WO2024066892A1 - Manganese-rich oxide precursor, preparation method therefor, and use thereof - Google Patents

Manganese-rich oxide precursor, preparation method therefor, and use thereof Download PDF

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WO2024066892A1
WO2024066892A1 PCT/CN2023/115997 CN2023115997W WO2024066892A1 WO 2024066892 A1 WO2024066892 A1 WO 2024066892A1 CN 2023115997 W CN2023115997 W CN 2023115997W WO 2024066892 A1 WO2024066892 A1 WO 2024066892A1
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manganese
oxide precursor
precursor
solution
rich
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PCT/CN2023/115997
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Chinese (zh)
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胡进
胡伟
彭威
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巴斯夫杉杉电池材料有限公司
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    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01GCOMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00Compounds of nickel
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/36Selection of substances as active materials, active masses, active liquids
    • H01M4/48Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries

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  • the present invention belongs to the field of lithium ion battery materials, and in particular relates to a precursor of a lithium ion battery positive electrode material and a preparation method and application thereof.
  • lithium-rich manganese-based material is not only low in price but also safer than conventional ternary materials. It can well meet the use requirements of electric vehicles, energy storage power stations and small electronic products, and is one of the most promising power battery positive electrode materials in the future.
  • Precursors for lithium-rich manganese-based materials generally include carbonate precursors and hydroxide precursors.
  • the reaction system has a high pH and strong corrosiveness.
  • a large amount of N2 is required in the coprecipitation process, and ammonia water is used as a complexing agent.
  • ammonia water is used as a complexing agent.
  • the coprecipitation process of carbonate precursors is ammonia-free, does not involve ammonia-containing wastewater treatment and ammonia-related occupational health issues, and does not require a large amount of nitrogen protection. It has low costs and greater industrialization prospects.
  • the existing carbonate precursors have a high cobalt content and are relatively expensive.
  • a large amount of CO 2 is released during the sintering process of preparing the positive electrode, resulting in unstable batch quality of the obtained positive electrode.
  • the obtained positive electrode material has poor surface area consistency, poor sphericity, and low continuous concentration, which is not conducive to product industrialization.
  • the internal part is loose, and the sintered positive electrode has many internal cracks, and the electrical performance cannot be fully exerted. Therefore, the production process of the existing lithium-rich manganese-based positive electrode material precursor needs to be further improved to obtain a stable positive electrode with good electrochemical performance.
  • the technical problem to be solved by the present invention is to overcome the shortcomings and defects mentioned in the above background technology, provide a manganese-rich oxide precursor with dense seed crystals, good sphericity and higher continuous concentration, and a preparation method thereof, and after applying it to the preparation of positive electrode materials, it can also improve the problems of poor consistency of specific surface area of lithium-rich manganese-based positive electrode materials, internal looseness, and cracks inside the sintered positive electrode materials.
  • the above manganese-rich oxide precursor is preferably a chemical formula of Ni x Mn y Me (1-xy) O z (CO 3 ) m , wherein 0 ⁇ x ⁇ 0.5, 0.5 ⁇ y ⁇ 1, 0 ⁇ z ⁇ 2, 0 ⁇ m ⁇ 1, and Me is a doping element of Co, Mg, One of Al, Zr, W, Fe, and Cu.
  • NiMn2O4 is a spinel composite oxide.
  • Our research shows that spinel-structured lithium nickel manganese oxide is more likely to appear in the positive electrode material prepared from the oxide precursor containing NiMn2O4 , and the electrochemical performance of the obtained positive electrode material is worse than that of the layered lithium-rich manganese-based positive electrode material, especially in terms of capacity.
  • the above-mentioned manganese-rich oxide precursor preferably, has substantially no NiMn2O4 phase peak in the XRD diagram of the manganese-rich oxide precursor.
  • the above-mentioned manganese-rich oxide precursor preferably has an average crack rate of 2% to 10%.
  • the average crack rate is determined by the following method: first polish the sample to be tested to obtain a sample with a smooth surface, then use a field emission scanning electron microscope to obtain a CP electron microscope image, and count the number of cracks in the CP electron microscope under multiple different field of view areas. The number of cracks in the single field of view/total number of particles is recorded as a single crack rate, and then the average value is taken as the average crack rate.
  • the manganese-rich oxide precursor is preferably obtained by pre-sintering a carbonate precursor in steps.
  • the present invention also provides a method for preparing a manganese-rich oxide precursor, comprising the following steps:
  • step (3) using the solution containing crystal nuclei obtained in step (2) as the base liquid, adding the metal salt solution and the precipitant solution prepared in step (1) into the reactor, controlling the reaction temperature and pH value, stirring and concentrating with a concentrator, returning the solid phase after solid-liquid separation to the reactor, repeating the cycle, and stopping feeding after the particle size of the reaction slurry reaches the set value to obtain a seed slurry;
  • step (1) adding the metal salt solution and the precipitant solution prepared in step (1) into the reactor in parallel, controlling the reaction temperature and pH value, and continuously adding the seed slurry synthesized in step (3) into the reactor, controlling the particle size of the material in the reactor by adjusting the flow rate of the seed slurry, until the target particle size is reached, and collecting the overflow material;
  • the nickel salt is selected from one or more of nickel sulfate, nickel chloride, nickel nitrate and nickel acetate
  • the manganese salt is selected from one or more of manganese sulfate, manganese chloride, manganese nitrate and manganese acetate
  • the precipitant solution is selected from one or more of sodium carbonate solution, sodium bicarbonate solution, potassium carbonate solution and potassium bicarbonate solution
  • the metal salt solution also contains Me salt
  • the total concentration of the prepared metal salt is 0.5-3 mol/L
  • the concentration of the prepared precipitant is 0.5-3 mol/L.
  • step (2) under stirring conditions and under normal temperature control (preferably 30°C-50°C), the prepared metal salt solution and the precipitant solution are simultaneously added to the reaction kettle in parallel using a precise metering pump, and the pH of the reaction solution is maintained at 11-13 to prepare crystal nuclei; the particle size D50 of the crystal nuclei is 0.5-1.5 ⁇ m.
  • normal temperature control preferably 30°C-50°C
  • the target particle size of the seed is controlled such that its D50 is the carbonic acid 1/3 to 1/2 of the salt precursor particle size.
  • step (3) the reaction temperature is controlled at 25°C to 55°C, the pH value of the reaction is 7.5 to 9.0, and the stirring rate is controlled at 500 to 1000 rpm/min.
  • step (4) the reaction temperature is controlled at 40°C to 70°C, and the reaction pH is 7.5 to 9.0.
  • the pre-sintering is carried out in at least three steps, the pre-sintering temperature is 200°C to 600°C, and the time is 2 to 8 hours.
  • the pre-sintering temperature is 200°C to 600°C
  • the time is 2 to 8 hours.
  • multi-step sintering is adopted, so that the internal cracks of the obtained oxide precursor are less, the cracks of the final lithium-rich manganese-based positive electrode material are greatly reduced, and the material maintains a good specific surface area consistency, so that the electrochemical properties of the lithium-rich manganese-based positive electrode material are better exerted.
  • the step-by-step pre-sintering specifically includes: first sintering at 200°C to 300°C for 1 to 2 hours, then heating to 300°C to 400°C at a heating rate of 1 to 5°C/min for 1 to 3 hours, and then heating to 450°C to 600°C at a heating rate of 1 to 5°C/min for 1 to 3 hours.
  • the preferred pre-sintering process adopts an optimized sintering temperature mechanism and a slow heating rate, which can release CO 2 to the maximum extent while eliminating the appearance of impure phase NiMn 2 O 4 , so that the electrochemical performance of the lithium-rich manganese-based positive electrode material can be further exerted.
  • a soluble carbonate is used as a precipitant in the co-precipitation reaction, and the crystal nucleus preparation, seed crystal synthesis stage and growth reaction stage are carried out independently.
  • the key parameters of the reaction are preferably adjusted and controlled, such as stirring speed, pH and reaction temperature, and the solid content in the slurry is adjusted.
  • the precipitate after the reaction is separated, washed and dried to obtain a carbonate precursor, which is transferred to a rotary kiln for staged pre-burning to obtain an oxide precursor.
  • the present invention also provides a use of the above-mentioned manganese-rich oxide precursor in the preparation of lithium-rich manganese-based positive electrode materials for lithium-ion batteries.
  • the beneficial effects of the present invention are as follows: the seed crystal reaction of the present invention adopts small-size crystal nuclei, which grow through a concentration process, and the obtained seed crystals are dense and have good sphericity, which can provide a basis for the subsequent preparation of a precursor with good sphericity.
  • the product of the present invention can be further used to improve the problems of poor consistency of specific surface area of lithium-rich manganese-based positive electrode materials, internal looseness, cracks in sintered positive electrode materials, etc., so that the electrical properties of the positive electrode materials can be more fully and completely exerted.
  • FIG. 1 is a 5000-fold FEI-SEM image of the seed crystal of Example 1 of the present invention.
  • FIG. 2 is a 10,000-fold FEI-SEM image of the manganese-rich oxide precursor of Example 1 of the present invention.
  • FIG. 3 is an XRD diagram of the manganese-rich oxide precursor of Example 1 of the present invention.
  • FIG. 4 is a 10,000-fold FEI-SEM image of the manganese-rich carbonate precursor of Comparative Example 1 of the present invention.
  • FIG. 5 is a CP diagram of the manganese-rich oxide precursor of Example 1 of the present invention at a magnification of 5000 times.
  • FIG6 is a CP diagram of the manganese-rich oxide precursor of Comparative Example 3 of the present invention at a magnification of 5000 times.
  • FIG. 7 is an XRD diagram of the manganese-rich oxide precursors of Example 1 of the present invention and Comparative Example 3.
  • Embodiment 1 is a diagrammatic representation of Embodiment 1:
  • a manganese-rich oxide precursor of the present invention is obtained by pre-sintering a Ni 0.34 Mn 0.66 CO 3 precursor in steps, and contains a nickel oxide phase and a manganese oxide phase.
  • the FWHW (211) of the manganese-rich oxide precursor is 0.35, and the BET of the manganese-rich oxide precursor is 65.4 m 2 /g.
  • the manganese-rich carbonate precursor obtained in the above step (5) is pre-sintered in a rotary kiln, wherein the sintering system is 300°C pre-sintering for 2h, 400°C pre-sintering for 2h, and 450°C pre-sintering for 3h, and the heating rate during the pre-sintering is controlled at 2°C/min, thereby obtaining the target oxide precursor Ni 0.34 Mn 0.66 O z (CO 3 ) m of this embodiment, wherein the nickel-manganese metal molar ratio can be determined by ICP-AES detection, and combined with the main metal content and XRD, it can be known that the synthesized oxide precursor contains carbonate, and the specific content cannot be accurately obtained according to XRD.
  • the FEI-SEM image of the 5000-fold seed crystal obtained in this embodiment is shown in Figure 1
  • the 10000-fold target oxide precursor is shown in Figure 2
  • the XRD image of the target oxide precursor obtained in this embodiment is shown
  • a preparation method of a manganese-rich carbonate precursor comprises the following steps:
  • the 10,000-fold FEI-SEM image of the carbonate precursor prepared in this comparative example is shown in FIG4 .
  • Comparative Example 2 The specific implementation method, operation steps and process parameter conditions of Comparative Example 2 are basically the same as those of Example 1, except that the process of step (6) in Example 1 is not implemented, and a manganese-rich carbonate precursor is directly prepared.
  • Comparative Example 1 The specific implementation method, operation steps and process parameter conditions of Comparative Example 1 are basically the same as those of Example 1, except that step (6) in Example 1 is replaced by: sintering the manganese-rich carbonate precursor obtained in step (5) at 650° C. in a rotary kiln for 6 hours to obtain the target oxide precursor.
  • Comparative Example 1 the precursor prepared by adjusting the pH to control the particle size without adding the seed crystal prepared by the crystal nucleus has a wide distribution, a low tap density, a large specific surface area, and a sphericity worse than that of Example 1. It can be seen from Example 1 and Comparative Example 2 that as the pre-oxidation releases carbon dioxide, the main metal content in the precursor increases, and the oxide precursor after pre-oxidation inherits the particle size and distribution of the carbonate precursor, while the specific surface area tends to decrease, which is more conducive to the preparation of a stable positive electrode material.
  • Example 1 and Comparative Example 2 Three samples of the precursors of Example 1 and Comparative Example 2 were taken and mixed evenly with lithium carbonate at a molar ratio of metal to lithium of 1:1.3, and then sintered at 900°C for 6 hours in an oxygen atmosphere in a box furnace, and then sintered at 500°C for 5 hours, and then cooled to room temperature and removed from the furnace. After crushing and screening, lithium-rich manganese-based positive electrode materials were obtained.
  • the physical parameters of each positive electrode material sample, such as the specific surface area, are shown in Table 2 below.
  • the positive electrode material prepared by the carbonate precursor has poor BET consistency and large differences between different samples.
  • the positive electrode material obtained by the technical solution provided by the present invention has good consistency and is more conducive to industrialization.
  • Example 1 and Comparative Example 3 were polished using an argon ion beam to obtain samples with smooth surfaces, and the CP electron microscope was obtained using a field emission scanning electron microscope as shown in Figures 5 and 6 to observe the internal cracks. By counting the number of cracks in the 5000x CP electron microscope in three different areas, the number of cracks/total number of particles in the field of view was recorded as the crack rate, and the average value was taken as the average crack rate.
  • the internal crack conditions of Example 1 and Comparative Example 3 are shown in Table 3 below. From the results in Table 3 below, it can be seen that the average crack rate of Example 1 is 5.4%, and the crack condition is significantly improved compared with Comparative Example 3.
  • Example 3 adopts 650° C. sintering and the peaks of NiMn 2 O 4 (311), (400), (511) and (440) appear, which obviously produces NiMn 2 O 4 phase separation, which has a negative impact on the electrochemical performance.
  • the oxide precursor using the technical solution provided by the present invention does not have the NiMn 2 O 4 phase separation seen in the comparative example, and is more suitable for preparing lithium-rich manganese-based positive electrode materials.
  • Embodiment 2 is a diagrammatic representation of Embodiment 1:
  • a manganese-rich oxide precursor of the present invention is obtained by pre-sintering Ni 0.32 Mn 0.66 Co 0.02 CO 3 precursor in steps, and contains nickel oxide phase and manganese oxide phase.
  • the FWHW (211) of the manganese-rich oxide precursor is 0.37, and the BET of the manganese-rich oxide precursor is 58.2 m 2 /g.
  • the manganese-rich carbonate precursor obtained in the above step (5) is pre-fired in a rotary kiln, wherein the sintering conditions are pre-fired at 300°C for 2h, pre-fired at 400°C for 2h, and pre-fired at 450°C for 3h, and the heating rate during the pre-fired is controlled at 2°C/min, thereby obtaining the target oxide precursor Ni 0.32 Mn 0.66 Co 0.02 O z (CO 3 ) m of this embodiment, wherein the metal molar ratio of nickel, manganese and the doping element cobalt can be determined by ICP-AES detection.
  • Embodiment 3 is a diagrammatic representation of Embodiment 3
  • a manganese-rich oxide precursor of the present invention is obtained by step-by-step sintering of a Ni 0.30 Mn 0.70 CO 3 precursor, and contains a nickel oxide phase and a manganese oxide phase.
  • the FWHW (211) of the manganese-rich oxide precursor is 0.42, and the BET of the manganese-rich oxide precursor is 58.7 m 2 /g.
  • the manganese-rich carbonate precursor obtained in the above step (5) is pre-fired in a rotary kiln, wherein the sintering conditions are pre-fired at 300°C for 2h, pre-fired at 400°C for 3h, and pre-fired at 550°C for 2h, and the heating rate during the pre-fired is controlled at 1°C/min, thereby obtaining the target oxide precursor Ni 0.30 Mn 0.70 O z (CO 3 ) m of this embodiment, wherein the metal molar ratio of nickel to manganese can be determined by ICP-AES detection.
  • Comparative Example 4 The specific implementation method, operation steps and process parameter conditions of Comparative Example 4 are basically the same as those of Example 3, except that the process of step (6) in Example 2 is not implemented, and a manganese-rich carbonate precursor is directly prepared.
  • Embodiment 4 is a diagrammatic representation of Embodiment 4:
  • a manganese-rich oxide precursor of the present invention is obtained by step-by-step sintering of a Ni 0.40 Mn 0.60 CO 3 precursor, and contains a nickel oxide phase and a manganese oxide phase.
  • the FWHW (211) of the manganese-rich oxide precursor is 0.38, and the BET of the manganese-rich oxide precursor is 62.47 m 2 /g.
  • the preparation method of the high-sphericity manganese-rich oxide precursor described in this embodiment comprises the following steps:
  • the manganese-rich carbonate precursor obtained in the above step (5) is pre-fired in a rotary kiln, wherein the sintering conditions are 200°C for 2h, 400°C for 1h, and 500°C for 3h, and the heating rate during the pre-fire is controlled at 3°C/min, thereby obtaining the target oxide precursor Ni 0.40 Mn 0.60 O z (CO 3 ) m of this embodiment.
  • Comparative Example 5 The specific implementation method, operation steps and process parameter conditions of Comparative Example 5 are basically the same as those of Example 4, except that the process of step (6) in Example 4 is not implemented, and a manganese-rich carbonate precursor is directly prepared.
  • the lithium-rich manganese-based positive electrode materials prepared in Examples 1, 3 and 4 of the present invention and Comparative Examples 2, 3, 4 and 5 were uniformly mixed with carbon black and PVDF, and coated on aluminum foil to make positive electrode sheets, which were assembled into CR2025 button batteries with lithium metal sheets, diaphragms and electrolytes in a vacuum glove box.
  • the batteries were tested by an electrochemical performance tester.
  • the discharge capacity was tested at a rate of 0.1C under a charge and discharge limiting voltage of 2.0-4.7V, and the capacity retention rate was then tested at 0.33C for 50 cycles.
  • the charge and discharge specific capacity and capacity retention rate are shown in Table 4 below.
  • the oxide precursor product prepared by the present invention has good density and few internal cracks, and the finally obtained lithium-rich manganese positive electrode material product has uniform and stable BET and excellent electrical properties, and is suitable for industrialization.

Abstract

Provided are a manganese-rich oxide precursor, a preparation method therefor, and use thereof. The precursor contains an oxide phase of nickel and manganese, and the D50, the diameter distance, the FWHW(211) and the BET of the precursor are all controlled within a certain range. Preparation of the manganese-rich oxide precursor comprises: preparing metal salt and precipitant solutions, and firstly preparing a crystal nucleus; then controlling a reaction temperature and a pH value, returning a solid phase after solid-liquid separation to a reaction kettle, repeating the steps, and obtaining a seed crystal after the granularity of a slurry reaches a set value; then adding the metal salt and precipitant solutions in parallel, controlling a reaction temperature and a pH value, meanwhile, continuously adding the seed crystal slurry, and after a target granularity is reached by means of control, obtaining a carbonate precursor by means of solid-liquid separation; and pre-sintering the carbonate precursor in an air atmosphere to obtain an oxide precursor. The manganese-rich oxide precursor can be used for preparing a lithium-rich manganese-based positive electrode material of a lithium ion battery, and the problems of poor specific surface area consistency, internal looseness, cracks and the like of the lithium-rich manganese-based positive electrode material are solved.

Description

富锰氧化物前驱体及其制备方法和应用Manganese-rich oxide precursor and preparation method and application thereof 技术领域Technical Field
本发明属于锂离子电池材料领域,尤其涉及一种锂离子电池正极材料的前驱体及其制备方法和应用。The present invention belongs to the field of lithium ion battery materials, and in particular relates to a precursor of a lithium ion battery positive electrode material and a preparation method and application thereof.
背景技术Background technique
富锂锰基材料作为新一代的锂电正极材料,与常规三元材料相比,不仅价格低,而且安全性好,能够很好满足电动汽车、储能电站和小型电子产品等领域的使用要求,是未来最具有发展前景的动力电池正极材料之一。As a new generation of lithium battery positive electrode material, lithium-rich manganese-based material is not only low in price but also safer than conventional ternary materials. It can well meet the use requirements of electric vehicles, energy storage power stations and small electronic products, and is one of the most promising power battery positive electrode materials in the future.
富锂锰基材料用前驱体一般包括碳酸盐前驱体、氢氧化物前驱体两种。在采用氢氧化物前驱体的共沉淀反应体系中,反应体系pH高、腐蚀性强,为防止锰氧化,共沉淀过程需使用大量的N2,且使用氨水作络合剂,虽然能制备致密程度高、形貌优选的前驱体,但生产成本极高。碳酸盐前驱体的共沉淀过程无氨,不涉及含氨废水处理及涉氨职业健康问题,也不用通大量氮气保护,成本低,产业化前景更大。Precursors for lithium-rich manganese-based materials generally include carbonate precursors and hydroxide precursors. In the coprecipitation reaction system using hydroxide precursors, the reaction system has a high pH and strong corrosiveness. In order to prevent manganese oxidation, a large amount of N2 is required in the coprecipitation process, and ammonia water is used as a complexing agent. Although a precursor with high density and preferred morphology can be prepared, the production cost is extremely high. The coprecipitation process of carbonate precursors is ammonia-free, does not involve ammonia-containing wastewater treatment and ammonia-related occupational health issues, and does not require a large amount of nitrogen protection. It has low costs and greater industrialization prospects.
现有碳酸盐前驱体中钴含量较高,成本相对较高,且在制备正极的烧结过程由于会大量释放CO2,得到的正极批次质量不稳定,尤其是所得的正极材料比表面积一致性差、球形度差、连续集中度低,不利于产品产业化,且内部疏松,烧结的正极内部裂纹多,电性能得不到完全的发挥。因此,现有富锂锰基正极材料前驱体的生产工艺需进一步改善,以得到稳定的电化学性能良好的正极。The existing carbonate precursors have a high cobalt content and are relatively expensive. In addition, a large amount of CO 2 is released during the sintering process of preparing the positive electrode, resulting in unstable batch quality of the obtained positive electrode. In particular, the obtained positive electrode material has poor surface area consistency, poor sphericity, and low continuous concentration, which is not conducive to product industrialization. In addition, the internal part is loose, and the sintered positive electrode has many internal cracks, and the electrical performance cannot be fully exerted. Therefore, the production process of the existing lithium-rich manganese-based positive electrode material precursor needs to be further improved to obtain a stable positive electrode with good electrochemical performance.
发明内容Summary of the invention
本发明所要解决的技术问题是,克服以上背景技术中提到的不足和缺陷,提供一种晶种致密且球形度好、连续集中度更高的富锰氧化物前驱体及其制备方法,以及将其应用于正极材料制备后,还可以改善富锂锰基正极材料比表面积一致性差、内部疏松、烧结的正极材料内部存在裂纹等问题。The technical problem to be solved by the present invention is to overcome the shortcomings and defects mentioned in the above background technology, provide a manganese-rich oxide precursor with dense seed crystals, good sphericity and higher continuous concentration, and a preparation method thereof, and after applying it to the preparation of positive electrode materials, it can also improve the problems of poor consistency of specific surface area of lithium-rich manganese-based positive electrode materials, internal looseness, and cracks inside the sintered positive electrode materials.
为解决上述技术问题,本发明提出的技术方案为一种富锰氧化物前驱体,所述富锰氧化物前驱体含有镍的氧化物相和锰的氧化物相,所述富锰氧化物前驱体的D50为4~13μm,径距span=(D90-D10)/D50控制在1.1~1.4,FWHW(211)为0.3~0.65,所述富锰氧化物前驱体的BET为30~70m2/g。In order to solve the above technical problems, the technical solution proposed by the present invention is a manganese-rich oxide precursor, wherein the manganese-rich oxide precursor contains a nickel oxide phase and a manganese oxide phase, the D50 of the manganese-rich oxide precursor is 4 to 13 μm, the diameter span = (D90-D10)/D50 is controlled at 1.1 to 1.4, the FWHW (211) is 0.3 to 0.65, and the BET of the manganese-rich oxide precursor is 30 to 70 m 2 /g.
上述的富锰氧化物前驱体,优选的,所述富锰氧化物前驱体的化学式为NixMnyMe(1-x-y)Oz(CO3)m,且0<x≤0.5,0.5≤y<1,0<z<2,0<m<1,Me为掺杂元素Co、Mg、 Al、Zr、W、Fe、Cu中的一种。The above manganese-rich oxide precursor is preferably a chemical formula of Ni x Mn y Me (1-xy) O z (CO 3 ) m , wherein 0<x≤0.5, 0.5≤y<1, 0<z<2, 0<m<1, and Me is a doping element of Co, Mg, One of Al, Zr, W, Fe, and Cu.
NiMn2O4为尖晶石型复合氧化物,我们的研究表明,含有NiMn2O4的氧化物前驱体制备的正极材料里更容易出现尖晶石结构的镍锰酸锂,所得正极材料的电化学性能较层状富锂锰基正极材料更差,尤其是在容量方面。上述的富锰氧化物前驱体,优选的,所述富锰氧化物前驱体的XRD图中基本不存在NiMn2O4相峰。 NiMn2O4 is a spinel composite oxide. Our research shows that spinel-structured lithium nickel manganese oxide is more likely to appear in the positive electrode material prepared from the oxide precursor containing NiMn2O4 , and the electrochemical performance of the obtained positive electrode material is worse than that of the layered lithium-rich manganese-based positive electrode material, especially in terms of capacity. The above-mentioned manganese-rich oxide precursor, preferably, has substantially no NiMn2O4 phase peak in the XRD diagram of the manganese-rich oxide precursor.
上述的富锰氧化物前驱体,优选的,所述富锰氧化物前驱体的平均裂纹率为2%~10%。所述平均裂纹率通过以下方法测定:先对待测样品进行抛光,获得表面平滑的样品,再利用场发射扫描电子显微镜得到CP电镜图,通过统计多个不同视野区域下CP电镜里裂纹个数,将该单个视野下裂纹个数/总颗粒数记为单个裂纹率,再取平均值即为平均裂纹率。所述富锰氧化物前驱体优选是由碳酸盐前驱体分步预烧后获得。The above-mentioned manganese-rich oxide precursor preferably has an average crack rate of 2% to 10%. The average crack rate is determined by the following method: first polish the sample to be tested to obtain a sample with a smooth surface, then use a field emission scanning electron microscope to obtain a CP electron microscope image, and count the number of cracks in the CP electron microscope under multiple different field of view areas. The number of cracks in the single field of view/total number of particles is recorded as a single crack rate, and then the average value is taken as the average crack rate. The manganese-rich oxide precursor is preferably obtained by pre-sintering a carbonate precursor in steps.
作为一个总的技术构思,本发明还提供一种富锰氧化物前驱体的制备方法,包括以下步骤:As a general technical concept, the present invention also provides a method for preparing a manganese-rich oxide precursor, comprising the following steps:
(1)配制包括镍盐、锰盐的金属盐溶液,配制包含碳酸根离子的沉淀剂溶液,备用;(1) preparing a metal salt solution including a nickel salt and a manganese salt, and preparing a precipitant solution including carbonate ions, and setting them aside;
(2)利用步骤(1)配制的金属盐溶液和沉淀剂溶液制备得到含晶核的溶液;(2) preparing a solution containing crystal nuclei using the metal salt solution and the precipitant solution prepared in step (1);
(3)以步骤(2)得到的含晶核的溶液作为底液,将步骤(1)中配制的金属盐溶液和沉淀剂溶液加入反应釜中,控制反应温度及pH值,搅拌后采用浓缩机提浓,固液分离后的固相返回到反应釜,循环往复,待反应浆料粒度达到设定值后,停止进料,得到晶种浆料;(3) using the solution containing crystal nuclei obtained in step (2) as the base liquid, adding the metal salt solution and the precipitant solution prepared in step (1) into the reactor, controlling the reaction temperature and pH value, stirring and concentrating with a concentrator, returning the solid phase after solid-liquid separation to the reactor, repeating the cycle, and stopping feeding after the particle size of the reaction slurry reaches the set value to obtain a seed slurry;
(4)再重新将步骤(1)中配制的金属盐溶液和沉淀剂溶液并流加入到反应釜中,控制反应温度及PH值,同时将步骤(3)中合成的晶种浆料连续加入反应釜中,通过调节晶种浆料流量控制反应釜内物料粒度,直至达到目标粒度后,收集溢流料;(4) adding the metal salt solution and the precipitant solution prepared in step (1) into the reactor in parallel, controlling the reaction temperature and pH value, and continuously adding the seed slurry synthesized in step (3) into the reactor, controlling the particle size of the material in the reactor by adjusting the flow rate of the seed slurry, until the target particle size is reached, and collecting the overflow material;
(5)将收集的溢流料进行固液分离,所得固相经洗涤干燥后得到碳酸盐前驱体;(5) separating the collected overflow material into solid and liquid, and washing and drying the obtained solid phase to obtain a carbonate precursor;
(6)将步骤(5)得到的碳酸盐前驱体在空气气氛下经过预烧得到氧化物前驱体。(6) Pre-calcining the carbonate precursor obtained in step (5) in an air atmosphere to obtain an oxide precursor.
上述的制备方法,优选的,步骤(1)中,所述镍盐选自硫酸镍、氯化镍、硝酸镍及乙酸镍中的一种或者几种;所述锰盐选自硫酸锰、氯化锰、硝酸锰及乙酸锰中的一种或几种;所述沉淀剂溶液选自碳酸钠溶液、碳酸氢钠溶液、碳酸钾溶液、碳酸氢钾溶液中的一种或几种,所述金属盐溶液中还含有Me盐,配制的金属盐总浓度为0.5~3mol/L,配制沉淀剂浓度为0.5~3mol/L。In the above-mentioned preparation method, preferably, in step (1), the nickel salt is selected from one or more of nickel sulfate, nickel chloride, nickel nitrate and nickel acetate; the manganese salt is selected from one or more of manganese sulfate, manganese chloride, manganese nitrate and manganese acetate; the precipitant solution is selected from one or more of sodium carbonate solution, sodium bicarbonate solution, potassium carbonate solution and potassium bicarbonate solution, the metal salt solution also contains Me salt, the total concentration of the prepared metal salt is 0.5-3 mol/L, and the concentration of the prepared precipitant is 0.5-3 mol/L.
上述的制备方法,优选的,步骤(2)中,在搅拌条件且常温控制下(优选30℃-50℃),用精确计量泵同时向反应釜中并流加入配制的金属盐溶液和沉淀剂溶液,并使反应液的pH保持在11~13以制备晶核;所述晶核的粒度D50为0.5~1.5μm。In the above-mentioned preparation method, preferably, in step (2), under stirring conditions and under normal temperature control (preferably 30°C-50°C), the prepared metal salt solution and the precipitant solution are simultaneously added to the reaction kettle in parallel using a precise metering pump, and the pH of the reaction solution is maintained at 11-13 to prepare crystal nuclei; the particle size D50 of the crystal nuclei is 0.5-1.5 μm.
上述的制备方法,优选的,步骤(4)中,所述晶种的目标粒度控制其D50为所述碳酸 盐前驱体粒度的1/3~1/2。In the above-mentioned preparation method, preferably, in step (4), the target particle size of the seed is controlled such that its D50 is the carbonic acid 1/3 to 1/2 of the salt precursor particle size.
上述的制备方法,优选的,步骤(3)中,所述反应温度控制在25℃~55℃,反应的pH值为7.5~9.0,搅拌的速率控制为500~1000rpm/min。In the above preparation method, preferably, in step (3), the reaction temperature is controlled at 25°C to 55°C, the pH value of the reaction is 7.5 to 9.0, and the stirring rate is controlled at 500 to 1000 rpm/min.
上述的制备方法,优选的,步骤(4)中,所述反应温度控制在40℃~70℃,反应的pH值为7.5~9.0。In the above preparation method, preferably, in step (4), the reaction temperature is controlled at 40°C to 70°C, and the reaction pH is 7.5 to 9.0.
上述的制备方法,优选的,步骤(6)中,所述预烧至少分三步进行,预烧的温度为200℃~600℃,时间为2~8h。在碳酸盐前驱体与烧结成氧化物过程中,采用多分步烧结,使得得到的氧化物前驱体内部裂纹较少,大大减少最终富锂锰基正极材料的裂纹,且材料保持较好的比表面积一致性,将富锂锰基正极材料的电化学性能较好的发挥出来。In the above preparation method, preferably, in step (6), the pre-sintering is carried out in at least three steps, the pre-sintering temperature is 200°C to 600°C, and the time is 2 to 8 hours. In the process of sintering the carbonate precursor into an oxide, multi-step sintering is adopted, so that the internal cracks of the obtained oxide precursor are less, the cracks of the final lithium-rich manganese-based positive electrode material are greatly reduced, and the material maintains a good specific surface area consistency, so that the electrochemical properties of the lithium-rich manganese-based positive electrode material are better exerted.
更优选的,所述分步预烧具体包括:先在200℃~300℃烧结1~2h,然后以1~5℃/min的升温速率升温到300℃~400℃烧结1~3h,再以1~5℃/min的升温速率升温到450℃~600℃烧结1~3h。优选的预烧结过程采用优化的烧结温度机制,且升温速率较慢,能够最大程度的释放CO2的同时,还可消除杂相NiMn2O4的出现,使得富锂锰基正极材料的电化学性能进一步发挥。More preferably, the step-by-step pre-sintering specifically includes: first sintering at 200°C to 300°C for 1 to 2 hours, then heating to 300°C to 400°C at a heating rate of 1 to 5°C/min for 1 to 3 hours, and then heating to 450°C to 600°C at a heating rate of 1 to 5°C/min for 1 to 3 hours. The preferred pre-sintering process adopts an optimized sintering temperature mechanism and a slow heating rate, which can release CO 2 to the maximum extent while eliminating the appearance of impure phase NiMn 2 O 4 , so that the electrochemical performance of the lithium-rich manganese-based positive electrode material can be further exerted.
本发明的上述制备方法在共沉淀反应中,采用可溶性碳酸盐为沉淀剂,晶核制备、晶种合成阶段和生长反应阶段各自独立进行,在不同阶段通过优选调节和控制反应的关键参数,比如搅拌速度、pH和反应温度及调节料浆中的固含量等,再通过将反应结束后的沉淀物分离、洗涤后烘干得到碳酸盐前驱体,转移至回转炉分段预烧后,即可得到氧化物前驱体。In the above-mentioned preparation method of the present invention, a soluble carbonate is used as a precipitant in the co-precipitation reaction, and the crystal nucleus preparation, seed crystal synthesis stage and growth reaction stage are carried out independently. At different stages, the key parameters of the reaction are preferably adjusted and controlled, such as stirring speed, pH and reaction temperature, and the solid content in the slurry is adjusted. Then, the precipitate after the reaction is separated, washed and dried to obtain a carbonate precursor, which is transferred to a rotary kiln for staged pre-burning to obtain an oxide precursor.
作为一个总的技术构思,本发明还提供一种上述的富锰氧化物前驱体在制备锂离子电池富锂锰基正极材料中的应用。As a general technical concept, the present invention also provides a use of the above-mentioned manganese-rich oxide precursor in the preparation of lithium-rich manganese-based positive electrode materials for lithium-ion batteries.
与现有技术相比,本发明的有益效果为:本发明的晶种反应采用小粒度晶核,通过浓缩工艺生长,所得到的晶种致密且球形度好,可为后续制备球形度好的前驱体提供基础,同时在生长阶段,采用外加晶种的方式,制备得到的碳酸盐前驱体球形度得到进一步的修饰,最终前驱体的球形度好,且径距span=(D90-D10)/D50能够控制在1.1~1.4,分布较常规连续集中度更高。基于产品性能参数的改进,本发明的产品可进一步用于改善富锂锰基正极材料比表面积一致性差、内部疏松、烧结的正极材料内部存在裂纹等问题,使正极材料的电性能得到更充分、更完全的发挥。Compared with the prior art, the beneficial effects of the present invention are as follows: the seed crystal reaction of the present invention adopts small-size crystal nuclei, which grow through a concentration process, and the obtained seed crystals are dense and have good sphericity, which can provide a basis for the subsequent preparation of a precursor with good sphericity. At the same time, in the growth stage, the sphericity of the prepared carbonate precursor is further modified by adding seeds, and the final precursor has good sphericity, and the diameter span = (D90-D10)/D50 can be controlled at 1.1 to 1.4, and the distribution is higher than the conventional continuous concentration. Based on the improvement of product performance parameters, the product of the present invention can be further used to improve the problems of poor consistency of specific surface area of lithium-rich manganese-based positive electrode materials, internal looseness, cracks in sintered positive electrode materials, etc., so that the electrical properties of the positive electrode materials can be more fully and completely exerted.
附图说明BRIEF DESCRIPTION OF THE DRAWINGS
为了更清楚地说明本发明实施例或现有技术中的技术方案,下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍,显而易见地,下面描述中的附图是本发明的一些实施例,对于本领域普通技术人员来讲,在不付出创造性劳动的前提下,还可以根据这些附图 获得其他的附图。In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, they can also refer to these drawings without creative work. Get additional drawings.
图1为本发明实施例1的晶种的5000倍FEI-SEM图。FIG. 1 is a 5000-fold FEI-SEM image of the seed crystal of Example 1 of the present invention.
图2为本发明实施例1的富锰氧化物前驱体的10000倍FEI-SEM图。FIG. 2 is a 10,000-fold FEI-SEM image of the manganese-rich oxide precursor of Example 1 of the present invention.
图3为本发明实施例1的富锰氧化物前驱体的XRD图。FIG. 3 is an XRD diagram of the manganese-rich oxide precursor of Example 1 of the present invention.
图4为本发明对比例1的富锰碳酸盐前驱体的10000倍的FEI-SEM图。FIG. 4 is a 10,000-fold FEI-SEM image of the manganese-rich carbonate precursor of Comparative Example 1 of the present invention.
图5为本发明实施例1的富锰氧化物前驱体的5000倍下的CP图。FIG. 5 is a CP diagram of the manganese-rich oxide precursor of Example 1 of the present invention at a magnification of 5000 times.
图6为本发明对比例3的富锰氧化物前驱体的5000倍下的CP图。FIG6 is a CP diagram of the manganese-rich oxide precursor of Comparative Example 3 of the present invention at a magnification of 5000 times.
图7为本发明实施例1与对比例3的富锰氧化物前驱体的XRD图。FIG. 7 is an XRD diagram of the manganese-rich oxide precursors of Example 1 of the present invention and Comparative Example 3.
具体实施方式Detailed ways
为了便于理解本发明,下文将结合说明书附图和较佳的实施例对本发明做更全面、细致地描述,但本发明的保护范围并不限于以下具体实施例。In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.
除非另有定义,下文中所使用的所有专业术语与本领域技术人员通常理解含义相同。本文中所使用的专业术语只是为了描述具体实施例的目的,并不是旨在限制本发明的保护范围。Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.
除非另有特别说明,本发明中用到的各种原材料、试剂、仪器和设备等均可通过市场购买得到或者可通过现有方法制备得到。Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.
实施例1:Embodiment 1:
一种本发明的富锰氧化物前驱体,该富锰氧化物前驱体由Ni0.34Mn0.66CO3前驱体分步预烧结得到,含有镍的氧化物相和锰的氧化物相,该富锰氧化物前驱体的D50为6.50μm,径距span=(D90-D10)/D50控制在1.22。该富锰氧化物前驱体的FWHW(211)为0.35富锰氧化物前驱体的BET为65.4m2/g。A manganese-rich oxide precursor of the present invention is obtained by pre-sintering a Ni 0.34 Mn 0.66 CO 3 precursor in steps, and contains a nickel oxide phase and a manganese oxide phase. The D50 of the manganese-rich oxide precursor is 6.50 μm, and the diameter span = (D90-D10)/D50 is controlled at 1.22. The FWHW (211) of the manganese-rich oxide precursor is 0.35, and the BET of the manganese-rich oxide precursor is 65.4 m 2 /g.
本实施例所述高球型度富锰氧化物前驱体的制备方法,包括如下步骤:The method for preparing the high-sphericity manganese-rich oxide precursor described in this embodiment comprises the following steps:
(1)采用硫酸镍、硫酸锰为原料,按镍、锰的摩尔比0.34:0.66配制总浓度为2mol/L的金属盐溶液,备用;采用碳酸钠为沉淀剂,配制1.8mol/L的沉淀剂溶液,备用;(1) using nickel sulfate and manganese sulfate as raw materials, preparing a metal salt solution with a total concentration of 2 mol/L according to a molar ratio of nickel to manganese of 0.34:0.66, and using sodium carbonate as a precipitant to prepare a precipitant solution of 1.8 mol/L, and using it for later use;
(2)晶核制备:在100L反应釜中加水至淹没桨叶,加入碳酸钠调节pH至12,反应釜的搅拌桨转速调至1000r/min,反应温度控制在35℃,用精确计量泵同时向反应釜中并流加入步骤(1)中配制的金属盐溶液和沉淀剂溶液,并使反应液的pH保持在11.9-12.1,反应2h,得到D50 0.8μm的晶核的溶液;(2) Preparation of crystal nuclei: water was added to a 100 L reactor until the blades were submerged, sodium carbonate was added to adjust the pH to 12, the speed of the stirring blade of the reactor was adjusted to 1000 r/min, the reaction temperature was controlled at 35°C, and the metal salt solution and the precipitant solution prepared in step (1) were added to the reactor simultaneously and in parallel using a precise metering pump, and the pH of the reaction solution was maintained at 11.9-12.1. The reaction was carried out for 2 h to obtain a solution of crystal nuclei with a D50 of 0.8 μm.
(3)晶种合成:在100L反应釜中加水至淹没桨叶,加入含1kg、D50为0.8μm的晶核的溶液作为底液,加入碳酸钠调节pH至8.5,反应釜的搅拌桨转速调至1000r/min,反应温度控制在35℃,用精确计量泵同时向反应釜中并流加入步骤(1)中配制的金属盐溶液和沉淀剂溶液,并使反应液的pH保持在8.0~8.5,反应釜溢流出的浆料通过浓缩机提浓、固液分离 后的固相返回到反应釜,循环往复,反应过程中不断取样测试粒度,当检测到反应釜内物料的D50达到2.5μm时,停止进料,并继续搅拌陈化2小时后放置于带搅拌的储罐存放;(3) Seed synthesis: water was added to a 100 L reactor until the blades were submerged, a solution containing 1 kg of crystal nuclei with a D50 of 0.8 μm was added as the bottom solution, sodium carbonate was added to adjust the pH to 8.5, the stirring blade speed of the reactor was adjusted to 1000 r/min, the reaction temperature was controlled at 35°C, the metal salt solution and the precipitant solution prepared in step (1) were added to the reactor in parallel with a precise metering pump, and the pH of the reaction solution was maintained at 8.0-8.5. The slurry overflowing from the reactor was concentrated by a concentrator and solid-liquid separation was performed. The solid phase is returned to the reactor, and the cycle is repeated. During the reaction, samples are continuously taken to test the particle size. When the D50 of the material in the reactor is detected to reach 2.5 μm, the feeding is stopped, and the material is stirred and aged for 2 hours before being placed in a storage tank with stirring.
(4)连续法生长:向干净的连续法反应釜加水至溢流口,将反应釜搅拌转速调整到800r/min,反应温度调整到60℃,加入碳酸钠调节母液的pH为8.5,继续用精密计量泵将步骤(1)中配好的金属盐溶液和沉淀剂溶液并流加入到反应釜中,调整沉淀剂溶液的流量,控制反应溶液的pH为8.0~8.5,同时用蠕动泵将步骤(3)中合成的晶种浆料连续进入反应釜,通过调节晶种浆料流量控制反应釜内物料粒度,每间隔2小时取样检测粒度稳定在6.5±0.3μm,径距稳定在1.1~1.4,电镜球形度较好时,收集溢流料;(4) Continuous growth: add water to the overflow port of a clean continuous reactor, adjust the stirring speed of the reactor to 800 r/min, adjust the reaction temperature to 60°C, add sodium carbonate to adjust the pH of the mother liquor to 8.5, continue to use a precision metering pump to add the metal salt solution and the precipitant solution prepared in step (1) to the reactor in parallel, adjust the flow rate of the precipitant solution, and control the pH of the reaction solution to 8.0-8.5. At the same time, use a peristaltic pump to continuously feed the seed slurry synthesized in step (3) into the reactor, and control the particle size of the material in the reactor by adjusting the flow rate of the seed slurry. Take samples every 2 hours to detect that the particle size is stable at 6.5±0.3 μm, and the diameter distance is stable at 1.1-1.4. When the sphericity under the electron microscope is good, collect the overflow material;
(5)将收集的物料用纯水多次洗涤固体物料,然后干燥、过筛,得到球形度好目标粒度6.50μm的富锰碳酸盐前驱体;(5) washing the collected solid material with pure water for multiple times, and then drying and sieving to obtain a manganese-rich carbonate precursor with good sphericity and a target particle size of 6.50 μm;
(6)将上述步骤(5)得到的富锰碳酸盐前驱体在回转炉中进行预烧,其中烧结制度为300℃预烧2h、400℃预烧2h、450℃预烧3h,预烧期间的升温速率均控制在2℃/min,从而得到本实施例的目标氧化物前驱体Ni0.34Mn0.66Oz(CO3)m,其中镍锰金属摩尔比可以通过ICP-AES检测确定,结合金属主含量及XRD可知合成的氧化物前驱体中含有碳酸根,具体含量根据XRD无法精确得到。本实施例制得的晶种的5000倍的FEI-SEM图如图1所示,目标氧化物前驱体的10000倍如图2所示,本实施例制得的目标氧化物前驱体的XRD图如图3所示。(6) The manganese-rich carbonate precursor obtained in the above step (5) is pre-sintered in a rotary kiln, wherein the sintering system is 300°C pre-sintering for 2h, 400°C pre-sintering for 2h, and 450°C pre-sintering for 3h, and the heating rate during the pre-sintering is controlled at 2°C/min, thereby obtaining the target oxide precursor Ni 0.34 Mn 0.66 O z (CO 3 ) m of this embodiment, wherein the nickel-manganese metal molar ratio can be determined by ICP-AES detection, and combined with the main metal content and XRD, it can be known that the synthesized oxide precursor contains carbonate, and the specific content cannot be accurately obtained according to XRD. The FEI-SEM image of the 5000-fold seed crystal obtained in this embodiment is shown in Figure 1, the 10000-fold target oxide precursor is shown in Figure 2, and the XRD image of the target oxide precursor obtained in this embodiment is shown in Figure 3.
对比例1:Comparative Example 1:
一种富锰碳酸盐前驱体的制备,包括以下步骤:A preparation method of a manganese-rich carbonate precursor comprises the following steps:
(1)采用硫酸镍、硫酸锰为原料,按镍、锰的摩尔比0.34:0.66配制总浓度为2.0mol/L的金属盐溶液,备用;采用碳酸钠为沉淀剂,配制1.8mol/L的沉淀剂溶液,备用;(1) using nickel sulfate and manganese sulfate as raw materials, preparing a metal salt solution with a total concentration of 2.0 mol/L according to a molar ratio of nickel to manganese of 0.34:0.66, and using sodium carbonate as a precipitant to prepare a precipitant solution of 1.8 mol/L, and using it for later use;
(2)连续法生长:向干净的连续法反应釜加水至溢流口,将反应釜搅拌转速调整到800r/min,反应温度调整到60℃,加入碳酸钠调节母液的pH为8.5,继续用精密计量泵将步骤(1)中配好的金属盐溶液和沉淀剂溶液并流加入到反应釜中,调整沉淀剂溶液的流量,控制反应溶液的pH为7.5-10.5,通过调节pH控制反应釜粒度,当反应釜粒度D50在5.5-7.5μm,收集溢流料;(2) Continuous growth: Add water to a clean continuous reactor to the overflow port, adjust the stirring speed of the reactor to 800 r/min, adjust the reaction temperature to 60° C., add sodium carbonate to adjust the pH of the mother liquor to 8.5, continue to use a precision metering pump to add the metal salt solution and the precipitant solution prepared in step (1) to the reactor in parallel, adjust the flow rate of the precipitant solution, control the pH of the reaction solution to 7.5-10.5, control the particle size of the reactor by adjusting the pH, and collect the overflow material when the particle size D50 of the reactor is 5.5-7.5 μm;
(3)将收集的物料用纯水多次洗涤,然后干燥、过筛,得到富锰碳酸盐前驱体。(3) The collected material is washed with pure water for multiple times, and then dried and sieved to obtain a manganese-rich carbonate precursor.
本对比例制得的碳酸盐前驱体的10000倍的FEI-SEM图如图4所示。The 10,000-fold FEI-SEM image of the carbonate precursor prepared in this comparative example is shown in FIG4 .
对比例2:Comparative Example 2:
对比例2的具体实施方式、操作步骤及工艺参数条件与上述实施例1基本相同,其区别在于不实施实施例1中步骤(6)的过程,直接制备得到富锰碳酸盐前驱体。 The specific implementation method, operation steps and process parameter conditions of Comparative Example 2 are basically the same as those of Example 1, except that the process of step (6) in Example 1 is not implemented, and a manganese-rich carbonate precursor is directly prepared.
对比例3:Comparative Example 3:
对比例1的具体实施方式、操作步骤及工艺参数条件与上述实施例1基本相同,其区别在于将实施例1中的步骤(6)替换为:将步骤(5)得到的富锰碳酸盐前驱体在回转炉中650℃下烧结6h得到目标氧化物前驱体。The specific implementation method, operation steps and process parameter conditions of Comparative Example 1 are basically the same as those of Example 1, except that step (6) in Example 1 is replaced by: sintering the manganese-rich carbonate precursor obtained in step (5) at 650° C. in a rotary kiln for 6 hours to obtain the target oxide precursor.
以上各前驱体物理指标见下表1。The physical indicators of the above precursors are shown in Table 1 below.
表1:实施例1与其对比例的产品物理指标对比表
Table 1: Comparison of physical indicators of products in Example 1 and its comparative example
由上可见,对比例1,未加由晶核制备的晶种,仅通过调节pH控制粒度制备的前驱体分布宽,振实密度较低,比表大,且球形度差于实施例1。由实施例1与对比例2可知,随着预氧化释放二氧化碳,前驱体中金属主含量上升,预氧化后的氧化物前驱体在继承碳酸盐前驱体粒度大小及分布的同时,比表面积有下降趋势,更有利于制备稳定的正极材料。As can be seen from the above, in Comparative Example 1, the precursor prepared by adjusting the pH to control the particle size without adding the seed crystal prepared by the crystal nucleus has a wide distribution, a low tap density, a large specific surface area, and a sphericity worse than that of Example 1. It can be seen from Example 1 and Comparative Example 2 that as the pre-oxidation releases carbon dioxide, the main metal content in the precursor increases, and the oxide precursor after pre-oxidation inherits the particle size and distribution of the carbonate precursor, while the specific surface area tends to decrease, which is more conducive to the preparation of a stable positive electrode material.
将上述实施例1和对比例2的前驱体各取3个样与碳酸锂按金属与锂的摩尔配比为1:1.3混合均匀后,在箱式炉氧气气氛中先在900℃下烧结6h,然后在500℃下高温烧结5h,然后冷却至室温出炉,经破碎筛分后即得到富锂锰基正极材料。各个正极材料样品的比表面积等物理参数见下表2。Three samples of the precursors of Example 1 and Comparative Example 2 were taken and mixed evenly with lithium carbonate at a molar ratio of metal to lithium of 1:1.3, and then sintered at 900°C for 6 hours in an oxygen atmosphere in a box furnace, and then sintered at 500°C for 5 hours, and then cooled to room temperature and removed from the furnace. After crushing and screening, lithium-rich manganese-based positive electrode materials were obtained. The physical parameters of each positive electrode material sample, such as the specific surface area, are shown in Table 2 below.
表2:实施例和对比例2的正极材料样品的比表面积等物理参数
Table 2: Physical parameters such as specific surface area of positive electrode material samples of Example and Comparative Example 2
通过以上实施例1和对比例2制备的正极材料对比,可以明显得出,碳酸盐前驱体制备的正极材料BET一致性差,不同样品差异大,本发明提供的技术方案得到的正极材料一致性好,更利于产业化。By comparing the positive electrode materials prepared in the above Example 1 and Comparative Example 2, it can be clearly concluded that the positive electrode material prepared by the carbonate precursor has poor BET consistency and large differences between different samples. The positive electrode material obtained by the technical solution provided by the present invention has good consistency and is more conducive to industrialization.
另外,将实施例1和对比例3利用氩离子束对样品进行抛光,获得表面平滑的样品,利用场发射扫描电子显微镜得到CP电镜如图5、如图6所示,观察内部裂纹情况。通过统计三个不同区域5000倍CP电镜里裂纹个数,将该视野下裂纹个数/总颗粒数记为裂纹率,取平均值即为平均裂纹率,实施例1和对比例3内部裂纹情况见下表3。由下表3的结果可知,实施例1平均裂纹率为5.4%,裂纹情况较对比例3有明显改善。In addition, the samples of Example 1 and Comparative Example 3 were polished using an argon ion beam to obtain samples with smooth surfaces, and the CP electron microscope was obtained using a field emission scanning electron microscope as shown in Figures 5 and 6 to observe the internal cracks. By counting the number of cracks in the 5000x CP electron microscope in three different areas, the number of cracks/total number of particles in the field of view was recorded as the crack rate, and the average value was taken as the average crack rate. The internal crack conditions of Example 1 and Comparative Example 3 are shown in Table 3 below. From the results in Table 3 below, it can be seen that the average crack rate of Example 1 is 5.4%, and the crack condition is significantly improved compared with Comparative Example 3.
表3:实施例和对比例3的平均裂纹率测试对比表
Table 3: Comparison table of average crack rate test of Example 3 and Comparative Example 3
通过实施例1和对比例3的XRD图对比可知(参见图7),对比例3采用650℃烧结出现了NiMn2O4的(311)、(400)、(511)及(440)等峰,明显产生了NiMn2O4分相,会对电化学性能有负面影响。采用本发明提供的技术方案的氧化物前驱体无对比例出现的NiMn2O4分相,更适合用于制备富锂锰基正极材料。By comparing the XRD patterns of Example 1 and Comparative Example 3 (see FIG7 ), it can be seen that the comparative example 3 adopts 650° C. sintering and the peaks of NiMn 2 O 4 (311), (400), (511) and (440) appear, which obviously produces NiMn 2 O 4 phase separation, which has a negative impact on the electrochemical performance. The oxide precursor using the technical solution provided by the present invention does not have the NiMn 2 O 4 phase separation seen in the comparative example, and is more suitable for preparing lithium-rich manganese-based positive electrode materials.
实施例2:Embodiment 2:
一种本发明的富锰氧化物前驱体,该富锰氧化物前驱体由Ni0.32Mn0.66Co0.02CO3前驱体分步预烧结得到,含有镍的氧化物相和锰的氧化物相,该富锰氧化物前驱体的D50为6.0μm,径距span=(D90-D10)/D50控制在1.30。该富锰氧化物前驱体的FWHW(211)为0.37富锰氧化物前驱体的BET为58.2m2/g。A manganese-rich oxide precursor of the present invention is obtained by pre-sintering Ni 0.32 Mn 0.66 Co 0.02 CO 3 precursor in steps, and contains nickel oxide phase and manganese oxide phase. The D50 of the manganese-rich oxide precursor is 6.0 μm, and the diameter span = (D90-D10)/D50 is controlled at 1.30. The FWHW (211) of the manganese-rich oxide precursor is 0.37, and the BET of the manganese-rich oxide precursor is 58.2 m 2 /g.
本实施例所述高球型度富锰氧化物前驱体的制备方法,包括如下步骤:The method for preparing the high-sphericity manganese-rich oxide precursor described in this embodiment comprises the following steps:
(1)采用硫酸镍、硫酸锰、硫酸钴为原料,按镍、锰和钴的摩尔比0.32:0.66:0.02配制总浓度为2mol/L的金属盐溶液,备用;采用碳酸钠为沉淀剂,配制2mol/L的沉淀剂溶液,备用;(1) using nickel sulfate, manganese sulfate and cobalt sulfate as raw materials, preparing a metal salt solution with a total concentration of 2 mol/L according to the molar ratio of nickel, manganese and cobalt of 0.32:0.66:0.02, and setting aside; using sodium carbonate as a precipitant, preparing a precipitant solution of 2 mol/L, and setting aside;
(2)晶核制备:在100L反应釜中加水至淹没桨叶,加入碳酸钠调节pH至12,反应釜的搅拌桨转速调至1000r/min,反应温度控制在35℃,用精确计量泵同时向反应釜中并流加入步骤(1)中配制的金属盐溶液和沉淀剂溶液,并使反应液的pH保持在11.9-12.1,反应2h,得到D50 0.8μm的晶核的溶液; (2) Preparation of crystal nuclei: water was added to a 100 L reactor until the blades were submerged, sodium carbonate was added to adjust the pH to 12, the speed of the stirring blade of the reactor was adjusted to 1000 r/min, the reaction temperature was controlled at 35° C., the metal salt solution and the precipitant solution prepared in step (1) were added to the reactor simultaneously by a precise metering pump, and the pH of the reaction solution was maintained at 11.9-12.1, and the reaction was carried out for 2 h to obtain a solution of crystal nuclei with a D50 of 0.8 μm;
(3)晶种合成:在100L反应釜中加水至淹没桨叶,加入含1kg、D50为0.8μm的晶核的溶液作为底液,加入碳酸钠调节pH至8.5,反应釜的搅拌桨转速调至1000r/min,反应温度控制在35℃,用精确计量泵同时向反应釜中并流加入步骤(1)中配制的金属盐溶液和沉淀剂溶液,并使反应液的pH保持在8.0~8.5,反应釜溢流出的浆料通过浓缩机提浓、固液分离后的固相返回到反应釜,循环往复,反应过程中不断取样测试粒度,当检测到反应釜内物料的D50达到2.5μm时,停止进料,并继续搅拌陈化2小时后放置于带搅拌的储罐存放;(3) Seed synthesis: water was added to a 100L reactor until the blades were submerged, a solution containing 1kg of crystal nuclei with a D50 of 0.8μm was added as the bottom solution, sodium carbonate was added to adjust the pH to 8.5, the speed of the stirring blade of the reactor was adjusted to 1000r/min, the reaction temperature was controlled at 35°C, the metal salt solution and the precipitant solution prepared in step (1) were added to the reactor simultaneously by a precise metering pump, and the pH of the reaction solution was maintained at 8.0-8.5, the slurry overflowing from the reactor was concentrated by a concentrator, and the solid phase after solid-liquid separation was returned to the reactor, and the cycle was repeated. During the reaction process, samples were continuously taken to test the particle size. When the D50 of the material in the reactor was detected to reach 2.5μm, the feeding was stopped, and the stirring and aging was continued for 2 hours before being placed in a storage tank with stirring for storage;
(4)连续法生长:向干净的连续法反应釜加水至溢流口,将反应釜搅拌转速调整到800r/min,反应温度调整到60℃,加入碳酸钠调节母液的pH为8.5,继续用精密计量泵将步骤(1)中配好的金属盐溶液和沉淀剂溶液并流加入到反应釜中,调整沉淀剂溶液的流量,控制反应溶液的pH为8.0~8.5,同时用蠕动泵将步骤(3)中合成的晶种浆料连续进入反应釜,通过调节晶种浆料流量控制反应釜内物料粒度,每间隔2小时取样检测粒度稳定在6.0±0.3μm,径距稳定在1.1~1.4,电镜球形度较好时,收集溢流料;(4) Continuous growth: add water to the overflow port of a clean continuous reactor, adjust the stirring speed of the reactor to 800 r/min, adjust the reaction temperature to 60° C., add sodium carbonate to adjust the pH of the mother liquor to 8.5, continue to use a precision metering pump to add the metal salt solution and the precipitant solution prepared in step (1) to the reactor in parallel, adjust the flow rate of the precipitant solution, and control the pH of the reaction solution to 8.0-8.5. At the same time, use a peristaltic pump to continuously feed the seed slurry synthesized in step (3) into the reactor, and control the particle size of the material in the reactor by adjusting the flow rate of the seed slurry. Take samples every 2 hours to detect that the particle size is stable at 6.0±0.3 μm, and the diameter distance is stable at 1.1-1.4. When the sphericity under an electron microscope is good, collect the overflow material;
(5)将收集的物料用纯水多次洗涤固体物料,然后干燥、过筛,得到球形度好目标粒度6.0μm的富锰碳酸盐前驱体;(5) washing the collected solid material with pure water for multiple times, and then drying and sieving to obtain a manganese-rich carbonate precursor with good sphericity and a target particle size of 6.0 μm;
(6)将上述步骤(5)得到的富锰碳酸盐前驱体在回转炉中进行预烧,其中烧结制度为300℃预烧2h、400℃预烧2h、450℃预烧3h,预烧期间的升温速率均控制在2℃/min,从而得到本实施例的目标氧化物前驱体Ni0.32Mn0.66Co0.02Oz(CO3)m,其中镍、锰及掺杂元素钴的金属摩尔比可以通过ICP-AES检测确定。(6) The manganese-rich carbonate precursor obtained in the above step (5) is pre-fired in a rotary kiln, wherein the sintering conditions are pre-fired at 300°C for 2h, pre-fired at 400°C for 2h, and pre-fired at 450°C for 3h, and the heating rate during the pre-fired is controlled at 2°C/min, thereby obtaining the target oxide precursor Ni 0.32 Mn 0.66 Co 0.02 O z (CO 3 ) m of this embodiment, wherein the metal molar ratio of nickel, manganese and the doping element cobalt can be determined by ICP-AES detection.
实施例3:Embodiment 3:
一种本发明的富锰氧化物前驱体,该富锰氧化物前驱体由Ni0.30Mn0.70CO3前驱体分步烧结得到,含有镍的氧化物相和锰的氧化物相,该富锰氧化物前驱体的D50为12.1μm,径距span=(D90-D10)/D50控制在1.25。该富锰氧化物前驱体的FWHW(211)为0.42,富锰氧化物前驱体的BET为58.7m2/g。A manganese-rich oxide precursor of the present invention is obtained by step-by-step sintering of a Ni 0.30 Mn 0.70 CO 3 precursor, and contains a nickel oxide phase and a manganese oxide phase. The D50 of the manganese-rich oxide precursor is 12.1 μm, and the diameter span = (D90-D10)/D50 is controlled at 1.25. The FWHW (211) of the manganese-rich oxide precursor is 0.42, and the BET of the manganese-rich oxide precursor is 58.7 m 2 /g.
本实施例所述高球型度富锰氧化物前驱体的制备方法,包括如下步骤:The method for preparing the high-sphericity manganese-rich oxide precursor described in this embodiment comprises the following steps:
(1)采用硫酸镍、硫酸锰为原料,按镍、锰的摩尔比0.30:0.70配制总浓度为2mol/L的金属盐溶液,备用;采用碳酸氢钠为沉淀剂,配制1.8mol/L的沉淀剂溶液,备用;(1) using nickel sulfate and manganese sulfate as raw materials, preparing a metal salt solution with a total concentration of 2 mol/L according to a molar ratio of nickel to manganese of 0.30:0.70, and setting aside; using sodium bicarbonate as a precipitant, preparing a precipitant solution of 1.8 mol/L, and setting aside;
(2)晶核制备:在100L反应釜中加水至淹没桨叶,加入碳酸氢钠调节pH至11.5,反应釜的搅拌桨转速调至900r/min,反应温度控制在40℃,用精确计量泵同时向反应釜中并流加入步骤(1)中配制的金属盐溶液和沉淀剂溶液,并使反应液的pH保持在11.9-12.1,反应3h得到D50为1.2μm的晶核; (2) Preparation of crystal nuclei: water was added to a 100 L reactor until the blades were submerged, sodium bicarbonate was added to adjust the pH to 11.5, the speed of the stirring blade of the reactor was adjusted to 900 r/min, the reaction temperature was controlled at 40° C., the metal salt solution and the precipitant solution prepared in step (1) were simultaneously added to the reactor in parallel using a precise metering pump, and the pH of the reaction solution was maintained at 11.9-12.1. The reaction was continued for 3 h to obtain crystal nuclei with a D50 of 1.2 μm;
(3)晶种合成:在100L反应釜中加水至淹没桨叶,加入含0.8kg、D50为1.2μm的晶核的溶液作为底液,加入碳酸氢钠调节pH至8.5,反应釜的搅拌桨转速调至900r/min,反应温度控制在40℃,用精确计量泵同时向反应釜中并流加入步骤(1)中配制的金属盐溶液和沉淀剂溶液,并使反应液的pH保持在8.0~8.5,反应釜溢流出的浆料通过浓缩机提浓、固液分离后的固相返回到反应釜,循环往复,反应过程中不断取样测试粒度,当检测到反应釜内物料的D50达到4.0μm时,停止进料,并继续搅拌陈化2小时后放置于带搅拌的储罐存放;(3) Seed synthesis: water was added to a 100L reactor until the blades were submerged, a solution containing 0.8kg of crystal nuclei with a D50 of 1.2μm was added as the bottom solution, sodium bicarbonate was added to adjust the pH to 8.5, the speed of the stirring blade of the reactor was adjusted to 900r/min, the reaction temperature was controlled at 40°C, the metal salt solution and the precipitant solution prepared in step (1) were added to the reactor simultaneously by a precise metering pump, and the pH of the reaction solution was maintained at 8.0-8.5, the slurry overflowing from the reactor was concentrated by a concentrator, and the solid phase after solid-liquid separation was returned to the reactor, and the cycle was repeated. During the reaction, samples were continuously taken to test the particle size. When the D50 of the material in the reactor was detected to reach 4.0μm, the feeding was stopped, and the stirring and aging was continued for 2 hours before being placed in a storage tank with stirring for storage;
(4)连续法生长:向干净的连续法反应釜加水至溢流口,将反应釜搅拌转速调整到900r/min,反应温度调整到60℃,加入碳酸氢钠调节母液的pH为8.5,继续用精密计量泵将步骤(1)中配好的金属盐溶液和沉淀剂溶液并流加入到反应釜中,调整沉淀剂溶液的流量,控制反应溶液的pH为8.5~9.0,同时用蠕动泵将步骤(3)中合成的晶种浆料连续进入反应釜,通过调节晶种浆料流量控制反应釜内物料粒度,每间隔2小时取样检测粒度稳定在12.0±0.5μm,径距稳定在1.1~1.4,电镜球形度较好时,收集溢流料;(4) Continuous growth: add water to the overflow port of a clean continuous reactor, adjust the stirring speed of the reactor to 900 r/min, adjust the reaction temperature to 60°C, add sodium bicarbonate to adjust the pH of the mother liquor to 8.5, continue to use a precision metering pump to add the metal salt solution and the precipitant solution prepared in step (1) to the reactor in parallel, adjust the flow rate of the precipitant solution, and control the pH of the reaction solution to 8.5-9.0. At the same time, use a peristaltic pump to continuously feed the seed slurry synthesized in step (3) into the reactor, and control the particle size of the material in the reactor by adjusting the flow rate of the seed slurry. Take samples every 2 hours to detect that the particle size is stable at 12.0±0.5 μm, and the diameter distance is stable at 1.1-1.4. When the sphericity under an electron microscope is good, collect the overflow material;
(5)将收集的物料用纯水多次洗涤固体物料,然后干燥、过筛,得到球形度好的12.1μm的富锰碳酸盐前驱体;(5) washing the collected solid material with pure water for multiple times, and then drying and sieving to obtain a manganese-rich carbonate precursor with good sphericity of 12.1 μm;
(6)将上述步骤(5)得到的富锰碳酸盐前驱体在回转炉中进行预烧,其中烧结制度为300℃预烧2h、400℃预烧3h、550℃预烧2h,预烧期间的升温速率均控制在1℃/min,从而得到本实施例的目标氧化物前驱体Ni0.30Mn0.70Oz(CO3)m,其中镍、锰的金属摩尔比可以通过ICP-AES检测确定。(6) The manganese-rich carbonate precursor obtained in the above step (5) is pre-fired in a rotary kiln, wherein the sintering conditions are pre-fired at 300°C for 2h, pre-fired at 400°C for 3h, and pre-fired at 550°C for 2h, and the heating rate during the pre-fired is controlled at 1°C/min, thereby obtaining the target oxide precursor Ni 0.30 Mn 0.70 O z (CO 3 ) m of this embodiment, wherein the metal molar ratio of nickel to manganese can be determined by ICP-AES detection.
对比例4:Comparative Example 4:
对比例4的具体实施方式、操作步骤及工艺参数条件与上述实施例3基本相同,其区别在于不实施实施例2中步骤(6)的过程,直接制备得到富锰碳酸盐前驱体。The specific implementation method, operation steps and process parameter conditions of Comparative Example 4 are basically the same as those of Example 3, except that the process of step (6) in Example 2 is not implemented, and a manganese-rich carbonate precursor is directly prepared.
实施例4:Embodiment 4:
一种本发明的富锰氧化物前驱体,该富锰氧化物前驱体由Ni0.40Mn0.60CO3前驱体分步烧结得到,含有镍的氧化物相和锰的氧化物相,该富锰氧化物前驱体的D50为8.2μm,径距span=(D90-D10)/D50控制在1.28。该富锰氧化物前驱体的FWHW(211)为0.38,富锰氧化物前驱体的BET为62.47m2/g。本实施例所述高球型度富锰氧化物前驱体的制备方法,包括如下步骤:A manganese-rich oxide precursor of the present invention is obtained by step-by-step sintering of a Ni 0.40 Mn 0.60 CO 3 precursor, and contains a nickel oxide phase and a manganese oxide phase. The D50 of the manganese-rich oxide precursor is 8.2 μm, and the diameter span = (D90-D10)/D50 is controlled at 1.28. The FWHW (211) of the manganese-rich oxide precursor is 0.38, and the BET of the manganese-rich oxide precursor is 62.47 m 2 /g. The preparation method of the high-sphericity manganese-rich oxide precursor described in this embodiment comprises the following steps:
(1)采用硫酸镍、硫酸锰为原料,按镍、锰的摩尔比0.4:0.6配制总浓度为2.2mol/L的金属盐溶液,备用;采用碳酸钠为沉淀剂,配制1.8mol/L的沉淀剂溶液,备用;(1) using nickel sulfate and manganese sulfate as raw materials, preparing a metal salt solution with a total concentration of 2.2 mol/L according to a molar ratio of nickel to manganese of 0.4:0.6, and setting aside; using sodium carbonate as a precipitant, preparing a precipitant solution of 1.8 mol/L, and setting aside;
(2)晶核制备:在100L反应釜中加水至淹没桨叶,加入碳酸钠调节pH至12,反应釜 的搅拌桨转速调至1000r/min,反应温度控制在45℃,用精确计量泵同时向反应釜中并流加入步骤(1)中配制的金属盐溶液和沉淀剂溶液,并使反应液的pH保持在11.9-12.1,反应3h得到D50为1.0μm的晶核;(2) Crystal nucleus preparation: Add water to a 100 L reactor until the blades are submerged, add sodium carbonate to adjust the pH to 12, and The stirring blade speed is adjusted to 1000 r/min, the reaction temperature is controlled at 45° C. The metal salt solution and the precipitant solution prepared in step (1) are added to the reactor in parallel by a precise metering pump, and the pH of the reaction solution is maintained at 11.9-12.1. The reaction is continued for 3 h to obtain crystal nuclei with a D50 of 1.0 μm;
(3)晶种合成:在100L反应釜中加水至淹没桨叶,加入含1.0kg、D50为1.0μm的晶核的溶液作为底液,加入碳酸钠调节pH至8.5,反应釜的搅拌桨转速调至800r/min,反应温度控制在45℃,用精确计量泵同时向反应釜中并流加入步骤(1)中配制的金属盐溶液和沉淀剂溶液,并使反应液的pH保持在8.0~8.5,反应釜溢流出的浆料通过浓缩机提浓、固液分离后的固相返回到反应釜,循环往复,反应过程中不断取样测试粒度,当检测到反应釜内物料的D50达到3.0μm时,停止进料,并继续搅拌陈化2小时后放置于带搅拌的储罐存放;(3) Seed synthesis: water was added to a 100L reactor until the blades were submerged, a solution containing 1.0kg of crystal nuclei with a D50 of 1.0μm was added as the bottom solution, sodium carbonate was added to adjust the pH to 8.5, the stirring blade speed of the reactor was adjusted to 800r/min, the reaction temperature was controlled at 45°C, the metal salt solution and the precipitant solution prepared in step (1) were added to the reactor in parallel by a precise metering pump, and the pH of the reaction solution was maintained at 8.0-8.5, the slurry overflowing from the reactor was concentrated by a concentrator, and the solid phase after solid-liquid separation was returned to the reactor, and the cycle was repeated. During the reaction, samples were continuously taken to test the particle size. When the D50 of the material in the reactor was detected to reach 3.0μm, the feeding was stopped, and the stirring and aging was continued for 2 hours before being placed in a storage tank with stirring for storage;
(4)连续法生长:向干净的连续法反应釜加水至溢流口,将反应釜搅拌转速调整到900r/min,反应温度调整到60℃,加入碳酸钠调节母液的pH为8.5,继续用精密计量泵将步骤(1)中配好的金属盐溶液和沉淀剂溶液并流加入到反应釜中,调整沉淀剂溶液的流量,控制反应溶液的pH为8.3-8.7,同时用蠕动泵将步骤(3)中合成的晶种浆料连续进入反应釜,通过调节晶种浆料流量控制反应釜内物料粒度,每间隔2小时取样检测粒度稳定在8.0±0.3μm,径距稳定在1.1~1.4,电镜球形度较好时,收集溢流料;(4) Continuous growth: add water to the overflow port of a clean continuous reactor, adjust the stirring speed of the reactor to 900 r/min, adjust the reaction temperature to 60°C, add sodium carbonate to adjust the pH of the mother liquor to 8.5, continue to use a precision metering pump to add the metal salt solution and the precipitant solution prepared in step (1) to the reactor in parallel, adjust the flow rate of the precipitant solution, and control the pH of the reaction solution to 8.3-8.7. At the same time, use a peristaltic pump to continuously feed the seed slurry synthesized in step (3) into the reactor, and control the particle size of the material in the reactor by adjusting the flow rate of the seed slurry. Take samples every 2 hours to detect that the particle size is stable at 8.0±0.3 μm, and the diameter distance is stable at 1.1-1.4. When the sphericity under the electron microscope is good, collect the overflow material;
(5)将收集的物料用纯水多次洗涤固体物料,然后干燥、过筛,得到球形度好8.2μm的富锰碳酸盐前驱体;(5) washing the collected solid material with pure water for multiple times, and then drying and sieving to obtain a manganese-rich carbonate precursor with a sphericity of 8.2 μm;
(6)将上述步骤(5)得到的富锰碳酸盐前驱体在回转炉中进行预烧,其中烧结制度为200℃预烧2h、400℃预烧1h、500℃预烧3h,预烧期间的升温速率均控制在3℃/min,从而得到本实施例的目标氧化物前驱体Ni0.40Mn0.60Oz(CO3)m(6) The manganese-rich carbonate precursor obtained in the above step (5) is pre-fired in a rotary kiln, wherein the sintering conditions are 200°C for 2h, 400°C for 1h, and 500°C for 3h, and the heating rate during the pre-fire is controlled at 3°C/min, thereby obtaining the target oxide precursor Ni 0.40 Mn 0.60 O z (CO 3 ) m of this embodiment.
对比例5:Comparative Example 5:
对比例5的具体实施方式、操作步骤及工艺参数条件与上述实施例4基本相同,其区别在于不实施实施例4中步骤(6)的过程,直接制备得到富锰碳酸盐前驱体。The specific implementation method, operation steps and process parameter conditions of Comparative Example 5 are basically the same as those of Example 4, except that the process of step (6) in Example 4 is not implemented, and a manganese-rich carbonate precursor is directly prepared.
应用实施例:Application examples:
将上述本发明实施例1、3和4以及对比例2、3、4、5制备的富锂锰基正极材料,与炭黑、PVDF混合均匀、涂在铝箔上制成正极片,在真空手套箱中与锂金属片、隔膜、电解液组装成CR2025扣式电池,通过电化学性能测试仪测试,在2.0-4.7V的充放电限制电压下,以0.1C倍率测试放电容量,然后在0.33C下进行50周循环测试容量保持率,充放电比容量及容量保持率见下表4。The lithium-rich manganese-based positive electrode materials prepared in Examples 1, 3 and 4 of the present invention and Comparative Examples 2, 3, 4 and 5 were uniformly mixed with carbon black and PVDF, and coated on aluminum foil to make positive electrode sheets, which were assembled into CR2025 button batteries with lithium metal sheets, diaphragms and electrolytes in a vacuum glove box. The batteries were tested by an electrochemical performance tester. The discharge capacity was tested at a rate of 0.1C under a charge and discharge limiting voltage of 2.0-4.7V, and the capacity retention rate was then tested at 0.33C for 50 cycles. The charge and discharge specific capacity and capacity retention rate are shown in Table 4 below.
表4:实施例和对比例的前驱体制备的正极材料电化学性能测试对比
Table 4: Comparison of electrochemical performance tests of positive electrode materials prepared from precursors of the examples and comparative examples
从表4中可以看出,通过分步预烧得到的氧化物前驱体烧结后的正极放电容量和循环容量保持率均高于碳酸盐前驱体,而对比例3因预烧出现分相,所制备得到的正极电化学性能最差。It can be seen from Table 4 that the discharge capacity and cycle capacity retention rate of the positive electrode after sintering of the oxide precursor obtained by step-by-step pre-calcination are higher than those of the carbonate precursor, while the positive electrode prepared in Comparative Example 3 has the worst electrochemical performance due to phase separation during pre-calcination.
综上,本发明制备的氧化物前驱体产品致密性好,内部裂纹少,最终得到的富锂锰正极材料产品BET均匀稳定,电性能优异,适合产业化。 In summary, the oxide precursor product prepared by the present invention has good density and few internal cracks, and the finally obtained lithium-rich manganese positive electrode material product has uniform and stable BET and excellent electrical properties, and is suitable for industrialization.

Claims (13)

  1. 一种富锰氧化物前驱体,所述富锰氧化物前驱体含有镍的氧化物相和锰的氧化物相,其特征在于,所述富锰氧化物前驱体的D50为4~13μm,径距span=(D90-D10)/D50控制在1.1~1.4,FWHW(211)为0.3~0.65,所述富锰氧化物前驱体的BET为30~70m2/g。A manganese-rich oxide precursor, comprising a nickel oxide phase and a manganese oxide phase, characterized in that the D50 of the manganese-rich oxide precursor is 4-13 μm, the diameter span=(D90-D10)/D50 is controlled at 1.1-1.4, the FWHW(211) is 0.3-0.65, and the BET of the manganese-rich oxide precursor is 30-70 m 2 /g.
  2. 根据权利要求1所述的富锰氧化物前驱体,其特征在于,所述富锰氧化物前驱体的化学式为NixMnyMe(1-x-y)Oz(CO3)m,且0<x≤0.5,0.5≤y<1,0<z<2,0<m<1,Me为掺杂元素Co、Mg、Al、Zr、W、Fe、Cu中的一种或多种。The manganese-rich oxide precursor according to claim 1 is characterized in that the chemical formula of the manganese-rich oxide precursor is Ni x Mn y Me (1-xy) O z (CO 3 ) m , and 0<x≤0.5, 0.5≤y<1, 0<z<2, 0<m<1, and Me is one or more of the doping elements Co, Mg, Al, Zr, W, Fe, and Cu.
  3. 根据权利要求1或2所述的富锰氧化物前驱体,其特征在于,所述富锰氧化物前驱体的XRD图中基本不存在NiMn2O4相峰。The manganese-rich oxide precursor according to claim 1 or 2, characterized in that there is substantially no NiMn 2 O 4 phase peak in the XRD diagram of the manganese-rich oxide precursor.
  4. 根据权利要求1或2所述的富锰氧化物前驱体,其特征在于,所述富锰氧化物前驱体的平均裂纹率为2%~10%;所述富锰氧化物前驱体是由碳酸盐前驱体分步预烧后获得;The manganese-rich oxide precursor according to claim 1 or 2, characterized in that the average crack rate of the manganese-rich oxide precursor is 2% to 10%; the manganese-rich oxide precursor is obtained by pre-sintering a carbonate precursor in steps;
    所述平均裂纹率通过以下方法测定:先对待测样品进行抛光,获得表面平滑的样品,再利用场发射扫描电子显微镜得到CP电镜图,通过统计多个不同视野区域下CP电镜里裂纹个数,将该单个视野下裂纹个数/总颗粒数记为单个裂纹率,再取平均值即为平均裂纹率。The average crack rate is determined by the following method: first, the sample to be tested is polished to obtain a sample with a smooth surface, and then a CP electron microscope image is obtained using a field emission scanning electron microscope. The number of cracks in the CP electron microscope under multiple different field of view areas is counted, and the number of cracks under the single field of view/total number of particles is recorded as the single crack rate, and the average value is taken as the average crack rate.
  5. 一种富锰氧化物前驱体的制备方法,其特征在于,包括以下步骤:A method for preparing a manganese-rich oxide precursor, characterized in that it comprises the following steps:
    (1)配制包括镍盐、锰盐的金属盐溶液,配制包含碳酸根离子的沉淀剂溶液,备用;(1) preparing a metal salt solution including a nickel salt and a manganese salt, and preparing a precipitant solution including carbonate ions, and setting them aside;
    (2)利用步骤(1)配制的金属盐溶液和沉淀剂溶液制备得到含晶核的溶液;(2) preparing a solution containing crystal nuclei using the metal salt solution and the precipitant solution prepared in step (1);
    (3)以步骤(2)得到的含晶核的溶液作为底液,将步骤(1)中配制的金属盐溶液和沉淀剂溶液加入反应釜中,控制反应温度及pH值,搅拌后采用浓缩机提浓,固液分离后的固相返回到反应釜,循环往复,待反应浆料粒度达到设定值后,停止进料,得到晶种浆料;(3) using the solution containing crystal nuclei obtained in step (2) as the base liquid, adding the metal salt solution and the precipitant solution prepared in step (1) into the reactor, controlling the reaction temperature and pH value, stirring and concentrating with a concentrator, returning the solid phase after solid-liquid separation to the reactor, repeating the cycle, and stopping feeding after the particle size of the reaction slurry reaches the set value to obtain a seed slurry;
    (4)再重新将步骤(1)中配制的金属盐溶液和沉淀剂溶液并流加入到反应釜中,控制反应温度及pH值,同时将步骤(3)中合成的晶种浆料连续加入反应釜中,通过调节晶种浆料流量控制反应釜内物料粒度,直至达到目标粒度后,收集溢流料;(4) adding the metal salt solution and the precipitant solution prepared in step (1) into the reactor in parallel, controlling the reaction temperature and pH value, and continuously adding the seed slurry synthesized in step (3) into the reactor, controlling the particle size of the material in the reactor by adjusting the flow rate of the seed slurry, until the target particle size is reached, and collecting the overflow material;
    (5)将收集的溢流料进行固液分离,所得固相经洗涤干燥后得到碳酸盐前驱体;(5) separating the collected overflow material into solid and liquid, and washing and drying the obtained solid phase to obtain a carbonate precursor;
    (6)将步骤(5)得到的碳酸盐前驱体在空气气氛下经过预烧得到氧化物前驱体。(6) Pre-calcining the carbonate precursor obtained in step (5) in an air atmosphere to obtain an oxide precursor.
  6. 根据权利要求5所述的制备方法,其特征在于,步骤(1)中,所述镍盐选自硫酸镍、氯化镍、硝酸镍及乙酸镍中的一种或者几种;所述锰盐选自硫酸锰、氯化锰、硝酸锰及乙酸锰中的一种或几种;所述沉淀剂溶液选自碳酸钠溶液、碳酸氢钠溶液、碳酸钾溶液、碳酸氢钾溶液中的一种或几种,所述金属盐溶液中还含有Me盐,配制的金属盐总浓度为0.5~3mol/L,配制沉淀剂浓度为0.5~3mol/L。The preparation method according to claim 5 is characterized in that in step (1), the nickel salt is selected from one or more of nickel sulfate, nickel chloride, nickel nitrate and nickel acetate; the manganese salt is selected from one or more of manganese sulfate, manganese chloride, manganese nitrate and manganese acetate; the precipitant solution is selected from one or more of sodium carbonate solution, sodium bicarbonate solution, potassium carbonate solution and potassium bicarbonate solution, the metal salt solution further contains Me salt, the total concentration of the prepared metal salt is 0.5 to 3 mol/L, and the concentration of the prepared precipitant is 0.5 to 3 mol/L.
  7. 根据权利要求5所述的制备方法,其特征在于,步骤(2)中,在搅拌条件且常温控制下,用精确计量泵同时向反应釜中并流加入配制的金属盐溶液和沉淀剂溶液,并使反应液 的pH保持在11~13以制备晶核,所述晶核的粒度D50为0.5~1.5μm。The preparation method according to claim 5 is characterized in that in step (2), under stirring conditions and under normal temperature control, the prepared metal salt solution and the precipitant solution are simultaneously added to the reaction kettle by a precise metering pump, and the reaction solution is The pH of the solution is maintained at 11 to 13 to prepare crystal nuclei, wherein the particle size D50 of the crystal nuclei is 0.5 to 1.5 μm.
  8. 根据权利要求5所述的制备方法,其特征在于,步骤(4)中,所述晶种的目标粒度控制其D50为所述碳酸盐前驱体粒度的1/3~1/2。The preparation method according to claim 5 is characterized in that in step (4), the target particle size of the seed crystal is controlled so that its D50 is 1/3 to 1/2 of the particle size of the carbonate precursor.
  9. 根据权利要求5~8中任一项所述的制备方法,其特征在于,步骤(3)中,所述反应温度控制在25℃~55℃,反应的pH值为7.5~9.0,搅拌的速率控制为500~1000rpm/min。The preparation method according to any one of claims 5 to 8, characterized in that in step (3), the reaction temperature is controlled at 25°C to 55°C, the pH value of the reaction is 7.5 to 9.0, and the stirring rate is controlled at 500 to 1000 rpm/min.
  10. 根据权利要求5~8中任一项所述的制备方法,其特征在于,步骤(4)中,所述反应温度控制在40℃~70℃,反应的pH值为7.5~9.0。The preparation method according to any one of claims 5 to 8, characterized in that in step (4), the reaction temperature is controlled at 40° C. to 70° C., and the pH value of the reaction is 7.5 to 9.0.
  11. 根据权利要求5~8中任一项所述的制备方法,其特征在于,步骤(6)中,所述预烧至少分三步进行,预烧的温度为200℃~600℃,时间为2~8h。The preparation method according to any one of claims 5 to 8, characterized in that in step (6), the pre-calcination is carried out in at least three steps, the pre-calcination temperature is 200° C. to 600° C., and the time is 2 to 8 hours.
  12. 根据权利要求11所述的制备方法,其特征在于,所述分步预烧具体包括:先在200℃~300℃烧结1~2h,然后以1~5℃/min的升温速率升温到300℃~400℃烧结1~3h,再以1-5℃/min的升温速率升温到450℃~600℃烧结1~3h。The preparation method according to claim 11 is characterized in that the step-by-step pre-sintering specifically includes: first sintering at 200°C to 300°C for 1 to 2 hours, then heating to 300°C to 400°C at a heating rate of 1 to 5°C/min and sintering for 1 to 3 hours, and then heating to 450°C to 600°C at a heating rate of 1-5°C/min and sintering for 1 to 3 hours.
  13. 一种如权利要求1~4中任一项所述的富锰氧化物前驱体在制备锂离子电池富锂锰基正极材料中的应用。 A use of a manganese-rich oxide precursor as claimed in any one of claims 1 to 4 in the preparation of a lithium-rich manganese-based positive electrode material for a lithium-ion battery.
PCT/CN2023/115997 2022-09-30 2023-08-31 Manganese-rich oxide precursor, preparation method therefor, and use thereof WO2024066892A1 (en)

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