A lithium ion battery positive electrode material and a precursor thereof, a preparation method, a positive electrode sheet, and a battery

Abstract

The embodiment of the present application relates to the technical field of lithium ion battery material, and provides a precursor of a lithium ion battery positive electrode material and a preparation method thereof, a lithium ion battery positive electrode material and a preparation method thereof, a positive electrode sheet and a battery. The expression of the precursor is Fe X Mn 1‑X‑Y {M} Y PO4, wherein 0.1 <= X <= 0.4, 0.005 <= Y <= 0.02, M includes Nb, and M can further optionally include at least one of Mo, Ti and V. The preparation method of the precursor of the lithium ion battery positive electrode material comprises the following steps: stirring and mixing an iron source, a manganese source, deionized water and phosphoric acid, and filtering to remove insoluble substances to obtain a first solution; adding a doped metal source after nanoization to the first solution to obtain a second solution; adding an organic solvent to the second solution to obtain a precipitate; and washing, drying and sintering the precipitate to obtain the precursor; the doped metal source is an oxide of M; the ratio of the amount of substance of the iron source, the manganese source and the doped metal source is a ratio as shown in the expression of the precursor, in terms of metal elements.

Description

Technical Field

[0001] This application relates to the field of lithium-ion battery materials technology, specifically to a precursor of a lithium-ion battery cathode material and its preparation method, a lithium-ion battery cathode material and its preparation method, a cathode sheet and a battery. Background Technology

[0002] Existing lithium-ion battery cathode materials and their precursors suffer from low compaction density. Summary of the Invention

[0003] The first aspect of this application provides a method for preparing a precursor of a lithium-ion battery cathode material, wherein the precursor has the following expression: Fe X Mn 1-X-Y {M} Y PO4, where 0.1≤X≤0.4, 0.005≤Y≤0.02, and M includes Nb, and M may also selectively include at least one of Mo, Ti, and V; the preparation method of the precursor of the lithium-ion battery cathode material includes:

[0004] Iron source, manganese source, deionized water and phosphoric acid are stirred and mixed, and the insoluble matter is removed by filtration to obtain the first solution;

[0005] The doped metal source is nano-sized and added to the first solution to obtain the second solution;

[0006] An organic solvent is added to the second solution to obtain a precipitate; and

[0007] The precipitate was washed, dried, and sintered to obtain the precursor;

[0008] Wherein, the doped metal source is an oxide of M; and the ratio of the amounts of the iron source, the manganese source and the doped metal source, in terms of metal elements, is the ratio of the number of Fe, Mn and M atoms as shown in the expression for the precursor.

[0009] In the above-mentioned method for preparing precursors of lithium-ion battery cathode materials, since the binding energy of doped metals with oxygen (such as Nb (4.44eV), Mo (4.05eV), Ti (3.69eV), V (3.53eV)) is higher than that of other common transition metals (W, Cr, Mn, Fe, Ni, Co, Zr, etc.), they can provide nuclei for particle crystallization at a lower sintering temperature, thereby improving the density of the precursor, i.e., the compaction density.

[0010] A second aspect of this application provides a precursor for a lithium-ion battery cathode material, wherein the precursor is expressed as Fe... X Mn 1-X-Y {M} YPO4, where 0.1≤X≤0.4, 0.005≤Y≤0.02, and M includes Nb, and M may also optionally include at least one of Mo, Ti and V.

[0011] In the precursor of the above-mentioned lithium-ion battery cathode material, since the binding energy between the doped metal and oxygen is higher than that of other common transition metals, it can provide grain crystal nuclei at a lower sintering temperature, thereby improving the density of the precursor, i.e., the compaction density.

[0012] A third aspect of this application provides a method for preparing a lithium-ion battery cathode material, wherein the lithium-ion battery cathode material is expressed as Li… Z Fe X Mn 1-X-Y {M} Y PO4 / C, where 0.1≤X≤0.4, 0.005≤Y≤0.02, 1.005≤Z≤1.05, and M includes Nb, and M may also selectively include at least one of Mo, Ti, and V; the preparation method of the lithium-ion battery cathode material includes:

[0013] Prepare a precursor according to the method for preparing a precursor of a lithium-ion battery cathode material as described in the first aspect of this application, or provide a precursor of a lithium-ion battery cathode material as described in the second aspect of this application.

[0014] The precursor, lithium source, and carbon source are nano-sized, dried, sintered, and crushed to obtain the lithium-ion battery cathode material.

[0015] Wherein, in terms of metal elements, the ratio of the amount of the lithium source to the amount of the precursor is the ratio of the number of Li atoms to the number of precursor atoms as shown in the expression for the lithium-ion battery cathode material.

[0016] The above-mentioned method for preparing lithium-ion battery cathode materials, in addition to the advantages of the method for preparing the precursor of lithium-ion battery cathode materials described in the first aspect, also has the following advantages: Firstly, the doping elements have good catalytic performance, which can improve the graphitization degree of the carbon source during the carbonization process, reduce the amount of carbon source used, and reduce the presence of free carbon, thereby also improving the compaction density of the lithium-ion battery cathode material; secondly, the doping elements in lithium manganese iron phosphate Li Z Fe X Mn 1-X-Y {M} Y In PO4 / C, excess lithium forms lithides (LiNbO3, Li2MoO4, Li4Ti5O3). 12Lithium-ion conductors (such as Li3VO4) can further improve the lithium-ion conductivity of lithium-ion battery cathode materials, thereby enhancing their electrochemical performance. Furthermore, the aforementioned methods for preparing lithium-ion battery cathode materials effectively reduce environmental impact during the preparation process, providing a pollution-free and sustainable green process route for subsequent large-scale production.

[0017] A fourth aspect of this application provides a lithium-ion battery cathode material, wherein the lithium-ion battery cathode material is expressed as Li… Z Fe X Mn 1-X-Y {M} Y PO4 / C, where 0.1≤X≤0.4, 0.005≤Y≤0.02, 1.005≤Z≤1.05, and M includes Nb, and M may also optionally include at least one of Mo, Ti and V.

[0018] In lithium-ion battery cathode materials, doped metals, due to their higher binding energy with oxygen compared to other common transition metals, can provide nuclei for particle crystallization at lower sintering temperatures, thereby increasing the compaction density of the precursor, i.e., the compaction density. On one hand, doped elements possess excellent catalytic properties, enhancing the graphitization degree of carbon sources during carbonization, reducing the amount of carbon source used, and decreasing the presence of free carbon, which also improves the compaction density of lithium-ion battery cathode materials. On the other hand, doped elements in lithium-ion battery cathode materials... Z Fe X Mn 1-X-Y {M} Y In PO4 / C, excess lithium forms lithides (LiNbO3, Li2MoO4, Li4Ti5O3). 12 Lithium-ion conductors (such as Li3VO4) can further improve the lithium-ion conductivity of lithium-ion battery cathode materials, thereby enhancing their electrochemical performance.

[0019] The fifth aspect of this application provides a positive electrode sheet, the positive electrode sheet comprising a current collector and a positive electrode active material layer located on the current collector, the positive electrode active material layer comprising a lithium-ion battery positive electrode material obtained by the preparation method of the lithium-ion battery positive electrode material according to the third aspect of this application; or, the positive electrode active material comprising a lithium-ion battery positive electrode material according to the fourth aspect of this application.

[0020] The aforementioned positive electrode sheet possesses at least the advantages of the preparation method of the lithium-ion battery positive electrode material described in the third aspect or the lithium-ion battery positive electrode material described in the fourth aspect, which will not be elaborated further here.

[0021] The sixth aspect of this application provides a battery, the battery including a positive electrode, a negative electrode and a separator located between the positive electrode and the negative electrode, wherein the positive electrode is the positive electrode described in the fifth aspect of this application.

[0022] The battery described above has at least the advantages of the positive electrode sheet described in the fifth aspect of this application, which will not be repeated here. Attached Figure Description

[0023] Figure 1 This is a scanning electron microscope (SEM) image of the lithium iron manganese phosphate precursor in Example 1 of this application.

[0024] Figure 2 This is a SEM image of the lithium-ion battery cathode material in Example 1 of this application.

[0025] Figure 3 This is an X-ray diffraction (XRD) pattern of the lithium-ion battery cathode material in Example 1 of this application.

[0026] Figure 4 This is a graph showing the compaction density and conductivity of the lithium-ion battery cathode material in Example 1 of this application.

[0027] Figure 5 This is a cross-sectional SEM image of the lithium-ion battery cathode material in Example 1 of this application.

[0028] Figure 6 The charge-discharge curves are shown for the lithium-ion battery cathode material in Example 1 of this application.

[0029] Figure 7 Figures (a) and (b) in the figure are SEM images and cross-sectional SEM images of the lithium-ion battery cathode material obtained in Comparative Example 1, respectively. Detailed Implementation

[0030] Lithium iron manganese phosphate (LiFeMnPO4) has an olivine-type structure and boasts advantages such as abundant raw material resources, low cost, and environmental friendliness, attracting increasing attention. This material, on the one hand, contains polyanionic PO4 within its unit cell. 3- The structure exhibits good thermal stability and overcharge resistance; on the other hand, Mn(Vs) Li+ / Li The presence of ) allows lithium iron manganese phosphate to have a discharge voltage plateau at 4.0V, compared to 3.4V (Vs) for lithium iron phosphate. Li+ / Li The improvement is significant, and the energy density is increased. Therefore, lithium iron manganese phosphate has a promising future among the cathode materials for power lithium-ion batteries where safety is currently a primary concern.

[0031] In lithium manganese iron phosphate (LFP), manganese has a +2 valence, and its outer valence bond electron configuration is [Ar]3d5, with each of the five electrons occupying a 3d orbital, exhibiting a high-spin state and no empty 3d orbitals. During the sintering process of organic carbon sources under an inert atmosphere to form a carbon layer, LFP exhibits poorer catalytic performance compared to LFP due to the aforementioned reasons. Therefore, the graphitization degree and uniformity of the carbon layer in LFP materials are poor, resulting in lower electronic conductivity and affecting its conventional electrochemical performance. In practical applications, methods such as reducing the primary particle size, adding conductive agents like graphene, and increasing the carbon content are commonly used to improve performance. While these technologies have improved the performance of LFP materials, they also result in low compaction density, increased specific surface area, and higher costs, which to some extent hinders the large-scale application of LFP materials.

[0032] Authorized patent CN113942990B discloses a lithium manganese iron phosphate precursor (NH4)Mn 1-x-y Fe x M y PO4·H2O was used as a precursor to prepare lithium manganese iron phosphate materials, which exhibit a dense spherical aggregate structure and good compaction density. Patent application No. 202211611236.X discloses a modified lithium manganese iron phosphate cathode material and its preparation method. This method involves adding lithium, manganese, iron, and doped metal sources to a phosphorus, ammonia, and hydrogen peroxide solution for grinding to obtain lithium manganese iron phosphate powder. This powder is then mixed with a fast-ion conductor solution and ground again, followed by sintering to obtain the modified lithium manganese iron phosphate cathode material. These preparation methods all yield high-performance lithium iron manganese phosphate products. However, all these processes involve ammonia nitrogen reactions, which will pose a pollution risk to the environment during subsequent industrial-scale production.

[0033] Patent application number 202210241338.0 discloses a method for preparing nanoscale carbon composite lithium manganese iron phosphate cathode material for lithium-ion batteries. The method involves grinding and mixing prepared manganese oxalate and ferrous oxalate precursors with lithium, carbon, and phosphorus sources, followed by spray drying and granulation, and sintering in a protective gas atmosphere to obtain nanoscale lithium manganese iron phosphate cathode material. This invention uses a pure aqueous solvent, making the process simple, environmentally friendly, and suitable for large-scale production. However, the process uses oxalate to prepare the precursors, resulting in higher costs. Furthermore, the sintering process generates a significant amount of gas, which is detrimental to achieving high compaction density in the prepared lithium manganese iron phosphate material.

[0034] Application No. 202310133209.4 discloses a method for preparing lithium manganese iron phosphate cathode materials with a double-layer fibrous structure. This patent employs an electrospinning process, adjusting the precursor spinning solution to form high-manganese-content lithium manganese iron phosphate in the core and low-manganese-content lithium manganese iron phosphate in the shell. Carbon dispersion technology is used to suppress the growth of primary particles, thus obtaining a composite cathode material. While this electrospinning technology brings about material structure differentiation, it also introduces drawbacks such as higher carbon content, increased process costs, and limitations on large-scale production applications.

[0035] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0036] In this document, for the purposes of numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0037] The term "D50" refers to the particle size at which the cumulative particle size distribution of a sample reaches 50%. Physically, it means that the volume content of particles smaller than D50 accounts for 50% of the total particles, and the volume content of particles larger than D50 also accounts for 50% of the total particles. D50 is also called median diameter, median particle size, or median particle size. D50 is often used to represent the average particle size of powders.

[0038] The first aspect of this application provides a method for preparing a precursor of a lithium-ion battery cathode material, wherein the precursor has the formula Fe... X Mn 1-X-Y {M} Y PO4, where 0.1≤X≤0.4, 0.005≤Y≤0.02, and M includes Nb, and M may also optionally include at least one of Mo, Ti, and V. The preparation method of the precursor of this lithium-ion battery cathode material includes the following steps S11 to S14.

[0039] Depending on the specific requirements, certain steps in the preparation method of the precursor for the lithium-ion battery cathode material may be omitted or combined.

[0040] Step S11: Mix the iron source, manganese source, deionized water and phosphoric acid, and filter to remove insoluble matter to obtain the first solution.

[0041] Step S12: The doped metal source is nano-sized and added to the first solution to obtain the second solution.

[0042] Step S13: Add the organic solvent to the second solution to obtain a precipitate.

[0043] Step S14: The precipitate is washed, dried and sintered to obtain the precursor.

[0044] Specifically, the doped metal source is an oxide of M; the ratio of the amounts of iron source, manganese source and doped metal source, in terms of metal elements, is the ratio of the number of Fe, Mn and M atoms as shown in the precursor expression.

[0045] In the above-mentioned method for preparing the precursor of lithium-ion battery cathode material, since the binding energy of the doped metal with oxygen (such as Nb (4.44eV), Mo (4.05eV), Ti (3.69eV), V (3.53eV)) is higher than that of other common transition metals (W, Cr, Mn, Fe, Ni, Co, Zr, etc.), and the oxide of M is a Lewis acid, the oxide of M (hereinafter also referred to as the doped metal oxide) is added to the first solution (acidic solution) in the above step S12 to activate the surface without loss, thereby improving the material utilization rate.

[0046] Furthermore, in the precursor Fe X Mn 1-X-Y {M} Y During the preparation of PO4, due to the high binding energy between the dopant element and oxygen, it can provide nuclei for particle crystallization at a relatively low sintering temperature, thereby increasing the density of the precursor, i.e., the compaction density, which is beneficial to improving the volumetric energy density of the subsequent battery.

[0047] Furthermore, the aforementioned method for preparing the precursor of lithium-ion battery cathode material does not generate ammonia nitrogen pollution, has a low negative impact on the environment, and boasts high raw material economic efficiency and low product cost during the material preparation process. Moreover, the aforementioned method for preparing the precursor of lithium-ion battery cathode material is controllable, simple, and convenient, produces highly uniform product morphology, and is easy to mass-produce on a large scale.

[0048] In some embodiments, the precursor may be, but is not limited to, Fe. 0.4 Mn 0.595 Nb 0.005 PO4, Fe 0.3 Mn 0.68 Nb 0.01 V 0.01 PO4, Fe 0.35 Mn 0.63 Nb 0.015 Ti 0.005 PO4, Fe 0.1 Mn 0.88 Nb 0.01 Mo 0.01 PO4, Fe 0.2 Mn 0.78 Nb 0.01 V 0.01PO4.

[0049] In some embodiments, step S11 includes processing the precursor Fe X Mn 1-X-Y {M} Y The iron and manganese sources are placed in a reaction vessel according to the proportion shown in PO4. Deionized water and phosphoric acid are added to dissolve them, and the mixture is stirred and mixed continuously for 1 to 4 hours (e.g., 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours). Then, the solution obtained by stirring and mixing is filtered to remove insoluble matter to obtain the first solution.

[0050] In some embodiments, in step S11, the iron source is selected from at least one of metallic iron (such as iron powder), ferrous oxide, and ferrous carbonate. That is, the iron source can be any one of metallic iron, ferrous oxide, and ferrous carbonate, or any combination of two or more of metallic iron, ferrous oxide, and ferrous carbonate.

[0051] In some embodiments, in step S11, the manganese source is selected from at least one of metallic manganese (such as manganese powder), manganese sulfide, and manganese sulfide. That is, the manganese source can be any one of metallic manganese, manganese sulfide, and manganese sulfide, or any combination of two or more of metallic manganese, manganese sulfide, and manganese sulfide.

[0052] In some embodiments, in step S11, the ratio of the amount of phosphoric acid to the sum of the amounts of the iron source, manganese source, and doped metal source is 2.5 to 4 (e.g., 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, or 4).

[0053] In some embodiments, in step S12, the median particle size D50 of the doped metal source is 100 nm to 400 nm (e.g., 100 nm, 200 nm, 300 nm, 370 nm, 380 nm or 400 nm).

[0054] In some embodiments, in step S13, the organic solvent is selected from at least one of ethanol, methanol, and acetone.

[0055] In some embodiments, the mass ratio of the organic solvent in step S13 to the deionized water in step S11 is (0.5 to 10):1. Specifically, the mass of the organic solvent in step S13 is 0.5 times, 1 times, 2 times, 3 times, 4 times, 5 times, 6 times, 7 times, 8 times, 9 times, or 10 times the mass of the deionized water in step S11.

[0056] In some embodiments, in step S14, the drying temperature is 50°C to 80°C (e.g., 50°C to 60°C, 60°C to 70°C, or 70°C to 80°C), and the drying time is 2 hours to 10 hours (e.g., 2 hours to 3 hours, 3 hours to 4 hours, 4 hours to 5 hours, 5 hours to 6 hours, 6 hours to 7 hours, 7 hours to 8 hours, 8 hours to 9 hours, or 9 hours to 10 hours).

[0057] In some embodiments, in step S14, the sintering atmosphere is an oxygen atmosphere or an air atmosphere, the sintering temperature is 400°C to 700°C (e.g., 400°C to 500°C, 500°C to 600°C, or 600°C to 700°C), and the sintering time is 2 hours to 10 hours (e.g., 2 hours to 3 hours, 3 hours to 4 hours, 4 hours to 5 hours, 5 hours to 6 hours, 6 hours to 7 hours, 7 hours to 8 hours, 8 hours to 9 hours, or 9 hours to 10 hours).

[0058] A second aspect of this application provides a precursor for a lithium-ion battery cathode material, the precursor having the expression Fe... X Mn 1-X-Y {M} Y PO4, where 0.1 ≤ X ≤ 0.4, 0.005 ≤ Y ≤ 0.02, and M includes Nb, and M may also optionally include at least one of Mo, Ti, and V. This precursor can be obtained using the method for preparing the precursor of the lithium-ion battery cathode material provided in the first aspect of this application, but is not limited thereto.

[0059] In some embodiments, the precursor includes secondary aggregates formed from primary particles, the median particle size D50 of which is 1 μm to 50 μm (e.g., 1 μm to 10 μm, 10 μm to 20 μm, 20 μm to 23 μm, 23 μm to 30 μm, 30 μm to 40 μm, or 40 μm to 50 μm).

[0060] A third aspect of this application provides a method for preparing a lithium-ion battery cathode material, wherein the lithium-ion battery cathode material is expressed as Li… Z Fe X Mn 1-X-Y {M} Y The formula is PO4 / C, where 0.1 ≤ X ≤ 0.4, 0.005 ≤ Y ≤ 0.02, 1.005 ≤ Z ≤ 1.05, and M includes Nb. M may also optionally include at least one of Mo, Ti, and V. The preparation method of this lithium-ion battery cathode material includes steps S21 and S22. Depending on different requirements, some steps of the preparation method of the lithium-ion battery cathode material may be omitted or combined.

[0061] Step S21: Provide a precursor for lithium-ion battery cathode material.

[0062] In some embodiments, the precursor in step S21 may be a precursor obtained by the method for preparing the precursor of the lithium-ion battery cathode material described in the first aspect of this application.

[0063] In another embodiment, step S21 may include some or all of steps S11 to S14 in the method for preparing the precursor of the lithium-ion battery cathode material described in the first aspect of this application.

[0064] In some embodiments, step S21 may not include steps S11 to S14 as described above, but instead directly provides a value with the expression Fe. X Mn 1-X-Y {M} Y The precursor of PO4, wherein 0.1≤X≤0.4, 0.005≤Y≤0.02, M includes Nb, and M may also optionally include at least one of Mo, Ti and V.

[0065] Step S22: The precursor, lithium source and carbon source are nano-sized, dried, sintered and crushed to obtain the cathode material for lithium-ion batteries.

[0066] Specifically, in step S22, the ratio of the amount of lithium source and precursor, calculated as metal elements, is as shown in the expression for lithium-ion battery cathode materials.

[0067] In the above-mentioned preparation method of lithium-ion battery cathode material, on the one hand, the doping element has good catalytic performance, which can improve the graphitization degree of carbon source during carbonization, reduce the amount of carbon source used and reduce the presence of free carbon, and can also improve the compaction density of lithium-ion battery cathode material; on the other hand, the doping element in lithium-ion battery cathode material Li Z Fe X Mn 1-X-Y {M} Y In PO4 / C, excess lithium forms lithides (LiNbO3, Li2MoO4, Li4Ti5O3). 12 Lithium-ion conductors (such as Li3VO4) can further improve the lithium-ion conductivity of lithium-ion battery cathode materials, thereby enhancing their electrochemical performance. Furthermore, the aforementioned methods for preparing lithium-ion battery cathode materials effectively reduce environmental impact during the preparation process, providing a pollution-free and sustainable green process route for subsequent large-scale production.

[0068] In some embodiments, in step S22, the lithium source is selected from at least one of lithium carbonate and lithium hydroxide.

[0069] In some embodiments, in step S22, the carbon source is selected from at least one of glucose, sucrose, and polyethylene glycol.

[0070] In some embodiments, in step S22, the weight ratio of the carbon source to the precursor is 0.06 to 0.12 (e.g., 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, or 0.12).

[0071] In some embodiments, in step S22, the median particle size D50 of the particles obtained after nano-sizing is 250nm to 500nm (e.g., 250nm to 300nm, 300nm to 340nm, 340nm to 350nm, 350nm to 360nm, 360nm to 380nm, or 380nm to 400nm).

[0072] In some embodiments, in step S22, the sintering atmosphere is a nitrogen or argon atmosphere, the highest platform temperature is 650°C to 720°C (e.g., 650°C, 660°C, 670°C, 680°C, 690°C, 700°C, 710°C, or 720°C), and the highest platform holding time is 4 hours to 8 hours (e.g., 4 hours, 5 hours, 6 hours, 7 hours, or 8 hours).

[0073] The fourth aspect of this application provides a lithium-ion battery cathode material. The formula for this lithium-ion battery cathode material is Li… Z Fe X Mn 1-X-Y {M} Y The formula is PO4 / C, where 0.1 ≤ X ≤ 0.4, 0.005 ≤ Y ≤ 0.02, 1.005 ≤ Z ≤ 1.05, and M includes Nb. M may also optionally include at least one of Mo, Ti, and V. This lithium-ion battery cathode material can be obtained using the method for preparing lithium-ion battery cathode materials provided in the third aspect of this application, but is not limited thereto.

[0074] In some embodiments, the median particle size D50 of the primary particles of the lithium-ion battery cathode material is 0.5 μm to 1.5 μm (e.g., 0.5 μm to 0.8 μm, 0.8 μm to 1.0 μm, 1.0 μm to 1.2 μm, 1.2 μm to 1.4 μm, or 1.4 μm to 1.5 μm).

[0075] In some embodiments, the compaction density of the lithium-ion battery cathode material is 2.35 g / cm³ at 200 MPa. 3 Up to 2.50 g / cm 3 (e.g., 2.35g / cm) 3 Up to 2.4 g / cm 3 2.4g / cm 3 Up to 2.43 g / cm 3 2.43 g / cm 3 Up to 2.45 g / cm 3 or 2.45g / cm3 Up to 2.5g / cm 3 ).

[0076] In some embodiments, the carbon content of the lithium-ion battery cathode material is 1.1 wt% to 1.8 wt% (e.g., 1.1 wt% to 1.3 wt%, 1.3 wt% to 1.5 wt%, 1.5 wt% to 1.7 wt%, or 1.7 wt% to 1.8 wt%).

[0077] In some embodiments, the porosity of the lithium-ion battery cathode material, as determined by gas adsorption, is 5% to 25% (e.g., 5% to 10%, 10% to 15%, 15% to 20%, or 20% to 25%).

[0078] This application provides a positive electrode sheet. The electrode sheet includes a current collector and a positive electrode active material layer located on the current collector. The positive electrode active material layer comprises a lithium-ion battery positive electrode material obtained by the method for preparing lithium-ion battery positive electrode material as described in the third aspect of this application. Alternatively, the positive electrode active material layer comprises a lithium-ion battery positive electrode material as described in the fourth aspect of this application.

[0079] The current collector may be, for example, aluminum foil, copper foil, nickel-plated steel strip, etc., but is not limited to these. The positive electrode active material layer also includes conductive agents, binders, etc. The conductive agent may be selected from one or more of conductive carbon black (model: Super-P), acetylene black, Ketjen black, graphene, and carbon nanotubes, but is not limited to these. The binder may be selected from one or more of fluorinated resins and / or polyolefin compounds, such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and styrene-butadiene rubber, but is not limited to these.

[0080] This application provides a battery in a sixth aspect. The battery includes a positive electrode, a negative electrode, and a separator located between the positive and negative electrode. The positive electrode is the same as the positive electrode provided in the fifth aspect of this application. The separator has electrical insulation and liquid retention properties, and is, for example, a composite membrane formed by welding or bonding a wettable polyolefin microporous membrane to polyethylene, polypropylene, modified polyethylene felt, modified polypropylene felt, ultrafine glass fiber felt, vinylon felt, or nylon felt, but is not limited thereto.

[0081] The present application will be further described below with reference to specific embodiments and comparative examples.

[0082] Example 1

[0083] This embodiment provides a precursor Fe 0.4 Mn 0.595 Nb 0.005 PO4 and Li, a lithium-ion battery cathode material prepared from this precursor 1.005 Fe 0.4 Mn 0.595 Nb 0.005PO4 / C. Precursor Fe 0.4 Mn 0.595 Nb 0.005 PO4 is obtained according to steps (1) to (5). Lithium-ion battery cathode material Li 1.005 Fe 0.4 Mn 0.595 Nb 0.005 PO4 / C is obtained by following steps (1) to (6).

[0084] Step (1): Based on the metal element, according to the precursor Fe 0.4 Mn 0.595 Nb 0.005 The ratio of Fe to Mn atoms shown in PO4 was determined by placing iron powder and manganese powder in a reaction vessel, adding deionized water and phosphoric acid to dissolve them. The amount of phosphoric acid was 2.5 times the sum of the amounts of iron powder, manganese powder, and niobium oxide. The mixture was stirred and mixed for 1 hour.

[0085] Step (2): Filter the solution obtained in step (1) to remove insoluble matter and obtain a solution (also referred to as the first solution in the above text).

[0086] Step (3): Based on the metal element, according to the precursor Fe 0.4 Mn 0.595 Nb 0.005 The ratio of Fe, Mn, and Nb atoms shown in PO4 was used to add nano-sized niobium oxide to the solution obtained in step (2) and mix thoroughly for 2 hours. The median particle size of the niobium oxide particles was 100 nm.

[0087] Step (4): Ethanol is slowly added to the solution system obtained in step (3) (also referred to as the second solution above), and a precipitate is formed. The mass of ethanol added is 0.5 times the mass of deionized water in step (1).

[0088] Step (5): The precipitate obtained in step (4) is washed, dried at 50°C for 10 hours, and then sintered at 400°C in air for 10 hours to obtain the precursor Fe. 0.4 Mn 0.595 Nb 0.005 PO4. The median particle size of this precursor was 23 μm, as measured by a laser particle size analyzer.

[0089] Step (6): Based on the metal element, according to the lithium-ion battery cathode material Li 1.005 Fe 0.4 Mn 0.595 Nb 0.005 Li and Fe shown in PO4 / C 0.4 Mn 0.595 Nb0.005 The ratio of the number of atoms in PO4 will affect the precursor Fe. 0.4 Mn 0.595 Nb 0.005 PO4, lithium carbonate, and sucrose were nano-milled to obtain a slurry with a particle size of 250 nm and a sucrose weight of 0.06 times that of the precursor. The slurry was dried using a spray gun and sintered under a nitrogen atmosphere with a multi-plateau temperature profile (highest plateau temperature 650℃, held at this temperature for 8 hours). The slurry was then crushed to obtain the lithium-ion battery cathode material Li. 1.005 Fe 0.4 Mn 0.595 Nb 0.005 PO4 / C.

[0090] like Figure 1 As shown, the precursor Fe obtained in Example 1 0.4 Mn 0.595 Nb 0.005 The PO4 material is uniformly dispersed, consisting of secondary aggregates formed by primary particles with a particle size of about 30 nm.

[0091] like Figure 2 As shown, the lithium-ion battery cathode material Li obtained in Example 1 1.005 Fe 0.4 Mn 0.595 Nb 0.005 PO4 / C has a smooth surface and a well-balanced particle size distribution. Testing has shown that Li is a suitable cathode material for lithium-ion batteries. 1.005 Fe 0.4 Mn 0.595 Nb 0.005 The carbon content in PO4 / C is 1.56%, and the median particle size (D50) of the powder is 1.2 μm. The Li-ion battery cathode material, measured by gas adsorption, exhibits these properties. 1.005 Fe 0.4 Mn 0.595 Nb 0.005 The porosity of PO4 / C is 10.21%.

[0092] like Figure 3 As shown, the lithium-ion battery cathode material Li obtained in Example 1 1.005 Fe 0.4 Mn 0.595 Nb 0.005 The XRD pattern of PO4 / C shows a standard LiMPO4 (PDF 77-0178) structure with no obvious impurities.

[0093] like Figure 4 As shown, the lithium-ion battery cathode material Li obtained in Example 1 1.005 Fe 0.4 Mn0.595 Nb 0.005 PO4 / C powder has an electrical conductivity of 7.1 × 10⁻⁶ at 200 MPa. -2 S / cm, compacted density is 2.43 g / cm³ 3 .

[0094] like Figure 5 As shown, the lithium-ion battery cathode material Li obtained in Example 1 1.005 Fe 0.4 Mn 0.595 Nb 0.005 The PO4 / C material has a smooth interface with no obvious internal voids. It is evident that, under the condition of holding at a maximum temperature of 650℃ for 8 hours, this material exhibits a high compaction density. This is attributed to the presence of niobium oxide in this example, which reduces the internal porosity of the powder material during sintering, thereby increasing the material's density.

[0095] like Figure 6 As shown, the lithium-ion battery cathode material Li obtained in Example 1 1.005 Fe 0.4 Mn 0.595 Nb 0.005 The charge-discharge curves of PO4 / C powder show a 0.2C discharge capacity of 151.5 mAh / g and a coulombic efficiency of 98.0%, demonstrating good electrochemical activity.

[0096] Example 2

[0097] This embodiment provides a precursor Fe 0.3 Mn 0.68 Nb 0.01 V 0.01 PO4 and Li, a lithium-ion battery cathode material prepared from this precursor 1.05 Fe 0.3 Mn 0.68 Nb 0.01 V 0.01 PO4 / C. Precursor Fe 0.3 Mn 0.68 Nb 0.01 V 0.01 PO4 is obtained according to steps (1) to (5). Lithium-ion battery cathode material Li 1.05 Fe 0.3 Mn 0.68 Nb 0.01 V 0.01 PO4 / C is obtained by following steps (1) to (6).

[0098] Step (1): Based on the metal element, according to the precursor Fe 0.3 Mn 0.68 Nb0.01 V 0.01 The ratio of Fe and Mn atoms shown in PO4 was determined by placing ferrous oxide and manganese oxide in a reaction vessel, adding deionized water and phosphoric acid to dissolve them. The amount of phosphoric acid was four times the sum of the amounts of ferrous oxide, manganese oxide, niobium oxide, and vanadium oxide. The mixture was stirred and mixed continuously for 1.5 hours.

[0099] Step (2): Filter the solution obtained in step (1) to remove insoluble matter and obtain a solution (also referred to as the first solution in the above text).

[0100] Step (3): Based on the metal element, according to the precursor Fe 0.3 Mn 0.68 Nb 0.01 V 0.01 The ratio of the number of Fe, Mn, Nb, and V atoms shown in PO4 is used to determine the atomic ratio. Niobium oxide and vanadium oxide are nano-sized and added to the solution obtained in step (2), then stirred thoroughly for 2 hours. The median particle size of the niobium oxide and vanadium oxide particles is 400 nm.

[0101] Step (4): Slowly add methanol to the solution system obtained in step (3) (also referred to as the second solution above) to produce a precipitate. The amount of methanol added is 10 times the mass ratio of the deionized water in step (1).

[0102] Step (5): The precipitate obtained in step (4) is washed, dried at 80°C for 2 hours, and then sintered at 700°C for 2 hours in air atmosphere to obtain the precursor Fe. 0.3 Mn 0.68 Nb 0.01 V 0.01 PO4. The median particle size of this precursor was 50 μm, as measured by a laser particle size analyzer.

[0103] Step (6): Based on the metal element, according to the lithium-ion battery cathode material Li 1.05 Fe 0.3 Mn 0.68 Nb 0.01 V 0.01 Li and Fe shown in PO4 / C 0.3 Mn 0.68 Nb 0.01 V 0.01 The ratio of the number of atoms in PO4 will affect the precursor Fe. 0.3 Mn 0.68 Nb 0.01 V 0.01PO4, lithium hydroxide, glucose, and PEG were nano-milled to obtain a slurry with a particle size of 400 nm and a sucrose weight of 0.12 times that of the precursor. The slurry was dried using a spray gun and sintered under a nitrogen atmosphere with a multi-plateau temperature profile (highest plateau temperature 720℃, held at this temperature for 4 hours). The slurry was then crushed to obtain the lithium-ion battery cathode material Li. 1.05 Fe 0.3 Mn 0.595 Nb 0.01 V 0.01 PO4 / C.

[0104] Example 3

[0105] This embodiment provides a precursor Fe 0.35 Mn 0.63 Nb 0.015 Ti 0.005 PO4 and Li, a lithium-ion battery cathode material prepared from this precursor 1.03 Fe 0.35 Mn 0.63 Nb 0.015 Ti 0.005 PO4 / C. Precursor Fe 0.35 Mn 0.63 Nb 0.015 Ti 0.005 PO4 is obtained from steps (1) to (5). Li is the cathode material for lithium-ion batteries. 1.03 Fe 0.35 Mn 0.63 Nb 0.015 Ti 0.005 PO4 / C is obtained by following steps (1) to (6).

[0106] Step (1): Based on the metal element, according to the precursor Fe 0.35 Mn 0.63 Nb 0.015 Ti 0.005 The ratio of Fe to Mn atoms shown in PO4 was determined by placing ferrous oxide, manganese oxide, and manganese carbonate in a reaction vessel, adding deionized water and phosphoric acid to dissolve them. The amount of phosphoric acid was 3.2 times the sum of the amounts of ferrous oxide, manganese oxide, niobium oxide, and titanium oxide, and the mixture was stirred continuously for 1.5 hours.

[0107] Step (2): Filter the solution obtained in step (1) to remove insoluble matter and obtain a solution (also referred to as the first solution in the above text).

[0108] Step (3): Based on the metal element, according to the precursor Fe 0.35 Mn 0.63 Nb 0.015 Ti0.005 The ratio of Fe, Mn, Nb, and Ti atoms shown in PO4 was used to add niobium oxide and titanium oxide, which were nano-sized, to the solution prepared in step (2) and stirred thoroughly for 2 hours. The median particle size of the niobium oxide and titanium oxide particles was 380 nm.

[0109] Step (4): Acetone is slowly added to the solution system obtained in step (3) (also referred to as the second solution above), and a precipitate is formed. The amount of acetone added is 8 times the mass ratio of the deionized water in step (1).

[0110] Step (5): The precipitate obtained in step (4) is washed, dried at 75°C for 2 hours, and then sintered at 600°C for 3 hours in an oxygen atmosphere to obtain the precursor Fe. 0.35 Mn 0.63 Nb 0.015 Ti 0.005 PO4. The median particle size of this precursor was 30 μm, as measured by a laser particle size analyzer.

[0111] Step (6): Based on the metal element, according to the lithium-ion battery cathode material Li 1.03 Fe 0.35 Mn 0.63 Nb 0.015 Ti 0.005 Li and Fe shown in PO4 / C 0.35 Mn 0.63 Nb 0.015 Ti 0.005 The ratio of the number of atoms in PO4 will affect the precursor Fe. 0.35 Mn 0.63 Nb 0.015 Ti 0.005 PO4, lithium carbonate, lithium hydroxide, glucose, and sucrose were nano-milled to obtain a slurry with a particle size of 340 nm and a sucrose weight of 0.09 times that of the precursor. The slurry was dried using a spray gun and sintered under a nitrogen atmosphere with a multi-plateau temperature profile (highest plateau temperature 710℃, held at this temperature for 5 hours). The slurry was then crushed to obtain the lithium-ion battery cathode material Li. 1.03 Fe 0.35 Mn 0.63 Nb 0.015 Ti 0.005 PO4 / C.

[0112] Example 4

[0113] This embodiment provides a precursor Fe 0.1 Mn 0.88 Nb 0.01 Mo 0.01PO4 and Li, a lithium-ion battery cathode material prepared from this precursor 1.023 Fe 0.1 Mn 0.88 Nb 0.01 Mo 0.01 PO4 / C. Precursor Fe 0.1 Mn 0.88 Nb 0.01 Mo 0.01 PO4 is obtained according to steps (1) to (5). Lithium-ion battery cathode material Li 1.023 Fe 0.1 Mn 0.88 Nb 0.01 Mo 0.01 PO4 / C is obtained by following steps (1) to (6).

[0114] Step (1): Based on the metal element, according to the precursor Fe 0.1 Mn 0.88 Nb 0.01 Mo 0.01 The ratio of Fe and Mn atoms shown in PO4 was determined by placing ferrous oxide and manganese in a reaction vessel, adding deionized water and phosphoric acid to dissolve them. The amount of phosphoric acid was 3.5 times the sum of the amounts of ferrous oxide, manganese, niobium oxide, and molybdenum oxide, and the mixture was stirred and mixed for 2 hours.

[0115] Step (2): Filter the solution obtained in step (1) to remove insoluble matter and obtain a solution (also referred to as the first solution in the above text).

[0116] Step (3): Based on the metal element, according to the precursor Fe 0.1 Mn 0.88 Nb 0.01 Mo 0.01 The ratio of Fe, Mn, Nb, and Mo atoms shown in PO4 was used to add niobium oxide and molybdenum oxide, which were nano-sized, to the solution prepared in step (2) and stirred thoroughly for 2 hours. The median particle size of the niobium oxide and molybdenum oxide particles was 400 nm.

[0117] Step (4): Ethanol and methanol are slowly added to the solution system obtained in step (3) (also referred to as the second solution above), and a precipitate is formed. The amount of ethanol and methanol added is 10 times the mass ratio of deionized water in step (1).

[0118] Step (5): The precipitate obtained in step (4) is washed, dried at 80°C for 2 hours, and then sintered at 700°C for 2 hours in an oxygen atmosphere to obtain the precursor Fe. 0.1 Mn 0.88 Nb 0.01 Mo 0.01PO4. The median particle size of this precursor was 50 μm, as measured by a laser particle size analyzer.

[0119] Step (6): Based on the metal element, according to the lithium-ion battery cathode material Li 1.023 Fe 0.1 Mn 0.88 Nb 0.01 Mo 0.01 Li and Fe shown in PO4 / C 0.1 Mn 0.88 Nb 0.01 Mo 0.01 The ratio of the number of atoms in PO4 will affect the precursor Fe. 0.1 Mn 0.88 Nb 0.01 Mo 0.01 PO4, lithium hydroxide, glucose, and PEG were nano-milled to obtain a slurry with a particle size of 400 nm and a sucrose weight of 0.12 times that of the precursor. The slurry was dried using a spray gun and sintered under an argon atmosphere with a multi-platform temperature profile (highest plateau temperature 720℃, held at this temperature for 4 hours). The slurry was then crushed to obtain the lithium-ion battery cathode material Li. 1.023 Fe 0.1 Mn 0.88 Nb 0.01 Mo 0.01 PO4 / C.

[0120] Example 5

[0121] This embodiment provides a precursor Fe 0.2 Mn 0.78 Nb 0.01 V 0.01 PO4 and Li, a lithium-ion battery cathode material prepared from this precursor 1.1 Fe 0.2 Mn 0.78 Nb 0.01 V 0.01 PO4 / C. Precursor Fe 0.2 Mn 0.78 Nb 0.01 V 0.01 PO4 is obtained according to steps (1) to (5). Lithium-ion battery cathode material Li 1.1 Fe 0.2 Mn 0.78 Nb 0.01 V 0.01 PO4 / C is obtained by following steps (1) to (6).

[0122] Step (1): Based on the metal element, according to the precursor Fe 0.2 Mn 0.78Nb 0.01 V 0.01 The ratio of Fe to Mn atoms shown in PO4 was determined by placing ferrous oxide and manganese oxide in a reaction vessel, adding deionized water and phosphoric acid to dissolve them. The amount of phosphoric acid was 2.9 times the sum of the amounts of ferrous oxide, manganese oxide, niobium oxide, and vanadium oxide. The mixture was stirred and mixed continuously for 1.5 hours.

[0123] Step (2): Filter the solution obtained in step (1) to remove insoluble matter and obtain a solution (also referred to as the first solution in the above text).

[0124] Step (3): Based on the metal element, according to the precursor Fe 0.2 Mn 0.78 Nb 0.01 V 0.01 The ratio of Fe, Mn, Nb, and V atoms shown in PO4 was used to add niobium oxide and vanadium oxide, which were nano-sized, to the solution prepared in step (2) and stirred thoroughly for 2 hours. The median particle size of the niobium oxide and vanadium oxide particles was 370 nm.

[0125] Step (4): Slowly add methanol to the solution system obtained in step (3) (also referred to as the second solution above) to produce a precipitate. The amount of methanol added is 10 times the mass ratio of the deionized water in step (1).

[0126] Step (5): The precipitate obtained in step (4) is washed, dried at 80°C for 2 hours, and then sintered at 700°C for 2 hours in air atmosphere to obtain the precursor Fe. 0.2 Mn 0.78 Nb 0.01 V 0.01 PO4. The median particle size of this precursor was 50 μm, as measured by a laser particle size analyzer.

[0127] Step (6): Based on the metal element, according to the lithium-ion battery cathode material Li 1.1 Fe 0.2 Mn 0.78 Nb 0.01 V 0.01 Li and Fe shown in PO4 / C 0.2 Mn 0.78 Nb 0.01 V 0.01 The ratio of the number of atoms in PO4 will affect the precursor Fe. 0.2 Mn 0.78 Nb 0.01 V 0.01PO4, lithium hydroxide, glucose, and PEG were nano-milled to obtain a slurry with a particle size of 400 nm and a sucrose weight of 0.12 times that of the precursor. The slurry was dried using a spray gun and sintered under a nitrogen atmosphere with a multi-plateau temperature profile (highest plateau temperature 720℃, held at this temperature for 4 hours). The slurry was then crushed to obtain the lithium-ion battery cathode material Li. 1.1 Fe 0.2 Mn 0.78 Nb 0.01 V 0.01 PO4 / C.

[0128] Comparative Example 1

[0129] The dopant element Nb was removed from steps (1) and (3) of Example 1, and everything else remained the same as in Example 1, thus obtaining the precursor Fe. 0.4 Mn 0.6 PO4 and Li, a lithium-ion battery cathode material prepared from this precursor 1.005 Fe 0.4 Mn 0.6 PO4 / C.

[0130] like Figure 7 As shown in Figures (a) and (b), the lithium-ion battery cathode material obtained in Comparative Example 1 has poor internal density and an insufficiently smooth surface. The porosity of the material was determined to be 31.56% by gas adsorption.

[0131] Comparative Example 2

[0132] In step (6) of Example 1, the highest platform temperature of 650°C was replaced with 550°C, and everything else remained the same as in Example 1, thus obtaining the precursor Fe. 0.4 Mn 0.595 Nb 0.005 PO4 and Li, a lithium-ion battery cathode material prepared from this precursor 1.005 Fe 0.4 Mn 0.595 Nb 0.005 PO4 / C.

[0133] Experimental Example - Electrochemical Performance Testing

[0134] Test Samples: Lithium manganese iron phosphate cathode materials obtained in Examples 1 to 5 and Comparative Examples 1 to 2 were fabricated into electrode sheets and assembled into button cells for electrochemical performance testing. The specific process was as follows: First, lithium-ion battery cathode materials, conductive agent acetylene black, and binder polyvinylidene fluoride (PVDF) were thoroughly ground at a mass ratio of 8:1:1. Then, N-methylpyrrolidone (NMP) solvent was added, and the mixture was continuously stirred for 6 hours to disperse it evenly into a slurry. The slurry was then coated onto clean aluminum foil current collector using a scraper. After vacuum drying at 130℃ for 12 hours, electrode sheets with a diameter of 14 mm were punched out using a punching machine and assembled into CR2032 button half-cells in a glove box. At room temperature, the CR2032 button half-cells were charged and discharged within a voltage range of 2.5V to 4.3V and a current density of 34 mA / g. The electrochemical performance test results are shown in Table 1.

[0135] The test results show that the physical and electrochemical performance indicators of the lithium-ion battery cathode material obtained in Comparative Example 1 are significantly different from those in Example 1. Due to the low plateau temperature during the sintering process of Comparative Example 2, the prepared lithium-ion battery cathode material Li... 1.005 Fe 0.4 Mn 0.595 Nb 0.005 PO4 / C has a high carbon content, poor crystallinity, and low initial efficiency.

[0136] Table 1

[0137]

[0138] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of this application should not depart from the spirit and scope of the technical solutions of this application.

Claims

1. A method for preparing a precursor for a lithium-ion battery cathode material, characterized in that, The precursor is expressed as Fe X Mn 1-X-Y {M} Y PO4, where 0.1≤X≤0.4, 0.005≤Y≤0.02, and M includes Nb, and M may also selectively include at least one of Mo, Ti, and V; the preparation method of the precursor of the lithium-ion battery cathode material includes: Iron source, manganese source, deionized water and phosphoric acid are stirred and mixed, and the insoluble matter is removed by filtration to obtain the first solution; The doped metal source is nano-sized and added to the first solution to obtain the second solution; An organic solvent is added to the second solution to obtain a precipitate; and The precipitate was washed, dried, and sintered to obtain the precursor; Wherein, the doped metal source is an oxide of M; and the ratio of the amounts of the iron source, the manganese source and the doped metal source, in terms of metal elements, is the ratio of the number of Fe, Mn and M atoms as shown in the expression for the precursor.

2. The method for preparing the precursor of the lithium-ion battery cathode material as described in claim 1, characterized in that, The iron source is selected from at least one of metallic iron, ferrous oxide, and ferrous carbonate; and / or, the manganese source is selected from at least one of metallic manganese, manganese oxide, and manganese carbonate; and / or, the organic solvent is selected from at least one of ethanol, methanol, and acetone.

3. The method for preparing the precursor of the lithium-ion battery cathode material as described in claim 1, characterized in that, In the step of stirring and mixing the iron source, the manganese source, the deionized water, and the phosphoric acid, the stirring and mixing time is 1 hour to 4 hours; and / or, the ratio of the amount of phosphoric acid to the sum of the amounts of the iron source, the manganese source, and the doped metal source is 2.5 to 4; and / or, the median particle size D50 of the doped metal source is 100 nm to 400 nm; and / or, the mass ratio of the organic solvent to the deionized water is (0.5~10):

1.

4. The method for preparing the precursor of the lithium-ion battery cathode material as described in claim 1, characterized in that, In the step of drying the precipitate, the drying temperature is 50°C to 80°C and the drying time is 2 hours to 10 hours; in the step of sintering the precipitate, the sintering atmosphere is an oxygen atmosphere or an air atmosphere, the sintering temperature is 400°C to 700°C, and the sintering time is 2 hours to 10 hours.

5. A precursor for a lithium-ion battery cathode material, characterized in that, The precursor is obtained by the preparation method of the lithium-ion battery cathode material according to any one of claims 1 to 4, and the formula of the precursor is Fe. X Mn 1-X-Y {M} Y PO4, where 0.1≤X≤0.4, 0.005≤Y≤0.02, and M includes Nb, and M may also optionally include at least one of Mo, Ti and V.

6. The precursor for the lithium-ion battery cathode material as described in claim 5, characterized in that, The precursor comprises secondary aggregates formed from primary particles, the median particle size D50 of which is 1µm to 50µm.

7. A method for preparing a lithium-ion battery cathode material, characterized in that, The expression for the positive electrode material of the lithium-ion battery is Li Z Fe X Mn 1-X-Y {M} Y PO4 / C, where 0.1≤X≤0.4, 0.005≤Y≤0.02, 1.005≤Z≤1.05, and M includes Nb, and M may also selectively include at least one of Mo, Ti, and V; the preparation method of the lithium-ion battery cathode material includes: The precursor is prepared according to the method for preparing the precursor of the lithium-ion battery cathode material as described in any one of claims 1 to 4, or the precursor of the lithium-ion battery cathode material as described in claim 5 or 6 is provided. The precursor, lithium source, and carbon source are nano-sized, dried, sintered, and crushed to obtain the lithium-ion battery cathode material. Wherein, in terms of metal elements, the ratio of the amount of the lithium source to the amount of the precursor is the ratio of the number of Li atoms to the number of precursor atoms as shown in the expression for the lithium-ion battery cathode material.

8. The method for preparing the lithium-ion battery cathode material as described in claim 7, characterized in that, The lithium source is selected from at least one of lithium carbonate and lithium hydroxide; and / or, the carbon source is selected from at least one of glucose, sucrose and polyethylene glycol, wherein the weight ratio of the carbon source to the precursor is 0.06 to 0.

12.

9. The method for preparing the lithium-ion battery cathode material as described in claim 7, characterized in that, In the step of nano-sizing the precursor, lithium source, and carbon source, the median particle size D50 of the particles obtained after nano-sizing is 250 nm to 500 nm; in the step of sintering the precursor, lithium source, and carbon source, the sintering atmosphere is nitrogen or argon atmosphere, the maximum plateau temperature is 650 °C to 720 °C, and the maximum plateau holding time is 4 hours to 8 hours.

10. A lithium-ion battery cathode material, characterized in that, The lithium-ion battery cathode material is obtained by the preparation method of lithium-ion battery cathode material according to any one of claims 7 to 9, and the formula of the lithium-ion battery cathode material is Li Z Fe X Mn 1-X-Y {M} Y PO4 / C, where 0.1≤X≤0.4, 0.005≤Y≤0.02, 1.005≤Z≤1.05, and M includes Nb, and M may also optionally include at least one of Mo, Ti and V.

11. The lithium-ion battery cathode material as described in claim 10, characterized in that, The median particle size D50 of the primary particles of the lithium-ion battery cathode material is 0.5µm to 1.5µm; and / or, at 200MPa, the compaction density of the lithium-ion battery cathode material is 2.35g / cm³. 3 Up to 2.50 g / cm 3 ; and / or, the carbon content of the lithium-ion battery cathode material is 1.1 wt% to 1.8 wt%; and / or, the porosity of the lithium-ion battery cathode material, as determined by gas adsorption, is 5% to 25%.

12. A positive electrode plate, characterized in that, It includes a current collector and a positive electrode active material layer located on the current collector, wherein the positive electrode active material layer comprises a lithium-ion battery positive electrode material obtained by the preparation method of the lithium-ion battery positive electrode material according to any one of claims 7 to 9; or, the positive electrode active material comprises a lithium-ion battery positive electrode material according to claim 10 or 11.

13. A battery, characterized in that, It includes a positive electrode, a negative electrode, and a separator located between the positive electrode and the negative electrode, wherein the positive electrode is the positive electrode as described in claim 12.

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