Positive electrode material precursor and preparation method thereof, positive electrode material and lithium ion battery

Abstract

The invention provides a positive electrode material precursor and a preparation method thereof, a positive electrode material and a lithium ion battery. The chemical formula of the positive electrode material precursor is NixTiyMez (OH) 2, wherein xlt is greater than or equal to 0.8; 0.95, 0.05 lt, 0.95, 0.05 lt; y < = 0.2, 0 < = z < = 0.01; and Me comprises one or more of Mn, Co, Al, W, Zr, Si, Mg, B, Sr, Ti, Nb and Ta. Ti in the positive electrode material precursor is used as a basic element, and the molar ratio is 0.05 lt; y is less than or equal to 0.2, the interlayer spacing of a subsequently prepared positive electrode material can be expanded through the interaction of Ti < 4 + > and crystal lattices, more interlayer active sites are released, and different from the conditions that the interlayer spacing is relatively narrow, the interlayer active sites are few and are not activated during low doping of a lithium nickelate or doped lithium nickelate system, the capacity loss possibly caused by the fact that the Ti element occupies part of nickel sites is effectively compensated, and the performance of the lithium nickelate battery is improved. Meanwhile, the specific capacity and the rate capability of the positive electrode material are improved.

Description

Technical Field

[0001] This application belongs to the technical field of cathode materials for batteries, and particularly relates to a cathode material precursor, a preparation method thereof, a cathode material, and a lithium-ion battery. Background Art

[0002] Lithium-ion batteries have been widely used in fields such as portable electronic devices, electric vehicles, and large-scale energy storage due to their outstanding advantages such as high energy density, long cycle life, and low self-discharge rate. With the rapid development of various application fields, the performance requirements for lithium-ion batteries are also increasing day by day. Especially in high-power application scenarios, such as rapid acceleration, climbing, and instantaneous high-power discharge operations of electric vehicles, there are strict requirements for the high-power performance of the batteries.

[0003] As a key component of lithium-ion batteries, the performance of the cathode material largely determines the overall performance of the battery. Therefore, the research and development of high-performance cathode material precursors have become a research hotspot and key direction in the current lithium-ion battery field. Summary of the Invention

[0004] To solve the above problems, this application provides a cathode material precursor, a preparation method thereof, a cathode material, and a lithium-ion battery, which synergistically improve the cycle stability and specific capacity.

[0005] In the first aspect, an embodiment of this application provides a cathode material precursor, and the chemical formula of the cathode material precursor is Ni 3 , 3 , 3 , 2 , 3 , z , 2 ,

[0006] , Ti y Me z (OH)2; where 0.8 ≤ x < 0.95, 0.05 < y ≤ 0.2, 0 ≤ z ≤ 0.01; Me includes one or more of Mn, Co, Al, W, Zr, Si, Mg, B, Sr, Ti, Nb, and Ta.

[0006] According to the embodiment of the first aspect of this application, the cathode material precursor satisfies at least one of the following conditions: (1) The precursor includes spherical secondary particles, and the secondary particles include multiple primary particles; (2) The D50 of the precursor is 2.0 μm to​​​​​​​​​​​(6) The cross-sectional porosity of the precursor is ≤15%; optionally, the cross-sectional porosity is ≤10%, and further optionally, the cross-sectional porosity is ≤8%; (7) Ni x Ti y Me z In (OH)2, 0.1≤y≤0.2.

[0007] According to an embodiment of the first aspect of this application, the X-ray powder diffraction pattern of the cathode material precursor satisfies the following: the full width at half maximum (FWHM) of the diffraction peaks corresponding to the (001) crystal plane is 0.2~0.9°; optionally, the FWHM of the diffraction peaks corresponding to the (001) crystal plane is 0.2~0.5°. And / or, the full width at half maximum (FWHM) of the diffraction peaks corresponding to the (100) crystal plane is 0.2~0.6°; optionally, the full width at half maximum (FWHM) of the diffraction peaks corresponding to the (100) crystal plane is 0.2~0.4°. And / or, the full width at half maximum (FWHM) of the diffraction peaks corresponding to the (101) crystal plane is 0.3~0.9°; optionally, the full width at half maximum (FWHM) of the diffraction peaks corresponding to the (101) crystal plane is 0.3~0.6°. Among them, the diffraction peak corresponding to the (001) crystal plane is at a diffraction angle of 2. The diffraction peaks are located at 17°-21°; the diffraction peaks corresponding to the (100) crystal plane are at diffraction angles of 2° and 3°. The diffraction peaks at 32°-35°; the diffraction peaks corresponding to the (101) crystal plane are at diffraction angles 2° and 35°. The diffraction peak is located at 37°-41°.

[0008] Secondly, embodiments of this application provide a method for preparing a cathode material precursor as described in the first aspect embodiment, comprising the following steps: preparing a metal salt solution, a precipitant solution, and a complexing agent solution respectively; mixing the solvent, precipitant solution, and complexing agent solution to obtain a base liquid; simultaneously introducing the metal salt solution, precipitant solution, and complexing agent solution into the base liquid to perform a co-precipitation reaction, thereby obtaining a precursor slurry; and performing post-processing on the precursor slurry to obtain a cathode material precursor.

[0009] According to an embodiment of the second aspect of this application, the preparation method satisfies at least one of the following conditions: a. The coprecipitation reaction process specifically includes: simultaneously introducing a metal salt solution, a precipitant solution, and a complexing agent solution into the bottom liquid to carry out coprecipitation reaction I-1 to obtain seed crystals; mixing the seed crystals, the precipitant solution, and the complexing agent solution to obtain a reaction solution; and continuing to introduce a metal salt solution, a precipitant solution, and a complexing agent solution into the reaction solution to carry out coprecipitation reaction I-2 to obtain a precursor slurry; b. The coprecipitation reaction process includes: simultaneously introducing a metal salt solution, a precipitant solution, and a complexing agent solution into the bottom liquid to carry out coprecipitation reaction II until the reaction slurry reaches the upper limit of the reactor volume, and then concentrating to obtain a precursor slurry, wherein the stirring speed during the concentration process is less than the stirring speed during coprecipitation reaction II, and the pH value during the concentration process is... c. The post-treatment includes: sequentially performing solid-liquid separation, washing, drying, and sieving on the precursor slurry to obtain the cathode material precursor; d. The raw materials for the metal salt solution include nickel salt and titanium salt, and optionally, the raw materials for the metal salt solution also include Me salt, where Me is selected from at least one of Mn, Co, Al, W, Zr, Si, Mg, B, Sr, Ti, Nb, and Ta; e. The precipitant includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, or potassium carbonate; f. The complexing agent includes at least one of ammonia, ammonium bicarbonate, ammonium carbonate, citric acid, sodium citrate, ammonium citrate, oxalic acid, or ammonium oxalate; g. The total mass concentration of metal ions in the metal salt solution is 110~130 g / L; h. The mass fraction of solute in the precipitant solution is 18~22 wt%; i. The mass fraction of solute in the complexing agent solution is 9~12 wt%.

[0010] According to the embodiments of the second aspect of the present application, the preparation method satisfies at least one of the following conditions: A. The conditions of the bottom liquid include: the pH of the bottom liquid is 11.0 - 11.6, and / or the concentration of the complexing agent in the bottom liquid is 9 - 13 g / L, and / or the temperature of the bottom liquid is 55 - 65 °C, and / or the stirring speed of the reaction liquid is 400 - 500 r / min; B. The conditions of the coprecipitation reaction I-1 include: the pH of the coprecipitation reaction I-1 is 10.8 - 11.5, and / or the concentration of the complexing agent in the coprecipitation reaction I-1 is 11.0 - 12.0 g / L, and / or the temperature of the coprecipitation reaction I-1 is 55 - 65 °C, and / or the stirring speed of the coprecipitation reaction I-1 is 400 r / min - 450 r / min; C. The conditions of the reaction liquid include: the pH of the reaction liquid is 10.25 - 10.45, and / or the concentration of the complexing agent in the reaction liquid is 4.5 - 5.5 g / L, and / or the temperature of the reaction liquid is 50 - 65 °C, and / or the stirring speed of the reaction liquid is 300 - 450 r / min; D. The conditions of the coprecipitation reaction I-2 include: the pH of the coprecipitation reaction I-2 is 10.40 - 10.65; and / or the concentration of the complexing agent in the coprecipitation reaction I-2 is 6 - 10 g / L; and / or the temperature of the coprecipitation reaction I-2 is 50 - 65 °C; and / or the stirring speed of the coprecipitation reaction I-2 is 100 r / min - 400 r / min; E. The conditions of the coprecipitation reaction II include: the pH of the coprecipitation reaction II is 10.8 - 11.5; and / or the concentration of the complexing agent in the coprecipitation reaction II is 11.0 - 12.0 g / L; and / or the temperature of the coprecipitation reaction II is 55 - 65 °C; and / or the stirring speed of the coprecipitation reaction II is 400 r / min - 450 r / min.

[0011] In the third aspect, the embodiments of the present application provide a cathode material, which is obtained by sintering a cathode material precursor in the embodiments of the first aspect of the present application or a cathode material precursor prepared by the preparation method in the embodiments of the second aspect of the present application with a lithium source.

[0012] In the fourth aspect, the embodiments of the present application provide a lithium-ion battery, which includes the cathode material in the embodiments of the third aspect of the present application.

[0013] In the fifth aspect, the embodiments of the present application provide an electricity-related device, which includes the lithium-ion battery in the embodiments of the fourth aspect of the present application.

[0014] In the cathode material precursor of the present application, Ti is used as a basic element, and the molar ratio is 0.05 < y ≤ 0.2, and it can be achieved through Ti 4+The interaction with the lattice expands the interlayer spacing of the subsequent prepared cathode material, releasing more interlayer active sites, which is different from the situation of lithium nickelate or doped lithium nickelate systems where the interlayer spacing is narrow, the interlayer active sites are few and not activated at low doping, effectively compensating for the capacity loss that may be caused by the occupation of part of the nickel site by Ti element, and at the same time improving the specific capacity and rate performance of the cathode material.

[0015] Compared with the traditional ternary system containing elements such as Co and Mn, the cathode material precursor in the embodiment of the present application can achieve cobalt-free or manganese-free design of the subsequent cathode material through the synergistic effect of high-content Ti and Ni, reducing the dependence on scarce resources such as Co and Mn, relieving part of the resource constraints, and reducing the material preparation cost.

[0016] In summary, when the molar ratio of Ti element is 0.05 < y ≤ 0.2, the capacity, cycle, rate and cost of the material can reach an optimal balance within a certain range, achieving the optimization of the material system while taking into account the performance, and providing more possibilities for the development and innovation of the lithium battery material system. Brief Description of the Drawings

[0017] Figure 1 It is the SEM image of the cathode material precursor provided in Embodiment 1 of the present application; Figure 2 It is the SEM image of the cathode material precursor provided in Embodiment 3 of the present application; Figure 3 It is the SEM image of the cross-section of the cathode material precursor provided in Embodiment 3 of the present application; Figure 4 It is the XRD pattern of the cathode material precursor provided in Embodiment 3 of the present application. Detailed Description of the Embodiments

[0018] In order to make the application purpose, technical solution and beneficial technical effects of the present application clearer, the present application will be further described in detail below with reference to embodiments. It should be understood that the embodiments described in this specification are only for explaining the present application and not for limiting the present application.

[0019] For simplicity, the present application only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form a range not explicitly recorded; and any lower limit can be combined with other lower limits to form a range not explicitly recorded, and similarly any upper limit can be combined with any other upper limit to form a range not explicitly recorded. In addition, although not explicitly recorded, each point or single value between the range endpoints is included in this range. Thus, each point or single value can be used as its own lower limit or upper limit to be combined with any other point or single value or with other lower limits or upper limits to form a range not explicitly recorded.

[0020] 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.

[0021] In this application, particle size D50 and average particle size have the same meaning, referring to the particle size corresponding to the cumulative particle size distribution percentage of the cathode material precursor reaching 50%.

[0022] 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 = (D90 - D10) / D50; where: D10: 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); D50: 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); D90: 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 D10, D50, and D90 can be measured using a laser particle size analyzer.

[0023] 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.

[0024] As the core energy storage carrier in the new energy era, the performance of the cathode material of lithium-ion batteries directly determines the energy density and cycle life. Among them, lithium nickel oxide (LiNiO2) has attracted much attention due to its high theoretical capacity and suitable operating voltage. However, its inherent structural defects, including phase transition-induced stress accumulation during cycling, cation mixing caused by nickel ion migration, and interfacial side reactions, reduce the capacity retention and stability during cycling, which seriously limits its practical application.

[0025] In recent years, various approaches have been explored to improve the performance of LiNiO2-based cathode materials, including using alternative electrolytes or optimizing particle morphology and surface design. Among these, the strategy of lattice modification by doping with a small amount (generally no more than 3%) of titanium has gradually become a research hotspot. Its core mechanism lies in the role of titanium ions (Ti ions). 4+ The stable coordination structure formed by Ti and oxygen atoms can effectively suppress lattice distortion, while simultaneously regulating the electronic state distribution of nickel to reduce harmful redox reactions. However, Ti... 4+ While improving structural stability, the chemical inertness of the dopant will irreversibly occupy the active sites, causing the reversible capacity to decrease linearly with increasing doping amount.

[0026] To address the aforementioned issues, this application provides a cathode material precursor and its preparation method, a cathode material, and a lithium-ion battery, which synergistically improve cycle stability and specific capacity.

[0027] In a first aspect, an embodiment of the present application provides a cathode material precursor. The chemical formula of the cathode material precursor is Ni x Ti y Me z (OH)2; wherein, 0.8 ≤ x < 0.95, 0.05 < y ≤ 0.2, 0 ≤ z ≤ 0.01; Me includes one or more of Mn, Co, Al, W, Zr, Si, Mg, B, Sr, Ti, Nb, and Ta.

[0028] In the embodiment of the present application, by controlling the molar ratio of nickel element within the range of 0.8 ≤ x < 0.95, it is possible to ensure that the active nickel element in the precursor has a sufficient content, providing a high-capacity basis for the subsequently prepared cathode material.

[0029] The molar ratio of Ti element in the cathode material precursor is 0.05 < y ≤ 0.2, and its content exceeds the molar content of conventional doping elements. In the present invention, the Ti element is a basic element in the precursor. In the first aspect, the layer spacing of the subsequently prepared cathode material can be expanded through the interaction between Ti 4+ and the crystal lattice, releasing more interlayer active sites, which is different from the case of lithium nickelate or doped lithium nickelate systems with a narrow layer spacing, few interlayer active sites, and unactivated ones at low doping, effectively compensating for the possible capacity loss caused by the Ti element occupying part of the nickel sites, and at the same time improving the specific capacity and rate performance of the cathode material. In the second aspect, when the Ti content is greater than 5%, during the subsequent preparation and cycling of the cathode material, the generation of residual alkali on the material surface can be reduced, avoiding capacity decay caused by side reactions between the residual alkali and the electrolyte; at the same time, Ti 4+ forms a strong Ti-O bond with oxygen atoms to anchor the crystal lattice, effectively preventing the structural collapse during deep de-lithiation. As the Ti doping amount increases, more high-valent Ti 4+ enters the crystal lattice layer, and the migration of Ni 2+ to the interlayer can be inhibited through the charge balance effect, suppressing the lithium-nickel mixing phenomenon, thereby improving the structural stability. In the third aspect, when the Ti content is greater than 5%, the electron conduction path of the cathode material can be optimized, improving the material conductivity, and at the same time further increasing the lattice spacing. The wider lattice channels can reduce the resistance of lithium ion insertion and extraction, promoting the lithium ion de-insertion kinetics, and greatly improving the rate performance of the cathode material. In the fourth aspect, compared with the traditional ternary system containing elements such as Co and Mn, the cathode material precursor in the embodiment of the present application can achieve cobalt-free or manganese-free design of the subsequent cathode material through the synergistic effect of high-content Ti and Ni, reducing the dependence on scarce resources such as Co and Mn, relieving some resource restrictions, and reducing the material preparation cost.

[0030] In summary, when the molar ratio of Ti element is 0.05 < y ≤ 0.2, the capacity, cycle performance, rate performance, and cost of the material can reach an optimal balance within a certain range, optimizing the material system while taking performance into account, providing more possibilities for the development and innovation of lithium-ion battery material systems.

[0031] In the embodiments of the present application, by introducing a Me doping element with a molar ratio of z ≤ 0.01 and utilizing the characteristics of the Me element, the performance of the precursor is regulated without affecting the core performance of the main components Ni and Ti.

[0032] Exemplarily, Me includes Mn and Co elements; or Me includes Mn, Co, and Al elements, and the embodiments of the present application will not list them one by one.

[0033] Exemplarily, the value of x can be any value among 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.9, 0.91, 0.92, 0.93, 0.94, and 0.95 or a range value between any two of them.

[0034] Exemplarily, the value of y can be any value among <0.06, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, and 0.2 or a range value between any two of them.

[0035] Exemplarily, the value of z can be any value among 0, 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, and 0.01 or a range value between any two of them.

[0036] In the embodiments of the present application, the values of x, y, and z in the chemical formula can maintain the valence balance of the chemical formula.

[0037] In some embodiments, the precursor includes quasi-spherical secondary particles, and the secondary particles include a plurality of primary particles.

[0038] The quasi-spherical secondary particles have regular geometric shapes and reasonable particle packing gaps, which can reduce the transmission resistance of the electrolyte between the particles and achieve rapid infiltration.

[0039] In the embodiments of the present application, the primary particles can be nano-sheet primary particles or nano-needle primary particles.

[0040] Nanosheet or needle-like primary particles have a larger specific surface area, which can further increase the contact area between the precursor and the electrolyte. The short axis of the sheet or needle structure provides a convenient channel for ion transport, which can simultaneously shorten the transport path of lithium ions inside the primary particles. This synergizes with Ti to expand the lattice spacing, further improving the rate performance and capacity of subsequent cathode materials.

[0041] In some embodiments, the D50 of the precursor is 2.0 μm to 15.0 μm.

[0042] For example, the volumetric particle size D50 of the precursor is any value or a range between 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, and 15 μm. Optionally, the volumetric particle size D50 of the precursor is 4.0 μm to 12.0 μm.

[0043] In some embodiments, the particle size distribution of the precursor spans from 0.5 to 1.2.

[0044] For example, the particle size distribution of the precursor spans any value from 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, and 1.2, or a range between any two.

[0045] In some embodiments, the specific surface area of ​​the precursor is 20 m². 2 / g~60m 2 / g.

[0046] A larger specific surface area means that the precursor particles have more surface active sites, which can promote the diffusion and migration of ions during sintering.

[0047] For example, the specific surface area of ​​the precursor is 20 m². 2 / g、22m 2 / g、24m 2 / g、26m 2 / g、28m 2 / g、30 m 2 / g、32 m 2 / g、34m 2 / g、35 m 2 / g、36 m 2 / g、38 m 2 / g、40 m 2 / g、42m 2 / g、44 m 2 / g、45 m 2 / g、46 m 2 / g、48m 2 / g、50 m 2 / g、52m 2 / g、54 m 2 / g、55 m 2 / g、56 m 2 / g、58m 2 / g and 60 m 2 Any value in / g or any range between the two.

[0048] In some embodiments, the tap density of the precursor is 1.3 g / cm³. 3 ~2.3g / cm 3 .

[0049] Tap density reflects the compactness of material packing 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 1.3 and 2.3 g / cm³, which can effectively improve the volumetric energy density of the final cathode material.

[0050] For example, the tap density of the precursor is 1.3 g / cm³. 3 1.4g / cm 3 1.5g / cm 3 1.6g / cm 3 1.7g / cm 3 1.8g / cm 3 1.9g / cm 3 2.0g / cm 3 2.1g / cm 3 2.2g / cm 3 and 2.3 g / cm 3 Any value in the range or any value between the two. Optionally, the tapped density is 1.3 g / cm³. 3 ~2.1g / cm 3 .

[0051] In some embodiments, the cross-sectional porosity of the precursor is ≤15%.

[0052] For example, the cross-sectional porosity of the precursor is any value or a range between any two of <1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, and 15%.

[0053] Optionally, the cross-sectional porosity is ≤10%, and further optionally, the cross-sectional porosity is ≤8%.

[0054] A cross-sectional porosity of ≤15% gives the precursor particles good density. In the subsequent electrode preparation process, the spherical secondary particles can be tightly packed. Combined with the low porosity, the electrode compaction density can be further improved. Higher compaction density can increase the content of active material per unit volume and improve the volumetric energy density of lithium-ion batteries.

[0055] In summary, the cathode material precursor in this embodiment has a spherical morphology composed of extremely fine nanosheet-like primary particles. It has low porosity and large specific surface area, which not only ensures full wetting of the electrolyte and significantly reduces the ion migration barrier, thus significantly improving the battery rate performance and energy density, but also enables full utilization of active materials, thereby improving the battery's specific capacity.

[0056] In some embodiments, Ni x Ti y Me z In (OH)2, 0.1≤y≤0.2.

[0057] For example, the value of y can be any value among 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19 and 0.2 or a range between any two.

[0058] According to an embodiment of the first aspect of this application, the X-ray powder diffraction pattern of the cathode material precursor satisfies the following: the full width at half maximum (FWHM) of the diffraction peaks corresponding to the (001) crystal plane is 0.2~0.9°; optionally, the FWHM of the diffraction peaks corresponding to the (001) crystal plane is 0.2~0.5°. And / or, the full width at half maximum (FWHM) of the diffraction peaks corresponding to the (100) crystal plane is 0.2~0.6°; optionally, the full width at half maximum (FWHM) of the diffraction peaks corresponding to the (100) crystal plane is 0.2~0.4°. And / or, the full width at half maximum (FWHM) of the diffraction peaks corresponding to the (101) crystal plane is 0.3~0.9°; optionally, the full width at half maximum (FWHM) of the diffraction peaks corresponding to the (101) crystal plane is 0.3~0.6°; Among them, the diffraction peak corresponding to the (001) crystal plane is at a diffraction angle of 2. The diffraction peaks are located at 17°-21°; the diffraction peaks corresponding to the (100) crystal plane are at diffraction angles of 2° and 3°. The diffraction peaks at 32°-35°; the diffraction peaks corresponding to the (101) crystal plane are at diffraction angles 2° and 35°. The diffraction peak is located at 37°-41°.

[0059] In some embodiments, the X-ray powder diffraction pattern of the cathode material precursor satisfies the following: the full width at half maximum (FWHM) of the diffraction peaks corresponding to the (001) crystal plane is 0.2~0.9°; wherein, the diffraction peaks corresponding to the (001) crystal plane have a diffraction angle of 2°. The diffraction peak is located at 17°-21°.

[0060] For example, the full width at half maximum (FWHM) of the diffraction peak corresponding to the (001) crystal plane can be any value among 0.2°, 0.3°, 0.4°, 0.5°, 0.6°, 0.7°, 0.8°, and 0.9°, or any value in between. Optionally, the FWHM of the diffraction peak corresponding to the (001) crystal plane is 0.2 to 0.5°.

[0061] In some embodiments, the X-ray powder diffraction pattern of the cathode material precursor satisfies the following: the full width at half maximum (FWHM) of the diffraction peak corresponding to the (100) crystal plane is 0.2~0.6°; optionally, the FWHM of the diffraction peak corresponding to the (100) crystal plane is 0.2~0.4°; wherein, the diffraction peak corresponding to the (100) crystal plane is at a diffraction angle of 2°. The diffraction peak is located at 32°-35°. For example, the full width at half maximum (FWHM) of the diffraction peak corresponding to the (100) crystal plane can be any value among 0.2°, 0.3°, 0.4°, 0.5°, and 0.6°, or any value in between. Optionally, the FWHM of the diffraction peak corresponding to the (100) crystal plane is 0.2 to 0.4°.

[0062] In some embodiments, the X-ray powder diffraction pattern of the cathode material precursor satisfies the following: the full width at half maximum (FWHM) of the diffraction peak corresponding to the (101) crystal plane is 0.3~0.9°; optionally, the FWHM of the diffraction peak corresponding to the (101) crystal plane is 0.3~0.6°; wherein, the diffraction peak corresponding to the (101) crystal plane is at a diffraction angle of 2°. The diffraction peak is located at 37°-41°.

[0063] For example, the full width at half maximum (FWHM) of the diffraction peak corresponding to the (101) crystal plane can be any value among 0.3°, 0.4°, 0.5°, 0.6°, 0.7°, 0.8°, and 0.9°, or any value in between. Optionally, the FWHM of the diffraction peak corresponding to the (101) crystal plane is 0.3 to 0.6°.

[0064] Secondly, embodiments of this application provide a method for preparing a cathode material precursor as described in the first aspect embodiment, comprising the following steps: preparing a metal salt solution, a precipitant solution, and a complexing agent solution respectively; mixing the solvent, precipitant solution, and complexing agent solution to obtain a base liquid; simultaneously introducing the metal salt solution, precipitant solution, and complexing agent solution into the base liquid to perform a co-precipitation reaction, thereby obtaining a precursor slurry; and performing post-processing on the precursor slurry to obtain a cathode material precursor.

[0065] The preparation method in this application employs a co-precipitation method to achieve homogeneous co-precipitation of Ni and Ti elements. Through the co-precipitation reaction, Ti and Ni elements are fully mixed in the solution and then co-precipitate, 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.

[0066] In this embodiment, by controlling the process parameters such as reaction temperature, stirring rate, and pH value of co-precipitation reaction I, efficient homogeneous co-deposition of Ti and Ni elements can be ensured.

[0067] In some embodiments, the coprecipitation reaction process specifically includes: simultaneously introducing a metal salt solution, a precipitant solution, and a complexing agent solution into the substrate to carry out coprecipitation reaction I-1 to obtain seed crystals; mixing the seed crystals, the precipitant solution, and the complexing agent solution to obtain a reaction solution; and continuing to introduce a metal salt solution, a precipitant solution, and a complexing agent solution into the reaction solution to carry out coprecipitation reaction I-2 to obtain a precursor slurry.

[0068] In this embodiment, the preparation process of the precursor slurry can be achieved through two co-precipitations. The first co-precipitation yields seed crystals, which can then be used as raw materials to participate in the second co-precipitation reaction. The two co-precipitation reactions are beneficial to increasing the particle size of the cathode material precursor particles.

[0069] In some embodiments, the coprecipitation reaction process includes: simultaneously introducing a metal salt solution, a precipitant solution, and a complexing agent solution into the bottom liquid to carry out coprecipitation reaction II until the reaction slurry reaches the upper limit of the reactor volume and then concentrating to obtain a precursor slurry, wherein the stirring speed during the concentration process is less than the stirring speed of coprecipitation reaction II, and the pH value during the concentration process is less than the pH value of coprecipitation reaction II.

[0070] In the embodiments of this application, the preparation process of the precursor slurry can also be achieved through a single co-precipitation reaction. A single co-precipitation reaction can obtain cathode material precursor particles with smaller particle size. This application is not limited to this.

[0071] In some embodiments, the post-processing includes: sequentially performing solid-liquid separation, washing, drying and sieving on the precursor slurry to obtain the cathode material precursor.

[0072] For example, solid-liquid separation can be achieved through filtration.

[0073] 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 after sieving, the cathode material precursor is obtained.

[0074] In some embodiments, post-processing also includes demagnetization.

[0075] In some embodiments, the raw materials for the metal salt solution include nickel salt and titanium salt. Optionally, the raw materials for the metal salt solution also include Me salt, wherein Me is selected from at least one of Mn, Co, Al, W, Zr, Si, Mg, B, Sr, Ti, Nb and Ta.

[0076] In some embodiments, the precipitant includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, or potassium carbonate.

[0077] In some embodiments, the complexing agent includes at least one of ammonia, ammonium bicarbonate, ammonium carbonate, citric acid, sodium citrate, ammonium citrate, oxalic acid, or ammonium oxalate.

[0078] In some embodiments, the total mass concentration of metal ions in the metal salt solution is 110~130 g / L.

[0079] For example, the total mass concentration of metal ions in the metal salt solution is any value or a range between 110 g / L, 115 g / L, 120 g / L, 125 g / L, and 130 g / L.

[0080] In some embodiments, the mass fraction of the solute in the precipitant solution is 18-22 wt%.

[0081] For example, the mass fraction of the solute in the precipitant solution is any value among 18 wt%, 19 wt%, 20 wt%, 21 wt%, and 22 wt%, or a range between any two.

[0082] In some embodiments, the solute mass fraction of the complexing agent solution is 9-12 wt%.

[0083] For example, the solute mass fraction of the complexing agent solution is any value among 9 wt%, 10 wt%, 11 wt%, and 12 wt%, or a range between any two.

[0084] In some embodiments, the pH of the substrate is 11.0-11.6.

[0085] For example, the pH of the substrate is any value among 11.0, 11.1, 11.2, 11.3, 11.4, 11.5 and 11.6 or a range between any two.

[0086] In some embodiments, the concentration of the complexing agent in the substrate is 9-13 g / L.

[0087] For example, the concentration of the complexing agent in the substrate is any value or a range between 9 g / L, 10 g / L, 11 g / L, 12 g / L and 13 g / L.

[0088] In some embodiments, the temperature of the base liquid is 55-65°C.

[0089] For example, the temperature of the base liquid is any value or a range between any two of 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C, and 65°C.

[0090] In some embodiments, the stirring speed of the base liquid is 400-500 r / min.

[0091] For example, the stirring speed of the base liquid is any value or a range between any two of 400 r / min, 410 r / min, 420 r / min, 430 r / min, 440 r / min, 450 r / min, 460 r / min, 470 r / min, 480 r / min, 490 r / min and 500 r / min.

[0092] In some embodiments, the pH of coprecipitation reaction I-1 is 10.8 to 11.5.

[0093] For example, the pH of coprecipitation reaction I-1 is any value among 10.8, 10.9, 11.0, 11.1, 11.2, 11.3, 11.4 and 11.5 or a range between any two.

[0094] In some embodiments, the concentration of the complexing agent in coprecipitation reaction I-1 is 11.0-12.0 g / L.

[0095] For example, the concentration of the complexing agent in coprecipitation reaction I-1 is any value or a range between 11.0 g / L, 11.1 g / L, 11.2 g / L, 11.3 g / L, 11.4 g / L, 11.5 g / L, 11.6 g / L, 11.7 g / L, 11.8 g / L, 11.9 g / L, and 12.0 g / L.

[0096] In some embodiments, the temperature of coprecipitation reaction I-1 is 55-65°C.

[0097] For example, the temperature of coprecipitation reaction I-1 is any value or a range between any two of 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C, and 65°C.

[0098] In some embodiments, the stirring speed for coprecipitation reaction I-1 is 400 r / min to 450 r / min.

[0099] For example, the stirring speed of coprecipitation reaction I-1 is any value or a range between 400 r / min, 410 r / min, 420 r / min, 430 r / min, 440 r / min and 450 r / min.

[0100] In some embodiments, the pH of the reaction solution is 10.25-10.45.

[0101] For example, the pH of the reaction solution is any value among 10.25, 10.30, 10.35, 10.40, and 10.45, or a range between any two.

[0102] In some embodiments, the concentration of the complexing agent in the reaction solution is 4.5~5.5 g / L.

[0103] For example, the concentration of the complexing agent in the reaction solution is any value or a range between any two of 4.5 g / L, 4.6 g / L, 4.7 g / L, 4.8 g / L, 4.9 g / L, 5.0 g / L, 5.1 g / L, 5.2 g / L, 5.3 g / L, 5.4 g / L, and 5.5 g / L.

[0104] In some embodiments, the temperature of the reaction solution is 50-65°C.

[0105] For example, the temperature of the reaction solution is any value or a range between any two of 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.

[0106] In some embodiments, the stirring speed of the reaction solution is 300 r / min to 450 r / min.

[0107] For example, the stirring speed of the reaction solution is any value or a range between any two of 300 r / min, 330 r / min, 360 r / min, 380 r / min, 400 r / min, 410 r / min, 420 r / min, 430 r / min, 440 r / min and 450 r / min.

[0108] In some embodiments, the pH of coprecipitation reaction I-2 is 10.40 to 10.65.

[0109] For example, the pH of coprecipitation reaction I-2 is any value among 10.40, 10.45, 10.50, 10.55, 10.60, and 10.65, or a range between any two.

[0110] In some embodiments, the concentration of the complexing agent in coprecipitation reaction I-2 is 6.0-10.0 g / L.

[0111] For example, the concentration of the complexing agent in coprecipitation reaction I-1 is any value or a range between 6.0 g / L, 6.5 g / L, 7.0 g / L, 7.5 g / L, 8.0 g / L, 8.5 g / L, 9.0 g / L, 9.5 g / L and 10.0 g / L.

[0112] In some embodiments, the temperature of coprecipitation reaction I-2 is 50-65°C.

[0113] For example, the temperature of coprecipitation reaction I-2 is any value or a range between any two of 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.

[0114] In some embodiments, the stirring speed of coprecipitation reaction I-2 is 100 r / min to 400 r / min.

[0115] For example, the stirring speed of coprecipitation reaction I-2 is any value or a range between 100 r / min, 150 r / min, 200 r / min, 250 r / min, 300 r / min, 350 r / min and 400 r / min.

[0116] In some embodiments, the pH of coprecipitation reaction II is 10.8 to 11.5.

[0117] For example, the pH of coprecipitation reaction II is any value among 10.8, 10.9, 11.0, 11.1, 11.2, 11.3, 11.4 and 11.5 or a range between any two.

[0118] In some embodiments, the concentration of the complexing agent in coprecipitation reaction II is 11.0-12.0 g / L.

[0119] For example, the concentration of the complexing agent in coprecipitation reaction II is any value or a range between 11.0 g / L, 11.1 g / L, 11.2 g / L, 11.3 g / L, 11.4 g / L, 11.5 g / L, 11.6 g / L, 11.7 g / L, 11.8 g / L, 11.9 g / L, and 12.0 g / L.

[0120] In some embodiments, the temperature of coprecipitation reaction II is 55-65°C.

[0121] For example, the temperature of coprecipitation reaction II is any value or a range between 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C, and 65°C.

[0122] In some embodiments, the stirring speed for coprecipitation reaction II is 400 r / min to 450 r / min.

[0123] For example, the stirring speed of coprecipitation reaction II is any value or a range between 400 r / min, 410 r / min, 420 r / min, 430 r / min, 440 r / min and 450 r / min.

[0124] Thirdly, embodiments of this application provide a cathode material, which is prepared by sintering a cathode material precursor obtained by the preparation method of the cathode material precursor in the first aspect of this application or the cathode material precursor in the second aspect of this application with a lithium source.

[0125] In some embodiments, the sintering temperature is 700℃~900℃ and the sintering time is 8h~15h.

[0126] For example, the sintering temperature is any value or a range between any two of 700°C, 710°C, 720°C, 730°C, 740°C, 750°C, 760°C, 770°C, 780°C, 760°C, 800°C, 810°C, 820°C, 830°C, 840°C, 850°C, 860°C, 870°C, 880°C, 890°C, and 900°C.

[0127] 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.

[0128] Fourthly, embodiments of this application provide a lithium-ion battery comprising the positive electrode material described in the third aspect of this application.

[0129] 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.

[0130] 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.

[0131] Understandably, lithium-ion batteries also include negative electrode plates, separators, and electrolytes.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] Electrolytes can be liquid, gel, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0136] 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.

[0137] 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.

[0138] Fifthly, embodiments of this application provide an electrical device that includes the lithium-ion battery described in the fourth aspect of this application.

[0139] Example The following examples describe the disclosure of this invention in more detail. These examples are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of this disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are based on weight, and all reagents used in the examples are commercially available or synthesized by conventional methods and can be used directly without further processing. The instruments used in the examples are also commercially available.

[0140] Example 1 This embodiment provides a cathode material precursor with the chemical formula Ni. 0.945 Ti 0.055 (OH)2, the secondary particles of the material have a spherical structure and a particle size of 9.85 μm.

[0141] The method for preparing the cathode material precursor in this embodiment is specifically carried out through the following steps: Solution preparation: Prepare appropriate amounts of 120 g / L nickel sulfate solution and 120 g / L titanium oxysulfate solution. Mix the nickel sulfate solution, titanium oxysulfate solution, and pure water thoroughly. Prepare a metal salt solution according to the molar ratio Ni:Ti = 94.5:5.5, wherein the sum of the mass concentrations of nickel and titanium ions is 120 g / L.

[0142] Preparation of the base solution: Add pure water, sodium hydroxide solution (mass percentage concentration of 20.5%), and ammonia solution (mass percentage concentration of 10.5%) to the reaction vessel, and introduce nitrogen gas as a protective gas. The reaction temperature is 60℃, the reaction speed is 450 r / min, and the pH value is adjusted to 11.3 and the free ammonia concentration is 11.5 g / L to prepare the base solution conditions.

[0143] Coprecipitation Reaction I-1: Feed is pumped into the reactor at set flow rates. A metal salt solution (flow rate 1.50% / h of the reactor's usable volume), a sodium hydroxide solution (flow rate 0.40% / h of the reactor's usable volume), and ammonia (flow rate 0.10% / h of the reactor's usable volume) are introduced to initiate the coprecipitation reaction. Once the reaction slurry reaches the reactor's maximum volume, concentration begins. The stirring speed is gradually reduced from 450 r / min to 400 r / min, the pH value gradually decreases from 11.30 to 10.8, the free ammonia concentration is maintained at 11.5 g / L, and the solid content in the reactor gradually accumulates from 0 to 250 g / L. When the D50 reaches 3.0 μm, the overflow slurry is filtered and dried to obtain precursor seed crystals.

[0144] Preparation of reaction solution: Add pure water, sodium hydroxide solution (mass percentage concentration of 20.5%), and ammonia solution (mass percentage concentration of 10.5%) to the reaction vessel, and introduce nitrogen gas as a protective gas. The reaction temperature is 55℃, the reaction speed is 400 r / min, a certain amount of precursor crystals are added, and the reaction solution conditions are adjusted to pH value of 10.40 and free ammonia concentration of 5.0 g / L.

[0145] Coprecipitation reaction I-2: A metal salt solution (flow rate of 2% / h of the available reactor volume), a sodium hydroxide solution (flow rate of 0.4% / h of the available reactor volume), and ammonia (flow rate of 0.04% / h of the available reactor volume) are introduced into the reaction solution to carry out a coprecipitation reaction at a temperature of 55℃. When the reaction slurry reaches the upper limit of the reactor volume, concentration begins. During the reaction, the stirring speed is gradually reduced from 400 r / min to 100 r / min, the pH value is maintained at 10.4, and the free ammonia concentration gradually increases from 5.0 g / L to 6.0 g / L. The solid content in the reactor gradually accumulates from 0 to 300 g / L, and particles with a D50 value meeting the requirements are obtained.

[0146] Post-processing: The overflow positive electrode precursor material slurry is filtered and washed, and the filter cake is dried, sieved, and demagnetized to obtain the positive electrode material precursor.

[0147] Example 2 This embodiment provides a cathode material precursor with the chemical formula Ni. 0.94 Ti 0.06 (OH)2, the secondary particles of the material have a spherical structure and a particle size of 9.78 μm.

[0148] The cathode material precursor in this embodiment was prepared using a method similar to that in Example 1, except that: In the solution preparation step, the metal salt solution is prepared according to the molar ratio Ni:Ti = 94.0:6.0.

[0149] In step I-2 of the coprecipitation reaction, the concentration of free ammonia gradually increases from 5.0 g / L to 10.0 g / L.

[0150] Example 3 This embodiment provides a cathode material precursor with the chemical formula Ni. 0.90 Ti 0.10 (OH)2, the secondary particles of the material have a spherical structure and a particle size of 10.35 μm.

[0151] The cathode material precursor in this embodiment was prepared using a method similar to that in Example 1, except that: In the solution preparation step, the metal salt solution is prepared according to the molar ratio Ni:Ti = 90.0:10.0.

[0152] In step I-2 of the coprecipitation reaction, the pH value gradually increased from 10.4 to 10.65, and the free ammonia concentration gradually increased from 5.0 g / L to 8.0 g / L.

[0153] The precursor prepared in this embodiment was tested by XRD, and the full width at half maximum (FWHM) of the diffraction peaks corresponding to the (001) crystal plane was 0.290°, the FWHM of the diffraction peaks corresponding to the (100) crystal plane was 0.303°, and the FWHM of the diffraction peaks corresponding to the (101) crystal plane was 0.400°. The XRD was measured by an X-ray diffractometer, referring to the standard GA / T 2079-2023. The crystal structure was tested using a RigakuSmartLab 9kW X-ray diffractometer (XRD, Cu Kα), with a scanning range of 10-85° and a scanning rate of 4° / min.

[0154] Example 4 This embodiment provides a cathode material precursor with the chemical formula Ni. 0.85 Ti 0.15 (OH)2, the secondary particles of the material have a spherical structure and a particle size of 10.13 μm.

[0155] The cathode material precursor in this embodiment was prepared using a method similar to that in Example 1, except that: In the solution preparation step, the metal salt solution is prepared according to the molar ratio Ni:Ti = 85.0:15.0.

[0156] The rotation speed during the preparation of the reaction solution is 350 r / min.

[0157] In the coprecipitation reaction step I-2, the stirring speed was gradually reduced from 350 r / min to 100 r / min, the pH value was gradually increased from 10.4 to 10.65, and the free ammonia concentration was gradually increased from 5.0 g / L to 8.0 g / L.

[0158] Example 5 This embodiment provides a cathode material precursor with the chemical formula Ni. 0.80 Ti 0.20 (OH)2, the secondary particles of the material have a spherical structure and a particle size of 9.97 μm.

[0159] The cathode material precursor in this embodiment was prepared using a method similar to that in Example 1, except that: In the solution preparation step, the metal salt solution is prepared according to the molar ratio Ni:Ti = 80.0:20.0.

[0160] The rotation speed during the preparation of the reaction solution is 300 r / min.

[0161] In the coprecipitation reaction step I-2, the stirring speed of the reaction process was gradually reduced from 300 r / min to 100 r / min, the free ammonia concentration was gradually increased from 5.0 g / L to 10.0 g / L, and the solid content in the reactor gradually accumulated from 0 to 250 g / L.

[0162] Example 6 This embodiment provides a cathode material precursor with the chemical formula Ni. 0.90 Ti 0.10 (OH)2, the secondary particles of the material have a spherical structure and a particle size of 9.83 μm.

[0163] The cathode material precursor in this embodiment was prepared using a method similar to that in Example 1, except that: In the solution preparation step, the metal salt solution is prepared according to the molar ratio Ni:Ti = 90.0:10.0.

[0164] In the reaction solution preparation step, the reaction temperature is 65℃.

[0165] In the coprecipitation reaction step I-2, the reaction temperature was 65℃, the pH value gradually increased from 10.4 to 10.65, and the free ammonia concentration gradually increased from 5.0 g / L to 8.0 g / L.

[0166] Example 7 This embodiment provides a cathode material precursor with the chemical formula Ni. 0.90 Ti 0.10 (OH)2, the secondary particles of the material have a spherical structure and a particle size of 10.25 μm.

[0167] The cathode material precursor in this embodiment was prepared using a method similar to that in Example 1, except that: In the solution preparation step, the metal salt solution is prepared according to the molar ratio Ni:Ti = 90.0:10.0.

[0168] In step I-2 of the coprecipitation reaction, the pH was maintained at 10.65 and the free ammonia concentration was maintained at 8.0 g / L.

[0169] Example 8 This embodiment provides a cathode material precursor with the chemical formula Ni. 0.90 Ti 0.10 (OH)2, the secondary particles of the material have a spherical structure and a particle size of 3.42 μm.

[0170] The method for preparing the cathode material precursor in this embodiment is specifically carried out through the following steps: Solution preparation: Prepare appropriate amounts of 120 g / L nickel sulfate solution and 120 g / L titanium oxysulfate solution. Mix the nickel sulfate solution, titanium oxysulfate solution, and pure water thoroughly. Prepare a metal salt solution according to the molar ratio Ni:Ti = 90.0:10.0, wherein the sum of the mass concentrations of nickel and titanium ions is 120 g / L.

[0171] Preparation of the base solution: Add pure water, sodium hydroxide solution (mass percentage concentration of 20.5%), and ammonia solution (mass percentage concentration of 10.5%) to the reaction vessel, and introduce nitrogen gas as a protective gas. The reaction temperature is 60℃, the reaction speed is 450 r / min, and the pH value is adjusted to 11.3 and the free ammonia concentration is 11.5 g / L to prepare the base solution conditions.

[0172] Coprecipitation reaction I: A metal salt solution (flow rate of 1.50% / h of the available volume of the reactor), a sodium hydroxide solution (flow rate of 0.40% / h of the available volume of the reactor), and ammonia water (flow rate of 0.10% / h of the available volume of the reactor) are introduced into the bottom liquid to carry out a coprecipitation reaction. When the reaction slurry reaches the upper limit of the reactor volume, concentration begins. During the reaction, the stirring speed is gradually reduced from 450 r / min to 400 r / min, the pH value is gradually reduced from 11.30 to 10.8, the free ammonia concentration is maintained at 11.5 g / L, and the solid content in the reactor gradually accumulates from 0 to 250 g / L. The reaction yields particles with a D50 that meet the requirements.

[0173] Post-processing: The overflow positive electrode precursor material slurry is filtered and washed, and the filter cake is dried, sieved, and demagnetized to obtain Ni. 0.90 Ti 0.10 (OH)2.

[0174] Example 9 This embodiment provides a cathode material precursor with the chemical formula Ni. 0.89 Ti 0.10 Al 0.01 (OH)2, the secondary particles of the material have a spherical structure and a particle size of 10.35 μm.

[0175] The cathode material precursor in this embodiment was prepared using a method similar to that in Example 1, except that: In the solution preparation step, nickel sulfate solution, titanium oxysulfate solution, aluminum sulfate solution and pure water are mixed and stirred evenly to prepare a metal salt solution according to the molar ratio Ni:Ti:Al=89:10:1, wherein the sum of the mass concentrations of nickel, titanium and aluminum ions is 120g / L.

[0176] In step I-2 of the coprecipitation reaction, the feed is pumped into the reactor at the set flow rate. A metal salt solution (flow rate of 2% / h of the reactor's usable volume), a sodium hydroxide solution (flow rate of 0.4% / h of the reactor's usable volume), and ammonia water (flow rate of 0.04% / h of the reactor's usable volume) are introduced to carry out the coprecipitation reaction. When the reaction slurry reaches the upper limit of the reactor's volume, concentration begins. During the reaction, the stirring speed is gradually reduced from 400 r / min to 100 r / min, the pH value gradually increases from 10.4 to 10.65, and the free ammonia concentration gradually increases from 5.0 g / L to 8.0 g / L.

[0177] Comparative Example 1 This embodiment provides a cathode material precursor with the chemical formula Ni(OH)2. The secondary particles of the material have a spherical structure and a particle size of 10.13 μm.

[0178] The method for preparing the cathode material precursor in this embodiment is specifically carried out through the following steps: (1) Prepare an appropriate amount of nickel sulfate solution of 120 g / L.

[0179] (2) Add pure water, sodium hydroxide solution (mass percentage concentration of 20.5%), and ammonia solution (mass percentage concentration of 10.5%) to the reactor, and introduce nitrogen gas as a protective gas. The reaction temperature is 55℃, the reaction speed is 400 r / min, a certain amount of precursor seed crystals are added, and the pH value is adjusted to 10.40 and the free ammonia concentration is 5.0 g / L as the bottom liquid conditions. Feed is pumped into the reactor at the set flow rate. A metal salt solution (flow rate of 2% / h of the reactor's usable volume), a sodium hydroxide solution (flow rate of 0.4% / h of the reactor's usable volume), and ammonia (flow rate of 0.04% / h of the reactor's usable volume) are introduced to initiate a co-precipitation reaction. Once the reaction slurry reaches the reactor's maximum volume, concentration begins. During the reaction, the stirring speed is gradually reduced from 400 rpm to 100 rpm, the pH value gradually increases from 10.4 to 10.65, and the free ammonia concentration gradually increases from 5.0 g / L to 8.0 g / L. The solid content in the reactor gradually accumulates from 0 to 300 g / L.

[0180] (3) The reaction yields particles with D50 that meet the requirements. The overflow positive electrode precursor material slurry is filtered and washed. The filter cake is dried, sieved, and demagnetized to obtain Ni(OH)2.

[0181] Comparative Example 2 This embodiment provides a cathode material precursor with the chemical formula Ni. 0.97 Ti 0.03 (OH)2, the secondary particles of the material have a spherical structure and a particle size of 9.91 μm.

[0182] The cathode material precursor in this embodiment was prepared using a method similar to that in Example 1, except that: In the solution preparation step, the metal salt solution is prepared according to the molar ratio Ni:Ti = 97.0:3.0.

[0183] In step I-2 of the coprecipitation reaction, the pH was maintained at 10.2 and the free ammonia concentration was maintained at 4.0 g / L.

[0184] Comparative Example 3 This embodiment provides a cathode material precursor with the chemical formula Ni. 0.77 Co 0.1 Mn 0.1 Ti 0.03 (OH)2, the secondary particles of the material have a spherical structure and a particle size of 2.65 μm.

[0185] (1) Prepare appropriate amounts of 120 g / L nickel sulfate solution and 120 g / L titanium oxysulfate solution. Mix the nickel sulfate solution, titanium oxysulfate solution and pure water and stir well. Prepare a metal salt solution according to the molar ratio Ni:Co:Mn:Ti=77.0:10.0:10.0:3.0, wherein the sum of the mass concentrations of nickel, cobalt, manganese and titanium ions is 120 g / L.

[0186] (2) Add pure water, sodium hydroxide solution (mass percentage concentration of 20.5%), and ammonia solution (mass percentage concentration of 10.5%) to the reactor, and introduce nitrogen gas as a protective gas. The reaction temperature is 60℃, the reaction speed is 450 r / min, and the bottom liquid conditions are adjusted to pH 11.3 and free ammonia concentration of 11.5 g / L. Feed is pumped into the reactor at the set flow rate. Metal salt solution (flow rate of 1.50% / h of the reactor's usable volume), sodium hydroxide solution (flow rate of 0.40% / h of the reactor's usable volume), and ammonia water (flow rate of 0.10% / h of the reactor's usable volume) are introduced to carry out a co-precipitation reaction. When the reaction slurry reaches the upper limit of the reactor's volume, concentration begins. During the reaction process, the stirring speed is gradually reduced from 450 r / min to 400 r / min, the pH value is gradually reduced from 11.30 to 10.8, the free ammonia concentration is maintained at 11.5 g / L, and the solid content in the reactor gradually accumulates from 0 to 250 g / L.

[0187] (3) After the reaction yields particles with D50 meeting the requirements, the overflow positive electrode precursor material slurry is filtered and washed. The filter cake is dried, sieved, and demagnetized to obtain Ni. 0.77 Co 0.1 Mn 0.1 Ti 0.03 (OH)2.

[0188] Test case The physicochemical data and electrochemical performance of the cathode material precursors prepared in the examples and the cathode material precursors prepared in the comparative examples, as well as the batteries, were tested.

[0189] The particle size D50 of the secondary particles was determined by a laser particle size analyzer (instrument model: Mastersizer3000) in accordance with the national standard GB / T 19077-2016 Particle size analysis by laser diffraction. 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. Specific surface area test method: The specific surface area was determined by a fully automated nitrogen adsorption specific surface area analyzer (instrument model: BELPREP-VACII / BELSORP-MINI-X) in accordance with the national standard GB / T 19587-2017 "Determination of specific surface area of ​​solid substances by gas adsorption BET method".

[0190] Porosity Testing Method: Specific testing method for the porosity of secondary particles: Adjust the scanning electron microscope (SEM) to a suitable magnification and take a cross-sectional SEM image of the secondary particles of the cathode material precursor. Then, analyze the cross-sectional SEM image using image analysis software and calculate the porosity. The calculation formula is: Total porosity = [(Sum of pore areas of secondary particles in the cross-section / Cross-sectional area of ​​secondary particles) × 100] (%); For example, the magnification of the cross-sectional SEM image can be 7.0K, 9.0K, 10.0K, etc., and the specific magnification should be such that there is only one complete or nearly complete single secondary particle sphere cross-section in the SEM field of view.

[0191] The physicochemical data of the cathode material precursors in the examples and comparative examples are shown in Table 1.

[0192] Table 1 Physicochemical properties of precursors prepared in the examples and comparative examples Preparation of cathode materials for lithium-ion batteries: The cathode material precursors prepared in the aforementioned examples and comparative examples were mixed with LiOH in a molar ratio of 1:1.03 (total molar amount of metal elements in the cathode material precursor: molar amount of Li element) using a high-speed mixer to obtain a mixture. The mixture is sintered in a box furnace under air atmosphere (sintering temperature 710℃, sintering time 12h). The sintered material is then cooled, crushed and sieved in sequence to obtain lithium-ion battery cathode material.

[0193] Preparation of lithium-ion batteries: (1) Prepare a slurry by mixing the above-mentioned lithium-ion battery cathode material, conductive carbon black, and binder PVDF (polyvinylidene fluoride) in a ratio of 8:1:1, and uniformly coat it on an aluminum foil with a length and width of 2 cm × 1 cm to make a positive electrode sheet. (2) Assemble a button battery in a vacuum glove box with a battery case, positive electrode sheet, negative electrode sheet (lithium metal sheet), separator, spring piece, gasket, and electrolyte (1 mol / L LiPF6 / EC:DMC (volume ratio 1:1)).

[0194] Use a BlueTEC test system to test the electrochemical performance of the prepared lithium-ion battery. The voltage range for testing is 2.0~4.3V, and the current density 1C = 200 mAh / g.

[0195] The test results of the button batteries prepared in the examples and comparative examples are shown in Table 2.

[0196] Table 2 Performance indicators of the cathode materials prepared in the examples and comparative examples Combining FIGS. 1 to 4 and Tables 1 to 2, it can be seen that the cathode material precursor of the present application uses Ti as the basic element, and its molar ratio is controlled within the range of 0.05 < y ≤ 0.2. Through the interaction between Ti and the crystal lattice, it is possible to effectively expand the interlayer spacing of the subsequently prepared cathode material, and then release more interlayer active sites. This characteristic is different from the lithium nickelate or doped lithium nickelate system, which generally has problems such as a narrow interlayer spacing, a small number of interlayer active sites, and failure to be effectively activated in the case of low doping. The reasonable introduction of the Ti element in the present application not only effectively compensates for the capacity loss that may be caused by the Ti element occupying part of the nickel site, but also significantly optimizes its rate performance while improving the specific capacity of the cathode material.

[0197] As described above, the above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A cathode material precursor, characterized in that, The chemical formula of the precursor of the positive electrode material is Ni x Ti y Me z (OH)2; wherein, 0.8 ≤ x < 0.95, 0.05 < y ≤ 0.2, 0 ≤ z ≤ 0.01; Me includes one or more of Mn, Co, Al, W, Zr, Si, Mg, B, Sr, Ti, Nb, and Ta.

2. The cathode material precursor according to claim 1, characterized in that, The cathode material precursor satisfies at least one of the following conditions: (1) The precursor comprises spherical secondary particles, and the secondary particles comprise a plurality of primary particles; (2) The D50 of the precursor is 2.0 μm to 15.0 μm; (3) The particle size distribution of the precursor ranges from 0.5 to 1.

2. (4) The specific surface area of ​​the precursor is 20m². 2 / g~60m 2 / g; (5) The tap density of the precursor is 1.3 g / cm³. 3 ~2.3g / cm 3 ; (6) The cross-sectional porosity of the precursor is ≤15%; optionally, the cross-sectional porosity is ≤10%, and more preferably, the cross-sectional porosity is ≤8%; (7) The Ni x Ti y Me z In (OH)2, 0.1≤y≤0.

2.

3. The cathode material precursor according to claim 1 or 2, characterized in that, The X-ray powder diffraction pattern of the cathode material precursor satisfies: The full width at half maximum (FWHM) of the diffraction peak corresponding to the (001) crystal plane is 0.2~0.9°; optionally, the FWHM of the diffraction peak corresponding to the (001) crystal plane is 0.2~0.5°. And / or, the full width at half maximum (FWHM) of the diffraction peak corresponding to the (100) crystal plane is 0.2~0.6°; optionally, the full width at half maximum (FWHM) of the diffraction peak corresponding to the (100) crystal plane is 0.2~0.4°. And / or, the full width at half maximum (FWHM) of the diffraction peak corresponding to the (101) crystal plane is 0.3~0.9°; optionally, the full width at half maximum (FWHM) of the diffraction peak corresponding to the (101) crystal plane is 0.3~0.6°. Among them, the diffraction peak corresponding to the (001) crystal plane is at a diffraction angle of 2. The diffraction peaks are located at 17°-21°; the diffraction peaks corresponding to the (100) crystal plane are at diffraction angles of 2° and 3°. The diffraction peaks at 32°-35°; the diffraction peaks corresponding to the (101) crystal plane are at diffraction angles 2° and 35°. The diffraction peak is located at 37°-41°.

4. A method for preparing a cathode material precursor as described in any one of claims 1 to 3, characterized in that, Includes the following steps: Prepare metal salt solutions, precipitant solutions, and complexing agent solutions separately; The solvent, the precipitant solution, and the complexing agent solution are mixed to obtain the base liquid; After simultaneously introducing the metal salt solution, the precipitant solution, and the complexing agent solution into the base liquid to carry out a co-precipitation reaction, a precursor slurry is obtained. The precursor slurry is post-processed to obtain the cathode material precursor.

5. The method for preparing the cathode material precursor according to claim 4, characterized in that, The preparation method satisfies at least one of the following conditions: a. The coprecipitation reaction process includes: simultaneously introducing the metal salt solution, the precipitant solution, and the complexing agent solution into the base liquid to carry out coprecipitation reaction I-1 to obtain seed crystals; mixing the seed crystals, the precipitant solution, and the complexing agent solution to obtain a reaction solution; and continuing to introduce the metal salt solution, the precipitant solution, and the complexing agent solution into the reaction solution to carry out coprecipitation reaction I-2 to obtain a precursor slurry; b. The coprecipitation reaction process includes: simultaneously introducing the metal salt solution, the precipitant solution and the complexing agent solution into the bottom liquid to carry out coprecipitation reaction II until the reaction slurry reaches the upper limit of the reactor volume, and then concentrating to obtain the precursor slurry. In the process of concentration, the stirring speed is less than the stirring speed of coprecipitation reaction II, and the pH value of concentration is less than the pH value of coprecipitation reaction II. c. The post-processing includes: sequentially performing solid-liquid separation, washing, drying and sieving on the precursor slurry to obtain the cathode material precursor; d. The raw materials for the metal salt solution include nickel salt and titanium salt; optionally, the raw materials for the metal salt solution also include Me salt, wherein Me is selected from at least one of Mn, Co, Al, W, Zr, Si, Mg, B, Sr, Ti, Nb and Ta; e. The precipitant includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, or potassium carbonate; f. The complexing agent includes at least one of ammonia, ammonium bicarbonate, ammonium carbonate, citric acid, sodium citrate, ammonium citrate, oxalic acid, or ammonium oxalate; g. The total mass concentration of metal ions in the metal salt solution is 110~130 g / L; h. The mass fraction of the solute in the precipitant solution is 18~22 wt%; i. The solute mass fraction of the complexing agent solution is 9~12 wt%.

6. The method for preparing the cathode material precursor according to claim 4 or 5, characterized in that, The preparation method satisfies at least one of the following conditions: A. The conditions of the base solution include: the pH of the base solution is 11.0-11.6, and / or the concentration of the complexing agent in the base solution is 9-13 g / L, and / or the temperature of the base solution is 55-65℃, and / or the stirring speed of the base solution is 400-500 r / min; B. The conditions for the coprecipitation reaction I-1 include: the pH of the coprecipitation reaction I-1 is 10.8~11.5, and / or the concentration of the complexing agent in the coprecipitation reaction I-1 is 11.0-12.0 g / L, and / or the temperature of the coprecipitation reaction I-1 is 55-65℃, and / or the stirring speed of the coprecipitation reaction I-1 is 400 r / min~450 r / min; C. The conditions of the reaction solution include: the pH of the reaction solution is 10.25-10.45, and / or the concentration of the complexing agent in the reaction solution is 4.5-5.5 g / L, and / or the temperature of the reaction solution is 50-65℃, and / or the stirring speed of the reaction solution is 300-450 r / min; D. The conditions for the coprecipitation reaction I-2 include: the pH of the coprecipitation reaction I-2 is 10.40~10.65; and / or the concentration of the complexing agent in the coprecipitation reaction I-2 is 6~10 g / L; and / or the temperature of the coprecipitation reaction I-2 is 50-65℃; and / or the stirring speed of the coprecipitation reaction I-2 is 100 r / min~400 r / min; E. The conditions for the coprecipitation reaction II include: the pH of the coprecipitation reaction II is 10.8-11.5; and / or the concentration of the complexing agent in the coprecipitation reaction II is 11.0-12.0 g / L; and / or the temperature of the coprecipitation reaction II is 55-65℃; and / or the stirring speed of the coprecipitation reaction II is 400 r / min-450 r / min.

7. A positive electrode material, characterized in that, The cathode material precursor prepared by any one of claims 1-3 or by any one of claims 4-6 is obtained by sintering with a lithium source.

8. A lithium-ion battery, characterized in that, It includes the cathode material as described in claim 7.

9. An electrical-related device, characterized in that, It includes the lithium-ion battery as described in claim 8.

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