CN116314753A - High-voltage lithium cobaltate positive electrode active material, and preparation method and application thereof - Google Patents
High-voltage lithium cobaltate positive electrode active material, and preparation method and application thereof Download PDFInfo
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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
- H01M4/48—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
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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
- 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
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
-
- 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 discloses a high-voltage lithium cobaltate positive electrode active material, a preparation method and application thereof, wherein the preparation method selects the existing LiCoO 2 PVP as a precursor and surfactant are added into absolute ethyl alcohol and mixed uniformly; the phytic acid is taken as a doping agent to provide phosphorus element, and is dissolved in absolute ethyl alcohol; then the ethanol solution dissolved with phytic acid is slowly dripped into LiCoO 2 PVP/ethanol mixed solution. After being uniformly mixed, the solid powder obtained by centrifugation/washing/drying is presintered in argon atmosphere, and then sintered at high temperature in air atmosphere, and finally the P doped modified LiCoO is obtained 2 And a positive electrode material. The preparation method provided by the invention is green and safe, is suitable for large-scale industrial production, and is doped with P-doped LiCoO 2 The positive electrode material is under 4.5V high voltageThe circulation stability is obviously improved.
Description
Technical Field
The invention relates to the technical field of high-performance positive electrode materials of lithium ion batteries, in particular to a high-voltage lithium cobaltate positive electrode active material, and a preparation method and application thereof.
Background
With the continuous and rapid development of the fields of portable electronic equipment, electric automobiles and the like, the human society puts forward more stringent requirements on the lithium ion battery system widely applied at present, and the influence of the positive electrode active material on the performance of the lithium ion battery is dominant. Therefore, research and development of the high-performance lithium ion battery anode material with the characteristics of high specific capacity, high energy density, long-cycle stability and the like have very important significance for promoting social development.
LiCoO 2 The lithium cobalt oxide is a lithium ion battery anode material which is produced commercially and used on a large scale earlier, has the advantages of wide working voltage range, large theoretical specific capacity, large energy density, mature process and the like, and is widely used. However, the actual specific capacity of the lithium cobaltate is only about 140mAh/g and is only 50% of the theoretical specific capacity (274 mAh/g), and the LiCoO can be obviously improved by increasing the working voltage 2 But under high voltage condition>4.5V) will "de-intercalate" excess lithium ions, "causing LiCoO 2 The crystal structure of (a) is changed from a hexagonal system to a monoclinic system having no electrochemical properties, and at the same time, the asymmetric lattice of the material contracts and expands, seriously damaging the structural stability, resulting in a drastic deterioration of its cycle performance and coulombic efficiency at high voltages.
Disclosure of Invention
The invention provides a high-voltage lithium cobaltate positive electrode active material, a preparation method and application thereof, which are used for overcoming the defects of poor cycle performance and coulombic efficiency under high voltage in the prior art.
In order to achieve the above object, the present invention provides a method for preparing a high voltage type lithium cobalt oxide positive electrode active material, comprising the steps of:
s1: liCoO is added with 2 Adding PVP into absolute ethyl alcohol, and stirring until the PVP is completely dissolved;
s2: dissolving phytic acid in absolute ethyl alcohol, and stirring until the phytic acid is completely dissolved;
s3: dripping ethanol solution dissolved with phytic acid into LiCoO obtained in step S1 2 Stirring and mixing uniformly in PVP/ethanol mixed solution;
s4: centrifuging and drying the mixed solution obtained in the step S3, presintering in an inert atmosphere, and sintering in an air atmosphere to obtain the phosphorus doped modified LiCoO 2 Positive electrode active material.
In order to achieve the above purpose, the invention also provides a high-voltage lithium cobaltate positive electrode active material prepared by the preparation method; the positive electrode active material is phosphorus doped LiCoO 2 The positive electrode material consists of phosphorus doped lithium cobaltate particles.
In order to achieve the above purpose, the invention also provides an application of the high-voltage type lithium cobalt oxide positive electrode active material, and the positive electrode active material prepared by the preparation method or the positive electrode active material is applied to a lithium ion battery.
Compared with the prior art, the invention has the beneficial effects that:
1. the high-voltage lithium cobaltate positive electrode active material provided by the invention has the advantages that a small amount of P element is uniformly doped on the surface of the high-voltage lithium cobaltate positive electrode active material, so that the structural strength and the structural stability in the circulating process are improved. LiCoO which has been commercially produced at present 2 The specific capacity of the material is only about 50% of the theoretical capacity, and when the charge cut-off voltage is increased to obtain higher capacity, the structure of the material can be subjected to serious irreversible change, the cycle performance is rapidly deteriorated, and the application range of the material is greatly limited. The main reason is LiCoO under high voltage working conditions 2 The O element in (c) will be detached from the crystal lattice, resulting in collapse of its layered structure. Aiming at the defects of the prior art, the surface crystal lattice of the positive electrode active material modified lithium cobaltate prepared by the preparation method provided by the invention is uniformly doped with P element, the P part occupies the position of Co element and forms stronger ionic bonding effect with O element, the O element in the lithium cobaltate material is prevented from being separated in the circulation process, and the P element has the effect of supporting the lamellar structure, thereby stabilizing LiCoO 2 Is a structure of (a). Therefore, the positive electrode active material prepared by the preparation method provided by the invention can obviously improve the high-electricity performanceCycle performance under pressure and coulombic efficiency.
2. The existing phosphorus doping process generally utilizes phosphate such as sodium hypophosphite and the like to decompose at high temperature to generate phosphine, and the phosphine is used as a phosphorus source for doping treatment, so that the phosphine has severe toxicity, potential safety hazard exists in the preparation process, and the large-scale preparation is not facilitated. The preparation method of the high-voltage lithium cobaltate positive electrode active material provided by the invention comprises the steps of firstly selecting absolute ethyl alcohol as a solvent, and carrying out commercial mass production on LiCoO 2 PVP (polyvinylpyrrolidone) as a surfactant as a modified matrix; phytic acid (C) 6 H 18 O 24 P 6 ) Providing a P source as a dopant, and dissolving the P source in absolute ethyl alcohol to obtain a solution; then the ethanol solution of phytic acid is slowly dropped into LiCoO 2 Uniformly mixing in the PVP/ethanol mixed solution. PVP has high surface activity during mixing, and can effectively improve LiCoO 2 Surface state of (C) such that LiCoO 2 The surface can uniformly adsorb phytic acid; in addition, adsorption on LiCoO can be ensured through two sintering processes of argon atmosphere pre-sintering and air atmosphere sintering 2 The surface phytic acid dopes the P element into the surface lattice of the lithium cobaltate to obtain LiCoO with stable structure and excellent cycle performance under high voltage 2 Positive electrode active material. The preparation method provided by the invention is environment-friendly and suitable for large-scale commercial production, and the prepared positive electrode material has excellent structural stability, long-cycle stability under high voltage and high coulombic efficiency. The positive electrode material is used in a lithium ion battery, so that the lithium ion battery has high practical specific capacity and energy density, excellent long-cycle performance under high voltage and excellent coulombic efficiency.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.
FIG. 1 is an XRD spectrum of doped P-LCO and commercial-LCO prepared in example 1;
FIG. 2 is a {111} crystal plane spectrum of the doped P-LCO and commercial-LCO prepared in example 1;
FIG. 3 is an SEM image at 500nm of doped P-LCO prepared according to example 1;
FIG. 4 is a TEM image of the doped P-LCO of example 1 at 2 μm;
FIG. 5 is a HRTEM image of the doped P-LCO of example 1 at 5 nm;
FIG. 6 is an EDS picture of the P-LCO doped fabricated in example 1;
FIG. 7 is a graph showing the distribution of P-LCO doped elements obtained in example 1;
FIG. 8 is a graph showing the cycle performance of a lithium ion battery doped with P-LCO as a positive electrode prepared in example 1;
fig. 9 is a graph of median voltage of a lithium ion battery doped with P-LCO as a positive electrode prepared in example 1.
The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In addition, the technical solutions of the embodiments of the present invention may be combined with each other, but it is necessary to be based on the fact that those skilled in the art can implement the technical solutions, and when the technical solutions are contradictory or cannot be implemented, the combination of the technical solutions should be considered as not existing, and not falling within the scope of protection claimed by the present invention.
The drugs/reagents used are all commercially available without specific description.
The invention provides a preparation method of a high-voltage lithium cobaltate positive electrode active material, which comprises the following steps:
s1: liCoO is added with 2 And PVP is added into absolute ethyl alcohol and stirred until the PVP is completely dissolved.
S2: dissolving phytic acid in absolute ethanol, and stirring until the phytic acid is completely dissolved.
S3: dripping ethanol solution dissolved with phytic acid into LiCoO obtained in step S1 2 And (3) in the PVP/ethanol mixed solution, stirring and mixing uniformly.
S4: centrifuging and drying the mixed solution obtained in the step S3, presintering in an inert atmosphere, and sintering in an air atmosphere to obtain the phosphorus doped modified LiCoO 2 Positive electrode active material.
Centrifuging, removing supernatant, and oven drying.
Lithium cobaltate is one of the most mature positive electrode materials in the current commercial lithium ion battery, but the actual specific capacity is only 140mAh g -1 About, only the theoretical capacity (274 mAh g -1 ) About 50%. By increasing the operating voltage of the battery, liCoO can be greatly increased 2 The specific capacity and energy density of the positive electrode material, but the traditional lithium cobalt oxide positive electrode material cannot directly work above 4.5V, and the charging under the high-voltage condition can cause excessive lithium ions to be 'deintercalated' and accompanied by oxygen elements to be continuously deintercalated from a crystal lattice, so that the structure of the positive electrode material is irreversibly transformed, and the discharge capacity and the cycle performance of the material are rapidly deteriorated. In view of the above problems, the present invention is creatively directed to a method for producing a polypeptide with phytic acid (C 6 H 18 O 24 P 6 ) As a phosphorus source, phosphorus doped lithium cobaltate is prepared to improve its cycle performance at high voltages.
Preferably, in step S1, the LiCoO 2 The mass ratio of the PVP to the PVP is 1:1.5-2.5; the volume of the absolute ethyl alcohol is 200-300 mL. When the mass ratio of lithium cobaltate to PVP is optimal at 1:2, too little PVP can lead to LiCoO 2 Insufficient surface improvement, and inability to uniformly adsorb dopants; the excessive PVP not only causes waste, but also reduces the activity of the PVP, and the wetting and dispersing effects on the surface of the lithium cobaltate are poor; the appropriate amount of PVP is beneficial to LiCoO 2 Surface is uniformly suckedAnd the doping agent is added, so that the uniform doping in the subsequent step is facilitated.
Preferably, in step S1, the temperature of the stirring is room temperature (25 ℃ C.) for 0.5 to 1 hour. The stirring time is preferably 1h, which is favorable for LiCoO 2 Full contact with PVP.
Preferably, in step S2, the volume fraction of phytic acid in the ethanol solution in which phytic acid is dissolved is 2 to 3%. Considering the amount of lithium cobaltate, the volume fraction of the phytic acid is preferably 2.5%, because the phytic acid is used as a dopant to provide a P source, too little phytic acid can lead to less doping element in the subsequent doping process, and the improvement of the cycle performance of the lithium cobaltate under high voltage is not obvious; excessive phytic acid can cause more doping elements in the subsequent doping process, thereby causing larger distortion of the crystal structure of the lithium cobaltate and being unfavorable for the stability of the structure; therefore, the proper amount of phytic acid can lead the doped element amount to be moderate in the subsequent doping process without changing LiCoO 2 And the structural stability and the cycling stability under high voltage of the cathode material are improved while the crystal structure of the cathode material is improved.
Preferably, in step S2, the temperature of the stirring is room temperature (25 ℃ C.) for 0.5 to 1 hour. The stirring time is preferably 1h, which is favorable for completely dissolving the phytic acid in the ethanol.
Preferably, in the step S3, the dropping speed is 3-5 mL/min; the temperature of stirring is 60 ℃ and the time is 0.5-1 h. The dripping rate is preferably 3mL/min, the stirring time is preferably 1h, and LiCoO can be ensured 2 Is fully contacted with the phytic acid and enables the surface of the phytic acid to be uniformly adsorbed.
Preferably, in the step S4, the rotation speed of the centrifugation is 7500r/min, the time is 3-5 min, and the centrifugation times are 1-3 times; the temperature of the drying is 60-80 ℃ and the time is 4-5 h. The centrifugation times are preferably 3 times, and residual PVP and non-adsorbed phytic acid are sufficiently cleaned; the drying time is preferably 1h, so that no residual ethanol is ensured.
Preferably, in step S4, the pre-sintering process specifically includes:
heating the sintering temperature from room temperature to 650 ℃ in argon atmosphere at a heating rate of 2 ℃/min, and preserving heat for 2h;
the sintering process comprises the following steps:
in the air atmosphere, the sintering temperature is raised to 750 ℃ from room temperature at a heating rate of 5 ℃/min, and the temperature is kept for 5 hours.
Argon atmosphere presintering is firstly carried out, and then air atmosphere sintering is carried out, so that the P element is beneficial to LiCoO 2 The lattice is uniformly and sufficiently doped.
The invention also provides a high-voltage lithium cobaltate positive electrode active material prepared by the preparation method; the positive electrode active material is phosphorus doped LiCoO 2 The positive electrode material consists of phosphorus doped lithium cobaltate particles.
The invention also provides application of the high-voltage lithium cobaltate positive electrode active material, and the positive electrode active material prepared by the preparation method or the positive electrode active material is applied to a lithium ion battery.
Example 1
The embodiment provides a preparation method of a high-voltage lithium cobaltate positive electrode active material, which comprises the following steps:
s1 1.5g commercial LiCoO 2 And 3g of surfactant PVP dispersed in 250mL of absolute ethyl alcohol, and stirred for 30min at normal temperature (25 ℃);
s2, adding 1mL of phytic acid into 40mL of ethanol (volume fraction is 2.5%), and stirring for 30min at normal temperature (25 ℃);
s3, dripping the ethanol solution of the phytic acid obtained in the step S2 to LiCoO obtained in the step S1 at a rate of 3mL/min 2 PVP/ethanol mixed solution, and stirring at 60 ℃ for 1h;
s4, washing the mixed solution obtained in the step S3 with absolute ethyl alcohol and centrifuging for 3 times at a centrifuging speed of 7500r/min and a centrifuging time of 3min each time to obtain the preliminary modified LiCoO 2 And (3) powder. The mixture was placed in a forced air drying oven, dried by forced air at 60℃for 1 hour, and evaporated to dryness. Placing the sample obtained by evaporation in a ceramic crucible and placing in a tube furnace, continuously introducing high-purity Ar gas, heating to 650 ℃ at a speed of 2 ℃/min under the Ar gas atmosphere, and preserving heat for 2 hours; then the mixture is placed in a muffle furnace after being naturally cooled, and the mixture is placed under the air atmosphere at the speed of 5 ℃/minAnd raising the temperature to 750 ℃ and preserving the temperature for 5 hours, and then naturally cooling the mixture to obtain the high-voltage lithium cobaltate positive electrode active material.
FIG. 1 shows XRD spectra of a high voltage type lithium cobalt oxide positive electrode active material and a commercial lithium cobalt oxide obtained in this example, and as can be seen from FIG. 1, the positive electrode material prepared has an alpha-NaFeO 2 The layered structure, the crystal structure is consistent with commercial lithium cobaltate, and the original structure is not destroyed by doping treatment.
Fig. 2 is a graph showing the comparison of the peak positions of the high-voltage lithium cobaltate positive electrode active material and the crystal face XRD of the commercial lithium cobaltate {111} crystal face, which shows that the peak positions are obviously shifted leftwards after doping treatment, and the P replaces part of Co point positions, and forms stronger ionic bonding action with O element so as to make the unit cell smaller.
Fig. 3 and 4 are SEM and TEM images of the high voltage type lithium cobaltate cathode active material prepared in this example, respectively, and it can be seen that the particle size of the lithium cobaltate particles is about 4-5 μm, and is composed of several lithium cobaltate nanoparticles.
Fig. 5 is a high-resolution TEM image of the high-voltage type lithium cobalt oxide positive electrode active material prepared in this example, and it can be seen that the exposed crystal plane is {111} crystal plane.
Fig. 6 and fig. 7 are respectively an EDS element energy spectrum diagram and an element distribution diagram of the high-voltage type lithium cobalt oxide positive electrode active material prepared in this example, and it can be seen that the high-voltage type lithium cobalt oxide prepared through doping treatment contains Co, O and P elements, and the Co, O and P elements are uniformly distributed in the P-doped lithium cobalt oxide material.
The high-voltage type lithium cobalt oxide positive electrode active material (P-LCO) and the commercialized-LCO prepared in the embodiment are used as the positive electrode of a lithium ion battery, and the charge-discharge cycle performance test is carried out in a voltage interval of 4.5V-3V; as can be seen from the cycle performance curves shown in FIG. 8, the initial discharge capacity is 192mAh/g under the charge-discharge current density of P-LCO and 1C, and after 155 charge-discharge cycles, the discharge capacity is kept at 162mAh/g, the capacity retention rate is 84%, and the average coulomb efficiency is 99.5%. The P-doped lithium cobaltate is disclosed as a positive electrode of a high-voltage lithium ion battery, and has excellent cycle performance and high reversibility. Under the same test condition, the first discharge capacity of the commercial LCO is 176mAh/g, the discharge capacity of the commercial LCO is reduced to 120mAh/g after 155 charge-discharge cycles, the capacity retention rate is only 68%, and the average coulombic efficiency is only 94.7%, which indicates that the commercial LCO has poor cycle performance and low reversibility under high voltage.
In addition, fig. 9 compares the median discharge voltages of P-LCO and commercial-LCO during cycling, it is evident that P-doped LCO can maintain the discharge voltage relatively smoothly at high voltages, while commercial LCO discharge voltage decays rapidly at high voltages. Further explaining the key effect of P doping on the comprehensive electrochemical performance of the lithium ion battery.
Example 2
The present embodiment provides a method for preparing a high voltage type lithium cobalt oxide positive electrode active material, and compared with the embodiment 1, the volume fraction of the phytic acid in the step S2 in the embodiment is 2%, so as to obtain the high voltage type lithium cobalt oxide positive electrode active material. The other steps are the same as in example 1.
The content of the P element on the surface of the high-voltage type lithium cobalt oxide positive electrode active material prepared in the embodiment has smaller difference than that in the embodiment 1, and the cycle performance under high voltage (about 4.5V) is still obviously improved compared with that of common lithium cobalt oxide.
Example 3
The present embodiment provides a method for preparing a high voltage type lithium cobalt oxide positive electrode active material, and compared with the embodiment 1, the volume fraction of the phytic acid in the step S2 in the embodiment is 3%, so as to obtain the high voltage type lithium cobalt oxide positive electrode active material. The other steps are the same as in example 1.
The content of the P element on the surface of the high-voltage type lithium cobalt oxide positive electrode active material prepared in the embodiment has smaller difference than that in the embodiment 1, and the cycle performance under high voltage (about 4.5V) is still obviously improved compared with that of common lithium cobalt oxide.
The foregoing description is only of the preferred embodiments of the present invention and is not intended to limit the scope of the invention, and all equivalent structural changes made by the description of the present invention and the accompanying drawings or direct/indirect application in other related technical fields are included in the scope of the invention.
Claims (10)
1. The preparation method of the high-voltage lithium cobaltate positive electrode active material is characterized by comprising the following steps of:
s1: liCoO is added with 2 Adding PVP into absolute ethyl alcohol, and stirring until the PVP is completely dissolved;
s2: dissolving phytic acid in absolute ethyl alcohol, and stirring until the phytic acid is completely dissolved;
s3: dripping ethanol solution dissolved with phytic acid into LiCoO obtained in step S1 2 Stirring and mixing uniformly in PVP/ethanol mixed solution;
s4: centrifuging and drying the mixed solution obtained in the step S3, presintering in an inert atmosphere, and sintering in an air atmosphere to obtain the phosphorus doped modified LiCoO 2 Positive electrode active material.
2. The preparation method according to claim 1, wherein in step S1, the LiCoO 2 The mass ratio of the PVP to the PVP is 1:1.5-2.5; the volume of the absolute ethyl alcohol is 200-300 mL.
3. The preparation method according to claim 1 or 2, wherein in step S1, the stirring temperature is room temperature for 0.5 to 1 hour.
4. The method according to claim 1, wherein in the step S2, the volume fraction of the phytic acid in the ethanol solution in which the phytic acid is dissolved is 2 to 3%.
5. The method according to claim 1, wherein in step S2, the stirring temperature is room temperature for 0.5 to 1 hour.
6. The method according to claim 1, wherein in step S3, the dropping rate is 3 to 5mL/min; the temperature of stirring is 60 ℃ and the time is 0.5-1 h.
7. The preparation method according to claim 1, wherein in the step S4, the rotational speed of the centrifugation is 7500r/min, the time is 3 to 5min, and the number of times of centrifugation is 1 to 3 times; the temperature of the drying is 60-80 ℃ and the time is 4-5 h.
8. The method according to claim 1, wherein in step S4, the pre-sintering process is specifically:
heating the sintering temperature from room temperature to 650 ℃ in argon atmosphere at a heating rate of 2 ℃/min, and preserving heat for 2h;
the sintering process comprises the following steps:
in the air atmosphere, the sintering temperature is raised to 750 ℃ from room temperature at a heating rate of 5 ℃/min, and the temperature is kept for 5 hours.
9. A high voltage type lithium cobaltate positive electrode active material characterized by being prepared by the preparation method according to any one of claims 1 to 8; the positive electrode active material is phosphorus doped LiCoO 2 The positive electrode material consists of phosphorus doped lithium cobaltate particles.
10. The application of the high-voltage type lithium cobalt oxide positive electrode active material is characterized in that the positive electrode active material prepared by the preparation method of any one of claims 1 to 8 or the positive electrode active material of claim 9 is applied to a lithium ion battery.
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