CN116675264A - Nickel-manganese binary precursor, preparation method and application thereof, positive electrode material and lithium ion battery - Google Patents

Nickel-manganese binary precursor, preparation method and application thereof, positive electrode material and lithium ion battery Download PDF

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CN116675264A
CN116675264A CN202310802539.8A CN202310802539A CN116675264A CN 116675264 A CN116675264 A CN 116675264A CN 202310802539 A CN202310802539 A CN 202310802539A CN 116675264 A CN116675264 A CN 116675264A
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equal
precursor
ltoreq
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positive electrode
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王聪
田鑫民
姚倩芳
张朋立
刘亚飞
陈彦彬
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BGRIMM Technology Group Co Ltd
Beijing Easpring Material Technology Co Ltd
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BGRIMM Technology Group Co Ltd
Beijing Easpring Material Technology Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/006—Compounds containing, besides nickel, two or more other elements, with the exception of oxygen or hydrogen
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/40—Nickelates
    • C01G53/42—Nickelates containing alkali metals, e.g. LiNiO2
    • C01G53/44—Nickelates containing alkali metals, e.g. LiNiO2 containing manganese
    • C01G53/50—Nickelates containing alkali metals, e.g. LiNiO2 containing manganese of the type [MnO2]n-, e.g. Li(NixMn1-x)O2, Li(MyNixMn1-x-y)O2
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
    • C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
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    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
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    • C01P2004/50—Agglomerated particles
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    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/11—Powder tap density
    • C—CHEMISTRY; METALLURGY
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    • C01P2006/00—Physical properties of inorganic compounds
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    • Y—GENERAL 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to a nickel-manganese binary precursor, a preparation method and application thereof, a positive electrode material and a lithium ion battery. The precursor has the composition shown in the formula I, ni x Mn y M z (OH) 2 (I) X is more than or equal to 0.8 and less than 1, y is more than or equal to 0 and less than or equal to 0.2, z is more than or equal to 0 and less than or equal to 0.1, x+y+z=1, and M is selected from at least one non-Co element; in powder X-ray diffraction measurement of the precursor by adopting CuK alpha rays, 2 theta has a characteristic double peak of a 001 crystal face within a range of 19+/-1.5 degrees. The precursor provided by the invention hasXRD diffraction {001} double peaks, and further improve the particle crystallinity, so that the positive electrode material has higher tap density on the premise of meeting the structural stability, and the capacity, the multiplying power performance and the cycle performance of the battery are improved.

Description

Nickel-manganese binary precursor, preparation method and application thereof, positive electrode material and lithium ion battery
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a nickel-manganese binary precursor, a preparation method and application thereof, a positive electrode material containing the nickel-manganese binary precursor, and a lithium ion battery containing the positive electrode material.
Background
The high nickel material has high energy density and obvious defects, particles on the surface are easy to generate irreversible phase change, and the structural stability and the high-temperature stability are poor; in addition, in recent years, the cobalt price is increased, so that the cost of the nickel-cobalt-manganese ternary material is greatly increased, in order to reduce the cost, the low cobalt and cobalt removal of the ternary material become research trends, however, the cobalt element mainly plays a role in improving the conductivity and the structural stability of crystals in the ternary material, so that the performance and the importance of the cobalt-free binary material are optimized.
The index of the precursor has a decisive influence on the basic properties of the positive electrode material, and the shape of the high-nickel electrode material microsphere has a great influence on the tap density of the high-nickel electrode material microsphere, and the contact between the positive electrode material and electrolyte is also influenced, so that the side reaction of the positive electrode material in the charge-discharge process is influenced, and the material performance is influenced. The particle morphology of the precursor is determined by the morphology and arrangement mode of the primary fibers, the current method for preparing the precursor mainly comprises coprecipitation, and parameters such as protective gas or oxidizing gas, pH value regulation, temperature, complexing agent concentration, liquid inlet speed, stirring rotation speed and the like are controlled in the process, so that the morphology and arrangement mode of the primary fibers are effectively controlled, and the aim of controlling the morphology of the precursor is fulfilled. However, the parameters have synergistic effect on the growth of primary fiber crystal planes With this, it is not easy to achieve the objective. The {001} crystal face of the ternary precursor is a low-energy face, and the {001} closed crystal face is oversized due to the fact that the crystal is easy to grow along the a axis and the b axis in the coprecipitation process, li + The transmission path becomes long, and thus the output performance is not exhibited.
Therefore, there is a need for a high nickel cobalt-free positive electrode material having a high capacity, high rate performance and high cycle performance.
Disclosure of Invention
The invention aims to overcome the technical problems and provide a nickel-manganese binary precursor, a preparation method thereof, a positive electrode material and a lithium ion battery, wherein the precursor has XRD diffraction {001} double peaks, the crystallinity of precursor particles is improved, and the capacity, the multiplying power performance, the cycle performance and the safety performance of the lithium ion battery are further improved.
In order to achieve the above object, a first aspect of the present invention provides a nickel manganese binary precursor having a composition represented by formula I, ni x Mn y M z (OH) 2 (I) X is more than or equal to 0.8 and less than 1, y is more than or equal to 0 and less than or equal to 0.2, z is more than or equal to 0 and less than or equal to 0.1, x+y+z=1, and M is selected from at least one non-Co element;
in powder X-ray diffraction measurement of the precursor by adopting CuK alpha rays, 2 theta has a characteristic double peak of a 001 crystal face within a range of 19+/-1.5 degrees.
In the present invention, the nickel-manganese binary precursor is simply referred to as a precursor unless otherwise specified.
Preferably, in powder X-ray diffraction measurement of the precursor by using cukα rays, the peak intensity ratio of the characteristic peak of the 101 crystal plane to the characteristic peak of the 001 crystal plane is as follows: i (101) /I (001) 1.5, wherein the characteristic peak 2 theta of the 101 crystal face is within the range of (37-41) °.
Preferably, the characteristic double peaks of the 001 crystal plane include a single peak a and a single peak B, and the single peak a is located at the left side of the single peak B.
Preferably, the peak intensities of the single peak a and single peak B satisfy: 500 is less than or equal to I (A) ≤2000，600≤I (B) ≤2000，0.35≤I (A)/ I (B) ≤2.4。
Preferably, the half-widths of the single peak a and the single peak B satisfy: FWHM of 0.4 DEG or less (A) ≤0.7°，0.4°≤FWHM (B) ≤0.6°，0.7≤FWHM (A) /FWHM (B) ≤1.5。
Preferably, the peak areas of the single peak a and the single peak B satisfy: 10000 is less than or equal to A (A) ≤70000，10000≤A (B) ≤75000，0.6≤A (A) /A (B) ≤2.2。
The second aspect of the invention provides a preparation method of a nickel-manganese binary precursor, which comprises the following steps: mixing the mixed salt solution, the complexing agent and the precipitator, performing coprecipitation reaction, regulating the oxygen content in the reaction system to be 0.5-10% by volume and the pH value to be 10-11.3, and sequentially washing and drying the obtained coprecipitation reaction product to obtain a precursor;
wherein the mixed salt solution is selected from an aqueous solution containing a nickel salt, a manganese salt, and optionally an M source, wherein M is selected from at least one non-Co element.
A third aspect of the present invention provides a precursor provided in the first aspect, or a precursor prepared by a preparation method provided in the second aspect, for use in a positive electrode material.
In a fourth aspect, the present invention provides a positive electrode material, which is prepared by sintering a precursor provided in the first aspect, or a precursor prepared by a preparation method provided in the second aspect.
Preferably, the positive electrode material is prepared by the following method: mixing the precursor, a lithium source and an M source and performing sintering in an oxygen-containing atmosphere when the precursor does not contain a doping element M to obtain the positive electrode material; or when the precursor contains doping element M, mixing the precursor with a lithium source and sintering to obtain the positive electrode material; wherein M in the M source is selected from at least one non-Co element.
In a fifth aspect, the present invention provides a lithium ion battery, which contains the positive electrode material provided in the fourth aspect.
Compared with the prior art, the invention has the following advantages:
(1) The precursor provided by the invention has characteristic double peaks of XRD diffraction 001 crystal face by limiting the precursor, so that the crystallinity of particles is improved, and especially by limiting I (101) /I (001) More than or equal to 1.5, the crystallinity of the precursor is further improved, so that the positive electrode material obtained by sintering the precursor has higher tap density on the premise of meeting the structural stability;
(2) According to the preparation method of the precursor, the technical means of coprecipitation is adopted, and the oxygen content in a reaction system is controlled to be 0.5-10% by volume and the pH value is controlled to be 10-11.3, so that the precursor generates XRD diffraction double peaks; meanwhile, the preparation method simplifies the process flow, has relatively low cost and is suitable for industrial production;
(3) The precursor provided by the invention is used for the lithium ion battery, and can effectively improve the capacity, the multiplying power performance and the capacity retention rate of the battery.
Drawings
FIG. 1 is an SEM image of a precursor S1 prepared according to example 1, wherein FIGS. 1a-1b are SEM images of primary particles of the precursor S1 and FIGS. 1c-1d are SEM images of secondary particles of the precursor S1;
FIG. 2 is an XRD pattern of precursor S1 prepared in example 1;
FIG. 3 is an SEM image of the precursor S2 prepared according to example 2, wherein FIGS. 3a-3b are SEM images of primary particles of the precursor S2 and FIGS. 3c-3d are SEM images of secondary particles of the precursor S2;
FIG. 4 is an XRD pattern of precursor S2 prepared in example 2;
FIG. 5 is an SEM image of the precursor S3 of example 3, wherein FIGS. 5a-5b are SEM images of primary particles of the precursor S3 and FIGS. 5c-5d are SEM images of secondary particles of the precursor S3;
FIG. 6 is an XRD pattern of precursor S3 prepared in example 3;
FIG. 7 is an SEM image of the precursor DS1 prepared according to comparative example 1, wherein FIGS. 7a-7b are SEM images of primary particles of the precursor DS1 and FIGS. 7c-7d are SEM images of secondary particles of the precursor DS 1;
fig. 8 is an XRD pattern of the precursor DS1 prepared in comparative example 1.
Detailed Description
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
The first aspect of the invention provides a nickel-manganese binary precursor, which has the composition shown in the formula I, ni x Mn y M z (OH) 2 (I) X is more than or equal to 0.8 and less than 1, y is more than or equal to 0 and less than or equal to 0.2, z is more than or equal to 0 and less than or equal to 0.1, x+y+z=1, and M is selected from at least one non-Co element;
in powder X-ray diffraction measurement of the precursor by adopting CuK alpha rays, 2 theta has a characteristic double peak of a 001 crystal face within a range of 19+/-1.5 degrees.
In the present invention, unless otherwise specified, the fact that M is selected from at least one non-Co element in formula I means that the precursor is a high nickel cobalt-free binary material, i.e., M is selected from other elements than Co.
In the present invention, without specifying that the precursor has a characteristic bimodality in which 2θ has a 001 crystal plane in the range of 19±1.5°, it means that the XRD peak of the 001 crystal plane of the precursor is split to bimodality, that is, split to a unimodal a on the left side and a unimodal B on the right side.
In some embodiments of the invention, in formula I, 0.8.ltoreq.x < 1,0 < y.ltoreq.0.2, 0.ltoreq.z.ltoreq.0.1, and x+y+z=1, m being selected from at least one non-Co element.
In some embodiments of the present invention, it is further preferred that in formula I, 0.85.ltoreq.x.ltoreq. 0.99,0.01.ltoreq.y.ltoreq. 0.15,0.001.ltoreq.z.ltoreq.0.1, and x+y+z=1, M is selected from at least one element of La, cr, mo, ca, fe, hf, ti, zn, Y, zr, si, W, nb, sm, V, mg, B, Y and Al.
In some embodiments of the present invention, more preferably, in formula I, 0.9.ltoreq.x.ltoreq. 0.98,0.02.ltoreq.y.ltoreq. 0.1,0.001.ltoreq.z.ltoreq.0.01, and x+y+z=1, M being selected from at least one element of La, cr, mo, hf, ti, zn, Y, zr, W, nb, V, mg, B, Y and Al.
In the invention, the tap density of the positive electrode material containing the precursor is further regulated by regulating and controlling the types of each metal element corner mark (x, y, z) and M element in the formula I, so that the electrochemical performance of the lithium ion battery is regulated and controlled.
In some embodiments of the present invention, preferably, in powder X-ray diffraction measurement of the precursor using cukα rays, a peak intensity ratio of a characteristic peak of 101 crystal plane to a characteristic peak of 001 crystal plane satisfies: i (101) /I (001) 1.5, e.g., 1.5, 1.8, 2/2.2, 2.5, 2.8, 3, and any value in the range of any two values, preferably satisfying: i is less than or equal to 1.5 (101) /I (001) And less than or equal to 3, wherein the characteristic peak 2 theta of the 101 crystal face is within the range of (37-41) °.
In the present invention, when I (101) /I (001) When the lithium-ion battery is in the above range, the precursor has high crystallinity, excessive dissolved lithium can be restrained after the precursor is sintered into the positive electrode material, particularly, gas generation caused by the reaction of electrolyte and excessive lithium can be restrained, and the structural stability during lithium deintercalation is improved, so that the lithium-ion battery can be a lithium composite oxide with less oxygen deficiency, the positive electrode material has high tap density, and a lithium ion battery containing the positive electrode material has high first charge-discharge capacity, first efficiency, rate capability and high capacity retention rate.
In some embodiments of the present invention, preferably, the 001 plane has a characteristic bimodal peak intensity I (101) 300 to 4000, preferably 500 to 3000; full width at half maximum FWHM (101) Is (0.5-2) °, preferably (0.6-1.8) °. In the invention, jade analysis shows that the cause of 001 crystal face splitting peak is nickel manganese oxide impurity phase of nickel hydroxide manganese crystal, manganese mainly plays a role in stabilizing structure, and the safety performance of the material is improved.
In some embodiments of the present invention, preferably, as shown in fig. 2, 4 and 6, the characteristic double peak of the 001 crystal plane includes a single peak a and a single peak B, and the single peak a is located at the left side of the single peak B.
In some embodiments of the present invention, preferably, the peak intensities of the single peak a and single peak B satisfy: 500 is less than or equal to I (A) ≤2000，600≤I (B) ≤2000，0.35≤I (A)/ I (B) ≤2.4。
In some embodiments of the present invention, preferably, the half-widths of the single peak a and single peak B satisfy: FWHM of 0.4 DEG or less (A) ≤0.7°，0.4°≤FWHM (B) ≤0.6°，0.7≤FWHM (A) /FWHM (B) ≤1.5。
In some embodiments of the present invention, preferably, the peak areas of the single peak a and single peak B satisfy: 10000 is less than or equal to A (A) ≤70000，10000≤A (B) ≤75000，0.6≤A (A) /A (B) ≤2.2。
In the present invention, by defining the peak intensities, half-peak widths, and peak areas of the single peaks a and B to satisfy the above ranges, the precursor is characterized by a large BET and tap density, and a narrow particle size distribution.
In some embodiments of the present invention, preferably, the precursor is a secondary particle composed of primary particles, the primary particles having a wedge structure; further preferably, the precursor has a spherical structure.
In some embodiments of the invention, preferably, the precursor has a BET of 3-25m 2 /g, e.g. 3m 2 /g、5m 2 /g、10m 2 /g、15m 2 /g、20m 2 /g、25m 2 G, and any value in the range of any two values, preferably 5-20m 2 /g; tap density is more than or equal to 1g/cm 3 For example, 1g/cm 3 、1.3g/cm 3 、1.5g/cm 3 、2g/cm 3 、2.5g/cm 3 And any value in the range of any two values, preferably 1.3-2.5g/cm 3 。
In some embodiments of the invention, preferably, the particle size distribution K of the precursor 90 The method meets the following conditions: k is more than or equal to 0.4 90 Less than or equal to 0.8, e.g., 0.4, 0.5, 0.6, 0.7, 0.8, and a range of any two numerical valuesArbitrary value in the circle, where K 90 ＝(D 90 -D 10 )/D 50 ，D 90 、D 10 And D 50 The particle sizes of the precursor in the particle size distribution are respectively 90%, 10% and 50%, and the unit is mu m.
In some embodiments of the invention, preferably, D of the precursor 50 Is 6-20 μm, preferably 8-14 μm.
The second aspect of the invention provides a preparation method of a nickel-manganese binary precursor, which comprises the following steps: mixing the mixed salt solution, the complexing agent and the precipitator, performing coprecipitation reaction, regulating the oxygen content in the reaction system to be 0.5-10% by volume and the pH value to be 10-11.3, and sequentially washing and drying the obtained coprecipitation reaction product to obtain a precursor;
Wherein the mixed salt solution is selected from an aqueous solution containing a nickel salt, a manganese salt, and optionally an M source, wherein M is selected from at least one non-Co element.
In the present invention, the precursor is made to produce XRD diffraction furcation bimodal by controlling the oxygen content in the reaction system to be any value in the range of 0.5 to 10% by volume, for example, 0.5% by volume, 1% by volume, 2% by volume, 5% by volume, 8% by volume, 10% by volume, and any two values. Preferably, the oxygen content in the reaction system is regulated to be 0.5-8 vol%. When the oxygen content is low, the precursor is in a hydroxide state, and the 001 peak does not have a splitting peak phenomenon; when the oxygen content is higher, the crystal is mostly composed of oxide, the primary fiber is thinner, the 001 peak has no splitting peak phenomenon, and the half-width is narrower.
In some embodiments of the present invention, preferably, when the complexing agent is selected from the group consisting of ammonium ion-containing compounds, the ammonia concentration in the reaction system is regulated to any value in the range of 1 to 12g/L, for example, 1g/L, 2g/L, 5g/L, 8g/L, 10g/L, 12g/L, and any two values, preferably 3 to 8g/L.
In some embodiments of the invention, preferably, the conditions of the coprecipitation reaction include: the temperature is 50-80 ℃, and the pH value is 10-11.3, preferably 10.3-11.1; the rotation speed is 250-750rpm.
In the invention, the particle size of the precursor is further regulated by regulating the time of the coprecipitation reaction. Along with the extension of the coprecipitation reaction time, the particles of the coprecipitation reaction product are gradually grown up, and the crystallinity is also continuously improved; and (3) testing the granularity of the slurry by using a laser granularity meter every 2 hours in the reaction process, and regulating the pH value in the reaction kettle to ensure that the pH value in the reaction kettle is kept within the range of (10-11.3) +/-0.1.
In some embodiments of the present invention, preferably, the nickel salt, manganese salt and M source satisfy n (Ni): n (Mn): n (M), 0.8.ltoreq.n (Ni) < 1,0 < n (Mn). Ltoreq.0.2, 0.ltoreq.n (M). Ltoreq.0.1, in terms of metal elements; further preferably, 0.85.ltoreq.n (Ni). Ltoreq. 0.99,0.01.ltoreq.n (Mn). Ltoreq. 0.15,0.001.ltoreq.n (M). Ltoreq.0.1; more preferably, 0.9.ltoreq.n (Ni). Ltoreq. 0.98,0.02.ltoreq.n (Mn). Ltoreq. 0.1,0.001.ltoreq.n (M). Ltoreq.0.01.
In some embodiments of the present invention, preferably, M in the M source is at least one element selected from La, cr, mo, ca, fe, hf, ti, zn, Y, zr, si, W, nb, sm, V, mg, B, Y and Al; further preferably, M in the M source is at least one element selected from La, cr, mo, hf, ti, zn, Y, zr, W, nb, V, mg, B, Y and Al.
In some embodiments of the invention, the nickel salt includes, but is not limited to, nickel sulfate, nickel nitrate, nickel chlorate, and the like; the manganese salt includes, but is not limited to, manganese sulfate, manganese nitrate, manganese chlorate, etc.; the M source includes, but is not limited to, at least one selected from the group consisting of oxides, sulfates, nitrates, chlorates containing M.
In a specific embodiment of the present invention, the M source is selected from at least one of an oxide, sulfate, nitrate, chlorate containing La, cr, mo, ca, fe, hf, ti, zn, Y, zr, si, W, nb, sm, V, mg, B, Y, al, preferably from at least one of an oxide, sulfate, nitrate, chlorate containing La, cr, mo, hf, ti, zn, Y, zr, W, nb, V, mg, B, Y, al.
In some embodiments of the present invention, preferably, the concentration of the mixed salt solution is 0.1 to 10mol/L in terms of metal element, and the nickel salt, manganese salt and M source satisfy n (Ni): n (Mn): n (M), 0.8.ltoreq.n (Ni) < 1,0 < n (Mn). Ltoreq.0.2, 0.ltoreq.n (M). Ltoreq.0.1; further preferably, 0.85.ltoreq.n (Ni). Ltoreq. 0.99,0.01.ltoreq.n (Mn). Ltoreq. 0.15,0.001.ltoreq.n (M). Ltoreq.0.1; more preferably, 0.9.ltoreq.n (Ni). Ltoreq. 0.98,0.02.ltoreq.n (Mn). Ltoreq. 0.1,0.001.ltoreq.n (M). Ltoreq.0.01.
In the invention, the particle size range of the precursor is regulated and controlled by controlling the flow rate of the feed liquid of the mixed salt. Preferably, the liquid inlet flow rate of the mixed metal salt is 50-300mL/min, preferably 150-250mL/min.
In one embodiment of the present invention, the precipitant includes, but is not limited to, sodium hydroxide and/or potassium hydroxide; the complexing agent includes, but is not limited to, aqueous ammonia and the like. In the invention, the precipitant and the complexing agent are both in the form of aqueous solutions, and the concentration of the aqueous precipitant solution and the concentration of the aqueous complexing agent solution are each independently 5-13.3mol/L.
In some embodiments of the invention, preferably, the washing process comprises: and (3) alternately performing alkali washing and water washing on the coprecipitation reaction product.
In one embodiment of the invention, the washing process comprises: performing alkali washing on the precipitation reaction product and alkali liquor to obtain an alkali washing product and deionized water to obtain a water washing product; repeating the operation for 1-5 times on the water washing product to obtain the precursor. In the present invention, the alkali liquor includes, but is not limited to, sodium hydroxide solution and/or potassium hydroxide solution at a concentration of 0.1 to 2 mol/L.
In some embodiments of the present invention, preferably, the drying conditions include: the temperature is 80-150 ℃ and the time is 2-6h.
A third aspect of the present invention provides a precursor provided in the first aspect, or a precursor prepared by a preparation method provided in the second aspect, for use in a positive electrode material.
In a fourth aspect, the present invention provides a positive electrode material, which is prepared by sintering a precursor provided in the first aspect, or a precursor prepared by a preparation method provided in the second aspect.
In the present invention, the use of the precursor for the positive electrode material can suppress excessive elution of lithium, particularly, can suppress gas generation caused by the reaction between the electrolyte and the excessive lithium, and can improve the structural stability at the time of deintercalation of lithium, thereby enabling the positive electrode material to be a lithium composite oxide with less oxygen deficiency, and the positive electrode material has a high tap density.
In some embodiments of the present invention, preferably, the positive electrode material is prepared by the following method: mixing the precursor, a lithium source and an M source and performing sintering in an oxygen-containing atmosphere when the precursor does not contain a doping element M to obtain the positive electrode material; or when the precursor contains doping element M, mixing the precursor with a lithium source and sintering to obtain the positive electrode material; wherein M in the M source is selected from at least one non-Co element.
In the present invention, the doping element M may be added in the preparation of the precursor or in the preparation of the positive electrode material. Preferably, when doping element M is added in preparing the precursor, said M source is selected from soluble compounds; when doping element M is added to the preparation of the positive electrode material, the M source is selected from oxides.
In one embodiment of the present invention, the lithium source includes, but is not limited to, lithium oxide, lithium hydroxide, and the like.
In some embodiments of the present invention, preferably, the lithium source is used in an amount ratio such that: 0.9.ltoreq.n (Li) ]/[ n (Ni) +n (Mn) +n (M) ]. Ltoreq.1.2, e.g., any of the values in the range of 0.9, 1, 1.01, 1.02, 1.05, 1.06, 1.1, 1.15, 1.2, and any two values, further preferably satisfying: 1.ltoreq.n (Li) ]/[ n (Ni) +n (Mn) +n (M) ]. Ltoreq.1.1, more preferably: and (2) n (Li) ]/[ n (Ni) +n (Mn) +n (M) ] less than or equal to 1.01 and less than or equal to 1.06.
In the present invention, the M source is defined according to the above description, and the present invention is not described herein in detail.
In some embodiments of the invention, preferably, the M source is used in an amount that satisfies: 0.ltoreq.n (M) ]/[ n (Ni) +n (Mn) +n (M) ]. Ltoreq.0.1, e.g., any of the values in the range of 0, 0.001, 0.002, 0.005, 0.008, 0.01, 0.05, 0.1, and any two values, further preferably satisfying: 0.001.ltoreq.n (M) ]/[ n (Ni) +n (Mn) +n (M) ].ltoreq.0.1, more preferably: and (2) n (M)/[ n (Ni) +n (Mn) +n (M) ] less than or equal to 0.001.
In some embodiments of the invention, preferably, M in the M source is at least one element selected from Al, fe, mg, B, ca, sr, ba, zr, ti, ce, Y, W, la, nb, ta, zn, co and Mo, preferably at least one element selected from La, cr, mo, hf, ti, zn, Y, zr, W, nb, V, mg, B, Y and Al.
In some embodiments of the invention, preferably, the oxygen content of the oxygen-containing atmosphere is greater than or equal to 80% by volume, preferably greater than or equal to 95% by volume.
In some embodiments of the present invention, preferably, the sintering conditions include: the temperature is 600-900 ℃, preferably 700-800 ℃; the time is 0.1-20h, preferably 0.1-15h; the heating rate is 1-20deg.C/min, preferably 1-5deg.C/min.
In some embodiments of the present invention, preferably, the positive electrode material has a composition represented by formula II, li 1+ a Ni α Mn β M γ O 2 (II)；
Wherein, -0.1 is more than or equal to a and less than or equal to 0.2,0.8 is more than or equal to alpha and less than 1,0 is more than or equal to beta and less than or equal to 0.2,0 is more than or equal to gamma and less than or equal to 0.1, and alpha+beta+gamma=1; m is at least one non-Co element.
In some embodiments of the present invention, it is further preferred that, in formula II, a is more than or equal to 0 and less than or equal to 0.1,0.85, alpha is more than or equal to 0.99,0.01, beta is more than or equal to 0.15,0.001, gamma is more than or equal to 0.1, and alpha+beta+gamma=1; m is at least one element selected from La, cr, mo, ca, fe, hf, ti, zn, Y, zr, si, W, nb, sm, V, mg, B, Y and Al.
In some embodiments of the present invention, more preferably, in formula II, 0.01. Ltoreq.a.ltoreq. 0.06,0.9. Ltoreq.α.ltoreq. 0.98,0.02. Ltoreq.β.ltoreq. 0.1,0.001. Ltoreq.γ.ltoreq.0.01, and α+β+γ=1; m is at least one element selected from La, cr, mo, hf, ti, zn, Y, zr, W, nb, V, mg, B, Y and Al.
In some embodiments of the present invention, preferably, the positive electrode material has a tap density of 2.5g/cm or more 3 For example, 2.5g/cm 3 、2.6g/cm 3 、2.7g/cm 3 、2.8g/cm 3 、2.9g/cm 3 、3g/cm 3 And any value in the range of any two values, preferably 2.5-3g/cm 3 。
In some embodiments of the present invention, preferably, the positive electrode material has a layered structure.
In a fifth aspect, the present invention provides a lithium ion battery, which contains the positive electrode material provided in the fourth aspect.
The present invention will be described in detail by examples.
The process parameters for preparing the precursor and the cathode material of the examples and the comparative examples are shown in Table 1, and the physical parameters for preparing the precursor and the cathode material of the examples and the comparative examples are shown in Table 2.
Example 1
(1) Calculated by metal element, niSO 4 ·6H 2 O、MnSO 4 ·H 2 O is dissolved in water in a mol ratio of 95:5 to prepare a mixed salt solution with the concentration of 2 mol/L; preparing 8mol/L sodium hydroxide solution as a precipitator, and preparing 10mol/L ammonia water as a complexing agent;
(2) Adding deionized water into a 5L reaction kettle, wherein the temperature of the reaction kettle is controlled at 65 ℃ and the stirring rotating speed is set at 770rpm; adding the ammonia water and the sodium hydroxide solution into a reaction kettle to adjust the bottom solution, so that the ammonia concentration in the reaction kettle is adjusted to 3g/L, the pH value is adjusted to 11, nitrogen is introduced into the reaction kettle, the flow rate of the nitrogen is 20L/h, and the oxygen content in the reaction kettle is 5% by volume;
(3) Adding the mixed salt solution, the sodium hydroxide aqueous solution and the ammonia water into a reaction kettle through a metering pump, wherein the flow rate of the mixed salt solution is set to be 190mL/h, the flow rates of the sodium hydroxide solution and the ammonia water are automatically regulated according to the pH value and the ammonia concentration, performing coprecipitation reaction, testing the granularity of the slurry by a laser granularity meter every 2h in the reaction process, and regulating the pH value in the reaction kettle to ensure that the pH value in the reaction kettle is kept within a range of 11+/-0.1;
(4) To be of particle size D 50 Stopping after the growth of 14 mu mFeeding liquid, alternately washing the obtained coprecipitation reaction product with 0.2mol/L sodium hydroxide solution and water at 75 ℃, and drying at 120 ℃ for 3 hours to obtain the compound with the general formula of Ni 0.95 Mn 0.05 (OH) 2 Precursor S1 of (2);
(5) The precursor S1, a lithium source (lithium hydroxide) and an M source (TiO) were mixed in an oxygen-containing atmosphere (oxygen content: 95 vol.%) 2 ) Mixing, heating to 800 ℃ at 3 ℃/min, sintering for 12 hours, and cooling to room temperature to obtain the compound of the general formula Li 1.02 Ni 0.945 Mn 0.05 Ti 0.005 O 2 Positive electrode material P1 of (a);
wherein, the dosage ratio of the lithium source satisfies: [ n (Li) ]/[ n (Ni) +n (Mn) +n (M) ]=1.02. The amount of M source is as follows: [ n (M) ]/[ n (Ni) +n (Mn) +n (M) ]=0.005.
As shown in fig. 1, the SEM image of the precursor S1 is that the precursor S1 is a secondary particle composed of primary particles, the primary particles are in an elongated wedge-shaped structure, and the secondary particles have a spherical structure;
as shown in fig. 2, the XRD pattern of the precursor S1 shows that the precursor S1 has a characteristic bimodal of 001 crystal planes in the range of 2θ=18.7±1.5° as shown in fig. 2.
Example 2
(1) Calculated by metal element, niSO 4 ·6H 2 O、MnSO 4 ·H 2 O is dissolved in water according to the mol ratio of 90:10 to prepare 1.5mol/L mixed salt solution; preparing 4mol/L sodium hydroxide solution as a precipitator, and preparing 10mol/L ammonia water as a complexing agent;
(2) Adding deionized water into a 5L reaction kettle, wherein the temperature of the reaction kettle is controlled at 55 ℃ and the stirring rotating speed is set at 500rpm; adding the ammonia water and the sodium hydroxide solution into a reaction kettle to adjust the base solution, so that the ammonia concentration in the reaction kettle is adjusted to 7g/L, the pH value is adjusted to 10.8, nitrogen is introduced into the reaction kettle, the flow rate of the nitrogen is 100L/h, and the oxygen content in the reaction kettle is 0.5 volume percent;
(3) Adding the mixed salt solution, the sodium hydroxide aqueous solution and the ammonia water into a reaction kettle through a metering pump, wherein the flow rate of the mixed salt solution is set to be 100mL/h, the flow rates of the sodium hydroxide solution and the ammonia water are automatically adjusted according to the pH value and the ammonia concentration, performing coprecipitation reaction, testing the granularity of the slurry by a laser granularity meter every 2h in the reaction process, and keeping the pH value in the reaction kettle within a range of 10.8+/-0.1 by adjusting the pH value in the reaction kettle;
(4) To be of particle size D 50 Stopping feeding liquid after reaching 10 μm, alternately washing the obtained coprecipitation reaction product with 75 ℃ 0.2mol/L sodium hydroxide solution and water, and drying at 120 ℃ for 3 hours to obtain Ni with the general formula 0.9 Mn 0.1 (OH) 2 Precursor S2 of (2);
(5) The precursor S2, a lithium source (lithium hydroxide) and an M source (TiO) were mixed in an oxygen-containing atmosphere (oxygen content: 95 vol.%) 2 ) Mixing, heating to 800 ℃ at 3 ℃/min, sintering for 12 hours, and cooling to room temperature to obtain the compound of the general formula Li 1.02 Ni 0.896 Mn 0.099 Ti 0.005 O 2 Positive electrode material P1 of (a);
wherein, the dosage ratio of the lithium source satisfies: [ n (Li) ]/[ n (Ni) +n (Mn) +n (M) ]=1.02. The amount of M source is as follows: [ n (M) ]/[ n (Ni) +n (Mn) +n (M) ]=0.005.
As shown in fig. 3, the SEM image of the precursor S2 is that the precursor S2 is a secondary particle composed of primary particles, the primary particles are in an elongated wedge-shaped structure, and the secondary particles have a spherical structure;
As shown in fig. 4, the XRD pattern of the precursor S2 shows that the precursor S2 has a characteristic double peak of 001 crystal planes in the range of 2θ=19.5±1° from fig. 4.
Example 3
(1) Calculated by metal element, niSO 4 ·6H 2 O、MnSO 4 ·H 2 O is dissolved in water according to the mol ratio of 98:2 to prepare 1.5mol/L mixed salt solution; preparing 8mol/L sodium hydroxide solution as a precipitator, and preparing 5mol/L ammonia water as a complexing agent;
(2) Adding deionized water into a 5L reaction kettle, wherein the deionized water is not passed through an upper stirring paddle, controlling the temperature of the reaction kettle at 75 ℃, and setting the stirring rotating speed at 700rpm; adding the ammonia water and the sodium hydroxide solution into a reaction kettle to adjust the bottom solution, so that the ammonia concentration in the reaction kettle is adjusted to 11g/L, the pH value is adjusted to 10.3, nitrogen is introduced into the reaction kettle, the flow rate of the nitrogen is 10L/h, and the oxygen content in the reaction kettle is 8% by volume;
(3) Adding the mixed salt solution, the sodium hydroxide aqueous solution and the ammonia water into a reaction kettle through a metering pump, wherein the flow rate of the mixed salt solution is set to 240mL/h, the flow rates of the sodium hydroxide solution and the ammonia water are automatically adjusted according to the pH value and the ammonia concentration, performing coprecipitation reaction, testing the granularity of the slurry by a laser granularity meter every 2h in the reaction process, and keeping the pH value in the reaction kettle within a range of 10.3+/-0.1 by adjusting the pH value in the reaction kettle;
(4) To be of particle size D 50 Stopping feeding liquid after reaching 12 μm, alternately washing the obtained coprecipitation reaction product with 75 ℃ 0.2mol/L sodium hydroxide solution and water, and drying at 120 ℃ for 3 hours to obtain the catalyst with the general formula of Ni 0.98 Mn 0.02 (OH) 2 Precursor S3 of (2);
(5) The precursor S3, a lithium source (lithium hydroxide) and an M source (TiO) were mixed in an oxygen-containing atmosphere (oxygen content: 95 vol.%) 2 ) Mixing, heating to 800 ℃ at 3 ℃/min, sintering for 12 hours, and cooling to room temperature to obtain the compound of the general formula Li 1.02 Ni 0.975 Mn 0.02 Ti 0.005 O 2 Positive electrode material P3 of (a);
wherein, the dosage ratio of the lithium source satisfies: [ n (Li) ]/[ n (Ni) +n (Mn) +n (M) ]=1.02. The amount of M source is as follows: [ n (M) ]/[ n (Ni) +n (Mn) +n (M) ]=0.005.
As shown in fig. 5, the SEM image of the precursor S3 is that the precursor S3 is a secondary particle composed of primary particles, the primary particles are in a slender wedge-shaped structure, and the secondary particles have a spherical structure;
as shown in fig. 6, the XRD pattern of the precursor S3 shows that the precursor S3 has a characteristic double peak of 001 crystal planes in the range of 2θ=19.4±1° from fig. 6.
Example 4
(1) Calculated by metal element, niSO 4 ·6H 2 O、MnSO 4 ·H 2 O is dissolved in water according to the mol ratio of 95:5 to prepare 1.5mol/L mixed salt solution; preparing 8mol/L sodium hydroxide solutionAs a precipitator, 5mol/L ammonia water is prepared as a complexing agent;
(2) Adding deionized water into a 5L reaction kettle, wherein the deionized water is not passed through an upper stirring paddle, controlling the temperature of the reaction kettle at 75 ℃, and setting the stirring rotating speed at 700rpm; adding the ammonia water and the sodium hydroxide solution into a reaction kettle to adjust the base solution, so that the ammonia concentration in the reaction kettle is adjusted to 11g/L, the pH value is adjusted to 10.5, nitrogen is introduced into the reaction kettle, the flow rate of the nitrogen is 50L/h, and the oxygen content in the reaction kettle is 2.5 volume percent;
(3) Adding the mixed salt solution, the sodium hydroxide aqueous solution and the ammonia water into a reaction kettle through a metering pump, wherein the flow rate of the mixed salt solution is set to 240mL/h, the flow rates of the sodium hydroxide solution and the ammonia water are automatically adjusted according to the pH value and the ammonia concentration, performing coprecipitation reaction, testing the granularity of the slurry by a laser granularity meter every 2h in the reaction process, and keeping the pH value in the reaction kettle within a range of 10.5+/-0.1 by adjusting the pH value in the reaction kettle;
(4) To be of particle size D 50 Stopping feeding liquid after reaching 8 μm, alternately washing the obtained coprecipitation reaction product with 75 ℃ 0.2mol/L sodium hydroxide solution and water, and drying at 120 ℃ for 3 hours to obtain the catalyst with the general formula of Ni 0.95 Mn 0.5 (OH) 2 Precursor S4 of (2);
wherein the precursor S4 is a secondary particle composed of primary particles, the primary particles are in an elongated wedge-shaped structure, and the secondary particles have a spherical structure; wherein the precursor S4 has a characteristic double peak of a 001 crystal face in a range of 18.7+/-1 DEG in 2 theta;
(5) The precursor S4, a lithium source (lithium hydroxide) and an M source (TiO) were mixed in an oxygen-containing atmosphere (oxygen content: 95 vol.%) 2 ) Mixing, heating to 800 ℃ at 3 ℃/min, sintering for 12 hours, and cooling to room temperature to obtain the compound of the general formula Li 1.02 Ni 0.945 Mn 0.05 Ti 0.005 O 2 Positive electrode material P4 of (a);
wherein, the dosage ratio of the lithium source satisfies: [ n (Li) ]/[ n (Ni) +n (Mn) +n (M) ]=1.02. The amount of M source is as follows: [ n (M) ]/[ n (Ni) +n (Mn) +n (M) ]=0.005.
Example 5
(1) By metal elementsPlain meter, niSO 4 ·6H 2 O、MnSO 4 ·H 2 O、TiOSO 4 Dissolving the mixture in water according to the mol ratio of 90:9.5:0.5 to prepare 1.7mol/L mixed salt solution; preparing 8mol/L sodium hydroxide solution as a precipitator, and preparing 5mol/L ammonia water as a complexing agent;
(2) Adding deionized water into a 5L reaction kettle, wherein the deionized water is not passed through an upper stirring paddle, controlling the temperature of the reaction kettle at 75 ℃, and setting the stirring rotating speed at 700rpm; adding the ammonia water and the sodium hydroxide solution into a reaction kettle to adjust the base solution, so that the ammonia concentration in the reaction kettle is adjusted to 5g/L, the pH value is adjusted to 10.8, nitrogen is introduced into the reaction kettle, the flow rate of the nitrogen is 50L/h, and the oxygen content in the reaction kettle is 2.5 volume percent;
(3) Adding the mixed salt solution, the sodium hydroxide aqueous solution and the ammonia water into a reaction kettle through a metering pump, wherein the flow rate of the mixed salt solution is set to 240mL/h, the flow rates of the sodium hydroxide solution and the ammonia water are automatically adjusted according to the pH value and the ammonia concentration, performing coprecipitation reaction, testing the granularity of the slurry by a laser granularity meter every 2h in the reaction process, and keeping the pH value in the reaction kettle within a range of 10.8+/-0.1 by adjusting the pH value in the reaction kettle;
(4) To be of particle size D 50 Stopping feeding liquid after reaching 10 μm, alternately washing the obtained coprecipitation reaction product with 75 ℃ 0.2mol/L sodium hydroxide solution and water, and drying at 120 ℃ for 3 hours to obtain Ni with the general formula 0.9 Mn 0.095 Ti 0.005 (OH) 2 Precursor S5 of (2);
wherein the precursor S5 is a secondary particle composed of primary particles, the primary particles are in an elongated wedge-shaped structure, and the secondary particles have a spherical structure; wherein the precursor S5 has a characteristic double peak of a 001 crystal face in a range of 18.7+/-1 DEG in 2 theta;
(5) Mixing the precursor S5 and lithium source (lithium hydroxide) in oxygen-containing atmosphere (oxygen content of 95 vol%) and heating to 800 deg.C at 3deg.C/min for sintering for 12 hr, cooling to room temperature to obtain the product with general formula of Li 1.02 Ni 0.9 Mn 0.095 Ti 0.005 O 2 Positive electrode material P5 of (a);
wherein, the dosage ratio of the lithium source satisfies: [ n (Li) ]/[ n (Ni) +n (Mn) +n (M) ]=1.02.
Example 6
The procedure of example 1 was followed, except,
in the step (1), an M source is added, and NiSO is calculated according to metal elements 4 ·6H 2 O、MnSO 4 ·H 2 O、TiOSO 4 The molar ratio of (2) is replaced by 94.5:5:0.5, the pH value is controlled within the range of 11+/-0.1, and the rest conditions are the same, so that the precursor S6 and the positive electrode material P6 are obtained.
Example 7
The procedure of example 1 was followed, except,
in the step (1), an M source is added, and NiSO is calculated according to metal elements 4 ·6H 2 O、MnSO 4 ·H 2 O、Y 2 O 3 The molar ratio of (2) is replaced by 94.5:5:0.5, the pH value is controlled within the range of 11+/-0.1, and the rest conditions are the same, so that the precursor S7 and the positive electrode material P7 are obtained.
Comparative example 1
The procedure of example 1 was followed, except,
in the step (2), the flow rate of nitrogen is regulated to be 100L/h, so that the oxygen content in the reaction kettle is 0.5 volume percent, the pH is controlled within the range of 11.6+/-0.1, and the rest conditions are the same, thus obtaining the catalyst with the general formula of Ni 0.95 Mn 0.5 (OH) 2 Precursor DS1 of (C) and general formula Li 1.02 Ni 0.945 Mn 0.05 Ti 0.005 O 2 Positive electrode material DP1 of (a).
As shown in fig. 7, the SEM image of the precursor DS1 is that, as shown in fig. 7, the precursor DS1 is a secondary particle composed of primary particles, the primary particles are in an elongated wedge-shaped structure, and the secondary particles have a spherical structure;
as shown in fig. 8, the XRD pattern of the precursor DS1 shows that the diffraction peak of the precursor DS1 at the 001 crystal plane is a single peak as shown in fig. 8.
Comparative example 2
The procedure of example 1 was followed, except,
in the step (2), compressed air is introduced, the oxygen content in the reaction kettle is controlled to be 16 volume percent, and other conditions are the sameIn the same way, ni is obtained 0.95 Mn 0.5 (OH) 2 Precursor DS2 of (C) and formula Li 1.02 Ni 0.945 Mn 0.05 Ti 0.005 O 2 Is a positive electrode material DP2 of the battery.
Comparative example 3
The procedure of example 1 was followed, except,
in step (5), the M source species is replaced with CoSO 4 The remaining conditions were the same, to obtain a positive electrode material DS3.
TABLE 1
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Note that: 1-liquid feed flow rate of mixed salt solution, mL/h.
Table 1, below
TABLE 2
Note that: * -2θ has a characteristic bimodal of 001 crystal planes in the range of 19±1.5°.
Continuous table 2
Continuous table 2
Note that: 2-K 90 ＝(D 90 -D 10 )/D 50 ，D 90 、D 10 And D 50 The particle sizes of the precursor in the particle size distribution are respectively 90%, 10% and 50%, and the unit is mu m.
Continuous table 2
As can be seen from the data of tables 1 to 2, examples 1 to 7, compared with comparative examples 1 to 3, produced precursors S1 to S7 each having XRD diffraction 001 double peaks and satisfying 1.5.ltoreq.I by controlling the oxygen content in the reaction system to 0.5 to 10% by volume and the pH to 10 to 11.3 (101) /I (001) And the crystallinity of the precursor is improved by less than or equal to 3, so that the crystallinity of the precursor is improved, and the positive electrode material prepared by sintering the precursor has higher tap density on the premise of meeting the structural stability.
Meanwhile, the precursor prepared in examples 1 to 7 further defines the characteristic double peaks of the 001 crystal plane to include a single peak A and a single peak B, and defines half-peak width, peak intensity and peak area parameters of the single peak A and the single peak B, so that the precursor has the characteristics of larger BET and tap density and narrow particle size distribution.
Test case
The positive electrode materials prepared in examples and comparative examples were subjected to electrochemical performance test.
Assembling a battery: and respectively weighing the positive electrode material, the conductive carbon black and polyvinylidene fluoride (PVDF) according to the mass ratio of 95:2.5:2.5, mixing, adding NMP, stirring to form uniform slurry, coating the uniform slurry on aluminum foil, strickling, rolling to be flat after drying treatment, stamping into a positive electrode plate with the diameter of 12mm and the thickness of 120 mu m at the pressure of 100MPa, and then placing in a vacuum oven for drying at 120 ℃ for 12 hours to obtain the positive electrode plate.
The button cell assembly process is carried out in an Ar gas protected glove box, wherein the water content and the oxygen content are both less than 5ppm; the positive electrode uses the pole piece obtained in the above way, and the negative electrode uses a Li metal piece with the diameter of 17mm and the thickness of 1 mm; the separator was a polyethylene porous film having a thickness of 25. Mu.m, the electrolyte was an equal amount of a mixture of Ethylene Carbonate (EC) and ethylene carbonate (DEC) in which LiPF6 was dissolved at 1mol/L, and the battery case was a button-type battery case having a model number of 2025. After assembly, an unactivated cell was obtained.
The performance of the assembled lithium ion battery was tested, and the test results are shown in table 3, respectively. The charging capacity of the lithium ion battery is measured according to a method that the button battery which is placed for 2 hours after the assembly is taken out, the button battery is charged to the cut-off voltage of 4.3V by cross current at the room temperature by 0.1C (1 C=200 mA/g), and then the button battery is charged for 30 minutes at constant voltage;
The discharge capacity was measured by discharging the charged button cell at room temperature to 3.0V at a constant current of 0.1C;
the first time efficiency was measured by dividing the above-mentioned 0.1C discharge capacity by the 0.1C charge capacity;
the multiplying power performance of 1C/0.1C is measured according to the method that the button cell after completing 0.1C charging and discharging is subjected to constant current charging and discharging by 0.2C, 0.33C, 0.5C and 1C in sequence at room temperature, the voltage window is 4.3-3.0V, and the 1C discharge capacity is divided by 0.1C discharge capacity;
the 80-week cycle retention rate was measured by taking the button cell having completed 0.1C charge and discharge once, cycling at room temperature for 80 weeks with a 1C constant current charge and discharge, and voltage window of 4.3-3.0V, and dividing the 80 th week discharge capacity by the 1 st week discharge capacity.
TABLE 3 Table 3
As can be seen from the data in table 3, the lithium ion batteries assembled from the positive electrode materials prepared in examples 1 to 7 have higher capacity performance, rate performance and cycle performance than those of comparative examples 1 to 3.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.

Claims (16)

1. A nickel-manganese binary precursor is characterized in that the precursor has a composition shown in a formula I, ni x Mn y M z (OH) 2 (I) X is more than or equal to 0.8 and less than 1, y is more than or equal to 0 and less than or equal to 0.2, z is more than or equal to 0 and less than or equal to 0.1, x+y+z=1, and M is selected from at least one non-Co element;
in powder X-ray diffraction measurement of the precursor by adopting CuK alpha rays, 2 theta has a characteristic double peak of a 001 crystal face within a range of 19+/-1.5 degrees.
2. The precursor of claim 1, wherein in formula I0.85 +.x +. 0.99,0.01 +.y +. 0.15,0.001 +.z +.0.1 and x+y+z = 1, m is selected from at least one element of La, cr, mo, ca, fe, hf, ti, zn, Y, zr, si, W, nb, sm, V, mg, B, Y and Al;
and/or, in the formula I, x is more than or equal to 0.9 and less than or equal to 0.98,0.02, y is more than or equal to 0.1,0.001 and less than or equal to z is more than or equal to 0.01, and x+y+z=1, wherein M is at least one element selected from La, cr, mo, hf, ti, zn, Y, zr, W, nb, V, mg, B, Y and Al.
3. The precursor according to claim 1 or 2, wherein the peak intensity ratio of the characteristic peak of 101 crystal plane to the characteristic peak of 001 crystal plane in powder X-ray diffraction measurement of the precursor using cuka radiation satisfies: i (101) /I (001) The characteristic peak 2 theta of the 101 crystal face is more than or equal to 1.5 and is within the range of (37-41);
preferably, the following are satisfied: i is less than or equal to 1.5 (101) /I (001) ≤3。
4. A precursor according to any one of claims 1-3, wherein the 001 plane is characterized by a bimodal shapePeak intensity I of (2) (101) 300-4000, full width at half maximum FWHM (101) Is (0.5-2) °;
and/or, the peak intensity I of the characteristic double peaks of the 001 crystal face (101) 500-3000, full width at half maximum FWHM (101) Is (0.6-1.8) °.
5. The precursor of any one of claims 1-4, wherein the characteristic doublet of the 001 crystal plane comprises a single peak a and a single peak B, and the single peak a is located to the left of the single peak B;
preferably, the peak intensities of the single peak a and single peak B satisfy: 500 is less than or equal to I (A) ≤2000，600≤I (B) ≤2000，0.35≤I (A)/ I (B) ≤2.4；
Preferably, the half-widths of the single peak a and the single peak B satisfy: FWHM of 0.4 DEG or less (A) ≤0.7°，0.4°≤FWHM (B) ≤0.6°，0.7≤FWHM (A) /FWHM (B) ≤1.5；
Preferably, the peak areas of the single peak a and the single peak B satisfy: 10000 is less than or equal to A (A) ≤70000，10000≤A (B) ≤75000，0.6≤A (A) /A (B) ≤2.2。
6. The precursor according to any one of claims 1-5, wherein the precursor is a secondary particle consisting of primary particles, the primary particles having a wedge-shaped structure;
and/or, the precursor has a spherical structure;
and/or the BET of the precursor is 3-25m 2 Preferably 5-20m 2 /g; tap density is more than or equal to 1g/cm 3 Preferably 1.3-2.5g/cm 3 ；
And/or the particle size distribution K of the precursor 90 The method meets the following conditions: k is more than or equal to 0.4 90 Not more than 0.8, wherein K 90 ＝(D 90 -D 10 )/D 50 ，D 90 、D 10 And D 50 The particle sizes of the precursor in the particle size distribution are respectively 90%, 10% and 50%, and the units are mu m;
and/or D of the precursor 50 Is 6-20 μm, preferably 8-14 μm.
7. The preparation method of the nickel-manganese binary precursor is characterized by comprising the following steps of: mixing the mixed salt solution, the complexing agent and the precipitator, performing coprecipitation reaction, regulating the oxygen content in the reaction system to be 0.5-10% by volume and the pH value to be 10-11.3, and sequentially washing and drying the obtained coprecipitation reaction product to obtain a precursor;
wherein the mixed salt solution is selected from an aqueous solution containing a nickel salt, a manganese salt, and optionally an M source, wherein M is selected from at least one non-Co element.
8. The production method according to claim 7, wherein the oxygen content in the reaction system is regulated to 0.5 to 8% by volume;
and/or, when the complexing agent is selected from the group consisting of ammonium ion-containing compounds, regulating the ammonia concentration in the reaction system to be 1-12g/L, preferably 3-8g/L;
and/or, the conditions of the coprecipitation reaction include: the temperature is 50-80 ℃, and the pH value is 10-11.3, preferably 10.3-11.1; the rotating speed is 250-750rpm;
and/or, the nickel salt, manganese salt and M source satisfy n (Ni) n (Mn) n (M), n (Ni) is more than or equal to 0.8 and less than or equal to 1, n (Mn) is more than or equal to 0 and less than or equal to 0.2, n (M) is more than or equal to 0 and less than or equal to 0.1; further preferably, 0.85.ltoreq.n (Ni). Ltoreq. 0.99,0.01.ltoreq.n (Mn). Ltoreq. 0.15,0.001.ltoreq.n (M). Ltoreq.0.1; more preferably, 0.9.ltoreq.n (Ni). Ltoreq. 0.98,0.02.ltoreq.n (Mn). Ltoreq. 0.1,0.001.ltoreq.n (M). Ltoreq.0.01;
And/or, M in the M source is at least one element selected from La, cr, mo, ca, fe, hf, ti, zn, Y, zr, si, W, nb, sm, V, mg, B, Y and Al, preferably at least one element selected from La, cr, mo, hf, ti, zn, Y, zr, W, nb, V, mg, B, Y and Al;
and/or the liquid inlet flow rate of the mixed metal salt is 50-300mL/min, preferably 150-250mL/min;
and/or, the washing process comprises: alternatively performing alkali washing and water washing on the coprecipitation reaction product;
and/or, the drying conditions include: the temperature is 80-150 ℃ and the time is 2-6h.
9. Use of the precursor according to any one of claims 1-6, or the precursor prepared by the preparation method according to claim 7 or 8, in a positive electrode material.
10. A positive electrode material, characterized in that the positive electrode material is produced from the precursor according to any one of claims 1 to 6, or the precursor produced by the production method according to claim 7 or 8, by sintering.
11. The positive electrode material of claim 10, wherein the positive electrode material is made by a method comprising: mixing the precursor, a lithium source and an M source and performing sintering in an oxygen-containing atmosphere when the precursor does not contain a doping element M to obtain the positive electrode material; or alternatively, the process may be performed,
When the precursor contains doping element M, mixing the precursor with a lithium source and sintering to obtain the anode material;
wherein M in the M source is selected from at least one non-Co element.
12. The positive electrode material according to claim 11, wherein the lithium source is used in an amount ratio satisfying 0.9.ltoreq.n (Li) ]/[ n (Ni) +n (Mn) +n (M) ].ltoreq.1.2;
preferably satisfies 1.ltoreq.n (Li) ]/[ n (Ni) +n (Mn) +n (M) ]. Ltoreq.1.1;
more preferably, 1.01.ltoreq.n (Li) ]/[ n (Ni) +n (Mn) +n (M) ].ltoreq.1.06;
and/or, the amount of the M source satisfies: 0.ltoreq.n (M) ]/[ n (Ni) +n (Mn) +n (M) ]. Ltoreq.0.1, more preferably: 0.001.ltoreq.n (M) ]/[ n (Ni) +n (Mn) +n (M) ].ltoreq.0.1, more preferably: less than or equal to [ n (M) ]/[ n (Ni) +n (Mn) +n (M) ] less than or equal to 0.001;
and/or at least one element selected from Al, fe, mg, B, ca, sr, ba, zr, ti, ce, Y, W, la, nb, ta, zn, co and Mo, preferably at least one element selected from La, cr, mo, hf, ti, zn, Y, zr, W, nb, V, mg, B, Y and Al, in the M source.
13. The cathode material of claim 11 or 12, wherein the oxygen content in the oxygen-containing atmosphere is equal to or greater than 80 volume%, preferably equal to or greater than 95 volume%;
and/or, the sintering conditions include: the temperature is 600-900 ℃, preferably 700-800 ℃; the time is 0.1-20h, preferably 0.1-15h; the heating rate is 1-20deg.C/min, preferably 1-5deg.C/min.
14. The positive electrode material according to any one of claims 10 to 13, wherein the positive electrode material has a composition represented by formula II, li 1+a Ni α Mn β M γ O 2 (II)；
Wherein, -0.1 is more than or equal to a and less than or equal to 0.2,0.8 is more than or equal to alpha and less than 1,0 is more than or equal to beta and less than or equal to 0.2,0 is more than or equal to gamma and less than or equal to 0.1, and alpha+beta+gamma=1; m is selected from at least one non-Co element;
preferably, in the formula II, a is more than or equal to 0 and less than or equal to 0.1,0.85, alpha is more than or equal to 0.99,0.01, beta is more than or equal to 0.15,0.001, gamma is more than or equal to 0.1, and α+β+γ=1; m is at least one element selected from La, cr, mo, ca, fe, hf, ti, zn, Y, zr, si, W, nb, sm, V, mg, B, Y and Al;
further preferably, in the formula II, a is more than or equal to 0.01 and less than or equal to 0.06,0.9, alpha is more than or equal to 0.98,0.02, beta is more than or equal to 0.1,0.001, gamma is more than or equal to 0.01, and alpha+beta+gamma=1; m is at least one element selected from La, cr, mo, hf, ti, zn, Y, zr, W, nb, V, mg, B, Y and Al.
15. The positive electrode material according to any one of claims 10 to 14, wherein the tap density of the positive electrode material is not less than 2.5g/cm 3 Preferably 2.5-3g/cm 3 ；
And/or the positive electrode material has a layered structure.
16. A lithium ion battery, characterized in that it contains the positive electrode material according to any one of claims 10 to 15.
CN202310802539.8A 2023-06-30 2023-06-30 Nickel-manganese binary precursor, preparation method and application thereof, positive electrode material and lithium ion battery Pending CN116675264A (en)

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