A high-energy-density multi-element positive electrode material, a preparation method thereof, a positive electrode sheet, a battery, and a battery pack

Abstract

This application provides a high-energy-density multi-element cathode material, its preparation method, cathode sheet, battery, and battery pack. The high-energy-density multi-element cathode material includes first material particles and second material particles; the first material particles include a core and a carbon coating layer covering at least a portion of the surface of the core; the core includes lithium manganese iron phosphate particles and lithium iron phosphate particles; the second material particles include lithium nickel cobalt manganese oxide particles; the particle size of the lithium manganese iron phosphate particles is smaller than the particle size of the lithium iron phosphate particles; the particle size of the first material particles is smaller than the particle size of the second material particles. This high-energy-density multi-element cathode material achieves a balanced optimization of compaction density, energy density, and safety.

Description

Technical Field

[0001] This application relates to the field of lithium-ion battery materials, and in particular to a high-energy-density multi-element cathode material and its preparation method, cathode sheet, battery, and battery pack. Background Technology

[0002] In the field of new energy batteries, lithium-ion batteries, as core energy storage devices, are widely used in electric vehicles, energy storage power stations, consumer electronics (such as smartphones and laptops), and aerospace. Among them, the cathode material, as a core component of lithium-ion batteries, directly affects the battery's energy density, cycle life, safety, and cost.

[0003] As electric vehicles increasingly demand higher driving range and faster charging speeds, and energy storage systems face increasingly stringent requirements for high energy density and long-cycle stability, cathode materials must simultaneously meet multiple needs, including high capacity, high compaction density (to improve volumetric energy density), low cost, and high safety. High compaction density helps improve the volumetric energy density of batteries, meeting the requirements for miniaturization and lightweighting; high capacity directly determines the mass energy density of batteries, affecting driving range and usage time; and high safety is a prerequisite for ensuring reliable battery operation under various operating conditions.

[0004] However, existing cathode material systems struggle to achieve a good balance across these three dimensions. For example, some high-capacity materials suffer from high cost and poor thermal stability due to their inherent properties; materials that prioritize high solid density often fall short in terms of capacity utilization or thermal stability; and materials with better safety may sacrifice energy density.

[0005] Therefore, developing a cathode material that can simultaneously achieve high real density, high capacity, high safety, and low cost has become a pressing technical challenge in this field. Summary of the Invention

[0006] This application provides a high-energy-density multi-element cathode material and its preparation method, cathode sheet, battery, and battery pack, which balance energy density, compaction performance, safety, and cost, while improving the process adaptability and performance stability when the material combination is used.

[0007] In a first aspect, embodiments of this application provide a high-energy-density multi-element cathode material, comprising first material particles and second material particles;

[0008] The first material particle includes a core and a carbon coating layer covering at least a portion of the surface of the core;

[0009] The core body includes lithium manganese iron phosphate particles and lithium iron phosphate particles;

[0010] The second material particles include lithium nickel cobalt manganese oxide particles;

[0011] The particle size of the lithium manganese iron phosphate particles is smaller than that of the lithium iron phosphate particles.

[0012] The particle size of the first material is smaller than that of the second material.

[0013] In one possible implementation, the particle size of the lithium manganese iron phosphate particles is 100nm-300nm;

[0014] And / or, the particle size of the lithium iron phosphate particles is 1μm-5μm;

[0015] And / or, the particle size of the lithium nickel cobalt manganese oxide particles is 8μm-30μm;

[0016] And / or, the thickness of the carbon coating layer is 1nm-3nm.

[0017] In one possible implementation, the lithium manganese iron phosphate particles account for 10%-50% of the mass fraction of the high energy density multi-element cathode material;

[0018] And / or, the lithium iron phosphate particles account for 10%-50% of the mass fraction of the high energy density multi-element cathode material;

[0019] And / or, the lithium cobalt manganese oxide particles account for 10%-50% of the mass fraction of the high energy density multi-element cathode material.

[0020] In one possible implementation, the compaction density of the high-energy-density multi-element cathode material is 2.7 g / cm³. 3 -3.7g / cm 3 .

[0021] Secondly, embodiments of this application provide a method for preparing the above-mentioned high energy density multi-element cathode material, comprising: grinding a first raw material mixture including a lithium manganese iron phosphate precursor and a lithium iron phosphate precursor, and then sintering a system including the grinding product and a carbon source to obtain the first material particles; wherein the particle size of the lithium manganese iron phosphate precursor is smaller than the particle size of the lithium iron phosphate precursor.

[0022] The first material particles are mixed with second material particles including lithium nickel cobalt manganese oxide particles to obtain the high energy density multi-element cathode material; wherein the particle size of the first material particles is smaller than the particle size of the second material particles.

[0023] In one possible implementation, the particle size of the lithium manganese iron phosphate precursor is 100nm-300nm;

[0024] And / or, the particle size of the lithium iron phosphate precursor is 1μm-4μm;

[0025] And / or, the mass ratio of the carbon source to the milled product is (0.05-0.15):1.

[0026] In one possible implementation, the grinding process is performed at a rotation speed of 1800 rpm to 3000 rpm.

[0027] And / or, the sintering temperature is 600℃-800℃, and the sintering time is 5h-12h.

[0028] Thirdly, embodiments of this application provide a positive electrode sheet, including the above-mentioned high energy density multi-element positive electrode material or the high energy density multi-element positive electrode material prepared by the above-mentioned preparation method.

[0029] Fourthly, embodiments of this application provide a battery including the aforementioned positive electrode sheet.

[0030] Fifthly, embodiments of this application provide a battery pack comprising at least two of the aforementioned batteries.

[0031] The high-energy-density multi-element cathode material, its preparation method, battery, and battery pack provided in this application embodiment, by setting a first material particle containing lithium manganese iron phosphate particles and lithium iron phosphate particles, and forming a carbon coating layer on at least part of its surface, while making the second material particle include lithium nickel cobalt manganese oxide particles, and controlling the particle size of the lithium manganese iron phosphate particles to be smaller than that of the lithium iron phosphate particles and the particle size of the first material particles to be smaller than that of the second material particles, can achieve synergistic coordination of different cathode materials in terms of composition, conductivity, and particle size distribution, thereby helping to balance the compaction density, energy density, safety, and cost of the cathode material, and improving the overall application effect and performance stability. Attached Figure Description

[0032] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0033] Figure 1 This is a SEM image of the lithium manganese iron phosphate precursor provided in Example 1 of this application;

[0034] Figure 2 This is a SEM image of the lithium iron phosphate precursor provided in Example 1 of this application;

[0035] Figure 3 This is a SEM image of the lithium nickel cobalt manganese oxide particles provided in Example 1 of this application;

[0036] Figure 4SEM image of the high energy density multi-element cathode material provided in Example 1 of this application Figure 1 ;

[0037] Figure 5 SEM image of the high energy density multi-element cathode material provided in Example 1 of this application Figure 2 .

[0038] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0039] Exemplary embodiments will be described in detail below. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0040] In existing technologies, cathode material optimization typically employs single-material particle size gradation or binary mixing of two cathode materials to improve powder packing and increase electrode compaction density. For example, lithium iron phosphate materials often combine large and small particles, utilizing interparticle gap filling to improve densification; lithium manganese iron phosphate materials also compensate for insufficient voltage plateau by refining particles; ternary materials are used to improve system energy density due to their high capacity. However, these approaches have significant limitations in practical applications: grading single or two materials makes it difficult to achieve large material size dispersion in order to balance various parameters such as capacity and compaction, thus significantly affecting the gradation effect and hindering the improvement of compaction density; while single-material gradation can improve compaction performance, it is difficult to overcome the limitations of intrinsic capacity and voltage plateau; binary mixing can balance performance to some extent, but often introduces new contradictions, such as high-capacity materials having higher costs and insufficient thermal stability, while low-cost materials have lower energy density, and significant differences in electronic conductivity, particle strength, and cycle decay behavior between different materials can easily lead to uneven stress within the electrode and increased interfacial impedance. It is evident that existing cathode materials cannot simultaneously meet the comprehensive requirements of high energy density, high compaction density, safety, and cost control.

[0041] The high energy density multi-element cathode material provided in this application combines the three materials LFP, LMFP and NCM through a three-level gradation (large LFP particles, small LMFP particles, and even larger NCM particles), and combines stepwise preparation and mixed sintering processes to transform the differences in particle size, electrochemical characteristics and preparation conditions of different materials into complementary performance, thereby achieving a multi-dimensional balance between energy density, compaction density, cost and safety of the cathode material.

[0042] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0043] The high energy density multi-element cathode material provided in this application includes a first material particle and a second material particle; the first material particle includes a core and a carbon coating layer covering at least a portion of the surface of the core; the core includes lithium manganese iron phosphate particles and lithium iron phosphate particles; the second material particle includes lithium nickel cobalt manganese oxide particles; the particle size of the lithium manganese iron phosphate particles is smaller than the particle size of the lithium iron phosphate particles; the particle size of the first material particle is smaller than the particle size of the second material particle.

[0044] In the embodiments of this application, high-energy-density multi-element cathode materials can be used in lithium-ion battery cathode active material systems, and are particularly suitable for power batteries, energy storage batteries and high-performance consumer electronics batteries that have comprehensive requirements for volumetric energy density, compaction density, cycle stability and safety.

[0045] The first material particle comprises a composite core of lithium iron phosphate particles and lithium manganese iron phosphate particles, with a carbon coating layer forming at least partially covering its outer surface. In the composite core structure, the combination of lithium manganese iron phosphate particles and lithium iron phosphate particles forms a synergistic effect of voltage plateau compensation and structural support, while the carbon coating layer constructs a continuous conductive network on the core surface, alleviating interfacial polarization and improving electron transport efficiency, thereby constituting a composite particle with both conductivity and structural stability. The second material particle includes lithium nickel cobalt manganese oxide particles, which can exist as independent secondary particles and are mixed and graded with the first material particle.

[0046] The smaller particle size of lithium manganese iron phosphate (LFP) particles compared to lithium iron phosphate (LFP) particles is a crucial structural constraint for this primary material. By forming a particle size distribution of "large LFP skeleton + small LFP filler," finer LFP particles can be distributed within the gaps between larger LFP particles, reducing the volume of ineffective pores in the powder packing and increasing the number of particle contact points and densification. This process achieves the goal of improving the packing structure at the particle scale, making it easier for the primary material particles to achieve higher compaction density during subsequent tableting. Furthermore, the relatively shorter lithium-ion diffusion path of small-diameter LFP particles also positively impacts lithium-ion insertion / extraction kinetics at higher rates. Additionally, the high voltage plateau of manganese in LFP is beneficial for increasing the energy density of the LFP material, enabling the cathode material to achieve higher charge.

[0047] Particle size differences can be achieved by controlling the ball milling time, ball-to-material ratio, precursor nucleation rate, sintering temperature, and holding time during the preparation process. For example, strong dispersion and confined growth conditions are used for lithium manganese iron phosphate to suppress abnormal grain growth, while relatively mild particle growth conditions are used for lithium iron phosphate to form a stable supporting framework.

[0048] The second material particles include lithium nickel cobalt manganese oxide particles, preferably layered lithium nickel cobalt manganese oxide materials with high crystallinity and relatively regular secondary particle morphology.

[0049] To further improve the structural stability and surface resistance to side reactions under high voltage conditions, lithium nickel cobalt manganese oxide (NCM) particles can be coated with alumina, silica, phosphate, or modified with elemental doping. For example, alumina coating can suppress lattice distortion of NCM particles, silica coating can reduce electrolyte side reactions, and elemental doping (such as Mg and Al) can optimize their surface chemical stability. Since lithium nickel cobalt manganese oxide has a significant advantage in capacity contribution, introducing it as a secondary material particle into the system can supplement the capacity limit of the phosphate system, thereby improving the overall mass energy density and volumetric energy density of the cathode material. Furthermore, its presence as larger particle size facilitates the formation of a skeletal support structure in the powder, reducing the increased specific surface area and enhanced side reactions caused by an excessively high proportion of fine particles.

[0050] The particle size of the first material is smaller than that of the second material. This limitation creates a second layer of gradation at the particle group scale, in addition to the particle size distribution within the core of the high-energy-density multi-element cathode material. Through this size configuration, the smaller-diameter first material particles can be embedded in the gaps between the larger-diameter second material particles, while the larger-diameter second material particles form the main supporting framework of the overall powder, thus forming a multi-level gradation structure of "large particle skeleton—small particle filling—even smaller particle micro-filling." This process achieves multi-scale space filling, reduces porosity through optimized particle size distribution, improves the uniformity of stress on the cathode sheet during rolling, and reduces the risk of localized stress concentration and particle breakage. Simultaneously, because the first material particles contain a carbon coating layer, they can provide electronic conduction connections in localized areas when distributed between the second material particles, establishing a more continuous conductive network between lithium nickel cobalt manganese oxide particles and between them and phosphate particles, thereby reducing the electronic transport impedance of the composite system.

[0051] As can be seen, the high energy density multi-element cathode material provided in this application embodiment can improve compaction density and overall energy density without significantly sacrificing safety and process adaptability compared to single-material gradation or conventional binary mixed materials.

[0052] Because there is a clear particle size hierarchy between the first and second material particles, the porosity of the electrode decreases and the volume utilization rate increases after rolling, which is beneficial to improving the volumetric energy density. The introduction of smaller lithium manganese iron phosphate particles into the core, along with the carbon coating layer, can improve the synergistic transport of electrons and ions between particles, thereby reducing polarization during charge and discharge. Since lithium iron phosphate and lithium manganese iron phosphate can be prepared under similar reducing atmosphere conditions and first form the first material particles, and then be mixed with lithium nickel cobalt manganese oxide particles that are usually prepared separately in an oxygen atmosphere, the overall process is easier to control than the complex integration of multiple materials after complete dispersion treatment. It is also more conducive to reducing the introduction of impurities and damage to the particle structure. It should be understood that the above-mentioned material types, particle size ranges, mass ratios, carbon layer thicknesses, coating processes, and surface modification methods can all be equivalently replaced or adapted without departing from the core concept of this application. For example, different carbon sources, different sieving methods, different granulation processes, or different surface coating systems can be used to meet the comprehensive requirements of different battery systems for high energy density, high compaction density, cycle stability, and safety. The above examples are merely illustrative and not limiting.

[0053] In some specific implementations, the particle size of lithium manganese iron phosphate particles is 100nm-300nm, which can be obtained by enhanced crushing, confined growth, spray granulation or graded screening, so that they can preferentially fill the pores between larger particles as fine particles, thereby improving the overall packing density.

[0054] For example, the particle size of lithium manganese iron phosphate particles can be a range of 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, or any combination thereof.

[0055] In some specific implementations, the lithium iron phosphate particles have a particle size of 1μm-5μm. By adjusting the ball milling time, sintering temperature, holding time, and particle size distribution, suitable micron-sized particles can be formed, which can both serve as the main stacking framework and provide embedding space for nano-sized particles.

[0056] For example, the particle size of lithium iron phosphate particles can be a range of 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, or any combination thereof.

[0057] In some specific embodiments, the first material particles can be a plurality of composite particles composed of lithium iron phosphate and lithium manganese iron phosphate, wherein the D50 particle size of the composite particles can be controlled in the range of 0.5μm-5μm, for example, 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, 5μm or any combination thereof.

[0058] In some specific implementations, the particle size of lithium nickel cobalt manganese oxide particles is 8μm-30um, which is more conducive to constructing a larger secondary particle skeleton, improving particle size distribution and increasing compaction density.

[0059] For example, the particle size of lithium nickel cobalt manganese oxide particles can be a range of 8 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm or any combination thereof.

[0060] The synergistic effect of different particle sizes mentioned above is essentially based on the principle of multi-level particle filling and skeleton support, which reduces the porosity and increases the contact points of the powder during roll forming, thereby reducing internal resistance and improving the densification level of the electrode.

[0061] In some specific implementations, the thickness of the carbon coating layer is 1nm-3nm.

[0062] A carbon coating layer with a thickness of 1nm-3nm can construct a continuous or semi-continuous conductive network on the core surface, improving electron transport efficiency. Simultaneously, due to its extremely thin thickness, it minimizes obstruction to the lithium-ion diffusion path. The presence of the carbon coating layer improves interparticle electrical contact and alleviates interfacial polarization during electrochemical cycling, thus balancing rate performance and cycle stability. By synergistically optimizing the particle size distribution and carbon layer thickness, the packing density of the multi-element cathode material is enhanced, while conductivity and structural stability are improved, thereby achieving a balance between high energy density and high compaction density.

[0063] For example, the thickness of the carbon coating can be a range of 1 nm, 2 nm, 3 nm, or any combination thereof.

[0064] In some specific embodiments, lithium manganese iron phosphate particles account for 10%-50% of the mass fraction of the high energy density multi-element cathode material.

[0065] In some specific embodiments, lithium iron phosphate particles account for 10%-50% of the mass fraction of the high energy density multi-element cathode material.

[0066] In some specific embodiments, lithium nickel cobalt manganese oxide particles account for 10%-50% of the mass fraction of the high energy density multi-element cathode material.

[0067] In this embodiment, by proportioning lithium manganese iron phosphate particles, lithium iron phosphate particles, and lithium nickel cobalt manganese oxide particles within the aforementioned mass fraction range, the three components complement and synergize within the overall system. Lithium iron phosphate particles provide a stable olivine structural framework and lower cost; lithium manganese iron phosphate particles raise the voltage platform and supplement energy density through the manganese component; and lithium nickel cobalt manganese oxide particles further improve specific capacity and rate response. This establishes a balance between capacity, compaction, and safety among the different particles. By controlling each component within the range of 10%-50%, both insufficient functional contribution due to excessively low levels of any component and structural imbalance, increased interfacial impedance, or decreased thermal stability due to excessively high levels of any component are avoided, resulting in more uniform particle packing and more stable electrode forming characteristics.

[0068] Specifically, when the proportion of lithium manganese iron phosphate particles is between 10% and 50%, it can be used as a key component to improve the voltage platform and participate in the mixing process. Together with lithium iron phosphate particles, it forms a core with a supporting function, thereby improving the overall energy output while maintaining processing stability.

[0069] When the proportion of lithium iron phosphate particles is between 10% and 50%, it can form a relatively stable bearing network during the compaction process, improve the contact state between particles, and reduce costs.

[0070] When the proportion of lithium cobalt manganese oxide particles is between 10% and 50%, its high capacity characteristics can effectively compensate for the insufficient specific capacity of the phosphate system, and the volumetric energy density of the system can be improved by introducing large particles.

[0071] Through the above-mentioned proportioning design, the three types of particles respectively play the roles of structural support, plateau compensation and capacity enhancement during charging and discharging, so that the material can still maintain low polarization, good cycle stability and safety characteristics under high pressure density conditions.

[0072] This process achieves synergistic optimization of the particle size distribution, material properties, and electrochemical functions of high-energy-density multi-component cathode materials, thereby improving the energy storage capacity per unit volume and per unit mass without significantly sacrificing safety. Because each component is confined within a reasonable mass fraction window, the material is more likely to form continuous conductive and ion transport channels during mixing, granulation, compaction, and cycling, thus ensuring electrode densification, rate performance, and long-term cycling consistency.

[0073] For example, the mass fraction of lithium manganese iron phosphate particles in the high energy density multi-element cathode material can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or any combination thereof.

[0074] For example, the mass fraction of lithium iron phosphate particles in the high energy density multi-element cathode material can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or any combination thereof.

[0075] For example, the mass fraction of lithium nickel cobalt manganese oxide particles in the high energy density multi-element cathode material can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or any combination thereof.

[0076] In some specific implementations, the compaction density of the high-energy-density multi-element cathode material is 2.7 g / cm³. 3 -3.7g / cm 3 .

[0077] The powder packing density of this high-energy-density multi-element cathode material was controlled at 2.7 g / cm³. 3 -3.7g / cm 3 This process effectively compresses the voids between particles and forms a more stable contact network, reflecting the excellent packing state resulting from the combined effects of particle size distribution, component ratio, and surface carbon layer. Simultaneously, it facilitates a balance between high energy density and good processability, enabling the material to form an electrode structure with low porosity and high filler content after rolling. This improves the volumetric energy density of the battery system and reduces internal contact resistance, thereby contributing to the maintenance of rate performance and cycle stability.

[0078] For example, the compaction density of a high-energy-density multi-element cathode material can be 2.7 g / cm³. 3 2.8g / cm 3 2.9g / cm 3 3.0g / cm 3 3.1g / cm 3 3.2g / cm 3 3.3g / cm3 3.4g / cm 3 3.5g / cm 3 3.6g / cm 3 3.7g / cm 3 Or a range consisting of any two of them.

[0079] The high-energy-density multi-element cathode material provided in this application embodiment firstly comprises lithium iron phosphate particles and lithium manganese iron phosphate particles together forming a first material particle core, wherein the larger-diameter lithium iron phosphate particles form a relatively stable support unit, and the smaller-diameter lithium manganese iron phosphate particles fill the gaps and increase the working voltage; secondly, a carbon coating layer is provided on the outside of the core, which compensates for the relatively insufficient electronic conductivity of the phosphate material by means of a surface conductive network, thereby reducing the transmission impedance at the contact interface between different particles; thirdly, the overall size of the first material particles is smaller than that of the second material particles, enabling them to fill the gaps between the secondary nickel cobalt manganese oxide particles, further improving the system stacking efficiency. During electrode fabrication, this structure enables the powder to form denser and more uniform conductive / ion transport channels after coating, drying, and rolling. This increases the loading of active material within a limited electrode thickness and reduces electrode porosity fluctuations and localized polarization. During electrochemical cycling, lithium nickel cobalt manganese oxide provides higher capacity output, lithium manganese iron phosphate improves the average voltage plateau, lithium iron phosphate maintains structural stability and safety margins, and the carbon coating stabilizes the particle interface and improves electron accessibility. This results in a better balance between energy density, rate performance, cycle life, and thermal stability in the composite system.

[0080] This application also provides a method for preparing the above-mentioned high energy density multi-element cathode material, the method comprising:

[0081] After grinding a first raw material mixture including lithium manganese iron phosphate precursor and lithium iron phosphate precursor, the system including the grinding product and carbon source is sintered to obtain first material particles; wherein the particle size of the lithium manganese iron phosphate precursor is smaller than the particle size of the lithium iron phosphate precursor.

[0082] A first material particle is mixed with a second material particle, including lithium nickel cobalt manganese oxide particles, to obtain a high-energy-density multi-element cathode material; wherein the particle size of the first material particle is smaller than that of the second material particle.

[0083] In some embodiments, the lithium iron phosphate precursor can be obtained by mixing, grinding, and sintering an iron source, a lithium source, a phosphorus source, and a carbon source. The iron source can be ferrous sulfate, ferrous oxalate, or iron phosphate; the lithium source can be lithium carbonate, lithium hydroxide, or lithium phosphate; and the phosphorus source can be ammonium dihydrogen phosphate, phosphoric acid, or phosphate. The lithium manganese iron phosphate precursor is prepared by further introducing a manganese source, such as manganese carbonate, manganese tetroxide, or manganese sulfate, into the raw materials for preparing the lithium iron phosphate precursor, and then mixing, drying, pre-calcining, and high-temperature sintering to form the target material.

[0084] In one exemplary embodiment, the two precursors can be uniformly mixed in a preset ratio and then sintered in a reducing atmosphere of nitrogen / hydrogen mixture, so that the two phosphate particles establish a closer spatial distribution relationship during the formation process. The setting of the reducing atmosphere helps to maintain the appropriate valence state of iron and promotes the formation of conductive carbon, thereby making the first material particles more compatible in the preparation process and avoiding agglomeration, contamination or particle structure damage during multiple transfers and post-mixing processes after separate preparation.

[0085] In one possible embodiment, the first raw material mixture can be pre-dispersed uniformly by dry or wet mixing so that the smaller-sized lithium manganese iron phosphate precursor preferentially fills the gaps between the lithium iron phosphate precursor particles, and is further refined and homogenized in the subsequent grinding process.

[0086] The grinding process can be carried out using at least one of ball milling, sand milling or air jet milling; the grinding time, speed and media ratio can be adjusted according to the target particle size so that the mixed system forms an intermediate product with a more reasonable particle size distribution.

[0087] In some embodiments, the grinding speed is 1800 rpm to 3000 rpm, and the grinding time can be 0.5 h.

[0088] In the above preparation process, the particle size of the lithium manganese iron phosphate precursor is smaller than that of the lithium iron phosphate precursor, which is conducive to the formation of differentiated stacking and local filling structure during the mixing and grinding stages. This allows the core obtained after subsequent sintering to have both the reactivity of finer particles and the structural support of coarser particles.

[0089] When a system comprising grinding products and a carbon source is sintered, the carbon source may include glucose, sucrose, starch, pitch, polyvinyl alcohol, polyacrylonitrile, or a combination thereof. The amount of carbon source added can form a carbon coating layer with a thickness of 1 nm to 3 nm after sintering, thereby constructing a continuous conductive network on the surface of the core and suppressing particle growth during the sintering process. It can also reduce the interfacial resistance and buffer the micro-strain of volume, thereby suppressing particle pulverization during cycling.

[0090] In some embodiments, the sintering process can be carried out in a segmented heating manner under a protective atmosphere or a weak reducing atmosphere, preferably controlled within a temperature range suitable for the formation of the phosphate phase and lattice reconstruction, so as to promote the full conversion of the lithium manganese iron phosphate precursor and the lithium iron phosphate precursor under solid-state conditions and form a stable core structure, thereby obtaining the first material particles.

[0091] In some embodiments, a lithium nickel cobalt manganese oxide precursor can be prepared first by co-precipitation, and then mixed with a lithium source and sintered in an oxygen-containing atmosphere to obtain lithium nickel cobalt manganese oxide particles contained in the second material particles, so as to ensure the integrity of the layered crystal structure and maintain a high reversible capacity.

[0092] Subsequently, the first material particles are mixed with the second material particles, which have a larger particle size, using low-shear mixing or graded mixing. When mixing the first and second material particles, the particle size of the first material particles is smaller than that of the second material particles. Preferably, the first material particles are in the micrometer or submicrometer range, while the second material particles maintain a larger secondary particle morphology. This allows for the formation of a "fine particles filling gaps, large particles supporting the load" structure after mixing, preventing excessive breakage of the first material particles and ensuring a uniform spatial distribution of both types of particles. The mixing process can employ tumbling mixing, conical mixing, or low-speed stirring, with the mixing time determined by ensuring no significant agglomeration and without damaging the particle morphology.

[0093] The preparation method provided in this embodiment involves first mixing and grinding a smaller-particle-size lithium manganese iron phosphate precursor with a larger-particle-size lithium iron phosphate precursor. This allows the two types of phosphate components to form a composite precursor with higher uniformity before heat treatment. Then, a thin layer of carbon is formed on the surface of the core by sintering with a carbon source, thereby establishing a conductive pathway at the microscopic level and limiting abnormal grain growth. Simultaneously, the hierarchical design, where the particle size of the first material is smaller than that of the second material, allows small particles to fill the pores between large particles, improving packing density and reducing electrode porosity. Since lithium manganese iron phosphate and lithium iron phosphate have similar crystal chemical characteristics, they can form a stable phosphate core during sintering, while lithium nickel cobalt manganese oxide particles provide a higher voltage plateau and capacity contribution. The combination of these three components achieves a balance between high energy density and good safety.

[0094] In some specific implementations, the particle size of the lithium manganese iron phosphate precursor is 100nm-300nm.

[0095] In some specific implementations, the particle size of the lithium iron phosphate precursor is 1μm-4μm.

[0096] By controlling the particle size of the lithium manganese iron phosphate precursor to 100nm-300nm and the particle size of the lithium iron phosphate precursor to 1μm-4μm, while taking into account specific surface area, mixing uniformity and sintering activity, it is beneficial to control the particle size of the lithium manganese iron phosphate particles to 100nm-300nm and the particle size of the lithium iron phosphate particles to 1μm-4μm in the final first material particles.

[0097] It is understandable that the particle size of the lithium manganese iron phosphate precursor and the lithium iron phosphate precursor will change during the sintering process. However, the inventors have found through experiments that the difference between the particle size of the two precursors and the particle size of the lithium manganese iron phosphate particles and lithium iron phosphate particles formed in the first material particles before and after sintering is negligible.

[0098] In some specific implementations, the mass ratio of carbon source to grinding product is (0.05-0.15):1.

[0099] Since carbon materials themselves do not possess electrochemical activity, and the carbon coating layer increases the specific surface area of ​​the material, by controlling the mass ratio of carbon source to grinding product to (0.05-0.15):1, it is ensured that the carbon source preferentially forms a continuous and extremely thin coating layer (1nm-3nm) on the particle surface in situ during heat treatment. This can better guarantee the specific capacity and energy density of the obtained high-energy-density multi-element cathode material. It is generally advisable to form a continuous and thin coating layer to avoid the increase in impedance caused by an excessively thick carbon layer, and to balance its specific surface area and processability, thereby improving the overall performance of the material.

[0100] For example, the mass ratio of carbon source to grinding product can be 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1, 0.10:1, 0.11:1, 0.12:1, 0.13:1, 0.14:1, 0.15:1 or any combination thereof.

[0101] In some specific implementations, the grinding speed is 1800 rpm to 3000 rpm.

[0102] The grinding process can be carried out by ball milling, sand milling or planetary milling. The grinding speed can be set according to the difference in raw material particle size, mixing uniformity and crystal integrity. It is preferred to control it in the medium and high speed range so that the lithium manganese iron phosphate precursor and the larger lithium iron phosphate precursor can fully depolymerize and come into uniform contact in a short time to form a grinding product with a more reasonable particle size distribution.

[0103] For example, the grinding speed can be a range of 1800 rpm, 1900 rpm, 200 rpm, 2100 rpm, 2200 rpm, 2300 rpm, 2400 rpm, 2500 rpm, 2600 rpm, 2700 rpm, 2800 rpm, 2900 rpm, 3000 rpm, or any combination thereof.

[0104] The system, which includes the grinding product and the carbon source, is then sintered under an inert atmosphere, a reducing atmosphere, or a combination thereof. The sintering temperature and holding time can be determined according to the degree of crystallization of the precursor and the carbonization requirements, so that the carbon source is transformed into a coating layer in situ during heat treatment, and promotes the formation of a stable composite structure between lithium manganese iron phosphate and lithium iron phosphate core, thereby obtaining the first material particles that match the second material particles.

[0105] In some specific implementations, the sintering temperature is 600℃-800℃ and the sintering time is 5h-12h.

[0106] For example, the sintering temperature can be a range of 600°C, 650°C, 700°C, 750°C, 800°C or any combination thereof; the sintering time can be a range of 5h, 7h, 9h, 11h, 12h or any combination thereof.

[0107] The preparation method provided in this application, through the control of particle size and ratio, utilizes the high dispersibility of the lithium iron phosphate precursor to improve the uniformity of mixing, and leverages the larger particle skeleton of the lithium iron phosphate precursor to maintain structural support, enabling the ground product to form a core with both fine particle filling effect and crystal integrity during sintering. When the mass ratio of carbon source to ground product is within a reasonable range, carbon can preferentially form a continuous and extremely thin coating layer on the particle surface during heat treatment, reducing electron transport impedance and avoiding excessive carbon content that weakens the material's volumetric energy density. This process achieves the synergistic effect of precursor refinement, mixing homogenization, and sintering densification, thereby giving the first material particles a more stable conductive path and a more suitable particle size distribution. This ensures the compaction density, rate response, and cycle stability after compounding with lithium nickel cobalt manganese oxide particles, and reduces structural defects caused by particle size differences and interface mismatches in the multi-material system. This makes the multi-element cathode material more suitable for applications such as new energy vehicle power batteries, energy storage power stations, and high-performance consumer electronics batteries.

[0108] This application also provides a cathode material, including the above-mentioned high energy density multi-element cathode material or the high energy density multi-element cathode material prepared by the above-mentioned preparation method.

[0109] When the aforementioned cathode uses high-energy-density multi-element cathode material as the active material, the particle size difference and material properties of the first and second material particles can be introduced into the electrode structure. This makes it easier for the smaller-sized first material particles to fill the gaps between the larger-sized second material particles, improving the packing density and compaction of the electrode. The lithium manganese iron phosphate particles and lithium iron phosphate particles in the core complement each other in terms of capacity and structural stability, while the carbon coating layer helps improve particle conductivity and interfacial transport performance, thereby reducing the internal resistance of the electrode and improving rate performance. At the same time, lithium nickel cobalt manganese oxide particles provide a high capacity contribution, enabling the cathode to achieve higher energy density while ensuring structural stability and safety. Therefore, it can better meet the comprehensive requirements of high compaction, high capacity and long cycle life of power batteries, energy storage batteries and high-performance consumer electronics batteries.

[0110] The positive electrode provided in this embodiment can perform the method provided in the above method embodiment. Its implementation principle and technical effect are similar, and will not be described in detail here.

[0111] This application also provides a battery including the above-described positive electrode.

[0112] This application also provides a battery pack comprising at least two of the aforementioned batteries.

[0113] The technical solution of this application will be further described below using specific embodiments.

[0114] Example 1

[0115] A high-energy-density multi-element cathode material includes first material particles and second material particles. The first material particles include a core and a carbon coating layer on the surface of the core. The core includes lithium manganese iron phosphate particles (particle size of 200 nm) and lithium iron phosphate particles (particle size of 2 μm). The second material particles are lithium nickel cobalt manganese oxide particles (particle size of 15 μm). The mass fraction of lithium manganese iron phosphate particles is 40%, the mass fraction of lithium iron phosphate particles is 30%, and the mass fraction of lithium nickel cobalt manganese oxide particles is 30%.

[0116] Its preparation method includes the following steps:

[0117] Preparation of lithium manganese iron phosphate precursor: 9.85g lithium carbonate, 29.22g ammonium dihydrogen phosphate, 10.14g iron oxide, 14.60g manganese carbonate, and 3.2g glucose were added to a ball mill along with 50ml deionized water and mixed and ground for 2 hours. The ball milled slurry was then spray-dried to obtain a dried lithium manganese iron phosphate precursor with a D50 particle size of 210nm.

[0118] Preparation of lithium iron phosphate precursor: 7.37g lithium carbonate, 21.86g ammonium dihydrogen phosphate, 15.17g iron oxide and 2.22g glucose were added to 40ml deionized water and mixed and ground in a ball mill for 2 hours; then the ball-milled slurry was dried to obtain a dried lithium iron phosphate precursor with a D50 particle size of 2.05μm;

[0119] Preparation of the first material particles: The lithium manganese iron phosphate precursor and the lithium iron phosphate precursor were mixed at a mass ratio of 1:1 and sintered under a nitrogen atmosphere at a sintering temperature of 760℃ for 10h. After cooling, the first material particles were obtained with a D50 particle size of 2.5μm and a carbon coating thickness of 2nm.

[0120] Preparation of lithium nickel cobalt manganese oxide particles: 12.05g lithium carbonate, 11.60g nickel oxide, 4.99g cobalt oxide and 10.72g manganese carbonate were mixed and ground evenly, and then calcined at 780℃ to obtain lithium nickel cobalt manganese oxide particles with a particle size of 15μm.

[0121] The first material particles were mixed with lithium nickel cobalt manganese oxide particles at a mass ratio of 7:3 to obtain a high-energy-density multi-element cathode material.

[0122] Example 2

[0123] A high-energy-density multi-element cathode material has a structure that is basically the same as that in Example 1, except that the particle size of lithium manganese iron phosphate particles is 100 nm, the particle size of lithium iron phosphate particles is 1 μm, the carbon coating layer thickness on the surface of the first material particles is 1 nm, and the particle size of lithium nickel cobalt manganese oxide particles is 10 μm.

[0124] The preparation method is the same as that in Example 1.

[0125] Example 3

[0126] A high-energy-density multi-element cathode material has a structure that is basically the same as that in Example 2, except that the particle size of the lithium manganese iron phosphate particles is 80 nm.

[0127] The preparation method is the same as that in Example 2.

[0128] Example 4

[0129] A high-energy-density multi-element cathode material has a structure that is basically the same as that in Example 2, except that the lithium iron phosphate particles have a particle size of 0.8 μm.

[0130] The preparation method is the same as that in Example 2.

[0131] Example 5

[0132] A high-energy-density multi-element cathode material has a structure that is basically the same as that in Example 2, except that the lithium nickel cobalt manganese oxide particles have a particle size of 7 μm.

[0133] The preparation method is the same as that in Example 2.

[0134] Example 6

[0135] A high-energy-density multi-element cathode material has a structure that is basically the same as that in Example 1, except that the particle size of lithium manganese iron phosphate particles is 300 nm, the particle size of lithium iron phosphate particles is 4 μm, the carbon coating layer thickness on the surface of the first material particles is 3 nm, and the particle size of lithium nickel cobalt manganese oxide particles is 30 μm.

[0136] The preparation method is the same as that in Example 1.

[0137] Example 7

[0138] A high-energy-density multi-element cathode material has a structure that is basically the same as that in Example 6, except that the particle size of the lithium manganese iron phosphate particles is 310 nm.

[0139] The preparation method is the same as that in Example 6.

[0140] Example 8

[0141] A high-energy-density multi-element cathode material has a structure that is basically the same as that in Example 6, except that the lithium iron phosphate particles have a particle size of 4.5 μm.

[0142] The preparation method is the same as that in Example 6.

[0143] Example 9

[0144] A high-energy-density multi-element cathode material has a structure that is basically the same as that in Example 6, except that the particle size of the lithium nickel cobalt manganese oxide particles is 32 μm.

[0145] The preparation method is the same as that in Example 6.

[0146] Example 10

[0147] A high-energy-density multi-element cathode material has a structure that is basically the same as that in Example 1, except that the mass fraction of lithium nickel cobalt manganese oxide particles is 10%, the mass fraction of lithium iron phosphate particles is 40%, and the mass fraction of lithium nickel cobalt manganese oxide particles is 50%.

[0148] The preparation method is the same as that in Example 1.

[0149] Example 11

[0150] A high-energy-density multi-element cathode material has a structure that is basically the same as that of Example 10, except that the mass fraction of lithium nickel cobalt manganese oxide particles is 8%, the mass fraction of lithium iron phosphate particles is 40%, and the mass fraction of lithium nickel cobalt manganese oxide particles is 52%.

[0151] The preparation method is the same as that in Example 10.

[0152] Example 12

[0153] A high-energy-density multi-element cathode material has a structure that is basically the same as that in Example 1, except that the mass fraction of lithium nickel cobalt manganese oxide particles is 50%, the mass fraction of lithium iron phosphate particles is 10%, and the mass fraction of lithium nickel cobalt manganese oxide particles is 40%.

[0154] The preparation method is the same as that in Example 1.

[0155] Example 13

[0156] A high-energy-density multi-element cathode material has a structure that is basically the same as that in Example 12, except that the mass fraction of lithium nickel cobalt manganese oxide particles is 55%, the mass fraction of lithium iron phosphate particles is 5%, and the mass fraction of lithium nickel cobalt manganese oxide particles is 40%.

[0157] Its preparation method is the same as that in Example 12.

[0158] Example 14

[0159] A high-energy-density multi-element cathode material has a structure that is basically the same as that of Example 10, except that the mass fraction of lithium nickel cobalt manganese oxide particles is 10%, the mass fraction of lithium iron phosphate particles is 35%, and the mass fraction of lithium nickel cobalt manganese oxide particles is 55%.

[0160] The preparation method is the same as that in Example 10.

[0161] Example 15

[0162] A high-energy-density multi-element cathode material has a structure that is basically the same as that of Example 10, except that the mass fraction of lithium nickel cobalt manganese oxide particles is 50%, the mass fraction of lithium iron phosphate particles is 40%, and the mass fraction of lithium nickel cobalt manganese oxide particles is 10%.

[0163] The preparation method is the same as that in Example 10.

[0164] Example 16

[0165] A high-energy-density multi-element cathode material has a structure that is basically the same as that in Example 15, except that the mass fraction of lithium nickel cobalt manganese oxide particles is 50%, the mass fraction of lithium iron phosphate particles is 42%, and the mass fraction of lithium nickel cobalt manganese oxide particles is 8%.

[0166] The preparation method is the same as that in Example 15.

[0167] Comparative Example 1

[0168] A multi-element cathode material, whose structure is basically the same as that of Example 1, except that the particle size of the lithium manganese iron phosphate particles is equal to that of the lithium iron phosphate particles.

[0169] Comparative Example 2

[0170] A multi-element cathode material, the structure of which is basically the same as that of Example 1, except that the particle size of the first material particle is equal to the particle size of the second material particle.

[0171] Comparative Example 3

[0172] A multi-element cathode material, the structure of which is basically the same as that of Example 1, except that it does not include lithium nickel cobalt manganese oxide particles.

[0173] Comparative Example 4

[0174] A multi-element cathode material, whose structure is basically the same as that of Example 1, except that it does not include lithium manganese iron phosphate particles.

[0175] Comparative Example 5

[0176] A multi-element cathode material, whose structure is basically the same as that of Example 1, except that it does not include lithium iron phosphate particles.

[0177] The relevant physical properties of the materials obtained in the above embodiments and comparative examples are shown in Table 1:

[0178] Table 1

[0179]

[0180]

[0181] like Figure 1 , Figure 2 and Figure 3 As shown, lithium manganese iron phosphate precursor, lithium iron phosphate precursor, and lithium nickel cobalt manganese oxide material with the target particle size were successfully prepared according to the preparation method provided in Example 1 of this application. Figure 4 It can be seen that in the high energy density multi-element cathode material prepared in Example 1, a good particle size distribution and mixing were achieved among the LMFP formed by sintering the lithium manganese iron phosphate precursor, the LFP formed by sintering the lithium iron phosphate precursor, and the NCM particles. LMFP and LFP particles were attached to the surface of the larger NCM particles. Figure 5 As can be seen, smaller LMFP particles can also adhere to the surface of larger LFP particles.

[0182] The materials obtained from the above embodiments and comparative examples were used to prepare coin cells according to the following steps:

[0183] Positive electrode preparation: 1.5g of material was mixed with conductive carbon black and PVDF at a mass ratio of 8:1:1 and dispersed in 4ml of NMP. After vacuum degassing, a positive electrode slurry was obtained. The obtained positive electrode fragrance was uniformly coated on the surface of the positive electrode current collector aluminum foil with a wet film thickness of 50μm. The foil was dried in a 100℃ oven and compacted using a roller press. Then, it was slit or punched into round pieces with a diameter of 12mm for later use.

[0184] Coin cell fabrication: In a glove box filled with argon and where the oxygen content of water is below 0.1 ppm, the prepared positive electrode is used as the working electrode. Electrolyte (1 mol / L LiPF6 in EC:DEC, where EC:DEC = 1:1) is dropped onto the active layer surface of the positive electrode, and then covered with a polypropylene (PP) microporous membrane (19 mm in diameter). Electrolyte is then dropped onto the membrane again to ensure it is fully wetted. A lithium metal sheet (15.6 mm in diameter, 0.45 mm thick), a gasket, and a spring are then placed in sequence and assembled. Pressure is then applied to seal the assembly, forming a coin cell.

[0185] The following performance tests were performed on the obtained button cells:

[0186] Specific capacity: First, charge the coin cell at a constant current of 0.1C to a voltage of 4.35V, then charge it at a constant voltage of 4.35V to a current of 0.05C, and record the initial charge capacity; then let it stand for 5 minutes, and discharge it at a constant current of 0.1C to a voltage of 2.5V, and record the initial discharge capacity; the specific capacity is the initial discharge capacity / (mass of positive electrode - mass of current collector).

[0187] Volumetric density: The product of bulk density and compacted density is the volumetric density.

[0188] Cycle count: Cycle according to the test steps of the first charge capacity and the first discharge capacity. One charge and one discharge constitute one cycle. Record the number of cycles when the coulombic efficiency is less than 80%.

[0189] The test results are detailed in Table 2:

[0190] Table 2

[0191]

[0192]

[0193] As can be seen from the data in Tables 1 and 2, the high-energy multi-element cathode material provided in this application has a high compaction density. When used as a cathode material for batteries, it can produce batteries with excellent energy density and cycle performance.

[0194] Compared to Examples 3-5, Example 2 exhibits a higher compaction density. This demonstrates that when the particle size of any material in the high-energy multi-element cathode material is smaller than the lower limit of the corresponding preferred particle size range, the compaction density of the resulting high-energy multi-element cathode material decreases. Consequently, the volumetric capacity density of the battery prepared using this high-energy multi-element cathode material decreases.

[0195] As can be seen from the results of Examples 10-16, reducing the content of any one of the three components to below 10% while increasing the content of another component to above 50% affects the volumetric energy density of the resulting high-energy multi-component cathode material, leading to a decrease in the cycle performance of the prepared battery. Therefore, when the contents of LFMP, LFP, and NCM in the high-energy multi-component cathode material are all between 10% and 50%, a battery with better cycle performance can be obtained.

[0196] Compared with Comparative Examples 1-2, the high-energy multi-component cathode material obtained in Example 1 has a higher compaction density and a higher energy density of the battery. This indicates that when the particle sizes of the three components in the high-energy multi-component cathode material reach the gradation relationship required by this application, a battery with excellent energy density and cycle performance can be obtained.

[0197] Compared with Comparative Examples 3-5, the high-energy multi-element cathode material obtained in Example 1 has a higher compaction density, and the battery has higher energy density and cycle performance. This shows that the battery prepared using the high-energy multi-element cathode material provided in this application can obtain a battery with excellent energy density and cycle performance.

[0198] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and various modifications and changes may be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A high-energy-density multi-element cathode material, characterized in that, Includes first material particles and second material particles; The first material particle includes a core and a carbon coating layer covering at least a portion of the surface of the core; The core body includes lithium manganese iron phosphate particles and lithium iron phosphate particles; The second material particles include lithium nickel cobalt manganese oxide particles; The particle size of the lithium manganese iron phosphate particles is smaller than that of the lithium iron phosphate particles. The particle size of the first material is smaller than that of the second material.

2. The high energy density multi-element cathode material according to claim 1, characterized in that, The particle size of the lithium manganese iron phosphate particles is 100nm-300nm; And / or, the particle size of the lithium iron phosphate particles is 1μm-5μm; And / or, the particle size of the lithium nickel cobalt manganese oxide particles is 8μm-30μm; And / or, the thickness of the carbon coating layer is 1nm-3nm.

3. The high energy density multi-element cathode material according to claim 1 or 2, characterized in that, The lithium manganese iron phosphate particles account for 10%-50% of the mass fraction of the high energy density multi-element cathode material; And / or, the lithium iron phosphate particles account for 10%-50% of the mass fraction of the high energy density multi-element cathode material; And / or, the lithium nickel cobalt manganese oxide particles account for 10%-50% of the mass fraction of the high energy density multi-element cathode material.

4. The high energy density multi-element cathode material according to claim 1, characterized in that, The high-energy-density multi-element cathode material has a compaction density of 2.7 g / cm³. 3 -3.7g / cm 3 .

5. A method for preparing a high-energy-density multi-element cathode material according to any one of claims 1-4, characterized in that, include: After grinding a first raw material mixture including lithium manganese iron phosphate precursor and lithium iron phosphate precursor, the system including the grinding product and carbon source is sintered to obtain the first material particles; wherein the particle size of the lithium manganese iron phosphate precursor is smaller than the particle size of the lithium iron phosphate precursor. The first material particles are mixed with second material particles including lithium nickel cobalt manganese oxide particles to obtain the high energy density multi-element cathode material; wherein the particle size of the first material particles is smaller than the particle size of the second material particles.

6. The method for preparing the high energy density multi-element cathode material according to claim 5, characterized in that, The particle size of the lithium manganese iron phosphate precursor is 100nm-300nm; And / or, the particle size of the lithium iron phosphate precursor is 1μm-4μm; And / or, the mass ratio of the carbon source to the milled product is (0.05-0.15):

1.

7. The method for preparing the high energy density multi-element cathode material according to claim 5 or 6, characterized in that, The grinding speed is 1800 rpm - 3000 rpm; And / or, the sintering temperature is 600℃-800℃, and the sintering time is 5h-12h.

8. A positive electrode plate, characterized in that, This includes the high energy density multi-element cathode material as described in any one of claims 1-4 or the high energy density multi-element cathode material prepared by the preparation method described in any one of claims 5-7.

9. A battery, characterized in that, Includes the positive electrode sheet as described in claim 8.

10. A battery pack, characterized in that, It includes at least two batteries as described in claim 9.

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