CN115000489A - Interface regulation liquid for prelithiation electrode, preparation method and application - Google Patents
Interface regulation liquid for prelithiation electrode, preparation method and application Download PDFInfo
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- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
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- H—ELECTRICITY
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/48—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/48—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte
- H01M10/484—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte for measuring electrolyte level, electrolyte density or electrolyte conductivity
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Abstract
The invention discloses an interface regulating liquid for a prelithiation electrode, a preparation method and application thereof, wherein the interface regulating liquid comprises a solvent and a metal salt; the solvent comprises: one or more of an ether solvent, an ester solvent, a ketone solvent, a hydrocarbon solvent, a nitrile solvent or deionized water; the metal salt includes: one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium bis (oxalato) borate, lithium bis (fluorosulfonate) imide, lithium bis (trifluoromethylsulfonyl) imide, lithium perchlorate, lithium fluoride and lithium chloride; the concentration of the metal salt is 0.001g/mL-10 g/mL; the pre-lithiation electrode is obtained by supplementing lithium to the electrode by using a chemical pre-lithiation solution; modifying the pre-lithiation electrode by using the interface regulating and controlling solution, reacting the metal salt of the interface regulating and controlling solution with the chemical pre-lithiation solution remained on the surface of the pre-lithiation electrode, and generating a solid electrolyte layer containing inorganic lithium salt on the surface of the pre-lithiation electrode; wherein, the content of the inorganic lithium salt is between 5 and 90 percent.
Description
Technical Field
The invention relates to the technical field of lithium battery materials, in particular to interface regulation and control liquid for a pre-lithiation electrode, a preparation method and application.
Background
The lithium ion battery has the advantages of high specific energy, large volume energy density, low self-discharge property, long service life and the like, and is widely applied to the fields of 3C, electric automobiles and the like. In the last 30 years, the research of lithium ion batteries in the aspects of energy density, cost, safety and the like has made a lot of important breakthroughs, and the energy density is close to the limit value of the existing electrode material. In the process of practical application of the lithium ion battery, the first coulomb efficiency of the battery is low because the electrode structure has partial irreversible change and the electrode material is easy to react with the electrolyte to consume active lithium in the electrode material, thereby further influencing the integral energy density of the lithium ion battery.
Prelithiation refers to storing some active lithium in the electrode or material prior to the battery charge-discharge cycle to offset the first cycle irreversible lithium loss, and prelithiation technology has become an important process to improve the first cycle efficiency and energy density of the battery. The prelithiation methods that have been reported so far include prelithiation for electrode materials and prelithiation for electrode sheets. Specifically included are doped prelithiation, contact prelithiation, electrochemical prelithiation, and chemical prelithiation. The doped pre-lithiation refers to mixing metal lithium or other materials with higher lithium storage capacity with electrode materials to obtain composite electrode materials or electrode plates; the contact pre-lithiation means that metal lithium is directly contacted with a positive electrode/negative electrode material or an electrode plate to realize the pre-lithiation of the positive electrode/negative electrode; the electrochemical prelithiation refers to that a certain amount of lithium ions are inserted into a positive electrode/negative electrode material or an electrode plate in advance through an electrochemical method; the chemical pre-lithiation means that a solution rich in lithium ions is used for soaking a positive electrode/negative electrode material or an electrode plate, so that a certain amount of additional active lithium is embedded into the positive electrode/negative electrode or the electrode plate to achieve the effect of lithium supplement. The electrode material or electrode plate after the pre-lithiation treatment is sensitive to air due to the high active lithium content, and is easy to react with oxygen, water, carbon dioxide and the like in the air to be polluted or inactivated, so that the experimental production operation and the electrochemical performance are not facilitated.
At present, the lithium content of an electrode material or a pole piece is only increased in the pre-lithiation process, but the interface property of the material or the pole piece is less regulated and controlled in the process, and the electrochemical performance and the safety performance of the battery are seriously influenced by the interface property of the electrode material or the pole piece. The active material of the electrode is easy to react with the electrolyte in the circulation process, a solid electrolyte layer is formed on the surface of the electrode, and the charge transfer and ion transmission at the interface are influenced, so that the electrochemical performance of the battery is influenced. The boundary layer formed by the electrochemical process cannot be accurately regulated and controlled; and the interface property of the material or the electrode can be artificially and controllably adjusted by forming a stable functional interface layer on the surface of the pole piece in advance through a chemical or electrochemical process. The existing manual interface regulation is only aimed at the original electrode material or electrode slice, and the interface of the prelithiation electrode material or electrode slice is regulated. For the electrode material or electrode plate after the pre-lithiation treatment, because the electrochemical activity is higher, the regulation and control of the solid electrolyte layer can be realized more easily, if a stable interface layer can be formed on the surface of the electrode plate preferentially by a surface treatment method, the circulation effect of the electrode plate can be improved, and the uncontrollable electrochemical reaction between the electrode material inside the battery and the electrolyte can be avoided.
Patent CN113193174A provides an interface pretreatment liquid for a silica prelithiation negative electrode and a preparation method and application thereof, a treated pole piece is a lithium supplement pole piece obtained by directly arranging a layer of lithium metal on the surface of a negative electrode diaphragm, solute adopted by an interface regulation liquid is lithium sulfide, aluminum iodide, aluminum bromide, lithium nitrate or copper nitride, the solute directly reacts with metal lithium on the lithium supplement pole piece, and the generated product can effectively inhibit growth of lithium dendrite and side reaction, so that a Solid Electrolyte Interface (SEI) formed on the surface of the prelithiation negative electrode is more stable. However, the interface regulation liquid in the patent directly reacts with the metal lithium on the lithium-supplement pole piece, so that active lithium in the negative pole membrane is consumed, the lithium-supplement effect is weakened, the energy density of the battery is influenced, and the aim of pre-lithiation cannot be completely fulfilled.
Disclosure of Invention
The embodiment of the invention provides interface regulation liquid for a pre-lithiation electrode, a preparation method and application, aiming at the electrode of chemical pre-lithiation, the interface of the pre-lithiation electrode is regulated and controlled by using the interface regulating and controlling liquid, the metal salt of the interface regulating and controlling liquid reacts with the chemical pre-lithiation solution remained on the surface of the pre-lithiation electrode, the solid electrolyte layer containing inorganic lithium salt is formed on the surface of the prelithiation electrode, which not only can effectively maintain the lithium supplementing effect of prelithiation on the electrode, but also can regulate and control the interface components of the electrode, the content of the generated inorganic lithium salt is higher than that of the inorganic lithium salt generated by the electrochemical reaction between the electrode and the electrolyte, so that the lithium secondary battery has good mechanical property and electrochemical stability, can effectively inhibit the growth of lithium dendrites and the occurrence of side reactions, avoids the uncontrollable electrochemical reaction between the electrode material inside the battery and the electrolyte, and is more favorable for improving the cycle performance of the battery. Meanwhile, the prelithiation electrode treated by the interface regulation and control liquid has stability to air.
In a first aspect, the embodiment of the invention provides an interface regulation liquid for a pre-lithiation electrode, which includes a solvent and a metal salt;
the solvent comprises: one or more of an ether solvent, an ester solvent, a ketone solvent, a hydrocarbon solvent, a nitrile solvent or deionized water;
the metal salt includes: one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium bis (oxalato) borate, lithium bis (fluorosulfonate) imide, lithium bis (trifluoromethylsulfonyl) imide, lithium perchlorate, lithium fluoride and lithium chloride; the concentration of the metal salt is 0.001g/mL-10 g/mL;
the pre-lithiation electrode is obtained by supplementing lithium to the electrode by using a chemical pre-lithiation solution;
the interface regulating and controlling liquid is used for modifying the pre-lithiation electrode, the metal salt of the interface regulating and controlling liquid reacts with the chemical pre-lithiation solution remained on the surface of the pre-lithiation electrode, and a solid electrolyte layer containing inorganic lithium salt is generated on the surface of the pre-lithiation electrode; wherein, the content of the inorganic lithium salt is between 5 and 90 percent.
Preferably, the content of the inorganic lithium salt is between 40% and 90%;
the solvent specifically comprises: one or more of methyl propyl ether, methyl butyl ether, methyl amyl ether, ethyl propyl ether, ethyl butyl ether, ethyl amyl ether, propyl butyl ether, propyl amyl ether, tetrahydrofuran, methyl tetrahydrofuran, dimethyl tetrahydrofuran, ethyl tetrahydrofuran, diethyl tetrahydrofuran, phenyl tetrahydrofuran, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate, diphenyl carbonate, dibutyl carbonate, butylene carbonate, ethyl methyl carbonate, fluoroethylene carbonate, trimethylene carbonate, ethylene chlorocarbonate, vinylene carbonate, or deionized water;
the chemical pre-lithiation solution comprises one or more of a biphenyl lithium-dimethyl tetrahydrofuran solution, a biphenyl lithium-ethylene glycol dimethyl ether solution, a tetramethyl biphenyl lithium-dimethyl tetrahydrofuran solution, a tetramethyl biphenyl lithium-ethylene glycol dimethyl ether solution, a naphthalene lithium-dimethyl tetrahydrofuran solution, a naphthalene lithium-ethylene glycol dimethyl ether solution or a liquid ammonia-lithium solution.
Preferably, the interface regulating liquid further comprises a conductive additive; the conductive additive specifically includes: one or more of carbon black, acetylene black, ketjen black, carbon nanotubes, graphene oxide, carbon fibers and carbon quantum dots;
the interface regulating liquid also comprises a binder; the binder specifically includes: one or more of polyvinylidene fluoride, carboxymethyl cellulose, polytetrafluoroethylene, polyacrylic acid, styrene butadiene rubber, polyvinyl alcohol, polybutyl acrylate and polyacrylonitrile;
the interface regulating liquid also comprises functional filler; the functional filler specifically comprises: one or more of boron nitride, aluminum nitride, silicon carbide, magnesium oxide, beryllium oxide, aluminum oxide, zinc oxide, silicon oxide, gold powder, silver powder, copper powder, nickel powder and aluminum powder.
Preferably, the active material of the prelithiated electrode comprises: lithium iron phosphate, lithium cobaltate, lithium nickelate, lithium manganate, nickel cobalt manganese ternary material, nickel cobalt aluminum ternary material, lithium-rich ternary material, lithium nickel manganese oxide, copper fluoride, cobalt fluoride, cobaltous fluoride, ferric fluoride, ferrous fluoride, manganese fluoride, nickel fluoride, zinc fluoride, niobium fluoride, molybdenum chloride, ferric chloride, ferroferric oxide, vanadium pentoxide, nickel sulfide, cobalt sulfide, silicon sulfide, tetraphosphorus heptasulfide, phosphorus pentasulfide, copper oxide, strontium oxide, cobalt oxide, ferric oxide, manganese dioxide, molybdenum trioxide, lithium titanate, lithium vanadate, silicon carbon composite material, silicon monoxide carbon composite material, silicon oxide, silicon dioxide, natural graphite, artificial graphite, graphene, carbon nanotubes, and carbon nanofibers.
In a second aspect, an embodiment of the present invention provides a preparation method of the interface control solution for a prelithiation electrode according to the first aspect, where the preparation method includes:
mixing a solvent and a metal salt according to a proportion to obtain a metal salt solution;
under the inert atmosphere, the ambient temperature is between-10 ℃ and 100 ℃, and the metal salt solution is stirred and mixed uniformly by magnetic force to obtain interface regulating and controlling liquid for the pre-lithiation electrode;
the solvent comprises: one or more of an ether solvent, an ester solvent, a ketone solvent, a hydrocarbon solvent, a nitrile solvent or deionized water;
the metal salt includes: one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium bis (oxalato) borate, lithium bis (fluorosulfonate) imide, lithium bis (trifluoromethylsulfonyl) imide, lithium perchlorate, lithium fluoride and lithium chloride; the concentration of the metal salt is 0.001g/mL-10 g/mL;
the pre-lithiation electrode is obtained by supplementing lithium to the electrode by using a chemical pre-lithiation solution;
the interface regulating and controlling liquid is used for modifying the pre-lithiation electrode, the metal salt of the interface regulating and controlling liquid reacts with the chemical pre-lithiation solution remained on the surface of the pre-lithiation electrode, and a solid electrolyte layer containing inorganic lithium salt is generated on the surface of the pre-lithiation electrode; wherein, the content of the inorganic lithium salt is between 5 and 90 percent.
Preferably, the content of the inorganic lithium salt is between 40% and 90%;
the solvent specifically comprises: one or more of methyl propyl ether, methyl butyl ether, methyl pentyl ether, ethyl propyl ether, ethyl butyl ether, ethyl pentyl ether, propyl butyl ether, propyl pentyl ether, tetrahydrofuran, methyl tetrahydrofuran, dimethyl tetrahydrofuran, ethyl tetrahydrofuran, diethyl tetrahydrofuran, phenyl tetrahydrofuran, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate, diphenyl carbonate, dibutyl carbonate, butylene carbonate, ethyl methyl carbonate, fluoroethylene carbonate, trimethylene carbonate, ethylene chlorocarbonate, vinylene carbonate, or deionized water;
the chemical pre-lithiation solution comprises one or more of a biphenyl lithium-dimethyl tetrahydrofuran solution, a biphenyl lithium-ethylene glycol dimethyl ether solution, a tetramethyl biphenyl lithium-dimethyl tetrahydrofuran solution, a tetramethyl biphenyl lithium-ethylene glycol dimethyl ether solution, a naphthalene lithium-dimethyl tetrahydrofuran solution, a naphthalene lithium-ethylene glycol dimethyl ether solution or a liquid ammonia-lithium solution;
the interface regulating liquid also comprises a conductive additive; the conductive additive specifically includes: one or more of carbon black, acetylene black, ketjen black, carbon nanotubes, graphene oxide, carbon fibers and carbon quantum dots;
the interface regulating liquid also comprises a binder; the binder specifically comprises: one or more of polyvinylidene fluoride, carboxymethyl cellulose, polytetrafluoroethylene, polyacrylic acid, styrene butadiene rubber, polyvinyl alcohol, polybutyl acrylate and polyacrylonitrile;
the interface regulating liquid also comprises functional filler; the functional filler specifically comprises: one or more of boron nitride, aluminum nitride, silicon carbide, magnesium oxide, beryllium oxide, aluminum oxide, zinc oxide, silicon oxide, gold powder, silver powder, copper powder, nickel powder and aluminum powder.
Preferably, the magnetic stirring speed is between 50rpm and 2000rpm, and the magnetic stirring time is between 1 second and 48 hours.
In a third aspect, an embodiment of the present invention provides an interface regulation method for a prelithiation electrode, where the interface regulation method includes: contacting the prelithiation electrode with the interface control liquid described above in the first aspect in an inert atmosphere;
naturally airing or drying the pre-lithiation electrode contacted with the interface regulation and control solution to obtain a pre-lithiation electrode after interface regulation and control;
the interface-regulated pre-lithiated electrode has stability to air.
Preferably, the contact mode is soaking, standing and contacting; the soaking, standing and contacting is to carry out contact reaction at the temperature of-40-200 ℃, and the contact reaction time is between 1 second and 72 hours;
the drying temperature is between-10 ℃ and 300 ℃;
the active material of the prelithiated electrode includes: lithium iron phosphate, lithium cobaltate, lithium nickelate, lithium manganate, ternary nickel cobalt manganese material, ternary nickel cobalt aluminum material, ternary lithium-rich material, lithium nickel manganese oxide, copper fluoride, cobalt fluoride, cobaltous fluoride, ferric fluoride, ferrous fluoride, manganese fluoride, nickel fluoride, zinc fluoride, niobium fluoride, molybdenum chloride, ferric chloride, ferroferric oxide, vanadium pentoxide, nickel sulfide, cobalt sulfide, silicon sulfide, tetraphosphorus heptasulfide, phosphorus pentasulfide, copper oxide, strontium oxide, cobalt oxide, ferric oxide, manganese dioxide, molybdenum trioxide, lithium titanate, lithium vanadate, silicon carbon composite material, silicon monoxide carbon composite material, silicon oxide, silicon dioxide, natural graphite, artificial graphite, graphene, carbon nanotubes, carbon nanofibers.
In a fourth aspect, an embodiment of the present invention provides a lithium battery, where the lithium battery includes the interface-conditioned pre-lithiated electrode described in the third aspect.
The embodiment of the invention provides interface regulating liquid for a pre-lithiation electrode, aiming at the electrode of chemical pre-lithiation, the interface of the pre-lithiation electrode is regulated and controlled by using the interface regulating and controlling liquid, the metal salt of the interface regulating and controlling liquid reacts with the chemical pre-lithiation solution remained on the surface of the pre-lithiation electrode, the solid electrolyte layer containing inorganic lithium salt is formed on the surface of the prelithiation electrode, which not only can effectively maintain the lithium supplementing effect of prelithiation on the electrode, but also can regulate and control the interface components of the electrode, the content of the generated inorganic lithium salt is higher than that of the inorganic lithium salt generated by the electrochemical reaction between the electrode and the electrolyte, so that the lithium secondary battery has good mechanical property and electrochemical stability, can effectively inhibit the growth of lithium dendrites and the occurrence of side reactions, avoids the uncontrollable electrochemical reaction between the electrode material inside the battery and the electrolyte, and is more favorable for improving the cycle performance of the battery.
The prelithiation electrode plate after interface regulation and control has good stability in air, is suitable for the existing lithium ion battery processing technology, and provides possibility for prelithiation work of lithium ion battery electrode materials and development of high-energy density batteries. And the stability of the prelithiation pole piece in the air can be improved by regulating and controlling the components of the electrode interface layer, so that the prelithiation technology is suitable for the current battery production process and is easier to popularize. The interface regulation and control method for the pre-lithiation electrode by using the interface regulation and control solution has the advantages of simple operation, simple and easily obtained raw materials, high safety and strong applicability, has important significance for the application of the pre-lithiation electrode slice and the improvement of the electrochemical performance of the battery, and has wide prospect and use value.
Drawings
The technical solutions of the embodiments of the present invention are further described in detail with reference to the accompanying drawings and embodiments.
FIG. 1 is a flow chart of a method for preparing an interface control solution according to an embodiment of the present invention;
fig. 2 is a flow chart of an interface regulation method of a prelithiation electrode according to an embodiment of the present invention;
fig. 3 is an X-ray diffraction pattern (XRD) of the interface-modulated prelithiated electrode provided in examples 1-8 of the present invention;
fig. 4 is a charge-discharge curve diagram of a battery prepared by adjusting the interface of a pre-lithiated graphite electrode provided in examples 1 to 4 of the present invention;
fig. 5 is a coulombic efficiency graph of a battery prepared by electrode conditioning of a pre-lithiated graphite electrode interface provided in examples 1 to 4 of the present invention;
fig. 6 is a charge-discharge curve diagram of a battery prepared by adjusting the interface of a pre-lithiated graphite electrode provided in examples 5 to 8 of the present invention;
fig. 7 is a coulombic efficiency graph of a battery prepared by electrode conditioning of a pre-lithiated graphite electrode interface, provided in examples 5 to 8 of the present invention;
fig. 8 is an XRD pattern of a graphite electrode of comparative example 1 and a pre-lithiated graphite electrode of comparative example 2 without interface modulation according to the present invention;
FIG. 9 is a graph showing the charge and discharge curves for cells made with comparative example 1 graphite electrode and comparative example 2 pre-lithiated graphite electrode without interfacial regulation according to the present invention;
fig. 10 is a graph of coulombic efficiency for cells made with the comparative example 1 graphite electrode of the invention and the comparative example 2 pre-lithiated graphite electrode without interfacial modulation.
Detailed Description
The invention is described in further detail below with reference to the figures and specific examples, but it should be understood that these examples are for the purpose of illustration only and are not to be construed as limiting the invention in any way, i.e., not as limiting the scope of the invention.
The embodiment of the invention provides an interface regulating liquid for a pre-lithiation electrode, which comprises a solvent and metal salt; the pre-lithiation electrode is obtained by supplementing lithium to the electrode by using a chemical pre-lithiation solution;
modifying the pre-lithiation electrode by using the interface regulating and controlling solution, and reacting the metal salt of the interface regulating and controlling solution with the chemical pre-lithiation solution remained on the surface of the pre-lithiation electrode to form an inorganic lithium salt-containing solid electrolyte layer on the surface of the pre-lithiation electrode; wherein the inorganic lithium salt mainly comprises Li 2 CO 3 And LiF, Li 2 CO 3 The diffusion rate of lithium ions can be increased, and LiF can inhibit the formation of lithium dendrites.
The content range of the inorganic lithium salt generated by the metal salt of the interface regulating solution and the chemical pre-lithiation solution remained on the surface of the pre-lithiation electrode in the embodiment of the invention is between 5% and 90%, preferably between 40% and 90%, and is higher than the content of the inorganic lithium salt generated by the electrochemical reaction between a common electrode and an electrolyte. This is because, compared to the slow ion transport process of the battery during the charging and discharging process, the metal salt in the interface control solution of the present invention reacts with the chemical prelithiation solution remaining on the surface of the prelithiation electrode more rapidly and more fully, which is more conducive to the formation of an inorganic lithium salt component with higher stability.
The invention improves the content of inorganic lithium salt in an electrolyte layer through an interface regulating liquid so as to reduce the proportion of organic lithium salt, fully exerts the function of inorganic lithium salt and improves the stability of a solid electrolyte layer.
Therefore, the inorganic lithium salt generated by the reaction of the interface regulating liquid and the chemical prelithiation solution remained on the surface of the prelithiation electrode has good mechanical property and electrochemical property, can effectively inhibit the growth of lithium dendrite and the occurrence of side reaction, and enables an SEI film formed on the surface of the prelithiation negative electrode to be more stable.
Wherein, the solvent of the interface regulating liquid comprises: one or more of an ether solvent, an ester solvent, a ketone solvent, a hydrocarbon solvent, a nitrile solvent and water; the solvent specifically comprises: one or more of methyl propyl ether, methyl butyl ether, methyl amyl ether, ethyl propyl ether, ethyl butyl ether, ethyl amyl ether, propyl butyl ether, propyl amyl ether, tetrahydrofuran, methyl tetrahydrofuran, dimethyl tetrahydrofuran, ethyl tetrahydrofuran, diethyl tetrahydrofuran, phenyl tetrahydrofuran, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate, diphenyl carbonate, dibutyl carbonate, butylene carbonate, ethyl methyl carbonate, fluoroethylene carbonate, trimethylene carbonate, ethylene chlorocarbonate, vinylene carbonate, and deionized water;
the metal salt includes: one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium bis (oxalato) borate, lithium bis (fluorosulfonate) imide, lithium bis (trifluoromethylsulfonyl) imide, lithium perchlorate, lithium fluoride and lithium chloride; the concentration of the metal salt is 0.001g/mL-10 g/mL;
the electrode is subjected to chemical prelithiation by using a prelithiation solution comprising: one or more of a biphenyl lithium-dimethyl tetrahydrofuran solution, a biphenyl lithium-ethylene glycol dimethyl ether solution, a tetramethyl biphenyl lithium-dimethyl tetrahydrofuran solution, a tetramethyl biphenyl lithium-ethylene glycol dimethyl ether solution, a naphthalene lithium-dimethyl tetrahydrofuran solution, a naphthalene lithium-ethylene glycol dimethyl ether solution and a liquid ammonia-lithium solution.
In an optional scheme, the interface regulating liquid can further comprise a conductive additive, a binder and a functional filler;
wherein the conductive additive specifically comprises: one or more of carbon black, acetylene black, ketjen black, carbon nanotubes, graphene oxide, carbon fibers and carbon quantum dots; the concentration of the conductive additive is 0-10 g/mL;
the adhesive specifically comprises: one or more of polyvinylidene fluoride, carboxymethyl cellulose, polytetrafluoroethylene, polyacrylic acid, styrene butadiene rubber, polyvinyl alcohol, polybutyl acrylate and polyacrylonitrile; the concentration of the binder is 0-10 g/mL;
the functional filler specifically includes: one or more of boron nitride, aluminum nitride, silicon carbide, magnesium oxide, beryllium oxide, aluminum oxide, zinc oxide, silicon oxide, gold powder, silver powder, copper powder, nickel powder and aluminum powder; the concentration of the functional filler is 0-10 g/mL. The functional filler can play a role in inflaming retarding and improving the heat conduction efficiency of the electrode interface, can improve the safety performance of the battery and reduce the risk of thermal failure.
An embodiment of the present invention provides a preparation method of the interface control solution for a prelithiation electrode in the first aspect, as shown in fig. 1, the preparation method includes:
wherein, the solvent comprises: one or more of an ether solvent, an ester solvent, a ketone solvent, a hydrocarbon solvent, a nitrile solvent or deionized water; the method specifically comprises the following steps: one or more of methyl propyl ether, methyl butyl ether, methyl amyl ether, ethyl propyl ether, ethyl butyl ether, ethyl amyl ether, propyl butyl ether, propyl amyl ether, tetrahydrofuran, methyl tetrahydrofuran, dimethyl tetrahydrofuran, ethyl tetrahydrofuran, diethyl tetrahydrofuran, phenyl tetrahydrofuran, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate, diphenyl carbonate, dibutyl carbonate, butylene carbonate, ethyl methyl carbonate, fluoroethylene carbonate, trimethylene carbonate, ethylene chlorocarbonate, vinylene carbonate, or deionized water;
the metal salt includes: one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium bis (oxalato) borate, lithium bis (fluorosulfonate) imide, lithium bis (trifluoromethylsulfonyl) imide, lithium perchlorate, lithium fluoride and lithium chloride; the concentration of the metal salt is 0.001g/mL-10 g/mL;
in an optional scheme, the interface regulating and controlling liquid further comprises a conductive additive; the conductive additive specifically includes: one or more of carbon black, acetylene black, ketjen black, carbon nanotubes, graphene oxide, carbon fibers and carbon quantum dots; the concentration of the conductive additive is 0-10 g/mL;
the interface regulating liquid also comprises a binder; the binder specifically includes: one or more of polyvinylidene fluoride, carboxymethyl cellulose, polytetrafluoroethylene, polyacrylic acid, styrene butadiene rubber, polyvinyl alcohol, polybutyl acrylate and polyacrylonitrile; the concentration of the conductive additive is 0-10 g/mL;
the interface regulating liquid also comprises functional filler; the functional filler specifically includes: one or more of boron nitride, aluminum nitride, silicon carbide, magnesium oxide, beryllium oxide, aluminum oxide, zinc oxide, silicon oxide, gold powder, silver powder, copper powder, nickel powder and aluminum powder; the concentration of the functional filler is 0-10 g/mL; the functional filler has the functions of inflaming retarding and improving the heat conduction efficiency of the electrode interface, can improve the safety performance of the battery and reduce the risk of thermal failure.
wherein the magnetic stirring speed is between 50rpm and 2000rpm, and the magnetic stirring time is between 1 second and 48 hours;
the pre-lithiation electrode is obtained by supplementing lithium to the electrode by using a chemical pre-lithiation solution; the chemical prelithiation solution includes: one or more of a biphenyl lithium-dimethyl tetrahydrofuran solution, a biphenyl lithium-ethylene glycol dimethyl ether solution, a tetramethyl biphenyl lithium-dimethyl tetrahydrofuran solution, a tetramethyl biphenyl lithium-ethylene glycol dimethyl ether solution, a naphthalene lithium-dimethyl tetrahydrofuran solution, a naphthalene lithium-ethylene glycol dimethyl ether solution and a liquid ammonia-lithium solution.
The embodiment of the invention provides an interface regulation and control method of a pre-lithiation electrode, which comprises the following steps of:
wherein the contact mode is soaking, standing and contacting; the soaking standing contact is to carry out contact reaction at the temperature of-40-200 ℃, the contact reaction time is between 1 second and 72 hours, in the process of the contact reaction, metal salt in the interface regulating and controlling liquid reacts with the chemical pre-lithiation solution remained on the surface of the pre-lithiation electrode, and a solid electrolyte layer containing inorganic lithium salt is formed on the surface of the pre-lithiation electrode; wherein, the content of the inorganic lithium salt is higher than that of the inorganic lithium salt generated by the electrochemical reaction between the electrode and the electrolyte, and the content of the inorganic lithium salt is between 5 and 90 percent, preferably between 40 and 90 percent.
wherein, the drying temperature is between-10 ℃ and 300 ℃;
the interface regulating solution provided by the embodiment of the invention can be applied to various types of prelithiation electrodes, and the active materials of the prelithiation electrodes comprise: one or more of lithium iron phosphate, lithium cobaltate, lithium nickelate, lithium manganate, nickel cobalt manganese ternary material, nickel cobalt aluminum ternary material, lithium-rich ternary material, lithium nickel manganese oxide, copper fluoride, cobalt fluoride, cobaltous fluoride, ferric fluoride, ferrous fluoride, manganese fluoride, nickel fluoride, zinc fluoride, niobium fluoride, molybdenum chloride, ferric chloride, ferroferric oxide, vanadium pentoxide, nickel sulfide, cobalt sulfide, silicon sulfide, tetraphosphorus heptasulfide, phosphorus pentasulfide, copper oxide, strontium oxide, cobalt oxide, ferric oxide, manganese dioxide, molybdenum trioxide, lithium titanate, lithium vanadate, silicon-carbon composite material, silicon monoxide-carbon composite material, silicon oxide, silicon dioxide, natural graphite, artificial graphite, graphene, carbon nanotubes and carbon nanofibers;
the prelithiation electrode after interface regulation has stability to air.
The embodiment of the invention provides a lithium battery, which comprises the pre-lithiated electrode treated by the interface regulating and controlling liquid.
In order to better understand the technical scheme provided by the invention, the preparation method, the application and the performance test of the interface regulation liquid are respectively described in the following by using a plurality of specific examples.
Example 1
The embodiment provides a preparation process of an interface regulating liquid and an interface regulating method of a prelithiation electrode, which comprises the following steps:
preparing a pre-lithiated pole piece: pre-lithiating a graphite electrode plate, selecting 1mol/L diphenyl lithium-dimethyl tetrahydrofuran solution as a pre-lithiation reagent, and carrying out contact reaction on a natural graphite electrode plate and the pre-lithiation solution for 10 minutes to obtain the pre-lithiated graphite electrode plate, wherein the open-circuit voltage of the pre-lithiated graphite electrode plate is 0.13V-0.14V.
The preparation process of the interface regulating liquid comprises the following steps:
1) lithium hexafluorophosphate was dissolved in dimethyl carbonate and ethylene carbonate (volume ratio 1: 1) to obtain a solution of a lithium salt at a concentration of 1 g/mL.
2) And (3) under the argon atmosphere, stirring and mixing the solution uniformly by magnetic force at room temperature to obtain the interface regulating and controlling solution for the pre-lithiation electrode. Wherein the magnetic stirring speed is 1000rpm, and the stirring time is 1 hour.
The interface regulation method of the prelithiation electrode comprises the following steps:
1) and (3) soaking, standing and contacting the pre-lithiated graphite electrode plate and the prepared interface regulating and controlling solution at room temperature in an argon atmosphere for 10 minutes.
2) And taking out the pre-lithiated graphite electrode slice which is in contact with the interface regulating and controlling solution, and drying in vacuum at the temperature of 60 ℃ to obtain the pre-lithiated electrode after interface regulation and control.
The pre-lithiated electrode prepared in this example after interface adjustment is subjected to XRD testing, and a test picture is shown in fig. 3.
The interface-conditioned pre-lithiated electrodes prepared in this example were assembled into button half cells for electrochemical testing: the interface-regulated pre-lithiation electrode is used as a positive electrode, metal lithium is used as a battery negative electrode, and an electrolyte is LiPF 6 Assembling the button type half cell with a mixed solution of ethylene carbonate/dimethyl carbonate (EC/DMC); the constant-current charge-discharge mode test is carried out by using a charge-discharge instrument, the discharge cut-off voltage is 0.005V, the charge cut-off voltage is 3V, the first week of charge-discharge test is carried out at the current density of 0.05C, the second week and later of discharge test are carried out at the current density of 0.2C, the test charge-discharge curve chart is shown in figure 4, and the coulombic efficiency curve chart is shown in figure 5.
Example 2
The embodiment provides a preparation process of an interface regulation liquid and an interface regulation method of a prelithiation electrode, which comprises the following steps:
the procedure for making the prelithiated pole pieces was the same as in example 1.
The preparation process of the interface regulating liquid comprises the following steps:
1) dissolving lithium bis (fluorosulfonate) imide salt in dimethyl carbonate and ethylene carbonate (volume ratio of 1: 2) to obtain a solution of a lithium salt having a concentration of 5 g/mL.
2) And (3) under the argon atmosphere, uniformly mixing the solution at room temperature by magnetic stirring to obtain the interface regulating solution for the pre-lithiation electrode. Wherein the magnetic stirring speed is 2000rpm, and the magnetic stirring time is 0.5 hour.
The interface regulation method of the prelithiation electrode comprises the following steps:
1) and (3) soaking, standing and contacting the pre-lithiated graphite electrode plate with the interface regulating solution at room temperature under the argon atmosphere, and reacting for 2 hours.
2) And taking out the pre-lithiated graphite electrode slice which is in contact with the interface regulating liquid, and drying in vacuum at the temperature of 80 ℃ to obtain the interface regulated pre-lithiated electrode.
The pre-lithiated electrode prepared in this example after interface adjustment is subjected to XRD testing, and a test picture is shown in fig. 3.
The pre-lithiated electrode prepared in this example after interface adjustment is assembled into a button half cell for electrochemical test, which is the same as the method in example 1, and the test charge-discharge curve is shown in fig. 4, and the coulombic efficiency curve is shown in fig. 5.
Example 3
The embodiment provides a preparation process of an interface regulation liquid and an interface regulation method of a prelithiation electrode, which comprises the following steps:
the procedure for making the prelithiated pole pieces was the same as in example 1.
The preparation process of the interface regulating liquid comprises the following steps:
1) lithium perchlorate is dissolved in dimethyl carbonate and ethylene carbonate (volume ratio is 1: 1) to obtain a solution having a lithium salt concentration of 0.5 g/mL.
2) And (3) under the argon atmosphere, stirring and mixing the solution uniformly by magnetic force at room temperature to obtain the interface regulating and controlling solution for the pre-lithiation electrode. Wherein the magnetic stirring speed is 50rpm, and the magnetic stirring time is 12 hours.
The interface regulation method of the prelithiation electrode comprises the following steps:
1) and (3) soaking, standing and contacting the pre-lithiated graphite electrode slice with the interface regulating solution at room temperature in an argon atmosphere, and reacting for 1 hour.
2) And taking out the pre-lithiated graphite electrode slice which is in contact with the interface regulating and controlling solution, and drying in vacuum at the temperature of 60 ℃ to obtain the pre-lithiated electrode after interface regulation and control.
The pre-lithiated electrode prepared in this example after interface adjustment is subjected to XRD testing, and a test picture is shown in fig. 3.
The pre-lithiated electrode prepared in this example and subjected to interface regulation is assembled into a button half cell for electrochemical testing, and the charging and discharging curve of the test is shown in fig. 4, and the coulombic efficiency curve is shown in fig. 5 in the same way as in example 1.
Example 4
The embodiment provides a preparation process of an interface regulation liquid and an interface regulation method of a prelithiation electrode, which comprises the following steps:
the procedure for making the prelithiated pole pieces was the same as in example 1.
The preparation process of the interface regulating liquid comprises the following steps:
1) lithium hexafluorophosphate was dissolved in a propylene carbonate solvent to obtain a solution having a lithium salt concentration of 0.1 g/mL.
2) And (3) under the argon atmosphere, stirring and mixing the solution uniformly by magnetic force at room temperature to obtain the interface regulating and controlling solution for the pre-lithiation electrode. Wherein the magnetic stirring speed is 1000rpm, and the magnetic stirring time is 4 hours.
The interface regulation method of the prelithiation electrode comprises the following steps:
1) and (3) soaking, standing and contacting the pre-lithiated graphite electrode plate with the interface regulating solution at room temperature under the argon atmosphere, and reacting for 48 hours.
2) And taking out the pre-lithiated graphite electrode slice which is in contact with the interface regulating liquid, and drying in vacuum at 100 ℃ to obtain the interface regulated pre-lithiated electrode.
XRD test was performed on the pre-lithiated electrode after interface adjustment and the test picture is shown in fig. 3.
The pre-lithiated electrode prepared in this example after interface adjustment is assembled into a button half cell for electrochemical test, which is the same as the method in example 1, and the test charge-discharge curve is shown in fig. 4, and the coulombic efficiency curve is shown in fig. 5.
Example 5
The embodiment provides a preparation process of an interface regulation liquid and an interface regulation method of a prelithiation electrode, which comprises the following steps:
the procedure for making the prelithiated pole pieces was the same as in example 1.
The preparation process of the interface regulating liquid comprises the following steps:
1) lithium hexafluorophosphate and acetylene black were dissolved in dimethyl carbonate and ethylene carbonate (volume ratio 1: 1) to give a solution of a lithium salt at a concentration of 10g/mL, wherein the concentration of acetylene black was 0.1 g/mL.
2) And (3) under the argon atmosphere, stirring and mixing the solution uniformly by magnetic force at room temperature to obtain the interface regulating and controlling solution for the pre-lithiation electrode. Wherein the magnetic stirring speed is 1000rpm, and the magnetic stirring time is 2 hours.
The interface regulation method of the prelithiation electrode comprises the following steps:
1) and (3) soaking, standing and contacting the pre-lithiated graphite electrode plate with the interface regulating solution at room temperature under the argon atmosphere, and reacting for 10 minutes.
2) And taking out the pre-lithiated graphite electrode slice which is in contact with the interface regulating and controlling solution, and drying in vacuum at the temperature of 60 ℃ to obtain the pre-lithiated electrode after interface regulation and control.
The pre-lithiated electrode prepared in this example after interface adjustment is subjected to XRD testing, and a test picture is shown in fig. 3.
The pre-lithiated electrode prepared in this example and subjected to interface regulation is assembled into a button half cell for electrochemical testing, and the charging and discharging curve of the test is shown in fig. 6, and the coulombic efficiency curve is shown in fig. 7 in the same way as in example 1.
Example 6
The embodiment provides a preparation process of an interface regulation liquid and an interface regulation method of a prelithiation electrode, which comprises the following steps:
the procedure for making the prelithiated pole pieces was the same as in example 1.
The preparation process of the interface regulating liquid comprises the following steps:
1) lithium bis (fluorosulfonyl) imide and carboxymethyl cellulose were dissolved in dimethyl carbonate and ethylene carbonate (volume ratio 1: 1) to obtain a solution of a lithium salt at a concentration of 2g/mL, wherein the concentration of carboxymethyl cellulose is 0.05g/mL
2) And (3) under the argon atmosphere, stirring and mixing the solution uniformly by magnetic force at room temperature to obtain the interface regulating and controlling solution for the pre-lithiation electrode. The magnetic stirring speed is between 50rpm and 2000rpm, and the magnetic stirring time is between 1 second and 48 hours
The interface regulation method of the prelithiation electrode comprises the following steps:
1) and (3) soaking, standing and contacting the pre-lithiated graphite electrode plate with the interface regulating solution at room temperature under the argon atmosphere, and reacting for 10 minutes.
2) And taking out the pre-lithiated graphite electrode slice which is in contact with the interface regulating and controlling solution, and drying in vacuum at the temperature of 60 ℃ to obtain the pre-lithiated electrode after interface regulation and control.
XRD test was performed on the pre-lithiated electrode after interface adjustment and the test picture is shown in fig. 3.
The pre-lithiated electrode prepared in this example after interface adjustment is assembled into a button half cell for electrochemical test, which is the same as the method in example 1, and the test charge-discharge curve is shown in fig. 6, and the coulombic efficiency curve is shown in fig. 7.
Example 7
The embodiment provides a preparation process of an interface regulation liquid and an interface regulation method of a prelithiation electrode, which comprises the following steps:
the procedure for making the prelithiated pole pieces was the same as in example 1.
The preparation process of the interface regulating liquid comprises the following steps:
1) lithium hexafluorophosphate was dissolved in a fluoroethylene carbonate solvent to obtain a solution having a lithium salt concentration of 1 mol/L.
2) And (3) under the argon atmosphere, uniformly mixing the solution at room temperature by magnetic stirring to obtain the interface regulating solution for the pre-lithiation electrode. Wherein the magnetic stirring speed is 1000rpm, and the magnetic stirring time is 1 hour.
The interface regulation method of the prelithiation electrode comprises the following steps:
1) and (3) soaking, standing and contacting the pre-lithiated graphite electrode slice with the interface regulating solution at room temperature in an argon atmosphere, and reacting for 50 minutes.
2) And taking out the pre-lithiated graphite electrode slice which is in contact with the interface regulating and controlling solution, and drying in vacuum at the temperature of 60 ℃ to obtain the pre-lithiated electrode after interface regulation and control.
XRD test was performed on the pre-lithiated electrode after interface adjustment and the test picture is shown in fig. 3.
The pre-lithiated electrode prepared in this example after interface adjustment is assembled into a button half cell for electrochemical test, which is the same as the method in example 1, and the test charge-discharge curve is shown in fig. 6, and the coulombic efficiency curve is shown in fig. 7.
Example 8
The embodiment provides a preparation process of an interface regulation liquid and an interface regulation method of a prelithiation electrode, which comprises the following steps:
the procedure for making the prelithiated pole pieces was the same as in example 1.
The preparation process of the interface regulating liquid comprises the following steps:
1) lithium difluoride sulfonate imine salt and nano-alumina powder are dissolved in a fluoroethylene carbonate solvent to obtain a solution with the lithium salt concentration of 0.001g/mL, wherein the alumina concentration is 0.01 g/mL.
2) And (3) under the argon atmosphere, uniformly stirring and mixing the solution by magnetic force to obtain the interface regulating and controlling solution for the pre-lithiation electrode. Wherein the magnetic stirring speed is 2000rpm, and the magnetic stirring time is 2 hours
The interface regulation method of the prelithiation electrode comprises the following steps:
1) and (3) soaking, standing and contacting the pre-lithiated graphite electrode plate with the interface regulating solution at room temperature under the argon atmosphere, and reacting for 10 minutes.
2) And taking out the pre-lithiation graphite electrode slice which is in contact with the interface regulation liquid, and drying in vacuum at 60 ℃ to obtain the interface-regulated pre-lithiation electrode.
XRD test was performed on the pre-lithiated electrode after interface adjustment and the test picture is shown in fig. 3.
It should be noted that: examples 1 to 8 all used graphite electrodes, and the LiC possessed by ordinary graphite electrodes after lithium intercalation was investigated as the graphite electrode X Compound (LiC) X The compound (b) is a compound of Li and C having different compositions) is unstable to air and is easily miscible in airCO 2 And H 2 Reaction of O to Li 2 CO 3 At this time, active lithium stored in the graphite electrode is consumed, and LiC in a highly lithium intercalation state 12 LiC changed to low-insertion lithium state 18 Even LiC 24 Thereby weakening the lithium supplementing effect of the graphite electrode.
As can be seen from FIG. 3, the LiC is present at the peak positions of the pre-lithiated graphite electrodes after interface adjustment in examples 1 to 8 12 The components show that the chemical compositions of Li and C in the pre-lithiated graphite electrode subjected to interface regulation in examples 1 to 8 are not changed obviously, and the pre-lithiated graphite electrode treated by the interface regulation liquid has stability to air.
The pre-lithiated electrode prepared in this example after interface adjustment is assembled into a button half cell for electrochemical test, which is the same as the method in example 1, and the test charge-discharge curve is shown in fig. 6, and the coulombic efficiency curve is shown in fig. 7.
Example 9
The embodiment provides a preparation process of an interface regulation liquid and an interface regulation method of a prelithiation electrode, which comprises the following steps:
preparing a pre-lithiated pole piece: pre-lithiating the silicon-carbon composite electrode plate, selecting a 1mol/L tetramethyl diphenyllithium-tetrahydrofuran solution as a pre-lithiation reagent, and carrying out contact reaction on the silicon-carbon composite electrode plate and the pre-lithiation solution for 30 minutes to obtain the pre-lithiated silicon-carbon composite electrode plate.
The preparation process of the interface regulating liquid comprises the following steps:
1) lithium hexafluorophosphate was dissolved in dimethyl carbonate and ethylene carbonate (volume ratio 1: 1) to obtain a solution having a lithium salt concentration of 10 g/mL.
2) And (3) under the argon atmosphere, stirring and mixing the solution uniformly by magnetic force at room temperature to obtain the interface regulating and controlling solution for the pre-lithiation electrode. Wherein the magnetic stirring speed is 1000rpm, and the stirring time is 2 hours.
The interface regulation method of the prelithiation electrode comprises the following steps:
1) and (3) soaking, standing and contacting the pre-lithiated silicon-carbon composite electrode plate with the prepared interface regulating and controlling solution at room temperature in an argon atmosphere for 30 minutes.
2) And taking out the pre-lithiated silicon-carbon composite electrode plate which is in contact with the interface regulating and controlling solution, and drying in vacuum at 100 ℃ to obtain the interface regulated and controlled pre-lithiated electrode.
Example 10
The embodiment provides a preparation process of an interface regulation liquid and an interface regulation method of a prelithiation electrode, which comprises the following steps:
preparing a pre-lithiated pole piece: pre-lithiating the nickel-cobalt-manganese ternary electrode plate, selecting 1mol/L biphenyllithium-ethylene glycol dimethyl ether solution as a pre-lithiation reagent, and carrying out contact reaction on the nickel-cobalt-manganese ternary electrode plate and the pre-lithiation solution for 20 minutes to obtain the pre-lithiated nickel-cobalt-manganese ternary electrode plate.
The preparation process of the interface regulating liquid comprises the following steps:
1) lithium hexafluorophosphate was dissolved in dimethyl carbonate and ethylene carbonate (volume ratio 1: 1) to obtain a solution of a lithium salt having a concentration of 5 g/mL.
2) And (3) under the argon atmosphere, stirring and mixing the solution uniformly by magnetic force at room temperature to obtain the interface regulating and controlling solution for the pre-lithiation electrode. Wherein, the speed of magnetic stirring is 800rpm, and the stirring time is 1 hour.
The interface regulation method of the prelithiation electrode comprises the following steps:
1) and (3) soaking, standing and contacting the pre-lithiated nickel-cobalt-manganese ternary electrode plate with the prepared interface regulating and controlling solution at room temperature in an argon atmosphere for 20 minutes.
2) And taking out the pre-lithiated nickel-cobalt-manganese ternary electrode plate which is in contact with the interface regulating and controlling solution, and drying in vacuum at the temperature of 60 ℃ to obtain the pre-lithiated electrode after interface regulation and control.
To better illustrate the effects of the examples of the present invention, comparative examples were compared with the above examples.
Comparative example 1
And (4) carrying out electrochemical performance test on the original graphite pole piece without processing.
The graphite electrode sheet of this comparative example was subjected to XRD testing, and the test picture is shown in fig. 8.
The graphite pole piece of the comparative example is assembled into a button type half cell for electrochemical test, the method is the same as the method of the example 1, the test charge-discharge curve chart is shown in figure 9, and the coulombic efficiency curve chart is shown in figure 10.
Comparative example 2
The pre-lithiation solution biphenyl lithium-dimethyl tetrahydrofuran solution (1mol/L) is used for carrying out pre-lithiation treatment on the natural graphite pole piece, but interface regulation and control are carried out on the pre-lithiation graphite electrode without using an interface regulation and control solution, a battery is directly assembled for testing, and the assembling method and the testing method are the same as those in example 1.
The pre-lithiated graphite electrode of this comparative example, which was not subjected to interface modulation, was subjected to XRD testing, and the test picture is shown in fig. 8.
The pre-lithiated graphite electrode which is not subjected to interface regulation and control and is used for assembling a button type half cell for electrochemical test, the method is the same as that of the embodiment 1, the test charge-discharge curve chart is shown in figure 9, and the coulombic efficiency curve chart is shown in figure 10.
The results of testing the cycle capacity and the initial efficiency of the interface-regulated pre-lithiated electrode-assembled battery prepared in the embodiment of the present invention are shown in table 1.
TABLE 1
As can be seen from the comparison of the data in table 1, the batteries of examples 1 to 8 and the battery of comparative example 2 all had better cycle capacity, cycle stability and initial efficiency than the battery of comparative example 1 because the pristine graphite employed in comparative example 1 was not subjected to the pre-lithiation treatment and was not subjected to the lithium supplement treatment, and thus the initial efficiency of the assembled battery was inferior to those of examples 1 to 8 and comparative example 2.
The cycle capacity and the cycle stability of the battery assembled by the pre-lithiated electrode after interface regulation and control in examples 1 to 8 are superior to those of the battery assembled by the pre-lithiated and untreated graphite electrode in comparative example 2, because the pre-lithiation solution remained on the surface of the pre-lithiated graphite electrode in comparative example 2 affects the cycle capacity of the battery and reduces the cycle capacity of the battery, while the interface regulation and control solution in examples 1 to 8 can react with the pre-lithiation solution remained on the surface of the pre-lithiated electrode to form an inorganic lithium salt-containing solid electrolyte layer on the surface of the pre-lithiated electrode, so that the lithium supplementing effect of the pre-lithiation on the electrode can be effectively maintained, the electrode interface component can be regulated and controlled, the content of the generated inorganic lithium salt is higher than that generated by the electrochemical reaction between the electrode and the electrolyte, and the battery assembled by the interface regulation and control method has good mechanical property and electrochemical stability, can effectively inhibit the growth of lithium dendrite and reduce the occurrence of side reaction of the battery, and is more beneficial to improving the cycle performance of the battery.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. An interface regulating liquid for a prelithiation electrode is characterized by comprising a solvent and a metal salt;
the solvent comprises: one or more of an ether solvent, an ester solvent, a ketone solvent, a hydrocarbon solvent, a nitrile solvent or deionized water;
the metal salt includes: one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium bis (oxalato) borate, lithium bis (fluorosulfonate) imide, lithium bis (trifluoromethylsulfonyl) imide, lithium perchlorate, lithium fluoride and lithium chloride; the concentration of the metal salt is 0.001g/mL-10 g/mL;
the pre-lithiation electrode is obtained by supplementing lithium to the electrode by using a chemical pre-lithiation solution;
the interface regulating and controlling liquid is used for modifying the pre-lithiation electrode, the metal salt of the interface regulating and controlling liquid reacts with the chemical pre-lithiation solution remained on the surface of the pre-lithiation electrode, and a solid electrolyte layer containing inorganic lithium salt is generated on the surface of the pre-lithiation electrode; wherein, the content of the inorganic lithium salt is between 5 and 90 percent.
2. The interface control fluid for prelithiation of an electrode according to claim 1, wherein the interface control fluid comprises a first liquid and a second liquid,
the content of the inorganic lithium salt is between 40 and 90 percent;
the solvent specifically comprises: one or more of methyl propyl ether, methyl butyl ether, methyl amyl ether, ethyl propyl ether, ethyl butyl ether, ethyl amyl ether, propyl butyl ether, propyl amyl ether, tetrahydrofuran, methyl tetrahydrofuran, dimethyl tetrahydrofuran, ethyl tetrahydrofuran, diethyl tetrahydrofuran, phenyl tetrahydrofuran, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate, diphenyl carbonate, dibutyl carbonate, butylene carbonate, ethyl methyl carbonate, fluoroethylene carbonate, trimethylene carbonate, ethylene chlorocarbonate, vinylene carbonate, or deionized water;
the chemical pre-lithiation solution comprises one or more of a biphenyl lithium-dimethyl tetrahydrofuran solution, a biphenyl lithium-ethylene glycol dimethyl ether solution, a tetramethyl biphenyl lithium-dimethyl tetrahydrofuran solution, a tetramethyl biphenyl lithium-ethylene glycol dimethyl ether solution, a naphthalene lithium-dimethyl tetrahydrofuran solution, a naphthalene lithium-ethylene glycol dimethyl ether solution or a liquid ammonia-lithium solution.
3. The interfacial regulation fluid for prelithiation of an electrode according to claim 1, further comprising a conductive additive; the conductive additive specifically includes: one or more of carbon black, acetylene black, ketjen black, carbon nanotubes, graphene oxide, carbon fibers and carbon quantum dots;
the interface regulating liquid also comprises a binder; the binder specifically includes: one or more of polyvinylidene fluoride, carboxymethyl cellulose, polytetrafluoroethylene, polyacrylic acid, styrene butadiene rubber, polyvinyl alcohol, polybutyl acrylate and polyacrylonitrile;
the interface regulating liquid also comprises functional filler; the functional filler specifically comprises: one or more of boron nitride, aluminum nitride, silicon carbide, magnesium oxide, beryllium oxide, aluminum oxide, zinc oxide, silicon oxide, gold powder, silver powder, copper powder, nickel powder and aluminum powder.
4. The interfacial regulation fluid for prelithiation electrodes according to claim 1, wherein the active materials of the prelithiation electrode comprise: lithium iron phosphate, lithium cobaltate, lithium nickelate, lithium manganate, nickel cobalt manganese ternary material, nickel cobalt aluminum ternary material, lithium-rich ternary material, lithium nickel manganese oxide, copper fluoride, cobalt fluoride, cobaltous fluoride, ferric fluoride, ferrous fluoride, manganese fluoride, nickel fluoride, zinc fluoride, niobium fluoride, molybdenum chloride, ferric chloride, ferroferric oxide, vanadium pentoxide, nickel sulfide, cobalt sulfide, silicon sulfide, tetraphosphorus heptasulfide, phosphorus pentasulfide, copper oxide, strontium oxide, cobalt oxide, ferric oxide, manganese dioxide, molybdenum trioxide, lithium titanate, lithium vanadate, silicon carbon composite material, silicon monoxide carbon composite material, silicon oxide, silicon dioxide, natural graphite, artificial graphite, graphene, carbon nanotubes, and carbon nanofibers.
5. A method for preparing the interface control solution for the prelithiation electrode according to any one of claims 1 to 4, wherein the method comprises:
mixing a solvent and a metal salt according to a proportion to obtain a metal salt solution;
under the inert atmosphere, the ambient temperature is between-10 ℃ and 100 ℃, and the metal salt solution is stirred and mixed uniformly by magnetic force to obtain interface regulating and controlling liquid for the pre-lithiation electrode;
the solvent comprises: one or more of an ether solvent, an ester solvent, a ketone solvent, a hydrocarbon solvent, a nitrile solvent or deionized water;
the metal salt includes: one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium bis (oxalato) borate, lithium bis (fluorosulfonate) imide, lithium bis (trifluoromethylsulfonyl) imide, lithium perchlorate, lithium fluoride and lithium chloride; the concentration of the metal salt is 0.001g/mL-10 g/mL;
the pre-lithiation electrode is obtained by supplementing lithium to the electrode by using a chemical pre-lithiation solution;
the interface regulating and controlling liquid is used for modifying the pre-lithiation electrode, the metal salt of the interface regulating and controlling liquid reacts with the chemical pre-lithiation solution remained on the surface of the pre-lithiation electrode, and a solid electrolyte layer containing inorganic lithium salt is generated on the surface of the pre-lithiation electrode; wherein, the content of the inorganic lithium salt is between 5 and 90 percent.
6. The method for preparing the interface control solution for the prelithiation electrode according to claim 5, wherein the solvent specifically comprises: one or more of methyl propyl ether, methyl butyl ether, methyl pentyl ether, ethyl propyl ether, ethyl butyl ether, ethyl pentyl ether, propyl butyl ether, propyl pentyl ether, tetrahydrofuran, methyl tetrahydrofuran, dimethyl tetrahydrofuran, ethyl tetrahydrofuran, diethyl tetrahydrofuran, phenyl tetrahydrofuran, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate, diphenyl carbonate, dibutyl carbonate, butylene carbonate, ethyl methyl carbonate, fluoroethylene carbonate, trimethylene carbonate, ethylene chlorocarbonate, vinylene carbonate, or deionized water;
the chemical pre-lithiation solution comprises one or more of a biphenyl lithium-dimethyl tetrahydrofuran solution, a biphenyl lithium-ethylene glycol dimethyl ether solution, a tetramethyl biphenyl lithium-dimethyl tetrahydrofuran solution, a tetramethyl biphenyl lithium-ethylene glycol dimethyl ether solution, a naphthalene lithium-dimethyl tetrahydrofuran solution, a naphthalene lithium-ethylene glycol dimethyl ether solution or a liquid ammonia-lithium solution;
the interface regulating liquid also comprises a conductive additive; the conductive additive specifically includes: one or more of carbon black, acetylene black, ketjen black, carbon nanotubes, graphene oxide, carbon fibers and carbon quantum dots;
the interface regulating liquid also comprises a binder; the binder specifically includes: one or more of polyvinylidene fluoride, carboxymethyl cellulose, polytetrafluoroethylene, polyacrylic acid, styrene butadiene rubber, polyvinyl alcohol, polybutyl acrylate and polyacrylonitrile;
the interface regulating liquid also comprises functional filler; the functional filler specifically comprises: one or more of boron nitride, aluminum nitride, silicon carbide, magnesium oxide, beryllium oxide, aluminum oxide, zinc oxide, silicon oxide, gold powder, silver powder, copper powder, nickel powder and aluminum powder.
7. The method for preparing the interface control solution for the prelithiation electrode according to claim 5, wherein the magnetic stirring speed is between 50rpm and 2000rpm, and the magnetic stirring time is between 1 second and 48 hours.
8. An interface regulation method of a prelithiation electrode, the interface regulation method comprising: contacting a prelithiated electrode with an interfacial modified liquid phase as claimed in any one of claims 1 to 4, in an inert atmosphere;
naturally airing or drying the pre-lithiation electrode contacted with the interface regulation and control solution to obtain a pre-lithiation electrode after interface regulation and control;
the interface-regulated pre-lithiated electrode has stability to air.
9. The interface regulation method of the prelithiation electrode according to claim 8, wherein the contacting is by immersion standing contact; the soaking, standing and contacting is to carry out contact reaction at the temperature of-40-200 ℃, and the contact reaction time is between 1 second and 72 hours;
the drying temperature is between-10 ℃ and 300 ℃;
the active material of the prelithiated electrode includes: lithium iron phosphate, lithium cobaltate, lithium nickelate, lithium manganate, nickel cobalt manganese ternary material, nickel cobalt aluminum ternary material, lithium-rich ternary material, lithium nickel manganese oxide, copper fluoride, cobalt fluoride, cobaltous fluoride, ferric fluoride, ferrous fluoride, manganese fluoride, nickel fluoride, zinc fluoride, niobium fluoride, molybdenum chloride, ferric chloride, ferroferric oxide, vanadium pentoxide, nickel sulfide, cobalt sulfide, silicon sulfide, tetraphosphorus heptasulfide, phosphorus pentasulfide, copper oxide, strontium oxide, cobalt oxide, ferric oxide, manganese dioxide, molybdenum trioxide, lithium titanate, lithium vanadate, silicon carbon composite material, silicon monoxide carbon composite material, silicon oxide, silicon dioxide, natural graphite, artificial graphite, graphene, carbon nanotubes, and carbon nanofibers.
10. A lithium battery comprising the interface-conditioned prelithiated electrode of claim 8.
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| CN117117332A (en) * | 2023-02-21 | 2023-11-24 | 荣耀终端有限公司 | Preparation method of lithium-supplementing battery, lithium-supplementing battery and electronic equipment |
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