Lithium-containing carbonate precursor, preparation method thereof, lithium-containing oxide precursor and positive electrode material

Abstract

The invention provides a lithium-containing carbonate precursor and a preparation method thereof, a lithium-containing oxide precursor and a positive electrode material, the lithium-containing carbonate precursor comprises spheroidic secondary particles, and the secondary particles comprise a plurality of sheet-shaped primary particles. According to the lithium-containing carbonate precursor disclosed by the embodiment of the invention, the lithium element is uniformly introduced into the carbonate precursor through front-end lithium doping, so that the lithium element is uniformly distributed, and the problem of impurity phase generation caused by excessive or insufficient local lithium in a later sintering process in the prior art can be avoided; meanwhile, uniform distribution of the lithium element is beneficial to formation of a complete layered result, mixed arrangement of cations is reduced, and the stability of a crystal structure is improved; in addition, the lithium element in the lithium-containing carbonate precursor is uniformly distributed, so that the diffusion rate of lithium ions in the material can be improved, the obstruction of ion migration is reduced, and the lithium-containing carbonate precursor has relatively good rate capability and cycle performance.

Description

Technical Field

[0001] This application belongs to the field of battery cathode material technology, and particularly relates to a lithium carbonate precursor and its preparation method, a lithium oxide precursor and cathode material. Background Technology

[0002] Lithium-ion batteries, with their outstanding advantages such as high energy density, long cycle life, and low self-discharge rate, are widely used in portable electronic devices, electric vehicles, and large-scale energy storage. With the rapid development of these applications, the performance requirements for lithium-ion batteries are also increasing, especially in high-power applications such as the rapid acceleration, hill climbing, and instantaneous high-power discharge of electric vehicles, which place stringent demands on the battery's high-power performance.

[0003] As a key component of lithium-ion batteries, the cathode material is a core component that determines critical parameters such as battery energy density, cycle life, and safety performance. The final performance of the cathode material is primarily inherited from the precursor. Therefore, developing high-performance cathode material precursors has become a research hotspot and key direction in the current lithium-ion battery field. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a lithium carbonate precursor and its preparation method, a lithium oxide precursor, and a cathode material, which can improve the lithium-ion transport rate and enhance the charge / discharge efficiency and rate performance of the battery.

[0005] In a first aspect, embodiments of this application provide a lithium carbonate precursor, which includes spherical secondary particles, the surface of which includes a plurality of plate-like primary particles.

[0006] According to an embodiment of the first aspect of this application, the plate-like primary particles on the surface of the secondary particles are arranged in a disordered manner.

[0007] According to an embodiment of the first aspect of this application, the chemical formula of the lithium carbonate precursor is Li x MeB z Where 0.6≤x≤2.2, 1.2≤z≤2.2;

[0008] Me includes Mn and Ni, and optionally, Me also includes one or more of Co, Al, Na, K, Ca, Sr, Y, Ti, Zr, Nb, Sb, Fe, Cu, and Zn;

[0009] B includes CO3, and optionally, B also includes one or more of OH, Cl, NO3, SO4, HCO3, H2PO4, HPO4, and PO4.

[0010] According to an embodiment of the first aspect of this application, the lithium carbonate precursor satisfies at least one of the following conditions:

[0011] A. The width of the primary particles is 0.1μm to 1.5μm, and the thickness is ≤50nm;

[0012] B. Precursor volume distribution particle size D V 50 is 2.0μm~15.0μm, optional, D V 50 ranges from 4.0 μm to 12.0 μm;

[0013] C. The particle size distribution of the precursor ranges from 0.3 to 1.6.

[0014] D. The specific surface area of ​​the precursor is 30 m². 2 / g~100m 2 / g;

[0015] E. The tap density of the precursor is 1.0 g / m³. 3 ~2.0g / m 3 ;

[0016] F. The sphericity of the precursor is 80%–100%, and can be selected as 85%–90%;

[0017] G. Precursor Li x MeB z In the equation, 0.9 ≤ x ≤ 1.5.

[0018] Secondly, embodiments of this application provide a method for preparing a lithium carbonate precursor, comprising: mixing a solution containing Li and Me elements with a carbonate solution under an inert gas atmosphere to carry out a co-precipitation reaction to obtain a lithium carbonate precursor.

[0019] According to an embodiment of the second aspect of this application, the preparation method satisfies at least one of the following conditions:

[0020] (1) The preparation method further includes a solution preparation step, wherein the solution preparation includes preparing lithium salt solution, Me salt solution and carbonate solution respectively; and / or the solution preparation includes preparing solutions containing lithium salt and Me salt and carbonate solution respectively;

[0021] (2) The pH value at which the coprecipitation reaction takes place is 8.6–9.6;

[0022] (3) The temperature for the coprecipitation reaction is 45–65℃;

[0023] (4) The molar ratio of Li ions, Me ions and carbonate ions during the coprecipitation reaction is 1:(1.05~2.5):(1.5~3.0);

[0024] (5) The preparation method also includes post-treatment of the precipitate; optionally, the post-treatment includes solid-liquid separation, washing, drying and demagnetization.

[0025] According to an embodiment of the second aspect of this application, the preparation method satisfies at least one of the following conditions:

[0026] a. The lithium salt is selected from one or more of lithium sulfate, lithium nitrate, or lithium chloride;

[0027] b. Me salts include nickel salts and manganese salts. Optionally, Me salts may also include one or more of the following: Co salts, Al salts, Na salts, K salts, Ca salts, Sr salts, Y salts, Ti salts, Zr salts, Nb salts, Sb salts, Fe salts, Cu salts, and Zn salts. Optionally, the nickel salts may be selected from one or more of the following: sulfates, nickel nitrates, or nickel chlorides. Optionally, the manganese salts may be selected from one or more of the following: manganese sulfates, manganese nitrates, or manganese chlorides.

[0028] c. The carbonate is selected from one or more of lithium carbonate, sodium carbonate, or potassium carbonate;

[0029] d. The concentration of the carbonate solution is 2.0 mol / L to 5.0 mol / L;

[0030] e. The lithium ion concentration in the lithium salt solution is 2 mol / L to 5 mol / L;

[0031] f. The concentration of Me ions in the Me salt solution is 1 mol / L to 3 mol / L;

[0032] g. The concentration of lithium ions in the solution containing lithium salt and Me salt is 2 mol / L to 5 mol / L, and the concentration of Me ions is 1 mol / L to 3 mol / L;

[0033] h. Mixing a solution containing Li and Me elements with a carbonate solution involves mixing a lithium salt solution, a Me salt solution, and a carbonate solution, or mixing a solution containing lithium and Me salts with a carbonate solution.

[0034] Thirdly, embodiments of this application provide a lithium oxide precursor, the chemical formula of which is Li a MtC b M comprises nickel and manganese, C comprises O, 0.6≤a≤2.2, 1.2≤b≤2.2; optionally, M further comprises one or more of Co, Al, Na, K, Ca, Sr, Y, Ti, Zr, Nb, Sb, Fe, Cu, and Zn, optionally, where 0.9≤a≤1.5.

[0035] According to an embodiment of the third aspect of this application, a lithium oxide precursor is prepared by pre-sintering from the lithium carbonate precursor in the first aspect of this application or the lithium carbonate precursor prepared by the preparation method in the second aspect of this application. Optionally, the pre-sintering temperature is 500-800°C, and further optionally, the pre-sintering heating rate is 1-3°C / min, and the pre-sintering time is 8-15h.

[0036] Fourthly, embodiments of this application provide a cathode material, which is prepared by sintering the lithium carbonate precursor in the first aspect of this application, or the lithium carbonate precursor prepared by the preparation method in the second aspect of this application, or the lithium oxide precursor in the third aspect of this application.

[0037] Fifthly, embodiments of this application provide a lithium-ion battery comprising the positive electrode material described in the fourth aspect of this application.

[0038] Sixthly, this application provides an electrical device, including the lithium-ion battery described in the fifth aspect of this application.

[0039] In this embodiment, the lithium-containing carbonate precursor introduces lithium uniformly into the carbonate precursor through front-end lithium doping, resulting in a uniform distribution of lithium. This avoids the problem of impurity phase formation due to local lithium excess or deficiency during the later sintering process. At the same time, the uniform distribution of lithium helps to form a complete layered structure, reduces cation mixing, and improves the stability of the crystal structure. In addition, the uniform distribution of lithium can improve the diffusion rate of lithium ions in the material and reduce the hindrance to ion migration, thus enabling the material to have better rate performance and cycle performance.

[0040] Lithium carbonate precursors can be sintered directly, eliminating the lithium mixing process and avoiding errors caused by traditional batching / mixing processes. The resulting cathode material has low process cost and good product consistency.

[0041] The lithium carbonate precursor comprises near-spherical secondary particles, the surface of which includes multiple plate-like primary particles. The near-spherical shape of the secondary particles facilitates the formation of a complete single-crystal structure, reduces crystal defects, and results in a more uniform stress distribution within the particles. The plate-like primary particles are more likely to form single-crystal particles during high-temperature sintering, increasing the crystallinity of the cathode material. After sintering, the cathode material exhibits low surface microparticle density, a complete layered structure, and low cation mixing, improving crystal structure stability and enhancing the capacity utilization and cycle performance of the cathode material. The plate-like primary particles on the surface of the secondary particles increase the specific surface area of ​​the precursor during sintering, allowing for more sufficient interfacial contact and providing more active sites for solid-phase reactions, accelerating the reaction mass transfer rate, and thus improving sintering efficiency. Simultaneously, interfacial contact can lower the required sintering temperature, reduce sintering energy consumption, and help reduce production costs. Attached Figure Description

[0042] Figure 1 This is a SEM image of the lithium carbonate precursor provided in Example 1 of this application;

[0043] Figure 2 The XRD pattern of the cathode material provided in Example 1 of this application;

[0044] Figure 3 This is a SEM image of the lithium carbonate precursor provided in Example 2 of this application;

[0045] Figure 4 This is a SEM image of the lithium carbonate precursor provided in Example 3 of this application;

[0046] Figure 5 This is a SEM image of the lithium carbonate precursor provided in Example 4 of this application;

[0047] Figure 6 This is a SEM image of the lithium carbonate precursor provided in Example 5 of this application;

[0048] Figure 7 This is a SEM image of the lithium carbonate precursor provided in Example 6 of this application;

[0049] Figure 8 This is a SEM image of the lithium carbonate precursor provided in Example 7 of this application;

[0050] Figure 9 This is a SEM image of the cathode material precursor provided in Comparative Example 1 of this application;

[0051] Figure 10 This is a SEM image of the cathode material precursor provided in Comparative Example 2 of this application;

[0052] Figure 11 This is a SEM image of the cathode material precursor provided in Comparative Example 3 of this application. Detailed Implementation

[0053] To make the purpose, technical solution, and beneficial technical effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the embodiments described in this specification are merely for explaining this application and are not intended to limit it.

[0054] For simplicity, this application only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form a range not explicitly stated; and any lower limit can be combined with other lower limits to form a range not explicitly stated, just as any upper limit can be combined with any other upper limit to form a range not explicitly stated. Furthermore, although not explicitly stated, every point or individual value between the endpoints of the range is included within that range. Therefore, each point or individual value can be used as its own lower or upper limit and combined with any other point or individual value or with other lower or upper limits to form a range not explicitly stated.

[0055] As used in this article:

[0056] In the description of this application, it should be noted that, unless otherwise stated, "above" and "below" include the stated number, and "multiple" in "one or more" means two or more.

[0057] "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0058] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0059] The word "and / or" is used to indicate that one or both of the described situations may occur; for example, A and / or B includes (A and B) and (A or B). It should be clarified that descriptions such as "thin" in this application specifically refer to the morphological characteristics of the corresponding structure in the cathode material precursor and should not be construed as specific quantifications.

[0060] In this application, particle size Dv50 and average particle size have the same meaning, referring to the particle size corresponding to the cumulative particle size distribution percentage of the lithium carbonate precursor reaching 50%.

[0061] In this application, the particle size distribution span is a parameter used to describe the breadth of the particle size distribution in a particle group. Its calculation formula is based on the cumulative distribution particle size, and is as follows: Particle size distribution span = (Dv90 - Dv10) / Dv50; where: Dv10: refers to the particle size at which 10% of the particles are smaller than this diameter (i.e., the particle size corresponding to 10% of the cumulative volume); Dv50: also known as the median particle size, refers to the particle size at which 50% of the particles are smaller than this diameter (the particle size corresponding to 50% of the cumulative volume); Dv90: refers to the particle size at which 90% of the particles are smaller than this diameter (the particle size corresponding to 90% of the cumulative volume). The specific values ​​of Dv10, Dv50, and Dv90 can be measured using a laser particle size analyzer.

[0062] In this application, quasi-spherical is used to describe the shape of secondary granularity, and quasi-spherical is a general term for elliptical or circular bodies of revolution.

[0063] In this application, the sphericity calculation method is as follows: using a profile (CP) image, the major axis and minor axis are determined. The major axis is the longest distance between any two points on the outer perimeter of the CP image, and the minor axis is the longest distance perpendicular to the major axis. Sphericity = minor axis / major axis.

[0064] In this application, the method for calculating the length and thickness of the primary particles is as follows: the magnification of the scanning electron microscope (SEM) is adjusted until 1-3 complete images of the secondary particles of the cathode material precursor appear in the view and an SEM image is taken. The longest axis of the primary particle in the SEM image is defined as the major axis, and the longest axis that intersects the major axis perpendicularly is defined as the thickness. Multiple primary particles (e.g., 5, 10, 15 or 20) are selected and the length of the major axis and the length of the thickness of each primary particle are measured respectively to calculate the length and thickness of the primary particles.

[0065] Therefore, embodiments of this application provide a lithium carbonate precursor and its preparation method, a lithium oxide precursor and a cathode material, which have good rate performance and cycle performance.

[0066] In a first aspect, embodiments of this application provide a lithium carbonate precursor, which includes spherical secondary particles, the surface of which includes a plurality of plate-like primary particles.

[0067] By simultaneously introducing lithium during the co-precipitation process, a uniform distribution of lithium in the precursor is achieved. This not only avoids the problem of impurity phases caused by localized lithium excess or deficiency during later sintering, but also helps to form a complete layered structure, reduces cation mixing, and improves the stability of the crystal structure. Simultaneously, the uniform lithium distribution significantly enhances the lithium-ion diffusion rate and reduces migration obstacles, resulting in excellent rate performance and cycle performance. This precursor can be directly sintered, simplifying the process, eliminating the traditional lithium mixing step, avoiding batching errors, reducing production costs, and improving product consistency. The plate-like primary particles on its surface increase the specific surface area during sintering, providing more sufficient interfacial contact and more active sites, accelerating the mass transfer rate, thereby improving sintering efficiency, shortening sintering time, and reducing sintering temperature and energy consumption. Furthermore, the plate-like structure is more likely to form highly crystalline, low-cation mixing complete single-crystal particles at high temperatures, while the near-spherical secondary particles help to form a single-crystal structure with uniform internal stress and fewer defects, jointly promoting the capacity utilization and cycle stability of the cathode material. The spherical structure also has good fluidity and high packing density, which facilitates subsequent electrode processing, improves electrode consistency, and thus enhances the overall performance stability of the battery.

[0068] In some embodiments, the primary particles on the surface of the secondary particles are arranged in a disordered manner.

[0069] The disordered arrangement of primary particles on the surface of secondary particles can optimize the lithium-ion diffusion path. The three-dimensional interconnected porous network formed by the disordered arrangement breaks the directional diffusion limitations that may exist in ordered stacking, allowing lithium ions to migrate from multiple dimensions during charging and discharging, reducing diffusion dead zones. The larger buffer space of the disordered structure can alleviate the volume shrinkage stress during sintering, reduce particle cracking, and improve product yield.

[0070] In some embodiments, the chemical formula of the lithium carbonate precursor is Li x MeB z Where 0.6≤x≤2.2, 1.2≤z≤2.2, Me includes Mn and Ni, and optionally, Me also includes one or more of Co, Al, Na, K, Ca, Sr, Y, Ti, Zr, Nb, Sb, Fe, Cu, and Zn;

[0071] B includes CO3.

[0072] In some embodiments, B further includes one or more of OH, Cl, NO3, SO4, HCO3, H2PO4, HPO4, and PO4.

[0073] In this embodiment of the application, Me is [Me1] b1 Me2 b2 Me3 b3...Men bn ], where Me1, Me2, Me3...Men are all different and are independently selected from one of Co, Al, Na, K, Ca, Sr, Y, Ti, Zr, Nb, Sb, Fe, Cu, Zn, and b1, b2, b3...bn are the same or different, and b1+b2+b3+...+bn=1.

[0074] In the embodiments of this application, Me in the lithium carbonate precursor may include only Mn and Ni elements, or it may include one or more of Co, Al, Na, K, Ca, Sr, Y, Ti, Zr, Nb, Sb, Fe, Cu, and Zn in addition to Mn and Ni elements.

[0075] For example, Me includes Mn, Ni and Co elements; or Me includes Mn, Ni, Co and Al elements; or Me includes Mn, Ni, Co and Ti elements; or Me includes Mn, Ni, Co, Al and Ti elements. The embodiments of this application will not be listed one by one.

[0076] For example, the value of x can be any value among 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, and 2.2, or a range between any two.

[0077] In some embodiments, 0.9 ≤ x ≤ 1.5.

[0078] For example, the value of z can be any value among 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1 and 2.2 or a range between any two.

[0079] In this embodiment, the chemical formula Li x MeB z The values ​​of x and z in the formula can maintain the valence equilibrium of the chemical formula.

[0080] In some embodiments, the width of the primary particles on the surface of the secondary particles is 0.1 μm to 1.5 μm.

[0081] For example, the width of the primary particle is any value or a range between 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, and 1.5 μm.

[0082] In some embodiments, the thickness of the primary particles on the surface of the secondary particles is ≤50nm.

[0083] For example, the thickness of a primary particle is <10nm, 10nm, 20nm, 22nm, 24nm, 25nm, 26nm, 28nm, 30nm, 32nm, 34nm, 35nm, 36nm, 38nm, 40nm, 45nm, 50nm or less than or equal to 50nm or any value between both.

[0084] In some embodiments, the precursor's volume distribution particle size D V 50 ranges from 2.0μm to 15.0μm.

[0085] For example, the volumetric particle size D of the precursor V 50 is any value among 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, and 15μm, or a range between any two. Optionally, the precursor's volumetric particle size D... V 50 ranges from 4.0μm to 12.0μm.

[0086] In some embodiments, the particle size distribution of the precursor spans from 0.3 to 1.6.

[0087] For example, the particle size distribution of the precursor spans any value from 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5 and 1.6 or a range between any two.

[0088] In some embodiments, the specific surface area of ​​the precursor is 30 m². 2 / g~100m 2 / g.

[0089] A larger specific surface area means that the precursor particles have more surface active sites, which can promote atomic diffusion and migration during sintering. The specific surface area of ​​the pre-lithium-intercalated cathode material precursor in the embodiments of this application is within the above range, which provides favorable conditions for the precursor to form a single-crystal cathode material in the subsequent sintering process. The single-crystal cathode material has excellent cycle stability and structural stability, which can significantly improve the overall performance of lithium-ion batteries.

[0090] For example, the specific surface area of ​​the precursor is 30 m². 2 / g、35m 2 / g、40m 2 / g、45m 2 / g, 50m 2 / g、55m2 / g、60m 2 / g、65m 2 / g、70m 2 / g、75m 2 / g、80m 2 / g、85m 2 / g、90m 2 / g、95m 2 / g and 100m 2 Any value in / g or any range between the two.

[0091] In some embodiments, the tap density of the precursor is 1.0 g / m³. 3 ~2.0g / m 3 .

[0092] Tap density reflects the compactness of a material under certain vibration conditions; a higher tap density means that more active material can be accommodated per unit volume. In the embodiments of this application, the tap density of the precursor is between 1.0 and 2.0 g / m³. 3 This can effectively improve the volumetric energy density of the final cathode material.

[0093] For example, the tap density of the precursor is 1.0 g / m³. 3 1.1g / m 3 1.2g / m 3 1.3g / m 3 1.4g / m 3 1.5g / m 3 1.6g / m 3 1.7g / m 3 1.8g / m 3 1.9g / m 3 and 2.0g / m 3 The value can be any value in the range or any value between the two. Optionally, the tapped density is 1.0 to 1.21 g / m³. 3 .

[0094] In some embodiments, the sphericity of the precursor is 80% to 100%.

[0095] For example, the sphericity of the precursor is any value or a range between 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, and 100%.

[0096] Sphericity refers to the degree to which particles approximate a sphere; a higher sphericity indicates a closer approximation to a sphere. In the embodiments of this application, the sphericity of the precursor is 80% to 100%, meaning that the outer contour of the secondary particles of the precursor deviates little from that of a standard sphere, and the overall shape presents a regular, near-spherical form.

[0097] Sphericity within the aforementioned range allows precursor particles to be packed more tightly during assembly, reducing gaps between particles and increasing packing density. This helps to pack more cathode material into a battery casing of the same volume, thereby increasing the battery's energy density. Simultaneously, precursor particles with higher sphericity are more evenly distributed in the sintering furnace and heat more uniformly, avoiding localized temperature differences caused by irregular particle morphology. This ensures the uniformity of the crystal structure of the cathode material after sintering and reduces performance defects caused by poor localized sintering.

[0098] Preferably, the sphericity of the precursor is 85% to 90%.

[0099] The inventors of this application have noted that existing precursors typically require further mixing with a lithium source before sintering into cathode materials. The mixing method mainly relies on mechanical mixing, which carries the risk of uneven mixing, easily leading to localized lithium excess or deficiency, resulting in unstable material performance. Furthermore, the added lithium source generally has a large particle size of approximately 10 μm, which is detrimental to lithium-ion migration during the sintering reaction, resulting in poor sintering performance. Simultaneously, the existing ternary cathode material preparation process is lengthy and cumbersome, and the preparation methods still require improvement.

[0100] In view of this, in a second aspect, embodiments of this application provide a method for preparing a lithium carbonate precursor, comprising: mixing a solution containing Li and Me elements with a carbonate solution under an inert gas atmosphere to carry out a co-precipitation reaction to obtain a lithium carbonate precursor.

[0101] The preparation method of this application adopts a co-precipitation strategy to achieve uniform co-precipitation of lithium and Me elements in one step. Through the co-precipitation reaction, Li and Me elements are fully mixed in the solution and then precipitate together, avoiding the problem of uneven element distribution caused by subsequent batching / mixing processes in traditional processes. This ensures that the elements in the precursor are evenly distributed, laying the foundation for the subsequent preparation of high-performance cathode materials.

[0102] The preparation method of this application embodiment does not use complexing agents such as ammonia water in the precursor preparation process, does not generate ammonia nitrogen wastewater, has a simple process, is environmentally friendly, and is conducive to market promotion.

[0103] In the embodiments of this application, Me includes Mn and Ni.

[0104] In some embodiments, Me also includes one or more of Co, Al, Na, K, Ca, Sr, Y, Ti, Zr, Nb, Sb, Fe, Cu, and Zn.

[0105] By adjusting process parameters such as the ratio of each element in the solution containing Li and Me to the carbonate solution, reaction temperature, pH value, and stirring rate, the chemical composition, particle size, and particle morphology of the precursor can be controlled to meet the performance requirements of different cathode materials.

[0106] In some embodiments, the preparation method further includes a solution preparation step, wherein the solution preparation includes preparing a lithium salt solution, a Me salt solution and a carbonate solution respectively.

[0107] In some embodiments, the preparation method further includes a solution preparation step, wherein the solution preparation includes preparing solutions containing lithium salt and Me salt and a carbonate solution, respectively.

[0108] For example, lithium salt solutions and Me salt solutions can be prepared separately and placed in different containers; lithium salt solutions and Me salt solutions can also be prepared in the same container.

[0109] In some embodiments, the coprecipitation reaction is carried out at a pH of 8.6 to 9.6.

[0110] For example, the pH of the coprecipitation reaction is any value of 8.6, 8.7, 8.8, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5 or 9.6 or a range between any two.

[0111] In some embodiments, the temperature of the coprecipitation reaction is 45–65°C.

[0112] For example, the temperature of the coprecipitation reaction is any value or a range between any two of 45°C, 46°C, 47°C, 48°C, 49°C, 50°C, 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C, and 65°C.

[0113] In some embodiments, the molar ratio of Li ions, Me ions and carbonate ions during the coprecipitation reaction is 1:(1.05-2.5):(1.5-3.0).

[0114] For example, the molar ratio of Li ions, Me ions and carbonate ions in the coprecipitation reaction is 1:1.05:(1.5~3.0), 1:1.5:(1.5~3.0), 1:2:(1.5~3.0), 1:(1.05~2.5):1.5, 1:(1.05~2.5):2, 1:(1.05~2.5):2.5 or 1:(1.05~2.5):3.

[0115] In some embodiments, the preparation method further includes post-treatment of the precipitate.

[0116] In some embodiments, post-processing includes solid-liquid separation, washing, drying, and demagnetization.

[0117] For example, solid-liquid separation can be achieved through filtration.

[0118] For example, the washing process involves alternating between deionized water and ethanol for 3-5 times to ensure that the precipitate is thoroughly cleaned. The precipitate is then dried at 80-120°C for 12-24 hours to remove moisture and demagnetize, resulting in a lithium carbonate precursor.

[0119] In some embodiments, the lithium salt is selected from one or more of lithium sulfate, lithium nitrate, or lithium chloride.

[0120] In some embodiments, the Me salt comprises a nickel salt and a manganese salt.

[0121] Optionally, the nickel salt is selected from one or more of nickel sulfate, nickel nitrate, or nickel chloride.

[0122] For example, nickel salts include nickel nitrate (Ni(NO3)2·6H2O), nickel sulfate (NiSO4·6H2O), nickel chloride (NiCl2·6H2O), or nickel acetate (Ni(CH3COO)2·4H2O), etc.

[0123] Optionally, the manganese salt is selected from one or more of manganese sulfate, manganese nitrate, or manganese chloride. Exemplarily, the manganese salt includes manganese nitrate (Mn(NO3)2·4H2O), manganese sulfate (MnSO4·H2O, MnSO4·5H2O), manganese chloride (MnCl2·4H2O), etc.

[0124] In some embodiments, the Me salt further includes one or more of the following: Co salt, Al salt, Na salt, K salt, Ca salt, Sr salt, Y salt, Ti salt, Zr salt, Nb salt, Sb salt, Fe salt, Cu salt, and Zn salt.

[0125] Optionally, the Co salt is selected from one or more of cobalt nitrate, cobalt sulfate, and cobalt chloride.

[0126] For example, Co salts include cobalt nitrate (Co(NO3)2·6H2O), cobalt sulfate (CoSO4·7H2O), cobalt chloride (CoCl2·6H2O), etc.

[0127] In some embodiments, Co salt, Al salt, Na salt, K salt, Ca salt, Sr salt, Y salt, Ti salt, Zr salt, Nb salt, Sb salt, Fe salt, Cu salt, and Zn salt are soluble salts.

[0128] In some embodiments, the carbonate is selected from one or more of lithium carbonate, sodium carbonate, or potassium carbonate.

[0129] In some embodiments, the concentration of the carbonate solution is 2.0 mol / L to 5.0 mol / L.

[0130] For example, the concentration of the carbonate solution is any value or a range between any two of the following: 2.0 mol / L, 2.2 mol / L, 2.4 mol / L, 2.5 mol / L, 2.6 mol / L, 2.8 mol / L, 3.0 mol / L, 3.2 mol / L, 3.4 mol / L, 3.5 mol / L, 3.6 mol / L, 3.8 mol / L, 4.0 mol / L, 4.2 mol / L, 4.4 mol / L, 4.5 mol / L, 4.6 mol / L, 4.8 mol / L, and 5.0 mol / L.

[0131] In some embodiments, the lithium ion concentration in the lithium salt solution is 2 mol / L to 5 mol / L.

[0132] For example, the lithium ion concentration in the lithium salt solution is any value or a range between any two of the following: 2.0 mol / L, 2.2 mol / L, 2.4 mol / L, 2.5 mol / L, 2.6 mol / L, 2.8 mol / L, 3.0 mol / L, 3.2 mol / L, 3.4 mol / L, 3.5 mol / L, 3.6 mol / L, 3.8 mol / L, 4.0 mol / L, 4.2 mol / L, 4.4 mol / L, 4.5 mol / L, 4.6 mol / L, 4.8 mol / L, and 5.0 mol / L.

[0133] In some embodiments, the concentration of Me ions in the Me salt solution is 1 mol / L to 3 mol / L.

[0134] For example, the concentration of Me ions in the Me salt solution is any value or a range between any two of 1.0 mol / L, 1.2 mol / L, 1.4 mol / L, 1.5 mol / L, 1.6 mol / L, 1.8 mol / L, 2.0 mol / L, 2.2 mol / L, 2.4 mol / L, 2.5 mol / L, 2.6 mol / L, 2.8 mol / L, and 3.0 mol / L.

[0135] In some embodiments, the concentration of lithium ions in the solution containing lithium salt and Me salt is 2 mol / L to 5 mol / L, and the concentration of Me ions is 1 mol / L to 3 mol / L.

[0136] For example, the concentrations of lithium ions in solutions containing lithium salts and Me salts are 2.0 mol / L, 2.2 mol / L, 2.4 mol / L, 2.5 mol / L, 2.6 mol / L, 2.8 mol / L, 3.0 mol / L, 3.2 mol / L, 3.4 mol / L, 3.5 mol / L, 3.6 mol / L, 3.8 mol / L, 4.0 mol / L, 4.2 mol / L, 4.4 mol / L, 4.5 mol / L, 4.6 mol / L, and 4.8 mol / L. The concentration of Me ions in solutions containing lithium and Me salts is any value between 1.0 mol / L and 5.0 mol / L, or any range between two values; the concentration of Me ions in solutions containing lithium and Me salts is any value between 1.0 mol / L, 1.2 mol / L, 1.4 mol / L, 1.5 mol / L, 1.6 mol / L, 1.8 mol / L, 2.0 mol / L, 2.2 mol / L, 2.4 mol / L, 2.5 mol / L, 2.6 mol / L, 2.8 mol / L, and 3.0 mol / L, or any range between two values.

[0137] In some embodiments, mixing a solution containing Li and Me elements with a carbonate solution specifically involves mixing a lithium salt solution, a Me salt solution, and a carbonate solution, or mixing a solution containing lithium and Me salts with a carbonate solution.

[0138] Thirdly, embodiments of this application provide a lithium oxide precursor, the chemical formula of which is Li a MtC b Mt contains nickel and manganese, C contains O, 0.6≤a≤2.2, 1.2≤b≤2.2, and optionally, Mt further includes one or more of Co, Al, Na, K, Ca, Sr, Y, Ti, Zr, Nb, Sb, Fe, Cu, and Zn, and optionally, 0.9≤a≤1.5.

[0139] In this embodiment of the application, Mt is [Mt1] c1 Mt2 c2 Mt3 c3 ...Mtn cn ], where Mt1, Mt2, Mt3......Mtn are all different and are independently selected from one of Co, Al, Na, K, Ca, Sr, Y, Ti, Zr, Nb, Sb, Fe, Cu, Zn, and c1, c2, c3......cn are the same or different, and c1+c2+c3+......+cn=1.

[0140] In the embodiments of this application, the average valence state of Mt is +2.

[0141] For example, the value of 'a' can be any value from 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, and 2.2, or a range between any two. Optionally, 0.9 ≤ a ≤ 1.5.

[0142] For example, the value of b can be any value among 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1 and 2.2 or a range between any two.

[0143] In this embodiment, the chemical formula Li a MtC b The values ​​of a and b in the formula can maintain the valence equilibrium of the chemical formula.

[0144] In some embodiments, the lithium oxide precursor is prepared by pre-sintering from the lithium carbonate precursor in the first aspect of this application or the lithium carbonate precursor prepared by the preparation method in the second aspect of this application.

[0145] In some embodiments, the pre-sintering temperature is 500°C-800°C.

[0146] For example, the pre-sintering temperature is any value or a range between any two of 500°C, 520°C, 540°C, 550°C, 560°C, 580°C, 600°C, 620°C, 640°C, 650°C, 660°C, 680°C, 700°C, 720°C, 740°C, 750°C, 760°C, 780°C, and 800°C.

[0147] In some embodiments, the pre-sintering heating rate is 1–3 °C / min, and the pre-sintering time is 8–15 h.

[0148] For example, the heating rate of the pre-sintering is any value or a range between any two of 1℃ / min, 1.2℃ / min, 1.4℃ / min, 1.5℃ / min, 1.6℃ / min, 1.8℃ / min, 2℃ / min, 2.2℃ / min, 2.4℃ / min, 2.5℃ / min, 2.6℃ / min, 2.8℃ / min, and 3℃ / min.

[0149] For example, the pre-sintering time is any value or a range between any two of 8h, 8.5h, 9h, 9.5h, 10h, 10.5h, 11h, 11.5h, 12h, 12.5h, 13h, 13.5h, 14h, 14.5h and 15h.

[0150] Fourthly, embodiments of this application provide a cathode material, which is prepared by sintering the lithium carbonate precursor in the first aspect of this application, or the lithium carbonate precursor prepared by the preparation method in the second aspect of this application, or the lithium oxide precursor in the third aspect of this application.

[0151] In some embodiments, the sintering temperature is 810℃~900℃ and the sintering time is 8h~15h.

[0152] For example, the sintering temperature is any value or a range between any two of 810°C, 820°C, 830°C, 840°C, 850°C, 860°C, 870°C, 880°C, 890°C, and 900°C.

[0153] For example, the sintering time is any value or a range between any two of 8h, 8.5h, 9h, 9.5h, 10h, 10.5h, 11h, 11.5h, 12h, 12.5h, 13h, 13.5h, 14h, 14.5h and 15h.

[0154] Fifthly, embodiments of this application provide a lithium-ion battery comprising the positive electrode material described in the fourth aspect of this application.

[0155] The lithium-ion battery provided in this application embodiment includes the above-mentioned positive electrode material, which enables the battery to have high capacity, good cycle and rate performance.

[0156] In some embodiments, the positive electrode material, conductive carbon black, and binder can be mixed into a slurry and coated onto the current collector to form a positive electrode sheet. Exemplarily, the current collector is aluminum foil.

[0157] Understandably, lithium-ion batteries also include negative electrode plates, separators, and electrolytes.

[0158] The specific composition and structure of the negative electrode sheet can be selected according to the type of lithium-ion battery, and the embodiments of this application are not limited in this regard.

[0159] In some embodiments, the separator may be a diaphragm. This application does not impose any particular limitation on the type of diaphragm; any known porous diaphragm with good chemical and mechanical stability may be selected.

[0160] For example, the main material of the separator is selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation.

[0161] Electrolytes can be liquid, gel, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0162] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0163] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0164] Sixthly, this application provides an electrical device, including the lithium-ion battery described in the fifth aspect of this application.

[0165] Example

[0166] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on weight, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0167] Example 1:

[0168] This embodiment provides a lithium carbonate precursor with the chemical formula Li. 1.076 Ni 0.6 Co 0.1 Mn 0.3 (CO3) 1.538 The secondary particles are spherical, and Ni, Co, Mn, and Li are uniformly distributed in the material. The primary particles on the surface of the precursor material are irregularly plate-like, with an average width of 0.50-1.35 μm and an average thickness of 20 nm-50 nm for the plate-like primary particles on different secondary particles.

[0169] The method for preparing the lithium carbonate precursor in this embodiment includes the following steps:

[0170] Solution preparation: Dissolve nickel sulfate, cobalt sulfate, manganese sulfate, and lithium sulfate crystals to prepare a solution containing nickel sulfate, cobalt sulfate, manganese sulfate, and lithium sulfate. The lithium ion content in the solution is 2.5 mol / L, and the total nickel, cobalt, and manganese ion content is 2.0 mol / L. The molar ratio of the elements is Ni:Co:Mn = 60:10:30. Dissolve sodium carbonate crystals to prepare a 3.0 mol / L sodium carbonate solution.

[0171] Under an inert gas atmosphere: pure water is added to the reactor, nitrogen is introduced as a protective gas, the temperature is controlled at 50℃, and the reaction speed is 800 r / min;

[0172] Reaction process: Under stirring, the feed is pumped into the reactor at a set flow rate. The flow rate of the mixed metal salt solution is 3.0% / h of the available reactor volume, and the flow rate of the sodium carbonate solution is 3.5% / h of the available reactor volume for co-precipitation reaction. When the reaction slurry reaches the upper limit of the reactor volume, the mother liquor is discharged through a concentration device. The discharge rate of the mother liquor is consistent with the total feed rate. The pH value of the reaction is controlled between 9.2 and 9.3. The reaction is stopped when the particle size Dv50 of the material meets the requirements.

[0173] Post-processing steps: After the synthesis stage is completed, the materials are washed, dried, sieved, and demagnetized to obtain the target precursor.

[0174] This embodiment also provides a cathode material, the preparation method of which includes the following steps:

[0175] Two kg of the lithium carbonate precursor prepared above was sintered in an air atmosphere using a box furnace at a sintering temperature of 850°C for 10 hours. After cooling to room temperature, it was crushed and sieved to obtain the cathode material.

[0176] Example 2

[0177] This embodiment provides a lithium carbonate precursor with the chemical formula Li. 1.102 Ni 0.59 Co 0.095 Mn 0.315 (CO3) 1.551 The secondary particles are spherical, and Ni, Co, Mn, and Li are uniformly distributed in the material. The primary particles on the surface of the precursor material are irregularly plate-like, with an average width of 0.1-0.2 μm for the plate-like primary particles on different secondary particles.

[0178] Example 2 was prepared using a method similar to that of Example 1, except that:

[0179] (1) In the solution preparation step, a solution containing nickel sulfate, cobalt sulfate, manganese sulfate and lithium sulfate is prepared. The lithium ion content in the solution is 3.0 mol / L, the total content of nickel, cobalt and manganese ions is 2.0 mol / L, and the element ratio Ni:Co:Mn=59:9.5:31.5;

[0180] (2) In the reaction process, the flow rate of the mixed metal salt solution is 2.0% / h of the available volume of the reactor, and the flow rate of the sodium carbonate solution is 2.5% / h of the available volume of the reactor; the pH value of the reaction is controlled between 8.6 and 8.7.

[0181] This embodiment also provides a positive electrode material, which is prepared using a method similar to that in Example 1, except that the high-temperature sintering time is 12 hours.

[0182] Example 3

[0183] This embodiment provides a lithium carbonate precursor with the chemical formula Li. 1.076 Ni 0.6 Co 0.1 Mn 0.3 (CO3) 1.538 The secondary particles are spherical, and Ni, Co, Mn, and Li are uniformly distributed in the material. The primary particles on the surface of the precursor material are irregularly plate-like, with an average width of 0.5-1.2 μm and an average thickness of 20 nm-50 nm for the plate-like primary particles on different secondary particles.

[0184] Example 3 was prepared using a method similar to that of Example 1, except that:

[0185] (1) In the reaction process, the flow rate of the mixed metal salt solution is 4.0% / h of the available volume of the reactor, and the flow rate of the sodium carbonate solution is 4.7% / h of the available volume of the reactor.

[0186] This embodiment also provides a positive electrode material, which is prepared using a method similar to that in Example 1, except that the sintering temperature is 860°C.

[0187] Example 4

[0188] This embodiment provides a lithium carbonate precursor with the chemical formula Li. 1.077 Ni 0.605 Co 0.095 Mn 0.3 (CO3) 1.539 The secondary particles are spherical, and Ni, Co, Mn, and Li are uniformly distributed in the material. The primary particles on the surface of the precursor material are irregularly plate-like.

[0189] Example 4 was prepared using a method similar to that of Example 1, except that:

[0190] (1) In the solution preparation step, a solution containing nickel sulfate, cobalt sulfate, manganese sulfate and lithium sulfate is prepared. The lithium ion content in the solution is 2.8 mol / L, the total content of nickel, cobalt and manganese ions is 2.0 mol / L, and the element ratio Ni:Co:Mn = 60.5:9.5:30; sodium carbonate crystals are dissolved to prepare a 4.0 mol / L sodium carbonate solution.

[0191] (2) In the reaction process, the flow rate of the mixed metal salt solution is 5.0% / h of the available volume of the reactor, and the flow rate of the sodium carbonate solution is 4.5% / h of the available volume of the reactor.

[0192] This embodiment also provides a positive electrode material, which is prepared using a method similar to that in Example 1, except that the sintering temperature is 880°C.

[0193] Example 5

[0194] This embodiment provides a lithium carbonate precursor with the chemical formula Li. 1.059 Ni 0.6 Co 0.1 Mn 0.3 (CO3) 1.530 The secondary particles are spherical, and Ni, Co, Mn, and Li are uniformly distributed in the material. The primary particles on the surface of the precursor material are irregularly plate-like.

[0195] Example 5 was prepared using a method similar to that of Example 1, except that:

[0196] (1) In the solution preparation step, a solution containing nickel sulfate, cobalt sulfate, manganese sulfate and lithium sulfate is prepared. The lithium ion content in the solution is 2.8 mol / L, the total content of nickel, cobalt and manganese ions is 2.0 mol / L, and the element ratio Ni:Co:Mn=60:10:30; sodium carbonate crystals are dissolved to prepare a 3.0 mol / L sodium carbonate solution.

[0197] (2) In the reaction process, the flow rate of the mixed metal salt solution is 4.0% / h of the available volume of the reactor, and the flow rate of the sodium carbonate solution is 4.5% / h of the available volume of the reactor; the pH value of the reaction is controlled between 8.8 and 8.9.

[0198] This embodiment also provides a positive electrode material, which is prepared using the same method as in Example 1.

[0199] Example 6

[0200] This embodiment provides a lithium carbonate precursor with the chemical formula Li. 1.347Ni 0.60 Co 0.1 Mn 0.3 (CO3) 1.674 The secondary particles are spherical, and Ni, Co, Mn, and Li are uniformly distributed in the material. The primary particles on the surface of the precursor material are irregularly plate-like.

[0201] Example 6 was prepared using a method similar to that of Example 1, except that:

[0202] (1) In the solution preparation step, a solution containing nickel sulfate, cobalt sulfate, manganese sulfate and lithium sulfate is prepared. The lithium ion content in the solution is 5.0 mol / L, the total content of nickel, cobalt and manganese ions is 2.0 mol / L, and the element ratio Ni:Co:Mn=60:10:30; sodium carbonate crystals are dissolved to prepare a 5.0 mol / L sodium carbonate solution.

[0203] (2) Control the pH value of the reaction between 9.5 and 9.6.

[0204] This embodiment also provides a positive electrode material, which is prepared using the same method as in Example 1.

[0205] Example 7

[0206] This embodiment provides a lithium carbonate precursor with the chemical formula Li. 0.918 Ni 0.60 Co 0.1 Mn 0.30 (CO3) 1.459 The secondary particles are spherical, and Ni, Co, Mn, and Li are uniformly distributed in the material. The primary particles on the surface of the precursor material are irregularly plate-like.

[0207] (1) In the solution preparation step, a solution containing nickel sulfate, cobalt sulfate, manganese sulfate and lithium sulfate is prepared. The lithium ion content in the solution is 2.5 mol / L, the total content of nickel, cobalt and manganese ions is 2.0 mol / L, and the element ratio Ni:Co:Mn=60:10:30; sodium carbonate crystals are dissolved to prepare a 4.0 mol / L sodium carbonate solution.

[0208] (2) In the reaction process, the flow rate of the mixed metal salt solution is 3.0% / h of the available volume of the reactor, and the flow rate of the sodium carbonate solution is 1.8% / h of the available volume of the reactor; the pH value of the reaction is controlled between 9.0 and 9.3.

[0209] This embodiment also provides a positive electrode material, which is prepared using the same method as in Example 1.

[0210] Example 8

[0211] This embodiment provides a lithium oxide precursor, the preparation method of which includes the following steps:

[0212] Two kg of the lithium carbonate precursor prepared in Example 1 was sintered in an air atmosphere using a box furnace at a sintering temperature of 600°C for 10 hours. After cooling to room temperature, it was pulverized and sieved to obtain the lithium oxide precursor.

[0213] This embodiment also provides a cathode material, the preparation method of which includes the following steps:

[0214] Two kilograms of the lithium oxide precursor prepared above were sintered in an air atmosphere using a box furnace at a sintering temperature of 850°C for 10 hours. After cooling to room temperature, the precursor was pulverized and sieved to obtain the cathode material.

[0215] Comparative Example 1

[0216] This comparative example provides a carbonate-containing cathode material precursor with the chemical formula Ni. 0.60 Co 0.10 Mn 0.3 CO3, the secondary particles are spherical, and Ni, Co and Mn are uniformly distributed in the material.

[0217] Comparative Example 1 was prepared using a method similar to that of Example 1, except that:

[0218] (1) In the solution preparation step, a solution containing nickel sulfate, cobalt sulfate and manganese sulfate is prepared and combined to form a metal solution with a total metal content of 2 mol / L and an element ratio of Ni:Co:Mn = 60:10:30; sodium carbonate crystals are dissolved to prepare a 4.3 mol / L sodium carbonate solution;

[0219] (2) Control the pH value of the reaction between 8.0 and 8.5.

[0220] This comparative example also provides a cathode material, prepared using the following method:

[0221] Lithium carbonate and a comparative precursor were mixed uniformly in a high-speed mixer at a total metal content: lithium ratio of 1:1.05, and sintered at 850°C for 12 hours to obtain the cathode material.

[0222] Comparative Example 2

[0223] This embodiment provides a cathode material precursor with the chemical formula Li. 0.572 Ni 0.60 Co 0.1 Mn 0.30 (CO3) 1.286 The secondary particles are spherical, and Ni, Co, Mn, and Li are uniformly distributed in the material.

[0224] Comparative Example 2 was prepared using a method similar to that of Example 1, except that:

[0225] (1) In the solution preparation step, a solution containing nickel sulfate, cobalt sulfate, manganese sulfate and lithium sulfate is prepared. The lithium ion content in the solution is 2.1 mol / L, the total content of nickel, cobalt and manganese ions is 2.0 mol / L, and the element ratio Ni:Co:Mn=60:10:30; sodium carbonate crystals are dissolved to prepare a 4.0 mol / L sodium carbonate solution.

[0226] (2) In the reaction process, the flow rate of the mixed metal salt solution is 3.0% / h of the available volume of the reactor, and the flow rate of the sodium carbonate solution is 1.8% / h of the available volume of the reactor; the pH value of the reaction is controlled between 7.5 and 8.5.

[0227] This comparative example also provides a cathode material, which is prepared using the same method as in Example 1.

[0228] Comparative Example 3

[0229] This embodiment provides a cathode material precursor with the chemical formula Li. 0.271 Ni 0.60 Co 0.10 Mn 0.30 (CO3) 1.136 The secondary particles are spherical, and Ni, Co, Mn, and Li are uniformly distributed in the material.

[0230] Comparative Example 3 was prepared using a method similar to that of Example 1, except that:

[0231] (1) In the solution preparation step, a solution containing nickel sulfate, cobalt sulfate, and manganese sulfate is prepared, with a total content of nickel, cobalt, and manganese ions of 2.5 mol / L and an element ratio of Ni:Co:Mn = 60:10:30; a lithium sulfate solution is prepared separately, with a lithium ion content of 1.0 mol / L; and sodium carbonate crystals are dissolved to prepare a 4.5 mol / L sodium carbonate solution.

[0232] (2) In the reaction process, the flow rate of the metal salt solution is 2.0% / h of the available volume of the reactor, the flow rate of the lithium sulfate solution is 3.0% / h of the available volume of the reactor, and the flow rate of the sodium carbonate solution is 4.0% / h of the available volume of the reactor; the pH value of the reaction is controlled between 9.9 and 10.0.

[0233] This comparative example also provides a cathode material, which is prepared using the same method as in Example 1.

[0234] Comparative Example 4

[0235] This comparative example provides a cathode material, which is prepared using the following method:

[0236] Lithium carbonate and the precursor of Comparative Example 1 were mixed uniformly in a high-speed mixer at a total metal content: lithium ratio of 1:1.35, and sintered at 850°C for 12 h to obtain the cathode material.

[0237] Comparative Example 5

[0238] This comparative example provides a cathode material, which is prepared using the following method:

[0239] Lithium carbonate and the precursor of Comparative Example 3 were mixed uniformly in a high-speed mixer at a ratio of transition metal content: lithium = 1:0.78, and sintered at 850°C for 12 h to obtain the cathode material.

[0240] Test case

[0241] The lithium oxide precursors prepared in the examples and the cathode material precursors prepared in the comparative examples, as well as the batteries, were subjected to physicochemical data and electrochemical performance tests.

[0242] The particle size D of secondary particles V 50: Measured using a laser particle size analyzer (instrument model: Mastersizer3000), referring to the national standard GB / T 19077-2016 Particle size analysis by laser diffraction.

[0243] Tap density test method: The tap density was determined by a powder tap density tester (model: Dandong Baite BT-302) in accordance with the national standard GB / T 5162-2021 Determination of tap density of metal powders.

[0244] Specific surface area testing method: Surface area was measured using a fully automated nitrogen adsorption surface area analyzer (instrument model: BELPREP-VACII / BELSORP-MINI-X), referring to the national standard GB / T 19587-2017 "Determination of Specific Surface Area of ​​Solid Substances by Gas Adsorption BET Method". The physicochemical data of the cathode material precursors in Examples 1-7 and Comparative Examples 1-3 are shown in Tables 1 and 2.

[0245] XRD testing method: X-ray diffraction parameters are as follows: Radiation source: CuK rays (1.54059 Å); Scanning mode: Scanning speed is 8° / min, step angle is 0.02°, Solar slit is 5°; Measurement range: 2θ = 5°~80°.

[0246] Table 1 Summary of some parameters of the precursors of the examples and comparative examples.

[0247]

[0248] Table 2 Summary of crystal structure data of cathode materials in the examples and comparative examples

[0249]

[0250]

[0251] Electrochemical performance testing: The positive electrode materials obtained in the above examples and comparative examples were mixed with conductive carbon black and binder PVDF (polyvinylidene fluoride) in a vacuum glove box at a mass ratio of 8:1:1 to form a slurry, which was then coated on aluminum foil to form a positive electrode sheet. The negative electrode sheet was made of lithium metal sheet, and the electrolyte was 1 mol / L LiPF6 / EC:DMC (volume ratio 1:1). The battery case, positive and negative electrode sheets, separator, spring sheet, and gasket were assembled into a button battery in a vacuum glove box.

[0252] Electrochemical performance was tested using the Blue Electricity testing system at 25°C and 2.8–4.3 V, with 1C = 210 mA / g. The test results for the button batteries prepared in Examples 1–8 and Comparative Examples 1–5 are shown in Table 3.

[0253] Table 3 shows the performance indicators of the cathode materials prepared from the precursors of the examples and comparative examples.

[0254]

[0255] Combination Figures 1 to 11 As shown in Tables 1 to 3, the lithium carbonate precursor of this application includes spherical secondary particles. The surface of the secondary particles is covered with irregularly shaped sheet-like primary particles arranged in a disordered manner. The cathode material prepared from it has excellent capacity, rate capability, and cycle performance. Among them, the precursor of Comparative Example 3 has a low lithium content at the end and no lithium was mixed during the sintering of the rear end, so its electrical performance data could not be obtained.

[0256] By simultaneously introducing lithium during the precursor co-precipitation process, a uniform distribution of lithium in the precursor is achieved. This not only avoids the problem of impurity phases caused by local lithium excess or deficiency during later sintering, but also helps to form a complete layered structure, reduce cation mixing, and improve the stability of the crystal structure.

[0257] Uniform lithium distribution significantly improves the diffusion rate of lithium ions and reduces migration obstacles, thereby enabling the material to exhibit excellent rate performance and cycle performance.

[0258] At high temperatures, the lamellar structure is more likely to form complete single crystal particles with high crystallinity and low cation mixing, while the spherical secondary particles help to form a single crystal structure with uniform internal stress and few defects, which together promote the utilization of the cathode material's capacity and the improvement of cycle stability.

[0259] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A lithium carbonate precursor, characterized in that, The lithium carbonate precursor comprises spherical secondary particles, the surface of which includes multiple plate-like primary particles.

2. The lithium carbonate precursor according to claim 1, characterized in that, The plate-like primary particles on the surface of the secondary particles are arranged in a disordered manner.

3. The lithium-containing carbonate precursor according to claim 1, characterized in that, The chemical formula of the lithium carbonate precursor is Li x MeB z Where 0.6≤x≤2.2, 1.2≤z≤2.2; The Me includes Mn and Ni, and optionally, the Me also includes one or more of Co, Al, Na, K, Ca, Sr, Y, Ti, Zr, Nb, Sb, Fe, Cu, and Zn; The B includes CO3, and optionally, the B also includes one or more of OH, Cl, NO3, SO4, HCO3, H2PO4, HPO4, and PO4.

4. The lithium-containing carbonate precursor according to any one of claims 1-3, characterized in that, The lithium carbonate precursor satisfies at least one of the following conditions: A. The width of the primary particles is 0.1μm to 1.5μm, and the thickness is ≤50nm; B. The volumetric particle size D of the precursor V 50 is 2.0μm~15.0μm, optional, D V 50 ranges from 4.0 μm to 12.0 μm; C. The particle size distribution range of the precursor is 0.3 to 1.6, and optionally, the particle size distribution range is 1.1 to 1.4; D. The specific surface area of ​​the precursor is 30 m². 2 / g~100m 2 / g; E. The tap density of the precursor is 1.0 g / m³. 3 ~2.0g / m 3 ; F. The sphericity of the precursor is 80% to 100%, and optionally, it is 85% to 90%. G. The Li x MeB z In the equation, 0.9 ≤ x ≤ 1.

5.

5. A method for preparing a lithium carbonate precursor, characterized in that, include: The lithium-containing carbonate precursor is obtained by co-precipitation reaction of a solution containing Li and Me elements with a carbonate solution under an inert gas atmosphere.

6. The method for preparing the lithium carbonate precursor according to claim 5, characterized in that, The preparation method satisfies at least one of the following conditions: (1) The preparation method further includes a solution preparation step, wherein the solution preparation includes preparing a lithium salt solution, a Me salt solution and a carbonate solution respectively; and / or the solution preparation includes preparing a solution containing lithium salt and Me salt and a carbonate solution respectively; (2) The pH value at which the coprecipitation reaction takes place is 8.6–9.6; (3) The temperature of the coprecipitation reaction is 45-65℃; (4) The molar ratio of Li ions, Me ions and carbonate ions in the coprecipitation reaction is 1:(1.05~2.5):(1.5~3.0); (5) The preparation method further includes post-treatment of the precipitate; optionally, the post-treatment includes solid-liquid separation, washing, drying and demagnetization.

7. The method for preparing the lithium-containing carbonate precursor according to claim 5 or 6, characterized in that, The preparation method satisfies at least one of the following conditions: a. The lithium salt is selected from one or more of lithium sulfate, lithium nitrate, or lithium chloride; b. The Me salt comprises a nickel salt and a manganese salt. Optionally, the Me salt further comprises one or more of the following: Co salt, Al salt, Na salt, K salt, Ca salt, Sr salt, Y salt, Ti salt, Zr salt, Nb salt, Sb salt, Fe salt, Cu salt, and Zn salt. Optionally, the nickel salt is selected from one or more of the following: sulfate, nickel nitrate, or nickel chloride. Optionally, the manganese salt is selected from one or more of the following: manganese sulfate, manganese nitrate, or manganese chloride. c. The carbonate is selected from one or more of lithium carbonate, sodium carbonate, or potassium carbonate; d. The concentration of the carbonate solution is 2.0 mol / L to 5.0 mol / L; e. The lithium ion concentration in the lithium salt solution is 2 mol / L to 5 mol / L; f. The concentration of Me ions in the Me salt solution is 1 mol / L to 3 mol / L; g. The concentration of lithium ions in the solution containing lithium salt and Me salt is 2 mol / L to 5 mol / L, and the concentration of Me ions is 1 mol / L to 3 mol / L; h. The specific operation of mixing the solution containing Li and Me elements with the carbonate solution is to mix the lithium salt solution, the Me salt solution and the carbonate solution, or to mix the solution containing lithium salt and Me salt with the carbonate solution.

8. A lithium oxide precursor, characterized in that, The chemical formula of the lithium oxide precursor is Li a MtC b Mt contains nickel and manganese, C contains O, 0.6≤a≤2.2, 1.2≤b≤2.2; Optionally, the Mt further includes one or more of Co, Al, Na, K, Ca, Sr, Y, Ti, Zr, Nb, Sb, Fe, Cu, and Zn; Optional, where 0.9 ≤ a ≤ 1.

5.

9. A lithium oxide precursor, characterized in that, The lithium oxide precursor is prepared by pre-sintering of raw materials containing the lithium carbonate precursor according to any one of claims 1-4 or the lithium carbonate precursor prepared by the preparation method according to claims 6-7; Optionally, the pre-sintering temperature is 500-800℃, and further optionally, the pre-sintering heating rate is 1-3℃ / min, and the pre-sintering time is 8-15h.

10. A positive electrode material, characterized in that, The lithium carbonate precursor prepared by any one of the lithium carbonate precursors according to claims 1-4, the lithium carbonate precursor prepared by the preparation method according to claims 5-7, or the lithium oxide precursor according to claims 8-9 is obtained by sintering.

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