Preparation method and application of single-crystal or single-crystal-like ultrahigh-nickel lithium ion battery ternary positive electrode material

Abstract

The invention relates to a preparation method and application of a single-crystal or single-crystal-like ultrahigh-nickel lithium ion battery ternary positive electrode material, and the preparation method comprises the following steps: step 1, dispersing and uniformly mixing a cobalt-nickel-manganese hydroxide ternary precursor, a lithium source and a metal oxide serving as columnar metal ions to obtain a premixed material; carrying out primary sintering on the premixed material, sieving, dispersing and washing to obtain a primary sintering product; 2, urea phosphate and N-methyl pyrrolidone NMP are fully mixed to prepare an in-situ wet coating agent, the primary sintering product and the in-situ wet coating agent are evenly mixed, and then suction filtration, presintering drying and sieving are conducted to obtain a presintering product; and carrying out secondary sintering and secondary sieving dispersion on the pre-sintered product to obtain the single-crystal or single-crystal-like ultrahigh-nickel ternary positive electrode material for the lithium ion battery. The problems of poor structural stability and poor electrochemical performance of a single-crystal or single-crystal-like ultrahigh-nickel lithium ion battery ternary positive electrode material under high voltage in the existing scheme are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and in particular to a method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material and its application. Background Art

[0002] The charging cut-off voltage of high-nickel ternary cathode materials is limited to 4.25V. Further increasing the charging cut-off voltage can increase the energy density of the electrode materials. However, under high charging cut-off voltage, there are many factors that cause the structural stability of the material to decrease and irreversible phase change to occur, resulting in serious capacity attenuation and a sharp decline in cycle performance. The factors are as follows: (1) Cation mixing: As the nickel content increases, Li+ and Ni2+ in high-nickel ternary materials are prone to mixing, that is, the positions of lithium ions and nickel ions in the lattice are interchanged. This mixing will lead to changes in the layered structure, which in turn affects the electrochemical properties and cycle stability of the material. (2) Microcrack generation: During the charging and discharging process, microcracks will be generated inside the particles of high-nickel ternary cathode materials due to the continuous expansion and contraction of the unit cell. These microcracks not only increase the internal resistance, but also intensify the side reactions with the electrolyte, leading to material failure. (3) Surface side reactions: When high-nickel ternary cathode materials come into contact with the electrolyte, surface side reactions will occur, such as the dissolution and deposition of transition metal elements. These side reactions will destroy the SEI film of the negative electrode, resulting in the loss of active lithium and the increase of battery impedance. (4) Poor thermal stability: High nickel ternary positive electrode materials are prone to thermal decomposition under high voltage and high temperature, releasing oxygen and other gases, which not only reduces the thermal stability of the material, but also may cause safety problems. (5) Electrolyte compatibility issues: High nickel ternary positive electrode materials have serious side reactions with traditional fluorinated carbonate-based liquid electrolytes and are thermodynamically unstable. The trace amount of water that is difficult to eliminate in the electrolyte and the corrosive hydrofluoric acid (HF) produced by its reaction with lithium hexafluorophosphate (LiPF6) can easily lead to the dissolution of transition metal ions in high nickel ternary positive electrode materials, surface oxygen evolution and irreversible damage to the positive electrode electrolyte interface (CEI).

[0003] In order to increase the charging cut-off voltage of high-nickel ternary positive electrode materials and thus improve their energy density, this can be achieved through means such as element doping and surface modification. For example, the introduction of elements such as Mg, Al, and Ti for doping can effectively inhibit the structural degradation of the material during the cycle; while surface coating with materials such as carbon and alumina can improve the conductivity of the material and reduce side reactions. In addition to element doping, the sintering process is also an important factor affecting the performance of high-nickel ternary positive electrode materials. By optimizing the sintering temperature and time, the particle size and morphology of the material can be regulated, thereby improving its electrochemical performance. In addition, the use of new synthesis methods such as coprecipitation and sol-gel methods can also help to obtain high-nickel ternary positive electrode materials with excellent performance. However, these methods require the material to be washed with water to reduce the residual alkali residue. Excessive residual alkali in the material will have many negative effects on battery performance, including affecting the coating process, increasing irreversible capacity loss, deteriorating cycle performance, bringing safety risks, and reducing rate and cycle performance. Therefore, a series of measures need to be taken during the production process to effectively reduce the residual alkali content on the surface of the material. The most commonly used method is water washing, but the water washing process parameters are difficult to control and can easily damage the surface structure of the positive electrode material. (1) The water washing solution contains too many impurities or ions, which may react chemically with the surface of the material, resulting in damage to the surface structure of the material; (2) Mechanical effects such as stirring and friction during the water washing process may also damage the surface structure of the material; (3) The temperature and time of the water washing process are also important factors affecting the surface structure of the material. Excessive temperature or too long time may cause the compounds on the surface of the material to dissolve or decompose, thereby destroying the surface structure; (4) The washed material needs to be dried. If the drying temperature is too high or the drying speed is too fast, the water on the surface of the material may evaporate rapidly, resulting in stress concentration, which in turn destroys the surface structure.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] In view of the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material and its application, so as to solve the problems of poor structural stability and poor electrochemical performance of single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode materials in the prior art under high voltage.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] Preparation method of single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material;

[0008] The steps include:

[0009] Step 1: breaking up and uniformly mixing the cobalt hydroxide nickel manganese ternary precursor, the lithium source and the metal oxide acting as the columnar metal ion to obtain a premixed material; sintering the premixed material once, sieving and dispersing it, and washing it with water to obtain a primary sintered product;

[0010] Step 2: Urea phosphate and N-methylpyrrolidone NMP are fully mixed to prepare an in-situ wet coating agent, the primary sintering product is mixed with the in-situ wet coating agent evenly, and then filtered, pre-burned and dried, and sieved to obtain a pre-burned product; the pre-burned product is secondary sintered, and secondary sieving and dispersion is performed to obtain a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material.

[0011] A further technical solution is that in step 1: the molecular formula of the cobalt hydroxide nickel manganese ternary precursor is Co a Ni b Mn 1-a-b (OH)2; wherein the particle size is D50: 2.5-5 μm; the molecular formula of the single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material is [Li x Co a Ni b Mn 1-a-b ]O2; wherein, 1.0<x<1.09.

[0012] A further technical solution is that in step 1: the lithium source molecular formula is one or more of LiOH·H2O, LiOH, Li2CO3, LiCl, LiNO3, and C2H3LiO2.

[0013] A further technical solution is that in step 1: the metal oxide is one or more of strontium oxide, nickel oxide, zinc oxide, manganese oxide, aluminum oxide, rubidium oxide, zirconium oxide, tungsten oxide, molybdenum oxide, magnesium oxide, niobium oxide, titanium oxide, lanthanum oxide, antimony oxide, and yttrium oxide.

[0014] A further technical solution is that the material structure is [Li x Co a Ni b Mn 1-a-b ]O2·L i M y O z ; Wherein, 1.0<x<1.09, 0.04<a<1, 0.04<b<1; M is a metal element within yttrium, zirconium, magnesium, strontium and M y O z It is one or more composite oxides having a valence composition, wherein 0<y<3, 0<z≤3, and 1.9<x+a+b<2.5.

[0015] A further technical solution is that in step 1: the molar ratio of the lithium source to the cobalt nickel manganese hydroxide ternary precursor is 1.00-1.09:1, polyurethane zirconium balls are used as the mixing medium, and the total medium of the cobalt nickel manganese hydroxide ternary precursor, the lithium source and the metal oxide acting as the columnar metal ion: the polyurethane zirconium ball mass ratio is 2:1-1:2; the mass ratio of large balls to small balls in the polyurethane zirconium balls is 2:1-1:2, the mixing time is 2-6 hours, and the mixing speed is 100-300 rpm.

[0016] A further technical solution is that in step 1: the added content of the metal oxide is: 0 PPm<metal oxide≤5000 PPm.

[0017] A further technical solution is that the primary sintering in step 1 includes the following process:

[0018] The premixed materials are loaded into the sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 400-600°C, the heating rate is 2-5°C / min, and the temperature is kept for 2-6 hours;

[0019] The temperature in the sintering furnace is raised to 550-880°C at a rate of 2-5°C / min, and is kept warm for 5-15 hours, and then cooled to room temperature along with the furnace.

[0020] A further technical solution is that in the step 2: the contents of LiOH and Li2CO3 in the primary sintering product are detected, that is, the surface residual alkali content; the molar ratio of the added content of urea phosphate to the surface residual alkali in the in-situ wet coating agent is 1:0.5 to 1:1.5; urea phosphate is added to N-methylpyrrolidone NMP solution to prepare an in-situ wet coating agent with a urea phosphate mass percentage of 2wt%.

[0021] A further technical solution is that in step 2: the primary sintered product is mixed evenly with the in-situ wet coating agent by a water bath heating method through two stirring processes with different parameters;

[0022] The stirring speed of the first stage is 200-1000 r / min, and the stirring time is 1-5 h; the stirring speed of the second stage is 500-1500 r / min, and the stirring time is 5-15 h, and the temperature is 0-300°C.

[0023] A further technical solution is that in step 2: oxygen is introduced into the pre-calcination and drying process and the process is carried out in two stages;

[0024] The first stage of sintering: the temperature is 50-150℃, and the sintering time is 30-200min;

[0025] The second stage of sintering: the temperature is 50-300°C and the sintering time is 500-1000min.

[0026] A further technical solution is that the secondary sintering in step 2 includes the following process:

[0027] The pre-burned product is put into a sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 300-700°C, the heating rate is 2-5°C / min, and the heat is kept for 3-9 hours; and the furnace is cooled to room temperature.

[0028] The single crystal or quasi-single crystal type ultra-high nickel lithium-ion battery ternary positive electrode material is obtained according to the single crystal or quasi-single crystal type ultra-high nickel lithium-ion battery ternary positive electrode material preparation method.

[0029] Application of single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode materials in lithium-ion batteries.

[0030] Compared with the prior art, the beneficial technical effects of the present invention are as follows: (1) The coating of the material surface with lithium phosphate in the present invention significantly improves its electrochemical stability, structural stability, thermal stability, and electronic and ion transport performance. First, the lithium phosphate coated on the surface of the material has excellent chemical stability and Li+ conductivity. As a protective layer, it reduces the direct contact between the high-nickel ternary material and the electrolyte, inhibits the side reaction of the electrolyte, and improves the electrochemical stability of the material. Second, the lithium phosphate coating layer can effectively stabilize the surface crystal structure of the ternary material during the charging and discharging process, alleviate the volume change of the material during the charging and discharging process, inhibit the generation of microcracks in the particles during the cycle, and improve the cycle performance of the material. Third, the lithium phosphate coating layer can increase the thermal decomposition temperature of the material and enhance the thermal stability of the battery, thereby improving its safety in use under high temperature environments. Fourth, the lithium phosphate coating layer can effectively inhibit the erosion of the material by HF decomposed by the electrolyte, thereby improving the cycle stability of the material. Fifth, lithium phosphate has good electronic and lithium ion transport properties, and the coating layer can ensure that the material has a high specific capacity while maintaining good cycle performance and thermal stability.

[0031] (2) During the coating process, urea phosphate is used as the solute and N-methylpyrrolidone NMP is used as the solvent and fully mixed to prepare an in-situ wet coating agent. Then the primary sintered product is fully mixed with the wet coating agent. The stirring process adopts a water bath heating method and undergoes two stirring processes with different parameters. By using the in-situ wet coating method and two-stage stirring, the additive is fully and evenly coated on the surface of the material. In the subsequent process, the NMP and moisture in the material are fully removed through processes such as suction filtration and two-stage pre-calcination drying to prepare the material with the best performance.

[0032] (3) The residual alkali content on the surface of the material has an absolute influence on the performance of the material. A high amount of residual alkali on the surface will cause the battery to form more side reaction products during the charge and discharge process, thereby increasing the internal resistance and irreversible capacity loss of the battery and reducing the cycle life. The presence of residual alkali on the surface will affect the electrochemical reaction of the battery, leading to problems such as reduced battery capacity and poor rate performance. The decomposition of Li2CO3 on the surface of the material under high voltage is one of the main reasons for battery bloating, which will bring hidden dangers in terms of safety. During the secondary sintering process, urea phosphate reacts in situ with the residual alkali LiOH and Li2CO3 on the surface of the material to neutralize the residual alkali on the surface, reduce the residual alkali content of the material, reduce the internal resistance of the battery, reduce the irreversible capacity loss of the material, improve the cycle stability of the battery, improve the electrochemical performance of the battery, increase the energy density and power density of the battery, reduce the decomposition of Li2CO3, and improve the safety performance of the battery. In this process, lithium phosphate is generated and coated on the surface of the material, repairing the damage to the surface of the material caused by the water washing process, and improving the problem of reduced electrochemical performance of the material caused by water washing.

[0033] (4) Since the lithium phosphate coating layer broadens the charge and discharge voltage window of the ternary positive electrode material, the charge cut-off voltage of the material is increased from 4.25V to 4.35V, thereby increasing its energy density, and successfully preparing a ternary positive electrode material suitable for charging and discharging under high voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The present invention is a flow chart of the single crystal or quasi-single crystal type ultra-high nickel lithium-ion battery ternary positive electrode material.

[0035] Figure 2 This is a SEM image of the uncoated single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material in Comparative Example 1.

[0036] Figure 3 This is a SEM image of the single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material coated in Example 1.

[0037] Figure 4 The XRD diagrams of the single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode materials in the coated Example 1 and the uncoated blank sample of Comparative Example 1 are shown.

[0038] Figure 5 This is a TEM image of the uncoated single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material in Comparative Example 1.

[0039] Figure 6 This is a TEM image of the single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material coated in Example 1.

[0040] Figure 7This is the EDS image of the uncoated single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material in Comparative Example 1.

[0041] Figure 8 This is the EDS image of the single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material coated in Example 1. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the present invention clearer, the device proposed by the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings adopt a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, please refer to the accompanying drawings. It should be noted that the structure, proportion, size, etc. illustrated by the accompanying drawings of this specification are only used to match the content disclosed in the specification, so that people familiar with this technology can understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no technical substantive significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effect that the present invention can produce and the purpose that can be achieved, should still fall within the scope of the technical content disclosed by the present invention.

[0043] Figure 1 The present invention is a flow chart of the single crystal or quasi-single crystal type ultra-high nickel lithium-ion battery ternary positive electrode material. Figure 2 This is a SEM image of the uncoated single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material in Comparative Example 1. Figure 3 This is a SEM image of the single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material coated in Example 1. Figure 4 The XRD diagrams of the single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode materials in the coated Example 1 and the uncoated blank sample of Comparative Example 1 are shown. Figure 5 This is a TEM image of the uncoated single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material in Comparative Example 1. Figure 6 This is a TEM image of the single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material coated in Example 1. Figure 7 This is the EDS image of the uncoated single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material in Comparative Example 1.

[0044] Figure 8 This is an EDS image of the single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material coated in Example 1. Figure 1-Figure 8 As shown, Figure 2 This shows that single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode materials have been successfully prepared and have a complete structure. Figure 3 It shows that the surface of the material shows a smooth surface structure and a complete coating layer. Figure 4 It shows that there is no obvious change in the XRD pattern before and after coating, indicating that the coating does not change the crystal structure of the matrix material. Figure 5 Indicates that the material structure has no coating layer. Figure 6 This shows that the material has an obvious coating layer. Figure 7 It shows that the material contains the elements nickel, cobalt, manganese, strontium, zirconium and yttrium; among them, nickel, cobalt and manganese come from precursors, and strontium, zirconium and yttrium come from metal oxides. Figure 8 The invention discloses a method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material and its application.

[0045] The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material comprises the following steps:

[0046] Step 1: Break up and mix the cobalt hydroxide nickel manganese ternary precursor, lithium source and metal oxide acting as columnar metal ions to obtain a premixed material. Sinter the premixed material once, sieve and disperse it with a 400-mesh screen, and then wash it with water to obtain a sintered product. The water ratio of the premixed material after the first sintering is 0.5:1 to 2:1, the washing time is 1 to 5 minutes, and the washing temperature is 0 to 15°C.

[0047] Step 2: Urea phosphate and N-methylpyrrolidone NMP are fully mixed to prepare an in-situ wet coating agent, and the primary sintered product is mixed with the in-situ wet coating agent evenly, and then filtered, pre-calcined and dried, and sieved to obtain a pre-calcined product. The pre-calcined product is secondary sintered, and secondary sieved and dispersed to obtain a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material.

[0048] The structural formula of the material is [Li x Co a Ni b Mn 1-a-b ]O2·L i M y O z ; Wherein, 1.0<x<1.09, 0.04<a<1, 0.04<b<1; M is a metal element within yttrium, zirconium, magnesium, strontium and M y O z It is one or more composite oxides having a valence composition, wherein 0<y<3, 0<z≤3, and 1.9<x+a+b<2.5.

[0049] The mass ratio of the total medium of the cobalt hydroxide nickel manganese ternary precursor, the lithium source and the metal oxide acting as the columnar metal ion: the polyurethane zirconium ball is 2:1 to 1:2.

[0050] In step 1: the molecular formula of the cobalt hydroxide nickel manganese ternary precursor is Co a Ni b Mn 1-a-b (OH)2. Among them, the particle size is D50: 2.5 ~ 5μm. The molecular formula of single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material is [Li x Co a Nib 1-a-b ]O2. Among them, 1.0<x<1.09.

[0051] In step 1: the molecular formula of the lithium source is one or more of LiOH·H2O, LiOH, Li2CO3, LiCl, LiNO3, and C2H3LiO2.

[0052] In step 1: the metal oxide is strontium oxide, nickel oxide, zinc oxide, manganese oxide, aluminum oxide, rubidium oxide, zirconium oxide, tungsten oxide, molybdenum oxide, magnesium oxide, niobium oxide, titanium oxide, lanthanum oxide, antimony oxide, yttrium oxide or more of the present embodiment.

[0053] Urea phosphate is introduced as an additive in this application, and the introduction of urea phosphate coating on the surface of the material significantly improves its electrochemical stability, structural stability, thermal stability, and electronic and ion transport properties. This allows the material to be charged and discharged at high voltage and also has good structural stability, cycle performance, rate performance and high specific capacity, improves the energy density of the material, and enables the single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material to still have good electrochemical properties at a voltage of 4.35V.

[0054] Secondly, the residual alkali content on the surface is to detect the content of LiOH and Li2CO3 in the primary sintering product. Urea phosphate can reduce the residual alkali content on the surface of the material. Urea phosphate reacts in situ with the residual alkali LiOH and Li2CO3 on the surface of the material, captures the Li+ therein, neutralizes the residual alkali on the surface, reduces the residual alkali content of the material, reduces the internal resistance of the battery, reduces the irreversible capacity loss of the material, and increases the cycle life, thereby improving the cycle stability, rate performance, energy density and power density of the battery.

[0055] This process also generates lithium phosphate, which is coated on the surface of the material, repairing the damage to the material surface caused by the water washing process, and solving the problem of the material's electrochemical performance degradation caused by the water washing process. In addition, urea phosphate is coated on the surface of the material using an in-situ wet coating method, and a two-stage water bath heating and stirring method is used as well as pre-burning and drying the NMP and water in the material to prepare a more uniform and complete coating layer, laying the foundation for the high performance of the material.

[0056] The single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material is prepared by using the single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material preparation method.

[0057] Application of single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode materials in lithium-ion batteries.

[0058] Embodiment 1:

[0059] The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material comprises the following steps:

[0060] In step 1, the lithium source molecular formula is LiOH·H2O, and the metal oxides are strontium oxide, zirconium oxide and yttrium oxide. 0.05 Ni 0.90 Mn 0.05 50 g of the cobalt nickel manganese hydroxide ternary precursor of (OH)2, the molar ratio of the lithium source molecule to the cobalt nickel manganese hydroxide ternary precursor is 1.04:1, and they are mixed evenly by a dry method.

[0061] Add 1000PPm strontium oxide, 1000PPm zirconium oxide and 1000PPm yttrium oxide and mix again. Use polyurethane zirconium balls as the mixing medium. During the mixing process, the mass ratio of large balls to small balls in the polyurethane zirconium balls is 1:1. The mixing and dispersion time is 3h and the rotation speed is 180rpm.

[0062] The primary sintering in step 1 includes the following processes:

[0063] The premixed materials are loaded into the sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 600℃, the heating rate is 3℃ / min, and the temperature is kept for 4h;

[0064] The temperature in the sintering furnace was raised to 800°C at a heating rate of 3°C / min and kept at this temperature for 10 h, and then cooled to room temperature along with the furnace.

[0065] The material was taken out, sieved and dispersed using a 400-mesh screen, and then washed with water to obtain a primary sintered product. The water ratio of the primary sintered product to the premixed material was 1:1, the washing time was 3 minutes, and the washing temperature was 10°C.

[0066] In step 2, the contents of LiOH and Li2CO3 in the primary sintering product are detected, that is, the surface residual alkali content; the primary sintering product and the in-situ wet coating agent are evenly mixed, and the molar ratio of the added content of urea phosphate to the surface residual alkali in the in-situ wet coating agent is 1:1; urea phosphate is added to N-methylpyrrolidone NMP solution to prepare an in-situ wet coating agent with a urea phosphate mass percentage of 2wt%.

[0067] In step 2: the primary sintered product and the in-situ wet coating agent are mixed uniformly by using a water bath heating method through two stirring processes with different parameters;

[0068] The first stage stirring speed is 300r / min, stirring time is 2h. The second stage stirring speed is 1000r / min, stirring time is 10h, temperature is 50℃.

[0069] After stirring, suction filtration is performed to remove the NMP solution, and then pre-calcination and drying are performed, and the pre-calcination product is obtained by sieving. Oxygen is introduced into the pre-calcination and drying process, and the process is divided into two stages:

[0070] The first stage of sintering: the temperature is 90℃ and the sintering time is 180min;

[0071] The second stage of sintering: the temperature is 120℃ and the sintering time is 540min.

[0072] The secondary sintering in step 2 includes the following processes:

[0073] The pre-burned product is put into a sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 500°C, the heating rate is 3°C / min, and it is kept warm for 6 hours; it is cooled to room temperature with the furnace.

[0074] During the sintering process, the materials are heated evenly to obtain single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material products. The finished products are tested for button battery charge and discharge cycles at a voltage window of 2.8 to 4.35V.

[0075] Embodiment 2:

[0076] The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material comprises the following steps:

[0077] In step 1, the lithium source molecular formula is LiOH·H2O, and the metal oxides are strontium oxide, zirconium oxide and yttrium oxide. 0.05 Ni 0.90 Mn 0.05 50 g of the cobalt nickel manganese hydroxide ternary precursor of (OH)2, the molar ratio of the lithium source molecule to the cobalt nickel manganese hydroxide ternary precursor is 1.04:1, and they are mixed evenly by a dry method.

[0078] Add 1000PPm strontium oxide, 1000PPm zirconium oxide and 1000PPm yttrium oxide and mix again. Use polyurethane zirconium balls as the mixing medium. During the mixing process, the mass ratio of large balls to small balls in the polyurethane zirconium balls is 1:1. The mixing and dispersion time is 3h and the rotation speed is 180rpm.

[0079] The primary sintering in step 1 includes the following processes:

[0080] The premixed materials are loaded into the sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 600℃, the heating rate is 3℃ / min, and the temperature is kept for 4h;

[0081] The temperature in the sintering furnace was raised to 800°C at a heating rate of 3°C / min and kept at this temperature for 10 h, and then cooled to room temperature along with the furnace.

[0082] The material was taken out, sieved and dispersed using a 400-mesh screen, and then washed with water to obtain a primary sintered product. The water ratio of the primary sintered product to the premixed material was 1:1, the washing time was 3 minutes, and the washing temperature was 10°C.

[0083] In step 2, the contents of LiOH and Li2CO3 in the primary sintering product are detected, that is, the surface residual alkali content; the primary sintering product and the in-situ wet coating agent are mixed evenly, and the molar ratio of the added content of urea phosphate to the surface residual alkali in the in-situ wet coating agent is 0.95:1; urea phosphate is added to N-methylpyrrolidone NMP solution to prepare an in-situ wet coating agent with a urea phosphate mass percentage of 2wt%.

[0084] In step 2: the primary sintered product and the in-situ wet coating agent are mixed uniformly by using a water bath heating method through two stirring processes with different parameters;

[0085] The first stage stirring speed is 300r / min, stirring time is 2h. The second stage stirring speed is 1000r / min, stirring time is 10h, temperature is 50℃.

[0086] After stirring, suction filtration is performed to remove the NMP solution, and then pre-calcination and drying are performed, and the pre-calcination product is obtained by sieving. Oxygen is introduced into the pre-calcination and drying process, and the process is divided into two stages:

[0087] The first stage of sintering: the temperature is 90℃ and the sintering time is 180min;

[0088] The second stage of sintering: the temperature is 120℃ and the sintering time is 540min.

[0089] The secondary sintering in step 2 includes the following processes:

[0090] The pre-burned product is put into a sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 500°C, the heating rate is 3°C / min, and it is kept warm for 6 hours; it is cooled to room temperature with the furnace.

[0091] During the sintering process, the materials are heated evenly to obtain single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material products. The finished products are tested for button battery charge and discharge cycles at a voltage window of 2.8 to 4.35V.

[0092] Embodiment 3:

[0093] The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material comprises the following steps:

[0094] In step 1, the lithium source molecular formula is LiOH·H2O, and the metal oxides are strontium oxide, zirconium oxide and yttrium oxide. 0.05 Ni 0.90 Mn 0.05 50 g of the cobalt nickel manganese hydroxide ternary precursor of (OH)2, the molar ratio of the lithium source molecule to the cobalt nickel manganese hydroxide ternary precursor is 1.04:1, and they are mixed evenly by a dry method.

[0095] Add 1000PPm strontium oxide, 1000PPm zirconium oxide and 1000PPm yttrium oxide and mix again. Use polyurethane zirconium balls as the mixing medium. During the mixing process, the mass ratio of large balls to small balls in the polyurethane zirconium balls is 1:1. The mixing and dispersion time is 3h and the rotation speed is 180rpm.

[0096] The primary sintering in step 1 includes the following processes:

[0097] The premixed materials are loaded into the sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 600℃, the heating rate is 3℃ / min, and the temperature is kept for 4h;

[0098] The temperature in the sintering furnace was raised to 800°C at a heating rate of 3°C / min and kept at this temperature for 10 h, and then cooled to room temperature along with the furnace.

[0099] The material was taken out, sieved and dispersed using a 400-mesh screen, and then washed with water to obtain a primary sintered product. The water ratio of the primary sintered product to the premixed material was 1:1, the washing time was 3 minutes, and the washing temperature was 10°C.

[0100] In step 2, the contents of LiOH and Li2CO3 in the primary sintering product are detected, that is, the surface residual alkali content; the primary sintering product and the in-situ wet coating agent are evenly mixed, and the molar ratio of the added content of urea phosphate to the surface residual alkali in the in-situ wet coating agent is 1.05:1; urea phosphate is added to N-methylpyrrolidone NMP solution to prepare an in-situ wet coating agent with a urea phosphate mass percentage of 2wt%.

[0101] In step 2: the primary sintered product and the in-situ wet coating agent are mixed uniformly by using a water bath heating method through two stirring processes with different parameters;

[0102] The first stage stirring speed is 300r / min, stirring time is 2h. The second stage stirring speed is 1000r / min, stirring time is 10h, temperature is 50℃.

[0103] After stirring, suction filtration is performed to remove the NMP solution, and then pre-calcination and drying are performed, and the pre-calcination product is obtained by sieving. Oxygen is introduced into the pre-calcination and drying process, and the process is divided into two stages:

[0104] The first stage of sintering: the temperature is 90℃ and the sintering time is 180min;

[0105] The second stage of sintering: the temperature is 120℃ and the sintering time is 540min.

[0106] The secondary sintering in step 2 includes the following processes:

[0107] The pre-burned product is put into a sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 500°C, the heating rate is 3°C / min, and it is kept warm for 6 hours; it is cooled to room temperature with the furnace.

[0108] During the sintering process, the materials are heated evenly to obtain single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material products. The finished products are tested for button battery charge and discharge cycles at a voltage window of 2.8 to 4.35V.

[0109] Embodiment 4:

[0110] The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material comprises the following steps:

[0111] In step 1, the lithium source molecular formula is LiOH·H2O, and the metal oxides are strontium oxide, zirconium oxide and yttrium oxide. 0.05 Ni 0.90 Mn 0.05 50 g of the cobalt nickel manganese hydroxide ternary precursor of (OH)2, the molar ratio of the lithium source molecule to the cobalt nickel manganese hydroxide ternary precursor is 1.04:1, and they are mixed evenly by a dry method.

[0112] Add 1000PPm strontium oxide, 1000PPm zirconium oxide and 1000PPm yttrium oxide and mix again. Use polyurethane zirconium balls as the mixing medium. During the mixing process, the mass ratio of large balls to small balls in the polyurethane zirconium balls is 1:1. The mixing and dispersion time is 3h and the rotation speed is 180rpm.

[0113] The primary sintering in step 1 includes the following processes:

[0114] The premixed materials are loaded into the sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 600℃, the heating rate is 3℃ / min, and the temperature is kept for 4h;

[0115] The temperature in the sintering furnace was raised to 800°C at a heating rate of 3°C / min and kept at this temperature for 10 h, and then cooled to room temperature along with the furnace.

[0116] The material was taken out, sieved and dispersed using a 400-mesh screen, and then washed with water to obtain a primary sintered product. The water ratio of the primary sintered product to the premixed material was 1:1, the washing time was 3 minutes, and the washing temperature was 10°C.

[0117] In step 2, the contents of LiOH and Li2CO3 in the primary sintering product are detected, that is, the surface residual alkali content; the primary sintering product and the in-situ wet coating agent are evenly mixed, and the molar ratio of the added content of urea phosphate to the surface residual alkali in the in-situ wet coating agent is 1:1; urea phosphate is added to N-methylpyrrolidone NMP solution to prepare an in-situ wet coating agent with a urea phosphate mass percentage of 2wt%.

[0118] In step 2: the primary sintered product and the in-situ wet coating agent are mixed uniformly by using a water bath heating method through two stirring processes with different parameters;

[0119] The first stage stirring speed is 300r / min, stirring time is 2h. The second stage stirring speed is 1000r / min, stirring time is 10h, temperature is 50℃.

[0120] After stirring, suction filtration is performed to remove the NMP solution, and then pre-calcination and drying are performed, and the pre-calcination product is obtained by sieving. Oxygen is introduced into the pre-calcination and drying process, and the process is divided into two stages:

[0121] The first stage of sintering: the temperature is 90℃ and the sintering time is 180min;

[0122] The second stage of sintering: the temperature is 120℃ and the sintering time is 540min.

[0123] The secondary sintering in step 2 includes the following processes:

[0124] The pre-burned product is put into a sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 500°C, the heating rate is 3°C / min, and it is kept warm for 6 hours; it is cooled to room temperature with the furnace.

[0125] During the sintering process, the materials are heated evenly to obtain single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material products. The finished products are tested for button battery charge and discharge cycles at a voltage window of 2.8 to 4.45V.

[0126] Embodiment 5:

[0127] The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material comprises the following steps:

[0128] In step 1, the lithium source molecular formula is LiOH·H2O, and the metal oxides are strontium oxide, zirconium oxide and yttrium oxide. 0.05 Ni 0.90 Mn 0.05 50 g of the cobalt nickel manganese hydroxide ternary precursor of (OH)2, the molar ratio of the lithium source molecule to the cobalt nickel manganese hydroxide ternary precursor is 1.04:1, and they are mixed evenly by a dry method.

[0129] Add 1000PPm strontium oxide, 1000PPm zirconium oxide and 1000PPm yttrium oxide and mix again. Use polyurethane zirconium balls as the mixing medium. During the mixing process, the mass ratio of large balls to small balls in the polyurethane zirconium balls is 1:1. The mixing and dispersion time is 3h and the rotation speed is 180rpm.

[0130] The primary sintering in step 1 includes the following processes:

[0131] The premixed materials are loaded into the sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 600℃, the heating rate is 3℃ / min, and the temperature is kept for 4h;

[0132] The temperature in the sintering furnace was raised to 800°C at a heating rate of 3°C / min and kept at this temperature for 10 h, and then cooled to room temperature along with the furnace.

[0133] The material was taken out, sieved and dispersed using a 400-mesh screen, and then washed with water to obtain a primary sintered product. The water ratio of the primary sintered product to the premixed material was 1:1, the washing time was 3 minutes, and the washing temperature was 10°C.

[0134] In step 2, the contents of LiOH and Li2CO3 in the primary sintering product are detected, that is, the surface residual alkali content; the primary sintering product and the in-situ wet coating agent are evenly mixed, and the molar ratio of the added content of urea phosphate to the surface residual alkali in the in-situ wet coating agent is 1:1; urea phosphate is added to N-methylpyrrolidone NMP solution to prepare an in-situ wet coating agent with a urea phosphate mass percentage of 2wt%.

[0135] In step 2: the primary sintered product and the in-situ wet coating agent are mixed uniformly by using a water bath heating method through two stirring processes with different parameters;

[0136] The first stage stirring speed is 300r / min, stirring time is 2h. The second stage stirring speed is 1000r / min, stirring time is 10h, temperature is 50℃.

[0137] After stirring, suction filtration is performed to remove the NMP solution, and then pre-calcination and drying are performed, and the pre-calcination product is obtained by sieving. Oxygen is introduced into the pre-calcination and drying process, and the process is divided into two stages:

[0138] The first stage of sintering: the temperature is 90℃ and the sintering time is 180min;

[0139] The second stage of sintering: the temperature is 120℃ and the sintering time is 540min.

[0140] The secondary sintering in step 2 includes the following processes:

[0141] The pre-burned product is put into a sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 500°C, the heating rate is 3°C / min, and it is kept warm for 6 hours; it is cooled to room temperature with the furnace.

[0142] During the sintering process, the materials are heated evenly to obtain single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material products. The finished products are tested for button battery charge and discharge cycles at a voltage window of 2.8 to 4.25V.

[0143] Embodiment 6:

[0144] The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material comprises the following steps:

[0145] In step 1, the lithium source molecular formula is LiOH·H2O, and the metal oxides are strontium oxide, zirconium oxide and yttrium oxide. 0.05 Ni 0.90 Mn 0.05 50 g of the cobalt nickel manganese hydroxide ternary precursor of (OH)2, the molar ratio of the lithium source molecule to the cobalt nickel manganese hydroxide ternary precursor is 1.04:1, and they are mixed evenly by a dry method.

[0146] Add 1000PPm strontium oxide, 1000PPm zirconium oxide and 1000PPm yttrium oxide and mix again. Use polyurethane zirconium balls as the mixing medium. During the mixing process, the mass ratio of large balls to small balls in the polyurethane zirconium balls is 1:1. The mixing and dispersion time is 3h and the rotation speed is 180rpm.

[0147] The primary sintering in step 1 includes the following processes:

[0148] The premixed materials are loaded into the sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 600℃, the heating rate is 3℃ / min, and the temperature is kept for 4h;

[0149] The temperature in the sintering furnace was raised to 800°C at a heating rate of 3°C / min and kept at this temperature for 10 h, and then cooled to room temperature along with the furnace.

[0150] The material was taken out, sieved and dispersed using a 400-mesh screen, and then washed with water to obtain a primary sintered product. The water ratio of the primary sintered product to the premixed material was 1:1, the washing time was 3 minutes, and the washing temperature was 10°C.

[0151] In step 2, the contents of LiOH and Li2CO3 in the primary sintering product are detected, that is, the surface residual alkali content; the primary sintering product and the in-situ wet coating agent are evenly mixed, and the molar ratio of the added content of urea phosphate to the surface residual alkali in the in-situ wet coating agent is 1:1; urea phosphate is added to N-methylpyrrolidone NMP solution to prepare an in-situ wet coating agent with a urea phosphate mass percentage of 2wt%.

[0152] In step 2: the primary sintered product and the in-situ wet coating agent are mixed uniformly by using a water bath heating method through two stirring processes with different parameters;

[0153] The first stage stirring speed is 200r / min, stirring time is 2h. The second stage stirring speed is 800r / min, stirring time is 10h, temperature is 50℃.

[0154] After stirring, suction filtration is performed to remove the NMP solution, and then pre-calcination and drying are performed, and the pre-calcination product is obtained by sieving. Oxygen is introduced into the pre-calcination and drying process, and the process is divided into two stages:

[0155] The first stage of sintering: the temperature is 90℃ and the sintering time is 180min;

[0156] The second stage of sintering: the temperature is 120℃ and the sintering time is 540min.

[0157] The secondary sintering in step 2 includes the following processes:

[0158] The pre-burned product is put into a sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 500°C, the heating rate is 3°C / min, and it is kept warm for 6 hours; it is cooled to room temperature with the furnace.

[0159] During the sintering process, the materials are heated evenly to obtain single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material products. The finished products are tested for button battery charge and discharge cycles at a voltage window of 2.8 to 4.35V.

[0160] Embodiment 7:

[0161] The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material comprises the following steps:

[0162] In step 1, the lithium source molecular formula is LiOH·H2O, and the metal oxides are strontium oxide, zirconium oxide and yttrium oxide. 0.05 Ni 0.90 Mn 0.0550 g of the cobalt nickel manganese hydroxide ternary precursor of (OH)2, the molar ratio of the lithium source molecule to the cobalt nickel manganese hydroxide ternary precursor is 1.04:1, and they are mixed evenly by a dry method.

[0163] Add 1000PPm strontium oxide, 1000PPm zirconium oxide and 1000PPm yttrium oxide and mix again. Use polyurethane zirconium balls as the mixing medium. During the mixing process, the mass ratio of large balls to small balls in the polyurethane zirconium balls is 1:1. The mixing and dispersion time is 3h and the rotation speed is 180rpm.

[0164] The primary sintering in step 1 includes the following processes:

[0165] The premixed materials are loaded into the sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 600℃, the heating rate is 3℃ / min, and the temperature is kept for 4h;

[0166] The temperature in the sintering furnace was raised to 800°C at a heating rate of 3°C / min and kept at this temperature for 10 h, and then cooled to room temperature along with the furnace.

[0167] The material was taken out, sieved and dispersed using a 400-mesh screen, and then washed with water to obtain a primary sintered product. The water ratio of the primary sintered product to the premixed material was 1:1, the washing time was 3 minutes, and the washing temperature was 10°C.

[0168] In step 2, the contents of LiOH and Li2CO3 in the primary sintering product are detected, that is, the surface residual alkali content; the primary sintering product and the in-situ wet coating agent are evenly mixed, and the molar ratio of the added content of urea phosphate to the surface residual alkali in the in-situ wet coating agent is 1:1; urea phosphate is added to N-methylpyrrolidone NMP solution to prepare an in-situ wet coating agent with a urea phosphate mass percentage of 2wt%.

[0169] In step 2: the primary sintered product and the in-situ wet coating agent are mixed uniformly by using a water bath heating method through two stirring processes with different parameters;

[0170] The first stage stirring speed is 400r / min, stirring time is 2h. The second stage stirring speed is 1200r / min, stirring time is 10h, temperature is 50℃.

[0171] After stirring, suction filtration is performed to remove the NMP solution, and then pre-calcination and drying are performed, and the pre-calcination product is obtained by sieving. Oxygen is introduced into the pre-calcination and drying process, and the process is divided into two stages:

[0172] The first stage of sintering: the temperature is 90℃ and the sintering time is 180min;

[0173] The second stage of sintering: the temperature is 120℃ and the sintering time is 540min.

[0174] The secondary sintering in step 2 includes the following processes:

[0175] The pre-burned product is put into a sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 500°C, the heating rate is 3°C / min, and it is kept warm for 6 hours; it is cooled to room temperature with the furnace.

[0176] During the sintering process, the materials are heated evenly to obtain single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material products. The finished products are tested for button battery charge and discharge cycles at a voltage window of 2.8 to 4.35V.

[0177] Embodiment 8:

[0178] The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material comprises the following steps:

[0179] In step 1, the lithium source molecular formula is LiOH·H2O, and the metal oxides are strontium oxide, zirconium oxide and yttrium oxide. 0.05 Ni 0.90 Mn 0.05 50 g of the cobalt nickel manganese hydroxide ternary precursor of (OH)2, the molar ratio of the lithium source molecule to the cobalt nickel manganese hydroxide ternary precursor is 1.04:1, and they are mixed evenly by a dry method.

[0180] Add 1000PPm strontium oxide, 1000PPm zirconium oxide and 1000PPm yttrium oxide and mix again. Use polyurethane zirconium balls as the mixing medium. During the mixing process, the mass ratio of large balls to small balls in the polyurethane zirconium balls is 1:1. The mixing and dispersion time is 3h and the rotation speed is 180rpm.

[0181] The primary sintering in step 1 includes the following processes:

[0182] The premixed materials are loaded into the sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 600℃, the heating rate is 3℃ / min, and the temperature is kept for 4h;

[0183] The temperature in the sintering furnace was raised to 800°C at a heating rate of 3°C / min and kept at this temperature for 10 h, and then cooled to room temperature along with the furnace.

[0184] The material was taken out, sieved and dispersed using a 400-mesh screen, and then washed with water to obtain a primary sintered product. The water ratio of the primary sintered product to the premixed material was 1:1, the washing time was 3 minutes, and the washing temperature was 10°C.

[0185] In step 2, the contents of LiOH and Li2CO3 in the primary sintering product are detected, that is, the surface residual alkali content; the primary sintering product and the in-situ wet coating agent are evenly mixed, and the molar ratio of the added content of urea phosphate to the surface residual alkali in the in-situ wet coating agent is 1:1; urea phosphate is added to N-methylpyrrolidone NMP solution to prepare an in-situ wet coating agent with a urea phosphate mass percentage of 2wt%.

[0186] In step 2: the primary sintered product and the in-situ wet coating agent are mixed uniformly by using a water bath heating method through two stirring processes with different parameters;

[0187] The first stage stirring speed is 300r / min, stirring time is 1h. The second stage stirring speed is 1000r / min, stirring time is 8h, and the temperature is 50℃.

[0188] After stirring, suction filtration is performed to remove the NMP solution, and then pre-calcination and drying are performed, and the pre-calcination product is obtained by sieving. Oxygen is introduced into the pre-calcination and drying process, and the process is divided into two stages:

[0189] The first stage of sintering: the temperature is 90℃ and the sintering time is 180min;

[0190] The second stage of sintering: the temperature is 120℃ and the sintering time is 540min.

[0191] The secondary sintering in step 2 includes the following processes:

[0192] The pre-burned product is put into a sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 500°C, the heating rate is 3°C / min, and it is kept warm for 6 hours; it is cooled to room temperature with the furnace.

[0193] During the sintering process, the materials are heated evenly to obtain single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material products. The finished products are tested for button battery charge and discharge cycles at a voltage window of 2.8 to 4.35V.

[0194] Embodiment 9:

[0195] The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material comprises the following steps:

[0196] In step 1, the lithium source molecular formula is LiOH·H2O, and the metal oxides are strontium oxide, zirconium oxide and yttrium oxide. 0.05 Ni 0.90 Mn 0.05 50 g of the cobalt nickel manganese hydroxide ternary precursor of (OH)2, the molar ratio of the lithium source molecule to the cobalt nickel manganese hydroxide ternary precursor is 1.04:1, and they are mixed evenly by a dry method.

[0197] Add 1000PPm strontium oxide, 1000PPm zirconium oxide and 1000PPm yttrium oxide and mix again. Use polyurethane zirconium balls as the mixing medium. During the mixing process, the mass ratio of large balls to small balls in the polyurethane zirconium balls is 1:1. The mixing and dispersion time is 3h and the rotation speed is 180rpm.

[0198] The primary sintering in step 1 includes the following processes:

[0199] The premixed materials are loaded into the sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 600℃, the heating rate is 3℃ / min, and the temperature is kept for 4h;

[0200] The temperature in the sintering furnace was raised to 800°C at a heating rate of 3°C / min and kept at this temperature for 10 h, and then cooled to room temperature along with the furnace.

[0201] The material was taken out, sieved and dispersed using a 400-mesh screen, and then washed with water to obtain a primary sintered product. The water ratio of the primary sintered product to the premixed material was 1:1, the washing time was 3 minutes, and the washing temperature was 10°C.

[0202] In step 2, the contents of LiOH and Li2CO3 in the primary sintering product are detected, that is, the surface residual alkali content; the primary sintering product and the in-situ wet coating agent are evenly mixed, and the molar ratio of the added content of urea phosphate to the surface residual alkali in the in-situ wet coating agent is 1:1; urea phosphate is added to N-methylpyrrolidone NMP solution to prepare an in-situ wet coating agent with a urea phosphate mass percentage of 2wt%.

[0203] In step 2: the primary sintered product and the in-situ wet coating agent are mixed uniformly by using a water bath heating method through two stirring processes with different parameters;

[0204] The first stage stirring speed is 300r / min, stirring time is 3h. The second stage stirring speed is 1000r / min, stirring time is 12h, temperature is 50℃.

[0205] After stirring, suction filtration is performed to remove the NMP solution, and then pre-calcination and drying are performed, and the pre-calcination product is obtained by sieving. Oxygen is introduced into the pre-calcination and drying process, and the process is divided into two stages:

[0206] The first stage of sintering: the temperature is 90℃ and the sintering time is 180min;

[0207] The second stage of sintering: the temperature is 120℃ and the sintering time is 540min.

[0208] The secondary sintering in step 2 includes the following processes:

[0209] The pre-burned product is put into a sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 500°C, the heating rate is 3°C / min, and it is kept warm for 6 hours; it is cooled to room temperature with the furnace.

[0210] During the sintering process, the materials are heated evenly to obtain single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material products. The finished products are tested for button battery charge and discharge cycles at a voltage window of 2.8 to 4.35V.

[0211] Embodiment 10:

[0212] The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material comprises the following steps:

[0213] In step 1, the lithium source molecular formula is LiOH·H2O, and the metal oxides are strontium oxide, zirconium oxide and yttrium oxide. 0.05 Ni 0.90 Mn 0.05 50 g of the cobalt nickel manganese hydroxide ternary precursor of (OH)2, the molar ratio of the lithium source molecule to the cobalt nickel manganese hydroxide ternary precursor is 1.04:1, and they are mixed evenly by a dry method.

[0214] Add 1000PPm strontium oxide, 1000PPm zirconium oxide and 1000PPm yttrium oxide and mix again. Use polyurethane zirconium balls as the mixing medium. During the mixing process, the mass ratio of large balls to small balls in the polyurethane zirconium balls is 1:1. The mixing and dispersion time is 3h and the rotation speed is 180rpm.

[0215] The primary sintering in step 1 includes the following processes:

[0216] The premixed materials are loaded into the sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 600℃, the heating rate is 3℃ / min, and the temperature is kept for 4h;

[0217] The temperature in the sintering furnace was raised to 800°C at a heating rate of 3°C / min and kept at this temperature for 10 h, and then cooled to room temperature along with the furnace.

[0218] The material was taken out, sieved and dispersed using a 400-mesh screen, and then washed with water to obtain a primary sintered product. The water ratio of the primary sintered product to the premixed material was 1:1, the washing time was 3 minutes, and the washing temperature was 10°C.

[0219] In step 2, the contents of LiOH and Li2CO3 in the primary sintering product are detected, that is, the surface residual alkali content; the primary sintering product and the in-situ wet coating agent are evenly mixed, and the molar ratio of the added content of urea phosphate to the surface residual alkali in the in-situ wet coating agent is 1:1; urea phosphate is added to N-methylpyrrolidone NMP solution to prepare an in-situ wet coating agent with a urea phosphate mass percentage of 2wt%.

[0220] In step 2: the primary sintered product and the in-situ wet coating agent are mixed uniformly by using a water bath heating method through two stirring processes with different parameters;

[0221] The first stage stirring speed is 300r / min, stirring time is 2h. The second stage stirring speed is 1000r / min, stirring time is 10h, temperature is 30℃.

[0222] After stirring, suction filtration is performed to remove the NMP solution, and then pre-calcination and drying are performed, and the pre-calcination product is obtained by sieving. Oxygen is introduced into the pre-calcination and drying process, and the process is divided into two stages:

[0223] The first stage of sintering: the temperature is 90℃ and the sintering time is 180min;

[0224] The second stage of sintering: the temperature is 120℃ and the sintering time is 540min.

[0225] The secondary sintering in step 2 includes the following processes:

[0226] The pre-burned product is put into a sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 500°C, the heating rate is 3°C / min, and it is kept warm for 6 hours; it is cooled to room temperature with the furnace.

[0227] During the sintering process, the materials are heated evenly to obtain single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material products. The finished products are tested for button battery charge and discharge cycles at a voltage window of 2.8 to 4.35V.

[0228] Embodiment 11:

[0229] The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material comprises the following steps:

[0230] In step 1, the lithium source molecular formula is LiOH·H2O, and the metal oxides are strontium oxide, zirconium oxide and yttrium oxide. 0.05 Ni 0.90 Mn 0.05 50 g of the cobalt nickel manganese hydroxide ternary precursor of (OH)2, the molar ratio of the lithium source molecule to the cobalt nickel manganese hydroxide ternary precursor is 1.04:1, and they are mixed evenly by a dry method.

[0231] Add 1000PPm strontium oxide, 1000PPm zirconium oxide and 1000PPm yttrium oxide and mix again. Use polyurethane zirconium balls as the mixing medium. During the mixing process, the mass ratio of large balls to small balls in the polyurethane zirconium balls is 1:1. The mixing and dispersion time is 3h and the rotation speed is 180rpm.

[0232] The primary sintering in step 1 includes the following processes:

[0233] The premixed materials are loaded into the sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 600℃, the heating rate is 3℃ / min, and the temperature is kept for 4h;

[0234] The temperature in the sintering furnace was raised to 800°C at a heating rate of 3°C / min and kept at this temperature for 10 h, and then cooled to room temperature along with the furnace.

[0235] The material was taken out, sieved and dispersed using a 400-mesh screen, and then washed with water to obtain a primary sintered product. The water ratio of the primary sintered product to the premixed material was 1:1, the washing time was 3 minutes, and the washing temperature was 10°C.

[0236] In step 2, the contents of LiOH and Li2CO3 in the primary sintering product are detected, that is, the surface residual alkali content; the primary sintering product and the in-situ wet coating agent are evenly mixed, and the molar ratio of the added content of urea phosphate to the surface residual alkali in the in-situ wet coating agent is 1:1; urea phosphate is added to N-methylpyrrolidone NMP solution to prepare an in-situ wet coating agent with a urea phosphate mass percentage of 2wt%.

[0237] In step 2: the primary sintered product and the in-situ wet coating agent are mixed uniformly by using a water bath heating method through two stirring processes with different parameters;

[0238] The first stage stirring speed is 300r / min, stirring time is 2h. The second stage stirring speed is 1000r / min, stirring time is 10h, temperature is 70℃.

[0239] After stirring, suction filtration is performed to remove the NMP solution, and then pre-calcination and drying are performed, and the pre-calcination product is obtained by sieving. Oxygen is introduced into the pre-calcination and drying process, and the process is divided into two stages:

[0240] The first stage of sintering: the temperature is 90℃ and the sintering time is 180min;

[0241] The second stage of sintering: the temperature is 120℃ and the sintering time is 540min.

[0242] The secondary sintering in step 2 includes the following processes:

[0243] The pre-burned product is put into a sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 500°C, the heating rate is 3°C / min, and it is kept warm for 6 hours; it is cooled to room temperature with the furnace.

[0244] During the sintering process, the materials are heated evenly to obtain single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material products. The finished products are tested for button battery charge and discharge cycles at a voltage window of 2.8 to 4.35V.

[0245] Comparative Example 1:

[0246] The molecular formula of the lithium source is LiOH·H2O, and the metal oxides are strontium oxide, zirconium oxide and yttrium oxide. 0.05 Ni 0.90 Mn 0.05 50 g of the cobalt nickel manganese hydroxide ternary precursor of (OH)2, the molar ratio of the lithium source molecule to the cobalt nickel manganese hydroxide ternary precursor is 1.04:1, and they are mixed evenly by a dry method.

[0247] Add 1000PPm strontium oxide, 1000PPm zirconium oxide and 1000PPm yttrium oxide and mix again. Use polyurethane zirconium balls as the mixing medium. During the mixing process, the mass ratio of large balls to small balls in the polyurethane zirconium balls is 1:1. The mixing and dispersion time is 3h and the rotation speed is 180rpm.

[0248] The primary sintering in step 1 includes the following processes:

[0249] The premixed materials are loaded into the sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 600℃, the heating rate is 3℃ / min, and the temperature is kept for 4h;

[0250] The temperature in the sintering furnace was raised to 800°C at a heating rate of 3°C / min and kept at this temperature for 10 h, and then cooled to room temperature along with the furnace.

[0251] The material was taken out, sieved and dispersed using a 400-mesh screen, and then washed with water to obtain a primary sintered product. The water ratio of the primary sintered product to the premixed material was 1:1, the washing time was 3 minutes, and the washing temperature was 10°C.

[0252] After drying, the finished product is subjected to a charge and discharge cycle test of a button cell at a voltage window of 2.8 to 4.35 V.

[0253] The materials prepared in the above embodiments and comparative examples were used as positive electrode materials to make button-type half-cells. The assembly order was negative electrode shell, lithium sheet, electrolyte LiPF6, diaphragm sheet, ultra-high nickel ternary positive electrode material, gasket, spring and positive electrode shell. Charge and discharge tests were performed. The above materials were also tested for residual alkali content, SEM test, EDS test, TEM test and XRD test. Table 1 shows the test of button-type half-cell performance:

[0254]

[0255]

[0256] Table 1

[0257] In order to further illustrate that the single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material prepared in this application has relatively high energy density and cycle stability, an analysis will be conducted in conjunction with specific drawings.

[0258] In Example 1, the specific capacity of the positive electrode material prepared under the optimal conditions reached 229.88 mAh / g, and the capacity retention rate reached 91% after 100 cycles at 1C, showing the characteristics of high specific capacity and high structural stability in the high voltage test window.

[0259] Example 2 and Example 3 adjust the added content of urea phosphate, the decomposition product of urea phosphate reacts with the residual alkali, and forms a coating layer on the surface of the material, and the added content of urea phosphate directly affects the amount of residual alkali in the positive electrode material. In Example 2, the amount of urea phosphate added is too little, and urea phosphate can react in situ with the residual alkali on the surface of the material, and capture the lithium ions in LiOH and Li2CO3. Urea phosphate is too little, resulting in a large amount of residual alkali remaining on the surface of the material, and the residual alkali content in the material is too high, so that the material increases the irreversible capacity loss, and the battery capacity decays faster. The excessive residual alkali will also cause the surface structure of the material to be unstable, and the cycle and rate performance will decrease, and the discharge capacity will decrease at high current density. In Example 3, the added content of urea phosphate is too high, resulting in the formation of an overly thick coating layer on the surface of the material, and the coating amount is too much, resulting in the active sites on the surface of the material being over-covered, affecting the electrochemical reaction activity of the material, thereby reducing the cycle stability and capacity, and the overly thick coating will also hinder the transmission of electrons and ions, resulting in a decrease in rate performance.

[0260] Example 4 adjusts the charge and discharge voltage window of the button half-cell. When the charge cut-off voltage is too high, the material is prone to structural degradation, such as the order of the layered structure deteriorates and the cation mixing phenomenon intensifies. This structural change will cause the battery's cycle performance and capacity retention rate to decrease significantly. And the battery's ohmic internal resistance, SEI film impedance, and charge transfer impedance will increase significantly. The increase in these impedances will hinder the transmission of lithium ions and the transfer process of electrons, resulting in a decrease in the battery's rate performance and discharge capacity.

[0261] Example 5 was tested under a normal charge and discharge voltage window. Compared with Example 1, the specific capacity of the material was reduced, so the energy density was lower.

[0262] The stirring speed, stirring time and stirring temperature during the two-stage stirring of the primary sintered product and the in-situ wet coating agent were adjusted in Example 6, Example 7, Example 8, Example 9, Example 10 and Example 11. When the stirring speed is slow, the stirring time is short and the stirring temperature is low, the stirring is insufficient, which will lead to uneven or incomplete material coating. If the stirring temperature is too high, the volatilization of NMP will be accelerated. If the stirring time is too long, not only NMP will volatilize, but also water will be absorbed, affecting the material properties.

[0263] Comparative Example 1 is a blank sample without the addition of urea phosphate. Since the material has no coating layer, the electrochemical properties such as specific capacity, cycle, and rate at high voltage are poor, and the energy density is low.

[0264] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0265] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material, characterized in that: The steps include: Step 1: breaking up and uniformly mixing the cobalt hydroxide nickel manganese ternary precursor, the lithium source and the metal oxide acting as the columnar metal ion to obtain a premixed material; sintering the premixed material once, sieving and dispersing it, and washing it with water to obtain a primary sintered product; Step 2: Urea phosphate and N-methylpyrrolidone NMP are fully mixed to prepare an in-situ wet coating agent, and the primary sintering product and the in-situ wet coating agent are evenly mixed, and then filtered, pre-calcined and dried, and sieved to obtain a pre-calcined product; The pre-sintered product is subjected to secondary sintering and secondary screening and dispersion to obtain a single crystal or quasi-single crystal type ultra-high nickel lithium-ion battery ternary positive electrode material.

2. The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material according to claim 1, characterized in that: In step 1: the molecular formula of the cobalt hydroxide nickel manganese ternary precursor is Co a Ni b Mn 1-a-b (OH)2; wherein the particle size is D50: 2.5-5 μm; the molecular formula of the single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material is [Li x Co a Ni b Mn 1-a-b ]O2; wherein, 1.0<x<1.

09.

3. The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material according to claim 1, characterized in that: In the step 1: the molecular formula of the lithium source is one or more of LiOH·H2O, LiOH, Li2CO3, LiCl, LiNO3, and C2H3LiO2.

4. The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material according to claim 1, characterized in that: In step 1, the metal oxide is one or more of strontium oxide, nickel oxide, zinc oxide, manganese oxide, aluminum oxide, rubidium oxide, zirconium oxide, tungsten oxide, molybdenum oxide, magnesium oxide, niobium oxide, titanium oxide, lanthanum oxide, antimony oxide, and yttrium oxide.

5. The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material according to claim 1, characterized in that: The structural formula of the material is [Li x Co a Ni b Mn 1-a-b ]O2·L i M y O z ; Wherein, 1.0<x<1.09, 0.04<a<1, 0.04<b<1; M is a metal element within yttrium, zirconium, magnesium, strontium and M y O z It is one or more composite oxides having a valence composition, wherein 0<y<3, 0<z≤3, and 1.9<x+a+b<2.

5.

6. The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material according to claim 1, characterized in that: In the step 1, the molar ratio of the lithium source to the cobalt nickel manganese hydroxide ternary precursor is 1.00-1.09:1, the polyurethane zirconium ball is used as the mixing medium, the total medium of the cobalt nickel manganese hydroxide ternary precursor, the lithium source and the metal oxide acting as the columnar metal ion: the polyurethane zirconium ball has a mass ratio of 2:1-1:2; the mass ratio of the large ball to the small ball in the polyurethane zirconium ball is 2:1-1:2, the mixing time is 2-6 hours, and the mixing speed is 100-300 rpm.

7. The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material according to claim 1, characterized in that: In the step 1: the added content of the metal oxide is: 0 PPm<metal oxide≤5000 PPm.

8. The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material according to claim 1, characterized in that: The primary sintering in step 1 includes the following process: The premixed materials are loaded into the sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 400-600°C, the heating rate is 2-5°C / min, and the temperature is kept for 2-6 hours; The temperature in the sintering furnace is raised to 550-880°C at a rate of 2-5°C / min, and is kept warm for 5-15 hours, and then cooled to room temperature along with the furnace.

9. The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material according to claim 1, characterized in that: In the step 2: the contents of LiOH and Li2CO3 in the primary sintering product are detected, i.e., the residual alkali content on the surface; the molar ratio of the added urea phosphate content to the residual alkali on the surface in the in-situ wet coating agent is 1:0.5 to 1:1.5; urea phosphate is added to an N-methylpyrrolidone (NMP) solution to prepare an in-situ wet coating agent in which the mass percentage of urea phosphate is 2 wt%.

10. The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material according to claim 1, characterized in that: In the step 2: the primary sintered product and the in-situ wet coating agent are uniformly mixed by a water bath heating method through two stirring processes with different parameters; The stirring speed of the first stage is 200-1000 r / min, and the stirring time is 1-5 h; the stirring speed of the second stage is 500-1500 r / min, and the stirring time is 5-15 h, and the temperature is 0-300°C.

11. The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material according to claim 1, characterized in that: In the step 2: oxygen is introduced into the pre-calcination and drying process and the process is divided into two stages; The first stage of sintering: the temperature is 50-150℃, and the sintering time is 30-200min; The second stage of sintering: the temperature is 50-300°C and the sintering time is 500-1000min.

12. The method for preparing a single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material according to claim 1, characterized in that: The secondary sintering in step 2 includes the following process: The pre-burned product is put into a sagger, oxygen is filled into the sintering furnace, and the sagger is placed in the sintering furnace; the sintering temperature is 300-700°C, the heating rate is 2-5°C / min, and the heat is kept for 3-9 hours; and the furnace is cooled to room temperature.

13. Single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material, characterized in that: Obtained according to the preparation method according to any one of claims 1 to 11.

14. Use of the single crystal or quasi-single crystal ultra-high nickel lithium-ion battery ternary positive electrode material according to claim 13 in lithium-ion batteries.

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