Electrode active material precursor, method for preparing the same, electrode active material, and battery

Abstract

An electrode active material precursor, a preparation method thereof, an electrode active material, and a battery, the electrode active material precursor comprising carbon-complexed oxide particles, the oxide satisfying formula (1): M a O b (1) wherein M elements are selected from one or more of transition metal elements with a relative atomic mass less than 65, and can be selected from one or more of Ni, Co, Fe, Mn, Zn, Mg, Ca, Cu, Sn, Mo, Ru, Ir, V, Nb, Cr, a>0, b>0, and the powder resistivity of the carbon-complexed oxide particles is less than 100 Ω·cm.

Description

Technical Field

[0001] This application relates to the field of lithium battery technology, and in particular to an electrode active material precursor, its preparation method, the electrode active material, and the battery. Background Technology

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development. With the rapid development of society today, the use of existing energy sources is becoming increasingly widespread. However, the harmful gases produced by fossil fuels have significant environmental impacts, and the scarcity of fossil fuels means they cannot meet the ever-growing energy demands of humanity. Therefore, finding a new clean energy source to replace fossil fuels is one of the most effective ways to solve this problem. Batteries, with their stable performance, high specific energy, and ability to be repeatedly cycled, have gained considerable attention. Electrode active materials, as a crucial component of batteries, are key to determining battery quality.

[0003] As the market, especially the power battery market, demands increasingly higher energy density and charging efficiency from batteries, higher requirements are also being placed on electrode active materials. Existing electrode active materials are currently unable to meet the energy density and specific capacity requirements of next-generation batteries. Furthermore, to improve battery performance, carbon coating post-treatment is often applied to electrode active materials to optimize electron transport within them. However, existing treatment methods cannot effectively improve battery performance. Summary of the Invention

[0004] This application aims to at least address one of the technical problems existing in the prior art. Therefore, one objective of this application is to provide an electrode active material precursor for preparing electrode active materials, thereby solving the problem that electrode active materials require carbon coating post-processing.

[0005] An embodiment of the first aspect of this application provides an electrode active material precursor comprising carbon composite oxide particles, wherein the oxide satisfies formula (1): M a O b (1); where M element is selected from one or more transition metal elements with a relative atomic mass of less than 65, and can be selected from one or more of Ni, Co, Fe, Mn, Zn, Mg, Ca, Cu, Mn, Sn, Mo, Ru, Ir, V, Nb, Cr, a>0, b>0, and the powder resistivity of carbon composite oxide particles is less than 100Ω·cm.

[0006] In the technical solution of this application, the electrode active material precursor includes carbon-composite oxide particles. The carbon elements in these particles exhibit high uniformity and good dispersion, resulting in low powder resistivity. This avoids the need for carbon coating post-processing in electrode active materials prepared using these particles as precursors, thus solving the adverse effects of conventional carbon coating post-processing, improving the stability of the electrode active material, and reducing manufacturing costs. Simultaneously, due to the low powder resistivity and good carbon dispersion of the carbon-composite oxide particles, the carbon layer coating integrity in the electrode active material prepared using these particles as precursors is high, resulting in low powder resistivity and improved battery capacity. Furthermore, by effectively utilizing the surface carbon layer in the carbon-composite oxide particles, the growth and aggregation of the electrode active material can be suppressed, limiting the size of the electrode active material to the submicron to nanometer level. This results in a shorter ion transport path, higher kinetics, better stability, and higher charging capacity during the charging process. Moreover, the atomic mass of transition metal elements in carbon composite oxide particles is relatively small, which makes the prepared electrode active material have a higher charging specific capacity, lighter residual material after discharge, and a smaller weight of the entire electrode sheet, which can further increase the proportion of electrode active material and energy density of the battery.

[0007] In any embodiment, the powder resistivity of the carbon composite oxide particles is less than 10 Ω·cm, and optionally less than 1 Ω·cm. Reducing the powder resistivity of the carbon composite oxide particles can further reduce the resistivity of the electrode active material prepared from them, thereby increasing the specific charging capacity.

[0008] In any embodiment, the mass content of carbon in the carbon composite oxide particles is 10% to 40%, optionally 20% to 30%. Controlling the mass content of carbon in the carbon composite oxide particles within a suitable range can result in carbon composite oxide particles with uniform particle size distribution and high carbon element dispersion through uniform carbon composite, and can also reduce the powder resistivity of the carbon composite oxide particles and the electrode active material prepared using them as precursors, thereby improving battery capacity.

[0009] In any embodiment, the median particle size Dv50 of the carbon composite oxide particles is 10–200 nm, and can be selected as 20–100 nm. Controlling the median particle size Dv50 of the carbon composite oxide particles within a suitable range is beneficial for controlling the particle size of the electrode active material prepared using it as a precursor, and is beneficial for preparing electrode active materials with low powder resistivity, suitable median particle size Dv50, and high charge specific capacity.

[0010] The second aspect of this application provides a method for preparing an electrode active material precursor, the method comprising the following steps: dispersing a carbon source in an aqueous solution containing M ions to obtain a mixed solution; adjusting the pH of the mixed solution to alkaline to obtain an alkaline mixed solution; subjecting the alkaline mixed solution to a precipitation reaction to obtain a precipitate; separating and washing the precipitate to obtain a precursor; and dehydrating and drying the precursor to prepare an electrode active material precursor; the electrode active material precursor comprises carbon-composite oxide particles, the oxide satisfying formula (1): M a O b (1); where M element is selected from one or more transition metal elements with a relative atomic mass of less than 65, and can be selected from one or more of Ni, Co, Fe, Mn, Zn, Mg, Ca, Cu, Mn, Sn, Mo, Ru, Ir, V, Nb, Cr, a>0, b>0, and the powder resistivity of carbon composite oxide particles is less than 100Ω·cm.

[0011] This preparation method is simple and easy to implement, suitable for the preparation of various carbon-composite oxide particles, and features low cost and ease of promotion and application. The method incorporates a carbon source during the reaction, serving as nucleation sites for the precipitate. This not only inhibits precipitate aggregation but also enhances the composite effect of carbon and oxides, reducing the resistivity of the carbon-composite oxide particles. The resulting carbon-composite oxide particles exhibit uniform particle size distribution, high dispersibility, low powder resistivity, and high carbon content.

[0012] In any embodiment, the pH value of the alkaline mixture is in the range of 9 to 13, and can be selected as 10 to 12. Controlling the pH value of the alkaline mixture within a suitable range is beneficial for preparing carbon composite oxide particles with low powder resistivity and a suitable median particle size Dv50.

[0013] In any embodiment, the precipitation reaction time is in the range of 4–15 h, and can be selected as 6–12 h. Controlling the precipitation reaction time within a suitable range is beneficial for preparing carbon composite oxide particles with low powder resistivity and a suitable median particle size Dv50.

[0014] In any embodiment, the reaction temperature of the precipitation reaction is in the range of 30–80°C, and can be selected as 40–60°C. Controlling the reaction temperature of the precipitation reaction within a suitable range is beneficial for preparing electrode active material precursors with low powder resistivity and a suitable median particle size Dv50. Moreover, the preparation method disclosed in this application has a low reaction temperature, unlike traditional preparation methods that require reactions at higher temperatures, thus reducing energy consumption, saving costs, and facilitating widespread application.

[0015] In any embodiment, a weak alkaline solution is added to the mixture before adjusting its pH to alkaline. The hydroxide ions in the weak alkaline solution slowly ionize from the solution, controlling the nucleation process of the precipitate, increasing the nucleation rate of M ions on the carbon source, preventing rapid growth and precipitation of the precipitate, and allowing sufficient time for the M ions adsorbed on the carbon source to disperse and nucleate. This improves the dispersibility of the carbon composite oxide particles, facilitates the control of the carbon composite oxide particle size, and is beneficial for preparing carbon composite oxide particles with low powder resistivity and a suitable median particle size Dv50.

[0016] In any embodiment, the weak alkaline solution is selected from one or more of ammonia water, ammonium bicarbonate aqueous solution, ammonium carbonate aqueous solution, sodium carbonate aqueous solution, and sodium bicarbonate aqueous solution. The above materials are simple and readily available, facilitating the widespread application of this method and reducing costs.

[0017] In any embodiment, the carbon source is selected from one or more of carbon black, acetylene black, Ketjen black, carbon nanotubes, graphene, graphite, carbon fiber, and carbon microspheres. This further expands the applicability of the method.

[0018] In any embodiment, the aqueous solution containing M ions is prepared by dissolving one or more of the following: sulfates, nitrates, oxalates, and halides containing the element M, in water. The ease of obtaining the raw materials further enhances the versatility of this method.

[0019] In any embodiment, the precursor is dried at 100–200°C for 6–20 h to obtain the electrode active material precursor. Controlling the drying temperature and time is beneficial for preparing carbon composite oxide particles with low powder resistivity and a suitable median particle size Dv50.

[0020] The third aspect of this application provides an electrode active material prepared using the electrode active material precursor of the above-described embodiments as raw material. The electrode active material prepared from this precursor has optimized powder resistivity and particle size, a uniform and complete carbon coating layer, and high electronic conductivity, charging capacity, and stability, thereby further improving battery capacity. This electrode active material does not require post-carbon coating processing, saving manufacturing costs.

[0021] A fourth aspect of this application provides a battery comprising the electrode active material described in the above embodiments. This battery has a high capacity.

[0022] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0023] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0024] Figure 1 A scanning electron microscope (SEM) image of Fe2O3@C provided in Example 3;

[0025] Figure 2 A transmission electron microscope (TEM) image of Fe2O3@C provided in Example 3;

[0026] Figure 3 An X-ray diffraction (XRD) pattern of Fe2O3@C provided in Example 3;

[0027] Figure 4 A transmission electron microscope (TEM) image of Li5FeO4@C provided in Example 25;

[0028] Figure 5 This is an X-ray diffraction (XRD) pattern of Li5FeO4@C provided for Example 25;

[0029] Figure 6 This is the first charging curve of Li5FeO4@C provided in Example 25. Detailed Implementation

[0030] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0032] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0033] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0034] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0035] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0036] In the description of the embodiments of this application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0037] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0038] In existing technologies, electrode active materials are often mixed with carbon materials for carbon coating post-treatment to improve battery capacity, especially for lithium-rich metal oxides, to address their poor stability and kinetics. However, the applicant found the following drawbacks in their research: First, the coating integrity is poor and highly random; second, the carbon coating post-treatment process easily causes a phase transition on the surface of lithium-rich metal oxides, leading to the release of active lithium from the material and the formation of lithium carbonate byproducts on the surface, which in turn reduces the specific capacity of the lithium-rich metal oxides; third, carbon coating post-treatment has strict requirements for the production environment, increasing production costs and hindering large-scale production; more importantly, the carbon coating post-treatment process also increases the agglomeration of lithium-rich metal oxides, leading to a further increase in particle size, which in turn worsens the delithiation kinetics and reduces the specific capacity.

[0039] Based on this, the first aspect of this application proposes an electrode active material precursor comprising carbon composite oxide particles, wherein the oxide satisfies formula (1): M a O b (1); where M element is selected from one or more transition metal elements with a relative atomic mass of less than 65, and can be selected from one or more of Ni, Co, Fe, Mn, Zn, Mg, Ca, Cu, Mn, Sn, Mo, Ru, Ir, V, Nb, Cr, a>0, b>0, and the powder resistivity of carbon composite oxide particles is less than 100Ω·cm.

[0040] Electrode active material precursors refer to raw materials that can be used to prepare electrode active materials. In some embodiments, the upper limit of the powder resistivity of carbon composite oxide particles can be selected from 50 Ω·cm, 40 Ω·cm, 30 Ω·cm, and 20 Ω·cm.

[0041] In this paper, the term "powder resistivity" refers to a parameter used to characterize the electrical conductivity of the material itself, which is different from the resistivity of the electrode. Typically, powder resistivity is measured using a testing instrument such as a four-probe analyzer, according to GB / T 30835-2014, "Carbon Composite Lithium Iron Phosphate Cathode Materials for Lithium-ion Batteries".

[0042] In some embodiments, the carbon-composite oxide particles are composite materials comprising carbon and oxide particles. It is understood that carbon and oxide particles can be composited in any manner, such as physical mixing or chemical composites. Specifically, carbon and oxide particles can be composited through methods such as stirring, grinding, ultrasonication, in-situ growth, grafting, and coating.

[0043] In some implementations, M a O bSelected from one or more of the following: M 1 O, M 2 O2, M 3 2O5, M 4 2O3, M 5 O. Among them, M 1 Including one or more of Ni, Co, Fe, Mn, Zn, Mg, Ca, and Cu, M 2 Includes one or more of Mn, Sn, Mo, Ru, and Ir, M 3 Including one or more of V, Nb, Cr, and Mo, M 4 Including one or more of Fe, Cr, V, and Mo, M 5 It includes one or more of Co, V, Cr, and Mo.

[0044] Transition metals refer to a series of metallic elements in the d-block and ds-block of the periodic table. The d-block elements include elements in groups IIIB to VIIB and VIII of the periodic table, while the ds-block elements include elements in groups IB to IIB of the periodic table.

[0045] The electrode active material precursor provided in this application includes carbon-composite oxide particles, in which the carbon elements exhibit high uniformity and good dispersion, resulting in low powder resistivity. This avoids the need for carbon coating post-processing in electrode active materials prepared using these precursors, solving the adverse effects of conventional carbon coating post-processing, improving the stability of the electrode active material, and reducing manufacturing costs. Simultaneously, due to the low powder resistivity and good carbon dispersion of the carbon-composite oxide particles, the carbon layer coating integrity in the electrode active material prepared using these precursors is high, resulting in low powder resistivity and thus increasing battery capacity. Furthermore, by effectively utilizing the surface carbon layer in the carbon-composite oxide particles, the growth and aggregation of the electrode active material can be suppressed, limiting the size of the electrode active material to the submicron to nanometer scale. This results in a shorter ion transport path, higher kinetics, better stability, and higher charging capacity during the charging process. Moreover, the atomic mass of transition metal elements in carbon composite oxide particles is relatively small, which makes the prepared electrode active material have a higher charging specific capacity, lighter residual material after discharge, and a smaller weight of the entire electrode sheet, which can further increase the proportion of electrode active material and energy density of the battery.

[0046] In some embodiments, the powder resistivity of the carbon composite oxide particles is less than 10 Ω·cm, optionally less than 1 Ω·cm, and the upper limit of the powder resistivity can be selected from 9 Ω·cm, 8 Ω·cm, 7 Ω·cm, 6 Ω·cm, 5 Ω·cm, 4.25 Ω·cm, 3.58 Ω·cm, 2.78 Ω·cm, 2.28 Ω·cm, 2.15 Ω·cm, 1.8 Ω·cm, 1.02 Ω·cm, 0.98 Ω·cm, 0.95 Ω·cm, 0.56 Ω·cm, 0.42 Ω·cm, 0.31 Ω·cm, 0.3 Ω·cm, 0.28 Ω·cm, 0.26 Ω·cm, 0.25 Ω·cm, 0.24 Ω·cm, 0.23 Ω·cm, 0.22 Ω·cm, 0.23 Ω·cm, and 0.19 Ω·cm. Reducing the powder resistivity of carbon composite oxide particles can lower the resistivity of the electrode active material prepared from them, thereby increasing the charge capacity of the electrode active material.

[0047] In some embodiments, the mass content of carbon in the carbon composite oxide particles is 10% to 40%, optionally 20% to 30%. In some embodiments, the mass content of carbon in the carbon composite oxide particles can be selected from 10%, 18%, 20%, 22%, 23%, 24%, 25%, 30%, and 40%.

[0048] In some embodiments, a carbon content analyzer is used to test the mass content of carbon in the carbon-composite oxide particles. In this document, the mass content of carbon in the carbon-composite oxide particles can be adjusted by changing the mass of the carbon source added during the preparation of the carbon-composite oxide.

[0049] Excessive carbon content in carbon-composite oxide particles can lead to a decrease in the proportion of oxides in the particles, resulting in carbon material agglomeration and poor composite effect. Controlling the carbon content within a suitable range allows for the production of carbon-composite oxide particles with uniform particle size distribution and high carbon dispersion through homogeneous carbon composite processes. Furthermore, it can reduce the resistivity of the carbon-composite oxide particles and the powder resistivity of electrode active materials prepared using them as precursors, thereby improving battery capacity.

[0050] In some embodiments, the median particle size Dv50 of the carbon composite oxide particles is 10–200 nm, and can be selected as 20–100 nm. In some embodiments, the median particle size Dv50 of the carbon composite oxide particles can be selected from 20 nm, 30 nm, 40 nm, 45 nm, 47 nm, 58 nm, 60 nm, 61 nm, 62 nm, 65 nm, 68 nm, 70 nm, 75 nm, 80 nm, 83 nm, 94 nm, 100 nm, 110 nm, and 200 nm.

[0051] In this paper, the median particle size Dv50 of carbon composite oxide particles has a well-known meaning in the art. The median particle size Dv50, also known as the average particle size, represents the particle size corresponding to a cumulative volume distribution percentage of 50% for the material. It can be determined using methods and instruments known in the art. For example, it can be determined using a laser particle size analyzer, referring to GB / T 19077-2016 Particle Size Distribution Laser Diffraction Method.

[0052] If the particle size of carbon-composite oxide particles is too small, it can lead to an excessively large specific surface area and surface energy, causing the carbon-composite oxide particles to agglomerate and reducing their dispersibility during the preparation of electrode active materials. Conversely, if the particle size of carbon-composite oxide particles is too large, it can reduce the composite effect between carbon and oxide particles. Controlling the median particle size Dv50 of carbon-composite oxide particles within a suitable range is beneficial for controlling the particle size of electrode active materials prepared using it as a precursor, and facilitates the preparation of electrode active materials with low powder resistivity, suitable median particle size Dv50, and high specific charge capacity.

[0053] The second aspect of this application provides a method for preparing the above-mentioned electrode active material precursor, the method comprising the following steps: dispersing a carbon source in an aqueous solution containing M ions to obtain a mixed solution; adjusting the pH of the mixed solution to alkaline to obtain an alkaline mixed solution; subjecting the alkaline mixed solution to a precipitation reaction to obtain a precipitate; separating and washing the precipitate to obtain a precursor; and dehydrating and drying the precursor to prepare the electrode active material precursor; the electrode active material precursor comprises carbon composite oxide particles, the oxide satisfying formula (1): M a O b (1); where M element is selected from one or more transition metal elements with a relative atomic mass of less than 65, and can be selected from one or more of Ni, Co, Fe, Mn, Zn, Mg, Ca, Cu, Mn, Sn, Mo, Ru, Ir, V, Nb, Cr, a>0, b>0, and the powder resistivity of carbon composite oxide particles is less than 100Ω·cm.

[0054] In some embodiments, the aqueous solution of M ions is prepared by dissolving a salt containing M ions in water. In some embodiments, the concentration of element M in the mixture is 0.5–10 mol / L. In some embodiments, the carbon source in the mixture is dispersed by various dispersion methods, such as ultrasonication or stirring. Dispersing the carbon source in the aqueous solution containing M ions allows the M ions to be uniformly adsorbed onto the carbon source. The carbon source can act as a matrix in the subsequent precipitation reaction, and the M ions, as nucleation reactants, are uniformly dispersed on the matrix, preventing the precipitate from agglomerating and growing, and inhibiting the growth of oxide particles.

[0055] In some embodiments, the pH value of the mixed solution is controlled by adjusting the flow rate and volume of the added strong alkali solution. The strong alkali solution can be selected from one or more of sodium hydroxide and potassium hydroxide. Hydroxide ions in the strong alkali solution can be rapidly ionized from the solution, used to control the growth process of the precipitate. Optionally, the concentration of the strong alkali solution is 1–10 mol / L. In some embodiments, the strong alkali solution is added to the mixed solution after stirring for a period of time. In some embodiments, the strong alkali solution is added to the mixed solution after stirring for 0.1–2 hours. In some embodiments, the strong alkali solution is added to the mixed solution after stirring for 1 hour. In some embodiments, the strong alkali solution and the mixed solution are added to the reactor in parallel flow, with the flow rate of the strong alkali solution being 0.01–0.5 times that of the mixed solution. In some embodiments, the strong alkali solution and the mixed solution are added to the reactor in parallel flow, with the flow rate of the strong alkali solution being 0.1 times that of the mixed solution. Before adding the strong alkaline solution, stirring the mixture improves the dispersion of M ions and the carbon source, aids in the adsorption of M ions on the carbon source, and prevents the carbon composite oxide particles from growing rapidly. This helps to prepare carbon composite oxide particles with high dispersion and uniform particle size.

[0056] In some embodiments, the precipitation reaction is carried out under stirring conditions. In some embodiments, the stirring intensity is 100–500 rpm. In some embodiments, after the reaction is complete, the precipitate is separated by filtration or centrifugation. In some embodiments, the precipitate is washed several times with distilled water or anhydrous ethanol to clean it. In some embodiments, the washed product is dried in an oven to obtain carbon-composite oxide particles.

[0057] A precipitation reaction is a reaction in which the target product in solution is precipitated out in solid form. In this paper, M ions are precipitated in an alkaline mixture to obtain a precipitate.

[0058] This preparation method is simple and easy to implement, suitable for the preparation of various carbon-composite oxide particles, and features low cost and ease of promotion and application. The method incorporates a carbon source during the reaction, serving as nucleation sites for the precipitate. This not only inhibits precipitate aggregation but also enhances the composite effect of carbon and oxides, reducing the resistivity of the carbon-composite oxide particles. The resulting carbon-composite oxide particles exhibit uniform particle size distribution, high dispersibility, low powder resistivity, and high carbon content.

[0059] In some embodiments, the pH value of the alkaline mixture is in the range of 9 to 13, and may be selected from the range of 10 to 12. In some embodiments, the pH value of the alkaline mixture may be selected from any one of 8, 9, 10, 11, 11.6, 11.8, 12, and 13.

[0060] Adjusting the pH of the alkaline mixture can control the nucleation and growth process of the precipitate. If the pH of the alkaline mixture is too high, the precipitation reaction time is extremely short, the precipitation process is difficult to control, and large precipitate agglomerates are easily formed. If the pH of the alkaline mixture is too low, aqueous solutions containing M ions are less likely to form precipitates. Controlling the pH of the alkaline mixture within a suitable range is beneficial for preparing carbon composite oxide particles with low powder resistivity and a suitable median particle size Dv50.

[0061] In some embodiments, the precipitation reaction time is in the range of 4 to 15 hours, and can be selected from the range of 6 to 12 hours. In some embodiments, the precipitation reaction time can be selected from any one of 4 hours, 6 hours, 8 hours, 12 hours, and 15 hours.

[0062] Controlling the reaction time of the precipitation reaction can regulate the nucleation and growth process of the precipitate. Too short a reaction time can lead to incomplete nucleation and growth of the precipitate, resulting in poor crystallinity. Too long a reaction time can cause the precipitate to continue growing after nucleation, resulting in excessively large particles. Controlling the reaction time within a suitable range is beneficial for preparing carbon composite oxide particles with low powder resistivity and a suitable median particle size (Dv50).

[0063] In some embodiments, the reaction temperature of the precipitation reaction is in the range of 30–80°C, and can be selected from the range of 40–60°C. In some embodiments, the reaction temperature of the precipitation reaction can be selected from any one of 40°C, 50°C, 60°C, and 80°C.

[0064] Controlling the reaction temperature of the precipitation reaction can regulate the nucleation and growth process of the precipitate. Too low a reaction temperature can lead to incomplete nucleation and growth of the precipitate, resulting in poor crystallinity. Too high a reaction temperature can cause the precipitate to grow too rapidly after nucleation, forming large particles. Controlling the reaction temperature within a suitable range is beneficial for preparing electrode active material precursors with low powder resistivity and a suitable median particle size Dv50. Furthermore, the preparation method disclosed in this application involves a low reaction temperature, unlike traditional methods for preparing electrode active materials or their precursors that require higher temperatures, thus reducing energy consumption, saving costs, and facilitating widespread application.

[0065] In some embodiments, a weak alkaline solution is added to the mixture before adjusting its pH to alkaline. The hydroxide ions in the weak alkaline solution slowly ionize from the solution, which can control the nucleation process of the precipitate, increase the nucleation rate of M ions on the carbon source, prevent the precipitate from growing and precipitating rapidly, and allow sufficient time for the M ions adsorbed on the carbon source to disperse and nucleate. This improves the dispersibility of the carbon composite oxide particles, facilitates the control of the particle size of the carbon composite oxide, and is beneficial for preparing carbon composite oxide particles with low powder resistivity and a suitable median particle size Dv50.

[0066] In some embodiments, the weak alkali solution is added to the mixture after stirring for a period of time. In other embodiments, the weak alkali solution is added to the mixture after stirring for 0.5 hours. Stirring the mixture for a period of time improves the dispersion of M ions and the carbon source, aiding in the adsorption of M ions on the carbon source, and contributing to the preparation of electrode active material precursors with high dispersion and uniform particle size. In some embodiments, the weak alkali solution and the mixture are added to the reactor in a parallel flow, with the flow rate of the weak alkali solution being 0.1-0.7 times that of the mixture, preferably 0.2-0.6 times, and more preferably 0.4 times. Controlling the flow rate of the weak alkali solution controls the nucleation rate, which is beneficial for preparing carbon composite oxide particles with high dispersion and uniform particle size.

[0067] In some embodiments, the weak base solution is selected from one or more of ammonia water, ammonium bicarbonate aqueous solution, ammonium carbonate aqueous solution, sodium carbonate aqueous solution, and sodium bicarbonate aqueous solution. In some embodiments, the concentration of the weak base solution is preferably 2-8 mol / L. The above materials are simple and readily available, facilitating the widespread application of this method and reducing costs.

[0068] In some embodiments, the carbon source is selected from one or more of carbon black, acetylene black, Ketjen black, carbon nanotubes, graphene, graphite, carbon fiber, and carbon microspheres. It is understood that any carbon material can be used as a carbon source, further expanding the applicability of this method.

[0069] In some embodiments, the aqueous solution containing M ions is prepared by dissolving one or more of the following: sulfates, nitrates, oxalates, and halides containing the M element in water. The ease of obtaining the raw materials further enhances the versatility of this method.

[0070] In some embodiments, the precursor is dried at 100–200°C for 6–20 hours to obtain the electrode active material precursor. Too low a drying temperature or time can lead to incomplete removal of moisture from the precursor, while too high a drying temperature or too long a drying time can cause the carbon composite oxide particles to agglomerate and grow. Controlling the drying temperature and time is beneficial for preparing carbon composite oxide particles with low powder resistivity and a suitable median particle size Dv50.

[0071] The third aspect of this application provides an electrode active material prepared using the electrode active material precursor of any of the above embodiments as raw material. The electrode active material prepared from this electrode active material precursor has optimized powder resistivity and particle size, a uniform and complete carbon coating layer, and high electronic conductivity, charging capacity, and stability, thereby further improving battery capacity. This electrode active material does not require post-carbon coating processing, saving manufacturing costs.

[0072] An embodiment of the fourth aspect of this application provides an electrode active material comprising carbon-coated metal oxide particles, wherein the metal oxide particles satisfy formula (2): A c M d O e (2); where A is selected from one or more alkali metal elements or alkaline earth metal elements, M is selected from one or more transition metal elements with a relative atomic mass of less than 65, c>0, d>0, e>0.

[0073] Alkali metals refer to the six metallic elements in Group IA of the periodic table, excluding hydrogen (H): lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).

[0074] Alkaline earth metals refer to Group IIA elements in the periodic table, including six elements: beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).

[0075] Transition metals refer to a series of metallic elements in the d-block and ds-block of the periodic table. The d-block elements include elements in groups IIIB to VIIB and VIII of the periodic table, while the ds-block elements include elements in groups IB to IIB of the periodic table.

[0076] The transition metal elements in the electrode active material provided in this embodiment have relatively small atomic masses. The carbon-coated metal oxide particles have a higher charge capacity when containing the same number of A ions. The residual material after discharge is lighter and occupies a smaller weight of the entire electrode sheet, which can improve the proportion of electrode active material and energy density of the battery.

[0077] In some embodiments, element A is selected from one or more of Li, Na, K, Mg, and Ca. These metal oxides possess high specific capacity and high energy density, are made from abundant and readily available raw materials, and are suitable for various batteries, demonstrating excellent application prospects.

[0078] In some embodiments, the metal oxide is selected from Li₂M₂. 1 O2, Li2M 2 O3, Li3M 3 O4, Li5M 4 O4, Li6M 5 One or more of O4, of which M 1 Selected from one or more of Ni, Co, Fe, Mn, and Cu, M 2 Selected from one or more of Mn, Sn, Mo, Ru, and Ir, M 3 Including one or more of V, Nb, Cr, and Mo, M 4 Selected from one or more of Fe, Cr, V, and Mo, M5 It includes one or more of Co, V, Cr, and Mo.

[0079] In some embodiments, the morphology, composition, structure, surface valence state, and electrochemical performance of the electrode active material can be adjusted by controlling the type and proportion of element M in the aforementioned metal oxide. In some embodiments, element M has abundant valence states, and the valence states of element M in the metal oxide are all lower than its highest oxidation valence state. The aforementioned metal oxide exhibits high specific capacity, high energy density, and excellent application prospects.

[0080] In some embodiments, the metal oxide is selected from one or more of Li₂NiO₂, Li₂CuO₂, Li₂MnO₃, Li₃VO₄, Li₅FeO₄, and Li₆CoO₄. The above-mentioned methods for preparing lithium-rich metal oxides are mature, possess high specific capacity and high energy density, and can meet the needs of next-generation rechargeable lithium batteries for large-scale grid storage and electric vehicles, showing great application potential.

[0081] In some embodiments, the molar ratio of element A to element M is c:d≥2, based on the total number of moles of elements in the electrode active material. The metal oxide contains a greater number of A atoms than M atoms, resulting in a higher specific capacity of the electrode active material.

[0082] In some embodiments, the carbon content of the electrode active material is 2 wt% to 20 wt%, optionally 5 wt% to 15 wt%, based on the total weight of the electrode active material. In other embodiments, the carbon content of the electrode active material is 2 wt% to 20 wt%, optionally 5 wt% to 15 wt%, based on the total weight of the carbon-coated metal oxide. Appropriate carbon coating content results in low powder resistivity, high material stability and electronic conductivity in the electrode active material, and excellent carbon coating effect, which is beneficial for improving battery capacity.

[0083] In some embodiments, the electrode active material includes a dopant element, wherein the ratio of the solubility product constant of the hydroxide of the dopant element to that of the hydroxide of element M is greater than or equal to 10. -5 10 5 The doping element can be selected from Mg, Zn, Al, or Ti. Including doping elements in the electrode active material can further improve its stability. In some embodiments, the solubility product refers to the dissolution equilibrium constant of the precipitate, denoted by K. sp This indicates that the solubility product reflects the dissolving power of a sparingly soluble electrolyte. The ratio of the solubility product constants of the hydroxide of the doped element and the hydroxide of element M is greater than or equal to 10. -5 10 5This avoids situations where the solubility product of the hydroxide of the dopant element and the hydroxide of the M element differs too much, leading to uneven doping or even the precipitation of the dopant element alone. This helps to maximize the effectiveness of the dopant element and improve the charging capacity and energy density of the electrode active material.

[0084] In some embodiments, the resistivity of the carbon-coated metal oxide particles is less than 1000 Ω·cm, optionally less than 350 Ω·cm, optionally less than 10 Ω·cm, and further optionally less than 5 Ω·cm. In some embodiments, the resistivity of the carbon-coated metal oxide particles is optionally less than 100 Ω·cm, optionally less than 50 Ω·cm. In some embodiments, the powder resistivity of the carbon-coated metal oxide particles can be selected as 1.24 Ω·cm, 2.12 Ω·cm, 2.83 Ω·cm, 3.18 Ω·cm, 6.54 Ω·cm, 10.13 Ω·cm, 17.24 Ω·cm, 21.34 Ω·cm, 25.36 Ω·cm, 32.41 Ω·cm, 35.76 Ω·cm, 45.32 Ω·cm, 48.35 Ω·cm, 50.13 Ω·cm, 56.21 Ω·cm, 60.28 Ω·cm, 81.22 Ω·cm, 89.13 Ω·cm, 236.11 Ω·cm, and 313.87 Ω·cm. The carbon-coated metal oxide particles provided in this embodiment have low powder resistivity, higher material stability and electronic conductivity, and a better carbon coating effect, which is beneficial for improving battery capacity.

[0085] In some embodiments, the median particle size Dv50 of the carbon-coated metal oxide particles is in the range of 100–900 nm, optionally in the range of 300–700 nm. In some embodiments, the median particle size Dv50 of the carbon-coated metal oxide particles is in the range of 100–800 nm, optionally in the range of 400–900 nm, or optionally in the range of 200–600 nm. The carbon-coated metal oxide particles provided in this application have a suitable median particle size, resulting in a short ion transport path and high kinetics during charging, leading to a higher specific capacity. Simultaneously, they possess a suitable specific surface area, making them less prone to aggregation that could reduce their specific capacity.

[0086] The fifth aspect of this application provides a method for preparing an electrode active material, the method comprising: providing carbon composite oxide particles, wherein the oxide satisfies formula (1): M a O b (1); where M element is selected from one or more transition metal elements with a relative atomic mass less than 65, a>0, b>0; and carbon composite metal oxide particles and A source are sintered to obtain carbon-coated metal oxide particles, the metal oxide satisfying equation (2): A c Md O e (2); where A is selected from one or more alkali metal elements or alkaline earth metal elements, M is selected from one or more transition metal elements with a relative atomic mass of less than 65, c>0, d>0, e>0.

[0087] In some embodiments, the carbon-composite oxide particles are composite materials comprising carbon and oxide particles. It is understood that carbon and oxide particles can be composited in any manner, such as physical mixing or chemical composites. Specifically, the composite of carbon and oxide particles can be achieved through methods such as stirring, grinding, ultrasonication, in-situ growth, and grafting.

[0088] In some implementations, M a O b Selected from one or more of the following: M 1 O, M 2 O2, M 3 2O5, M 4 2O3, M 5 O. Among them, M 1 Including one or more of Ni, Co, Fe, Mn, Zn, Mg, Ca, and Cu, M 2 Includes one or more of Mn, Sn, Mo, Ru, and Ir, M 3 Including one or more of V, Nb, Cr, and Mo, M 4 Including one or more of Fe, Cr, V, and Mo, M 5 It includes one or more of Co, V, Cr, and Mo.

[0089] In some embodiments, source A is a raw material containing any one or more alkali metals or alkaline earth metals, and may be selected from one or more of lithium hydroxide, lithium carbonate, lithium oxide, lithium oxalate, lithium acetate, sodium hydroxide, sodium carbonate, sodium oxide, sodium oxalate, and sodium acetate.

[0090] In some embodiments, the carbon-composite metal oxide particles and the A source are mixed uniformly before sintering to achieve uniform sintering. The carbon-composite metal oxide particles and the A source can be mixed uniformly in any way, such as by mechanical stirring, ball milling, or chemical mixing to improve the uniformity of the mixture.

[0091] In some embodiments, the sintering process is carried out in an atmosphere including an inert gas to improve the purity of the sintered product. The atmosphere can be one or more of nitrogen, argon, or a hydrogen / argon mixture. The inert gas can be any inert gas, such as nitrogen, argon, etc.

[0092] In some embodiments, carbon-composite metal oxide particles and source A are sintered, and the sintered product is crushed and / or sieved to obtain carbon-coated metal oxide particles.

[0093] The carbon-coated metal oxide particles prepared by the above method exhibit high integrity of the external carbon layer coating and low powder resistivity. Furthermore, the surface carbon layer in the carbon-coated oxide particles effectively inhibits the growth and agglomeration of the metal oxide particles during sintering, limiting the particle size to submicron to nanometer levels. This results in shorter ion transport paths, higher kinetics, and higher specific capacity during charging. Simultaneously, it avoids post-coating processing of the carbon-coated metal oxide particles, effectively improving their stability and saving manufacturing costs.

[0094] In some embodiments, the powder resistivity of the carbon-composite oxide particles is less than 100 Ω·cm, optionally less than 10 Ω·cm. The low powder resistivity of the carbon-composite oxide particles demonstrates high uniformity and good dispersion of carbon composites, eliminating the need for carbon coating post-processing in electrode active materials prepared using them as precursors. This solves the adverse effects of conventional carbon coating post-processing, improves the stability of electrode active materials, and reduces manufacturing costs. Simultaneously, due to the low powder resistivity and good carbon dispersion of the carbon-composite oxide particles, the carbon layer in the carbon-coated metal oxide particles prepared using them as precursors has high integrity, and the powder resistivity of the carbon-coated metal oxide particles is low, thereby increasing battery capacity.

[0095] In some embodiments, the median particle size Dv50 of the carbon composite oxide particles is in the range of 10–200 nm, and can be selected as 20–100 nm. Controlling the median particle size of the carbon composite oxide particles within a suitable range is beneficial for controlling the particle size of the prepared carbon-coated metal oxide, reducing the powder resistivity of the carbon-coated metal oxide, and improving its specific charging capacity.

[0096] In some embodiments, the carbon content in the carbon-composite oxide particles is 10 wt% to 40 wt%, optionally 20 wt% to 30 wt%, based on the total weight of the carbon-composite oxide particles. Controlling the carbon content in the carbon-composite oxide particles within a suitable range is beneficial for reducing the powder resistivity of the carbon-coated metal oxide particles and improving their charge capacity.

[0097] In some embodiments, the sintering temperature is in the range of 500–700°C, preferably in the range of 550–650°C; and / or the sintering time is in the range of 4–20 h, preferably in the range of 8–12 h. In some embodiments, the sintering temperature can be selected from 550°C, 590°C, 600°C, 610°C, 620°C, and 650°C. In some embodiments, the sintering time can be selected from 8 h, 10 h, and 12 h.

[0098] Too low a sintering temperature or too short a sintering time can lead to poor crystallinity and incomplete phase formation in the carbon-coated metal oxide particles, resulting in low specific charge capacity. Too high a sintering temperature or too long a sintering time can lead to an excessively large median particle size (Dv50) in the carbon-coated metal oxide particles, increasing the delithiation pathway, reducing kinetics, and further reducing specific charge capacity. Controlling the sintering temperature and / or time within a suitable range is beneficial for preparing carbon-coated metal oxide particles with low powder resistivity, a suitable median particle size (Dv50), and high specific charge capacity.

[0099] In some embodiments, source A is selected from one or more oxides, salts, or hydroxides of alkali metals or alkaline earth metals. For example, one or more of lithium oxide, sodium oxide, and magnesium oxide. This method has a wide range of applications and can synthesize various carbon-coated metal oxide particles as needed.

[0100] In some embodiments, source A is selected from one or more of lithium hydroxide, lithium carbonate, lithium oxide, lithium oxalate, and lithium acetate, and the molar ratio of lithium in source A to element M in the carbon-composite oxide particles is in the range of 5.5 to 1. In some embodiments, the molar ratio of lithium in source A to element M in the carbon-composite oxide particles is in the range of 5.2 to 1. The lithium-rich metal oxide prepared by this method exhibits low powder resistivity and high specific charge capacity.

[0101] In some embodiments, the carbon-composite oxide particles are prepared by liquid-phase precipitation. Liquid-phase precipitation involves a precipitation reaction, in which the target product in solution is precipitated out in solid form. This method is simple, low-cost, and easily applicable on a large scale.

[0102] An embodiment of the sixth aspect of this application provides an electrode comprising a current collector and an electrode active material layer disposed on at least one surface of the current collector, the electrode active material layer comprising the electrode active material in any embodiment. This electrode enables the battery to have high capacity.

[0103] An embodiment of the seventh aspect of this application provides a battery, including the electrode active material or electrode sheet as described in any of the embodiments. The battery has a high capacity.

[0104] Example

[0105] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0106] The following examples provide an electrode active material precursor. Taking Fe2O3 as an example, Fe(OH)3 precursor is obtained by hydrolysis and precipitation, and Fe2O3@C is obtained by dehydration and drying. The specific preparation method is as follows:

[0107] Example 1

[0108] The features and performance of this application will be further described in detail below with reference to embodiments:

[0109] Using FeSO4·7H2O as raw material, distilled water was added to prepare a solution with an Fe element concentration of 5 mol / L; then, carbon black was added to the above solution under stirring, and an appropriate amount of carbon black was added so that the mass content of carbon element in the product was 25%, thus obtaining a mixed solution.

[0110] Prepare solution A: Prepare a 5 mol / L ammonium bicarbonate solution. Prepare solution B: Prepare a 2 mol / L sodium hydroxide solution. Add the mixture to the reaction vessel. Solution A is added to the reaction vessel 0.5 hours after the addition of the mixture, and solution B is added to the reaction vessel 1 hour after the addition of the mixture, resulting in an alkaline mixture. The flow rate of solution A is 0.4 times the flow rate of the mixture, and the flow rate of solution B is 0.1 times the flow rate of the mixture. The pH value of the alkaline mixture is 9. The alkaline mixture undergoes a precipitation reaction at a stirring intensity of 300 rpm, a reaction temperature of 50℃, and a reaction time of 8 hours.

[0111] After the reaction is complete, the precipitate is filtered or centrifuged, and the precipitate is repeatedly washed with distilled water or anhydrous ethanol several times to obtain the precursor.

[0112] The precursor is dried in an oven at 150°C for 12 hours to obtain carbon-composite ferric oxide particles, denoted as Fe2O3@C.

[0113] Example 2

[0114] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 1, except that the pH value of the alkaline mixture in Example 1 is set to 10, while other operating procedures remain unchanged.

[0115] Example 3

[0116] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 1, except that the pH value of the alkaline mixture in Example 1 is set to 11, while other operating procedures remain unchanged.

[0117] Example 4

[0118] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that the pH value of the alkaline mixture in Example 3 is set to 12, while other operating procedures remain unchanged.

[0119] Example 5

[0120] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that the pH value of the alkaline mixture in Example 3 is set to 13, while other operating procedures remain unchanged.

[0121] Example 6

[0122] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that the reaction time of the precipitation reaction in Example 3 is set to 4 hours, while other operation procedures remain unchanged.

[0123] Example 7

[0124] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that the reaction time of the precipitation reaction in Example 3 is set to 6 hours, while other operation procedures remain unchanged.

[0125] Example 8

[0126] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that the reaction time of the precipitation reaction in Example 3 is set to 12h, while other operation procedures remain unchanged.

[0127] Example 9

[0128] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that the reaction time of the precipitation reaction in Example 3 is set to 15h, while other operation procedures remain unchanged.

[0129] Example 10

[0130] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that the reaction temperature of the precipitation reaction in Example 3 is set to 30°C, while other operation procedures remain unchanged.

[0131] Example 11

[0132] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that the reaction temperature of the precipitation reaction in Example 3 is set to 40°C, while other operation procedures remain unchanged.

[0133] Example 12

[0134] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that the reaction temperature of the precipitation reaction in Example 3 is set to 60°C, while other operation procedures remain unchanged.

[0135] Example 13

[0136] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that the reaction temperature of the precipitation reaction in Example 3 is set to 80°C, while other operation procedures remain unchanged.

[0137] Example 14

[0138] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that the amount of carbon black added in Example 3 is reduced so that the mass content of carbon element in the product is 10%.

[0139] Example 15

[0140] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that the amount of carbon black added in Example 3 is reduced so that the mass content of carbon element in the generated product is 20%, while other operation processes remain unchanged.

[0141] Example 16

[0142] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that the amount of carbon black added in Example 3 is increased so that the mass content of carbon element in the generated product is 30%, while other operation procedures remain unchanged.

[0143] Example 17

[0144] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that the amount of carbon black added in Example 3 is increased so that the mass content of carbon element in the generated product is 40%, while other operation processes remain unchanged.

[0145] Example 18

[0146] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that the carbon source in Example 3 is replaced by carbon nanotubes (CNTs), and the mass of carbon nanotubes added makes the mass content of carbon element in the product 20%, while other operation procedures remain unchanged.

[0147] Example 19

[0148] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that the carbon source in Example 3 is replaced with graphite (Gr), and the amount of graphite added makes the carbon content in the product 18% by mass, while other operation procedures remain unchanged.

[0149] Example 20

[0150] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that: the metal salt FeSO4·7H2O in Example 3 is replaced with NiSO4·6H2O, the pH value of the alkaline mixture is set to 11.8, the reaction time of the precipitation reaction is set to 8h, the reaction temperature is changed to 55℃, and the amount of carbon black added is such that the mass content of carbon element in the product is 23%, while other operating procedures remain unchanged.

[0151] Example 21

[0152] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that: the metal salt FeSO4·7H2O in Example 3 is replaced with CuSO4·5H2O, the pH value of the alkaline mixture is set to 11.6, the reaction time of the precipitation reaction is set to 6h, the reaction temperature is set to 45℃, and the amount of carbon black added is such that the mass content of carbon element in the product is 22%, while other operating procedures remain unchanged.

[0153] Example 22

[0154] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that: the metal salt FeSO4·7H2O in Example 3 is replaced with CoSO4·7H2O, the pH value of the alkaline mixture is set to 12, the reaction time of the precipitation reaction is set to 10h, the reaction temperature is set to 60℃, and the amount of carbon black added is such that the mass content of carbon element in the product is 24%, while other operating procedures remain unchanged.

[0155] Comparative Example 1

[0156] This embodiment provides an electrode active material precursor, the preparation method of which is roughly the same as that of Example 3, except that: the pH value of the alkaline mixture in Example 3 is set to 8, and the amount of carbon black added is such that the mass content of carbon element in the product is 45%, while other operating procedures remain unchanged.

[0157] Comparative Example 2

[0158] This comparative example provides an electrode active material precursor, whose preparation method is roughly the same as that of Comparative Example 1, except that: the pH value of the alkaline mixture in Comparative Example 1 is set to 14, the reaction time of the precipitation reaction is set to 2 hours, the mass content of carbon in the product is 5%, and other operating procedures remain unchanged.

[0159] Comparative Example 3

[0160] This comparative example provides an electrode active material precursor, whose preparation method is roughly the same as that of Comparative Example 1, except that: the pH value of the alkaline mixture in Comparative Example 1 is set to 11, the reaction time of the precipitation reaction is set to 2 hours, the reaction temperature of the precipitation reaction is set to 90°C, and the mass content of carbon in the product is 16%, while other operating procedures remain unchanged.

[0161] Comparative Example 4

[0162] This comparative example provides an electrode active material precursor, whose preparation method is roughly the same as that of Comparative Example 1, except that: the pH value of the alkaline mixture in Comparative Example 1 is set to 11, the reaction time of the precipitation reaction is set to 20 h, the reaction temperature of the precipitation reaction is set to 25 °C, the mass content of carbon in the product is 35%, and other operating procedures remain unchanged.

[0163] Comparative Example 5

[0164] This comparative example provides an electrode active material precursor, whose preparation method is roughly the same as that of comparative example 1. The difference is that carbon black is not added in comparative example 1, the pH value of the alkaline mixture in comparative example 1 is set to 11, the reaction time of the precipitation reaction is set to 8 hours, the reaction temperature of the precipitation reaction is changed to 50°C, and other operation procedures remain unchanged.

[0165] Comparative Example 6

[0166] This comparative example provides an electrode active material precursor, whose preparation method is roughly the same as that of comparative example 1. The difference is that the Fe2O3 in comparative example 5 and carbon black are mixed by ball milling at a carbon mass ratio of 25% to prepare comparative example 6. The ball milling speed is 200 rpm and the ball milling time is 6 hours. The product obtained is denoted as Fe2O3 / C.

[0167] The relevant parameters of the carbon composite oxide particles of Examples 1-22 and Comparative Examples 1-6 are shown in Table 1 below.

[0168] Table 1: Reaction parameters of Examples 1-22 and Comparative Examples 1-6

[0169]

[0170] The following examples and comparative examples all use materials prepared by the methods described in the above examples as precursors for electrode active materials, unless otherwise specified.

[0171] Example 23

[0172] The features and performance of this application will be further described in detail below with reference to the embodiments.

[0173] This embodiment provides an electrode active material, taking Li5FeO4@C as an example, and the specific preparation method is as follows:

[0174] Mixing: Fe2O3@C with a carbon content of 25% was selected as the precursor of the electrode active material. The Dv50 of Fe2O3@C is 10 nm and the powder resistivity is 1.02 Ω·cm. In addition, lithium hydroxide (LiOH·H2O) was selected as the A source and added to the mechanical fusion machine at a metal molar ratio of Li:Fe of 5.1:1. The mixture was mixed by mechanical fusion at a speed of 300 rpm for 6 hours.

[0175] Sintering: The mixed raw materials are heated to a sintering temperature of 600℃ at a rate of 3℃ / min under nitrogen atmosphere and sintered for 10 hours. Then the mixture is allowed to cool naturally to obtain the product.

[0176] Crushing and classifying: After crushing, classifying and sieving the product, carbon-coated metal oxide particles (Li5FeO4@C) can be obtained.

[0177] Example 24

[0178] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 23, except that the Dv50 of Fe2O3@C in Example 23 is changed to 20nm and the powder resistivity is 0.56Ω·cm.

[0179] Example 25

[0180] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 23, except that the Dv50 of Fe2O3@C in Example 23 is changed to 60nm and the powder resistivity is 0.22Ω·cm.

[0181] Example 26

[0182] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 25, except that the Dv50 of Fe2O3@C in Example 25 is changed to 100nm and the powder resistivity is 3.58Ω·cm.

[0183] Example 27

[0184] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 25, except that the Dv50 of Fe2O3@C in Example 25 is changed to 200nm and the powder resistivity is 8.32Ω·cm.

[0185] Example 28

[0186] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 25, except that the Fe2O3@C carbon content in Example 25 is changed to 10%, and the powder resistivity is 15.34 Ω·cm.

[0187] Example 29

[0188] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 25, except that the Fe2O3@C carbon content in Example 25 is changed to 20%, and the powder resistivity is 10.13 Ω·cm.

[0189] Example 30

[0190] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 25, except that the Fe2O3@C carbon content in Example 25 is changed to 30%, and the powder resistivity is 0.48Ω·cm.

[0191] Example 31

[0192] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 25, except that the Fe2O3@C carbon content in Example 25 is changed to 40%, and the powder resistivity is 0.71Ω·cm.

[0193] Example 32

[0194] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 25, except that the sintering temperature in Example 25 is changed to 500℃.

[0195] Example 33

[0196] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 25, except that the sintering temperature in Example 25 is changed to 550°C.

[0197] Example 34

[0198] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 25, except that the sintering temperature in Example 25 is changed to 650°C.

[0199] Example 35

[0200] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 25, except that the sintering temperature in Example 25 is changed to 700℃.

[0201] Example 36

[0202] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 25, except that the sintering time in Example 25 is changed to 4 hours.

[0203] Example 37

[0204] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 25, except that the sintering time in Example 25 is changed to 8h.

[0205] Example 38

[0206] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 25, except that the sintering time in Example 25 is changed to 12h.

[0207] Example 39

[0208] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 25, except that the sintering time in Example 25 is changed to 20h.

[0209] Example 40

[0210] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 25, except that the carbon source in Example 25 is replaced by carbon nanotubes instead of carbon black, and the powder resistivity of the precursor Fe2O3@CNTs is 0.24Ω·cm.

[0211] Example 41

[0212] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 25, except that the carbon source in Example 25 is replaced with graphite instead of carbon black, and the resistivity of the precursor Fe2O3@Gr powder is 0.23Ω·cm.

[0213] Example 42

[0214] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 25, except that Fe2O3@C in Example 25 is replaced with NiO@C, the Dv50 of NiO@C is 58nm, the powder resistivity is 0.21Ω·cm, the carbon content of NiO@C is changed to 23%, and the sintering temperature is changed to 620℃.

[0215] Example 43

[0216] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 25, except that Fe2O3@C in Example 25 is replaced with CuO@C, CuO@C has a Dv50 of 62nm and a powder resistivity of 0.25Ω·cm, the carbon content of CuO@C is changed to 22%, and the sintering temperature is changed to 590℃.

[0217] Example 44

[0218] This embodiment provides an electrode active material, the preparation method of which is roughly the same as that of Example 25, except that Fe2O3@C in Example 25 is replaced with Co3O4@C, the Dv50 of Co3O4@C is 61nm, the powder resistivity is 0.19Ω·cm, the carbon content of Co3O4@C is changed to 24%, and the sintering temperature is changed to 610℃.

[0219] Comparative Example 7

[0220] This comparative example provides an electrode active material, taking Li5FeO4@C as an example, and the specific preparation method is as follows:

[0221] Mixing: Fe2O3@C with a carbon content of 1% was selected as the precursor of the electrode active material. The Dv50 of Fe2O3@C is 320nm and the powder resistivity is 25.16Ω·cm. In addition, lithium hydroxide (LiOH·H2O) was selected as the A source and added to the mechanical fusion machine at a metal molar ratio of Li:Fe of 5.1:1. The mixture was mixed by mechanical fusion at a speed of 300 rpm for 6 hours.

[0222] Sintering: The mixed raw materials are heated to a sintering temperature of 600℃ at a rate of 3℃ / min under nitrogen atmosphere and sintered for 10 hours. Then the mixture is allowed to cool naturally to obtain the product.

[0223] Crushing and classifying: After crushing, classifying and sieving the product, carbon-coated metal oxide particles (Li5FeO4@C) can be obtained.

[0224] Comparative Example 8

[0225] This comparative example provides an electrode active material, the preparation method of which is roughly the same as that of comparative example 7, except that: the Dv50 of Fe2O3@C in comparative example 7 is changed to 420 nm, the powder resistivity is 36.78 Ω·cm, the carbon content in Fe2O3@C is 5%, the sintering temperature is changed to 750℃, and other operating procedures remain unchanged.

[0226] Comparative Example 9

[0227] This comparative example provides an electrode active material, the preparation method of which is roughly the same as that of comparative example 7, except that: the Dv50 of Fe2O3@C in comparative example 7 is changed to 250 nm, the powder resistivity is 18.36 Ω·cm, the carbon content in Fe2O3@C is 25%, the sintering temperature is changed to 450℃, the sintering time is changed to 2 h, and other operation procedures remain unchanged.

[0228] Comparative Example 10

[0229] This comparative example provides an electrode active material, the preparation method of which is roughly the same as that of comparative example 7, except that: the Dv50 of Fe2O3@C in comparative example 7 is changed to 350 nm, the powder resistivity is 28.74 Ω·cm, the carbon content in Fe2O3@C is 50%, the sintering temperature is changed to 800℃, the sintering time is changed to 22 h, and other operating procedures remain unchanged.

[0230] Comparative Example 11

[0231] This comparative example provides an electrode active material, the preparation method of which is roughly the same as that of comparative example 7, except that: Fe2O3 is prepared by the steps of comparative example 5, the Dv50 of Fe2O3 is 2500 nm, the powder resistivity is 68201.39 Ω·cm, Fe2O3 is used as the precursor of the electrode active material, and other operation procedures are consistent with those of comparative example 7, and Li5FeO4 is directly used as the electrode active material.

[0232] Comparative Example 12

[0233] This comparative example provides an electrode active material whose preparation method is roughly the same as that of comparative example 7, except that: Fe2O3 / C is prepared by the steps of comparative example 6, the mass of carbon black is 25% of the mass of Fe2O3, the Dv50 of Fe2O3 / C is 2600 nm, and the powder resistivity is 2310.23 Ω·cm. This is used as the precursor of the electrode active material, and Li5FeO4 is prepared by sintering using the process of comparative example 7. Other operation processes remain unchanged.

[0234] The relevant parameters of the carbon-coated metal oxide particles in Examples 23-44 and Comparative Examples 7-12 are shown in Table 2 below.

[0235] Table 2: Reaction parameters of Examples 23-44 and Comparative Examples 7-12

[0236]

[0237] Test methods

[0238] Median particle size Dv50: determined using a Malvern Mastersizer 2000E laser particle size analyzer according to GB / T 19077-2016 Particle size distribution laser diffraction method.

[0239] Carbon content testing: A carbon content analyzer, model HCS-140, was used to test the carbon content in the powder according to the determination of total carbon and sulfur content of steel using the infrared absorption method after combustion in a high-frequency induction furnace (conventional method) GBT20123-2006.

[0240] Powder resistivity test: Dry the powder of carbon composite oxide particles or carbon-coated metal oxide particles, weigh an appropriate amount of powder, and then use a powder resistivity tester, model ST2722 digital four-probe instrument, to determine the powder resistivity of the sample according to GB / T 30835-2014 "Carbon Composite Lithium Iron Phosphate Cathode Material for Lithium-ion Batteries".

[0241] Initial charge capacity test of carbon-coated metal oxide particles: Carbon-coated metal oxide particles, conductive carbon black, and binder polyvinylidene fluoride (PVDF) were dispersed in N-methylpyrrolidone (NMP) solvent at a mass ratio of 80:10:10 and thoroughly mixed to obtain a positive electrode slurry. The positive electrode slurry was coated onto one surface of a positive electrode current collector aluminum foil, dried, and cold-pressed to obtain a positive electrode sheet. Ethyl carbonate (EC) and ethyl methyl carbonate (EMC) were mixed thoroughly at a mass ratio of 30:70 to obtain an organic solvent; lithium salt LiPF6 was then dissolved in the above organic solvent and mixed thoroughly to obtain an electrolyte, wherein the concentration of LiPF6 was 1 mol / L. A lithium sheet was used as the counter electrode and assembled with the positive electrode sheet to form a coin cell. The coin cell was charged at a constant current rate of 0.1C to 4.25V, allowed to stand for 5 minutes, and the charge capacity of the coin cell was recorded at this time. The initial charge capacity is calculated by dividing the battery's charging capacity by the mass of the carbon-coated metal oxide particles.

[0242] Test Results

[0243] The morphology of the prepared carbon composite oxide particles was characterized by scanning electron microscopy (SEM). The characterization results are shown in the figure. Figure 1 The study revealed a large number of uniformly shaped, compact, and evenly distributed particles. Transmission electron microscopy (TEM) was used to further characterize the morphology of the carbon-composite oxide particles; the results are shown below. Figure 2 As can be seen from the contrast in the image, the oxide particles are uniformly coated on the carbon, and the particle size is uniform with no obvious agglomeration. X-ray diffraction (XRD) was used to analyze the structure of the carbon-composite oxide particles prepared in Example 3, and the results are shown in [Figure 1]. Figure 3 Crystal form comparison shows that the synthesized product is Fe2O3@C.

[0244] The powder resistivity and median particle size of the carbon composite oxide particles in Examples 1-22 and Comparative Examples 1-6 are shown in Table 3 below.

[0245] Table 3: Test results of carbon composite oxide particles prepared in Examples 1-22 and Comparative Examples 1-6

[0246]

[0247] As can be seen from the comparison of Examples 1-22 and Comparative Examples 1-4 with Comparative Examples 5 and 6, the carbon composite oxide particles disclosed in this application have low resistivity, suitable median particle size and carbon content.

[0248] As can be seen from the comparison of Examples 1-5 and Comparative Examples 1 and 2, adjusting the pH value of the alkaline mixture can regulate the powder resistivity and median particle size of the carbon composite oxide particles. An appropriate pH value of the alkaline mixture is beneficial for preparing carbon composite oxide particles with low powder resistivity and suitable median particle size. As can be seen from Examples 6-13, adjusting the reaction temperature or reaction time of the precipitation reaction can regulate the powder resistivity and median particle size of the carbon composite oxide particles. An appropriate reaction temperature and reaction time of the precipitation reaction are beneficial for preparing carbon composite oxide particles with low powder resistivity and suitable median particle size. As can be seen from the comparison of Examples 14-17 and Comparative Examples 3 and 4, adjusting the carbon content of the carbon composite oxide particles can regulate the powder resistivity and median particle size of the carbon composite oxide particles. The median particle size Dv50 and powder resistivity of the carbon composite oxide particles first decrease and then increase with increasing carbon content.

[0249] As can be seen from Examples 18-19, the method for preparing carbon composite oxide particles disclosed in this application is applicable to various carbon sources such as carbon nanotubes and graphite.

[0250] As can be seen from Examples 20-22, the method for preparing carbon composite oxide particles disclosed in this application is applicable to the preparation of various carbon composite oxides such as carbon composite copper oxide and carbon composite nickel oxide. The prepared products all have low powder resistivity and suitable median particle size.

[0251] The morphology of carbon-coated metal oxide particles was analyzed using transmission electron microscopy (TEM). The results are shown in [Figure number missing]. Figure 4 As can be seen from the contrast in the image, the active material particles are uniformly coated in carbon, with a particle size at the nanometer level, and no obvious agglomeration has occurred. X-ray diffraction (XRD) was used to test the carbon-coated metal oxide particles prepared according to the method of Example 25, and the test results are shown in [Figure 25]. Figure 5 Crystal form comparison revealed that the synthesized product is a carbon-coated lithium-rich iron oxide, denoted as Li5FeO4@C. The first charging curve of the battery assembled using this as the electrode material is shown below. Figure 6 This is used to calculate the initial charge capacity of the battery.

[0252] The test results of the carbon-coated metal oxide particles of Examples 23-44 and Comparative Examples 7-12 are shown in Table 4 below.

[0253] Table 4: Test results of carbon-coated metal oxide particles prepared in Examples 23-44 and Comparative Examples 7-12

[0254]

[0255]

[0256] By comparing Examples 23-44 and Comparative Examples 7-12, it can be seen that carbon-coated metal oxide particles prepared by sintering under certain conditions using the carbon composite oxide particles synthesized above with uniform particle size distribution, low powder resistivity and good dispersibility have low powder resistivity, suitable median particle size Dv50 and high charge capacity.

[0257] As can be seen from the comparison of Examples 23-27 and Comparative Examples 7-9, adjusting the median particle size Dv50 of the carbon-composite oxide particles can regulate the powder resistivity and median particle size of the carbon-coated metal oxide particles. An appropriate median particle size Dv50 of the carbon-composite oxide particles is beneficial for preparing carbon-coated metal oxide particles with low powder resistivity, suitable median particle size, and high specific capacity. As can be seen from Examples 28-31, adjusting the carbon content of the carbon-composite oxide particles can regulate the powder resistivity and median particle size of the carbon-coated metal oxide particles. An appropriate carbon content in the carbon-composite oxide particles is beneficial for preparing carbon-coated metal oxide particles with low powder resistivity and suitable median particle size, thereby improving the specific capacity of the battery. As can be seen from the comparison of Examples 32-39 and Comparative Examples 9-10, adjusting the sintering temperature and time can regulate the powder resistivity and median particle size of the carbon-coated metal oxide particles.

[0258] As can be seen from Examples 40-41, carbon composite oxides prepared from various carbon sources can be used to prepare carbon-coated metal oxide particles with low powder resistivity and high charge capacity.

[0259] As can be seen from Examples 42-44, the method for preparing carbon-coated metal oxide particles disclosed in this application is applicable to the preparation of various electrode active materials such as Li2NiO2@C, Li2CuO2@C, and Li6CoO4@C. The prepared products all have low powder resistivity, suitable median particle size, and high charge specific capacity, indicating that the preparation method is universal.

[0260] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. An electrode active material precursor, comprising carbon composite oxide particles, characterized in that, The oxide satisfies equation (1): M a O b (1) Wherein, element M is selected from one or more of Ni, Co, Fe, Mn, Zn, Mg, Cu, Mn, Mo, Ru, Ir, V, Nb, and Cr, a>0, b>0, and the powder resistivity of the carbon composite oxide particles is less than 100 Ω·cm. The median particle size Dv50 of the carbon composite oxide particles is 10~200 nm.

2. The electrode active material precursor according to claim 1, characterized in that, The median particle size Dv50 of the carbon composite oxide particles is 20~100nm.

3. The electrode active material precursor according to claim 1 or 2, characterized in that, The resistivity of the carbon composite oxide particles is less than 10 Ω·cm.

4. The electrode active material precursor according to any one of claims 1-3, characterized in that, The resistivity of the carbon composite oxide particles is less than 1 Ω·cm.

5. The electrode active material precursor according to any one of claims 1-4, characterized in that, The mass content of carbon in the carbon composite oxide particles is 10% to 40%.

6. The electrode active material precursor according to any one of claims 1-5, characterized in that, The carbon element in the carbon composite oxide particles has a mass content of 20% to 30%.

7. A method for preparing an electrode active material precursor, characterized in that, The method includes the following steps: The carbon source is dispersed in an aqueous solution containing M ions to obtain a mixture; Adjust the pH of the mixture to alkaline to obtain an alkaline mixture; The alkaline mixture undergoes a precipitation reaction to obtain a precipitate; The precipitate was separated and washed to obtain the precursor. The precursor is dehydrated and dried to prepare an electrode active material precursor; the electrode active material precursor comprises carbon composite oxide particles, and the oxide satisfies formula (1): M a O b (1) Wherein, element M is selected from one or more of Ni, Co, Fe, Mn, Zn, Mg, Cu, Mn, Mo, Ru, Ir, V, Nb, and Cr, a>0, b>0, and the powder resistivity of the carbon composite oxide particles is less than 100 Ω·cm. The median particle size Dv50 of the carbon composite oxide particles is 10~200 nm.

8. The method for preparing electrode active material precursors according to claim 7, characterized in that, The pH value of the alkaline mixture is in the range of 9 to 13.

9. The method for preparing an electrode active material precursor according to claim 7 or 8, characterized in that, The pH value of the alkaline mixture is in the range of 10 to 12.

10. The method for preparing an electrode active material precursor according to any one of claims 7-9, characterized in that, The reaction time for the precipitation reaction is in the range of 4 to 15 hours.

11. The method for preparing an electrode active material precursor according to claim 10, characterized in that, The reaction time for the precipitation reaction is in the range of 6 to 12 hours.

12. The method for preparing an electrode active material precursor according to any one of claims 7-11, characterized in that, The reaction temperature of the precipitation reaction is in the range of 30~80℃.

13. The method for preparing an electrode active material precursor according to claim 12, characterized in that, The reaction temperature of the precipitation reaction is in the range of 40~60℃.

14. The method for preparing an electrode active material precursor according to any one of claims 7-13, characterized in that, Before adjusting the pH of the mixture to alkaline, a weak alkaline solution is added to the mixture.

15. The method for preparing an electrode active material precursor according to claim 14, characterized in that, The weak alkaline solution is selected from one or more of ammonia water, ammonium bicarbonate aqueous solution, ammonium carbonate aqueous solution, sodium carbonate aqueous solution, and sodium bicarbonate aqueous solution.

16. The method for preparing an electrode active material precursor according to any one of claims 7-15, characterized in that, The carbon source is selected from one or more of carbon black, acetylene black, Ketjen black, carbon nanotubes, graphene, graphite, carbon fiber, and carbon microspheres.

17. The method for preparing an electrode active material precursor according to any one of claims 7-16, characterized in that, The aqueous solution containing M ions is prepared by dissolving one or more of the following: sulfate, nitrate, oxalate, and halide containing the M element in water.

18. The method for preparing an electrode active material precursor according to any one of claims 7-17, characterized in that, The precursor is dried at 100-200°C for 6-20 hours to obtain the electrode active material precursor.

19. An electrode active material, characterized in that, It is prepared using the electrode active material precursor according to any one of claims 1-6 as raw material.

20. A battery, characterized in that, Includes the electrode active material as described in claim 19.

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