Modified lithium-rich manganese-based material, method for modifying lithium-rich manganese-based material, secondary battery, and electric device

Abstract

The application provides a modified lithium-rich manganese-based material, a modification method of the lithium-rich manganese-based material, a secondary battery and an electric device. The modified lithium-rich manganese-based material comprises a lithium-rich manganese-based material co-doped with anions and cations and a fast ion conductor material, and a chemical formula of the lithium-rich manganese-based material is xLi2MnO3·(1-x)LiNi y Co z Mn a O2, wherein 0

Description

Technical Field

[0001] This application relates to the technical field of batteries, and particularly to a modified lithium-rich manganese-based material, a modification method of the lithium-rich manganese-based material, a secondary battery, and an electrical device. Background Art

[0002] The cathode material is the most critical component of a lithium-ion battery. It is the source of Li+ in the lithium-ion battery, directly determining its energy density, and is also an important factor affecting the battery's power density, cycle life, and safety performance. The lithium-rich manganese-based layered cathode material first proposed by Dahn and his colleagues and Thackeray et al. has advantages such as a high discharge specific capacity above 250 mAh / g and a high energy density, and is regarded as the main material for the next generation of power batteries.

[0003] When the lithium-rich manganese-based material is charged at a high voltage above 4.5V in the first cycle, some lithium ions in the transition metal layer will be removed together with oxygen to form Li2O and escape. These crystal vacancies are difficult to accept lithium ions again during subsequent charge and discharge processes, resulting in a low first charge-discharge efficiency of the material; at the same time, the formation of a large number of oxygen vacancies causes the migration of transition metal ions, leading to a rearrangement of the crystal structure, resulting in instability of the material structure, and further causing poor cycling performance. In addition, due to the low electronic and ionic conductivities of the lithium-rich material itself, and the aggravation of the side reaction between the material surface and the electrolyte at high voltages, the rate performance of the material is extremely poor. Summary of the Invention

[0004] This application provides a modified lithium-rich manganese-based material, a modification method of the lithium-rich manganese-based material, a secondary battery, and an electrical device to solve the problem of poor rate performance of the lithium-rich manganese-based material.

[0005] In the first aspect of the present invention, a modified lithium-rich manganese-based material is provided. The modified lithium-rich manganese-based material includes a lithium-rich manganese-based material co-doped with cations and anions. The chemical formula of the lithium-rich manganese-based material is xLi2MnO3·(1-x)LiNi y Co z Mn a O2, where 0 < x < 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1, and y + z + a = 1; the doped cationic element M1 is selected from one or more of the group consisting of Na, Fe, Nb, Ti, Mg, Al, Cr, and Er, and the doped anionic element M2 is selected from one or more of the group consisting of F, Cl, Br, I, S, B, P, N, Se, and Te;

[0006] Fast ion conductor material, which is attached to the lithium-rich manganese-based material co-doped with anions and cations, wherein the fast ion conductor material is selected from one or more of the group consisting of LATP (lithium aluminum titanium phosphate), LAGP (lithium aluminum germanium phosphate), LLZO (lithium lanthanum zirconate), LLTO (lithium lanthanum titanate), LiBO2 (lithium borate), LiAlO2 (lithium aluminate), and LiPO3 (lithium metaphosphate).

[0007] In the modified lithium-rich manganese-based material of this application, anion doping mainly replaces oxygen sites in the lithium-rich manganese-based cathode material. At high potentials, this suppresses excessive oxidation of lattice oxygen, alleviates lattice oxygen loss, reduces oxygen release during the first cycle, mitigates electrolyte decomposition, and improves the material's initial efficiency. Cation doping mainly replaces transition metal sites in the lithium-rich manganese-based material. During charge and discharge, this stabilizes the crystal structure, increases the formation energy of oxygen vacancies, and inhibits the material's transformation to a spinel structure, thereby improving cycle stability and thermal stability. Fast ion conductor materials, as a so-called coating layer in the art, effectively improve the ionic conductivity of lithium-rich manganese-based materials, increase the lithium-ion transport rate, and enhance the material's rate performance and capacity. Simultaneously, fast ion conductor materials are stable, effectively reducing side reactions between the material and the electrolyte under high potential conditions, improving the material's storage capacity, and reducing gas generation.

[0008] In any embodiment of the first aspect, the doping amount of M1 / M2 is 1:(0.3 to 2), and can be selected as 1:(0.5 to 1.5); in order to improve the synergistic effect of anion and cation doping, so as to improve the cycle performance and first efficiency of the material to the greatest extent possible.

[0009] In any embodiment of the first aspect, when the doped cation element M1 is Fe, the doped anion element M2 is Cl; or when the doped cation element M1 is Na, the doped anion element M2 is F. The above-mentioned combination of cation and anion doping is particularly effective in modifying lithium-rich manganese-based materials.

[0010] In any embodiment of the first aspect, the doping amount of the cation element M1 is 1000–20000 ppm, optionally 2000–10000 ppm; the doping amount of the anion element M2 is 300–40000 ppm, optionally 1000–20000 ppm, to further improve the effect of cation and anion doping modification.

[0011] In any embodiment of the first aspect, the weight content of the fast ion conductor material in the modified lithium-rich manganese-based material is 2000–20000 ppm, optionally 2000–10000 ppm. The fast ion conductor material is uniformly distributed in an island-like or dot-like pattern on the surface of the cathode material, effectively improving the conductivity of the lithium-rich manganese-based material.

[0012] In any embodiment of the first aspect, the conductivity of the modified lithium-rich manganese-based material is 10–60 μS / cm, preferably 30–60 μS / cm. After modification with a fast-ion conductor material, the conductivity of the modified lithium-rich manganese-based material increases compared to the anion-cation co-doped lithium-rich manganese-based material.

[0013] In any embodiment of the first aspect, the specific surface area of ​​the modified lithium-rich manganese-based material is <3.2 m². 2 / g, which can be selected from 0.3 to 2.2m 2 / g. The modified lithium-rich manganese-based material has a low specific surface area, thus ensuring excellent cycle performance. Optionally, the primary particle size of the modified lithium-rich manganese-based material is D... V50 The D-value of primary particles modified from fast ion conductor materials is 100–300 nm. V50 Compared to the unmodified lithium-rich manganese-based material with co-doped anions and cations, the size of the material is reduced, while the specific surface area is increased. Channels that facilitate lithium-ion diffusion are formed on the surface, resulting in a significant improvement in the first-efficiency and rate performance of the lithium-rich manganese-based material.

[0014] In any embodiment of the first aspect, the volumetric particle size distribution of the modified lithium-rich manganese-based material satisfies (Dv90-Dv10) / Dv50 ≥ 1.1; optionally, it satisfies (Dv90-Dv10) / Dv50 ≥ 1.2; optionally, the powder compaction density of the modified lithium-rich manganese-based material under 5 tons of pressure is ≥ 3.0 g / cc. When the modified lithium-rich manganese-based material has a large particle size distribution and / or a large compaction density, the modified lithium-rich manganese-based material has a high volumetric energy density.

[0015] In any embodiment of the first aspect, in the X-ray diffraction pattern of the modified lithium-rich manganese-based material, the peak area ratio of I003 / I104 is 1.0 to 1.2, optionally 1.05 to 1.15; the peak area ratio of I020 / (I003+I104) is 0.005 to 0.05, optionally 0.008 to 0.02. The peak area ratio of I003 / I104 being controlled within the above range indicates a low degree of lithium-nickel mixing in the material and good structural stability; the peak area ratio of I020 / (I003+I104) being controlled within the above range indicates that the lithium-rich phase is controlled in a relatively optimal proportion, resulting in good first-efficiency and cycle performance of the material.

[0016] In any embodiment of the first aspect, the 003 and 104 characteristic peaks of the modified lithium-rich manganese-based material are shifted to the left relative to the 003 and 104 characteristic peaks of the lithium-rich manganese-based material, indicating that the lithium interlayer spacing and cell volume are expanded by anion and cation doping, which is more conducive to ion diffusion.

[0017] A second aspect of this application provides a method for modifying lithium-rich manganese-based materials, the method comprising:

[0018] Step S1: Perform first sintering on the first mixture. The first mixture includes a lithium-rich manganese-based precursor, a lithium salt, a substance containing cationic element M1, and a substance containing anionic element M2, to obtain a lithium-rich manganese-based material co-doped with cations and anions. The chemical formula of the lithium-rich manganese-based material is xLi2MnO3·(1-x)LiNi y Co z Mn a O2, where 0 < x < 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1, and y + z + a = 1; the cationic element M1 is selected from one or more of the group consisting of Na, Fe, Nb, Ti, Mg, Al, Cr, and Er, and the anionic element M2 is selected from one or more of the group consisting of F, Cl, Br, I, S, B, P, N, Se, and Te, and the mass of the cationic element M1 to the anionic element M2 is 1:(0.3 - 2);

[0019] S2: Perform second sintering on the second mixture including the fast ion conductor material and the lithium-rich manganese-based material co-doped with cations and anions, to obtain a modified lithium-rich manganese-based material. The modified lithium-rich manganese-based material includes the lithium-rich manganese-based material co-doped with cations and anions and the fast ion conductor material. The fast ion conductor material is selected from one or more of the group consisting of LATP (lithium aluminum titanium phosphate), LAGP (lithium germanium aluminum phosphate), LLZO (lithium lanthanum zirconate), LLTO (lithium lanthanum titanate), LiBO2 (lithium borate), LiAlO2 (lithium aluminate), LiPO3 (metaphosphoric acid lithium).

[0020] The modification method of the present application, especially the fast ion conductor material is directly coated on the lithium-rich manganese-based material co-doped with cations and anions by the solid-phase method. Compared with the in-situ coating method, the coating method is simple and easy to implement, has high efficiency, low cost, has no strict requirements for the coating temperature, is easy to realize large-scale production, and the fast ion conductor material shows an island-like or dot-like distribution on the surface layer of the cathode material. The synthesized lithium-rich manganese-based material obtained by modification has regular morphology, high crystallinity, relatively high capacity, excellent rate and cycling performance. At the same time, the fast ion conductor material has stable properties, effectively reduces the side reaction between the material and the electrolyte under high potential conditions, improves the storage of the material, and reduces the gas generation of the material.

[0021] In any implementation manner of the second aspect, the chemical formula of the above lithium-rich manganese-based precursor is Ni b Co c Mn 1-b-c(OH)₂, wherein 0.05 ≥ c ≥ 0, 0.4 ≥ b > 0; optionally, the lithium salt is one or more of lithium hydroxide, lithium carbonate, or lithium acetate; optionally, the molar ratio of the sum of transition metal elements in the lithium-rich manganese-based precursor to lithium in the lithium salt is 1:(1.1–1.8), preferably 1:(1.1–1.5). The above-mentioned lithium-rich manganese-based precursor has a high Mn content and a low Co content, which is beneficial for reducing raw material costs.

[0022] In any embodiment of the second aspect, the substance containing the cation element M1 is an oxide or salt of M1; optionally, the substance containing the anionic element M2 is an element, a salt, or an organic compound. The substances from the above sources are widely available and have low cost.

[0023] In any embodiment of the second aspect, the mass ratio of M1 to the lithium-rich manganese-based material in the substance containing the cationic element M1 is 1000–20000 ppm, more preferably 2000–10000 ppm; optionally, the mass ratio of M2 to the lithium-rich manganese-based material in the substance containing the anionic element M2 is 300–40000 ppm, more preferably 1000–20000 ppm. By controlling the above mass ratios, the doping amounts of the anions and cations are kept within a preset range so that they can synergistically exert their effects.

[0024] In any embodiment of the second aspect, the mass ratio of the fast ion conductor to the lithium-rich manganese-based material co-doped with anions and cations is 2000 to 20000 ppm, optionally 2000 to 10000 ppm, to achieve effective and appropriate coating of the core.

[0025] In any embodiment of the second aspect, the first sintering includes a first-stage sintering process and a second-stage sintering process, wherein the sintering temperature of the first-stage sintering process is 400–600°C and the holding time is 4–8 h; the sintering temperature of the second-stage sintering process is 800–1000°C and the holding time is 10–20 h. Utilizing the above two-stage sintering process results in a lithium-rich manganese-based material with high crystallinity and low spinel impurity content obtained after sintering, doped with anions and cations.

[0026] In any embodiment of the second aspect, the sintering temperature of the second sintering is 500-700°C and the holding time is 4-8 hours, which further optimizes the uniformity and firmness of the fast ion conductor material coating.

[0027] A third aspect of this application provides a secondary battery, including a positive electrode, a separator, and a negative electrode. The positive electrode includes a positive electrode film layer, which includes a positive electrode active material. The positive electrode active material comprises any of the modified lithium-rich manganese-based materials described above, or a modified lithium-rich manganese-based material obtained by any of the modification methods described above. The secondary battery provided by this application exhibits high initial efficiency, good cycle performance and rate performance, and low gas production.

[0028] A third aspect of this application provides an electrical device including a secondary battery, wherein the secondary battery is selected from the aforementioned secondary batteries. The electrical device having the secondary battery of this application exhibits better electrical performance and more stable operation. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0030] Figure 1 The image shows a scanning electron microscope (SEM) image of the primary particles of the lithium-rich manganese-based cathode material before and after LATP coating in Example 1.

[0031] Figure 2 The XRD diffraction pattern of the lithium-rich manganese-based cathode material co-doped with LATP in Example 1 is shown.

[0032] Figure 3 The XRD diffraction patterns of local 003 and 104 diffraction peaks of the lithium-rich manganese-based cathode material before and after anion and cation co-doping in Example 1 are shown.

[0033] Figure 4 This is a schematic diagram of a secondary battery according to one embodiment of this application.

[0034] Figure 5 yes Figure 4 An exploded view of a secondary battery according to one embodiment of this application is shown.

[0035] Figure 6 This is a schematic diagram of a battery module according to one embodiment of this application.

[0036] Figure 7 This is a schematic diagram of a battery pack according to one embodiment of this application.

[0037] Figure 8 yes Figure 7 An exploded view of a battery pack according to one embodiment of this application is shown.

[0038] Figure 9 This is a schematic diagram of an electrical device that uses a secondary battery as a power source according to one embodiment of this application.

[0039] The accompanying drawings are not drawn to scale.

[0040] Explanation of reference numerals in the attached figures:

[0041] 1 Battery pack; 2 Upper housing; 3 Lower housing; 4 Battery module; 5 Secondary battery; 51 Housing; 52 Electrode assembly; 53 Top cover assembly. Detailed Implementation

[0042] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0043] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the modified lithium-rich manganese-based material, the modification method of the lithium-rich manganese-based material, the secondary battery, and the power supply device of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0044] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60–120 and 80–110 are listed for a specific parameter, it is understood that ranges of 60–110 and 80–120 are also expected. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5. In this application, unless otherwise stated, the numerical range "a–b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0045] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0046] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0047] Unless otherwise specified, all steps of this application can be carried out in sequence or randomly, preferably in sequence. For example, when the method includes steps (a) and (b), it means that the method can include steps (a) and (b) carried out in sequence, or steps (b) and (a) carried out in sequence. For example, when it is mentioned that the method further includes step (c), it means that step (c) can be added to the method in any order. For example, the method can include steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0048] Unless otherwise specified, the terms "comprising" and "including" mentioned in this application mean open-ended, and can also be closed-ended. For example, the "comprising" and "including" can mean that other components not listed can also be included or contained, or it can only include or contain the listed components.

[0049] Unless otherwise specified, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) while B is true (or exists); or both A and B are true (or exist).

[0050] [Modified lithium-rich manganese-based material]

[0051] The first aspect of the present invention provides a modified lithium-rich manganese-based material, which includes a lithium-rich manganese-based material co-doped with cations and anions and a fast ion conductor material, and the fast ion conductor material is attached to the lithium-rich manganese-based material co-doped with cations and anions;

[0052] The chemical formula of the lithium-rich manganese-based material is xLi2MnO3·(1-x)LiNi y Co z Mn a O2, where 0 < x < 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1, and y + z + a = 1; the doped cationic element M1 is selected from one or more of the group consisting of Na, Fe, Nb, Ti, Mg, Al, Cr and Er, and the doped anionic element M2 is selected from one or more of the group consisting of F, Cl, Br, I, S, B, P, N, Se and Te;

[0053] The fast ion conductor material is selected from one or more of the group consisting of LATP (lithium aluminum titanium phosphate), LAGP (lithium germanium aluminum phosphate), LLZO (lithium lanthanum zirconate), LLTO (lithium lanthanum titanate), LiBO2 (lithium borate), LiAlO2 (lithium aluminate), and LiPO3 (lithium metaphosphate).

[0054] In the modified lithium-rich manganese-based material of this application, anion doping mainly replaces oxygen sites in the lithium-rich manganese-based cathode material. At high potentials, this suppresses excessive oxidation of lattice oxygen, alleviates lattice oxygen loss, reduces oxygen release during the first cycle, mitigates electrolyte decomposition, and improves the material's initial efficiency. Cation doping mainly replaces transition metal sites in the lithium-rich manganese-based material. During charge and discharge, this stabilizes the crystal structure, increases the formation energy of oxygen vacancies, further alleviates lattice oxygen loss, and inhibits the material's transformation to a spinel structure, thereby improving cycle stability and thermal stability. Fast ion conductor materials, as a so-called coating layer in the art, effectively improve the ionic conductivity of lithium-rich manganese-based materials, increase the lithium-ion transport rate, and enhance the material's rate performance and capacity. Simultaneously, fast ion conductor materials are stable, effectively reducing side reactions between the material and the electrolyte under high potential conditions, improving material storage capacity, and reducing gas generation.

[0055] The doping amounts of the aforementioned cations and anions each have their own functions. In some embodiments, the doping amount of M1 / M2 is 1:(0.3-2), optionally 1:(0.5-1.5), to improve the synergistic effect of cation and anion doping and maximize the improvement of the material's cycle performance and first-efficiency. In some embodiments, the doping amount of M1 / M2 can be 1:0.3, 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, or 1:2.

[0056] The aforementioned doped cations and anions can all alleviate lattice oxygen loss and increase the oxygen vacancy formation energy, but their respective effects vary depending on the elemental composition and properties. For example, when the doped cation M1 is Fe, the doped anion M2 is Cl; or when the doped cation M1 is Na, the doped anion M2 is F. This is mainly because Cl and F have a stronger binding force on transition metal elements than O, which can reduce the solubility of transition metal elements in the electrolyte, stabilize the structure of lithium-rich manganese-based materials, and reduce oxygen release. In addition, the doping of Cl and F can further reduce the average valence state of transition metals, and the reversible capacity of the battery will also be improved. On the other hand, Na and Fe occupy the transition metal layer and have a stronger binding energy with O, further alleviating lattice oxygen loss, and Fe can undergo Fe2+ oxidation during charge-discharge cycles. 3+ To Fe 4+ The transformation further enhances the material's capacity. Therefore, by using specific combinations of Fe and Cl, Na and F, the transition metal layer and oxygen layer of the material are reinforced respectively, with particularly outstanding modification effects on lithium-rich manganese-based materials.

[0057] The cationic element M1 and the anionic element M2 are used as doping elements. While ensuring that the basic crystal structure of the lithium-rich manganese-based material is not affected, increasing their doping amount helps to mitigate lattice oxygen loss. Simultaneously, to further ensure sufficient oxygen vacancies to meet the needs of rapid lithium-ion insertion and extraction, in some embodiments, the doping amount of the aforementioned cationic element M1 is 1000–20000 ppm, optionally 2000–10000 ppm, such as 1000 ppm, 2000 ppm, 5000 ppm, 8000 ppm, 1000 ppm, etc. 00ppm, 12000ppm, 15000ppm, 18000ppm or 20000ppm; the doping amount of the anionic element M2 is 300 to 40000ppm, which can be selected from 1000 to 20000ppm, such as 300ppm, 500ppm, 800ppm, 1000ppm, 1500ppm, 2000ppm, 5000ppm, 8000ppm, 10000ppm, 20000ppm or 40000ppm to further improve the effect of anion and cation doping modification.

[0058] In some embodiments, the weight content of fast ion conductor material in the modified lithium-rich manganese-based material is 2000–20000 ppm, optionally 2000–10000 ppm, such as 2000 ppm, 5000 ppm, 8000 ppm, 10000 ppm, 15000 ppm, or 20000 ppm. The fast ion conductor material is uniformly distributed in an island-like or dot-like pattern on the surface of the cathode material, effectively improving the conductivity of the lithium-rich manganese-based material.

[0059] The preferred morphology of the modified lithium-rich manganese-based material is secondary spheres, single crystals, or near-single crystals. Experiments revealed that after modifying the anion-cation co-doped lithium-rich manganese-based material with fast ion conductor coating, the primary particle size decreased and the specific surface area increased. For example, the specific surface area of ​​the material before fast ion conductor coating, i.e., the anion-cation co-doped lithium-rich manganese-based material, was <3.0 μm. 2 / g, 0.1~2m can be selected. 2 / g; the preferred particle size is 1–20 μm, optionally 3–15 μm, and the thickness of the primary particles is 300–500 nm. The specific surface area of ​​the modified lithium-rich manganese-based material obtained after coating with fast ion conductor material is <3.2 m². 2 / g, which can be selected from 0.3 to 2.2m 2 / g. The modified lithium-rich manganese-based material has a low specific surface area, thus ensuring excellent cycle performance. Optionally, the thickness of the primary particles in the modified lithium-rich manganese-based material is 100–300 nm. The thickness of the primary particles after modification with fast ion conductor material is relatively smaller than that of the unmodified anion-cation co-doped lithium-rich manganese-based material, resulting in a larger specific surface area. This forms channels on the surface that facilitate lithium-ion diffusion, significantly improving the first-stage efficiency and rate performance of the lithium-rich manganese-based material.

[0060] Specific surface area is a well-known term in the art and can be tested using methods known in the art. For example, it can be tested using the nitrogen adsorption specific surface area analysis method according to GB / T 19587-2017, and calculated using the BET (Brunauer Emmett Teller) method. The nitrogen adsorption specific surface area analysis can be performed using the Tri-Star 3020 specific surface area and pore size analyzer from Micromeritics, Inc., USA.

[0061] In some embodiments, the volumetric particle size distribution of the modified lithium-rich manganese-based material satisfies (Dv90-Dv10) / Dv50 ≥ 1.1; optionally, it satisfies (Dv90-Dv10) / Dv50 ≥ 1.2; optionally, the powder compaction density of the modified lithium-rich manganese-based material at 5 tons of pressure is ≥ 3.0 g / cc. When the modified lithium-rich manganese-based material has a larger particle size distribution and / or a larger compaction density, it has a higher volumetric energy density. Dv50 refers to the particle size corresponding to 50% of the volumetric distribution, and Dv10 and Dv90 are deduced accordingly. As an example, Dv50 can be conveniently determined using a laser particle size analyzer, such as the Mastersizer 2000E laser particle size analyzer from Malvern Instruments Ltd., UK, according to GB / T 19077-2016 Particle Size Distribution Laser Diffraction Method.

[0062] When the modified lithium-rich manganese-based material contains the aforementioned doping elements, its crystal structure also undergoes certain changes compared to the undoped state. In some embodiments, in the X-ray diffraction pattern of the modified lithium-rich manganese-based material, the peak area ratio of I003 / I104 is 1.0–1.2, optionally 1.05–1.15; the peak area ratio of I020 / (I003+I104) is 0.005–0.05, optionally 0.008–0.02. The peak area ratio of I003 / I104 being controlled within the above range indicates a low degree of lithium-nickel mixing in the material and good structural stability; the peak area ratio of I020 / (I003+I104) being controlled within the above range indicates that the lithium-rich phase is controlled in a relatively optimal proportion, resulting in better first-efficiency and cycle performance of the material.

[0063] In any embodiment of the first aspect, the 003 characteristic peak and the 104 characteristic peak of the modified lithium-rich manganese-based material are shifted to the left relative to the 003 characteristic peak and the 104 characteristic peak of the lithium-rich manganese-based material, indicating that the lithium layer spacing and the unit cell volume are enlarged by cation and anion doping, which is more conducive to ion diffusion.

[0064] Another embodiment of the present application provides a modification method for a lithium-rich manganese-based material, the modification method comprising:

[0065] Step S1: subjecting a first mixture to a first sintering, the first mixture comprising a lithium-rich manganese-based precursor, a lithium salt, a substance containing a cationic element M1, and a substance containing an anionic element M2, to obtain a lithium-rich manganese-based material co-doped with cations and anions, wherein the chemical formula of the lithium-rich manganese-based material is xLi2MnO3·(1-x)LiNi y Co z Mn a O2, where 0 < x < 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1, and y + z + a = 1; the cationic element M1 is selected from one or more of the group consisting of Na, Fe, Nb, Ti, Mg, Al, Cr, and Er, and the anionic element M2 is selected from one or more of the group consisting of F, Cl, Br, I, S, B, P, N, Se, and Te, and the mass of the cationic element M1 and the anionic element M2 satisfies 1:(0.3 - 2);

[0066] S2: subjecting a second mixture comprising a fast ion conductor material and a lithium-rich manganese-based material co-doped with cations and anions to a second sintering to obtain a modified lithium-rich manganese-based material, the modified lithium-rich manganese-based material comprising a lithium-rich manganese-based material co-doped with cations and anions and a fast ion conductor material, the fast ion conductor material being selected from one or more of the group consisting of LATP (lithium aluminum titanium phosphate), LAGP (lithium germanium aluminum phosphate), LLZO (lithium lanthanum zirconate), LLTO (lithium lanthanum titanate), LiBO2 (lithium borate), LiAlO2 (lithium aluminate), and LiPO3 (lithium metaphosphate).

[0067] In the modification method of the present application, especially the fast ion conductor material is directly coated on the lithium-rich manganese-based material co-doped with cations and anions by the solid-phase method. Compared with the in-situ coating method, the coating method is simple and easy to implement, has high efficiency, low cost, has no strict requirements for the coating temperature, is easy to achieve large-scale production, and the fast ion conductor material shows an island-like or dot-like distribution on the surface layer of the cathode material. The synthesized lithium-rich manganese-based material obtained by modification has regular morphology, high crystallinity, relatively high capacity, excellent rate and cycling performance. At the same time, the fast ion conductor material has stable properties, effectively reduces the side reaction between the material and the electrolyte under high potential conditions, improves the storage of the material, and reduces the gas generation of the material.

[0068] In some embodiments, the chemical formula of the above lithium-rich manganese-based precursor is Nib Co c Mn 1-b-c (OH)2, wherein 0.05≥b≥0, 0.4≥c>0; the above-mentioned lithium-rich manganese-based precursor has a high Mn content and a low Co content, which is beneficial to reducing raw material costs. The lithium salt used in the above modification method can be a lithium salt commonly used in the art for preparing lithium cathode materials. To save costs, the lithium salt can optionally be one or more of lithium hydroxide, lithium carbonate, or lithium acetate. In order to further increase the lithium content in the obtained lithium-rich manganese-based material, in some embodiments, the molar ratio of the sum of transition metal elements in the lithium-rich manganese-based precursor to lithium in the lithium salt is controlled to be 1:(1.1~1.8), preferably 1:(1.1~1.5).

[0069] The aforementioned cation element M1 and anion element M2 can be derived from various known substances with relatively stable properties. In some embodiments, the substance containing cation element M1 is an oxide or salt of M1, etc.; optionally, the substance containing anion element M2 is an element, salt, or organic compound, etc. The aforementioned sources of substances are widely available and have low costs.

[0070] In some embodiments, the mass ratio of the cationic element M1 to the lithium-rich manganese-based material is 1000–20000 ppm, more preferably 2000–10000 ppm; optionally, the mass ratio of the anionic element M2 to the lithium-rich manganese-based material is 300–40000 ppm, more preferably 1000–20000 ppm. By controlling the above mass ratios, the doping amounts of the cations and anions are kept within a preset range so that they can synergistically enhance each other.

[0071] In some embodiments, the mass ratio of the fast ion conductor to the lithium-rich manganese-based material co-doped with anions and cations is 2000 to 20000 ppm, optionally 2000 to 10000 ppm, to achieve effective and appropriate coating of the core.

[0072] The first and second sintering processes described above can refer to the sintering processes commonly used in the preparation of lithium-rich manganese-based materials in the prior art, such as sintering in air or sintering in oxygen-rich gas.

[0073] In some embodiments, to ensure the stable entry of doped cations and anions into the crystal lattice and to maintain the lithium-rich manganese-based matrix structure, the first sintering process includes a first-stage sintering process and a second-stage sintering process. The first-stage sintering process is carried out at a temperature of 400–600°C for 4–8 hours; the second-stage sintering process is carried out at a temperature of 800–1000°C for 10–20 hours. This two-stage sintering process results in a high crystallinity and a low spinel impurity content in the sintered lithium-rich manganese-based material doped with cations and anions.

[0074] In some embodiments, the sintering temperature of the second sintering is 500-700°C and the holding time is 4-8 hours, which further optimizes the uniformity and firmness of the fast ion conductor material coating.

[0075] [Rechargeable Battery]

[0076] Secondary batteries, also known as rechargeable batteries or storage batteries, are batteries that can be recharged after being discharged to activate the active materials and continue to be used.

[0077] Typically, a secondary battery consists of a positive electrode, a negative electrode, a separator, and an electrolyte. During charging and discharging, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, primarily prevents short circuits while allowing active ions to pass through. The electrolyte, also positioned between the positive and negative electrodes, mainly serves to conduct active ions.

[0078] [Positive electrode plate]

[0079] A positive electrode typically includes a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector, the positive electrode film layer including a positive active material.

[0080] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0081] In some embodiments, the positive current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0082] The positive electrode active material in the secondary battery of this application includes any of the modified lithium-rich manganese-based materials described above or modified lithium-rich manganese-based materials obtained by any of the modification methods described above. Based on the modified lithium-rich manganese-based material of this application, the secondary battery exhibits high initial efficiency, good cycle performance and rate performance, and low gas production.

[0083] In some embodiments, the positive electrode active material may also be a known positive electrode active material for batteries. As an example, the positive electrode active material may include at least one of the following materials: lithium phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Examples of lithium phosphates with an olivine structure include, but are not limited to, lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0084] In some embodiments, the positive electrode film layer may optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0085] In some embodiments, the positive electrode film may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0086] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0087] [Negative electrode plate]

[0088] The negative electrode sheet includes a negative current collector and a negative electrode film layer disposed on at least one surface of the negative current collector, the negative electrode film layer including a negative electrode active material.

[0089] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0090] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0091] In some embodiments, the negative electrode active material may be a negative electrode active material known in the art for use in batteries. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0092] In some embodiments, the negative electrode film layer may optionally include a binder. As an example, the binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0093] In some embodiments, the negative electrode film may optionally include a conductive agent. As an example, the conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0094] In some embodiments, the negative electrode film may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0095] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as the negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing and other processes.

[0096] [Electrolytes]

[0097] The electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific restrictions on the type of electrolyte; it can be selected according to requirements. For example, the electrolyte can be liquid, gel, or entirely solid.

[0098] In some embodiments, the electrolyte is liquid and includes an electrolyte salt and a solvent.

[0099] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0100] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0101] In some embodiments, the electrolyte may optionally include additives. As examples, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.

[0102] [Isolation membrane]

[0103] In some embodiments, the secondary battery also includes a separator. This application does not impose any particular limitation on the type of separator; any known porous separator with good chemical and mechanical stability can be selected.

[0104] In some embodiments, the material of the separator can be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0105] In some implementations, the positive electrode, negative electrode, and separator can be fabricated into an electrode assembly using a winding or stacking process.

[0106] In some embodiments, the secondary battery may include an outer packaging. This outer packaging may be used to encapsulate the electrode assembly and electrolyte described above.

[0107] In some embodiments, the outer packaging of the secondary battery can be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The outer packaging of the secondary battery can also be a soft pack, such as a pouch. The material of the soft pack can be plastic; examples of plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0108] This application does not impose any particular limitation on the shape of the secondary battery; it can be cylindrical, square, or any other arbitrary shape. For example, Figure 4 This is an example of a square-structured secondary battery 5.

[0109] In some implementations, refer to Figure 5 The outer packaging may include a housing 51 and a cover 53. The housing 51 may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover 53 can be placed over the opening to close the receiving cavity. A positive electrode, a negative electrode, and a separator can be formed into an electrode assembly 52 using a winding or stacking process. The electrode assembly 52 is encapsulated within the receiving cavity. Electrolyte is immersed in the electrode assembly 52. ​​The secondary battery 5 may contain one or more electrode assemblies 52, which can be selected by those skilled in the art according to specific practical needs.

[0110] In some implementations, the secondary batteries can be assembled into a battery module, and the number of secondary batteries contained in the battery module can be one or more, the specific number of which can be selected by those skilled in the art according to the application and capacity of the battery module.

[0111] Figure 6 This is battery module 4, used as an example. (See reference...) Figure 6 In battery module 4, multiple secondary batteries 5 can be arranged sequentially along the length of battery module 4. Of course, they can also be arranged in any other manner. Furthermore, these multiple secondary batteries 5 can be fixed in place using fasteners.

[0112] Optionally, the battery module 4 may also include a housing with a receiving space in which a plurality of secondary batteries 5 are received.

[0113] In some embodiments, the battery modules described above can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, the specific number of which can be selected by those skilled in the art according to the application and capacity of the battery pack.

[0114] Figure 7 and Figure 8 This is battery pack 1 as an example. (See reference...) Figure 7 and Figure 8 The battery pack 1 may include a battery box and multiple battery modules 4 disposed within the battery box. The battery box includes an upper body 2 and a lower body 3, with the upper body 2 covering the lower body 3 to form a closed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery box.

[0115] In addition, this application also provides an electrical device, which includes at least one of the secondary battery, battery module, or battery pack provided in this application. The secondary battery, battery module, or battery pack can be used as a power source for the electrical device, or as an energy storage unit for the electrical device. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0116] As the electrical device, a secondary battery, battery module, or battery pack can be selected according to its usage requirements.

[0117] Figure 9This is an example of an electrical device. The device could be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the high power and high energy density requirements of the secondary battery for this device, a battery pack or battery module can be used.

[0118] [Example]

[0119] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0120] Example 1

[0121] Ni precursor 0.3 Co 0.05 Mn 0.65 (OH)₂, lithium carbonate, iron oxide, and ammonium chloride were mixed in a plow mixer. Lithium carbonate and the precursor were weighed with a Li / Me (representing transition metals Ni, Co, and Mn) molar ratio of 1.38. The mass ratio of iron to the theoretical lithium-rich manganese-based material was 2000 ppm, and the mass ratio of chlorine to the theoretical lithium-rich manganese-based material was also 2000 ppm. The mixture was then sintered in a kiln at 400℃ for 4 hours, followed by heating to 900℃ and holding for 12 hours. The sintering atmosphere was air. This yielded a co-doped lithium-rich manganese-based cathode material. The obtained lithium-rich manganese-based cathode material was then mixed with LATP and sintered at a mass ratio of 7000 ppm to the co-doped lithium-rich manganese-based cathode material. The sintering temperature was 650℃, and the sintering time was 5 hours, yielding a modified lithium-rich manganese-based cathode material 0.35Li₂MnO₃·0.65LiNi. 0.46 Co 0.08 Mn 0.46 O2, i.e., LATP coated in Fe and Cl co-doped 0.35Li2MnO3·0.65LiNi 0.46 Co 0.08 Mn 0.46 O2 surface. SEM measurements were performed on the lithium-rich manganese-based cathode material before and after LATP coating, and XRD measurements were performed on the lithium-rich manganese-based cathode material before and after cation and anion co-doping. The test results are shown in [Figure number missing]. Figures 1 to 3 .

[0122] Example 2

[0123] The difference from Example 1 is that the doping elements are changed, with the anion element being F provided by lithium fluoride and the cation element being Na provided by sodium carbonate, resulting in a modified lithium-rich manganese-based cathode material 0.35Li₂MnO₃·0.65LiNi. 0.46 Co 0.08 Mn 0.46 O2 and LATP adhere to Na and F co-doped 0.35Li2MnO3·0.65LiNi 0.46 Co 0.08 Mn 0.46 O2 surface.

[0124] Example 3

[0125] The difference from Example 1 is that the doping elements are changed, with the anion element being F provided by lithium fluoride and the cation element being Fe provided by iron oxide, resulting in a modified lithium-rich manganese-based cathode material 0.35Li₂MnO₃·0.65LiNi. 0.46 Co 0.08 Mn 0.46 O2 and LATP adhere to Fe and F co-doped 0.35Li2MnO3·0.65LiNi 0.46 Co 0.08 Mn 0.46 O2 surface.

[0126] Example 4

[0127] The difference from Example 1 is that the doping elements are changed, with the anionic element being B provided by boric acid and the cation element being Fe provided by iron oxide, resulting in a modified lithium-rich manganese-based cathode material 0.35Li2MnO3·0.65LiNi. 0.46 Co 0.08 Mn 0.46 O2 and LATP adhere to Fe and B co-doped 0.35Li2MnO3·0.65LiNi 0.46 Co 0.08 Mn 0.46 O2 surface.

[0128] Example 5

[0129] The difference from Example 1 is that the doping elements are changed, with the anion element being P provided by ammonium dihydrogen phosphate and the cation element being Fe provided by iron oxide, resulting in a modified lithium-rich manganese-based cathode material 0.35Li₂MnO₃·0.65LiNi. 0.46 Co 0.08 Mn 0.46 O2 and LATP adhere to Fe and P co-doped 0.35Li2MnO3·0.65LiNi 0.46 Co 0.08 Mn0.46 O2 surface.

[0130] Example 6

[0131] The difference from Example 1 is that the doping elements are changed, with the anionic element being N provided by urea and the cationic element being Fe provided by iron oxide, resulting in a modified lithium-rich manganese-based cathode material 0.35Li₂MnO₃·0.65LiNi. 0.46 Co 0.08 Mn 0.46 O2 and LATP adhere to Fe and N co-doped 0.35Li2MnO3·0.65LiNi 0.46 Co 0.08 Mn 0.46 O2 surface.

[0132] Example 7

[0133] The difference from Example 1 is that the doping elements are changed, with the anion element being Cl provided by ammonium chloride and the cation element being Na provided by sodium carbonate, resulting in a modified lithium-rich manganese-based cathode material 0.35Li₂MnO₃·0.65LiNi. 0.46 Co 0.08 Mn 0.46 O2 and LATP adhere to 0.35Li2MnO3·0.65LiNi co-doped with Na and Cl. 0.46 Co 0.08 Mn 0.46 O2 surface.

[0134] Example 8

[0135] The difference from Example 1 is that the doping elements are changed, with the anion element being Cl provided by ammonium chloride and the cation element being Ti provided by titanium oxide, resulting in a modified lithium-rich manganese-based cathode material 0.35Li₂MnO₃·0.65LiNi. 0.46 Co 0.08 Mn 0.46 O2 and LATP adhere to the Ti and Cl co-doped 0.35Li2MnO3·0.65LiNi 0.46 Co 0.08 Mn 0.46 O2 surface.

[0136] Example 9

[0137] The difference from Example 1 is that the doping elements are changed, with the anion element being Cl provided by ammonium chloride and the cation element being Mg provided by magnesium oxide, resulting in a modified lithium-rich manganese-based cathode material 0.35Li2MnO3·0.65LiNi. 0.46 Co 0.08 Mn 0.46O2 and LATP adhere to Mg and Cl co-doped 0.35Li2MnO3·0.65LiNi 0.46 Co 0.08 Mn 0.46 O2 surface.

[0138] Example 10

[0139] The difference from Example 1 is that the doping elements are changed, with the anion element being Cl provided by ammonium chloride and the cation element being Nb provided by niobium oxide, resulting in a modified lithium-rich manganese-based cathode material 0.35Li₂MnO₃·0.65LiNi. 0.46 Co 0.08 Mn 0.46 O2 and LATP adhere to Nb and Cl co-doped 0.35Li2MnO3·0.65LiNi 0.46 Co 0.08 Mn 0.46 O2 surface.

[0140] Example 11

[0141] The difference from Example 1 is that the doping elements are changed, with the anion element being Cl provided by ammonium chloride and the cation element being Cr provided by chromium oxide, resulting in a modified lithium-rich manganese-based cathode material 0.35Li2MnO3·0.65LiNi. 0.46 Co 0.08 Mn 0.46 O2 and LATP adhere to Cr and Cl co-doped 0.35Li2MnO3·0.65LiNi 0.46 Co 0.08 Mn 0.46 O2 surface.

[0142] Example 12

[0143] The difference from Example 1 is that the doping elements are changed, with the anion element being Cl provided by ammonium chloride and the cation element being Ernium oxide, resulting in a modified lithium-rich manganese-based cathode material 0.35Li2MnO3·0.65LiNi. 0.46 Co 0.08 Mn 0.46 O2 and LATP adhere to Er and Cl co-doped 0.35Li2MnO3·0.65LiNi 0.46 Co 0.08 Mn 0.46 O2 surface.

[0144] Example 13

[0145] The difference from Example 1 is that the proportion of doping elements is changed. The mass ratio of iron to the theoretical lithium-rich manganese-based material is 2000 ppm, the mass ratio of chlorine to the theoretical lithium-rich manganese-based material is 600 ppm, and M1 / M2 = 1:0.3.

[0146] Example 14

[0147] The difference from Example 1 is that the proportion of doping elements is changed. The mass ratio of iron to the theoretical lithium-rich manganese-based material is 2000 ppm, the mass ratio of chlorine to the theoretical lithium-rich manganese-based material is 4000 ppm, and M1 / M2 = 1:2.

[0148] Example 15

[0149] The difference from Example 1 is that the proportion of doping elements is changed. The mass ratio of iron to the theoretical lithium-rich manganese-based material is 2000 ppm, the mass ratio of chlorine to the theoretical lithium-rich manganese-based material is 1000 ppm, and M1 / M2 = 1:0.5.

[0150] Example 16

[0151] The difference from Example 1 is that the proportion of doping elements is changed. The mass ratio of iron to the theoretical lithium-rich manganese-based material is 2000 ppm, the mass ratio of chlorine to the theoretical lithium-rich manganese-based material is 3000 ppm, and M1 / M2 = 1:1.5.

[0152] Example 17

[0153] The difference from Example 1 is that the amount of doping elements is changed. The mass ratio of iron to the theoretical lithium-rich manganese-based material is 1000 ppm, the mass ratio of chlorine to the theoretical lithium-rich manganese-based material is 1000 ppm, and M1 / M2 = 1:1.

[0154] Example 18

[0155] The difference from Example 1 is that the amount of doping elements is changed. The mass ratio of iron to the theoretical lithium-rich manganese-based material is 10,000 ppm, the mass ratio of chlorine to the theoretical lithium-rich manganese-based material is 10,000 ppm, and M1 / M2 = 1:1.

[0156] Example 19

[0157] The difference from Example 1 is that the amount of doping elements is changed. The mass ratio of iron to the theoretical lithium-rich manganese-based material is 20,000 ppm, the mass ratio of chlorine to the theoretical lithium-rich manganese-based material is 20,000 ppm, and M1 / M2 = 1:1.

[0158] Example 20

[0159] The difference from Example 1 is that the amount and ratio of doping elements are changed. The mass ratio of iron to the theoretical lithium-rich manganese-based material is 20,000 ppm, the mass ratio of chlorine to the theoretical lithium-rich manganese-based material is 40,000 ppm, and M1 / M2 = 1:2.

[0160] Example 21

[0161] The difference from Example 1 is that the amount of doping elements is changed. The mass ratio of iron to the theoretical lithium-rich manganese-based material is 25,000 ppm, the mass ratio of chlorine to the theoretical lithium-rich manganese-based material is 25,000 ppm, and M1 / M2 = 1:1.

[0162] Example 22

[0163] The difference from Example 1 is that the amount of doping elements is changed. The mass ratio of iron to the theoretical lithium-rich manganese-based material is 5000 ppm, the mass ratio of chlorine to the theoretical lithium-rich manganese-based material is 5000 ppm, and M1 / M2 = 1:1.

[0164] Example 23

[0165] The difference from Example 1 is that the amount of doping elements is changed. The mass ratio of iron to the theoretical lithium-rich manganese-based material is 25,000 ppm, the mass ratio of chlorine to the theoretical lithium-rich manganese-based material is 25,000 ppm, and M1 / M2 = 1:1.

[0166] Example 24

[0167] The difference from Example 1 is that the amount and ratio of doping elements are changed. The mass ratio of iron to the theoretical lithium-rich manganese-based material is 25,000 ppm, the mass ratio of chlorine to the theoretical lithium-rich manganese-based material is 1,000 ppm, and M1 / M2 = 1:0.04.

[0168] Example 25

[0169] The difference from Example 1 is that the amount and ratio of doping elements are changed. The mass ratio of iron to the theoretical lithium-rich manganese-based material is 25,000 ppm, the mass ratio of chlorine to the theoretical lithium-rich manganese-based material is 50,000 ppm, and M1 / M2 = 1:2.

[0170] Example 26

[0171] The difference from Example 1 is that the amount and ratio of doping elements are changed. The mass ratio of iron to the theoretical lithium-rich manganese-based material is 2000 ppm, the mass ratio of chlorine to the theoretical lithium-rich manganese-based material is 5000 ppm, and M1 / M2 = 1:2.5.

[0172] Example 27

[0173] The difference from Example 1 is that LATP is replaced with an equal weight of LAGP.

[0174] Example 28

[0175] The difference from Example 1 is that LATP is replaced with an equal weight of LLZO.

[0176] Example 29

[0177] The difference from Example 1 is that LATP is replaced with an equal weight of LLTO.

[0178] Example 30

[0179] The difference from Example 1 is that an equal weight of LiPO3 is used to replace LATP.

[0180] Example 31

[0181] The difference from Example 1 is that the mass ratio of LATP to the lithium-rich manganese-based cathode material co-doped with anions and cations is 2000 ppm.

[0182] Example 32

[0183] The difference from Example 1 is that the mass ratio of LATP to the lithium-rich manganese-based cathode material co-doped with anions and cations is 20,000 ppm.

[0184] Example 33

[0185] The difference from Example 1 is that the mass ratio of LATP to the lithium-rich manganese-based cathode material co-doped with anions and cations is 10000 ppm.

[0186] Example 34

[0187] The difference from Example 1 is that the mass ratio of LATP to the lithium-rich manganese-based cathode material co-doped with anions and cations is 1500 ppm.

[0188] Example 35

[0189] The difference from Example 1 is that the mass ratio of LATP to the lithium-rich manganese-based cathode material co-doped with anions and cations is 25,000 ppm.

[0190] Example 36

[0191] Ni precursor 0.3 Co 0.05 Mn 0.65(OH)₂, lithium carbonate, iron oxide, and ammonium chloride were mixed in a plow mixer. Lithium carbonate and the precursor were weighed with a Li / Me (representing transition metals Ni, Co, and Mn) molar ratio of 1.38. The mass ratio of iron to the theoretical lithium-rich manganese-based material was 2000 ppm, and the mass ratio of chlorine to the theoretical lithium-rich manganese-based material was also 2000 ppm. The mixture was then sintered in a kiln at 600℃ for 8 hours, followed by a further increase to 900℃ and a holding time of 12 hours. The sintering atmosphere was air. This yielded a co-doped lithium-rich manganese-based cathode material. The obtained lithium-rich manganese-based cathode material was then mixed with LATP and sintered at a mass ratio of 7000 ppm to the co-doped lithium-rich manganese-based cathode material. The sintering temperature was 650℃, and the sintering time was 5 hours, yielding a modified lithium-rich manganese-based cathode material 0.35Li₂MnO₃·0.65LiNi. 0.46 Co 0.08 Mn 0.46 O2, i.e., LATP coated in Fe and Cl co-doped 0.35Li2MnO3·0.65LiNi 0.46 Co 0.08 Mn 0.46 O2 surface.

[0192] Example 37

[0193] Ni precursor 0.3 Co 0.05 Mn 0.65 (OH)₂, lithium carbonate, iron oxide, and ammonium chloride were mixed in a plow mixer. Lithium carbonate and the precursor were weighed with a Li / Me (representing transition metals Ni, Co, and Mn) molar ratio of 1.38. The mass ratio of iron to the theoretical lithium-rich manganese-based material was 2000 ppm, and the mass ratio of chlorine to the theoretical lithium-rich manganese-based material was also 2000 ppm. The mixture was then sintered in a kiln at 600℃ for 8 hours, followed by a further increase to 800℃ and a holding time of 20 hours. The sintering atmosphere was air. This yielded a co-doped lithium-rich manganese-based cathode material. The obtained lithium-rich manganese-based cathode material was then mixed with LATP and sintered at a mass ratio of 7000 ppm to the co-doped lithium-rich manganese-based cathode material. The sintering temperature was 650℃, and the sintering time was 5 hours, yielding a modified lithium-rich manganese-based cathode material 0.35Li₂MnO₃·0.65LiNi. 0.46 Co 0.08 Mn 0.46 O2, i.e., LATP coated in Fe and Cl co-doped 0.35Li2MnO3·0.65LiNi 0.46 Co 0.08 Mn 0.46 O2 surface.

[0194] Example 38

[0195] Ni precursor 0.3 Co 0.05 Mn 0.65 (OH)₂, lithium carbonate, iron oxide, and ammonium chloride were mixed in a plow mixer. Lithium carbonate and the precursor were weighed with a Li / Me (representing transition metals Ni, Co, and Mn) molar ratio of 1.38. The mass ratio of iron to the theoretical lithium-rich manganese-based material was 2000 ppm, and the mass ratio of chlorine to the theoretical lithium-rich manganese-based material was also 2000 ppm. The mixture was then sintered in a kiln at 600℃ for 8 hours, followed by heating to 1000℃ and holding for 10 hours. The sintering atmosphere was air. This yielded a lithium-rich manganese-based cathode material co-doped with anions and cations. The obtained lithium-rich manganese-based cathode material was then mixed with LATP and sintered at a mass ratio of 7000 ppm to the co-doped lithium-rich manganese-based cathode material. The sintering temperature was 650℃, and the sintering time was 5 hours, yielding a modified lithium-rich manganese-based cathode material 0.35Li₂MnO₃·0.65LiNi. 0.46 Co 0.08 Mn 0.46 O2, i.e., LATP coated in Fe and Cl co-doped 0.35Li2MnO3·0.65LiNi 0.46 Co 0.08 Mn 0.46 O2 surface.

[0196] Example 39

[0197] Ni precursor 0.3 Co 0.05 Mn 0.65 (OH)₂, lithium carbonate, iron oxide, and ammonium chloride were mixed in a plow mixer. Lithium carbonate and the precursor were weighed with a Li / Me (representing transition metals Ni, Co, and Mn) molar ratio of 1.38. The mass ratio of iron to the theoretical lithium-rich manganese-based material was 2000 ppm, and the mass ratio of chlorine to the theoretical lithium-rich manganese-based material was also 2000 ppm. The mixture was then sintered in a kiln at 600℃ for 8 hours, followed by a further increase to 900℃ and a holding time of 12 hours. The sintering atmosphere was air. This yielded a co-doped lithium-rich manganese-based cathode material. The obtained lithium-rich manganese-based cathode material was then mixed with LATP and sintered at a mass ratio of 7000 ppm to the co-doped lithium-rich manganese-based cathode material. The sintering temperature was 500℃, and the sintering time was 8 hours, yielding a modified lithium-rich manganese-based cathode material: 0.35Li₂MnO₃·0.65LiNi. 0.46 Co 0.08 Mn 0.46O2, i.e., LATP coated in Fe and Cl co-doped 0.35Li2MnO3·0.65LiNi 0.46 Co 0.08 Mn 0.46 O2 surface.

[0198] Example 40

[0199] Ni precursor 0.3 Co 0.05 Mn 0.65 (OH)₂, lithium carbonate, iron oxide, and ammonium chloride were mixed in a plow mixer. Lithium carbonate and the precursor were weighed with a Li / Me (representing transition metals Ni, Co, and Mn) molar ratio of 1.38. The mass ratio of iron to the theoretical lithium-rich manganese-based material was 2000 ppm, and the mass ratio of chlorine to the theoretical lithium-rich manganese-based material was also 2000 ppm. The mixture was then sintered in a kiln at 600℃ for 8 hours, followed by a further increase to 900℃ and a holding time of 12 hours. The sintering atmosphere was air. This yielded a lithium-rich manganese-based cathode material co-doped with anions and cations. The obtained lithium-rich manganese-based cathode material was then mixed with LATP and sintered at a mass ratio of 7000 ppm to the co-doped lithium-rich manganese-based cathode material. The sintering temperature was 700℃, and the sintering time was 4 hours, yielding a modified lithium-rich manganese-based cathode material 0.35Li₂MnO₃·0.65LiNi. 0.46 Co 0.08 Mn 0.46 O2, i.e., LATP coated in Fe and Cl co-doped 0.35Li2MnO3·0.65LiNi 0.46 Co 0.08 Mn 0.46 O2 surface.

[0200] Comparative Example 1

[0201] Ni precursor 0.3 Co 0.05 Mn 0.65(OH)2, lithium carbonate, and ammonium chloride were mixed in a plow mixer. Lithium carbonate and the precursor were weighed with a Li / Me (representing transition metals Ni, Co, and Mn) molar ratio of 1.38, and the mass ratio of chlorine to the theoretical lithium-rich manganese-based material was 2000 ppm. The mixture was then sintered in a kiln at 400℃ for 4 hours, followed by a further increase to 900℃ and holding for 12 hours. The sintering atmosphere was air. Chloride-doped lithium-rich manganese-based cathode material was obtained. This chloride-doped cathode material was then mixed with LATP and sintered at a mass ratio of 7000 ppm. The sintering temperature was 650℃, and the sintering time was 5 hours, yielding the modified lithium-rich manganese-based cathode material 0.35Li2MnO3·0.65LiNi. 0.46 Co 0.08 Mn 0.46 O2, i.e., LATP coated with chloride ion-doped 0.35Li2MnO3·0.65LiNi 0.46 Co 0.08 Mn 0.46 O2 surface.

[0202] Comparative Example 2

[0203] Ni precursor 0.3 Co 0.05 Mn 0.65 (OH)2, lithium carbonate, and iron oxide were mixed in a plow mixer. Lithium carbonate and the precursor were weighed with a Li / Me (representing transition metals Ni, Co, and Mn) molar ratio of 1.38, and the mass ratio of iron to the theoretical lithium-rich manganese-based material was 2000 ppm. The mixture was then sintered in a kiln at 400℃ for 4 hours, followed by a further increase to 900℃ and holding for 12 hours. The sintering atmosphere was air. This yielded an iron-doped lithium-rich manganese-based cathode material. The obtained iron-doped lithium-rich manganese-based cathode material was then mixed with LATP and sintered at a mass ratio of 7000 ppm. The sintering temperature was 650℃, and the sintering time was 5 hours, yielding a modified lithium-rich manganese-based cathode material: 0.35Li2MnO3·0.65LiNi. 0.46 Co 0.08 Mn 0.46 O2, i.e., LATP coated with iron-doped 0.35Li2MnO3·0.65LiNi 0.46 Co 0.08 Mn 0.46 O2 surface.

[0204] Comparative Example 3

[0205] Ni precursor 0.3 Co 0.05 Mn0.65 (OH)2, lithium carbonate, iron oxide, and ammonium chloride are mixed in a plow mixer. Lithium carbonate and the precursor are weighed with a Li / Me (representing transition metals Ni, Co, and Mn) molar ratio of 1.38. The mass ratio of iron to the theoretical lithium-rich manganese-based material is 2000 ppm, and the mass ratio of chlorine to the theoretical lithium-rich manganese-based material is 2000 ppm. The mixture is placed in a kiln for sintering, held at 400℃ for 4 hours, and then heated to 900℃ for 12 hours. The sintering atmosphere is air. The sintering yields a lithium-rich manganese-based cathode material co-doped with anions and cations.

[0206] Comparative Example 4

[0207] Ni precursor 0.3 Co 0.05 Mn 0.65 (OH)2 and lithium carbonate were mixed in a plow mixer, with lithium carbonate and the precursor weighed out at a Li / Me (representing transition metals Ni, Co, and Mn) molar ratio of 1.38. The mixture was then placed in a kiln for sintering at 400℃ for 4 hours, followed by heating to 900℃ and holding for 12 hours. The sintering atmosphere was air, and the resulting material was lithium-rich manganese-based cathode material. The obtained lithium-rich manganese-based cathode material was then mixed with LATP (7000 ppm by mass) and sintered at 650℃ for 5 hours to obtain the modified lithium-rich manganese-based cathode material 0.35Li2MnO3·0.65LiNi. 0.46 Co 0.08 Mn 0.46 O2, i.e., LATP coated in 0.35Li2MnO3·0.65LiNi 0.46 Co 0.08 Mn 0.46 O2 surface.

[0208] Comparative Example 5

[0209] Ni precursor 0.3 Co 0.05 Mn 0.65 (OH)2 and lithium carbonate are mixed in a plow mixer. Lithium carbonate and precursor are weighed with a Li / Me (representing transition metals Ni, Co and Mn) molar ratio of 1.38. The mixture is placed in a kiln for sintering, held at 400℃ for 4 hours, and then heated to 900℃ for 12 hours. The sintering atmosphere is air. The sintering yields lithium-rich manganese-based cathode material.

[0210] Test method:

[0211] 1. Performance testing of positive electrode active materials

[0212] 1) Dv50, Dv10, and Dv90 particle size testing.

[0213] Particle size distribution can be conveniently determined using a laser particle size analyzer, such as the Mastersizer 2000E laser particle size analyzer from Malvern Instruments Ltd., UK, in accordance with GB / T 19077-2016 Laser Diffraction Method.

[0214] 2) Determination of specific surface area

[0215] Referring to GB / T 19587-2017, the nitrogen adsorption specific surface area was tested using the nitrogen adsorption specific surface area analysis method and calculated using the BET (Brunauer Emmett Teller) method. The nitrogen adsorption specific surface area analysis can be performed using the Tri-Star 3020 specific surface area and pore size analyzer from Micromeritics, USA.

[0216] 3) Molecular Structure of Core Materials: The molecular structure of core materials can be determined using known methods. For example, inductively coupled plasma atomic emission spectrometry (ICP-AES) can be used for testing.

[0217] 4) Thickness test of primary particles on the surface of the cathode material

[0218] The thickness of the primary particles on the surface of the cathode material can be measured using known methods. A high-resolution electron microscope can be used to calibrate the thickness of the primary particles, and then the measurement can be performed according to the length of the scale bar.

[0219] 5) Test methods for crystal parameters

[0220] XRD analysis was performed on the cathode material. The XRD scanning range was 2θ = 10°-80°, the scanning speed was ≤2° / min, and the step size was 0.2-0.02°. The obtained XRD patterns were refined in JADE software, and the peak area values ​​of the characteristic peaks of 003, 104 and 002 of the cathode material were calculated from the refined XRD patterns.

[0221] 6) Conductivity testing methods

[0222] The conductivity was measured using the well-known AC impedance method. The positive electrode material was pressed into a disc with a diameter of 12.5 mm and a thickness of 2-3 mm. Then, conductive silver paste was coated on both sides of the disc to serve as an electronic conductor and an ion insulator. The frequency range of the AC impedance was 1 MHz to 0.1 Hz, and the disturbance signal was 5 mV.

[0223] The measurement results are recorded in Table 1.

[0224]

[0225]

[0226]

[0227] 3) Cyclic performance test: Under a constant temperature environment of 25℃, the first charge and discharge were performed. Constant current and constant voltage charging was carried out at a charging current of 0.5C (i.e., the current value that completely discharges the theoretical capacity within 2 hours) until the upper limit voltage reaches 4.46V. After resting for 5 minutes, constant current discharge was carried out at a discharge current of 0.5C until the final voltage is 2.3V. The discharge capacity of the first cycle was recorded. Then, continuous charge and discharge cycles were performed.

[0228] The capacity retention rate of the nth cycle = (discharge capacity of the nth cycle / discharge capacity of the first cycle) × 100%.

[0229] The results are recorded in Table 2.

[0230] Table 2

[0231]

[0232]

[0233] Comparative analysis revealed that Fe and Cl, and Na and F significantly improved the first-efficiency and cycle performance of the material. However, when the amount and proportion of doping elements exceeded the acceptable range, the material performance decreased significantly. This is mainly because excessively low doping amounts and proportions fail to achieve the desired effect, while excessively high doping amounts and proportions prevent the doping elements from penetrating the material interior, causing them to remain on the surface and form impurity phases, thus affecting performance. Appropriate coatings and coating amounts for fast ion conductors can effectively improve the ion conductivity of the material. Too much or too little coating will lead to a decrease in the ion conductivity. Furthermore, different sintering regimes can cause differences in the crystallinity of the material, thus affecting its performance. Compared with uncoated and undoped samples, the material of this invention exhibits excellent first-efficiency, rate capability, and cycle performance.

[0234] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A modified lithium-rich manganese-based material, wherein the modified lithium-rich manganese-based material comprises: A lithium-rich manganese-based material co-doped with cations and anions, the chemical formula of the lithium-rich manganese-based material being xLi2MnO3•(1-x)LiNi y Co z Mn a O2, where 0 < x < 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1, y + z + a = 1; the doped cationic element M1 is Fe, the doped anionic element M2 is Cl, the doping amount of the doped cationic element M1 is 1000 - 2000 ppm, and the doping amount of the doped anionic element M2 is 1000 - 4000 ppm; A fast ion conductor material, wherein the fast ion conductor material is attached to the lithium-rich manganese-based material co-doped with anions and cations, the fast ion conductor material being LATP, and the weight content of the fast ion conductor material in the modified lithium-rich manganese-based material being 2000~10000 ppm. The thickness of the primary particles of the modified lithium-rich manganese-based material is 100~300nm.

2. The modified lithium-rich manganese-based material according to claim 1, wherein, The doping amount of M1 / M2 is 1:(0.3~2).

3. The modified lithium-rich manganese-based material according to claim 1, wherein, The doping amount of M1 / M2 is 1:(0.5~1.5).

4. The modified lithium-rich manganese-based material according to any one of claims 1 to 3, wherein, The electrical conductivity of the modified lithium-rich manganese-based material is 10~60 µS / cm.

5. The modified lithium-rich manganese-based material according to claim 4, wherein, The electrical conductivity of the modified lithium-rich manganese-based material is 30~60 µS / cm.

6. The modified lithium-rich manganese-based material according to any one of claims 1 to 3, wherein, The specific surface area of ​​the modified lithium-rich manganese-based material is <3.2 m². 2 / g.

7. The modified lithium-rich manganese-based material according to claim 6, wherein, The modified lithium-rich manganese-based material has a specific surface area of ​​0.3~2.2 m². 2 / g.

8. The modified lithium-rich manganese-based material according to any one of claims 1 to 3, wherein, The volumetric particle size distribution of the modified lithium-rich manganese-based material satisfies (Dv90-Dv10) / Dv50≥1.

1.

9. The modified lithium-rich manganese-based material according to claim 8, wherein, (Dv90-Dv10) / Dv50≥1.

2.

10. The modified lithium-rich manganese-based material according to any one of claims 1 to 3, wherein, The modified lithium-rich manganese-based material has a powder compaction density of ≥3.0 g / cc under 5 tons of pressure.

11. The modified lithium-rich manganese-based material according to any one of claims 1 to 3, wherein, In the X-ray diffraction pattern of the modified lithium-rich manganese-based material, the peak area ratio of I003 / I104 is 1.0~1.2; the peak area ratio of I020 / (I003+I104) is 0.005~0.

05.

12. The modified lithium-rich manganese-based material according to claim 11, wherein, The peak area ratio of I003 / I104 is 1.05~1.

15.

13. The modified lithium-rich manganese-based material according to claim 11, wherein, The peak area ratio of I020 / (I003+I104) is 0.008~0.

02.

14. The modified lithium-rich manganese-based material according to claim 11, wherein, The 003 and 104 characteristic peaks of the modified lithium-rich manganese-based material are shifted to the left relative to the -003 and 104 characteristic peaks of the lithium-rich manganese-based material.

15. A method for modifying lithium-rich manganese-based materials, wherein, The modification method includes: Step S1: Perform first sintering on the first mixture, where the first mixture includes a lithium-rich manganese-based precursor, a lithium salt, a substance containing cationic element M1, and a substance containing anionic element M2, to obtain a lithium-rich manganese-based material co-doped with cations and anions. The chemical formula of the lithium-rich manganese-based material is xLi2MnO3•(1-x)LiNi y Co z Mn a O2, where 0 < x < 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1, and y + z + a = 1; the cationic element M1 is Fe, the anionic element M2 is Cl, and the mass ratio of the cationic element M1 to the anionic element M2 is 1:(0.3 - 2). The mass ratio of M1 in the substance containing the cationic element M1 to the lithium-rich manganese-based material is 1000 - 2000 ppm, and the mass ratio of M2 in the substance containing the anionic element M2 to the lithium-rich manganese-based material is 1000 - 4000 ppm; S2: A second mixture comprising a fast ion conductor material and the anion-cation co-doped lithium-rich manganese-based material is subjected to a second sintering to obtain a modified lithium-rich manganese-based material. The modified lithium-rich manganese-based material comprises the anion-cation co-doped lithium-rich manganese-based material and the fast ion conductor material. The fast ion conductor material is LATP. The thickness of the primary particles of the modified lithium-rich manganese-based material is 100~300nm. The mass ratio of the fast ion conductor material to the anion-cation co-doped lithium-rich manganese-based material is 2000~10000ppm.

16. The modification method according to claim 15, wherein, The chemical formula of the lithium-rich manganese-based precursor is Ni b Co c Mn 1-b-c (OH)2, where 0.05≥c≥0, 0.4≥b>0.

17. The modification method according to claim 16, wherein, The lithium salt is one or more of lithium hydroxide, lithium carbonate, or lithium acetate.

18. The modification method according to claim 16, wherein, The molar ratio of the sum of transition metal elements in the lithium-rich manganese-based precursor to lithium in the lithium salt is 1:(1.1~1.8).

19. The modification method according to claim 18, wherein, The molar ratio of the sum of transition metal elements in the lithium-rich manganese-based precursor to lithium in the lithium salt is 1:(1.1~1.5).

20. The modification method according to any one of claims 15 to 19, wherein, The substance containing the cationic element M1 is an oxide or salt of M1.

21. The modification method according to any one of claims 15 to 19, wherein, The substance containing the anionic element M2 is an element, a salt, or an organic compound.

22. The modification method according to any one of claims 15 to 19, wherein, The first sintering process includes a first sintering process and a second sintering process, wherein the sintering temperature of the first sintering process is 400~600℃ and the holding time is 4~8h; the sintering temperature of the second sintering process is 800~1000℃ and the holding time is 10~20h.

23. The modification method according to any one of claims 15 to 19, wherein, The second sintering temperature is 500~700℃ and the holding time is 4~8h.

24. A secondary battery, comprising a positive electrode, a separator, and a negative electrode, wherein the positive electrode includes a positive electrode film layer, and the positive electrode film layer includes a positive electrode active material, wherein... The positive electrode active material includes the modified lithium-rich manganese-based material according to any one of claims 1 to 14 or the modified lithium-rich manganese-based material obtained by the modification method according to any one of claims 15 to 23.

25. An electrical device comprising a secondary battery, wherein, The secondary battery is selected from the secondary battery described in claim 24.

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