CN113161526A - Positive electrode material and preparation method and application thereof - Google Patents

Positive electrode material and preparation method and application thereof Download PDF

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Publication number
CN113161526A
CN113161526A CN202110437212.6A CN202110437212A CN113161526A CN 113161526 A CN113161526 A CN 113161526A CN 202110437212 A CN202110437212 A CN 202110437212A CN 113161526 A CN113161526 A CN 113161526A
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positive electrode
sintering
electrode material
mixing
aluminum
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杨元婴
孙化雨
朱呈岭
汪东煌
其他发明人请求不公开姓名
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Envision Power Technology Jiangsu Co Ltd
Envision Ruitai Power Technology Shanghai Co Ltd
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Envision Power Technology Jiangsu Co Ltd
Envision Ruitai Power Technology Shanghai 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
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • 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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • 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 provides a positive electrode material and a preparation method and application thereof, wherein the preparation method comprises the following steps: (1) taking a hydroxide precursor of nickel, cobalt and manganese, and sintering for the first time to obtain a sintered material; (2) mixing the calcined material obtained in the step (1) with aluminum-doped zinc oxide (AZO) to obtain a mixture; (3) and (3) carrying out secondary sintering on the mixture obtained in the step (2) to obtain the cathode material. According to the invention, the AZO coating layer is coated on the surface of the ternary positive electrode material, so that good ionic conductivity and electronic conductivity are provided on the surface of the positive electrode material, the dynamic performance of the material is improved, and the long-term cycling stability and the rate capability of the ternary positive electrode under high voltage are obviously improved.

Description

Positive electrode material and preparation method and application thereof
Technical Field
The invention belongs to the field of lithium ion batteries, and relates to a positive electrode material, and a preparation method and application thereof.
Background
Nickel-cobalt-manganese ternary layered material LiNixCoyMn1-x-yO2By virtue of higher theoretical capacity and high reaction platform voltage, the lithium ion battery is the first choice of a power battery system with high energy density. The current commercial ternary material battery has working voltage of about 4.2-4.35V and insufficient utilization rate of reversible lithium. In order to further improve the volumetric energy density of the ternary battery, the charging voltage needs to be increased. However, when the charging voltage exceeds 4.4V, irreversible structural changes occur in the cathode material due to thermodynamic instability of the layered structure in the highly delithiated state and degradation of the cathode/electrolyte interface performance due to surface side reactions, and the electrochemical performance of the battery will be drastically degraded with accelerated loss of capacity.
CN109742393A discloses a preparation method of an NCM811 type ternary material, which comprises the following steps: (1) preparation of ternary material precursor Ni by coprecipitation method0.8Co0.1Mn0.1(OH)2(ii) a (2) Heating the ternary material precursor, and uniformly mixing the obtained product with a lithium source to obtain raw material mixed powder; (3) sintering the raw material mixed powder in an oxygen atmosphere, crushing twice, and washing to obtain a positive electrode substrate; (4) mixing the positive electrode base material with the zirconium source coating solution to obtain positive electrode slurry; (5) and drying, sintering, crushing, homogenizing, removing iron and screening the positive electrode slurry to obtain a finished product. The NCM811 type ternary material obtained by the preparation method has the advantages of stable chemical structure, good electrical property and safe and reliable preparation method, can be suitable for large-scale production, creates conditions for popularization and application of the high-nickel ternary material, and can meet the development requirement of the market, but the prepared ternary materialThe specific capacity is lower.
CN108987696A discloses a lithium-rich manganese-based composite ternary cathode material and a preparation method thereof, the charging voltage of the lithium-rich manganese-based material can reach about 4.8V, and in the process of Li extraction from LiMO, LiMnO can supplement Li to maintain the stability of the material structure, so that the lithium-rich manganese and the ternary material can be considered to be compounded, the coulombic efficiency of the silicon carbon of the cathode is effectively improved, and the purposes of supplementing enough lithium source through the lithium-rich manganese, compensating the lithium consumed by the cathode in the process of forming an SEI film and improving the charging and discharging efficiency of the cathode are achieved. However, in the long-term charge-discharge use process of the prepared battery cell, new SEI films are continuously generated along with the progress of side reactions of the electrolyte, side reactions and continuous growth of lithium dendrites are continuously generated at the interface, and the cycle stability and the rate capability of the battery cell are seriously influenced.
The scheme has the problems of poor cycle performance, poor rate capability or low specific capacity and the like, so that the development of the cathode material with good cycle performance and rate capability and high specific capacity for the lithium ion battery is necessary.
Disclosure of Invention
The invention aims to provide a positive electrode material and a preparation method and application thereof, wherein the preparation method comprises the following steps: (1) taking a hydroxide precursor of nickel, cobalt and manganese, and sintering for the first time to obtain a sintered material; (2) mixing the calcined material obtained in the step (1) with aluminum-doped zinc oxide (AZO) to obtain a mixture; (3) and (3) carrying out secondary sintering on the mixture obtained in the step (2) to obtain the cathode material. According to the invention, the AZO coating layer is coated on the surface of the ternary positive electrode material, so that good ionic conductivity and electronic conductivity are provided on the surface of the positive electrode material, the dynamic performance of the material is improved, and the long-term cycling stability and the rate capability of the ternary positive electrode under high voltage are obviously improved.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a method for preparing a positive electrode material, comprising the steps of:
(1) taking a hydroxide precursor of nickel, cobalt and manganese, and sintering for the first time to obtain a sintered material;
(2) mixing the calcined material obtained in the step (1) with aluminum-doped zinc oxide (AZO) to obtain a mixture;
(3) and (3) carrying out secondary sintering on the mixture obtained in the step (2) to obtain the cathode material.
According to the invention, the AZO coating layer is coated on the surface of the ternary positive electrode material, so that good ionic conductivity and electronic conductivity are provided on the surface of the positive electrode material, the dynamic performance of the material is improved, and the long-term cycling stability and the rate capability of the ternary positive electrode under high voltage are obviously improved.
Preferably, the chemical formula of the hydroxide precursor of nickel, cobalt and manganese in the step (1) is Li2NixCoyMn1-x-y(OH)2，0<x<1, for example: 0.1, 0.2, 0.5, 0.7 or 0.9 etc., 0<y<1, for example: 0.1, 0.2, 0.5, 0.7, or 0.9, etc.
Preferably, the temperature of the primary sintering in the step (1) is 300-1000 ℃, for example: 300 deg.C, 400 deg.C, 500 deg.C, 600 deg.C, 700 deg.C, 800 deg.C, 900 deg.C or 1000 deg.C etc.
Preferably, the time of the primary sintering in the step (1) is 0.5-9 h, for example: 0.5h, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h or 9h and the like.
Preferably, the oxygen concentration of the primary sintering in the step (1) is 50-99.9 vol%, for example: 50 vol%, 60 vol%, 70 vol%, 80 vol%, 90 vol%, 99.9 vol%, or the like.
Preferably, ZnO and Al in the aluminum-doped zinc oxide in the step (2)2O3The mass ratio of (10-99) to (1), for example: 10:1, 20:1, 30:1, 50:1, 80:1, or 99:1, etc.
Preferably, the mass ratio of the calcined material to the aluminum-doped zinc oxide is 1 (0.002-0.05), such as: 1:0.002, 1:0.008, 1:0.01, 1:0.03 or 1:0.05, etc.
Preferably, the mixing comprises dry and/or wet mixing.
Preferably, the dry mixing has a stirring frequency of 20 to 100Hz, such as: 20Hz, 40Hz, 50Hz, 60Hz, 80Hz or 100Hz, etc.
Preferably, the dry mixing time is 5-120 min, for example: 5min, 10min, 20min, 50min, 80min, 100min or 120min and the like.
Preferably, the wet-mixed solvent comprises ethanol.
Preferably, the wet mixing is stirred until the solvent is completely volatilized.
Preferably, the temperature of the secondary sintering in the step (3) is 100-800 ℃, for example: 100 ℃, 300 ℃, 500 ℃, 600 ℃, 800 ℃ or the like.
Preferably, the time of the secondary sintering in the step (3) is 0.5-10 h, for example: 0.5h, 1h, 2h, 3h, 5h, 7h or 10h and the like.
Preferably, the oxygen concentration of the secondary sintering in the step (3) is 0-99.9 vol%, for example: 1 vol%, 5 vol%, 10 vol%, 20 vol%, 50 vol%, 99.9 vol%, or the like.
As a preferable scheme of the invention, the preparation method comprises the following steps:
(1) taking a hydroxide precursor of nickel, cobalt and manganese, and sintering for 0.5-9 h under the conditions that the temperature is 300-1000 ℃ and the oxygen concentration is 50-99.9 vol% to obtain a primary sintered material;
(2) mixing the calcined material obtained in the step (1) with nano-scale aluminum-doped zinc oxide to obtain a mixture;
(3) and (3) sintering the mixture obtained in the step (2) for 0.5-10 h at the temperature of 100-800 ℃ and under the oxygen concentration of 0-99.9 vol% to obtain the cathode material.
In a second aspect, the present invention provides a positive electrode material produced by the production method according to the first aspect.
Preferably, the cathode material comprises a ternary cathode material and an aluminum-doped zinc oxide coating layer coated on the surface of the ternary cathode material.
In a third aspect, the invention provides a positive electrode plate, which comprises the positive electrode material as described in the second aspect.
In a fourth aspect, the invention further provides a lithium ion battery, where the lithium ion battery includes the positive electrode sheet described in the third aspect.
Compared with the prior art, the invention has the following beneficial effects:
(1) according to the invention, the AZO coating layer is coated on the surface of the ternary positive electrode material, so that good ionic conductivity and electronic conductivity are provided on the surface of the positive electrode material, the dynamic performance of the material is improved, and the long-term cycling stability and the rate capability of the ternary positive electrode under high voltage are obviously improved.
(2) The first gram capacity of discharge of a battery prepared by using the anode material can reach more than 175.5mAh/g, the capacity retention rate can reach more than 69.5% after 80 cycles, the Rct can reach less than 106m omega after 80 cycles, the first gram capacity of discharge of the battery prepared by using the anode material can reach 181.2mAh/g, the capacity retention rate can reach more than 96.4% after 80 cycles, and the Rct can reach less than 20m omega after 80 cycles by adjusting the mass ratio of the primary sintering material to the aluminum-doped zinc oxide and the secondary sintering temperature.
Drawings
Fig. 1 is an XRD comparison pattern of the positive electrode materials described in example 1 and comparative example 1.
Fig. 2 is a surface morphology SEM image of the positive electrode material described in example 1.
Fig. 3 is a graph comparing the cycle performance of batteries manufactured using the positive electrode materials described in example 1 and comparative example 1.
Fig. 4 is a graph comparing rate performance of batteries manufactured using the cathode materials described in example 1 and comparative example 1.
Fig. 5 is a comparative graph of EIS testing before cycling of batteries made using the positive electrode materials described in example 1 and comparative example 1.
Fig. 6 is a comparative graph of EIS testing after cycling of batteries fabricated using the positive electrode materials described in example 1 and comparative example 1.
Detailed Description
The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.
Example 1
The embodiment provides a positive electrode material, and a preparation method of the positive electrode material comprises the following steps:
(1) placing the 811 precursor in a furnace to calcine for 4 hours, wherein the sintering temperature is 975 ℃, and the oxygen concentration is 95 vol% to obtain a primary sintered material;
(2) 100g of calcined material was pulverized and mixed with 1g of nanoscale AZO (ZnO and Al)2O3The mass ratio of (A) to (B) is 95: 1) mixing the powders, dissolving in ethanol, and stirring until ethanol is completely volatilized to obtain wet mixture;
(3) and (3) placing the wet mixture obtained in the step (2) into a furnace to be calcined for 10 hours at the sintering temperature of 500 ℃ to obtain the cathode material.
The surface morphology SEM image of the positive electrode material is shown in fig. 2, and it can be seen from fig. 2 that the surface of the positive electrode material particles is uniformly covered with AZO, and the surface morphology becomes rough. The size of the coating was about 10nm, close to the diameter of the AZO nanoparticles. To determine the composition of the coating, the distribution of the elements on the surface of the positive electrode particles was studied using EDS. EDS analysis showed that the zinc element was uniformly distributed over the surface of the particles in selected areas. Due to the low content, the signal of Al is weak, but is identical with the region of zinc element distribution.
Example 2
(1) Placing the 811 precursor in a furnace to calcine for 3h, wherein the sintering temperature is 950 ℃, and the oxygen concentration is 85 vol%, so as to obtain a primary sintering material;
(2) 100g of calcined material was pulverized and mixed with 0.3g of nano-sized AZO (ZnO and Al)2O3The mass ratio of (A) to (B) is 90: 1) mixing the powders, mixing for 30min in a ribbon blender using a frequency of 35HZ to obtain a dry mix;
(3) and (3) placing the dry-process mixture obtained in the step (2) into a furnace to calcine for 5 hours, wherein the sintering temperature is 500 ℃, and thus the anode material is obtained.
Example 3
This example differs from example 1 only in that the AZO in step (2) has a mass of 4g and the other conditions and parameters are exactly the same as in example 1.
Example 4
This example differs from example 1 only in that the AZO in step (2) has a mass of 0.1g and the other conditions and parameters are exactly the same as those in example 1.
Example 5
This example differs from example 1 only in that the AZO in step (2) has a mass of 6g and the other conditions and parameters are exactly the same as in example 1.
Example 6
This example is different from example 1 only in that the sintering temperature in step (3) is 100 ℃, and other conditions and parameters are exactly the same as those in example 1.
Example 7
This example is different from example 1 only in that the sintering temperature in step (3) is 800 ℃, and other conditions and parameters are exactly the same as those in example 1.
Comparative example 1
The present comparative example provides a positive electrode material, which is prepared by the following method:
(1) placing the 811 precursor in a furnace to calcine for 4h, wherein the sintering temperature is 975 ℃, and the oxygen concentration is 95%, so as to obtain a primary sintering material;
(2) and (3) crushing 100g of the calcined material, and then calcining the crushed calcined material in a furnace for 10 hours at the sintering temperature of 250 ℃ to obtain the cathode material.
And (3) performance testing:
the positive electrode materials obtained in examples 1 to 7 and comparative example 1 were mixed with conductive carbon black (Super P), conductive carbon tubes (CNT) and polyvinylidene fluoride (PVDF) at a mass ratio of 97: 1: 1: 1 into N-methyl pyrrolidone (NMP), stirring at high speed to obtain slurry with certain viscosity, coating the slurry on aluminum foil, placing in a vacuum oven, and oven drying at 60 deg.C for 12 hr to obtain the final product with surface density of 18g/cm2The dried pole piece is rolled, and the compaction density is 3.4g/cm3And cutting the pole piece, and assembling the button cell by taking lithium metal as a negative electrode and taking a lithium hexafluorophosphate solution as an electrolyte.
The cycle test method comprises the following steps:
the flow is set on the test equipment, Xinwei tester, and the test current: 0.1C, constant current and constant voltage charging, 0.1C constant current discharging, and the cut-off condition of the constant voltage section: 50uA, voltage: 3.0-4.45V. The process is circulated 80 times.
EIS test method:
the cathode and the lithium sheet are assembled into a 2016 button Cell, EIS is tested after full charge, a solarran analytical 1470E Cell Test System type electrochemical workstation is adopted, the Test condition amplitude is 5mv, the frequency range is 0.01-100000 Hz, and the Test result is shown in Table 1:
TABLE 1
Figure BDA0003033616160000081
Figure BDA0003033616160000091
As can be seen from Table 1, the initial gram-discharge capacity of the battery prepared from the cathode material can reach more than 175.5mAh/g, the capacity retention rate after 80 cycles can reach more than 69.5%, the Rct after 80 cycles can reach less than 106m omega, the initial gram-discharge capacity of the battery prepared from the cathode material can reach 181.2mAh/g, the capacity retention rate after 80 cycles can reach more than 96.4%, and the Rct after 80 cycles can reach less than 20m omega by adjusting the mass ratio of the primary sintering material to the aluminum-doped zinc oxide and the secondary sintering temperature.
Compared with the examples 2 to 5, the mass ratio of the calcined material to the aluminum-doped zinc oxide influences the performance of the prepared cathode material, and the mass ratio of the calcined material to the aluminum-doped zinc oxide is controlled to be 1: (0.002-0.5) can be used for preparing the positive electrode material with better effect. If the mass ratio of the primary sintering material to the aluminum-doped zinc oxide is more than 1:0.002, the formed coating layer is not uniform, and a stable surface and a CEI film cannot be established; if the mass ratio of the primary sintered material to the aluminum-doped zinc oxide is less than 1:0.5, the formed coating layer is too thick, so that the lithium ion can be inhibited from being removed, and the gram capacity is greatly reduced.
Compared with the examples 6 to 7, the performance of the prepared cathode material is also affected by the secondary sintering temperature, and if the secondary sintering temperature is lower than 100 ℃, the AZO can not be coated on the surface of the material, so that the formed cathode material is not coated; if the secondary sintering temperature is higher than 800 ℃, the coating layer diffuses and permeates into the material, so that the lithium ion transmission and migration are influenced, and the capacity and the cycle performance are deteriorated.
Compared with the comparative example 1, the invention has the advantages that the AZO coating layer is coated on the surface of the ternary positive electrode material, so that the good ionic conductivity and electronic conductivity are provided on the surface of the positive electrode material, the dynamic performance of the material is improved, and the long-term cycling stability and rate capability of the ternary positive electrode under high voltage are obviously improved.
The XRD contrast patterns of the cathode materials described in the example 1 and the comparative example 1 are shown in figure 1, and as can be seen from figure 1, the XRD patterns of the cathode materials described in the example 1 are basically unchanged relative to the XRD patterns of the comparative example 1, and are all typical hexagonal alpha-NaFeO2And the structure shows that the coating of the AZO does not damage the crystal structure of the ternary cathode material. Example 1 no new impurity peak appeared, indicating that the amount of coating was small and insufficient to produce a diffraction peak.
The comparison of the cycle performance of the batteries manufactured by using the positive electrode materials described in example 1 and comparative example 1 is shown in fig. 3, and it can be seen from fig. 3 that the first discharge capacity of the ternary positive electrode material not coated with aluminum-doped zinc oxide is 181.2mAh/g, and the first discharge capacity is 180.8mAh/g after being coated with aluminum-doped zinc oxide, which are substantially the same, indicating that the first discharge capacity is not affected by the coating. Under high voltage, the capacity attenuation of the uncoated positive electrode material is fast, the capacity retention rate is only 78% after 80 cycles, the capacity retention rate of the coated aluminum-doped zinc oxide ternary positive electrode material is more than 95% after 80 cycles, and the cycle performance is greatly improved.
A graph comparing the rate performance of the batteries manufactured by using the positive electrode materials described in example 1 and comparative example 1 is shown in fig. 4, and it can be seen from fig. 4 that the capacity retention rate of the positive electrode material coated with aluminum-doped zinc oxide at a large rate is also improved compared to that of the uncoated material.
Comparative graphs of EIS tests before and after cycling of batteries manufactured using the cathode materials described in example 1 and comparative example 1 are shown in fig. 5 to 6, and it can be seen from fig. 5 to 6 that the nyquist plot of EIS consists of three regions including a high-frequency semicircle representing the surface film resistance Rf of a cathode and a metallic lithium cathode manufactured using a ternary cathode material; a mid-frequency half circle representing the positive charge transfer resistance Rct, and a Warburg impedance at low frequency. There was no significant difference in impedance before cycling; after 80 cycles, the impedance increased, with a clear distinction. In the high frequency region, the Rf value of the AZO clad material is significantly reduced, about one-half of that of the uncoated material, indicating a thinner and more porous SEI/CEI layer. At intermediate frequencies, the Rct of the uncoated positive electrode material is high (88 Ω), meaning that detrimental decomposition occurs at the positive electrode/electrolyte interface, resulting in increased polarization and reduced capacity. After the AZO coating is coated, the cyclic degradation is obviously inhibited, and the Rct is reduced to one fourth of the original value (20 omega).
The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.

Claims (10)

1. A preparation method of a positive electrode material is characterized by comprising the following steps:
(1) taking a hydroxide precursor of nickel, cobalt and manganese, and sintering for the first time to obtain a sintered material;
(2) mixing the calcined material obtained in the step (1) with aluminum-doped zinc oxide to obtain a mixture;
(3) and (3) carrying out secondary sintering on the mixture obtained in the step (2) to obtain the cathode material.
2. The method of claim 1, wherein the hydroxide precursor of nickel-cobalt-manganese in step (1) has a chemical formula of Li2NixCoyMn1-x-y(OH)2，0<x<1，0<y<1；
Preferably, the temperature of the primary sintering in the step (1) is 300-1000 ℃;
preferably, the time of the primary sintering in the step (1) is 0.5-9 h;
preferably, the oxygen concentration of the primary sintering in the step (1) is 50-99.9 vol%.
3. The method according to claim 1 or 2, wherein ZnO and Al in the aluminum-doped zinc oxide in the step (2)2O3The mass ratio of (10-99) to (1);
preferably, the mass ratio of the primary sintered material to the aluminum-doped zinc oxide is 1 (0.002-0.05).
4. The method of any one of claims 1-3, wherein said mixing of step (2) comprises dry and/or wet mixing;
preferably, the stirring frequency of the dry mixing is 20-100 Hz;
preferably, the dry mixing time is 5-120 min;
preferably, the wet-mixed solvent comprises ethanol;
preferably, the wet mixing is stirred until the solvent is completely volatilized.
5. The method according to any one of claims 1 to 4, wherein the temperature of the secondary sintering in the step (3) is 100 to 800 ℃;
preferably, the time for the secondary sintering in the step (3) is 0.5-10 h;
preferably, the oxygen concentration of the secondary sintering in the step (3) is 0-99.9 vol%.
6. The method of any one of claims 1 to 5, comprising the steps of:
(1) taking a hydroxide precursor of nickel, cobalt and manganese, and sintering for 0.5-9 h under the conditions that the temperature is 300-1000 ℃ and the oxygen concentration is 50-99.9 vol% to obtain a primary sintered material;
(2) mixing the calcined material obtained in the step (1) with nano-scale aluminum-doped zinc oxide to obtain a mixture;
(3) and (3) sintering the mixture obtained in the step (2) for 0.5-10 h at the temperature of 100-800 ℃ and under the oxygen concentration of 0-99.9 vol% to obtain the cathode material.
7. A positive electrode material, characterized in that it is produced by the production method according to any one of claims 1 to 6.
8. The positive electrode material according to claim 7, wherein the positive electrode material comprises a ternary positive electrode material and an aluminum-doped zinc oxide coating layer coated on the surface of the ternary positive electrode material.
9. A positive electrode sheet, characterized in that it comprises the positive electrode material according to claim 8.
10. A lithium ion battery comprising the positive electrode sheet of claim 9.
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Cited By (1)

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CN114388794A (en) * 2021-11-22 2022-04-22 北京化工大学 Sodium ion battery aluminum-doped zinc oxide-coated sodium nickel manganese oxide positive electrode material and preparation method thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114388794A (en) * 2021-11-22 2022-04-22 北京化工大学 Sodium ion battery aluminum-doped zinc oxide-coated sodium nickel manganese oxide positive electrode material and preparation method thereof
CN114388794B (en) * 2021-11-22 2024-04-02 北京化工大学 Aluminum-doped zinc oxide coated sodium nickel manganese oxide positive electrode material of sodium ion battery and preparation method of aluminum-doped zinc oxide coated sodium nickel manganese oxide positive electrode material

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