CN-121974412-A - High-nickel uniform wide-distribution gradient particle size positive electrode material precursor and preparation method thereof

CN121974412ACN 121974412 ACN121974412 ACN 121974412ACN-121974412-A

Abstract

The invention provides a high-nickel uniform wide-distribution gradient particle size positive electrode material precursor and a preparation method thereof, belonging to the technical field of ternary positive electrode high-nickel precursor materials. The method is characterized in that a full-concentration coprecipitation method is adopted to prepare high sphericity, small-particle-size crystal nucleus, then a continuous opposite impact process is adopted, the small particles are used as opposite impact crystal nucleus to prepare a uniform wide-distribution gradient particle-size positive electrode material precursor, and the prepared ternary (NCM) positive electrode high-nickel precursor material has the characteristics of high sphericity, uniform particle size gradient and high compressive strength, so that the effect of mixing large and small particles is achieved, and the multiplying power performance is improved. Has wide market application prospect.

Inventors

XUN RUIZHI
JI TONGZONG
ZHENG BIN
HUANG YAFAN
YANG FAN
WU YOUZHI
ZHANG LIMING
SHEN JIACHENG
ZHOU ZIGUI

Assignees

浙江海创锂电科技有限公司

Dates

Publication Date: 20260505
Application Date: 20251230

Claims (10)

1. The preparation method of the high-nickel uniform wide-distribution gradient particle size cathode material precursor is characterized by comprising the following steps of: (1) Preparing small-particle-size crystal nucleus, namely preparing nickel cobalt manganese hydroxide crystal nucleus with the granularity of 1-5 mu m by a full-concentration coprecipitation method; (2) Preparing a precursor, namely performing a nickel-cobalt-manganese coprecipitation reaction in an inert atmosphere, and introducing the crystal nucleus obtained in the step (1) into a reaction system to perform hedging until the crystal nucleus reaches a qualified granularity when particles grow to a preset particle size; (3) And (3) post-treatment, namely, post-treating the qualified granularity slurry to obtain the high-nickel anode material precursor with uniform wide-distribution gradient particle size.
2. The preparation method of the high-nickel uniform wide-distribution gradient particle size positive electrode material precursor is characterized in that in the step (1), nickel cobalt manganese hydroxide has a chemical general formula of Ni x Co y Mn (1-x-y) (OH) 2 , wherein x is more than or equal to 0.9 and less than or equal to 1,0.02 and y is more than or equal to 0.06,0.01 and less than or equal to 1-x-y is less than or equal to 0.06, complexing agents for coprecipitation reaction in the steps (1) and (2) are ammonia water, the concentration of the prepared ammonia water of the complexing agent solution is 4-10 mol/L, the precipitant is sodium hydroxide, and the concentration of the prepared sodium hydroxide solution is 4-11 mol/L.
3. The method for preparing a high nickel uniform wide distribution gradient particle size positive electrode material precursor according to claim 1, wherein the total concentration co-precipitation method in step (1) comprises: a) Starting the reaction under the initial liquid level of 60-85% of the volume of the reaction kettle; b) Introducing air in the initial reaction for 0-5h, and continuously reducing the pH value to 0.00-0.25 g/L from 0.5-1.2 g/L.
4. The method for preparing the high-nickel uniform wide-distribution gradient particle size positive electrode material precursor according to claim 3, wherein in the step a), the ammonia value in a base solution is 1.5 g/L-5.0 g/L, and the residual alkali value in the base solution is 0.5 g/L-1.2 g/L; And/or in the step b), the reaction temperature is 42-72 ℃, the stirring rotation speed is 600-300 r/min, the ammonia value is stabilized at 1.8-2.6 g/L in the reaction process, and the pH reduction rate is reduced by 0.01-0.04 per hour.
5. The method for preparing a high nickel uniform wide distribution gradient particle size positive electrode material precursor according to claim 4, wherein in the step b), the reaction temperature is 43-50 ℃.
6. The method for preparing the high-nickel uniform wide-distribution gradient particle size positive electrode material precursor according to claim 1, wherein the particle size range in the step (1) is 1.80-4.5 μm; And/or the particle size range is 2.0-4.0 μm.
7. The preparation method of the high-nickel uniform wide-distribution gradient particle size positive electrode material precursor is characterized in that the ammonia value of the coprecipitation reaction in the step (2) is 1.5-5.0 g/L, the residual alkali is 0.02-0.30 g/L, the reaction temperature is 50-75 ℃, and the stirring rotation speed is 350-150 r/min; and/or, the preset particle size of the coprecipitation reaction in the step (2) is 8-9 mu m, and the qualified particle size range is 9.0-12.0 mu m; And/or, the hedging frequency in the step (2) is 0.50-3.5L/h.
8. The preparation method of the high-nickel uniform wide-distribution gradient particle size positive electrode material precursor is characterized in that the ammonia value of the coprecipitation reaction in the step (2) is 2.7-3.5 g/L, the residual alkali is 0.08-0.13 g/L, the reaction temperature is 65-72 ℃, and the stirring rotation speed is 300-200 r/min; And/or, the qualified particle size range of the coprecipitation reaction in the step (2) is 10.0-11.0 mu m; And/or, the hedging frequency in the step (2) is 1.0-2.7L/h.
9. The method for preparing the high-nickel uniform wide-distribution gradient particle size positive electrode material precursor according to claim 1, wherein in the step (3), the post-treatment comprises drying at 100-140 ℃.
10. A high nickel uniform wide distribution gradient particle size positive electrode material precursor prepared according to the preparation method of any one of claims 1-9.

Description

High-nickel uniform wide-distribution gradient particle size positive electrode material precursor and preparation method thereof Technical Field The invention provides a preparation method of a high nickel uniform wide-distribution gradient particle size positive electrode material precursor, which belongs to the technical field of positive electrode NCM high nickel precursor materials. Background Because the development center of gravity of lithium ion batteries is changed from consumer products to power products, the energy density requirements of new energy automobiles on the power batteries are continuously improved, and high-capacity, high-voltage and high-safety material products become the main stream of future development. The nickel content is increased, the cobalt content is correspondingly reduced, and the cost is saved. However, as the Ni content increases, the high Ni content of the cathode material also causes poor cycle stability of the battery. And the Ni content is increased, so that cracks are easily generated. At present, high nickel materials are mostly prepared into high nickel precursor materials with single particle size or relatively narrow particle size distribution, the materials have low pressure resistance, so that capacity multiplying power is low, and the problems are generally solved by adopting a mode of mixing large and small particles at present, but the mixing process is complex, mechanical damage such as crack generation and material disintegration and the like are easily caused in the mixing process. The prior patent (CN 202310210234.8) discloses a continuous production method for preparing a wide-distribution non-micropowder spherical uniform high-nickel ternary precursor by a seed crystal controlled precipitation method, which uses a continuous method for preparing small particles, then uses a crystal nucleus supplementing method for producing wide-distribution large particles, the particles obtained by the method have serious agglomeration and poor sphericity, Therefore, the invention provides the preparation method of the high-nickel uniform wide-distribution gradient particle size positive electrode material precursor, which aims at solving the problems of serious agglomeration, poor sphericity, low ball cracking and compressive strength caused by increasing the nickel content in order to improve the capacity of the existing wide-distribution ternary precursor, has the characteristics of high sphericity, uniform particle size gradient and high compressive strength, achieves the effect of mixing large and small particles, and improves the rate capability. Disclosure of Invention The invention aims to prepare high sphericity and small-particle-diameter crystal nucleus by adopting a full concentration method on the basis of the existing ternary precursor preparation process, so that the defects of poor sphericity, poor fluidity, fine powder and the like of undershoot small particles prepared by the traditional continuous process are overcome, then the continuous undershoot process is adopted, the small particles are used as undershoot crystal nucleus to prepare the uniform wide-distribution gradient-particle-diameter positive electrode material precursor by the optimized process, and the NCM ternary precursor prepared by the invention has the characteristics of high sphericity, gradient wide distribution of particle sizes, uniform particle diameters of different gradients, strong pressure resistance and the like. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: the preparation method of the high-nickel uniform wide-distribution gradient particle size cathode material precursor comprises the following steps: (1) Preparing small-particle-size crystal nucleus, namely preparing nickel cobalt manganese hydroxide crystal nucleus with the granularity of 1-5 mu m by a full-concentration coprecipitation method; (2) Preparing a precursor, namely performing a nickel-cobalt-manganese coprecipitation reaction in an inert atmosphere, and introducing the crystal nucleus obtained in the step (1) into a reaction system to perform hedging until the crystal nucleus reaches a qualified granularity when particles grow to a preset particle size; (3) And (3) post-treatment, namely, post-treating the qualified granularity slurry to obtain the high-nickel anode material precursor with uniform wide-distribution gradient particle size. The preparation method realizes the preparation of the precursor with gradient wide distribution by introducing the opposite impact of small particles, so that the compression resistance of the precursor is improved, and the preparation method adopts a full concentration method to prepare small-particle-diameter crystal nucleus, compared with the traditional continuous process to prepare small particles, the sphericity is good, the agglomeration is obviously optimized, the fluidity of the particles is enhanced, t