High-nickel hydroxide, preparation method thereof, positive electrode material, lithium ion battery and electrical equipment

Abstract

The application provides a high-nickel hydroxide, a preparation method of the high-nickel hydroxide, a positive electrode material, a lithium ion battery and an electrical equipment, and relates to the field of lithium ion batteries. x Co y Mn z W a1 Mo a2 Nb a3 M b (OH) 2+σ wherein 0.8<=x<1, 0<=y<0.2, 0<=z<0.2, 0.0005<=a1<=0.05, 0.0005<=a2<=0.05, 0.0005<=a3<=0.05, 0<=b<=0.05, x+y+z+a1+a2+a3+b=1, 0<=sigma<0.6, and M comprises at least one of Zr, Ti and Sb; the variation coefficients of the concentration distributions of W, Mo and Nb in the secondary particles of the high-nickel hydroxide are all less than 20%. The positive electrode material prepared from the high-nickel hydroxide has a slower capacity attenuation and a higher cycle retention rate in a long cycle process.

Description

Technical Field

[0001] This application relates to the field of lithium-ion batteries, and more particularly to a high-nickel hydroxide and its preparation method, a cathode material, a lithium-ion battery, and electrical equipment. Background Technology

[0002] With the continuous increase in demand for high-energy-density lithium-ion batteries from the new energy vehicle and energy storage industries, high-nickel ternary cathode materials (NCM / NCA, Ni≥0.8) have become the mainstream technology due to their ultra-high specific capacity (190-220 mAh / g). The structure and performance of their core precursors directly determine the overall quality of the battery. However, the inherent defects brought about by high nickel content have become a key bottleneck for industrialization: First, high nickel has extremely high surface activity, continuously undergoing side reactions with the electrolyte to generate an unstable cathode electrolyte interphase (CEI) film, consuming active lithium and increasing interfacial impedance, thus deteriorating rate performance; Second, Ni... 3+ Easily reduced to Ni 2+ It releases lattice oxygen, which can easily trigger thermal runaway at high temperatures or when overcharged, posing a significant safety hazard.

[0003] While existing technologies can improve performance in certain areas, they cannot simultaneously resolve the multiple contradictions between structural stability, interface protection, thermal safety, and ion conduction, and are prone to problems such as doping segregation and limited gain.

[0004] Therefore, there is an urgent need to develop a ternary cathode material precursor that combines high cycle stability and high capacity to promote the practical application of high-nickel cathode materials in lithium-ion batteries. Summary of the Invention

[0005] The purpose of this application is to provide a high-nickel hydroxide and its preparation method, a cathode material, a lithium-ion battery, and electrical equipment to solve the above-mentioned problems.

[0006] To achieve the above objectives, this application adopts the following technical solution: A high-nickel hydroxide, wherein the chemical formula of the high-nickel hydroxide is Ni x Co y Mn z W a1 Mo a2 Nb a3 M b (OH) 2+σ Wherein, 0.8≤x<1, 0≤y<0.2, 0≤z<0.2, 0.0005≤a1≤0.05, 0.0005≤a2≤0.05, 0.0005≤a3≤0.05, 0≤b≤0.05, x+y+z+a1+a2+a3+b=1, 0≤σ<0.6, and M includes at least one of Zr, Ti, and Sb; The high-nickel hydroxide includes secondary particles formed from primary particles; the coefficients of variation of the concentration distribution of W, Mo, and Nb in the secondary particles are all <20%. Optionally, the coefficients of variation of the concentration distribution of W, Mo, and Nb in the secondary particles are all <15%.

[0007] The method for obtaining the coefficient of variation (CV) includes: polishing the cross-section of the secondary particles of the high-nickel hydroxide precursor, and then using a scanning electron microscope-energy dispersive spectroscopy (SEM-EDS) to perform line scanning or area scanning to collect intensity values; then, within the cross-section of the secondary particles, selecting N sampling points (N≥100) located within a region from the geometric center to 0.8 times the radius of the secondary particles (0.8r) to collect the intensity values ​​of the target metal element; and then calculating the standard deviation σ and arithmetic mean of the intensity values ​​for each target metal element. The ratio of the intensity values ​​collected by EDS is defined as the coefficient of variation (CV) of the target metal element. The intensity values ​​collected by EDS can be used as quantitative parameters characterizing the concentration distribution of the target metal element within the secondary particles. The coefficient of variation calculated based on the intensity values ​​can effectively reflect the uniformity of the target metal element distribution.

[0008] Specifically, the formula for calculating the coefficient of variation is as follows: ; Where: CV—the coefficient of variation of the intensity value corresponding to the concentration distribution of a certain target metal element; σ—the standard deviation of the intensity values ​​of a target metallic element acquired by EDS scanning; —The average intensity value of a certain target metal element acquired by EDS scanning; N—The total number of intensity values ​​of a certain target metal element acquired by EDS scanning; i—the index of the intensity value of a certain target metal element acquired by EDS scanning, i = 1, 2...... N; xi — the i-th intensity value of a target metallic element acquired by EDS scanning.

[0009] In some embodiments, the coefficient of variation of the Ni concentration distribution in the secondary particles is <10%; alternatively, the coefficient of variation of the Ni concentration distribution in the secondary particles is less than 5%. And / or, the coefficient of variation of the Co concentration distribution in the secondary particles is <20%; optionally, the coefficient of variation of the Co concentration distribution in the secondary particles is <10%. And / or, the coefficient of variation of the Mn concentration distribution in the secondary particles is <20%; optionally, the coefficient of variation of the Mn concentration distribution in the secondary particles is <10%. And / or, when b > 0, the coefficient of variation of the concentration distribution of each dopant element other than Ni, Co, and Mn in the secondary particles is < 20%. Optionally, the coefficient of variation of the concentration distribution of each dopant element other than Ni, Co, and Mn in the secondary particles is < 15%.

[0010] In some embodiments, the ratio of the maximum to the minimum subscript value of the dopant element in the chemical formula of the high-nickel hydroxide is greater than or equal to 1 and less than or equal to 2; And / or, the particle size D50 of the high-nickel hydroxide is 10.0 μm to 15.0 μm; And / or, the BET of the high-nickel hydroxide is 5 m 2 / g-30 m 2 / g; And / or, the tap density TD of the high-nickel hydroxide is 1.8 g / cm³. 3 -2.1g / cm 3 .

[0011] This application also provides a method for preparing the high-nickel hydroxide as described above, comprising: Preparation of seed crystals: A metal salt suspension, a precipitant solution, and a complexing agent solution are introduced into a first base solution containing a precipitant and a complexing agent to carry out a first coprecipitation reaction until the particle size of precipitate 1 reaches the first particle size. After collecting precipitate 1 and performing post-processing, seed crystals are obtained. Seed crystal growth: The seed crystal is added to the second base solution containing the precipitant and the complexing agent, and then the metal salt suspension, the precipitant solution and the complexing agent solution are added to carry out the second coprecipitation reaction until the particle size of precipitate 2 reaches the second particle size. The precipitate 2 is collected and post-processed to obtain the high nickel hydroxide. The metal salt suspension comprises nickel salt, cobalt salt, manganese salt, and doped compounds, wherein the doped compounds include tungstate, Mo oxide, and organic Nb salt; in the metal salt suspension, W accounts for 0.0005-0.05% of the total metal molar amount; in the metal salt suspension, Mo accounts for 0.0005-0.05% of the total metal molar amount; in the metal salt suspension, Nb accounts for 0.0005-0.05% of the total metal molar amount.

[0012] Nickel salts, cobalt salts, and manganese salts are chloride salts or sulfate salts.

[0013] In some embodiments, the doping compound further includes an M source, the M source comprising at least one of a Zr salt, an oxoacid salt of Ti, and an organic Sb salt; in the metal salt suspension, Zr accounts for 0-0.05 of the total metal molar amount; in the metal salt suspension, Ti accounts for 0-0.05 of the total metal molar amount; in the metal salt suspension, Sb accounts for 0-0.05 of the total metal molar amount.

[0014] The aforementioned metal salt suspension is an aqueous suspension containing dissolved metal salts and slightly soluble or sparingly soluble metal compounds.

[0015] In some embodiments, the precipitant includes sodium hydroxide; The complexing agent includes ammonia; And / or, the pH value of the first substrate solution is 11.0-11.4; And / or, the ammonia concentration of the first base solution is 3.0 g / L-5.0 g / L; And / or, when the first coprecipitation reaction is carried out, the pH value of the reaction system is 9.0-10.8; And / or, when the first coprecipitation reaction is carried out, the ammonia concentration in the reaction system is 1.0 g / L-6.0 g / L; And / or, in the seed crystal preparation step, the flow rate of the metal salt suspension added to the first base liquid is 7% / h-9% / h of the reaction vessel volume; And / or, the temperature of the first coprecipitation reaction is 50℃-64℃; And / or, the stirring speed of the first coprecipitation reaction is 600 r / min-1200 r / min; In some embodiments, the first particle size is 4μm-6μm.

[0016] In some embodiments, the pH value of the second substrate is 9.0-10.5; And / or, the ammonia concentration of the second substrate is 1.0 g / L-5.5 g / L; And / or, when carrying out the second coprecipitation reaction, the pH of the reaction system is 9.0-10.8; And / or, when carrying out the second coprecipitation reaction, the ammonia concentration in the reaction system is 1.0 g / L-6.0 g / L; And / or, in the seed crystal growth step, the flow rate of the metal salt suspension added to the second base liquid is 7% / h-9% / h of the reaction vessel volume; And / or, the temperature of the second coprecipitation reaction is 65℃-75℃; And / or, the stirring speed for the second coprecipitation reaction is 200 r / min-500 r / min; And / or, the second particle size is 10 μm-15 μm; And / or, both the first coprecipitation reaction and the second coprecipitation reaction are carried out under inert gas protection.

[0017] This application also provides a cathode material, which is prepared by sintering a mixture of high-nickel hydroxide and a lithium source; The high-nickel hydroxide is either the high-nickel hydroxide described above or a high-nickel hydroxide prepared by the preparation method described above.

[0018] This application also provides a lithium-ion battery, including the positive electrode material described above.

[0019] This application also provides an electrical device, including the lithium-ion battery described above.

[0020] Compared with the prior art, the beneficial effects of this application include: This application introduces multiple doping elements, including W, Mo, and Nb, into high-nickel hydroxides, achieving a uniform distribution of doping elements (low coefficient of variation). The selected doping elements are all in high oxidation states (W...). 6+ 、Nb 5+ Mo 4+ Its ionic radius (0.60–0.64 Å) is similar to that of the main transition metal ions (Ni) in high-nickel layered oxides. 2+ With a ion size close to 0.69 Å, stable solid solutions can be formed through substitutional doping, avoiding severe lattice distortion caused by ion size mismatch. Simultaneously, in the initial stages of charge and discharge, high-valence elements preferentially provide charge compensation, reducing the need for further oxidation of active ions and thus stabilizing lattice oxygen. During charge and discharge, the uniform expansion and contraction of the lattice with uniform element distribution results in more consistent stress distribution and less susceptibility to cracking. This effectively suppresses particle cracking, structural phase transitions, interfacial side reactions, and transition metal dissolution, resulting in slower capacity decay and higher cycle retention in cathode materials prepared from high-nickel hydroxides during long-term cycling. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0022] Figure 1 Here is a surface SEM image of the high-nickel hydroxide from Example 1; Figure 2 The images show secondary particle cross-sectional SEM images and corresponding elemental distribution maps of the high-nickel hydroxide sample from Example 1; wherein, Figure 2 Image 2(a) is a secondary particle cross-section SEM image of the high-nickel hydroxide sample from Example 1; Figure 2 2(b) is the tungsten (W) element distribution diagram of the high-nickel hydroxide sample in Example 1; Figure 22(c) is the molybdenum (Mo) elemental distribution diagram of the high-nickel hydroxide sample in Example 1; Figure 2 2(d) in the figure is the niobium (Nb) element distribution diagram of the high nickel hydroxide sample in Example 1; Figure 3 Here are SEM images of the secondary particle cross-section and a schematic diagram of the line scan area of ​​the high-nickel hydroxide sample from Example 6; Figure 4 This is the element distribution diagram corresponding to Example 6; where, Figure 4 4(a) is the nickel (Ni) elemental distribution diagram of the high-nickel hydroxide sample in Example 6; Figure 4 4(b) is the tungsten (W) element distribution diagram of the high-nickel hydroxide sample in Example 6; Figure 4 4(c) is the niobium (Nb) element distribution diagram of the high-nickel hydroxide sample in Example 6; Figure 4 4(d) is the cobalt (Co) element distribution diagram of the high-nickel hydroxide sample in Example 6; Figure 4 4(e) in the figure is the molybdenum (Mo) elemental distribution diagram of the high-nickel hydroxide sample in Example 6; Figure 4 4(f) is the manganese (Mn) elemental distribution diagram of the high-nickel hydroxide sample in Example 6; Figure 4 4(g) is the zirconium (Zr) elemental distribution diagram of the high-nickel hydroxide sample in Example 6; Figure 4 4(h) in the figure is the titanium (Ti) element distribution diagram of the high nickel hydroxide sample in Example 6; Figure 4 4(i) is the antimony (Sb) elemental distribution diagram of the high-nickel hydroxide sample in Example 6. Detailed Implementation

[0023] As used in this article: "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0024] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0025] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0026] A high-nickel hydroxide, wherein the chemical formula of the high-nickel hydroxide is Ni x Co y Mn z W a1 Mo a2 Nb a3 M b (OH) 2+σ Wherein, 0.8≤x<1, 0≤y<0.2, 0≤z<0.2, 0.0005≤a1≤0.05, 0.0005≤a2≤0.05, 0.0005≤a3≤0.05, 0≤b≤0.05, x+y+z+a1+a2+a3+b=1, 0≤σ<0.6, and M includes at least one of Zr, Ti, and Sb; The high-nickel hydroxide includes secondary particles formed from primary particles; the coefficients of variation of the concentration distribution of W, Mo, and Nb in the secondary particles are all <20%. Optionally, the coefficients of variation of the concentration distribution of W, Mo, and Nb in the secondary particles are all <15%.

[0027] For example, in the chemical formula of high-nickel hydroxide, x can be any value between 0.8, 0.82, 0.85, 0.87, 0.9, 0.92, 0.95, 0.97, 0.98, 0.99, or 0.8 ≤ x < 1; y can be any value between 0, 0.02, 0.05, 0.07, 0.1, 0.12, 0.15, 0.17, 0.19, or 0 ≤ y < 0.2; z can be 0, 0.02, ... a1 can be any value between 0.0005, 0.001, 0.005, 0.015, 0.02, 0.025, 0.03, 0.035, 0.04, 0.045, 0.05, or 0.0005≤a1≤0.05; a2 can be 0. 0.0005, 0.001, 0.005, 0.01, 0.015, 0.02, 0.025, 0.03, 0.035, 0.04, 0.045, 0.05, or any value between 0.0005 ≤ a2 ≤ 0.05; a3 can be any value between 0.0005, 0.001, 0.005, 0.01, 0.015, 0.02, 0.025, 0.03, 0.035, 0.04, 0.05, or 0.0005 ≤ a2 ≤ 0.05; σ can be any value between 0.045, 0.05, or 0.0005≤a3≤0.05; b can be any value between 0, 0.005, 0.01, 0.015, 0.02, 0.025, 0.03, 0.035, 0.04, 0.045, 0.05, or 0≤b≤0.05; σ can be any value between 0.1, 0.2, 0.3, 0.4, 0.5, 0.59, or 0≤σ<0.6.

[0028] For example, in the secondary particles, the coefficients of variation of the concentration distribution of W, Mo, and Nb can be any value between <20%, <19%, <18%, <17%, <16%, <15%, <14%, <13%, <12%, <11%, <10%, <9%, <8%, <7%, <6%, <5%, or <20%; or the coefficient of variation of the concentration distribution of any one or two of the metal elements W, Mo, and Nb is <10%, and the coefficient of variation of the concentration distribution of the other one or two metal elements is <20%.

[0029] The coefficient of variation of element concentration distribution is used to characterize the relative dispersion of element distribution.

[0030] This application introduces multiple doping elements, including W, Mo, and Nb, into high-nickel hydroxides, achieving a uniform distribution of doping elements (low coefficient of variation). The selected doping elements are all in high oxidation states (W...). 6+ 、Nb 5+ Mo 4+Its ionic radius (0.60–0.64 Å) is similar to that of the main transition metal ions (Ni) in high-nickel layered oxides. 2+ With a ion size close to 0.69 Å, stable solid solutions can be formed through substitutional doping, avoiding severe lattice distortion caused by ion size mismatch. Simultaneously, in the initial stages of charge and discharge, high-valence elements preferentially provide charge compensation, reducing the need for further oxidation of active ions and thus stabilizing lattice oxygen. During charge and discharge, the uniform expansion and contraction of the lattice with uniform element distribution results in more consistent stress distribution and less susceptibility to cracking. This effectively suppresses particle cracking, structural phase transitions, interfacial side reactions, and transition metal dissolution, resulting in slower capacity decay and higher cycle retention in cathode materials prepared from high-nickel hydroxides during long-term cycling.

[0031] In some embodiments, the coefficient of variation of the Ni concentration distribution in the secondary particles is <10%; for example, the coefficient of variation of the Ni concentration distribution in the secondary particles can be <1%, <2%, <3%, <4%, <5%, <6%, <7%, <8%, <9%, or any value within the range of <10%.

[0032] In some embodiments, the coefficient of variation of the Co concentration distribution in the secondary particles is <20%; for example, the coefficient of variation of the Co concentration distribution in the secondary particles is <1%, <2%, <3%, <4%, <5%, <6%, <7%, <8%, <9%, <10%, <11%, <12%, <13%, <14%, <15%, <16%, <17%, <18%, <19%, or any value within the range of <20%.

[0033] In some embodiments, the coefficient of variation of the Mn concentration distribution in the secondary particles can be <20%; for example, the coefficient of variation of the Mn concentration distribution in the secondary particles can be <1%, <2%, <3%, <4%, <5%, <6%, <7%, <8%, <9%, <10%, <11%, <12%, <13%, <14%, <15%, <16%, <17%, <18%, <19%, or any value within the range of <20%.

[0034] High-nickel hydroxides can be used as precursors for cathode materials. The structural characteristics of the cathode material precursors directly affect the structure and performance of the cathode materials. When the coefficients of variation of Ni concentration distribution, Co concentration distribution, and Mn concentration distribution in high-nickel hydroxides meet the above conditions, Ni, Co, and Mn in the high-nickel hydroxides are uniformly distributed inside the material. This can reduce the problem of local stress concentration inside the particles, inhibit the generation of cracks, and is beneficial to the improvement of electrochemical performance.

[0035] In some embodiments, when b > 0, the coefficient of variation of the concentration distribution of each dopant element other than Ni, Co, and Mn in the secondary particles is < 20%. For example, the coefficient of variation of the concentration distribution of each dopant element other than Ni, Co, and Mn in the secondary particles can be < 20%, < 19%, < 18%, < 17%, < 16%, < 15%, < 14%, < 13%, < 12%, < 11%, < 10%, < 9%, < 8%, < 7%, < 6%, < 5%, or any value within the range of < 20%; or the coefficient of variation of the concentration distribution of any one or more metal elements other than Ni, Co, and Mn is < 10%, and the coefficient of variation of the concentration distribution of the other one or more metal elements is < 20%.

[0036] The dopant elements are uniformly distributed within the high-nickel hydroxide. These high-valence dopant elements have higher MO bond energies, which can effectively suppress layered phase transitions, reduce lithium-nickel mixing, and alleviate lattice stress during cycling. Co-doping with multiple elements such as W, Mo, Nb, and M can further suppress secondary particle cracking, the dissolution of transition metals in primary particles, and side reactions with the electrolyte. Therefore, specific dopant types and ranges can further maintain structural stability and higher long-cycle retention. However, these dopant elements are electrochemically inert and do not contribute to capacity. Their introduction dilutes the content of active Ni and Co, reducing the number of active sites that can participate in redox reactions, leading to a decrease in reversible specific capacity. Through extensive exploratory experiments, the inventors discovered that controlling the stoichiometry of each dopant element within the Ni... x Co y Mn z W a1 Mo a2 Nb a3 M b (OH) 2+σ When the chemical formula range of (0.8≤x<1, 0≤y<0.2, 0≤z<0.2, 0.0005≤a1≤0.05, 0.0005≤a2≤0.05, 0.0005≤a3≤0.05, 0≤b≤0.05, x+y+z+a1+a2+a3+b=1, 0≤σ<0.6, M includes at least one of Zr, Ti, and Sb) is within the range, it is possible to effectively improve the cycling performance of the material while having a high capacity.

[0037] In some embodiments, the doping elements include at least one of W, Mo, Nb, and Zr, Ti, and Sb. Introducing W, Mo, and Nb, and co-doping / composite doping with at least one of Zr, Ti, and Sb during the synthesis stage of lithium-ion battery cathode material precursors, can suppress lattice distortion and cation mixing, improve the cycle life of high-nickel materials under high voltage, and enhance thermal stability and safety.

[0038] In some embodiments, the ratio of the maximum to the minimum subscript value of the dopant element in the chemical formula of the high-nickel hydroxide is greater than or equal to 1 and less than or equal to 2. By controlling the concentration difference of the dopant element in the material, the doping uniformity of the dopant element in the material can be further improved, thereby further improving the battery cycle performance.

[0039] For example, the ratio of the maximum to the minimum subscript value of the dopant element in the chemical formula of high-nickel hydroxide can be 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 1.95, 2.0, or any value within the range of greater than or equal to 1 and less than or equal to 2.

[0040] The particle size D50 of the high-nickel hydroxide is 10.0 μm to 15.0 μm. For example, the particle size D50 of the high-nickel hydroxide is 10.0 μm, 10.5 μm, 11.0 μm, 11.5 μm, 12.0 μm, 12.5 μm, 13.0 μm, 13.5 μm, 14.0 μm, 14.5 μm, 15.0 μm, or any value between 10.0 μm and 15.0 μm.

[0041] The BET of the high-nickel hydroxide is 5 m. 2 / g-30 m 2 / g. For example, the BET of high-nickel hydroxide is 5 m. 2 / g、6m 2 / g、7 m 2 / g、8m 2 / g、9 m 2 / g、10 m 2 / g、11 m 2 / g、12 m 2 / g、13 m 2 / g、14 m 2 / g、15 m 2 / g、16 m 2 / g、17 m 2 / g、18 m 2 / g、19 m 2 / g、20 m 2 / g、21 m 2 / g、22 m 2 / g、23 m 2 / g、24 m 2 / g、25 m 2 / g、26 m 2 / g、27 m 2 / g、28 m 2 / g、29 m 2 / g、30 m2 / g or 5 m 2 / g-30 m 2 Any value between / g.

[0042] The tap density (TD) of the high-nickel hydroxide is 1.8 g / cm³. 3 -2.1g / cm 3 For example, the tap density (TD) of high-nickel hydroxide is 1.80 g / cm³. 3 1.85g / cm 3 1.90g / cm 3 1.95g / cm 3 2.00 g / cm 3 2.05g / cm 3 2.10 g / cm 3 Or 1.8g / cm 3 -2.1g / cm 3 Any value between.

[0043] This application also provides a method for preparing the high-nickel hydroxide as described above, comprising: Preparation of seed crystals: A metal salt suspension, a precipitant solution, and a complexing agent solution are introduced into a first base solution containing a precipitant and a complexing agent to carry out a first coprecipitation reaction until the particle size of precipitate 1 reaches the first particle size. After collecting precipitate 1 and performing post-processing, seed crystals are obtained. Seed crystal growth: The seed crystal is added to the second base solution containing the precipitant and the complexing agent, and then the metal salt suspension, the precipitant solution and the complexing agent solution are added to carry out the second coprecipitation reaction until the particle size of precipitate 2 reaches the second particle size. The precipitate 2 is collected and post-processed to obtain the high nickel hydroxide. The metal salt suspension includes nickel salt, cobalt salt, manganese salt, and doped compounds, wherein the doped compounds include tungstate, Mo oxide, and organic Nb salt; In the metal salt suspension, W accounts for 0.0005-0.05 of the total molar amount of metal; for example, W in the metal salt suspension accounts for any value between 0.0005, 0.01, 0.02, 0.03, 0.04, 0.05, or 0.0005-0.05 of the total molar amount of metal.

[0044] In the metal salt suspension, Mo accounts for 0.0005-0.05 of the total metal molar amount; for example, the Mo content in the metal salt suspension can be any value between 0.0005, 0.01, 0.02, 0.03, 0.04, 0.05, or 0.0005-0.05 of the total metal molar amount.

[0045] In the metal salt suspension, Nb accounts for 0.0005-0.05 of the total molar amount of metal. For example, the Nb content in the metal salt suspension can be any value between 0.0005, 0.01, 0.02, 0.03, 0.04, 0.05, or between 0.0005 and 0.05 of the total molar amount of metal.

[0046] Nickel salts, cobalt salts, and manganese salts are chloride salts or sulfate salts.

[0047] Tungstates include, but are not limited to, sodium tungstate; oxides of Mo include, but are not limited to, molybdenum trioxide; and organic Nb salts include, but are not limited to, niobium oxalate.

[0048] In co-precipitation reactions, adding specific amounts of W, Mo, Nb, etc. for co-doping can improve the uniformity of doping.

[0049] In some embodiments, the doping compound further includes an M source, which includes at least one of a Zr salt, an oxyacid salt of Ti, and an organic Sb salt; wherein the Zr salt includes, but is not limited to, zirconium sulfate, the oxyacid salt of Ti includes, but is not limited to, titanium oxysulfate, and the organic Sb salt includes, but is not limited to, sodium antimony tartrate.

[0050] In the metal salt suspension, Zr accounts for 0-0.05 of the total metal molar amount; for example, Zr accounts for 0, 0.01, 0.02, 0.03, 0.04, 0.05 or any value between 0 and 0.05 of the total metal molar amount in the metal salt suspension.

[0051] In the metal salt suspension, Ti accounts for 0-0.05 of the total molar amount of metal; for example, Ti accounts for 0, 0.01, 0.02, 0.03, 0.04, 0.05 or any value between 0 and 0.05 of the total molar amount of metal.

[0052] In the metal salt suspension, Sb accounts for 0-0.05 of the total molar amount of metal. For example, the Sb content in the metal salt suspension can be 0, 0.01, 0.02, 0.03, 0.04, 0.05, or any value between 0 and 0.05.

[0053] The aforementioned metal salt suspension is an aqueous suspension containing dissolved metal salts and slightly soluble or sparingly soluble metal compounds. In actual preparation, the metal salt suspension must be prepared and used immediately to prevent hydrolysis of some components.

[0054] In some embodiments, the precipitant includes sodium hydroxide; The complexing agent includes ammonia; The pH value of the first base solution is 11.0-11.4; for example, the pH value of the first base solution is 11.0, 11.1, 11.2, 11.3, 11.4 or any value between 11.0 and 11.4.

[0055] The ammonia concentration of the first base solution is 3.0 g / L to 5.0 g / L; for example, the ammonia concentration of the first base solution is any value between 3.0 g / L, 3.1 g / L, 3.2 g / L, 3.3 g / L, 3.4 g / L, 3.5 g / L, 3.6 g / L, 3.7 g / L, 3.8 g / L, 3.9 g / L, 4 g / L, 4.1 g / L, 4.2 g / L, 4.3 g / L, 4.4 g / L, 4.5 g / L, 4.6 g / L, 4.7 g / L, 4.8 g / L, 4.9 g / L, 5.0 g / L, or between 3.0 g / L and 5.0 g / L.

[0056] Different metal elements precipitate with varying pH values, precipitation rates, and complexing abilities with complexing agents. By adjusting the pH value and ammonia concentration of the first base solution, the seed formation rate at the beginning of the coprecipitation reaction and the uniformity of distribution of each dopant element in the seed crystal can be affected.

[0057] During the first coprecipitation reaction, the pH of the reaction system was 9.0-10.8; For example, the pH value of the reaction system during the first coprecipitation reaction can be any value between 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, or 9.0-10.8.

[0058] During the first coprecipitation reaction, the ammonia concentration in the reaction system was 1.0 g / L - 6.0 g / L; For example, the ammonia concentration in the reaction system during the first coprecipitation reaction can be any value between 1.0 g / L, 1.5 g / L, 2.0 g / L, 2.5 g / L, 3.0 g / L, 3.5 g / L, 4.0 g / L, 4.5 g / L, 5.0 g / L, 5.5 g / L, 6.0 g / L, or 1.0 g / L to 6.0 g / L.

[0059] In the seed crystal preparation step, the flow rate of the metal salt suspension added to the first base liquid is 7%-9% of the reaction vessel volume. For example, the flow rate of the metal salt suspension added to the first base liquid can be any value between 7.0% / h, 7.2% / h, 7.4% / h, 7.6% / h, 7.8% / h, 8.0% / h, 8.2% / h, 8.4% / h, 8.6% / h, 8.8% / h, 9.0% / h or 7% / h-9% / h of the reaction vessel volume.

[0060] In the first coprecipitation reaction, if the flow rate of the metal salt suspension is too slow, although the doping uniformity is good, the amount of seed crystals generated is small, the growth rate is slow, the seed crystal tap density is high, and the specific surface area is low. If the flow rate of the metal salt suspension is too fast, the doping uniformity is poor, and too many small seed crystals are easily generated, which is not conducive to controlling the uniformity of the seed crystal size.

[0061] The temperature of the first coprecipitation reaction is 50℃-64℃; For example, the temperature of the first coprecipitation reaction is any value between 50°C, 52°C, 54°C, 56°C, 58°C, 60°C, 62°C, 64°C, or 50°C-64°C.

[0062] The stirring speed for the first coprecipitation reaction is 600 r / min to 1200 r / min.

[0063] For example, the stirring speed for the first coprecipitation reaction is any value between 600 r / min, 700 r / min, 800 r / min, 900 r / min, 1000 r / min, 1100 r / min, 1200 r / min, or 600 r / min - 1200 r / min.

[0064] In the first coprecipitation reaction, if the stirring speed is too slow, it will affect the uniformity of doping; if the stirring speed is too fast, the first coprecipitation reaction rate will be faster, and a large number of new seed crystals will be generated. The stirring speed of the first coprecipitation reaction is faster than that of the second coprecipitation reaction.

[0065] In some embodiments, the first particle size is 4μm-6μm.

[0066] For example, the first particle size can be 4μm, 4.5μm, 5μm, 5.5μm, 6μm, or any value between 4μm and 6μm. The first particle size is the particle size of the seed crystal. Controlling the seed crystal particle size is beneficial for controlling the uniformity of the particle size of the final product.

[0067] In some embodiments, the pH value of the second substrate is 9.0-10.5; for example, the pH value of the second substrate is 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10, 10.1, 10.2, 10.3, 10.4, 10.5, or any value between 9.0 and 10.5.

[0068] The ammonia concentration of the second base solution is 1.0 g / L-5.5 g / L; the ammonia concentration of the second base solution is any value between 1.0 g / L, 1.5 g / L, 2.0 g / L, 2.5 g / L, 3.0 g / L, 3.5 g / L, 4.0 g / L, 4.5 g / L, 5.0 g / L, 5.5 g / L or 1.0 g / L-5.5 g / L.

[0069] The pH of the reaction system during the second coprecipitation reaction is 9.0-10.8. For example, the pH of the reaction system during the second coprecipitation reaction can be any value between 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, or 9.0-10.8.

[0070] When the second coprecipitation reaction is carried out, the ammonia concentration in the reaction system is 1.0 g / L to 6.0 g / L. For example, the ammonia concentration in the reaction system when carrying out the second coprecipitation reaction can be any value between 1.0 g / L, 1.5 g / L, 2.0 g / L, 2.5 g / L, 3.0 g / L, 3.5 g / L, 4.0 g / L, 4.5 g / L, 5.0 g / L, 5.5 g / L, 6.0 g / L, or 1.0 g / L to 6.0 g / L.

[0071] In the second coprecipitation reaction stage, while ensuring doping uniformity, the pH value of the reaction system will be lower and the ammonia concentration will be higher, which will inhibit the generation of new seed crystals and promote the continued growth of seed crystals.

[0072] In the seed crystal growth step, the flow rate of the metal salt suspension added to the second base liquid is 7%-9% of the reaction vessel volume; for example, the flow rate of the metal salt suspension added to the second base liquid can be any value between 7.0%, 7.2%, 7.4%, 7.6%, 7.8%, 8.0%, 8.2%, 8.4%, 8.6%, 8.8%, 9.0%, or 7%-9% of the reaction vessel volume. In the second co-precipitation reaction, if the flow rate of the metal salt suspension is too slow, although the doping uniformity is good, the secondary particle growth is too slow; while if the flow rate of the metal salt suspension is too fast, the doping uniformity is poor.

[0073] The temperature for the second coprecipitation reaction is 65℃-75℃; For example, the temperature of the second coprecipitation reaction is 65°C, 70°C, 75°C, or any value between 65°C and 75°C.

[0074] The stirring speed for the second coprecipitation reaction is 200 r / min to 500 r / min.

[0075] For example, the stirring speed for the second coprecipitation reaction can be any value between 200 r / min, 250 r / min, 300 r / min, 350 r / min, 400 r / min, 450 r / min, 500 r / min, or 200 r / min-500 r / min. In the second coprecipitation reaction, if the stirring speed is too slow, it will affect the uniformity of doping; if the stirring speed is too fast, it will affect the continued growth of the seed crystals.

[0076] The second particle size is 10μm-15μm.

[0077] For example, the second particle size is 10μm, 11μm, 12μm, 13μm, 14μm, 15μm or any value between 10μm and 15μm.

[0078] Both the first coprecipitation reaction and the second coprecipitation reaction were carried out under inert gas protection. In some embodiments, in the step of preparing seed crystals, the post-processing includes: centrifuging and drying the precipitate 1.

[0079] In the seed crystal growth step, the post-processing includes: centrifuging the precipitate 2 to remove excess water, and sequentially washing, drying, sieving, and demagnetizing.

[0080] Based on the ratio of different metal elements, the precipitation rate and doping uniformity are controlled by precisely controlling parameters such as pH value and ammonia concentration in the first base liquid, the second base liquid, the first coprecipitation reaction, and the second coprecipitation reaction.

[0081] In conventional reactions, the pH value in the first coprecipitation reaction is higher than that in the second coprecipitation reaction, and the flow rate of the metal salt suspension in the first coprecipitation reaction is lower than that in the second coprecipitation reaction. However, in order to obtain high-nickel hydroxide with coefficients of variation of W, Mo, and Nb concentrations all <20%, this application controls the flow rate, pH value, and ammonia concentration of the metal salt suspensions in both the first and second coprecipitation reactions to be consistent.

[0082] In some embodiments, the difference in flow rate between the metal salt suspension in the first coprecipitation reaction and the second coprecipitation reaction is less than or equal to 0.5% / h; for example, the difference in flow rate between the metal salt suspension in the first coprecipitation reaction and the second coprecipitation reaction is 0, 0.1% / h, 0.2% / h, 0.3% / h, 0.4% / h, 0.5% / h, or any value less than or equal to 0.5% / h.

[0083] In some embodiments, the difference between the pH value of the first coprecipitation reaction and the pH value of the second coprecipitation reaction is less than or equal to 0.2; for example, the difference between the pH value of the first coprecipitation reaction and the pH value of the second coprecipitation reaction is 0, 0.1, 0.2 or any value less than or equal to 0.2.

[0084] In some embodiments, the difference between the ammonia concentration in the first coprecipitation reaction and the ammonia concentration in the second coprecipitation reaction is less than or equal to 0.5 g / L; for example, the difference between the ammonia concentration in the first coprecipitation reaction and the ammonia concentration in the second coprecipitation reaction is 0, 0.1 g / L, 0.2 g / L, 0.3 g / L, 0.4 g / L, 0.5 g / L, or any value less than or equal to 0.5 g / L.

[0085] This application also provides a cathode material, which is prepared by sintering a mixture of high-nickel hydroxide and a lithium source; The high-nickel hydroxide is either the high-nickel hydroxide described above or a high-nickel hydroxide prepared by the preparation method described above.

[0086] This application also provides a lithium-ion battery, including the positive electrode material described above.

[0087] This application also provides an electrical device, including the lithium-ion battery described above.

[0088] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0089] The test methods for the cathode material precursors involved in this application are as follows: D50: Measured using a laser particle size analyzer (instrument model: Mastersizer 3000), in accordance with the national standard GB / T 19077-2016 Particle size analysis by laser diffraction. BET (Specific Surface Area): Measured using 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"; TD (Tap Density): Measured using 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".

[0090] Total content of nickel, cobalt, manganese, tungsten, molybdenum, niobium, zirconium, titanium, and antimony: determined by inductively coupled plasma mass spectrometry (instrument model: Agilent 7850 ICP-MS), referring to the national standard GB / T 8647.11-2019 Chemical analysis methods for nickel - Part 11: Determination of the content of magnesium, aluminum, manganese, cobalt, copper, zinc, cadmium, tin, antimony, lead, and bismuth by inductively coupled plasma mass spectrometry.

[0091] Concentration distribution and coefficient of variation calculation of nickel, cobalt, manganese, tungsten, molybdenum, niobium, zirconium, titanium, and antimony: Measurements were performed using a field emission scanning electron microscope (SEM) combined with an X-ray energy dispersive spectrometer (EDS). Referring to national standards GB / T 17359-2023 Quantitative Analysis of Elements with Atomic Numbers Not Less Than 11 by Energy Dispersive Spectroscopy and GB / T 25189-2010 Determination of Parameters for Quantitative Analysis by Scanning Electron Microscopy and Energy Dispersive Spectroscopy (SEM-EDS), intensity values ​​were acquired by line scanning or area scanning of the precursor secondary particles after epoxy resin cold mounting and polishing to expose the cross-section. Then, distribution maps of each target metal element were plotted based on the intensity values. Area scanning was as follows: Figure 2 In 2(b)-2(d), line scan as follows Figure 4 As shown in 4(a)-4(i), where N≥100, the intensity values ​​collected by the EDS can be used as quantitative parameters to characterize the concentration distribution of the target metal element within the secondary particles. The coefficient of variation calculated based on the intensity values ​​can effectively reflect the uniformity of the target metal element distribution. The test conditions were: accelerating voltage (Acc V): 20.0kV, aperture (Aperture): 4 (053e-008A), corresponding current: approximately 53 nA.

[0092] It is important to note that when the electron beam (SEM beam) scans the physical edges of secondary particles, the significant difference in electron density between the sample and the background (usually conductive adhesive or resin) causes strong edge scattering, resulting in... Figure 4 The rapid rising and falling segments on both sides of the curves shown in 4(a)-4(i) are considered invalid data and should be removed when calculating the coefficient of variation.

[0093] For example, the target metallic elements are Ni, Co, Mn, W, Mo, Nb, and optionally M.

[0094] For example, the magnification of the SEM image of the cross-section of the precursor secondary particles during testing can be 7.0K, 9.0K, 10.0K, 12.0K, 15.0K, etc. The specific magnification should be such that there is only one complete or nearly complete single secondary particle spherical cross-section in the SEM field of view.

[0095] For example, the sample of Example 1 was processed to obtain Figure 2 The secondary particle cross section shown in 2(a) is then scanned along with the entire secondary particle cross section and adjacent regions. The resulting surface scan images of the W, Mo, and Nb element concentrations are shown below. Figure 2 As shown in 2(b)-2(d) in the figure.

[0096] For example, the sample of Example 6 was processed to obtain Figure 3 The secondary particle cross-section shown is as follows: Figure 3 As shown, a red straight line region to be scanned is first set along the diameter direction of the secondary particle cross-section, from the left side to the right side of the secondary particle. Then, the leftmost horizontal coordinate of the red straight line region is set to 0 μm, and 328 sampling points are set at equal intervals of 0.06 μm. After scanning and processing according to each sampling point, the intensity value of each target metal element (Ni, Co, Mn, W, Mo, Nb, Zr, Ti, Sb) is obtained. Finally, the above intensity values ​​are used to create an elemental distribution map, as shown below. Figure 4 As shown in 4(a)-4(i).

[0097] For example, in Example 6, the sample was scanned using a line scan. The calculation process for the coefficient of variation of the concentration distribution of each target metal element was as follows: ① First, select data within the defined analysis area that meets the requirements (a straight area extending radially through the geometric center of the secondary particle cross-section and extending to both sides by 0.8 times the radius of the secondary particle (0.8r)). Specifically, the SEM image of the secondary particle cross-section and the schematic diagram of the line scan area of ​​the high-nickel hydroxide sample in Example 6 are shown below. Figure 3 As shown, measurements were taken at... Figure 3 Within the red straight line region, the distance from the leftmost edge of the red straight line region to the left edge of the secondary particle cross-section is 3.643 μm. The diameter of the secondary particle cross-section is approximately 12.34 μm. Therefore: The radius r of the secondary particle cross section is 12.34 μm ÷ 2 = 6.17 μm; The 0.8r of the secondary particle cross section is 0.8 × 6.17 μm = 4.936 μm; The shortest distance from the 0.8r edge of the secondary particle cross section to the two edges of the secondary particle is 6.17μm - 4.936μm = 1.234μm; The initial x-coordinate of the sampling point in the line scan defined analysis area = the shortest distance from the leftmost part of the red straight line area to the left edge of the secondary particle cross section + the shortest distance from the left edge of the secondary particle cross section to the 0.8r edge = 3.643μm + 1.234μm = 4.877μm; however, there is no x-coordinate of 4.877μm for the sampling point, so the closest x-coordinate of 4.86μm is selected. The final x-coordinate of the sampling point = the initial x-coordinate of the sampling point + 2 × 0.8r of the secondary particle = 4.877μm + 2 × 4.936μm = 14.749μm. However, there is no x-coordinate of 14.749 for the sampling point, so the closest x-coordinate of 14.76μm is selected. Specifically, 166 equally spaced sampling points were selected within the x-axis range of 4.86 μm to 14.76 μm to collect the signal intensities of nine target metallic elements. The data were categorized by element type to construct nine independent intensity value datasets.

[0098] ② Calculate the coefficient of variation of the concentration distribution of each target metal element based on the dataset. The calculation formula is as follows: ; Where: CV is the coefficient of variation of the intensity value corresponding to the concentration distribution of a certain target metal element; σ—the standard deviation of the intensity values ​​of a target metallic element acquired by EDS scanning; —The average intensity value of a certain target metal element acquired by EDS scanning; N—The total number of intensity values ​​of a certain target metal element acquired by EDS scanning; i—the index of the intensity value of a certain target metal element acquired by EDS scanning, i = 1, 2...... N; xi — the i-th intensity value of a target metallic element acquired by EDS scanning.

[0099] Test method for compressive strength: Refer to the test method for powder compressive strength (GB / T 43091-2023) for testing.

[0100] Example 1 (1) Preparation of solution: Mix nickel sulfate, cobalt sulfate, manganese sulfate, sodium tungstate, molybdenum trioxide, niobium oxalate and pure water and stir well. Prepare a metal salt suspension according to the molar ratio Ni:Co:Mn:W:Mo:Nb=0.967:0.005:0.025:0.001:0.001:0.001, with a total mass concentration of 120 g / L. Prepare a sodium hydroxide solution with a solute mass fraction of 32.5 wt% and an ammonia solution with a solute mass fraction of 20 wt%.

[0101] (2) Preparation of seed crystals: Pure water, sodium hydroxide solution, and ammonia solution were added to the reactor to prepare a first base solution with a pH of 11.2 and a free ammonia concentration of 3.5 g / L. Nitrogen gas was introduced as a protective gas. Metal salt suspension, sodium hydroxide solution, and ammonia water were introduced into the reactor to carry out the first coprecipitation reaction. The flow rate of the metal salt suspension added to the first base solution was controlled to be 8.0% / h-8.5% / h of the reactor volume. The pH of the first coprecipitation reaction was 9.3-9.5, the reaction temperature was 60℃, the free ammonia concentration was 1.5 g / L-2.0 g / L, and the stirring speed was 900 r / min. When the particle size of precipitate 1 reached about 5 μm, the feeding was stopped, precipitate 1 was collected, centrifuged and dried to obtain seed crystals.

[0102] (3) Seed crystal growth: Pure water, sodium hydroxide solution, and ammonia solution were added to the reactor to prepare a second base solution with a pH of 9.3 and a free ammonia concentration of 1.5 g / L. Seed crystals were then added, and nitrogen gas was introduced as a protective gas. A metal salt suspension, sodium hydroxide solution, and ammonia water were then introduced into the reactor to carry out the second coprecipitation reaction. The flow rate of the metal salt suspension added to the second base solution was controlled to be 8.0%-8.5% / h of the reactor volume. The pH of the second coprecipitation reaction was 9.3-9.5, the reaction temperature was 70℃, the free ammonia concentration was 1.5 g / L-2.0 g / L, and the stirring speed was 360 r / min. Feeding was stopped when the particle size of precipitate 2 reached approximately 12 μm. Precipitate 2 was collected, centrifuged, and then washed, dried, sieved, demagnetized, and packaged to obtain high-nickel hydroxide Ni. 0.967 Co 0.005 Mn 0.025 W 0.001 Mo 0.001 Nb 0.001 (OH)2.

[0103] Surface SEM image of high-nickel hydroxide in Example 1 is shown below. Figure 1 As shown.

[0104] Example 2 The preparation method of Example 2 differs from that of Example 1 in that: (2) Preparation of seed crystals: The pH value of the first coprecipitation reaction is controlled to be 9.8-10.0, and the free ammonia concentration is 3.5g / L-4.0g / L.

[0105] (3) Seed growth: control the pH of the second base solution to 9.8 and the free ammonia concentration to 3.5 g / L; control the pH of the second coprecipitation reaction to 9.8-10.0 and the free ammonia concentration to 3.5 g / L-4.0 g / L.

[0106] Example 3 The preparation method of Example 3 differs from that of Example 1 in that: (2) Preparation of seed crystals: The pH value of the first coprecipitation reaction is controlled to be 10.2-10.4, and the free ammonia concentration is 5.0g / L-5.5g / L.

[0107] (3) Seed growth: control the pH of the second base solution to 10.2 and the free ammonia concentration to 5 g / L; control the pH of the second coprecipitation reaction to 10.2-10.4 and the free ammonia concentration to 5.0 g / L-5.5 g / L. Example 4 The preparation method of Example 4 differs from that of Example 1 in that: (1) Preparation of solution: Mix nickel sulfate, cobalt sulfate, manganese sulfate, sodium tungstate, molybdenum trioxide, niobium oxalate, zirconium sulfate and pure water. Prepare a metal salt suspension according to the molar ratio Ni:Co:Mn:W:Mo:Nb:Zr=0.966:0.005:0.025:0.001:0.001:0.001:0.001. The total mass concentration of the metal salts is 120 g / L.

[0108] (2) Preparation of seed crystals: The pH value of the first coprecipitation reaction is controlled to be 10.3-10.5, and the free ammonia concentration is 5.0g / L-5.5g / L.

[0109] (3) Seed growth: control the pH of the second base solution to 10.3 and the free ammonia concentration to 5.0 g / L; control the pH of the second coprecipitation reaction to 10.3-10.5 and the free ammonia concentration to 5.0 g / L-5.5 g / L.

[0110] Example 5 The preparation method of Example 5 differs from that of Example 1 in that: (1) Preparation of solution: Mix nickel sulfate, cobalt sulfate, manganese sulfate, sodium tungstate, molybdenum trioxide, niobium oxalate, zirconium sulfate, titanium oxysulfate and pure water. Prepare a metal salt suspension according to the molar ratio Ni:Co:Mn:W:Mo:Nb:Zr:Ti=0.965:0.005:0.025:0.001:0.001:0.001:0.001:0.001. The total mass concentration of the metal salts is 120 g / L.

[0111] (2) Preparation of seed crystals: The pH value of the first coprecipitation reaction is controlled to be 10.4-10.6, and the free ammonia concentration is 5.0g / L-5.5g / L.

[0112] (3) Seed growth: control the pH of the second base solution to 10.4 and the free ammonia concentration to 5.0 g / L; control the pH of the second coprecipitation reaction to 10.4-10.6 and the free ammonia concentration to 5.0 g / L-5.5 g / L.

[0113] Example 6 The preparation method of Example 6 differs from that of Example 1 in that: (1) Solution preparation: Mix nickel sulfate, cobalt sulfate, manganese sulfate, sodium tungstate, molybdenum trioxide, niobium oxalate, zirconium sulfate, titanium oxysulfate, sodium antimony tartrate and pure water. Prepare a metal salt suspension according to the molar ratio Ni:Co:Mn:W:Mo:Nb:Zr:Ti:Sb=0.964:0.005:0.025:0.001:0.001:0.001:0.001:0.001:0.001:0.001. The total mass concentration of the metal salts is 120 g / L.

[0114] (2) Preparation of seed crystals: The pH value of the first coprecipitation reaction is controlled to be 10.5-10.7, and the free ammonia concentration is 5.0g / L-5.5g / L.

[0115] (3) Seed growth: control the pH of the second base solution to 10.5 and the free ammonia concentration to 5.0 g / L; control the pH of the second coprecipitation reaction to 10.5-10.7 and the free ammonia concentration to 5.0 g / L-5.5 g / L.

[0116] Example 7 The preparation method of Example 7 differs from that of Example 1 in that: (2) Preparation of seed crystals: The pH value of the first coprecipitation reaction is controlled to be 10.2-10.4, and the free ammonia concentration is 5.0g / L-5.5g / L.

[0117] (3) Seed growth: control the pH of the second base solution to 10.2 and the free ammonia concentration to 5.0 g / L; control the pH of the second coprecipitation reaction to 10.2-10.4 and the free ammonia concentration to 5.0 g / L-5.5 g / L.

[0118] Example 8 The preparation method of Example 8 differs from that of Example 1 in that: (1) Preparation of solution: Mix nickel sulfate, cobalt sulfate, manganese sulfate, sodium tungstate, molybdenum trioxide, niobium oxalate and pure water and stir well. Prepare a metal salt suspension according to the molar ratio Ni:Co:Mn:W:Mo:Nb=0.9694:0.005:0.025:0.001:0.0015:0.0005. The total mass concentration of the metal salts is 120g / L.

[0119] (2) Preparation of seed crystals: The pH value of the first coprecipitation reaction is controlled to be 10.2-10.4, and the free ammonia concentration is 5.0g / L-5.5g / L.

[0120] (3) Seed growth: control the pH of the second base solution to 10.2 and the free ammonia concentration to 5.0 g / L; control the pH of the second coprecipitation reaction to 10.2-10.4 and the free ammonia concentration to 5.0 g / L-5.5 g / L.

[0121] Comparative Example 1 The difference between the preparation method of Comparative Example 1 and Example 1 is as follows: (1) Preparation of solution: Mix nickel sulfate, cobalt sulfate, manganese sulfate, sodium tungstate and pure water and stir well. Prepare a metal salt suspension according to the molar ratio Ni:Co:Mn:W=0.969:0.005:0.025:0.001. The total mass concentration of the metal salts is 120g / L.

[0122] (2) Preparation of seed crystals: The pH value of the first coprecipitation reaction is controlled to be 10.2-10.4, and the free ammonia concentration is 5.0g / L-5.5g / L.

[0123] (3) Seed growth: control the pH of the second base solution to 10.2 and the free ammonia concentration to 5.0 g / L; control the pH of the second coprecipitation reaction to 10.2-10.4 and the free ammonia concentration to 5.0 g / L-5.5 g / L.

[0124] Comparative Example 2 The difference between the preparation method of Comparative Example 2 and Example 1 is as follows: (1) Preparation of solution: Mix nickel sulfate, cobalt sulfate, manganese sulfate, sodium tungstate, niobium oxalate and pure water and stir well. Prepare a metal salt suspension according to the molar ratio Ni:Co:Mn:W:Nb=0.968:0.005:0.025:0.001:0.001. The total mass concentration of the metal salts is 120g / L.

[0125] (2) Preparation of seed crystals: The pH value of the first coprecipitation reaction is controlled to be 10.1-10.3, and the free ammonia concentration is 5.0g / L-5.5g / L.

[0126] (3) Seed growth: control the pH of the second base solution to 10.1 and the free ammonia concentration to 5.0 g / L; control the pH of the second coprecipitation reaction to 10.1-10.3 and the free ammonia concentration to 5.0 g / L-5.5 g / L.

[0127] Comparative Example 3 The difference between the preparation method of Comparative Example 3 and Example 1 is as follows: (1) Preparation of solution: Mix nickel sulfate, cobalt sulfate, manganese sulfate, zirconium sulfate, titanium oxysulfate, sodium antimony tartrate and pure water. Prepare a metal salt suspension according to the molar ratio Ni:Co:Mn:Zr:Ti:Sb=0.967:0.005:0.025:0.001:0.001:0.001. The total mass concentration of the metal salts is 120g / L.

[0128] (2) Preparation of seed crystals: The pH value of the first coprecipitation reaction is controlled to be 10.2-10.4, and the free ammonia concentration is 5.0g / L-5.5g / L.

[0129] (3) Seed growth: control the pH of the second base solution to 10.2 and the free ammonia concentration to 5.0 g / L; control the pH of the second coprecipitation reaction to 10.2-10.4 and the free ammonia concentration to 5.0 g / L-5.5 g / L.

[0130] Comparative Example 4 The difference between the preparation method of Comparative Example 4 and Example 1 is as follows: (1) Preparation of solution: Mix nickel sulfate, cobalt sulfate, manganese sulfate, sodium tungstate, molybdenum trioxide, niobium oxalate and pure water and stir well. Prepare a metal salt suspension according to the molar ratio Ni:Co:Mn:W:Mo:Nb=0.9694:0.005:0.025:0.0002:0.0002:0.0002. The total mass concentration of the metal salts is 120g / L.

[0131] (2) Preparation of seed crystals: The pH value of the first coprecipitation reaction is controlled to be 10.1-10.3, and the free ammonia concentration is 5.0g / L-5.5g / L.

[0132] (3) Seed growth: control the pH of the second base solution to 10.1 and the free ammonia concentration to 5.0 g / L; control the pH of the second coprecipitation reaction to 10.1-10.3 and the free ammonia concentration to 5.0 g / L-5.5 g / L.

[0133] Comparative Example 5 The difference between the preparation method of Comparative Example 5 and Example 1 is as follows: (1) Preparation of solution: Mix nickel sulfate, cobalt sulfate, manganese sulfate, sodium tungstate, molybdenum trioxide, niobium oxalate and pure water and stir well. Prepare a metal salt suspension according to the molar ratio Ni:Co:Mn:W:Mo:Nb=0.79:0.005:0.025:0.06:0.06:0.06. The sum of the mass concentrations of the metal salts is 120g / L.

[0134] (2) Preparation of seed crystals: The pH value of the first coprecipitation reaction is controlled to be 10.5-10.7, and the free ammonia concentration is 6.0g / L-6.5g / L.

[0135] (3) Seed growth: The flow rate of the metal salt suspension added to the second base liquid is controlled to be 12.0%-12.5% ​​of the reaction vessel volume, the pH value of the second base liquid is 10.5 and the free ammonia concentration is 6.0 g / L; the pH value of the second coprecipitation reaction is controlled to be 10.5-10.7 and the free ammonia concentration is 6.0 g / L-6.5 g / L.

[0136] Comparative Example 6 The difference between the preparation method of Comparative Example 6 and Example 1 is as follows: (2) Preparation of seed crystals: The flow rate of the metal salt suspension added to the first base liquid is controlled to be 10.0% / h-10.5% / h of the reaction vessel volume, the pH value of the first coprecipitation reaction is 9.4-9.6, and the free ammonia concentration is 3.5g / L-4.0g / L.

[0137] (3) Seed growth: control the pH of the second base solution to 9.4 and the free ammonia concentration to 3.5 g / L; control the pH of the second coprecipitation reaction to 9.4-9.6 and the free ammonia concentration to 3.5 g / L-4.0 g / L.

[0138] Comparative Example 7 The difference between the preparation method of Comparative Example 7 and Example 1 is as follows: (1) Preparation of solution: Mix nickel sulfate, cobalt sulfate, manganese sulfate and pure water and stir well. Prepare a metal salt suspension according to the molar ratio of Ni:Co:Mn=0.97:0.005:0.025. The total mass concentration of the metal salts is 120g / L.

[0139] (2) Preparation of seed crystals: The pH value of the first coprecipitation reaction is controlled to be 10.0-10.2, and the free ammonia concentration is 5.0g / L-5.5g / L.

[0140] (3) Seed growth: control the pH of the second base solution to 10.0 and the free ammonia concentration to 5.0 g / L; control the pH of the second coprecipitation reaction to 10.0-10.2 and the free ammonia concentration to 5.0 g / L-5.5 g / L.

[0141] Table 1 Physicochemical properties of each embodiment and comparative example

[0142] Table 2 Physicochemical properties of each embodiment and comparative example

[0143] II. Electrochemical Performance Testing To verify the performance advantages of the cathode material precursors prepared in each embodiment and comparative example, cathode materials were prepared using the cathode material precursors prepared in each embodiment and comparative example as raw materials. The preparation process of each cathode material is as follows: The cathode material precursors prepared in each embodiment and comparative example were mixed with lithium hydroxide. The molar ratio of Li:(Ni+Co+Mn) in the lithium-mixed material was 1.05:1. The lithium-mixed material was then heated to 500°C in oxygen at a rate of 2°C / min and held for 2 hours. The temperature was then increased to 750°C at a rate of 1°C / min and held for 8 hours to sinter into a polycrystalline cathode material.

[0144] Furthermore, the cathode materials prepared from the cathode material precursors of each embodiment and comparative example were assembled into button-type half-cells for electrochemical performance testing. The preparation process of the button-type half-cells is as follows: The positive electrode materials obtained from the positive electrode material precursors of the above embodiments and comparative examples were mixed with conductive acetylene black and polytetrafluoroethylene (PVDF) binder (prepared as an 8wt% PVDF / NMP solution) at a mass ratio of 8:1:1. The mixture was coated on aluminum foil to form a positive electrode sheet. The negative electrode sheet was a lithium metal sheet. The electrolyte was a 1mol / L LiPF6 / EC:DMC solution (volume ratio 1:1). The battery casing, positive and negative electrode sheets, separator (Celgard-2325), spring sheet, gasket, and electrolyte were assembled into a CR-2032 type half cell in a vacuum glove box.

[0145] The electrochemical performance of each CR-2032 half-cell was tested using the Blue Electric testing system. Specifically, charge-discharge tests were conducted at room temperature with a voltage window of 2.5-4.3V. The discharge specific capacity at 0.2C and 2C currents was measured, as well as the capacity retention after 100 cycles at 2C current (1C = 210 mAh / g). The test results are summarized in Table 3 below. Table 3 Performance metrics of each embodiment and comparative example

[0146] The high-nickel hydroxides prepared in Examples 1-8 of this application introduce multiple doping elements, including W, Mo, and Nb, and achieve a uniform distribution of doping elements (low coefficient of variation). All selected doping elements are in a high oxidation state (W). 6+ 、Nb 5+ Mo 4 + Its ionic radius (0.60~0.64 Å) is similar to that of the main transition metal ions (Ni) in high-nickel layered oxides. 2+With a ion size close to 0.69 Å, stable solid solutions can be formed through substitutional doping, avoiding severe lattice distortion caused by ion size mismatch. Simultaneously, in the initial stages of charge and discharge, high-valence elements preferentially provide charge compensation, reducing the need for further oxidation of active ions and thus stabilizing lattice oxygen. During charge and discharge, the uniform expansion and contraction of the lattice with uniform element distribution results in more consistent stress distribution and less susceptibility to cracking. This effectively suppresses particle cracking, structural phase transitions, interfacial side reactions, and transition metal dissolution, resulting in slower capacity decay and higher cycle retention in cathode materials prepared from high-nickel hydroxides during long-term cycling.

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0148] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the foregoing claims, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A high-nickel hydroxide, characterized in that, The chemical formula of the high-nickel hydroxide is Ni x Co y Mn z W a1 Mo a2 Nb a3 M b (OH) 2+σ Wherein, 0.8≤x<1, 0≤y<0.2, 0≤z<0.2, 0.0005≤a1≤0.05, 0.0005≤a2≤0.05, 0.0005≤a3≤0.05, 0≤b≤0.05, x+y+z+a1+a2+a3+b=1, 0≤σ<0.6, and M includes at least one of Zr, Ti, and Sb; The high-nickel hydroxide includes secondary particles formed from primary particles; in the secondary particles, the coefficients of variation of the concentration distribution of W, Mo, and Nb are all <20%.

2. The high-nickel hydroxide according to claim 1, characterized in that, In the secondary particles, the coefficient of variation of Ni concentration distribution is <10%; And / or, in the secondary particles, the coefficient of variation of the Co concentration distribution is <20%; And / or, in the secondary particles, the coefficient of variation of the Mn concentration distribution is <20%; And / or, when b > 0, the coefficient of variation of the concentration distribution of each dopant element in the secondary particles, except for Ni, Co, and Mn, is < 20%.

3. The high-nickel hydroxide according to claim 2, characterized in that, The ratio of the maximum to the minimum subscript value of the dopant element in the chemical formula of the high-nickel hydroxide is greater than or equal to 1 and less than or equal to 2; And / or, the particle size D50 of the high-nickel hydroxide is 10.0 μm to 15.0 μm; And / or, the BET of the high-nickel hydroxide is 5 m 2 / g-30 m 2 / g; And / or, the tap density TD of the high-nickel hydroxide is 1.8 g / cm³. 3 -2.1g / cm 3 .

4. A method for preparing a high-nickel hydroxide as described in any one of claims 1-3, characterized in that, include: Preparation of seed crystals: A metal salt suspension, a precipitant solution, and a complexing agent solution are introduced into a first base solution containing a precipitant and a complexing agent to carry out a first coprecipitation reaction until the particle size of precipitate 1 reaches the first particle size. After post-treatment, seed crystals are obtained. Seed crystal growth: The seed crystal is added to the second base solution containing the precipitant and the complexing agent, and then the metal salt suspension, the precipitant solution and the complexing agent solution are added to carry out the second coprecipitation reaction until the particle size of precipitate 2 reaches the second particle size. The precipitate 2 is collected and post-processed to obtain the high nickel hydroxide. The metal salt suspension includes nickel salt, cobalt salt, manganese salt, and doped compounds, wherein the doped compounds include tungstate, Mo oxide, and organic Nb salt; In the metal salt suspension, W accounts for 0.0005-0.05% of the total molar amount of metal; In the metal salt suspension, Mo accounts for 0.0005-0.05% of the total metal molar amount; In the metal salt suspension, Nb accounts for 0.0005-0.05 of the total metal molar amount.

5. The method for preparing high-nickel hydroxide according to claim 4, characterized in that, The doped compound further includes an M source, which includes at least one of Zr salt, Ti oxoacid salt, and organic Sb salt; In the metal salt suspension, Zr accounts for 0-0.05% of the total metal molar amount; In the metal salt suspension, Ti accounts for 0-0.05% of the total metal molar amount; In the metal salt suspension, Sb accounts for 0-0.05% of the total metal molar amount.

6. The method for preparing high-nickel hydroxide according to claim 4, characterized in that, The precipitant includes sodium hydroxide; The complexing agent includes ammonia; And / or, the pH of the first substrate solution is 11.0-11.

4. And / or, the ammonia concentration of the first base solution is 3.0 g / L-5.0 g / L; And / or, when the first coprecipitation reaction is carried out, the pH value of the reaction system is 9.0-10.8; And / or, when the first coprecipitation reaction is carried out, the ammonia concentration in the reaction system is 1.0 g / L-6.0 g / L; And / or, in the seed crystal preparation step, the flow rate of the metal salt suspension added to the first base liquid is 7% / h-9% / h of the reaction vessel volume; And / or, the temperature of the first coprecipitation reaction is 50℃-64℃; And / or, the stirring speed of the first coprecipitation reaction is 600 r / min-1200 r / min; And / or, the first particle size is 4μm-6μm.

7. The method for preparing high-nickel hydroxide according to claim 4, characterized in that, The pH value of the second substrate solution is 9.0-10.5; And / or, the ammonia concentration of the second substrate is 1.0 g / L - 5.5 g / L; And / or, when carrying out the second coprecipitation reaction, the pH of the reaction system is 9.0-10.8; And / or, when the second coprecipitation reaction is carried out, the ammonia concentration in the reaction system is 1.0 g / L-6.0 g / L; And / or, in the seed crystal growth step, the flow rate of the metal salt suspension added to the second base liquid is 7% / h-9% / h of the reaction vessel volume; And / or, the temperature of the second coprecipitation reaction is 65℃-75℃; And / or, the stirring speed for the second coprecipitation reaction is 200 r / min-500 r / min; And / or, the second particle size is 10 μm-15 μm; And / or, both the first coprecipitation reaction and the second coprecipitation reaction are carried out under inert gas protection.

8. A positive electrode material, characterized in that, The cathode material is prepared by sintering a mixture of high-nickel hydroxide and a lithium source. The high-nickel hydroxide is the high-nickel hydroxide according to any one of claims 1-3 or the high-nickel hydroxide prepared by the preparation method according to any one of claims 4-7.

9. A lithium-ion battery, characterized in that, Includes the cathode material as described in claim 8.

10. An electrical-related device, characterized in that, Including the lithium-ion battery as described in claim 9.

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