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WO2024113250A1 - 锂锰镍复合氧化物及其制备方法、极片、电池、用电装置 - Google Patents

锂锰镍复合氧化物及其制备方法、极片、电池、用电装置 Download PDF

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WO2024113250A1
WO2024113250A1 PCT/CN2022/135597 CN2022135597W WO2024113250A1 WO 2024113250 A1 WO2024113250 A1 WO 2024113250A1 CN 2022135597 W CN2022135597 W CN 2022135597W WO 2024113250 A1 WO2024113250 A1 WO 2024113250A1
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Prior art keywords
composite oxide
nickel composite
lithium manganese
manganese nickel
positive electrode
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PCT/CN2022/135597
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English (en)
French (fr)
Inventor
张振国
王嗣慧
林文忠
范敬鹏
姚志杰
柳娜
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Contemporary Amperex Technology Co Ltd
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Contemporary Amperex Technology Co Ltd
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Priority to PCT/CN2022/135597 priority Critical patent/WO2024113250A1/zh
Priority to CN202280094228.4A priority patent/CN119301772B/zh
Priority to EP22966992.4A priority patent/EP4579807A4/en
Priority to PCT/CN2022/138059 priority patent/WO2024113406A1/zh
Priority to CN202280094229.9A priority patent/CN119318030B/zh
Publication of WO2024113250A1 publication Critical patent/WO2024113250A1/zh
Priority to US18/961,478 priority patent/US20250091899A1/en
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G45/00—Compounds of manganese
    • C01G45/12—Complex oxides containing manganese and at least one other metal element
    • C01G45/1221—Manganates or manganites with trivalent manganese, tetravalent manganese or mixtures thereof
    • C01G45/1228—Manganates or manganites with trivalent manganese, tetravalent manganese or mixtures thereof of the type (MnO2)-, e.g. LiMnO2 or Li(MxMn1-x)O2
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/40—Complex oxides containing nickel and at least one other metal element
    • C01G53/42—Complex oxides containing nickel and at least one other metal element containing alkali metals, e.g. LiNiO2
    • C01G53/44—Complex oxides containing nickel and at least one other metal element containing alkali metals, e.g. LiNiO2 containing manganese
    • C01G53/50—Complex oxides containing nickel and at least one other metal element containing alkali metals, e.g. LiNiO2 containing manganese of the type (MnO2)n-, e.g. Li(NixMn1-x)O2 or Li(MyNixMn1-x-y)O2
    • 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
    • H01M4/13—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
    • H01M4/36—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
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/30—Three-dimensional structures
    • C01P2002/32—Three-dimensional structures spinel-type (AB2O4)
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
    • C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/12—Surface area
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/40—Electric properties
    • 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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • 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

Definitions

  • the present application relates to the field of new energy technology, and in particular to lithium manganese nickel composite oxide and its preparation method, positive electrode sheet, battery, and electrical device.
  • Lithium-ion batteries have the advantages of high voltage, light weight, long cycle life, no memory effect, good safety, etc., and can be widely used in digital products such as mobile phones, digital cameras, laptops, and power tools such as electric vehicles and hybrid electric vehicles.
  • Lithium-ion batteries include positive electrode materials, negative electrode materials, isolation membranes, electrolytes, and current collectors. Among them, the positive electrode material is the key to restricting the overall performance and cost of lithium-ion batteries.
  • Spinel-type lithium manganese nickel composite oxides can be used as positive electrode materials in batteries, but spinel-type lithium manganese nickel composite oxides have a high lithium deintercalation potential, which causes serious side reactions between the positive electrode material and the electrolyte.
  • the electrolyte is consumed to produce a large amount of gas, resulting in an increase in the risk of battery cell swelling and accelerated capacity decay.
  • the positive electrode material undergoes ion dissolution due to side reactions, among which Mn 2+ dissolves more, and the dissolved Mn 2+ will be deposited on the surface of the negative electrode, destroying the SEI film (Solid Electrolyte Interface), accelerating the capacity decay of the negative electrode and the battery.
  • the main technical problem solved by the present application is to provide a spinel lithium manganese nickel composite oxide and its preparation method, positive electrode plate, battery and power-consuming device, which can improve the stability of the positive electrode active material and thus increase the capacity of the battery.
  • the average chemical composition of the lithium manganese nickel composite oxide is Li 1+a M x Ni 0.5+z Mn 1.5-xz O 4-k , wherein 0 ⁇ a ⁇ 0.3, 0 ⁇ x ⁇ 0.2, -0.3 ⁇ z ⁇ 0.3, 0 ⁇ k ⁇ 0.2, and M includes one or more elements of Na, Si, P, S, Nb, Mo, Ru, Te, Ce, Ta, and W.
  • the average chemical composition of the lithium manganese nickel composite oxide is Li 1+a M x N y Ni 0.5+z Mn 1.5-xyz O 4-kq Q q , wherein 0 ⁇ a ⁇ 0.3, 0 ⁇ x ⁇ 0.2, 0 ⁇ y ⁇ 0.3, -0.3 ⁇ z ⁇ 0.3, 0 ⁇ k ⁇ 0.2, 0 ⁇ q ⁇ 0.5, M includes one or more elements selected from the group consisting of Na, Si, P, S, Nb, Mo, Ru, Te, Ce, Ta, and W, N includes one or more elements selected from the group consisting of Mg, Al, K, Sc, Ti, V, Cr, Fe, Co, Rb, Sr, Y, Zr, Rh, Sb, La, Sm, Gd, Yb, Lu, and Hf, and Q includes one or more elements selected from the group consisting of F, Cl, Br, and I.
  • the ratio of the battery's charging capacity in the range of 3.5-4.4V to the total charging capacity in the range of 3.5-4.95V is less than or equal to 15%.
  • 0 ⁇ x+y+z 0.3.
  • the lithium manganese nickel composite oxide includes one or more of single crystal particles, quasi-single crystal particles, and secondary particles.
  • the number of crystallites contained in a single secondary particle is 1 ⁇ n ⁇ 8.
  • the grain shape includes one or more of a spherical shape, an octahedron, a regular shape with sharp edges and cut corners of an octahedron, an octahedron with rounded corners, and/or a regular shape of a polyhedron with sharp edges and cut corners of an octahedron with rounded corners.
  • the volume median particle size of the lithium manganese nickel composite oxide is 2 ⁇ m ⁇ D V50 ⁇ 20 ⁇ m.
  • the powder pH of the lithium manganese nickel composite oxide is 10 ⁇ pH ⁇ 12.
  • the specific surface area of the lithium manganese nickel composite oxide is 0 ⁇ BET ⁇ 0.8 m 2 /g.
  • a positive electrode plate including a positive electrode material and a positive electrode current collector, and the positive electrode material includes any of the above lithium manganese nickel composite oxides.
  • a battery including: a positive electrode plate, a separator and a negative electrode plate, the separator is located between the positive electrode plate and the negative electrode plate to play an isolation role, and the positive electrode plate includes any of the above positive electrode plates.
  • the battery further comprises an electrolyte
  • the electrolyte solvent of the electrolyte comprises one or more of fluorocarbonates, fluorocarboxylates, sulfones, and fluoroethers.
  • another technical solution adopted in the present application is: to provide a method for preparing a lithium manganese nickel composite oxide, comprising: providing raw materials for the lithium manganese nickel composite oxide; heat-treating the raw materials for the lithium manganese nickel composite oxide in an oxygen-containing atmosphere to obtain any of the above lithium manganese nickel composite oxides.
  • heat treating the raw material of lithium manganese nickel composite oxide in an oxygen-containing atmosphere includes: heating the raw material of lithium manganese nickel composite oxide to T1, and keeping it warm for 2-50 hours to obtain a lithium manganese nickel composite oxide intermediate; wherein 850°C ⁇ T1 ⁇ 1100°C.
  • the preparation method of lithium manganese nickel composite oxide further includes: heating the lithium manganese nickel composite oxide intermediate to T2, keeping it warm for 0.5-20h, to obtain a lithium manganese nickel composite oxide preform; wherein T1-200°C ⁇ T2 ⁇ T1 and T2 ⁇ 800°C.
  • the preparation method of lithium manganese nickel composite oxide further includes: heating the lithium manganese nickel composite oxide preform to T3, and keeping the temperature for 5-30 hours to obtain the lithium manganese nickel composite oxide; wherein 500°C ⁇ T3 ⁇ 800°C.
  • providing a raw material for a lithium manganese nickel composite oxide comprises: providing a stoichiometric ratio of Li 2 CO 3 , Ni 0.5+z Mn 1.5-xz (OH) 4-2x , and M b O c powders according to a target composition Li 1+ a M x Ni 0.5+z Mn 1.5- xz O 4-k , and mixing them uniformly to obtain a raw material for a lithium manganese nickel composite oxide, wherein 0 ⁇ a ⁇ 0.3, 0 ⁇ x ⁇ 0.2, -0.3 ⁇ z ⁇ 0.3, 0 ⁇ k ⁇ 0.2, and M comprises one or more elements selected from sodium (Na), silicon (Si), phosphorus (P), sulfur (S), niobium (Nb), molybdenum (Mo), ruthenium (Ru), tellurium (Te), cerium (Ce), tantalum (Ta), and tungsten (W).
  • the beneficial effect of the present application is that, different from the prior art, the present application can improve the structural stability of the lithium manganese nickel composite oxide by regulating the characteristic peak intensity ratio I 111 /I 400 of the spinel lithium manganese nickel composite oxide within a preferred range, thereby reducing its activity in reacting with the electrolyte when used as a positive electrode material, thereby improving the overall performance of the battery.
  • FIG1 is an X-ray diffraction pattern of some embodiments and comparative examples of the present application.
  • FIG2 is an X-ray diffraction pattern of some embodiments and comparative examples of the present application.
  • FIG3 is a first cycle charging curve of button batteries of some embodiments and comparative examples of the present application.
  • FIG4 is a morphology diagram of the positive electrode active material of Example 3 of the present application tested by a scanning electron microscope;
  • FIG5 is a morphology diagram of the positive electrode active material of Example 36 of the present application tested by a scanning electron microscope;
  • FIG6 is a morphology image of the positive electrode active material of Example 46 of the present application tested by a scanning electron microscope;
  • FIG7 is a morphology diagram of the positive electrode active material of Example 47 of the present application tested by a scanning electron microscope;
  • FIG8 is a morphology diagram of the positive electrode active material of Comparative Example 1 of the present application tested using a scanning electron microscope.
  • the term "about” is used to describe and illustrate small changes.
  • the term may refer to an example in which the event or situation occurs precisely and an example in which the event or situation occurs very approximately.
  • the term may refer to a range of variation of less than or equal to ⁇ 10% of the numerical value, such as less than or equal to ⁇ 5%, less than or equal to ⁇ 4%, less than or equal to ⁇ 3%, less than or equal to ⁇ 2%, less than or equal to ⁇ 1%, less than or equal to ⁇ 0.5%, less than or equal to ⁇ 0.1%, or less than or equal to ⁇ 0.05%.
  • a list of items connected by the term "at least one of” can mean any combination of the listed items. For example, if items A and B are listed, the phrase "at least one of A and B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C.
  • Item A can include a single element or multiple elements.
  • Item B can include a single element or multiple elements.
  • Item C can include a single element or multiple elements.
  • Lithium-ion batteries include positive electrodes, negative electrodes, separators, electrolytes, etc.
  • the positive electrode includes a positive electrode current collector and a positive electrode material disposed on the positive electrode current collector.
  • the positive electrode material is the key to restricting the overall performance of lithium-ion batteries.
  • the positive electrode materials currently used are prone to serious side reactions with the electrolyte, which will increase the risk of cell swelling, accelerate the capacity decay of the negative electrode, and the capacity decay of the battery.
  • the current problems can usually be improved by surface coating the positive electrode material, structurally regulating the positive electrode material to reduce the oxygen defects of the material, increasing the particle size of the positive electrode material, reducing the specific surface area of the positive electrode material, surface modifying the positive electrode material to stabilize the material surface, and reducing the contact between the electrolyte and the positive electrode material.
  • these methods still have certain disadvantages.
  • the present application selects spinel lithium manganese nickel composite oxide as the positive electrode material, and regulates the crystal structure, element composition and content of the lithium manganese nickel composite oxide and the preparation process to improve the performance of the lithium manganese nickel composite oxide, improve the thermodynamic trend and growth power of the lithium manganese nickel composite oxide to grow towards a more stable structure, thereby improving the structural stability of the lithium manganese nickel composite oxide, and then can significantly improve the comprehensive performance of the lithium manganese nickel composite oxide used as a positive electrode material in the battery, specifically, can improve the battery capacity.
  • the lithium manganese nickel composite oxide refers to an oxide containing lithium manganese nickel, that is, in addition to lithium manganese nickel, other elements can be included in the oxide, so it is also called a lithium manganese nickel composite oxide.
  • the lithium manganese nickel composite oxide can be tested using a powder X-ray diffractometer with CuK ⁇ 1 rays according to the standard JIS K 0131-1996.
  • the end face here is the end face theoretically grown.
  • the structural stability of the lithium manganese nickel composite oxide can be improved, thereby reducing its activity in reacting with the electrolyte when used as a positive electrode material, and improving the overall performance of the battery.
  • the first preferred growth crystal plane of the spinel-type lithium-manganese-nickel composite oxide is the (111) plane, that is, the atoms spread and grow layer by layer along the (111) plane, so the stacking quality of the (111) plane determines the stability of the crystal structure.
  • a spinel-type lithium-manganese-nickel composite oxide grain can have multiple (111) faces (such as the eight side faces in the octahedral grain shape) growing simultaneously, and the crystal faces contact each other to form (a00) side faces. Therefore, the (111) face can be called the "basal face" of the spinel structure, and the (a00) face can be called the "end face" of the spinel structure.
  • E can indicate the degree of preference of the crystal plane (111); the larger the E value, the greater the degree of preference of the (111) plane, the lower the energy of the (111) plane, and thus the smoother the stacking of the (111) plane, the more stable the overall structure of the spinel-type lithium-manganese-nickel composite oxide, and thus the stability of the battery using the material is improved.
  • E can also be called the crystal plane preference index to characterize the stability of the crystal structure.
  • the (111) peak and the (400) peak are two of the three strong peaks with relatively large intensities.
  • I 111 /I 400 may be 2.2, 2.5, 2.6, 2.7, 2.9, etc.
  • the crystal growth direction and structural stability of the lithium manganese nickel composite oxide can be regulated by regulating the composition and content of the elements contained in the lithium manganese nickel composite oxide. That is, the E value can be regulated by regulating the composition and content of the elements contained in the lithium manganese nickel composite oxide.
  • the average chemical composition of the lithium manganese nickel composite oxide is Li 1+a M x Ni 0.5+z Mn 1.5-xz O 4-k , wherein 0 ⁇ a ⁇ 0.3, 0 ⁇ x ⁇ 0.2, -0.3 ⁇ z ⁇ 0.3, 0 ⁇ k ⁇ 0.2, and M includes one or more elements of sodium (Na), silicon (Si), phosphorus (P), sulfur (S), niobium (Nb), molybdenum (Mo), ruthenium (Ru), tellurium (Te), cerium (Ce), tantalum (Ta), and tungsten (W).
  • M includes one or more elements of sodium (Na), silicon (Si), phosphorus (P), sulfur (S), niobium (Nb), molybdenum (Mo), ruthenium (Ru), tellurium (Te), cerium (Ce), tantalum (Ta), and tungsten (W).
  • the Li content in the oxide is increased, that is, the ratio of the molar content of the elements at the Li position to the Ni/Mn position is greater than 0.5.
  • Increasing the Li content is conducive to the thermodynamic trend of the spinel-type lithium manganese nickel composite oxide to grow towards a stable structure.
  • the increase in Li content can promote the increase of the Mn valence state in the spinel structure, increase the Mn-O bond strength, and reduce the side reaction of the spinel-type lithium manganese nickel composite oxide with the electrolyte, that is, the increased Li can enter the Mn position in an appropriate amount to form Li doping, improve the structural stability of the material, and then reduce the side reaction with the electrolyte.
  • the thermodynamic trend of the spinel-type lithium manganese nickel composite oxide to grow towards a stable structure and the growth dynamics that is, the kinetic trend of growth).
  • an increase in Li content will reduce the degree of preference of the (111) face, that is, reduce the E value, and reduce the power of the spinel-type lithium manganese nickel composite oxide to grow into a stable structure.
  • increasing the Li content can improve the thermodynamic tendency of the spinel-type lithium-manganese-nickel composite oxide to grow toward a stable structure on the one hand, and reduce the driving force for the spinel-type lithium-manganese-nickel composite oxide to grow toward a stable structure on the other hand, that is, reduce the kinetic tendency.
  • the present application introduces the M element into the lithium manganese nickel composite oxide to modify the lithium manganese nickel composite oxide, so as to reconcile the contradiction between the thermodynamic trend and the growth power of the spinel-type lithium manganese nickel composite oxide to grow toward a stable structure, thereby achieving a significant improvement in the stability of the spinel-type lithium manganese nickel composite oxide structure.
  • the doping of the M element can increase the power of the spinel-type lithium manganese nickel composite oxide to grow toward a stable structure, so as to compensate for the weakening of the growth power caused by the increase in Li content.
  • M includes one or more elements of sodium (Na), silicon (Si), phosphorus (P), sulfur (S), niobium (Nb), molybdenum (Mo), ruthenium (Ru), tellurium (Te), cerium (Ce), tantalum (Ta), and tungsten (W).
  • M includes one or more elements of Si, P, Ru, Te, Ce, and Ta; further preferably, M includes one or more elements of P, Ru, Te, and Ta.
  • the M element may be distributed in the bulk phase of the spinel-type lithium-manganese-nickel composite oxide or on the surface of the material.
  • the selected M element can stabilize the crystal structure of the spinel lithium-manganese-nickel composite oxide on the one hand, and can also capture hydrogen fluoride (HF) in the electrolyte on the other hand.
  • HF hydrogen fluoride
  • the doping amount x of the M element needs to match the Li content a to better take into account the thermodynamic and kinetic trends of crystal growth, that is, to take into account the Li content and E value. To a certain extent, the more Li, the more element M needs to be doped to reconcile.
  • a/x can be 4, 6, 8, 11, 12, 15, 17, 19, etc.
  • a can be 0.04, 0.06, 0.08, 0.09, 0.11, 0.13, 0.14, etc.
  • x can be 0.005, 0.008, 0.02, 0.04, 0.05, 0.08, 0.09, etc.
  • the improvement effect can be optimized, and the battery capacity, kinetic performance and long-term performance of the battery using the material can be taken into account, such as extending the battery life.
  • the average chemical composition of the lithium manganese nickel composite oxide is Li 1+a M x N y Ni 0.5+z Mn 1.5-xyz O 4-kq Q q , wherein 0 ⁇ a ⁇ 0.3, 0 ⁇ x ⁇ 0.2, 0 ⁇ y ⁇ 0.3, -0.3 ⁇ z ⁇ 0.3, 0 ⁇ k ⁇ 0.2, 0 ⁇ q ⁇ 0.5, M includes one or more elements selected from Na, Si, P, S, Nb, Mo, Ru, Te, Ce, Ta, and W, N includes one or more elements selected from magnesium (Mg), aluminum (Al), potassium (K), scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), cobalt (Co), rubidium (Rb), strontium (Sr), yttrium (Y), zirconium (Zr), rhodium (Rh), antimony (Sb), lanthanum (La), samarium (Sm), gadolinium (Gd),
  • N element is an element that can enter Li position and/or Mn position and/or Ni position.
  • N includes one or more elements of K, Rb, Sr, Y, Rh, Sb, La, Sm, Gd, Yb, Lu, and Hf.
  • N element is doped into the spinel lithium-manganese-nickel composite oxide as other cations.
  • y can be 0.003, 0.008, 0.01, 0.07, 0.13, 0.19, 0.25, etc. The improvement effect is optimal when the doping amount of the N element is controlled within this range, and the battery capacity, kinetic performance, and long-term performance of the battery using the material can be taken into account.
  • z can be 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, etc. That is, the Ni content is also increased, and the increased Ni is beneficial to improving the average valence state of Mn and stabilizing the structure.
  • the increased Ni can also form a rock salt phase on the surface of the grains, protect the manganese-rich phase, and reduce the probability of Mn dissolution.
  • x+y+z can be 0.008, 0.03, 0.06, 0.09, 0.16, 0.21, 0.27, etc.
  • the total amount of cation doping is limited; by controlling the total amount of cation doping within this range, the capacity, kinetic performance and service life of the battery using the material can be taken into account.
  • 0 ⁇ q ⁇ 0.5 more preferably 0.001 ⁇ q ⁇ 0.2, more preferably 0.01 ⁇ q ⁇ 0.1.
  • q can be 0.006, 0.03, 0.07, 0.13, 0.18, 0.24, 0.33, 0.42, etc.
  • the doping amount of anions can be controlled, and the improvement effect is optimal when the anions are within this range.
  • 0 ⁇ k ⁇ 0.1 k may be 0.003, 0.005, 0.007, 0.009, etc.
  • I (21.5°-24°) /I 111 can be 0.3%, 0.8%, 1.2%, 1.7%, 2.6%, etc.
  • the peak position and peak intensity of the peak between 21.5°-24° can be regulated.
  • the inventors of the present application have found that the higher the peak intensity of the peak between 21.5°-24°, the more conducive it is to prolong the service life of the battery using the material, but after the peak intensity exceeds a certain value, the battery capacity drops sharply and the life deteriorates.
  • the ratio R of the battery's charging capacity in the 3.5-4.4V range to the total charging capacity in the 3.5-4.95V range is less than or equal to 15%; preferably, R is less than or equal to 10%; more preferably, 4% ⁇ R ⁇ 10%.
  • R can be 1%, 3%, 5%, 6%, 7%, 8%, 9%, 12%, 14%, etc.
  • the charge is charged at a small rate current constant current of 0.1C, and the ratio of the charging capacity in the 3.5-4.4V range to the total charging capacity in the 3.5-4.95V range is called the 4V platform ratio.
  • the larger the 4V platform ratio R the more Mn 3+ content it has, which also means that the average charge and discharge voltage is reduced.
  • the increase in the Mn 3+ content will increase the risk of Mn dissolution, and the reduction in the average discharge voltage means that the energy density is reduced. Therefore, it is necessary to adjust the R value not too large.
  • the inventors of the present application have found that when the E value of the spinel-type lithium-manganese-nickel composite oxide increases, it is often accompanied by an increase in R. In order to balance the two values, the comprehensive performance of the regulated battery is higher.
  • the inventors of the present application have further found that regulating the doping type and doping amount of the M element can balance the E value and the R value, and reasonably regulating the doping type and doping amount of the M element can increase the E value but not increase or even decrease the R value. Then a better material composition is obtained, and the specific component content is described above.
  • the lithium manganese nickel composite oxide includes one or more of single crystal particles, quasi-single crystal particles, and secondary particles.
  • the particles inside the single crystal are arranged regularly and periodically in three-dimensional space, or the whole crystal is composed of the same spatial lattice in the three-dimensional direction, and the arrangement of particles in the space of the whole crystal is long-range orderly.
  • Single crystal particles are also called primary particles, and primary particles can agglomerate to form secondary particles.
  • a secondary particle contains only a few or a dozen grains, it is called a quasi-single crystal particle.
  • the grain shape of the lithium manganese nickel composite oxide includes one or more of a spherical shape, an octahedron, a regular shape with sharp edges and edges of an octahedron, an octahedron with rounded edges and corners, and/or a regular shape of a polyhedron with sharp edges and edges of an octahedron with rounded edges and corners; preferably, the grain shape is an octahedron with rounded edges and corners and/or a regular shape of a polyhedron with sharp edges and edges of an octahedron with rounded edges and corners.
  • the surface of the octahedron and the polyhedron with sharp edges and cut corners is a crystal plane that is more conducive to Li + conduction, so the capacity and dynamic performance are better; the spherical grains can reduce the cracking and corrosion caused by stress concentration, so the subsequent processing performance of the material and the long-term service life of the battery using it are better.
  • the rounded octahedron and/or the polyhedron with sharp edges and cut corners take into account the advantages of the first two categories, taking into account the capacity, dynamic performance and long-term stability of the material.
  • the lithium manganese nickel composite oxide further includes secondary particles, and the number of crystal grains contained in a single secondary particle is 1 ⁇ n ⁇ 8, preferably 1 ⁇ n ⁇ 3.
  • n can be 2, 4, 5, 6, 7, etc.
  • the surface of the spinel-type lithium-manganese-nickel composite oxide particles is the area where side reactions are concentrated.
  • the grain surface of the spinel-type lithium-manganese-nickel composite oxide is the most stable crystal plane of Ni/Mn and Ni/Mn elements, and the M element dissolved in the spinel-type lithium-manganese-nickel composite oxide mainly enters the Ni/Mn position. Therefore, in the single crystal particles, the M element entering the crystal lattice is the most stable, and the surface coating containing the M element can also match well with the substrate surface, thereby bringing the modification effect of the M element to the best effect.
  • the surfaces of single crystal particles are relatively stable crystal planes, with a smaller specific surface area.
  • the probability of cracking and exposing unstable surfaces during processing and service is lower, which is beneficial to slowing down surface side reactions.
  • single crystals are more conducive to dynamic performance due to their small particles and are also not easy to crack.
  • the volume median particle size of the lithium manganese nickel composite oxide is 2 ⁇ m ⁇ D V50 ⁇ 20 ⁇ m; preferably, 3 ⁇ m ⁇ D V50 ⁇ 15 ⁇ m, and more preferably, 5 ⁇ m ⁇ D V50 ⁇ 10 ⁇ m.
  • D V50 may be 4 ⁇ m, 6 ⁇ m, 8 ⁇ m, 13 ⁇ m, 18 ⁇ m, etc.
  • the powder pH of the lithium manganese nickel composite oxide is 10 ⁇ pH ⁇ 12.
  • the spinel lithium manganese nickel composite oxide of the present application has stronger alkalinity, which can neutralize the strong acid generated under high voltage and reduce the surface damage of the positive electrode material; excessive alkalinity is not conducive to processing performance, and is easy to absorb moisture, react with the binder, and deteriorate battery performance.
  • the specific surface area of the lithium manganese nickel composite oxide is 0 ⁇ BET ⁇ 0.8m 2 /g; preferably, 0 ⁇ BET ⁇ 0.5m 2 /g, and more preferably, 0.1 ⁇ BET ⁇ 0.4m 2 /g.
  • it can be 0.2m 2 /g, 0.3m 2 /g, 0.6m 2 /g, 0.7m 2 /g, etc.
  • the specific surface area can be measured by gas adsorption method. A smaller specific surface area can slow down the surface side reaction. However, the specific surface area is greatly affected by the coating state. For example, the coating of nanoparticles can significantly increase the specific surface area, but the active specific surface area is actually reduced.
  • the crystal growth direction and structural stability of the lithium manganese nickel composite oxide can be regulated by regulating the preparation process parameters of the lithium manganese nickel composite oxide, that is, the E value can be regulated by regulating the preparation process parameters of the lithium manganese nickel composite oxide.
  • a solid phase synthesis method can be used to prepare lithium manganese nickel composite oxide.
  • the specific preparation method includes: providing raw materials for lithium manganese nickel composite oxide, and heat treating the raw materials for lithium manganese nickel composite oxide in an oxygen-containing atmosphere to obtain the lithium manganese nickel composite oxide of any of the above embodiments.
  • the raw materials of lithium manganese nickel composite oxide can be prepared according to the component content of the target lithium manganese nickel composite oxide, and the raw materials used are specifically adjusted according to the type of doping elements.
  • the doped cation is a metal cation
  • the raw material used can be the metal oxide (M b O c ) corresponding to the cation
  • the doped cation is an inorganic cation, it can be the corresponding ammonium salt, carbonate, etc.
  • Li 2 CO 3 , Ni 0.5+z Mn 1.5-xz (OH) 4-2x , M b O c , etc. can be used as the raw materials of lithium manganese nickel elements.
  • the raw material powders are mixed, they are heat treated in an atmosphere containing oxygen to obtain the corresponding lithium manganese nickel composite oxide.
  • the structure of the obtained lithium manganese nickel composite oxide can be stabilized by adjusting the heating temperature, time, reaction atmosphere, etc.
  • S110 Raise the temperature of the raw material of lithium manganese nickel composite oxide to T1, and sinter at temperature T1 to obtain a lithium manganese nickel composite oxide intermediate.
  • 850°C ⁇ T1 ⁇ 1100°C preferably, 900°C ⁇ T1 ⁇ 1000°C.
  • T1 may be 880°C, 930°C, 950°C, 980°C, 1000°C, 1060°C, etc.
  • the sintering time is 2-50h, specifically, the raw material of the lithium manganese nickel composite oxide is heated to T1, and kept at T1 for 2-50h, for example, 8h, 15h, 23h, 31h, 42h, etc.
  • T2 may be 820°C, 850°C, 880°C, 910°C, 960°C, 1000°C, etc.
  • the sintering time is 0.5-20h, specifically, the lithium manganese nickel composite oxide intermediate is heated to T2, and kept at T2 temperature for 0.5-20h, for example, 2h, 5h, 8h, 12h, 15h, 18h, etc.
  • 500°C ⁇ T3 ⁇ 800°C, preferably 600°C ⁇ T3 ⁇ 700°C, for example, T3 may be 520°C, 560°C, 630°C, 680°C, 710°C, 750°C, etc.
  • the annealing time may be 5-30h, specifically, the lithium manganese nickel composite oxide preform may be heated to T3, and kept at T3 for 5-30h, for example, 8h, 14h, 18h, 23h, 27h, etc.
  • the appropriate temperature T1 and its holding time are important parameters to ensure the grain size, oxygen defect content, element distribution, etc.
  • the appropriate temperature T2 and holding time have an important influence on the roundness of the grains, the oxygen defect content and the R value. Annealing is beneficial to reduce the R value, reduce oxygen defects, and improve the stability of the material.
  • the volume median particle size of the obtained material can be regulated to 2 ⁇ m ⁇ D V50 ⁇ 20 ⁇ m, lower oxygen vacancy defects, higher E value, and lower R value.
  • the specific material performance parameters are described in the above embodiment and will not be repeated here.
  • the above steps S120 and S130 are not necessary, and only one or both may be performed; S120 needs to be performed after S110 is cooled to a lower temperature; S130 may be performed after the previous heat treatment process is cooled, or they may be directly combined.
  • the oxygen-containing atmosphere can be air, oxygen, a mixture of air and oxygen, or the like.
  • the present application also provides a positive electrode plate, which includes a positive electrode material and a positive electrode current collector, and the positive electrode material is the lithium manganese nickel composite oxide described in any of the above embodiments.
  • the positive electrode material also includes a positive electrode conductive material, thereby giving the electrode conductivity.
  • the positive electrode conductive material may include any conductive material as long as it does not cause chemical changes.
  • Non-limiting examples of positive electrode conductive materials include carbon-based materials (e.g., natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, etc.), metal-based materials (e.g., metal powder, metal fiber, etc., including, for example, copper, nickel, aluminum, silver, etc.), conductive polymers (e.g., polyphenylene derivatives) and mixtures thereof.
  • the positive electrode current collector may be aluminum (Al).
  • the present application also provides an electrochemical device, which includes any device that generates an electrochemical reaction, and its specific examples include all kinds of primary batteries or secondary batteries.
  • Lithium secondary batteries may include lithium metal secondary batteries, lithium ion secondary batteries, lithium polymer secondary batteries or lithium ion polymer secondary batteries.
  • the battery includes a positive electrode sheet, a separator and a negative electrode sheet.
  • the separator is located between the positive electrode sheet and the negative electrode sheet to perform isolation.
  • the positive electrode sheet includes the positive electrode sheet described in any of the above embodiments.
  • the negative electrode includes a current collector and a negative electrode active material layer disposed on the current collector.
  • the specific types of negative electrode active materials are not subject to specific restrictions and can be selected according to needs.
  • the negative electrode active material is selected from one or more of natural graphite, artificial graphite, mesophase microcarbon beads (referred to as MCMB), hard carbon, soft carbon, silicon, silicon-carbon composite, Li-Sn alloy, Li-Sn-O alloy, Sn, SnO, SnO2 , spinel structured lithiated TiO2 - Li4Ti5O12 , and Li-Al alloy.
  • the electrolyte solvent of the electrolyte includes one or more of fluorocarbonate, fluorocarboxylate, sulfone, and fluoroether.
  • fluorocarbonate, fluorocarboxylate, and sulfone can be selected.
  • the selected electrolyte is a high-voltage resistant electrolyte, which has reduced acidity under high voltage, can significantly reduce surface side reactions, and improve battery stability.
  • the use of the electrochemical device of the present application is not particularly limited, and it can be used for any electronic device known in the prior art. That is, an electrical device is provided, and in some embodiments, the electrochemical device of the present application can be used for, but not limited to, laptop computers, pen-input computers, mobile computers, e-book players, portable phones, portable fax machines, portable copiers, portable printers, head-mounted stereo headphones, video recorders, LCD televisions, portable cleaners, portable CD players, mini-discs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power supplies, motors, cars, motorcycles, power-assisted bicycles, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries and lithium-ion capacitors, etc.
  • lithium-ion batteries The preparation of lithium-ion batteries is described below by taking lithium-ion batteries as an example and combining specific embodiments. Those skilled in the art will understand that the preparation method described in this application is only an example, and any other suitable preparation method is within the scope of this application.
  • the raw material powders corresponding to the stoichiometric ratio are weighed, and the raw material powders are evenly mixed to obtain the raw material mixture powder; the raw material mixture powder is heated to T1 in an air atmosphere, kept at a temperature of t1 time, and then cooled to room temperature to obtain a semi-finished product; the semi-finished product is heated to T2 in an air atmosphere, kept at a temperature of t2 time, and then cooled to room temperature to obtain a preform; the preform is heated to T3 in an air atmosphere, kept at a temperature of t3 time, and then cooled to room temperature to obtain a lithium nickel manganese composite oxide.
  • Tables 1 and 2 The specific target composition, raw materials used and preparation process parameters are detailed in Tables 1 and 2.
  • the positive electrode material is assembled into a button cell. Specifically, lithium nickel manganese composite oxide is mixed with conductive carbon black (Super P) and PVDF in a weight ratio of 90:5:5, and an appropriate amount of solvent N-methylpyrrolidone (NMP) is added, and stirred evenly to obtain a positive electrode slurry. The positive electrode slurry is coated on aluminum foil, dried after coating, and a positive electrode plate is obtained. The loading amount of lithium nickel manganese composite oxide on the positive electrode plate is 0.016g/ cm2 . Provide an electrolyte.
  • a polypropylene film ( ⁇ 16mm) with a thickness of 12 ⁇ m is used as an isolation membrane, and the lithium sheet, isolation membrane, and positive electrode sheet are placed in order so that the isolation membrane is between the metal lithium sheet and the positive electrode plate to play an isolating role. Inject the electrolyte, assemble into a CR2030 button cell, and let it stand for 4h to obtain a button cell.
  • the electrolyte used in Comparative Examples 1-8 and Examples 1-61 is a mixed solution of carbonate and fluorocarbonate containing 1 mol/L LiPF 6 , with the ratio of carbonate to fluorocarbonate being 1:1.
  • the electrolytes used in Comparative Examples 9 and 10 contained only carbonate.
  • the positive electrode active material is assembled into a soft pack battery. Specifically, lithium nickel manganese composite oxide is mixed with conductive carbon black (Super P) and PVDF in a weight ratio of 96:2.5:1.5, and an appropriate amount of solvent N-methylpyrrolidone (NMP) is added, and stirred evenly to obtain a positive electrode slurry. The positive electrode slurry is coated on an aluminum foil, and dried after coating to obtain a positive electrode sheet. The loading of lithium nickel manganese composite oxide on the positive electrode sheet is 0.016g/ cm2 .
  • the negative electrode active material artificial graphite, conductive agent carbon black (Super P), binder styrene butadiene rubber, and thickener sodium carboxymethyl cellulose are fully stirred and mixed in an appropriate amount of solvent deionized water in a mass ratio of 96:1:1:2 to form a uniform negative electrode slurry; the negative electrode slurry is evenly coated on the surface of the negative electrode current collector copper foil, and after drying and cold pressing, a negative electrode sheet is obtained.
  • the loading of the negative electrode active material on a single side of the negative electrode current collector is 0.007g/ cm2 .
  • a mixed solution of carbonate, fluorocarbonate, etc. containing 1 mol/L LiPF 6 is provided as an electrolyte.
  • a polypropylene film with a thickness of 12 ⁇ m is used as an isolating film.
  • the positive electrode sheet, isolating film, and negative electrode sheet prepared above are placed in order so that the isolating film is placed between the positive and negative electrode sheets to play an isolating role.
  • the positive electrode sheet is processed into a shape and packaged in an aluminum-plastic bag.
  • the electrolyte is injected, and the packaging is followed by forming the capacity to obtain a soft-pack battery cell.
  • the electrolyte used in Comparative Examples 1-8 and Examples 1-61 is a mixed solution of carbonate and fluorocarbonate containing 1 mol/L LiPF 6 , with the ratio of carbonate to fluorocarbonate being 1:1.
  • the electrolytes used in Comparative Examples 9 and 10 contained only carbonate.
  • the positive electrode active materials of all embodiments and comparative examples were tested using a ZEISS sigma 300 scanning electron microscope, and then tested in accordance with standard JY/T010-1996 to observe the sample morphology.
  • the laser particle size analyzer diffraction method of GB/T19077-2016 take a clean beaker, add an appropriate amount of the sample to be tested, add a surfactant and then a dispersant. After sufficient dispersion, use a laser particle size analyzer to measure the particle size distribution characteristics (shading degree: 8%-12%).
  • the adsorption amount of gas on the solid surface under different adsorption pressures is measured at a constant low temperature.
  • the monolayer adsorption amount of the sample is obtained based on the BET multilayer adsorption theory and its formula, thereby calculating the specific surface area per unit mass of the solid sample.
  • button cells prepared from the positive electrode active materials of each embodiment/comparative example were charged at a constant current of 0.1 C to a voltage of 4.95 V, and the charging capacity (C1) of 3.5-4.4 V and the charging capacity (C2) of 3.5-4.95 V were intercepted from the original charging data.
  • the charging capacity 4V platform ratio R C1/C2.
  • the prepared soft-pack battery was used as the test object.
  • the soft pack battery is charged at a constant current of 0.3C to a voltage of 4.8V, then charged at a constant voltage of 4.8V to a current of 0.05C, and after standing for 5 minutes, the soft pack battery is discharged at a constant current of 0.33C to a voltage of 3.5V.
  • the discharge energy is the battery discharge energy.
  • the energy divided by the mass of the positive active material in the battery is the initial discharge energy density of the positive active material.
  • the prepared soft-pack battery was used as the test object.
  • the soft-pack battery is charged at a constant current of 0.5C to a voltage of 4.8V, then charged at a constant voltage of 4.8V to a current of 0.05C. After standing for 5 minutes, the soft-pack battery is discharged at a constant current of 0.5C to a voltage of 3.5V. This is a charging cycle process, and the discharge capacity this time is the discharge capacity of the first cycle. After the cyclic charging test is carried out according to the above method, the cycle ends until the discharge capacity decays to 80% of the initial value. The total number of cycles is the high-temperature cycle life.
  • the prepared soft-pack battery was used as the test object.
  • Embodiment 26 Li 2 CO 3 ⁇ Ni 0.5 Mn 1.495 (OH) 3.99 ⁇ NH 4 H 2 PO 4 950 20 // // // // Embodiment 27 Li 2 CO 3 ⁇ Ni 0.5 Mn 1.497 (OH) 3.994 ⁇ NH 4 H 2 PO 4 950 20 // // // // Embodiment 28 Li 2 CO 3 ⁇ Ni 0.5 Mn 1.49 (OH) 3.98 ⁇ NH 4 H 2 PO 4 950 20 // // // // // // // // // // // Embodiment 29 Li 2 CO 3 ⁇ Ni 0.49 Mn 1.48 (OH) 3.94 ⁇ NH 4 H 2 PO 4 950 20 // // // // // // // Embodiment 30 Li 2 CO 3 ⁇ Ni 0.49 Mn 1.47 (OH) 3.92 ⁇ NH 4 H 2 PO 4 950 20 // // // // // Embodiment 31 Li 2 CO 3 ⁇ Ni 0.49 Mn 1.47 (OH) 3.92 ⁇ NH 4 H 2 PO 4 950 20 // // // // // Embodiment 32
  • Table 2 Composition and performance parameters of the positive electrode materials of various embodiments and comparative examples
  • Table 3 Battery performance parameters of various embodiments and comparative examples
  • the battery prepared using this material as the positive electrode active material has good comprehensive performance, specifically, good cyclability, high storage performance, energy density and comprehensive coefficient of electrical performance.
  • Figures 1 and 2 are X-ray diffraction patterns of some embodiments and comparative examples of this application. Specifically including X-ray diffraction patterns of Comparative Example 1, Example 2, Example 3, Example 29, Example 42, and Comparative Example 7. Referring to the data in Tables 2 and 3, the E value of Comparative Example 1 is too small, which makes the stability of the positive electrode material poor, and then leads to poor cyclability and storage performance of the battery, and the comprehensive coefficient of electrical performance also becomes low.
  • regulating the doping of M, N, and Q elements in the lithium manganese nickel composite oxide can also regulate and improve the performance of the battery, and the doping of the M element can cooperate to regulate the E value within a predetermined range.
  • Example 38-58 and Comparative Example 2 the performance of the battery can be improved by adjusting the preparation process of the lithium manganese nickel composite oxide, and the E value can be adjusted within a predetermined range. It can be seen from Example 42 that even high-temperature treatment can achieve an E value within a predetermined range, but the temperature is too high and the energy consumption is large. In other words, even if it is not a preferred process, only adjusting the component content can achieve the regulation of oxide performance.
  • Figure 3 is the first cycle charging curve of the button battery of some embodiments and comparative examples of the present application. Specifically including the first cycle charging curves of comparative example 1, comparative example 2, embodiment 1, and embodiment 4. Referring to the data in Table 2 and Table 3 together, it can be obtained that the 4V platform ratio R value of the positive electrode active material provided by the present application is within a reasonable range, so that the battery has good comprehensive performance.
  • Figure 4 is a morphology of the positive electrode active material of Example 3 of the present application tested by a scanning electron microscope
  • Figure 5 is a morphology of the positive electrode active material of Example 36 of the present application tested by a scanning electron microscope
  • Figure 6 is a morphology of the positive electrode active material of Example 46 of the present application tested by a scanning electron microscope
  • Figure 7 is a morphology of the positive electrode active material of Example 47 of the present application tested by a scanning electron microscope
  • Figure 8 is a morphology of the positive electrode active material of Comparative Example 1 of the present application tested by a scanning electron microscope.
  • the positive electrode active material provided in the present application includes single crystal particles.
  • the surface of the single crystal particles are relatively stable crystal planes, the specific surface area is small, and the probability of cracking and exposing unstable surfaces during processing and service is smaller, which is conducive to slowing down surface side reactions; compared with polycrystalline particles of the same grain size, single crystals are more conducive to dynamic performance due to their small particles and are also not easy to crack.

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Abstract

一种锂锰镍复合氧化物及其制备方法、正极极片、电池和用电装置。锂锰镍复合氧化物的晶型为尖晶石型，锂锰镍复合氧化物的X射线衍射谱图中(111)峰的峰强度I 111与(400)峰的峰强度 I 400的比值2.1≤I 111/I 4 00≤3.3，其中(111)峰为衍射角2θ=18 °-19.5 °的峰，(400)峰为衍射角2θ=43.5 °-45 °的峰。锂锰镍复合氧化物具有较高的稳定性，可以提高电池的综合性能。

Description

锂锰镍复合氧化物及其制备方法、极片、电池、用电装置 技术领域
本申请涉及新能源技术领域，特别是涉及锂锰镍复合氧化物及其制备方法、正极极片、电池、用电装置。
背景技术
锂离子电池具有电压高、重量轻、循环寿命长、无记忆效应、安全性好等优点，可广泛应用于移动电话、数码相机、笔记本电脑等数码产品和电动车、混合电动车等动力工具。锂离子电池包括正极材料、负极材料、隔离膜、电解液和集流体等。其中，正极材料是制约锂离子电池整体性能及成本的关键。尖晶石型锂锰镍复合氧化物可作为正极材料应用到电池中，但是尖晶石型锂锰镍复合氧化物具有较高的脱嵌锂电位，使得正极材料与电解液发生严重的副反应，电解液被消耗产生大量气体，导致增大电芯鼓胀风险且加速容量衰减。与此同时，正极材料因发生副反应而发生离子溶解，其中Mn 2+溶解较多，且溶解的Mn 2+会沉积到负极表面，破坏SEI膜(Solid Electrolyte Interface，固体电解质界面膜)，加速负极及电池的容量衰减。
发明内容
本申请主要解决的技术问题是提供一种尖晶石型锂锰镍复合氧化物及其制备方法、正极极片、电池和用电装置，能够提高正极活性材料的稳定性，进而提高电池的容量。
为解决上述技术问题，本申请采用的一个技术方案是：提供一种尖晶石型锂锰镍复合氧化物，锂锰镍复合氧化物的晶型为尖晶石型，锂锰镍复合氧化物的X射线衍射谱图中(111)峰的峰强度I 111与(400)峰的峰强度I 400的比值2.1≤I 111/I 400≤3.3，其中(111)峰为衍射角2θ＝18°-19.5°的峰，(400)峰为衍射角2θ＝43.5°-45°的峰。
在一些实施方式中，锂锰镍复合氧化物的平均化学成分为Li 1+aM xNi 0.5+zMn 1.5-x-zO 4-k，其中，0<a≤0.3，0<x≤0.2，-0.3≤z≤0.3，0≤k≤0.2，M包括Na、Si、P、S、Nb、Mo、Ru、Te、Ce、Ta、W中的一种或多种元素。
在一些实施方式中，锂锰镍复合氧化物的平均化学成分为Li 1+aM xN yNi 0.5+zMn 1.5-x-y-zO 4-k-qQ q，其中，0<a≤0.3，0<x≤0.2，0≤y≤0.3，-0.3≤z≤0.3，0≤k≤0.2，0≤q≤0.5，M包括Na、Si、P、S、Nb、Mo、Ru、Te、Ce、Ta、W中的一种或多种元素，N包括Mg、Al、K、Sc、Ti、V、Cr、Fe、Co、Rb、Sr、Y、Zr、Rh、Sb、La、Sm、Gd、Yb、Lu、Hf中的一种或多种元素，Q包括F、Cl、Br、I中的一种或多种元素。
在一些实施方式中，1≤a/x≤20。
在一些实施方式中，0.03≤a≤0.15。
在一些实施方式中，0.002≤x≤0.1。
在一些实施方式中，锂锰镍复合氧化物的X射线衍射谱图中在衍射角2θ＝21.5°-24°之间至少存在一个峰，衍射角2θ＝21.5°-24°之间的最强峰与(111)峰的强度的比值0<I (21.5°-24°)/I 111≤3％。
在一些实施方式中，在以锂锰镍复合氧化物为正极材料，以Li为负极材料的电池中，当以0.1C充电倍率的充电条件下，电池在3.5-4.4V区间的充电容量与在3.5-4.95V区间的总充电容量的比值小于或等于15％。
在一些实施方式中，0<x+y+z≤0.3。
在一些实施方式中，2.4≤I 111/I 400≤2.8；2≤a/x≤10；0.05≤a≤0.12；0.01≤x≤0.06；0.005≤y≤0.05；0.01≤z≤0.1；0.01≤x+y+z≤0.1；0.01≤q≤0.1；0≤k≤0.1。
在一些实施方式中，锂锰镍复合氧化物包括单晶颗粒、类单晶颗粒、二次颗粒中的一种或多种。
在一些实施方式中，单个二次颗粒中所含的晶粒数量1≤n≤8。
在一些实施方式中，晶粒外形包括类球形、八面体、八面体削尖去棱的规则外形、棱角圆润的八面体和/或棱角圆润的八面体削尖去棱的多面体规则外形中的一种或多种。
在一些实施方式中，锂锰镍复合氧化物的体积中值粒径2μm≤D V50≤20μm。
在一些实施方式中，锂锰镍复合氧化物的粉体酸碱度10≤pH≤12。
在一些实施方式中，锂锰镍复合氧化物的比表面积0<BET≤0.8m 2/g。
为解决上述技术问题，本申请采用的另一个技术方案是：提供一种正极极片，包括正极材料和正极集流体，正极材料包括上述任一项的锂锰镍复合氧化物。
为解决上述技术问题，本申请采用的另一个技术方案是：提供一种电池，包括：正极极片、隔离膜以及负极极片，隔离膜处于正积极片与负极极片之间起到隔离的作用，正极极片包括上述任一项的正极极片。
在一些实施方式中，电池还包括电解液，电解液的电解液溶剂包括氟代碳酸酯、氟代羧酸酯、砜类、氟代醚中的一种或多种。
为解决上述技术问题，本申请采用的另一个技术方案是：提供一种锂锰镍复合氧化物的制备方法，包括：提供锂锰镍复合氧化物的原料；将锂锰镍复合氧化物的原料在含氧气的氛围下进行热处理，得到上述任一项的锂锰镍复合氧化物。
在一些实施方式中，将锂锰镍复合氧化物的原料在含氧气的氛围下进行热处理包括：将锂锰镍复合氧化物的原料升温至T1，保温2-50h，得到锂锰镍复合氧化物中间体；其中，850℃≤T1≤1100℃。
在一些实施方式中，锂锰镍复合氧化物的制备方法还包括：将锂锰镍复合氧化物中间体升温至T2，保温0.5-20h，得到锂锰镍复合氧化物预制体；其中T1-200℃≤T2≤T1且T2≥800℃。
在一些实施方式中，锂锰镍复合氧化物的制备方法还包括：将锂锰镍复合氧化物预制体升温至T3，保温5-30h，得到锂锰镍复合氧化物；其中，500℃≤T3≤800℃。
在一些实施方式中，提供锂锰镍复合氧化物的原料包括：按照目标成分Li 1+aM xNi 0.5+zMn 1.5-x-zO 4-k提供化学计量比的Li 2CO 3、Ni 0.5+zMn 1.5-x-z(OH) 4-2x、M bO c粉体，混合均匀，得到锂锰镍复合氧化物的原料，其中，0<a≤0.3，0＜x≤0.2，-0.3≤z≤0.3，0≤k≤0.2，M包括钠(Na)、硅(Si)、磷(P)、硫(S)、铌(Nb)、钼(Mo)、钌(Ru)、碲(Te)、铈(Ce)、钽(Ta)、钨(W)中的一种或多种元素。
本申请的有益效果是：区别于现有技术的情况，本申请通过调控尖晶石型锂锰镍复合氧化物的特征峰强度比值I 111/I 400在一优选范围内，能够提高锂锰镍复合氧化物的结构稳定性，进而降低其作为正极材料时与电解液反应的活性，提高电池的整体性能。
附图说明
图1是本申请部分实施例和对比例的X射线衍射图谱；
图2是本申请部分实施例和对比例的X射线衍射图谱；
图3是本申请部分实施例和对比例的扣式电池的首圈充电曲线；
图4是本申请实施例3的正极活性材料用扫描电镜测试的形貌图；
图5是本申请实施例36的正极活性材料用扫描电镜测试的形貌图；
图6是本申请实施例46的正极活性材料用扫描电镜测试的形貌图；
图7是本申请实施例47的正极活性材料用扫描电镜测试的形貌图；
图8是本申请对比例1的正极活性材料用扫描电镜测试的形貌图。
具体实施方式
为使本申请的目的、技术方案及效果更加清楚、明确，以下参照附图并举实施例对本申请进一步详细说明。
如本文中所使用，术语“约”用以描述及说明小的变化。当与事件或情形结合使用时，所述术语可指代其中事件或情形精确发生的例子以及其中事件或情形极近似地发生的例子。举例来说，当结合数值使用时，术语可指代小于或等于所述数值的±10％的变化范围，例如小于或等于±5％、小于或等于±4％、小于或等于±3％、小于或等于±2％、小于或等于±1％、小于或等于±0.5％、小于或等于±0.1％、或小于或等于±0.05％。另外，有时在本文中以范围格式呈现量、比率和其它数值。应理解，此类范围格式是用于便利及简洁起见，且应灵活地理解，不仅包含明确地指定为范围限制的数值，而且包含涵盖于所述范围内的所有个别数值或子范围，如同明确地指定每一数值及子范围一般。
在具体实施方式及权利要求书中，由术语“中的至少一种”连接的项目的列表可意味着所列项目的任何组合。例如，如果列出项目A及B，那么短语“A及B中的至少一种”意味着仅A；仅B；或A及B。在另一实例中，如果列出项目A、B及C，那么短语“A、B及C中的至少一种”意味着仅A；或仅B；仅C；A及B(排除C)；A及C(排除B)；B及C(排除A)；或A、B及C的全部。项目A可包含单个元件或多个元件。项目B可包含单个元件或多个元件。项目C可包含单个元件或多个元件。
随着电化学装置(例如，锂离子电池)的广泛应用，人们对其性能的要求越来越高，尤其是电池的安全性、稳定性、容量等，期望电池具备各方面都好的综合性能。锂离子电池包括正极、负极、隔离膜、电解液等。正极包括正极集流体和设置在正极集流体上的正极材料。其中，正极材料是制约锂离子电池整体性能的关键。然而，现有使用的正极材料易与电解液发生严重的副反应，会导致增大电芯鼓胀风险、加速负极容量衰减及电池的容量衰减等问题。通常可通过对正极材料进行表面包覆、对正极材料进行结构调控以减少材料的氧缺陷、增大正极材料的粒径、减少正极材料的比表面积、对正极材料进行表面修饰以稳定材料表面及减少电解液与正极材料接触等多种手段来改善目前存在的问题。然而这些手段仍然存在一定的弊端。
为了解决上述技术问题，本申请选用尖晶石型锂锰镍复合氧化物作为正极材料，并调控锂锰镍复合氧化物的晶体结构、元素成分和含量以及制备工艺等方式来改善锂锰镍复合氧化物的性能，提高锂锰镍复合氧化物向更稳定结构生长的热力学趋势和生长动力，从而提升锂锰镍复合氧化物的结构稳定性，进而能够显著改善锂锰镍复合氧化物作为正极材料应用于电池中的综合性能，具体地，可以提高电池容量。其中，锂锰镍复合氧化物是指含锂锰镍的氧化物，即在氧化物中除锂锰镍之外还可以包括其他元素，因此，又称含锂锰镍复合氧化物。
在一些实施方式中，锂锰镍复合氧化物的晶型为尖晶石型，锂锰镍复合氧化物的X射线衍射谱 图中(111)峰的峰强度I 111与(400)峰的峰强度I 400的比值2.1≤I 111/I 400≤3.3，(111)峰为衍射角2θ＝18°-19.5°的峰，(400)峰为衍射角2θ＝43.5°-45°的峰。
其中，可依据标准JIS K 0131-1996，使用CuKα1射线的粉末X射线衍射仪来测试锂锰镍复合氧化物。在X射线衍射(XRD)谱图中，(111)峰(峰位置2θ＝18°-19.5°)为锂锰镍复合氧化物晶体择优生长基面的峰，(400)峰(峰位置2θ＝43.5°-45°)为锂锰镍复合氧化物晶体生长端面的峰。此处的端面是理论上生长的端面。通过调控锂锰镍复合氧化物的特征峰强度比值在这一范围内，能够提高锂锰镍复合氧化物的结构稳定性，进而降低其作为正极材料时与电解液反应的活性，提高电池的整体性能。
在一实施方式中，尖晶石型含锂锰镍复合氧化物的第一择优生长晶面为(111)面，即原子沿(111)面一层一层铺展长大，所以(111)面的堆积质量决定了晶体结构的稳定性。一个尖晶石型含锂锰镍复合氧化物晶粒可同时有多个(111)面(如八面体晶粒外形中的八个侧面)各自生长，晶面相互接触后形成(a00)侧面。因此(111)面可以称之为尖晶石结构的“基面”，(a00)面可以称之为尖晶石结构的“端面”。在XRD谱图中，基面(111)的峰强度与端面(a00)的峰强度之比E＝I 111/I a00，E可以表明晶面(111)的择优程度；E值越大，说明(111)面的择优程度越大，则(111)面的能量越低，从而(111)面堆积的更顺畅，尖晶石型含锂锰镍复合氧化物的整体结构越稳定，进而使得使用该材料的电池的稳定性提升。但当E值过大时，晶体结构过于稳定，会导致锂离子(Li +)脱嵌变得困难，不利于电池的动力学性能和容量发挥。因此，E也可以称之为晶面择优指数，来表征晶体结构的稳定性。在常规XRD谱图中，(111)峰和(400)峰为强度较大的三个强峰中的两个，本申请中选择(111)峰和(400)峰作为特征峰考量E值，即E＝I 111/I 400。
在一优选实施方式中，2.3≤I 111/I 400≤3.0；进一步优选地，2.4≤I 111/I 400≤2.8。例如I 111/I 400可以是2.2、2.5、2.6、2.7、2.9等。通过控制晶面择优指数E值在这个范围内，能够在满足电池动力学性能和容量需求的基础上，降低锂锰镍复合氧化物与电解液反应的活性，以提高电池的稳定性。
在一些实施方式中，可以通过调控锂锰镍复合氧化物中所含元素的成分和含量来调控锂锰镍复合氧化物的晶体生长方向和结构稳定性。即可通过调控锂锰镍复合氧化物中所含元素的成分和含量来调控E值。
在一些实施方式中，锂锰镍复合氧化物的平均化学成分为Li 1+aM xNi 0.5+zMn 1.5-x-zO 4-k，其中，0＜a≤0.3，0＜x≤0.2，-0.3≤z≤0.3，0≤k≤0.2，M包括钠(Na)、硅(Si)、磷(P)、硫(S)、铌(Nb)、钼(Mo)、钌(Ru)、碲(Te)、铈(Ce)、钽(Ta)、钨(W)中的一种或多种元素。
其中，本申请所提供锂锰镍复合氧化物中，增大氧化物中的Li含量，即Li位与Ni/Mn位元素的摩尔含量的比值＞0.5。通过增大Li含量有利于尖晶石型含锂锰镍复合氧化物具有向稳定结构生长的热力学趋势。具体地，Li含量的增加可促进尖晶石结构中Mn价态提升，提高Mn-O键结合强度，降低尖晶石型含锂锰镍复合氧化物与电解液的副反应，即所增加的Li可适量进入Mn位形成Li掺杂，提高材料的结构稳定性，进而降低与电解液的副反应。但是尖晶石型含锂锰镍复合氧化物向稳定结构生长的热力学趋势与生长动力(即生长的动力学趋势)之间存在矛盾。因此，Li含量增加会降低(111)面的择优程度，即降低E值，降低尖晶石型含锂锰镍复合氧化物生长为稳定结构的动力。或者说，通过增大Li含量一方面能够提高尖晶石型含锂锰镍复合氧化物向稳定结构生长的热力学趋势，另一方面会降低尖晶石型含锂锰镍复合氧化物向稳定结构生长的动力，即降低动力学趋势。
进一步地，本申请在锂锰镍复合氧化物中引入M元素来改性锂锰镍复合氧化物，以调和尖晶石型含锂锰镍复合氧化物向稳定结构生长的热力学趋势与生长动力之间的矛盾，从而实现尖晶石型含锂锰镍复合氧化物结构的稳定性显著提升。或者说M元素的掺杂能够提高尖晶石型含锂锰镍复合氧化物向稳定结构生长的动力，以弥补Li含量增加带来的生长动力的减弱。
在一些实施方式中，M包括钠(Na)、硅(Si)、磷(P)、硫(S)、铌(Nb)、钼(Mo)、钌(Ru)、碲(Te)、铈(Ce)、钽(Ta)、钨(W)中的一种或多种元素。优选地，M包括Si、P、Ru、Te、Ce、Ta中的一种或多种元素；进一步优选地，M包括P、Ru、Te、Ta中的一种或多种元素。M元素可分 布在尖晶石型含锂锰镍复合氧化物的体相内或者分布在材料的表面。
该实施方式中，所选M元素一方面可稳定尖晶石型含锂锰镍复合氧化物的晶体结构，另一方面还能捕获电解液中的氟化氢(HF)，且发生副反应的产物对电池体系无害，显著提升电池的整体性能。
在一些实施方式中，M元素的掺杂量x需与Li含量的a匹配才能更好的兼顾晶体生长的热力学趋势和动力学趋势，即兼顾Li的含量和E值。一定程度上，可以是Li越多就需要掺杂越多的元素M来调和。
在一些实施方式中，1≤a/x≤20。在一些优选实施方式中，2≤a/x≤10。例如a/x可以是4、6、8、11、12、15、17、19等。
在一些实施方式中，0.03≤a≤0.15；优选地，0.05≤a≤0.12。例如a可以是0.04、0.06、0.08、0.09、0.11、0.13、0.14等。
在一些实施方式中，0.002≤x≤0.1；优选地，0.01≤x≤0.06。例如x可以是0.005、0.008、0.02、0.04、0.05、0.08、0.09等。
该实施方式中，通过控制M元素掺杂量以及Li含量在此范围内，能够使改善效果最优，且可兼顾电池容量、动力学性能和使用该材料的电池的长期使用性能，例如延长电池的使用寿命。
在一些实施方式中，锂锰镍复合氧化物的平均化学成分为Li 1+aM xN yNi 0.5+zMn 1.5-x-y-zO 4-k-qQ q，其中，0＜a≤0.3，0＜x≤0.2，0≤y≤0.3，-0.3≤z≤0.3，0≤k≤0.2，0≤q≤0.5，M包括Na、Si、P、S、Nb、Mo、Ru、Te、Ce、Ta、W中的一种或多种元素，N包括镁(Mg)、铝(Al)、钾(K)、钪(Sc)、钛(Ti)、钒(V)、铬(Cr)、铁(Fe)、钴(Co)、铷(Rb)、锶(Sr)、钇(Y)、锆(Zr)、铑(Rh)、锑(Sb)、镧(La)、钐(Sm)、钆(Gd)、镱(Yb)、镥(Lu)、铪(Hf)中的一种或多种元素，Q包括氟(F)、氯(Cl)、溴(Br)、碘(I)中的一种或多种元素。N、Q元素可分布在尖晶石型含锂锰镍复合氧化物的体相内或者分布在材料的表面。
其中，N元素为可进入Li位和/或Mn位和/或Ni位的元素。在一些优选实施方式中，N包括K、Rb、Sr、Y、Rh、Sb、La、Sm、Gd、Yb、Lu、Hf中的一种或多种元素。
该实施方式中，N元素作为其他阳离子掺杂进尖晶石型含锂锰镍复合氧化物，通过引入这几种元素，有利于E达到需求范围，提高尖晶石型含锂锰镍复合氧化物结构的稳定性、减缓材料与电解液的副反应，其中优选元素的改善效果最明显。
在一些优选实施方式中，0＜y≤0.3，进一步优选地，0.001≤y≤0.1，更优选地，0.005≤y≤0.05。例如y可以是0.003、0.008、0.01、0.07、0.13、0.19、0.25等。通过控制N元素的掺杂量在此范围内时改善效果最优，且可兼顾电池容量、动力学性能和使用该材料的电池的长期使用性能。
在一些优选实施方式中，0.01≤z≤0.1。例如z可以是0.02、0.03、0.04、0.05、0.06、0.07、0.08等。即Ni含量也是增加的，增加的Ni有利于提高Mn的平均价态、稳定结构，增加的Ni还可在晶粒表面形成岩盐相，保护富锰体相，减少Mn溶出概率。
在一些优选实施方式中，0＜x+y+z≤0.3；进一步优选地0.005≤x+y+z≤0.2；更优选地0.01≤x+y+z≤0.1。例如x+y+z可以是0.008、0.03、0.06、0.09、0.16、0.21、0.27等。该实施方式中，限制了阳离子总掺杂量；通过控制阳离子总掺杂量在此范围内可兼顾材料的容量、动力学性能和使用该材料电池的使用寿命。
在一些优选实施方式中，0＜q≤0.5，进一步优选地0.001≤q≤0.2，更优选地0.01≤q≤0.1。例如q可以是0.006、0.03、0.07、0.13、0.18、0.24、0.33、0.42等。能够控制阴离子的掺杂量，阴离子在此范围内时改善效果最优。
在一些优选实施方式中，0≤k≤0.1。例如k可以是0.003、0.005、0.007、0.009等。通过控制氧的含量，能够降低材料的氧缺陷，氧缺陷的降低有利于提高材料的结构稳定性，减缓材料与电解液的副反应。
在一些实施方式中，锂锰镍复合氧化物的X射线衍射谱图中在衍射角2θ＝21.5°-24°之间至少存在 一个峰，衍射角2θ＝21.5°-24°之间的最强峰与(111)峰的强度的比值0＜I (21.5°-24°)/I 111≤3％；优选地0.2％≤I (21.5°-24°)/I 111≤2％，更优选地0.5％≤I (21.5°-24°)/I 111≤1.5％。例如I (21.5°-24°)/I 111可以是0.3％、0.8％、1.2％、1.7％、2.6％等。
其中，通过调控改性元素(M元素、N元素和Q元素)的种类、元素分布、元素的掺杂量等能够调控21.5°-24°之间的峰的出峰位置和峰强度。本申请发明人研究发现21.5°-24°之间的峰的峰强越高、越有利于延长使用该材料的电池的使用寿命，但峰强超过一定值后电池容量急剧下降且寿命恶化。因此，本申请方案中，在调控锂锰镍复合氧化物中各元素的掺杂类型和掺杂量时，需同时考虑E值以及21.5°-24°之间的峰与(111)峰的强度的比值，以调控电池的综合性能更好。所得较优的材料成分、含量详见上文描述。
在一些实施方式中，在以锂锰镍复合氧化物为正极材料，以Li为负极材料的电池中，当以0.1C充电倍率的充电条件下，电池在3.5-4.4V区间的充电容量与在3.5-4.95V区间的总充电容量的比值R小于或等于15％；优选地，R小于或等于10％；更优选地，4％≤R≤10％。例如R可以是1％、3％、5％、6％、7％、8％、9％、12％、14％等。
其中，在以尖晶石型含锂锰镍复合氧化物材料为正极材料、以Li为负极材料的扣式电池中，以0.1C的小倍率电流恒流充电，其中3.5-4.4V区间的充电容量与3.5-4.95V区间的总充电容量的比值称之为4V平台占比。4V平台占比R越大表明了Mn 3+含量越多，也意味着平均充放电电压降低。Mn 3+含量增多会增大Mn溶出风险，平均放电电压降低意味着能量密度降低。因此，需调控R值不能太大。但是，本申请发明人研究发现，当尖晶石型含锂锰镍复合氧化物的E值增大时往往伴随着R增大。为平衡两个数值，调控电池的综合性能较高。本申请发明人进一步研究发现，调控M元素的掺杂种类和掺杂量，能够平衡E值和R值，合理调控M元素的掺杂种类和掺杂量能够使得E值增大但R值不增大甚至减小。进而得到较优的材料成分，具体成分含量详见上文描述。
在一些实施方式中，锂锰镍复合氧化物包括单晶颗粒、类单晶颗粒、二次颗粒中的一种或多种。
其中，单晶的结晶体内部的微粒在三维空间呈有规律地、周期性地排列，或者说晶体的整体在三维方向上由同一空间格子构成，整个晶体中质点在空间的排列为长程有序。单晶颗粒又称一次颗粒，一次颗粒可团聚形成二次颗粒，当一个二次颗粒仅含少数几个或十几个晶粒时就称之为类单晶颗粒。
在一些实施方式中，锂锰镍复合氧化物的晶粒外形包括类球形、八面体、八面体削尖去棱的规则外形、棱角圆润的八面体和/或棱角圆润的八面体削尖去棱的多面体规则外形中的一种或多种；优选地，晶粒外形为棱角圆润的八面体和/或棱角圆润的八面体削尖去棱的多面体规则外形。
其中，八面体和八面体削尖去棱的多面体规则外形的晶粒表面为更有利于Li +传导的晶面，因此容量和动力学性能发挥较优；类球形的晶粒可减缓因应力集中而导致的开裂和易被腐蚀，因此材料后续的加工性能和使用其的电池的长期使用寿命较优。圆润的八面体和/或棱角圆润的八面体削尖去棱的多面体规则外形则兼顾了前两类的优点，兼顾了材料的容量、动力学性能和长期使用稳定性。
在一些实施方式中，锂锰镍复合氧化物还包括二次颗粒，单个二次颗粒中所含的晶粒数量1≤n≤8，优选1≤n≤3。例如n可以是2、4、5、6、7等。
其中，尖晶石型含锂锰镍复合氧化物颗粒表面是副反应集中的区域。尖晶石型含锂锰镍复合氧化物的晶粒表面是Ni/Mn及Ni/Mn位元素最稳定的晶面，而固溶在尖晶石型含锂锰镍复合氧化物中的M元素主要进入Ni/Mn位。所以单晶颗粒中，进入晶格的M元素最稳定，含M元素的表面包覆物也能与基材表面良好匹配，从而将M元素的改性效果发挥到最佳。
此外，相对于同颗粒尺寸的多晶，单晶颗粒表面都是较为稳定的晶面、比表面积小、加工和服役过程开裂暴露不稳定表面的概率更小，有利于减缓表面副反应；相比于同晶粒尺寸的多晶，单晶因为颗粒小而更有利于动力学性能，同样不易开裂。
在一些实施方式中，锂锰镍复合氧化物的体积中值粒径2μm≤D V50≤20μm；优选地，3μm≤D V50≤15μm，更优选地，5μm≤D V50≤10μm。例如D V50可以是4μm、6μm、8μm、13μm、18μm等。当粒径 控制在此优化范围内时，能更好的调控单晶、氧缺陷、比表面积等参数。
在一些实施方式中，锂锰镍复合氧化物的粉体酸碱度10≤pH≤12。相较于常规尖晶石型含锂锰镍复合氧化物的pH为7-10，本申请的尖晶石型含锂锰镍复合氧化物的碱性更强，可与高电压下产生的强酸中和，减少正极材料表面破坏；碱性过强则不利于加工性能，容易吸潮、与粘结剂反应等恶化电池性能。
在一些实施方式中，锂锰镍复合氧化物的比表面积0＜BET≤0.8m 2/g；优选地，0＜BET≤0.5m 2/g，更优选地，0.1≤BET≤0.4m 2/g。例如可以是0.2m 2/g、0.3m 2/g、0.6m 2/g、0.7m 2/g等，比表面积可以使用气体吸附法测得比表面积。较小的比表面积可减缓表面副反应。但比表面积受包覆状态的影响大，如纳米颗粒物包覆会显著增大比表面积，但活性比表面积其实是减小的。
在一些实施方式中，可以通过调控锂锰镍复合氧化物的制备工艺参数来调控锂锰镍复合氧化物的晶体生长方向和结构稳定性。即可通过调控锂锰镍复合氧化物的制备工艺参数来调控E值。
在一些实施方式中，可以使用固相合成法制备锂锰镍复合氧化物，具体制备方法包括：提供锂锰镍复合氧化物的原料，将锂锰镍复合氧化物的原料在含氧气的氛围下进行热处理，得到上述任一实施例的锂锰镍复合氧化物。
其中，可以按照目标锂锰镍复合氧化物的成分含量准备锂锰镍复合氧化物的原料，所用原料具体根据掺杂元素的种类适应调整。如所掺杂阳离子为金属阳离子时，所用原料可以是该阳离子对应的金属氧化物(M bO c)；所掺杂阳离子为无机阳离子时，可以是对应的铵盐、碳酸盐等，可以使用Li 2CO 3、Ni 0.5+zMn 1.5-x-z(OH) 4-2x、M bO c等作为锂锰镍元素的原料。
各原料粉体混合后，在含氧气的氛围下进行热处理，得到相应的锂锰镍复合氧化物。其中，可以通过调控加热的温度、时间、反应的气氛等，使得所得锂锰镍复合氧化物结构稳定。
在一些实施方式中，锂锰镍复合氧化物的制备方法包括：
S110：将锂锰镍复合氧化物的原料升温至T1，在温度T1下烧结，得到锂锰镍复合氧化物中间体。
S120：将锂锰镍复合氧化物中间体升温至T2，在温度T2下烧结，得到锂锰镍复合氧化物预制体。
S130：将锂锰镍复合氧化物预制体升温至T3，进行退火处理，得到锂锰镍复合氧化物。
在一些实施方式中，850℃≤T1≤1100℃，优选地，900℃≤T1≤1000℃。例如T1可以是880℃、930℃、950℃、980℃、1000℃、1060℃等。烧结时间为2-50h，具体可以是将锂锰镍复合氧化物的原料升温至T1，在T1温度下保温2-50h，例如可以是8h、15h、23h、31h、42h等。
在一些实施方式中，T1-200℃≤T2≤T1且T2≥800℃；优选地，850+(T1-900)/4℃≤T2≤T1-(T1-900)/4℃。例如T2可以是820℃、850℃、880℃、910℃、960℃、1000℃等。烧结时间为0.5-20h，具体可以是将锂锰镍复合氧化物中间体升温至T2，在T2温度下保温0.5-20h，例如可以是2h、5h、8h、12h、15h、18h等。
在一些实施方式中，500℃≤T3≤800℃，优选600℃≤T3≤700℃，例如T3可以是520℃、560℃、630℃、680℃、710℃、750℃等。退火时间可以是5-30h，具体可以是将锂锰镍复合氧化物预制体升温至T3，在T3温度下保温5-30h，例如可以是8h、14h、18h、23h、27h等。
其中，合适的温度T1及其保温时间是确保晶粒大小、氧缺陷含量、元素分布等的重要参数。合适的温度T2和保温时间是对晶粒的圆润程度和氧缺陷含量及R值有重要影响。退火有利于降低R值，降低氧缺陷，提高材料稳定性。该实施方式中，通过合理调控T1、T2和T3的温度范围，以及步骤S110、S120和S130的反应时间，能够调控所得材料的体积中值粒径2μm≤D V50≤20μm，较低的氧空位缺陷，较高的E值，较低的R值，具体材料性能参数详见上述实施方式的描述，在此不再赘述。
在一些实施方式中，上述步骤S120和S130是非必须的，可仅有其一或皆无；S120需在S110后冷却至较低温度后再进行；S130可在其前的热处理工序冷却后再进行，也可直接合并进行。
在一些实施方式中，含氧气氛可以是空气、氧气、空气氧气混合等。
本申请还提供一种正极极片，正极极片包括正极材料和正极集流体，正极材料为上述任一实施方 式所述的锂锰镍复合氧化物。
在一些实施方式中，正极材料还包括正极导电材料，从而赋予电极导电性。正极导电材料可以包括任何导电材料，只要它不引起化学变化。正极导电材料的非限制性示例包括基于碳的材料(例如，天然石墨、人造石墨、碳黑、乙炔黑、科琴黑、碳纤维等)、基于金属的材料(例如，金属粉、金属纤维等，包括例如铜、镍、铝、银等)、导电聚合物(例如，聚亚苯基衍生物)和它们的混合物。在一些实施例中，正极集流体可以是铝(Al)。
本申请还提供一种电化学装置，电化学装置包括发生电化学反应的任何装置，它的具体实例包括所有种类的一次电池或二次电池。锂二次电池可包括锂金属二次电池、锂离子二次电池、锂聚合物二次电池或锂离子聚合物二次电池。
在一些实施方式中，电池包括正极极片、隔离膜以及负极极片，隔离膜处于正极极片与负极极片之间起到隔离的作用，正极极片包括上述任一实施方式所述的正极极片。
在一些实施方式中，负极包括集流体和设置在集流体上的负极活性材料层。负极活性材料的具体种类均不受到具体的限制，可根据需求进行选择。例如，负极活性材料选自天然石墨、人造石墨、中间相微碳球(简称为MCMB)、硬碳、软碳、硅、硅-碳复合物、Li-Sn合金、Li-Sn-O合金、Sn、SnO、SnO2、尖晶石结构的锂化TiO 2-Li 4Ti 5O 12、Li-Al合金中的一种或几种。
在一些实施方式中，电解液的电解液溶剂包括氟代碳酸酯、氟代羧酸酯、砜类、氟代醚中的一种或多种。可选氟代碳酸酯、氟代羧酸酯、砜类中的一种或多种。所选电解液为耐高压电解液，其在高电压下的酸性减弱，能够明显降低表面副反应，提高电池稳定性。
在一些实施方式中，本申请的电化学装置的用途没有特别限定，其可用于现有技术中已知的任何电子装置。即提供一种用电装置，在一些实施例中，本申请的电化学装置可用于，但不限于，笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池和锂离子电容器等。
下面以锂离子电池为例并且结合具体的实施例说明锂离子电池的制备，本领域的技术人员将理解，本申请中描述的制备方法仅是示例，其他任何合适的制备方法均在本申请的范围内。
1.正极的制备
正极活性材料的制备
按正极活性材料的目标成分称取对应化学计量比的原料粉体，将原料粉体混合均匀，得到原料混合物粉体；将原料混合物粉体在空气气氛中，升温到T1保温t1时间后冷却至室温得到半成品；将半成品在空气气氛中，升温到T2保温t2时间后冷却至室温得到预制品，将预制品在空气气氛中，升温到T3保温t3时间后冷却至室温得到锂镍锰复合氧化物。具体目标成分、所用原料及制备工艺参数详见表1和表2。
2.电池(扣式电池)的组装
以锂片为对电极，将正极材料组装为扣式电池。具体地，将锂镍锰复合氧化物与导电炭黑(Super P)、PVDF按重量比90:5:5混合，加入适量溶剂N-甲基吡咯烷酮(NMP)，搅拌均匀，获得正极浆料。将正极浆料涂布在铝箔上，涂布后烘干，获得正极极片。正极极片上锂镍锰复合氧化物的负载量为0.016g/cm 2。提供电解液。以厚度12μm的聚丙烯薄膜(Φ16mm)作为隔离膜，将锂片、隔离膜、正极片按顺序放好，使隔离膜处于金属锂片与正极极片中间起到隔离的作用。注入电解液，组装成CR2030扣式电池，静置4h，得扣式电池。
其中，对比例1-8和实施例1-61所用电解液为含有1mol/L LiPF 6的碳酸脂、氟代碳酸脂的混合溶液，碳酸脂:氟代碳酸脂＝1:1。
对比例9和10所用电解液仅包含碳酸脂。
3.软包电池的制作
将正极活性材料组装为软包电池。具体地，将锂镍锰复合氧化物与导电炭黑(Super P)、PVDF按重量比96:2.5:1.5混合，加入适量溶剂N-甲基吡咯烷酮(NMP)，搅拌均匀，获得正极浆料。将正极浆料涂布在铝箔上，涂布后烘干，获得正极极片。正极极片上锂镍锰复合氧化物的载量为0.016g/cm 2。将负极活性材料人造石墨、导电剂炭黑(Super P)、粘结剂丁苯橡胶、增稠剂羧甲基纤维素钠按照质量比96:1:1:2在适量的溶剂去离子水中充分搅拌混合，形成均匀的负极浆料；将负极浆料均匀涂覆于负极集流体铜箔的表面上，经干燥、冷压后，得到负极极片。负极集流体单侧上负极活性材料的负载量为0.007g/cm 2。提供含有1mol/L LiPF 6的碳酸脂、氟代碳酸脂等的混合溶液作为电解液。以厚度12μm的聚丙烯薄膜作为隔离膜，将上述制得的正极极片、隔离膜，负极极片按顺序放好，使隔离膜处于正、负极片中间起到隔离的作用，加工成型，用铝塑袋包装。注入电解液，封装后进行化成容量，制得软包电芯。
其中，对比例1-8和实施例1-61所用电解液为含有1mol/L LiPF 6的碳酸脂、氟代碳酸脂的混合溶液，碳酸脂:氟代碳酸脂＝1:1。
对比例9和10所用电解液仅包含碳酸脂。
4.本申请实施例和对比例的正极活性材料的相关参数测试过程如下：
(1)XRD测试
参照JIS K 0131-1996X射线衍射分析法通则，使用CuKα1射线测定尖晶石型含镍锰锂复合氧化物材料的X射线衍射图谱。
(2)元素含量测试
参照EPA 6010D-2014电感耦合等离子体原子发射光谱法，测量尖晶石型含镍锰锂复合氧化物材料中各元素的含量。
(3)形貌测试
将所有实施例和对比例的正极活性材料用ZEISS sigma 300扫描电子显微镜进行测试，然后参照标准JY/T010-1996进行测试，对样品形貌进行观测。
(4)粒度测试
参照GB/T19077-2016激光粒度仪衍射法，取一洁净烧杯，加入适量待测样品，滴加表面活性剂后添加分散剂，充分分散后，采用激光粒度仪测定颗粒的粒度分布特征(遮光度：8％-12％)。
(5)比表面积测试
按照GB/T 19587-2004气体吸附BET法，将样品加热脱气后，在恒低温度下，测定不同吸附压力下气体在固体表面的吸附量，基于BET多层吸附理论及其公式求得试样单分子层吸附量，从而计算出单位质量固体样品的比表面积。
5.扣电测试与充电4V平台R值计算
在25℃下，将各实施例/对比例的正极活性材料制备的扣式电池以0.1C恒流充电至电压为4.95V，从原始充电数据中截取3.5-4.4V的充电容量(C1)和3.5-4.95V的充电容量(C2)。
充电容量4V平台占比R＝C1/C2。
6.软包电性能测试
(1)正极活性材料在软包电池初始放电能量密度测试
以制备的软包电池为测试对象。
在25℃下，将软包电池以0.3C恒流充电至电压为4.8V，然后以4.8V恒压充电至电流为0.05C，静置5min之后，将软包电池以0.33C恒流放电至电压为3.5V，该放电能量即为电池放电能量。用该能量除以电池中的正极活性物质的质量即为正极活性物质的初始放电能量密度。
(2)软包电池高温循环性能测试
以制备的软包电池为测试对象。
在45℃下，将软包电池以0.5C恒流充电至电压为4.8V，然后以4.8V恒压充电至电流为0.05C，静置5min之后，将软包电池以0.5C恒流放电至电压为3.5V，此为一个充电循环过程，此次的放电容量为首次循环的放电容量。按上述方法进行循环充电测试后，直至放电容量衰减为初始值的80％，则循环结束。循环总圈数即为高温循环寿命。
(3)软包电池高温满充存储性能测试
以制备的软包电池为测试对象。
在25℃下，将软包电池以0.3C恒流充电至电压为4.8V，然后以4.8V恒压充电至电流为0.05C。然后将电池在45℃下放置，每隔10d后满放。接着在25℃下做一次满充满放，提取该放电容量值Cn。再次满充并在45℃环境下继续存储。直至放电容量Cn衰减为初始值的80％，则存储结束。满充后在45℃下存储的总时长即为高温满充存储时长。
表1：各实施例和对比例的制备工艺参数
样品编号 原料成分 T1/℃ t1/h T2/℃ t2/h T3/℃ t3/h
对比例1 Li 2CO 3、Ni 0.5Mn 1.5(OH) 4 950 20 // // 650 20
对比例2 Li 2CO 3、Ni 0.5Mn 1.5(OH) 4 950 20 // // // //
实施例1 Li 2CO 3、Ni 0.5Mn 1.5(OH) 4 950 20 // // // //
实施例2 Li 2CO 3、Ni 0.5Mn 1.5(OH) 4 950 20 // // 650 20
实施例3 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 // // // //
实施例4 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4、TeO 2 950 20 // // // //
实施例5 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、SiO 2 950 20 // // // //
实施例6 Li 2CO 3、Ni 0.5Mn 1.49(OH) 3.98、RuO 2 950 20 // // // //
实施例7 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、CeO 2 950 20 // // // //
实施例8 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4、CeO 2 950 20 // // // //
实施例9 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4、Nb 2O 5 950 20 // // // //
实施例10 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4、Ta 2O 5 950 20 // // // //
实施例11 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4、WO 3 950 20 // // // //
实施例12 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、TeO 2、CeO 2 950 20 // // // //
实施例13 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、Te 2O 5、Ta 2O 5 950 20 // // // //
实施例14 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、Li 2SO 4、WO 3 950 20 // // // //
对比例3 Li 2CO 3、Ni 0.49Mn 1.5(OH) 3.98、Cr 2O 3 950 20 // // // //
实施例14 Li 2CO 3、Ni 0.48Mn 1.47(OH) 3.9、NH 4H 2PO 4、Cr 2O 3 950 20 // // // //
实施例15 Li 2CO 3、Ni 0.48Mn 1.46(OH) 3.88、NH 4H 2PO 4、TeO 2、Al 2O 3 950 20 // // // //
实施例16 Li 2CO 3、Ni 0.48Mn 1.47(OH) 3.9、NH 4H 2PO 4、TeO 2、Sb 2O 5 950 20 // // // //
对比例4 Li 2CO 3、Ni 0.5Mn 1.5(OH) 4、LiF 950 20 // // // //
实施例17 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4、LiF 950 20 // // // //
实施例18 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4、LiI 950 20 // // // //
实施例19 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4、TeO 2、LiF 950 20 // // // //
实施例20 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4、CeO 2、LiF 950 20 // // // //
对比例5 Li 2CO 3、Ni 0.5Mn 1.48(OH) 3.96、Al 2O 3、LiF 950 20 // // // //
实施例21 Li 2CO 3、Ni 0.48Mn 1.47(OH) 3.9、NH 4H 2PO 4、Al 2O 3、LiF 950 20 // // // //
实施例22 Li 2CO 3、Ni 0.48Mn 1.46(OH) 3.88、NH 4H 2PO 4 950 20 // // // //
实施例23 Li 2CO 3、Ni 0.49Mn 1.46(OH) 3.9、NH 4H 2PO 4 950 20 // // // //
实施例24 Li 2CO 3、Ni 0.49Mn 1.48(OH) 3.94、NH 4H 2PO 4 950 20 // // // //
实施例25 Li 2CO 3、Ni 0.5Mn 1.49(OH) 3.98、NH 4H 2PO 4 950 20 // // // //
实施例26 Li 2CO 3、Ni 0.5Mn 1.495(OH) 3.99、NH 4H 2PO 4 950 20 // // // //
实施例27 Li 2CO 3、Ni 0.5Mn 1.497(OH) 3.994、NH 4H 2PO 4 950 20 // // // //
实施例28 Li 2CO 3、Ni 0.5Mn 1.49(OH) 3.98、NH 4H 2PO 4 950 20 // // // //
实施例29 Li 2CO 3、Ni 0.49Mn 1.48(OH) 3.94、NH 4H 2PO 4 950 20 // // // //
实施例30 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 // // // //
实施例31 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 // // // //
实施例32 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 // // // //
对比例6 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 // // // //
实施例33 Li 2CO 3、Ni 0.5Mn 1.498(OH) 3.996、NH 4H 2PO 4 950 20 // // // //
实施例34 Li 2CO 3、Ni 0.5Mn 1.49(OH) 3.98、NH 4H 2PO 4 950 20 // // // //
实施例35 Li 2CO 3、Ni 0.48Mn 1.46(OH) 3.88、NH 4H 2PO 4 950 20 // // // //
实施例36 Li 2CO 3、Ni 0.47Mn 1.43(OH) 3.8、NH 4H 2PO 4 950 20 // // // //
实施例37 Li 2CO 3、Ni 0.45Mn 1.35(OH) 3.6、NH 4H 2PO 4 950 20 // // // //
对比例7 Li 2CO 3、Ni 0.44Mn 1.32(OH) 3.52、NH 4H 2PO 4 950 20 // // // //
对比例8 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 800 20 // // // //
实施例38 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 850 20 // // // //
实施例39 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 900 20 // // // //
实施例40 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 1000 20 // // // //
实施例41 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 1100 20 // // // //
实施例42 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 1200 20 // // // //
实施例43 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 2 // // // //
实施例44 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 50 // // // //
实施例45 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 800 5 // //
实施例46 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 865 2 // //
实施例47 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 935 1 // //
实施例48 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 950 0.5 // //
实施例49 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 865 0.5 // //
实施例50 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 865 8 // //
实施例51 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 865 20 // //
实施例52 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 // // 500 30
实施例53 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 // // 600 25
实施例54 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 // // 700 15
实施例55 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 // // 780 10
实施例56 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 // // 650 5
实施例57 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 // // 650 30
实施例58 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 865 2 650 10
实施例59 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4、CeO 2、LiF 950 20 900 1 700 10
实施例60 Li 2CO 3、Ni 0.48Mn 1.47(OH) 3.9、NH 4H 2PO 4、Cr 2O 3、LiI 950 20 900 1 670 15
实施例61 Li 2CO 3、Ni 0.48Mn 1.47(OH) 3.9、NaOH、SiO 2、TiO 2、LiF 950 20 900 1 640 20
对比例9 Li 2CO 3、Ni 0.5Mn 1.5(OH) 4 950 20 // // 650 20
对比例10 Li 2CO 3、Ni 0.49Mn 1.47(OH) 3.92、NH 4H 2PO 4 950 20 // // // //
表2：各实施例和对比例的正极材料的成分和性能参数
Figure PCTCN2022135597-appb-000001
Figure PCTCN2022135597-appb-000002
表3：各实施例和对比例的电池性能参数
Figure PCTCN2022135597-appb-000003
Figure PCTCN2022135597-appb-000004
结果表明，当尖晶石型含锂锰镍复合氧化物的平均成分中Li含量比例大于1，有M元素改性，且所得活性材料的E值(I 111/I 400)大于或等于2.3且小于或等于3.0时，以该材料作为正极活性材料所制得的电池具有较好的综合性能，具体为具有较好的循环性，较高的存储性能、能量密度及电性能综合系数。
请结合参阅附图1和附图2，图1和图2均是本申请部分实施例和对比例的X射线衍射图谱。具体包括对比例1、实施例2、实施例3、实施例29、实施例42、对比例7的X射线衍射图谱。一并参 阅表2和表3的数据，对比例1的E值过小，使得正极材料的稳定性差，进而导致电池的循环性和存储性能差，且电性能综合系数也变低。通过实施例1-2和对比例1可以看出，当E值在预期范围(2.3-3.0)时，电池的能量密度和存储性能有所提升，但存储性能和综合性能改善不明显；这说明控制E值范围能够提高电池性能，但是由于实施例1-2中锂含量偏低，使得电池的综合性能略低，这说明需综合平衡多个参数，来提高电池的综合性能。或者说控制E值范围能够解决本申请提出的提高正极材料稳定性，提高电池容量的技术问题。再或者说，本申请不限定Li含量比例必须大于1，当Li含量比例不大于1时，也能够实现E值在预定范围内。结合实施例3-4可以看出，在调控E值在预期范围，且Li含量比例大于1时电池的各项性能均有明显改善，提供了综合性能。
通过实施例5-21和对比例3-5可以看出，调控锂锰镍复合氧化物中M、N、Q元素的掺杂也可以调控改善电池的性能，M元素的掺杂能够配合调控E值在预定范围内。
通过实施例22-37和对比例6-7可以看出，通过合理调配Li含量以及M元素含量，能够提高电池的综合性能，具有好的循环性、高的存储性能、较高的能量密度及电性能综合系数。
通过实施例38-58和对比例2可以看出，通过调控锂锰镍复合氧化物的制备工艺也可以调控改善电池的性能，配合调控E值在预定范围内。通过实施例42可以看出，即使高温处理也能够实现E值在预定范围内，只是温度过高，能耗大而已，或者说，即使不是优选工艺，仅调控成分含量也能够实现氧化物性能的调控。
请参阅附图3，附图3是本申请部分实施例和对比例的扣式电池的首圈充电曲线。具体包括对比例1、对比例2、实施例1、实施例4的首圈充电曲线。一并参阅表2和表3的数据，可得通过本申请所提供正极活性材料的4V平台占比R值在合理范围内，使电池具有较好的综合性能。
请结合参阅附图4-图8，图4是本申请实施例3的正极活性材料用扫描电镜测试的形貌图；图5是本申请实施例36的正极活性材料用扫描电镜测试的形貌图；图6是本申请实施例46的正极活性材料用扫描电镜测试的形貌图；图7是本申请实施例47的正极活性材料用扫描电镜测试的形貌图；图8是本申请对比例1的正极活性材料用扫描电镜测试的形貌图。本申请所提供的正极活性材料包括单晶颗粒，相对于同颗粒尺寸的多晶，单晶颗粒表面都是较为稳定的晶面、比表面积小、加工和服役过程开裂暴露不稳定表面的概率更小，有利于减缓表面副反应；相比于同晶粒尺寸的多晶，单晶因为颗粒小而更有利于动力学性能，同样不易开裂。
以上所述仅为本申请的实施方式，并非因此限制本申请的专利范围，凡是利用本申请说明书及附图内容所作的等效结构或等效流程变换，或直接或间接运用在其他相关的技术领域，均同理包括在本申请的专利保护范围内。

Claims (25)

  1. 一种锂锰镍复合氧化物，其中，
    所述锂锰镍复合氧化物的晶型为尖晶石型，所述锂锰镍复合氧化物的X射线衍射谱图中(111)峰的峰强度I 111与(400)峰的峰强度I 400的比值2.1≤I 111/I 400≤3.3，其中(111)峰为衍射角2θ＝18°-19.5°的峰，(400)峰为衍射角2θ＝43.5°-45°的峰。
  2. 根据权利要求1所述的锂锰镍复合氧化物，其中，
    所述锂锰镍复合氧化物的平均化学成分为Li 1+aM xNi 0.5+zMn 1.5-x-zO 4-k，其中，0<a≤0.3，0<x≤0.2，-0.3≤z≤0.3，0≤k≤0.2，M包括Na、Si、P、S、Nb、Mo、Ru、Te、Ce、Ta、W中的一种或多种元素。
  3. 根据权利要求1或2所述的锂锰镍复合氧化物，其中，
    所述锂锰镍复合氧化物的平均化学成分为Li 1+aM xN yNi 0.5+zMn 1.5-x-y-zO 4-k-qQ q，其中，0<a≤0.3，0<x≤0.2，0≤y≤0.3，-0.3≤z≤0.3，0≤k≤0.2，0≤q≤0.5，M包括Na、Si、P、S、Nb、Mo、Ru、Te、Ce、Ta、W中的一种或多种元素，N包括Mg、Al、K、Sc、Ti、V、Cr、Fe、Co、Rb、Sr、Y、Zr、Rh、Sb、La、Sm、Gd、Yb、Lu、Hf中的一种或多种元素，Q包括F、Cl、Br、I中的一种或多种元素。
  4. 根据权利要求2或3所述的锂锰镍复合氧化物，其中，1≤a/x≤20。
  5. 根据权利要求2-4任一项所述的锂锰镍复合氧化物，其中，0.03≤a≤0.15。
  6. 根据权利要求2-5任一项所述的锂锰镍复合氧化物，其中，0.002≤x≤0.1。
  7. 根据权利要求2-6任一项所述的锂锰镍复合氧化物，其中，0<x+y+z≤0.3。
  8. 根据权利要求2-7任一项所述的锂锰镍复合氧化物，其中，2.4≤I 111/I 400≤2.8；2≤a/x≤10；0.05≤a≤0.12；0.01≤x≤0.06；0.005≤y≤0.05；0.01≤z≤0.1；0.01≤x+y+z≤0.1；0.01≤q≤0.1；0≤k≤0.1。
  9. 根据权利要求1-8任一项所述的锂锰镍复合氧化物，其中，
    所述锂锰镍复合氧化物的X射线衍射谱图中在衍射角2θ＝21.5°-24°之间至少存在一个峰，衍射角2θ＝21.5°-24°之间的最强峰与(111)峰的强度的比值0<I (21.5°-24°)/I 111≤3％。
  10. 根据权利要求1-9任一项所述的锂锰镍复合氧化物，其中，
    在以所述锂锰镍复合氧化物为正极材料，以Li为负极材料的电池中，当以0.1C充电倍率的充电条件下，电池在3.5-4.4V区间的充电容量与在3.5-4.95V区间的总充电容量的比值小于或等于15％。
  11. 根据权利要求1-10任一项所述的锂锰镍复合氧化物，其中，所述锂锰镍复合氧化物包括单晶颗粒、类单晶颗粒、二次颗粒中的一种或多种。
  12. 根据权利要求11所述的锂锰镍复合氧化物，其中，单个二次颗粒中所含的晶粒数量1≤n≤8。
  13. 根据权利要求11或12所述的锂锰镍复合氧化物，其中，晶粒外形包括类球形、八面体、八面体削尖去棱的规则外形、棱角圆润的八面体和/或棱角圆润的八面体削尖去棱的多面体规则外形中的任意一种或多种。
  14. 根据权利要求1-13任一项所述的锂锰镍复合氧化物，其中，所述锂锰镍复合氧化物的体积中值粒径2μm≤D V50≤20μm。
  15. 根据权利要求1-14任一项所述的锂锰镍复合氧化物，其中，所述锂锰镍复合氧化物的粉体酸碱度10≤pH≤12。
  16. 根据权利要求1-15任一项所述的锂锰镍复合氧化物，其中，所述锂锰镍复合氧化物的比表面积0<BET≤0.8m 2/g。
  17. 一种正极极片，其中，包括正极材料和正极集流体，所述正极材料包括如权利要求1-16任一项所述的锂锰镍复合氧化物。
  18. 一种电池，其中，包括：正极极片、隔离膜以及负极极片，所述隔离膜处于正极极片与负极极片之间起到隔离的作用，所述正极极片包括如权利要求17所述的正极极片。
  19. 根据权利要求18所述的电池，其中，所述电池还包括电解液，所述电解液的电解液溶剂包括氟代碳酸酯、氟代羧酸酯、砜类、氟代醚中的一种或多种。
  20. 一种用电装置，其中，包括权利要求18或19所述的电池。
  21. 一种锂锰镍复合氧化物的制备方法，其中，包括：
    提供锂锰镍复合氧化物的原料；
    将所述锂锰镍复合氧化物的原料在含氧气的氛围下进行热处理，得到如权利要求1-16任一项所述的锂锰镍复合氧化物。
  22. 根据权利要求21所述的锂锰镍复合氧化物的制备方法，其中，所述将锂锰镍复合氧化物的原料在含氧气的氛围下进行热处理包括：
    将所述锂锰镍复合氧化物的原料升温至T1，保温2-50h，得到锂锰镍复合氧化物中间体；其中，850℃≤T1≤1100℃。
  23. 根据权利要求22所述的锂锰镍复合氧化物的制备方法，其中，还包括：
    将所述锂锰镍复合氧化物中间体升温至T2，保温0.5-20h，得到锂锰镍复合氧化物预制体；其中T1-200℃≤T2≤T1且T2≥800℃。
  24. 根据权利要求23所述的锂锰镍复合氧化物的制备方法，其中，还包括：
    将所述锂锰镍复合氧化物预制体升温至T3，保温5-30h，得到所述锂锰镍复合氧化物；其中，500℃≤T3≤800℃。
  25. 根据权利要求21-24任一项所述的锂锰镍复合氧化物的制备方法，其中，所述提供锂锰镍复合氧化物的原料包括：
    按照目标成分Li 1+aM xNi 0.5+zMn 1.5-x-zO 4-k提供化学计量比的Li 2CO 3、Ni 0.5+zMn 1.5-x-z(OH) 4-2x、M bO c粉体，混合均匀，得到所述锂锰镍复合氧化物的原料；
    其中，0<a≤0.3，0＜x≤0.2，-0.3≤z≤0.3，0≤k≤0.2，M包括钠(Na)、硅(Si)、磷(P)、硫(S)、铌(Nb)、钼(Mo)、钌(Ru)、碲(Te)、铈(Ce)、钽(Ta)、钨(W)中的一种或多种元素。
PCT/CN2022/135597 2022-11-30 2022-11-30 锂锰镍复合氧化物及其制备方法、极片、电池、用电装置 Ceased WO2024113250A1 (zh)

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