A composite-coated lithium transition metal oxide material, and a method for preparing and using the same

Abstract

The application discloses a kind of composite coated lithium transition metal oxide materials and preparation method and application thereof, belong to battery material technical field.The composite coated lithium transition metal oxide material includes lithium transition metal oxide material and the composite of coating on the surface of lithium transition metal oxide material;The chemical formula of lithium transition metal oxide material is Li a M 1‑b M′ b O2, the chemical formula of composite is ABC3;When B and M have same element, the chemical state of same element in composite is different from the chemical state in lithium transition metal oxide material.The composite coated lithium transition metal oxide material has lower impedance, better ion conduction, lower gas production, better cycle performance and safety performance at high voltage, which is beneficial to improve the electrochemical performance of lithium ion battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery materials, in particular to a composite-coated lithium transition metal oxide material and a preparation method and application thereof. BACKGROUND

[0002] Lithium ion layered batteries have high capacity, discharge platform and compaction density, and are one of the most studied and widely used commercial lithium ion battery cathode materials. The lithium ion cathode material is directly in contact with the electrolyte, which is easily corroded by the electrolyte, and the original layered structure is destroyed, and the electrolyte is oxidized and decomposed, resulting in gas production, which ultimately leads to rapid capacity decay of the battery, and safety problems such as battery bulging, burning and explosion.

[0003] Coating other materials on the surface of lithium transition metal oxide materials can effectively reduce the contact area between the cathode material and the electrolyte, reduce the dissolution amount of Co, Mn, Ni and other transition metals, and improve the structural stability and cycle performance.

[0004] Common coating materials use metal oxides such as ZnO, Al2O3, TiO2, etc. Such materials have stable structure and will not react with the electrolyte, thereby protecting the cathode material. However, most oxides are electronically insulating, and oxide coating will reduce the capacity. Some coating materials use metal phosphates such as AlPO4, LiPO3, LiMgPO4, etc. Such materials have improved capacity retention rate when coating the cathode material, but the phosphates cannot eliminate the corrosion of the electrolyte on the surface of the cathode at high voltage, and the protection capability at high voltage is limited.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] The present application aims to provide a composite-coated lithium transition metal oxide material and a preparation method and application thereof to solve or improve the above technical problems.

[0007] The present application can be achieved as follows:

[0008] In a first aspect, the present application provides a composite-coated lithium transition metal oxide material, which comprises a lithium transition metal oxide material and a composite coated on the surface of the lithium transition metal oxide material.

[0009] The chemical formula of the lithium transition metal oxide material is Li a M 1-b M' bO2, wherein 0.98≤a≤1.03, 0<b≤0.1, the M-type element includes at least one of Ni, Co and Mn; the M'-type element includes at least one of Ba, La, Ti, Zr, V, Nb, Cu, Mg, B, S, Sr, Al, Sc, Y, Ga, Zn, W, Mo, Si, Sb and Ca;

[0010] The chemical formula of the complex is ABC3, wherein the A-type element includes at least one of Pb, Na, Sn, Sr, K, Ca, Ba, Sr, Ln, Pr, Sm, Gd, Bi, Cs, Ca and La; the B-type element includes at least one of Ti, Y, Zn, Fe, Ta, Mn, Co, Ni, Mo, Nb, W, Pb and Al; and the C-type element includes at least one of F, Cl, Br, I and O.

[0011] When the B-type element in the complex is the same as the M element in the lithium transition metal oxide material, the chemical state of the same element in the complex is different from the chemical state in the lithium transition metal oxide material.

[0012] In an optional embodiment, the complex-coated lithium transition metal oxide material has at least one of the following characteristics:

[0013] Characteristic 1: the lithium transition metal oxide material is in a layered structure.

[0014] Characteristic 2: the mass of the complex is no more than 5% of the mass of the complex-coated lithium transition metal oxide material.

[0015] In an optional embodiment, the mass of the complex is no more than 3% of the mass of the complex-coated lithium transition metal oxide material.

[0016] In an optional embodiment, the A-type element is a rare earth or an alkaline earth metal, the B-type element is a transition metal, and the element radius of the B-type element is smaller than the element radius of the A-type element.

[0017] In an optional embodiment, the C-type element includes at least one of F, Cl and O; more preferably, the C-type element is O.

[0018] In an optional embodiment, the complex is an ABO3 complex oxide, wherein the cation corresponding to the A-type element is in a 12-coordinated structure and located in a cavity composed of octahedrons; and the transition metal ion corresponding to the B-type element forms an octahedral coordination with six oxygen ions.

[0019] In an optional embodiment, in the ABO3 complex oxide, the B-type element forms a regular octahedral symmetry structure with O, the B-type element is located at the center of the octahedron to form a cubic symmetry structure; and the A-type element is distributed at the center of the octahedron to form a cube.

[0020] In an optional embodiment, the ABO3 composite oxide is selected from LaMnO3, BiFeO3, CsPbI3, CaTiO3, BaTiO3, SnTiO3, PbTiO3, KTaO3, LaFeO3, LaNiO3, SrTiO3, or LaAlO3, etc.

[0021] In an optional embodiment, the A-type element in the composite is composed of A' and A", the B-type element is composed of B' and B", and the chemical formula of the composite is A'A"B'B"O6; wherein A' and A" are different elements and B' and B" are the same element, A' is a lanthanide element and the radius of A" is greater than that of A'; B' and B" are both variable valence elements.

[0022] In an optional embodiment, A'A"B'B"O6 is selected from YSmFe2O6, YPrFe2O6, YPrMn2O6, YPrCo2O6, or YLaMn2O6, etc.

[0023] In an optional embodiment, the A-type element in the composite is composed of A' and A", the B-type element is composed of B' and B", and the chemical formula of the composite is A'A"B'B"O6; wherein B' and B" are different elements and A' and A" are the same element, A' and A" are both alkaline earth metal elements, B' and B" are both transition metal elements and the valence of B" is higher than that of B'.

[0024] In an optional embodiment, A'A"B'B"O6 is selected from Ca2FeWO6, Ca2NiMoO6, Ba2NiNbO6, or Sr2NiWO6, etc.

[0025] In a second aspect, the present application provides a preparation method of the composite-coated lithium transition metal oxide material according to any one of the preceding embodiments, comprising the following steps: mixing the lithium transition metal oxide primary powder prepared from a lithium source, an M source and part of an M' source, the ABC3 composite powder prepared from an A source, a B source and a C source, and the remaining M' source, and then sintering.

[0026] In an optional embodiment, the lithium transition metal oxide primary powder, the ABC3 composite powder and the remaining M' source are mixed under the condition that the rotation speed is 500 r / min-1500 r / min.

[0027] In an optional embodiment, the mixing time of the lithium transition metal oxide primary powder, the ABC3 composite powder and the remaining M' source is 10 min-60 min.

[0028] In an optional embodiment, the sintering temperature is 300℃-1050℃, preferably 500℃-950℃.

[0029] In an optional embodiment, the sintering time is 1h-10h, preferably 2h-8h.

[0030] In an optional embodiment, the preparation of the lithium transition metal oxide primary powder comprises: mixing a lithium source, an M source and part of an M' source, and then calcining.

[0031] In an optional embodiment, the lithium source comprises at least one of lithium carbonate and lithium hydroxide.

[0032] In an optional embodiment, the M source comprises at least one of an oxide of the M-type element and a hydroxide of the M-type element.

[0033] In an optional embodiment, the M source comprises at least one of tricobalt tetroxide, cobalt oxyhydroxide, cobalt carbonate, cobalt hydroxide, nickel cobalt manganese oxide, nickel cobalt manganese hydroxide, manganese hydroxide, nickel hydroxide, nickel oxide and manganese oxide.

[0034] In an optional embodiment, the M' source comprises at least one of an oxide of the M'-type element, a hydroxide of the M'-type element, an acetate of the M'-type element and a carbonate of the M'-type element.

[0035] In an optional embodiment, the calcining temperature after mixing the lithium source, the M source and part of the M' source is 650℃-1200℃, preferably 850℃-1080℃.

[0036] In an optional embodiment, the calcining time after mixing the lithium source, the M source and part of the M' source is 5h-15h, preferably 6h-13h.

[0037] In an optional embodiment, the particle size of the lithium transition metal oxide primary powder is 2μm-25μm.

[0038] In an optional embodiment, the preparation of the ABC3 composite powder comprises: mixing an A source, a B source and a C source, and then sintering.

[0039] In an optional embodiment, the A source comprises at least one of an oxide of the A-type element, a hydroxide of the A-type element, an acetate of the A-type element and a carbonate of the A-type element.

[0040] In an optional embodiment, the B source comprises at least one of an oxide of the B-type element, a hydroxide of the B-type element, an acetate of the B-type element and a carbonate of the B-type element.

[0041] In an optional embodiment, the sintering temperature after mixing the A source, the B source and the C source is 700℃-1350℃, preferably 800℃-1250℃.

[0042] In an optional embodiment, the sintering time after mixing source A, source B and source C is 3h to 12h, preferably 5h to 10h.

[0043] In an optional embodiment, the particle size of the ABC3 composite powder is 1 nm to 20 μm, preferably 5 nm to 10 μm.

[0044] Thirdly, the present invention provides a positive electrode sheet, wherein the active material in the positive electrode sheet includes a lithium transition metal oxide material coated with a composite of any of the foregoing embodiments.

[0045] Fourthly, the present invention provides a battery comprising the positive electrode sheet of the aforementioned embodiments.

[0046] The beneficial effects of this invention include:

[0047] The lithium transition metal oxide material coated with a composite provided by this invention improves the phase interface by combining the composite with layered materials, alleviating the gas generation problem of the cathode material under high voltage. This results in better high-voltage stability of the cathode material during cycling, thereby enabling the lithium-ion battery to achieve high-voltage cycle capacity retention and improving the performance of the lithium-ion battery. Furthermore, by using the ABC3 composite coating, the lithium-ion conductivity on the surface of the lithium transition metal oxide material is improved, and the corrosion of the cathode surface by the electrolyte is reduced. The resulting lithium transition metal oxide material exhibits good cycle performance, low impedance, and low gas generation. Attached Figure Description

[0048] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 This is a structural diagram of the strontium tungsten nickel oxide in Example 4 of the present invention;

[0050] Figure 2 This is a SEM image of the pulverized strontium-tungsten-nickel oxide powder in Example 4 of the present invention;

[0051] Figure 3 This is a SEM cross-sectional view of the lithium cobalt oxide cathode material coated with strontium titanate oxide in Example 5 of the present invention;

[0052] Figure 4 This is a SEM image of the lithium cobalt oxide cathode material coated with strontium titanate oxide in Example 5 of the present invention. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below. For those not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0054] The composite-coated lithium transition metal oxide material provided by the present invention, its preparation method, and applications will be specifically described below.

[0055] The composite-coated lithium transition metal oxide material proposed by the present invention includes a lithium transition metal oxide material and a composite coated on the surface of the lithium transition metal oxide material.

[0056] The chemical formula of the above lithium transition metal oxide material is Li a M 1-b M′ b O2, where 0.98 ≤ a ≤ 1.03, 0 < b ≤ 0.1, the M-type elements include at least one of Ni, Co, and Mn; the M′-type elements include at least one of Ba, La, Ti, Zr, V, Nb, Cu, Mg, B, S, Sr, Al, Sc, Y, Ga, Zn, W, Mo, Si, Sb, and Ca;

[0057] The chemical formula of the composite is ABC3, where the A-type elements include at least one of Pb, Na, Sn, Sr, K, Ca, Ba, Sr, Ln, Pr, Sm, Gd, Bi, Cs, Ca, and La; the B-type elements include at least one of Ti, Y, Zn, Fe, Ta, Mn, Co, Ni, Mo, Nb, W, Pb, and Al; the C-type elements include at least one of F, Cl, Br, I, and O. It should be noted that "B" in the above ABC3 does not refer to the boron element, and "C" does not refer to the carbon element.

[0058] When the B-type elements in the composite are the same as the M-type elements in the lithium transition metal oxide material, the chemical state of the same element in the composite is different from that in the lithium transition metal oxide material.

[0059] The above composite-coated lithium transition metal oxide material proposed by the present invention has a lower impedance, better ion conduction, lower gas generation, better cycle performance and safety performance at high voltages, which is beneficial to improving the electrochemical performance of lithium-ion batteries.

[0060] In some embodiments, the mass of the composite does not exceed 5% of the mass of the lithium transition metal oxide material coated by the composite, for example, it can be 5%, 4%, 3%, 2%, or 1%, or other values ​​not exceeding 5%. In some alternative embodiments, the mass of the composite does not exceed 3% of the mass of the lithium transition metal oxide material coated by the composite.

[0061] In some implementations, the A-type elements are rare earth or alkaline earth metals, the B-type elements are transition metals, and the radius of the B-type elements is smaller than that of the A-type elements.

[0062] In some embodiments, class C elements include at least one of F, Cl, and O. In some more typical embodiments, class C elements are O.

[0063] For example, when element C is O, the complex is an ABO3 complex oxide. In some embodiments, the cation corresponding to element A in the ABO3 complex oxide has a 12-coordinate structure and is located within a cavity formed by octahedrons; the transition metal ion corresponding to element B forms an octahedral coordination with six oxygen ions. Further, in the above-mentioned ABO3 complex oxide, element B forms a regular octahedral symmetric structure with O, and element B is located at the center of the octahedron, forming a cubic symmetric structure; element A is distributed at the center of the octahedrons to form a cube, thereby forming a stable crystal structure.

[0064] In the ABO3 structure, at lower temperatures, surface-adsorbed oxygen plays a major role in oxidation, and this oxygen adsorption capacity is determined by the metal at the B site. At higher temperatures, lattice oxygen plays a role. The amount and activity of lattice oxygen can be adjusted by changing the A-type and B-type elements. In addition, replacing the +3-valent A and B atoms in the lattice with +2 or +4-valent atoms can also generate lattice defects or lattice oxygen, thereby improving ionic conductivity and material activity.

[0065] In some of the listed embodiments, the ABO3 composite oxide may be selected from LaMnO3, BiFeO3, CsPbI3, CaTiO3, BaTiO3, SnTiO3, PbTiO3, KTaO3, LaFeO3, LaNiO3, SrTiO3, or LaAlO3, etc.

[0066] In this invention, the number of combinations of A-type elements and B-type elements is not limited to a single composite structure, but can also be a double composite structure, a triple composite structure, a quadruple composite structure, or a multi-composite structure. Specifically, A-type elements may include A', A”, A”', etc., and B-type elements may include B', B”, B”', etc., wherein the elements belonging to A-type elements such as A', A”, and A”' can be the same or different, and these elements belonging to A-type elements are all located at the same A position in the structure; similarly, the elements belonging to B-type elements such as B', B”, and B”' can be the same or different, and these elements belonging to B-type elements are all located at the same B position in the structure. This can be understood as follows: a single composite structure refers to a composite material of A'B'C3, a double composite structure is A'A”B'B”C6, a triple composite structure is A'A”A”'B'B”B”'C9, and so on. For example, the ABC3 structure may include A'A”B'B”C6, A'2B'B”C6, A'A”B'2C6, or A'2A”B'2B”C9, etc., as long as all A:all B:C in the structural formula = 1:1:3, it falls within the protection scope of the ABC3 structure of this invention. Furthermore, a slight deviation in the A:B = 1 ratio, with a deviation value < 5.0%, also falls within the protection scope of the ABC3 structure of this invention.

[0067] In some embodiments, the A-type elements in the complex are composed of A' and A" and the B-type elements are composed of B' and B", and the chemical formula of the complex is A'A"B'B"O6; wherein A' and A" are different elements and B' and B" are the same element, A' is a lanthanide element and the radius of element A" is larger than the radius of element A'; B' and B" are both elements with variable valence states (e.g., +2 or +4). For example, A'A"B'B"O6 may be selected, but not exclusively, from YSmFe2O6, YPrFe2O6, YPrMn2O6, YPrCo2O6, or YLaMn2O6.

[0068] In some other embodiments, the A-type elements in the complex are composed of A' and A" and the B-type elements are composed of B' and B", and the chemical formula of the complex is A'A"B'B"O6; wherein B' and B" are different elements and A' and A" are the same element, A' and A" are both alkaline earth metal elements, B' and B" are both transition metal elements, and the valence state of element B" is higher than that of element B'. For example, A'A"B'B"O6 can be selected from Ca2FeWO6, Ca2NiMoO6, Ba2NiNbO6 or Sr2NiWO6 by way of example but not by way of limitation.

[0069] Furthermore, when partial substitution occurs at the positions of class B elements, such as Sr2FeMo 0.65 Ni 0.35 O6 or Sr2FeMo 0.35 Ni 0.65O6 and others fall within the scope of protection of this invention. Similarly, when partial substitution occurs at the position of a class A element, such as La... 0.35 Y 0.65 SmFe2O6 or La 0.65 Y 0.35 SmFe2O6 and other substances also fall within the scope of protection of this invention.

[0070] Taking the ABC3 composite as an example, the lithium transition metal oxide material coated by this composite can form a transition layer structure on the shallow surface during cycling. There are oxygen ion vacancies in the ABO3 composite. The increase in the concentration of intrinsic oxygen vacancies through doping substitution makes the ABO3 structure a fast ion conductor. It forms a continuous ion transport channel, accelerates ion conduction, and thus can significantly increase the diffusion path of lithium ions and improve the lithium ion conduction of the cathode material.

[0071] Furthermore, the A and B sites in the ABO3 complex can be replaced by other similar metal ions while maintaining its crystal structure. Its physical and chemical properties can vary depending on the composition of A and B, exhibiting strong ionic conductivity, ferromagnetism, or superconductivity, among other properties. Stable ABO3 complex structures can be tetragonal, orthorhombic, hexagonal, or trigonal, with high oxygen vacancy concentrations causing structural distortion. Because oxygen readily undergoes charge compensation in the high delithiation state of the cathode material, leading to oxygen release, ABO3 structures such as tetragonal, orthorhombic, hexagonal, and trigonal contain numerous octahedral holes that can adsorb gas, reducing gas release and production, thus improving safety and cycle performance.

[0072] Building upon the above, the composite-coated lithium transition metal oxide material provided by this invention improves the phase interface through the combination of the composite and the layered material, alleviating the gas generation problem of the cathode material under high voltage. This results in better high-voltage stability of the cathode material during cycling, thereby enabling the lithium-ion battery to achieve high-voltage cycle capacity retention and improving the performance of the lithium-ion battery. Furthermore, by using the ABC3 composite coating, the lithium-ion conductivity on the surface of the lithium transition metal oxide material is improved, and the corrosion of the cathode surface by the electrolyte is reduced. The resulting lithium transition metal oxide material exhibits good cycle performance, low impedance, and low gas generation at 4.35V, 4.5V, and 4.6V.

[0073] Accordingly, the present invention provides a method for preparing the lithium transition metal oxide material coated by the above-mentioned composite, comprising the following steps: mixing and sintering a primary lithium transition metal oxide powder prepared from a lithium source, an M source and part of an M′ source, an ABC3 composite powder prepared from an A source, a B source and a C source, and the remaining M′ source.

[0074] For ease of distinction, "partial M′ source" is defined as the first M′ source, and "remaining M′ source" as the second M′ source. The total amount of the first M′ source and the second M′ source is the total amount of M′ source in the lithium transition metal oxide material coated by the composite. The first M′ source and the second M′ source can be the same or different. The amount of the first M′ source is higher than that of the second M′ source. The first M′ source mainly functions as a dopant, acting on the bulk phase to improve the structural stability of the material, which is beneficial for improving the cycling performance and ionic conductivity. The second M′ source mainly functions as a coating, improving the surface stability of the material and mitigating surface microcracks.

[0075] In some embodiments, the primary lithium transition metal oxide powder can be prepared by a solid-state method, which may include the following steps: mixing a lithium source, an M source and a portion of an M′ source, followed by calcination and crushing.

[0076] Lithium sources may include, by way of example but not by way of limitation, at least one of lithium carbonate and lithium hydroxide.

[0077] M-sources include at least one of oxides and hydroxides of M-type elements. For example, M-sources may, by way of example but not limitation, include at least one of cobalt tetroxide, cobalt hydroxyl oxide, cobalt carbonate, cobalt hydroxide, nickel cobalt manganese oxide, nickel cobalt manganese hydroxide, manganese hydroxide, nickel hydroxide, nickel oxide, and manganese oxide.

[0078] M′ sources may, by way of example but not limitation, include at least one of oxides of M′-type elements, hydroxides of M′-type elements, acetates of M′-type elements, and carbonates of M′-type elements. Basic carbonates are also included in the category of carbonates.

[0079] The calcination temperature of the mixture of the lithium source, M source, and first M′ source can be between 650℃ and 1200℃, such as 650℃, 700℃, 750℃, 800℃, 850℃, 900℃, 950℃, 1000℃, 1050℃, 1100℃, 1150℃, or 1200℃, or other values ​​within the range of 650℃ to 1200℃. In some embodiments, the calcination temperature of the mixture of the lithium source, M source, and first M′ source is between 850℃ and 1080℃.

[0080] The calcination time after mixing the lithium source, M source, and the first M′ source can be 5h to 15h, such as 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, or 15h, or other values ​​within the range of 5h to 15h. In some embodiments, the calcination time after mixing the lithium source, M source, and the first M′ source is 6h to 13h.

[0081] In some embodiments, the particle size of the primary lithium transition metal oxide powder can be 2μm to 25μm, such as 2μm, 5μm, 10μm, 15μm, 20μm or 25μm, or other values ​​within the range of 2μm to 25μm.

[0082] ABC3 composite powder can be prepared by solid-state sintering, or by salt decomposition, co-precipitation, sol-gel, hydrothermal, reverse emulsion or template methods.

[0083] When ABC3 composite powder is prepared by solid-state sintering, it may include the following steps: mixing source A, source B and source C and then sintering.

[0084] The A source may, by way of example but not by way of limitation, include at least one of an oxide of an A-type element, a hydroxide of an A-type element, an acetate of an A-type element, and a carbonate of an A-type element.

[0085] Source B may, by way of example but not limitation, include at least one of oxides of type B elements, hydroxides of type B elements, acetates of type B elements, and carbonates of type B elements.

[0086] When the element of class C is 0, it can be directly provided by source A and / or source B.

[0087] The sintering temperature of the mixture of sources A, B, and C can be between 700℃ and 1350℃, such as 700℃, 800℃, 900℃, 1000℃, 1100℃, 1200℃, 1300℃, or 1350℃, or other values ​​within the range of 700℃ to 1350℃. In some embodiments, the sintering temperature of the mixture of sources A, B, and C is between 800℃ and 1250℃.

[0088] The sintering time for the mixture of sources A, B, and C can be 3h to 12h, such as 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, or 12h, or other values ​​within the range of 3h to 12h. In some embodiments, the sintering time for the mixture of sources A, B, and C is 5h to 10h.

[0089] In some embodiments, the particle size of the ABC3 composite powder can be 1 nm to 20 μm, such as 1 nm, 10 nm, 100 nm, 500 nm, 1 μm, 5 μm, 10 μm, 15 μm, or 20 μm, or other values ​​within the range of 1 nm to 20 μm. In some embodiments, the particle size of the ABC3 composite powder is 5 nm to 10 μm.

[0090] In some embodiments, the lithium transition metal oxide primary powder, the ABC3 composite powder, and the second M′ source can be mixed at a rotation speed of 500 r / min to 1500 r / min (e.g., 500 r / min, 1000 r / min, or 1500 r / min).

[0091] The mixing time of the primary lithium transition metal oxide powder, the ABC3 composite powder, and the second M′ source can be 10 min to 60 min, such as 10 min, 20 min, 30 min, 40 min, 50 min, or 60 min.

[0092] The sintering temperature of the primary lithium transition metal oxide powder, the ABC3 composite powder, and the second M′ source can be between 300℃ and 1050℃, such as 300℃, 400℃, 500℃, 600℃, 700℃, 800℃, 900℃, 1000℃, or 1050℃, or other values ​​within the range of 300℃ to 1050℃. In some embodiments, the sintering temperature of the primary lithium transition metal oxide powder, the ABC3 composite powder, and the second M′ source is between 500℃ and 950℃.

[0093] The sintering time for the primary lithium transition metal oxide powder, the ABC3 composite powder, and the second M′ source can be from 1 h to 10 h, such as 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, or 10 h, or other values ​​within the range of 1 h to 10 h. In some embodiments, the sintering time for the primary lithium transition metal oxide powder, the ABC3 composite powder, and the second M′ source is 2 h to 8 h.

[0094] After mixing and sintering the primary lithium transition metal oxide powder, the ABC3 composite powder, and the second M′ source, a light dissociation step can be further performed. Light dissociation methods can include passing the mixture through a vibrating screen, mechanical mill, or air jet mill.

[0095] In addition, the present invention also provides a positive electrode sheet, wherein the active material in the positive electrode sheet includes lithium transition metal oxide material coated with the above-mentioned composite.

[0096] The present invention also provides a battery cell comprising the above-mentioned positive electrode sheet.

[0097] For example, the aforementioned battery cells can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft.

[0098] The present invention also provides a battery comprising the above-described battery cells.

[0099] The present invention also provides an electrical device comprising the aforementioned battery cell and / or battery. As examples, the electrical device may include, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys may include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., while spacecraft may include airplanes, rockets, space shuttles, and spacecraft, etc.

[0100] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0101] Example 1

[0102] This embodiment provides a composite-coated lithium transition metal oxide material (i.e., a perovskite oxide-coated lithium cobalt oxide cathode material), and the preparation method of this composite-coated lithium transition metal oxide material includes:

[0103] Step (1): Preparation of lithium cobalt oxide cathode material: Lithium carbonate, cobalt tetroxide, titanium oxide and aluminum oxide are mixed evenly in a molar ratio of Li:Co:Al:Ti = 1.05:1.00:0.02:0.001, sintered at 1020℃ for 10h, and then crushed to obtain primary lithium cobalt oxide powder with a particle size of 18μm.

[0104] Step (2): Preparation of calcium titanium oxide: Calcium carbonate and titanium dioxide are uniformly mixed, wherein the molar ratio of calcium to titanium is 1.00:1.00, sintered at 500℃ for 5h, and then pulverized to obtain calcium titanium oxide with a particle size of 30nm.

[0105] Step (3): The calcium titanium oxide, alumina and lithium cobalt oxide primary powder are uniformly mixed, wherein the calcium titanium oxide accounts for 0.2% of the mass of the lithium cobalt oxide primary powder and the alumina accounts for 0.2% of the mass of the lithium cobalt oxide primary powder. The mixing equipment speed is 1300 r / min and the time is 20 min. After the mixing is completed, it is sintered in a box furnace at 850℃ and held for 7 h to obtain block calcium titanium oxide coated lithium cobalt oxide cathode material. After crushing, it is passed through a 400 mesh sieve to obtain nano calcium titanium oxide coated lithium cobalt oxide cathode material.

[0106] Example 2

[0107] This embodiment provides a composite-coated lithium transition metal oxide material (i.e., lanthanum yttrium manganese oxide-coated lithium cobalt oxide cathode material), and the preparation method of this composite-coated lithium transition metal oxide material includes:

[0108] Step (1): Preparation of lithium cobalt oxide cathode material: Lithium carbonate, cobalt hydroxide, magnesium oxide and aluminum oxide are mixed evenly in a molar ratio of Li:Co:Al:Mg = 1.05:1.00:0.02:0.002, sintered at 1050℃ for 10h, and then crushed to obtain primary lithium cobalt oxide powder with a particle size of 5.3μm.

[0109] Step (2): Preparation of lanthanum yttrium manganese oxide: Lanthanum carbonate, yttrium oxide and manganese dioxide are uniformly mixed, wherein the molar ratio of lanthanum:yttrium:manganese is 1.00:1.00:2.00. The mixture is sintered at 700℃ for 5 hours and then pulverized to obtain lanthanum yttrium manganese oxide with a particle size of 40 nm.

[0110] Step (3): Lanthanum yttrium manganese oxide, alumina and lithium cobalt oxide primary powder are uniformly mixed, wherein lanthanum yttrium manganese oxide accounts for 0.4% of the mass of lithium cobalt oxide primary powder and alumina accounts for 0.12% of the mass of lithium cobalt oxide primary powder. The mixing equipment speed is 1300 r / min and the time is 20 min. After the mixing is completed, it is sintered in a box furnace at 850℃ and held for 7 h to obtain blocky lanthanum yttrium manganese oxide coated lithium cobalt oxide cathode material. After crushing, it is sieved through a 500 mesh to obtain nano lanthanum yttrium manganese oxide coated lithium cobalt oxide cathode material.

[0111] Example 3

[0112] This embodiment provides a composite-coated lithium transition metal oxide material (i.e., a ternary cathode material modified with lanthanum aluminate oxide coating), and the preparation method of this composite-coated lithium transition metal oxide material includes:

[0113] Step (1): Preparation of ternary cathode material: Lithium carbonate, nickel cobalt manganese hydroxide, titanium oxide and aluminum oxide are uniformly mixed in the proportion of Li:Me:Al:Ti = 1.05:1.00:0.02:0.001 (Me is NCM622), sintered at 900℃ for 8h, and then crushed to obtain ternary cathode material primary powder with a particle size of 4.3μm.

[0114] Step (2): Preparation of lanthanum aluminate oxide: Aluminum carbonate and lanthanum oxide are mixed evenly, wherein the molar ratio of aluminum to lanthanum is 1.00:0.98. The mixture is sintered at 700℃ for 5 hours and then pulverized to obtain lanthanum aluminate oxide with a particle size of 50 nm.

[0115] Step (3): Lanthanum aluminate oxide, alumina and ternary cathode material primary powder are uniformly mixed, wherein lanthanum aluminate oxide accounts for 0.4% of the mass of ternary cathode material primary powder and alumina accounts for 0.18% of the mass of ternary cathode material primary powder. The mixing equipment speed is 1300 r / min and the time is 20 min. After the mixing is completed, it is sintered in a box furnace at 650℃ and held for 8 h to obtain blocky lanthanum aluminate oxide coated ternary cathode material. After crushing, it is sieved through a 300 mesh sieve to obtain lanthanum aluminate oxide coated ternary cathode material.

[0116] Example 4

[0117] This embodiment provides a composite-coated lithium transition metal oxide material (i.e., a strontium-tungsten-nickel oxide-coated modified ternary cathode material), and the preparation method of this composite-coated lithium transition metal oxide material includes:

[0118] Step (1): Preparation of ternary cathode material: Lithium carbonate, nickel cobalt manganese hydroxide, titanium oxide and aluminum oxide are uniformly mixed in the amount of Li:Me:Al:Ti=1.05:1.00:0.02:0.001 (Me is NCM622), sintered at 900℃ for 8h, and then crushed to obtain ternary cathode material primary powder with a particle size of 4.5μm.

[0119] Step (2): Preparation of strontium tungsten nickel oxide: Strontium oxide, nickel oxide and tungsten oxide are mixed evenly, wherein the molar ratio of strontium:nickel:tungsten is 2.00:1.00:1.00, sintered at 720℃ for 5h, and then pulverized to obtain strontium tungsten nickel oxide with a particle size of 50nm.

[0120] In this step, the structural diagram of strontium tungsten nickel oxide is as follows: Figure 1 As shown, the SEM image of the pulverized strontium-tungsten-nickel oxide powder is as follows: Figure 2 As shown.

[0121] Step (3): Strontium tungsten nickel oxide is uniformly mixed with the primary powder of ternary cathode material and alumina, wherein the strontium tungsten nickel oxide accounts for 0.4% of the mass of the primary powder of ternary cathode material and the alumina accounts for 0.18% of the mass of the primary powder of ternary cathode material. The mixing equipment speed is 1300 r / min and the time is 20 min. After the mixing is completed, it is sintered in a box furnace at 650℃ and held for 8 h to obtain blocky strontium tungsten nickel oxide coated ternary cathode material. After crushing, it is sieved through a 300-mesh sieve to obtain strontium tungsten nickel oxide coated ternary cathode material.

[0122] Example 5

[0123] This embodiment provides a composite-coated lithium transition metal oxide material (i.e., strontium titanate oxide-coated lithium cobalt oxide cathode material), and the preparation method of this composite-coated lithium transition metal oxide material includes:

[0124] Step (1): Preparation of lithium cobalt oxide cathode material: Lithium carbonate, cobalt tetroxide, titanium oxide and aluminum oxide are mixed evenly in a molar ratio of Li:Co:Al:Ti = 1.05:1.00:0.025:0.0015, sintered at 1020℃ for 10h, and then crushed to obtain primary lithium cobalt oxide powder with a particle size of 18.6μm.

[0125] Step (2): Preparation of strontium titanate oxide: Strontium carbonate and titanium dioxide are uniformly mixed, wherein the molar ratio of strontium to titanium is 1.00:1.00, sintered at 750℃ for 5h, and then pulverized to obtain strontium titanate oxide with a particle size of 10nm.

[0126] Step (3): Strontium titanate oxide is uniformly mixed with lithium cobalt oxide primary powder and alumina, wherein strontium titanate oxide accounts for 0.3% of the mass of lithium cobalt oxide primary powder and alumina accounts for 0.12% of the mass of lithium cobalt oxide primary powder. The mixing equipment speed is 1300 r / min and the time is 20 min. After the mixing is completed, it is sintered in a box furnace at 850℃ and held for 7 h to obtain blocky strontium titanate oxide coated lithium cobalt oxide cathode material. After crushing, it is passed through a 400 mesh sieve to obtain nano strontium titanate oxide coated lithium cobalt oxide cathode material.

[0127] The SEM cross-sectional image of the above strontium titanate oxide-coated lithium cobalt oxide cathode material is shown below. Figure 3 As shown, by Figure 3 It can be seen that there are obvious signs of coating on the surface of the lithium cobalt oxide cathode material; the SEM image of the lithium cobalt oxide cathode material coated with the above-mentioned strontium titanate oxide is shown in Figure 1. Figure 4 As shown, by Figure 4 It can be seen that the surface particulate matter shows obvious signs of coating.

[0128] Example 6

[0129] This embodiment adopts a method that is roughly the same as that in embodiment 1, except that M′ (titanium oxide and aluminum oxide) in step (1) is replaced with magnesium oxide, aluminum oxide and lanthanum oxide, wherein the molar ratio of magnesium oxide, aluminum oxide and lanthanum oxide is 3:10:1.

[0130] Example 7

[0131] This embodiment uses a method that is largely the same as that in Embodiment 1, except that the ABC3 complex (calcium titanium oxide) in step (2) is replaced with lanthanum nickelate (LaNiO3).

[0132] Example 8

[0133] This embodiment uses a method that is largely the same as that in Embodiment 1, except that the ABC3 complex (calcium titanium oxide) in step (2) is replaced with calcium nickel molybdate (Ca2NiMoO6).

[0134] Example 9

[0135] This embodiment uses a method that is largely the same as that in Embodiment 1, except that the ABC3 complex (calcium titanate) in step (2) is replaced with yttrium barium copper (Y2BaCu3O9).

[0136] Example 10

[0137] This embodiment uses a method largely the same as that in Embodiment 4, the difference being that the ABC3 complex (strontium tungsten nickel oxide) in step (2) is partially substituted with B, that is, the strontium tungsten nickel oxide is replaced with nickel molybdenum iron strontium oxide (Sr2FeMo). 0.65 Ni 0.35 O6);

[0138] Example 11

[0139] This embodiment uses roughly the same method as Embodiment 4, the difference being that the ABC3 complex in step (2) is replaced with La. 0.35 Y 0.65 SmFe2O6.

[0140] Comparative Example 1

[0141] This comparative example provides a composite-coated lithium transition metal oxide material (i.e., a perovskite oxide-coated lithium cobalt oxide cathode material), and the preparation method of this composite-coated lithium transition metal oxide material includes:

[0142] Step (1): Preparation of lithium cobalt oxide cathode material: Lithium carbonate and cobalt tetroxide are mixed evenly at a Li:Co molar ratio of 1.05:1.00, sintered at 1020℃ for 10h, and then crushed to obtain primary lithium cobalt oxide powder with a particle size of 18.5μm.

[0143] Step (2): Same as in Example 1.

[0144] Step (3): Same as in Example 1.

[0145] That is, the difference between this comparative example and Example 1 is that in step (1), the corresponding M′ was not added.

[0146] Comparative Example 2

[0147] The difference between this comparative example and Example 1 is that step (2) is omitted. That is, it is prepared only by steps (1) and (3).

[0148] Comparative Example 3

[0149] The preparation method of the composite-coated lithium transition metal oxide material in this comparative example includes:

[0150] Step (1): Same as in Example 2.

[0151] Step (2): Lanthanum carbonate, yttrium oxide, manganese dioxide, alumina, and lithium cobalt oxide are uniformly mixed, wherein the molar ratio of lanthanum:yttrium:manganese is 1.00:1.00:2.00, lanthanum yttrium manganese oxide accounts for 0.4% of the mass of the primary lithium cobalt oxide powder, and alumina accounts for 0.12% of the mass of the primary lithium cobalt oxide powder. The mixing equipment speed is 1300 r / min, and the time is 20 min. After the mixing is completed, it is sintered in a box furnace at 850℃ and held for 7 h to obtain blocky lanthanum yttrium manganese oxide coated lithium cobalt oxide cathode material. After crushing, it is sieved through a 500-mesh sieve to obtain nano lanthanum yttrium manganese oxide coated lithium cobalt oxide cathode material.

[0152] That is, the difference between this comparative example and Example 2 is that lanthanum yttrium manganese oxide is not prepared separately, but the coating element is added directly during the second calcination.

[0153] Comparative Example 4

[0154] The method for preparing the composite-coated lithium transition metal oxide material provided in this comparative example includes:

[0155] Step (1): Take lithium carbonate, cobalt tetroxide, titanium oxide and aluminum oxide and mix them evenly according to the molar ratio of Li:Co:Al:Ti = 1.05:1.00:0.025:0.0015 to obtain mixture 1;

[0156] Step (2): Strontium carbonate and titanium dioxide are mixed uniformly, wherein the molar ratio of strontium to titanium is 1.00:1.00, and the mixture 2 is sintered at 750℃ for 5h, and then pulverized to obtain strontium titanate oxide with a particle size of 10nm.

[0157] Step (3): Mix mixture 1 and strontium titanate oxide evenly, and obtain mixture 3 by mass ratio of mixture 1: strontium titanate oxide = 1.15: 0.01;

[0158] Step (4): Mix the above mixture 3 and alumina evenly, wherein strontium titanate oxide accounts for 0.3% of the mass of the primary lithium cobalt oxide powder and alumina accounts for 0.12% of the mass of the primary lithium cobalt oxide powder. The mixing equipment speed is 1300 r / min and the time is 20 min. After the mixing is completed, sinter in a box furnace at 850℃ and keep warm for 7 h to obtain blocky strontium titanate oxide coated lithium cobalt oxide cathode material. After crushing, pass through a 400 mesh sieve to obtain nano strontium titanate oxide coated lithium cobalt oxide cathode material.

[0159] That is, the difference between this comparative example and Example 5 is that the entire preparation process involves mixing all the raw materials and then sintering them once.

[0160] Comparative Example 5

[0161] The difference between this comparative example and Example 4 is that step (2) is omitted. That is, it is prepared only by steps (1) and (3).

[0162] Comparative Example 6

[0163] The difference between this comparative example and Example 3 is that lanthanum aluminate oxide is not prepared separately, but the coating element is added directly during the second calcination.

[0164] Test case

[0165] The lithium transition metal oxide materials coated with the composites obtained in the above embodiments and comparative examples were subjected to performance tests using the following methods:

[0166] Lithium-ion batteries are prepared using lithium transition metal oxide materials coated with composites as positive electrode materials. Specifically: positive electrode material, SP (conductive agent), and PVDF (binder) are mixed in a mass ratio of 92:4:4, NMP (N-methylpyrrolidone) is added, and the mixture is stirred to form a slurry. This slurry is then coated onto aluminum foil and dried at 80°C to form a positive electrode sheet. Graphite, SP (conductive agent), binder, and dispersant are mixed in a mass ratio of 95.5:1.5:1.5:1.5, and a solvent (H2O) is added. This slurry is then stirred, coated onto aluminum foil, and dried at 80°C to form a negative electrode sheet. The positive electrode sheet, negative electrode, electrolyte, and separator are then assembled into a pouch battery.

[0167] Capacity testing: Four pouch cells were taken as parallel samples, formed, and capacity measured. They were then charged at a constant current rate of 0.2C to voltage V1 at room temperature (25°C), and further charged under constant voltage conditions (V1) until the current dropped below 0.05C, bringing them to a fully charged state (V1). Then, they were discharged at a constant current rate of 0.2C to V2 to obtain the discharge capacity. The specific discharge capacity at 0.33C / 0.2C rate was calculated using the following formula: Specific discharge capacity = Discharge capacity / Mass of cathode material.

[0168] ① The capacity of Examples 3-4, Examples 10-11 and Comparative Examples 5-6, which are based on ternary material 622, at 2.8-4.40V / 0.33C, and the cycling at 45℃ at 2.8-4.40V / 1.0C, are shown in Table 1.

[0169] Table 1 Test Results As shown in Table 1, the materials in Examples 3, 4, 10, and 11 have composite oxides formed on their surfaces, exhibiting higher capacity and cycle retention, and lower gas production. Compared to Example 4, Example 3 shows better cycle performance and lower gas production after replacing the ABC3-type composite with the A'2B'B"C6-type composite of Example 4, but also has lower capacity. In Examples 10 and 11, partial substitution of A or B results in superior overall material performance. A comparison of Example 3 and Comparative Example 3 shows that the uncoated ABC3 composite material exhibits significantly worse capacity, cycle life, and gas production, indicating that ABC3 composite coating can improve these properties. A comparison of Example 3 and Comparative Example 6 shows that forming an ABC3 structure before coating the cathode material with a composite containing this structure is necessary to effectively improve capacity, gas production, and cycle life.

[0170] ② The capacity of Examples 1-2, 5, 8-9 and Comparative Examples 1-4 with lithium cobalt oxide as the substrate were tested at 3.0-4.50V / 0.2C and cycled at 45℃ at 3.0-4.50V / 1.0C. The results are shown in Table 2.

[0171] Table 2 Test Results As shown in Table 2, compared with Comparative Example 1, Example 5 without the M' coating composite deteriorates the material's cycling performance, while M' doping improves cycling. Compared with Comparative Example 2, Example 5 without the composite significantly worsens the material's cycling and gas generation, indicating that composite coating can improve cycling and gas generation. In Comparative Examples 3 and 4, the coating was added elementally during the second and first sintering processes, and a stable ABC3 structure was not formed before sintering. This prevented the formation of fast ion conductors and oxygen vacancies, resulting in deterioration of the corresponding material capacity, cycling performance, and gas generation.

[0172] In summary, the composite-coated lithium transition metal oxide material provided by this invention improves the phase interface through the combination of the composite and layered materials, alleviating the gas generation problem of the cathode material under high voltage. This results in better high-voltage stability of the cathode material during cycling, thereby enabling the lithium-ion battery to achieve high-voltage cycle capacity retention and improving the performance of the lithium-ion battery. Furthermore, by using the ABC3 composite coating, the lithium-ion conductivity on the surface of the lithium transition metal oxide material is improved, and the corrosion of the cathode surface by the electrolyte is reduced. The resulting lithium transition metal oxide material exhibits good cycle performance, low impedance, and low gas generation.

[0173] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention. For example, ternary 622 can be ternary 333, ternary 523, ternary 71515, ternary 811, and ternary 90505, etc. It can cover other structures such as LNO and LCO. Some steps in various embodiments of the method may be optional, or new steps may be added; or any combination of two / more of the above embodiments. Such modifications, variations, or combinations also fall within the scope of the present invention.

Claims

1. A composite-coated lithium transition metal oxide material, characterized in that, The lithium transition metal oxide material coated by the composite includes a lithium transition metal oxide material and a composite material coated on the surface of the lithium transition metal oxide material. The chemical formula of the lithium transition metal oxide material is Li a M 1-b M′ b O2, where 0.98 ≤ a ≤ 1.03, 0 < b ≤ 0.1, the M-type elements include at least one of Ni, Co, and Mn; the M′-type elements include at least one of Ba, La, Ti, Zr, V, Nb, Cu, Mg, B, S, Sr, Al, Sc, Y, Ga, Zn, W, Mo, Si, Sb, and Ca; The complex has the chemical formula ABC3, wherein elements of class A include at least one of Pb, Na, Sn, Sr, K, Ca, Ba, Sr, Ln, Pr, Sm, Gd, Bi, Cs, Ca, and La; elements of class B include at least one of Ti, Y, Zn, Fe, Ta, Mn, Co, Ni, Mo, Nb, W, Pb, and Al; and elements of class C include at least one of F, Cl, Br, I, and O. When the B-type element in the composite has the same element as the M-type element in the lithium transition metal oxide material, the chemical state of the same element in the composite is different from the chemical state in the lithium transition metal oxide material. The complex is an ABO3 complex oxide, wherein the cations corresponding to the A-type elements have a 12-coordinate structure and are located in the cavities formed by octahedrons; the transition metal ions corresponding to the B-type elements form octahedral coordination with six oxygen ions; or, in the ABO3 complex oxide, the B-type elements form a regular octahedral symmetric structure with O, and the B-type elements are located at the center of the octahedrons, forming a cubic symmetric structure; the A-type elements are distributed at the center of the octahedrons, forming a cube.

2. The lithium transition metal oxide material coated with the composite according to claim 1, characterized in that, The lithium transition metal oxide material coated by the composite has at least one of the following characteristics: Feature 1: The lithium transition metal oxide material has a layered structure; Feature 2: The mass of the composite does not exceed 5% of the mass of the lithium transition metal oxide material coated by the composite.

3. The lithium transition metal oxide material coated with the composite according to claim 2, characterized in that, The mass of the composite does not exceed 3% of the mass of the lithium transition metal oxide material coated by the composite.

4. The lithium transition metal oxide material coated with the composite according to claim 1, characterized in that, The ABO3 composite oxide is selected from LaMnO3, BiFeO3, CsPbI3, CaTiO3, BaTiO3, SnTiO3, PbTiO3, KTaO3, LaFeO3, LaNiO3, SrTiO3 or LaAlO3.

5. The lithium transition metal oxide material coated with the composite according to claim 1, characterized in that, The A-type elements in the complex are composed of A' and A'', and the B-type elements are composed of B' and B''. The chemical formula of the complex is A'A''B'B''O6; wherein A' and A'' are different elements and B' and B'' are the same element, A' is a lanthanide element and the radius of A'' is larger than the radius of A'; B' and B'' are both elements with variable valence states.

6. The lithium transition metal oxide material coated with the composite according to claim 5, characterized in that, A'A''B'B''O6 is selected from YSmFe2O6, YPrFe2O6, YPrMn2O6, YPrCo2O6, or YLaMn2O6.

7. The lithium transition metal oxide material coated with the composite according to claim 1, characterized in that, The A-type elements in the complex are composed of A' and A'', and the B-type elements are composed of B' and B''. The chemical formula of the complex is A'A''B'B''O6; wherein B' and B'' are different elements and A' and A'' are the same element, A' and A'' are both alkaline earth metal elements, B' and B'' are both transition metal elements, and the valence state of B'' is higher than that of B'.

8. The lithium transition metal oxide material coated with the composite according to claim 7, characterized in that, A'A''B'B''O6 is selected from Ca2FeWO6, Ca2NiMoO6, Ba2NiNbO6, or Sr2NiWO6.

9. A method for preparing a lithium transition metal oxide material coated with a composite as described in any one of claims 1 to 8, characterized in that, Includes the following steps: The primary lithium transition metal oxide powder prepared from lithium source, M source and part of M′ source, the ABC3 composite powder prepared from A source, B source and C source, and the remaining M′ source are mixed and sintered.

10. The preparation method according to claim 9, characterized in that, The lithium transition metal oxide primary powder, the ABC3 composite powder, and the remaining M′ are mixed at a rotation speed of 500 r / min to 1500 r / min.

11. The preparation method according to claim 9, characterized in that, The mixing time for the primary lithium transition metal oxide powder, the ABC3 composite powder, and the remaining M′ source is 10 min to 60 min.

12. The preparation method according to claim 9, characterized in that, The sintering temperature is 300℃~1050℃.

13. The preparation method according to claim 12, characterized in that, The sintering temperature is 500℃~950℃.

14. The preparation method according to claim 9, characterized in that, The sintering time is 1 hour to 10 hours.

15. The preparation method according to claim 14, characterized in that, The sintering time is 2 hours to 8 hours.

16. The preparation method according to claim 9, characterized in that, The preparation of the lithium transition metal oxide primary powder includes: mixing the lithium source, the M source and a portion of the M′ source, followed by calcination and crushing.

17. The preparation method according to claim 16, characterized in that, The lithium source includes at least one of lithium carbonate and lithium hydroxide.

18. The preparation method according to claim 16, characterized in that, The M source includes at least one of oxides of M-type elements and hydroxides of M-type elements.

19. The preparation method according to claim 18, characterized in that, The M source includes at least one of cobalt tetroxide, cobalt hydroxyoxide, cobalt carbonate, cobalt hydroxide, nickel cobalt manganese oxide, nickel cobalt manganese hydroxide, manganese hydroxide, nickel hydroxide, nickel oxide, and manganese oxide.

20. The preparation method according to claim 16, characterized in that, The M′ source includes at least one of the following: oxides of M′ type elements, hydroxides of M′ type elements, acetates of M′ type elements, and carbonates of M′ type elements.

21. The preparation method according to claim 16, characterized in that, The calcination temperature of the mixture of the lithium source, the M source, and a portion of the M′ source is 650℃~1200℃.

22. The preparation method according to claim 21, characterized in that, The calcination temperature of the mixture of the lithium source, the M source, and part of the M′ source is 850℃~1080℃.

23. The preparation method according to claim 16, characterized in that, The calcination time for the mixture of the lithium source, the M source, and a portion of the M′ source is 5h to 15h.

24. The preparation method according to claim 23, characterized in that, The calcination time for the mixture of the lithium source, the M source, and a portion of the M′ source is 6h to 13h.

25. The preparation method according to claim 16, characterized in that, The primary lithium transition metal oxide powder has a particle size of 2μm to 25μm.

26. The preparation method according to claim 9, characterized in that, The preparation of the ABC3 composite powder includes: mixing the A source, the B source and the C source and then sintering them.

27. The preparation method according to claim 26, characterized in that, The A source includes at least one of oxides of A-type elements, hydroxides of A-type elements, acetates of A-type elements, and carbonates of A-type elements.

28. The preparation method according to claim 26, characterized in that, The B source includes at least one of oxides of B-type elements, hydroxides of B-type elements, acetates of B-type elements, and carbonates of B-type elements.

29. The preparation method according to claim 26, characterized in that, The sintering temperature of the mixture of source A, source B and source C is 700℃~1350℃.

30. The preparation method according to claim 29, characterized in that, The sintering temperature of the mixture of source A, source B and source C is 800℃~1250℃.

31. The preparation method according to claim 26, characterized in that, The sintering time for the mixture of source A, source B, and source C is 3 to 12 hours.

32. The preparation method according to claim 31, characterized in that, The sintering time for the mixture of source A, source B, and source C is 5 to 10 hours.

33. The preparation method according to claim 26, characterized in that, The particle size of the ABC3 composite powder is 1 nm to 20 μm.

34. The preparation method according to claim 33, characterized in that, The particle size of the ABC3 composite powder is 5nm~10μm.

35. A positive electrode plate, characterized in that, The active material in the positive electrode includes the lithium transition metal oxide material coated with the composite as described in any one of claims 1 to 8.

36. A battery, characterized in that, The battery contains the positive electrode sheet as described in claim 35.

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