CN109686923B - Preparation method of pre-lithium-intercalated negative electrode, pre-lithium-intercalated negative electrode prepared by preparation method, energy storage device, energy storage system and electric equipment - Google Patents

Preparation method of pre-lithium-intercalated negative electrode, pre-lithium-intercalated negative electrode prepared by preparation method, energy storage device, energy storage system and electric equipment Download PDF

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CN109686923B
CN109686923B CN201811545143.5A CN201811545143A CN109686923B CN 109686923 B CN109686923 B CN 109686923B CN 201811545143 A CN201811545143 A CN 201811545143A CN 109686923 B CN109686923 B CN 109686923B
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lithium
energy storage
negative electrode
storage device
metal
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CN109686923A (en
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唐永炳
张阁
欧学武
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Shenzhen Institute of Advanced Technology of CAS
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/134—Electrodes based on metals, Si or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/04—Hybrid capacitors
    • H01G11/06—Hybrid capacitors with one of the electrodes allowing ions to be reversibly doped thereinto, e.g. lithium ion capacitors [LIC]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/84—Processes for the manufacture of hybrid or EDL capacitors, or components thereof
    • H01G11/86—Processes for the manufacture of hybrid or EDL capacitors, or components thereof specially adapted for electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • 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
    • 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 relates to the field of new energy, and particularly provides a preparation method of a pre-lithium-intercalated negative electrode, the prepared pre-lithium-intercalated negative electrode, an energy storage device, an energy storage system and electric equipment. The preparation method of the pre-embedded lithium cathode comprises the steps of providing a half battery, and charging or discharging the half battery; the working electrode of the half cell is made of a metal material, the counter electrode is made of a material capable of providing a lithium source, and the electrolyte is a lithium salt solution containing an additive; the metal material comprises a metal, an alloy or a metal composite material capable of undergoing an alloying reaction with lithium ions; the additive includes a substance capable of decomposing and forming an SEI film on the surface of the metal material. The method has simple process and low cost, the SEI passive film can be formed on the surface of the metal material by the method, the negative electrode is prevented from volume expansion and pulverization, so that the stability of the negative electrode is improved, and the alloy formed by pre-embedding lithium is beneficial to improving the coulombic efficiency, so that the discharge capacity and the cycle performance are improved.

Description

Preparation method of pre-lithium-intercalated negative electrode, pre-lithium-intercalated negative electrode prepared by preparation method, energy storage device, energy storage system and electric equipment
Technical Field
The invention relates to the field of new energy, in particular to a preparation method of a pre-lithium-intercalated negative electrode, the prepared pre-lithium-intercalated negative electrode, an energy storage device, an energy storage system and electric equipment.
Background
As a green energy storage device, a secondary battery represented by a lithium ion battery realizes storage and discharge by reversible conversion between electric energy and chemical energy, and is widely applied to various fields. The lithium ion battery mainly comprises main parts such as positive and negative electrode active materials, a current collector, an electrolyte ring, a diaphragm and the like. The lithium ion battery realizes the charge and discharge process of the battery (also called as a rocking chair type battery) by means of the back and forth movement (the insertion and extraction process) of lithium ions between a positive electrode and a negative electrode, and particularly, during charging, the lithium ions are extracted from the positive electrode and are inserted into the negative electrode through electrolyte; the discharge process is reversed. Due to the limitation of the theoretical specific capacity of the anode and cathode materials, the energy density of the commercial lithium ion battery is very limited. The negative electrode material mainly adopts modified natural graphite, artificial graphite and the like at present, however, the specific capacity of the graphite electrode is limited (372mAh/g) and almost reaches the limit; meanwhile, the graphite cathode has low compaction density, so that the acquisition of high volume energy density of the battery is greatly limited. Therefore, the research and development of key technologies for more cheap, efficient and low-cost cathode materials are urgent.
Preliminary studies show that a high-capacity and low-cost cheap metal foil is used as a battery cathode, the alloying/dealloying process of metal and lithium ions is utilized to realize the charge-discharge reaction of the battery, and a novel lithium ion battery with high specific capacity and high energy density can be obtained.
In order to fully utilize a metal foil which is cheap, has high capacity and simple preparation process as a battery cathode and solve the problems of low coulombic efficiency and easy pulverization caused by the metal foil as the battery cathode, a method which is usually adopted is to perform porous design on the foil or coat the surface of the foil. For example, PCT/CN2016/081344 and PCT/CN2016/081345 propose that a metal aluminum foil is designed to be porous, and a surface carbon coating method is adopted, so that pulverization of an aluminum negative electrode in the charging and discharging process can be effectively inhibited, and the cycle service life and the charging and discharging rate performance of a battery can be improved. However, the above method requires relatively complicated processes such as laser perforation, electrochemical corrosion, high temperature carbonization, etc., thereby increasing the overall cost of the battery.
In view of the above, the present invention is particularly proposed.
Disclosure of Invention
The invention aims to provide a preparation method of a pre-lithium-embedded negative electrode, which has simple process and low cost, can form an SEI passive film on the surface of a metal material, and avoids the negative electrode from volume expansion and pulverization, thereby improving the stability of the negative electrode, and an alloy formed by pre-lithium-embedded contributes to improving the coulombic efficiency, thereby improving the discharge capacity and the cycle performance.
The second purpose of the invention is to provide the pre-lithium-intercalated negative electrode prepared by the preparation method of the pre-lithium-intercalated negative electrode, and the negative electrode has the advantages of low cost, high stability, low self weight, high energy density, high specific capacity, high coulomb effect and good cycle performance.
The third purpose of the invention is to provide an energy storage device, which comprises the pre-lithium-intercalated cathode prepared by the preparation method of the pre-lithium-intercalated cathode and has the advantages of low device cost, stable structure, high coulombic efficiency, high discharge capacity, high energy density and good cycle performance.
A fourth object of the present invention is to provide an energy storage system, which includes the above energy storage device, and has the advantages of low cost, stable structure, high coulombic efficiency, high specific capacity, high energy density, and good cycle performance.
The fifth purpose of the present invention is to provide an electric device, which includes the energy storage device, and has the advantages of low cost, high specific capacity, high energy density, and good cycle performance, and the electric device has a longer service life when used under the same charging and discharging current and the same environment.
In order to achieve the above purpose of the present invention, the following technical solutions are adopted:
in a first aspect, the present invention provides a method for preparing a pre-lithium-intercalation cathode, providing a half-cell, and charging or discharging the half-cell;
the working electrode of the half cell is made of a metal material, the counter electrode is made of a material capable of providing a lithium source, and the electrolyte is a lithium salt solution containing an additive;
the metal material comprises a metal, an alloy or a metal composite material capable of undergoing an alloying reaction with lithium ions;
the additive includes a substance capable of decomposing and forming an SEI film on the surface of the metal material.
As a further preferable technical solution, the metal is any one of aluminum, tin, magnesium, zinc, copper, iron, nickel, titanium, manganese, antimony, or bismuth;
or, the alloy is an alloy at least comprising any one of aluminum, tin, magnesium, zinc, copper, iron, nickel, titanium, manganese, antimony or bismuth;
or the metal composite material is a composite material at least comprising any one of aluminum, tin, magnesium, zinc, copper, iron, nickel, titanium, manganese, antimony or bismuth;
preferably, the thickness of the metal material is 10 to 1000 μm.
As a further preferred technical solution, the material capable of providing a lithium source comprises metallic lithium or a lithium compound;
preferably, the lithium compound comprises at least one of lithium sulfide, lithium oxide, lithium selenide, lithium fluoride, lithium oxalate, lithium cobaltate, lithium carbonate or lithium iron phosphate;
preferably, the counter electrode is metal lithium, and the half cell with the metal lithium as the counter electrode is discharged;
preferably, the counter electrode is a lithium compound, and the half-cell having the lithium compound as the counter electrode is charged.
As a further preferable technical scheme, the additive comprises L iBOB, L iODFB and L iPO2F2L iDFOP, L iBMB, L idfmmb, L ideffmb, L idfpmb, or L iTFOP;
preferably, the mass fraction of the additive in the electrolyte is 0.1-30%, preferably 8-15%;
preferably, the lithium salt in the electrolyte comprises at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium chloride, lithium carbonate, lithium sulfate, lithium nitrate, lithium fluoride, lithium trifluoromethanesulfonate, lithium bis (trifluoromethylsulfonyl) imide, lithium difluorosulfonimide or lithium perchlorate;
preferably, the concentration of lithium salt in the electrolyte is 0.1-10 mol/L;
preferably, the solvent of the electrolyte includes at least one of esters, sulfones, ethers, nitriles, or olefins;
preferably, the solvent of the electrolyte includes at least one of Propylene Carbonate (PC), Ethylene Carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), Ethyl Methyl Carbonate (EMC), Methyl Formate (MF), Methyl Acetate (MA), N-Dimethylacetamide (DMA), fluoroethylene carbonate (FEC), Methyl Propionate (MP), Ethyl Propionate (EP), Ethyl Acetate (EA), γ -butyrolactone (GB L), Tetrahydrofuran (THF), 2-methyltetrahydrofuran (2MeTHF), 1, 3-dioxolane (DO L), 4-methyl-1, 3-dioxolane (4MeDO L), Dimethoxymethane (DMM), 1, 2-Dimethoxypropane (DMP), triethylene glycol dimethyl ether (DMM), dimethyl sulfone (MSM), dimethyl ether (DME), Ethylene Sulfite (ES), Propylene Sulfite (PS), dimethyl sulfite (DMS), diethyl sulfite (DES), or crown ether (12-crown-4).
As a further preferable technical solution, the current for charging or discharging is 0.01-1mA/cm2The charging or discharging time is 100-1 hour;
preferably, the half-cell further comprises a separator comprising at least one of glass fiber, polyethylene separator, polypropylene separator, or polypropylene/polyethylene/polypropylene separator.
In a second aspect, the invention provides a pre-lithium-intercalated negative electrode prepared by the preparation method of the pre-lithium-intercalated negative electrode.
In a third aspect, the invention provides an energy storage device, which comprises a pre-lithium-intercalated negative electrode prepared by the preparation method of the pre-lithium-intercalated negative electrode.
As a further preferable technical solution, the energy storage device further includes a positive electrode material;
preferably, the energy storage device is a lithium ion battery, and the positive electrode material comprises at least one of lithium manganate, lithium cobaltate, lithium iron phosphate or ternary materials;
preferably, the energy storage device is a lithium ion capacitor, and the positive electrode material comprises at least one of activated carbon, carbon nanotubes, activated carbon fibers, graphene, mesoporous carbon, carbon molecular sieves or carbon foams;
preferably, the energy storage device is a bi-ion battery and the positive electrode material comprises natural graphite and/or expanded graphite.
In a fourth aspect, the invention provides an energy storage system comprising the energy storage device.
In a fifth aspect, the invention provides an electric device, which comprises the energy storage device.
Compared with the prior art, the invention has the beneficial effects that:
according to the preparation method of the pre-embedded lithium negative electrode, a metal material is used as a working electrode, a material capable of providing a lithium source is used as a counter electrode, and a half battery assembled by a lithium salt solution containing an additive and used as an electrolyte is charged or discharged. The working mechanism of the pre-lithium intercalation is as follows: in the process of charging or discharging, an additive in the electrolyte is firstly decomposed, so that an SEI passive film is formed on the surface of the metal material, and in the process of further charging or discharging, lithium ions and the metal material are subjected to alloying reaction through the passive film to form an alloy of the metal material and lithium, so that the process of pre-embedding lithium is completed. The counter electrode is mainly used for providing a lithium source for pre-lithium intercalation; and the working electrode made of metal material is the pre-lithium-embedded negative electrode after the pre-lithium-embedded is finished.
The method has simple process and low cost. The SEI passive film formed in the pre-lithium intercalation process is beneficial to improving the stability of the negative electrode, reducing the volume expansion of the negative electrode generated in the alloying/dealloying process with lithium ions and avoiding the negative electrode from being pulverized, and the alloy formed by pre-lithium intercalation is beneficial to improving the coulombic efficiency and the discharge capacity and the cycle performance. In addition, the negative electrode is made of a metal material pre-embedded with lithium, and the metal material is used as a negative active material and a negative current collector, so that the self weight of the negative electrode can be effectively reduced, and the energy density and specific capacity of the energy storage device are further increased.
The pre-embedded lithium cathode prepared by the preparation method of the pre-embedded lithium cathode has the advantages of low cost, high stability, small volume expansion generated in the alloying/de-alloying process with lithium ions, difficulty in pulverization, high coulomb effect and good cycle performance, and the cathode has the advantage of low self weight, and can further increase the energy density and specific capacity of an energy storage device.
The energy storage device provided by the invention comprises the pre-lithium-intercalated cathode prepared by the preparation method of the pre-lithium-intercalated cathode, so that the energy storage device has the advantages of low cost, stable structure, high coulombic efficiency, high discharge capacity, high energy density and good cycle performance.
The energy storage system provided by the invention comprises the energy storage device, so that the energy storage system at least has the same advantages as the energy storage device, and has the advantages of low cost, stable structure, high coulombic efficiency, high specific capacity, high energy density and good cycle performance.
The electric equipment provided by the invention comprises the energy storage device, so that the electric equipment at least has the same advantages as the energy storage device, has the advantages of low cost, high specific capacity, high energy density and good cycle performance, and has longer service life when used under the same charging and discharging current and the same environment.
Drawings
Fig. 1 is a schematic structural view of a half cell in a method for preparing a pre-lithium intercalation negative electrode according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of an energy storage device according to an embodiment of the invention;
FIG. 3 is a pre-intercalation lithium discharge curve for example 1 and comparative example 1;
FIG. 4(a) is a surface topography of a pre-lithium intercalation negative electrode obtained in comparative example 1;
fig. 4(b) shows the surface morphology of the pre-lithium-intercalated negative electrode obtained in example 1.
Icon: 1-a working electrode; 2-a counter electrode; 3-half cell electrolyte; 5-half cell separator; 6-pre-lithium intercalation negative electrodes; 7-energy storage device electrolyte; 9-energy storage device membrane; 10-positive electrode active material; 11-positive electrode current collector.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer.
It should be noted that:
in the present invention, all the embodiments and preferred methods mentioned herein can be combined with each other to form a new technical solution, if not specifically stated.
In the present invention, all the technical features mentioned herein and preferred features may be combined with each other to form a new technical solution, if not specifically stated.
In the present invention, the percentage (%) or parts means the weight percentage or parts by weight with respect to the composition, if not otherwise specified.
In the present invention, the components referred to or the preferred components thereof may be combined with each other to form a novel embodiment, if not specifically stated.
In the present invention, unless otherwise stated, the numerical range "a-b" represents a shorthand representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, a numerical range of "0.01 to 1" indicates that all real numbers between "0.01 to 1" have been listed herein, and "0.01 to 1" is only a shorthand representation of the combination of these numbers.
The "ranges" disclosed herein may have one or more lower limits and one or more upper limits, respectively, in the form of lower limits and upper limits.
In the present invention, unless otherwise specified, the individual reactions or operation steps may be performed sequentially or may be performed in sequence. Preferably, the reaction processes herein are carried out sequentially.
Unless otherwise defined, technical and scientific terms used herein have the same meaning as is familiar to those skilled in the art. In addition, any methods or materials similar or equivalent to those described herein can also be used in the present invention.
In a first aspect, there is provided in at least one embodiment a method of making a pre-lithium intercalation anode, providing a half-cell, charging or discharging the half-cell;
the working electrode of the half cell is made of a metal material, the counter electrode is made of a material capable of providing a lithium source, and the electrolyte is a lithium salt solution containing an additive;
the metal material comprises a metal, an alloy or a metal composite material capable of undergoing an alloying reaction with lithium ions;
the additive includes a substance capable of decomposing and forming an SEI film on the surface of the metal material.
It should be noted that:
the "metal, alloy or metal composite material capable of undergoing an alloying reaction with lithium ions" refers to a metal capable of undergoing an alloying reaction with lithium ions, an alloy material capable of undergoing an alloying reaction with lithium ions, or a metal composite conductive material capable of undergoing an alloying reaction with lithium ions.
The term "alloy" means a substance having a metallic property which is synthesized from two or more metals and metals or nonmetals by a certain method.
"Metal composite" refers to a metal matrix composite conductive material formed by combining a metal with other non-metallic materials. Typical, but non-limiting, metal composites include graphene-metal composites, carbon fiber-metal composites, or ceramic-metal composites, among others.
The term "material capable of providing a lithium source" refers to a material containing lithium, and the lithium in the material can enter the electrolyte in the form of lithium ions during the charging or discharging process of the half cell, and then can perform an alloying reaction with the working electrode to form an alloy of the metal material and the lithium.
It should be understood that the standard electrode potentials of the different "materials capable of providing a lithium source" are different, and when the standard electrode potential is lower than the working electrode, the pair of electrodes serves as the negative electrode of the half-cell, and the half-cell is discharged to realize pre-intercalation of lithium into the metal material; when the standard electrode potential is higher than the working electrode, the pair of electrodes is used as the positive electrode of the half cell, and the half cell is charged so as to realize the pre-lithium intercalation of the metal material.
The phrase "capable of decomposing and forming an SEI film on the surface of the metal material" means that it is capable of decomposing during the charge or discharge of a half cell and then forming an SEI passivation film on the surface of the metal material.
In the preparation method of the pre-lithium-embedded negative electrode, a metal material is used as a working electrode, a material capable of providing a lithium source is used as a counter electrode, and a half battery assembled by a lithium salt solution containing an additive as an electrolyte is charged or discharged. The working mechanism of the pre-lithium intercalation is as follows: in the process of charging or discharging, an additive in the electrolyte is firstly decomposed, so that an SEI passive film is formed on the surface of the metal material, and in the process of further charging or discharging, lithium ions and the metal material are subjected to alloying reaction through the passive film to form an alloy of the metal material and lithium, so that the process of pre-embedding lithium is completed. The counter electrode is mainly used for providing a lithium source for pre-lithium intercalation; and the working electrode made of metal material is the pre-lithium-embedded negative electrode after the pre-lithium-embedded is finished.
The SEI (solid Electrolyte interface) film is a solid Electrolyte interface film, which is formed in the first discharge process of the energy storage device and is an electrode material and electricityThe SEI film can stably exist in organic solvent, and can effectively prevent solvent molecules from passing through, so as to prevent the solvent molecules from reacting with the electrode material to cause the damage of the electrode material, and L i+But can be freely inserted and extracted through the SEI film without generating adverse effects on the charge and discharge and cycle performance of the battery.
The method has simple process and low cost. The SEI passive film formed in the pre-lithium intercalation process is beneficial to improving the stability of the negative electrode, reducing the volume expansion of the negative electrode generated in the alloying/dealloying process with lithium ions and avoiding the negative electrode from being pulverized, and the alloy formed by pre-lithium intercalation is beneficial to improving the coulombic efficiency of the negative electrode and improving the discharge capacity and the cycle performance. In addition, the negative electrode is made of a metal material pre-embedded with lithium, and the metal material is used as a negative active material and a negative current collector, so that the self weight of the negative electrode can be effectively reduced, and the energy density and specific capacity of the energy storage device are further increased.
In a preferred embodiment, the metal is any one of aluminum, tin, magnesium, zinc, copper, iron, nickel, titanium, manganese, antimony, or bismuth;
or, the alloy is an alloy at least comprising any one of aluminum, tin, magnesium, zinc, copper, iron, nickel, titanium, manganese, antimony or bismuth;
or the metal composite material is a composite material at least comprising any one of aluminum, tin, magnesium, zinc, copper, iron, nickel, titanium, manganese, antimony or bismuth.
Typical but not limiting examples of such alloys are aluminum tin alloy, magnesium zinc alloy, copper iron alloy, nickel titanium alloy, manganese antimony alloy, antimony bismuth alloy, aluminum tin magnesium alloy, zinc copper iron alloy, nickel titanium manganese alloy, manganese antimony bismuth alloy, etc. The metal composite material is typically, but not limited to, an aluminum/graphene composite foil, a tin/graphene composite foil, a magnesium/graphene composite foil, or a zinc/graphene composite foil.
Further, the thickness of the metal material is 10-1000 μm. The thickness of the above-mentioned metal material is typically, but not limited to, 10 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm, 700 μm, 750 μm, 800 μm, 850 μm, 900 μm, 950 μm or 1000 μm.
The metal material is preferably in the form of a foil, and the pre-lithium-embedded negative electrode prepared is preferably in the form of a sheet.
In a preferred embodiment, the material capable of providing a lithium source comprises metallic lithium or a lithium compound. The "lithium compound" refers to a substance composed of lithium and one or more other elements.
Preferably, the lithium compound comprises at least one of lithium sulfide, lithium oxide, lithium selenide, lithium fluoride, lithium oxalate, lithium cobaltate, lithium carbonate or lithium iron phosphate. Typical but non-limiting examples of such lithium compounds are lithium sulfide, lithium oxide, lithium selenide, lithium fluoride, lithium oxalate, lithium cobaltate, lithium carbonate, lithium iron phosphate, a combination of lithium sulfide and lithium oxide, a combination of lithium selenide and lithium fluoride, a combination of lithium oxalate and lithium cobaltate, a combination of lithium carbonate and lithium iron phosphate, a combination of lithium sulfide, lithium oxide and lithium selenide, a combination of lithium fluoride, lithium oxalate and lithium cobaltate, or a combination of lithium cobaltate, lithium carbonate and lithium phosphate, etc.
Preferably, the counter electrode is metallic lithium, and the half-cell with the metallic lithium as the counter electrode is discharged. The standard electrode potential of the metal lithium is lower than that of the working electrode, so that the metal lithium is used as a counter electrode to actually serve as a negative electrode in a half cell, the half cell is discharged, lithium ions in the metal lithium can be dissolved into an electrolyte, and pre-lithium intercalation is carried out on a metal material of the working electrode.
Preferably, the counter electrode is a lithium compound, and the half-cell having the lithium compound as the counter electrode is charged. The standard electrode potential of the lithium compound is higher than that of the working electrode, so that the half cell is actually used as a positive electrode by taking the lithium compound as a counter electrode, the half cell is charged, lithium ions in the lithium compound can be extracted into the electrolyte, and the metal material of the working electrode is pre-intercalated with lithium.
When a lithium compound is used as the counter electrode, the counter electrode includes an electrode material and an electrode current collector, the electrode material includes an electrode active material, a solvent, a conductive agent, a binder, and the like, wherein the electrode active material is the lithium compound.
In a preferred embodiment, the additive comprises L iBOB, L iODFB, L iPO2F2L iDFOP, L iBMB, L iDFMFMB, L iDFEFMB, L iDFPFMB or L iTFOP, L iBOB is lithium dioxalate borate, L iODFB is lithium difluorooxalate borate, L iPO2F2The additive is lithium difluorophosphate, L iDFOP is lithium difluorobis (oxalato) phosphate, L iBMB lithium bis (malonato) borate, L iDFMFMB is lithium difluoro-2-methyl-2-fluoropropanedioate, L iDFEFMB is lithium difluoro-2-ethyl-2-fluoropropanedioate, L iDFPFMB is lithium difluoro-2-propyl-2-fluoropropanedioate, and L iTFOP is lithium tetrafluorooxalato phosphate.
Typical but not limiting additives mentioned above are L iBOB, &lTtT transfer = L "&gTt L &lTt/T &gTt iODFB, &lTtT transfer = L" &gTt L &/T &gTt iPO &2F2L iDFOP, &lTtT transfer = L "&gTtT L &lTtT/T &gTtT ibMB, &lTtT transfer = L" &gTtT L &lTtT/T &gTtT iDFMFMB, &lTtT transfer = L "&gTtT L &lTtT/T gEFEFMB, &tttTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTfOP," (L &/T transfer & "" (L &/T transfer &t & &l & (fTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTtTfOP, "(L/T transfer &2F2And L idfo, L idfb and L idfmmb, L idffemb and L idffemb, L idffemb and L itfo, L iBOB, L idodfb and L iPO2F2A combination of L iDFOP, L idfb and L idfmmb, or a combination of L idefmb, L idfpmb and L iTFOP, or the like.
In a preferred embodiment, the mass fraction of the additive in the electrolyte is between 0.1% and 30%, preferably between 8% and 15%. The above-mentioned mass fraction is typically, but not limited to, 0.1%, 0.5%, 1%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28% or 30%. The thickness of the SEI film can be regulated and controlled by adjusting the mass parts of the additives. When the mass fraction of the additive is 0.1-30%, the thickness of the SEI film is reasonable, the irreversible capacity loss of the negative electrode during the first discharge is reduced, the negative electrode is ensured to have good stability, and the electrochemical performance of the negative electrode is not influenced.
Further, the lithium salt includes at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium chloride, lithium carbonate, lithium sulfate, lithium nitrate, lithium fluoride, lithium trifluoromethanesulfonate, lithium bis (trifluoromethylsulfonyl) imide, lithium difluorosulfonimide, or lithium perchlorate. Typical but non-limiting examples of such lithium salts are lithium hexafluorophosphate, lithium tetrafluoroborate, lithium chloride, lithium carbonate, lithium sulfate, lithium nitrate, lithium fluoride, lithium trifluoromethanesulfonate, lithium bis (trifluoromethylsulfonyl) imide, lithium difluorosulfimide, lithium perchlorate, a combination of lithium hexafluorophosphate and lithium tetrafluoroborate, a combination of lithium chloride and lithium carbonate, a combination of lithium sulfate and lithium nitrate, a combination of lithium fluoride and lithium trifluoromethanesulfonate, a combination of lithium bis (trifluoromethylsulfonyl) imide and lithium difluorosulfimide, a combination of lithium hexafluorophosphate, lithium tetrafluoroborate and lithium chloride, a combination of lithium carbonate, lithium sulfate and lithium nitrate, a combination of lithium fluoride, lithium trifluoromethanesulfonate and lithium bis (trifluoromethylsulfonyl) imide, or a combination of lithium bis (trifluoromethylsulfonyl) imide, lithium difluorosulfimide and lithium perchlorate, and the like.
Further, the concentration of the lithium salt in the electrolyte is 0.1-10 mol/L. the concentration of the lithium salt is typically, but not limited to, 0.1 mol/L, 0.5 mol/L0, 1 mol/L1, 1.5 mol/L2, 2 mol/L3, 2.5 mol/L4, 3 mol/L5, 3.5 mol/L6, 4 mol/L7, 4.5 mol/L8, 5 mol/L9, 5.5 mol/L, 6 mol/L0, 6.5 mol/L1, 7 mol/L, 7.5 mol/L, 8 mol/L, 8.5 mol/L, 9 mol/L, 9.5 mol/L, or 10 mol/L.
Further, the solvent of the electrolyte includes at least one of Propylene Carbonate (PC), Ethylene Carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), Ethyl Methyl Carbonate (EMC), Methyl Formate (MF), Methyl Acetate (MA), N-Dimethylacetamide (DMA), fluoroethylene carbonate (FEC), Methyl Propionate (MP), Ethyl Propionate (EP), Ethyl Acetate (EA), γ -butyrolactone (GB L), Tetrahydrofuran (THF), 2-methyltetrahydrofuran (2MeTHF), 1, 3-dioxolane (DO L), 4-methyl-1, 3-dioxolane (4MeDO L), Dimethoxymethane (DMM), 1, 2-Dimethoxypropane (DMP), triethylene glycol dimethyl ether (DMM), dimethyl sulfone (MSM), dimethyl ether (DME), Ethylene Sulfite (ES), Propylene Sulfite (PS), dimethyl sulfite (DMS), diethyl sulfite (DES), or crown ether (12-crown-4).
Typical but non-limiting examples of such solvents are propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, methyl formate, methyl acetate, N, N-dimethylacetamide, fluoroethylene carbonate, methyl propionate, ethyl acetate, γ -butyrolactone, tetrahydrofuran, 2-methyltetrahydrofuran, 1, 3-dioxolane, 4-methyl-1, 3-dioxolane, dimethoxymethane, 1, 2-dimethoxypropane, triethylene glycol dimethyl ether, dimethyl sulfone, dimethyl ether, ethylene sulfite, propylene sulfite, dimethyl sulfite, diethyl sulfite, crown ether (12-crown-4), a combination of propylene carbonate and ethylene carbonate, a combination of diethyl carbonate and dimethyl carbonate, a combination of ethyl methyl carbonate and methyl formate, a combination of methyl acetate and N, N-dimethylacetamide, a combination of fluoroethylene carbonate and methyl propionate, a combination of ethyl propionate and ethyl acetate, a combination of gamma-butyrolactone and tetrahydrofuran, a combination of 2-methyltetrahydrofuran and 1, 3-dioxolane, a combination of 4-methyl-1, 3-dioxolane and dimethoxymethane, a combination of 1, 2-dimethoxypropane and triethylene glycol dimethyl ether, a combination of dimethyl sulfone and dimethyl ether, a combination of ethylene sulfite and propylene sulfite, a combination of dimethyl sulfite and diethyl sulfite, a combination of propylene carbonate, ethylene carbonate and diethyl carbonate, a combination of dimethyl carbonate, ethyl methyl carbonate and methyl formate, a combination of methyl acetate, N-dimethylacetamide and fluoroethylene carbonate, a combination of methyl propionate, ethyl propionate and ethyl acetate, a combination of γ -butyrolactone, tetrahydrofuran and 2-methyltetrahydrofuran, a combination of 1, 3-dioxolane, 4-methyl-1, 3-dioxolane and dimethoxymethane, a combination of 1, 2-dimethoxypropane, triethylene glycol dimethyl ether and dimethyl sulfone, a combination of dimethyl ether, vinyl sulfite and propylene sulfite, or a combination of dimethyl sulfite, diethyl sulfite and crown ether (12-crown-4), and the like.
In a preferred embodiment, the current for charging or discharging is 0.01-1mA/cm2The charging or discharging time is 100-1 hour.
The current for the above charging or discharging is typically, but not limited to, 0.01mA/cm2、0.1mA/cm2、 0.2mA/cm2、0.3mA/cm2、0.4mA/cm2、0.5mA/cm2、0.6mA/cm2、0.7mA/cm2、 0.8mA/cm2、0.9mA/cm2Or 1mA/cm2. The thickness of the SEI film can be controlled by adjusting the magnitude of the current charged or discharged. When the current for charging or discharging is 0.01-1mA/cm2During the process, the thickness of the SEI film is reasonable, the irreversible capacity loss of the negative electrode during the first discharge is reduced, the negative electrode is guaranteed to have good stability, and meanwhile, the electrochemical performance of the negative electrode cannot be influenced.
The time of the above charge or discharge is typically, but not limited to, 100 hours, 95 hours, 90 hours, 85 hours, 80 hours, 75 hours, 70 hours, 65 hours, 60 hours, 55 hours, 50 hours, 45 hours, 40 hours, 35 hours, 30 hours, 25 hours, 20 hours, 15 hours, 10 hours, 5 hours, or 1 hour. The depth of the pre-lithium intercalation can be regulated and controlled by adjusting the time of charging or discharging. When the charging or discharging time is 100-1 hour, the depth of the pre-embedded lithium in the metal material is more reasonable, the cathode is ensured to have higher coulomb efficiency, and the discharge capacity of the energy storage device is improved.
Further, the preparation method of the pre-lithium-intercalation negative electrode comprises the following steps:
(a) using the metal foil with the required size as a working electrode for standby;
(b) taking metal lithium with required size as a counter electrode for standby;
(c) preparing electrolyte containing an additive for later use;
(d) assembling a working electrode, a counter electrode and electrolyte into a half cell;
(e) discharging the half-cell, and obtaining the pre-lithium-embedded metal foil after the discharging is finished, namely the pre-lithium-embedded negative electrode.
Further, the half cell also includes a separator, including but not limited to fiberglass, polyethylene separator, polypropylene separator, or polypropylene/polyethylene/polypropylene separator, among others.
As shown in fig. 1, a schematic structure of a half-cell is shown, a half-cell electrolyte 3 and a half-cell diaphragm 5 are arranged between a working electrode 1 and a counter electrode 2, the half-cell electrolyte 3 is in contact with the working electrode 1, and the half-cell diaphragm 5 is in contact with the counter electrode 2.
In a second aspect, there is provided in at least one embodiment a pre-lithium intercalation anode prepared using the above-described method of preparing a pre-lithium intercalation anode.
The pre-embedded lithium cathode prepared by the preparation method of the pre-embedded lithium cathode has the advantages of low cost, high stability, small volume expansion generated in the alloying/de-alloying process with lithium ions, difficulty in pulverization, high coulomb effect and good cycle performance, and the cathode has the advantage of low self weight, and can further increase the energy density and specific capacity of an energy storage device.
In a third aspect, in at least one embodiment, an energy storage device is provided that includes a pre-lithium intercalation anode prepared using the above-described method of preparing a pre-lithium intercalation anode. The energy storage device comprises the pre-lithium-embedded cathode prepared by the preparation method of the pre-lithium-embedded cathode, so that the energy storage device has the advantages of low device cost, stable structure, high coulombic efficiency, high discharge capacity, high energy density and good cycle performance.
The energy storage device includes, but is not limited to, a lithium ion battery, a dual ion battery, or a lithium ion capacitor.
The core of the energy storage device is that the energy storage device comprises the pre-lithium-intercalated negative electrode prepared by the preparation method of the pre-lithium-intercalated negative electrode, and in addition, the energy storage device also comprises other components or parts of the existing energy storage device, such as a positive electrode matched with the pre-lithium-intercalated negative electrode, electrolyte, a diaphragm, a shell and the like, which are not particularly limited in the invention; in addition, the preparation method of the energy storage device is only required to be prepared by adopting the existing preparation method, and the invention is not particularly limited to this.
Preferably, the energy storage device is a lithium ion battery, and the positive electrode material includes at least one of lithium manganate, lithium cobaltate, lithium iron phosphate or ternary material. Wherein the ternary material comprises a nickel-cobalt-manganese ternary material and/or a nickel-cobalt-aluminum ternary material.
Preferably, the energy storage device is a lithium ion capacitor, and the positive electrode material includes at least one of activated carbon, carbon nanotubes, activated carbon fibers, graphene, mesoporous carbon, carbon molecular sieves, or carbon foam.
Preferably, the energy storage device is a bi-ion battery and the positive electrode material comprises natural graphite and/or expanded graphite.
Illustratively, the positive electrode current collector includes any one of aluminum, copper, iron, tin, zinc, nickel, titanium, or manganese, or an alloy containing at least any one of the above metal elements, or a metal composite containing at least any one of the above metal elements.
Illustratively, the energy storage device is prepared as follows:
(a) weighing the positive active material, the conductive agent and the binder according to a certain proportion, and then adding a solvent to fully mix to form uniform slurry; wherein, in the slurry, the mass content of the positive active material is 60-95%, the mass content of the conductive agent is 5-30%, and the mass content of the binder is 5-10%;
(b) uniformly coating the slurry on the surface of a positive current collector to form a positive active material layer, and pressing and cutting after complete drying to obtain the positive electrode of the energy storage device with the required size;
(c) preparing conventional electrolyte, and adding an additive with a certain mass fraction;
(d) the pre-embedded lithium cathode prepared by the preparation method of the pre-embedded lithium cathode is used as a cathode, and the pole piece prepared by the smear is used as an anode to assemble an energy storage device.
The additive in the step (c) is a conventional electrolyte additive, and comprises esters, sulfones, ethers, nitriles and olefin organic solvents, and comprises at least one of fluoroethylene carbonate, vinylene carbonate, ethylene carbonate, 1, 3-propane sultone, 1, 4-butane sultone, vinyl sulfate, propylene sulfate, ethylene sulfite, propylene sulfite, dimethyl sulfite, diethyl sulfite, ethylene sulfite, methyl chloroformate or dimethyl sulfoxide.
As shown in fig. 2, the energy storage device includes a pre-lithium-embedded negative electrode 6, an energy storage device diaphragm 9, an energy storage device electrolyte 7, a positive active material 10, and a positive current collector 11, which are sequentially disposed.
In a fourth aspect, in at least one embodiment, an energy storage system is provided, comprising the energy storage device described above. The energy storage system comprises the energy storage device, so that the energy storage system at least has the same advantages as the energy storage device, and has the advantages of low cost, stable structure, high coulombic efficiency, high specific capacity, high energy density and good cycle performance.
The energy storage system refers to an electric power storage system mainly using the energy storage device as an electric power storage source, and includes, but is not limited to, a household energy storage system or a distributed energy storage system. For example, in a household energy storage system, electric power is stored in the above energy storage device serving as an electric power storage source, and the electric power stored in the above energy storage device is consumed as needed to enable use of various devices such as household electronic products.
In a fifth aspect, in at least one embodiment, there is provided a powered device comprising the energy storage device described above. The electric equipment comprises the energy storage device, so that the electric equipment at least has the advantages of being the same as the energy storage device, low in cost, high in specific capacity, high in energy density and good in cycle performance, and the service life of the electric equipment is longer when the electric equipment is used under the same charging and discharging current and the same environment.
The electric equipment includes, but is not limited to, an electronic device, an electric tool, an electric vehicle, and the like. The electronic apparatus is an electronic apparatus that performs various functions (e.g., playing music) using the above-described energy storage device as an operating power source. The power tool is a power tool that uses the above-described energy storage device as a driving power source moving member (e.g., a drill). The electric vehicle is an electric vehicle (including an electric bicycle, an electric automobile) that runs by relying on the above energy storage device as a drive power source, and may be an automobile (including a hybrid automobile) equipped with other drive sources in addition to the above energy storage device.
The present invention will be described in further detail with reference to examples and comparative examples.
Example 1
A preparation method of a pre-lithium-intercalation negative electrode comprises the following steps:
a) taking an aluminum foil with the thickness of 50 mu m, cutting the aluminum foil into a wafer with the diameter of 12mm, cleaning the wafer with acetone and ethanol, drying the wafer, and placing the wafer in a glove box to be used as a working electrode for later use;
b) weighing a certain amount of lithium hexafluorophosphate in a glove box, and adding the lithium hexafluorophosphate into a mixture of ethylene carbonate, dimethyl carbonate and diethyl carbonate (the volume ratio of the ethylene carbonate to the dimethyl carbonate to the diethyl carbonate is 1:1:1) to prepare 1M lithium hexafluorophosphate electrolyte;
c) weighing a certain amount of lithium difluoro (oxalato) borate, stirring until the lithium difluoro (oxalato) borate is completely dissolved, and preparing the electrolyte with the final additive content of 10 wt.%;
d) cutting the glass fiber paper into a wafer with the diameter of 16mm, vacuum-drying at 80 ℃ for 12h, and placing the wafer in a glove box to serve as a diaphragm for later use;
e) in a glove box in argon atmosphere, tightly stacking metal lithium, a diaphragm and a metal aluminum electrode in turn, dripping electrolyte to completely soak the diaphragm, packaging the stacked part into a shell, and pre-embedding lithium by discharging with the current of 0.02mA/cm2And discharging for 15h to obtain the pre-lithium-intercalated metal aluminum electrode, namely the pre-lithium-intercalated negative electrode.
Examples 2 to 13
A method for preparing a lithium pre-intercalation negative electrode is different from that of the embodiment 1 in the mass fraction of lithium difluoro (oxalato) borate in the electrolyte in the embodiments 2 to 13, and other steps and parameters are the same as those in the embodiment 1.
Lithium ion capacitors including the pre-lithium intercalation negative electrodes prepared in examples 1-13 were prepared by a process comprising the steps of:
a) weighing a certain amount of lithium hexafluorophosphate in a glove box, and adding the lithium hexafluorophosphate into a mixture of ethylene carbonate, dimethyl carbonate and diethyl carbonate (the volume ratio of the ethylene carbonate to the dimethyl carbonate to the diethyl carbonate is 1:1:1) to prepare 1M lithium hexafluorophosphate electrolyte;
b) adding 0.8g of Activated Carbon (AC), 0.1g of conductive carbon black and 0.1g of polyvinylidene fluoride into 2m L N-methyl pyrrolidone, fully grinding to obtain uniform slurry, uniformly coating the slurry on the surface of an aluminum foil, carrying out vacuum drying at 80 ℃ for 12 hours, cutting the dried electrode plate into a wafer with the diameter of 10mm, compacting by an oil press (10MPa for 10s), and placing in a glove box to serve as an anode for standby;
c) and (3) tightly stacking the anode, the diaphragm and the cathode in sequence, dripping electrolyte to completely soak the diaphragm, and packaging the stacked part into a shell to finish the assembly of the capacitor.
The lithium ion capacitors are respectively subjected to performance tests by adopting a current density of 0.8A/g, and the test results are shown in Table 1.
Table 1: performance parameter Table for lithium ion capacitor including Pre-lithium Embedded negative electrodes prepared in examples 1-13
Figure BDA0001909152430000191
Examples 14 to 21
A method for preparing a pre-lithium-intercalated negative electrode, which is different from that of example 1 in the types of additives of the electrolytes in examples 14 to 21, and the other steps and parameters thereof are the same as those of example 1.
The lithium pre-intercalated negative electrodes prepared in examples 14 to 21 were prepared into lithium ion capacitors according to the same preparation method as in example 1, and the performance of the lithium ion capacitors was measured by using a current density of 0.8A/g, and the measurement results are shown in table 2.
Table 2: performance parameter Table for lithium ion capacitors including lithium pre-intercalated negative electrodes prepared in examples 14-21
Figure BDA0001909152430000201
Examples 22 to 30
A method for producing a lithium pre-intercalation negative electrode, which is different from example 1 in the kind of the metal material used in examples 22 to 30, and the other steps and parameters thereof were the same as those of example 1.
The lithium pre-intercalated negative electrodes prepared in examples 22 to 30 were prepared into lithium ion capacitors according to the same preparation method as in example 1, and the performance of the lithium ion capacitors was measured by using a current density of 0.8A/g, and the measurement results are shown in table 3.
Table 3: performance parameter Table for lithium ion capacitors including Pre-lithium intercalation anodes prepared in examples 22-30
Figure BDA0001909152430000211
Example 31
Different from the embodiment 1, in the step 5) of the embodiment, the lithium carbonate electrode, the diaphragm and the metal aluminum electrode are tightly stacked in sequence to charge and pre-embed lithium, and the charging current is 0.02mA/cm2The charging time is 15 h; the lithium carbonate electrode comprises an electrode current collector aluminum foil and an electrode material taking lithium carbonate as an active substance; the remaining steps and their parameters were the same as in example 1.
Examples 32 to 38
A method for producing a lithium pre-intercalated negative electrode, which is different from that in example 31, lithium carbonate in example 31 was replaced with lithium sulfide, lithium oxide, lithium selenide, lithium fluoride, lithium oxalate, lithium cobaltate and lithium iron phosphate, respectively, and the remaining steps and parameters thereof were the same as those in example 32.
The lithium pre-intercalated negative electrodes prepared in examples 31 to 38 were prepared into lithium ion capacitors according to the same preparation method as in example 1, and the performance of the lithium ion capacitors was measured by using a current density of 0.8A/g, and the measurement results are shown in table 4.
Table 4: table of Performance parameters for lithium ion capacitors including Pre-lithium intercalation cathodes prepared in examples 31-38
Figure BDA0001909152430000221
A bi-ion battery including a pre-lithium intercalation negative electrode prepared as in examples 1-13, the preparation method comprising the steps of:
a) weighing a certain amount of lithium hexafluorophosphate in a glove box, and adding the lithium hexafluorophosphate into a mixture of ethylene carbonate, dimethyl carbonate and diethyl carbonate (the volume ratio of the ethylene carbonate to the dimethyl carbonate to the diethyl carbonate is 1:1:1) to prepare 1M lithium hexafluorophosphate electrolyte;
b) adding 0.8g of Natural Graphite (NG), 0.1g of conductive carbon black and 0.1g of polyvinylidene fluoride into 2m L N-methyl pyrrolidone, fully grinding to obtain uniform slurry, uniformly coating the slurry on the surface of an aluminum foil, carrying out vacuum drying at 80 ℃ for 12 hours, cutting the dried electrode plate into a wafer with the diameter of 10mm, compacting by an oil press (10MPa for 10s), and placing in a glove box to serve as a positive electrode for later use;
c) and (3) tightly stacking the anode, the diaphragm and the cathode in sequence, dripping electrolyte to completely soak the diaphragm, and packaging the stacked part into a shell to complete the assembly of the dual-ion battery.
The performance of the double-ion battery is tested by adopting the current density of 0.8A/g, and the test results are shown in table 5.
Table 5: table of performance parameters for a Dual ion Battery comprising Pre-intercalated lithium anodes prepared in examples 1-13
Figure BDA0001909152430000231
Figure BDA0001909152430000241
A lithium ion battery including the pre-intercalated lithium negative electrodes prepared in examples 1-13 was prepared by a method including the steps of:
a) weighing a certain amount of lithium hexafluorophosphate in a glove box, and adding the lithium hexafluorophosphate into a mixture of ethylene carbonate, dimethyl carbonate and diethyl carbonate (the volume ratio of the ethylene carbonate to the dimethyl carbonate to the diethyl carbonate is 1:1:1) to prepare 1M lithium hexafluorophosphate electrolyte;
b) adding 0.8g of lithium iron phosphate, 0.1g of conductive carbon black and 0.1g of polyvinylidene fluoride into 2m L N-methyl pyrrolidone, fully grinding to obtain uniform slurry, uniformly coating the slurry on the surface of an aluminum foil, carrying out vacuum drying at 80 ℃ for 12 hours, cutting the dried electrode plate into a wafer with the diameter of 10mm, compacting by an oil press (10MPa for 10s), and placing in a glove box to serve as an anode for standby;
c) and (3) tightly stacking the anode, the diaphragm and the cathode in sequence, dripping electrolyte to completely soak the diaphragm, and packaging the stacked part into a shell to finish the assembly of the lithium ion battery.
The lithium ion batteries are respectively subjected to performance tests by adopting a current density of 0.8A/g, and the test results are shown in Table 6.
Table 6: table of Performance parameters for lithium ion batteries including Pre-lithium intercalation cathodes prepared in examples 1-13
Figure BDA0001909152430000242
Figure BDA0001909152430000251
Comparative example 1
A method of making a pre-lithium intercalation negative electrode, different from example 1, the electrolyte of this comparative example does not contain a lithium difluorooxalato borate additive.
The pre-embedded lithium cathode prepared in the comparative example 1 is prepared into a lithium ion capacitor, the preparation method is the same as that of the example 1, the lithium ion capacitor is subjected to performance test by adopting a current density of 0.8A/g, and through the test, the capacity retention rate of the capacitor is 70%, the coulombic efficiency is 89.2%, the energy density is 150Wh/kg, the specific capacitance is 115F/g after the capacitor is cycled for 500 times, and the performances are lower than those of the example 1.
As shown in fig. 3, which shows the pre-embedded lithium discharge curves of example 1 and comparative example 1, it can be seen from the curves that example 1 contains L iODFB, example 1 has a significant reduction peak at discharge corresponding to decomposition of L iODFB, indicating formation of an aluminum metal surface passivation film, while comparative example 1 does not contain L iODFB, which does not have a decomposition process of L iODFB at discharge.
Fig. 4(a) and 4(b) show the surface morphology of the pre-lithium-intercalated negative electrodes obtained in comparative example 1 and example 1, respectively, and the negative electrode materials in comparative example 1 and example 1 both use 50 μm aluminum foil, and it can be seen that L iODFB is not contained in comparative example 1, the surface particles of the negative electrode are large, whereas example 1 contains L iODFB, the surface particles of the negative electrode are fine and uniform, indicating that a well-structured SEI film is formed.
Comparative example 2
Unlike example 1, the additive in the electrolyte of this comparative example was lithium nitrate, which did not form an SEI film on the surface of the metal material.
The pre-embedded lithium cathode prepared in the comparative example 2 is prepared into a lithium ion capacitor, the preparation method is the same as that of the lithium ion capacitor in the example 1, the lithium ion capacitor is subjected to performance test by adopting a current density of 0.8A/g, and through the test, the capacity retention rate is 63 percent, the coulombic efficiency is 69.1 percent, the energy density is 128Wh/kg, the specific capacitance is 97F/g after the capacitor is cycled for 500 times, and the performances are lower than those of the lithium ion capacitor in the example 1.
Comparative example 3
A preparation method of a pre-lithium-intercalation negative electrode comprises the following steps:
a) taking an aluminum foil with the thickness of 50 mu m, cutting the aluminum foil into a wafer with the diameter of 12mm, cleaning the wafer with acetone and ethanol, drying the wafer, and placing the wafer in a glove box to be used as a working electrode for later use;
b) weighing a certain amount of lithium hexafluorophosphate in a glove box, and adding the lithium hexafluorophosphate into a mixture of ethylene carbonate, dimethyl carbonate and diethyl carbonate (the volume ratio of the ethylene carbonate to the dimethyl carbonate to the diethyl carbonate is 1:1:1) to prepare 1M lithium hexafluorophosphate electrolyte;
c) preparing active material lithium carbonate and additive lithium difluoro oxalate borate (the mass ratio of the active material lithium carbonate to the additive lithium difluoro oxalate borate is 9:1) into slurry, coating the slurry on a current collector aluminum foil, and drying the current collector aluminum foil to be used as a lithium carbonate electrode for later use;
d) cutting the glass fiber paper into a wafer with the diameter of 16mm, vacuum-drying at 80 ℃ for 12h, and placing the wafer in a glove box to serve as a diaphragm for later use;
e) in a glove box in an argon atmosphere, a lithium carbonate electrode, a diaphragm and a metal aluminum electrode are sequentially and tightly stacked, electrolyte is dripped to completely soak the diaphragm, the stacked part is packaged into a shell, and then charging is carried out to embed lithium in advance, and the charged electricityThe flow size is 0.02mA/cm2And charging for 15h to obtain the pre-lithium-intercalated metal aluminum electrode, namely the pre-lithium-intercalated negative electrode.
Unlike example 31, this comparative example added a lithium difluorooxalato borate additive to the counter electrode.
The pre-embedded lithium cathode prepared in the comparative example 3 is prepared into a lithium ion capacitor, the preparation method is the same as that of the example 1, the lithium ion capacitor is subjected to performance test by adopting a current density of 0.8A/g, and through the test, the capacity retention rate of the capacitor is 60 percent, the coulombic efficiency is 61.8 percent, the energy density is 131Wh/kg, the specific capacitance is 99F/g after the capacitor is cycled for 500 times, and the performances are lower than those of the example 32.
While particular embodiments of the present invention have been illustrated and described, it would be obvious that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.

Claims (10)

1. A preparation method of a pre-embedded lithium cathode is characterized in that a half battery is provided, and the half battery is charged or discharged;
the working electrode of the half cell is made of a metal material, the counter electrode is made of a material capable of providing a lithium source, and the electrolyte is a lithium salt solution containing an additive;
the metal material comprises a metal, an alloy or a metal composite material capable of undergoing an alloying reaction with lithium ions;
the additive includes a substance capable of decomposing and forming an SEI film on the surface of the metal material;
the additives include L iBOB, L iODFB, L iPO2F2L iDFOP, L iBMB, L idfmmb, L iddfefmb, L idfpmb, or L iTFOP.
2. The method for preparing a pre-lithium-intercalation negative electrode as claimed in claim 1, wherein the metal is any one of aluminum, tin, magnesium, zinc, copper, iron, nickel, titanium, manganese, antimony or bismuth;
or, the alloy is an alloy at least comprising any one of aluminum, tin, magnesium, zinc, copper, iron, nickel, titanium, manganese, antimony or bismuth;
or the metal composite material is a composite material at least comprising any one of aluminum, tin, magnesium, zinc, copper, iron, nickel, titanium, manganese, antimony or bismuth;
the thickness of the metal material is 10-1000 μm.
3. The method of preparing a pre-lithium intercalation anode of claim 1, wherein the material capable of providing a source of lithium comprises metallic lithium or a compound of lithium;
the lithium compound comprises at least one of lithium sulfide, lithium oxide, lithium selenide, lithium fluoride, lithium oxalate, lithium cobaltate, lithium carbonate or lithium iron phosphate;
the counter electrode is metal lithium, and discharges a half cell taking the metal lithium as the counter electrode;
the counter electrode is a lithium compound, and a half cell using the lithium compound as the counter electrode is charged.
4. The method for preparing the pre-lithium intercalation negative electrode as claimed in claim 1, wherein the additive is present in the electrolyte in an amount of 0.1-30% by mass;
the lithium salt in the electrolyte comprises at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium chloride, lithium carbonate, lithium sulfate, lithium nitrate, lithium fluoride, lithium trifluoromethanesulfonate, lithium bis (trifluoromethylsulfonyl) imide, lithium difluorosulfonyl imide or lithium perchlorate;
in the electrolyte, the concentration of lithium salt is 0.1-10 mol/L;
the solvent of the electrolyte comprises at least one of esters, sulfones, ethers, nitriles or olefins;
the solvent of the electrolyte includes at least one of Propylene Carbonate (PC), Ethylene Carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), Ethyl Methyl Carbonate (EMC), Methyl Formate (MF), Methyl Acetate (MA), N-Dimethylacetamide (DMA), fluoroethylene carbonate (FEC), Methyl Propionate (MP), Ethyl Propionate (EP), Ethyl Acetate (EA), γ -butyrolactone (GB L), Tetrahydrofuran (THF), 2-methyltetrahydrofuran (2MeTHF), 1, 3-dioxolane (DO L), 4-methyl-1, 3-dioxolane (4MeDO L), Dimethoxymethane (DMM), 1, 2-Dimethoxypropane (DMP), triethylene glycol dimethyl ether (DG), dimethylsulfone (MSM), dimethyl ether (DME), Ethylene Sulfite (ES), Propylene Sulfite (PS), dimethyl sulfite (DMS), diethyl sulfite (DES), or crown ether (12-crown-4).
5. The method for producing a pre-lithium intercalation negative electrode as claimed in any of claims 1 to 4, characterized in that the current for charging or discharging is 0.01-1mA/cm2The charging or discharging time is 100-1 hour;
the half-cell further comprises a separator comprising at least one of glass fiber, polyethylene separator, polypropylene separator, or polypropylene/polyethylene/polypropylene separator.
6. A pre-lithium intercalation anode prepared by the method of preparing a pre-lithium intercalation anode of any of claims 1-5.
7. An energy storage device comprising a pre-lithium intercalation cathode prepared by the method of any one of claims 1 to 5.
8. The energy storage device of claim 7, further comprising a positive electrode material;
the energy storage device is a lithium ion battery, and the anode material comprises at least one of lithium manganate, lithium cobaltate, lithium iron phosphate or ternary materials;
the energy storage device is a lithium ion capacitor, and the positive electrode material comprises at least one of active carbon, carbon nano tubes, active carbon fibers, graphene, mesoporous carbon, carbon molecular sieves or carbon foams;
the energy storage device is a bi-ion battery, and the positive electrode material comprises natural graphite and/or expanded graphite.
9. An energy storage system comprising the energy storage device of claim 7 or 8.
10. An electrical consumer, characterized in that it comprises an energy storage device according to claim 7 or 8.
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