Composite lithium manganate positive electrode material, preparation method thereof, electrode sheet and battery

Abstract

This invention provides a composite lithium manganese oxide cathode material, its preparation method, electrode sheet, and battery, relating to the field of lithium battery technology. The composite lithium manganese oxide cathode material has a core-shell structure; the core is lithium manganese oxide, and the shell is a composite coating layer covering the surface of the lithium manganese oxide; the composite coating layer includes a first coating layer and a second coating layer; the first coating layer is CuCe. x Fe 2‑x O4-yLi; the second coating layer includes PVDF particles. This application provides a double-layer core-shell structured lithium manganese oxide material. Its CuCe... x Fe 2‑x The O4-yLi inner layer reduces impedance and stabilizes the lattice through spinel isomorphism and doping, and anchors the PVDF outer layer based on oxygen vacancies; combined with the surface lithium gradient effect, it significantly improves the structural stability and electrochemical performance of the material.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, and more specifically, to a composite lithium manganese oxide cathode material, its preparation method, electrode sheet, and battery. Background Technology

[0002] Lithium-ion batteries, as highly efficient electrochemical energy storage devices, have become an indispensable key technology in modern society due to their significant advantages such as high energy density, long cycle life, low self-discharge rate, and no memory effect. Their applications have expanded from initial portable consumer electronics products, such as smartphones and laptops, to strategic fields such as transportation electrification (including electric vehicles and electric bicycles), large-scale grid energy storage, and aerospace. A typical lithium-ion battery mainly consists of four parts: a positive electrode, a negative electrode, an electrolyte, and a separator. Among these, the positive electrode material is the core element determining the battery's electrochemical performance. Its structure, composition, and stability directly affect the battery's energy density, power density, cycle life, safety performance, and manufacturing cost. Therefore, the research and development of high-performance positive electrode materials is a continuous driving force for the advancement of lithium-ion battery technology.

[0003] Among numerous cathode material systems, spinel-structured lithium manganese oxide (LiMn2O4) has attracted widespread attention due to its unique advantages. This material possesses a three-dimensional lithium-ion diffusion channel, abundant resources, environmental friendliness, relatively low production costs, and boasts a high operating voltage platform, excellent safety performance, and high volumetric energy density. Thanks to these characteristics, lithium manganese oxide cathode materials have achieved large-scale commercial applications in fields with high requirements for cost and safety but relatively less stringent requirements for energy density and cycle life, playing a particularly important role in the power battery systems of electric bicycles and other low-speed electric vehicles.

[0004] However, despite the aforementioned advantages, lithium manganese oxide's inherent defects significantly limit its application in more advanced and demanding fields. Currently, lithium manganese oxide cathode materials face two major challenges in practical applications: firstly, poor cycle performance, resulting in rapid capacity decay during use; and secondly, insufficient high-temperature stability, with performance deteriorating drastically at higher temperatures (e.g., above 55°C). These shortcomings make it difficult for lithium manganese oxide to meet the requirements of long-range, long-life automotive-grade power batteries, leading to its low market share in the rapidly developing field of lithium-ion batteries for new energy vehicles. The root cause of these problems lies in the low intrinsic conductivity of lithium manganese oxide materials. This characteristic leads to severe electrochemical polarization under conditions such as high-rate charge / discharge, low-temperature environments, and the final stage of discharge.

[0005] A series of chain reactions triggered by polarization is the key mechanism causing the performance degradation of lithium manganese oxide. Under polarized conditions, a large number of unstable trivalent manganese ions (Mn) are generated on the surface of lithium manganese oxide.3+ These Mn3+ ions readily undergo disproportionation reactions, with some converting into stable tetravalent manganese ions and the rest into divalent manganese ions (Mn3+) soluble in the electrolyte. 2+ These dissolved Mn 2+ Ions migrate through the separator to the negative electrode of the battery and deposit on its surface, blocking the diffusion channels of lithium ions and damaging the solid electrolyte interphase (SEI) film. This leads to irreversible capacity loss and an increase in internal resistance, ultimately causing a rapid end to the battery's cycle life. Therefore, the two interconnected defects of poor cycle performance and insufficient high-temperature stability are essentially closely related to the dissolution and migration of manganese, representing a core technological bottleneck hindering the further development of lithium manganese oxide materials.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] The purpose of this invention is to provide a composite lithium manganese oxide cathode material and its preparation method. The composite lithium manganese oxide cathode material significantly improves the performance of lithium manganese oxide through a core-shell structure: the isomorphic spinel inner layer reduces interfacial impedance and promotes ion transport; Li doping stabilizes the lattice, and Ce introduces oxygen vacancies to improve conductivity and tightly anchor the outer PVDF layer through Lewis acid-base interaction; the lithium concentration gradient constructed by the outer fluorine element further optimizes the electrochemical performance.

[0008] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0009] In a first aspect, the present invention provides a composite lithium manganese oxide cathode material, wherein the composite lithium manganese oxide cathode material has a core-shell structure; its core is lithium manganese oxide, and its shell is a composite coating layer covering the surface of lithium manganese oxide;

[0010] The composite coating layer includes a first coating layer and a second coating layer that are sequentially coated from the inside out;

[0011] The chemical formula of the first coating layer is CuCe x Fe 2-x O4-yLi; where 0≤x≤1, y represents the mass fraction of the lithium doping source, and y is 0%~5%;

[0012] The second coating layer comprises PVDF particles.

[0013] In an optional embodiment, the first coating layer accounts for 1 wt% to 5 wt% of the lithium manganese oxide by mass; and / or,

[0014] The second coating layer comprises 1 wt% to 5 wt% of the lithium manganese oxide by mass; and / or,

[0015] In the first coating layer, CuCe x Fe 2-x The particle size of O4-yLi particles is 0.2 μm to 1 μm; and / or,

[0016] In the second coating layer, the PVDF particles have a particle size of 0.1~1μm.

[0017] Secondly, the present invention also provides a method for preparing the composite lithium manganese oxide cathode material as described in the foregoing embodiments, comprising:

[0018] S1, Preparation of CuCe x Fe 2-x O4-yLi particles;

[0019] S2, CuCe x Fe 2-x O4-yLi particles are coated on the surface of lithium manganese oxide to form the first coating layer;

[0020] S3. A second coating layer is formed on the surface of the first coating layer to form the composite lithium manganese oxide cathode material.

[0021] In an optional implementation, the CuCe described in step S1 x Fe 2-x The preparation methods of O4-yLi particles include:

[0022] The metal nitrates of Cu, Ce and Fe were weighed in a metal element molar ratio of 1:x:(2-x) and placed in a container. Li nitrate with a mass fraction of y was added and water was added and stirred until dissolved to obtain a mixed solution, wherein y is 0%~5%.

[0023] Ammonia water was added to the mixture and stirred continuously to obtain a precipitate with pH=7~13;

[0024] The precipitate was filtered under reduced pressure and washed with ultrapure water until the pH reached 6-8. The precipitate was then separated by vacuum filtration and dried to obtain a solid powder.

[0025] The solid powder was subjected to crystallization treatment to obtain the target material with good crystallinity, namely CuCe. x Fe 2-x O4-y%Li.

[0026] In an optional embodiment, the stirring time is 1 hour to 2 hours; and / or,

[0027] The crystallization treatment temperature is 300℃~600℃;

[0028] The heating rate of the crystallization treatment is 3℃ / min to 10℃ / min;

[0029] The holding time for the crystallization treatment is 2h~5h;

[0030] The cooling rate of the crystallization process is natural cooling within the furnace.

[0031] In an optional implementation, the method for forming the first coating layer includes:

[0032] CuCe x Fe 2-x O4-y%Li was dispersed in anhydrous ethanol, and lithium manganate was added and ultrasonically stirred to obtain a mixed dispersion.

[0033] The solid material after drying the mixed dispersion is heated to 450°C to 550°C under a protective atmosphere to form the first coating layer.

[0034] In an optional implementation, step S3 includes:

[0035] The composite lithium manganese oxide cathode material is obtained by fusing lithium manganese oxide particles coated with the first coating layer and PVDF particles using a high-speed mechanical fusion method, followed by high-temperature sintering and cooling.

[0036] Thirdly, the present invention also provides an electrode, comprising the composite lithium manganese oxide cathode material as described above, or comprising the composite lithium manganese oxide cathode material obtained by the preparation method of the composite lithium manganese oxide cathode material as described above.

[0037] Fourthly, the present invention also provides a battery comprising the electrodes as described above.

[0038] Fifthly, the present invention also provides an electrical device, including the battery as described above.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] This composite lithium manganese oxide cathode material significantly improves the structural stability of lithium manganese oxide by constructing a special composite coating layer, thereby improving the battery's electrical cycle performance and safety performance.

[0041] First, the lithium manganese oxide core and the first coating layer CuCe x Fe 2-x Both O4-yLi have spinel structures, and their high structural compatibility effectively reduces interfacial impedance; at the same time, the inherent three-dimensional Li... + The transport channels achieve a good match at the core-shell interface, which significantly improves the transport efficiency of lithium ions.

[0042] Secondly, after the first coating layer is doped with lithium, the smaller Li... +It enters the spinel lattice, occupies the tetrahedral interstitial space, or replaces part of the Cu. 2+ This forms a Li-O-Fe / Ce ion channel, reducing the Li + The migration energy barrier is high; moreover, the formed Li-O chemical bond has a high bond energy, which can suppress the Fe during charging and discharging. 3+ / Fe 2+ Ce 3+ / Ce 4+ The lattice fluctuations caused by valence changes enhance lattice stability. Simultaneously, the introduction of Ce creates lattice defects such as oxygen vacancies, which in turn promote the growth of Li. + The diffusion within the coating layer enhances electronic conductivity. On the other hand, the oxygen vacancies, which are typical Lewis acids, undergo Lewis acid-base reactions with the fluorine elements in the second coating layer PVDF that provide electrons, significantly strengthening the bonding force between the first and second coating layers.

[0043] In addition, the fluorine element in the outermost PVDF layer has strong electronegativity and can adsorb free lithium ions to form LiF, so that the overall composite lithium manganese oxide cathode material forms a gradient distribution with high lithium concentration in the inner layer and low lithium concentration in the outer layer. This gradient distribution and the formation of the LiF protective layer can significantly improve the lithium replenishment effect and overall electrochemical performance of the material. Attached Figure Description

[0044] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0045] Figure 1 This is a schematic diagram of the structure of the composite lithium manganese oxide cathode material provided in the embodiments of this application;

[0046] Figure 2 This is a schematic flowchart of the preparation method of the composite lithium manganese oxide cathode material provided in the embodiments of this application;

[0047] Figure 3 This is a SEM image of the cathode material in Example 1 of this application;

[0048] Figure 4 The images show the XRD patterns of the cathode materials used in the embodiments and comparative examples of this application.

[0049] Figure label:

[0050] 100, composite lithium manganese oxide cathode material; 1, lithium manganese oxide; 2, composite coating layer; 21, first coating layer; 22, second coating layer. Detailed Implementation

[0051] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0052] refer to Figure 1 In this embodiment of the application, a composite lithium manganese oxide cathode material is provided. The composite lithium manganese oxide cathode material has a core-shell structure; its core is lithium manganese oxide, and its shell is a composite coating layer covering the surface of lithium manganese oxide; the composite coating layer includes a first coating layer and a second coating layer sequentially coated from the inside to the outside; the chemical formula of the first coating layer is CuCe. x Fe 2- x O4-yLi; where 0≤x≤1, y represents the mass fraction of the lithium doping source, and y is 0%~5%; the second coating layer includes PVDF particles.

[0053] The y above represents the mass fraction, which can be a percentage of a natural number between 0 and 5, such as 1%, 2%, 3%, 4%, 5%, etc. The x above can be, for example, 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, etc.

[0054] The aforementioned composite lithium manganese oxide cathode material is a material used in lithium-ion batteries. Its main component is lithium manganese oxide, but it has been modified through a "composite" approach (i.e., combined with other substances) to improve its performance.

[0055] The composite structure aims to improve the inherent defects of traditional lithium manganese oxide materials, such as insufficient cycle performance and high-temperature stability.

[0056] The structure consists of a central "core" and an outer "shell," a morphological description that indicates each particle of the material is not uniform, but rather, like an egg, consists of a kernel (yolk) and a shell (egg white and shell).

[0057] The aforementioned core-shell structure may include:

[0058] (1) Active material core (internal core): This is the main part of the positive electrode material, which is responsible for storing and releasing lithium ions. It is the source and destination of lithium ions during the charging and discharging process of the battery.

[0059] (2) Composite coating layer (outer layer): This is a material that covers the outer surface of the active material. Its function is to improve the performance of the active material, such as improving stability, safety and electrochemical performance.

[0060] The basic principle is surface modification. By constructing a functional shell on the surface of the core material, its surface properties can be optimized and its interaction with the electrolyte inside the battery can be improved without changing the main function of the core material.

[0061] The core-shell structure can physically isolate the core lithium manganese oxide from the electrolyte, effectively suppressing side reactions and thus improving the structural stability of the material, thereby enhancing the cycle performance and safety performance of the battery.

[0062] The core component mentioned above is lithium manganese oxide. It forms the main body and functional core of the entire composite material particles, serving as the active material for storing and releasing lithium ions. Lithium manganese oxide was chosen as the core because it possesses advantages such as abundant resources, low cost, high voltage, and good safety, providing a solid performance foundation for the entire composite material.

[0063] The outer shell is a composite covering layer. Its function and location are defined as "covering the outer surface of the core". The word "composite" indicates that the outer shell itself is not composed of a single material, but rather a multi-layered or hybrid structure made up of multiple components.

[0064] By using a composite coating layer, multiple functions can be integrated into a single shell, which can optimize performance more comprehensively than a shell made of a single material.

[0065] The aforementioned composite coating layer has a two-layer structure, consisting of a first coating layer and a second coating layer from the inside out. This further clarifies the specific structure of the composite coating layer; it is not a mixed layer, but rather two separate layers with a clear sequential order.

[0066] This is a principle of functional gradient design. The first coating layer, which directly contacts the core, can focus on solving interfacial problems with the core material (such as ion / electron transport), while the outermost second coating layer can focus on solving interfacial problems with the electrolyte (such as chemical stability).

[0067] This dual-layer design allows for a more refined division of functions than a single-layer design. For example, the first coating layer can improve conductivity, while the second coating layer can improve stability. The combination of the two layers synergistically enhances overall performance.

[0068] The chemical formula of the first coating layer is CuCe. x Fe 2-x O4-y%Li is the basic chemical framework of the coating layer, which is a complex metal oxide containing copper (Cu), cerium (Ce), iron (Fe) and oxygen (O).

[0069] Where x represents the proportion of cerium (Ce) replacing iron (Fe), 0≤x≤1, meaning that this coating layer can be cerium-free (CuFe2O4 when x=0) or contain up to an equimolar amount of cerium as copper (CuCeFeO4 when x=1).

[0070] The y%Li section above indicates that the aforementioned composite metal oxide has been doped with lithium (Li). Here, y is defined as the "mass fraction of the doped lithium source," and its value can be 0, 1, 2, 3, 4, or 5. This means that the mass of the doped lithium source can range from 0% (i.e., undoped) to 5% of the total mass.

[0071] For example, if x=0.1 and y=2, then the material of the first cladding layer is CuCe. 0.1 Fe 1.9 The O4 is a composite oxide, and it is doped with 2% by mass of lithium source.

[0072] This layer, closely adhering to the lithium manganese oxide core, acts as a composite oxide and provides a physical barrier. By introducing doping with various metal elements (copper, cerium, iron) and lithium, the aim is to optimize the ionic and electronic conductivity of this layer, compensate for the low conductivity of lithium manganese oxide, and improve the stability of the interface structure.

[0073] The second coating layer described above consists of PVDF particles. PVDF (polyvinylidene fluoride) is a common polymer known for its excellent chemical stability and electrochemical inertness. Here, it exists in particulate form as the outermost layer. PVDF is rich in fluorine, which has strong electronegativity, and is chemically stable, making it resistant to corrosion by electrolytes.

[0074] As the outermost layer, PVDF provides a chemically stable protective layer, further preventing the core material from being corroded by the electrolyte. Simultaneously, the fluorine on its surface, due to its high electronegativity, can interact with lithium ions in the electrolyte, positively impacting the electrochemical environment of the material surface and contributing to improved overall performance.

[0075] In some embodiments, the first coating layer comprises 1 wt% to 5 wt% of the lithium manganese oxide by mass. For example, it can be 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, etc. In the final product, every 100 parts by mass of lithium manganese oxide core is coated with 1 to 5 parts by mass of the first coating layer material.

[0076] In some embodiments, the second coating layer accounts for 1 wt% to 5 wt% of the lithium manganese oxide by mass. For example, it can be 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, etc. That is, for every 100 parts by mass of lithium manganese oxide core, there are 1 to 5 parts by mass of PVDF material.

[0077] Setting a minimum content ensures a continuous and effective coating layer. If the mass fraction is too low (<1 wt%), it may not completely cover the lithium manganese oxide core surface, resulting in "exposed" areas and failing to achieve the described "core-shell structure" and its protective function. Setting a maximum content limits the coating layer thickness. If the mass fraction is too high (>5 wt%), the coating layer may be too thick, increasing the diffusion path and impedance of lithium ions during insertion / extraction, thus reducing the material's electrochemical activity.

[0078] In some embodiments, CuCe is present in the first coating layer. x Fe 2-x The particle size of O4-yLi particles ranges from 0.2 μm to 1 μm. For example, they can be 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.7 μm, 0.9 μm, 1 μm, etc.

[0079] In some embodiments, the particle size of the PVDF particles in the second coating layer is 0.1~1μm. For example, it can be 0.1μm, 0.2μm, 0.3μm, 0.4μm, 0.5μm, 0.7μm, 0.9μm, 1μm, etc.

[0080] Particles of this size can adhere well to the surface of lithium manganese oxide cores, which are typically in the micrometer range, forming a dense "shell" through physical stacking or fusion. If the particles are too large, it may be difficult to form a uniform and dense thin layer; if the particles are too small, they may easily agglomerate and be difficult to disperse evenly.

[0081] By controlling the mass fraction of the first and second coating layers to be 1wt%~5wt%, the integrity of the core-shell structure is ensured. This effectively isolates the electrolyte (protecting the core) without significantly hindering ion transport due to excessive coating thickness. Specific particle size ranges (0.1μm~1μm and 0.2μm~1μm) help form a uniformly distributed coating layer, avoiding localized accumulation or missing coatings, thus ensuring consistent material properties.

[0082] refer to Figure 2 This embodiment also provides a method for preparing a composite lithium manganese oxide cathode material, including:

[0083] S1, Preparation of CuCe x Fe 2-xO4-yLi particles.

[0084] This step is the raw material preparation stage. Its core purpose is to synthesize special functional material particles used to form the first coating layer.

[0085] According to the chemical formula CuCe x Fe 2-x O4-yLi, this step involves chemically reacting and physically treating source compounds of copper (Cu), cerium (Ce), and iron (Fe) with a lithium (Li) source.

[0086] CuCe x Fe 2-x O4-yLi constructed a spinel-structured composite metal oxide framework. Here, 0 ≤ x ≤ 1 represents the molar ratio of cerium replacing iron.

[0087] y represents the mass fraction of the lithium doping source (0%~5%), indicating that lithium was introduced into the oxide framework mentioned above.

[0088] This step yields solid powder particles with a specific chemical composition and crystal structure (usually spinel structure), which is the packaging material of the first coating layer.

[0089] By pre-synthesizing the first coating layer material, the proportion and crystal structure of doping elements (Li, Ce) can be precisely controlled, ensuring the uniformity of material properties during subsequent coating.

[0090] Furthermore, the CuCe mentioned in step S1 x Fe 2-x The preparation methods of O4-yLi particles include:

[0091] S11, weigh the metal nitrates of Cu, Ce and Fe in a metal element molar ratio of 1:x:(2-x) and place them in a container. Add Li nitrate with a mass fraction of y and add water and stir until dissolved to obtain a mixed solution, where y is 0%~5%.

[0092] In this step, copper (Cu), cerium (Ce), and iron (Fe) nitrates are weighed in a molar ratio of 1:x:(2-x) and placed in a container. Li nitrates with a mass fraction of y are added, weighed in the same molar ratio, and placed in the container. Lithium (Li) nitrates with a mass fraction of y are added; water is added and stirred until dissolved to obtain a mixture.

[0093] This is the preparation process of the precursor solution. Based on the chemical formula CuCe... x Fe 2-xO4-yLi was used to precisely calculate and weigh each metal salt. Here, 1 represents the molar amount of Cu, x represents the molar amount of Ce, and (2-x) represents the molar amount of Fe. This ensures that the atomic ratio of the metal cations meets the stoichiometric requirements of the spinel structure.

[0094] y is defined as mass fraction (0%~5%), which refers to the mass ratio of the additional lithium source introduced relative to the matrix material (or total feed), and is used for subsequent lithium doping.

[0095] Using water as a solvent, solid nitrates are converted into ionic states, resulting in a homogeneous and transparent mixed aqueous solution in which Cu, Ce, Fe, and Li ions are dispersed at the molecular / ionic level in the liquid phase.

[0096] Liquid-phase mixing ensures the uniformity of element mixing and avoids local component segregation that may occur in solid-phase mixing, laying the foundation for the synthesis of pure-phase materials. Implementation method: A magnetic stirrer or ultrasonic dispersion device is used to assist dissolution; deionized water or ultrapure water is typically used as the solvent to reduce impurities.

[0097] S12, add ammonia water to the mixture and stir continuously to obtain a precipitate with pH=7~13. For example, it can be 7, 8, 9, 10, 11, 12, or 13.

[0098] This step is crucial for converting metal ions in the liquid phase into a solid-phase precursor. Specifically, it may include the following processes:

[0099] (1) Addition of precipitant: Ammonia water (NH3·H2O) is added to the mixture as a precipitant and complexing agent.

[0100] (2) pH control: Adjust the pH of the system to an alkaline environment (7~13). Within this pH range, metal ions such as Cu, Ce, and Fe will combine with hydroxide ions to form hydroxide precipitates (such as Cu(OH)2, Fe(OH)3, etc.).

[0101] This step yields a suspension (precipitate) containing fine solid particles. Ammonia water can control the precipitation rate and particle morphology, contributing to the formation of precursors with fine and uniform particle size. Co-precipitation allows multiple metal ions to precipitate almost simultaneously, maintaining the stoichiometric ratio of the raw materials.

[0102] Specifically, ammonia can be added dropwise while using a pH meter to monitor the solution's acidity and alkalinity in real time until the set value (e.g., pH=9) is reached.

[0103] S13, the precipitate is filtered under reduced pressure and washed with ultrapure water until pH=6~8, then separated by vacuum filtration and dried to obtain solid powder.

[0104] This step is a post-treatment step to remove impurity ions and solvents.

[0105] The precipitate was separated from the mother liquor and repeatedly washed with water. The purpose was to remove reaction byproducts (such as nitrate ions and NO3-). - Ammonium ions NO4 + The solution contains residual ammonia. Wash until the effluent pH is neutral (6-8) to ensure no residual acid or alkali corrodes subsequent equipment or affects crystal growth. Then remove physically adsorbed moisture to obtain a pure, dry amorphous or low-crystallinity solid powder (precursor powder).

[0106] High-purity precursors prevent impurities from forming heterogeneous phases during high-temperature sintering, ensuring the electrochemical performance of the final material. This is achieved by using a vacuum filter for solid-liquid separation; drying is typically carried out in a forced-air drying oven (e.g., drying at 70°C).

[0107] S14, the solid powder is subjected to crystallization treatment to obtain the target material with good crystallinity, namely CuCe. x Fe 2-x O4-y%Li.

[0108] This step is the high-temperature solid-state reaction stage, also known as calcination.

[0109] This step requires the provision of heat energy to decompose the precursor powder (such as through dehydration and oxidation of hydroxides) and rearrange atoms to form an ordered crystal structure, thereby obtaining a final particulate product with a spinel structure, high crystallinity, and stable chemical composition.

[0110] Crystallization treatment imparts a stable lattice structure to the material, which is crucial for its structural stability and ion transport performance when used as a battery coating layer. This step determines the final material phase.

[0111] Place the dried powder in a muffle furnace or tube furnace and keep it at a specific temperature (such as 300℃~600℃ as mentioned in the instructions) for a certain period of time (such as 2~5 hours), while controlling the heating rate.

[0112] S2, CuCe x Fe 2-x O4-yLi particles coat the surface of lithium manganese oxide to form the first coating layer.

[0113] This step is the inner coating (intermediate construction) stage. The process involves uniformly attaching and fixing the functional particles prepared in step S1 onto the surface of the core material (lithium manganese oxide). This typically involves physical mixing and heat treatment to establish a physical or chemical bond between the core and the first layer, resulting in a composite intermediate—lithium manganese oxide particles whose surface is only coated with the first layer material. At this point, the lithium manganese oxide core is isolated from the external environment by the first coating layer.

[0114] This step establishes the interface between the core and the shell. Since the first coating layer and lithium manganese oxide both have a spinel structure, this step reduces the interfacial impedance and enhances conductivity by utilizing the oxygen vacancies introduced by Ce.

[0115] S3. A second coating layer is formed on the surface of the first coating layer to form the composite lithium manganese oxide cathode material.

[0116] This step is the outer coating (final forming) stage. The process involves covering the surface of the intermediate obtained in step S2 with another layer of PVDF (polyvinylidene fluoride) particles. This is to add an organic / polymer protective layer outside the inorganic coating layer, thereby obtaining the final composite lithium manganese oxide cathode material with a complete "core-inner shell-outer shell" double-layer structure.

[0117] Given that PVDF is a polymer material, it is usually fused together with a low-temperature sintering method to avoid damaging the inner layer structure.

[0118] (1) Mechanical fusion: The lithium manganese oxide coated with the first layer is mixed with PVDF particles and processed by a high-speed mechanical fusion machine, using mechanical force to "nail" the PVDF particles to the surface of the first coating layer.

[0119] (2) Sintering to form a film: The PVDF particles are softened or melted by sintering at high temperature (e.g., 550℃) for a short time, thereby firmly bonding them to the first coating layer.

[0120] High-speed mechanical fusion is an industrial mixing technique that involves using a high-speed rotating mechanical device to mix different materials. This method is used to prepare composite materials to ensure uniform distribution and good interfacial bonding among the components. Through high-speed mechanical fusion, this method can effectively and uniformly mix the first coating layer of lithium manganese oxide, PVDF particles, and fluorinated graphene, ensuring good contact and interfacial bonding between the materials.

[0121] This step utilizes the fluorine element in PVDF to react with the oxygen vacancies (Lewis acids) in the first coating layer, enhancing the interlayer bonding force. The introduction of the outer PVDF layer creates a lithium concentration gradient with a higher concentration inside and a lower concentration outside (through the formation of LiF) and provides a protective layer to isolate the electrolyte, ultimately improving the cycling stability and safety of the material.

[0122] In some implementations, the stirring time is 1 to 2 hours. For example, it can be 1 hour, 1.2 hours, 1.5 hours, 1.7 hours, 1.9 hours, 2 hours, etc.

[0123] The above describes the duration of mechanical or magnetic stirring after the step of "adding ammonia to the mixture". After the precipitant (ammonia) is added, the reaction is not stopped or filtered immediately, but the reaction system is allowed to continue to be dynamically mixed for 1 to 2 hours under stirring.

[0124] Allowing sufficient time for the metal ions and precipitant to contact and react ensures complete precipitation and improves yield. This period acts as a "aging" process, helping the precipitate particles to have more regular morphology and more uniform composition distribution, preventing agglomeration or impurity encapsulation caused by excessively high local concentrations.

[0125] Specifically, a constant speed mixer can be used to set a timer and continue mixing until the set time (e.g., 1.5 hours) is reached.

[0126] In some embodiments, the crystallization treatment temperature is 300°C to 600°C. For example, it can be 300°C, 400°C, 500°C, 600°C, etc.

[0127] This refers to the target temperature range for heating the dried precursor solid powder at high temperatures.

[0128] The powder can be placed in a heating device to reach and maintain a high temperature environment between 300°C and 600°C.

[0129] This temperature range is crucial for the formation of the target spinel crystal structure (CuCe). x Fe 2-x The required energy range for O4-yLi. Too low a temperature may result in incomplete crystallization or residual amorphous phase; too high a temperature may lead to excessive grain growth or wasted energy. Residue removal: High temperatures help to completely decompose volatile components such as nitrate and hydroxide ions remaining in the precursor.

[0130] Specifically, heating can be performed by setting a target temperature (e.g., 500°C) using a muffle furnace or tubular resistance furnace.

[0131] In some embodiments, the heating rate of the crystallization treatment is 3°C / min to 10°C / min. For example, it can be 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, etc.

[0132] This refers to the rate at which the heating equipment rises from room temperature (or initial temperature) to the target temperature (300℃~600℃). The heating power of the furnace can be controlled to ensure that the temperature rises steadily at a rate of 3℃ to 10℃ per minute.

[0133] Controlling the heating rate can prevent cracks or pores from forming inside the particles due to the rapid expulsion of moisture or volatiles. A moderate heating rate ensures that the powder is heated evenly, avoiding structural stress caused by thermal shock.

[0134] For example, a programmable temperature controller can be used to set the temperature rise rate.

[0135] In some embodiments, the holding time for the crystallization treatment is 2 hours to 5 hours. For example, it can be 2 hours, 3 hours, 4 hours, 5 hours, etc.

[0136] This refers to the duration for which the equipment maintains a constant temperature after reaching the set target temperature (300℃~600℃), allowing for prolonged "hot immersion" of powder under constant temperature conditions.

[0137] By controlling the holding time, sufficient time can be provided for atoms to diffuse and rearrange, eliminating lattice defects and improving crystallinity; ensuring that all powder particles react fully to form a uniform stoichiometric compound.

[0138] For example, the dwell time can be set through the heating program, such as setting it to keep warm for 3 hours.

[0139] In some embodiments, the cooling rate of the crystallization treatment is natural cooling with the furnace.

[0140] This refers to the method of cooling the material from high temperature back to room temperature after the insulation is completed.

[0141] Stop supplying power to the heating elements and do not take forced air cooling or water cooling measures, allowing the furnace body and samples to gradually reduce the temperature through natural heat dissipation.

[0142] Through the above controls, the slow cooling process helps to gradually release the thermal stress inside the crystal, preventing lattice distortion or microcracks caused by rapid cooling, thereby maintaining the integrity and stability of the particle structure. After the program is completed, turn off the power directly, keep the furnace door closed, and wait for the temperature to drop to a safe range (such as room temperature) before removing the sample.

[0143] In some embodiments, the method for forming the first coating layer includes:

[0144] (1) CuCe x Fe 2-x O4-y%Li was dispersed in anhydrous ethanol, and lithium manganese oxide was added and ultrasonically stirred to obtain a mixed dispersion.

[0145] This step involves uniformly mixing the core material and the coating material in a liquid medium.

[0146] Anhydrous ethanol was chosen as the solvent / dispersant. Ethanol has low surface tension and good volatility, and its "anhydrous" property avoids the side reactions that water may cause to lithium salts or lithium manganese oxide (such as lithium source dissolution and loss or lithium manganese oxide proton exchange).

[0147] In terms of the feeding sequence, first add the first coating layer material (CuCe) x Fe 2-x O4-y%Li) is dispersed in ethanol, and then lithium manganese oxide, the core material, is added. Then, "ultrasonic stirring" is used. Utilizing the cavitation effect generated by ultrasound in the liquid, local high temperature and pressure and microjets are generated, thereby obtaining a uniform suspension (mixed dispersion), in which tiny coated particles are uniformly attached or dispersed around larger lithium manganese oxide particles.

[0148] Ultrasonic waves can effectively break up the agglomeration of nano / submicron particles, resulting in more uniform mixing than simple mechanical stirring, ensuring that the coating material fully covers the core surface. Ethanol can effectively wet the powder surface, promoting contact between the two materials.

[0149] Specifically, the powder can be added to a beaker containing anhydrous ethanol, and the beaker can be placed in an ultrasonic cleaner or processed using the probe of an ultrasonic cell disruptor, while mechanical stirring can be used as an auxiliary method.

[0150] (2) The solid material after drying the mixed dispersion is heated to 450°C to 550°C (for example, 450°C, 460°C, 480°C, 500°C, 520°C, 530°C, 550°C, etc.) under a protective atmosphere to form the first coating layer.

[0151] This involves removing the solvent and using heat to firmly bond the coating to the core.

[0152] The solvent (anhydrous ethanol) is physically removed, transforming the liquid mixture into a solid powder. An inert gas (such as nitrogen or argon) is introduced during heating. This is to prevent unintended oxidation reactions of lithium manganese oxide or the metal elements (such as Fe, Cu) in the coating layer with oxygen in the air at high temperatures, or to prevent carbonization. The mixture is then heated to 450℃–550℃. This temperature range is considered medium-temperature sintering. Result: Ethanol completely evaporates, and CuCe... x Fe 2-x O4-y%Li particles are sintered onto the surface of lithium manganese oxide through thermal diffusion, forming a structurally stable and tightly bonded first coating layer.

[0153] The treatment method in this step has strong interfacial bonding. The temperature of 450℃ to 550℃ is sufficient to cause interatomic diffusion, so that the coating layer "grows" on the core, rather than simple physical adsorption, thereby reducing interfacial impedance. Compared with higher temperatures (such as >700℃), this temperature range is milder and can avoid the collapse of the lithium manganese oxide core structure or excessive migration / doping of transition metal ions.

[0154] Specifically, the powder can be dried in a forced-air drying oven at 70℃~80℃ until it reaches a constant weight. Then, the dried powder is placed in a tube furnace or atmosphere box furnace, nitrogen is first introduced to purge the air, and then the temperature is raised to 450℃~550℃ (e.g., 500℃) at a certain heating rate. After holding at this temperature for a period of time, the powder is cooled with the furnace.

[0155] In some implementations, step S3 includes:

[0156] S31, lithium manganese oxide and PVDF particles coated with the first coating layer are fused using a high-speed mechanical fusion method, and then sintered and cooled at high temperature to obtain the composite lithium manganese oxide cathode material.

[0157] The aforementioned high-speed mechanical fusion is the physical coating stage of the second coating layer.

[0158] The lithium manganese oxide intermediate, which has already formed the first coating layer in the previous step, is mixed with the second coating layer material (PVDF particles) in a certain proportion. Dry processing is then performed using the mechanical force generated by a high-speed mechanical fusion device. This method differs from liquid-phase coating; it utilizes the impact, shear, and friction forces generated by high-speed rotation to forcibly "nail" or compact the softer PVDF particles onto or onto the surface of the harder first coating layer particles. Thus, the PVDF particles are tightly adhered to the surface of the first coating layer through mechanical interlocking or physical adsorption, forming the initial second coating layer structure.

[0159] This step uses a dry coating technique, which does not require the use of organic solvents. The process is simple and environmentally friendly; it can quickly achieve the composite between powders, laying a good physical contact foundation for subsequent chemical bonding.

[0160] Specifically, a high-speed mechanical fusion machine can be used to feed the mixed powder into the equipment and process it by setting a specific speed and time.

[0161] The above-mentioned high-temperature sintering and cooling process to obtain the composite lithium manganese oxide cathode material is the thermal curing and chemical modification stage of the second coating layer.

[0162] High-temperature sintering involves heat-treating the mechanically fused powder at a high temperature. Although the claims do not specify a particular temperature, the embodiment mentioned in the specification is 550°C. At this temperature, PVDF will soften or melt and flow. After sintering, the temperature is lowered to allow the molten or softened PVDF to re-solidify and set.

[0163] Through the above steps, PVDF forms a more uniform, dense, and firmly bonded thin film or granular layer on the surface of the first coating layer. High temperature promotes the Lewis acid-base reaction between oxygen vacancies (Lewis acids) in the first coating layer and fluorine elements (which provide electrons) in the PVDF, enhancing the interlayer bonding force. Fluorine elements adsorb free lithium ions to form LiF, creating a gradient distribution with high lithium concentration in the inner layer and low lithium concentration in the outer layer.

[0164] The sintered PVDF layer exhibits excellent chemical stability and electrochemical inertness, effectively isolating the core from electrolyte corrosion. This ensures the finalization of the double-layer core-shell structure and improves the material's structural stability, cycle performance, and safety.

[0165] Specifically, the mechanically fused material can be placed in a sintering furnace, heated to a predetermined temperature (e.g., 550°C) in air or a protective atmosphere, held at that temperature for a certain time (e.g., 3 hours), and then cooled to room temperature with the furnace.

[0166] In this application embodiment, an electrode is provided, comprising the aforementioned composite lithium manganese oxide cathode material, or comprising a composite lithium manganese oxide cathode material obtained by the aforementioned method for preparing the composite lithium manganese oxide cathode material.

[0167] The aforementioned electrode is the positive electrode (or cathode) used in lithium-ion batteries. Its core feature is that it utilizes the aforementioned composite lithium manganese oxide positive electrode material as its electrochemical active material. A complete electrode suitable for battery assembly, in addition to this core active material, typically includes, but is not limited to, the following components:

[0168] (1) Conductive agent: Since the conductivity of the positive electrode active material itself is limited, it is usually necessary to add conductive agents (such as conductive carbon black, acetylene black, carbon nanotubes, etc.) to build an electronic conductive network to ensure that the current can be efficiently transmitted inside the electrode.

[0169] (2) Adhesive: In order to firmly bond the powdered active material and conductive agent together and make them adhere tightly to the metal current collector, a polymer adhesive (such as polyvinylidene fluoride PVDF, SBR, etc.) is required.

[0170] (3) Current collector: Usually a metal foil, which serves as the substrate for carrying the active material coating and is responsible for collecting current and guiding it into the external circuit of the battery. For the positive electrode, aluminum foil is usually used as the current collector.

[0171] In the preparation process, the aforementioned composite lithium manganese oxide cathode material, conductive agent, and binder can be mixed in a specific solvent to form a uniform slurry. This slurry is then uniformly coated onto an aluminum foil current collector, and after drying, rolling, and other processes, the electrode sheet is finally formed. The advantages and beneficial effects of this electrode are directly inherited from the composite lithium manganese oxide cathode material used, such as higher structural stability and potentially superior electrochemical performance.

[0172] In this application embodiment, a battery is provided, including electrodes as described in the foregoing embodiments.

[0173] The aforementioned battery employs an electrode containing a novel composite lithium manganese oxide positive electrode material, as defined in the preceding embodiments. This electrode, along with key components such as the negative electrode, separator, and electrolyte, is encapsulated within a housing to form a fully functional lithium-ion battery cell. Depending on the packaging form and application scenario, this lithium-ion battery can be of various types, including cylindrical, pouch, or prismatic, and can be used as a power battery in electric bicycles, new energy vehicles, and other transportation vehicles, or as an energy storage battery in power grid systems.

[0174] In this application embodiment, an electrical device is provided, including a battery as described in the foregoing embodiments.

[0175] The aforementioned electrical equipment or devices utilize the batteries described in the preceding embodiments as their energy source; therefore, the performance advantages of these devices directly benefit from the superior performance of their built-in batteries. Their specific applications cover multiple fields, such as transportation vehicles, including pure electric vehicles, electric bicycles, and electric forklifts; energy storage systems, including large power grid sites, home energy storage walls, and portable emergency power supplies; furthermore, they can be applied to various wireless electric tools and automated equipment requiring high power output, such as inspection robots and drones.

[0176] The present invention will be further illustrated below with specific embodiments. However, it should be understood that these embodiments are merely for the purpose of more detailed illustration and should not be construed as limiting the present invention in any way.

[0177] Table 1. Key parameters in the embodiments

[0178]

[0179] Example 1

[0180] The cathode material prepared in this embodiment has a core-shell structure.

[0181] The cathode material is based on lithium manganese oxide as the core, with a composite coating layer as the shell. The composite coating layer coats the surface of the lithium manganese oxide and includes a first coating layer, CuCe, disposed on the surface of the lithium manganese oxide. xFe 2-x O4-0%Li, and a second coating layer disposed on the surface of the first coating layer. Particles and;

[0182] Experimental methods: Some parameters can be found in Table 1.

[0183] S1, Preparation of CuCe x Fe 2-x O4-yLi particles:

[0184] (1) Weigh copper nitrate, cerium nitrate and ferric nitrate in a metal element molar ratio of 1:0.1:1.9 and place them in a container. Add 10 mL of ultrapure water and stir until completely dissolved to obtain a mixture.

[0185] (2) Add 30wt% ammonia water to the mixture and stir continuously for 1.0~2.0h to obtain a precipitate with pH=9.

[0186] (3) After the precipitate is completely sealed in a high-pressure autoclave, it is placed in a heating furnace at 130°C for 4 hours and then cooled to room temperature to obtain a solid product.

[0187] (4) The solid product was filtered under reduced pressure and washed with ultrapure water until pH=7. The precipitate was separated by vacuum filtration and dried at 70℃ for 8 hours to obtain solid powder.

[0188] (5) The solid powder was heated at a rate of 5℃ / min in a furnace at 500℃ for 5 hours, and then cooled with the furnace. This process yielded a spinel-type product with good crystallinity, CuCe. 0.1 Fe 1.9 O4.

[0189] S2. The product obtained in step S1 was dispersed in ethanol, and lithium manganese oxide was added to the solution. The mixture was then wet-milled in a star mill at 100 rpm for 3 hours. After drying, it was placed in a muffle furnace and heat-treated at 500℃ for 6 hours to obtain CuCe. 0.1 Fe 1.9 O4-coated lithium manganese oxide cathode material, in which CuCe 0.1 Fe 1.9 The mass fraction of O4 is 1%wt;

[0190] S3, CuCe 0.1 Fe 1.9 O4-coated lithium manganese oxide and PVDF particles were fused using a high-speed mechanical fusion method and then sintered at 550°C for 3 hours to obtain a composite lithium manganese oxide cathode material, wherein the second coating layer accounts for 1 wt% of the mass fraction of the lithium manganese oxide.

[0191] Example 2

[0192] The cathode material prepared in this embodiment has a core-shell composite structure.

[0193] The cathode material is based on lithium manganese oxide as the core, with a composite coating layer as the shell. The composite coating layer coats the surface of the lithium manganese oxide and includes a first coating layer, CuCe, disposed on the surface of the lithium manganese oxide. x Fe 2-x O4-1%Li, and a second coating layer disposed on the surface of the first coating layer. Particles;

[0194] Experimental methods: Some parameters can be found in Table 1.

[0195] (1) Weigh copper nitrate, cerium nitrate and iron nitrate in a metal element molar ratio of 1:0.1:1.9 and place them in a container. Add 10 mL of ultrapure water and stir until completely dissolved. Then add 1 wt% lithium nitrate to obtain a mixed solution.

[0196] (2) Add 30wt% ammonia water to the mixture and stir continuously for 1.0~2.0h to obtain a precipitate with pH=9.

[0197] (3) After the precipitate is completely sealed in a high-pressure autoclave, it is placed in a heating furnace at 130°C for 4 hours and then cooled to room temperature to obtain a solid product.

[0198] (4) The solid product was filtered under reduced pressure and washed with ultrapure water until pH=7. The precipitate was separated by vacuum filtration and dried at 70℃ for 8 hours to obtain solid powder.

[0199] (5) The solid powder was heated at a rate of 5℃ / min in a furnace at 500℃ for 5 hours, and then cooled with the furnace. This process yielded a spinel-type product with good crystallinity, CuCe. 0.1 Fe 1.9 O4-1% Li.

[0200] S2. The product obtained in step S1 was dispersed in ethanol, and lithium manganese oxide was added to the solution. The mixture was then wet-milled in a star mill at 100 rpm for 3 hours. After drying, it was placed in a muffle furnace and heat-treated at 500℃ for 6 hours to obtain CuCe. 0.1 Fe 1.9 O4-1% Li-coated lithium manganese oxide cathode material, wherein CuCe 0.1 Fe 1.9 The mass fraction of O4-1% Li is 1%wt;

[0201] S3, CuCe 0.1 Fe 1.9O4-1% Li-coated lithium manganese oxide and PVDF particles were fused using a high-speed mechanical fusion method and then sintered at 550℃ for 3 hours to obtain a composite lithium manganese oxide cathode material, wherein the second coating layer accounts for 1 wt% of the mass fraction of the lithium manganese oxide.

[0202] Example 3

[0203] The cathode material prepared in this embodiment has a core-shell composite structure.

[0204] The cathode material is based on lithium manganese oxide as the core, with a composite coating layer as the shell. The composite coating layer coats the surface of the lithium manganese oxide and includes a first coating layer, CuCe, disposed on the surface of the lithium manganese oxide. x Fe 2-x O4-2%Li, and a second coating layer disposed on the surface of the first coating layer. Particles;

[0205] Experimental methods: Some parameters can be found in Table 1.

[0206] (1) Weigh copper nitrate, cerium nitrate and iron nitrate in a metal element molar ratio of 1:0.1:1.9 and place them in a container. Add 10 mL of ultrapure water and stir until completely dissolved. Then add 2 wt% lithium nitrate to obtain a mixed solution.

[0207] (2) Add 30wt% ammonia water to the mixture and stir continuously for 1.0~2.0h to obtain a precipitate with pH=9.

[0208] (3) After the precipitate is completely sealed in a high-pressure autoclave, it is placed in a heating furnace at 130°C for 4 hours and then cooled to room temperature to obtain a solid product.

[0209] (4) The solid product was filtered under reduced pressure and washed with ultrapure water until pH=7. The precipitate was separated by vacuum filtration and dried at 70℃ for 8 hours to obtain solid powder.

[0210] (5) The solid powder was heated at a rate of 5℃ / min in a furnace at 500℃ for 5 hours, and then cooled with the furnace. This process yielded a spinel-type product with good crystallinity, CuCe. 0.1 Fe 1.9 O4-2% Li.

[0211] S2. The product obtained in step S1 was dispersed in ethanol, and lithium manganese oxide was added to the solution. The mixture was then wet-milled in a star mill at 100 rpm for 3 hours. After drying, it was placed in a muffle furnace and heat-treated at 500℃ for 6 hours to obtain CuCe. 0.1 Fe 1.9 O4-2% coated lithium manganese oxide cathode material, of which CuCe 0.1Fe 1.9 The mass fraction of O4-2% Li is 1%wt;

[0212] S3, CuCe 0.1 Fe 1.9 O4-2% Li-coated lithium manganese oxide and PVDF particles were fused using a high-speed mechanical fusion method and then sintered at 550℃ for 3 hours to obtain a composite lithium manganese oxide cathode material, wherein the second coating layer accounts for 1 wt% of the mass fraction of the lithium manganese oxide.

[0213] Example 4

[0214] The cathode material prepared in this embodiment has a core-shell composite structure.

[0215] The cathode material is based on lithium manganese oxide as the core, with a composite coating layer as the shell. The composite coating layer coats the surface of the lithium manganese oxide and includes a first coating layer, CuCe, disposed on the surface of the lithium manganese oxide. x Fe 2-x O4-3%Li, and a second coating layer disposed on the surface of the first coating layer. Particles;

[0216] Experimental methods: Some parameters can be found in Table 1.

[0217] (1) Weigh copper nitrate, cerium nitrate and iron nitrate in a metal element molar ratio of 1:0.1:1.9 and place them in a container. Add 10 mL of ultrapure water and stir until completely dissolved. Then add 3 wt% lithium nitrate to obtain a mixture.

[0218] (2) Add 30wt% ammonia water to the mixture and stir continuously for 1.0~2.0h to obtain a precipitate with pH=9.

[0219] (3) After the precipitate is completely sealed in a high-pressure autoclave, it is placed in a heating furnace at 130°C for 4 hours and then cooled to room temperature to obtain a solid product.

[0220] (4) The solid product was filtered under reduced pressure and washed with ultrapure water until pH=7. The precipitate was separated by vacuum filtration and dried at 70℃ for 8 hours to obtain solid powder.

[0221] (5) The solid powder was heated at a rate of 5℃ / min in a furnace at 500℃ for 5 hours, and then cooled with the furnace. This process yielded a spinel-type product with good crystallinity, CuCe. 0.1 Fe 1.9 O4-3% Li.

[0222] S2. The product obtained in step S1 was dispersed in ethanol, and lithium manganese oxide was added to the solution. The mixture was then wet-milled in a star mill at 100 rpm for 3 hours. After drying, it was placed in a muffle furnace and heat-treated at 500℃ for 6 hours to obtain CuCe. 0.1 Fe 1.9 O4-3% Li-coated lithium manganese oxide cathode material, wherein CuCe 0.1 Fe 1.9 The mass fraction of O4-3% Li is 1%wt;

[0223] S3, CuCe 0.1 Fe 1.9 O4-3% Li-coated lithium manganese oxide and PVDF particles were fused using a high-speed mechanical fusion method and then sintered at 550℃ for 3 hours to obtain a composite lithium manganese oxide cathode material, wherein the second coating layer accounts for 1 wt% of the mass fraction of the lithium manganese oxide.

[0224] Example 5

[0225] The cathode material prepared in this embodiment has a core-shell composite structure.

[0226] The cathode material is based on lithium manganese oxide as the core, with a composite coating layer as the shell. The composite coating layer coats the surface of the lithium manganese oxide and includes a first coating layer, CuCe, disposed on the surface of the lithium manganese oxide. x Fe 2-x O4-4%Li, and a second coating layer disposed on the surface of the first coating layer. Particles;

[0227] Experimental methods: Some parameters can be found in Table 1.

[0228] (1) Weigh copper nitrate, cerium nitrate and iron nitrate in a metal element molar ratio of 1:0.1:1.9 and place them in a container. Add 10 mL of ultrapure water and stir until completely dissolved. Then add 4 wt% lithium nitrate to obtain a mixture.

[0229] (2) Add 30wt% ammonia water to the mixture and stir continuously for 1.0~2.0h to obtain a precipitate with pH=9.

[0230] (3) After the precipitate is completely sealed in a high-pressure autoclave, it is placed in a heating furnace at 130°C for 4 hours and then cooled to room temperature to obtain a solid product.

[0231] (4) The solid product was filtered under reduced pressure and washed with ultrapure water until pH=7. The precipitate was separated by vacuum filtration and dried at 70℃ for 8 hours to obtain solid powder.

[0232] (5) The solid powder was heated at a rate of 5℃ / min in a furnace at 500℃ for 5 hours, and then cooled with the furnace. This process yielded a spinel-type product with good crystallinity, CuCe. 0.1 Fe 1.9 O4-4% Li.

[0233] S2. The product obtained in step S1 was dispersed in ethanol, and lithium manganese oxide was added to the solution. The mixture was then wet-milled in a star mill at 100 rpm for 3 hours. After drying, it was placed in a muffle furnace and heat-treated at 550℃ for 6 hours to obtain CuCe. 0.1 Fe 1.9 O4-4% Li-coated lithium manganese oxide cathode material, wherein CuCe 0.1 Fe 1.9 The mass fraction of O4-4% Li is 1%wt;

[0234] S3, CuCe 0.1 Fe 1.9 O4-4% Li-coated lithium manganese oxide and PVDF particles were fused using a high-speed mechanical fusion method and then sintered at 500℃ for 3 hours to obtain a composite lithium manganese oxide cathode material, wherein the second coating layer accounts for 1 wt% of the mass fraction of the lithium manganese oxide.

[0235] Example 6

[0236] The cathode material prepared in this embodiment has a core-shell composite structure.

[0237] The cathode material is based on lithium manganese oxide as the core, with a composite coating layer as the shell. The composite coating layer coats the surface of the lithium manganese oxide and includes a first coating layer, CuCe, disposed on the surface of the lithium manganese oxide. x Fe 2-x O4-5%Li, and a second coating layer disposed on the surface of the first coating layer. Particles;

[0238] Experimental methods: Some parameters can be found in Table 1.

[0239] (1) Weigh copper nitrate, cerium nitrate and iron nitrate in a metal element molar ratio of 1:0.1:1.9 and place them in a container. Add 10 mL of ultrapure water and stir until completely dissolved. Then add 5 wt% lithium nitrate to obtain a mixed solution.

[0240] (2) Add 30wt% ammonia water to the mixture and stir continuously for 1.0~2.0h to obtain a precipitate with pH=9.

[0241] (3) After the precipitate is completely sealed in a high-pressure autoclave, it is placed in a heating furnace at 130°C for 4 hours and then cooled to room temperature to obtain a solid product.

[0242] (4) The solid product was filtered under reduced pressure and washed with ultrapure water until pH=7. The precipitate was separated by vacuum filtration and dried at 70℃ for 8 hours to obtain solid powder.

[0243] (5) The solid powder was heated at a rate of 5℃ / min in a furnace at 500℃ for 5 hours, and then cooled with the furnace. This process yielded a spinel-type product with good crystallinity, CuCe. 0.1 Fe 1.9 O4-5%Li.

[0244] S2. The product obtained in step S1 was dispersed in ethanol, and lithium manganese oxide was added to the solution. The mixture was then wet-milled in a star mill at 100 rpm for 3 hours. After drying, it was placed in a muffle furnace and heat-treated at 550℃ for 6 hours to obtain CuCe. 0.1 Fe 1.9 O4-5% Li-coated lithium manganese oxide cathode material, including CuCe 0.1 Fe 1.9 The mass fraction of O4-5%Li is 5%wt;

[0245] S3, CuCe 0.1 Fe 1.9 O4-5%Li coated lithium manganese oxide and PVDF particles were fused using a high-speed mechanical fusion method and then sintered at 500℃ for 3 hours to obtain a composite lithium manganese oxide cathode material, wherein the second coating layer accounts for 1 wt% of the mass fraction of the lithium manganese oxide.

[0246] Example 7

[0247] The cathode material prepared in this embodiment has a core-shell composite structure.

[0248] The cathode material is based on lithium manganese oxide as the core, with a composite coating layer as the shell. The composite coating layer coats the surface of the lithium manganese oxide and includes a first coating layer, CuCe, disposed on the surface of the lithium manganese oxide. 0.1 Fe 1.9 O4-2%Li, and a second coating layer disposed on the surface of the first coating layer. Particles;

[0249] Experimental methods: Some parameters can be found in Table 1.

[0250] (1) Weigh copper nitrate, cerium nitrate and iron nitrate in a metal element molar ratio of 1:0.1:1.9 and place them in a container. Add 10 mL of ultrapure water and stir until completely dissolved. Then add 2 wt% lithium nitrate to obtain a mixed solution.

[0251] (2) Add 30wt% ammonia water to the mixture and stir continuously for 1.0~2.0h to obtain a precipitate with pH=9.

[0252] (3) After the precipitate is completely sealed in a high-pressure autoclave, it is placed in a heating furnace at 130°C for 4 hours and then cooled to room temperature to obtain a solid product.

[0253] (4) The solid product was filtered under reduced pressure and washed with ultrapure water until pH=7. The precipitate was separated by vacuum filtration and dried at 70℃ for 8 hours to obtain solid powder.

[0254] (5) The solid powder was heated at a rate of 5℃ / min in a furnace at 500℃ for 5 hours, and then cooled with the furnace. This process yielded a spinel-type product with good crystallinity, CuCe. 0.1 Fe 1.9 O4-2%Li.

[0255] S2. The product obtained in step S1 was dispersed in ethanol, and lithium manganese oxide was added to the solution. The mixture was then wet-milled in a star mill at 100 rpm for 3 hours. After drying, it was placed in a muffle furnace and heat-treated at 550℃ for 6 hours to obtain CuCe. 0.1 Fe 1.9 O4-2% Li-coated lithium manganese oxide cathode material, wherein CuCe 0.1 Fe 1.9 The mass fraction of O4-2%Li is 3%wt;

[0256] S3, CuCe 0.1 Fe 1.9 O4-2%Li coated lithium manganese oxide and PVDF particles were fused using a high-speed mechanical fusion method and then sintered at 500℃ for 3 hours to obtain a composite lithium manganese oxide cathode material, wherein the second coating layer accounts for 3wt% of the mass fraction of the lithium manganese oxide.

[0257] Example 8

[0258] The cathode material prepared in this embodiment has a core-shell composite structure.

[0259] The cathode material is based on lithium manganese oxide as the core, with a composite coating layer as the shell. The composite coating layer coats the surface of the lithium manganese oxide and includes a first coating layer, CuCe, disposed on the surface of the lithium manganese oxide. 0.1 Fe 1.9 O4-2%Li, and a second coating layer disposed on the surface of the first coating layer. Particles;

[0260] Experimental methods: Some parameters can be found in Table 1.

[0261] (1) Weigh copper nitrate, cerium nitrate and iron nitrate in a metal element molar ratio of 1:0.1:1.9 and place them in a container. Add 10 mL of ultrapure water and stir until completely dissolved. Then add 2 wt% lithium nitrate to obtain a mixed solution.

[0262] (2) Add 30wt% ammonia water to the mixture and stir continuously for 1.0~2.0h to obtain a precipitate with pH=9.

[0263] (3) After the precipitate is completely sealed in a high-pressure autoclave, it is placed in a heating furnace at 130°C for 4 hours and then cooled to room temperature to obtain a solid product.

[0264] (4) The solid product was filtered under reduced pressure and washed with ultrapure water until pH=7. The precipitate was separated by vacuum filtration and dried at 70℃ for 8 hours to obtain solid powder.

[0265] (5) The solid powder was heated at a rate of 5℃ / min in a furnace at 500℃ for 5 hours, and then cooled with the furnace. This process yielded a spinel-type product with good crystallinity, CuCe. 0.1 Fe 1.9 O4-2%Li.

[0266] S2. The product obtained in step S1 was dispersed in ethanol, and lithium manganese oxide was added to the solution. The mixture was then wet-milled in a star mill at 100 rpm for 3 hours. After drying, it was placed in a muffle furnace and heat-treated at 550℃ for 6 hours to obtain CuCe. 0.1 Fe 1.9 O4-2%Li coated lithium manganese oxide cathode material, wherein CuCe 0.1 Fe 1.9 The mass fraction of O4-2%Li is 5%wt;

[0267] S3, CuCe 0.1 Fe 1.9 O4-2%Li coated lithium manganese oxide and PVDF particles were fused using a high-speed mechanical fusion method and then sintered at 500℃ for 3 hours to obtain a composite lithium manganese oxide cathode material, wherein the second coating layer accounts for 5wt% of the mass fraction of the lithium manganese oxide.

[0268] Example 9

[0269] The cathode material prepared in this embodiment has a core-shell composite structure.

[0270] The cathode material is based on lithium manganese oxide as the core, with a composite coating layer as the shell. The composite coating layer coats the surface of the lithium manganese oxide and includes a first coating layer, CuCe, disposed on the surface of the lithium manganese oxide. 0.2 Fe 1.8O4-2%Li, and a second coating layer disposed on the surface of the first coating layer. Particles;

[0271] Experimental methods: Some parameters can be found in Table 1.

[0272] (1) Weigh copper nitrate, cerium nitrate and iron nitrate in a metal element molar ratio of 1:0.2:1.8 and place them in a container. Add 10 mL of ultrapure water and stir until completely dissolved. Then add 2 wt% lithium nitrate to obtain a mixed solution.

[0273] (2) Add 30wt% ammonia water to the mixture and stir continuously for 1.0~2.0h to obtain a precipitate with pH=9.

[0274] (3) After the precipitate is completely sealed in a high-pressure autoclave, it is placed in a heating furnace at 130°C for 4 hours and then cooled to room temperature to obtain a solid product.

[0275] (4) The solid product was filtered under reduced pressure and washed with ultrapure water until pH=7. The precipitate was separated by vacuum filtration and dried at 70℃ for 8 hours to obtain solid powder.

[0276] (5) The solid powder was heated at a rate of 5℃ / min in a furnace at 500℃ for 5 hours, and then cooled with the furnace. This process yielded a spinel-type product with good crystallinity, CuCe. 0.2 Fe 1.8 O4-2%Li.

[0277] S2. The product obtained in step S1 was dispersed in ethanol, and lithium manganese oxide was added to the solution. The mixture was then wet-milled in a star mill at 100 rpm for 3 hours. After drying, it was placed in a muffle furnace and heat-treated at 550℃ for 6 hours to obtain CuCe. 0.2 Fe 1.8 O4-2%Li coated lithium manganese oxide cathode material, wherein CuCe 0.2 Fe 1.8 The mass fraction of O4-2%Li is 5%wt;

[0278] S3, CuCe 0.2 Fe 1.8 O4-2%Li coated lithium manganese oxide and PVDF particles were fused using a high-speed mechanical fusion method and then sintered at 500℃ for 3 hours to obtain a composite lithium manganese oxide cathode material, wherein the second coating layer accounts for 5wt% of the mass fraction of the lithium manganese oxide.

[0279] Example 10

[0280] This embodiment is used to verify the material properties when the Ce element content is high (x=0.8) to support the upper limit of the range of x values ​​in the claims.

[0281] The specific preparation method is the same as in Example 3, except that the ratio of cerium nitrate and ferrous nitrate in step S1 is adjusted. Specifically, cerium nitrate and ferrous nitrate are weighed according to the stoichiometric ratio Ce:Fe = 0.8:1.2, while the ratios of the remaining copper and lithium sources remain unchanged, thus preparing a product with the composition CuCe. 0.8 Fe 1.2 The first coating layer of O4-yLi.

[0282] The remaining steps (S2, S3) and parameters are exactly the same as in Example 3.

[0283] Comparative Example 1

[0284] The cathode material prepared in Comparative Example 1 has a core-shell composite structure.

[0285] The cathode material is based on lithium manganese oxide as the core, with a composite coating layer as the shell. The composite coating layer coats the surface of the lithium manganese oxide and includes a first coating layer, CuCe, disposed on the surface of the lithium manganese oxide. x Fe 2-x O4-1%Li.

[0286] Experimental methods: Some parameters can be found in Table 1.

[0287] (1) Weigh copper nitrate, cerium nitrate and iron nitrate in a metal element molar ratio of 1:0.1:1.9 and place them in a container. Add 10 mL of ultrapure water and stir until completely dissolved. Then add 1 wt% lithium nitrate to obtain a mixed solution.

[0288] (2) Add 30wt% ammonia water to the mixture and stir continuously for 1.0~2.0h to obtain a precipitate with pH=9.

[0289] (3) After the precipitate is completely sealed in a high-pressure autoclave, it is placed in a heating furnace at 130°C for 4 hours and then cooled to room temperature to obtain a solid product.

[0290] (4) The solid product was filtered under reduced pressure and washed with ultrapure water until pH=7. The precipitate was separated by vacuum filtration and dried at 70℃ for 8 hours to obtain solid powder.

[0291] (5) The solid powder was heated at a rate of 5℃ / min in a furnace at 500℃ for 5 hours, and then cooled with the furnace. This process yielded a spinel-type product with good crystallinity, CuCe. 0.1 Fe 1.9 O4-1% Li.

[0292] S2. The product obtained in step S1 was dispersed in ethanol, and lithium manganese oxide was added to the solution. The mixture was then wet-milled in a star mill at 100 rpm for 3 hours. After drying, it was placed in a muffle furnace and heat-treated at 550℃ for 6 hours to obtain CuCe. 0.1 Fe 1.9 O4-1% Li-coated lithium manganese oxide cathode material, wherein CuCe 0.1 Fe 1.9 The mass fraction of O4-1% Li is 1%wt;

[0293] Comparative Example 2

[0294] The cathode material prepared in this embodiment has a core-shell composite structure.

[0295] The positive electrode material is based on lithium manganese oxide as the core, with a composite coating layer on the shell. This composite coating layer coats the surface of the lithium manganese oxide. Particles;

[0296] Experimental methods: Some parameters can be found in Table 1.

[0297] Lithium manganese oxide and PVDF particles were fused using a high-speed mechanical fusion method and then sintered at 500℃ for 3 hours to obtain a composite lithium manganese oxide cathode material.

[0298] Comparative Example 3

[0299] This comparative example is used to verify the material properties when the first coating layer does not contain Ce (i.e., x=0).

[0300] The specific preparation method is the same as in Example 3, except that: in the raw material ratio of step S1, cerium nitrate (Ce source) was not added, and the amount of ferrous nitrate was adjusted to an equimolar amount (i.e., the number of Fe moles is equal to the total number of Fe+Ce moles in Example 3) to prepare the first coating layer with the composition CuFe2O4-yLi.

[0301] The remaining steps (S2, S3) and parameters are exactly the same as in Example 3.

[0302] Comparative Example 4

[0303] This comparative example is used to compare the performance of the original lithium manganese oxide material without any coating modification, in order to highlight the advancement of the coating technology of this application.

[0304] The same batch of lithium manganese oxide raw material described in step S1 of Example 1 was directly selected as the positive electrode active material, without any subsequent coating treatment steps.

[0305] They were prepared into electrodes using the same process and assembled into 15119 model batteries for testing.

[0306] Test experiment:

[0307] 1. Experimental Method:

[0308] The composite lithium manganese oxide cathode materials obtained in Examples 1-9 and the composite lithium manganese oxide cathode materials obtained in Comparative Examples 1-2 were tested for lithium-ion diffusion coefficient and electronic conductivity. The lithium-ion diffusion coefficient was tested in accordance with the industry standard "Test Method for Lithium-ion Diffusion Coefficient of Lithium-ion Battery Materials" (2022-1337T-SJ), and the electronic conductivity was tested using a conductivity meter. The results are shown in Table 1.

[0309] 2. Experimental Results and Analysis:

[0310] Table 2. Test Results

[0311]

[0312] Table 3. Cycle Retention Rate Test

[0313]

[0314] Combining Table 2, Table 3, and Figure 4 The XRD test results are used to analyze the embodiments and comparative examples of this application as follows:

[0315] (1) Regarding the effect of lithium doping on ion transport (comparison of Example 1 and Examples 2-6): As can be seen from the data in Tables 2 and 3, although Example 1 (without lithium, y=0) has a higher high-temperature cycle retention rate (86.1%) than Comparative Example 3 (without Ce, 83.5%) due to its double-shell structure and the introduction of Ce, demonstrating the contribution of Ce-induced oxygen vacancies to structural stability, compared with Examples 2-6 (containing lithium, y=1%~5%), the electronic conductivity, lithium-ion diffusion coefficient, and cycle retention rate of Example 1 are all lower than those of the subsequent lithium-containing examples.

[0316] Specifically, when 1% lithium doping was introduced (Example 2), the high-temperature cycle retention rate further increased from 86.1% to 89.2%. The underlying reason is that when CuCe... x Fe 2-x After lithium doping of the O4 spinel structure, the smaller Li... + It can enter the spinel lattice, occupy the tetrahedral interstitial space, or replace part of the Cu. 2+ This not only forms a highly efficient Li-O-Fe / Ce ion channel, but also reduces the Li... +The migration energy barrier (increases the diffusion coefficient) is improved; more importantly, the formed Li-O chemical bond has a high bond energy, which further suppresses the lattice breathing effect caused by the transition metal valence change during charging and discharging, thereby significantly improving the structural stability of the material during long-term cycling. This fully demonstrates the necessity and technological advantages of lithium doping in the range of 0% to 5%.

[0317] (2) Regarding the synergistic effect of the double-layer coating structure (comparison of Example 2 with Comparative Examples 1 and 2): The cycling performance and rate performance of Comparative Example 1 (only the first coating layer) are weaker than those of Example 2, indicating that the second coating layer PVDF is indispensable. The PVDF layer not only serves as a protective barrier, but the fluorine on its surface can also adsorb free lithium ions to form LiF, creating a lithium concentration gradient of "low outside and high inside", which significantly promotes ion diffusion.

[0318] The high-temperature performance and structural stability of Comparative Example 2 (PVDF layer only) are significantly worse than those of Example 2, indicating that the first coating layer CuCe x Fe 2-x O4 plays a crucial role in providing skeletal support. This spinel layer is isomorphic to the lithium manganese oxide core structure, effectively reducing interfacial impedance; moreover, the high Li-O bond energy effectively suppresses the lattice breathing effect during charging and discharging, preventing the collapse of the lithium manganese oxide core.

[0319] (3) Regarding the key role of Ce element and oxygen vacancies (Comparison of Examples 3 and 10 with Comparative Example 3):

[0320] Comparative Example 3, where Ce was not doped in the first coating layer (x=0), showed a high electronic conductivity (1.6×10⁻⁶). -6 Both the S / cm and cycle retention rates were significantly lower than those of Examples 3 and 10, which contained Ce. This fully demonstrates the crucial role of the introduction of Ce: the variable valence of Ce induces oxygen vacancies in the crystal lattice. These oxygen vacancies not only directly enhance the electronic conductivity of the material but also act as Lewis acid sites, interacting strongly with the electron-rich fluorine (Lewis base) in the outer PVDF. This chemical bonding significantly strengthens the bond between the inner and outer shells, preventing the coating from detaching during long cycles and thus ensuring excellent cycling stability.

[0321] (4) Regarding the broad applicability of the Ce content range (comparison between Example 9 and Example 10): Comparing Example 9 (x=0.2, low Ce content) and Example 10 (x=0.8, high Ce content), both exhibit excellent and similar electrochemical performance (electronic conductivity greater than 3.0×10⁻⁶). -6(S / cm, room temperature cycling retention rate is above 92%). This strongly supports the broad applicability of x values ​​in the claim within the range of 0 to 1 (excluding 0), proving that Ce can play a role in stabilizing the crystal lattice and improving conductivity regardless of whether it is low-doped or high-doped.

[0322] (5) Regarding the significant advancements of the technical solution of this application compared to the prior art (comparison of Comparative Example 4 and various embodiments):

[0323] Comparative Example 4 is pure lithium manganese oxide without any coating or modification, and its various performance indicators (electronic conductivity is only 5.0 × 10⁻⁶) are as follows: -7 The S / cm and high-temperature cycle retention rate (only 60.5%) were the lowest among all groups. This clearly reveals the inherent defects of traditional lithium manganese oxide materials, such as poor conductivity and severe manganese leaching. However, the embodiments of this application, by constructing a double-layer structure of "lithium manganese oxide core - lithium-doped polymetallic oxide inner shell - PVDF outer shell," significantly improved the high-temperature cycle retention rate from around 60% to over 88%, achieving a qualitative leap in the performance of the cathode material.

[0324] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite lithium manganese oxide cathode material, characterized in that, The composite lithium manganese oxide cathode material has a core-shell structure; its core is lithium manganese oxide, and its shell is a composite coating layer covering the surface of lithium manganese oxide. The composite coating layer includes a first coating layer and a second coating layer that are sequentially coated from the inside out; The chemical formula of the first cladding layer is CuCe x Fe 2-x O4-yLi; wherein, 0≤x≤1, y represents the mass fraction of the doped lithium source, and y is 0% to 5%. The second coating layer comprises PVDF particles.

2. The composite lithium manganate cathode material of claim 1, wherein, The first coating layer comprises 1 wt% to 5 wt% of the lithium manganese oxide by mass; and / or, The second coating layer comprises 1 wt% to 5 wt% of the lithium manganese oxide by mass; and / or, In the first cladding layer, CuCe x Fe 2-x The particle size of the O4-yLi particles is 0.2 μm-~1 μm; and / or, In the second coating layer, the PVDF particles have a particle size of 0.1~1μm.

3. A method of preparing the composite lithium manganate cathode material according to claim 1 or 2, characterized in that, include: S1, preparing CuCe x Fe 2-x O4-yLi particles; S2, CuCe x Fe 2-x O4-yLi particles are coated on the surface of lithium manganese oxide to form the first coating layer; S3. A second coating layer is formed on the surface of the first coating layer to form the composite lithium manganese oxide cathode material.

4. The preparation method of the composite lithium manganese oxide cathode material as described in claim 3, characterized in that, The CuCe x Fe 2-x The method for preparing O4-yLi particles includes: The metal nitrates of Cu, Ce and Fe were weighed in a metal element molar ratio of 1:x:(2-x) and placed in a container. Li nitrate with a mass fraction of y was added and water was added and stirred until dissolved to obtain a mixed solution, wherein y is 0%~5%. Ammonia water was added to the mixture and stirred continuously to obtain a precipitate with pH=7~13; The precipitate was filtered under reduced pressure and washed with ultrapure water until the pH reached 6-8. The precipitate was then separated by vacuum filtration and dried to obtain a solid powder. The solid powder is subjected to a crystallization treatment to obtain a target product, i.e., CuCe, with good crystallinity x Fe 2-x O4-y%Li.

5. The preparation method of the composite lithium manganese oxide cathode material as described in claim 4, characterized in that, The stirring time is 1 to 2 hours; and / or, The crystallization treatment temperature is 300℃~600℃; and / or, The temperature rise rate for the crystallization treatment is 3℃ / min to 10℃ / min; and / or, The holding time for the crystallization treatment is 2h~5h; and / or, The cooling rate of the crystallization process is natural cooling within the furnace.

6. The method for preparing the composite lithium manganese oxide cathode material as described in claim 3, characterized in that, The method for forming the first coating layer includes: CuCe x Fe 2-x O4-y%Li dispersed in anhydrous ethanol, and lithium manganate was added to obtain a mixed dispersion solution by ultrasonic stirring; The solid material after drying the mixed dispersion is heated to 450°C to 550°C under a protective atmosphere to form the first coating layer.

7. The method for preparing the composite lithium manganese oxide cathode material as described in claim 3, characterized in that, Step S3 includes: The composite lithium manganese oxide cathode material is obtained by fusing lithium manganese oxide particles coated with the first coating layer and PVDF particles using a high-speed mechanical fusion method, followed by high-temperature sintering and cooling.

8. A pole piece characterized by, Includes the composite lithium manganese oxide cathode material as described in claim 1 or 2, or includes the composite lithium manganese oxide cathode material obtained by the preparation method of the composite lithium manganese oxide cathode material as described in any one of claims 3-7.

9. A battery, characterized by Including the electrode as described in claim 8.

10. An electrical device, comprising: Includes the battery as described in claim 9.

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