philic layer, uniformly coating the lithium-philic layer with the metal lithium, and cooling for 30-60 min to form the metal lithium layer. Compared with the existing physical extrusion method, the method (molten lithium pouring) can better bond the lithium layer, the lithium-philic layer and the copper-containing pole piece, and meanwhile, when the 3D copper mesh is adopted as the copper-containing pole piece, the molten lithium can be fully diffused to the surface of the copper mesh, so that the incomplete covering condition of the metal lithium layer is avoided.
Exemplary embodiments of the present invention will be described below with reference to the accompanying drawings.
Example 1
1) In a glove box, a commercially available brass mesh (mesh number 30 mesh/cm)2) Cutting with long-edge scissors to obtain a rectangular brass pole piece with the size of 6 multiplied by 8.5cm, cleaning the brass pole piece with acetone, ethanol and distilled water in sequence for 3 times in a circulating manner, and then placing the brass pole piece in a vacuum drying oven at 200 ℃ for drying treatment for 24 hours; then placing the cleaned brass pole piece in a tube furnace, heating to 200-500 ℃ in air atmosphere, and reacting for 3h to form a copper-containing pole piece with the surface coated with a zinc oxide layer;
2) in a glove box filled with argon, 300mg of metal lithium is placed on a high-temperature heating table and is heated for 2 hours at 300 ℃ to be in a molten state, and the molten metal lithium is in a silver white ball shape; placing molten metal lithium at the center of the treated zinc oxide layer, covering the surface of the zinc oxide layer with the metal lithium, cooling for 60min to form a metal lithium layer, and obtaining a lithium-copper composite pole piece with the surface coated with the metal lithium layer;
3) firstly, rolling a composite pole piece by using a roller with a clean and flat surface to flatten the surface of the composite pole piece, and then transversely polishing the surface of the lithium-copper composite pole piece by using a polishing rod (500-1000 meshes) until the surface of the lithium-copper composite pole piece presents shiny silvery metallic luster, thus obtaining the lithium-copper composite pole piece;
4) coating a diaphragm on the prepared lithium-copper composite pole piece and then assembling the lithium-copper composite pole piece to form a secondary battery, wherein the secondary battery is a lithium-sulfur secondary soft package battery, the positive electrode comprises sulfur, a conductive agent and a binder, the negative electrode is a lithium-copper composite negative electrode, and the electrolyte is LiTFSI/DME-DOL (0.1-5% LiNO)3As an additive), the assembled battery was placed on a battery test apparatus to test, and a cycle curve of the secondary battery was obtained as shown in fig. 2.
Example 2
This embodiment is substantially the same as embodiment 1 described above; except that the copper-containing electrode sheet used in example 2 was a commercial bronze mesh (30 mesh/cm mesh)2) Otherwise, the same procedure as in example 1 was repeated, and an assembled secondary battery was obtained as in example 1The cycle curve of the secondary battery is shown in fig. 3.
Example 3
1) Cutting commercially-purchased pure copper foil (with the thickness of 30 mu m) in a glove box by using long-edge scissors to obtain a rectangular copper pole piece with the size of 6 multiplied by 8.5cm, sequentially cleaning the copper pole piece by using acetone, ethanol and distilled water for 3 times in a circulating manner, and then placing the copper pole piece in a vacuum drying oven at 80 ℃ for drying for 24 hours;
2) 0.75g of NiCl2Dissolving the solid and 0.42g of urea in 60mL of deionized water, and magnetically stirring at the rotating speed of 100-500 rpm for 10-40 min to form a clear solution, namely the reaction solution;
3) placing the cleaned copper pole piece into a 100mL stainless steel autoclave with a polytetrafluoroethylene lining, adding 60mL prepared reaction liquid, and reacting at 100-200 ℃ for 0.5-16 h; washing the reacted copper pole piece with distilled water for 3 times, drying at 120 ℃ for 4h, then placing the copper pole piece in a tubular furnace, and reacting at 350 ℃ for 4h under the argon atmosphere to form the copper pole piece with the surface coated with nickel oxide (NiO);
4) in a glove box filled with argon, 300mg of metallic lithium is placed on a high-temperature heating table and heated for 2 hours at 300 ℃ to be molten, and the molten metallic lithium is silvery white and spherical; placing molten metal lithium at the central part of the nickel oxide layer, enabling the metal lithium to cover the surface of the nickel oxide layer, cooling for 60min to form a metal lithium layer, and obtaining a lithium-copper composite pole piece with the surface coated with the nickel oxide layer;
5) firstly, rolling a lithium-copper composite pole piece by using a roller with a clean and flat surface to flatten the surface of the lithium-copper composite pole piece, and then transversely polishing the surface of the lithium-copper composite pole piece by using a polishing rod (500-1000 meshes) until the surface of the lithium-copper composite pole piece presents shiny silvery metallic luster, so as to obtain the lithium-copper composite negative pole piece;
6) a lithium-copper composite pole piece coated diaphragm is adopted as a lithium cathode to be assembled into a secondary battery, the secondary battery is a lithium-sulfur secondary soft package battery, the positive electrode of the secondary battery comprises sulfur, a conductive agent and a binder, and an electrolyte is LiTFSI/DME-DOL (0.1-5% LiNO)3As an additive), the assembled battery is placed inThe cycle curve of the secondary battery obtained by the detection on the battery test equipment is shown in fig. 4.
Example 4
1) Cutting commercially-purchased pure copper foil (with the thickness of 30 mu m) in a glove box by using long-edge scissors to obtain a rectangular copper pole piece with the size of 6 multiplied by 8.5cm, sequentially cleaning the copper pole piece by using acetone, ethanol and distilled water for 3 times in a circulating manner, and then placing the copper pole piece in a vacuum drying oven at 80 ℃ for drying for 24 hours;
2) 2.535g of MnSO4Dissolved in 50mL of deionized water, and 1.58g of KMnO was weighed4Mixing with 60mL of deionized water, and adding MnSO4The solution was slowly added to KMnO4In the solution, magnetically stirring for 10-40 min at the rotating speed of 100-500 rpm to form a clear solution as a reaction solution;
3) placing the cleaned copper pole piece in a 100mL stainless steel autoclave with a polytetrafluoroethylene lining, adding 60mL prepared reaction liquid, reacting for 0.5h at 140 ℃, cleaning the copper pole piece with distilled water for 3 times, and drying at 120 ℃ for 4h to form manganese oxide (MnO) coated on the surface2) The copper pole piece of (1);
4) in a glove box filled with argon, 300mg of metal lithium is placed on a high-temperature heating table and heated for 2 hours at the temperature of 300 ℃ until the metal lithium is molten, the molten metal lithium is silvery white and spherical, the molten metal lithium is placed at the central part of the processed manganese oxide layer, the metal lithium covers the surface of the manganese oxide layer, and the metal lithium layer is formed after cooling for 60 minutes, so that the composite pole piece with the surface coated with the metal lithium layer is obtained;
5) firstly, rolling a composite pole piece by using a roller with a clean and flat surface to flatten the surface of the composite pole piece, and then transversely polishing the surface of the lithium-copper composite pole piece by using a polishing rod (500-1000 meshes) until the surface of the lithium-copper composite pole piece presents shiny silvery metallic luster, thus obtaining the lithium-copper composite pole piece;
6) a lithium-copper composite pole piece coated diaphragm is adopted as a lithium cathode to be assembled into a secondary battery, the secondary battery is a lithium-sulfur secondary soft package battery, the positive electrode of the secondary battery comprises sulfur, a conductive agent and a binder, and an electrolyte is LiTFSI/DME-DOL (0.1-5% LiNO)3As an additive), the assembled battery was placed on a battery test apparatus to test, and a cycle curve of the secondary battery was obtained as shown in fig. 5.
Example 5
1) Cutting commercially-purchased pure copper foil (with the thickness of 30 mu m) in a glove box by using long-edge scissors to obtain a rectangular copper pole piece with the size of 6 multiplied by 8.5cm, sequentially cleaning the copper pole piece by using acetone, ethanol and distilled water, circularly cleaning for 3 times, and then placing the copper pole piece in a vacuum drying box at the temperature of 80 ℃ to dry for 24 hours;
2) 1.75g of Co (NO)3)2Dissolving the solid and 0.36g of urea solid in 60mL of deionized water, and magnetically stirring at the rotating speed of 100-500 rpm for 10-40 min to form a clear solution as a reaction solution;
3) placing the cleaned copper pole piece into a 100mL stainless steel autoclave with a polytetrafluoroethylene lining, adding 60mL prepared reaction liquid, reacting for 0.5-16 h at 100-200 ℃, cleaning the reacted copper pole piece with distilled water for 3 times, drying for 4h at 120 ℃, placing the copper pole piece into a tubular furnace, and heating and reacting for 2.5h at 250 ℃ in an argon atmosphere to form the copper pole piece with the surface coated with cobalt oxide (CoO);
4) in a glove box filled with argon, 300mg of metal lithium is placed on a high-temperature heating table and heated for 2 hours at 300 ℃ until the metal lithium is molten, the molten metal lithium is silvery white and spherical, the molten metal lithium is placed at the central part of the treated cobalt oxide layer, the metal lithium covers the surface of the cobalt oxide layer, and the metal lithium layer is formed after cooling for 60 minutes, so that the composite pole piece with the surface coated with the metal lithium layer is obtained;
5) firstly, rolling a composite pole piece by using a roller with a clean and flat surface to flatten the surface of the composite pole piece, and then transversely polishing the surface of the lithium-copper composite pole piece by using a polishing rod (500-1000 meshes) until the surface of the lithium-copper composite pole piece presents shiny silvery metallic luster, thus obtaining the lithium-copper composite pole piece;
6) the lithium-copper composite pole piece coated diaphragm is adopted as a lithium cathode to be assembled into a secondary battery, the secondary battery is a lithium-sulfur secondary soft package battery, and the anode of the secondary battery comprises sulfur, a conductive agent, a binder and electrolyteIs LiTFSI/DME-DOL (0.1-5% LiNO)3As an additive), the assembled battery was placed on a battery test apparatus to test, and a cycle curve of the secondary battery was obtained as shown in fig. 6.
Comparative example 1
1) In a glove box, commercially available lithium tapes (thickness 100 μm) were cut with long-edge scissors to obtain rectangular lithium metal pole pieces of 6 × 8.5cm in size;
2) firstly, rolling a lithium sheet by using a roller with a clean and flat surface to flatten the surface of the lithium sheet, and then transversely polishing the surface of the lithium sheet by using a polishing rod (500-1000 meshes) until the surface of the lithium sheet presents a shiny silvery white metal luster, thus obtaining the lithium sheet;
3) coating a diaphragm on the prepared lithium pole piece to form a lithium cathode, and assembling the lithium cathode into a secondary battery, wherein the battery system is a lithium-sulfur secondary soft package battery, the anode is sulfur, a conductive agent and an adhesive, the cathode is a lithium metal cathode, and the electrolyte is LiTFSI/DME-DOL (0.1-5% LiNO)3As an additive), the assembled battery was placed on a battery test apparatus to test, and a secondary battery cycle curve was obtained as shown in fig. 7.
Comparing the cycle curves shown in fig. 2-7, the novel lithium-copper composite electrode shows better electrochemical performance, wherein the copper/zinc oxide/lithium negative electrode (fig. 2) decays to 80% of the initial capacity at 65 circles, the copper/tin oxide/lithium negative electrode (fig. 3) decays to 80% of the initial capacity at 47 circles, the copper/nickel oxide/lithium negative electrode (fig. 4) decays to 80% of the initial capacity at 54 circles, the copper/manganese oxide/lithium negative electrode (fig. 5) decays to 80% of the initial capacity at 51 circles, and the copper/cobalt oxide/lithium negative electrode (fig. 6) decays to 80% of the initial capacity at 47 circles, which are better than the pure lithium negative electrode (fig. 7) decays to 80% of the initial capacity at 11 circles, which illustrates that the method has obvious improvement effect on the cell cycle performance; meanwhile, the method has the advantages of simple operation process, strong controllability and wider application prospect.
It should be noted that bronze, brass, pure copper, copper-containing alloy, and the like used in the embodiments of the present invention are commercially available, and the copper content of pure copper is greater than 99.5%.
The invention provides a novel lithium-copper composite negative electrode and a preparation method thereof, wherein a copper substrate in the formed lithium-copper composite negative electrode can effectively increase the mechanical property, the thermal stability and the chemical stability of a composite electrode, improve the processability of metal lithium and reduce the production cost; the composite electrode is more beneficial to uniform transfer of charges, effectively improves the uniformity of current distribution, avoids the phenomenon of lithium dendrite generation due to overlarge local current, and improves the cycle performance of the battery; in addition, when the copper mesh is used as a copper substrate, the porous structure of the lithium-copper composite negative electrode provides more deposition space for excessive lithium generated in the circulation process, reduces volume expansion in the circulation process, and improves the safety performance of the battery; therefore, the composite electrode can effectively improve the higher performance, the electrochemical performance and the safety performance of the lithium metal cathode secondary battery.
It should be understood that the above-mentioned embodiments are merely illustrative of the technical concepts and features of the present invention, which are intended to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and therefore, the protection scope of the present invention is not limited thereby. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims (10)

1. A preparation method of a lithium-copper composite electrode is characterized by comprising the following steps:
1) forming a lithium-philic layer on the surface of the copper-containing pole piece;
2) and forming a metal lithium layer on the surface of the lithium-philic layer, thereby forming the lithium-copper composite electrode.
2. The method of claim 1, wherein: the material of the lithium-philic layer comprises a lithium-philic compound; and/or, the lithium-philic compound comprises a lithium-philic active metal compound MxOyAnd a lithium-philic non-active metal compound NxOyAny one of the above; and/or, the M comprises any one of Zn and Sn, and the N comprises any one of Ni, Mn and Co.
3. The method of claim 2, wherein step 1) comprises: heating a pole piece containing Cu and M for 1-5h under the conditions of oxygen atmosphere and 200-500 ℃, and further forming a lithium-philic layer on the surface of the copper-containing pole piece, wherein the lithium-philic layer is a lithium-philic active metal compound MxOyThe pole piece containing Cu and M is an alloy formed by Cu and M.
4. The method according to claim 2, wherein step 1) comprises: placing the copper-containing pole piece into a reaction solution of chemical immersion plating, reacting for 0.5-16 h at 100-200 ℃, heating the copper-containing pole piece after reaction treatment for 1-5h at 200-400 ℃ in a protective atmosphere, and further forming the lithium-philic layer on the surface of the copper-containing pole piece, wherein the lithium-philic layer is a lithium-philic non-active metal compound NxOyThe copper-containing pole piece comprises pure copper or copper-containing alloy; preferably, the protective atmosphere comprises an inert atmosphere.
5. The method of claim 4, wherein: the lithium-philic layer is NiO, and the reaction solution for forming the NiO comprises NiCl in an amount of 0.05-0.2 mol/L2、0.2～0.8mol/L CO(NH2)2The mixed solution of (1); and/or, the lithium-philic layer is MnO2Forming said MnO2The adopted reaction solution comprises 0.01-0.1 mol/L MnSO4、0.01～0.1mol/L KMnO4The mixed solution of (1); and/or the lithium-philic layer is CoO, and the reaction liquid for forming the CoO comprises Co (NO) with the concentration of 0.1-0.5 mol/L3)2·6H2O and 0.05-0.2 mol/L CO (NH)2)2The mixed solution of (1).
6. The method for preparing according to claim 1, wherein the step 2) comprises: placing molten metal lithium on the surface of the lithium-philic layer, and then cooling for 30-60 min to further form the metal lithium layer; and/or, the preparation method further comprises the following steps: cleaning the copper-containing pole piece before the step 1); preferably, the cleaning treatment comprises: cleaning the copper-containing pole piece by using a cleaning agent, and then drying at 50-100 ℃ under a vacuum condition; preferably, the cleaning agent comprises any one or the combination of more than two of acetone, ethanol and distilled water; and/or the copper-containing pole piece is of a sheet-shaped or net-shaped structure.
7. A lithium-copper composite electrode produced by the production method according to any one of claims 1 to 6.
8. A lithium-copper composite electrode is characterized by comprising a copper substrate, a lithium-philic layer formed on the surface of the copper substrate and a metal lithium layer formed on the surface of the lithium-philic layer; and/or the material of the lithium-philic layer comprises a lithium-philic compound; and/or, the lithium-philic compound comprises a lithium-philic active metal compound MxOyAnd a lithium-philic non-active metal compound NxOyM comprises any one of Zn and Sn, and N comprises any one of Ni, Mn and Co; and/or the material of the copper substrate comprises pure copper or an alloy containing copper; and/or, the copper-containing alloy comprises an alloy consisting essentially of Cu with M or N; and/or the copper substrate is of a sheet-shaped or net-shaped structure; and/or the thickness of the copper substrate is 10-50 μm; and/or the mesh number of the copper substrate of the net structure is 5-500 meshes; and/or the thickness of the lithium-philic layer is 20-50 μm; and/or the thickness of the metal lithium layer is 200-800 μm; and/or the mass of the lithium copper composite electrode is 300-600 mg.
9. Use of the lithium copper composite electrode according to claim 7 or 8 for the preparation of a secondary battery.
10. A secondary battery, characterized in that: the negative electrode of the secondary battery is the lithium copper composite electrode according to any one of claims 7 to 8; and/or the secondary battery comprises a lithium sulfur battery, a lithium air battery or a lithium ion battery.
CN201910452344.9A 2019-05-28 2019-05-28 Lithium-copper composite electrode and preparation method and application thereof Pending CN112018394A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114023944A (en) * 2021-11-10 2022-02-08 电子科技大学长三角研究院(湖州) Cobalt protoxide nanosheet-sponge nickel/metal lithium composite material and preparation method and application thereof
CN114400331A (en) * 2022-03-03 2022-04-26 电子科技大学 Preparation method of negative current collector capable of improving lithium metal cycle stability
CN116936815A (en) * 2023-09-18 2023-10-24 宁德时代新能源科技股份有限公司 Negative current collector, preparation method thereof, negative electrode plate, lithium metal battery and power utilization device

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114023944A (en) * 2021-11-10 2022-02-08 电子科技大学长三角研究院(湖州) Cobalt protoxide nanosheet-sponge nickel/metal lithium composite material and preparation method and application thereof
CN114400331A (en) * 2022-03-03 2022-04-26 电子科技大学 Preparation method of negative current collector capable of improving lithium metal cycle stability
CN116936815A (en) * 2023-09-18 2023-10-24 宁德时代新能源科技股份有限公司 Negative current collector, preparation method thereof, negative electrode plate, lithium metal battery and power utilization device
CN116936815B (en) * 2023-09-18 2024-02-27 宁德时代新能源科技股份有限公司 Negative current collector, preparation method thereof, negative electrode plate, lithium metal battery and power utilization device

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