Metal oxide material, preparation method and application

Abstract

The invention discloses a metal oxide material, a preparation method and application. The metal oxide material comprises a first layered metal oxide and a second layered metal oxide, in an XRD (X-Ray Diffraction) pattern of the first layered metal oxide, characteristic peaks respectively exist at positions where 2 theta is 18.85 degrees to 19.05 degrees, 37.0 degrees to 37.8 degrees and 45 degrees to 46 degrees; an XRD (X-Ray Diffraction) pattern of the second layered metal oxide meets I1 > I2 > I3, wherein I1, I2 and I3 are peak height intensities of characteristic peaks at 2theta = 18.4 degrees to 18.7 degrees, 38 degrees to 38.6 degrees and 46.8 degrees to 47.6 degrees respectively. According to the metal oxide material provided by the invention, the compaction density and the energy density of the positive electrode material can be improved, so that the positive electrode material has better high-voltage stability in the cycle process, the cycle capacity retention ratio and the energy density of the lithium ion battery under high voltage are further improved, and the performance of the lithium ion battery is improved.

Description

Technical Field

[0001] This invention relates to the field of cathode material technology, and more specifically, to metal oxide materials, preparation methods, and applications. Background Technology

[0002] Layered cathode materials for lithium-ion batteries have become one of the most widely used cathode systems in commercial applications due to their high capacity, excellent cycle life, high discharge platform, and outstanding compaction density. With the expansion of the electric vehicle and 3C product markets and the increasing demand for extended driving range from consumers, the industry urgently needs solutions with higher energy density. At the same time, it places higher demands on comprehensive performance such as low internal resistance, high rate capability, fast charging, and long lifespan, forming an important research direction beyond high voltage.

[0003] Traditional approaches to improving energy density have limitations: increasing compaction density through particle gradation has reached its physical limit, with diminishing marginal returns; while raising the charging cutoff voltage can increase reversible lithium insertion / extraction, it exacerbates structural degradation, narrows the safety window, and leads to decreased cycle life and thermal stability. Existing processes cannot offset the deep structural damage caused by high voltage, and cannot simultaneously achieve multiple core performance indicators. Therefore, developing novel cathode materials with stable crystal structures under high voltage, excellent compaction density, and the ability to release more active lithium has become a core pursuit of the industry.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide metal oxide materials, preparation methods and applications that are advantageous in balancing energy density and cycle life.

[0006] This invention is implemented as follows: In a first aspect, the present invention provides a metal oxide material, comprising a first layered metal oxide and a second layered metal oxide; In the XRD pattern of the first layered metal oxide, characteristic peaks exist at 2θ of 18.85°-19.05°, 37.0°-37.8°, and 45°-46°, respectively; The XRD pattern of the second layered metal oxide satisfies I1>I2>I3, where I1 is the peak intensity of the characteristic peak at 2θ=18.4°-18.7°, I2 is the peak intensity of the characteristic peak at 2θ=38°-38.6°, and I3 is the peak intensity of the characteristic peak at 2θ=46.8°-47.6°.

[0007] In an optional embodiment, the XRD pattern of the metal oxide material has a set of characteristic split double peaks between 2θ = 18° and 20°, wherein the ratio of the peak height intensity of the low-angle peak to the high-angle peak in the split double peak is n, and satisfies 0.05 ≤ n ≤ 0.25. And / or, the ratio of the peak high intensities of I2 and I3 is 1 - 3.5.

[0008] In an optional embodiment, the proportion of the number of agglomerated particles in the metal oxide material is less than 10%; And / or, the mass ratio of the second layered metal oxide to the total mass of the first layered metal oxide and the second layered metal oxide is less than 10%.

[0009] In an optional embodiment, the Dn50 of the first layered metal oxide is 1.5 μm to 12 μm; And / or, the Dn50 of the second layered metal oxide is 1.0 μm to 9.0 μm; And / or, the ratio of the Dn50 of the first layered metal oxide to the Dn50 of the second layered metal oxide is 2.0 - 5.5.

[0010] In an optional embodiment, the chemical formula of the metal oxide material is (1 - x)Li a M 1-b M′ b O2·xLi c M 1-d M′′ d O2, where 0 < x ≤ 0.1, 0.98 ≤ a ≤ 1.03, 0 < b ≤ 0.1, 0.98 ≤ c ≤ 1.03, 0 < d ≤ 0.1, M includes at least one of Ni, Co, and Mn, M′ includes at least one of Ba, La, Ti, Zr, V, Nb, Cu, Mg, B, Sr, Al, Sc, Y, Ga, Zn, W, Mo, Si, Sb, Ta, and Ca, and M′′ includes at least one of Ba, La, Ti, Zr, V, Nb, Cu, Mg, B, Sr, Al, Sc, Y, Ga, Zn, W, Mo, Si, Sb, Ta, and Ca; And / or, the chemical formula of the first layered metal oxide is Li a M 1-b M′ b O2, where 0.98 ≤ a ≤ 1.03, 0 < b ≤ 0.1, M includes at least one of Ni, Co, and Mn, and M′ includes at least one of Ba, La, Ti, Zr, V, Nb, Cu, Mg, B, Sr, Al, Sc, Y, Ga, Zn, W, Mo, Si, Sb, Ta, and Ca; And / or, the chemical formula of the second layered metal oxide is Li c M 1-d M′′ dO2, where 0.98 ≤ c ≤ 1.03, 0 < d ≤ 0.1, M includes at least one of Ni, Co, and Mn, and M'' includes at least one of Ba, La, Ti, Zr, V, Nb, Cu, Mg, B, Sr, Al, Sc, Y, Ga, Zn, W, Mo, Si, Sb, Ta, and Ca.

[0011] In a second aspect, the present invention provides a method for preparing the metal oxide material described in the foregoing embodiments, including: mixing a first layered metal oxide and a second layered metal oxide to obtain the metal oxide material.

[0012] In an optional embodiment, the rotation speed of the mixing is 300 r / min to 1500 r / min, and the time is 10 min to 240 min.

[0013] In an optional embodiment, the preparation of the first layered metal oxide includes: mixing a lithium source, a large particle M source, and an M' source, then calcining and crushing to obtain large particle primary products; mixing a lithium source, a small particle M source, and an M' source, then calcining and crushing to obtain small particle primary products; mixing the large particle primary products and the small particle primary products, sintering, and pulverizing to obtain the first layered metal oxide; And / or, the preparation of the second layered metal oxide includes: mixing a sodium source, an M source, and an M'' source, then successively performing calcination, crushing, molten salt ion exchange, washing, and drying to obtain the second layered metal oxide.

[0014] In an optional embodiment, during the preparation of the first layered metal oxide, the calcination temperature is 800°C to 1200°C, and the heat preservation time is 5 h to 15 h; And / or, the Dn50 of the large particle primary products is 8 μm to 14 μm, the Dn50 of the small particle primary products is 2 μm to 7 μm, and the mass ratio of the large particle primary products to the small particle primary products is (2.5 - 4.5):1; And / or, the sintering temperature is 800°C - 1000°C, and the heat preservation time is 8 h - 12 h; And / or, during the preparation of the second layered metal oxide, the calcination temperature is 400°C to 900°C, and the heat preservation time is 5 h to 25 h; And / or, the molten salt ion exchange step includes: mixing an intermediate product obtained by calcination and crushing during the preparation of the second layered metal oxide with a lithium salt and performing molten salt ion exchange, where the molar ratio of lithium element in the lithium salt to sodium element in the intermediate product is (30 ~ 5):1; And / or, the temperature of the molten salt ion exchange is 60~180°C, the pH is 8.0~10.5, and the time is 2 h to 25 h; And / or, the drying temperature is 100℃-200℃, and the time is 10h-15h.

[0015] Thirdly, the present invention provides a battery comprising the metal oxide material described in any one of the foregoing embodiments.

[0016] The present invention has the following beneficial effects: The metal oxide material provided in this application, through the combination of a first layered metal oxide and a second layered metal oxide, can improve the compaction density and energy density of the cathode material, enabling the cathode material to have better high voltage stability during cycling, thereby improving the cycle capacity retention rate and energy density of the lithium-ion battery under high voltage and enhancing the performance of the lithium-ion battery. Attached Figure Description

[0017] 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.

[0018] Figure 1 The image shows the XRD pattern of the second layered metal oxide in Example 1. Figure 2 The XRD pattern of the second layered metal oxide in Comparative Example 3; Figure 3 This is a SEM image of the second layered metal oxide in Example 1; Figure 4 This is a SEM image of the second layered metal oxide in Comparative Example 3. Detailed Implementation

[0019] 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 clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0020] This invention provides a metal oxide material, comprising a first layered metal oxide and a second layered metal oxide; In the XRD pattern of the first layered metal oxide, characteristic peaks exist at 2θ of 18.85°-19.05°, 37.0°-37.8°, and 45°-46°, respectively; The XRD pattern of the second layered metal oxide satisfies I1>I2>I3, where I1 is the peak intensity of the characteristic peak at 2θ=18.4°-18.7°, I2 is the peak intensity of the characteristic peak at 2θ=38°-38.6°, and I3 is the peak intensity of the characteristic peak at 2θ=46.8°-47.6°.

[0021] The metal oxide material provided in this application, through the combination of a first layered metal oxide and a second layered metal oxide, can improve the compaction density and energy density of the cathode material, enabling the cathode material to have better high voltage stability during cycling, thereby improving the cycle capacity retention rate and energy density of the lithium-ion battery under high voltage and enhancing the performance of the lithium-ion battery.

[0022] Specifically: In this application, the first-layered metal oxide particles are not easy to grow, resulting in insufficient compaction density and affecting the volumetric energy density. Compared with the first-layered metal oxide, the second-layered metal oxide has more phase transitions during high-voltage charge-discharge, and the volumetric deformation of each phase transition is relatively small, resulting in a smoother phase transition process. This leads to less stress accumulation during cycling and a more stable structure. It also has shorter MO bonds and wider ion channels, exhibiting a stronger oxygen-fixing effect, which is beneficial for improving rate performance and increasing capacity. However, the second-layered metal oxide is a low-temperature phase and will gradually transform back into the first-layered metal oxide at temperatures above 300°C, thus negating its electrical performance advantages. Furthermore, the second-layered metal oxide is prone to oriented growth, resulting in poor morphology, which also affects the compaction density and consequently the energy density. The I2 and I3 atoms in the second-layered metal oxide of this application allow for preferred orientation growth of the crystal planes, improving particle roundness and compaction density. Furthermore, by mixing the first layered metal oxide with the second layered metal oxide, the second layered metal oxide effectively suppresses oxygen loss and slows down phase transition stress under high delithiation state, resulting in a significant improvement in rate capability and capacity. Meanwhile, the first layered metal oxide maintains high flat density and thermodynamic stability, which is beneficial for improving volumetric energy density and cycle performance.

[0023] Furthermore, by introducing a second layered metal oxide into the first layered metal oxide, the metal oxide material has larger lithium-ion channels and stronger MO bonds, which improves the lithium-ion conductivity of the metal oxide material, reduces the corrosion of the positive electrode surface by the electrolyte, and enables the metal oxide material as a positive electrode material to have better capacity, good cycle performance, and higher ionic conductivity.

[0024] It should be noted that the position or intensity of the characteristic peaks corresponding to the XRD patterns of the first and second layered metal oxides can reflect phenomena such as lattice distortion in the material. If the position or intensity of the characteristic peaks corresponding to the XRD patterns of the first and second layered metal oxides do not meet the above requirements, it means that the growth may not be preferentially oriented or a phase transition may have occurred.

[0025] It should also be noted that the first layered metal oxide refers to the phase in which lithium, other metal elements besides lithium, and oxygen elements are stacked in the manner of αβγαβγαβγ, i.e., the H phase; the second layered metal oxide refers to the phase in which lithium, other metal elements besides lithium, and oxygen elements are stacked in the manner of αβγβαβγβ, i.e., the W phase; where α refers to lithium atoms, β refers to other metal atoms besides lithium, and γ refers to oxygen atoms.

[0026] In an optional embodiment, the XRD pattern of the metal oxide material exhibits a characteristic split doublet at 2θ = 18°-20°. The ratio of the peak height intensity of the low-angle peak to the high-angle peak in the split doublet is n, satisfying 0.05 ≤ n ≤ 0.25, for example, 0.05, 0.07, 0.09, 0.11, 0.13, 0.15, 0.17, 0.19, 0.21, 0.23, 0.25. The value of n is related to the proportion of the first layered metal oxide and the second layered metal oxide in the metal oxide material, as well as the crystallinity of the second layered metal oxide.

[0027] In an optional embodiment, the ratio of the peak height intensity of I2 and I3 is 1-3.5, for example, 1, 1.5, 2, 2.5, 3, 3.5, which is more conducive to the preferential orientation growth of the second layered metal oxide crystal plane, improves the roundness of the particles, and improves the compaction density.

[0028] In optional embodiments, the proportion of agglomerated particles in the metal oxide material is less than 10%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%. The lithium metal oxide material of the present invention has a low proportion of agglomerated particles and more dense particle packing, which can reduce the proportion of voids and inactive components. In addition, fewer grain boundaries can reduce lithium diffusion resistance and fully release capacity. At the same time, it can alleviate volume expansion and particle cracking, reduce grain boundary side reactions, delay performance decay, and achieve synergistic optimization of energy density and cycle performance.

[0029] In an optional embodiment, the mass ratio of the second layered metal oxide to the total mass of the first and second layered metal oxides is less than 10%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, which is beneficial for balancing capacity and cycle performance.

[0030] In an optional embodiment, the Dn50 of the first layered metal oxide is 1.5 μm to 12 μm, such as 1.5 μm, 2.0 μm, 2.5 μm, 3.0 μm, 3.5 μm, 4.0 μm, 4.5 μm, 5.0 μm, 5.5 μm, 6 μm, 6.5 μm, 7.0 μm, 7.5 μm, 8.0 μm, 8.5 μm, 9.0 μm, 9.5 μm, 10.0 μm, 10.5 μm, 11.0 μm, 11.5 μm, 12 μm.

[0031] In an optional embodiment, the Dn50 of the second layered metal oxide is 1.0 μm to 9.0 μm, such as 1.0 μm, 1.8 μm, 2.6 μm, 3.4 μm, 4.2 μm, 5.0 μm, 5.8 μm, 6.6 μm, 7.4 μm, 8.2 μm, 9.0 μm; In an optional embodiment, the ratio of the Dn50 of the first layered metal oxide to the second layered metal oxide is 2.0 - 5.5, such as 2.0, 2.3, 2.5, 2.8, 3.1, 3.4, 3.7, 4.0, 4.3, 4.6, 4.9, 5.2, 5.5.

[0032] The reasonable grading of the first layered metal oxide and the second layered metal oxide can optimize the compactness of particle packing. The second layered metal oxide particles fill the pores of the first layered metal oxide particles, increasing the proportion of active materials, reducing non-active components and voids, thereby improving the energy density; at the same time, it can reduce the interfacial impedance and lithium diffusion resistance, inhibit volume expansion, particle cracking and side reactions, relieve structural collapse and performance degradation, and achieve the synergistic improvement of energy density and cycle performance.

[0033] In an optional embodiment, the chemical formula of the metal oxide material is (1 - x)Li a M 1-b M′ b O2·xLi c M 1-d M′′ d O2, where 0 < x ≤ 0.1, 0.98 ≤ a ≤ 1.03, 0 < b ≤ 0.1, 0.98 ≤ c ≤ 1.03, 0 < d ≤ 0.1, M includes at least one of Ni, Co, and Mn, M′ includes at least one of Ba, La, Ti, Zr, V, Nb, Cu, Mg, B, Sr, Al, Sc, Y, Ga, Zn, W, Mo, Si, Sb, Ta, and Ca, and M′′ includes at least one of Ba, La, Ti, Zr, V, Nb, Cu, Mg, B, Sr, Al, Sc, Y, Ga, Zn, W, Mo, Si, Sb, Ta, and Ca; In an optional embodiment, the chemical formula of the first layered metal oxide is Li a M 1-b M′ b O2, where 0.98 ≤ a ≤ 1.03, 0 < b ≤ 0.1, M includes at least one of Ni, Co, and Mn, and M′ includes at least one of Ba, La, Ti, Zr, V, Nb, Cu, Mg, B, Sr, Al, Sc, Y, Ga, Zn, W, Mo, Si, Sb, Ta, and Ca; In an optional embodiment, the chemical formula of the second layered metal oxide is Li c M 1-d M′′ d O2, where 0.98 ≤ c ≤ 1.03, 0 < d ≤ 0.1, M includes at least one of Ni, Co, and Mn, and M′′ includes at least one of Ba, La, Ti, Zr, V, Nb, Cu, Mg, B, Sr, Al, Sc, Y, Ga, Zn, W, Mo, Si, Sb, Ta, and Ca.

[0034] In this application, the doping element can preferentially adsorb a certain basal plane, depressing the surface energy of the basal plane; in order to "preserve" the low-energy plane, the crystal can only stack perpendicular to a certain crystal plane continuously, causing the particles to change their original morphology and undergo preferred orientation growth. However, the doping amount and doping element need to be controlled within a suitable range. Excessive doping or an unreasonable doping element may instead cause secondary phases or cation mixing, and the degree of orientation may instead decrease.

[0035] Furthermore, after the doping element enters the Co site, it can introduce Li + vacancies, reduce the lattice anisotropic strain, inhibit the stacking speed of crystal planes, make the growth rates of the c-axis and the ab-plane tend to be consistent, which is beneficial to the transformation of the particles from "plate-like" to "elliptical-nearly spherical", and further beneficial to improving the compaction density and energy density.

[0036] The embodiment of the present invention also provides a preparation method of the metal oxide material described in the foregoing embodiment, including: mixing the first layered metal oxide and the second layered metal oxide to obtain the metal oxide material.

[0037] In an optional embodiment, the mixing speed is 300 r / min to 1500 r / min, for example, 300 r / min, 430 r / min, 560 r / min, 690 r / min, 820 r / min, 950 r / min, 1080 r / min, 1210 r / min, 1340 r / min, 1470 r / min, or 1500 r / min; and the mixing time is 10 min to 240 min, for example, 10 min, 35 min, 60 min, 85 min, 110 min, 135 min, 160 min, 185 min, 210 min, 235 min, or 240 min. Thorough mixing helps ensure the uniformity of the properties of the metal oxide material.

[0038] In an optional embodiment, the preparation of the first layered metal oxide includes: mixing a lithium source, large-particle M source and M′ source, calcining and crushing them to obtain a large-particle primary product; mixing a lithium source, small-particle M source and M′ source, calcining and crushing them to obtain a small-particle primary product; and mixing the large-particle primary product and the small-particle primary product, sintering and pulverizing them to obtain the first layered metal oxide.

[0039] During the sintering process after mixing large and small primary particles, lithium migrates from high-concentration areas to low-concentration areas, which promotes a more uniform distribution of lithium and other elements and improves performance stability. It should be noted that doping elements can be added during sintering. This promotes lithium-ion insertion / extraction and, more importantly, the doping coating on the surface of the first-layered metal oxide improves its stability.

[0040] In an optional embodiment, the preparation of the second layered metal oxide includes: mixing a sodium source, an M source, and an M′′ source, and then sequentially calcining, crushing, molten salt ion exchange, washing, and drying to obtain the second layered metal oxide.

[0041] In an optional embodiment, during the preparation of the first layered metal oxide, the calcination temperature is 800℃~1200℃, for example 800℃, 840℃, 880℃, 920℃, 960℃, 1000℃, 1040℃, 1080℃, 1120℃, 1160℃, 1200℃; the holding time is 5h~15h, for example 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h. Calcination under these conditions is beneficial for the integrity of the layered structure of the layered metal oxide and low ion mixing, thereby improving energy density and cycle stability. Too high or too low temperatures will lead to lithium volatilization, structural defects, etc., which will result in a decrease in energy density and cycle stability.

[0042] In an optional embodiment, the Dn50 of the large-particle primary product is 8μm~14μm, for example, 8μm, 8.4μm, 8.8μm, 9.2μm, 9.6μm, 10μm, 10.4μm, 10.8μm, 11.2μm, 11.6μm, 12.0μm, 12.4μm, 12.8μm, 13.2μm, 13.6μm, 14μm; the Dn50 of the small-particle primary product is 2μm~7μm, for example, 2μm, 2.5μm, 3.0μm, 3.5μm, 4.0μm, 4.5μm, 5.0μm, 5.5μm, 6.0μm, 6.5μm, 7μm. μm; the mass ratio of the large-particle primary product to the small-particle primary product is (2.5-4.5):1, for example 2.5:1, 2.7:1, 2.9:1, 3.1:1, 3.3:1, 3.5:1, 3.7:1, 3.9:1, 4.1:1, 4.3:1, 4.5:1; In the first-layer metal oxide, a reasonable gradation of large and small primary particles can optimize particle packing density. Small primary particles fill the pores of large primary particles, increasing the proportion of active material and reducing inactive components and voids, thereby improving energy density. At the same time, it can reduce interfacial impedance and lithium diffusion resistance, suppress volume expansion, particle cracking and side reactions, alleviate structural collapse and performance degradation, and achieve a synergistic improvement in energy density and cycle performance. It should be noted that the first layered metal oxide in this application can be a large-particle primary product and a small-particle primary product can be obtained by mixing, sintering and then crushing as described above. In this case, the Dn50 of the first layered metal oxide is preferably 7μm to 12μm, and preferably the ratio of the Dn50 of the first layered metal oxide and the second layered metal oxide is 2.0-5.5. If a primary product with a suitable particle size is used directly without gradation, then the Dn50 of the first layered metal oxide is preferably 1.5μm to 4.5μm, and the ratio of the first layered metal oxide and the second layered metal oxide can be between 2.0 and 5.5, or it can be outside of 2.0-5.5.

[0043] In an optional embodiment, the sintering temperature is 800℃-1000℃, for example 800℃, 820℃, 840℃, 860℃, 880℃, 900℃, 920℃, 940℃, 960℃, 980℃, or 1000℃; the holding time is 8h-12h, for example 8h, 8.4h, 8.8h, 9.2h, 9.6h, 10.0h, 10.4h, 10.8h, 11.2h, 11.6h, or 12h; this is beneficial for improving the stability of the first layered metal oxide, thereby improving the cycle performance of the battery using the metal oxide material.

[0044] In an optional embodiment, during the preparation of the second layered metal oxide, the calcination temperature is 400℃~900℃, for example 400℃, 450℃, 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, and 900℃; the holding time is 5h~25h, for example 5h, 7h, 9h, 11h, 13h, 15h, 17h, 19h, 21h, 23h, and 25h. Calcination under these conditions is beneficial for maintaining the integrity of the layered structure of the layered metal oxide and reducing ion mixing, which is beneficial for improving the energy density and cycle stability of the second layered metal oxide obtained after molten salt ion exchange.

[0045] In an optional embodiment, the molten salt ion exchange step includes: mixing the intermediate product obtained by calcination and crushing during the preparation of the second layered metal oxide with lithium salt and performing molten salt ion exchange, wherein the molar ratio of lithium in the lithium salt to sodium in the intermediate product is (30~5):1, for example 30:1, 27:1, 24:1, 21:1, 18:1, 15:1, 12:1, 9:1, 6:1, 5:1; an appropriate lithium-sodium molar ratio can promote sufficient molten salt ion exchange, allowing the layered lithium metal oxide to form a complete layered structure, expanding the interlayer spacing, reducing ion mixing and impedance, and improving energy density and lithium diffusion efficiency. An imbalanced ratio can lead to incomplete exchange or structural distortion, resulting in insufficient capacity release, increased volume expansion during cycling, and significantly weakening the battery's energy density and cycle stability.

[0046] In an optional embodiment, the temperature of molten salt ion exchange is 60~180℃, for example 60℃, 73℃, 86℃, 99℃, 112℃, 125℃, 138℃, 151℃, 164℃, 177℃, 180℃; the pH is 8.0~10.5, for example 8.0, 8.3, 8.6, 8.9, 9.2, 9.5, 9.8, 10.1, 10.4, 10.5; the time is 2h~25h, for example 2h, 4.6h, 7.2h, 9.8h, 12.4h, 15h, 17.6h, 20.2h, 22.8h, 25h; exceeding this range will lead to a decrease in the stability of the second layered metal oxide.

[0047] In optional embodiments, the drying temperature is 100℃-200℃, for example 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃; the time is 10h-15h, for example 10h, 10.5h, 11h, 11.5h, 12h, 12.5h, 13h, 13.5h, 14h, 14.5h, 15h. A suitable drying temperature can efficiently remove residual moisture after washing, avoid the formation of impurity phases on the material surface, and ensure the integrity of the layered structure and electrochemical stability. Excessively high temperatures can easily lead to lithium volatilization and increased grain boundary defects, while excessively low temperatures can induce side reactions due to residual moisture. Both will increase impedance, accelerate performance degradation, and are detrimental to the synergistic improvement of energy density and cycle performance.

[0048] This application adjusts the doping elements and parameters in the preparation process to make the I2 of the second layered metal oxide greater than the I3, thereby improving the particle morphology and sphericity, so that it can have a higher compaction density after being graded with the first layered metal oxide, and thus have a higher volumetric energy density.

[0049] The present invention also provides a battery comprising the metal oxide material described in any one of the foregoing embodiments.

[0050] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0051] Example 1 This embodiment provides a method for preparing a metal oxide material, including the following steps: (1) Lithium carbonate, cobalt tetroxide, zirconium oxide, and aluminum oxide were weighed and uniformly mixed with a molar ratio of n(Li):n(Co):n(Zr):n(Al) = 1.065:1.00:0.005:0.071. The mixture was calcined at 1060℃ for 10 hours and then crushed to obtain large-particle primary products with the chemical formula LiCo.0.9294 Zr 0.0046 Al 0.0660 O2, corresponding to a particle size Dn50=12.0μm.

[0052] (2) Lithium carbonate, cobalt tetroxide, zirconium oxide, and aluminum oxide were weighed and uniformly mixed in a molar ratio of n(Li):n(Co):n(Zr):n(Al) = 1.051:1.00:0.005:0.071. The mixture was then calcined at 1020℃ for 10 hours and then crushed to obtain small granular primary products with the chemical formula LiCo. 0.9294 Zr 0.0046 Al 0.0660 O2, corresponding to a particle size Dn50=3.0μm.

[0053] (3) The primary product includes large-particle primary products and small-particle primary products, and the mass ratio (approximately equal to the molar ratio) of the large and small primary products is 4.00:1.00. The molar ratio n(primary product):n(Ti):n(Al) = 1.00:0.001:0.001 is used to weigh the primary product, titanium oxide, and aluminum oxide, mix them evenly, sinter them at 850℃ for 10h, and then crush them to obtain the first layered metal oxide with the chemical formula LiCo. 0.9275 Zr 0.0046 Ti 0.001 Al 0.0669 O2, corresponding to a particle size Dn50=10.5μm.

[0054] (4) Prepare a cobalt sulfate solution with a concentration of 1 mol / L, a sodium hydroxide solution with a concentration of 1.0 mol / L, and an ammonia solution with a concentration of 6.5 mol / L. Add the cobalt sulfate solution, sodium hydroxide solution, and ammonia solution to the reaction equipment in a flow ratio of 1.00:1.35:0.55 according to the volume flow rate. Adjust the pH of the reaction system to 10.5 and stir for 2 hours. Then lower the pH to 9 and continue the reaction for 8 hours. The temperature of the reaction solution is 70°C. Nitrogen gas is introduced for protection. The solid-liquid ratio in the reaction vessel is 1:5. Continue the reaction for 100 hours to obtain a slurry of cobalt hydroxide. After washing and aging, cobalt hydroxide with uniform particle size is obtained. After calcination at 700°C and sieving, cobalt tetroxide with Dn50=3.6μm is obtained.

[0055] (5) Weigh out sodium carbonate, cobalt tetroxide (Dn50=3.6μm), nickel oxide, and aluminum oxide in a molar ratio of n(Na):n(Co):n(Ni):n(Al) = 0.76:1.00:0.020:0.050, mix them uniformly, and keep them at 750℃ for 20h to obtain the transition sodium-electric material Na. 0.75 Co 0.9346 Ni 0.0187 Al 0.0467O2; A transition sodium-ion battery material was mixed with lithium chloride and lithium nitrate, with a sodium:lithium chloride:lithium nitrate molar ratio of 1:2:6. Ion exchange was performed at 85℃ and pH=9.5 for 2 hours. After ion exchange, the system was washed and dried at 100℃ for 10 hours to obtain a second-layer metal oxide, LiCo. 0.9346 Ni 0.0187 Al 0.0467 O2, corresponding to Dn50=3.2μm, XRD pattern as follows Figure 1 As shown, the SEM image is as follows: Figure 3 As shown.

[0056] (6) The first layered metal oxide and the second layered metal oxide were mixed uniformly at a molar ratio of 19:1 at a rotation speed of 1000 r / min for 30 min to obtain a metal oxide material with the chemical formula 0.95 LiCo. 0.9275 Zr 0.0046 Ti 0.001 Al 0.0669 O2·0.05 LiCo 0.9346 Ni 0.0187 Al 0.0467 O2 corresponds to Dn50=10.3μm.

[0057] Example 2 This embodiment provides a method for preparing a metal oxide material, including the following steps: (1) Lithium carbonate, cobalt hydroxide, magnesium oxide, and aluminum oxide were weighed and uniformly mixed in a molar ratio of n(Li):n(Co):n(Mg):n(Al) = 1.075:1.00:0.005:0.071. The mixture was calcined at 1065℃ for 10 hours and then crushed to obtain large-particle primary products with the chemical formula LiCo. 0.9294 Mg 0.0046 Al 0.0660 O2. Corresponding particle size Dn50 = 12.5 μm.

[0058] (2) Lithium carbonate, cobalt hydroxide, magnesium oxide, and aluminum oxide were weighed and uniformly mixed in a molar ratio of n(Li):n(Co):n(Mg):n(Al) = 1.045:1.00:0.005:0.071. The mixture was then calcined at 1010℃ for 10 hours and then crushed to obtain small granular primary products with the chemical formula LiCo. 0.9294 Mg 0.0046 Al 0.0660 O2. Corresponding particle size Dn50 = 2.8 μm.

[0059] (3) The primary product includes large-particle primary products and small-particle primary products with a mass ratio of 4.00:1.00. The molar ratio n(primary product):n(Ti):n(Al) = 1.00:0.001:0.001 is used to weigh the primary product, titanium oxide, and aluminum oxide, mix them evenly, sinter at 900℃ for 10h, and then crush them to obtain the first layered metal oxide with the chemical formula LiCo. 0.9266 Mg 0.0046 Ti 0.001 Al 0.0678 O2, corresponding to a particle size Dn50=8.5μm.

[0060] (4) Prepare a cobalt chloride solution with a concentration of 1 mol / L, a sodium hydroxide solution with a concentration of 1 mol / L, and an ammonia solution with a concentration of 6 mol / L. Add the cobalt chloride solution, sodium hydroxide solution, and ammonia solution to the reaction equipment in a flow ratio of 1.00:1.45:0.55 according to the volume flow rate. Adjust the pH of the reaction system to 10.8 and stir for 2 hours. Then lower the pH to 8 and continue the reaction for 4 hours. The temperature of the reaction solution is 55℃. Nitrogen gas is introduced for protection. The solid-liquid ratio in the reaction vessel is 1:3. Continue the reaction for 50 hours to obtain a slurry of cobalt hydroxide. After washing and aging, cobalt hydroxide with uniform particle size is obtained. After calcination at 500℃ and sieving, cobalt tetroxide with Dn50=3.6μm is obtained.

[0061] (5) Weigh out sodium carbonate, cobalt tetroxide (Dn50=3.6μm), nickel oxide, and aluminum oxide in a molar ratio of n(Na):n(Co):n(Zr):n(Al)=0.76:1.00:0.020:0.050, mix them evenly, and keep them at 750℃ for 20h to obtain the transition sodium-electric material Na. 0.75 Co 0.9259 Zr 0.0278 Al 0.0467 O2; A transition sodium-ion battery material was mixed with lithium chloride and lithium nitrate, with a sodium:lithium chloride:lithium nitrate molar ratio of 1:2:6. Ion exchange was performed at 85℃ and pH=9.2 for 2 hours. After ion exchange, the system was washed and dried at 100℃ for 10 hours to obtain a second-layered metal oxide, LiCo. 0.9259 Zr 0.0278 Al 0.0463 O2 corresponds to Dn50=3.6μm.

[0062] (6) The first layered metal oxide and the second layered metal oxide were mixed uniformly at a mass ratio of 18:1, a rotation speed of 1000 r / min, and a time of 30 min to obtain a metal oxide material with the chemical formula 0.947 LiCo. 0.9266 Mg 0.0046 Ti0.001 Al 0.0678 O2·0.053 LiCo 0.9259 Zr 0.0278 Al 0.0463 O2. Corresponding particle size Dn50 = 8.2 μm.

[0063] Example 3 This embodiment provides a method for preparing a metal oxide material, including the following steps: (1) With a molar ratio of n(Li):n(Ni):n(Co):n(Mn):n(Ti):n(W) = 1.06:0.60:0.20:0.20:0.005:0.071, lithium carbonate, NCM622 precursor, titanium oxide, and tungsten oxide were weighed and uniformly mixed. The mixture was sintered at 850℃ for 10 h, and then crushed to obtain a primary product with the chemical formula LiNi. 0.5769 Co 0.1923 Mn 0.1923 Ti 0.0096 W 0.0289 O2. Corresponding particle size Dn50 = 3.2 μm.

[0064] (2) Weigh out the primary product, titanium dioxide, and aluminum oxide in a molar ratio of n(primary product):n(Ti):n(Al) = 1.00:0.001:0.001, mix them evenly, sinter at 900℃ for 10h, and then crush them to obtain the first layered metal oxide with the chemical formula LiNi. 0.5758 Co 0.1919 Mn 0.1919 Ti 0.0106 Al 0.0010 W 0.0288 O2, corresponding to a particle size Dn50=3.5μm.

[0065] (3) Prepare a cobalt sulfate solution with a concentration of 1 mol / L, a sodium hydroxide solution with a concentration of 1 mol / L, and an ammonia solution with a concentration of 5 mol / L. Add the cobalt chloride solution, sodium hydroxide solution, and ammonia solution to the reaction equipment in a flow ratio of 1.00:1.50:0.50 according to the volume flow rate. Adjust the pH of the reaction system to 11 and stir for 2 hours. Then lower the pH to 8 and continue the reaction for 4 hours. The temperature of the reaction solution is 50℃. The solid-liquid ratio in the reaction vessel is 1:5. Continue the reaction for 30 hours to obtain a slurry of cobalt hydroxide. After washing, aging, drying, and sieving, calcine at 500℃ and sieve again to obtain cobalt tetroxide with Dn50=3.6μm.

[0066] (4) Weigh out sodium carbonate, cobalt tetroxide (Dn50=3.6μm), and aluminum oxide in a molar ratio of n(Na):n(Co):n(Al) = 0.78:1.00:0.050, mix them evenly, and keep the mixture at 800℃ for 15 hours to obtain transition sodium electrical material powder Na. 0.75 Co 0.952 Al 0.048 O2; A transition sodium-ion battery powder was mixed with lithium chloride and lithium nitrate, with a sodium:lithium chloride:lithium nitrate molar ratio of 1:2:6. Ion exchange was performed at 160℃ and pH=9.0 for 2 hours. After ion exchange, the system was washed and dried at 100℃ for 10 hours to obtain a second-layer metal oxide, LiCo. 0.9524 Al 0.0476 O2, particle size Dn50=2.8μm.

[0067] (5) The first layered metal oxide and the second layered metal oxide were mixed uniformly at a mass ratio of 16:1, a rotation speed of 1200 r / min, and a time of 30 min to obtain a metal oxide material with the chemical formula 0.941 LiNi. 0.5758 Co 0.1919 Mn 0.1919 Ti 0.0106 Al 0.0010 W 0.0288 O2·0.059 LiCo 0.9524 Al 0.0476 O2. Corresponding particle size Dn50 = 3.1 μm.

[0068] Example 4 This embodiment provides a method for preparing a metal oxide material. The main difference from Embodiment 1 is that in step (1), the doping element is n(Mg):n(Al):n(Y) = 0.005:0.061:0.01; in step (5), n(Na):n(Co):n(Y):n(Al) = 0.76:1.00:0.020:0.05, and the chemical formula is 0.95LiCo. 0.9275 Mg 0.0046 Y 0.0093 Ti 0.001 Al 0.0576 O2·0.05LiCo 0.9346 Y 0.0187 Al 0.0467 O2. Corresponds to Dn50=10.3μm.

[0069] Example 5 This embodiment provides a method for preparing a metal oxide material. The main difference from Example 1 is that the mass ratio of large particle primary product to small particle primary product in step (3) is 3.8:1.2.

[0070] Example 6 This embodiment provides a method for preparing a metal oxide material. The main difference from Embodiment 1 is that the isothermal time in step (4) is 850°C for 15 hours.

[0071] Example 7 This embodiment provides a method for preparing a metal oxide material. The main difference from Embodiment 1 is that after ion exchange in step (5), the drying temperature is 200°C and the drying time is 15h.

[0072] Example 8 This embodiment provides a method for preparing a metal oxide material. The main difference from Embodiment 1 is that the ion exchange temperature in step (5) is 250°C and the time is 10h.

[0073] Example 9 This embodiment provides a method for preparing a metal oxide material. The main difference from Embodiment 2 is that the ion exchange temperature in step (5) is 220°C.

[0074] Comparative Example 1 This comparative example provides a method for preparing a first layered metal oxide, the main difference from Example 1 is that steps (4)-(6) are omitted.

[0075] Comparative Example 2 This comparative example provides a method for preparing a second layered metal oxide, the main difference from Example 1 being that steps (1)-(3) and (6) are omitted.

[0076] Comparative Example 3 This embodiment provides a method for preparing a metal oxide material. The main difference from Embodiment 1 is that the pH of the ion exchange is adjusted and Ni is not doped. The method includes the following steps: (1)-(4) Same as Example 1.

[0077] (5) Weigh out sodium carbonate, cobalt tetroxide (Dn50=3.6μm), and aluminum oxide in a molar ratio of n(Na):n(Co):n(Al) = 0.76:1.00:0.050, mix them evenly, and keep the mixture at 750℃ for 20h to obtain transition sodium electrical material powder Na. 0.75 Co 0.9523 Al 0.0476O2; A transition sodium-ion battery material powder was mixed with lithium chloride and lithium nitrate, with a sodium:lithium chloride:lithium nitrate molar ratio of 1:2:6. Ion exchange was performed at 85°C and pH 11.5 for 2 hours. After ion exchange, the system was washed and dried at 100°C for 10 hours to obtain the new structural material B, LiCo. 0.9523 Al 0.0476 O2, corresponding to Dn50=3.2μm, XRD pattern as follows Figure 2 As shown, the SEM image is as follows: Figure 4 As shown.

[0078] (6) The first layered metal oxide and the second layered metal oxide are mixed uniformly at a mass ratio of 19:1, a rotation speed of 1000 r / min, and a time of 30 min to obtain a mixed oxide powder with the chemical formula 0.95 LiCo. 0.9275 Zr 0.0046 Ti 0.001 Al 0.0669 O2·0.05 LiCo 0.9523 Al 0.0476 O2 corresponds to Dn50=10.3μm.

[0079] Comparative Example 4 This embodiment provides a method for preparing a metal oxide material, the main difference from Example 1 being the adjustment of the drying temperature after ion exchange, including the following steps: (1)-(4) Same as Example 1 (5) Weigh out sodium carbonate, cobalt tetroxide (Dn50=3.6μm), nickel oxide, and aluminum oxide in a molar ratio of n(Na):n(Co):n(Ni):n(Al) = 0.76:1.00:0.020:0.050, mix them uniformly, and keep them at 750℃ for 20h to obtain the transition sodium-electric material Na. 0.75 Co 0.9346 Ni 0.0187 Al 0.0467 O2; A transition sodium-ion battery material was mixed with lithium chloride and lithium nitrate, with a sodium:lithium chloride:lithium nitrate molar ratio of 1:2:6. Ion exchange was performed at 85℃ and pH=9.5 for 2 hours. After ion exchange, the system was washed and dried at 350℃ for 10 hours to obtain a second-layer metal oxide, LiCo. 0.9346 Ni 0.0187 Al 0.0467 O2 corresponds to Dn50=3.2μm.

[0080] (6) Same as Example 1.

[0081] Comparative Example 5 This embodiment provides a method for preparing a metal oxide material. The main difference from Embodiment 3 is that steps (3)-(5) are omitted.

[0082] Comparative Example 6 This embodiment provides a method for preparing a metal oxide material. The main difference from Embodiment 3 is that the drying temperature after ion exchange is adjusted, and the method includes the following steps: (1)-(3) Same as Example 3.

[0083] (4) Weigh out sodium carbonate, cobalt tetroxide (Dn50=3.6μm), and aluminum oxide in a molar ratio of n(Na):n(Co):n(Al) = 0.78:1.00:0.050, mix them evenly, and keep the mixture at 800℃ for 15 hours to obtain transition sodium electrical material powder Na. 0.75 Co 0.952 Al 0.048 O2; A transition sodium-ion battery powder was mixed with lithium chloride and lithium nitrate, with a sodium:lithium chloride:lithium nitrate molar ratio of 1:2:6. Ion exchange was performed at 160℃ and pH=9.0 for 2 hours. After ion exchange, the system was washed and dried at 500℃ for 10 hours to obtain a second-layer metal oxide, LiCo. 0.9524 Al 0.0476 O2, particle size Dn50=2.8μm.

[0084] (5) Same as Example 3.

[0085] Comparative Example 7 This embodiment provides a method for preparing a metal oxide material. The main difference from Embodiment 1 is that the ratio of the first layered metal oxide and the second layered metal oxide is adjusted, including the following steps: (1)-(5) Same as Example 1.

[0086] (6) The first layered metal oxide and the second layered metal oxide were mixed uniformly at a mass ratio of 5:1, a rotation speed of 1000 r / min, and a time of 30 min to obtain a metal oxide material with the chemical formula 0.83 LiCo. 0.9275 Zr 0.0046 Ti 0.001 Al 0.0669 O2·0.17 LiCo 0.9346 Ni 0.0187 Al 0.0467 O2 corresponds to Dn50=10.3μm.

[0087] Comparative Example 8 This embodiment provides a method for preparing a metal oxide material. The main difference from Embodiment 1 is that the pH of the ion exchange in step (5) is adjusted to 11.5.

[0088] Comparative Example 9 This embodiment provides a method for preparing a metal oxide material. The main difference from Embodiment 1 is that step (5) is free of Ni element doping.

[0089] Comparative Example 10 This embodiment provides a method for preparing a metal oxide material. The main difference from Embodiment 1 is that step (5) does not involve Zr doping.

[0090] The materials prepared in the above embodiments and comparative examples were tested, and the specific test methods are as follows: (1) Electrochemical performance testing: A. Electrode preparation: 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 the 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. Water is added, and the mixture is stirred to form a slurry. This slurry is then coated onto copper foil and dried at 80°C to form the negative electrode sheet. B. Pouch Battery Assembly: Assemble the positive electrode, negative electrode, electrolyte and separator into a pouch battery. C. Capacity Test (25℃, 0.2C): At room temperature (25℃), charge at a constant current rate of 0.2C to V2 voltage, then further charge at a constant voltage of V2 until the current drops below 0.05C, bringing it to a fully charged state at V2. Then discharge at a constant current rate of 0.2C to V1 to obtain the discharge capacity. The discharge specific capacity at 0.2C / 0.2C or other rates is obtained using the following formula: Discharge specific capacity = Discharge capacity / Mass of cathode material. For rate testing, first test at 0.2C for 2 cycles, then at 2.0C for 3 cycles, then at 0.2C for 2 cycles; then at 2.0C for 3 cycles. The average capacity of the three cycles is taken as the 2.0C rate capacity.

[0091] The V1 of LCO cathode materials is 3.0V and the V2 is 4.55V, while the V1 of lithium nickel cobalt manganese oxide (Ni:Co:Mn=6:2:2) cathode materials is 2.8V and the V2 is 4.4V.

[0092] D. Capacity retention test (45℃, 1.0C): The cycle capacity retention performance of the cathode material is evaluated by the number of cycles in which the capacity drops to 80%. One cycle includes: the battery under test is left to stand for 120 minutes, then charged at a constant current of 1C to V2, then charged at a constant voltage of V2 to 0.05C, left to stand for 5 minutes, and then discharged at a constant current of 1C to V1. The discharge capacity is recorded. Repeat the above steps until the battery capacity drops to 80%, and record the number of cycles; the battery capacity dropping to 80% means that the discharge capacity after 20n cycles is 80% of the discharge capacity in the first cycle.

[0093] The V1 of LCO cathode materials is 3.0V and the V2 is 4.53V, while the V1 of lithium nickel cobalt manganese oxide (Ni:Co:Mn=6:2:2) cathode materials is 2.8V and the V2 is 4.4V.

[0094] (2) Powder and compaction test A. Electrode Compaction Density: 1) After coating and drying, the electrode is rolled under 300T (tons) pressure. The thickness is measured at 10 points using a micrometer, and the average thickness is taken. Coating thickness = average thickness - aluminum foil thickness (aluminum foil thickness is fixed); 2) Coating area: Test the surface area of ​​the electrode coating; Coating volume = coating thickness * coating area; 3) Weigh the mass using an electronic balance. Coating mass = total mass of the coated electrode - aluminum foil mass; Electrode compaction density = coating mass / coating volume = coating mass / (coating thickness * coating area).

[0095] B. In the split double peaks that exist between 2θ=18°-20°, the ratio of the peak height intensity of the lower angle peak to that of the higher angle peak is n.

[0096] C. Percentage of Agglomerated Particles: Using SEM images magnified 1000x, all identifiable particles within the field of view were counted. Agglomerated particles were defined as "particles formed by the aggregation of 3 or more individual small particles," while independent particles without aggregation were defined as non-agglomerated particles. The percentage of agglomerated particles was calculated using the following formula, counting both agglomerated and total particles: The percentage of aggregated particles = (number of aggregated particles ÷ total number of particles) × 100%.

[0097] The results of the above tests are shown in Tables 1 and 2, where Table 1 shows the test results of LCO cathode materials and Table 2 shows the test results of lithium nickel cobalt manganese oxide cathode materials. Table 1

[0098] As shown in Table 1, for Examples 1, 2, and 4-8, the capacity, cycle retention rate, and powder compaction density were relatively close after fine-tuning the doping elements of the first and second layered metal oxides, the ion exchange time, temperature, and gradation ratio. However, a comparison between Examples 1 and Examples 9-12 shows that adjustments to the ion exchange temperature, pH value, and doping elements outside the preferred range would affect the structure and morphology of the second layered metal oxide, leading to performance degradation. Comparing Example 1 with Comparative Example 1, it can be seen that Comparative Example 1 lacks the second layered metal oxide, resulting in deteriorated capacity and rate performance. Comparing Example 1 with Comparative Example 2, it can be seen that the second layered metal oxide alone has a higher capacity and rate, but the compaction density is low, affecting the overall energy density. Comparing Example 1 with Comparative Example 3, it can be seen that Comparative Example 3 did not add Ni element or adjust pH, resulting in obvious flake-like second layered metal oxide powder, and the compaction density of the obtained metal oxide material decreased, with I3 > I2 in the XRD pattern of the second layered metal oxide. Comparing Example 1 with Comparative Example 4, it can be seen that in Example 4, the drying temperature in step 5 is 350℃, and the second layered metal oxide powder transforms into the first layered metal oxide at a higher temperature, causing the capacity of Comparative Example 4 to deteriorate. Compared with Comparative Example 7, Example 1 shows that the compaction density of the second layered metal oxide with a gradation of 50% is significantly reduced. Compared with Comparative Examples 9 and 12, Example 1 shows that if the pH is not adjusted to the preferred range or element doping is not performed during the synthesis of the second layered metal oxide, it will lead to the production of sheet-like particles or the formation of sheet-like structures, affecting the capacity and compaction density.

[0099] Table 2

[0100] As shown in Table 2, comparing Example 3 with Comparative Example 5, Comparative Example 5 uses first layered metal oxide powder, which is not mixed with second layered metal oxide powder, resulting in deterioration of capacity and cycle life. Comparing Example 3 with Comparative Example 6, Comparative Example 6 has a sintering temperature of 500°C in step 3. At this temperature, the second layered metal oxide transforms into the first layered metal oxide. Comparative Example 6 uses a combination of two different first layered metal oxides, which leads to deterioration of capacity and cycle life.

[0101] 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 701515 (Ni:Co:Mn=70:15:15), ternary 811, and ternary 9055 (Ni:Co:Mn=90:5:5), etc., and can cover LNO, LCO, and other layered structures, etc. 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 metal oxide material, characterized in that, Including first layered metal oxides and second layered metal oxides; In the XRD pattern of the first layered metal oxide, characteristic peaks exist at 2θ of 18.85°-19.05°, 37.0°-37.8°, and 45°-46°, respectively; The XRD pattern of the second layered metal oxide satisfies I1>I2>I3, where I1 is the peak intensity of the characteristic peak at 2θ=18.4°-18.7°, I2 is the peak intensity of the characteristic peak at 2θ=38°-38.6°, and I3 is the peak intensity of the characteristic peak at 2θ=46.8°-47.6°.

2. The metal oxide material according to claim 1, characterized in that, In the XRD pattern of the metal oxide material, there is a set of characteristic split double peaks between 2θ = 18° and 20°. The ratio of the peak height intensity of the low-angle peak to the high-angle peak in the split double peak is n, and satisfies 0.05 ≤ n ≤ 0.

25. And / or, the ratio of the peak height intensity of I2 and I3 is 1-3.

5.

3. The metal oxide material according to claim 1, characterized in that, The proportion of agglomerated particles in the metal oxide material is less than 10%; And / or, the mass ratio of the second layered metal oxide to the total mass of the first and second layered metal oxides is less than 10%.

4. The metal oxide material according to claim 1, characterized in that, The first layered metal oxide Dn50 has a thickness of 1.5 μm to 12 μm; And / or, the Dn50 of the second layered metal oxide is 1.0 μm ~ 9.0 μm; And / or, the ratio of Dn50 of the first layered metal oxide to the second layered metal oxide is 2.0-5.

5.

5. The metal oxide material according to claim 1, characterized in that, The chemical formula of the metal oxide material is (1 - x)Li a M 1-b M′ b O2·xLi c M 1-d M′′ d O2, where 0 < x ≤ 0.1, 0.98 ≤ a ≤ 1.03, 0 < b ≤ 0.1, 0.98 ≤ c ≤ 1.03, 0 < d ≤ 0.1, M includes at least one of Ni, Co, and Mn, M′ includes at least one of Ba, La, Ti, Zr, V, Nb, Cu, Mg, B, Sr, Al, Sc, Y, Ga, Zn, W, Mo, Si, Sb, Ta, and Ca, and M′′ includes at least one of Ba, La, Ti, Zr, V, Nb, Cu, Mg, B, Sr, Al, Sc, Y, Ga, Zn, W, Mo, Si, Sb, Ta, and Ca; And / or, the chemical formula of the first layered metal oxide is Li a M 1-b M′ b O2, where 0.98 ≤ a ≤ 1.03, 0 < b ≤ 0.1, M includes at least one of Ni, Co, and Mn, and M′ includes at least one of Ba, La, Ti, Zr, V, Nb, Cu, Mg, B, Sr, Al, Sc, Y, Ga, Zn, W, Mo, Si, Sb, Ta, and Ca; And / or, the chemical formula of the second-layered metal oxide is Li c M 1-d M′′ d O2, where 0.98 ≤ c ≤ 1.03, 0 < d ≤ 0.1, M includes at least one of Ni, Co, and Mn, and M′′ includes at least one of Ba, La, Ti, Zr, V, Nb, Cu, Mg, B, Sr, Al, Sc, Y, Ga, Zn, W, Mo, Si, Sb, Ta, and Ca.

6. A method for preparing the metal oxide material according to claim 1, characterized in that, include: The first layered metal oxide and the second layered metal oxide are mixed to obtain the metal oxide material.

7. The method for preparing the metal oxide material according to claim 6, characterized in that, The mixing speed is 300 r / min to 1500 r / min, and the time is 10 min to 240 min.

8. The method for preparing the metal oxide material according to claim 1, characterized in that, The preparation of the first layered metal oxide includes: mixing a lithium source, large-particle M source and M′ source, calcining and crushing to obtain a large-particle primary product; mixing a lithium source, small-particle M source and M′ source, calcining and crushing to obtain a small-particle primary product; mixing the large-particle primary product and the small-particle primary product, sintering and pulverizing to obtain the first layered metal oxide. And / or, the preparation of the second layered metal oxide includes: mixing a sodium source, an M source and an M′′ source and then sequentially calcining, crushing, molten salt ion exchange, washing and drying to obtain the second layered metal oxide.

9. The method for preparing the metal oxide material according to claim 8, characterized in that, In the preparation process of the first layered metal oxide, the calcination temperature is 800℃~1200℃ and the holding time is 5h~15h; The large-particle primary product has a Dn50 of 8μm~14μm, and the small-particle primary product has a Dn50 of 2μm~7μm. The mass ratio of the large-particle primary product to the small-particle primary product is (2.5-4.5):

1. And / or, the sintering temperature is 800℃-1000℃, and the holding time is 8h-12h; And / or, in the preparation process of the second layered metal oxide, the calcination temperature is 400℃~900℃ and the holding time is 5h~25h; And / or, the molten salt ion exchange step includes: mixing the intermediate product obtained by calcination and crushing during the preparation of the second layered metal oxide with lithium salt and performing molten salt ion exchange, wherein the molar ratio of lithium element in lithium salt to sodium element in intermediate product is (30 ~ 5):

1. And / or, the temperature for molten salt ion exchange is 60~180℃, the pH is 8.0~10.5, and the time is 2h~25h; And / or, the drying temperature is 100℃-200℃, and the time is 10h-15h.

10. A battery, characterized in that, Includes the metal oxide material as described in any one of claims 1-5.

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