High-dispersion micro-particle high-nickel ternary precursor as well as preparation method and application thereof
By preparing highly dispersed microparticle high-nickel ternary precursors, forming a loose core and monolithic shell structure, the energy density and stability issues of ultra-high nickel ternary precursor materials were solved, achieving improved battery performance and reduced costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-30
- Publication Date
- 2026-04-10
AI Technical Summary
Existing ultra-high nickel ternary precursor materials have limited energy density improvement, poor cycle stability, complex and costly preparation processes, and poor particle size and morphology consistency, resulting in poor battery performance.
A method for preparing a highly dispersed micro-particle high-nickel ternary precursor is adopted. A loose core and a monolayer hydroxide overlapping shell structure are formed through a two-stage reaction. Different surfactants are used to divide the micro-reaction field to control the particle morphology and dispersibility. Combined with lithium source sintering, a highly dispersed micro-particle cathode material is formed.
It improves the dispersibility and particle uniformity of the material, enhances the energy density and cycle stability of the battery, reduces the manufacturing cost, strengthens the lithium-ion insertion/extraction performance, and improves the overall performance of the battery.
Smart Images
Figure CN121823677A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery materials technology, and more specifically, to a highly dispersed microparticle high-nickel ternary precursor, its preparation method, and its application. Background Technology
[0002] Ternary precursor materials play a crucial role in the lithium-ion battery field, serving as key raw materials for the preparation of ternary cathode materials. With the rapid development of the new energy vehicle industry, ternary precursor materials are widely used, providing power support for electric vehicles and contributing to long range and high performance. As the lithium-ion battery industry further develops, the demand for high-performance ternary precursor materials is on the rise. Emerging markets, such as the low-altitude economy, have even higher energy density requirements for ternary battery materials to improve battery energy density, while also ensuring good cycle stability and excellent safety.
[0003] Existing ultra-high nickel ternary precursor materials have certain shortcomings. In terms of performance, some materials offer limited energy density improvement, failing to meet the ever-increasing demand for high capacity; their cycle stability is poor, with significant capacity decay after multiple charge-discharge cycles, affecting battery lifespan. Regarding fabrication processes, some methods struggle to precisely control the particle size and morphology of the precursor, resulting in poor product consistency and impacting overall battery performance. Furthermore, the fabrication process can be complex and costly, limiting large-scale application; and current technologies have not optimized the primary particle size ratio and orientation of ultra-high nickel ternary precursors, easily leading to problems such as long ion migration paths and insufficient structural stability in the cathode material formed by sintering. Summary of the Invention
[0004] The purpose of this invention is to overcome the problems existing in the prior art and provide a highly dispersed microparticle high-nickel ternary precursor, its preparation method, and its application.
[0005] The technical problem solved by this invention is achieved by the following technical solution.
[0006] The present invention provides a highly dispersed microparticle high-nickel ternary precursor, comprising a loose core and a shell covering the surface of the loose core, wherein: the loose core is a hydroxyl oxide core, and the shell is a coating layer formed by overlapping monolayer hydroxides.
[0007] This invention provides a method for preparing the above-mentioned highly dispersed microparticle high-nickel ternary precursor, comprising the following steps: introducing a first metal salt mixed solution and a first precipitant solution into a base liquid to carry out a first-stage reaction to obtain a first slurry, wherein: the first metal salt mixed solution contains anionic surfactant and the first precipitant solution contains cationic surfactant; subsequently, introducing a metal salt solution, an alkaline precipitant solution and an ammonia solution concurrently into the first slurry to carry out a second-stage reaction to obtain a second slurry; and post-processing the second slurry to obtain the highly dispersed microparticle high-nickel ternary precursor.
[0008] This invention provides a high-nickel cathode material, which is obtained by sintering the above-mentioned highly dispersed micro-particle high-nickel ternary precursor with a lithium source; Preferably, the total amount of metal elements in the highly dispersed micro-particle high-nickel ternary precursor and the molar ratio of lithium elements in the lithium source are controlled to be 1:1.02-1.05, the sintering temperature is 500℃-850℃, the sintering time is 8h-24h, and the number of sintering times is 2-4.
[0009] The present invention provides a lithium battery comprising the above-mentioned high-nickel cathode material.
[0010] The present invention has the following beneficial effects: This invention provides a highly dispersed high-nickel ternary precursor of microparticles, its preparation method, and its application. The preparation method of the highly dispersed high-nickel ternary precursor of microparticles includes a two-stage reaction. In the first stage, two surfactants with different properties are added. Utilizing the action of these two surfactants, the reaction system is uniformly divided into numerous micro-reaction fields through bubble formation. This division of micro-reaction fields releases the surface energy of the microparticles formed during the nucleation stage, reducing particle aggregation and thus improving particle dispersibility, forming a highly dispersed nanoscale hydroxyl oxide core. In the second stage, rapid growth forms a near-monolayer radial structure shell. Attached Figure Description
[0011] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0012] Figure 1 A schematic diagram of the structure of a highly dispersed, micro-particle, high-nickel ternary precursor. Figure 2 SEM image of the highly dispersed microparticle high-nickel ternary precursor prepared in Example 1; Figure 3 A magnified SEM image of a portion of the highly dispersed microparticle high-nickel ternary precursor prepared in Example 1; Figure 4 The sphericity statistics of the highly dispersed microparticle high-nickel ternary precursor prepared in Example 1 are shown in the figure. Figure 5 SEM image of the highly dispersed microparticle high-nickel ternary precursor prepared in Comparative Example 1; Figure 6 SEM image of the highly dispersed microparticle high-nickel ternary precursor prepared in Comparative Example 2; Figure 7 SEM image of the highly dispersed microparticle high-nickel ternary precursor prepared in Comparative Example 3. Detailed Implementation
[0013] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0014] The following is a detailed description of a highly dispersed microparticle high-nickel ternary precursor, its preparation method, and its application, provided by embodiments of the present invention.
[0015] In a first aspect, the present invention provides a highly dispersed microparticle high-nickel ternary precursor, comprising a loose core and a shell covering the surface of the loose core, wherein: the loose core is a hydroxyl oxide core, and the shell is a coating layer formed by overlapping monolayer hydroxides.
[0016] This invention provides a highly dispersed, high-nickel ternary precursor with microparticles, comprising a loose core and a shell covering the surface of the loose core. The shell, which forms a quasi-monolayer structure in the hydroxyl oxide core, can reduce the interface during the particle reaction process, thereby reducing interfacial energy loss. Furthermore, the shell growth process controls the crystallization state to form a radial structure, which is beneficial for lithium-ion insertion / extraction, thus improving material performance. The synthesized material as a whole exhibits a quasi-monolayer shell-encased loose structure, which is conducive to further capacity utilization.
[0017] In some alternative implementations, the kernel is composed of Ni. x M 1-x OOH, wherein M is selected from at least two of Co, Mn, Mg, Al, V, Mo and W, 0.90 ≤ x < 1.00, and the outer shell is composed of Ni. x M 1-x(OH)2, wherein M is selected from at least two of Co, Mn, Mg, Al, V, Mo and W, and 0.90≤x<1.00.
[0018] In some alternative embodiments, the particle size of the core is 60%-80% of the particle size of the highly dispersed microparticle ternary precursor, and the average particle size of the highly dispersed microparticle ternary precursor is 1-4 μm.
[0019] Secondly, the present invention provides a method for preparing the above-mentioned highly dispersed microparticle high-nickel ternary precursor, comprising the following steps: introducing a first metal salt mixed solution, a first precipitant solution and air into a base liquid to carry out a first-stage reaction to obtain a first slurry, wherein: the first metal salt mixed solution contains anionic surfactant and the first precipitant solution contains cationic surfactant; subsequently, introducing a second metal salt mixed solution, a second precipitant solution and an ammonia solution in parallel into the first slurry to carry out a second-stage reaction to obtain a second slurry; and post-processing the second slurry to obtain the highly dispersed microparticle high-nickel ternary precursor.
[0020] This invention provides a method for preparing the above-mentioned highly dispersed microparticle high-nickel ternary precursor, comprising a two-stage reaction, wherein: in the first stage, a loose hydroxyl oxide core is generated by the oxidation of air, and then a dense hydroxide shell is grown on the surface of the loose core, finally obtaining the highly dispersed microparticle high-nickel ternary precursor.
[0021] In some optional embodiments, the preparation of the base solution includes the following steps: adding pure water to the reaction vessel, introducing air to form several small bubbles in the pure water, then turning on the stirring and heating, and after the temperature reaches the required level, adjusting the pH of the solution in the reaction vessel to 9.5-12.0 using an alkaline solution, thus obtaining the solution; Preferably, the stirring rate of the solution in the reactor is 200 rpm-1200 rpm, the temperature is controlled at 40-80℃, and air is introduced into the bottom liquid to control the oxygen atmosphere ratio in the reactor to be 3%-18%. Since other gases such as ammonia and water vapor will be present in the reactor during the reaction, it is necessary to continuously introduce air into the bottom liquid and control the oxygen ratio in the reactor to generate hydroxyl oxide cores through oxidation reaction.
[0022] In some optional embodiments, the first stage reaction includes: introducing a first metal salt mixed solution, a first precipitant solution and air into the bottom liquid to carry out the first stage reaction, maintaining the pH at 9.5-12.0 during the first stage reaction, stopping the feeding after nucleation is completed in 1-20 hours, the core structure exists in the form of hydroxyl oxides, and after the first stage reaction is completed, the particle size is 60%-80% of the final target particle size; Preferably, the first metal salt mixed solution contains a metal salt and an anionic surfactant, wherein the anionic surfactant includes one or more of SDS, DBS, MES, AGS, and ASEA; the first precipitant solution contains an alkaline substance and a cationic surfactant, wherein the cationic surfactant is CTAB; and the alkaline substance includes one or more of sodium hydroxide, potassium hydroxide, and lithium hydroxide. More preferably, the concentration of the first metal salt mixed solution is 0.1M-2M, the concentration of the anionic surfactant in the first metal salt mixed solution is 0.001M-0.02M, the concentration of the first precipitant solution is 3M-15M, and the concentration of the cationic surfactant in the first precipitant solution is 0.03M-0.15M.
[0023] In some optional embodiments, the second stage reaction includes: after the first stage reaction is completed, a second metal salt mixed solution, a second precipitant solution, and an ammonia solution are introduced concurrently into the first slurry; the ammonia value of the reaction environment is adjusted to 2-15 g / L; the pH is adjusted by increasing the pH by 0.05-0.1 for every 1 g / L increase in ammonia value; the temperature and stirring are maintained consistent with the first stage; and the flow rate of the second metal salt mixed solution is set to 1-3 times the flow rate of the first metal salt mixed solution in the first stage; within 0-2 hours after the second stage reaction is fed, the pH drops rapidly by 0.1-0.5; then, the pH is adjusted to the required value at a rate of 0.005-0.02 per hour as needed; the flow rate of the second precipitant solution is controlled to maintain the required pH environment; the flow rate of the ammonia solution is controlled to maintain the required ammonia value environment; the mixture is continuously added to the reactor; and feeding is stopped after the required particle size is reached. Preferably, the concentration of the second metal salt mixed solution is 0.1M-2M; the concentration of the second precipitant solution is 3M-15M; and the concentration of the ammonia solution is 5M.
[0024] In the preparation of highly dispersed micro-particle high-nickel ternary precursors, the pH value during the co-precipitation reaction is precisely controlled. A second metal salt mixed solution, a second precipitant solution, and an ammonia solution are introduced concurrently into the first slurry. The pH value is rapidly reduced at the beginning of feeding or after a period of reaction to change the growth environment of hydroxide grains. This causes the hydroxide particles formed on the core surface to grow along specific crystal planes, resulting in a monolayer structure. The pH value is then adjusted again to allow the generated monolayer hydroxide to grow along other crystal planes, resulting in a hydroxide material with a complete crystal structure. Finally, a precursor with a unique topography is obtained.
[0025] In some optional embodiments, the method further includes: washing the filter cake obtained by filtering the second slurry with 1-10 times its weight of an alkaline solution, then washing it several times with 1-10 times its weight of deionized water. After the content of various impurities meets the standard, the filter cake is filtered and dried at 100-150°C for 2-48 hours to obtain a dried product.
[0026] Thirdly, the present invention provides a highly dispersed micro-particle high-nickel cathode material, which is obtained by sintering the above-mentioned highly dispersed micro-particle high-nickel ternary precursor with a lithium source. Preferably, the total amount of metal elements in the highly dispersed micro-particle high-nickel ternary precursor and the molar ratio of lithium elements in the lithium source are controlled to be 1:1.02-1.05, the sintering temperature is 500℃-850℃, the sintering time is 8h-24h, and the number of sintering times is 3-4.
[0027] This invention provides a method for preparing the above-mentioned highly dispersed microparticle high-nickel ternary precursor. First, pure water is added to a reaction vessel, and air is introduced to form several small bubbles in the pure water. Then, stirring and heating are started. The pH of the pure water is adjusted to a strongly alkaline state using an alkaline solution. This solution serves as the base liquid, inducing the phase transition process in the early stages of the reaction, making the phase transition process more stable and reducing defects during the phase transition. The synthesis stage employs a segmented synthesis. In the first stage, two surfactants with different properties are added. Utilizing the action of these two different surfactants, and by introducing air, countless small bubbles are formed in the base liquid, uniformly dividing the reaction system into countless micro-reaction fields. This division of micro-reaction fields releases the surface energy of the microparticles formed in the nucleation stage, reducing the aggregation of microparticles and thus improving particle dispersibility, forming a highly dispersed nano-scale hydroxyl oxide core. In the second stage, rapid growth forms a near-monolayer radial structure shell. In this invention, the morphology, sphericity, and size of particles are controlled by regulating the microenvironment surrounding the reaction, thus solving the problem of easy aggregation of small particles and making the prepared micro precursor particles have good sphericity and high dispersibility.
[0028] Fourthly, the present invention provides a lithium battery comprising the above-mentioned highly dispersed microparticle high-nickel cathode material.
[0029] The present invention will be further described below with reference to embodiments.
[0030] A method for preparing a highly dispersed, micro-particle, high-nickel ternary precursor includes the following steps: Solution preparation: Preparation of the first metal salt mixed solution: Prepare a solution with metal salt concentration of 0.1M-2M and anionic surfactant concentration of 0.001M-0.02M by mixing multiple metal salts with deionized water; Preparation of the first precipitant solution: Prepare a solution with an alkaline precipitant and a cationic surfactant using deionized water, wherein the concentration of the alkaline substance is 3M-15M and the concentration of the cationic surfactant is 0.03M-0.15M; Preparation of the second metal salt mixed solution: Prepare a solution with a metal salt concentration of 0.1M-2M using deionized water; Prepare the second precipitant solution: Prepare an alkaline precipitant solution with an alkaline concentration of 3M-15M using deionized water; Prepare an ammonia solution: Dilute the ammonia solution with deionized water to the required concentration and set aside.
[0031] Reaction phase: First stage: Add 0.5-1.0 times the effective volume of the reactor as the base liquid to the reactor, and introduce air to maintain the oxygen content in the reactor greater than 3%. Turn on the stirring and heating, adjust the pH to 9.5-12.0, and keep the stirring rate and the temperature in the reactor stable at a certain value. The first metal salt mixed solution is fed at a flow rate of 0.02-0.1% of the effective volume of the reactor per unit time. The flow rate of the first precipitant solution is controlled to maintain the required pH environment. After nucleation is completed in 1-20 hours, the feeding is stopped to form the material core. The core structure exists in the form of hydroxyl oxides. After the first stage reaction is completed, the particle size is 60%-80% of the final target particle size. Second stage: After the first stage reaction is completed, a second metal salt mixed solution, a second precipitant solution, and an ammonia solution are introduced into the first slurry in parallel. The ammonia value of the reaction environment is adjusted to 2-15 g / L. The pH is adjusted by increasing the pH by 0.05-0.1 for every 1 g / L increase in ammonia value. The temperature and stirring are kept consistent with the first stage. The flow rate of the second metal salt mixed solution is kept at 1-3 times that of the first stage. Within 0-2 hours after the second stage reaction is fed, the pH drops rapidly by 0.1-0.5. Then, the pH is adjusted to the required value at a rate of 0.005-0.02 per hour as needed. The flow rate of the second precipitant solution is controlled to maintain the required pH environment. The components of the second metal salt mixed solution are fed at a flow rate calculated based on the required metal content. The flow rate of the ammonia solution is controlled to maintain the required ammonia value environment. The feed is continuously added to the reactor. Feeding is stopped after the required particle size is reached.
[0032] Post-processing stage: The precipitate generated in the second stage reaction enters a filtration device. The resulting filter cake is washed with 1-10 times its weight of alkaline solution, followed by several washes with 1-10 times its weight of deionized water. After the content of various impurities meets the standards, the filter cake is filtered. It is then dried at 100-150℃ for 2-48 hours to obtain the dried product.
[0033] The metal salts include one or more of nickel sulfate, cobalt sulfate, manganese sulfate, and magnesium sulfate, and optionally, one or more of aluminum sulfate, sodium aluminate, and sodium tungstate.
[0034] The first or second precipitant solution contains an alkaline substance, which includes one or more of sodium hydroxide, potassium hydroxide, and lithium hydroxide.
[0035] The anionic surfactants mentioned above are selected from one or more of SDS, DBS, MES, AGS, and ASEA, and the cationic surfactant is CTAB.
[0036] Example 1 A method for preparing highly dispersed microparticle high-nickel ternary precursors includes the following steps: Solution preparation: Preparation of the first metal salt mixed solution: Prepare a metal mixed salt solution with a metal ion concentration of 2M by mixing nickel sulfate, cobalt sulfate and manganese sulfate with deionized water in a ratio of Ni:Co:Mn = 90:5:5. Then add SDS (sodium dodecyl sulfate) to make the concentration of SDS in the solution 0.02M. Preparation of the first precipitant solution: Prepare a 10M solution of sodium hydroxide with deionized water, and add CTAB (hexadecyltrimethylammonium bromide) to make the concentration of CTAB in the solution 0.05M; Preparation of the second metal salt mixed solution: Nickel sulfate, cobalt sulfate, and manganese sulfate are prepared with deionized water in a ratio of Ni:Co:Mn = 90:5:5 to prepare a metal salt solution with a metal ion concentration of 2M. Prepare the second precipitant solution: Prepare a 10M solution of sodium hydroxide with deionized water; Preparation of complexing agent solution: Dilute the ammonia solution to a concentration of 10M to obtain the complexing agent solution.
[0037] First stage reaction: Add 50L of pure water to the reactor, introduce air into the pure water and control the air flow rate to be twice the reactor volume, turn on the stirring and heating, control the stirring speed to be 900rpm and the temperature to be 80℃, adjust the pH to 11.0 using sodium hydroxide solution, use the solution in the reactor as the base liquid, add the first metal salt mixed solution and the first precipitant solution to the base liquid, control the feed flow rate of the first metal salt mixed solution to be 2L / h, control the pH to be 11.0 during the reaction process, stop feeding after 20 hours of feeding to complete nucleation, the particle size of the slurry at the time of stopping is 1.5μm.
[0038] The second stage of the reaction involved simultaneously introducing a second metal salt mixed solution, a second precipitant solution, and a complexing agent solution into the slurry obtained from the first stage reaction. The feed flow rate of the second metal salt mixed solution was 6 L, and the flow rates of the second precipitant solution and the complexing agent solution were adjusted in real time according to the pH and ammonia values. The ammonia value of the solution in the reactor was adjusted to 4 g / L, and the pH was adjusted to 11.3, while the temperature and stirring rate remained unchanged. Within 1 hour after the reaction was started, the pH rapidly decreased to 10.9, and then the pH was adjusted to 10.6 at a rate of 0.02 pH per hour. The reaction continued until the material grew to 2 μm, at which point the feed was stopped.
[0039] Post-processing stage: The precipitate generated in the second stage reaction is fed into a centrifuge. The resulting filter cake is washed once with 5 times its weight of alkaline solution, and then washed twice with 5 times its weight of deionized water. After all impurities meet the standards, the filter cake is filtered. It is then dried at 140℃ for 24 hours to obtain the dried product. See the schematic diagram below. Figure 1 See SEM image. Figure 2 See the enlarged SEM image for details. Figure 3 Sphericity analysis is shown in Figure 4 As can be seen, the particles are evenly dispersed.
[0040] The total amount of metal elements in the product and the molar ratio of lithium elements in the lithium source were 1:1.04. The sintering temperature was 850℃ and the sintering time was 24h. After one sintering, water washing and coating were performed, and then a second sintering was performed. The resulting cathode material had a 0.1C capacity test result of 211.3mAh / g.
[0041] Example 2 A method for preparing highly dispersed microparticle high-nickel ternary precursors includes the following steps: Solution preparation: Preparation of the first metal salt mixed solution: Nickel sulfate, cobalt sulfate, and manganese sulfate were prepared with deionized water in a ratio of Ni:Co:Mn = 94:4:2 to form a metal ion concentration of 2M. Then, SDS (sodium dodecyl sulfate) was added to make the concentration of SDS in the solution 0.02M. Preparation of the first precipitant solution: Prepare a 10M solution of sodium hydroxide with deionized water, and add CTAB (hexadecyltrimethylammonium bromide) to make the concentration of CTAB in the solution 0.05M; Preparation of the second metal salt mixed solution: Nickel sulfate, cobalt sulfate, and manganese sulfate are prepared with deionized water in a ratio of Ni:Co:Mn = 90:5:5 to prepare a metal salt solution with a metal ion concentration of 2M. Prepare the second precipitant solution: Prepare a 10M solution of sodium hydroxide with deionized water; Preparation of complexing agent solution: Dilute the ammonia solution to a concentration of 10M to obtain the complexing agent solution.
[0042] First stage reaction: Add 50L of pure water to the reactor, introduce air into the pure water and control the air flow rate to be twice the reactor volume, turn on the stirring and heating, control the stirring speed to be 900rpm and the temperature to be 80℃, adjust the pH to 11.2 using sodium hydroxide solution, use the solution in the reactor as the base liquid, add the first metal salt mixed solution and the first precipitant solution to the base liquid, control the feed flow rate of the first metal salt mixed solution to be 2L / h, control the pH to be 11.2 during the reaction process, stop feeding after 20 hours of feeding to complete nucleation, the particle size of the slurry at the time of stopping is 1.5μm.
[0043] The second stage of the reaction involved feeding a second metal salt mixed solution, a second precipitant solution, and a complexing agent solution concurrently into the slurry obtained from the first stage reaction. The feed flow rate of the second metal salt mixed solution was 6 L, and the flow rates of the second precipitant solution and the complexing agent solution were adjusted in real time according to the pH and ammonia values. The ammonia value of the solution in the reactor was adjusted to 4 g / L, and the pH was adjusted to 11.5, while the temperature and stirring rate remained unchanged. Within 1 hour after the reaction was started, the pH rapidly decreased to 11.1, and then the pH was adjusted to 10.8 at a rate of 0.02 pH per hour. The reaction continued until the material grew to 2 μm, at which point the feed was stopped.
[0044] Post-processing stage: The precipitate generated in the second stage reaction is fed into a centrifuge. The resulting filter cake is washed once with 5 times its weight of alkaline solution, and then washed twice with 5 times its weight of deionized water. After all impurities meet the standards, the filter cake is filtered. It is then dried at 140℃ for 24 hours to obtain the dried product.
[0045] The total amount of metal elements in the product and the molar ratio of lithium elements in the lithium source were 1:1.04. The sintering temperature was 850℃ and the sintering time was 24h. After one sintering, water washing and coating were performed, and then a second sintering was performed. The resulting cathode material had a 0.1C capacity test result of 222.8mAh / g.
[0046] Example 3 A method for preparing highly dispersed microparticle high-nickel ternary precursors includes the following steps: Solution preparation: Preparation of the first metal salt mixed solution: Nickel sulfate, cobalt sulfate, and manganese sulfate are prepared with deionized water in a ratio of Ni:Co:Mn = 90:5:5 to form a metal ion concentration of 2M mixed salt solution. Then SDS (sodium dodecyl sulfate) is added to make the concentration of SDS in the solution 0.001M. Preparation of the first precipitant solution: Prepare a 10M solution of sodium hydroxide with deionized water, and add CTAB (hexadecyltrimethylammonium bromide) to make the concentration of CTAB in the solution 0.03M; Preparation of the second metal salt mixed solution: Nickel sulfate, cobalt sulfate, and manganese sulfate are prepared with deionized water in a ratio of Ni:Co:Mn = 90:5:5 to prepare a metal salt solution with a metal ion concentration of 2M. Prepare the second precipitant solution: Prepare a 10M solution of sodium hydroxide with deionized water; Preparation of complexing agent solution: Dilute the ammonia solution to a concentration of 10M to obtain the complexing agent solution.
[0047] First stage reaction: Add 50L of pure water to the reactor, introduce air into the pure water and control the air flow rate to be twice the reactor volume, turn on the stirring and heating, control the stirring speed to be 900rpm and the temperature to be 80℃, adjust the pH to 11.0 using sodium hydroxide solution, use the solution in the reactor as the base liquid, add the first metal salt mixed solution and the first precipitant solution to the base liquid, control the feed flow rate of the first metal salt mixed solution to be 2L / h, control the pH to be 11.0 during the reaction process, stop feeding after 20 hours of feeding to complete nucleation, the particle size of the slurry at the time of stopping is 1.5μm.
[0048] The second stage of the reaction involved simultaneously introducing a second metal salt mixed solution, a second precipitant solution, and a complexing agent solution into the slurry obtained from the first stage reaction. The feed flow rate of the second metal salt mixed solution was 6 L, and the flow rates of the second precipitant solution and the complexing agent solution were adjusted in real time according to the pH and ammonia values. The ammonia value of the solution in the reactor was adjusted to 4 g / L, and the pH was adjusted to 11.3, while the temperature and stirring rate remained unchanged. Within 1 hour after the reaction was started, the pH rapidly decreased to 10.9, and then the pH was adjusted to 10.6 at a rate of 0.02 pH per hour. The reaction continued until the material grew to 2 μm, at which point the feed was stopped.
[0049] Post-processing stage: The precipitate generated in the second stage reaction is fed into a centrifuge. The resulting filter cake is washed once with 5 times its weight of alkaline solution, and then washed twice with 5 times its weight of deionized water. After all impurities meet the standards, the filter cake is filtered. It is then dried at 140℃ for 24 hours to obtain the dried product.
[0050] The total amount of metal elements in the product and the molar ratio of lithium elements in the lithium source were 1:1.04. The sintering temperature was 850℃ and the sintering time was 24h. After one sintering, water washing and coating were performed, and then a second sintering was performed. The resulting cathode material had a 0.1C capacity test result of 212.1mAh / g.
[0051] Example 4 A method for preparing highly dispersed microparticle high-nickel ternary precursors includes the following steps: Solution preparation: Preparation of the first metal salt mixed solution: Nickel sulfate, cobalt sulfate, and manganese sulfate are prepared with deionized water in a ratio of Ni:Co:Mn = 90:5:5 to form a metal ion concentration of 2M mixed salt solution. Then SDS (sodium dodecyl sulfate) is added to make the concentration of SDS in the solution 0.001M. Preparation of the first precipitant solution: Prepare a 10M solution of sodium hydroxide with deionized water, and add CTAB (hexadecyltrimethylammonium bromide) to make the concentration of CTAB in the solution 0.03M; Preparation of the second metal salt mixed solution: Nickel sulfate, cobalt sulfate, and manganese sulfate are prepared with deionized water in a ratio of Ni:Co:Mn = 90:5:5 to prepare a metal salt solution with a metal ion concentration of 2M. Prepare the second precipitant solution: Prepare a 10M solution of sodium hydroxide with deionized water; Preparation of complexing agent solution: Dilute the ammonia solution to a concentration of 10M to obtain the complexing agent solution.
[0052] First stage reaction: Add 50L of pure water to the reactor, introduce air into the pure water and control the air flow rate to be twice the reactor volume, turn on the stirring and heating, control the stirring speed to be 900rpm and the temperature to be 80℃, adjust the pH to 11.0 using sodium hydroxide solution, use the solution in the reactor as the base liquid, add the first metal salt mixed solution and the first precipitant solution to the base liquid, control the feed flow rate of the first metal salt mixed solution to be 2L / h, control the pH to be 11.0 during the reaction process, stop feeding after 20 hours of feeding to complete nucleation, the particle size of the slurry at the time of stopping is 1.5μm.
[0053] The second stage of the reaction involved feeding a second metal salt mixed solution, a second precipitant solution, and a complexing agent solution concurrently into the slurry obtained from the first stage reaction. The feed flow rate of the second metal salt mixed solution was 6 L, and the flow rates of the second precipitant solution and the complexing agent solution were adjusted in real time according to the pH and ammonia values. The ammonia value of the solution in the reactor was adjusted to 10 g / L, and the pH was adjusted to 11.9, while the temperature and stirring rate remained unchanged. Within 1 hour after the reaction was started, the pH rapidly decreased to 11.5, and then the pH was adjusted back to 11.1 at a rate of 0.02 pH per hour. The reaction continued until the material grew to 2 μm, at which point the feed was stopped.
[0054] Post-processing stage: The precipitate generated in the second stage reaction is fed into a centrifuge. The resulting filter cake is washed once with 5 times its weight of alkaline solution, and then washed twice with 5 times its weight of deionized water. After all impurities meet the standards, the filter cake is filtered. It is then dried at 140℃ for 24 hours to obtain the dried product.
[0055] The total amount of metal elements in the product and the molar ratio of lithium elements in the lithium source were 1:1.04. The sintering temperature was 850℃ and the sintering time was 24h. After one sintering, water washing and coating were performed, and then a second sintering was performed. The resulting cathode material had a 0.1C capacity test result of 210.9mAh / g.
[0056] Comparative Example 1 Similar to the steps in Example 1, the only difference is that no two surfactants with different properties are added during the first stage of the reaction. The SEM image of the prepared highly dispersed microparticle high-nickel ternary precursor is shown below. Figure 5 As can be seen, the particle dispersibility is poor.
[0057] Comparative Example 2 Similar to the steps in Example 1, the only difference is that: in the first stage of the reaction, no two surfactants with different properties are added, and in the second stage of the reaction, the pH slowly decreases to 10.9 within 5 hours after the feed. The SEM image of the prepared highly dispersed microparticle high-nickel ternary precursor is shown below. Figure 6 As can be seen, the primary particles are small and form a multi-layered shell, rather than being single-piece primary particles.
[0058] Comparative Example 3 Similar to the steps in Example 1, the only difference being that no air is introduced during the first stage of the reaction. The SEM image of the prepared highly dispersed microparticle high-nickel ternary precursor is shown below. Figure 7 It can be seen that the primary particles have a large diameter and, without the oxidation of air, cannot produce a hydroxyl oxide core.
[0059] The cathode material was obtained by sintering the product with a total metal element molar ratio of 1:1.04 to lithium element in the lithium source, sintering at 850℃ for 24 hours, performing a first sintering, washing and coating with water, and then performing a second sintering.
[0060] Electrochemical performance testing The high-nickel single-crystal ternary cathode materials obtained in Example 1 and Comparative Example 3 were used as cathode materials to fabricate coin cells for electrochemical performance testing. The fabrication method is as follows: The high-nickel single-crystal cathode materials prepared in Example 1 and Comparative Example 3 were stirred in a ratio of cathode material powder: conductive agent (SP): adhesive (PVDF) = 90:5:5 to form a uniformly dispersed cathode slurry. The slurry was then coated, punched, and vacuum dried. A lithium metal sheet was used as the negative electrode material for the counter electrode, and a polypropylene film with micropores was used as the battery separator. A 1:1 solvent volume ratio of ethylene carbonate (EC) / dimethyl carbonate (DMC) and 1 mol / L LiPF6 were used as the electrolyte. The cells were assembled into 2025 button cells in a glove box filled with dry high-purity argon gas and left to stand for 8 hours. After the button batteries were allowed to stand, they were charged and discharged at an ambient temperature of 25°C, at a voltage of 2.6-4.3V, and at a current rate of 0.1C. The electrochemical performance of Examples 1-3 and Comparative Examples 1-5 was tested. The initial discharge efficiency was calculated as: Initial efficiency = Initial discharge specific capacity / Initial charge specific capacity * 100%.
[0061] Capacity test: The button battery was left to stand for 10 minutes in a constant temperature environment of 25℃, then charged to 3.7V at 0.1C, and then discharged at a constant current rate of 0.1C to a voltage of 1.9V. The discharge capacity at this time was recorded.
[0062] The following are the first-efficiency and capacity test results of the cathode materials prepared in Example 1 and Comparative Example 3. Three samples of each product prepared in Example 1 and Comparative Example 3 were tested in parallel three times, and the results are as follows:
[0063] As can be seen from Table 1 above, by synthesizing highly dispersed microparticle cathode materials, this invention not only further enhances the material's capacity but also makes the microparticles more conducive to interfacial contact in solid-state batteries. The capacity of the cathode material can be increased by 1%-3% when sintered.
[0064] As can be seen from the above, this invention provides a highly dispersed, micro-particle, high-nickel ternary precursor. First, pure water is added to a reaction vessel, and air is introduced to form several small bubbles in the pure water. Then, stirring and heating are started. The pH of the pure water is adjusted to a strongly alkaline state using an alkaline solution. This solution serves as the base liquid, inducing the phase transition process in the early stages of the reaction, making the phase transition process more stable and reducing defects during the phase transition. The synthesis stage employs a segmented synthesis. The first stage mainly forms a loose core containing hydroxyl oxides. On the one hand, during the transformation of the material from hydroxide to oxide, there is a water loss process. By directly synthesizing hydroxyl oxides, the energy barrier of the reaction is lowered, making the reaction more complete and improving the material's capacity. The second stage, through rapid growth, forms a near-monolayer shell structure, reducing the interface during the particle reaction process. This reduces interfacial energy loss and, on the other hand, controls the crystallization state during shell growth to form a radial structure, which facilitates lithium-ion insertion / extraction, thereby improving material performance. The synthesized material as a whole exhibits a near-monolayer shell encapsulating a loose structure, which is beneficial for further capacity utilization.
[0065] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A highly dispersed, high-nickel ternary precursor with small particles, characterized in that, It includes a loose core and a shell covering the surface of the loose core, wherein: the loose core is a hydroxyl oxide core, and the shell is a coating layer formed by overlapping monolayer hydroxides.
2. The highly dispersed microparticle high-nickel ternary precursor according to claim 1, characterized in that, The core is composed of Ni x M 1-x OOH, wherein M is selected from at least two of Co, Mn, Mg, Al, V, Mo and W, 0.90 ≤ x < 1.00, and the outer shell is composed of Ni. x M 1-x (OH)2, wherein M is selected from at least two of Co, Mn, Mg, Al, V, Mo and W, and 0.90≤x<1.
00.
3. The highly dispersed microparticle high-nickel ternary precursor according to claim 1, characterized in that, The particle size of the core is 60%-80% of the particle size of the highly dispersed micro-particle ternary precursor, and the average particle size of the highly dispersed micro-particle ternary precursor is 1-4 μm.
4. A method for preparing a highly dispersed microparticle high-nickel ternary precursor according to any one of claims 1-3, characterized in that, Includes the following steps: A first metal salt mixed solution, a first precipitant solution, and air are introduced into the base liquid to carry out a first-stage reaction to obtain a first slurry, wherein: the first metal salt mixed solution contains anionic surfactants and the first precipitant solution contains cationic surfactants; subsequently, a second metal salt mixed solution, a second precipitant solution, and an ammonia solution are introduced into the first slurry in parallel to carry out a second-stage reaction to obtain a second slurry; the second slurry is post-treated to obtain a highly dispersed microparticle high-nickel ternary precursor.
5. The preparation method according to claim 4, characterized in that, The preparation of the base liquid includes the following steps: Add pure water to the reaction vessel, introduce air to form several small bubbles in the pure water, then turn on the stirring and heating. After the temperature reaches the required level, use alkaline solution to adjust the pH of the solution in the reaction vessel to 9.5-12.0, and the product is obtained. Preferably, the stirring rate of the solution in the reactor is 200 rpm-1200 rpm, the temperature is controlled at 40-80℃, and air is introduced into the bottom liquid to control the oxygen atmosphere ratio in the reactor to be 3%-18%.
6. The preparation method according to claim 4, characterized in that, The first stage reaction includes: introducing a first metal salt mixed solution, a first precipitant solution, and air into the bottom liquid to carry out the first stage reaction, maintaining the pH at 9.5-12.0 during the first stage reaction process, stopping the feeding after nucleation is completed in 1-20 hours, the core structure exists in the form of hydroxyl oxides, and after the first stage reaction is completed, the particle size is 60%-80% of the final target particle size; Preferably, the first metal salt mixed solution contains a metal salt and an anionic surfactant, wherein the anionic surfactant includes one or more of SDS, DBS, MES, AGS, and ASEA; the first precipitant solution contains an alkaline substance and a cationic surfactant, wherein the cationic surfactant is CTAB; and the alkaline substance includes one or more of sodium hydroxide, potassium hydroxide, and lithium hydroxide. More preferably, the concentration of the first metal salt mixed solution is 0.1M-2M, the concentration of the anionic surfactant in the first metal salt mixed solution is 0.001M-0.02M, the concentration of the first precipitant solution is 3M-15M, and the concentration of the cationic surfactant in the first precipitant solution is 0.03M-0.15M.
7. The preparation method according to claim 4, characterized in that, The second stage reaction includes: after the first stage reaction is completed, a second metal salt mixed solution, a second precipitant solution, and an ammonia solution are introduced into the first slurry in parallel. The ammonia value of the reaction environment is adjusted to 2-15 g / L, and the pH is adjusted by increasing the pH by 0.05-0.1 for every 1 g / L increase in ammonia value. The temperature and stirring are kept consistent with the first stage, and the flow rate of the second metal salt mixed solution is set to 1-3 times the flow rate of the first metal salt mixed solution in the first stage. Within 0-2 hours after the second stage reaction is fed, the pH drops rapidly by 0.1-0.
5. Then, the pH is adjusted to the required value at a rate of 0.005-0.02 per hour as needed. The flow rate of the second precipitant solution is controlled to maintain the required pH environment, and the flow rate of the ammonia solution is controlled to maintain the required ammonia value environment. The solution is continuously added to the reactor, and feeding is stopped after the required particle size is reached. Preferably, the concentration of the second metal salt mixed solution is 0.1M-2M; the concentration of the second precipitant solution is 3M-15M; and the concentration of the ammonia solution is 5M.
8. The preparation method according to claim 4, characterized in that, Post-processing includes: The filter cake obtained by filtering the second slurry is washed with 1-10 times its weight of alkaline solution, and then washed several times with 1-10 times its weight of deionized water. After the content of various impurities meets the standard, the filter cake is filtered and dried at 100-150℃ for 2-48 hours to obtain the dried product.
9. A highly dispersed microparticle high-nickel cathode material, characterized in that, The highly dispersed microparticle high-nickel cathode material is obtained by sintering the highly dispersed microparticle high-nickel ternary precursor according to any one of claims 1-3 with a lithium source; Preferably, the total amount of metal elements in the highly dispersed micro-particle high-nickel ternary precursor and the molar ratio of lithium elements in the lithium source are controlled to be 1:1.02-1.05, the sintering temperature is 500℃-850℃, the sintering time is 8h-24h, and the number of sintering times is 2-4.
10. A lithium battery, characterized in that, Including the highly dispersed microparticle high-nickel cathode material as described in claim 9.