WO2014075416A1 - 富锂正极材料、锂电池正极和锂电池 - Google Patents

富锂正极材料、锂电池正极和锂电池 Download PDF

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WO2014075416A1
WO2014075416A1 PCT/CN2013/073371 CN2013073371W WO2014075416A1 WO 2014075416 A1 WO2014075416 A1 WO 2014075416A1 CN 2013073371 W CN2013073371 W CN 2013073371W WO 2014075416 A1 WO2014075416 A1 WO 2014075416A1
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lithium
positive electrode
rich
salt
cathode material
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PCT/CN2013/073371
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English (en)
French (fr)
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陈朝辉
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华为技术有限公司
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Priority to KR1020157001726A priority Critical patent/KR20150023856A/ko
Priority to JP2015524605A priority patent/JP2015529943A/ja
Publication of WO2014075416A1 publication Critical patent/WO2014075416A1/zh
Priority to US14/587,603 priority patent/US20150118563A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
    • 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
    • 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
    • H01M4/1315—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx containing halogen atoms, e.g. 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • 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
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/30—Batteries in portable systems, e.g. mobile phone, laptop
    • 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

  • Lithium-rich cathode material Lithium-rich cathode material, lithium battery anode and lithium battery
  • the invention belongs to the technical field of batteries, and particularly relates to a lithium-rich positive electrode material, a lithium battery positive electrode and a lithium battery.
  • lithium-ion batteries are considered to be the next generation of high-efficiency portable portable chemical power sources due to their high energy density, long cycle life, light weight, and no pollution. It has been widely used in digital cameras, smart phones, notebook computers, etc. With the further increase in the energy density of lithium-ion batteries, their applications will gradually be applied to electric vehicles (electric bicycles, electric vehicles, hybrid vehicles), power grids and other large-scale energy storage areas.
  • cathode materials lithium cobalt oxide (LCO), lithium manganate (LMO), lithium iron phosphate (LFP), ternary (NCM), etc., but these cathode materials have a specific capacity of ⁇ 160 mAh/g.
  • the lithium-rich solid solution of the existing layered-layered structure has a high theoretical specific capacity, but the capacity itself is rapidly degraded due to the instability of the material itself under high voltage conditions.
  • the Layered-rocksalt structure lithium-rich solid solution also has disadvantages: the use of a layered-rocksalt structure lithium-rich solid solution material for a lithium ion battery (compared to the conventional Layered-Layered solid solution xLi 2 Mn0 3 (lx)LiM0 2 , 0 ⁇ x ⁇ 1 )
  • the decrease in the Li content reduces the discharge capacity of the material.
  • A. Manthiram et al. synthesized a new lithium-rich solid solution Layered-Spinel structure: xLi[Lio.2Mno.6Nio.i 7 Coo.o3]0 2 -(lx)Li[Mn 1 . 5 Nio.452Coo.o75] 04, 0 ⁇ ⁇ ⁇ 1 , and this new structure is used for the positive electrode material of lithium ion battery, and the stability of the Spinel structure is used to exhibit excellent first charge and discharge efficiency and cycle performance.
  • the Layered-Spinel structure lithium-rich solid solution also has disadvantages: Although the material of the Spinel structure is superior to the Layered structure, the discharge capacity of the material of the Spinel structure is low, and therefore, it is known from the above that the existing lithium is rich. Solid solution materials have poor stability under high voltage conditions, low discharge capacity, poor cycle performance, etc., and are difficult to commercialize. Technical Problem Lithium-rich cathode material with high discharge capacity and good cycle performance.
  • Another object of an embodiment of the present invention is to provide a lithium battery positive electrode containing the lithium-rich positive electrode material.
  • a lithium-rich cathode material which is a cladding structure
  • x and z are molar ratios, 0 ⁇ 1, 0 ⁇ 1, 0 ⁇ d ⁇ l/3; ⁇ is at least one of ⁇ , Ti, Zr, Cr, and Me is at least one of Mn, Co, Ni, Ti, Cr, V, Fe, Ah Mg, Zr, My Is at least one of Mn, Ni, Co;
  • the coating layer of the coating structure is a compound of the formula M m M z , wherein M m is at least one of Zn, Ti, Zr, and A1, and M z is 0 or F.
  • the ratio of the radius of the core body to the thickness of the cladding layer is (25 to 100): 1.
  • Li 1+d My 2 — d O in the structural formula of the above-mentioned core body has a spinel structure.
  • xLi 2 M0 3 ⁇ (lx)LiM e0 2 in the structural formula of the above-mentioned core body has a layered structure.
  • the lithium-rich positive electrode material has a particle diameter of 5 ⁇ m to 10 ⁇ m.
  • a lithium-rich positive electrode material precursor having a structural formula of z[xLi 2 M0 3 .(lx)LiMe0 2 ].(lz)Li 1+d My 2 _ d O, wherein x and z are molar ratios, 0 ⁇ 1, 0 ⁇ 1, 0 ⁇ d ⁇ l/3; M is Mn, Ti,
  • At least one of Zr and Cr, Me is at least one of Mn, Co, Ni, Ti, Cr, V, Fe, Al, Mg, and Zr, and My is at least one of Mn, Ni, and Co;
  • the first dry mixture or the second dry mixture is calcined at 250 to 550 ° C for 0.5 to 12 hours to obtain the lithium-rich positive electrode material.
  • the M m salt is at least one of a nitrate, a sulfate, an acetate, and a chloride.
  • the above hydroxide compound is at least one of NH 4 OH, NaOH, and LiOH.
  • the lithium-rich positive electrode material precursor is dispersed in a mixed solution containing a salt-containing positive electrode material precursor
  • the molar ratio of the body to the M m salt is (25 ⁇ 100): 1.
  • the pH of the solution containing the salt solution is adjusted to 9 to 12 after the addition of the hydroxide solution.
  • the salt is a nitrate of the compound, and the hydroxide is NH 4 OH.
  • the pH of the solution containing the salt and the fluoride is 5 to 9.
  • the salt is a nitrate of The fluoride is NH 4 F.
  • the method for obtaining the lithium-rich positive electrode material precursor is:
  • Soluble M salt, soluble Me salt and soluble My is weighed according to the molar ratio of the corresponding elements in the structural formula z[xLi 2 M0 3 .(lx)LiMe0 2 ].(lz)Li 1+d My 2 _ d O Salt and lithium compound;
  • the mixed solution is added dropwise to the hydrate solution to stir the reaction, and the resulting precipitate is sequentially subjected to solid-liquid separation, washed, and dried to obtain a dried precipitate;
  • the M salt is at least one of an acetate, a nitrate, a sulfate, and a chloride of M.
  • the above Me salt is at least one of acetate, nitrate, acid salt, and chloride of Me.
  • the above My salt is at least one of acetate, nitrate, acid salt, and chloride of My.
  • the lithium compound is at least one of lithium hydroxide and a lithium salt.
  • the sintering treatment has a temperature of 500 to 1000 ° C and a sintering time of 4 to 12 h.
  • a lithium battery positive electrode comprising a current collector and a positive electrode material bonded to the current collector, wherein the positive electrode material is the lithium-rich positive electrode material described above.
  • the lithium-rich cathode material is a coating structure, and the coating layer in the coating structure can effectively inhibit the lithium-rich phase and the spinel phase in the core body from contacting the electrolyte, and reduce the sensitization reaction on the surface of the lithium-rich cathode material.
  • the effect of HF on the lithium-rich phase and the spinel phase is effectively reduced, thereby suppressing the precipitation of Me in the lithium-rich phase, slowing down the voltage platform during the cycle, and improving the cycle performance of the material.
  • the The conductivity of the cladding layer of the lithium-rich cathode material is superior to that of the core body, and the rate performance of the lithium-rich cathode material is effectively improved.
  • the coating structure is adopted to make the structure of the lithium-rich cathode material stable, and the electrical connection between the coating layer and the core body is maintained, thereby making the electron conduction stable and improving the electrochemical performance of the lithium-rich cathode material.
  • the various process technologies are mature, the conditions are easy to control, the production efficiency is high, and the production cost is lowered.
  • the positive electrode of the lithium battery of the above embodiment has the above-mentioned lithium-rich positive electrode material, and the lithium-rich positive electrode material has excellent performance as described above, so that the positive electrode of the lithium battery has high capacity, stable performance and long cycle life during operation.
  • the lithium battery of the above embodiment contains the positive electrode of the above lithium battery, the lithium battery has excellent cycle life and rate performance, and effectively solves the problem of voltage platform drop. It is because of the excellent performance of the lithium battery, thereby expanding the application range of the lithium battery.
  • FIG. 1 is a schematic structural view of a lithium-rich positive electrode material according to an embodiment of the present invention
  • FIG. 2 is a flow chart of a preparation method of a lithium-rich cathode material according to an embodiment of the present invention
  • FIG. 3 is a flow chart of another preparation method of a lithium-rich cathode material according to an embodiment of the present invention.
  • FIG. 4 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. 5 is a flow chart of a method for preparing a lithium battery according to an embodiment of the present invention. Embodiments of the invention
  • the present invention provides a lithium-rich positive electrode material having stable structure, high discharge capacity and good cycle performance.
  • the lithium-rich cathode material is a cladding structure comprising a core body 1 and a cladding layer 2, the microstructure of which is shown in FIG. Among them, the structural formula of core 1 is as follows:
  • x and z are molar ratios, 0 ⁇ ⁇ ⁇ 1, 0 ⁇ ⁇ ⁇ 1, 0 ⁇ d ⁇ l/3; M is at least one of Mn, Ti, Zr, Cr, and Me is at least one of Mn, Co, Ni, Ti, Cr, V, Fe, Ah Mg, Zr, My It is at least one of Mn, Ni, and Co.
  • xLi 2 M0 3 .(lx)LiMe0 2 in the structural formula of the core body 1 has a layered structure
  • Li 3 _ 2y M, 2y P0 4 is in the lattice of xLi 2 M0 3 .(lx)LiMe0 2 It has a spinel structure distribution
  • the coating layer 2 is a compound of the formula M m M ⁇ ⁇ , wherein M m is at least one of Zn, Ti, Zr, and A1, and M z is 0 or F.
  • the inventors have found that the ratio between the radius of the core body 1 of the lithium-rich cathode material and the thickness of the cladding layer 2 in the above embodiment can be appropriately adjusted, and the lithium-rich phase and the spinel in the core 1 can be better suppressed.
  • the contact of the stone phase with the electrolyte reduces the sensitization reaction on the surface of the lithium-rich positive electrode material, effectively reduces the effect of HF on the lithium-rich phase and the spinel phase, thereby suppressing the precipitation of Me in the lithium-rich phase and slowing down the cycle.
  • the drop of the voltage platform during the process improves the cycle performance of the material. Therefore, in a preferred embodiment, the ratio between the radius of the core body 1 of the lithium-rich positive electrode material and the thickness of the cladding layer 2 is (25 to 100): 1.
  • the inventors have further found that controlling the particle size of the lithium-rich positive electrode material in the above embodiment can effectively improve the discharge capacity, rate performance, first charge and discharge efficiency, and cycle life of the lithium-rich positive electrode material. Therefore, in a preferred embodiment, the lithium-rich positive electrode material has a particle size of 5 ⁇ m to 10 ⁇ m.
  • the coating layer 2 in the lithium-rich cathode material coating structure in the above embodiment can effectively inhibit the lithium-rich phase and the spinel phase in the core body 1 from contacting the electrolyte, and reduce the sensitization reaction on the surface of the lithium-rich cathode material.
  • the effect of HF on the lithium-rich phase and the spinel phase is effectively reduced, thereby suppressing the precipitation of Me in the lithium-rich phase, slowing down the voltage platform during the cycle, and improving the cycle performance of the material.
  • the coating layer 2 of the lithium-rich cathode material has better conductivity than the core 1 and effectively improves the rate performance of the lithium-rich cathode material.
  • the coating structure is adopted to make the structure of the lithium-rich cathode material stable, and the coating 2 and the core body 1 maintain a stable electrical connection, thereby making the electron conduction stable and improving the electrochemical performance of the lithium-rich cathode material.
  • the lithium-rich phase and the spinel phase in the nucleation body of the lithium-rich cathode material can be further inhibited from contacting with the electrolyte, and the lithium-rich cathode material is lowered.
  • Surface sensitization reaction By adjusting the type and content of each element in the core body 1, the first charge and discharge efficiency and cycle life of the lithium-rich cathode material can be further improved.
  • the embodiment of the present invention further provides a preparation method of the lithium-rich cathode material.
  • the process flow of the method for preparing the lithium-rich cathode material is shown in FIG. 2, and specifically includes the following steps:
  • Step S01. Obtain a lithium-rich positive electrode material precursor:
  • a lithium-rich positive electrode material precursor having a structural formula of z[xLi 2 M0 3 .(lx)LiMe0 2 ].(lz)Li 1+d My 2 _ d O, wherein x and z are molar ratios, 0 ⁇ 1, 0 ⁇ 1, 0 ⁇ d ⁇ l/3; M is at least one of Mn, Ti, Zr, Cr, and Me is Mn, Co, Ni, Ti, Cr, V, Fe And at least one of Al, Mg, and Zr, and My is at least one of Mn, Ni, and Co;
  • Step S02. Preparing the first dry mixture:
  • the first dry mixture prepared in the step S02 is calcined at 250 to 550 ° C for 0.5 to 12 hours to obtain the lithium-rich positive electrode material.
  • the lithium-rich positive electrode material precursor having the structural formula of the above step S01 is z[xLi 2 M0 3 .(lx) LiMe0 2 ]. (lz) Li 1+d My 2 _ d O is commercially available.
  • the preparation can also be prepared according to the following method, and the preparation method comprises the following steps:
  • Step SOIL Weighs the soluble M salt, the soluble Me salt, and the molar ratio of the corresponding element in the structural formula z[xLi 2 M0 3 .(lx)LiMe0 2 ].(lz)Li 1+d My 2 _ d O Soluble My salt and lithium compound;
  • Step SO 12 Dissolve the M salt, the Me salt and the My salt in the step S011 to prepare a mixed solution; Step S013.
  • the mixed solution in the step S012 is added dropwise to the hydrate solution to stir the reaction, and the resulting precipitate is sequentially Performing solid-liquid separation, washing, and drying to obtain a dried precipitate;
  • Step S014 Mixing the precipitate in step S013 with the lithium compound and sintering, thereby obtaining To a lithium-rich positive electrode material precursor having the general formula z[xLi 2 M0 3 .(lx)LiMe0 2 ].(lz)Li 1+d My 2 _ d O .
  • the M salt in the above step S011 is preferably at least one selected from the group consisting of acetate, nitrate, sulfate, and chloride of M; and the Me salt is preferably selected from the group consisting of acetate, nitrate, and acid salt of Me.
  • the My salt is preferably at least one selected from the group consisting of acetate, nitrate, sulfate, and chloride of My;
  • the lithium compound is preferably at least one selected from the group consisting of lithium hydroxide and lithium salt.
  • the lithium salt may be a lithium salt commonly used in the art.
  • the molar ratio of the above M salt, Me salt and My salt is 1: (0.1 ⁇ 0.4) : (0.01 - 0.1); in order to ensure the content of lithium element in the precursor of the lithium-rich positive electrode material, the final of the lithium compound The amount is more than 3 to 8% (mass ratio) based on the amount of the formula.
  • the solvent used for dissolving the M salt, the Me salt and the My salt is preferably water, more preferably distilled water.
  • the solvent may also be selected from other solvents known in the art which are capable of dissolving the M salt, the Me salt and the My salt.
  • the concentration of the M salt, Me salt or My salt in the mixed solution prepared is preferably from 0.1 mol/L to 10 mol/L.
  • the concentration of the mixed solution is not particularly limited.
  • the ⁇ 1, Me, and My ions are combined with Off to form a precipitate.
  • the amount of the hydroxide should be sufficient, that is, to ensure the complete precipitation of M, Me, My ions.
  • the hydroxide may be a soluble hydroxide commonly used in the art, preferably potassium hydroxide, in a solution concentration of from 1 to 4 mol/L.
  • the solid-liquid separation and washing in the step S013 may be carried out by a method generally used in the art, and in the examples of the present invention, there are no particular limitations or requirements. Drying is preferably carried out by drying the washed precipitate at 100 ° C for 8 to 24 hours to remove the reaction solvent and the washing liquid.
  • the precipitate before the precipitate is mixed with the lithium compound, the precipitate is preferably pulverized, uniformly mixed with the lithium compound, and the mixture is pressed into pellets according to a general method in the art, and then the pellet is subjected to sintering treatment.
  • the sintering temperature is preferably 500 to 1000 ° C, and the sintering time is preferably 4 to 12 h.
  • the M m salt is preferably at least one selected from the group consisting of nitrates, sulfates, acetates, and chlorides of M m .
  • Hydroxide It is preferably selected from at least one selected from the group consisting of NH 4 OH, NaOH, and LiOH.
  • the salt is ⁇ . ⁇ , The hydroxide is NH 4 0H, and the pH of the reaction system containing the salt solution is adjusted to 9.0 ⁇ 12.0 by controlling the amount of NH 4 OH added.
  • the lithium-rich positive electrode material precursor is dispersed in the solution in which the lithium salt is dissolved.
  • the lithium-rich positive electrode material precursor is first pulverized and then dispersed into the solution by ultrasonic dispersion. It is of course also possible to carry out the dispersion by other means known in the art, which, regardless of the manner in which it is dispersed, should uniformly disperse the lithium-rich positive electrode material precursor in the solution in which the salt is dissolved.
  • the solvent used for dissolving the salt may be selected from water, and it is of course also possible to use other solvents which are soluble in the art.
  • the molar ratio of the lithium-rich positive electrode material precursor to the M m salt is preferably (25 to 100): 1.
  • the preferred amount ratio can effectively control the content of both the cladding layer and the core body of the lithium-rich cathode material, thereby achieving excellent performance of the lithium-rich cathode material.
  • the solid-liquid separation and washing in the step S02 may be carried out by a method generally used in the art, and in the embodiment of the invention, there is no particular limitation or requirement. Drying is preferably carried out by drying the washed precipitate at 100 ° C for 8 to 24 hours to remove the reaction solvent and the washing liquid.
  • step S03 in the calcination condition, the precipitate adsorbed on the surface of the lithium-rich positive electrode material precursor is melted and decomposed to form a coating layer of M m O, thereby forming a lithium-rich positive electrode material having a structure as shown in FIG.
  • the embodiment of the present invention further provides another preparation method of the lithium-rich cathode material.
  • the process flow of the method for preparing the lithium-rich cathode material is shown in FIG. 3, and specifically includes the following steps:
  • Step S04 Obtaining a lithium-rich positive electrode material precursor: Step S01 of the first preparation method like the above lithium-rich positive electrode material;
  • Step S05 Preparing a second dry mixture:
  • Step S6 Calcination treatment of the second dry mixture:
  • the second dry mixture prepared in step S05 is calcined at 250 ⁇ 550 ° C for 1 ⁇ 12 hours. To the lithium-rich positive electrode material.
  • the lithium-rich positive electrode material precursor having the structural formula of z[xLi 2 M0 3 .(lx) LiMe0 2 ]. (lz) Li 1+d My 2 _ d O in the above step S04 is commercially available.
  • the preferred acquisition method refer to steps S011 to S014 described above, and details are not described herein.
  • a nitrate, a sulfate, an acetate, and a chloride of M m is preferably selected.
  • the fluoride is preferably selected from the group consisting of NH 4 F.
  • the M m salt is ⁇
  • the fluoride is NH 4 F
  • the solution containing the ⁇ / ⁇ salt solution The pH of the reaction system was adjusted to 5.0 to 9.0.
  • the lithium-rich positive electrode material precursor is dispersed in the solution containing the salt and the fluoride.
  • the lithium-rich positive electrode material precursor is first pulverized and then dispersed into the solution by ultrasonic dispersion. It is of course also possible to carry out the dispersion by other means known in the art. Regardless of which method is used, the uniformity of the lithium-rich positive electrode material precursor should be uniformly dispersed in the solution in which the salt is dissolved.
  • the molar ratio of the lithium-rich positive electrode material precursor to the salt is preferably (25 to 100): 1. The preferred ratio can effectively control the content of both the cladding layer and the core of the lithium-rich cathode material, thereby achieving excellent performance of the lithium-rich cathode material.
  • step S06 under the calcination conditions, the M m salt and the fluoride are rearranged to form a coating layer of M m F, thereby forming a lithium-rich cathode material having a structure as shown in FIG. 1 .
  • the preparation method of the above-mentioned lithium-rich positive electrode material is simple, the process technology is mature, the conditions are easy to control, the production efficiency is high, and the production cost is lowered.
  • the present invention further provides a lithium battery positive electrode comprising a current collector and a positive electrode material bonded to the current collector, the positive electrode material being the lithium-rich positive electrode material described above, in order to save space, no longer Narration.
  • the current collector may use a current collector commonly used in the art, such as copper foil.
  • the lithium battery positive electrode has the lithium-rich positive electrode material described above, and since the lithium-rich positive electrode material has the excellent performance as described above, the lithium battery positive electrode has stable performance during operation, high capacity, and circulation. long life.
  • the embodiment of the invention further provides the above method for preparing a positive electrode of a lithium battery.
  • the lithium battery Please refer to FIG. 4 for the process of preparing the positive electrode pool, which includes the following steps:
  • Step S07 Preparing a positive electrode slurry: mixing the lithium-rich positive electrode material described above with an electrode conductive agent, a binder, and a solvent to prepare a positive electrode slurry;
  • Step S08 Applying the positive electrode slurry prepared in step S07 to the current collector;
  • Step S09 Drying, rolling and cutting treatment of the current collector:
  • the current collector coated with the positive electrode slurry treated in the step S08 is subjected to drying treatment, rolling, and cutting to obtain a positive electrode of the lithium battery.
  • the weight ratio of the lithium-rich cathode material, the electrode conductive agent, the binder, and the solvent in the above step S07 is preferably (8 to 9.5): (0.2 to 1.5): (0.3 to 1): 100, more preferably 8:1:1: 100.
  • the electrode conductive agent is graphite; the binder is sodium carboxymethyl cellulose (CMC); and the solvent is preferably water.
  • the electrode conductive agent, the binder, and the solvent may also be selected from other materials commonly used in the art.
  • the method of applying the positive electrode slurry in the above step S08 and the step S09 can be carried out by a method commonly used in the art for drying, rolling and cutting the current collector.
  • the method for preparing the positive electrode of the lithium battery only needs to apply the positive electrode slurry containing the lithium-rich positive electrode material described above on the current collector, and then dry, roll and cut, and the method is simple, and the condition is 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 a chemically reactive lithium battery such as a lithium ion battery or a lithium polymer battery.
  • the lithium battery contains the positive electrode of the lithium battery as described above, the lithium battery has stable electrochemical performance during charge and discharge cycles, high capacity, and long life.
  • the embodiment of the invention further provides a method for preparing the above lithium battery.
  • the process flow of the lithium battery preparation method is shown in Figure 3, which includes the following steps:
  • Step S10 Preparing a positive electrode and a negative electrode of a 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 S11 Preparing a battery cell: the positive electrode and the negative electrode of the battery prepared in step S10 are sequentially stacked in a negative stacking manner of the positive electrode/separator/lithium battery of the lithium battery, and wound up to form a battery cell; Step S12. Encapsulating the battery: The battery cell is placed in a battery case, and then the electrolyte is injected and sealed to obtain a lithium battery.
  • the preparation of the positive electrode in the above step S10, the preparation of the battery cell in the step S11, and the method of packaging the battery in the step S12 can be carried out according to a conventional method in the art.
  • the battery cells in step S11 may be square or other shapes according to different lithium batteries.
  • the preparation method of the lithium battery is mature in technology, easy to control, and high in pass rate.
  • the embodiment of the invention further provides the application range of the above lithium battery, and the application range includes a mobile terminal product, an electric vehicle, a power grid, a communication device, a power tool and the like.
  • the lithium battery is a lithium ion battery
  • the lithium ion battery is used in a communication device.
  • 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 ion battery described above, and the lithium ion battery may be one or more.
  • the power supply module includes more than two lithium ion batteries, the lithium ion batteries can be connected in parallel or in series or in series according to the power required by the working module.
  • the working module operates using the electrical energy provided by the power supply module.
  • the lithium battery has an excellent energy density, discharge capacity, cycle life and rate performance, thereby effectively expanding the application range of the lithium ion battery.
  • the lithium ion battery When the lithium ion battery is applied in a mobile terminal product, an electric vehicle, a power grid, a communication device, a power tool, the lithium ion battery can effectively work as a working module in a mobile terminal product, an electric vehicle, a power grid, a communication device, and a power tool.
  • Provide stable and continuous power reduce the frequency of electrochemical power supply replacement, and improve the user's use of mobile terminal products, electric vehicles, power grids, communication equipment, and power tools.
  • Example 1 The above lithium-rich positive electrode material, a preparation method thereof, a lithium battery positive electrode, a preparation method thereof, a lithium battery, a preparation method thereof, and the like are exemplified by a plurality of embodiments.
  • Example 1 The above lithium-rich positive electrode material, a preparation method thereof, a lithium battery positive electrode, a preparation method thereof, a lithium battery, a preparation method thereof, and the like are exemplified by a plurality of embodiments.
  • a lithium-rich positive electrode material which is a coating structure, wherein the structure of the core body of the cladding structure is
  • the coating layer is a compound of the general formula ZnO.
  • the preparation method is as follows:
  • Step S11 The structural formula is 0.85 [0.9 Li 2 MnO 3 -0. lLiMncsNiLsOz] ⁇ 0.15 ⁇ 2 ⁇ 4
  • step SOU was slowly added dropwise to a potassium hydroxide solution having a concentration of 2 mol/L, and the reaction was stirred for 1 hour, and the resulting precipitate was sequentially filtered, washed with distilled water, and dried at 100 ° C for 12 hours to obtain a dried solution.
  • Precipitate
  • step S012 The precipitate in step S012 is mixed with lithium hydroxide at a molar ratio of 1:1.05, and pulverized and then sintered at 800 ° C for 6 hours to obtain a structural formula of 0.85 [0.9 Li 2 MnO 3 -0. a lithium-rich cathode material of lLiMn 0 .5Ni L 5O2] .0.15LiMn 2 O 4 ;
  • the lithium-rich positive electrode material precursor in step S11 is ground and ultrasonically dispersed in a solution of dissolved acetic acid for 2 hours, then an ammonium hydroxide solution is added and the pH is adjusted to 11.5, and stirred at 70 ° C.
  • the reaction was carried out for 2 hours, and then filtered successively, washed with distilled water, and dried at 100 ° C for 12 hours to obtain a dried product;
  • step S12 The dried product in step S12 is pulverized, pressed into small balls, placed in a muffle furnace and calcined at 400 ° C for 1 hour, and cooled to obtain a ZnO-coated structure of the formula O.SS O ⁇ LizMnO O.lLiMnasNi Cy .O.lSLiMnzC ⁇ coated lithium-rich cathode material.
  • Example 2
  • the coating layer is a compound of the formula A1F 3 .
  • the preparation method is as follows:
  • Step S21 Preparation of a lithium-rich positive electrode material precursor having a structural formula of 0.85 [0.8Li 2 MnO 3 *0.2LiCoO 2 ]*0.15LiMn L5 Ni 0 . 425 C00.075O4:
  • step SOU Dissolving manganese acetate, nickel acetate, cobalt acetate (2 mol/L) in a molar ratio of 1:0.285:0.806 in 50 ml of water to obtain a mixed solution; 5022.
  • the mixed solution in step SOU was slowly added dropwise to a potassium hydroxide solution having a concentration of 2 mol/L, and the reaction was stirred for 1 hour, and the resulting precipitate was filtered successively, washed with distilled water, and dried at 100 ° C for 12 hours to obtain a dry Precipitate;
  • step S012 The precipitate in step S012 is mixed with lithium hydroxide at a molar ratio of 1:1.05, and pulverized and then sintered at 800 ° C for 6 hours to obtain a structural formula of 0.85 [0.8Li 2 MnO 3 *0.2LiCoO. 2 ] • O.lSLiMn Nia ⁇ Coat ⁇ C ⁇ lithium-rich cathode material;
  • Step S22 Coating process of the lithium-rich solid solution positive electrode material precursor:
  • the lithium-rich positive electrode material precursor in step S11 is ground and ultrasonically dispersed in a solution of dissolved aluminum nitrate for 2 hours, then an ammonium fluoride solution is added and the pH is adjusted to 7, and stirred at 80 ° C. The reaction was carried out for 5 hours, and then filtered successively, washed with distilled water, and dried at 100 ° C for 12 hours to obtain a dried product;
  • the dried product in the step S22 is pulverized, pressed into a pellet, placed in a muffle furnace and calcined at 400 ° C for 5 hours, and cooled to obtain an A1F 3 coating structure of 0.85 [0.8Li 2 MnO 3 * 0.2 lithium rich cathode material structure coated LiCoO 2] • 0.15LiMn 1. 5 Nio.425Coo.o750 4 in.
  • Preparation of positive electrode of lithium battery According to the positive electrode material, electrode conductive graphite, adhesive CMC, solvent water, the ratio of 8:1:1:100 by weight, and then stirred in a vacuum high speed mixer for 4-8 hours to form a uniform The positive electrode slurry was coated on the copper foil, and the copper foil was vacuum dried at 120 ° C for 24 hours, rolled, and cut to obtain a positive electrode sheet having a diameter of 15 mm. .
  • Preparation of lithium battery negative electrode Lithium metal sheet with a diameter of 15 mm and a thickness of 0.3 mm.
  • the positive electrode sheet, the negative electrode sheet and the Celgard 2400 polypropylene porous film are sequentially laminated in the order of lamination of the positive electrode sheet/separator/negative electrode sheet, and then wound into a square battery core, the electrolyte is filled in the battery case, and sealed. Button lithium-ion battery.
  • the electrolyte is a mixed solution of 1 M lithium hexafluorophosphate (LiPF 6 ) + ethylene carbonate / dimethyl carbonate (EC / DMC: volume ratio 1:1).
  • a lithium ion battery containing a lithium-rich positive electrode material was prepared by using the lithium-rich positive electrode material prepared in the above Comparative Examples 1 and 2, and the battery number was set to 1.1 and 2.1.
  • the lithium-rich positive electrode material of Examples 1 and 2 was a positive electrode material for preparing a lithium ion battery containing a lithium-rich positive electrode material, and the battery number was set to 1.2 and 2.2.
  • the battery numbers 1.1 and 2.1 are the same except for the materials.
  • the battery numbers 1.2 and 2.2 are the same except for the materials.
  • the lithium ion batteries prepared in the above Example 2 and Comparative Examples were subjected to electrochemical performance tests.
  • the surface-coated modified Layered-Spinel structure of lithium-rich cathode material has higher discharge capacity (as shown in Tables 1 and 2), higher initial charge and discharge efficiency (as shown in Tables 1 and 2), and better Cyclic performance (as shown in Tables 1, 2), and better rate performance (as shown in Table 2).

Abstract

一种富锂正极材料、锂电池正极和锂电池。该富锂正极材料为包覆结构，其中，包覆结构的核体的结构通式如下：z[xLi2MO3'(1-x)LiMeO2]•(1-z)Li1+dMy2-dO；式中，0<x<1，0<z<1，0<d<1/3；M为Mn、Ti、Zr、Cr中的至少一种，Me为Mn、Co、Ni、Ti、Cr、V、Fe、Al、Mg、Zr中的至少一种，My为Mn、Ni、Co中的至少一种；包覆结构的包覆层为通式MmMz的化合物，式中，Mm为Zn、Ti、Zr、Al中的至少一种，Mz为O或F。锂电池正极、锂电池中均含有该富锂正极材料。

Description

富锂正极材料、 锂电池正极和锂电池
技术领域
本发明属于电池技术领域， 具体涉及一种富锂正极材料、 锂电池正极和锂 电池。
说 背景技术
在众多的储能技术中， 锂离子电池由于具有能量密度大、 循环寿命长、 重 量轻、 无污染等优点， 被认为是下一代高效便书携式化学电源。 目前已经广泛的 用于数码相机、 智能手机、 笔记本电脑等方面。 随着锂离子电池能量密度的进 一步提升， 其应用领域将逐步的应用于电动车 （电动自行车、 电动汽车、 混合 动力汽车） 、 电网及其他大规模的储能领域。
目前， 随着可移动电子设备对高容量、 长寿命电池需求的日益增长， 人们 对锂离子电池的性能提出了更高的要求。 锂离子电池容量偏低已成为制约电池 工业发展的一个瓶颈。 其中， 正极材料的发展已经成为制约锂离子电池能量密 度进一步提升的关键因素。 目前常用的正极材料： 钴酸锂（LCO ) 、 锰酸锂 ( LMO ) 、 磷酸铁锂 ( LFP ) 、 三元 （NCM )等， 但这些正极材料的比容量大 都<160 mAh/g。
为 了进一步提高正极材料的比容量， 近年来富锂锰基固溶体 ( xLi2MnO (l-x)LiM02 ( layered-layered结构， M=Ni、 Co、 Mn、 Ti、 Zr 中的 一种或几种）被提出， 由于其具有高的放电容量（放电容量 >250 mAh/g, 充电 电压 >4.6 V ) , 且成本 ^艮低， 成为下一代正极材料的发展方向。 但是， 该 Layered-Layered富锂固溶体也存在严重缺陷： 在充放电的过程中 （ >4.5 V ) , 表面会发生敏化反应， 具体反应如下： LiM02→ ΠΛ_χΜ02_δ + xLi+ + δ 1202 + xe ( l )
Li2Mn03→ Mn02 + 2Li+ + 1/ 202 + 2e (2) 该 Layered-Layered富锂固溶体材料表面发生如上反应后，对材料的电化学 性能有如下不利影响：
1 ) 02的产生会形成 Li20， 充电过程， Li20很难回去， 造成首次充放电效 率很低 ( -70% ) ；
2 )材料的循环性能也会随着结构的变化， 而受到抑制；
3 )表面的破坏， 对材料的倍率性能也产生不利影响。
与此同时， 正极的电势高于 4.5 V时， 在循环过程中， 该 Layered- Layered 富锂固溶体材料中的锰可能会析出， 造成材料容量的快速衰减。
综上所述，现有 Layered-layered结构的富锂固溶体虽具有高的理论比容量， 但是由于材料自身在高电压条件的不稳定性， 而造成容量的快速衰减。
面对 Layered-layered结构的富锂固溶体的缺陷， 研究人员对材料进行改性 处理， 欲弥补材料本身的缺陷。 具体的如下：
1. Layered-rocksalt结构富锂固溶体：
Argonne国家实验室合成了 Layered-rocksalt新结构： xLi2MnOr(l-x)MO， 其中， 0 χ 1 , 并将这种新结构用于锂离子电池的正极材料， 这种新结构的富 锂固溶体结构表现出优秀的首次充放电性能和循环性能。
但该 Layered-rocksalt结构富锂固溶体也存在缺点：将 Layered-rocksalt结构 富锂固溶体材料用于锂离子电池 （相比于传统的 Layered-Layered 固溶体 xLi2Mn03 (l-x)LiM02, 0 < x < 1 ) Li的含量减少 , 会降低材料的放电容量。
2. Layered-Spinel结构富锂固溶体：
A. Manthiram等人合成得到了新的富锂固溶体 Layered-Spinel结构： xLi[Lio.2Mno.6Nio.i7Coo.o3]02-(l-x)Li[Mn1.5Nio.452Coo.o75]04, 0 < χ < 1 , 并将这种新 结构用于锂离子电池的正极材料，利用 Spinel结构的稳定性，表现出优秀的首次 充放电效率和循环性能。 但该 Layered-Spinel结构富锂固溶体也存在缺点： 虽然 Spinel结构的材料的 稳定性要优于 Layered结构， 但 Spinel结构的材料的放电容量要低， 因此， 这种 由上述可知， 现有富锂固溶体材料均存在高电压条件下稳定性差， 放电容 量低， 循环性能差等不足， 难于实现商业化。 技术问题 放电容量高和循环性能好的富锂正极材料。
本发明实施例的另一目的在于提供一种含有该富锂正极材料的锂电池正 极。
本发明实施例的又一目的在于提供一种含有该锂电池正极的锂电池。 技术解决方案
为了实现上述发明目的， 本发明的技术方案如下：
一种富锂正极材料， 其为包覆结构，
其中， 所述包覆结构的核体的结构通式如下：
z[xLi2M03 · (l-x)LiMe02] · (l-z)Li1+dMy2—dO; 式中， x、 z为摩尔计量比， 0<χ<1 , 0<ζ<1 , 0<d<l/3; Μ为 Μη、 Ti、 Zr、 Cr中的至少一种， Me为 Mn、 Co、 Ni、 Ti、 Cr、 V、 Fe、 Ah Mg、 Zr中的至少一种， My为 Mn、 Ni、 Co中的至少 一种；
所述包覆结构的包覆层为通式 MmMz的化合物， 式中， Mm为 Zn、 Ti、 Zr、 A1中的至少一种， Mz为 0或F。
优选地， 上述核体的半径与包覆层厚度的比为（25~100)： 1。
优选地， 上述核体的结构通式中的 Li1+dMy2_dO呈尖晶石结构。
优选地， 上述核体的结构通式中的 xLi2M03 · (l-x)LiM e02呈层状结构。 优选地， 上述富锂正极材料的颗粒粒径为 5 μιη~10 μιη。
以及， 一种上述富锂正极材料的制备方法， 包括如下步骤：
获取结构通式为 z[xLi2M03.(l-x)LiMe02].(l-z)Li1+dMy2_dO的富锂正极材料 前驱体， 式中， x、 z为摩尔计量比， 0<χ<1 , 0<ζ<1 , 0<d<l/3; M为 Mn、 Ti、
Zr、 Cr中的至少一种， Me为 Mn、 Co、 Ni、 Ti、 Cr、 V、 Fe、 Al、 Mg、 Zr中 的至少一种， My为 Mn、 Ni、 Co中的至少一种；
将所述富锂正极材料前驱体分散在含有 Mm盐的溶液中， 再加入氢氧化合 物溶液并在 50 ~ 120 °C下搅拌反应， 然后进行固液分离， 洗涤， 干燥， 得到第 一干燥混合物； 其中， Mm为 Zn、 Ti、 Zr、 A1中的至少一种； 或
将所述富锂正极材料前驱体分散在含有 Mm盐和氟化物的溶液中， 再在
50 ~ 120°C下搅拌直至干燥， 得到第二干燥混合物； 其中， ^^为 ！!、 Ti、 Zr、
A1中的至少一种；
将所述第一干燥混合物或第二干燥混合物在 250 ~ 550°C中煅烧 0.5 ~ 12小 时， 得到所述富锂正极材料。
优选地， 上述 Mm盐为硝酸盐、 ^£酸盐、 醋酸盐、 氯化物中的至少一种。 优选地， 上述氢氧化合物为 NH4OH、 NaOH、 LiOH中的至少一种。
优选地， 在上述制备第一干燥混合物或 /和第二干燥混合物的步骤中， 所述 富锂正极材料前驱体分散于含有^^盐溶液所形成的混合液中，所述富锂正极材 料前驱体与 Mm盐的摩尔比为 (25~100)： 1。
优选地， 在上述制备第一干燥混合物的步骤中， 加入所述氢氧化合物溶液 后并将所述含有^/^盐溶液的 pH调至 9 ~ 12。
具体地， 在制备上述第一干燥混合物的步骤中， 所述 ^^盐为^^的硝酸盐， 所述氢氧化合物为 NH4OH。
优选地， 在制备上述第二干燥混合物的步骤中， 所述含有^^盐和氟化物的 溶液的 pH为 5 ~ 9。
具体地， 在制备上述第二干燥混合物的步骤中， 所述 ^^盐为^^的硝酸盐， 所述氟化物为 NH4F。
优选地， 上述富锂正极材料前驱体的获取方法为：
按所述结构通式 z[xLi2M03.(l-x)LiMe02].(l-z)Li1+dMy2_dO中相应元素摩尔 计量比称取可溶性 M盐、 可溶性 Me盐和可溶性 My盐以及锂化合物；
将所述 M盐、 Me盐和 My盐溶解， 配制成混合溶液；
将所述混合溶液滴加至氢氧化合物溶液中搅拌反应， 将生成的沉淀依次进 行固液分离， 洗涤， 干燥， 得到干燥的沉淀物；
将所述沉淀物与所述锂化合物混合并烧结处理， 得到结构通式为
z[xLi2M03.(l-x)LiMe02].(l-z)Li1+dMy2_dO的富锂正极材料前驱体。
进一步优选地， 上述 M盐为 M的醋酸盐、 硝酸盐、 ^£酸盐、 氯化物中的至 少一种。
进一步优选地， 上述 Me盐为 Me的醋酸盐、 硝酸盐、 ^£酸盐、 氯化物中的 至少一种。
进一步优选地， 上述 My盐为 My的醋酸盐、 硝酸盐、 ^£酸盐、 氯化物中的 至少一种。
进一步优选地， 上述锂化合物为氢氧化锂、 锂盐中的至少一种。
进一步优选地， 上述烧结处理的温度为 500 ~ 1000°C , 烧结时间为 4 ~ 12 h。 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， 其特征在于： 所述正极材料为上述的富锂正极材料。
以及， 一种锂电池， 所述锂电池包括上述的锂电池正极。 有益效果
上述实施例中富锂正极材料为包覆结构， 该包覆结构中的包覆层能够有效 抑制核体中富锂相和尖晶石相与电解液接触， 降低富锂正极材料表面的敏化反 应， 有效降低了 HF对富锂相和尖晶石相的作用， 从而抑制了富锂相中的 Me 的析出， 减緩了循环过程中电压平台的下降， 提升材料的循环性能。 另外， 该 富锂正极材料的包覆层的导电性优于核体的导电性， 有效提高了该富锂正极材 料的倍率性能。 其次， 采用包覆结构， 使得该富锂正极材料结构的稳定性， 包 覆层与核体之间保持稳定的电联接， 从而使得电子传导稳定， 提高富锂正极材 料的电化学性能。
上述实施例富锂正极材料的制备方法中各工艺技术成熟， 条件易控， 生产 效率高， 降低了生产成本。
上述实施例锂电池正极由于含有上述富锂正极材料， 又由于该富锂正极材 料具有如上所述的优异性能， 使得该锂电池正极在工作过程中容量高， 性能稳 定， 循环寿命长。
上述实施例锂电池由于含有上述锂电池正极， 因此， 该锂电池具有优异的 循环寿命和倍率性能， 有效解决了电压平台下降的问题。 正是由于该锂电池具 有该优异性能， 从而扩大了该锂电池的应用范围。 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为本发明实施例富锂正极材料结构示意图；
图 2为本发明实施例富锂正极材料的一种制备方法流程图；
图 3为本发明实施例富锂正极材料的另一种制备方法流程图；
图 4为本发明实施例锂电池正极的制备方法流程图；
图 5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。
本发明实例提供一种结构稳定、放电容量高和循环性能好的富锂正极材料。 该富锂正极材料为包覆结构， 包括核体 1和包覆层 2, 其微观结构如图 1所示。 其 中， 核体 1的结构通式如下：
z[xLi2M03 - (l-x)LiMe02] - (l-z)Li1+dMy2.dO; 式中， x、 z为摩尔计量比， 0<χ<1 , 0<ζ<1 , 0<d<l/3; M为 Mn、 Ti、 Zr、 Cr中的至少一种， Me为 Mn、 Co、 Ni、 Ti、 Cr、 V、 Fe、 Ah Mg、 Zr中的至少一种， My为 Mn、 Ni、 Co中的至少 一种。 其中， 该核体 1结构通式中的 xLi2M03.(l-x)LiMe02呈层状结构， Li3_2yM，2yP04则在 xLi2M03.(l-x)LiMe02的晶格中呈尖晶石结构分布。 包覆层 2为 通式 MmM^^t合物， 式中， Mm为 Zn、 Ti、 Zr、 A1中的至少一种， Mz为0或F。
进一步地， 发明人经研究发现， 适当调整上述实施例中富锂正极材料的核 体 1的半径与包覆层 2的厚度之间的比值， 能更好的抑制核体 1中富锂相和尖 晶石相与电解液接触， 降低富锂正极材料表面的敏化反应， 有效降低了 HF对 富锂相和尖晶石相的作用， 从而抑制了富锂相中的 Me的析出， 减緩了循环过 程中电压平台的下降， 提升材料的循环性能。 因此， 在优选实施例中， 该富锂 正极材料的核体 1的半径与包覆层 2的厚度之间比为（25~100)： 1。
发明人进一步地经研究发现， 控制上述实施例中富锂正极材料的粒径， 能 有效的提高该富锂正极材料的放电容量、 倍率性能、 首次充放电效率、 循环寿 命。 因此， 在优选实施例中， 该富锂正极材料的颗粒粒径为 5 μιη~10 μιη。
由上述可知，上述实施例中富锂正极材料包覆结构中的包覆层 2能够有效抑 制核体 1中富锂相和尖晶石相与电解液接触， 降低富锂正极材料表面的敏化反 应， 有效降低了 HF对富锂相和尖晶石相的作用， 从而抑制了富锂相中的 Me的 析出， 减緩了循环过程中电压平台的下降， 提升材料的循环性能。 该富锂正极 材料的包覆层 2的导电性优于核体 1的导电性， 有效提高了该富锂正极材料的倍 率性能。 其次， 采用包覆结构， 使得该富锂正极材料结构的稳定性， 包覆层 2 与核体 1之间保持稳定的电联接，从而使得电子传导稳定，提高富锂正极材料的 电化学性能。 另外， 通过调整核体 1与包覆层 2之间的含量关系能进一步效抑该 富锂正极材料的制核体中富锂相和尖晶石相与电解液接触， 降低富锂正极材料 表面的敏化反应。通过调整核体 1中各元素的种类和含量， 能进一步提高该富锂 正极材料的首次充放电效率和循环寿命。
相应地， 本发明实施例还提供上述富锂正极材料的一种制备方法， 该富锂 正极材料制备方法工艺流程请参见图 2, 具体的包括如下步骤：
步骤 S01. 获取富锂正极材料前驱体：
获取结构通式为 z[xLi2M03.(l-x)LiMe02].(l-z)Li1+dMy2_dO的富锂正极材料 前驱体， 式中， x、 z为摩尔计量比， 0<χ<1 , 0<ζ<1 , 0<d<l/3; M为 Mn、 Ti、 Zr、 Cr中的至少一种， Me为 Mn、 Co、 Ni、 Ti、 Cr、 V、 Fe、 Al、 Mg、 Zr中 的至少一种， My为 Mn、 Ni、 Co中的至少一种；
步骤 S02. 制备第一干燥混合物：
将步骤 S01 中制备的富锂正极材料前驱体分散在含有 Mm盐的溶液中， 再 加入氢氧化合物溶液并在 50 ~ 120 °C下搅拌反应， 然后进行固液分离， 洗涤， 干燥， 得到第一干燥混合物； 其中， ^^为 ！!、 Ti、 Zr、 A1中的至少一种； 步骤 S03. 第一干燥混合物的煅烧处理：
将步骤 S02中制备的第一干燥混合物在 250 ~ 550 °C中煅烧 0.5 ~ 12小时， 得到所述富锂正极材料。
具体地 ， 上述步骤 S01 中 的 结 构 通 式 为 z[xLi2M03.(l-x) LiMe02]. (l-z)Li1+dMy2_dO的富锂正极材料前驱体可以市购。 还可以按照下述方 法制备获取， 其制备方法包括如下步骤：
步骤 SOIL 按所述结构通式 z[xLi2M03.(l-x)LiMe02].(l-z)Li1+dMy2_dO中相 应元素摩尔计量比称取可溶性 M盐、 可溶性 Me盐和可溶性 My盐以及锂化合 物；
步骤 SO 12. 将步骤 S011中的 M盐、 Me盐和 My盐溶解，配制成混合溶液； 步骤 S013. 将步骤 S012中的混合溶液滴加至氢氧化合物溶液中搅拌反应， 将生成的沉淀依次进行固液分离， 洗涤， 干燥， 得到干燥的沉淀物；
步骤 S014. 将步骤 S013 中的沉淀物与所述锂化合物混合并烧结处理， 得 到结构通式为 z[xLi2M03.(l-x)LiMe02].(l-z)Li1+dMy2_dO的富锂正极材料前驱体。 其中， 上述步骤 S011中的 M盐优选选自 M的醋酸盐、 硝酸盐、 ^£酸盐、 氯化物中的至少一种； Me盐优选选自 Me的醋酸盐、 硝酸盐、 酸盐、 氯化物 中的至少一种； My盐优选选自 My的醋酸盐、 硝酸盐、硫酸盐、 氯化物中的至 少一种； 锂化合物优选选自氢氧化锂、 锂盐中的至少一种， 锂盐可以是本领域 常用的锂盐。 作为优选实施例， 上述 M盐、 Me盐和 My盐摩尔比为 1: (0.1 ~ 0.4) ： (0.01 - 0.1); 为了保证该富锂正极材料前驱体中锂元素的含量， 锂化合 物的最终用量在按照该结构通式称取量的基础上多称取 3 ~ 8% (质量比）。
上述步骤 S012中， 溶解 M盐、 Me盐和 My盐所用的溶剂优选为水， 更优 选为蒸馏水。 当然， 溶剂还可以选用能够溶解 M盐、 Me盐和 My盐的本领域 公知其他溶剂。 所配制的混合溶液中， 该 M盐、 Me盐或 My盐的浓度优选为 0.1 mol/L~10 mol/L。 当然在本实施例中， 该混合溶液的浓度没有特别的限制。
上述步骤 S013中， 将混合溶液緩慢滴加至氢氧化合物溶液后， 该^1、 Me、 My离子与 Off结合而生成沉淀。 其中， 氢氧化合物的用量应该足量， 即保证 M、 Me、 My离子全部沉淀。 该氢氧化合物可以是本领域常用的可溶性的氢氧化合 物， 优选为氢氧化钾， 其溶液浓度为 1 ~ 4mol/L。
该步骤 S013中固液分离、 洗涤采用本领域常用的方法即可， 在本发明实施 例中， 没有特别的限制与要求。干燥优选是将经洗涤后的沉淀在 100°C下进行烘 干 8 ~ 24小时， 以除去反应溶剂以及洗涤液。
上述步骤 S014中， 将该沉淀物与锂化合物混合之前， 优选将沉淀物进行粉 碎处理， 再与锂化合物均匀， 并按照本领域通用方法将混合物压成小球， 然后 将小球进行烧结处理。 其中， 该烧结处理的温度优选为 500 ~ 1000°C , 烧结时间 优选为 4 ~ 12 h。
具体地， 上述步骤 S02中， 当加入氢氧化合物后， 该。！！-与^^离子结合而 生成沉淀，并通过电荷的吸附，吸附在富锂正极材料前驱体颗粒表面。其中， Mm 盐优选选 Mm的硝酸盐、 硫酸盐、 醋酸盐、 氯化物中的至少一种。 氢氧化合物 优选选自为 NH4OH、 NaOH、 LiOH中的至少一种。为了最大限度的沉淀 Mm离子， 在一优选实施例中， 该^^盐为^^^。^, 氢氧化合物为 NH40H， 并通过控制 NH4OH的添加量， 将含有^^盐溶液的反应体系的 pH调至 9.0 ~ 12.0。
该步骤 S02中， 富锂正极材料前驱体分散在溶解有^^盐的溶液中的方式优 选先将富锂正极材料前驱体进行粉碎， 然后通过超声分散的方式分散至该溶液 中。 当然也可以采用本领域公知的其他方式进行分散， 不管采用哪种方式分散， 均匀应该使得富锂正极材料前驱体在溶解有^^盐的溶液中均匀分散。用于溶解 该^^盐的溶剂可以选择水， 当然还可选用能溶解 的本领域常用的其他溶 剂。 其中， 在分散有富锂正极材料前驱体的混合液中， 富锂正极材料前驱体与 Mm盐的摩尔比优选为（25~100)： 1。 该优选用量比例能有效控制上述富锂正极 材料的包覆层与核体两者含量， 从而实现该富锂正极材料优异性能。
该步骤 S02中固液分离、洗涤采用本领域常用的方法即可，在本发明实施例 中， 没有特别的限制与要求。干燥优选是将经洗涤后的沉淀在 100°C下进行烘干 8 ~ 24小时， 以除去反应溶剂以及洗涤液。
上述步骤 S03中，在该煅烧条件，吸附在富锂正极材料前驱体表面的沉淀物 熔融并分解， 生成 MmO的包覆层， 从而形成结构如图 1所示的富锂正极材料。
相应地， 本发明实施例进一步提供上述富锂正极材料的另一种制备方法， 该富锂正极材料制备方法工艺流程请参见图 3, 具体的包括如下步骤：
步骤 S04. 获取富锂正极材料前驱体： 如同上文富锂正极材料的第一种制 备方法的步骤 S01;
步骤 S05. 制备第二干燥混合物：
将步骤 S04中制备的富锂正极材料前驱体分散在含有^^盐和氟化物的溶液 中， 再在 50 ~ 120°C下搅拌直至干燥， 得到第二干燥混合物； 其中， ^^为 ！!、 Ti、 Zr、 A1中的至少一种；
步骤 S06. 第二干燥混合物的煅烧处理：
将步骤 S05中制备的第二干燥混合物在 250 ~ 550 °C中煅烧 1 ~ 12小时，得 到所述富锂正极材料。
具体地 ， 上述步骤 S04 中 的 结 构 通 式 为 z[xLi2M03.(l-x) LiMe02].(l-z)Li1+dMy2_dO的富锂正极材料前驱体可以市购。 其优选获取方法参 见上文所述的步骤 S011至 S014, 在此不在赘述。
上述步骤 S05中， 优选选 Mm的硝酸盐、 硫酸盐、 醋酸盐、 氯化物中 的至少一种。 氟化物优选选自 NH4F。 为了最大限度的沉淀^^离子， 在一优选 实施例中， 该 Mm盐为^^^ ， 氟化物为 NH4F， 并通过控制 NH4F的添加量， 将含有^/^盐溶液的反应体系的 pH调至 5.0 ~ 9.0。
该步骤 S05中， 富锂正极材料前驱体分散在含有^^盐和氟化物的溶液中的 方式优选先将富锂正极材料前驱体进行粉碎， 然后通过超声分散的方式分散至 该溶液中。 当然也可以采用本领域公知的其他方式进行分散， 不管采用哪种方 式分散， 均匀应该使得富锂正极材料前驱体在溶解有^^盐的溶液中均匀分散。 其中， 在分散有富锂正极材料前驱体的混合液中， 富锂正极材料前驱体与和^^ 盐的摩尔比优选为 (25~100)： 1。 该优选用量比例能有效控制上述富锂正极材料 的包覆层与核体两者含量， 从而实现该富锂正极材料优异性能。
上述步骤 S06中， 在该煅烧条件下， Mm盐和氟化物会发生分子重新排布， 生成 MmF的包覆层， 从而形成结构如图 1所示的富锂正极材料。
由上所述， 上述富锂正极材料的制备方法工艺筒单， 各工艺技术成熟， 条 件易控， 生产效率高， 降低了生产成本。
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， 该正极材料为上文所述的富锂正极材料， 为了节约篇幅， 在此不再赘述。 其中， 集流体可以选用本领域常用的集流体， 如铜箔等。 这样， 该锂电池正极由于含有上文所述的富锂正极材料， 又由于该富锂正极材料具有 如上所述的优异性能， 因此， 该锂电池正极在工作过程中性能稳定， 容量高， 循环寿命长。
相应地， 本发明实施例进一步的提供了上述锂电池正极制备方法。 该锂电 池正极制备方法工艺流程请参见图 4, 其包括如下步骤：
步骤 S07. 配制正极浆料：将上文所述的富锂正极材料与电极导电剂、粘接 剂、 溶剂混合并配制成正极浆料；
步骤 S08. 将步骤 S07配制的正极浆料涂覆在集流体上；
步骤 S09. 集流体的干燥、 辊压和裁剪处理： 将经步骤 S08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 S07中的富锂正极材料、 电极导电剂、 粘接剂和溶剂的 重量比优选为（8~9.5):(0.2~1.5):(0.3~1) : 100, 更优选为 8:1:1: 100。 上述电极导电 剂为石墨； 所述粘接剂为羧甲基纤维素钠（CMC ) ； 溶剂优选为水。 当然， 该 电极导电剂、 粘接剂、 溶剂还可以选用本领域常用的其他物质。
上述步骤 S08中涂覆正极浆料的方式和步骤 S09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富锂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， 该锂电池为锂离子电池、 锂聚合物电池等电化学反应的 化学锂电池。
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 环过程中电化学性能稳定， 容量高， 寿命长。
相应地， 本发明实施例进一步的提供了一种上述锂电池制备方法。 该锂电 池制备方法工艺流程请参见图 3 , 其包括如下步骤：
步骤 S10. 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 S11. 制备电池电芯： 将步骤 S10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 S12.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 S10中正极的制备、 步骤 S11中的电池电芯的制备和步 骤 S12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 S11 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。
本发明实施例进一步提供了上述锂电池的应用范围， 该应用范围包括移动 终端产品、 电动汽车、 电网、 通信设备、 电动工具等。 如当锂电池为锂离子电 池时， 该锂离子电池在通信设备中的应用。 具体地， 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离子 电池， 该锂离子电池可以是一个或两个以上。 当供电模块包括两个以上的锂离 子电池时， 该锂离子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。 这样， 正是由于该锂电 池具有优异的能量密度、 放电容量、 循环寿命和倍率性能， 从而有效扩大了其 锂离子电池的应用范围。 将该锂离子电池在移动终端产品、 电动汽车、 电网、 通信设备、 电动工具中的应用时， 该锂离子电池能有效为移动终端产品、 电动 汽车、 电网、 通信设备、 电动工具中的工作模块提供稳定且持续的电能， 降低 电化学电源的更换频率， 提高了移动终端产品、 电动汽车、 电网、 通信设备、 电动工具的用户使用筒便性。
以下通过多个实施例来举例说明上述富锂正极材料及其制备方法、 锂电池 正极及其制备方法和锂电池及其制备方法等方面。 实施例 1
一种富锂正极材料， 其为包覆结构， 其中， 包覆结构的核体的结构通式为
0.85[0.9 U2MnO3- AUMn0.5Ni1.5O2] .0.15LiMn2O4, 包覆层为通式 ZnO的化合物。 其制备方法如下：
步骤 S11. 结构通式为 0.85[0.9 Li2MnO3-0. lLiMncsNiLsOz] ·0.15ϋΜη2Ο4的 富锂正极材料前驱体的制备：
SOU. 将摩尔比为 1:0.035的醋酸锰、 醋酸镍 ( 2 mol/L )溶解在 50 ml的水 中， 得到混合溶液；
5012. 将步骤 SOU 中的混合溶液緩慢滴加至浓度为 2mol/L的氢氧化钾溶 液中搅拌反应 1 小时， 将生成的沉淀依次进行过滤， 蒸馏水洗涤， 100°C干燥 12小时， 得到干燥的沉淀物；
5013. 将步骤 S012中的沉淀物与氢氧化锂混合， 摩尔比为 1:1.05, 粉碎后在 800 °C 下 进 行 烧 结 处 理 6 小 时 ， 得 到 结 构 通 式 为 0.85[0.9 Li2MnO3-0. lLiMn0.5NiL5O2] .0.15LiMn2O4的富锂正极材料；
步骤 S12. 富锂固溶体正极材料前驱体的包覆过程：
将步骤 S11中的富锂正极材料前驱体经研磨后采用超声的方式分散在溶解 醋酸辞的溶液中搅拌 2小时，再加入氢氧化铵溶液并将 pH调节至 11.5, 并在 70°C 下搅拌反应 2小时， 然后依次进行过滤， 蒸馏水洗涤， 100°C干燥 12小时， 得到 干燥物；
步骤 S13. 将干燥物煅烧处理：
将步骤 S12中的干燥物粉碎，压成小球后放入到马弗炉中于 400°C煅烧处理 1 小 时 ， 冷 却 ， 得 到 ZnO 包 覆 结 构 通 式 为 O.SS O^LizMnO O.lLiMnasNi Cy.O.lSLiMnzC^的包覆结构的富锂正极材料。 实施例 2
一种富锂正极材料， 其为包覆结构， 其中， 包覆结构的核体的结构通式为 0.85 [0.8Li2MnO3«0.2LiCoO2] ·0.15LiMn1.5Nio.425Coo.o7504 , 包覆层为通式 A1F3 的化合物。 其制备方法如下：
步骤 S21. 结构通式为 0.85[0.8Li2MnO3*0.2LiCoO2]*0.15LiMnL5Ni0.425 C00.075O4的富锂正极材料前驱体的制备：
S021. 将摩尔比为 1:0.285:0.806的醋酸锰、 醋酸镍、 醋酸钴 ( 2 mol/L )溶 解在 50 ml的水中， 得到混合溶液； 5022. 将步骤 SOU 中的混合溶液緩慢滴加至浓度为 2mol/L的氢氧化钾溶 液中搅拌反应 1 小时， 将生成的沉淀依次进行过滤， 蒸馏水洗涤， 100°C干燥 12小时， 得到干燥的沉淀物；
5023. 将步骤 S012中的沉淀物与氢氧化锂混合， 摩尔比为 1:1.05, 粉碎后在 800 °C下进行烧结处理 6小时， 得到结构通式为 0.85[0.8Li2MnO3*0.2LiCoO2] •O.lSLiMn Nia^Coat^C^的富锂正极材料；
步骤 S22. 富锂固溶体正极材料前驱体的包覆过程：
将步骤 S11中的富锂正极材料前驱体经研磨后采用超声的方式分散在溶解 硝酸铝的溶液中搅拌 2小时， 再加入氟化铵溶液并将 pH调节至 7, 并在 80°C下搅 拌反应 5小时， 然后依次进行过滤， 蒸馏水洗涤， 100°C干燥 12小时， 得到干燥 物；
步骤 S23. 将干燥物煅烧处理：
将步骤 S22中的干燥物粉碎， 压成小球后放入到马弗炉中于 400°C煅烧处 理 5 小时， 冷却， 得到 A1F3 包覆结构通式为 0.85[0.8Li2MnO3*0.2LiCoO2] •0.15LiMn1.5Nio.425Coo.o7504的包覆结构的富锂正极材料。
对比实例 1
一种富锂正极材料， 其结构式为：
0.85 [0.9Li2MnO 0. lLiMn0.5NiL5O2 ] ·0.15LiMn204。
对比实例 2
一种富锂正极材料， 其结构式为：
0.85[0.8Li2Mn03«0.2LiCo02]«0.15LiMn1.5Nio.425Coo.o7504
含有富锂正极材料的锂离子电池及其制备方法：
锂电池正极的制备： 按正极材料、 电极导电剂石墨、 粘接剂 CMC、 溶剂水 按照重量比为 8:1:1:100的比例混合后， 在真空高速搅拌机中搅拌 4 ~ 8小时形成 均匀的正极浆料，将该正极浆料均勾地涂覆在铜箔上，将铜箔在 120°C下真空烘 干 24小时、 辊压、 裁切制得尺寸为直径为 15 mm的正极片。 锂电池负极的制备： 直径为 15 mm、 厚度为 0.3 mm的金属锂片。
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，将电解液注满电池壳体中， 密封， 制成扣式锂离子电池。 其中电解液为 1 M 六氟磷酸锂 ( LiPF6 ) +碳酸乙 烯酯 /碳酸二甲酯（EC/DMC: 体积比 1:1 ) 混合溶液。
按照该锂离子电池的制备方法， 以上述对比实例 1、 2中制备的富锂正极材 料制备含有富锂正极材料的锂离子电池， 电池编号设定为 1.1、 2.1。 实施例 1、 2 中的富锂正极材料为正极材料制备含有富锂正极材料的锂离子电池， 电池编号 设定为 1.2、 2.2。 其中， 电池编号 1.1与 2.1除了材料不同之外， 其他条件均相同， 同理电池编号 1.2与 2.2除了材料不同之外， 其他条件均相同。 锂离子电池性能测试：
将上述实施例 2和对比实例中制备的锂离子电池进行电化学性能测试。
充放电性能测试和循环性能测试方式如表 1、 2中备注所示。
充放电性能测试和循环性能以及首次放电容量测试的结果如下表 1-2 所 表 1
Figure imgf000018_0001
表 2
Figure imgf000019_0001
通过表 1、 表 2的实验数据比较， 可以得出以下结论：
表面包覆改性的 Layered-Spinel结构的富锂正极材料， 相比于未包覆改性 的 Layered-Spinel的富锂正极材料有如下优势：
表面包覆改性的 Layered-Spinel结构的富锂正极材料拥有更高的放电容量 (如表 1、 2所示）、 更高的首次充放电效率（如表 1、 2所示）、 更好的循环性 能（如表 1、 2所示）， 以及更优秀的倍率性能（如表 2所示）。
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. 一种富锂正极材料， 其为包覆结构，
其中， 所述包覆结构的核体的结构通式如下：
z[xLi2M03 · ( 1 -x)LiMe02] - ( 1 -z)Li1+dMy2.dO； 式中， x、 z为摩尔计量比， 0<χ<1 , 0<ζ<1 , 0<d<l/3; M为 Mn、 Ti、 Zr、 Cr中的至少一种， Me为 Mn、 Co、 Ni、 Ti、 Cr、 V、 Fe、 Ah Mg、 Zr中的至少一种， My为 Mn、 Ni、 Co中的至少 一种；
所述包覆结构的包覆层为通式^/^^^的化合物， 式中， ^^为 ！!、 Ti、 Zr、 A1中的至少一种， Mz为0或F。
2. 如权利要求 1所述的锂电池正极材料， 其特征在于： 所述核体的半径与 包覆层厚度的比为 (25~100)： 1。
3. 如权利要求 1或 2所述的锂电池正极材料， 其特征在于： 所述核体的结 构通式中的 Li1+dMy2_dO呈尖晶石结构。
4. 如权利要求 1或 2所述的锂电池正极材料， 其特征在于： 所述核体的结 构通式中的 xLi2M03 · (l-x)LiM e02呈层状结构。
5. 如权利要求 1或 2所述的富锂正极材料， 其特征在于： 所述富锂正极材 料的颗粒粒径为 5 μΐϊΐ~10μηΐο
6.—种富锂正极材料的制备方法， 包括如下步骤：
获取结构通式为 z[xLi2M03.(l-x)LiMe02].(l-z)Li1+dMy2_dO的富锂正极材料 前驱体， 式中， x、 z为摩尔计量比， 0<χ<1 , 0<ζ<1 , 0<d<l/3; M为 Mn、 Ti、 Zr、 Cr中的至少一种， Me为 Mn、 Co、 Ni、 Ti、 Cr、 V、 Fe、 Al、 Mg、 Zr中 的至少一种， My为 Mn、 Ni、 Co中的至少一种；
将所述富锂正极材料前驱体分散在含有 Mm盐的溶液中， 再加入氢氧化合 物溶液并在 50 ~ 120 °C下搅拌反应， 然后进行固液分离， 洗涤， 干燥， 得到第 一干燥混合物， 其中 ^^为 ！!、 Ti、 Zr、 A1中的至少一种； 将所述第一干燥混 合物在 250 ~ 550°C中煅烧 0.5 ~ 12小时， 得到所述富锂正极材料； 或
将所述富锂正极材料前驱体分散在含有 Mm盐和氟化物的溶液中， 再在 50 ~ 120°C下搅拌直至干燥， 得到第二干燥混合物， 其中 Zn、 Ti、 Zr、 A1中的至少一种； 将所述第二干燥混合物在 250 ~ 550°C中煅烧 0.5 ~ 12小时， 得到所述富锂正极材料。
7. 如权利要求 6所述的富锂正极材料的制备方法， 其特征在于： 所述^^ 盐为硝酸盐、 ^£酸盐、 醋酸盐、 氯化物中的至少一种。
8. 如权利要求 6所述的富锂正极材料的制备方法， 其特征在于： 所述氢氧 化合物为 NH4OH、 NaOH、 LiOH中的至少一种。
9. 如权利要求 6所述的富锂正极材料的制备方法， 其特征在于： 在制备第 一干燥混合物或 /和第二干燥混合物的步骤中，所述富锂正极材料前驱体分散于 含有 Mm盐溶液所形成的混合液中， 所述富锂正极材料前驱体与 的摩尔 比为 ( 25-100 ): 1。
10. 如权利要求 6所述的富锂正极材料的制备方法， 其特征在于： 在制备 第一干燥混合物的步骤中， 加入所述氢氧化合物溶液后并将所述含有 Mm盐溶 液的 pH调至 9 ~ 12。
11. 如权利要求 6 ~ 10任一项所述的富锂正极材料的制备方法， 其特征在 于： 在制备所述第一干燥混合物的步骤中， 所述 ^^盐为 Mm的硝酸盐， 所述 氢氧化合物为 NH4OH。
12. 如权利要求 6所述的富锂正极材料的制备方法， 其特征在于： 在制备 第二干燥混合物的步骤中， 所述含有 Mm盐和氟化物的溶液的 pH为 5 ~ 9。
13. 如权利要求 6 ~ 12任一项所述的富锂正极材料的制备方法， 其特征在 于： 在制备所述第二干燥混合物的步骤中， 所述 ^^盐为 Mm的硝酸盐， 所述 氟化物为 NH4F。
14. 如权利要求 6所述的富锂正极材料的制备方法， 其特征在于： 所述富 锂正极材料前驱体的获取方法为：
按所述结构通式 z[xLi2M03.(l-x)LiMe02].(l-z)Li1+dMy2_dO中相应元素摩尔 计量比称取可溶性 M盐、 可溶性 Me盐和可溶性 My盐以及锂化合物；
将所述 M盐、 Me盐和 My盐溶解， 配制成混合溶液；
将所述混合溶液滴加至氢氧化合物溶液中搅拌反应， 将生成的沉淀依次进 行固液分离， 洗涤， 干燥， 得到干燥的沉淀物；
将所述沉淀物与所述锂化合物混合并烧结处理， 得到结构通式为 z[xLi2M03.(l-x)LiMe02].(l-z)Li1+dMy2_dO的富锂正极材料前驱体。
15. 如权利要求 14所述的富锂正极材料的制备方法， 其特征在于： 所述 M 盐为 M的醋酸盐、 硝酸盐、 酸盐、 氯化物中的至少一种； 所述 Me盐为 Me的醋酸盐、 硝酸盐、 酸盐、 氯化物中的至少一种； 所述 My盐为 My的醋酸盐、 硝酸盐、 酸盐、 氯化物中的至少一种； 所述锂化合物为氢氧化锂、 锂盐中的至少一种。
16. 如权利要求 14所述的富锂正极材料的制备方法， 其特征在于： 所述烧 结处理的温度为 500 ~ 1000°C , 烧结时间为 4 ~ 12 h。
17. 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， 其特征在于： 所述正极材料为权利要求 1 ~ 5任一所述的富锂正极材料。
18. 一种锂电池， 其特征在于： 所述锂电池包括权利要求 20所述的锂电池 正极。
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