High-nickel positive electrode material of lithium ion battery as well as preparation method and application of high-nickel positive electrode material

Abstract

The invention belongs to the technical field of lithium ion batteries, and relates to a high-nickel positive electrode material of a lithium ion battery as well as a preparation method and application thereof. The preparation method comprises the steps that raw materials are mixed and then subjected to at least two times of sintering and one time of coating treatment, the raw materials are subjected to three times of sintering, the coating treatment is carried out before the third time of sintering, the temperature of the first time of sintering is 700-900 DEG C, and the raw materials comprise a Li source, a metal A source and a nickel-manganese hydroxide precursor. The prepared high-nickel positive electrode material of the lithium ion battery has relatively good cycle performance and relatively high capacity, and meanwhile, the increase of impedance in the cycle process of the battery is relatively small.

Description

[0001] Related Applications

[0002] This application is a divisional application of the parent application with application number 202111662231.5, invention name “A high-nickel positive electrode material for lithium-ion batteries, preparation method and application” and application date December 31, 2021. Technical Field

[0003] The invention belongs to the technical field of lithium ion batteries and relates to a high-nickel positive electrode material for lithium ion batteries and a preparation method and application thereof. Background Art

[0004] The new energy market has undergone dramatic changes in 2019. The growing number of electric vehicles has led to an increasing demand for the energy density and cost-effectiveness of lithium-ion batteries. Among them, cobalt is a scarce resource and has a high price in the lithium-cobalt-nickel-manganese ternary positive electrode material. In order to improve the cost-effectiveness and pursue high energy density, the content of nickel or manganese elements is appropriately increased, thereby reducing the amount of cobalt. Among them, increasing the nickel content can provide a high-capacity battery, but the increase in nickel content makes the structure of the material unstable, the solution reacts with the electrolyte solution, and due to repeated charging and discharging, cracks are generated in the positive electrode material, which deteriorates the cycle life of the lithium-ion battery, increases the impedance, and reduces the capacity. Therefore, it is urgent to develop new materials or find new materials to replace the scarce resource cobalt or reduce the amount of cobalt in the material.

[0005] Chinese patent CN102280636A discloses a positive electrode active material, a preparation method thereof and a rechargeable lithium battery comprising the same. The positive electrode active material of the rechargeable lithium battery is prepared by a coprecipitation method to prepare a precursor, and then mixed with a lithium source for sintering. The material includes pores, the pores have an average diameter of about 10nm to about 60nm, and the porosity of the material is about 0.5% to about 20%. The material has good particle strength, thereby preventing or reducing the occurrence of crushing after extrusion. The material tends not to react with the electrolyte and exhibits good thermal stability, thereby providing a high-capacity rechargeable lithium battery. However, the chemical formula of the material is Li a Ni x Co y Mn z M k O 2 , where 0.45≤x≤0.65, 0.15≤y≤0.25, 0.15<z≤0.35. The cobalt content of this material is relatively high, the capacity is insufficient, and the cost performance cannot meet the requirements.

[0006] Chinese patent CN108123119A discloses a nickel-based active material for a lithium secondary battery, a preparation method thereof and a lithium secondary battery including a positive electrode containing the same. The patent reports that a nickel-based active material is obtained by first treating a mixture of a lithium precursor and a metal hydroxide at low temperature under an oxygen atmosphere and then heat treating it at high temperature. The material may include secondary particles, wherein the secondary particles include agglomerates of at least two plate-like primary particles, wherein at least a portion of the secondary particles has a structure in which the plate-like primary particles are radially arranged, and the porosity of the exterior of the secondary particles is greater than the porosity of the interior of the secondary particles. However, the patent does not specify what aspects of the problem have been improved.

[0007] Chinese patent CN1856890 discloses lithium composite oxide particles for lithium secondary battery positive electrode materials, lithium secondary battery positive electrodes using the particles, and lithium secondary batteries. The patent reports a lithium composite oxide particle for a lithium secondary battery electrode material that can enhance the low temperature load characteristics of the battery and can also enhance the coating properties when manufacturing the positive electrode. The material must meet the following conditions (A) and at least one of the following conditions (B) and (C) in the measurement according to the mercury penetration method. Condition (A): On the mercury penetration curve, the amount of mercury penetration is less than or equal to 0.02cm3 / g when the pressure increases from 50MPa to 150MPa. Condition (B): On the mercury penetration curve, the amount of mercury penetration is greater than or equal to 0.01cm3 / g when the pressure increases from 50MPa to 150MPa. Condition (C): The average pore radius is 10nm-100nm, and the pore size distribution curve has a main peak with a peak located at a pore radius of 0.5μm-50μm, and a sub-peak with a peak located at a pore radius of 80nm-300nm. This patent mainly solves the low temperature performance, but fails to take into account the high temperature performance.

[0008] Chinese patent CN104272520A discloses a non-aqueous electrolyte secondary battery and a method for manufacturing the same. The patent reports that a positive electrode mixed material layer constituting a positive electrode of the non-aqueous electrolyte secondary battery has a peak A of differential pore capacity in a pore size range of 0.05 μm to 2 μm and a peak B located at a position closer to the smaller pore size than the peak A in a pore size distribution curve measured by a mercury porosimeter. The pore size distribution curve has a minimum point C between the peak A and the peak B where the differential pore capacity becomes a minimum value. The differential pore capacity X of the peak A is A and the differential pore volume X of the peak B B The differential pore volume X of the one with the larger differential pore volume L , and the differential pore volume X at the minimum point C C The ratio (X C / X L) is above 0.6. This patent mainly reduces the gas generation and other problems of the battery by adding overcharge additives during the battery manufacturing process.

[0009] Chinese patent CN112993239A discloses a high-voltage resistant low-cobalt ternary positive electrode material and its preparation method. The positive electrode material is prepared from a precursor containing nickel, cobalt, and manganese, a lithium source, and an additive containing metal elements, wherein (Ni 0.5 Co 0.1 Mn 0.4 )(OH) 2 As a precursor, the positive electrode material is made through low temperature, medium-high temperature and high temperature. The morphology of the positive electrode material is relatively regular, the particle size is uniform, and the lithium-ion battery made of the material still has low internal resistance and excellent high-temperature cycle performance under high voltage. However, the capacity of the material is low and cannot meet the application requirements.

[0010] Chinese patent CN108963218A discloses a preparation method and application of a low-cobalt, high-nickel ternary lithium. The positive electrode material is prepared by mixing nickel nitrate, titanium nitrate and manganese nitrate in a molar ratio of 8.75:0.25:1 into an aqueous solution, spray drying to obtain a precursor, and then using a traction agent to induce titanium-cobalt exchange. The precursor, traction agent and lithium hydroxide are prepared into a suspension in a certain molar ratio, spray dried, and then calcined. This material greatly improves its thermal stability, cycle life, and safety while further reducing the cobalt content. However, the material is mainly made into a finished product through one sintering, and the sintering time is limited, which cannot provide sufficient time and kinetic energy. The structure of the material cannot be well synthesized, and the cycle performance and thermal stability cannot be guaranteed.

[0011] Chinese patent CN112811475A discloses a single crystal positive electrode material, a preparation method thereof and a lithium ion battery. The patent reports that large particles of a polycrystalline precursor are subjected to airflow pulverization to obtain a single crystal precursor, and then sintered after lithium addition to obtain the positive electrode material. The method is simple in process and reduces production costs compared to the wet method. The material is sintered only once to form a finished product, and the sintering time is limited, which cannot provide sufficient time and kinetic energy. The structure of the material cannot be well synthesized, and the cycle performance and thermal stability cannot be guaranteed.

[0012] Chinese patent CN112750999A discloses a positive electrode material and a preparation method thereof and a lithium-ion battery, wherein the positive electrode material comprises a high-nickel cobalt-free multinary positive electrode material intermediate and a cobalt-containing compound coated on the outer surface of the high-nickel cobalt-free multinary positive electrode material intermediate, and the content of the cobalt element in the cobalt compound is 0.5-5 mol% of the total molar number of nickel and manganese. The material prepared by the method has a stable structure, high energy density, good rate performance, high capacity retention rate, etc. However, the free lithium of the material is relatively high, and gelation may occur during the battery pulping process, affecting battery processing. Summary of the invention

[0013] With the decrease of cobalt content, especially cobalt-free materials, the structural stability of ternary materials deteriorates, which makes the capacity, rate and cycle performance of the materials unable to function normally. Therefore, different strategies are proposed according to different requirements. For those with high requirements for cycle and safety, high-temperature sintering is used to obtain large single crystal materials; for those with high rate requirements, low-temperature sintering is used to obtain secondary particles with very small primary particles. However, such a strategy will always have certain shortcomings in the actual use of the battery.

[0014] The technical problem to be solved by the present invention is: the cobalt-free positive electrode materials in the prior art have high rate performance, and the problem that high capacity, long cycle and low DC internal resistance cannot be taken into account at the same time. The present invention provides a high-nickel positive electrode material for lithium-ion batteries and a preparation method thereof. The present invention prepares a high-nickel positive electrode material for lithium-ion batteries by adding modifying elements and at least two sintering and one coating treatment. The positive electrode material has a porous structure, which provides more paths for the migration of lithium ions and the paths are shorter, so that the lithium-ion battery not only has a higher capacity, but also has good rate performance; the lithium-ion battery also has good structural stability, and during the charging and discharging process of the lithium-ion battery, the capacity decay is reduced, the cycle performance is good, and the increase in DC internal resistance is small; the present invention also provides a positive electrode and a lithium-ion battery containing the above-mentioned lithium-ion positive electrode material; the present invention also provides the application of the above-mentioned lithium-ion battery high-nickel positive electrode material or lithium-ion battery positive electrode or lithium-ion battery in the field of digital batteries, power batteries or energy storage batteries.

[0015] To this end, the present invention provides the following first set of technical solutions.

[0016] The present invention provides a high-nickel positive electrode material for lithium-ion batteries. The high-nickel positive electrode material has a porous structure, and its chemical formula 1 is Li 1+a Ni b Mn c A d O 2 Elements of the composition shown, wherein: 0.01≤a≤0.24, 0.79<b≤0.96, 0.01<c≤0.20, 0<d≤0.06; A is selected from any one or two or more of Mn, Co, Al, Zr, Y, Rb, Cs, W, Ce, Mo, Ba, Ti, Mg, Ta, Nb, Ca, V, Sc, Sr and B elements, or selected from phosphorus-containing compounds containing at least one element of Ti, Al, Mg, Zr, La and Li elements.

[0017] Preferably, when measured by nitrogen adsorption method, the BJH pore size distribution curve has a single peak or multi-peak pore size distribution in the pore size range of 1.5-20 nm, and the total pore volume of the high nickel positive electrode material at a single point adsorption in the pore size range of 1.5-20 nm is within 0.01 cm 3 / g, preferably within 0.007cm 3 / g or less.

[0018] Preferably, in the powder X-ray diffraction spectrum of the positive electrode material, the half-maximum width FWHM(101) of the diffraction peak (101) of the positive electrode material near the diffraction angle 2θ of 36.6° in the powder X-ray diffraction spectrum is 0.080-0.180.

[0019] Preferably, the positive electrode material D V 50Particle size is 3-20μm.

[0020] Preferably, the specific surface area of ​​the positive electrode material is 0.33 to 1.5 m 2 / g;

[0021] And / or the tap density of the positive electrode material is ≥1.9 g / cm 3 ;

[0022] And / or the total free lithium content of the positive electrode material is less than 1800ppm.

[0023] Preferably, in the chemical formula 1, 0.001≤d≤0.04.

[0024] The present invention also provides a method for preparing the high-nickel positive electrode material for lithium-ion batteries, which comprises mixing the raw materials and then performing at least two sintering processes and one coating process.

[0025] Preferably, the first sintering temperature is 700°C to 900°C, preferably 790°C to 890°C; more preferably, the constant temperature time is 8 to 40 hours;

[0026] and / or, the second sintering temperature is 400° C. to 800° C., preferably 680° C. to 800° C., and more preferably the constant temperature time is 5 to 20 hours;

[0027] More preferably, the sintering atmosphere is oxygen.

[0028] Preferably, the coating treatment is performed before the final sintering.

[0029] Preferably, in the above preparation method, the Li source is a lithium-containing oxide, a lithium-containing fluoride or a lithium-containing salt. Preferably, the Li source is selected from one or more of anhydrous lithium hydroxide, lithium hydroxide monohydrate, lithium carbonate, lithium nitrate, lithium acetate and lithium fluoride.

[0030] Preferably, the precursor D in the raw material v 50The particle size is 2.0~20μm.

[0031] The present invention also provides a high-nickel positive electrode material for a lithium-ion battery, which is prepared by the above-mentioned preparation method.

[0032] The present invention also provides a high-nickel positive electrode material for a lithium-ion battery, which comprises two or more of the above positive electrode materials.

[0033] The present invention also provides a lithium ion battery positive electrode, comprising a current collector and a positive electrode material loaded on the current collector, wherein the positive electrode material is the above-mentioned lithium ion battery high-nickel positive electrode material.

[0034] The present invention also provides a lithium ion battery, comprising a positive electrode, a negative electrode and an electrolyte containing a lithium salt, wherein the positive electrode is the positive electrode of the lithium ion battery mentioned above.

[0035] The present invention also provides the application of the above-mentioned lithium ion battery high-nickel positive electrode material, or the above-mentioned lithium ion battery positive electrode, or the above-mentioned lithium ion battery in the field of digital batteries, power batteries or energy storage batteries.

[0036] In addition, in order to solve the above-mentioned problems in the prior art, the present invention also provides the following second set of technical solutions.

[0037] 1. A method for preparing a high-nickel positive electrode material for a lithium-ion battery, wherein the raw materials are mixed and then sintered at least twice and coated once, wherein the sintering is performed three times, the coating treatment is performed before the third sintering, the first sintering temperature is 700° C. to 900° C., and the raw materials include a Li source, a metal A source and a nickel manganese hydroxide precursor;

[0038] Among them, the high nickel positive electrode material of the lithium ion battery has a porous structure, and its chemical formula 1 is Li 1+a Ni b Mn c A d O 2 Elements of the composition shown, wherein: 0.01≤a≤0.24, 0.79<b≤0.96, 0.01<c≤0.20, 0<d≤0.04; A is a combination of Sr and Al;

[0039] When the high-nickel positive electrode material is measured by nitrogen adsorption method, the BJH pore size distribution curve has a single peak or multi-peak pore size distribution in the pore size range of 1.5-20 nm, and the single point adsorption total pore volume of the high-nickel positive electrode material in the pore size range of 1.5-20 nm is 0.0043 cm 3 / g or less;

[0040] The half-peak width FWHM (101) of the diffraction peak (101) of the high-nickel positive electrode material at a diffraction angle 2θ of 36.6° in the powder X-ray diffraction spectrum is 0.093-0.133.

[0041] 2. The preparation method according to technical solution 1, wherein the first sintering temperature is 790-890°C, and the first sintering constant temperature time is preferably 8-40 hours;

[0042] And / or, the second sintering temperature is 400°C to 800°C, preferably 680°C to 800°C; more preferably, the constant temperature time is 5 to 20 hours;

[0043] More preferably, the sintering atmosphere is oxygen.

[0044] 3. The preparation method according to technical solution 1 or 2, wherein the Li source is a lithium-containing oxide, a lithium-containing fluoride or a lithium-containing salt, and preferably, the Li source is selected from one or more of anhydrous lithium hydroxide, lithium hydroxide monohydrate, lithium carbonate, lithium nitrate, lithium acetate and lithium fluoride.

[0045] 4. A high-nickel positive electrode material for a lithium-ion battery, wherein the material is prepared by the preparation method described in any one of technical solutions 1-3.

[0046] 5. The high nickel positive electrode material for lithium ion batteries according to technical solution 4, wherein the positive electrode material D V 50 particle size is 3-20 μm, and / or,

[0047] The specific surface area of ​​the positive electrode material is 0.33 to 1.5 m 2 / g; and / or,

[0048] The tap density of the positive electrode material is ≥1.9 g / cm 3 and / or,

[0049] The total amount of free lithium in the positive electrode material is less than 1800 ppm.

[0050] 6. A high-nickel positive electrode material for a lithium-ion battery, comprising two or more of the high-nickel positive electrode materials for a lithium-ion battery described in Technical Solution 4 or 5.

[0051] 7. A lithium-ion battery positive electrode, comprising a current collector and a positive electrode material loaded on the current collector, wherein the positive electrode material is the high-nickel positive electrode material for a lithium-ion battery as described in any one of technical solutions 4-6.

[0052] 8. A lithium-ion battery, comprising a positive electrode, a negative electrode and an electrolyte containing a lithium salt, wherein the positive electrode is the positive electrode of the lithium-ion battery described in technical solution 7.

[0053] 9. Application of the high-nickel positive electrode material for lithium-ion batteries described in any one of Technical Solutions 4-6, or the positive electrode for lithium-ion batteries described in Technical Solution 7, or the lithium-ion battery described in Technical Solution 8 in the fields of digital batteries, power batteries or energy storage batteries.

[0054] Beneficial effects of the present invention:

[0055] Compared with conventional lithium-ion battery positive electrode materials, the present invention obtains a modified cobalt-free lithium-ion battery high-nickel positive electrode material by adding modifying elements and performing at least two sintering and one coating treatment. The modified cobalt-free lithium-ion battery has a unique porous structure and crystal structure. The porous structure of the positive electrode material provides more paths for the migration of lithium ions and the paths are shorter, so that the lithium-ion battery not only has a higher capacity and good rate performance, but also the crystal structure makes the material have good structural stability, so that during the charging and discharging process of the lithium-ion battery, the capacity decay is reduced, the cycle performance is good, and the increase in DC internal resistance is small, which effectively balances the capacity, rate and cycle performance of the cobalt-free positive electrode material. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is the pore size distribution curve of the high nickel positive electrode material obtained in Example 7.

[0057] Figure 2 This is the X-ray diffraction pattern of the high-nickel positive electrode material obtained in Example 6. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical scheme and technical effect of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention is described clearly and completely. The embodiments described below are part of the embodiments of the present invention, not all of them. In combination with the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] In the description of the present invention, the term "multimodal" refers to a pore size distribution containing two or more pore volume maxima on the BJH pore size distribution curve, usually with a maximum pore volume of 0.0008 cm 3 / g is even larger.

[0060] In the description of the present invention, the term "unimodal" refers to a pore size distribution containing a pore volume maximum on the BJH pore size distribution curve, usually with a maximum pore volume of 0.0008 cm 3 / g is even larger.

[0061] In order to better understand the above technical solution, the present invention is further described in detail below.

[0062] The present invention provides a high-nickel positive electrode material for lithium-ion batteries. The high-nickel positive electrode material has a porous structure, and its chemical formula 1 is Li 1+a Ni b Mn c A d O 2 Elements of the composition shown, wherein: 0.01≤a≤0.24, 0.79<b≤0.96, 0.01<c≤0.20, 0<d≤0.06; A is selected from any one or two or more of Mn, Co, Al, Zr, Y, Rb, Cs, W, Ce, Mo, Ba, Ti, Mg, Ta, Nb, Ca, V, Sc, Sr and B elements, or selected from phosphorus-containing compounds containing at least one element of Ti, Al, Mg, Zr, La and Li elements.

[0063] In a preferred embodiment of the present invention, when measured by nitrogen adsorption method, the BJH pore size distribution curve has a single peak or multi-peak pore size distribution in the pore size range of 1.5-20 nm, and the total pore volume of the high nickel positive electrode material at a single point adsorption in the pore size range of 1.5-20 nm is 0.01 cm 3 / g, preferably within 0.007cm 3 / g or less.

[0064] In another preferred embodiment of the present invention, the half maximum width FWHM(101) of the diffraction peak (101) of the high-nickel positive electrode material near a diffraction angle 2θ of 36.6° in the powder X-ray diffraction spectrum is 0.080-0.180.

[0065] In another preferred embodiment of the present invention, the high nickel cathode material D V 50Particle size is 3-20μm.

[0066] In another preferred embodiment of the present invention, the specific surface area of ​​the high nickel positive electrode material is 0.33 to 1.5 m 2 / g;

[0067] And / or the tap density of the high nickel positive electrode material is ≥1.9 g / cm 3 ;

[0068] And / or the total amount of free lithium in the high-nickel positive electrode material is less than 1800ppm.

[0069] In another preferred embodiment of the present invention, in the chemical formula 1, 0.001≤d≤0.04.

[0070] The present invention also provides a method for preparing the above-mentioned lithium ion battery positive electrode material, which comprises mixing the raw materials and then performing at least two sintering processes and one coating process.

[0071] Wherein, the raw materials include a Li source, a metal A source and a nickel manganese hydroxide precursor.

[0072] In a preferred embodiment of the present invention, the first sintering temperature is 700°C to 900°C, preferably 790°C to 890°C; more preferably, the constant temperature time is 8 to 40 hours;

[0073] And / or, the second sintering temperature is 400°C to 800°C, preferably 680°C to 800°C; more preferably, the constant temperature time is 5 to 20 hours;

[0074] More preferably, the sintering atmosphere is oxygen.

[0075] In a preferred embodiment of the present invention, in the method for preparing the high-nickel positive electrode material for lithium-ion batteries, the coating treatment is performed before the last sintering.

[0076] In another preferred embodiment of the present invention, in the above preparation method, the Li source is a lithium-containing oxide, a lithium-containing fluoride or a lithium-containing salt. Preferably, the Li source is selected from one or more of anhydrous lithium hydroxide, lithium hydroxide monohydrate, lithium carbonate, lithium nitrate, lithium acetate and lithium fluoride.

[0077] In another preferred embodiment of the present invention, the D of the precursor in the raw material v 50The particle size is 2.0~20μm.

[0078] The present invention also provides a high-nickel positive electrode material for a lithium-ion battery, which is prepared by the above-mentioned preparation method.

[0079] The present invention also provides a high-nickel positive electrode material for a lithium-ion battery, which comprises two or more of the above positive electrode materials.

[0080] The present invention also provides a lithium ion battery positive electrode, comprising a current collector and a positive electrode material loaded on the current collector, wherein the positive electrode material is the above-mentioned lithium ion battery high-nickel positive electrode material.

[0081] The present invention also provides a lithium ion battery, comprising a positive electrode, a negative electrode and an electrolyte containing a lithium salt, wherein the positive electrode is the positive electrode of the lithium ion battery mentioned above.

[0082] The lithium-ion battery of the present invention also includes a diaphragm and an aluminum-plastic film. Specifically, the electrodes include a positive electrode and a negative electrode, and the positive electrode is made of materials including a positive electrode current collector and a positive electrode active material coated on the positive electrode current collector, as well as a binder, a conductive aid, and the like, and the positive electrode active material is the above-mentioned lithium-ion positive electrode material. The negative electrode is made of materials including a current collector and a negative electrode active material coated on the current collector, as well as a binder, a conductive aid, and the like; the diaphragm is a PP / PE film commonly used in the industry, which is used to separate the positive electrode from the negative electrode; the aluminum-plastic film is a container for the positive electrode, the negative electrode, the diaphragm, and the electrolyte.

[0083] The binder includes polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylic (ester) styrene-butadiene rubber, epoxy resin and nylon, etc. and their combinations, and its function is to improve the bonding properties between the positive electrode active material particles and between the positive electrode active material particles and the current collector.

[0084] The conductive additive includes one or more of a carbon-based material, a metal-based material and a conductive polymer. The carbon-based material is one or more of natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black or carbon fiber, the metal-based material is a metal powder or metal fiber of copper, nickel, aluminum or silver, and the conductive polymer is a polyphenylene derivative.

[0085] The present invention also provides the application of the above-mentioned lithium ion battery high-nickel positive electrode material, or the above-mentioned lithium ion battery positive electrode, or the above-mentioned lithium ion battery in the field of digital batteries, power batteries or energy storage batteries.

[0086] The beneficial effects of the present invention are further illustrated by specific examples. The reagents and equipment information used in the following examples are shown in Tables 1 and 2.

[0087] Table 1 Reagent information used in the examples

[0088]

[0089]

[0090] Table 2 Equipment information used in the embodiment

[0091]

[0092] Example 1

[0093] Material mixing: Use a 200L plow mixer, start stirring, add 31.78kg of anhydrous lithium hydroxide, 3.44kg of cerium oxide and 100kg of particle size Dv 50 is 8.5μm nickel manganese hydroxide precursor Ni 0.9 Mn 0.1 (OH) 2 (purchased from Guangdong Yingde Jiana Energy Company), stirred for 2 hours for later use;

[0094] First sintering: Use a 36-meter roller kiln, set the temperature to 840°C, introduce oxygen, and the gas flow rate is 10L / min. Put the mixed materials into a sagger and send them into the roller kiln for sintering. Keep the temperature for 35 hours. Cool the materials to room temperature and crush them with a jet mill to obtain the first sintered semi-finished products.

[0095] Second sintering: Use a 36-meter roller kiln, set the temperature to 700°C, introduce oxygen, and the gas flow rate is 10L / min. The semi-finished products of the first sintering are loaded into a sagger and sent to the roller kiln for sintering. The constant temperature time is 8 hours. The material is cooled to room temperature and crushed with a jet mill to obtain the semi-finished products of the second sintering.

[0096] Coating treatment: put the semi-finished product of the second sintering into a stirring tank, start stirring, add 150 kg of deionized water, add 1.05 kg of tetrabutyl titanate, mix for 50 minutes, and filter to obtain a filter cake;

[0097] The third sintering: a 36-meter roller kiln is used, the temperature is set to 600°C, oxygen is introduced, and the gas flow rate is 10L / min. The coated filter cake is placed in a sagger and sent to the roller kiln for sintering. The constant temperature time is 4 hours. The material is cooled to room temperature, crushed with a jet mill, demagnetized, and sieved to obtain the positive electrode material.

[0098] The chemical formula of the positive electrode material obtained by digestion with dilute hydrochloric acid and detection of nucleic acid by ICP is Li 1.24 Ni 0.9 Mn 0.1 Ti 0.0051 Ce 0.02 O 2 .

[0099] Example 2

[0100] Material mixing: Use a 200L plow mixer, start stirring, add 48.99kg of lithium hydroxide monohydrate, 1.2kg of cobalt oxide and 100kg of nickel manganese hydroxide precursor Ni with a particle size Dv50 of 4μm. 0.8 Mn 0.2 (OH) 2 (purchased from Guangdong Yingde Jiana Energy Company), stirred for 2 hours for later use;

[0101] First sintering: Use a 36-meter roller kiln, set the temperature to 890°C, introduce oxygen, and the gas flow rate is 8L / min. Put the mixed materials into a sagger and send them into the roller kiln for sintering. Keep the temperature for 28 hours. Cool the materials to room temperature and crush them with a jet mill to obtain the first sintered semi-finished products.

[0102] Second sintering: Use a 36-meter roller kiln, set the temperature to 750°C, introduce oxygen, and the gas flow rate is 8L / min. The semi-finished products of the first sintering are loaded into a sagger and sent to the roller kiln for sintering. The constant temperature time is 6 hours. The material is cooled to room temperature and crushed with a jet mill to obtain the semi-finished products of the second sintering.

[0103] Coating treatment: put the semi-finished product of the second sintering into a stirring tank, start stirring, add 120 kg of deionized water, add 1.02 kg of tetrabutyl titanate, mix for 60 minutes, and filter to obtain a filter cake;

[0104] For the third sintering, a 36-meter roller kiln was used with a set temperature of 700°C, oxygen was introduced, and the gas flow rate was 8L / min. The coated filter cake was placed in a sagger and sent to the roller kiln for sintering. The constant temperature time was 5 hours. The material was cooled to room temperature, crushed with a jet mill, demagnetized, and sieved to obtain the positive electrode material.

[0105] The chemical formula of the positive electrode material obtained by digestion with dilute hydrochloric acid and detection of nucleic acid by ICP is Li 1.01 Ni 0.8 Mn 0.2 Co 0.016 Ti 0.0046 O 2 .

[0106] Example 3

[0107] Material mixing: Use a 200L plow mixer, start stirring, add 48.18kg lithium hydroxide monohydrate, 2.319kg tungsten oxide, 2kg cobalt carbonate and 100kg D v 50Nickel manganese hydroxide precursor Ni with a particle size of 15 μm 0.9 Mn 0.1 (OH) 2 (purchased from Guangdong Yingde Jiana Energy Company), stirred for 2 hours for later use;

[0108] First sintering: Use a 36-meter roller kiln, set the temperature to 830°C, introduce oxygen, and the gas flow rate is 15L / min. Put the mixed materials into a sagger and send them into the roller kiln for sintering. Keep the temperature for 30 hours. Cool the materials to room temperature and crush them with a jet mill to obtain the first sintered semi-finished products.

[0109] Coating treatment: put the semi-finished product of the first sintering into a stirring tank, start stirring, add 100 kg of deionized water, add 25.4 kg of rubidium carbonate solution (rubidium carbonate and water are mixed in a ratio of 1:10), mix for 40 minutes, and filter to obtain a filter cake;

[0110] For the second sintering, a 36-meter roller kiln was used with a set temperature of 700°C, oxygen was introduced, and the gas flow rate was 15L / min. The coated filter cake was placed in a sagger and sent to the roller kiln for sintering. The constant temperature time was 9 hours. The material was cooled to room temperature, crushed with a jet mill, demagnetized, and sieved to obtain the positive electrode material.

[0111] The chemical formula of the positive electrode material obtained by digestion with dilute hydrochloric acid and detection of nucleic acid by ICP is Li 1.06 Ni 0.9 Mn 0.1 Co 0.02 W 0.01 R 0.02 O 2 .

[0112] Example 4

[0113] Material mixing: Use a 200L plow mixer, start stirring, add 46.06kg of lithium hydroxide monohydrate and 100kg of nickel manganese hydroxide precursor Ni with a particle size Dv50 of 2.0μm. 0.85 Mn 0.15 (OH) 2 (Purchased from Guizhou Zhongwei Zhengyuan New Materials Co., Ltd.), stirred for 2 h and set aside;

[0114] First sintering: Use a 36-meter track kiln, set the sintering temperature to 840°C, introduce oxygen (oxygen flow rate 12L / min), load the mixed materials into the equipment for the first sintering, keep the temperature constant for 16 hours, cool the materials to room temperature, and crush them with a jet mill to obtain the first sintered semi-finished product;

[0115] Second sintering: Use a 36-meter track kiln, set the sintering temperature to 800°C, introduce oxygen (oxygen flow rate 8L / min), load the semi-finished product obtained by the first sintering into the 36-meter track kiln for the second sintering, keep the temperature constant for 18 hours, cool the material to room temperature, crush it with a jet mill, and then demagnetize it to obtain the semi-finished product of the second sintering;

[0116] Coating treatment: put the semi-finished product of the second sintering into a mixing tank, start stirring, add 100 kg of deionized water, stir for 10 minutes, filter, dry, put the dried semi-finished product into a fusion machine, start stirring, add 1.77 kg of ammonium heptamolybdate, and mix for 30 minutes;

[0117] For the third sintering, a 36-meter orbital kiln was used with the sintering temperature set at 600°C and oxygen introduced (oxygen flow rate 5L / min). The coated material was loaded into the 36-meter orbital kiln for the third sintering. The temperature was kept constant for 10 hours. The material was cooled to room temperature, crushed with a jet mill, demagnetized, and sieved to obtain the positive electrode material.

[0118] The chemical formula of the positive electrode material obtained by digestion with dilute hydrochloric acid and detection of nucleic acid by ICP is Li 1.04 Ni 0.85 Mn 0.15 Mo 0.01 O 2 .

[0119] Example 5

[0120] Material mixing: Use a 200L plow mixer, start stirring, add 46.94kg of lithium hydroxide monohydrate and 100kg of nickel manganese hydroxide precursor Ni with a particle size Dv50 of 14.0μm. 0.85 Mn 0.15 (OH) 2 (Purchased from Guizhou Zhongwei Zhengyuan New Materials Co., Ltd.), stirred for 2 h and set aside;

[0121] First sintering: Use a 36-meter track kiln, set the sintering temperature to 810°C, introduce oxygen (oxygen flow rate 12L / min), load the mixed materials into the equipment for the first sintering, keep the temperature constant for 12 hours, cool the materials to room temperature, and crush them with a jet mill to obtain the first sintered semi-finished product;

[0122] Coating treatment: put the semi-finished product of the first sintering into a mixing tank, start stirring, add 100kg of deionized water, stir for 20min, filter, dry, put the semi-finished product after drying into a fusion machine, start stirring, add 0.4kg of boron trioxide, and mix for 30min;

[0123] For the second sintering, a 36-meter orbital kiln was used with the sintering temperature set at 400°C and oxygen introduced (oxygen flow rate 5L / min). The coated material was loaded into the 36-meter orbital kiln for the third sintering at a constant temperature for 5 hours. The material was cooled to room temperature, demagnetized, and sieved to obtain the positive electrode material.

[0124] The chemical formula of the positive electrode material obtained by digestion with dilute hydrochloric acid and detection of nucleic acid by ICP is Li 1.06 Ni 0.85 Mn 0.15 B 0.005 O 2 .

[0125] Example 6

[0126] Material mixing: Use a 200L plow mixer, start stirring, add 29.07kg anhydrous lithium hydroxide, 2.95kg strontium carbonate and 100kg nickel manganese hydroxide precursor Ni with a Dv50 particle size of 8.0μm. 0.95 Mn 0.05 (OH) 2 (purchased from Guangdong Yingde Jiana Energy Company), stirred for 2 hours for later use;

[0127] First sintering: Use a 36-meter roller kiln, set the temperature to 790°C, introduce oxygen, and the gas flow rate is 10L / min. Put the mixed materials into a sagger and send them into the roller kiln for sintering. Keep the temperature for 40 hours. Cool the materials to room temperature and crush them with a jet mill to obtain the first sintered semi-finished products.

[0128] Coating treatment: put the semi-finished product of the first sintering into a stirring tank, start stirring, add 100 kg of deionized water, add 28.5 kg of magnesium acetate solution (magnesium acetate and water are mixed in a ratio of 1:10), mix for 60 minutes, and filter to obtain a filter cake;

[0129] For the second sintering, a 36-meter roller kiln was used with a set temperature of 680°C, oxygen was introduced, and the gas flow rate was 10L / min. The coated filter cake was placed in a sagger and sent to the roller kiln for sintering. The constant temperature time was 5 hours. The material was cooled to room temperature, crushed with a jet mill, demagnetized, and sieved to obtain the positive electrode material.

[0130] The chemical formula of the positive electrode material obtained by digestion with dilute hydrochloric acid and detection of nucleic acid by ICP is Li 1.14 Ni 0.95 Mn 0.0 5 Sr 0.02 Mg 0.02 O 2 of.

[0131] Example 7

[0132] Material mixing: Use a 200L plow mixer, start stirring, add 48.18kg lithium hydroxide monohydrate, 1.9kg strontium carbonate and 100kg D v 50 Particle size 3.5μm nickel manganese hydroxide precursor Ni 0.9 Mn 0.1 (OH) 2 (purchased from Guangdong Yingde Jiana Energy Company), stirred for 2 hours for later use;

[0133] First sintering: Use a 36-meter roller kiln, set the temperature to 860°C, introduce oxygen, and the gas flow rate is 15L / min. Put the mixed materials into a sagger and send them into the roller kiln for sintering. Keep the temperature for 35 hours. Cool the materials to room temperature and crush them with a jet mill to obtain the first sintered semi-finished products.

[0134] Second sintering: Use a 36-meter roller kiln, set the temperature to 750°C, introduce oxygen, and the gas flow rate is 15L / min. The semi-finished products of the first sintering are loaded into a sagger and sent to the roller kiln for sintering. The constant temperature time is 7 hours. The material is cooled to room temperature and crushed with a jet mill to obtain the semi-finished products of the second sintering;

[0135] Coating treatment: put the semi-finished product of the second sintering into a stirring tank, start stirring, add 100 kg of deionized water, add 8.4 kg of aluminum nitrate nonahydrate solution (aluminum nitrate nonahydrate and water are mixed in a ratio of 1:5), mix for 40 minutes, and filter to obtain a filter cake;

[0136] For the third sintering, a 36-meter roller kiln was used with a set temperature of 700°C, oxygen was introduced, and the gas flow rate was 15L / min. The coated filter cake was placed in a sagger and sent to the roller kiln for sintering. The constant temperature time was 9 hours. The material was cooled to room temperature, crushed with a jet mill, demagnetized, and sieved to obtain the positive electrode material.

[0137] The chemical formula of the positive electrode material obtained by digestion with dilute hydrochloric acid and detection of nucleic acid by ICP is Li 1.1 Ni 0.9 Mn 0.1 Sr 0.015 Al 0.003 O 2 .

[0138] Example 8

[0139] The positive electrode materials obtained in Example 3 and Example 7 were mixed in a mass ratio of 1:1 to obtain a mixed positive electrode material.

[0140] Example 9

[0141] The positive electrode materials obtained in Example 3 and Example 7 were mixed at a mass ratio of 7:3 to obtain a mixed positive electrode material.

[0142] Experimental Example 1

[0143] The performance parameters of the high nickel positive electrode materials obtained in Examples 1-9 were determined according to the following method.

[0144] (1) Pore size distribution curve determination method

[0145] (2) Mike fully automatic specific surface and porosity analyzer (TriStarⅡ3020), put 4g of positive electrode powder material into the sample tube for measurement, and degas it at 200℃ for 1h to fully remove the moisture in the measurement sample. Then, the isotherms of the adsorption side and the desorption side were measured by the nitrogen adsorption method using liquid nitrogen in the range of relative pressure P / P0 (P0 = about 665mmHg) of 0.01-0.995. Using the isotherm on the desorption side, the BJH method was used for calculation to obtain a pore size distribution curve with pore diameter as the horizontal coordinate and pore volume as the vertical coordinate. The pore size distribution curve of the high nickel positive electrode material obtained in Example 7 is as follows Figure 1 As shown by Figure 1 It can be seen that on the pore size distribution curve, there is a single peak in the pore size range of 1.5-20 nm. The pore size range of high nickel positive electrode materials prepared in Examples 1-9 and the single point adsorption total pore volume test results with a pore size of 1.5-20 nm are shown in Table 3.

[0146] (2) Specific surface area determination method

[0147] The specific surface area in the present invention is determined by the gravimetric method in reference to the gas adsorption BET method in GB / T 19587-2004, and is measured by a Micromeritics fully automatic specific surface and porosity analyzer (TriStarⅡ3020). The test results are shown in Table 3.

[0148] (3) Particle size measurement method

[0149] The particle size in the present invention refers to GB / T19077-2016 particle size analysis·laser diffraction method, measured by Malvern, MasterSize 2000 laser particle size analyzer, weigh 1g of powder, add 60ml of pure water, super for 5min, pour the sample into the injector, test, and record the test data. The test results are shown in Table 3.

[0150] Master Size 2000 laser particle size analyzer, detection angle 0-135°, test principle is Mie theory, external ultrasound intensity 40KHz 180W, particle refractive index 1.692, particle absorption rate 1, sample test time 6s, background test snap number 6,000times, shading degree 8-12%.

[0151] (4) XRD test method

[0152] X'Pert PRO MPD analyzer was used, light pipe--Cu target, wavelength 1.54060, Be window; incident light path--Sola slit 0.04rad, divergence slit 1 / 2°, shading plate 10mm, anti-scattering slit 1°; diffraction light path-anti-scattering slit 8.0mm, Sola slit 0.04rad, large Ni filter; scanning range 10°-80°, scanning step length 0.013°, dwell time per step 30.6s, voltage 40kV, current 40mA, analysis software High-Score Plus. Example 6 The X-ray diffraction pattern of the high nickel positive electrode material obtained is as follows Figure 2 As shown, the test results of the half-maximum width FWHM (101) corresponding to the (101) diffraction peak near the diffraction angle 2θ of 36.6° of the high-nickel positive electrode material prepared in Examples 1-9 are shown in Table 3.

[0153] (5) Test method for tap density

[0154] Use a 100ml measuring cylinder to weigh m (50g ± 0.5g) of powder, put it into the measuring cylinder, let the material fill the bottom of the measuring cylinder, read the scale on the upper edge of the material, and record it as V 1 , put the measuring cylinder filled with powder on the BT-303 vibration compaction equipment, set the parameters: amplitude 3±0.1mm, vibration number 3000 times, turn on the equipment, after the vibration is finished, remove the measuring cylinder and read the scale V on the upper edge of the powder 2 , tap density = (V 1 -V 2 ) / m. The test results are shown in Table 3.

[0155] (6) Test method for total free lithium content

[0156] Accurately weigh 30g±0.01g of sample, put the sample into a 250ml conical flask, put it into a magnetic stirrer, add 100ml deionized water; put the conical flask on the magnetic stirrer, turn on the stirrer and stir for 30 minutes; filter the mixed solution with shaped filter paper and funnel; use a 50ml pipette to transfer 50ml of filtrate, put it into a 100ml beaker, and put in a magnet; put the beaker on the magnetic stirrer, add 2 drops of phenolphthalein indicator; titrate with 0.05mol / L hydrochloric acid standard titration solution until the color of the solution changes from red to colorless, and record the volume V of 0.05mol / L hydrochloric acid standard titration solution 1(End point 1); add 2 drops of methyl red indicator, the indicator color changes from colorless to yellow; titrate with 0.05mol / L hydrochloric acid standard titration solution until the color of the solution changes from yellow to orange; place the beaker on a heating furnace and heat until the solution boils (the color of the solution changes from orange to yellow); remove the beaker and cool to room temperature; place the beaker on a magnetic stirrer and titrate with 0.05mol / L hydrochloric acid standard titration solution until the color of the solution changes from yellow to light red, and record the volume V of the 0.05mol / L hydrochloric acid standard titration solution 2 (End point 2) The total free lithium content was calculated according to the following formula. The test results are shown in Table 3.

[0157] Total free lithium: Li + (wt%) = V 2 ×0.05×6.94×2×100 / (m×1000);

[0158] m---is the mass of the sample in g;

[0159] V 2 --- is the second titration endpoint;

[0160] 6.94 – The atomic weight of lithium.

[0161] Table 3 Performance parameter test results of high nickel positive electrode materials prepared in Examples 1-9

[0162]

[0163]

[0164] Experimental Example 2

[0165] Preparation and performance evaluation of lithium-ion batteries.

[0166] Prepare 454261 soft pack batteries according to the following method:

[0167] Positive electrode preparation: The high-nickel positive electrode material prepared in Examples 1-9 of the present invention, conductive carbon black (SP), and binder polyvinylidene fluoride (PVDF) were added to N-methylpyrrolidone (NMP) (the weight ratio of the positive electrode material to NMP was 2.1:1) in a weight ratio of 94:3:3, mixed thoroughly, stirred to form a uniform slurry, coated on an aluminum foil current collector, dried, and pressed into a pole sheet.

[0168] Negative electrode preparation: Add negative electrode artificial graphite, conductive carbon black (SP), carboxymethyl cellulose (CMC), and adhesive (SBR) in a weight ratio of 95:1:1:3 into sufficient pure water, stir to form a uniform slurry, coat it on the copper foil current collector, dry and press into a pole piece.

[0169] The diaphragm is made of PP / PE composite film material. The pressed positive and negative electrodes are spot welded to the upper tabs, and after inserting the diaphragm, they are wound on the winder and loaded into the soft pack fixture, and the top and side are sealed, and then placed in an oven for baking. After that, 9g of electrolyte is injected in an environment with a relative humidity of less than 1.5%. The electrolyte uses a mixed solvent with a mass ratio of EC:DEC:DMC=1:1:1, and the electrolyte is 1M lithium hexafluorophosphate. After injection and formation for 48 hours, vacuum sealing is performed. The battery cell model is 454261.

[0170] The battery performance was tested on a Hangke battery tester according to the following method.

[0171] 1) Capacity test

[0172] Connect the prepared soft-pack battery to the test stand and start the test program. Setting steps: Set the test temperature to 25℃, let it stand for 4 hours, charge it at constant current and constant voltage for 4 hours (such as 1 / 3C, charge to 4.2V), pause, let it stand, discharge it at constant current (such as 1 / 3C, end voltage 3.0V), get the capacity under the current and voltage, repeat the previous steps, and you can get the capacity data under different current and voltage conditions.

[0173] 2) Cycle test

[0174] Connect the battery that has passed the above capacity test to the test stand, start the test program, and set the steps: set the test temperature to 45℃, let it stand for 4 hours, charge at constant current for 4 hours (such as 1C, charge to 4.2V), switch to constant voltage charging (such as 4.2V 2h), let it stand for 5 minutes, discharge at constant current for 4 hours (such as 1C, cut-off voltage 3.0V), let it stand for 5 minutes, repeat the previous steps starting from constant current charging, and perform cycle testing to obtain the capacity retention rate of different cycle numbers.

[0175] 3) Cyclic DC resistance (DCR) growth test:

[0176] In the step of the cycle test described in 2), before the constant current discharge, a constant current discharge step of 30 seconds is added (the voltage difference within 30 seconds is recorded, and then divided by the current to obtain the DCR), and the others remain unchanged. Repeat the steps at the beginning of the previous constant current charge and perform the cycle test to obtain the growth rate of DCR at different cycle numbers (the difference between the DCR after this cycle and the DCR after the first cycle is divided by the DCR after the first cycle), and the test results are shown in Table 4.

[0177] 4) Rate performance

[0178] Connect the prepared soft-pack battery to the test stand and start the test program. Setting steps: Set the test temperature to 25℃, let it stand for 4 hours, charge to 4.2V with 1 / 3C constant current and constant voltage, cut off current 0.02C, pause, let it stand, discharge to 3.0V with 1 / 3C, and record the battery's 1 / 3C discharge capacity; let it stand for 4 hours, charge to 4.2V with 1C constant current and constant voltage, cut off current 0.02C, pause, let it stand, discharge to 3.0V with 1C constant current, and record the battery's 1C discharge capacity; let it stand for 4 hours, charge to 4.2V with 2C constant current and constant voltage, cut off current 0.02C, pause, let it stand, discharge to 3.0V with 2C constant current, and record the battery's 2C discharge capacity.

[0179] Table 4 Cycle performance test results

[0180]

[0181]

[0182] As shown in Table 3, the total pore volume of the lithium ion battery high nickel positive electrode materials prepared in Examples 1-9 of the present invention is 0.0043 cm when the pore size is 1.5-20 nm and the single point adsorption is 0.0043 cm 3 / g, the positive electrode material is a porous structure with a pore size range of 1.7-19nm; the tap density of the high nickel positive electrode material prepared by the present invention is greater than 1.9g / cm 3 , with a specific surface area of ​​0.33-0.95m 2 / g,D v 50 particle size is 3.3-17.3μm; XRD diffraction results show that the half-peak width FWHM(101) of the diffraction peak (101) of the positive electrode material in the powder X-ray diffraction spectrum near the diffraction angle 2θ of 36.6° is 0.093-0.133.

[0183] As can be seen from Table 4, the lithium ion battery prepared using the high nickel positive electrode material for lithium ion batteries prepared in Examples 1-9 of the present invention has a capacity of 181-200.7 mAh / g at 1 / 3C current and 4.2V voltage, a discharge specific capacity of 175.3-194.6 mAh / g at 2C current, a capacity retention rate of 87-94% after 200 cycles at 4.2V, and a DCR growth rate of 19-30% after 200 cycles at 4.2V. The high-nickel positive electrode material prepared by the present invention has a smaller pore size, provides more paths for the migration of lithium ions and the paths are shorter, thereby obtaining a higher capacity and better rate performance. The half-peak width FWHM (101) of the diffraction peak (101) of the positive electrode material near the diffraction angle 2θ of 36.6° in the powder X-ray diffraction spectrum is 0.093-0.133, so that the material has better structural stability, better capacity retention rate, and less DC internal resistance growth; Examples 8 and 9 of the present invention use positive electrode materials of different particle sizes to mix, so that the tap density of the high-nickel positive electrode material of the lithium ion battery is further improved, the capacity and cycle performance are better matched, and the DC internal resistance growth is also smaller.

[0184] In summary, compared with conventional lithium-ion battery positive electrode materials, the present invention obtains a modified cobalt-free lithium-ion battery high-nickel positive electrode material by adding modifying elements and at least two sintering and one coating treatment. The modified cobalt-free lithium-ion battery has a unique porous structure and crystal structure. The porous structure of the positive electrode material provides more paths for the migration of lithium ions and the paths are shorter, so that the lithium-ion battery not only has a higher capacity and good rate performance, but also the crystal structure makes the material have good structural stability, so that during the charging and discharging process of the lithium-ion battery, the capacity decay is reduced, the cycle performance is good, and the DC internal resistance increases less, which effectively balances the capacity, rate and cycle performance of the cobalt-free positive electrode material.

[0185] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a high-nickel positive electrode material for a lithium-ion battery, It is characterized in that The method comprises mixing raw materials and then performing at least two sinterings and one coating treatment, wherein the sintering is three sinterings, the coating treatment is performed before the third sintering, the first sintering temperature is 700° C. to 900° C., and the raw materials include a Li source, a metal A source and a nickel manganese hydroxide precursor; Among them, the high nickel positive electrode material of the lithium ion battery has a porous structure, and its chemical formula 1 is Li 1+a Ni b Mn c A d O 2 Elements of the composition shown, wherein: 0.01≤a≤0.24, 0.79<b≤0.96, 0.01<c≤0.20, 0<d≤0.04; A is a combination of Sr and Al; When the high-nickel positive electrode material is measured by nitrogen adsorption method, the BJH pore size distribution curve has a single peak or multi-peak pore size distribution in the pore size range of 1.5-20 nm, and the single point adsorption total pore volume of the high-nickel positive electrode material in the pore size range of 1.5-20 nm is 0.0043 cm 3 / g or less; The half-peak width FWHM (101) of the diffraction peak (101) of the high-nickel positive electrode material at a diffraction angle 2θ of 36.6° in the powder X-ray diffraction spectrum is 0.093-0.

133.

2. The preparation method according to claim 1, It is characterized in that The first sintering temperature is 790-890°C, and the first sintering constant temperature time is preferably 8-40 hours; And / or, the second sintering temperature is 400°C to 800°C, preferably 680°C to 800°C; more preferably, the constant temperature time is 5 to 20 hours; More preferably, the sintering atmosphere is oxygen.

3. The preparation method according to claim 1, It is characterized in that The Li source is a lithium-containing oxide, a lithium-containing fluoride or a lithium-containing salt. Preferably, the Li source is selected from one or more of anhydrous lithium hydroxide, lithium hydroxide monohydrate, lithium carbonate, lithium nitrate, lithium acetate and lithium fluoride.

4. The preparation method according to claim 2, It is characterized in that The Li source is a lithium-containing oxide, a lithium-containing fluoride or a lithium-containing salt. Preferably, the Li source is selected from one or more of anhydrous lithium hydroxide, lithium hydroxide monohydrate, lithium carbonate, lithium nitrate, lithium acetate and lithium fluoride.

5. A high nickel cathode material for lithium-ion batteries, It is characterized in that The compound is prepared by the preparation method according to any one of claims 1 to 4.

6. The lithium-ion battery high-nickel positive electrode material according to claim 5, It is characterized in that The positive electrode material D V 50 particle size is 3-20 μm, and / or, The specific surface area of ​​the positive electrode material is 0.33 to 1.5 m 2 / g; and / or, The tap density of the positive electrode material is ≥1.9 g / cm 3 and / or, The total amount of free lithium in the positive electrode material is less than 1800 ppm.

7. A high nickel cathode material for lithium-ion batteries, It is characterized in that It contains two or more of the high-nickel positive electrode materials for lithium-ion batteries as described in claim 5 or 6.

8. A positive electrode for a lithium-ion battery, It is characterized in that It comprises a current collector and a positive electrode material loaded on the current collector, wherein the positive electrode material is the high-nickel positive electrode material for a lithium-ion battery according to any one of claims 5 to 7.

9. A lithium ion battery, It is characterized in that The invention comprises a positive electrode, a negative electrode and an electrolyte containing a lithium salt, wherein the positive electrode is the positive electrode of the lithium ion battery according to claim 8.

10. Application of the high-nickel positive electrode material for lithium-ion batteries according to any one of claims 5 to 7, or the positive electrode for lithium-ion batteries according to claim 8, or the lithium-ion battery according to claim 9 in the fields of digital batteries, power batteries or energy storage batteries.

Images