CN115566162B - Lithium-containing oxide positive electrode material precursor, lithium-containing oxide positive electrode material, preparation method and application of lithium-containing oxide positive electrode material precursor, positive electrode plate and application of positive electrode plate - Google Patents

Lithium-containing oxide positive electrode material precursor, lithium-containing oxide positive electrode material, preparation method and application of lithium-containing oxide positive electrode material precursor, positive electrode plate and application of positive electrode plate

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CN115566162B
CN115566162B CN202211166346.XA CN202211166346A CN115566162B CN 115566162 B CN115566162 B CN 115566162B CN 202211166346 A CN202211166346 A CN 202211166346A CN 115566162 B CN115566162 B CN 115566162B
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lithium
electrode material
containing oxide
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CN115566162A (en
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王俊
刘亚飞
陈彦彬
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Beijing Easpring Material Technology Co Ltd
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    • 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
    • C—CHEMISTRY; METALLURGY
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    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/40—Complex oxides containing nickel and at least one other metal element
    • C01G53/42—Complex oxides containing nickel and at least one other metal element containing alkali metals, e.g. LiNiO2
    • C01G53/44—Complex oxides containing nickel and at least one other metal element containing alkali metals, e.g. LiNiO2 containing manganese
    • C01G53/50—Complex oxides containing nickel and at least one other metal element containing alkali metals, e.g. LiNiO2 containing manganese of the type (MnO2)n-, e.g. Li(NixMn1-x)O2 or 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
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    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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    • 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
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    • 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
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    • C01P2006/40—Electric properties
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    • Y02E60/10—Energy storage using batteries

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Abstract

本发明涉及锂离子电池技术领域，公开了一种含锂氧化物正极材料前驱体和含锂氧化物正极材料及其制备方法与应用、正极片及其应用。所述正极材料的抗压指数Δλ(P100)满足：Δλ(P100)≥60％+(y/x)×5％；其中，y/x为正极材料中Mn/Ni的摩尔比。该含锂氧化物正极材料具有较高的抗压强度和稳定性，在电极片制作过程中能够在承受较高压力下仅发生较小程度的破碎，且能够持续进行锂离子脱出/嵌入反应而不发生严重的破裂。

The present invention relates to the field of lithium-ion battery technology, and discloses a lithium oxide-containing positive electrode material precursor and a lithium oxide-containing positive electrode material, as well as preparation methods and applications thereof, a positive electrode sheet, and applications thereof. The positive electrode material has a compressive index Δλ(P 100 ) that satisfies the following: Δλ(P 100 ) ≥ 60% + (y/x) × 5%, where y/x is the molar ratio of Mn/Ni in the positive electrode material. The lithium oxide-containing positive electrode material exhibits high compressive strength and stability, can withstand high pressures with minimal breakage during electrode sheet fabrication, and can sustain lithium ion extraction and insertion reactions without severe rupture.

Description

Lithium-containing oxide positive electrode material precursor, lithium-containing oxide positive electrode material, preparation method and application of lithium-containing oxide positive electrode material precursor, positive electrode plate and application of positive electrode plate
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a lithium-containing oxide positive electrode material precursor, a lithium-containing oxide positive electrode material, a preparation method and application of the lithium-containing oxide positive electrode material precursor, a positive electrode sheet and application of the positive electrode sheet.
Background
In recent years, new energy automobiles are emerging as national strategy industry for coping with environmental pollution and energy crisis, and a good situation of vigorous development is presented, and lithium ion batteries are widely applied to markets of electric automobiles, energy storage power stations, communication, digital electronic products and the like as new energy carriers with excellent comprehensive performance.
In lithium ion batteries, the positive electrode is used as a core key material of the lithium ion battery, and directly determines the technical performance level of the battery. Among commonly used lithium ion battery cathode materials, liNi 1-x-yCoxMnyO2 (NCM) and LiNi 1-x-yCoxAlyO2 (NCA) having a layered structure and lithium-rich manganese-based materials (LMR) are receiving attention and study due to high specific capacity and energy density. However, in order to obtain higher volumetric energy density and comprehensive electrochemical performance, the positive electrode material is rolled with higher strength in the process of manufacturing the battery pole piece so as to obtain high electrode density. The low-strength cathode material is crushed or broken in the process, the contact area with the electrolyte is increased, and side reactions are caused, so that the cycle performance and the rate performance are deteriorated. In addition, repeated deintercalation of Li + during battery use can expand and contract the volume of the layered structure, so that the low-strength cathode material is pulverized, insufficient inter-particle contact is caused, a new electrolyte layer is continuously formed, side reactions are increased, and battery performance is deteriorated and fails.
Therefore, the development of a novel preparation method and the regulation of the microstructure of the layered positive electrode material enhance the compressive strength or the particle strength of the positive electrode material, and have very important significance for realizing long cycle life, high specific capacity, high rate performance and the like of the battery.
Disclosure of Invention
The invention aims to overcome the defects that in the prior art, lithium-containing metal oxide materials are broken in the process of manufacturing electrode plates or secondary particles are broken in the process of charge-discharge circulation to cause poor multiplying power performance, poor circulation performance and low safety performance, and provides a lithium-containing oxide positive electrode material precursor, a lithium-containing oxide positive electrode material, a preparation method and application thereof, a positive electrode plate and application thereof.
In order to achieve the above object, a first aspect of the present invention provides a lithium-containing oxide positive electrode material, wherein a compressive index Δλ (P 100) of the positive electrode material satisfies Δλ (P 100) > 60++ (y/x) ×5%;
Wherein y/x is the molar ratio of Mn/Ni in the positive electrode material.
The second aspect of the invention provides a lithium-containing oxide positive electrode material precursor, wherein the compressive index delta lambda '(P 50) of the precursor meets the conditions that delta lambda' (P 50) is more than or equal to 35% + (v/u) multiplied by 8%;
Wherein v/u is the molar ratio of Mn/Ni in the precursor.
The third aspect of the invention provides a preparation method of a lithium-containing oxide cathode material, wherein the preparation method comprises the following steps:
s1, uniformly mixing a precursor with a chemical formula shown in a formula (1), a lithium source and an optional additive containing an element M 2, and performing primary sintering in an atmosphere furnace to obtain a primary sintering material with a chemical formula shown in a formula (2);
s2, uniformly mixing the primary sintering material with an additive containing an element M', and performing secondary sintering on the mixed material in an atmosphere furnace to obtain a lithium-containing metal oxide with a chemical formula shown in a formula (3);
Ni uMnvM1γ(OH)2, formula (1);
Wherein u+v+γ=1, 0.2< u <1,0< v≤ 0.75,0≤γ≤0.35, m 1 is at least one element selected from Al, zr, nb, ti, Y, sc, cr, co, W, mg, na, la, os, pr, re, ru, sr, sm, ta and B;
Li [ Li aNixMnyMj]O2, formula (2);
Li [ Li aNixMnyMj]O2 @ M', formula (3);
wherein, in the formula (2) and the formula (3):
a+x+y+j=1,0≤a≤0.3,0.2<x<1,0<y≤0.75,0<j≤0.35;
M comprises M 1 element in the precursor, and M 2 element is introduced in the first sintering process;
m 1、M2, which are the same or different, are each at least one element selected from Al, zr, nb, ti, Y, sc, cr, co, W, mg, la, os, pr, re, ru, sr, sm, ta and B;
In formula (3):
M 'is oxide, phosphide, sulfide, fluoride or chloride containing at least one element of Al, zr, nb, ti, Y, sc, cr, co, W, mg, la, os, pr, re, ru, sr, sm, ta and B, and the molar content of cations in M' is w, 0<w/(a+x+y+j) is less than or equal to 0.1.
The fourth aspect of the present invention provides a lithium-containing oxide cathode material prepared by the aforementioned method for preparing a lithium-containing oxide cathode material.
The fifth aspect of the present invention provides a positive electrode sheet, wherein the positive electrode sheet comprises at least 90wt% of a lithium-containing oxide positive electrode material, based on the total weight of the positive electrode sheet;
The lithium-containing oxide positive electrode material is the lithium-containing oxide positive electrode material.
The sixth aspect of the invention provides an application of the lithium-containing oxide positive electrode material, the lithium-containing oxide positive electrode material precursor or the positive electrode sheet in a lithium ion battery.
Through the technical scheme, the invention has the following advantages:
(1) The lithium-containing oxide positive electrode material and the precursor provided by the invention realize high crystallinity and densification of the precursor through the control of a specific microstructure, so that the compressive index of the positive electrode material is improved;
(2) According to the invention, through proper modifier and doping element, the compression resistance index, the cycle life and the safety performance of the material can be improved;
(3) The sintering system in the preparation process of the lithium-containing metal oxide influences the compression resistance index of the material, so that the cost, the compression resistance index of the material, the physical index of the material, the electrochemical performance and the like are considered when the sintering system is selected.
Drawings
FIG. 1 is a comparative schematic diagram of charge-discharge curves of example 5 and comparative example 1;
FIG. 2 is a comparative schematic diagram of the cycle performance of example 5 and comparative example 1;
FIG. 3 is a comparative schematic diagram of charge-discharge curves of example 5 and comparative example 2;
FIG. 4 is a comparative schematic diagram of the cycle performance of example 5 and comparative example 2;
FIG. 5 is a comparative schematic diagram of charge-discharge curves of example 5 and comparative example 3;
FIG. 6 is a comparative schematic diagram of the cycle performance of example 5 and comparative example 3;
FIG. 7 is a comparative schematic diagram of charge-discharge curves of example 5 and comparative example 4;
FIG. 8 is a comparative schematic diagram of the cycle performance of example 5 and comparative example 4;
FIG. 9 is a comparative schematic diagram of charge-discharge curves of example 9 and comparative example 5;
FIG. 10 is a comparative schematic of the cycle performance of example 9 and comparative example 5;
FIG. 11 is a comparative schematic diagram of charge-discharge curves of example 9 and comparative example 6;
FIG. 12 is a comparative schematic of the cycle performance of example 9 and comparative example 6;
FIG. 13 is a comparative schematic diagram of charge-discharge curves of example 9 and comparative example 7;
FIG. 14 is a comparative schematic diagram of the cycle performance of example 9 and comparative example 7.
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.
For the conventional lithium-containing metal oxide material for the lithium ion battery, the electrode plate is subjected to higher pressure in the preparation process and is broken due to insufficient compressive strength or unstable structure in the continuous charge-discharge cycle process, so that side reaction with electrolyte is increased, consumption of the electrolyte and dissolution of transition metal cations in the positive electrode material are accelerated, and the cycle performance, safety performance and capacity are reduced, and even the battery is disabled.
As previously described, the first aspect of the present invention provides a lithium-containing oxide positive electrode material, wherein the positive electrode material has a compressive index Δλ (P 100) satisfying Δλ (P 100) > 60++ (y/x) ×5%;
Wherein y/x is the molar ratio of Mn/Ni in the positive electrode material.
In addition, in the present invention:
Wherein the method comprises the steps of Refers to the value of the particle accumulation distribution D 5 of the material in a natural state without external mechanical pressure (i.e. p=0 Mpa),Refers to the value of the particle cumulative distribution D 5 of the material at p=n Mpa, and D 5 refers to the particle size value at which the particle cumulative volume distribution is 5%.
For example, the compressive index Δλ (P 100) is calculated by:
According to the present invention, the positive electrode material preferably has a compressive index Δλ (P 200) satisfying Δλ (P 200) > 45++ (y/x) ×5%.
According to the present invention, more preferably, the cathode material has a compressive index Δλ (P 300) satisfying Δλ (P 300) > 35++ (y/x) ×5%.
According to the invention, Δλ (P 100) represents the compression resistance index of the material at a pressure p=100 Mpa, Δλ (P 200) represents the compression resistance index of the material at a pressure p=200 Mpa, and so on.
The positive electrode material provided by the invention has the advantages of excellent compressive strength, difficult cracking, stable structure, less side reaction, excellent safety performance and excellent capacity retention rate in the application process of being used as a positive electrode.
According to the present invention, the lithium-containing oxide positive electrode material has a chemical formula represented by formula (3):
Li [ Li aNixMnyMj]O2 @ M', formula (3);
wherein a+x+y+j=1, 0.2< x <1,0< y < 0.75,0< j < 0.35, M is at least one element selected from Al, zr, nb, ti, Y, sc, cr, co, W, mg, la, os, pr, re, ru, sr, sm, ta and B, M 'is an oxide, phosphide, sulfide, fluoride or chloride containing at least one element of Al, zr, nb, ti, Y, sc, cr, co, W, mg, la, os, pr, re, ru, sr, sm, ta and B, and the molar content of cations in M' is w, 0<w/(a+x+y+j) is less than or equal to 0.1.
According to the present invention, preferably 0.02≤a≤0.3, 0.3< x <0.9,0.05< y≤0.68, 0< j≤0.3, 0.001< w/(a+x+y+j). Ltoreq.0.02.
According to the invention, M is at least one element selected from Zr, nb, ti, Y, sc, cr, co, W, mg, la, ta and B, M' is an oxide, phosphide, sulfide or fluoride containing at least one element from Zr, nb, ti, Y, sc, cr, co, W, mg, la, ta and B.
In the present invention, the inventors of the present invention found that:
By adopting a proper modifier, the compressive strength and stability of the material particles can be enhanced, the direct current internal resistance value and gas production amount of the material in the circulation process are reduced, and the circulation life of the material is prolonged.
Doping Ti, sc, zr, W, mg, Y, co, cr, ta and other elements can stabilize the crystal structure of the material, improve the micro-area structure of the material, improve the compression resistance index, the cycle life and the safety performance of the material, doping Ti, zr, nb, la, W, co, B and other elements can form lithium-containing compounds (such as LiNbO 3, li 2ZrO3, li 4Ti5O12, li 3BO3, laNiO 3 and the like) on the surfaces of the material particles or at interfaces among the particles, stabilize the surface structure of the particles or the interface strength among the particles or the grain boundary structure among primary grains, improve the compression resistance index and the cycle life of the material, accelerate the transmission of lithium ions among the particles and among the interfaces, and improve the rate capability of the material. The positive electrode material provided by the invention is further characterized in that:
According to the invention, the tap density of the positive electrode material is not less than 1.7g/cm 3, preferably not less than 2g/cm 3, more preferably not less than 2.4g/cm 3.
According to the invention, the positive electrode material has a compacted density of not less than 2.8g/cm 3, preferably not less than 3g/cm 3, more preferably not less than 3.2g/cm 3.
According to the invention, the surface-soluble alkali content of the positive electrode material satisfies the following conditions:
Li2CO3≤1wt%,LiOH≤0.5wt%;
preferably Li 2CO3 -0.5 wt% and LiOH 0.4wt%;
more preferably, li 2CO3 is less than or equal to 0.3wt percent, and LiOH is less than or equal to 0.3wt percent;
more preferably, li 2CO3 is not more than 0.2% by weight and LiOH is not more than 0.2% by weight.
According to the present invention, the positive electrode material satisfies the following conditions in terms of the full width at half maximum FWHM (003) of the (003) plane and the full width at half maximum FWHM (104) of the (104) plane obtained by XRD:
FWHM (003) less than or equal to 0.10 less than or equal to 0.25, preferably 0.13 less than or equal to FWHM (003) less than or equal to 0.22;
FWHM (104)≤0.20≤0.50, preferably, FWHM (104) is less than or equal to 0.22 and less than or equal to 0.42.
According to the present invention, the peak areas S (003) and S (104) of the (003) and (104) crystal planes obtained by XRD of the positive electrode material satisfy the following conditions:
S (003)/S(104) is 1.1≤1.8, preferably S (003)/S(104) is 1.2≤1.6.
Besides adopting proper additives, the invention realizes high crystallinity and densification of the precursor through the control of the morphology and microstructure of the precursor, thereby improving the compressive index of the positive electrode material.
The second aspect of the invention provides a lithium-containing oxide positive electrode material precursor, wherein the compressive index delta lambda '(P 50) of the precursor meets the conditions that delta lambda' (P 50) is more than or equal to 35% + (v/u) multiplied by 8%;
Wherein v/u is the molar ratio of Mn/Ni in the precursor.
According to the invention, the precursor preferably has a compression resistance index Δλ '(P 100) satisfying Δλ' (P 100). Gtoreq.25++ (v/u). Times.8%.
According to the invention, Δλ '(P 50) represents the compressive index of the precursor material at a pressure p=50 MPa, Δλ' (P 100) represents the compressive index of the precursor material at a pressure p=100 MPa, and so on.
In the present invention,
Wherein the method comprises the steps ofRefers to the value of the particle cumulative distribution D 5 of the precursor material in the natural state without external mechanical pressure (i.e. p=0 MPa),Refers to the particle cumulative distribution D 5 value of the precursor material at p= nMPa.
For example, the compressive index Δλ' (P 50) of the precursor is calculated as follows:
according to the present invention, the precursor has a chemical formula represented by formula (1):
Ni uMnvMγ(OH)2, formula (1);
Wherein u+v+γ=1, 0.2< u <1,0< v≤ 0.75,0≤γ≤0.35, m being at least one element selected from Al, zr, nb, ti, Y, sc, cr, co, W, mg, na, la, os, pr, re, ru, sr, sm, ta and B;
Preferably, the method comprises the steps of, u is more than or equal to 0.3 and less than or equal to 0.9,0.05 and less than or equal to 0.68,0, gamma is more than or equal to 0.3, and M is at least one element selected from Ti, al, zr, W, co, nb, la, na and Mg. In the invention, doping Ti, al, zr, W, co, nb, la, na, mg and other elements can stabilize the internal or surface structure of the precursor micro-region.
The precursor material provided by the invention is further characterized in that:
according to the invention, the tap density of the precursor is more preferably not less than 1.2g/cm 3, preferably not less than 1.6g/cm 3, and even more preferably not less than 2g/cm 3.
According to the invention, the specific surface area BET value of the precursor is such that BET is 30m 2/g or less, preferably 25m 2/g or less.
According to the invention, the particle size distribution coefficient K 90 of the precursor is 0.5-K 90 -1.6, wherein K 90＝(D90-D10)/D50,D10、D50 and D 90 respectively refer to particle size values when the cumulative volume distribution of the particles is 10%, 50% and 90%.
According to the present invention, the full width at half maximum FWHM (001) of the (001) crystal plane, the full width at half maximum FWHM (100) of the (100) crystal plane, and the full width at half maximum FWHM (101) of the (101) crystal plane obtained by XRD of the precursor satisfy the following conditions:
FWHM (001) and FWHM (001) and FWHM (001) measured by an X-ray diffractometer are not less than 0.3 and not more than 1, preferably not less than 0.5 and not more than 0.8, respectively;
FWHM (100) 0.10-0.5, preferably FWHM (100) 0.25-0.35;
FWHM (101) is 0.30 or less and 1.0 or less, preferably 0.4 or less FWHM (101) is 0.8 or less.
According to the invention, the peak area S (101) of the (001) crystal face and the peak area S (104) of the (101) crystal face obtained by XRD of the precursor meet the following condition that S (001)/S(101) is more than or equal to 2.0.
According to the invention, the integral area S (101) of the (001) crystal face and the integral area S (104) of the (101) crystal face obtained by XRD of the precursor meet the following condition that S (001)/S(101) is more than or equal to 2.0.
The invention also provides a preparation method of the lithium-containing oxide positive electrode material precursor, wherein the preparation method comprises the following steps:
(1) Mixing nickel salt, manganese salt and solution or suspension of the compound containing M in a contact manner to obtain mixed salt solution;
(2) And (3) the mixed salt solution, the precipitator solution and the complexing agent solution flow into a reaction kettle to carry out crystallization reaction, and then the obtained slurry is subjected to solid-liquid separation, washing, heat treatment and screening treatment to obtain the precursor of the lithium-containing oxide anode material.
In the present invention, the inventors found that, for a metal hydroxide precursor, cracking occurs due to insufficient compressive strength of the precursor during the compounding and sintering, resulting in reduced compressive strength, reduced tap density, and reduced electrochemical performance of the prepared cathode material. In the invention, the synthesis of the precursor with high crystallinity and densification can be realized by controlling the synthesis process of the precursor, such as the concentration and the type of a complexing agent, the concentration of a precipitator, the stirring intensity, the reaction temperature, an additive, the solid content, the feeding rate and the like, and the particle size distribution and the specific surface area of the precursor are regulated so as to improve the crystallinity, the tap density and the compression resistance index of the precursor material, and the compression resistance index of the precursor can be improved by adding a proper additive and regulating the microstructure and the morphology of the precursor.
According to the invention, nickel salt, manganese salt or an additive containing M element is dissolved into mixed salt solution with the concentration of 1-3mol/L according to the mol ratio u:v:gamma, a compound containing M is added into water to prepare M solution or suspension with certain concentration, alkali is dissolved into alkali solution with the concentration of 2-10mol/L, and complexing agent is dissolved into complexing agent solution with the concentration of 2-13 mol/L.
According to the invention, the slurry has a solids content of 200-1000g/L, preferably 300-800g/L.
According to the invention, the mixed salt solution of Ni and Mn, alkali liquor, complexing agent solution and M solution are respectively added into a reaction kettle with an overflow pipeline in parallel flow through respective liquid inlet pipelines, the stirring rotation speed is kept constant, and the liquid inlet flow rates of the mixed salt solution, precipitant solution, complexing agent solution and M solution are controlled.
According to the invention, the reaction conditions include a reaction temperature of 40-70 ℃, a reaction pH of 10.6-12.5, and a reaction time of 5-100h.
According to the invention, the nickel salt is one or more of nickel sulfate, nickel chloride, nickel nitrate and nickel acetate.
According to the invention, the manganese salt is one or more of manganese sulfate, manganese chloride, manganese nitrate and manganese acetate.
According to the invention, the compound containing M is one or more of sulfate, chloride, nitrate, acetate, citrate, carbonate, phosphate, oxalate and fluoride containing M element.
According to the invention, the precipitant is alkali substance, and the alkali is one or more of sodium hydroxide, potassium hydroxide and lithium hydroxide.
According to the invention, the complexing agent is one or more of salicylic acid, ammonium sulfate, ammonium chloride, ammonia water, sulfosalicylic acid and ethylenediamine tetraacetic acid.
According to the invention, the sintering schedule (including sintering temperature, heating rate, sintering atmosphere, etc.) in the preparation process of the lithium-containing metal oxide is also very important, and the compressive index of the material is affected.
The third aspect of the invention provides a preparation method of a lithium-containing oxide cathode material, wherein the preparation method comprises the following steps:
S1, uniformly mixing a precursor with a chemical formula shown in a formula (1), a lithium source and an optional additive containing an element M 2, and performing primary sintering on the mixed material in an atmosphere furnace to obtain a primary sintered material with the chemical formula shown in a formula (2);
s2, uniformly mixing the primary sintering material with an additive containing an element M', and performing secondary sintering on the mixed material in an atmosphere furnace to obtain a lithium-containing metal oxide with a chemical formula shown in a formula (3);
Ni uMnvM1γ(OH)2, formula (1);
Wherein u+v+γ=1, 0.2< u <1,0< v≤ 0.75,0≤γ≤0.35, m 1 is at least one element selected from Al, zr, nb, ti, Y, sc, cr, co, W, mg, na, la, os, pr, re, ru, sr, sm, ta and B;
Li [ Li aNixMnyMj]O2 ], formula (2);
Li [ Li aNixMnyMj]O2 @ M', formula (3);
wherein, in the formula (2) and the formula (3):
0≤a≤0.3,0.2<x<1,0<y≤0.75,0<j≤0.35;
M comprises M 1 element in the precursor, and M 2 element is introduced in the first sintering process;
m 1、M2, which are the same or different, are each at least one element selected from Al, zr, nb, ti, Y, sc, cr, co, W, mg, la, os, pr, re, ru, sr, sm, ta and B;
In formula (3):
M 'is oxide, phosphide, sulfide, fluoride or chloride containing at least one element of Al, zr, nb, ti, Y, sc, cr, co, W, mg, la, os, pr, re, ru, sr, sm, ta and B, and the molar content of cations in M' is w, 0<w/(a+x+y+j) is less than or equal to 0.1.
According to the invention, the source of the M element in the positive electrode material comprises the M 1 element in the precursor and the additive containing the M 2 element is introduced in the first sintering process.
According to the invention, the lithium source is at least one of lithium hydroxide, lithium carbonate and lithium nitrate;
According to the invention, the additive containing M 2 element is at least one selected from oxide, hydroxide, oxyhydroxide, phosphate, fluoride, boride and carbonate containing element M 2.
According to the present invention, the M 1 element, the M 2 element, and the M element are the same or different, and each is at least one element selected from Al, zr, nb, ti, Y, sc, cr, co, W, mg, la, os, pr, re, ru, sr, sm, ta and B.
According to the invention, the additive containing the element M 'is at least one selected from the group consisting of oxides, hydroxides, oxyhydroxides, phosphates, fluorides, borides, nitrides, carbonates and oxalates containing the element M'.
According to the invention, the molar ratio Li/(Ni+Mn+M 1+M2) of the amount of the lithium source to the sum of the amounts of the precursor and of the additive containing the element M 2 is 1 to 1.85, preferably 1 to 1.5.
According to the invention, the additive containing element M 2 is added in an amount of 0.0005 to 0.3, preferably 0.001 to 0.2, according to M 2/(Ni+Mn+M1+M2).
According to the invention, the molar ratio M '/(Ni+Mn+M 1+M2) of the additive amount containing the element M' to the primary sinter amount is from 0 to 0.1, preferably from 0.001 to 0.02.
According to the invention, when the Ni/Mn molar ratio is greater than 1, i.e., x/y >1, the relation between the first sintering temperature T 1 and Ni content satisfies that 550X (2-x) T 1 is 400X (3-x) C, the sintering time is 6 to 20 hours, preferably 8 to 15 hours.
According to the invention, when the Ni/Mn molar ratio is not more than 1, i.e., y/x is not less than 1, the relation between the first sintering temperature T 2 and Mn content satisfies 500X (1+y). Ltoreq.T 2≤650X (1+y). Ltoreq.C, the sintering time is 6 to 20 hours, preferably 8 to 15 hours.
According to the invention, when x is less than or equal to 0.5, the first and second sintering atmospheres are air, when x is less than or equal to 0.5 and less than or equal to 0.6, the first and second sintering atmospheres are air or air-oxygen mixture, and when x is less than or equal to 0.6, the first and second sintering atmospheres are oxygen or oxygen-air mixture.
The fourth aspect of the present invention provides a lithium-containing oxide cathode material prepared by the aforementioned method for preparing a lithium-containing oxide cathode material.
The fifth aspect of the invention provides a positive electrode sheet, wherein the positive electrode sheet comprises at least 90wt% of a lithium-containing oxide positive electrode material based on the total weight of the positive electrode sheet, and the lithium-containing oxide positive electrode material is the lithium-containing oxide positive electrode material.
According to the present invention, it is preferable that the positive electrode material mass ratio is not less than 95%.
According to the invention, the pole piece density of the positive pole piece is more than or equal to 2.8g/cm 3, preferably more than or equal to 3.2g/cm 3, and more preferably more than or equal to 3.5g/cm 3.
The sixth aspect of the invention provides an application of the lithium-containing oxide positive electrode material, the lithium-containing oxide positive electrode material precursor or the positive electrode sheet in a lithium ion battery.
The present invention will be described in detail by examples.
In the following examples and comparative examples:
unless otherwise specified, all raw materials are commercially available.
In the following examples, the properties referred to are obtained by:
(1) Phase test, which is to be obtained by testing an X-ray diffractometer of SmartLab kW model of Japanese physics company;
(2) Topography test, which is obtained by scanning electron microscope test of model S-4800 of Hitachi CHI, japan;
(3) Particle size test, namely, testing by a Marvern-company Hydro 2000mu type laser particle sizer;
(4) Specific surface area measured by a specific surface tester model TRISTAR II3020 of Micromertics in the united states;
(5) The tap density is obtained by testing a BT-30 tap density tester of the Baite company;
(6) The compaction density is obtained by testing a powder impedance tester of model MCP-PD51 of Mitsubishi chemical in Japan;
(7) Compression resistance index test, namely compressing a material under specific pressure by a 4350 type manual tablet press of Carver company in the United states, testing the particle size of the material after fracturing, substituting an compression resistance index formula, and calculating to obtain the material;
(8) Surface residual alkali test, namely titration measurement by a Metrohmm888 professional Tirando intelligent potentiometric titrator;
(9) The thermal stability test is carried out by testing through a thermogravimetric analysis tester of the model of the Metrele TGA-DSC 3;
(10) Electrochemical performance test:
The electrochemical performance of the prepared lithium-containing oxide positive electrode material is obtained by testing 2025 type button cells by adopting a new-Wei cell testing system, and specifically:
1) The 2025 type button cell is prepared by the following steps:
And (3) preparing a pole piece, namely fully mixing the lithium-containing oxide positive pole material, carbon black and polyvinylidene fluoride with a proper amount of N-methyl pyrrolidone according to a certain mass ratio to form uniform slurry, coating the uniform slurry on an aluminum foil, and drying, rolling and punching at 120 ℃ to prepare the positive pole piece with the diameter of 11 mm.
The assembled battery was fabricated using a Li metal plate having a diameter of 17mm and a thickness of 1mm as the negative electrode, a polyethylene porous film having a thickness of 25 μm as the separator, and an equal amount of a mixture of 1mol/L LiPF 6, ethylene Carbonate (EC) and diethyl carbonate (DEC) as the electrolyte.
And assembling the positive electrode plate, the diaphragm, the negative electrode plate and the electrolyte into a 2025 button cell in an Ar gas glove box with the water content and the oxygen content of less than 5ppm, and taking the cell at the moment as an unactivated cell.
2) Electrochemical performance test:
When the molar ratio of Ni/Mn is greater than 1, i.e., x/y >1, the button cell test conditions are that the button cell is left for 2 hours after being manufactured, after the open circuit voltage is stabilized, the battery is charged to a cut-off voltage of 4.3V in a manner that the current density of the positive electrode is 0.1C, and then the battery is charged at a constant voltage for 30 minutes, and then discharged to the cut-off voltage of 3.0V in the same manner, and the battery at this time is taken as an activated battery again for 1 time in the same manner. The method comprises the steps of using an activated battery to evaluate the charge and discharge capacity of a material in a voltage interval of 3.0-4.3V at 25 ℃ and a charge and discharge interval of 3.0-4.3V at 0.1C, using the activated battery to evaluate the rate capability of the material in a ratio of 1C capacity to 0.1C capacity in a charge and discharge test of 0.1C, 0.2C, 0.33C, 0.5C and 1C, and evaluating the cycle capability of the material in a 1C cycle of 80 times in a 3.0-4.4V interval.
When the mole ratio of Ni/Mn is not more than 1, that is, x/y is not more than 1, the button cell test condition is that the button cell is placed for 2 hours after the button cell is manufactured, after the open circuit voltage is stabilized, the button cell is charged to the cut-off voltage of 4.6V in a mode that the current density of the positive electrode is 0.1C, then the button cell is charged for 30 minutes under constant voltage, then the button cell is discharged to the cut-off voltage of 2.0V in the same current density, and the button cell is used as an activated cell in the same mode for 1 time. The charge and discharge capacity of the material is evaluated by using an activated battery in a voltage range of 2.0-4.6V, a charge and discharge range of 2.0-4.6V and a charge and discharge test at 0.1C, the rate performance of the material is evaluated by using a ratio of 1C capacity to 0.1C capacity and the cycle performance of the material is evaluated by using the activated battery in a charge and discharge test at 0.1C, 0.2C, 0.33C, 0.5C and 1C and by cycling at 0.0-4.6V for 80 times.
Example 1
This example is presented to illustrate a lithium oxide-containing positive electrode material prepared according to the present invention.
Nickel sulfate and manganese sulfate are dissolved according to a metal molar ratio of 5:3 to obtain a mixed salt solution with the concentration of 2mol/L, cobalt sulfate and aluminum sulfate are dissolved according to a metal molar ratio of Co/(Ni+Mn+Co+Al) =0.18 and Al/(Ni+Mn+Co+Al) =0.02 to obtain a mixed salt solution with the concentration of 2mol/L, sodium hydroxide is dissolved into an alkaline solution with the concentration of 6mol/L, and ammonia water is dissolved into a complexing agent solution with the concentration of 5 mol/L.
Then adding 20L of mixed salt solution, alkali solution and complexing agent solution into a reaction kettle in parallel flow mode together for reaction, keeping the stirring rotation speed at 600 revolutions per minute constant in the process, controlling the flow rate of the mixed salt solution at 300mL/h, controlling the reaction pH at 11.6, controlling the reaction temperature at 50 ℃, controlling the concentration of ammonia in a reaction system at 9g/L, carrying out reaction in N 2 gas, standing for 60h, carrying out solid-liquid separation and washing on slurry obtained by precipitation crystallization reaction at 500g/L, drying at 105 ℃ for 10h, and sieving to obtain a spherical Ni 0.5Mn0.3Co0.18Al0.02(OH)2 precursor material which is denoted as P-1.
The precursor P-1, lithium carbonate, additives TiO 2 and WO 3 are uniformly mixed in a high-speed mixer according to Li (Ni+Mn+Co+Al+Ti+W) =1.03, ti (Ni+Mn+Co+Al+Ti+W) =0.003, W (Ni+Mn+Co+Al+Ti+W) =0.002, and then the mixture is heated to 920 ℃ in an air atmosphere, kept for 10 hours, and naturally cooled to obtain a primary sintering anode material Li [ Li 0Ni0.4975Mn0.2985Co0.1791Al0.0199Ti0.003W0.002]O2, which is marked as S-1.
Uniformly mixing the primary sintering material S-1, additives Nb 2O5 and La 2O3 according to Nb (Ni+Mn+Co+Al+Ti+W) =0.002 and La (Ni+Mn+Co+Al+Ti+W) =0.002, heating to 650 ℃ in air atmosphere, maintaining for 6 hours, and naturally cooling to obtain the secondary sintering anode material Li[Li0Ni0.4975Mn0.2985Co0.1791Al0.0199Ti0.003W0.002]O2@Nb0.002La0.002, which is denoted as FS-1.
Examples 2 to 14
This example is presented to illustrate a lithium oxide-containing positive electrode material prepared according to the present invention.
A lithium-containing oxide cathode material was prepared in the same manner as in example 1, except that the precursor preparation process, the preparation process of the primary sintered cathode material, and the preparation process of the secondary sintered cathode material were different, as shown in table 1.
TABLE 1
Table 1 (subsequent)
Table 1 (subsequent)
In table 1, unless otherwise specified, the ratio and the amount ratio are molar ratios.
Comparative example 1
Using the same synthesis method and conditions as in example 5, only the first sintering temperature was adjusted to 600℃and the resulting cathode material was designated as D-1, as shown in Table 2.
Comparative example 2
Using the same synthesis method and conditions as in example 5, the first sintering temperature was adjusted to 900℃alone, and the resulting cathode material was designated as D-2, as shown in Table 2.
Comparative example 3
Using the same synthesis method and conditions as in example 5, the additives rhenium oxide and shirt were not added only in the preparation process of the primary sintered cathode material, and the resultant cathode material was designated as D-3, as shown in Table 2.
Comparative example 4
The same synthesis method and conditions as in example 5 were employed, and the obtained cathode material was designated as D-4 only in the preparation process of the secondary sintered cathode material without adding additives of tungsten nitride and aluminum fluoride, as shown in table 2.
Comparative example 5
Using the same synthesis method and conditions as in example 9, the solid content was adjusted to 150g/L only in the precursor preparation process, and the resulting positive electrode material was designated as D-5, as shown in Table 2.
Comparative example 6
Using the same synthesis method and conditions as in example 9, the additives tungsten oxide and aluminum oxyhydroxide were not added only in the preparation process of the primary sintered cathode material, and the resultant cathode material was designated as D-6, as shown in Table 2.
Comparative example 7
The same synthesis method and conditions as in example 9 were employed, except that the preparation process of the secondary sintered cathode material was removed, and the resultant cathode material was designated as D-7, as shown in table 2.
TABLE 2
Table 2 (subsequent)
Test example 1
The properties of the lithium-containing oxide positive electrode material precursors prepared in examples 1 to 14 and comparative examples 1 to 7 were tested, and the results are shown in Table 3, and the properties of the lithium-containing oxide positive electrode materials prepared in examples 1 to 14 and comparative examples 1 to 7 were tested, and the results are shown in tables 4 and 5.
TABLE 3 Table 3
TABLE 4 Table 4
Table 4 (subsequent)
Table 4 (subsequent)
TABLE 5
Test example 2
The lithium-containing oxide positive electrode materials prepared in examples 1 to 14 and comparative examples 1 to 7 were used as positive electrode sheets of lithium ion batteries, lithium ion batteries were prepared, and the performance of the lithium ion batteries was tested, and the results are shown in table 6.
TABLE 6
Lithium ion battery Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7
Pole piece density (g/cm 3) 3.2 3.2 3.5 3.4 3.6 3.3 3.5
0.1C discharge capacity (mAh/g) 173.1 181.3 192.3 208.7 225.2 228.3 233.5
1C discharge capacity (mAh/g) 158.6 167.1 176.5 192.2 214.3 216.2 218.5
1C Capacity/0.1C Capacity (%) 91.6 92.2 91.8 92.1 95.1 94.7 93.6
Capacity retention (%) 99.1 95.2 94.8 99.0 94.6 96.3 93.3
Watch 6 (subsequent)
Watch 6 (subsequent)
Lithium ion battery Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative example 5 Comparative example 6 Comparative example 7
Pole piece density (g/cm 3) 3.2 3.6 3.5 3.3 2.8 2.8 2.9
0.1C discharge capacity (mAh/g) 216.9 208.3 221.7 214.3 240.9 241.9 233.0
1C discharge capacity (mAh/g) 190.9 188.5 200.2 194.4 203.3 198.8 190.3
1C Capacity/0.1C Capacity (%) 88.0 90.5 90.3 90.7 84.4 82.2 81.7
Capacity retention (%) 86.7 85.9 87.5 86.6 88.0 89.0 89.9
In addition, in the present invention, FIG. 1 is a comparative schematic diagram of the charge and discharge curves of example 5 and comparative example 1, and it can be seen from FIG. 1 that the 0.1C discharge capacity (225.2 mAh/g) of the positive electrode material provided in example 5 is higher than the 0.1C discharge capacity (216.9 mAh/g) of the positive electrode material D-1 obtained when the first sintering temperature is too low (600 ℃), by the charge and discharge curves of comparative example 5 and comparative example 1.
Fig. 2 is a comparative schematic diagram of the cycle performance of example 5 and comparative example 1, and it can be seen from fig. 2 that the capacity retention rate (94.6%) of example 5 is significantly higher than that (86.7%) of the positive electrode material provided by D-1 by the cycle performance of comparative example 5 and comparative example 1. This is because, when the sintering temperature is too low, primary grain growth is not complete, resulting in low compressive index and unstable structure, and thus shows low capacity and cycle performance.
Fig. 3 is a comparative schematic diagram of charge and discharge curves of example 5 and comparative example 2, and it can be seen from fig. 3 that the 0.1C discharge capacity (225.2 mAh/g) of the positive electrode material provided in example 5 is higher than the 0.1C discharge capacity (208.3 mAh/g) of the positive electrode material D-2 obtained when the first sintering temperature is too high (900 ℃), by the charge and discharge curves of comparative example 5 and comparative example 2.
Fig. 4 is a comparative schematic diagram of the cycle performance of example 5 and comparative example 2, and it can be seen from fig. 4 that the capacity retention rate (94.6%) of example 5 is significantly higher than that (85.9%) of the positive electrode material provided by D-2 by the cycle performance of comparative example 5 and comparative example 2. This is because, when the sintering temperature is too high, primary grain growth is excessively developed, which also results in low compressive index and unstable structure, and thus exhibits low capacity and cycle performance.
Fig. 5 is a comparative schematic diagram of charge and discharge curves of example 5 and comparative example 3, and it can be seen from fig. 5 that the 0.1C discharge capacity (225.2 mAh/g) of example 5 is higher than the 0.1C discharge capacity (221.7 mAh/g) of the positive electrode material D-3 obtained when rhenium oxide and the sweater additive are not added in the first sintering, by the charge and discharge curves of comparative example 5 and comparative example 3.
Fig. 6 is a comparative graph of the cycle performance of example 5 and comparative example 3, and it can be seen from fig. 6 that the capacity retention rate (94.6%) of example 5 is significantly higher than that (87.5%) of the positive electrode material provided by D-3 by the cycle performance of comparative example 5 and comparative example 3. The above shows that the addition of rhenium oxide and the sweater oxide additive in the first sintering can improve the capacity, the cycle performance and the like of the material, because the proper doping modification can improve the micro-domain structure of the material and form lithium-containing compounds on the surfaces of particles or among the particles, the compression index of the material can be improved, and the capacity, the cycle performance and other electrochemical performances of the positive electrode material can be improved.
Fig. 7 is a comparative schematic diagram of charge and discharge curves of example 5 and comparative example 4, and it can be seen from fig. 7 that the 0.1C discharge capacity (225.2 mAh/g) of example 5 is significantly higher than the 0.1C discharge capacity (214.3 mAh/g) of the positive electrode material D-4 obtained when the tungsten nitride and aluminum fluoride additives were not added in the second sintering, by the charge and discharge curves of comparative example 5 and comparative example 4.
Fig. 8 is a comparative graph of the cycle performance of example 5 and comparative example 4, and it can be seen from fig. 8 that the capacity retention rate (94.6%) of example 5 is significantly higher than that (86.6%) of the positive electrode material provided by D-4 by the cycle performance of comparative example 5 and comparative example 4. The above shows that the addition of the tungsten nitride and aluminum fluoride additives in the second sintering can improve the capacity, the cycle performance and the like of the material, because a stable coating layer can be formed on the surface of the material, the surface micro-area structure of the material is improved, the surface side reaction of the material is reduced, and the compression index of the material is also improved, so that the capacity, the cycle performance and other electrochemical performances of the positive electrode material are improved.
Fig. 9 is a comparative schematic diagram of charge and discharge curves of example 9 and comparative example 5, and it can be seen from fig. 9 that the 0.1C discharge capacity (250.7 mAh/g) of example 9 is significantly higher than the 0.1C discharge capacity (240.9 mAh/g) of the positive electrode material D-5 obtained when the solid content is reduced to 150g/L in the precursor preparation process, by the charge and discharge curves of comparative example 9 and comparative example 5.
Fig. 10 is a comparative graph of the cycle performance of example 9 and comparative example 5, and it can be seen from fig. 10 that the capacity retention rate (93.9%) of example 9 is significantly higher than that (88.0%) of the positive electrode material provided by D-5 by the cycle performance of comparative example 9 and comparative example 5. This is because a low solid content results in poor crystallinity and compactness of the precursor and changes in morphology and microstructure, and thus exhibits a low compressive index, resulting in deterioration of electrochemical properties such as capacity and cycle performance of the material.
Fig. 11 is a comparative schematic diagram of charge and discharge curves of example 9 and comparative example 6, and it can be seen from fig. 11 that the 0.1C discharge capacity (250.7 mAh/g) of example 9 is significantly higher than the 0.1C discharge capacity (241.9 mAh/g) of the positive electrode material D-6 obtained when the tungsten oxide and the aluminum oxyhydroxide additives were not added in the first sintering, by the charge and discharge curves of comparative example 9 and comparative example 6.
Fig. 12 is a comparative graph of the cycle performance of example 9 and comparative example 6, and it can be seen from fig. 12 that the capacity retention rate (93.9%) of example 9 is significantly higher than that (89.0%) of the positive electrode material provided by D-6 by the cycle performance of comparative example 9 and comparative example 6. The above shows that the addition of the tungsten oxide and the aluminum oxyhydroxide additives to the first sintering can improve the capacity, cycle performance, and the like of the material, because the appropriate doping modification can improve the micro-domain structure of the material and form lithium-containing compounds on the particle surfaces or among the particles, both contribute to improving the compressive index of the material, and thus improve the capacity, cycle performance, and other electrochemical properties of the cathode material.
Fig. 13 is a comparative schematic diagram of charge and discharge curves of example 9 and comparative example 7, and it can be seen from fig. 13 that the 0.1C discharge capacity (250.7 mAh/g) of example 9 is significantly higher than the 0.1C discharge capacity (233.0 mAh/g) of the positive electrode material D-7 obtained without the second sintering process, by the charge and discharge curves of comparative example 9 and comparative example 7.
Fig. 14 is a comparative graph of the cycle performance of example 9 and comparative example 7, and it can be seen from fig. 14 that the capacity retention rate (93.9%) of example 9 is significantly higher than that (89.9%) of the positive electrode material provided by D-7 by the cycle performance of comparative example 9 and comparative example 7. The above shows that the second sintering can effectively improve the capacity, the cycle performance and the like of the material, because the second sintering process can form a stable coating layer on the surface of the material and rearrange atoms on the surface of the material, improve the surface micro-area structure of the material, reduce the surface side reaction of the material and improve the compression index of the material, thereby improving the electrochemical performances such as the capacity, the cycle performance and the like of the positive electrode material.
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 (18)

1. A lithium-containing oxide positive electrode material is characterized in that the compressive index delta lambda (P 100) of the positive electrode material meets the conditions that delta lambda (P 100) is more than or equal to 60% + (y/x) multiplied by 5%;
wherein y/x is the molar ratio of Mn/Ni in the positive electrode material;
The compressive index Δλ (P 100) is calculated by the following steps:
Wherein the method comprises the steps of Refers to the value of the particle accumulation distribution D 5 of the material under the condition of no external mechanical pressure in the natural state, namely P=0 Mpa,Refers to the value of the particle cumulative distribution D 5 of the material at p=100 Mpa, and D 5 refers to the particle size value at which the particle cumulative volume distribution is 5%;
wherein the lithium-containing oxide positive electrode material has a chemical formula shown in formula (3):
Li [ Li aNixMnyMj]O2 @ M', formula (3);
Wherein a is more than or equal to 0 and less than or equal to 0.3, x is more than or equal to 0.2 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 0.75, j is more than or equal to 0 and less than or equal to 0.35, M is at least one element selected from Al, zr, nb, ti, Y, sc, cr, co, W, mg, la, os, pr, re, ru, sr, sm, ta and B, M 'is oxide, phosphide, sulfide, fluoride or chloride containing at least one element of Al, zr, nb, ti, Y, sc, cr, co, W, mg, la, os, pr, re, ru, sr, sm, ta and B, and the molar content of cations in M' is w, 0<w/(a+x+y+j) is more than or equal to 0.1.
2. The lithium-containing oxide positive electrode material according to claim 1, wherein the positive electrode material has a compressive index Δλ (P 200) satisfying Δλ (P 200) > 45++ (y/x) ×5%;
And/or the compressive index Deltalambda (P 300) of the positive electrode material satisfies Deltalambda (P 300) not less than 35++ (y/x) x 5%.
3. The lithium-containing oxide positive electrode material according to claim 1, wherein 0.02≤a≤0.2, 0.3< x <0.9,0.05< y≤0.68, 0< j≤0.3, 0.001< w/(a+x+y+j). Ltoreq.0.02, M is at least one element selected from Zr, nb, ti, Y, sc, cr, co, W, mg, la, ta and B, and M' is an oxide, phosphide, sulfide or fluoride containing at least one element selected from Zr, nb, ti, Y, sc, cr, co, W, mg, la, ta and B.
4. The lithium-containing oxide positive electrode material according to any one of claims 1 to 3, wherein the compacted density of the lithium-containing oxide positive electrode material is not less than 2.8g/cm 3;
And/or the tap density of the lithium-containing oxide positive electrode material is more than or equal to 1.7g/cm 3;
and/or the content of the surface soluble alkali of the lithium-containing oxide positive electrode material meets the following conditions:
Li2CO3≤1wt%,LiOH≤0.5wt%;
and/or the number of the groups of groups,
The full width at half maximum FWHM (003) of the (003) crystal face and the full width at half maximum FWHM (104) of the (104) crystal face obtained by XRD of the lithium-containing oxide positive electrode material satisfy the following conditions:
0.10≤FWHM(003)≤0.25;
0.20≤FWHM(104)≤0.50;
and/or the number of the groups of groups,
The peak areas S (003) and S (104) of the (003) crystal faces and the (104) crystal faces obtained by XRD of the lithium-containing oxide positive electrode material meet the following conditions:
1.1≤S(003)/S(104)≤1.8。
5. The lithium-containing oxide positive electrode material according to claim 4, wherein the compacted density of the lithium-containing oxide positive electrode material is 3g/cm 3 or more;
And/or the tap density of the lithium-containing oxide positive electrode material is more than or equal to 2g/cm 3;
and/or the content of the surface soluble alkali of the lithium-containing oxide positive electrode material meets the following conditions:
Li2CO3≤0.5wt%,LiOH≤0.4wt%;
and/or the number of the groups of groups,
The full width at half maximum FWHM (003) of the (003) crystal face and the full width at half maximum FWHM (104) of the (104) crystal face obtained by XRD of the lithium-containing oxide positive electrode material satisfy the following conditions:
0.13≤FWHM(003)≤0.22;
0.22≤FWHM(104)≤0.42;
and/or the number of the groups of groups,
The peak areas S (003) and S (104) of the (003) crystal faces and the (104) crystal faces obtained by XRD of the lithium-containing oxide positive electrode material meet the following conditions:
1.2≤S(003)/S(104)≤1.6。
6. The lithium-containing oxide positive electrode material according to claim 5, wherein the compacted density of the lithium-containing oxide positive electrode material is 3.2g/cm 3 or more;
And/or the tap density of the lithium-containing oxide positive electrode material is more than or equal to 2.4g/cm 3;
and/or the content of the surface soluble alkali of the lithium-containing oxide positive electrode material meets the following conditions:
Li2CO3≤0.3wt%,LiOH≤0.3wt%。
7. the lithium-containing oxide positive electrode material according to claim 6, wherein the content of the surface-soluble alkali of the lithium-containing oxide positive electrode material satisfies the following condition:
Li2CO3≤0.2wt%,LiOH≤0.2wt%。
8. A lithium-containing oxide positive electrode material precursor is characterized in that the compressive index delta lambda '(P 50) of the precursor meets the conditions that delta lambda' (P 50) is more than or equal to 35% + (v/u) multiplied by 8%;
wherein v/u is the molar ratio of Mn/Ni in the precursor;
The compressive index Δλ' (P 50) of the precursor is calculated as follows:
Wherein the method comprises the steps of Refers to the value of the particle accumulation distribution D 5 of the precursor material under the condition of no external mechanical pressure in the natural state, namely P=0 MPa,Refers to the value of the particle cumulative distribution D 5 of the precursor material at p=50 MPa, and D 5 refers to the particle size value at which the particle cumulative volume distribution is 5%;
wherein the precursor has a chemical formula shown in formula (1):
Ni uMnvM1γ(OH)2, formula (1);
Wherein u+v+γ=1, 0.2< u <1,0< v≤ 0.75,0≤γ≤0.35, and m 1 is at least one element selected from Al, zr, nb, ti, Y, sc, cr, co, W, mg, na, la, os, pr, re, ru, sr, sm, ta and B.
9. The precursor according to claim 8, wherein the precursor has a compressive index Δλ '(P 100) satisfying Δλ' (P 100) > 25++ (v/u) x 8%.
10. A method for preparing the lithium-containing oxide positive electrode material according to any one of claims 1 to 7, characterized in that the method comprises:
s1, uniformly mixing a precursor with a chemical formula shown in a formula (1), a lithium source and an optional additive containing an element M 2, and performing primary sintering in an atmosphere furnace to obtain a primary sintering material with a chemical formula shown in a formula (2);
s2, uniformly mixing the primary sintering material with an additive containing an element M', and performing secondary sintering on the mixed material in an atmosphere furnace to obtain a lithium-containing metal oxide with a chemical formula shown in a formula (3);
Ni uMnvM1γ(OH)2, formula (1);
Wherein u+v+γ=1, 0.2< u <1,0< v≤ 0.75,0≤γ≤0.35, m 1 is at least one element selected from Al, zr, nb, ti, Y, sc, cr, co, W, mg, na, la, os, pr, re, ru, sr, sm, ta and B;
Li [ Li aNixMnyMj]O2 ], formula (2);
Li [ Li aNixMnyMj]O2 @ M', formula (3);
wherein, in the formula (2) and the formula (3):
a+x+y+j=1,0≤a≤0.3,0.2<x<1,0<y≤0.75,0<j≤0.35;
M comprises M 1 element in the precursor, and M 2 element is introduced in the first sintering process;
m 1、M2, which are the same or different, are each at least one element selected from Al, zr, nb, ti, Y, sc, cr, co, W, mg, la, os, pr, re, ru, sr, sm, ta and B;
In formula (3):
M 'is oxide, phosphide, sulfide, fluoride or chloride containing at least one element of Al, zr, nb, ti, Y, sc, cr, co, W, mg, la, os, pr, re, ru, sr, sm, ta and B, and the molar content of cations in M' is w, 0<w/(a+x+y+j) is less than or equal to 0.1.
11. The production method according to claim 10, wherein when the molar ratio of Ni/Mn is greater than 1, i.e., x/y >1, the relation between the sintering temperature T 1 and Ni content of the first sintering satisfies 550X (2-x). Ltoreq.T 1≤400X (3-x) ° C, the sintering time is 6 to 20 hours;
And/or when the mole ratio of Ni/Mn is less than or equal to 1, namely y/x is more than or equal to 1, the relation between the sintering temperature T 2 and Mn content of the first sintering is met, wherein the sintering temperature T is 500X (1+y) less than or equal to T 2 less than or equal to 650X (1+y) DEG C, and the sintering time is 6-20h;
And/or when x is less than or equal to 0.5, the first and second sintering atmospheres are air, when x is less than or equal to 0.5 and less than or equal to 0.6, the first and second sintering atmospheres are air or a mixture of air and oxygen, and when x is less than or equal to 0.6, the first and second sintering atmospheres are oxygen or a mixture of oxygen and air.
12. The preparation method according to claim 11, wherein the relation between the sintering temperature T 1 and the Ni content of the first sintering is satisfied that the sintering time is 8-15h;
And/or when the mole ratio of Ni/Mn is less than or equal to 1, namely y/x is more than or equal to 1, the relation between the sintering temperature T 2 of the first sintering and the Mn content is satisfied, and the sintering time is 8-15h.
13. A lithium-containing oxide positive electrode material produced by the method for producing a lithium-containing oxide positive electrode material according to any one of claims 10 to 12.
14. A positive electrode sheet comprising at least 90wt% of a lithium-containing oxide positive electrode material, based on the total weight of the positive electrode sheet;
Wherein the lithium-containing oxide positive electrode material is the lithium-containing oxide positive electrode material according to any one of claims 1 to 7 and 13.
15. The positive electrode sheet of claim 14, wherein the sheet density of the positive electrode sheet is ≡2.8g/cm 3.
16. The positive electrode sheet of claim 15, wherein the positive electrode sheet has a sheet density of ≡3.2g/cm 3.
17. The positive electrode sheet of claim 16, wherein the positive electrode sheet has a sheet density of ≡3.5g/cm 3.
18. Use of the lithium-containing oxide positive electrode material according to any one of claims 1 to 7 and 13, the lithium-containing oxide positive electrode material precursor according to claim 8 or 9 or the positive electrode sheet according to any one of claims 14 to 17 in a lithium ion battery.
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