WO2014044039A1 - 复合硅酸盐正极材料、锂电池及其制备方法、通信设备 - Google Patents

复合硅酸盐正极材料、锂电池及其制备方法、通信设备 Download PDF

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WO2014044039A1
WO2014044039A1 PCT/CN2013/073380 CN2013073380W WO2014044039A1 WO 2014044039 A1 WO2014044039 A1 WO 2014044039A1 CN 2013073380 W CN2013073380 W CN 2013073380W WO 2014044039 A1 WO2014044039 A1 WO 2014044039A1
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positive electrode
lithium battery
electrode material
silicate
battery
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PCT/CN2013/073380
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English (en)
French (fr)
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廖华栋
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华为技术有限公司
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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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • 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
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M10/058—Construction or manufacture
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • 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
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M4/1397—Processes of manufacture of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • 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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • H01M4/623—Binders being polymers fluorinated polymers
    • 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
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the invention belongs to the technical field of batteries, and particularly relates to a composite silicate positive electrode material and a preparation method thereof, a lithium battery and a preparation method thereof, a lithium battery positive electrode, a preparation method thereof and a communication device. Background technique
  • the lithium ion battery mainly comprises three parts of a positive electrode, an electrolyte solution and a negative electrode.
  • the electrode material of the lithium ion battery is essential for improving the electrochemical performance and lowering the cost of the battery. Since the negative electrode material uses a modified graphite material, it has a high specific capacity. Therefore, the current research on lithium ion battery electrode materials is mainly focused on the development of excellent positive electrode materials.
  • the silicate positive electrode material is a new type of polyanionic positive electrode material belonging to the orthorhombic system. All cations and oxygen atoms are tetrahedron-related. Compared with the phosphoric acid source cathode material, the silicate cathode material can theoretically allow reversible deintercalation of two lithiums, thus having a higher theoretical capacity, which makes the silicate material a very attractive new lithium ion cathode material. .
  • the preparation of conventional silicate positive electrode materials is mainly synthesized by a solid phase method and a liquid phase method.
  • the solid phase method is: Step 1) mixing the raw material lithium salt, ferrous salt, silica and additives in proportion, wherein the molar ratio of Li:Fe:Si is (1.9-2.1): (0.95-1.05): 1 , the additive is added in an amount of 1 to 30% of the total mass of the mixture; Step 2)
  • the uniformly mixed material is placed in a heat treatment apparatus, and heated at a flow rate of 100 to 5000 ml/min in an inert gas flow protection at a heating rate of 1 °C/min ⁇ 20 °C / min, when the temperature to be heat treated rises to 300 ° C ⁇ 450 ° C, keep, heat at this temperature for 1 ⁇ 30 hours, and then continue to heat up, at 700 ° C ⁇ 900 ° C Within the range, heat treatment for 10 hours to 48 hours, then slowly drop To room temperature, a lithium iron si
  • the liquid phase method is: adding lithium hydroxide and silicon oxide into water while dispersing the mixture of manganese salt and iron salt in water, stirring, moving into a hydrothermal kettle for hydrothermal reaction, washing with water, filtering, and drying to obtain target product silicon.
  • Lithium iron manganese oxide - lithium iron silicate Lithium iron manganese oxide - lithium iron silicate.
  • these methods may cause unreacted Fe compound impurities to remain in the product positive electrode material due to uneven mixing or uneven reaction during the preparation process.
  • these methods require multiple steps of high-energy ball milling mixing, drying, sintering, and scraping. The operation time is long.
  • the metal equipment, pipes, raw materials and environmental dust used will also introduce a part of Fe, Mn, Cr, Ni.
  • Metal impurities such as Zn and Cu.
  • metal impurities may adversely affect the battery capacity due to the charge and discharge of the battery, and may dissolve in the electrolyte to form metal cations as the battery is charged or discharged, or during long-term recycling of the battery, the electrolyte Oxidation or reaction with moisture produces hydrofluoric acid HF to react with the silicate positive electrode material to dissolve metal ions such as Fe and Mn.
  • the eluted metal cation gradually migrates to the negative electrode driven by the electric field, and finally deposits on the negative electrode and the separator of the battery, which increases the self-discharge of the battery, and severely pierces the diaphragm, causing a short circuit of the battery and causing a safety accident.
  • Technical Problem and Composite Silicate Cathode Material for Preventing Dissolution and Migration of Impurity Metal Ions and Preparation Method Therefor.
  • Another object of an embodiment of the present invention is to provide a lithium battery positive electrode comprising the composite silicate positive electrode material and a method of preparing the same.
  • a composite silicate positive electrode material comprising a nano silicate of the formula Li 2 MSi0 4 and a conductive agent and a functional polymer coated on the surface of the nano silicate and the conductive agent; wherein M is Co, At least one element of Mn, Fe, the functional polymer contains an excessive metal ion chelating functional group.
  • the above-mentioned excessive metal ion chelating functional group is at least one of -CO-, -COO-, -CN, -CON.
  • the above functional polymer is obtained by copolymerizing a decyl methacrylate monomer having a molar ratio of 1:1 to 10 with a vinyl monomer having a chelate functional group containing the above-mentioned excessive metal ion.
  • the above functional polymer accounts for 1 to 10% of the total mass of the composite silicate positive electrode material.
  • the conductive agent accounts for 1% to 3% of the total mass of the composite silicate positive electrode material.
  • the composite silicate positive electrode material has a particle diameter of 5 to 20 ⁇ .
  • the conductive agent is at least one of carbon nanotubes, nanocarbon fibers, carbon black, and acetylene black.
  • the silicate-containing slurry is spray-dried to obtain the composite silicate positive electrode material.
  • the mixture is reacted at 40 to 80 ° C with stirring, and then a crosslinking agent is added to continue the stirring reaction to obtain a polymerization product;
  • the polymerized product was suction filtered and dried to obtain the functional polymer.
  • the initiator is added in an amount of from 1% to 10% by mass based on the total mass of the methyl methacrylate monomer and the ethoxymer monomer.
  • the crosslinking agent is added in an amount of from 0.02% to 0.1% by weight based on the total mass of the methyl methacrylate monomer and the ethoxymer monomer.
  • the above initiator is an oily initiator or a water-soluble hair agent.
  • the crosslinking agent is at least one of hydrazine, hydrazine-methylene bis acrylamide, diisocyanate, and dicumyl peroxide.
  • the functional polymer solution has a mass percentage concentration of 1 to 10%.
  • the above nanosilicate has a particle diameter of 50 to 200 nm.
  • a lithium battery positive electrode comprising a current collector and an active layer containing a positive electrode material bonded to the current collector, wherein: the positive electrode material is a composite silicate positive electrode material as described above.
  • the above composite silicate positive electrode material is mixed with an electrode conductive agent and a binder to prepare a positive electrode slurry;
  • the current collector coated with the positive electrode slurry was subjected to drying treatment, rolling, and cutting to obtain a positive electrode of a lithium battery.
  • the weight ratio of the above composite silicate positive electrode material, electrode conductive agent and adhesive is 100: (1 ⁇ 5): (1 ⁇ 5).
  • the electrode conductive agent is at least one of carbon black, carbon nanotubes, carbon nanofibers, and acetylene black; and the binder is polyvinylidene fluoride.
  • the lithium battery is an electrochemical lithium battery electrochemically reacted.
  • the electrochemical lithium battery of the above electrochemical reaction is a lithium ion battery, a lithium polymer battery, a lithium battery or a lithium air battery.
  • the battery cell is placed in a battery case, and then an electrolyte is injected and sealed to obtain a lithium battery.
  • the embodiment of the invention further discloses a communication device, comprising: a working module and a power supply module, wherein the power supply module comprises the lithium battery; the power supply module provides power for the working module, and the working module uses The power supply provided by the power supply module operates.
  • a communication device comprising: a working module and a power supply module, wherein the power supply module comprises the lithium battery; the power supply module provides power for the working module, and the working module uses The power supply provided by the power supply module operates.
  • the composite silicate positive electrode material of the above embodiment coats the nano silicate with a functional polymer containing a chelating functional group of excessive metal ions, and the chelation of the functional group can effectively capture the excessive dissolution from the nano silicate.
  • An impurity metal ion such as a metal suppresses and prevents elution and migration of the impurity metal ion.
  • the positive electrode of the lithium battery of the above embodiment has the above composite silicate positive electrode material, and since the composite silicate positive electrode material can effectively inhibit and prevent the elution and migration of the impurity metal ion as described above, the positive electrode is in the working process. Among them, the impurity metal ions in the silicate can be effectively suppressed and prevented from being eluted and migrated from the positive electrode. Since the lithium battery of the above embodiment contains the above positive electrode of the lithium battery, the lithium battery can effectively suppress and prevent the elution of the impurity metal ions contained in the silicate from the positive electrode during charge and discharge cycle, storage and/or long-term recycling.
  • the lithium battery has improved cycle performance and high temperature storage performance, which prolongs the service life of the lithium battery.
  • the power supply module of the communication device can provide stable and continuous power supply to the working module, improve the safety performance of the high communication device, and reduce the battery in the power supply module.
  • the frequency of replacement reduces the cost of running the communication device.
  • the preparation method of the composite silicate positive electrode material, the lithium battery positive electrode and the lithium battery in the above embodiments is simple, the conditions are easy to control, the efficiency is high, and the method is suitable for industrial production.
  • FIG. 1 is a scanning electron micrograph of a composite silicate positive electrode material according to an embodiment of the present invention.
  • FIG. 2 is a flow chart of a method for preparing a composite silicate positive electrode material according to an embodiment of the present invention
  • FIG. 3 is a flow chart of a method for preparing a positive electrode of a lithium battery according to an embodiment of the present invention
  • FIG. 4 is a flow chart of a method for preparing a lithium battery according to an embodiment of the present invention.
  • the present invention provides a composite silicate positive electrode material which is effective for suppressing and preventing the elution and migration of impurity metal ions.
  • the composite silicate positive electrode material comprises a nano silicate of the formula Li 2 MSi0 4 and a conductive agent, and a functional polymer coated on the surface of the nano silicate and the conductive agent; wherein, M The at least one element of Co, Mn, Fe, the functional polymer contains an excessive metal ion chelating functional group.
  • the above nano silicate having the general formula Li 2 MSi0 4 can be prepared by a conventional method, for example, by a liquid phase method. Since the silicate can theoretically allow reversible deintercalation of two lithiums, the nanosilicate has a higher theoretical capacity as a positive electrode material.
  • the general formula Li 2 MSi0 4 of the nanosilicate is only used to define the basic elements constituting the silicate, and does not limit the relationship of the content of each element.
  • the nanosilicate of the formula Li 2 MSi0 4 may be a silicate positive electrode material such as lithium iron silicate (Li 2 FeSi0 4 ), lithium manganese silicate (Li 2 FeSi0 4 ) or lithium manganese silicate.
  • the above conductive agent is present to enhance the electrical conductivity of the composite silicate positive electrode material.
  • the conductive agent is preferably at least one of carbon nanotubes, nanocarbon fibers, carbon black, and acetylene black.
  • the conductive agent may also be a conductive agent commonly used in the art.
  • the conductive agent preferably accounts for 1% to 3% of the total mass of the composite silicate positive electrode material.
  • the above functional polymer can effectively capture the impurity metal ions contained in the above-mentioned nanosilicate coated by the excessive metal ion chelating functional group, and inhibit and prevent the migration and elution of the impurity metal ions into the composite silicate positive electrode material. Outside.
  • the functional polymer contains an excessive metal ion chelating functional group of at least one of -CO-, -COO-, -CN, -CON.
  • the excessive metal ion chelating functional group is more effective in chelation of excessive metal impurity ions, inhibiting and preventing migration and dissolution of impurity ions.
  • the excessive metal ion chelating functional group may also be another functional group in the art capable of chelation with excessive metal ions.
  • the functional polymer is preferably obtained by copolymerizing a decyl methacrylate monomer having a molar ratio of 1 : 1 to 10 and a vinyl monomer containing the excessive metal ion chelating functional group.
  • the functional polymer is obtained as follows:
  • Step (1) mixing an initiator, an oxime methacrylate monomer having a molar ratio of 1:1 to 10, a vinyl monomer containing the excessive metal ion chelating functional group, and a solvent under an oxygen-free condition Shape Into a mixture;
  • Step (2) reacting the mixture in the step (1) at 40 to 80 ° C with stirring, and then adding a crosslinking agent to continue stirring the reaction to obtain a polymerization product;
  • Step (3) The polymerization product in the step (2) is subjected to suction filtration and dried to obtain the functional polymer.
  • the solvent in the above step (1) may be selected according to the solubility property of the reactive monomer, and the corresponding organic solvent or deionized water may be added in a total amount of the decyl methacrylate monomer and the ethylenic monomer. 5 to 10 times the mass.
  • the initiator may be selected from an oily initiator (e.g., benzoyl peroxide BPO, azobisisobutyronitrile AIBN, etc.) or a water-soluble initiator (e.g., hydrogen peroxide, ammonium persulfate, etc.) depending on the solvent selected.
  • an oily initiator e.g., benzoyl peroxide BPO, azobisisobutyronitrile AIBN, etc.
  • a water-soluble initiator e.g., hydrogen peroxide, ammonium persulfate, etc.
  • the initiator is added in an amount of 1% to 10% of the total mass of both the decyl methacrylate monomer and the vinyl monomer.
  • the excessive metal ion chelating functional group in the vinyl monomer is at least one of -CO-, -COO-, -CN, -CON.
  • the excessive metal ion chelating functional group contained in the vinyl monomer may contain only one or one of the functional groups, or may contain two or more of the functional groups at the same time, that is, in the embodiment of the present invention.
  • the type and amount of the excessive metal ion chelating functional group contained in the ethylene monomer are not particularly limited.
  • the anaerobic condition in the step (1) may be an anaerobic condition of vacuum or an anaerobic condition filled with nitrogen.
  • the crosslinking agent in the step (2) is added in an amount of 0.02% of the total mass of the decyl acrylate monomer and the ethoxymer monomer or the total mass of the decyl acrylate monomer and the ethoxymer monomer. 0.1%.
  • the crosslinking agent is at least one of hydrazine, fluorenyl-indenyl bis acrylamide, diisocyanate, and dicumyl peroxide.
  • the reaction time of the mixture in the step (1) is 0.5 to 24 hours, and the time of adding the crosslinking agent is 2 to 12 minutes.
  • the suction filtration and the drying treatment in the step (3) can be carried out in a manner conventional in the art.
  • the composite silicate positive electrode material of the above embodiment have a certain content of excessive metal ion chelating functional groups to achieve better sequestration of impurity metal ions in the nanosilicate without affecting the transfer of lithium ions, the above functional polymerization
  • the content of the substance is preferably from 1 to 10%, more preferably from 2 to 5%, based on the total mass of the composite silicate positive electrode material.
  • the particle size of the composite silicate positive electrode material is preferably controlled between 5 and 20 ⁇ , and the composite silicate positive electrode material of the preferred particle size range has good electrical conductivity and high capacity.
  • the particle size can be other sizes if the optimum conductivity and capacity are not considered.
  • the functional polymer in the composite silicate positive electrode material of the above embodiment may be coated with the nanosilicate and the conductive agent in a manner other than the following:
  • the functional polymer is coated on the outer surface of the nanosilicate, wherein the conductive agent is doped in the nanosilicate.
  • the functional polymer coating may be a full coating or a partial coating or as a specific embodiment, the functional polymer is coated on the outer surface of the nanosilicate and the conductive agent, respectively. Wherein, the functional polymer coating may be fully coated or partially coated.
  • the above functional polymer is a mixture of the composite silicate positive electrode materials in the above two specific examples.
  • the composite silicate positive electrode material of the above embodiment coats the nano silicate with a functional polymer containing an excessive metal ion chelating functional group, and the chelation of the functional group can effectively capture the nano silicate from the nano silicate.
  • An impurity metal ion such as an excessive metal eluted in the salt suppresses and prevents elution and migration of the impurity metal ion.
  • the presence of the conductive agent can effectively improve the electrical conductivity of the composite silicate positive electrode material. Therefore, the composite silicate positive electrode material can effectively capture impurity metal ions such as excessive metals eluted from the nanosilicate, suppress and prevent elution and migration of the impurity metal ions, and has high capacity and good electrical conductivity.
  • the composite silicate positive electrode material of the above example was observed by a JX-5610LV type scanning electron microscope of Japan JEOL at a magnification of 5000 times to obtain an SEM image 1. It can be further confirmed from Fig. 1 that the surface of the silicate in the composite silicate positive electrode material of the embodiment of the invention is conductively polymerized. The layer is evenly coated.
  • the invention also provides a preparation method of the above composite silicate positive electrode material.
  • the process flow of the composite negative electrode preparation method is shown in Figure 2, which includes the following steps:
  • Step S01 Preparing a functional polymer solution: dissolving the functional polymer containing the excessive metal ion chelating functional group described above in a polar organic solvent to prepare a functional polymer solution;
  • Step S02. Preparing a silicate-containing slurry: mixing the above-mentioned conductive agent, nano silicate of the formula Li 2 MSi0 4 with the functional polymer solution prepared in step S01, and then sealing and grinding to obtain Silicate slurry;
  • Step S03 Spray drying the silicate-containing slurry: The silicate-containing slurry prepared in the step S02 is spray-dried to obtain the composite silicate positive electrode material.
  • the functional polymer containing the excessive metal ion chelating functional group in the above step S01 and the preparation method thereof are as described above, and in order to save space, no further details are provided herein.
  • the polar organic solvent is preferably one or a mixture of N-dimercaptophthalamide (DMF), acetone, and of course other commonly used polar organic solvents which are effective for dissolving functional polymers.
  • the mass percentage concentration of the functional polymer solution in this step S01 is preferably from 1 to 10%.
  • the ratio of the addition amount of the nano silicate, the conductive agent, and the conductive agent, the nano silicate, and the functional polymer in the above step S02 is Li 2 MSi0 4 as described above, in order to save space, I will not repeat them here.
  • the conductive agent, the nanosilicate and the functional polymer are mixed by: dispersing the conductive agent in a mixed with the functional polymer solution, and then adding the nanosilicate to mix; wherein The nanosilicate has a particle size of 50 to 200 nm. This allows the components to be uniformly dispersed.
  • the ultrasonic treatment step may be combined, so that the conductive agent, the nano silicate, especially the conductive agent are hooked in the slurry. Disperse and stabilize the slurry so that delamination does not occur.
  • the sealing and grinding in the step S02 is preferably performed by a ball mill for sealing ball milling.
  • the sealing and polishing time is preferably 8 ⁇ . 10 hours.
  • other grinding methods known in the art can also be used for sealing research. Grinding.
  • the spray drying in the above step S03 is to obtain a composite silicate positive electrode material in which the above functional polymer-coated nanosilicate is obtained.
  • the process conditions of the spray drying should be adjusted so that a composite silicate positive electrode material having a particle diameter of preferably 5 to 20 ⁇ is finally obtained.
  • the composite silicate positive electrode material preparation method comprises coating a functional polymer on a surface of a nano silicate and a conductive agent to form a composite silicate positive electrode material having a cladding structure.
  • the composite silicate positive electrode material has an excellent function of effectively capturing the impurity metal ions such as excessive metals eluted from the nanosilicate as described above, thereby suppressing and preventing the elution and migration of the impurity metal ions.
  • the method has the advantages of easy to control and high efficiency, and is suitable for industrial production.
  • the present invention further provides a lithium battery positive electrode comprising a current collector and an active layer containing a positive electrode material bonded to the current collector, wherein the positive electrode material is the composite silicate positive electrode material described above;
  • the fluid may be selected from a current collector commonly used in the art, such as aluminum foil.
  • the positive electrode of the lithium battery contains the composite silicate positive electrode material described above, and since the composite silicate positive electrode material can effectively inhibit and prevent the elution and migration of the impurity metal ion as described above, The lithium battery positive electrode can effectively inhibit and prevent the elution and migration of impurity metal ions in the silicate from the positive electrode during operation.
  • the present invention further provides a lithium battery positive electrode.
  • the preparation process of the positive electrode of the lithium battery is shown in Figure 3, which includes the following steps:
  • Step S04 Preparing a positive electrode slurry: mixing the composite silicate positive electrode material described above with an electrode conductive agent and a binder to prepare a positive electrode slurry;
  • Step S05 Applying the positive electrode slurry prepared in step S04 to the current collector;
  • Step S06 Drying, rolling and cutting treatment of the current collector:
  • the current collector coated with the positive electrode slurry treated in the step S05 is subjected to drying treatment, rolling, and cutting to obtain a positive electrode of the lithium battery.
  • the weight ratio of the composite silicate positive electrode material, the electrode conductive agent and the binder in the above step S04 is preferably 100: (1 to 5): (1 to 5), more preferably 100:3:3.
  • the above electrode conductive agent is carbon black, carbon nano At least one of a tube, a nano carbon fiber, and an acetylene black; the binder is polyvinylidene fluoride.
  • the electrode conductive agent and the binder may also be selected from other materials commonly used in the art.
  • the method of applying the positive electrode slurry in the above step S05 and the step S06 may be performed by a method commonly used in the art for drying, rolling and cutting the current collector.
  • the method for preparing a positive electrode of a lithium battery only needs to apply a positive electrode slurry containing the composite silicate positive electrode material described above on a current collector, and then drying, rolling, and cutting, the method is simple, the condition is simple Easy to control, high pass rate and high production efficiency.
  • the present invention also provides a lithium battery including the lithium battery positive electrode described above.
  • the lithium battery is an electrochemically reacted chemical lithium battery.
  • the electrochemical lithium battery of the electrochemical reaction is a lithium ion battery, a lithium polymer battery, a lithium sulfur battery or a lithium air battery.
  • the lithium battery contains the lithium battery positive electrode as described above, the lithium battery can effectively suppress and prevent impurity metal ions contained in the silicate during charge and discharge cycle, storage, and/or long-term recycling. Dissolving and migrating from the positive electrode, thereby avoiding the migration of the impurity metal ions to the negative electrode and finally depositing on the negative electrode and the separator to cause self-discharge of the battery, piercing the separator and causing a short circuit of the battery, thereby improving the lithium battery.
  • Safety performance and capacity, as well as improved lithium battery cycle performance and high temperature storage performance extend the life of the lithium battery.
  • the embodiment of the invention further provides a method for preparing a lithium battery.
  • the process flow of the lithium battery preparation method is shown in Figure 4, which includes the following steps:
  • Step S07 Preparing a positive electrode and a negative electrode of the lithium battery, wherein the positive electrode of the lithium battery is prepared by the method for preparing a positive electrode of the lithium battery described above;
  • Step S08 Preparing a battery cell: the positive electrode and the negative electrode of the battery prepared in step S07 are sequentially stacked in a negative stacking manner of a lithium battery positive electrode/separator/lithium battery, and wound up to form a battery cell;
  • Step S09 Encapsulating the battery: The battery cell is placed in the battery case, the electrolyte is injected, and sealed to obtain a lithium battery.
  • the preparation of the negative electrode in the above step S07, the preparation of the battery cell in the step S08, and the method of packaging the battery in the step S09 can be carried out according to a conventional method in the art.
  • step S08 The battery cells in the battery can be square or other shapes according to the needs of different lithium batteries.
  • the preparation method of the lithium battery is mature in technology, the conditions are easy to control, and the qualification rate is high.
  • an embodiment of the present invention further provides a communication device, where the communication device includes a working module and a power supply module.
  • the power supply module supplies power to the working module, which includes the lithium battery described above, and the lithium battery may be one or more lithium batteries.
  • the working module operates using the power provided by the power supply module, for example, performing tasks such as accepting, exchanging, processing, storing, and transmitting related information.
  • the communication device can make any electronic device that requires electric energy such as a mobile phone or a notebook computer. In this way, since the power supply module of the communication device can supply power to the working module stably and continuously, the safety performance of the high communication device is improved, and the frequency of replacing the battery in the power supply module is reduced, and the operation cost of the communication device is reduced.
  • the functional polymer prepared is sufficiently dissolved in hydrazine, hydrazine-dimethylhydrazine guanamine DMF to prepare a functional polymer solution having a mass concentration of 3%, and the total mass of the slurry is added to a mass of 10%, and the diameter is 10 nm.
  • Carbon nanotubes with a length to diameter ratio of 150: 1 act as a conductive agent, and uniformly disperse carbon nanotubes in function by ultrasonic dispersion. In the polymer solution.
  • a nano-lithium iron silicate (LiFeSi0 4 ) positive electrode material having a particle size of 100 nm and having a particle size of 100 nm was added, and the above materials were sealed and ball-milled for 10 hours to obtain a lithium iron silicate slurry which was uniformly dispersed.
  • the slurry is dried by a centrifugal spray drying apparatus to remove the solvent, and the product particle size is controlled to be about 5 to 20 ⁇ m to obtain a composite silicate positive electrode material of lithium iron silicate coated with a functional polymer material.
  • the negative electrode slurry was uniformly coated on a 0.08 mm copper foil, and the copper foil was dried, rolled, and cut to obtain a negative electrode sheet having a size of 485 X 44 mm.
  • the galvanic sheet, the negative electrode sheet and the Celgard 2400 polypropylene porous film were laminated in the order of the positive electrode sheet/separator/negative electrode sheet, and then wound into a square battery core, and the electrolyte was injected into the battery aluminum in an amount of 3.6 g/Ah.
  • the shell is sealed and made into a square lithium-ion battery.
  • the constant pressure dropping funnel was added with 0.1% by mass of the total mass of the monomer, hydrazine-hydrazinyl bisacrylamide as a crosslinking agent, and stirring was continued for 2 hours to obtain a polymerization product.
  • the resulting polymer was suction filtered and dried in a vacuum oven to give the desired functional polymer, which was a translucent white solid.
  • the prepared functional polymer is sufficiently dissolved in acetone to prepare a polymer solution having a mass percentage concentration of 5%, and a carbon fiber having a total mass of 2% and an aspect ratio of 200:1 is added, and the carbon fibers are uniformly dispersed by ultrasonic dispersion. Dispersed in a functional polymer solution.
  • the slurry is dried by a centrifugal spray drying apparatus to control a product particle size of about 5 to 20 ⁇ m to obtain a composite silicate positive electrode material of lithium iron silicate coated with a functional polymer material.
  • a positive electrode was prepared in the same manner as in Example 1.
  • a negative electrode was prepared in the same manner as in Example 1.
  • a potassium ion battery was prepared by encapsulation in the same manner as in Example 1.
  • Example 3 A potassium ion battery was prepared by encapsulation in the same manner as in Example 1.
  • Example 4
  • a composite silicate positive electrode material, a lithium battery positive electrode and a lithium ion battery are prepared.
  • the nano carbon fiber replaces the carbon nanotube as a conductive agent, and the addition thereof is added.
  • the ratio is 2% of the total mass of the slurry.
  • a composite silicate positive electrode material, a lithium battery positive electrode and a lithium ion battery, which are coated with a functional polymer material are prepared.
  • Example 2 In the same manner as in Example 1, a composite silicate positive electrode material, a lithium battery positive electrode, and a lithium ion battery were prepared. The difference was that when preparing a lithium ion battery positive electrode material, nanometer lithium manganese silicate having a particle size of 200 nm was used ( LiMn.. 5 Fe.. 5 Si0 4 ) The cathode material replaces lithium iron silicate to form a uniformly dispersed lithium manganese silicate slurry, and finally a composite of lithium iron silicate coated with functional polymer material is obtained. Silicate positive electrode material, lithium battery positive electrode and lithium ion battery. Comparative example 1
  • the positive electrode material was prepared in the same manner as in Example 1, except that the lithium ion battery positive electrode material was directly used in the nanometer lithium iron silicate positive electrode material having a particle size of 100 nm as used in Examples 1 to 4.
  • a lithium ion battery was prepared in accordance with the method of preparing a lithium ion battery in Example 1. Comparative example 2
  • the positive electrode material was prepared in the same manner as in Example 1, except that the lithium ion battery positive electrode material was directly used as the nanometer lithium manganese silicate lithium positive electrode material having a particle size of 200 nm as used in Example 5.
  • a lithium ion battery was prepared in accordance with the method of preparing a lithium ion battery in Example 1. Performance Testing:
  • Capacity retention rate (discharge capacity after initial cycle 200 / initial discharge capacity) x 100 %, , (1)
  • the normal temperature and high temperature cycle performance test is carried out at a normal temperature of 25 ° C.
  • the high temperature cycle performance test is The test was carried out at 60 ° C, and the results are shown in Table 1 below:
  • the lithium ion batteries made of the lithium iron silicate positive electrode material coated with the functional polymer materials prepared in Examples 1 to 4 have a significantly better cycle capacity retention rate at both normal temperature and high temperature.
  • the lithium ion battery made of the ferromanganese silicate lithium cathode material coated with the functional polymer material prepared in Example 5 has a cycle capacity retention ratio which is also superior to that of the non-functional polymer material coated in Comparative Example 2.
  • the cycle capacity maintenance ratio of any of the lithium ion batteries of Examples 1 to 4 was significantly superior to that of the lithium ion batteries of Comparative Examples 1 and 2 as compared with any of the lithium ion batteries of Comparative Examples 1 and 2.
  • the batteries prepared in Examples 1 to 5 and Comparative Examples 1 to 2 were subjected to high-temperature storage performance tests.
  • testing method To: Put the battery on the charge and discharge test, first carry the constant current and constant voltage charge to the upper limit voltage of 3.5V with 1C current; after leaving for 10 minutes, discharge the current from 3.5V to 2.0V with the current of 1C, record the battery The discharge capacity is the initial capacity (discharge capacity); then the battery is placed in a high-temperature oven at 60 ° C for 7 days, and then discharged from 3.5 V to 2.0 V at a current of 1 C. The discharge capacity of the battery is recorded as the storage capacity (discharge capacity).
  • Capacity recovery capability recovery capacity / initial capacity, , , (3)
  • the composite silicate positive electrode material of the embodiment of the present invention is coated with a functional polymer containing an excessive metal ion chelating functional group to coat the nano silicate, and the chelation of the functional group can be used.
  • the impurity metal ions such as excessive metals eluted from the nanosilicate are trapped, thereby suppressing and preventing the elution and migration of the impurity metal ions. Therefore, the lithium battery of the embodiment of the invention can effectively inhibit and prevent the elution and migration of the impurity metal ions contained in the silicate from the positive electrode during charge and discharge cycle, storage and/or long-term recycling, thereby avoiding impurities.

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Abstract

本发明提供了一种复合硅酸盐正极材料及其制备方法、锂电池及其制备方法、锂电池正极及其制备方法和通信设备。该复合硅酸盐正极材料，包括通式为Li2MSiO4的纳米硅酸盐和导电剂以及包覆在所述纳米硅酸盐和导电剂表面的功能聚合物；其中，M为Co、Mn、Fe中的至少一种元素，所述功能聚合物含有过度金属离子螯合官能团。锂电池正极、锂电池和通信设备中均含有该复合硅酸盐正极材料。本发明复合硅酸盐正极材料通过官能团的螯合作用，能有效的捕获从该纳米硅酸盐中溶出的杂质金属离子，抑制和阻止该杂质金属离子的溶出和迁移，从而提高了该锂电池的安全性能和容量以及提高了锂电池的循环性能和高温储存性能，延长了该锂电池的使用寿命。

Description

复合硅酸盐正极材料、 锂电池及其制备方法、 通信设备 技术领域
本发明属于电池技术领域， 具体涉及一种复合硅酸盐正极材料及其制备方 法、 锂电池及其制备方法、 锂电池正极及其制备方法和通信设备。 背景技术
目前， 在全世界范围内， 锂离子电池越来越多地被用于通信、 交通、 计算 机以及其他各行各业中， 为人们的生活提供了无数便利。 并且随着生活水平的 提高， 人们更加关注资源、 环境、 安全等问题。 锂离子电池主要包含正极、 电 解液和负极三个部分。 锂离子电池的电极材料对于提高电池的电化学性能和降 低成本等方面至关重要， 由于负极材料多使用改性的石墨材料， 具有较高的比 容量。 因而， 当前锂离子电池电极材料的研究主要集中于优异正极材料的开发 上。
硅酸盐正极材料是一类新的聚阴离子型正极材料， 属于正交晶系， 所有阳 离子与氧原子均为四面体相关。 与磷酸源正极材料相比， 硅酸盐正极材料理论 上可以允许可逆的脱嵌两个锂， 因而具有更高的理论容量， 这使得硅酸盐材料 成为非常有吸引力的新型锂离子正极材料。
当前，传统硅酸盐正极材料的制备主要通过固相方法和液相法合成。其中， 固相方法为： 步骤 1)按比例将原料锂盐、 亚铁盐、 二氧化硅和添加剂混合， 其中 Li： Fe： Si的摩尔比为（1.9-2.1)： (0.95-1.05)： 1 , 添加剂的加入量为混合 物总质量的 1 ~ 30 %； 步骤 2) 将均匀混合的物料放入热处理设备中， 在流速为 100 ~ 5000ml/min的惰性气流保护中加热处理，升温速率为 1 °C/min ~ 20°C/min, 待热处理温度升至 300°C ~ 450°C时， 保持， 在该温度下加热 1 ~ 30小时， 然后 继续升温， 在 700°C ~ 900°C的范围内， 热处理 10小时〜 48小时， 然后緩慢降 至室温， 得到硅酸亚铁锂材料 。
液相法为： 将氢氧化锂和氧化硅加入水中同时将锰盐和铁盐混合物分散于 水中， 搅拌后移入水热釜中进行水热反应后， 水洗， 过滤， 烘干即得到目标产 物硅酸铁锰锂 -硅酸锰铁锂。
但不管采用上述的固相方法和液相法合成硅酸盐正极材料， 这些方法在制 备过程中由于混料不均或反应不均， 导致一定未反应的 Fe化合物杂质残留在产 物正极材料中。 另外这些方法都需要经过多次的高能球磨混合、 干燥、 烧结、 碎料等步骤， 操作时间长， 使用的金属设备、 管道、 原料及环境粉尘也会引入 一部分的 Fe、 Mn、 Cr、 Ni、 Zn、 Cu等金属杂质。 这些金属杂质的引入会对电 池的充放电不利而影响电池容量， 同时随着电池的充放电循环或储存， 会溶解 在电解液中形成金属阳离子， 或者电池的长时间循环使用过程中， 电解液发生 氧化或与水分反应产生氢氟酸 HF与硅酸盐正极材料反应， 使 Fe、 Mn等金属离 子溶出。 该溶出金属阳离子在电场的驱动下逐渐迁移到负极， 并最终在电池负 极和隔膜上沉积， 增大了电池的自放电， 严重的会刺穿隔膜， 造成电池短路， 发生安全事故。 技术问题 和阻止杂质金属离子的溶出和迁移的复合硅酸盐正极材料及其制备方法。
本发明实施例的另一目的在于提供一种含有该复合硅酸盐正极材料的锂电 池正极及其制备方法。
本发明实施例的又一目的在于提供一种含有锂电池正极的锂电池及其制备 方法。
本发明实施例的再一目的在于提供一种含有该锂电池的通信设备。 技术解决方案
为了实现上述发明目的， 本发明实施例的技术方案如下：
一种复合硅酸盐正极材料，包括通式为 Li2MSi04的纳米硅酸盐和导电剂以 及包覆在所述纳米硅酸盐和导电剂表面的功能聚合物； 其中， M为 Co、 Mn、 Fe中的至少一种元素， 所述功能聚合物含有过度金属离子螯合官能团。
优选地， 上述过度金属离子螯合官能团为 -CO-、 -COO-、 -CN、 -CON中的 至少一种基团。
优选地， 上述功能聚合物由摩尔比为 1:1 ~ 10的曱基丙烯酸曱酯单体与含 有上述过度金属离子螯合官能团的乙烯基单体共聚而成。
进一步优选地， 上述乙烯基单体为 CH2=CH(CH2)nCOR的酮， 其中 n为 0 或正整数， R为烷基； 或 /和为 CH2=CH(CH2)nCOOR的酮， 其中 n为 0或正整 数， R为烷基； 或 /和为含有 -CN基团的丙烯腈、 曱基丙烯腈、 偏二氰基乙烯中 的至少一种； 或 /和为含有 -CON-基团的丙烯酰胺、 丙烯酰胺双丙酮、 亚曱基丙 烯酰胺的至少一种。
优选地， 上述功能聚合物占所述复合硅酸盐正极材料总质量的 1 ~ 10%。 优选地， 上述导电剂占所述复合硅酸盐正极材料总质量的 1% ~ 3% 。
优选地， 上述复合硅酸盐正极材料的粒径为 5 ~ 20 μηι。
优选地， 上述导电剂为碳纳米管、 纳米碳纤维、 炭黑、 乙炔黑中的至少一 种。
一种如上所述的复合硅酸盐正极材料的制备方法， 包括如下步骤： 将上述含有过度金属离子螯合官能团的功能聚合物溶解在极性有机溶剂 中， 配制成功能聚合物溶液；
将所述导电剂、 通式为 Li2MSi04的纳米硅酸盐与所述功能聚合物溶液混 合， 然后经密封研磨， 得到含硅酸盐浆料；
将所述含硅酸盐浆料经喷雾干燥， 得到所述复合硅酸盐正极材料。
优选地， 上述功能聚合物按如下方法获取： 在无氧的条件下， 将甲基丙烯酸甲酯单体、 含有所述过度金属离子螯合官 能团的乙婦基单体、 引发剂和溶剂混合， 形成混合物；
将所述混合物在 40 ~ 80°C和搅拌下进行反应， 然后加入交联剂继续搅拌反 应， 得到聚合产物；
将所述聚合产物进行抽滤， 干燥， 得到所述功能聚合物。
进一步优选地， 上述引发剂加入量为甲基丙烯酸甲酯单体和乙婦基单体两 者总质量的 1% ~ 10%。
进一步优选地， 上述交联剂加入量为甲基丙烯酸甲酯单体和乙婦基单体两 者总质量 0.02% ~ 0.1%。
进一步优选地， 上述引发剂为油性引发剂或水溶性 )发剂。
进一步优选地， 上述交联剂为 Ν,Ν-亚甲基双丙烯酸酰胺、 二异氰酸酯、 过 氧化二异丙苯中的至少一种。
优选地， 上述功能聚合物溶液的质量百分比浓度为 1 ~ 10 %。
优选地， 上述导电剂、通式为 Li2MSi04的纳米硅酸盐与所述功能聚合物溶 液混合的方法为： 先将所述导电剂分散在与所述功能聚合物溶液混合， 然后加 入所述纳米硅酸盐进行混合。
优选地， 上述纳米硅酸盐的粒径为 50 ~ 200 nm。
以及， 一种锂电池正极， 包括集流体和结合在所述集流体上的含有正极材 料的活性层， 其特征在于： 所述正极材料上述的复合硅酸盐正极材料。
以及， 一种锂电池正极制备方法， 包括如下步骤：
将上述的复合硅酸盐正极材料与电极导电剂、 粘接剂混合并配制成正极浆 料；
将所述正极浆料涂覆在集流体上；
将所述涂覆有正极浆料的集流体进行干燥处理、 辊压、 裁剪， 得到锂电池 正极。
优选地， 上述复合硅酸盐正极材料、 电极导电剂和粘接剂的重量比为 100:(1~5):(1~5)。
优选地， 上述电极导电剂为炭黑、 碳纳米管、 碳纳米纤维、 乙炔黑中的至 少一种； 所述粘接剂为聚偏氟乙烯。
以及， 一种锂电池， 所述锂电池包括上述的锂电池正极。
优选地， 上述锂电池为电化学反应的化学锂电池。
进一步优选地， 上述电化学反应的化学锂电池为锂离子电池、 锂聚合物电 池、 锂 电池或锂空气电池。
以及， 一种锂电池制备方法， 包括如下步骤：
制备锂电池正极和负极， 所述锂电池正极由上述的锂电池正极制备方法制 备而成；
将所述锂电池正极、 隔膜、 所述锂电池负极依次层叠， 并进行卷绕， 制成 电池电芯；
将所述电芯装入电池壳体内， 再注入电解液， 密封， 制得锂电池。
本发明实施例还公开了一种通信设备， 该通信设备包括工作模块和供电模 块，所述供电模块包括上述的锂电池； 所述供电模块为所述工作模块提供电能， 所述工作模块使用所述供电模块提供的电能运行。 有益效果
上述实施例复合硅酸盐正极材料采用含有过度金属离子螯合官能团的功能 聚合物包覆纳米硅酸盐， 通过该官能团的螯合作用， 能有效的捕获从该纳米硅 酸盐中溶出的过度金属等杂质金属离子， 从而抑制和阻止该杂质金属离子的溶 出和迁移。
上述实施例锂电池正极由于含有上述复合硅酸盐正极材料， 又由于该复合 硅酸盐正极材料如上所述的能有效抑制和阻止该杂质金属离子的溶出和迁移， 因此， 该正极在工作过程中， 能有效抑制和阻止该硅酸盐中的杂质金属离子从 该正极中溶出和迁移。 上述实施例锂电池由于含有上述锂电池正极， 则该锂电池在充放电循环、 储存和 /或长时间循环使用过程中， 能有效抑制和阻止硅酸盐中含有的杂质金属 离子从正极中溶出和迁移， 从而避免了杂质金属离子迁移到负极并最终在负极 和隔膜上沉积以造成的电池的自放电、 刺穿隔膜而造成电池短路现象的发生， 从而提高了该锂电池的安全性能和容量以及提高了锂电池的循环性能和高温储 存性能， 延长了该锂电池的使用寿命。
将该锂电池用于上述实施例通信设备的供电模块中时， 则该通信设备的供 电模块能对工作模块稳定且持续的提供电能， 提高了高通信设备安全性能， 并 降低对供电模块中电池的更换频率， 降低了该通信设备运行的成本。
上述实施例中的复合硅酸盐正极材料、 锂电池正极和锂电池的制备方法工 艺筒单， 条件易控， 效率高， 适于工业化生产。 附图说明
下面将结合附图及实施例对本发明作进一步说明， 附图中：
图 1为本发明实施例复合硅酸盐正极材料的扫描电镜图；
图 2为本发明实施例复合硅酸盐正极材料的制备方法流程图；
图 3为本发明实施例锂电池正极的制备方法流程图；
图 4为本发明实施例锂电池的制备方法流程图。 本发明的实施方式
为了使本发明的目的、 技术方案及优点更加清楚明白， 以下结合附图及实 施例， 对本发明进行进一步详细说明。 应当理解， 此处所描述的具体实施例仅 仅用以解释本发明， 并不用于限定本发明。
本发明实例提供了一种能有效抑制和阻止杂质金属离子的溶出和迁移的复 合硅酸盐正极材料。 该复合硅酸盐正极材料， 包括通式为 Li2MSi04的纳米硅酸 盐和导电剂以及包覆在所述纳米硅酸盐和导电剂表面的功能聚合物； 其中， M 为 Co、 Mn、 Fe中的至少一种元素， 所述功能聚合物含有过度金属离子螯合官 能团。
具体地， 上述通式为 Li2MSi04的纳米硅酸盐可以采用现有方法制备而成， 如采用液相法制备获取。 由于硅酸盐理论上可以允许可逆的脱嵌两个锂， 因而 将该纳米硅酸盐作为正极材料具有更高的理论容量。 另外， 应该理解， 该纳米 硅酸盐的通式 Li2MSi04仅仅用来限定构成硅酸盐的基本元素，并不限定含有各 元素的含量的关系。 该通式为 Li2MSi04的纳米硅酸盐可以是硅酸铁锂 ( Li2FeSi04)、 硅酸锰锂（ Li2FeSi04)、 硅酸锰铁锂等硅酸盐正极材料。
上述导电剂的存在是为了增强该复合硅酸盐正极材料的导电性能。 该导电 剂优选为碳纳米管、 纳米碳纤维、 炭黑、 乙炔黑中的至少一种。 当然， 如果不 考虑导电剂的导电性能和成本， 该导电剂还可以选用本领域常用的导电剂。 另 外， 为了上述实施例复合硅酸盐正极材料具有优异的导电性能， 该导电剂优选 占该复合硅酸盐正极材料总质量的 1% ~ 3% 。
上述功能聚合物通过其含有的过度金属离子螯合官能团能有效捕获被其包 覆的上述纳米硅酸盐中含有的杂质金属离子， 抑制和阻止杂质金属离子迁移和 溶出该复合硅酸盐正极材料之外。 作为本发明的优选实施例， 上述功能聚合物 含有的过度金属离子螯合官能团为 -CO-、 -COO-、 -CN、 -CON中的至少一种基 团。 该优选地过度金属离子螯合官能团更有能有效的螯合过度金属杂质离子， 抑制和阻止杂质离子的迁移和溶出。 当然， 如果不考虑过度金属离子螯合官能 团对杂质金属离子的螯合效果， 则该过度金属离子螯合官能团还可以是本领域 其他的能与过度金属离子发生螯合的官能团。
其中， 上述功能聚合物优选按照如下方法摩尔比为 1 : 1 ~ 10的曱基丙烯酸 曱酯单体与含有所述过度金属离子螯合官能团的乙烯基单体共聚而成。
作为优选实施例， 该功能聚合物按如下方法获取：
步骤（1 )： 在无氧的条件下， 将引发剂、 摩尔比为 1 : 1 ~ 10的曱基丙烯酸 曱酯单体和含有所述过度金属离子螯合官能团的乙烯基单体以及溶剂混合， 形 成混合物；
步骤（ 2 ) ： 将所述步骤（ 1 ) 中的混合物在 40 ~ 80 °C和搅拌下进行反应， 然后加入交联剂继续搅拌反应， 得到聚合产物；
步骤（3 ) ： 将步骤（2 ) 中的聚合产物进行抽滤， 干燥处理， 得到所述功 能聚合物。
具体地， 上述步骤（ 1 )中所述溶剂可根据反应单体的溶解性质选择相应的 有机溶剂或去离子水， 溶剂加入量为曱基丙烯酸曱酯单体和乙婦基单体两者总 质量的 5 ~ 10倍。 引发剂可根据所选溶剂来选择油性引发剂 （如过氧化苯曱酰 BPO、 偶氮二异丁腈 AIBN等）或水溶性引发剂 （如过氧化氢、 过硫酸铵等）。 其中， 引发剂加入量为曱基丙烯酸曱酯单体和乙烯基单体两者总质量的 1% ~ 10%。 该乙烯基单体中的过度金属离子螯合官能团为 -CO-、 -COO-、 -CN、 -CON 中的至少一种基团。 另外， 该乙烯基单体中含有的过度金属离子螯合官能团可 以是只含有一种或一个该官能团，也可以同时含有两个或两种以上的该官能团， 也就是说在本发明实施例中， 对该乙烯单体中含有的过度金属离子螯合官能团 的种类和数量均没有特别的限定。 因此， 该乙烯基单体具体为 CH2=CH(CH2)nCOR 的酮， 其中 n 为 0 或正整数， R 为烷基； 或 /和为 CH2=CH(CH2)nCOOR的酮， 其中 n为 0或正整数， R为烷基； 或 /和为含有 -CN 基团的丙烯腈、 曱基丙烯腈、 偏二氰基乙烯中的至少一种； 或 /和为含有 -CON- 基团的丙烯酰胺、 丙烯酰胺双丙酮、 亚曱基丙烯酰胺的至少一种。
该步骤（ 1 )中的无氧条件可以是真空的无氧条件， 也可以是充满氮气的无 氧条件。
该步骤（ 2 )中的交联剂加入量为曱基丙烯酸曱酯单体和乙婦基单体两者总 质量或曱基丙烯酸曱酯单体和乙婦基单体总质量的 0.02% ~ 0.1%。 其中， 交联 剂为 Ν,Ν-亚曱基双丙烯酸酰胺、 二异氰酸酯、 过氧化二异丙苯中的至少一种。 待步骤（ 1 ) 中的混合物搅拌反应的时间为 0.5 ~ 24小时， 加入交联剂反应的时 间为 2 ~ 12分钟。 该步骤（3 ) 中的抽滤， 干燥处理均可以按照本领域常规的方式处理即可。 为了使得上述实施例复合硅酸盐正极材料具有一定含量的过度金属离子螯 合官能团， 以实现更好的螯合纳米硅酸盐中的杂质金属离子， 同时不影响锂离 子的传递， 上述功能聚合物的含量优选占所述复合硅酸盐正极材料总质量的 1 ~ 10%, 更优选为 2 ~ 5%。
优选地，上述复合硅酸盐正极材料的粒径优选控制在 5 ~ 20 μηι之间，该优 选粒径范围的复合硅酸盐正极材料具有良好的导电性能和较高的容量。 当然， 如果不考虑获得最佳的导电性能和容量， 该粒径还可以是其他尺寸。
另外， 上述实施例复合硅酸盐正极材料中的功能聚合物包覆纳米硅酸盐和 导电剂的方式可以但不仅仅是一下几种情况：
作为具体的一实施例， 上述功能聚合物包覆在纳米硅酸盐外表面， 其中， 导电剂参杂在纳米硅酸盐之中。 其中， 功能聚合物包覆可以是全包覆或部分包 或作为具体的一实施例， 上述功能聚合物分别包覆在纳米硅酸盐、 导电剂 外表面上。 其中， 功能聚合物包覆可以是全包覆或部分包覆。
或作为具体的一实施例， 上述功能聚合物为上述两具体实施例中复合硅酸 盐正极材料的混合物。
由上所述， 上述实施例复合硅酸盐正极材料采用含有过度金属离子螯合官 能团的功能聚合物包覆纳米硅酸盐， 通过该官能团的螯合作用， 能有效的捕获 从该纳米硅酸盐中溶出的过度金属等杂质金属离子， 从而抑制和阻止该杂质金 属离子的溶出和迁移。 该导电剂的存在能有效的改善该复合硅酸盐正极材料的 导电性能。 因此， 该复合硅酸盐正极材料能有效捕获从该纳米硅酸盐中溶出的 过度金属等杂质金属离子， 抑制和阻止该杂质金属离子的溶出和迁移， 其容量 高， 导电性好。 将上述实施例复合硅酸盐正极材料采用 日本 JEOL 的 JSM-5610LV型扫描电子显微镜放大 5000倍进行观测， 得到 SEM图 1。 由图 1 可进一步确认， 本发明实施例复合硅酸盐正极材料中的硅酸盐表面被导电聚合 物层均匀包覆。
本发明还提供了上述复合硅酸盐正极材料的一种制备方法。 该复合负电极 制备方法工艺流程请参见图 2, 其包括如下步骤：
步骤 S01. 配制功能聚合物溶液：将上文所述的含有过度金属离子螯合官能 团的功能聚合物溶解在极性有机溶剂中， 配制成功能聚合物溶液；
步骤 S02. 制备含硅酸盐浆料： 将上文所述的导电剂、 通式为 Li2MSi04的 纳米硅酸盐与步骤 S01配制的功能聚合物溶液混合， 然后经密封研磨， 得到含 硅酸盐浆料；
步骤 S03. 将含硅酸盐浆料喷雾干燥： 将步骤 S02配制的含硅酸盐浆料经 喷雾干燥， 得到所述复合硅酸盐正极材料。
具体地， 上述步骤 S01中的含有过度金属离子螯合官能团的功能聚合物及 其制备方法如同上文所述， 为了节约篇幅， 在此不再赘述。 极性有机溶剂优选 为 N -二曱基曱酰胺（DMF ) 、 丙酮中的一种或两种混合物， 当然还可以选用 能有效溶解功能聚合物的其他常用的极性有机溶剂。 在该步骤 S01中的功能聚 合物溶液的质量百分比浓度优选为 1 ~ 10 %。
上述步骤 S02中的通式为 Li2MSi04的纳米硅酸盐、导电剂以及导电剂、 纳 米硅酸盐与功能聚合物三者的添加量的比例均如同上文所述， 为了节约篇幅， 在此不再赘述。 作为优选实施例， 导电剂、 纳米硅酸盐与功能聚合物三者混合 的方法为： 先将导电剂分散在与功能聚合物溶液混合， 然后加入所述纳米硅酸 盐进行混合； 其中， 该纳米硅酸盐的粒径为 50 ~ 200 nm。 这样使得各组分均匀 分散。 为了使得导电剂、 纳米硅酸盐均匀分散， 在加入导电剂、 纳米硅酸盐的 过程中， 可以结合超声处理的步骤， 使得导电剂、 纳米硅酸盐， 特别是导电剂 在浆料均勾分散， 且使得浆料稳定， 不至于发生分层。
该步骤 S02中的密封研磨优选再用球磨机进行密封球磨， 为了使得各组分 充分分散并将导电剂与纳米硅酸盐的粒径控制在较小的范围， 该密封研磨的时 间优选为 8 ~ 10小时。 当然， 也可以采用本领域公知其他研磨方式进行密封研 磨。
上述步骤 S03中的喷雾干燥是为了获得干燥的且上述功能聚合物包覆纳米 硅酸盐的复合硅酸盐正极材料。 为了获得良好颗粒及粒径的复合硅酸盐正极材 料， 应该对喷雾干燥的工艺条件进行调整， 使得最后获得粒径优选为 5 ~ 20 μηι 的复合硅酸盐正极材料。
该复合硅酸盐正极材料制备方法将功能聚合物包覆在纳米硅酸盐和导电剂 表面， 以形成包覆结构的复合硅酸盐正极材料。 从而使得该复合硅酸盐正极材 料具有如上文所述的能有效的捕获从该纳米硅酸盐中溶出的过度金属等杂质金 属离子， 从而抑制和阻止该杂质金属离子的溶出和迁移的优异功能。 该方法制 备方法筒单， 条件易控， 效率高， 适于工业化生产。
本发明进一步的提供了一种锂电池正极， 其包括集流体和结合在该集流体 上的含有正极材料的活性层， 其中， 该正极材料为上文所述的复合硅酸盐正极 材料； 集流体可以选用本领域常用的集流体， 如铝箔等。 这样， 该锂电池正极 由于含有上文所述的复合硅酸盐正极材料， 又由于该复合硅酸盐正极材料如上 所述的能有效抑制和阻止该杂质金属离子的溶出和迁移， 因此， 该锂电池正极 在工作过程中， 能有效抑制和阻止该硅酸盐中的杂质金属离子从该正极中溶出 和迁移。
相应地， 本发明进一步的提供了一种锂电池正极。 该锂电池正极制备方法 工艺流程请参见图 3 , 其包括如下步骤：
步骤 S04. 配制正极浆料： 将上文所述的复合硅酸盐正极材料与电极导电 剂、 粘接剂混合并配制成正极浆料；
步骤 S05. 将步骤 S04配制的正极浆料涂覆在集流体上；
步骤 S06. 集流体的干燥、 辊压和裁剪处理： 将经步骤 S05处理的涂覆有 正极浆料的集流体进行干燥处理、 辊压、 裁剪， 得到锂电池正极。
具体地， 上述步骤 S04复合硅酸盐正极材料、 电极导电剂和粘接剂的重量 比优选为 100:(1~5):(1~5), 更优选为 100:3:3。 上述电极导电剂为炭黑、 碳纳米 管、 纳米碳纤维、 乙炔黑中的至少一种； 所述粘接剂为聚偏氟乙烯。 当然， 该 电极导电剂、 粘接剂还可以选用本领域常用的其他物质。
上述步骤 S05中涂覆正极浆料的方式和步骤 S06对集流体进行干燥处理、 辊压、 裁剪的方式均可以采用本领域常用的方法即可。
该锂电池正极制备方法只需将含有上文所述的复合硅酸盐正极材料的正极 浆料涂覆在集流体上， 再经干燥、 辊压、 裁剪处理即可， 该方法筒单， 条件易 控， 合格率和生产效率高。
本发明实例还提供了一种锂电池， 该锂电池包括上文所述的锂电池正极。 作为优选实施例， 该锂电池为电化学反应的化学锂电池。 具体地， 该电化 学反应的化学锂电池为锂离子电池、 锂聚合物电池、 锂硫电池或锂空气电池。
这样， 该锂电池由于含有上文所述的锂电池正极， 则该锂电池在充放电循 环、 储存和 /或长时间循环使用过程中， 能有效抑制和阻止硅酸盐中含有的杂质 金属离子从正极中溶出和迁移， 从而避免了杂质金属离子迁移到负极并最终在 负极和隔膜上沉积以造成的电池的自放电、 刺穿隔膜而造成电池短路现象的发 生， 从而提高了该锂电池的安全性能和容量以及提高了锂电池的循环性能和高 温储存性能， 延长了该锂电池的使用寿命。
相应地， 本发明实施例进一步的提供了一种锂电池制备方法。 该锂电池制 备方法工艺流程请参见图 4, 其包括如下步骤：
步骤 S07. 制备锂电池正极和负极，其中，该锂电池正极由上文所述的锂电 池正极制备方法制备而成；
步骤 S08. 制备电池电芯： 将步骤 S07制备电池正极和负极按照锂电池正 极 /隔膜 /锂电池负层叠方式依次层叠， 并进行卷绕， 制成电池电芯；
步骤 S09. 封装电池： 将所述电芯装入电池壳体内， 再注入电解液， 密封， 制得锂电池。
具体地， 上述步骤 S07中负极的制备、 步骤 S08中的电池电芯的制备和步 骤 S09中的封装电池方法均可以按照本领域常规的方法制备即可。其中步骤 S08 中的电池电芯可以方形或其他根据不同锂电池需要的形状。 这样， 该锂电池的 制备方法工艺技术成熟， 条件易控， 合格率高。
另外， 本发明实施例还提供了一种通信设备， 该通信设备包括工作模块和 供电模块。 其中， 供电模块为工作模块提供电能， 其包括上文所述的锂电池， 该锂电池可以是一个或两个以上的锂电池。 放供电模块包括两个以上的锂电池 时， 该锂电池可以根据工作模块所需电能的需要， 以并联或串联或并串联接。 该工作模块使用供电模块提供的电能运行， 例如执行相关信息的接受、 交换、 处理、 储存、 发射等任务。 该通信设备可以使手机、 笔记本电脑等任意一种需 要电能的电子设备。 这样， 由于该通信设备的供电模块能对工作模块稳定且持 续的提供电能， 提高了高通信设备安全性能， 并降低对供电模块中电池的更换 频率， 降低了该通信设备运行的成本。
以下通过多个实施例来举例说明上述复合硅酸盐正极材料及其制备方法、
实施例 1
功能聚合物材料的制备：
在反应容器中按摩尔比 1 :2的比例加入曱基丙烯酸曱酯 MMA单体和丙烯晴 AN单体， 加入单体总摩尔数 2倍的溶剂， 加入单体总质量 4%的引发剂过氧化苯 曱酞 BPO, 形成混合物。 将所述混合物搅拌均匀后密封反应容器， 加热并恒温 至 70°C ,搅拌反应 40分钟后，通过恒压滴液漏斗加入单体总质量的 0.05%的 Ν,Ν- 亚曱基双丙烯酸酰胺作为交联剂， 继续搅拌 3.5小时， 得到聚合产物。 将所制得 的聚合物进行抽滤， 并在真空干燥箱中烘干得到所需的功能聚合物， 所述功能 聚合物为淡黄色固体。
复合硅酸盐正极材料的制备：
将制备的该功能聚合物充分溶解在 Ν, Ν-二曱基曱酞胺 DMF中制得质量百 分比浓度为 3%的功能聚合物溶液， 加入浆料总质量 1%的、 直径为 10 nm、 长径 比为 150: 1的碳纳米管作为导电剂， 并通过超声分散将碳纳米管均匀分散在功能 聚合物溶液中。 加入浆料总质量 50%的、 颗粒粒径大小为 lOOnm的纳米硅酸铁 锂 (LiFeSi04)正极材料， 将上述材料一起密封球磨 10小时，得到均勾分散的纳米 硅酸铁锂浆料。 将该浆料通过离心喷雾干燥设备烘干除去溶剂， 控制产物颗粒 大小约为 5 ~ 20微米，得到由功能聚合物材料包覆的硅酸铁锂的复合硅酸盐正极 材料。
锂离子电池的制备：
锂电池正极的制备： 按复合硅酸盐正极材料： 电极导电剂碳黑 super-P:粘结 剂聚偏氟乙烯 PVDF： N-曱基吡咯烷酮 NMP = 100:3:3: 150(质量比）的比例混合 后， 在真空高速搅拌机中搅拌 4 ~ 8小时形成均勾的正极浆料， 将该正极浆料均 匀地涂覆在 0.016mm铝箔上， 将铝箔烘干、 辊压、 裁切制得尺寸为 485 x 44 mm 的正极片。
锂电池负极的制备： 按石墨：梭曱基纤维素钠 CMC:丁苯橡胶 SBR^ = 100:6:7:120的质量比混合后， 在真空高速搅拌机中搅拌制得均匀的负极浆料， 将该负极浆料均勾地涂布在 0.08mm的铜箔上， 将铜箔烘干、 辊压、 裁切制得尺 寸为 485 X 44 mm的负极片。
分别将正极片、 负极片与 Celgard2400聚丙烯多孔膜按照正极片 /隔膜 /负极 片的层叠次序依次层叠后卷绕成一个方形电池极芯，将电解液以 3. 6g/Ah的量注 入电池铝壳中， 密封， 制成方形锂离子电池。 其中电解液为六氟磷酸锂溶解在 碳酸乙烯酯：碳酸二乙烯酯：碳酸二曱酯 = 1： 1： 1 (质量比)的混合溶剂中形成的浓 度为 lmol/L的溶液。 实施例 2
功能聚合物材料的制备：
在反应容器中按摩尔比 1 :2的比例加入曱基丙烯酸曱酯 MMA和乙酸乙烯酯 VAc加入单体总摩尔数 2倍的溶剂， 加入单体总质量 3%的引发剂偶氮二异丁腈 AIBN, 形成混合物。 将所述混合物搅拌均匀后， 通入氮气 30分钟以除去反应体 系中的氧， 然后密封反应容器， 加热并恒温至 80°C , 搅拌反应 20分钟后， 通过 恒压滴液漏斗加入单体总质量的 0.1%的 Ν,Ν-亚曱基双丙烯酸酰胺作为交联剂， 继续搅拌 2小时， 得到聚合产物。 将所制得的聚合物进行抽滤， 并在真空干燥箱 中烘干得到所需的功能聚合物， 所述功能聚合物为半透明白色固体。
复合硅酸盐正极材料的制备：
将制备的功能聚合物充分溶解在丙酮中制得质量百分比浓度为 5%的聚合 物溶液， 加入浆料总质量 2%的、 长径比为 200: 1的碳纤维， 并通过超声分散将 碳纤维均匀分散在功能聚合物溶液中。 加入浆料总质量 50%的、 颗粒粒径大小 为 lOOnm的纳米硅酸铁锂 (LiFeSi04)正极材料， 将上述材料一起密封球磨 8小时， 得到均匀分散的硅酸铁锂浆料。 将该浆料通过离心喷雾干燥设备烘干， 控制产 物颗粒大小约为 5 ~ 20微米，得到由功能聚合物材料包覆的硅酸铁锂的复合硅酸 盐正极材料。
锂离子电池的制备：
锂电池正极的制备： 采用与实施例 1中相同的方式， 制备正极。
锂电池负极的制备： 采用与实施例 1中相同的方式， 制备负极。
锂离子电池的封装： 采用与实施例 1中相同的方式进行封装，制备钾离子电 池。 实施例 3
采用与实施例 1相同的方式，制备复合硅酸盐正极材料、锂电池正极及锂离 子电池， 不同的是， 制备功能聚合物材料时， 增加了一种丙烯酞胺 AM单体， 三种单体加入的摩尔比为 MMA:AN:AM = 3:4:1 , 最终制得由功能聚合物材料包 覆的硅酸铁锂的复合硅酸盐正极材料、 锂电池正极及锂离子电池。 实施例 4
采用与实施例 1相同的方式，制备复合硅酸盐正极材料、锂电池正极及锂离 子电池， 不同的是， 制备复合硅酸盐正极材料时， 纳米碳纤维替代碳纳米管作 为导电剂， 其加入比例为浆料总质量 2%。 最终制得由功能聚合物材料包覆的硅 酸铁锂的复合硅酸盐正极材料、 锂电池正极及锂离子电池。 实施例 5
采用与实施例 1相同的方式，制备复合硅酸盐正极材料、锂电池正极及锂离 子电池， 不同的是， 制备锂离子电池正极材料时， 用颗粒大小为 200nm的纳米 硅酸锰铁锂 （LiMn。.5Fe。.5Si04)正极材料替代纳米硅酸铁锂， 形成均匀分散的硅 酸锰铁锂浆料， 最终制得由功能聚合物材料包覆的硅酸锰铁锂的复合硅酸盐正 极材料、 锂电池正极及锂离子电池。 对比例 1
锂离子电池正极的制备：
按照实施例 1中制备正极的方法， 不同的是，锂离子电池正极材料直接采用 实施例 1至 4中所使用的颗粒大小 100 nm的纳米硅酸铁锂正极材料。
锂离子电池的制备：
按照实施例 1中制备锂离子电池的方法制备锂离子电池。 对比例 2
锂离子电池正极的制备：
按照实施例 1中制备正极的方法， 不同的是，锂离子电池正极材料直接采用 实施例 5中所使用的颗粒大小为 200nm的纳米硅酸锰铁锂正极材料。
锂离子电池的制备：
按照实施例 1中制备锂离子电池的方法制备锂离子电池。 性能测试：
下面是针对上述各实施例和对比例制备的锂离子电池进行性能测试， 测试 方法如下：
(1)常温和高温循环性能测试 体测试方法为： 将电池放在充放电测试拒上， 首先以 1C的电流进行恒流恒压充 电至上限电压 3.5V, 并搁置 10分钟后， 再以 1C的电流从 3. 5V放电至 2. 0V, 记 录电池的初始放电容量；然后再重复上述充放电步骤 200次后，记录电池循环 200 次后的放电容量， 按下述公式（1 )计算 200次循环容量维持率
容量维持率 =(循环 200次后的放电容量 /初始放电容量）x 100 %、 、 、 (1) 该常温和高温循环性能测试是在常温 25 °C环境下进行测试， 高温循环性能 测试是在 60°C环境下进行测试， 所得结果如下述表 1所示：
Figure imgf000019_0001
常温 25 C 1¾温 60 C
电池
200次循环容量维持率（％ ) 200次循环容量维持率 （％) 实施例 1 95.9 91.4
实施例 2 95.4 91.3
实施例 3 94.9 90.8
实施例 4 95.0 91.1
实施例 5 94.1 91.0
对比例 1 85.6 79.8
对比例 2 87.4 82.1
由该表 1可知，实施例 1至 4中制备的经过功能聚合物材料包覆的硅酸铁锂正 极材料制成的锂离子电池无论在常温还是高温下的循环容量维持率均明显优于 对比例 1中未经功能聚合物材料包覆的硅酸铁锂正极材料制成的锂离子电池。实 施例 5中制备的经过功能聚合物材料包覆的硅酸锰铁锂正极材料制成的锂离子 电池的循环容量维持率也明显优于对比例 2中未经功能聚合物材料包覆的硅酸 锰铁锂正极材料制成的锂离子电池。 将实施例 1至 4中任一锂离子电池的循环容 量维持率与对比例 1、 2中任一锂离子电池相比， 均明显优于对比例 1、 2中的锂 离子电池。
(2)高温储存性能测试
将实施例 1至 5及对比例 1至 2制得的电池进行高温存储性能测试。 测试方法 为： 将电池放在充放电测试拒上， 先以 1C的电流进行恒流恒压充电至上限电压 3.5V; 搁置 10分钟后， 再以 1C的电流从 3.5V放电至 2.0V, 记录电池的放电容量 为初始容量（放电容量）； 然后将电池放置于 60 °C高温烘箱中储存 7天后， 再以 1C的电流从 3.5V放电至 2.0V, 记录电池的放电容量为储存容量（放电容量） ； 最后再重复上述充放电过程 3次后， 记录最后一次的放电容量， 即为恢复容量。 按公式 (2)(3)计算容量保持能力、 容量恢复能力， 所得结果如下述表 2所示： 容量保持能力 =储存容量 /初始容量、 、 、 （2)
容量恢复能力 =恢复容量 /初始容量、 、 、 （3)
Figure imgf000020_0001
Figure imgf000020_0002
由该表 2可知，实施例 1至 4中制备的经过功能聚合物材料包覆的硅酸铁锂正 极材料制成的锂离子电池高温储存容量保持和恢复能力均明显优于对比例 1中 未经功能聚合物材料包覆的硅酸铁锂正极材料制成的锂离子电池。实施例 5中制 备的经过功能聚合物材料包覆的硅酸锰铁锂正极材料制成的锂离子电池的高温 储存容量保持和恢复能力也明显优于对比例 2中未经功能聚合物材料包覆的硅 酸锰铁锂正极材料制成的锂离子电池。
综合表 1、 2可知， 本发明实施例复合硅酸盐正极材料采用含有过度金属离 子螯合官能团的功能聚合物包覆纳米硅酸盐， 通过该官能团的螯合作用， 能有 效的捕获从该纳米硅酸盐中溶出的过度金属等杂质金属离子， 从而抑制和阻止 该杂质金属离子的溶出和迁移。 因此，使得本发明实施例锂电池在充放电循环、 储存和 /或长时间循环使用过程中， 能有效抑制和阻止硅酸盐中含有的杂质金属 离子从正极中溶出和迁移， 从而避免了杂质金属离子迁移到负极并最终在负极 和隔膜上沉积以造成的电池的自放电、 刺穿隔膜而造成电池短路现象的发生， 从而提高了该锂电池的安全性能和容量以及提高了锂电池的循环性能和高温储 存性能， 延长了该锂电池的使用寿命。 以上所述仅为本发明的较佳实施例而已， 并不用以限制本发明， 凡在本发 明的精神和原则之内所作的任何修改、 等同替换和改进等， 均应包括在本发明 的保护范围之内。

Claims

权 利 要 求 书
1. 一种复合硅酸盐正极材料， 包括通式为 Li2MSi04的纳米硅酸盐和导电 剂以及包覆在所述纳米硅酸盐和导电剂表面的功能聚合物； 其中， M 为 Co、 Mn、 Fe中的至少一种元素， 所述功能聚合物含有过度金属离子螯合官能团。
2. 如权利要求 1所述的复合硅酸盐正极材料， 其特征在于： 所述过度金属 离子螯合官能团为 -CO-、 -COO-、 -CN、 -CON中的至少一种基团。
3. 如权利要求 1或 2所述的复合硅酸盐正极材料， 其特征在于： 所述功能 聚合物由摩尔比为 1:1 ~ 10的曱基丙烯酸曱酯单体与含有所述过度金属离子螯 合官能团的乙烯基单体共聚而成。
4. 如权利要求 3所述的复合硅酸盐正极材料， 其特征在于： 所述乙婦基单 体为 CH2=CH(CH2)nCOR的酮， 其中 n为 0或正整数， R为烷基； 或 /和
为 CH2=CH(CH2)nCOOR的酮， 其中 n为 0或正整数， R为烷基； 或 /和 为含有 -CN基团的丙烯腈、 曱基丙烯腈、 偏二氰基乙烯中的至少一种； 或 / 和
为含有 -CON-基团的丙烯酰胺、 丙烯酰胺双丙酮、 亚曱基丙烯酰胺的至少 一种。
5. 如权利要求 1或 2所述的复合硅酸盐正极材料， 其特征在于： 所述功能 聚合物占所述复合硅酸盐正极材料总质量的 1 ~ 10%。
6. 如权利要求 1或 2所述的复合硅酸盐正极材料， 其特征在于： 所述导电 剂占所述复合硅酸盐正极材料总质量的 1% ~ 3% 。
7. 如权利要求 1或 2所述的复合硅酸盐正极材料， 其特征在于： 所述复合 硅酸盐正极材料的粒径为 5 ~ 20 μηι。
8. 如权利要求 1或 2所述的复合硅酸盐正极材料， 其特征在于： 所述导电 剂为碳纳米管、 纳米碳纤维、 炭黑、 乙炔黑中的至少一种。
9. 如权利要求 1 ~ 8任一所述的复合硅酸盐正极材料的制备方法， 其特征 在于， 包括如下步骤：
将所述含有过度金属离子螯合官能团的功能聚合物溶解在极性有机溶剂 中， 配制成功能聚合物溶液；
将所述导电剂、 通式为 Li2MSi04的纳米硅酸盐与所述功能聚合物溶液混 合， 然后经密封研磨， 得到含硅酸盐浆料；
将所述含硅酸盐浆料经喷雾干燥， 得到所述复合硅酸盐正极材料。
10. 如权利要求 9所述的复合硅酸盐正极材料的制备方法， 其特征在于， 所述功能聚合物按如下方法获取：
在无氧的条件下， 将曱基丙烯酸曱酯单体、 含有所述过度金属离子螯合官 能团的乙婦基单体、 引发剂和溶剂混合， 形成混合物；
将所述混合物在 40 ~ 80 °C和搅拌下进行反应， 然后加入交联剂继续搅拌反 应， 得到聚合产物；
将所述聚合产物进行抽滤， 干燥， 得到所述功能聚合物。
11. 如权利要求 10所述的复合硅酸盐正极材料的制备方法， 其特征在于： 所述引发剂加入量为曱基丙烯酸曱酯单体和乙烯基单体两者总质量的 1% ~ 10%。
12. 如权利要求 10所述的复合硅酸盐正极材料的制备方法， 其特征在于： 所述交联剂加入量为曱基丙烯酸曱酯单体和乙婦基单体两者总质量的 0.02% ~ 0.1%。
13. 如权利要求 10 ~ 12任一所述的复合硅酸盐正极材料的制备方法，其特 征在于： 所述引发剂为油性引发剂或水溶性引发剂。
14. 如权利要求 10 ~ 12任一所述的复合硅酸盐正极材料的制备方法，其特 征在于： 所述交联剂为 Ν,Ν-亚曱基双丙烯酸酰胺、 二异氰酸酯、 过氧化二异丙 苯中的至少一种。
15. 如权利要求 9 ~ 12任一所述的复合硅酸盐正极材料的制备方法， 其特 征在于： 所述功能聚合物溶液的质量百分比浓度为 1 ~ 10 %。
16. 如权利要求 9 ~ 12任一所述的复合硅酸盐正极材料的制备方法， 其特 征在于， 所述导电剂、通式为 Li2MSi04的纳米硅酸盐与所述功能聚合物溶液混 合的方法为： 先将所述导电剂分散在与所述功能聚合物溶液混合， 然后加入所 述纳米硅酸盐进行混合。
17. 如权利要求 9 ~ 12任一所述的复合硅酸盐正极材料的制备方法， 其特 征在于： 所述纳米硅酸盐的粒径为 50 ~ 200 nm。
18. 一种锂电池正极， 包括集流体和结合在所述集流体上的含有正极材料 的活性层，其特征在于： 所述正极材料为如权利要求 1 ~ 8任一所述的复合硅酸 盐正极材料。
19. 一种锂电池正极制备方法， 包括如下步骤：
将权利要求 1 ~ 8任一所述的复合硅酸盐正极材料与电极导电剂、粘接剂混 合并配制成正极浆料；
将所述正极浆料涂覆在集流体上；
将所述涂覆有正极浆料的集流体进行干燥处理、 辊压、 裁剪， 得到锂电池 正极。
20. 如权利要求 19所述的锂电池正极制备方法， 特征在于： 所述复合硅酸 盐正极材料、 电极导电剂和粘接剂的重量比为 100:(1~5):(1~5)。
21. 如权利要求 19或 20所述的锂电池正极制备方法， 特征在于： 所述电 极导电剂为炭黑、 碳纳米管、 碳纤维、 乙炔黑中的至少一种； 所述粘接剂为聚偏氟乙烯。
22. 一种锂电池， 其特征在于， 所述锂电池包括权利要求 18所述的锂电池 正极。
23. 如权利要求 22所述的锂电池， 特征在于： 所述锂电池为电化学反应的 化学锂电池。
24. 如权利要求 23所述的复合负电极的制备方法， 其特征在于， 所述电化 学反应的化学锂电池为锂离子电池、 锂聚合物电池、 锂硫电池或锂空气电池。
25. 一种锂电池制备方法， 包括如下步骤：
制备锂电池正极和负极，所述锂电池正极由权利要求 19 ~ 21任一所述的锂 电池正极制备方法制备而成；
将所述锂电池正极、 隔膜、 所述锂电池负极依次层叠， 并进行卷绕， 制成 电池电芯；
将所述电芯装入电池壳体内， 再注入电解液， 密封， 制得锂电池。
26. 一种通信设备， 包括工作模块和供电模块， 所述供电模块包括权利要求 22 所述的锂电池； 所述供电模块为所述工作模块提供电能， 所述工作模块使用所 述供电模块提供的电能运行。
PCT/CN2013/073380 2012-09-18 2013-03-28 复合硅酸盐正极材料、锂电池及其制备方法、通信设备 WO2014044039A1 (zh)

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