A lithium-rich manganese-based material and applications

Abstract

The embodiment of the present application provides a lithium-rich manganese-based material and application. The lithium-rich manganese-based material comprises a lithium-rich manganese-based matrix and a coating layer on at least part of the surface of the lithium-rich manganese-based matrix; the lithium-rich manganese-based matrix comprises (Li2MnO3) x (LiNi a Co b Mn c M1 d M2 e L f O2) y , 0.05<=a<=0.7, 0<=b<=0.6, 0.01<=c<=0.8, 0 The coating layer comprises a carbon-nitrogen layer and a plurality of protruding structures on at least part of the surface of the carbon-nitrogen layer away from the lithium-rich manganese-based matrix, and the protruding structures comprise a solid-state electrolyte. The positive lithium-rich manganese-based material has high capacity, long cycle life and excellent interface compatibility.

Description

Technical Field

[0001] This application relates to the field of electrochemical technology, and in particular to a lithium-rich manganese-based material and its applications. Background Technology

[0002] Lithium-ion batteries, as the core of high-energy-density energy storage technology, have been widely applied to key areas such as consumer electronics, new energy vehicles, and large-scale energy storage systems. For example, in the electric vehicle sector, user demand for longer driving range has driven battery system energy density to exceed 300Wh / kg, while traditional ternary materials (such as NCM811) and lithium iron phosphate materials are unable to meet higher requirements due to capacity limitations and cost issues. In energy storage systems, low-cost, long-life electrochemical energy storage technology has become the core direction for replacing pumped hydro storage, and there is an urgent need for cathode materials with high specific capacity and scalable production capabilities.

[0003] Lithium-rich manganese-based oxides are considered the preferred material for next-generation lithium-ion batteries due to their theoretical specific capacity exceeding 300 mAh / g and the fact that they are primarily made of manganese (eliminating the need for expensive nickel and cobalt). However, their industrial application is hampered by bottlenecks such as poor cycle stability and interfacial side reactions, severely limiting their large-scale use in power batteries and energy storage systems.

[0004] Therefore, developing a lithium-rich manganese-based material that combines high capacity, long cycle life, and excellent interface compatibility is a key path to promote breakthroughs in high-energy-density lithium-ion battery technology. Summary of the Invention

[0005] This application provides a lithium-rich manganese-based material that combines high capacity, long cycle life, and excellent interface compatibility.

[0006] This application provides a lithium-rich manganese-based material, wherein the lithium-rich manganese-based material includes a lithium-rich manganese-based matrix and a coating layer located on at least a portion of the surface of the lithium-rich manganese-based matrix;

[0007] The lithium-rich manganese-based matrix includes the compound shown in Formula 1;

[0008] (Li2MnO3) x (LiNi a Co b Mn c M1 d M2 e L f O2) y Formula 1

[0009] In Equation 1, 0.05≤a≤0.7, 0<b≤0.6, 0.01≤c≤0.8, 0<d≤0.1, 0<e≤0.1, 0<f≤0.05, 0<x<1, 0<y<1;

[0010] M1 includes Al and / or Mg, M2 includes at least one element selected from Zr, Nb, Ru, V, Ta, Mo, W, Ti, Cr, and L includes halogens;

[0011] The coating layer includes a carbon-nitrogen layer and a plurality of protrusions located on at least a portion of the surface of the carbon-nitrogen layer away from the lithium-rich manganese substrate, the protrusions including a solid electrolyte.

[0012] The lithium-rich manganese-based material as described above, wherein the lithium-rich manganese-based matrix includes a central core layer, a high-entropy layer, and an oxygen hole layer; the high-entropy layer is located on at least a portion of the surface of the central core layer, and the oxygen hole layer is located on at least a portion of the surface of the high-entropy layer away from the central core layer;

[0013] The oxygen hole layer includes halogens; the high-entropy layer includes at least three of M2, Co, Ni, and Mn, and the high-entropy layer includes at least M2;

[0014] Preferably, the oxygen cavitation layer includes F;

[0015] Preferably, the ratio of the thickness of the high-entropy layer, the thickness of the oxygen hole layer, to the diameter of the lithium-rich manganese substrate is 1:(0.01-0.5):(5-200).

[0016] Preferably, the thickness of the high-entropy layer is 5nm-30nm; and / or, the thickness of the oxygen hole layer is 0.15nm-2.5nm.

[0017] The lithium-rich manganese-based material as described above, wherein the C content is 200ppm-1000ppm; and / or, the N content is 500ppm-1500ppm; and / or, the L content is 100ppm-300ppm; and / or, the Mg content is 400ppm-700ppm; and / or, the Al content is 500ppm-800ppm.

[0018] Preferably, M1 is uniformly distributed in the lithium-rich manganese matrix;

[0019] Preferably, M1 includes Mg and Al.

[0020] In the lithium-rich manganese-based material described above, the ratio of the diameter of the lithium-rich manganese-based substrate to the thickness of the carbon-nitrogen layer is (10-500):1;

[0021] Preferably, the lithium-rich manganese-based material comprises primary particles with an average particle size of 0.1 μm-0.7 μm; and / or, the lithium-rich manganese-based matrix has an average diameter of 0.1 μm-0.7 μm; and / or, the carbon-nitrogen layer has a thickness of 1 nm-10 nm.

[0022] In the lithium-rich manganese-based material described above, the area coverage of the protrusion structure is 10%-50%; and / or,

[0023] The solid electrolyte comprises at least one of lithium aluminum titanium phosphate, lithium lanthanum zirconium oxide, lithium aluminum silicon titanium phosphate, lithium lanthanum titanium oxide, and lithium lanthanum zirconium tantalum oxide; preferably, the solid electrolyte comprises lithium aluminum titanium phosphate; and / or,

[0024] The width of the protrusion structure is 0.5nm-3nm; and / or,

[0025] The maximum height of the protrusion structure is 1nm-30nm; and / or,

[0026] The spacing D between two adjacent protrusions satisfies: 0 < D ≤ 300 nm.

[0027] The lithium-rich manganese-based material as described above, wherein the span of the secondary particles of the lithium-rich manganese-based material is 0.8-1.5; and / or,

[0028] The secondary particles of the lithium-rich manganese-based material have a Dv50 of 1μm-5μm; preferably, the secondary particles of the lithium-rich manganese-based material have a Dv50 of 3μm-4μm.

[0029] The lithium-rich manganese-based material described above has a specific surface area of ​​1 m². 2 / g-4m 2 / g; and / or,

[0030] The powder conductivity of the lithium-rich manganese-based material is ≥1. 10 -7 S / cm; and / or,

[0031] The surface LiOH content of the lithium-rich manganese-based material is <500ppm; and / or,

[0032] The surface Li2CO3 content of the lithium-rich manganese-based material is <800ppm.

[0033] The lithium-rich manganese-based material as described above, wherein the X-ray diffraction pattern of the lithium-rich manganese-based material has a characteristic peak of the (003) plane with a 2θ of 18.4°-18.5°, and a characteristic peak of the (003) plane with a 2θ of 26.7°-27.1°; and / or,

[0034] The X-ray diffraction pattern of the lithium-rich manganese-based material exhibits a characteristic peak with a 2θ value of 29.3°–29.6°; and / or,

[0035] In the X-ray diffraction pattern of the lithium-rich manganese-based material, the full width at half maximum (FWHM) of the characteristic peak on the (003) plane is 0.13-0.149; and / or,

[0036] In the X-ray diffraction pattern of the lithium-rich manganese-based material, the intensity I of the characteristic peak of the (003) surface is... （003） The intensity I of the characteristic peak of the (104) surface （104） The ratio of I （003） / I （104） It is 1.78-1.9.

[0037] This application also provides a lithium-ion secondary battery, including a positive electrode sheet, the positive electrode sheet including a positive current collector and a positive active layer disposed on at least one side surface of the positive current collector in the thickness direction, the positive active layer including a positive active material, wherein the positive active material includes a lithium-rich manganese-based material as described above.

[0038] The lithium-ion secondary battery described above includes any one of all-solid-state batteries, semi-solid-state batteries, and liquid batteries.

[0039] This application uses a lithium-rich manganese-based compound containing a specific composition as a lithium-rich manganese-based matrix, and provides a coating layer including a carbon-nitrogen layer and a protruding structure containing a solid electrolyte located on at least a portion of the surface of the lithium-rich manganese-based matrix. This can synergistically improve the structural stability of the lithium-rich manganese-based matrix and the interfacial stability of the particle surface, suppress oxygen release, phase structure evolution and interfacial side reactions during charging and discharging, thereby reducing voltage decay and interfacial impedance growth, and improving the capacity retention, cycle life and application reliability of the lithium-rich manganese-based material. Attached Figure Description

[0040] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0041] Figure 1 This is a schematic diagram of the structure of the lithium-rich manganese-based material in some embodiments of this application;

[0042] Figure 2 The XRD patterns are of lithium-rich manganese-based materials in Example 1 and Comparative Examples 1-4.

[0043] Figure 3 This is a SEM image of the lithium-rich manganese-based material of Example 1 at a certain magnification.

[0044] Figure 4 SEM image of the lithium-rich manganese-based material in Comparative Example 1;

[0045] Figure 5 SEM image of the lithium-rich manganese-based material in Comparative Example 2;

[0046] Figure 6 SEM image of the lithium-rich manganese-based material in Comparative Example 3;

[0047] Figure 7 SEM image of the lithium-rich manganese-based material in Comparative Example 4;

[0048] Figure 8 This is a SEM image of the lithium-rich manganese-based material of Example 1 at another magnification.

[0049] Figure 9 for Figure 8 Distribution diagram of Ni element in lithium-rich manganese-based materials;

[0050] Figure 10 for Figure 8 Distribution diagram of Mn element in lithium-rich manganese-based materials;

[0051] Figure 11 for Figure 8 Distribution diagram of Co element in lithium-rich manganese-based materials;

[0052] Figure 12 for Figure 8 Distribution diagram of Al element in lithium-rich manganese-based materials;

[0053] Figure 13 for Figure 8 Distribution diagram of Mg element in lithium-rich manganese-based materials;

[0054] Figure 14 for Figure 8 Distribution diagram of Ti element in lithium-rich manganese-based materials;

[0055] Figure 15 for Figure 8 Distribution diagram of W element in lithium-rich manganese-based materials;

[0056] Figure 16 for Figure 8 Distribution diagram of F element in lithium-rich manganese-based materials;

[0057] Figure 17 Discharge curves of all-solid-state batteries using lithium-rich manganese-based materials, including Example 1 and Comparative Examples 1-4;

[0058] Figure 18 The discharge curves are of liquid lithium-ion batteries containing lithium-rich manganese-based materials, including Example 1 and Comparative Examples 1-4.

[0059] Explanation of reference numerals in the attached figures:

[0060] 11: Central core layer;

[0061] 12: High-entropy layer;

[0062] 13: Oxygen cavity layer;

[0063] 21: Carbon-nitrogen layer;

[0064] 22: Protruding structure. Detailed Implementation

[0065] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0066] Existing cathode materials struggle to simultaneously achieve both bulk material stability and interfacial transport requirements. Particularly under high-voltage charge-discharge conditions, lithium-rich manganese-based materials are prone to problems such as excessively high lattice oxygen activity, accelerated oxygen release, and the evolution of layered structures into spinel or rock salt phases, leading to a decrease in average discharge voltage and continuous capacity decay. Especially in solid-state battery systems, the contact between the cathode particle surface and the solid electrolyte is often limited by insufficient interfacial adhesion and inadequate chemical compatibility, resulting in increased contact resistance. In liquid systems, surface side reactions and transition metal dissolution further destabilize the interface. Therefore, how to simultaneously suppress voltage decay, mitigate structural degradation during cycling, and reduce interfacial resistance while ensuring the fabrication feasibility and particle structure stability of lithium-rich manganese-based materials has become a pressing technical challenge.

[0067] To address the aforementioned technical issues, this application proposes a lithium-rich manganese-based material that synergistically designs the composition of the lithium-rich manganese-based matrix and the surface interface structure of the particles. This enables the material to balance bulk stability, surface protection, and interface compatibility in actual battery systems, providing a foundation for achieving high-capacity, low-impedance, and long-life battery performance.

[0068] Figure 1 This is a schematic diagram of the structure of the lithium-rich manganese-based material in some embodiments of this application. For example... Figure 1 As shown, this application provides a lithium-rich manganese-based material, which includes a lithium-rich manganese-based matrix and a coating layer located on at least a portion of the surface of the lithium-rich manganese-based matrix.

[0069] The lithium-rich manganese-based matrix includes the compounds shown in Formula 1;

[0070] (Li2MnO3) x (LiNi a Co b Mn c M1 d M2 e L f O2) y Formula 1

[0071] In Equation 1, 0.05≤a≤0.7, 0<b≤0.6, 0.01≤c≤0.8, 0<d≤0.1, 0<e≤0.1, 0<f≤0.05, 0<x<1, 0<y<1;

[0072] M1 includes Al and / or Mg, M2 includes at least one element selected from Zr, Nb, Ru, V, Ta, Mo, W, Ti, Cr, and L includes halogens;

[0073] The coating layer includes a carbon-nitrogen layer 21 and a plurality of protrusions 22 located on at least a portion of the surface of the carbon-nitrogen layer 21 away from the lithium-rich manganese substrate, the protrusions 22 including a solid electrolyte.

[0074] In this application, the coating layer can be located on a portion of the surface of the lithium-rich manganese-based substrate, or it can be located on the entire surface of the lithium-rich manganese-based substrate. The protrusion structure 22 in this application can be an island-like, granular, dot-like, nano-protrusion-like, semi-continuous lattice-like, or locally interconnected structure; it is not required to form a completely continuous dense film on the entire surface. In the coating layer, the protrusion structure 22 can be located on the entire surface of the carbonitriding layer 21 away from the lithium-rich manganese-based substrate, or it can be located on a portion of the surface of the carbonitriding layer 21 away from the lithium-rich manganese-based substrate. The lithium-rich manganese-based material of this application comprises, from the inside out, a lithium-rich manganese-based substrate, a carbonitriding layer 21, and the protrusion structure 22.

[0075] The lithium-rich manganese-based matrix includes a lithium-rich manganese phase (Li₂MnO₃) and a layered transition metal oxide phase (LiNi). a Co b Mn c M1 d M2 e L f O2). The synergistic effect of the lithium-rich manganese phase and the layered transition metal oxide phase can ensure the capacity and cycle performance of lithium-rich manganese-based materials. In the layered transition metal oxide phase of the lithium-rich manganese matrix, Mg is present in the M1 element. 2+ The ionic radius of Li + With radii similar to some transition metal ions, Al can be doped into the crystal lattice, stabilizing it without blocking channels, making it a capacity-friendly structure stabilizer. 3+The Al-O formed by doping has strong bond energy, which can enhance the skeletal stability and thermal stability of lithium-rich manganese-based materials. The L element (e.g., at least one of F, Cl, Br, and I) in the layered transition metal oxide phase of the lithium-rich manganese-based matrix can replace the O element, construct oxygen vacancies, enhance the diffusion kinetics of lithium ions, activate stable cation redox reactions, minimize irreversible oxygen release, and suppress voltage decay. The M2 element in the layered transition metal oxide phase of the lithium-rich manganese-based matrix can reduce charge transfer resistance, eliminate harmful strain caused by lattice contraction, improve conductivity, and improve the cycle performance of the battery.

[0076] The coating layer protects the lithium-rich manganese-based matrix, reducing the possibility of side reactions between the matrix and the electrolyte. The protrusion structure 22 increases the cross-sectional contact between the lithium-rich manganese-based material and the electrolyte. In the coating layer, the carbon-nitrogen layer 21 includes carbon and nitrogen elements, which improves the electronic conductivity of the lithium-rich manganese-based material. The protrusion structure 22 includes a solid electrolyte, which improves the ionic conductivity of the lithium-rich manganese-based material without affecting its capacity.

[0077] Therefore, this application significantly improves the structural stability and interfacial compatibility of lithium-rich manganese-based materials through the synergistic effect of the multilayer structure. M1, L, and M2 can synergistically improve the structural stability and electrochemical performance of lithium-rich manganese-based materials, achieving a comprehensive performance of high capacity and high cycle stability.

[0078] In some implementations, x + y = 1.

[0079] like Figure 1 As shown, in some embodiments of this application, the lithium-rich manganese-based substrate includes a central core layer 11, a high-entropy layer 12, and an oxygen hole layer 13; the high-entropy layer 12 is located on at least a portion of the surface of the central core layer 11, and the oxygen hole layer 13 is located on at least a portion of the surface of the high-entropy layer 12 away from the central core layer 11.

[0080] The oxygen hole layer 13 includes halogens; the high-entropy layer 12 includes at least three of M2, Co, Ni, and Mn, and the high-entropy layer 12 includes at least M2.

[0081] In this application, the high-entropy layer 12 can be located on the entire surface of the central core layer 11, or on a portion of the surface of the central core layer 11; the oxygen hole layer 13 can be located on the entire surface of the high-entropy layer 12 away from the central core layer 11, or it can be located on a portion of the surface of the high-entropy layer 12 away from the central core layer 11. That is, the lithium-rich manganese-based substrate includes, from the inside out, the central core layer 11, the high-entropy layer 12, and the oxygen hole layer 13.

[0082] Among them, halogens possess the characteristics of electricity price compensation, electronegativity pulling, and reduced vacancy formation energy, enabling the formation of oxygen hole layers13. Specifically, electricity price compensation is the most fundamental reason, L - Only 1 valence, while O 2- If it's divalent, and each L occupies an O site, there will be one less negative charge. To maintain charge balance, the O sites will automatically be lost. 2- To complete the valence state; in addition, L is an electronegative element, easily absorbing charge, making it easy for nearby O to detach. Therefore, halogens can replace O to form a nanoscale defect layer with a large number of missing oxygen atoms and dense vacancies in the lattice. This is an intrinsic defect layer formed after the bulk lattice of the material is controlled on the surface and oxygen is controllably removed. The oxygen hole layer 13 can enhance Li + Diffusion kinetics activate stable cation redox reactions and minimize irreversible oxygen release, thus suppressing voltage decay.

[0083] When the high-entropy layer 12 includes at least three of M2, Co, Ni, and Mn, and at least M2, the high-entropy layer 12 exhibits high structural stability, low Gibbs free energy, and excellent ion transport properties. It not only physically isolates the active material from the electrolyte, suppressing interfacial side reactions and transition metal dissolution, but also effectively anchors lattice oxygen, delays the structural evolution from layered to spinel or rock salt phases, and significantly reduces the voltage decay rate. Simultaneously, the synergistic effect of multiple metal elements in the high-entropy layer 12 optimizes the interfacial Li⁺ conduction and electron transport kinetics, improving the first coulombic efficiency and rate performance.

[0084] Furthermore, the oxygen hole layer 13 includes F, which is the most electronegative element and easily absorbs charges, making it easy for nearby O to fall off; F can significantly reduce the formation energy of oxygen vacancies, thus lowering the O falling off energy level.

[0085] In some embodiments of this application, when the ratio of the thickness of the high-entropy layer 12, the thickness of the oxygen-hole layer 13, to the diameter of the lithium-rich manganese substrate is 1:(0.01-0.5):(5-200), a sufficiently effective oxygen-hole layer 13 and a high-entropy layer 12 can be formed without significantly sacrificing the bulk capacity of the lithium-rich manganese substrate, thus fully utilizing the functions of the oxygen-hole layer 13 and the high-entropy layer 12. The high-entropy layer 12 and the oxygen-hole layer 13 synergistically construct a layered structure of "internal stability and external protection," enabling the central core layer 11 to continuously contribute high specific capacity, the high-entropy layer 12 to enhance structural stability, and the oxygen-hole layer 13 to improve surface chemical stability, thereby ensuring that the lithium-rich manganese substrate maintains capacity, rate performance, and interface stability under high voltage and long cycling conditions.

[0086] For example, the ratio of the thickness of the high-entropy layer 12, the thickness of the oxygen hole layer 13, to the diameter of the lithium-rich manganese substrate can be any one of 1:0.01:5, 1:0.01:100, 1:0.5:5, 1:0.5:100, 1:0.5:200, or any two of them.

[0087] Furthermore, when the thickness of the high-entropy layer 12 is 5nm-30nm, the thinner high-entropy layer 12 can achieve surface stabilization and ion diffusion regulation of the lithium-rich manganese substrate, avoid excessive thickness leading to transport obstruction, and improve the rate performance of the battery.

[0088] For example, the thickness of the high-entropy layer 12 can be any of 5nm, 10nm, 15nm, 20nm, 30nm, or any combination thereof.

[0089] Furthermore, when the thickness of the oxygen hole layer 13 is 0.15nm-2.5nm, the nanoscale oxygen hole layer can provide defect regulation and anti-oxidation release, without increasing interfacial impedance or occupying effective active volume due to excessive layer thickness.

[0090] For example, the thickness of the oxygen hole layer 13 can be any of 0.15 nm, 0.2 nm, 1 nm, 2 nm, 2.5 nm, or any combination thereof.

[0091] In this context, the thickness of the high-entropy layer 12 refers to its average thickness, the thickness of the oxygen-hole layer 13 is its average thickness, and the diameter of the lithium-rich manganese-based matrix is ​​its average particle size. In some embodiments, the cross-section of the lithium-rich manganese-based material can be subjected to SEM-EDS testing, where the thickness of the L element distribution is the thickness of the oxygen-hole layer 13, the thickness of the M2 element distribution is the thickness of the high-entropy layer 12, and the remainder is the central core layer 11.

[0092] In some embodiments of this application, M1 is uniformly distributed within a lithium-rich manganese-based matrix. M1 serves as a dopant component for stabilizing the crystal lattice of the lithium-rich manganese-based matrix. Its uniform distribution within the matrix creates a continuous and dispersed stabilizing effect within the bulk phase, rather than localized enrichment on the surface. This uniform distribution of M1 can simultaneously regulate the coordination environment of the crystal lattice, reducing stress concentration and structural distortion caused by lithium insertion / extraction during charging and discharging, thereby suppressing microcrack propagation and phase transition instability.

[0093] In some implementations, SEM-EDS testing can be performed on lithium-rich manganese-based materials to determine whether M1 is uniformly distributed in the lithium-rich manganese-based matrix.

[0094] Furthermore, when M1 includes both Mg and Al, Mg and Al jointly participate in the structural regulation of the lithium-rich manganese-based matrix. Mg helps to mitigate local strain and improve the ion migration environment; Al can enhance the strength of the metal-oxygen (MO) bond and improve the stability of the layered structure. Co-doping with Mg and Al can synergistically stabilize the layered structure of lithium-rich manganese-based materials, suppress phase transitions and oxygen release, reduce interfacial impedance, and decrease transition metal dissolution, thereby significantly improving cycle life, thermal stability, and high-temperature performance without significant capacity loss.

[0095] In some embodiments of this application, the Mg content in the lithium-rich manganese-based matrix is ​​400ppm-700ppm; and / or, the Al content is 500ppm-800ppm. This allows for lattice framework strengthening at lower doping levels while avoiding excessive doping that could lead to over-occupancy of active sites, reduced capacity, or localized structural distortion. This parameter range is typically obtained through material cycling tests and structural characterization optimization, balancing initial efficiency, cycle life, and rate performance.

[0096] In some embodiments of this application, the C content in the lithium-rich manganese-based material is 200ppm-1000ppm; and / or the N content is 500ppm-1500ppm. On the one hand, carbon can improve the conductivity of the lithium-rich manganese-based material, buffer the volume expansion during charge and discharge, and inhibit electrode pulverization and active material shedding. On the other hand, nitrogen can optimize the interfacial electronic structure and enhance the bonding force between the coating layer and the lithium-rich manganese-based matrix through doping or coordination, while improving electrolyte wettability, inhibiting side reactions and electrolyte decomposition. Limiting the carbon and / or nitrogen content in the lithium-rich manganese-based material can avoid the carbon-nitrogen layer being too thick, hindering lithium-ion transport and reducing the specific capacity of the lithium-rich manganese-based material, and can also prevent the coating layer from being too low, resulting in insufficient protection and conductivity modification effects. Ultimately, this synergistically achieves a comprehensive improvement in the rate performance, cycle stability, interfacial stability, and long-term electrochemical lifetime of the lithium-rich manganese-based material.

[0097] In some embodiments of this application, when the content of L (e.g., F) in the lithium-rich manganese-based material is 100ppm-300ppm, L can regulate the crystal structure of the material through lattice doping, suppress the layered structure phase transition and lattice distortion during charging and discharging, optimize the lithium-ion diffusion channel, improve ion conduction efficiency, improve electrode interface characteristics, weaken the side reactions between the electrolyte and the active material, and alleviate the problem of transition metal dissolution. Controlling the content of L can effectively avoid the problems of increased lattice defects, decreased structural stability and intensified polarization caused by excessive doping, and can also avoid the disadvantages of insufficient structural modification and interface optimization due to insufficient content, thereby significantly improving the cycle life, rate performance and electrochemical stability of the lithium-rich manganese-based material.

[0098] For example, in lithium-rich manganese-based materials, the content of C can be any of 200ppm, 400ppm, 600ppm, 800ppm, 1000ppm or any combination thereof.

[0099] The content of N can be any one of 500ppm, 800ppm, 1000ppm, 1200ppm, 1500ppm or any combination thereof.

[0100] The content of L can be any one of 100ppm, 150ppm, 200ppm, 250ppm, 300ppm or any combination thereof.

[0101] The Mg content can be any one of 400ppm, 480ppm, 550ppm, 620ppm, 700ppm, or a range of any two of them.

[0102] The Al content can be any one of 500ppm, 580ppm, 650ppm, 720ppm, 800ppm, or any combination thereof.

[0103] In some implementations, ICP-MS can be used to test the Mg and Al content in lithium-rich manganese-based materials, an elemental analyzer can be used to test the C and N content in lithium-rich manganese-based materials, and ion chromatography can be used to test the L content in lithium-rich manganese-based materials.

[0104] In some embodiments of this application, when the ratio of the diameter of the lithium-rich manganese substrate to the thickness of the carbonitride layer 21 is (10-500):1, the carbonitride layer 21 can always be in a "thin and continuous" state; if the ratio of the radius of the lithium-rich manganese substrate to the thickness of the carbonitride layer 21 is too small (<10:1), the carbonitride layer 21 will be too thick, which will easily increase the interfacial impedance; if the ratio of the thickness of the lithium-rich manganese substrate to the carbonitride layer 21 is too large (>500:1), the carbonitride layer 21 will be too thin, making it difficult to form effective protection.

[0105] For example, the ratio of the diameter of the lithium-rich manganese-based substrate to the thickness of the carbon-nitrogen layer 21 can be any of 10:1, 30:1, 50:1, 100:1, 300:1, 500:1 or any combination thereof.

[0106] Furthermore, when the average particle size of the primary particles in the lithium-rich manganese-based material is 0.1-0.7 μm, it is beneficial to improve the uniformity of particle contact after the positive electrode sheet is compacted and to reduce the generation of microcracks during cycling. The average particle size is the average of the length and width of the primary particle, where the length is the maximum value between any two points on the outer contour of the primary particle, and the length and width are perpendicular to each other.

[0107] For example, the average particle size of a primary particle can be a range of any one of 0.1 μm, 0.3 μm, 0.5 μm, 0.7 μm, or any combination thereof.

[0108] Furthermore, when the diameter of the lithium-rich manganese-based matrix is ​​0.1μm-0.7μm, the diffusion path of lithium ions inside the particles is shortened, while maintaining the particle skeleton sufficiently intact, thus avoiding structural embrittlement due to excessive fineness.

[0109] For example, the diameter of the lithium-rich manganese-based substrate can be any of 0.1 μm, 0.3 μm, 0.5 μm, 0.7 μm, or any combination thereof.

[0110] Furthermore, the carbon-nitrogen layer 21 has a thickness of 1nm-10nm, which can construct continuous electron transport channels and chemical protection barriers on the surface of lithium-rich manganese substrates, without excessively hindering lithium ions from passing through the interface.

[0111] For example, the thickness of the carbon-nitrogen layer 21 can be any or any combination of 1 nm, 2 nm, 3 nm, 8 nm, 10 nm.

[0112] In some implementations, the cross-sectional morphology of the positive electrode can be observed using a transmission electron microscope (TEM). The thickness of the lithium-rich manganese-based material coating layer is tested at a location with a complete edge contour and a clear coating layer boundary. During sample preparation, the lithium-rich manganese-based material to be tested is ultrasonically dispersed in ethanol, dropped onto a microgrid copper mesh, and dried. After being mounted on the instrument, the particle edge with a clear boundary between the carbon-nitrogen layer and the lithium-rich manganese-based substrate is located at an appropriate magnification. At least 5 non-overlapping carbon-nitrogen layer areas are randomly selected as test points. The actual thickness of the carbon-nitrogen layer at each point is measured one by one along the normal direction perpendicular to the interface between the lithium-rich manganese-based substrate and the carbon-nitrogen layer. Five sets of thickness data are recorded. After removing abnormal deviation values, the arithmetic mean is calculated. This average value is used as the final thickness of the carbon-nitrogen layer of the sample. At the same time, the uniformity of the carbon-nitrogen layer thickness is corroborated by multiple particle retest data.

[0113] In some implementations, the positive electrode can be subjected to SEM testing to obtain an SEM image of the positive electrode, and the average particle size of the primary particles can be determined based on the SEM image of the positive electrode. Since the thickness of the carbon-nitrogen layer is very thin relative to the thickness of the lithium-rich manganese substrate, the diameter of the lithium-rich manganese substrate can be considered equivalent to the average particle size of the primary particles.

[0114] When the dimensions of various components of a lithium-rich manganese-based material meet the aforementioned ranges, on the one hand, the smaller particle diameter can shorten the bulk diffusion distance; on the other hand, the nanoscale carbonitridium layer 21 suppresses electrolyte erosion, transition metal dissolution, and interfacial side reactions. Thus, under high-voltage cycling or solid-state interface contact conditions, it balances rate performance, cycle stability, and low interfacial impedance. Through this synergistic size design, the carbonitridium layer 21 can both conduct electricity and buffer without significantly sacrificing capacity release, making it easier for lithium-rich manganese-based materials to achieve a stable charge-discharge platform and longer service life in practical battery systems.

[0115] In some embodiments of this application, when the area coverage of the protrusion structure 22 in the primary particles is 10%-50%, a sufficient number of solid electrolyte contact sites can be introduced while retaining the buffering and conductive functions of the carbonitridium layer 21. This allows lithium ions to migrate rapidly across the interface along the protrusion region, thereby reducing interfacial impedance. If the coverage is too low, there are insufficient solid electrolyte contact points; if the coverage is too high, the continuous buffering effect of the carbonitridium layer 21 is easily weakened. Therefore, this range balances ion conduction and protection of the lithium-rich manganese substrate. The coverage of the protrusion structure 22 refers to the area coverage of the protrusion structure 22 on the surface of the carbonitridium layer 21 away from the lithium-rich manganese substrate.

[0116] For example, the coverage of the protrusion structure 22 can be a range of 10%, 20%, 30%, 40%, 50%, or any combination thereof.

[0117] In some implementations, SEM-EDS can be used in conjunction with image analysis software (such as ImageJ) to calculate area coverage.

[0118] This application does not specifically limit the solid electrolyte, and it can be any solid electrolyte commonly used in the art. Exemplarily, the solid electrolyte includes at least one of lithium aluminum titanium phosphate, lithium lanthanum zirconium oxide, lithium aluminum silicon titanium phosphate, lithium lanthanum titanium oxide, and lithium lanthanum zirconium tantalum oxide. These solid electrolytes possess high lithium-ion conductivity and good chemical stability, and can serve as the host phase of the protrusion structure 22, reducing side reactions with the electrolyte or solid electrolyte system, and providing continuous ion channels on the surface of lithium-rich manganese-based particles, thereby improving interfacial stability and cycle life under high voltage. Further, the solid electrolyte includes lithium aluminum titanium phosphate.

[0119] By setting the width of the protrusion structure 22 to 0.5-3 nm, and / or setting the maximum height of the protrusion structure 22 to 1 nm-30 nm, and / or ensuring that the spacing D between two adjacent protrusion structures satisfies 0 < D ≤ 300 nm, the protrusion structure 22 can maintain a discrete distribution characteristic at the nanoscale. This ensures that the protrusion structure 22 can form an effective short-range ion transport path, while avoiding excessively large protrusion structures 22 that could lead to surface stress concentration or embrittlement of the coating layer. Furthermore, the smaller width and controlled height help improve the uniformity of adhesion between the lithium-rich manganese-based material and the external electrolyte, while the smaller spacing results in a more uniform ion flux distribution, thereby further reducing polarization and enhancing structural stability during charge and discharge processes.

[0120] For example, the width of the protrusion structure 22 can be any of 0.5nm, 1nm, 1.5nm, 2nm, 3nm or any combination thereof;

[0121] The maximum height of the protrusion structure 22 can be any one of 1nm, 2nm, 3nm, 10nm, 20nm, 25nm, 30nm or any combination thereof;

[0122] The spacing D between two adjacent protrusions 22 can be any one of 0.1nm, 3nm, 10nm, 40nm, 100nm, 150nm, 200nm, 250nm, 300nm, or any combination thereof.

[0123] In some implementations, the width, maximum height, and D of the protrusions in the lithium-rich manganese-based material can be determined from the atomic force microscopy (AFM) images of the material.

[0124] In some embodiments of this application, the lithium-rich manganese-based material includes secondary particles formed by primary particle agglomeration, and the span of the secondary particles is 0.8-1.5.

[0125] In this application, Span = (Dv90 - Dv10) / Dv50. Span is used to characterize the dispersion of the particle size distribution of lithium-rich manganese-based materials. The closer Span is to a smaller value, the more concentrated the particle size, which is more conducive to slurry dispersion, uniform coating, and consistent compaction. When the Span of secondary particles is 0.8-1.5, it can avoid fluctuations in pore structure, uneven local density of the electrode, and inconsistent electrochemical reactions caused by the coexistence of large and small particles, thereby improving the stability of the electrode fabrication and the consistency of cycling.

[0126] For example, Span is a range consisting of any one of 0.8, 0.9, 1, 1.4, 1.5, or any two of them.

[0127] In some embodiments of this application, the Dv50 of the secondary particles of the lithium-rich manganese-based material is 1μm-5μm to balance particle packing density, ion diffusion path, and processing rheology. Too small a particle size leads to increased specific surface area and intensified interfacial side reactions, while too large a particle size prolongs lithium-ion transport distance and increases polarization. Therefore, controlling the Dv50 of the secondary particles of the lithium-rich manganese-based material to 1μm-5μm maintains a low transport impedance while ensuring high compaction density, allowing the electrode to maintain good rate performance and structural stability under high-voltage charge-discharge conditions.

[0128] For example, the Dv50 of secondary particles can be a range of any one of 1 μm, 2 μm, 3 μm, 5 μm, or any two of them.

[0129] Furthermore, the Dv50 of the secondary particles of the lithium-rich manganese-based material is 3μm-4μm.

[0130] In some implementations, a laser particle size analyzer can be used to test the Dv10, Dv50, and Dv90 of secondary particles of lithium-rich manganese-based materials, and then calculate the Span.

[0131] In some embodiments of this application, the powder conductivity of the lithium-rich manganese-based material is ≥1. 10 -5 At a conductivity of S / cm, the ohmic impedance of the electrode can be reduced, making electron transport easier between lithium-rich manganese-based material particles. This is mainly because the synergistic improvement in the conductive network by the coating layer and the particle size of the lithium-rich manganese-based material reduces interfacial charge accumulation, thereby improving rate performance. For example, the powder conductivity can be 1. 10 -5 S / cm, 1.5 10 -5 S / cm, 2 10 -5 S / cm, 1 10 -4 S / cm, 1 10 -3 The range consisting of any one of S / cm or any two of them.

[0132] In some embodiments, the powder conductivity can be tested by a method including the following steps: using a powder resistivity tester, weighing 0.5g of lithium-rich manganese-based material, adding it into the mold cavity through a weighing boat and using vibration to make the lithium-rich manganese-based material flat and uniform, then slowly placing the four-probe mold assembly punch on it, installing the four-probe mold assembly onto the main unit, connecting the BNC data cable, closing the protection door, opening the software to set the parameters, setting the pressure to 12MPa, and starting the test, the software automatically reads the conductivity value.

[0133] In some embodiments of this application, the specific surface area of ​​the lithium-rich manganese-based material is 1 m². 2 / g-4m 2 At a specific surface area of ​​1 m² / g, while ensuring the capacity of the lithium-rich manganese-based material, sufficient electrolyte contact can be achieved, while avoiding excessive side reactions caused by excessive surface area. This facilitates ion migration across the interface and inhibits excessive formation of the interfacial reaction layer, thereby ensuring cycle stability. For example, the specific surface area of ​​the lithium-rich manganese-based material can be 1 m² / g. 2 / g、2m 2 / g、3m 2 / g、4m 2 A range consisting of any one of / g or any two of them.

[0134] In some embodiments, the specific surface area of ​​lithium-rich manganese-based materials can be tested by a method including the following steps: weighing the total weight of the empty sample tube and the stopper; immersing the lithium-rich manganese-based material in anhydrous ethanol for 4 hours; then removing the lithium-rich manganese-based material and drying it in an oven at 105°C for half an hour; placing the lithium-rich manganese-based material into the sample tube; weighing the total weight of the lithium-rich manganese-based material, the sample tube, and the stopper to calculate the mass of the lithium-rich manganese-based material; opening the degassing station; placing the sample tube containing the lithium-rich manganese-based material into the degassing station at 105°C; purging with nitrogen (pure nitrogen) for 30 minutes; cooling for 15 minutes; and then testing at 25°C and 60% humidity; using P / P0 (points in the range of 0.05-0.25) as the x-axis and P / V (P0P) as the y-axis; performing linear fitting by plotting the specific surface area (BET) equation to obtain the slope and intercept of the straight line, thereby calculating the specific surface area of ​​the lithium-rich manganese-based material.

[0135] In some embodiments of this application, the surface LiOH content of the lithium-rich manganese-based material is <500ppm, which can significantly reduce the alkaline residue on the surface of the lithium-rich manganese-based material, reduce the probability of it reacting with electrolytes, binders or environmental moisture to generate by-products, achieve surface chemical inertization, and slow down the growth of interface impedance during electrode processing and service.

[0136] For example, the surface LiOH content of the lithium-rich manganese-based material can be in the range of any one of 499ppm, 300ppm, 200ppm, 100ppm, or any combination thereof.

[0137] In some embodiments of this application, when the surface Li2CO3 content of the lithium-rich manganese-based material is <800ppm, the gas side reaction induced by carbonate under high voltage conditions and the interfacial film thickening can be reduced. By reducing residual carbonate, the contact uniformity between particles and electrolyte can be improved and the continuity of lithium-ion migration can be enhanced.

[0138] For example, the Li2CO3 content on the surface of the lithium-rich manganese-based material can be any of 799ppm, 499ppm, 300ppm, 200ppm, 100ppm, or any combination thereof.

[0139] In some embodiments, the surface LiOH and Li2CO3 content of lithium-rich manganese-based materials can be tested using a method including the following steps: at 25°C, 30g of lithium-rich manganese-based cathode material is placed in 100g of water, stirred thoroughly, and then filtered to obtain a lithium-rich manganese-based cathode material solution. The solution is titrated with a standard hydrochloric acid solution, and the residual alkali content (LiOH and Li2CO3 content) of the lithium-rich manganese-based cathode material solution is calculated based on the results.

[0140] In some implementations, the combination of powder conductivity, moderate specific surface area and low residual alkali content ensures the processing adaptability of lithium-rich manganese-based materials while reducing interfacial impedance and side reactions, thereby enabling lithium-rich manganese-based materials to exhibit higher capacity retention and better stability under high rate and long cycle conditions.

[0141] In some embodiments of this application, the X-ray diffraction pattern of the lithium-rich manganese-based material has characteristic peaks of the (003) plane with 2θ of 18.4°-18.5° and characteristic peaks of 2θ of 26.7°-27.1°.

[0142] Among them, the characteristic peak of the (003) plane shifts to a lower angle because Mg and Al doping can form strong ionic metal-oxygen bonds in the lattice of lithium-rich manganese-based materials, and the ionic radii of Mg and Al are large, which will cause the c-axis of the cell of the lithium-rich manganese-based materials to expand, causing the characteristic peak of the (003) plane to move to a lower angle; the characteristic peak of 26.7°-27.1° is an amorphous carbon-nitrogen characteristic peak, proving that the lithium-rich manganese-based materials include a carbon-nitrogen layer 21.

[0143] In some embodiments of this application, the X-ray diffraction pattern of the lithium-rich manganese-based material has a characteristic peak with 2θ of 29.3°-29.6°. The characteristic peak of 29.3°-29.6° is the characteristic peak of the solid electrolyte lithium aluminum titanium phosphate (LATP), proving that the lithium-rich manganese-based material includes the LATP solid electrolyte.

[0144] In some embodiments of this application, the full width at half maximum (FWHM) of the characteristic peaks on the (003) plane in the X-ray diffraction pattern of the lithium-rich manganese-based material is 0.13-0.149.

[0145] The reason is that M1 and M2 are doped into the lithium-rich manganese-based material, which makes the half-width of the characteristic peak of the (003) plane of the lithium-rich manganese-based material narrower. This indicates that the layered structure of the lithium-rich manganese-based material is more ordered, the crystallinity is enhanced, the grain size is increased, the lattice strain is reduced, and the overall structure is more complete and more stable.

[0146] For example, the half-width of the characteristic peak of the (003) surface can be any one of 0.13, 0.134, 0.137, 0.14, 0.145, 0.149 or any two of them.

[0147] In some embodiments of this application, in the X-ray diffraction pattern of lithium-rich manganese-based materials, the intensity I of the characteristic peak of the (003) plane is... （003） The intensity I of the characteristic peak of the (104) surface （104） The ratio of I （003） / I （104） It is 1.78-1.9, I (003) / I (104) The higher value indicates that the lithium-rich manganese-based material has better crystallinity and higher grain integrity.

[0148] For example, I （003） / I （104） It can be a range consisting of any one of 1.78, 1.8, 1.87, 1.9, or any two of them.

[0149] Some embodiments of this application also provide a method for preparing the above-mentioned lithium-rich manganese-based material, including:

[0150] 1) The raw material source, M1 source and M2 source are subjected to a co-precipitation reaction to obtain a lithium-rich manganese-based material precursor including M1 and M2;

[0151] 2) The lithium-rich manganese-based material precursor was mixed with LiL to obtain a mixture, and the mixture was subjected to three-stage calcination treatment to obtain the lithium-rich manganese-based matrix.

[0152] Specifically, the process includes: first, heating to T1 at 1-3℃ / min, maintaining a temperature of 500℃≤T1≤600℃, and holding the temperature for 300-500min for the first roasting treatment; then, heating to T2 at 2-5℃ / min, maintaining a temperature of 850℃≤T2≤900℃, and holding the temperature for 600-800min for the second roasting treatment; and finally, heating to T3 at 1-9℃ / min, maintaining a temperature of 900℃<T3≤1200℃, and holding the temperature for 300-500min for the third roasting treatment.

[0153] 3) Under a nitrogen atmosphere, a lithium-rich manganese-based matrix and melamine are mixed and sintered to obtain an intermediate lithium-rich manganese-based material including a carbon-nitrogen layer; wherein the sintering temperature is 400-600℃.

[0154] 4) After mixing the intermediate lithium-rich manganese-based material with the solid electrolyte, sintering is performed to obtain a lithium-rich manganese-based material including the solid electrolyte; wherein the sintering temperature is 300-600℃.

[0155] The raw material sources include at least nickel and manganese sources, and may also include cobalt sources; M1 source includes Mg source and / or Al source; M2 source includes at least one of Zr source, Nb source, Ru source, V source, Ta source, Mo source, W source, Ti source, and Cr source; L includes at least one of F, Cl, Br, and I.

[0156] Specifically, a mixture comprising a lithium-rich manganese-based material precursor and LiL is subjected to three-stage sintering at a maximum temperature of T3 (900℃ < T3 ≤ 1200℃). This process enables thorough oxidation of the lithium-rich manganese-based material precursor. By utilizing the different ionic radii of various elements, a uniform gradient distribution of doping elements is achieved, resulting in a central core layer 11 and a high-entropy layer 12 located on at least a portion of the outer surface of the central core layer 11. This aims to improve the conductivity of the lithium-rich manganese-based material, enhance the electrochemical performance of the battery, and reduce oxygen release. Simultaneously, L-doping of LiL is incorporated into the outermost layer of the lithium-rich manganese-based matrix, replacing O and forming an oxygen hole layer 13. Subsequently, the lithium-rich manganese-based matrix is... When melamine (C3H6N6) is mixed under a nitrogen atmosphere and sintered, the C3N4 generated by the decomposition of melamine will uniformly coat the surface of the lithium-rich manganese-based matrix, improving the electronic conductivity of the lithium-rich manganese-based material. At the same time, the reducing atmosphere (such as NH3 and nitrogen-containing free radicals) generated by the pyrolysis of melamine will react with the lattice oxygen on the surface of the lithium-rich manganese-based matrix to generate oxygen vacancies, further promoting the formation of the oxygen hole layer 13. Finally, the intermediate lithium-rich manganese-based material is mixed with a solid electrolyte and sintered, which can form a protruding structure containing solid electrolyte on the surface of the carbon-nitrogen layer 21 away from the lithium-rich manganese-based matrix, thereby further improving the ionic conductivity of the lithium-rich manganese-based material.

[0157] In this application, an M1 source is added during the preparation of the lithium-rich manganese-based material precursor, thus enabling the M1 element to be uniformly distributed inside the lithium-rich manganese-based material precursor and subsequently uniformly distributed inside the lithium-rich manganese-based matrix. During the calcination treatment of the lithium-rich manganese-based material precursor and LiL, the M2 element in the M2 source undergoes in-situ solid-state diffusion and interfacial reaction along with elements such as Li, Ni, Co, Mn, and O. Due to the difference in ionic radius and valence state of the M2 element, it is difficult for it to enter the lattice of the lithium-rich manganese-based matrix in large quantities. It is more likely to accumulate on the surface of the lithium-rich manganese-based matrix and react with the transition metal ions (Ni, Co, Mn) dissolved from the lithium-rich manganese-based matrix and the lithium source to form a high-entropy layer 12 with multiple principal elements and high configurational entropy in situ. L will penetrate into the interior of the lithium-rich manganese-based material precursor, replacing O and forming an oxygen hole layer 13 around the high-entropy layer 12.

[0158] Furthermore, in the multi-stage roasting process of step 2) of this application, the temperature of the first roasting process is T1, 500℃≤T1≤600℃, which is the dissolution temperature of LiL. After dissolution, it can promote the diffusion of Li and make Li uniformly distributed inside the lithium-rich manganese-based material precursor. The temperature of the second roasting process is T2, 850℃≤T2≤900℃, which is the main stage for the formation of the layered structure in the lithium-rich manganese-based material and determines the size of the primary particles and the properties such as lithium-nickel mixing. The temperature of the third roasting process is T3, 900℃<T3≤1200℃, which can further stabilize the layered structure of the lithium-rich manganese-based material and make the size of the lithium-rich manganese-based material more uniform.

[0159] A second aspect of this application provides a lithium-ion secondary battery, including a positive electrode sheet. The positive electrode sheet includes a positive current collector and a positive active layer disposed on at least one side surface of the positive current collector in the thickness direction. The positive active layer includes a positive active material; the positive active material includes the aforementioned lithium-rich manganese-based material.

[0160] When the above-mentioned cathode material is used in the cathode of a lithium-ion battery, a lithium-rich manganese-based matrix with a specific composition and a surface composite coating structure can be introduced into the electrode system, thereby ensuring both the stability of the main structure and the interface stability during charge and discharge. The doping elements in the lithium-rich manganese-based matrix help alleviate the lattice distortion and phase transition tendency of the layered structure under high-voltage cycling, making it easier to balance capacity release and cycle life. The carbon-nitrogen layer 21 on the particle surface and the protruding structure 22 containing solid electrolyte help reduce direct side reactions between the active surface and the external medium, thereby improving lithium-ion transport contact conditions and reducing interface impedance. Therefore, the cathode made from this lithium-rich manganese-based material can achieve better rate performance, cycle stability, and voltage retention, and is beneficial for improving the overall electrochemical performance and safety in liquid, semi-solid, or solid batteries.

[0161] Especially when the battery is an all-solid-state battery, the protruding structure 22 in the coating layer on the surface of the positive electrode particles helps to increase the effective contact area between the positive electrode and the solid electrolyte, making the interfacial ion transport channels more continuous, thereby reducing contact resistance and mitigating interfacial side reactions. Therefore, this battery can maintain high discharge capacity, low polarization, and good cycle stability even at higher operating voltages, while improving safety and application reliability.

[0162] This application also provides an electronic device including the aforementioned battery. This battery exhibits excellent energy density and cycle performance under high voltage, making it suitable for various electronic devices (e.g., new energy vehicles and energy storage devices).

[0163] The present invention will be further described below with reference to specific embodiments.

[0164] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; and the reagents and materials are commercially available unless otherwise specified.

[0165] Example 1

[0166] The lithium-rich manganese-based material in this embodiment is prepared by a method including the following steps:

[0167] 1) Prepare a mixed salt solution of NiSO4, CoSO4, MnSO4, MgSO4, Al2(SO4)3, W2(SO4)3, and Ti(SO4)2, and a mixed alkaline solution of NaOH and NH3·H2O. The total metal ion concentration of the mixed salt solution is 2 mol / L. 2+ Co 2+ Mn 2+ Mg 2+ Al 3+ :W 6+ Ti 4+ The molar ratio of NaOH to NH3·H2O was 0.125:0.125:0.74:0.0025:0.0025:0.0025, with a molar concentration of 3 mol / L and 0.2 mol / L. A certain amount of deionized water was added to the reactor, and the salt solution was pumped into the reactor at a feed rate of 175 mL / h using a peristaltic pump. The stirring speed was controlled at 1000 rpm, the circulating water temperature at 55℃, and the alkali feed rate was adjusted using a three-stage speed control to maintain the pH of the solution at 7.5. The feeding time was 30 h. After the reaction, the slurry was subjected to solid-liquid separation, centrifuged and washed with deionized water, and then dried at 120℃ for 24 h to obtain a metal-doped hydroxide precursor, Ni. 12.5 Co 12.5 Mn 74 Al 0.25 Mg 0.25 W 0.25 Ti 0.25 (OH)2.

[0168] 2) The hydroxide precursor was mixed with LiOH·H2O and LiF, with n(Li):n(Me) = 1.62:1, where Me is Ni, Co, Mn, Al, Mg, W, or Ti, and n(F):n(Me) = 0.001:1. After thorough mixing, the mixture was placed in a muffle furnace. The temperature was first increased to 500℃ at 1℃ / min and held for 300 min for the first calcination treatment. Then, the temperature was increased to 850℃ at 2℃ / min and held for 600 min for the second calcination treatment. Finally, the temperature was increased to 1000℃ at 1℃ / min and held for 300 min for the third calcination treatment. The product after the third calcination treatment was removed and ground to obtain a lithium-rich manganese-based matrix (Li2MnO3) with a specific span. 0.62 (LiNi 0.329 Co 0.329 Mn 0.31 5Al 0.00675 Mg 0.00675 W 0.00675 Ti 0.00675 O 1.99305 F 0.00695 ) 0.38 ;

[0169] The lithium-rich manganese-based matrix consists of a central core layer, a high-entropy layer, and an oxygen-hole layer from the inside out. The oxygen-hole layer includes F element, and the high-entropy layer includes W, Ti, Ni, Co, and Mn.

[0170] 3) Mix 100g of the above lithium-rich manganese-based matrix, 4g of Co(OH)2 and 0.1g of melamine. After mixing evenly, put the mixture into a muffle furnace, purge with nitrogen, heat to 600℃ at 2℃ / min, and sinter for 600min to obtain an intermediate lithium-rich manganese-based material including a carbon-nitrogen layer.

[0171] 4) The intermediate lithium-rich manganese-based material including the carbon-nitrogen layer was mixed evenly with 0.1g of LATP to obtain a mixture. The mixture was placed in a muffle furnace, air was introduced, the temperature was increased to 500℃ at 2℃ / min, and sintered for 600min to obtain a lithium-rich manganese-based material including a protruding structure. The protruding structure included LATP, and the coverage of the protruding structure was 30%.

[0172] The width of the protrusion is 1.7 nm, the maximum height of the protrusion is 15 nm, and the spacing between two adjacent protrusions is 35 nm.

[0173] The specific parameters of lithium-rich manganese-based materials are shown in Tables 1-4.

[0174] Example 2

[0175] The preparation method of the lithium-rich manganese-based material in this embodiment is basically the same as that in Example 1, except that:

[0176] Step 1) does not include Al2(SO4)3, and the protrusion structure in step 4) includes LLZO.

[0177] Example 3

[0178] The preparation method of the lithium-rich manganese-based material in this embodiment is basically the same as that in Example 1, except that:

[0179] Step 1) does not include MgSO4, and the protrusion structure in step 4) includes LASTP.

[0180] Example 4

[0181] The preparation method of the lithium-rich manganese-based material in this embodiment is basically the same as that in Example 1, except that:

[0182] In step 1), Zr(SO4)2 and V2(SO4)3 are used to replace W2(SO4)3 and Ti(SO4)2;

[0183] In step 2), LiCl is used to replace LiF; the oxygen hole layer of the lithium-rich manganese-based matrix includes Cl, and the high-entropy layer includes Zr, V, Ni, Co, and Mn.

[0184] Example 5

[0185] The preparation method of the lithium-rich manganese-based material in this embodiment is basically the same as that in Example 1, except that:

[0186] In step 2), LiCl is used to replace LiF; the oxygen hole layer of the lithium-rich manganese-based matrix includes Cl.

[0187] The differences between the preparation methods of lithium-rich manganese-based materials in Examples 6-16 and those in Example 1 are shown in Tables 1-4. In Examples 14-16, the lithium-rich manganese-based matrix after grinding in step 2) was sieved to obtain the lithium-rich manganese-based matrix of target Dv50 and Span, and then the lithium-rich manganese-based materials of target Dv50 and Span were obtained.

[0188] The difference between the preparation methods of the lithium-rich manganese-based material in Comparative Example 1 and the lithium-rich manganese-based material in Example 1 is that Al and Mg were not doped in the preparation of the lithium-rich manganese-based material precursor.

[0189] The difference between the preparation methods of the lithium-rich manganese-based material in Comparative Example 2 and the lithium-rich manganese-based material in Example 1 is that W and Ti were not doped in the preparation of the lithium-rich manganese-based material precursor.

[0190] The difference between the preparation methods of the lithium-rich manganese-based material in Comparative Example 3 and the lithium-rich manganese-based material in Example 1 is that in step 3), LiOH is used to replace LiF, and melamine is not added to obtain the intermediate lithium-rich manganese-based material.

[0191] The difference between the preparation method of the lithium-rich manganese-based material in Comparative Example 4 and the lithium-rich manganese-based material in Example 1 is that step 4 is not included, and intermediate lithium-rich manganese-based material is used as the lithium-rich manganese-based material.

[0192] Performance testing

[0193] The lithium-rich manganese-based materials in the examples and comparative examples were subjected to the following performance tests, and the results are shown in Tables 1-3:

[0194] (I) Testing of physical properties of lithium-rich manganese-based materials

[0195] 1) XRD test

[0196] XRD tests were performed on the lithium-rich manganese-based materials in the examples and comparative examples to obtain the peak positions, half-peak widths, and intensities of each characteristic peak in the XRD patterns.

[0197] Figure 2 The XRD patterns of lithium-rich manganese-based materials in Examples 1 and 1-4 are shown below. Figure 2 It can be seen that the 2θ of the characteristic peak of the (003) plane of the lithium-rich manganese-based material in Comparative Example 1 is 18.35-18.4°, the 2θ of the characteristic peak of the (003) plane of the lithium-rich manganese-based material in Comparative Example 2 is 18.6-18.7°, while the 2θ of the characteristic peak of the (003) plane of the lithium-rich manganese-based materials in Examples 1 and Comparative Examples 3-4 is 18.4-18.5°. This is because, compared with Example 1, Comparative Example 1 did not dope with Al or Mg elements. 3+ Compared to transition metal ions, the size is smaller, and doping will cause a slight shrinkage of the lattice and a slight decrease in the c-axis, resulting in a slight shift of the characteristic peak of the (003) crystal plane to a higher angle. 2+ The size is comparable to that of transition metal ions, and doping has no significant effect on the (003) crystal plane. Therefore, the (003) peak position in Comparative Example 1 is lower than that in Example 1. Comparative Example 2 is undoped with W and Ti elements. 6+ The size is much larger than that of transition metal ions, and doping will cause lattice expansion, increase the c-axis, and cause the (003) crystal plane to shift at a low angle. 4+The size difference between the two transition metal ions is not significant, and the doping has no obvious effect on the (003) crystal plane. Therefore, the position of the (003) crystal plane in Comparative Example 2 is higher than that in Example 1. The lithium-rich manganese-based materials in Example 1 and Comparative Examples 3-4 are all doped with Mg, Al, W and Ti, and the characteristic peaks of the (003) plane are in similar positions. Compared with Comparative Example 4, the characteristic peaks of LATP appear in Example 1 and Comparative Examples 1-3 at 29.3-29.6°, indicating that the lithium-rich manganese-based materials in Example 1 and Comparative Examples 1-3 include LATP. Compared with Comparative Example 3, the lithium-rich manganese-based materials in Example 1, Comparative Examples 1-2 and 4 have weak characteristic peaks at 26.7-27.1°, which are characteristic peaks of the amorphous CN layer.

[0198] 2) SEM testing

[0199] SEM tests were performed on the lithium-rich manganese-based materials of the examples and comparative examples to obtain SEM images of the lithium-rich manganese-based materials.

[0200] Figure 3 This is a SEM image of the lithium-rich manganese-based material of Example 1 at a certain magnification. Figure 4 SEM image of the lithium-rich manganese-based material in Comparative Example 1; Figure 5 SEM image of the lithium-rich manganese-based material in Comparative Example 2; Figure 6 SEM image of the lithium-rich manganese-based material in Comparative Example 3; Figure 7 The image shows a SEM image of the lithium-rich manganese-based material in Comparative Example 4. From... Figures 3-7 It can be seen that, from Figure 3 It can be seen that the lithium-rich manganese-based material in Example 1 is a quasi-single-crystal material; specifically, from Figure 3 as well as Figure 4 It can be seen that the average particle size of the primary particles in the lithium-rich manganese-based material of Example 1 is smaller than that in Comparative Example 1, indicating that doping the lithium-rich manganese-based material with Mg and Al can refine the particle size of the primary particles; from Figure 3 as well as Figure 5 It can be seen that the average particle size of the primary particles of the lithium-rich manganese-based material in Example 1 is smaller than that of the primary particles of the lithium-rich manganese-based material in Comparative Example 2, indicating that doping W and Ti into the lithium-rich manganese-based material can refine the particle size of the material. Figure 3 as well as Figure 6 It can be seen that the surface of the lithium-rich manganese-based material in Example 1 has powdery substances, indicating that the lithium-rich manganese-based material in Example 1 includes a carbon-nitrogen layer; from Figure 3 as well as Figure 7 It can be seen that the surface of the lithium-rich manganese-based material in Example 1 has island-like white spots, and the surface lithium-rich manganese-based material includes a protruding structure.

[0201] 3) SEM-EDS test

[0202] SEM-EDS tests were performed on the cross sections of the lithium-rich manganese-based materials in the examples and comparative examples to observe the distribution of each element in the lithium-rich manganese-based materials.

[0203] Figure 8 This is a SEM image of the lithium-rich manganese-based material of Example 1 at another magnification. Figure 9 for Figure 8 Distribution diagram of Ni element in lithium-rich manganese-based materials; Figure 10 for Figure 8 Distribution diagram of Mn element in lithium-rich manganese-based materials; Figure 11 for Figure 8 Distribution diagram of Co element in lithium-rich manganese-based materials; Figure 12 for Figure 8 Distribution diagram of Al element in lithium-rich manganese-based materials; Figure 13 for Figure 8 Distribution diagram of Mg element in lithium-rich manganese-based materials; Figure 14 for Figure 8 Distribution diagram of Ti element in lithium-rich manganese-based materials; Figure 15 for Figure 8 Distribution diagram of W element in lithium-rich manganese-based materials; Figure 16 for Figure 8 Distribution diagram of F element in lithium-rich manganese-based materials. From Figure 8-16 It can be seen that Al and Mg elements are uniformly distributed inside the lithium-rich manganese-based material, while W, Ti, and F are distributed at the edge of the lithium-rich manganese-based material.

[0204] (II) Electrochemical performance testing

[0205] 1) Electrochemical performance testing of all-solid-state batteries

[0206] A. The lithium-rich manganese-based materials used in the examples and comparative examples are prepared into all-solid-state batteries. The preparation method includes:

[0207] a. Preparation of the positive electrode sheet

[0208] A mixture of lithium-rich manganese-based material, lithium phosphorus sulfur chlorine and conductive carbon black was dry-mixed under inert conditions (humidity <1ppm) at a mass ratio of 60:30:10. The mixture was then ball-milled at 400rpm for 3h. After ball milling, a positive electrode sheet (120μm thick) including a positive electrode active layer was formed by hot rolling (100℃, 15MPa).

[0209] b. Preparation of negative electrode sheet

[0210] A lithium metal foil with a thickness of 45 μm was polished until Ra ≤ 0.1 μm to obtain a negative electrode.

[0211] c. Assembly of all-solid-state batteries

[0212] A solid electrolyte membrane (45 μm thick) is obtained by rolling a mixture of lithium, phosphorus, sulfur, chlorine and polytetrafluoroethylene (PTFE) at a mass ratio of 6:1. The positive electrode and the solid electrolyte membrane are then hot-pressed (180 °C, 8 MPa) to obtain a composite positive electrode-solid electrolyte layer. Finally, a negative electrode is pressed onto the surface of the composite positive electrode-solid electrolyte layer away from the positive electrode to obtain an all-solid-state battery.

[0213] B. The following electrochemical performance tests were performed on the prepared all-solid-state battery:

[0214] a. 0.1C Discharge Capacity Test: The test environment temperature was 45℃±1℃. The charge and discharge regimes were as follows: Rate charging: 0.1C, until the voltage ≥ 4.2V; Constant voltage charging: 4.2V, until the current ≤ 0.02mA; Let stand for 10 minutes; Rate discharging: 0.1C, until the voltage ≤ 1.9V; Let stand for 10 minutes, and test the discharge specific capacity.

[0215] b. Capacity retention test of 1C cycle: The test environment temperature is 45℃±1℃. The charging rate is 1C until the voltage is ≥4.2V; the constant voltage charging rate is 4.2V until the current is ≤0.02mA; the cycle is left to stand for 10 minutes; the discharging rate is 1C until the voltage is ≤1.9V; the cycle is left to stand for 10 minutes, and the discharge specific capacity of the first cycle is tested; the charging rate and discharging rate cycles are repeated, and the discharge specific capacity of 100 cycles is tested. The cycle capacity retention rate of 100 cycles is calculated.

[0216] Figure 17 The image shows the discharge curves of all-solid-state batteries using lithium-rich manganese-based materials, including Examples 1 and Comparative Examples 1-4. From... Figure 17 It can be seen that the all-solid-state battery in Example 1 has better cycle performance.

[0217] c. Rate performance test: The ratio of the 1C first-cycle discharge specific capacity to the 0.1C discharge specific capacity is multiplied by 100%.

[0218] 2) Electrochemical performance testing of liquid lithium-ion batteries

[0219] A. The lithium-rich manganese-based materials from the examples and comparative examples are used to prepare liquid lithium-ion batteries. The preparation method includes:

[0220] a. Preparation of the positive electrode sheet

[0221] A positive electrode slurry was prepared by mixing lithium-rich manganese-based material, Super P, and PVDF in a mass ratio of 8:1:1 and adding NMP. The positive electrode slurry was coated on both sides of an aluminum foil, and after drying and rolling, a positive electrode active layer was formed on both sides of the aluminum foil to obtain a positive electrode sheet.

[0222] b. Preparation of button-type liquid lithium-ion batteries

[0223] The positive electrode was punched into a small circular piece with a diameter of 12 mm using a film punch. After drying and weighing, it was assembled into a coin cell in a glove box under an Ar protective atmosphere, using a Li metal disc as the negative electrode and an electrolyte (composed of 1.2 mol / L LiPF6, with DMC and FEC as solvents, and a volume ratio of DMC to FEC of 3:7).

[0224] c. Preparation of full cells

[0225] Graphite, Super P, and SBR are mixed in a mass ratio of 8:1:1, and deionized water is added to prepare a negative electrode slurry. The negative electrode slurry is coated on both sides of a copper foil. After drying and rolling, a negative electrode active layer is formed on both sides of the copper foil to obtain a negative electrode sheet.

[0226] The positive electrode, separator, and negative electrode are assembled into a full cell; the separator used is a PP / PE material separator; the composition of the electrolyte is as follows: the mass ratio of DMC to FEC is 3:7, and the concentration of LiPF6 in the electrolyte is 1.2 mol / L.

[0227] B. The prepared liquid lithium-ion battery was subjected to the following electrochemical performance tests:

[0228] a. 0.1C discharge capacity test of button lithium-ion battery: At 25℃, the battery is charged at a rate of 0.1C until the voltage is ≥4.6V; charged at a constant voltage of 4.6V until the current is ≤0.02mA; left to stand for 10 minutes; discharged at a rate of 0.1C until the voltage is ≤2V; left to stand for 10 minutes, and the discharge capacity of the battery is tested.

[0229] b. Capacity retention test of full battery after 100 cycles at 1C: At 25℃, charge at a constant current rate of 0.1C to a voltage of 4.6V, then charge at a constant voltage of 4.6V to a current of 0.02mA, then let stand for 10 minutes, and then discharge at a constant current rate of 0.1C to a voltage of 2V. The capacity at this time is recorded as the discharge specific capacity at the 0.1C rate.

[0230] Rest for 10 minutes; Charge at 1C until voltage ≥ 4.6V; Charge at 4.6V until current ≤ 0.02mA; Rest for 10 minutes; Discharge at 1C until voltage ≤ 2V; Rest for 10 minutes, then test the discharge specific capacity at 1C rate for the first cycle; Repeat the 1C rate charging and discharging steps, test the discharge specific capacity after 100 cycles, and calculate the cycle capacity retention rate after 100 cycles.

[0231] Figure 18 The discharge curves are shown for liquid lithium-ion batteries containing lithium-rich manganese-based materials, including Examples 1 and Comparative Examples 1-4. Figure 18 It can be seen that the liquid lithium-ion battery in Example 1 has better cycle performance.

[0232] c. Full battery rate performance test: The ratio of the 1C first discharge specific capacity to the 0.1C discharge specific capacity multiplied by 100%.

[0233] Table 1

[0234]

[0235] In Table 1, T1 is the temperature of the first roasting treatment; t1 is the time of the first roasting treatment; T2 is the temperature of the second roasting treatment; t2 is the time of the second roasting treatment; T3 is the temperature of the third roasting treatment; t3 is the time of the second roasting treatment; and T4 is the roasting temperature in step 3).

[0236] Table 2

[0237]

[0238] In Table 2, FWHM(003) refers to the full width at half maximum (FWHM) of the characteristic peak of the (003) crystal plane; FWHM(104) refers to the full width at half maximum (FWHM) of the characteristic peak of the (104) crystal plane; h1:h2:D0 is the ratio of the thickness of the high-entropy layer, the thickness of the oxygen hole layer and the diameter of the lithium-rich manganese substrate; h3:D0 is the ratio of the thickness of the carbon-nitrogen layer and the diameter of the lithium-rich manganese substrate.

[0239] As can be seen from Table 2, the characteristic peaks of the (003) crystal plane of the lithium-rich manganese-based materials in Examples 1 and Comparative Examples 2-3 are narrower than the characteristic peaks of the (003) crystal plane of the lithium-rich manganese-based materials in Comparative Example 4. The characteristic peaks of the (104) crystal plane of the lithium-rich manganese-based materials in Examples 1 and Comparative Examples 2-3 are also narrower than the characteristic peaks of the (104) crystal plane of the lithium-rich manganese-based materials in Comparative Example 4. This indicates that by doping the lithium-rich manganese-based materials with Mg and Al, the layered structure order, crystallinity, and grain size of the lithium-rich manganese-based materials can be improved, and the lattice strain of the lithium-rich manganese-based materials can be reduced, making the overall structure of the lithium-rich manganese-based materials more complete and stable. Moreover, the I(003) / I(104) ratio of the lithium-rich manganese-based material in Example 1 is higher, indicating that the lithium-rich manganese-based material has better crystallinity and higher grain integrity.

[0240] Table 3

[0241]

[0242] Table 4

[0243]

[0244] As can be seen from Tables 1-4, the lithium-rich manganese-based materials of this application, when applied to batteries, can improve the discharge capacity, cycle performance, and rate performance of the batteries. This application demonstrates that by using a lithium-rich manganese-based matrix comprising M1 (Mg and / or Al) and L (halogen), and by including at least a portion of the surface of the lithium-rich manganese-based matrix with a specific coating layer (the coating layer comprising a carbon-nitrogen layer and a plurality of protrusions comprising a solid electrolyte located on at least a portion of the surface of the carbon-nitrogen layer), a lithium-rich manganese-based material with improved battery electrochemical performance can be obtained.

[0245] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A lithium-rich manganese-based material, characterized in that, The lithium-rich manganese-based material includes a lithium-rich manganese-based matrix and a coating layer located on at least a portion of the surface of the lithium-rich manganese-based matrix; The lithium-rich manganese-based matrix includes the compound shown in Formula 1; (Li2MnO3) x (LiNi a Co b Mn c M1 d M2 e L f O2) y Formula 1 In Equation 1, 0.05≤a≤0.7, 0≤b≤0.6, 0.01≤c≤0.8, 0<d≤0.1, 0<e≤0.1, 0<f≤0.05, 0<x<1, 0<y<1; M1 includes Al and / or Mg, M2 includes at least one element selected from Zr, Nb, Ru, V, Ta, Mo, W, Ti, and Cr, and L includes halogens; The coating layer includes a carbon-nitrogen layer and a plurality of protrusions located on at least a portion of the surface of the carbon-nitrogen layer away from the lithium-rich manganese substrate, the protrusions including a solid electrolyte.

2. The lithium-rich manganese-based material according to claim 1, characterized in that, The lithium-rich manganese-based substrate includes a central core layer, a high-entropy layer, and an oxygen-hole layer; the high-entropy layer is located on at least a portion of the surface of the central core layer, and the oxygen-hole layer is located on at least a portion of the surface of the high-entropy layer away from the central core layer. The oxygen hole layer includes halogens; the high-entropy layer includes at least three of M2, Co, Ni, and Mn, and the high-entropy layer includes at least M2; Preferably, the oxygen cavitation layer includes F; Preferably, the ratio of the thickness of the high-entropy layer, the thickness of the oxygen hole layer, to the diameter of the lithium-rich manganese substrate is 1:(0.01-0.5):(5-200). Preferably, the thickness of the high-entropy layer is 5nm-30nm; and / or, the thickness of the oxygen hole layer is 0.15nm-2.5nm.

3. The lithium-rich manganese-based material according to claim 1 or 2, characterized in that, In the lithium-rich manganese-based material, the content of C is 200ppm-1000ppm; and / or, the content of N is 500ppm-1500ppm; and / or, the content of L is 100ppm-300ppm; and / or, the content of Mg is 400ppm-700ppm; and / or, the content of Al is 500ppm-800ppm. Preferably, M1 is uniformly distributed in the lithium-rich manganese matrix; Preferably, M1 includes Mg and Al.

4. The lithium-rich manganese-based material according to any one of claims 1-3, characterized in that, The ratio of the diameter of the lithium-rich manganese-based substrate to the thickness of the carbon-nitrogen layer is (10-500):1; Preferably, the lithium-rich manganese-based material comprises primary particles with an average particle size of 0.1 μm-0.7 μm; and / or, the lithium-rich manganese-based matrix has an average diameter of 0.1 μm-0.7 μm; and / or, the carbon-nitrogen layer has a thickness of 1 nm-10 nm.

5. The lithium-rich manganese-based material according to any one of claims 1-4, characterized in that, In the lithium-rich manganese-based material, the area coverage of the protruding structure is 10%-50%; and / or, The solid electrolyte comprises at least one of lithium aluminum titanium phosphate, lithium lanthanum zirconium oxide, lithium aluminum silicon titanium phosphate, lithium lanthanum titanium oxide, and lithium lanthanum zirconium tantalum oxide; preferably, the solid electrolyte comprises lithium aluminum titanium phosphate; and / or, The width of the protrusion structure is 0.5nm-3nm; and / or, The maximum height of the protrusion structure is 1nm-30nm; and / or, The spacing D between two adjacent protrusions satisfies: 0 < D ≤ 300 nm.

6. The lithium-rich manganese-based material according to any one of claims 1-5, characterized in that, The span of the secondary particles of the lithium-rich manganese-based material is 0.8-1.5; and / or, The secondary particles of the lithium-rich manganese-based material have a Dv50 of 1μm-5μm; preferably, the secondary particles of the lithium-rich manganese-based material have a Dv50 of 3μm-4μm.

7. The lithium-rich manganese-based material according to any one of claims 1-6, characterized in that, The specific surface area of ​​the lithium-rich manganese-based material is 1m². 2 / g-4m 2 / g; and / or, The powder conductivity of the lithium-rich manganese-based material is ≥1. 10 -7 S / cm; and / or, The surface LiOH content of the lithium-rich manganese-based material is <500ppm; and / or, The surface Li2CO3 content of the lithium-rich manganese-based material is <800ppm.

8. The lithium-rich manganese-based material according to any one of claims 1-7, characterized in that, In the X-ray diffraction pattern of the lithium-rich manganese-based material, there are characteristic peaks on the (003) plane with 2θ of 18.4°-18.5° and characteristic peaks with 2θ of 26.7°-27.1°; and / or, The X-ray diffraction pattern of the lithium-rich manganese-based material exhibits a characteristic peak with a 2θ value of 29.3°–29.6°; and / or, In the X-ray diffraction pattern of the lithium-rich manganese-based material, the full width at half maximum (FWHM) of the characteristic peak on the (003) plane is 0.13-0.149; and / or, In the X-ray diffraction pattern of the lithium-rich manganese-based material, the intensity I of the characteristic peak of the (003) surface is... （003） The intensity I of the characteristic peak of the (104) surface （104） The ratio of I （003） / I （104） It is 1.78-1.

9.

9. A lithium-ion secondary battery, comprising a positive electrode sheet, the positive electrode sheet comprising a positive current collector and a positive active layer disposed on at least one surface of the positive current collector in the thickness direction, the positive active layer comprising a positive active material, characterized in that, The positive electrode active material includes the lithium-rich manganese-based material according to any one of claims 1-8.

10. The lithium-ion secondary battery according to claim 9, characterized in that, The lithium-ion secondary battery includes any one of the following: all-solid-state battery, semi-solid-state battery, and liquid battery.

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