CN112928251B - Lithium cobaltate composite material and preparation method thereof - Google Patents

Lithium cobaltate composite material and preparation method thereof Download PDF

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CN112928251B
CN112928251B CN202110087455.1A CN202110087455A CN112928251B CN 112928251 B CN112928251 B CN 112928251B CN 202110087455 A CN202110087455 A CN 202110087455A CN 112928251 B CN112928251 B CN 112928251B
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lithium
phosphate
cobalt
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composite material
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CN112928251A (en
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曾家江
于丽秋
李素丽
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Zhuhai Cosmx Battery 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
    • H01M4/364—Composites as mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—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
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • 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 lithium cobaltate composite material and a preparation method thereof, wherein the lithium cobaltate composite material comprises the following components in parts by weight: a substrate comprising lithium cobaltate; and the coating layer comprises lithium-deficient cobalt lithium phosphate and is coated on the surface of the substrate. The invention synthesizes the lithium cobaltate composite material containing the coating layer by coating the lithium phosphate without lithium in a nanometer level. The composite material is used as a positive electrode material, and compared with a base material, the capacity is not lost under the condition of improving the cycle performance and the storage performance; compared with lithium cobalt phosphate coated lithium cobalt oxide, the lithium cobalt phosphate has higher conductivity, thus the electric specific capacity is higher and the cycle performance is better; compared with lithium cobalt oxide coated by lithium cobalt phosphate, the surface is more stable, so that the high-temperature storage performance and the high-temperature cycle performance are better.

Description

Lithium cobaltate composite material and preparation method thereof
Technical Field
The invention relates to the technical field of batteries, in particular to a lithium cobaltate composite material and a preparation method thereof.
Background
At present, the research hot spots of 3C consumer lithium batteries mainly focus on two aspects of high energy density and high rate, and particularly, the high energy density is highly related to the performance of the positive electrode material. In order to increase the energy density, the charge cut-off voltage is continuously increased in use of the battery. However, under the condition that the battery has higher volume/mass energy density, the high-delithiation state cathode material can show stronger oxidizability, and phenomena such as irreversible phase change, oxygen precipitation, transition metal dissolution and cracks are more easily generated, so that the material fails.
The material improvement method can effectively improve the dissolution of transition metal and improve the cycle performance and high-temperature storage performance of the material by coating proper substances.
The electrode material in the existing coating mode has relatively poor stability and poor conductivity, and can reduce capacity and cycle.
Disclosure of Invention
In view of the above, the invention provides a lithium cobaltate composite material and a preparation method thereof, which are used for solving the problems of poor stability, poor conductivity and the like in the existing coating material.
In order to solve the technical problems, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a lithium cobaltate composite material comprising:
a substrate comprising lithium cobaltate;
and the coating layer comprises lithium-deficient cobalt lithium phosphate and is coated on the surface of the substrate.
Further, the composite material further comprises:
a transition layer comprising lithium cobaltate in a lithium deficient state intermediate the substrate and the cladding layer.
Further, the thickness of the coating layer is 0.1-5 nm, and/or
The thickness of the transition layer is 0.1-10 nm.
Further, the chemical formula of the lithium-deficient state lithium cobalt phosphate is Lix1CoPO4Wherein 0.3<x1<0.7, and/or
The chemical formula of the lithium-deficient lithium cobaltate is Liy1CoO2Wherein, 0.3<y1<0.9。
Further, the clad layer includes:
the first lithium cobalt phosphate layer is coated on the surface of the transition layer or the substrate, and the chemical formula of lithium-deficient lithium cobalt phosphate in the first lithium cobalt phosphate layer is Lix2CoPO4Wherein 0.3<x2<0.7；
The second lithium cobalt phosphate layer is coated on the surface of the first lithium cobalt phosphate layer, the first lithium cobalt phosphate layer is lithium-deficient lithium cobalt phosphate, and the chemical formula of the lithium-deficient lithium cobalt phosphate in the second lithium cobalt phosphate layer is Lix3CoPO4Wherein 0.3<x3<0.7, and x3<x2。
Further, the particle size of the lithium cobaltate composite material is 12-18 mu m.
In a second aspect, the present invention provides a preparation method of a lithium cobaltate composite material, the preparation method comprising:
providing nanoscale lithium-deficient cobalt lithium phosphate LixCoPO4，0.3<x<0.7；
Mixing the nanoscale lithium-deficient cobalt lithium phosphate with lithium cobaltate, wherein the mass of the lithium-deficient cobalt lithium phosphate is 0.02-2% of that of the lithium cobaltate, and performing heat treatment after mixing to obtain the lithium cobaltate composite material.
Further, the nanoscale lithium-deficient state lithium cobalt phosphate LixCoPO4(0.3<x<0.7) is in the range of 5nm to 200 nm.
Further, the temperature of the heat treatment is 700-1000 ℃, and the time of the heat treatment is 5-15 h.
In a third aspect, the present invention provides a positive electrode material, including the above lithium cobaltate composite material.
In a fourth aspect, the invention provides a battery comprising the positive electrode material.
The technical scheme of the invention has the following beneficial effects:
the invention provides a lithium cobaltate composite material and a preparation method thereof, wherein the lithium cobaltate composite material comprises the following components in parts by weight: a substrate comprising lithium cobaltate; and the coating layer comprises lithium-deficient cobalt lithium phosphate and is coated on the surface of the substrate.
The invention synthesizes the lithium cobaltate composite material containing the coating layer with the double-layer film structure by coating the lithium phosphate without lithium in a nanometer level. The composite material is used as a positive electrode material, and compared with a base material, the capacity is not lost under the condition of improving the cycle performance and the storage performance; compared with lithium cobalt phosphate coated lithium cobalt oxide, the lithium cobalt phosphate has higher conductivity, thus the electric specific capacity is higher and the cycle performance is better; compared with lithium cobalt oxide coated by lithium cobalt phosphate, the surface is more stable, so that the high-temperature storage performance and the high-temperature cycle performance are better.
Drawings
FIG. 1 is a schematic diagram of a material mixture and a sintered product;
FIG. 2 is a diagram of the morphology of matrix lithium cobaltate, lithium cobalt phosphate in a lithium deficient state, a blend and a lithium cobaltate composite;
FIG. 3 is a graph of the full electric high temperature cycle performance of the matrix lithium cobaltate, sample 1, sample 2, and sample 3;
FIG. 4 is a graph of the full electric high temperature storage performance of the matrix lithium cobaltate, sample 1, sample 2, and sample 3;
FIG. 5 is a graph of the full electric high temperature cycle performance of the matrix lithium cobaltate, sample 1, sample 2, and sample 4;
fig. 6 is a graph of the full electric high temperature storage performance of the matrix lithium cobaltate, sample 1, sample 2, and sample 4.
Detailed Description
For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention in conjunction with the following examples, but it will be understood that the description is intended to illustrate the features and advantages of the invention further, and not to limit the invention.
In a first aspect, the present invention provides a lithium cobaltate composite material comprising:
a substrate comprising lithium cobaltate;
and the coating layer comprises lithium-deficient cobalt lithium phosphate and is coated on the surface of the substrate.
That is, the composite material provided by the invention is to cover a layer of lithium-deficient lithium cobalt phosphate on the surface of the matrix lithium cobalt oxide.
According to some embodiments of the invention, the composite further comprises: a transition layer comprising lithium cobaltate in a lithium deficient state intermediate the substrate and the cladding layer.
That is, the composite material provided in the present invention is a material having a two-layer film structure, and the two layers are: the first layer is transition layer lithium cobalt oxide in lithium-deficient state, and the first layer is a layer formed by a small amount of lithium cobalt oxide in lithium-deficient state on the surface layer of a substrate after a small amount of lithium ions are lost; the second layer is a cladding layer lithium-deficient lithium-state lithium cobalt phosphate, and the layer is the lithium-deficient lithium-state lithium cobalt phosphate which is still in a lithium-deficient state after the lithium-deficient lithium cobalt phosphate reacts with the matrix lithium cobalt oxide to absorb part of lithium ions. The composite material is used as a positive electrode material, and compared with a base material, namely lithium cobaltate, under the condition of improving the cycle performance and the storage performance, the capacity is not lost; compared with lithium cobalt phosphate coated lithium cobalt oxide, the lithium cobalt phosphate has higher conductivity, thus the electric specific capacity is higher and the cycle performance is better; compared with lithium cobalt phosphate coated lithium cobalt oxide, the surface is more stable, so that the high-temperature storage performance and the high-temperature cycle performance are better.
According to some embodiments of the invention, the coating layer has a thickness of 0.1 to 5nm, and/or the transition layer has a thickness of 0.1 to 10 nm.
According to some embodiments of the invention, the lithium-deficient lithium cobalt phosphate has the formula Lix1CoPO4Wherein 0.3<x1<0.7, and/or the lithium cobaltate in lithium-deficient state has the formula Liy1CoO2, wherein, 0.3<y1<0.9。
According to some embodiments of the invention, the cladding layer comprises:
the first lithium cobalt phosphate layer is coated on the surface of the transition layer or the substrate, and the chemical formula of lithium-deficient lithium cobalt phosphate in the first lithium cobalt phosphate layer is Lix2CoPO4Wherein 0.3<x2<0.7；
The second lithium cobalt phosphate layer is coated on the surface of the first lithium cobalt phosphate layer, the first lithium cobalt phosphate layer is lithium-deficient lithium cobalt phosphate, and the chemical formula of the lithium-deficient lithium cobalt phosphate in the second lithium cobalt phosphate layer is Lix3CoPO4Wherein 0.3<x3<0.7, and x3<x2。
According to some embodiments of the invention, the lithium cobaltate composite material has a particle size of 12 to 18 μm.
In a second aspect, the present invention provides a preparation method of a lithium cobaltate composite material, the preparation method comprising:
providing nanoscale lithium-deficient cobalt lithium phosphate LixCoPO4，0.3<x<0.7；
Mixing the nanoscale lithium-deficient cobalt lithium phosphate with lithium cobaltate, wherein the mass of the lithium-deficient cobalt lithium phosphate is 0.02-0.2% of that of the lithium cobaltate, and performing heat treatment after mixing to obtain the lithium cobaltate composite material.
That is, the present invention uses lithium cobaltate and lithium cobalt phosphate Li in a lithium deficient statexCoPO4(0.3<x<0.7) as a raw material, adding lithium-deficient cobalt lithium phosphate according to a certain mass ratio, and sintering to obtain the lithium cobalt oxide composite material. Fig. 1 is a schematic diagram of a material mixture and a sintered product, and it can be seen from fig. 1 that during the sintering process, lithium-deficient lithium cobalt phosphate absorbs a small amount of lithium ions on the surface of the matrix lithium cobalt oxide, and a thin lithium-deficient lithium cobalt oxide transition layer (i.e., the transition layer in the diagram) is formed on the surface of the matrix after the matrix lithium cobalt oxide loses a small amount of lithium ions. Meanwhile, after absorbing a small amount of lithium ions, the lithium-deficient cobalt lithium phosphate still maintains a lithium-deficient state, and becomes a lithium-deficient cobalt lithium phosphate coating layer (i.e., a coating layer in the figure) on the outermost layer of the lithium cobalt oxide composite material.
According to other embodiments of the present invention, the nanoscale lithium-deficient lithium cobalt lithium phosphate LixCoPO4(0.3<x<0.7) is in the range of 5nm to 200 nm. The nanoscale lithium-deficient cobalt lithium phosphate LixCoPO4(0.3<x<0.7) crushing the material to a nano-state by a sand mill, so that lithium cobalt lithium phosphate Li in a lithium state is obtainedxCoPO4(0.3<x<0.7) is crushed to nanometer level, mainly to ensure that the cladding of lithium-deficient lithium cobalt phosphate is more uniform.
According to other embodiments of the present invention, the nanoscale lithium-deficient lithium cobalt lithium phosphate LixCoPO4(0.3<x<0.7) the preparation method comprises the following steps:
(1) preparing 0.15-1.7mol/L cobalt nitrate salt mixed solution of 0.1-0.5mol/L lithium nitrate, wherein the amount of cobalt nitrate is 1.5-3 times of that of the lithium nitrate, and adjusting the pH value to 4.5-5.5 to obtain solution A for later use;
(2) preparing a mixed solution of 0.1-0.5mol/L phosphoric acid and 0.1-0.5mol/L sodium N-acyl sarcosinate, wherein the amount of the phosphoric acid is 1.5-3 times of that of the sodium N-acyl sarcosinate to obtain a solution B;
(3) the solution A and the solution B are mixed in equal volume and are treated by a hydrothermal method, wherein the hydrothermal treatment temperature is 100 ℃ and 150 ℃, and the hydrothermal treatment time is 6-8 h; cleaning and drying to obtain a solid material;
(4) sintering the obtained solid material at the sintering temperature of 500-700 ℃ for 3-6 h; thus obtaining lithium-deficient state lithium cobalt phosphate;
(5) crushing the material by using a sand mill to obtain nano-grade lithium-deficient cobalt lithium phosphate LixCoPO4(0.3<x<0.7)。
According to other embodiments of the present invention, the temperature of the heat treatment is 700-. In the invention, the heat treatment condition is controlled to ensure that the coating is successful on one hand, and on the other hand, the lithium-deficient cobalt lithium phosphate can be infiltrated to a certain degree in the sintering process, and the heat treatment condition is controlled to ensure that the infiltration amount of the lithium-deficient cobalt lithium phosphate is less.
In a third aspect, the invention provides a positive electrode material, wherein the positive electrode material comprises the lithium cobaltate composite material. Compared with a base material, namely lithium cobaltate, the positive electrode material has no loss of capacity under the condition of improving the cycle performance and the storage performance; compared with a positive electrode material of lithium cobalt oxide coated with lithium cobalt phosphate, the lithium cobalt oxide positive electrode material has higher conductivity, higher specific capacity and better cycle performance; compared with a positive electrode material of lithium cobalt oxide coated by lithium cobalt phosphate, the surface is more stable, so that the high-temperature storage performance and the high-temperature cycle performance are better.
In a fourth aspect, the invention provides a battery comprising the positive electrode material. Compared with the existing cobalt acid lithium battery, the battery provided by the invention has the advantages of no loss of capacity, higher specific capacity, improved high-temperature cycle performance and improved high-temperature storage performance.
The invention is further illustrated by the following specific examples.
Comparative example 1
Taking 500g of matrix lithium cobaltate, taking 0.2g of nano cobalt phosphate, uniformly mixing, carrying out heat treatment at 850 ℃, keeping the temperature for 6 hours, and cooling along with a furnace. Thus, a composite sample of cobalt phosphate coated lithium cobaltate was obtained and recorded as sample 1.
Comparative example 2
Taking 500g of matrix lithium cobaltate, taking 0.2g of nano lithium cobalt phosphate, uniformly mixing, carrying out heat treatment at 850 ℃, keeping the temperature for 6 hours, and cooling along with a furnace. Thus, a composite sample of lithium cobalt phosphate-coated lithium cobalt oxide was obtained and recorded as sample 2.
Example 1
The first step is as follows: preparation of lithium-deficient lithium cobalt phosphate
Dissolving 0.1mol of lithium nitrate and 0.3mol of cobalt nitrate in 1L of deionized water, adjusting the pH value to 5.5, adding 0.3mol of phosphoric acid and 0.1mol of N-acyl sarcosine sodium, carrying out hydrothermal reaction for 6h at 100 ℃, cooling and drying after the reaction is finished, thus obtaining a solid precursor; presintering the precursor for 2h at 180 ℃ in a nitrogen environment, heating to 700 ℃ at the speed of 5 ℃/min, and sintering at constant temperature for 3h to obtain lithium-deficient lithium cobalt phosphate Li0.33CoPO4. Lithium-deficient lithium cobalt lithium phosphate (Li) is ground by a sand mill0.33CoPO4Crushing to obtain nanometer level lithium-deficient lithium cobalt lithium phosphate Li0.33CoPO4。
The second step is that: preparation of lithium cobaltate composite material
Taking 500g of matrix lithium cobaltate, taking 0.2g of crushed lithium-deficient lithium cobalt phosphate Li0.33CoPO4Mixing uniformly, carrying out heat treatment at 850 ℃, keeping the temperature for 6 hours, and cooling along with the furnace. Thus obtaining a lithium-deficient lithium cobalt phosphate-coated lithium cobalt oxide composite sample, which is recorded as sample 3.
FIG. 2 is a diagram showing the morphology of the matrix lithium cobaltate, lithium-deficient lithium cobalt phosphate, the blend and the lithium cobaltate composite material in this example. The first graph is a lithium cobaltate matrix, the second graph is lithium-deficient cobalt lithium phosphate, the third graph is the appearance of a mixture, the mixture is a mixture of the lithium cobaltate matrix and the lithium-deficient cobalt lithium phosphate, the mixture is uniformly mixed as can be seen from the graph in FIG. 3, and the fourth graph is a product after heat treatment, and the lithium cobaltate matrix and the lithium-deficient cobalt lithium phosphate are fused after heat treatment.
And respectively preparing the batteries by using the matrix lithium cobaltate, the sample 1, the sample 2 and the sample 3 as anode materials.
The first discharge capacity of the four batteries was tested, and the test results are shown in table 1.
The test method comprises the following steps: 4 positive electrode material samples were prepared into full cells for capacity testing. Under normal temperature, the cut-off voltage of charge and discharge is 3.0-4.45V, and the charge and discharge multiplying power is 0.2C/0.2C.
The conductivity of the four powders of matrix lithium silicate, sample 1, sample 2, and sample 3 was measured and the results are shown in table 2. The test instrument uses a powder resistance tester to perform conductivity test under the condition of 8KN of pressure.
TABLE 1 first discharge capacity RT,4.45V 0.2C specific discharge capacity (mAhg)-1)
Matrix lithium silicate Sample 1 Sample 2 Sample 3
181 181.1 179.6 181.5
TABLE 2 powder conductivity (S/cm)8KN
Matrix lithium silicate Sample 1 Sample 2 Sample 3
1.63E-05 2.63E-05 1.08E-07 2.33E-05
As can be seen from table 1, the battery prepared from the sample coated with lithium cobalt phosphate (sample 2) has the lowest specific discharge capacity, and the other samples are close to each other, which corresponds to the lowest conductivity of the sample coated with lithium cobalt phosphate (sample 2) in table 2.
Fig. 3 is a graph of the full electric high temperature cycle performance of the matrix lithium cobaltate, sample 1, sample 2, and sample 3. The test method comprises the following steps: and (4) testing the full battery, wherein the test environment temperature is 45 ℃, the charge-discharge cut-off voltage range is 3.0-4.45V, and the charge-discharge multiplying power is 1C/1C. It can be seen from fig. 3 that the high temperature cycling performance of the coated synthetic additive samples performed best.
Fig. 4 is a graph of the full electric high temperature storage performance of the matrix lithium cobaltate, sample 1, sample 2, and sample 3. The test method comprises the following steps: and (4) testing the whole battery, wherein the testing environment temperature is 85 ℃, and the testing time is 6 hours. It can be seen from fig. 4 that the storage performance coated lithium cobalt phosphate and coated lithium deficient lithium cobalt phosphate additive samples are close to and superior to the matrix and coated cobalt phosphate materials.
Example 2
The first step is as follows: preparation of lithium-deficient lithium cobalt phosphate
Dissolving 0.1mol of lithium nitrate and 0.10mol of cobalt nitrate in 1L of deionized water, adjusting the pH value to 5.0, adding 0.15mol of phosphoric acid and 0.1mol of N-acyl sodium sarcosinate, carrying out hydrothermal reaction for 8h at 120 ℃, cooling and drying after the reaction is finished, thus obtaining a solid precursor; presintering the precursor for 2h at 180 ℃ in a nitrogen environment, heating to 500 ℃ at the speed of 3 ℃/min, and sintering at constant temperature for 3h to obtain lithium-deficient lithium cobalt phosphate Li0.66CoPO4. Lithium-deficient lithium cobalt phosphate Li by using sand mill0.66CoPO4Crushing to obtain nano lithium-deficient lithium cobalt lithium phosphate Li0.66CoPO4。
The second step is that: preparation of lithium cobaltate composite material
Taking 500g of matrix lithium cobaltate, taking 0.10g of crushed lithium-deficient lithium cobalt phosphate Li0.66CoPO4Mixing uniformly, carrying out heat treatment at 950 ℃, keeping the temperature for 6 hours, and cooling along with the furnace. Thus obtaining a lithium-deficient lithium cobalt phosphate-coated lithium cobalt oxide composite sample, which is recorded as sample 4.
The lithium silicate matrix, sample 1, sample 2 and sample 4 were used as the positive electrode materials to prepare the batteries.
The first discharge capacity of the four batteries was measured in the same manner as in example 1, and the results are shown in table 3.
TABLE 3 first discharge capacity RT,4.45V 0.2C specific discharge capacity (mAhg)-1)
Matrix lithium silicate Sample No. 1 Sample 2 Sample No. 4
181 181.1 179.6 181.2
As can be seen from table 3, the battery prepared from the sample coated with lithium cobalt phosphate (sample 2) had the lowest specific discharge capacity, and the other samples were close to each other.
Fig. 5 is a graph of the full-electric high-temperature cycle performance of the matrix lithium cobaltate, the sample 1, the sample 2 and the sample 4, the testing method is the same as that of the example 1, and as can be seen from fig. 5, the coated cobalt phosphate, the coated lithium cobalt phosphate and the lithium-deficient lithium cobalt phosphate samples are superior to the blank samples, and the coated lithium-deficient lithium cobalt phosphate samples have the best performance.
Fig. 6 is a diagram of the full-electric high-temperature storage performance of the matrix lithium cobaltate, the sample 1, the sample 2 and the sample 4, the test method is the same as that of the example 1, and it can be seen from fig. 6 that the high-temperature storage performance of the lithium-deficient lithium cobalt phosphate coated sample is obviously superior to that of the matrix lithium cobaltate, the lithium cobalt phosphate and the lithium-deficient lithium cobalt phosphate sample.
Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The use of "first," "second," and similar terms in the present application do not denote any order, quantity, or importance, but rather the terms are used to distinguish one element from another. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships are changed accordingly.
While the foregoing is directed to the preferred embodiment of the present invention, it will be appreciated by those skilled in the art that various changes and modifications may be made therein without departing from the principles of the invention as set forth in the appended claims.

Claims (8)

1. A lithium cobaltate composite material, comprising:
a substrate comprising lithium cobaltate;
the coating layer comprises lithium-deficient cobalt lithium phosphate and is coated on the surface of the substrate;
a transition layer comprising lithium cobaltate in a lithium deficient state intermediate the substrate and the cladding layer;
the coating layer comprises:
a first lithium cobalt phosphate layer, the first lithium cobalt phosphate layer coveringOn the surface of the transition layer or the substrate, the chemical formula of lithium-deficient cobalt lithium phosphate in the first lithium cobalt phosphate layer is Lix2CoPO4Wherein 0.3<x2<0.7；
The second lithium cobalt phosphate layer is coated on the surface of the first lithium cobalt phosphate layer, the first lithium cobalt phosphate layer is lithium-deficient lithium cobalt phosphate, and the chemical formula of the lithium-deficient lithium cobalt phosphate in the second lithium cobalt phosphate layer is Lix3CoPO4Wherein 0.3<x3<0.7, and x3< x2。
2. The composite material according to claim 1, wherein the coating layer has a thickness of 0.1 to 5nm, and/or
The thickness of the transition layer is 0.1-10 nm.
3. The composite material of claim 1, wherein the lithium cobaltate in the lithium deficient state has the formula Liy1CoO2Wherein, 0.3<y1<0.9。
4. The composite material according to claim 1, wherein the particle size of the lithium cobaltate composite material is 12 to 18 μm.
5. The method for producing a lithium cobaltate composite material according to any one of claims 1 to 4, wherein the method comprises:
providing nanoscale lithium-deficient cobalt lithium phosphate LixCoPO4，0.3<x<0.7；
Mixing the nanoscale lithium-deficient cobalt lithium phosphate with lithium cobaltate, wherein the mass of the lithium-deficient cobalt lithium phosphate is 0.02-2% of that of the lithium cobaltate, and performing heat treatment after mixing to obtain the lithium cobaltate composite material.
6. The preparation method as claimed in claim 5, wherein the temperature of the heat treatment is 700-1000 ℃, and the time of the heat treatment is 5-15 h.
7. A positive electrode material comprising the lithium cobaltate composite material according to any one of claims 1 to 4.
8. A battery comprising the positive electrode material according to claim 7.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105938917A (en) * 2016-07-01 2016-09-14 深圳市振华新材料股份有限公司 Lithium ion secondary cell lithium cobaltate cathode material, manufacture method and application thereof
CN106654224A (en) * 2017-01-16 2017-05-10 湖南瑞翔新材料股份有限公司 Lithium cobaltate composite material and preparation method thereof as well as positive electrode material
CN109417165A (en) * 2016-11-22 2019-03-01 株式会社Lg化学 Including core and the positive electrode active materials particle of shell of phosphoric acid cobalt lithium and preparation method thereof containing lithium and cobalt oxides
CN111293286A (en) * 2018-12-07 2020-06-16 湖南杉杉新能源有限公司 Coating modified lithium ion battery anode material and preparation method thereof

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1994587B1 (en) * 2006-03-20 2018-07-11 LG Chem, Ltd. Stoichiometric lithium cobalt oxide and method for preparation of the same
CN111293285A (en) * 2018-12-07 2020-06-16 湖南杉杉新能源有限公司 Coating modified lithium ion battery anode material and preparation method thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105938917A (en) * 2016-07-01 2016-09-14 深圳市振华新材料股份有限公司 Lithium ion secondary cell lithium cobaltate cathode material, manufacture method and application thereof
CN109417165A (en) * 2016-11-22 2019-03-01 株式会社Lg化学 Including core and the positive electrode active materials particle of shell of phosphoric acid cobalt lithium and preparation method thereof containing lithium and cobalt oxides
CN106654224A (en) * 2017-01-16 2017-05-10 湖南瑞翔新材料股份有限公司 Lithium cobaltate composite material and preparation method thereof as well as positive electrode material
CN111293286A (en) * 2018-12-07 2020-06-16 湖南杉杉新能源有限公司 Coating modified lithium ion battery anode material and preparation method thereof

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