阅读说明：本技术 一种钴酸锂正极材料及其制备方法 (Lithium cobaltate positive electrode material and preparation method thereof ) 是由 白珍辉 安娜 凌仕刚 沙金 苏迎春 朱卫泉 于 2019-10-31 设计创作，主要内容包括：本发明公开了一种钴酸锂正极材料及其制备方法,该钴酸锂正极材料的制备方法包括：将钴源和锂源混合,进行一次合成,得到产物A；将产物A分散在有机溶剂中,得到悬浊液；将悬浊液放入到微波消解仪中进行处理,得到产物B；对产物B进行后处理得到钴酸锂正极材料,本发明采用微波的方法对钴酸锂正极材料进行改性,所得的钴酸锂正极材料颗粒均匀,以该钴酸锂正极材料制备的锂离子电池的比容量较高和循环性能优异,且该制备方法工艺简单、无污染且能耗低,具有广阔的应用前景。(The invention discloses a lithium cobaltate positive electrode material and a preparation method thereof, wherein the preparation method of the lithium cobaltate positive electrode material comprises the following steps: mixing a cobalt source and a lithium source, and carrying out primary synthesis to obtain a product A; dispersing the product A in an organic solvent to obtain a suspension; putting the suspension into a microwave digestion instrument for treatment to obtain a product B; the product B is subjected to post-treatment to obtain the lithium cobaltate cathode material, the lithium cobaltate cathode material is modified by a microwave method, the obtained lithium cobaltate cathode material has uniform particles, a lithium ion battery prepared from the lithium cobaltate cathode material has high specific capacity and excellent cycle performance, and the preparation method has the advantages of simple process, no pollution, low energy consumption and wide application prospect.)

1. A preparation method of a lithium cobaltate positive electrode material is characterized by comprising the following steps:

step 1, mixing a cobalt source and a lithium source, and carrying out primary synthesis to obtain a product A;

step 2, dispersing the product A in an organic solvent to obtain a suspension;

step 3, putting the suspension into a microwave digestion instrument for treatment to obtain a product B;

and 4, carrying out post-treatment on the product B to obtain the lithium cobaltate positive electrode material.

2. The production method according to claim 1, wherein in step 1, the cobalt source is a cobalt compound, the lithium source is a lithium compound, and a molar ratio Li/Co of a Li element in the lithium source to a Co element in the cobalt source is (1 to 1.2): 1.

3. the method according to claim 1, wherein in step 4, the lithium source is one or more selected from lithium carbonate, lithium nitrate, lithium hydroxide, lithium oxalate, lithium acetate, lithium oxide and lithium chloride.

4. The preparation method according to claim 1, wherein the temperature of the primary synthesis in step 1 is 800-1050 ℃, preferably 900-1050 ℃.

5. The preparation method according to claim 1, wherein in the step 2, the organic solvent is one or more selected from ethanol, methanol, acetone, ethylene glycol and glycerol, and the weight ratio of the product A to the organic solvent is 1: (5-20), preferably 1: (8-15).

6. The preparation method according to claim 1, wherein in the step 3, the microwave digestion instrument is a high-throughput microwave digestion extraction synthesis workstation.

7. The preparation method according to claim 1, wherein in the step 3, the treatment temperature is 100-400 ℃ and the treatment time is 10-90 min in a microwave digestion instrument.

8. The method according to claim 1, wherein in step 4, the lithium cobaltate positive electrode material has a median particle diameter D₅₀2 to 10 μm.

9. The method according to claim 1, wherein the lithium cobaltate positive electrode material has a median particle diameter D₅₀Is 3 to 8 μm.

10. A lithium cobaltate positive electrode material prepared according to the method of one of claims 1 to 9.

Technical Field

The invention belongs to the technical field of lithium ion secondary batteries, and particularly relates to a lithium cobaltate positive electrode material and a preparation method thereof.

Background

The lithium ion battery has the advantages of high energy density, high working voltage, long cycle life, no memory effect, environmental friendliness and the like, and is widely applied to portable electronic equipment such as mobile phones, notebook computers, digital cameras and the like and electric automobiles.

With the rapid development of science and technology, 3C electronic products such as mobile phones gradually develop towards miniaturization and multi-functionalization, higher requirements are put forward on the service life and service life of lithium ion batteries, and simultaneously higher requirements are put forward on the cycle performance of the anode material.

Disclosure of Invention

In order to overcome the above problems, the present inventors have conducted intensive studies to design a lithium cobaltate positive electrode material and a method for preparing the same, the method for preparing the lithium cobaltate positive electrode material comprising: mixing a cobalt source and a lithium source, and carrying out primary synthesis to obtain a product A; dispersing the product A in an organic solvent to obtain a suspension; putting the suspension into a microwave digestion instrument for treatment to obtain a product B; the product B is post-processed to obtain the lithium cobaltate cathode material, the lithium cobaltate cathode material is modified by a microwave method, the obtained lithium cobaltate cathode material has uniform particles, a lithium ion battery prepared from the lithium cobaltate cathode material has high specific capacity and excellent cycle performance, and the preparation method has the advantages of simple process, no pollution, low energy consumption and wide application prospect, thereby completing the invention.

The invention aims to provide a preparation method of a lithium cobaltate positive electrode material, which comprises the following steps:

step 1, mixing a cobalt source and a lithium source, and carrying out primary synthesis to obtain a product A;

step 2, dispersing the product A in an organic solvent to obtain a suspension;

step 3, putting the suspension into a microwave digestion instrument for treatment to obtain a product B;

and 4, carrying out post-treatment on the product B to obtain the lithium cobaltate positive electrode material.

In the step 1, the cobalt source is a cobalt compound, the lithium source is a lithium compound, and the molar ratio of Li element in the lithium source to Co element in the cobalt source, Li/Co, is (1-1.2): 1.

in the step 4, the lithium source is one or more selected from lithium carbonate, lithium nitrate, lithium hydroxide, lithium oxalate, lithium acetate, lithium oxide and lithium chloride.

In the step 1, the temperature of the primary synthesis is 800-1050 ℃, and preferably 900-1050 ℃.

In the step 2, the organic solvent is one or more selected from ethanol, methanol, acetone, ethylene glycol and glycerol, and the weight ratio of the product A to the organic solvent is 1: (5-20), preferably 1: (8-15).

And in the step 3, the microwave digestion instrument is a high-flux microwave digestion extraction synthesis workstation.

In the step 3, in a microwave digestion instrument, the treatment temperature is 100-400 ℃, and the treatment time is 10-90 min.

In step 4, the median particle diameter D of the lithium cobaltate cathode material₅₀2 to 10 μm.

Wherein the lithium cobaltate cathode material has a median particle diameter D₅₀Is 3 to 8 μm.

Another aspect of the present invention provides a lithium cobaltate positive electrode material prepared by the method according to the first aspect of the present invention.

The invention has the following beneficial effects:

(1) the preparation method of the lithium cobaltate positive electrode material is also a modification method of the lithium cobaltate positive electrode material, and the lithium cobaltate material is subjected to microwave modification by adopting a high-throughput microwave digestion extraction synthesis workstation, so that the cycle performance of the lithium cobaltate positive electrode material is improved;

(2) the lithium cobaltate positive electrode material prepared by the method has uniform particles and good dispersibility, and the gram capacity and the cycle performance are superior to those of the traditional lithium cobaltate positive electrode material (which is not processed by a microwave digestion instrument), for example, the capacity retention rate of a lithium ion battery prepared by the lithium cobaltate positive electrode material under the conditions of 25 ℃ and 4.65V for 50 weeks is improved by more than 10 percent compared with that of the traditional lithium cobaltate positive electrode material, the cycle performance of the lithium cobaltate positive electrode material is obviously improved, and the service life of the lithium cobaltate positive electrode material is prolonged;

(3) under the conditions that the temperature is 25 ℃ and the voltage is 4.65V, the capacity retention rate of the lithium cobaltate cathode material prepared by the method is more than 85%, preferably more than 87%, more preferably more than 88% and even reaches 88.87% after 50-week circulation;

(4) the preparation method of the lithium cobaltate cathode material provided by the invention has the advantages of simple process, no pollution, low energy consumption and suitability for large-scale popularization.

Drawings

Fig. 1 shows an SEM image of the lithium cobaltate positive electrode material obtained in example 1;

fig. 2 shows an SEM image of the lithium cobaltate positive electrode material obtained in comparative example 1;

FIG. 3 shows specific discharge capacity versus cycle number curves for coin cells prepared from the lithium cobaltate positive electrode materials obtained in example 1 and comparative example 1;

fig. 4 shows the capacity retention rate of coin cells prepared from the lithium cobaltate positive electrode materials obtained in example 1 and comparative example 1 as a function of cycle number.

Detailed Description

The invention is explained in more detail below with reference to the drawings and preferred embodiments. The features and advantages of the present invention will become more apparent from the description.

The invention provides a preparation method of a lithium cobaltate positive electrode material on one hand, which comprises the following steps:

step 1, mixing a cobalt source and a lithium source, and carrying out primary synthesis to obtain a product A.

According to the present invention, in step 1, the cobalt source is a cobalt-containing compound, preferably one or more selected from cobaltosic oxide, cobalt hydroxide, cobalt carbonate, cobalt nitrate and cobalt chloride, more preferably cobaltosic oxide or cobalt carbonate, such as cobaltosic oxide.

According to the present invention, in step 1, the lithium source is a lithium-containing compound, preferably one or more of lithium carbonate, lithium nitrate, lithium hydroxide, lithium oxalate, lithium acetate, lithium oxide and lithium chloride, more preferably lithium carbonate or lithium hydroxide, such as lithium carbonate.

According to the present invention, in step 1, the particle size of the lithium source is in the nanometer range; the particle size of the cobalt source is 1-8 μm, preferably 4-5 μm, and the lithium source with the particle size can be selected to enable the finally prepared anode material to have the advantage of high compaction density, so that the obtained anode material is high in specific capacity and good in cycle performance.

According to the present invention, the cobalt source and the lithium source are mixed, and the mixing manner is not particularly limited, but is preferably a mixing manner commonly used in the art.

According to the invention, the cobalt source and the lithium source are mixed by high-speed mixing and/or ball-milling, for example in a high-speed mixer and/or a planetary ball mill.

According to the present invention, in step 1, the molar ratio of Li element in the lithium source to Co element in the cobalt source, Li/Co, is (1 to 1.2): 1, preferably, Li/Co ═ (1 to 1.1): 1, more preferably, Li/Co ═ (1 to 1.02): 1.

according to the present invention, in step 1, it is preferable that the lithium source and the cobalt source are uniformly mixed in a dry condition, and it is preferable that high speed mixing is performed and then ball milling mixing is performed.

According to the invention, the mixing speed of high-speed mixing is 1000-2000 r/min, preferably 1200-1800 r/min, and more preferably 1500 r/min; the mixing time is 30 to 150 seconds, preferably 50 to 120 seconds, and more preferably 80 seconds.

According to the invention, the mixing speed of ball milling mixing is 600-1000 r/min, preferably 700-900 r/min, and more preferably 850 r/min; the mixing time is 1-5 h, preferably 2-4 h, and more preferably 3 h.

According to a preferred embodiment of the present invention, in step 1, a dopant is further added, and the dopant is mixed with a lithium source and a cobalt source, wherein the dopant contains Mg element, preferably one or more of magnesium carbonate, magnesium nitrate and magnesium hydroxide.

According to a further preferred embodiment of the present invention, the molar ratio of Mg element in the dopant to Co element in the cobalt source is (0 to 0.01): 1.

according to the invention, the Mg-containing dopant is added to improve the cycle performance, such as cycle retention rate and cycle stability, of the final product lithium cobaltate cathode material.

According to the invention, in the step 1, a cobalt source and a lithium source are uniformly mixed and then subjected to one-time synthesis, wherein the one-time synthesis (high-temperature calcination) is performed in a high-temperature calcination process, the temperature of the one-time synthesis (high-temperature calcination) is 800-1050 ℃, preferably 900-1050 ℃, more preferably 950 ℃, and the calcination time is 6-12 hours, preferably 8-10 hours, for example 8 hours.

According to the present invention, in step 1, the primary synthesis is performed in an oxygen atmosphere, preferably an oxygen atmosphere having an oxygen concentration of 90% or more, preferably 95% or more, and more preferably 97% or more. For example, the primary synthesis is carried out in a muffle furnace.

According to the invention, in the step 1, the lithium source and the cobalt source are mixed and synthesized at one time to obtain the product A, and the product A is modified to obtain the lithium cobaltate cathode material with excellent cycle performance.

The inventor finds that the product A is processed by the microwave digestion instrument, so that the cycle performance of the lithium cobaltate anode material can be improved, and the microwave digestion instrument can rapidly and uniformly heat the product A under the microwave condition, so that the product A is modified.

And 2, dispersing the product A in an organic solvent to obtain a suspension.

In the invention, in step 2, when the product A is subjected to microwave digestion, the product A needs to be prepared and dispersed in an organic solvent to prepare a suspension.

According to the present invention, in step 2, the organic solvent is preferably selected from one or more of ethanol, methanol, acetone, ethylene glycol and glycerol, preferably ethanol, such as absolute ethanol.

According to the invention, in step 2, the dispersing mode is preferably ultrasonic dispersing, preferably, the power of the ultrasonic dispersing is 600W, and the frequency of the ultrasonic is 40000 Hz; the ultrasonic dispersion time is 5-60 min, preferably 10-30 min, and more preferably 10 min. The power and frequency are inherent to the apparatus and a uniform and useful suspension is obtained at the dispersion time.

According to the invention, in step 2, the mass ratio of the product A to the organic solvent is 1: (5-20), preferably 1: (8-15), for example, 1:10, the product A can be dispersed well. When the mass ratio of the two components is too large, the dispersion tends to be uneven, and when the mass ratio is too small, the experiment speed is affected.

And 3, putting the suspension into a microwave digestion instrument for treatment to obtain a product B.

According to the invention, in the step 3, the suspension of the product A obtained in the step 2 is placed into a microwave digestion instrument for treatment, and is taken out after the treatment is finished and the cooling is carried out, so as to obtain a product B, wherein the microwave digestion instrument is preferably a high-flux microwave digestion extraction synthesis workstation, preferably the model is SINEO MDS-10, the suspension is added into a digestion tank of the high-flux microwave digestion extraction synthesis workstation, absolute ethyl alcohol with the same mass as the solvent in the digestion tank is added into a main control tank, and the liquid level of the absolute ethyl alcohol is not more than two thirds of that of a reaction tank.

According to the invention, in the step 3, the suspension is treated in a microwave digestion instrument, wherein the treatment temperature is 100-400 ℃, preferably 200-350 ℃, and more preferably 300 ℃; and/or

The treatment time is 10-90 min, preferably 20-60 min, such as 30 min; and/or

The processing power is 2000-3000W, preferably 2500W.

According to the invention, the microwave digestion instrument can carry out microwave digestion on the product A in the suspension, so that rapid and uniform heating is realized, the product A is crushed, the granularity of the product A is reduced, the particles are more uniform, the dispersibility is good, and the capacity and the cycle retention rate of the final lithium cobaltate anode material are improved.

And 4, carrying out post-treatment on the product B to obtain the lithium cobaltate positive electrode material.

According to the invention, in step 4, the post-treatment of the product B comprises drying, crushing and sieving the product B.

According to the invention, the product B is dried by adopting a drying mode commonly used in the field, the pulverization is preferably carried out by air flow pulverization, and the sieving mesh number is preferably 200-500 meshes, for example 300 meshes, so as to obtain the lithium cobaltate cathode material.

According to the invention, a product A is obtained through one-time synthesis, wherein the product A is an unmodified lithium cobaltate positive electrode material, and then the product A is modified through a microwave treatment method, so that the obtained lithium cobaltate positive electrode material is a microwave modified lithium cobaltate positive electrode material.

According to the invention, in the step 4, the particle size distribution range of the obtained lithium cobaltate positive electrode material is 1-15 μm. Median particle diameter D of obtained lithium cobaltate cathode material₅₀2 to 10 μm, preferably 3 to 8 μm, and more preferably (5. + -. 0.5) μm.

The lithium cobaltate positive electrode material obtained by the preparation method provided by the invention has uniform particles and good dispersibility, and the gram capacity and the cycle performance are superior to those of the traditional lithium cobaltate positive electrode material (which is not processed by a microwave digestion instrument), for example, the cycle retention rate of a lithium ion battery prepared from the lithium cobaltate positive electrode material prepared by the invention after 50 cycles at 25 ℃ and 4.65V is improved by more than 10% compared with that of the traditional lithium cobaltate positive electrode material, the cycle performance of the lithium cobaltate positive electrode material is obviously improved, and the service life of the lithium cobaltate positive electrode material is prolonged.

A second aspect of the present invention provides a lithium cobaltate positive electrode material, preferably prepared by the method of the first aspect of the present invention.

The lithium ion battery prepared from the lithium cobaltate positive electrode material obtained by the preparation method has the cycle retention rate of more than 85%, preferably more than 87%, more preferably more than 88% and even up to 88.18% after 50 weeks of cycle under the conditions of 25 ℃ and 4.65V of voltage.

Examples

Example 1(

Weighing 400g of dried cobaltosic oxide and 186.8g of lithium carbonate, adding the weighed materials into a high-speed mixer, mixing the materials at a high speed for 80s at a rotating speed of 1500r/min, then adding the materials into a planetary ball mill for uniform mixing, ball-milling and mixing the materials at a rotating speed of 850r/min for 3h, after the mixing is finished, putting the mixture into a muffle furnace for primary synthesis, and calcining the mixture at a high temperature of 950 ℃ for 8h to obtain a product A;

adding 50g of the product A into 400g of absolute ethyl alcohol, and performing ultrasonic treatment to obtain a suspension;

and (3) moving the suspension into a digestion tank of a high-flux microwave digestion extraction synthesis workstation, adding absolute ethyl alcohol with equal mass into a main control tank, setting the processing temperature of the microwave digestion workstation to be 300 ℃ and the processing time to be 30min, setting the processing temperature of the microwave digestion workstation to be 300 ℃, moving out of the workstation after cooling, and obtaining a product B.

And drying the product B, and screening the product B through a 300-mesh sieve after jet milling to obtain the final product lithium cobaltate cathode material.

Scanning electron microscope test is carried out on the obtained lithium cobaltate positive electrode material, the obtained SEM image is shown in figure 1, as can be seen from figure 1, the obtained lithium cobaltate positive electrode material has uniform particles, good dispersibility and particle size distribution of 1.657-11.198 microns, and D of the lithium cobaltate positive electrode material is measured₅₀4.706 μm. The agglomeration of the positive electrode material particles is opened, and the particle size is reduced. The obtained positive electrode material has improved compaction density, and the capacity and the cycle retention rate of the obtained positive electrode material can be improved.

Example 2

Weighing 400g of dried cobaltosic oxide and 186.8g of lithium carbonate, adding the weighed materials into a high-speed mixer, mixing the materials at a high speed for 70s at a rotating speed of 1600r/min, then adding the materials into a planetary ball mill for uniform mixing, ball-milling and mixing the materials at a rotating speed of 850r/min for 3h, after the mixing is finished, putting the mixture into a muffle furnace for one-time synthesis, and calcining the mixture at a high temperature of 950 ℃ for 8h to obtain a product A;

adding 50g of the product A into 400g of absolute ethyl alcohol, and performing ultrasonic treatment to obtain a suspension;

and (3) moving the suspension into a digestion tank of a high-flux microwave digestion extraction synthesis workstation, adding absolute ethyl alcohol with equal mass into a main control tank, setting the processing temperature of the microwave digestion workstation to be 300 ℃ and the processing time to be 20min, setting the processing temperature of the microwave digestion workstation to be 300 ℃, moving out of the workstation after cooling, and obtaining a product B.

And drying the product B, and screening the product B through a 300-mesh sieve after jet milling to obtain the final product lithium cobaltate cathode material.

Scanning electron microscope testing is carried out on the obtained lithium cobaltate positive electrode material, the obtained lithium cobaltate positive electrode material is uniform in particle, good in dispersity and 1.657-11.2 mu m in particle size distribution, and the D of the lithium cobaltate positive electrode material is measured₅₀4.719 μm.

Example 3()

Weighing 400g of dried cobaltosic oxide and 186.8g of lithium carbonate, adding the weighed materials into a high-speed mixer, mixing the materials at a high speed for 80s at a rotating speed of 1500r/min, then adding the materials into a planetary ball mill for uniform mixing, ball-milling and mixing the materials at a rotating speed of 850r/min for 3h, after the mixing is finished, putting the mixture into a muffle furnace for primary synthesis, and calcining the mixture at a high temperature of 950 ℃ for 8h to obtain a product A;

adding 50g of the product A into 400g of absolute ethyl alcohol, and performing ultrasonic treatment to obtain a suspension;

and (3) moving the suspension into a digestion tank of a high-flux microwave digestion extraction synthesis workstation, adding 400g of absolute ethyl alcohol into a main control tank, setting the processing temperature of the microwave digestion workstation to 400 ℃ and the processing time to 30min, setting the processing temperature of the microwave digestion workstation to 400 ℃, cooling, and moving out of the workstation to obtain a product B.

And drying the product B, and screening the product B through a 300-mesh sieve after jet milling to obtain the final product lithium cobaltate cathode material.

Scanning electron microscope testing is carried out on the obtained lithium cobaltate positive electrode material, the obtained lithium cobaltate positive electrode material has uniform particles, good dispersibility and particle size of 1.288-14.371 mu m, and D of the lithium cobaltate positive electrode material is measured₅₀4.171 μm.

Example 4

Weighing 400g of dried cobaltosic oxide and 186.8g of lithium carbonate, adding the weighed materials into a high-speed mixer, mixing the materials at a high speed for 80s at a rotating speed of 1600r/min, then adding the materials into a planetary ball mill, uniformly mixing the materials, mixing the materials for 3 hours at a mixing speed of 850r/min, putting the mixture into a muffle furnace for one-time synthesis after the mixture is mixed, and calcining the mixture at a high temperature of 1000 ℃ for 8 hours to obtain a product A;

adding 50g of the product A into 400g of absolute ethyl alcohol, and performing ultrasonic treatment to obtain a suspension;

and (3) moving the suspension into a digestion tank of a high-flux microwave digestion extraction synthesis workstation, adding 400g of absolute ethyl alcohol into a main control tank, setting the processing temperature of the microwave digestion workstation to 300 ℃ and the processing time to 30min, setting the processing temperature of the microwave digestion workstation to 300 ℃, moving out of the workstation after cooling, and obtaining a product B.

And drying the product B, and screening the product B through a 300-mesh sieve after jet milling to obtain the final product lithium cobaltate cathode material.

And (3) performing scanning electron microscope test on the obtained lithium cobaltate positive electrode material, wherein the obtained lithium cobaltate positive electrode material has uniform particles, good dispersibility and particle size of 1.654-12.723 mu m, and measuring the D of the lithium cobaltate positive electrode material₅₀4.978 μm.

Example 5

Weighing 400g of dried cobaltosic oxide and 186.8g of lithium carbonate, adding the weighed materials into a high-speed mixer, mixing the materials at a high speed for 80s at a rotating speed of 1500r/min, then adding the materials into a planetary ball mill for uniform mixing, ball-milling and mixing the materials at a rotating speed of 850r/min for 3h, after the mixing is finished, putting the mixture into a muffle furnace for primary synthesis, and calcining the mixture at a high temperature of 850 ℃ for 8h to obtain a product A;

adding 50g of the product A into 400g of absolute ethyl alcohol, and performing ultrasonic treatment to obtain a suspension;

and (3) moving the suspension into a digestion tank of a high-flux microwave digestion extraction synthesis workstation, adding 400g of absolute ethyl alcohol into a main control tank, setting the processing temperature of the microwave digestion workstation to be 300 ℃ and the processing time to be 30min, setting the processing temperature of the microwave digestion workstation to be 300 ℃, moving out of the workstation after cooling, and obtaining a product B.

And drying the product B, and screening the product B through a 300-mesh sieve after jet milling to obtain the final product lithium cobaltate cathode material.

Scanning electron microscope testing is carried out on the obtained lithium cobaltate positive electrode material, the obtained lithium cobaltate positive electrode material has uniform particles, good dispersibility and particle size of 1.48-10.055 mu m, and D of the lithium cobaltate positive electrode material is measured₅₀It was 4.337. mu.m.

Comparative example

Comparative example 1

Weighing 400g of dried cobaltosic oxide and 186.8g of lithium carbonate, adding the weighed materials into a high-speed mixer, mixing the materials at a high speed for 80s at a rotating speed of 1500r/min, then adding the materials into a planetary ball mill for uniform mixing, ball-milling and mixing the materials at a rotating speed of 850r/min for 3h, after the mixing is finished, putting the mixture into a muffle furnace for primary synthesis, and calcining the mixture at a high temperature of 950 ℃ for 8h to obtain a product A.

The product A is used as the final product lithium cobaltate cathode material obtained in the comparative example 1.

The obtained lithium cobaltate cathode material is subjected to scanning electron microscope test, the obtained SEM image is shown in fig. 2, and as can be seen from fig. 2, the obtained cathode material has a larger particle size.

Examples of the experiments

The lithium cobaltate positive electrode materials obtained in the embodiment 1 and the comparative example 1 are respectively used as the positive electrode of the lithium ion battery, the lithium sheet is used as the negative electrode, the button battery is assembled, a blue-electricity system is adopted for testing, the specific capacity and the cycle retention rate of the battery after 50 times of charge and discharge cycles are tested under the conditions that the temperature is 25 ℃ and the voltage is 4.65V, the relation curve of the discharge specific capacity and the cycle frequency of the obtained battery is shown in figure 3, and the relation curve of the cycle retention rate and the cycle frequency of the obtained battery is shown in figure 4.

As can be seen from fig. 3, the specific discharge capacity of the battery prepared from the lithium cobaltate positive electrode material obtained in example 1 is higher than that of the battery prepared from the lithium cobaltate positive electrode material obtained in comparative example 1, the specific discharge capacities of the batteries prepared from the lithium cobaltate positive electrode materials obtained in example 1 and comparative example 1 are 205.6mAh/g and 204.3mAh/g, respectively, the specific discharge capacity of the battery prepared from the lithium cobaltate positive electrode material obtained in comparative example 1 decreases rapidly with the increase of the cycle number, and after 50 cycles, the specific discharge capacity of the battery prepared from the lithium cobaltate positive electrode material obtained in example 1 is 181.3mAh/g, while the specific discharge capacity of the battery prepared from the lithium cobaltate positive electrode material obtained in comparative example 1 is 150.5 mAh/g.

As can be seen from fig. 4, the capacity retention ratio of the battery prepared from the lithium cobaltate positive electrode material obtained in example 1 was higher than that of comparative example 1. The cycle retention rate of the battery prepared from the lithium cobaltate positive electrode material in the comparative example 1 is reduced faster with the increase of the cycle number, and after 50 cycles, the capacity retention rate of the battery prepared from the lithium cobaltate positive electrode material obtained in the example 1 is 88.18%, while the capacity retention rate of the battery prepared from the lithium cobaltate positive electrode material in the comparative example 1 is 73.64%.

The invention has been described in detail with reference to the preferred embodiments and illustrative examples. It should be noted, however, that these specific embodiments are only illustrative of the present invention and do not limit the scope of the present invention in any way. Various modifications, equivalent substitutions and alterations can be made to the technical content and embodiments of the present invention without departing from the spirit and scope of the present invention, and these are within the scope of the present invention. The scope of the invention is defined by the appended claims.