CN108550802B - Y/La-doped Co/B Co-coated nickel-cobalt-manganese ternary positive electrode material and preparation method thereof - Google Patents

Abstract

The invention is suitable for the technical field of lithium batteries, and provides a Y/La doped Co/B co-coated nickel-cobalt-manganese ternary positive electrode material and a preparation method. The invention adopts a small amount of Y3+ ions and La3+ ions to improve the cycle. Performance and safety performance, since Y3+/La3+ has the same valence state as Ni3+, the doped Y3+/La3+ can enter the metal Ni3+ site, and Y3+/La3+ does not change its valence during charge and discharge, and is electrochemically inert. There is no change in valence state during discharge, so there is no change in volume, which can play the role of a skeleton, stabilize the crystal structure, and improve the cycle life and safety performance of the material; in addition, Co/B coats the cathode material under high voltage. It can also effectively improve the cycle performance and electronic conductivity of the battery, reduce residual alkali, and reduce flatulence. Therefore, the co-coated nickel-cobalt-manganese ternary positive electrode material provided by the present invention can prevent the occurrence of side reactions in a very effective way, so as to improve the lithium battery. cycle performance and electrochemical performance.

Description

A Y/La-doped Co/B co-coated nickel-cobalt-manganese ternary positive electrode material and preparation method

technical field

The invention belongs to the technical field of lithium batteries, in particular to a nickel-cobalt-manganese ternary positive electrode material co-coated with Y/La doped Co/B and a preparation method thereof.

Background technique

High-nickel nickel-cobalt-manganese ternary lithium-ion battery cathode materials are widely used in HEV and PHEV new energy vehicles due to their low cost, low toxicity, and high energy density. However, during the charging and discharging process of pure nickel-cobalt manganate, Ni ²⁺ can easily enter the Li layer, resulting in serious mixing, and the Li ions are not easily de-intercalated, which causes great harm to the cycle life and safety of the material. In addition, when the positive electrode material is in contact with the electrolyte, a side reaction occurs, the thermal stability becomes poor, and the Ni ⁴⁺ becomes unstable during the process of Li removal.

SUMMARY OF THE INVENTION

In view of the above-mentioned problems, the object of the present invention is to provide a kind of Y/La doped Co/B co-coated nickel-cobalt-manganese ternary positive electrode material and preparation method, aiming to solve the cycle performance of the existing nickel-manganese manganese ternary positive electrode material and technical issues with poor rate performance.

On the one hand, the preparation method of the Y/La-doped Co/B co-coated nickel-cobalt-manganese ternary positive electrode material comprises the following steps:

Step S1, taking by weighing the nickel-cobalt-manganese precursor;

Step S2, according to the metal content of nickel, cobalt and manganese in the nickel-cobalt-manganese precursor, weigh a certain amount of compounds containing Y and La and a certain amount of lithium source compounds according to the expected ratio;

Step S3, adding the compound containing Y and La together with the nickel-cobalt-manganese precursor and the lithium source compound into a high-speed mixer to fully mix, and then calcining to obtain a doped matrix material;

Step S4, adding the doped base material into deionized water and stirring evenly, and then adding cobalt salt dropwise to continue stirring to obtain a positive electrode material slurry coated with cobalt hydroxide;

Step S5, filtering, washing and drying the positive electrode material slurry to obtain a positive electrode material powder coated with cobalt hydroxide;

Step S6, mixing the cobalt hydroxide-coated positive electrode material powder with lithium salt and performing secondary sintering to obtain a lithium cobalt oxide-coated positive electrode material;

Step S7, adding the B source compound and the lithium cobalt oxide-coated positive electrode material into a high-speed mixer to fully mix, and then calcining to obtain a Y/La-doped Co/B co-coated nickel-cobalt-manganese trioxide. Element cathode material.

Further, in step S2, the doping molar amount of Y and La is 0.001-0.1% of the total molar amount of nickel, cobalt, and manganese in the nickel-cobalt-manganese precursor, and the compound containing Y and La is Y and La. One or more of oxides, carbonates and nitrates, the amount of the lithium source compound is calculated in molar ratio Li:Me=0.9-1.1:1, wherein Me is nickel, cobalt in the nickel-cobalt-manganese precursor , the total moles of manganese metal.

Further, in the calcination process of step S3, the calcination temperature is 700°C-900°C, and the calcination time is 10-25h.

Further, the cobalt salt added dropwise in step S4 is one or more of cobalt sulfate, cobalt acetate, cobalt oxalate, cobalt nitrate, and cobalt chloride, and the coating amount of cobalt element is 1000-5000 ppm.

Further, in the sintering process of step S6, the sintering temperature is 600°C-800°C, and the sintering time is 6h-12h.

Further, in step S7, the B source compound is one or both of boron-containing oxide and boric acid, and the coating amount of B element is 1000-3000 ppm.

Further, in the calcination process of step S7, the calcination temperature is 200°C-400°C, and the calcination time is 6h-12h.

On the other hand, in the Y/La-doped Co/B co-coated nickel-cobalt-manganese ternary cathode material, the inner layer is a doped matrix material doped with Y and La, and the outer layer is Co and B co-coated The coating layer, the Y/La-doped Co/B co-coated nickel-cobalt-manganese ternary positive electrode material is prepared by the aforementioned method.

The beneficial effects of the present invention are as follows: the solution of the present invention adopts a small amount of Y ³⁺ ions and La ³⁺ ions to improve the cycle performance and safety performance. Since the valence states of Y ³⁺ /La ³⁺ and Ni ³⁺ are the same, the The introduced Y ³⁺ /La ³⁺ can enter the metal Ni ³⁺ site, and Y ³⁺ /La ³⁺ does not change its valence during the charge and discharge process, and is electrochemically inert, and does not have a valence state during charge and discharge. changes in volume, so there is no change in volume, which can play the role of a skeleton, stabilize the crystal structure, and improve the cycle life and safety performance of the material; in addition, Co/B coating the cathode material at high voltage can also effectively improve the cycle of the battery. performance and electronic conductivity, reduce residual alkali, and reduce flatulence, so the co-coated nickel-cobalt-manganese ternary positive electrode material provided by the present invention can prevent the occurrence of side reactions in a very effective way, so as to improve the cycle performance and electrochemical performance of lithium batteries .

Description of drawings

FIG. 1 is a graph showing the discharge cycle of Example 1 and Comparative Example 1 at a 1C rate at a voltage of 2.75V to 4.3V.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

The preparation method of the Y/La-doped Co/B co-coated nickel-cobalt-manganese ternary positive electrode material provided by the present invention comprises the following steps:

Step S1, weighing the nickel-cobalt-manganese precursor.

The types of nickel-cobalt-manganese precursors are not limited here, such as NCM811, NCM523, NCM622, etc.

In step S2, according to the metal contents of nickel, cobalt and manganese in the nickel-cobalt-manganese precursor, weigh a certain amount of compound containing Y and La and a certain amount of lithium source compound according to the expected ratio.

Step S3, adding the compound containing Y and La together with the nickel-cobalt-manganese precursor and the lithium source compound into a high-speed mixer to fully mix, and then calcining to obtain a doped matrix material.

In this step, the nickel-cobalt-manganese precursor is mixed with the compound of Y and La and the lithium source compound, and then calcined to obtain the doped matrix material. In this step, the doping molar amount of Y and La is 0.001-0.1% of the total molar amount of nickel, cobalt and manganese in the nickel-cobalt-manganese precursor, and the compounds containing Y and La are oxides of Y, La, carbon One or more of acid salts and nitrates, the amount of the lithium source compound is calculated in molar ratio Li:Me=0.9-1.1:1, wherein Me is the moles of nickel, cobalt, and manganese in the nickel-cobalt-manganese precursor. total.

Step S4, adding the doped base material into deionized water and stirring evenly, and then adding cobalt salt dropwise to continue stirring to obtain a positive electrode material slurry coated with cobalt hydroxide.

The cobalt salt is one or more of cobalt sulfate, cobalt acetate, cobalt oxalate, cobalt nitrate, and cobalt chloride, and the coating amount of cobalt element is 1000-5000 ppm.

Step S5, filtering, washing and drying the positive electrode material slurry to obtain a positive electrode material powder coated with cobalt hydroxide.

Step S6, mixing the positive electrode material powder coated with cobalt hydroxide and lithium salt and performing secondary sintering to obtain a positive electrode material coated with lithium cobalt oxide.

In the sintering process in this step, the sintering temperature is 600°C-800°C, and the sintering time is 6h-12h.

Step S7, adding the B source compound and the lithium cobalt oxide-coated positive electrode material into a high-speed mixer to fully mix, and then calcining to obtain a Y/La-doped Co/B co-coated nickel-cobalt-manganese trioxide. Element cathode material.

The B source compound is one or both of boron-containing oxide and boric acid, and the coating amount of B element is 1000-3000 ppm. In this step, the calcination temperature is 200 ℃-400 ℃, and the calcination time is 6h-12h. Doped doped base material, the outer layer is a cladding layer co-coated by Co and B.

In order to verify the effect of the positive electrode material of the present invention, the following description will be given through specific implementation.

Example 1:

(1.1) Weigh 100g of Ni _0.83 Co _0.11 Mn _0.06 (OH) ₂ precursor, Y ₂ O ₃ (0.127g) with 0.1% doping content, and La ₂ O ₃ (0.117g), mix them evenly, and then add them to the hydroxide. Lithium and precursor powder were added to a high-speed mixer according to Li/(Ni+Co+Mn)=1.01:1.1 for mixing. In the atmosphere of oxygen, sintered at a low temperature of 500 °C for 240 min, heated to 800 °C at a high temperature for 720 min, cooled to 600 °C for 120 min, and naturally cooled to 100 °C to obtain a Y/La doped matrix material for primary sintering.

(1.2) Add 100g of Y/La doped base material sintered once to 40°C, 50g deionized water and stir for 10min, drop 1mol/L cobalt sulfate, stir for 10min, filter and wash, and dynamically dry on a rotary evaporator for 60min , after drying in a vacuum drying oven at 120°C for 480min, the positive electrode material powder coated with cobalt hydroxide was obtained, which was sintered at 700°C for 10 hours in an oxygen atmosphere, and then cooled to 100°C naturally to obtain a positive electrode material coated with lithium cobalt oxide. .

(1.3) After mixing 100 g of lithium cobalt oxide-coated cathode material with 0.1% by mass boron oxide, sintered at 250 °C for 12 h in an air atmosphere, and cooled to 100 °C naturally to obtain Y/La doped Co/B Co-coated nickel-cobalt-manganese ternary cathode material.

(1.4) Make a button cell and test its electrical properties.

The prepared Y/La-doped Co/B co-coated nickel-cobalt-manganese ternary cathode material Ni _0.83 Co _0.11 Mn _0.06 , the conductive agent acetylene carbon black, and the binder PVDF were mixed uniformly according to the mass ratio of 80:12:8 , adding an appropriate amount of 1-methyl-2-pyrrolidone and ball milling for 1 hour to prepare a slurry, which is evenly coated on the aluminum sheet, dried and pressed to make a positive electrode sheet. A 2032 button battery was assembled with metal lithium sheet as the negative electrode, and the electrical performance was tested by the Siken test system (the charging and discharging voltage was 2.75-4.3 V, and the high-voltage charging and discharging voltage was 2.75-4.4 V).

The results show that the first discharge capacity of the doped-coated lithium battery is 205mAh/g at 0.1C rate, the first effect is 89%, and the capacity retention rate is 98.4% after 50 cycles at 1C rate.

Comparative example 1:

(1.1) After weighing 100g of Ni _0.83 Co _0.11 Mn _0.06 (OH) ₂ precursor, lithium hydroxide and precursor powder were added to a high-speed mixer according to Li/(Ni+Co+Mn)=1.01:1.1 for mixing. Sintering at a low temperature of 500 °C for 240 min in an oxygen atmosphere, sintering at a high temperature of 800 °C for 720 min, cooling to 600 °C for 120 min, and natural cooling to 100 °C to obtain a primary sintered cathode material.

(1.2) 100 g of the primary sintered positive electrode material was sintered for 10 hours at 600° C. in an oxygen atmosphere, and then naturally cooled to 100° C. to obtain an ordinary lithium-ion battery positive electrode material.

(1.3) Make a button cell and test its electrical properties.

The prepared cathode material Ni _0.83 Co _0.11 Mn _0.06 for ordinary lithium ion batteries, acetylene carbon black as a conductive agent, and PVDF as a binder are mixed uniformly in a mass ratio of 80:12:8, and an appropriate amount of 1-methyl-2-pyrrolidone is added to ball mill 1 After hours, the slurry is evenly coated on the aluminum sheet, dried and pressed to form a positive electrode sheet. A 2032 button battery was assembled with metal lithium sheet as the negative electrode, and the electrical performance was tested by the Siken test system (the charging and discharging voltage was 2.75-4.3 V, and the high-voltage charging and discharging voltage was 2.75-4.4 V).

The results show that the first discharge capacity of the doped-coated lithium battery is 193.3mAh/g at 0.1C rate, the first effect is 81%, and the capacity retention rate is 93.4% after 50 cycles at 1C rate.

Embodiment 2:

(2.1) Weigh 100g Ni _0.80 Co _0.10 Mn _0.10 (OH) ₂ precursor, 0.1% doping amount of Y ₂ O ₃ (0.127g) and La ₂ O ₃ (0.117g), mix them evenly, and add them. The precursor powder was added to the high mixing equipment according to Li/(Ni+Co+Mn)=1.01:1.1 for mixing. In the atmosphere of oxygen, sintered at a low temperature of 500 °C for 240 min, heated to 800 °C at a high temperature for 720 min, cooled to 600 °C for 120 min, and naturally cooled to 100 °C to obtain a Y/La doped matrix material for primary sintering.

(2.2) Add 100g of Y/La doped base material sintered once to 40°C, 50g deionized water and stir for 10min, drop in 1mol/L cobalt oxalate, stir for 10min, filter and wash, and dynamically dry on a rotary evaporator for 60min After drying in a vacuum drying oven at 120°C for 480min, a positive electrode material powder coated with cobalt hydroxide was obtained, which was sintered at 700°C for 10 hours in an oxygen atmosphere, and then cooled to 100°C naturally to obtain a positive electrode material coated with lithium cobalt oxide.

(2.3) After mixing 100 g of lithium cobalt oxide-coated lithium ion battery cathode material with 0.1% mass ratio of boron oxide, sintered at 250 °C for 12 h in an air atmosphere, and naturally cooled to 100 °C to obtain Y/La doped Co/B co-coated nickel-cobalt-manganese ternary cathode material.

(2.4) Make a button cell and test its electrical properties.

The prepared Y/La-doped Co/B co-coated nickel-cobalt-manganese ternary positive electrode material Ni _0.80 Co _0.10 Mn _0.10 was mixed with the conductive agent acetylene carbon black and the binder PVDF according to the mass ratio of 80:12:8 Evenly, add an appropriate amount of 1-methyl-2-pyrrolidone and ball mill for 1 hour to prepare a slurry, which is evenly coated on the aluminum sheet, dried and pressed to form a positive electrode sheet. A 2032 button battery was assembled with metal lithium sheet as the negative electrode, and the electrical performance was tested by the Siken test system (the charging and discharging voltage was 2.75-4.3 V, and the high-voltage charging and discharging voltage was 2.75-4.4 V).

The results show that the first discharge capacity of the dopant-coated lithium battery is 200.8mAh/g at 0.1C rate, the first efficiency is 89.2%, and the capacity retention rate is 98.1% after 50 cycles at 1C rate.

Comparative example two :

(2.1) After weighing 100g of Ni _0.80 Co _0.10 Mn _0.10 (OH) ₂ precursor, lithium carbonate and precursor powder were added to a high-mixing device according to Li/(Ni+Co+Mn)=1.01:1.1 for mixing. Sintering at a low temperature of 500 °C for 240 min in an oxygen atmosphere, sintering at a high temperature of 800 °C for 720 min, cooling to 600 °C for 120 min, and natural cooling to 100 °C to obtain a primary sintered cathode material.

(2.2) 100 g of the primary sintered positive electrode material was sintered at 600° C. for 10 hours in an oxygen atmosphere, and then naturally cooled to 100° C. to obtain an ordinary lithium-ion battery positive electrode material.

(2.3) Make a button cell and test its electrical properties.

The common positive electrode material Ni _0.80 Co _0.10 Mn _0.10 , the conductive agent acetylene carbon black, and the binder PVDF are mixed uniformly according to the mass ratio of 80:12:8, and an appropriate amount of 1-methyl-2-pyrrolidone is added and ball milled for 1 hour to make a slurry The material is evenly coated on the aluminum sheet, dried and pressed to form a positive electrode sheet. A 2032 button battery was assembled with metal lithium sheet as the negative electrode, and the electrical performance was tested by the Siken test system (the charging and discharging voltage was 2.75-4.3 V, and the high-voltage charging and discharging voltage was 2.75-4.4 V).

The results show that the first discharge capacity of the doped-coated lithium battery is 190.2mAh/g at 0.1C rate, the first effect is 82%, and the capacity retention rate is 93% after 50 cycles at 1C rate.

Embodiment three:

(3.1) Weigh 100g Ni _0.60 Co _0.20 Mn _0.20 (OH) ₂ precursor, Y ₂ O ₃ (0.127g) with 0.1% doping content and La ₂ O ₃ (0.117g), mix them uniformly, and add them to the hydrogen peroxide. Lithium salt and precursor powder were added to a high-speed mixer according to Li/(Ni+Co+Mn)=1.01:1.1 for mixing. In the atmosphere of oxygen, sintered at a low temperature of 500 °C for 240 min, heated to 900 °C at a high temperature for 720 min, cooled to 600 °C for 120 min, and then naturally cooled to 100 °C to obtain a Y/La doped matrix material for primary sintering.

(3.2) Add 100g of Y/La doped base material sintered once to 40°C, 50g of deionized water and stir for 10min, drop 1mol/L Co salt, stir for 10min, filter and wash, and dynamically dry on a rotary evaporator After 60 min, drying in a vacuum drying oven at 120°C for 480min, secondary sintering at 700°C for 10h in an oxygen atmosphere, and cooling to 100°C naturally to obtain a cathode material coated with lithium cobalt oxide.

(3.3) After mixing 100 g of lithium cobalt oxide-coated cathode material with 0.1% boron oxide by mass, sintering at 250°C for 12h in an air atmosphere, and cooling down to 100°C naturally to obtain Y/La doped Co/B Co-coated nickel-cobalt-manganese ternary cathode material.

(3.4) Make a button cell and test its electrical properties.

The prepared Y/La-doped Co/B-coated cathode material Ni _0.60 Co _0.20 Mn _0.20 , the conductive agent acetylene carbon black, and the binder PVDF were mixed uniformly according to the mass ratio of 80:12:8, and an appropriate amount of 1- Methyl-2-pyrrolidone was ball-milled for 1 hour to prepare a slurry, which was evenly coated on the aluminum sheet, dried and pressed to form a positive electrode sheet. A 2032 button battery was assembled with metal lithium sheet as the negative electrode, and the electrical performance was tested by the Siken test system (the charging and discharging voltage was 2.75-4.3 V, and the high-voltage charging and discharging voltage was 2.75-4.4 V).

The results show that the first discharge capacity of the doped-coated lithium battery is 179.3mAh/g at 0.1C rate, the first efficiency is 90.2%, and the capacity retention rate is 98.8% after 50 cycles at 1C rate.

Comparative example three :

(3.1) After weighing 100g of Ni _0.60 Co _0.20 Mn _0.20 (OH) ₂ precursor, lithium hydroxide and precursor powder were added to a high-speed mixer according to Li/(Ni+Co+Mn)=1.01:1.1 for mixing. The cathode material was sintered at a low temperature of 500 °C for 240 min in an oxygen atmosphere, heated to 900 °C for 720 min, cooled to 600 °C for 120 min, and naturally cooled to 100 °C to obtain a primary sintered cathode material.

(3.2) 100 g of the primary sintered positive electrode material was sintered for 10 hours at 600° C. for 10 hours in an oxygen atmosphere, and then naturally cooled to 100° C. to obtain an ordinary lithium-ion battery positive electrode material.

(3.3) Make a button cell and test its electrical properties.

The common positive electrode material Ni _0.60 Co _0.20 Mn _0.20 , the conductive agent acetylene carbon black, and the binder PVDF are mixed uniformly according to the mass ratio of 80:12:8, and an appropriate amount of 1-methyl-2-pyrrolidone is added and ball milled for 1 hour to make a slurry The material is evenly coated on the aluminum sheet, dried and pressed to form a positive electrode sheet. A 2032 button battery was assembled with metal lithium sheet as the negative electrode, and the electrical performance was tested by the Siken test system (the charging and discharging voltage was 2.75-4.3 V, and the high-voltage charging and discharging voltage was 2.75-4.4 V).

The results show that the first discharge capacity of the doped-coated lithium battery is 173.6mAh/g at 0.1C rate, the first efficiency is 84.1%, and the capacity retention rate is 91.2% after 50 cycles at 1C rate.

The final test results of the above-mentioned three embodiments and comparative examples are shown in the following table:

The discharge cycle curves of Example 1 and Comparative Example 1 at a rate of 1C at a voltage of 2.75V to 4.3V are shown in Figure 1. It can be seen that Example 1 is co-coated with cobalt-boron cathode material compared to Comparative Example 1 without coating The capacity retention rate of the battery prepared with the positive electrode material is significantly improved.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (8)

1. A preparation method of a Y/La-doped Co/B Co-coated nickel-cobalt-manganese ternary positive electrode material is characterized by comprising the following steps:

step S1, weighing a nickel-cobalt-manganese precursor;

s2, weighing a certain amount of Y and La-containing compound and a certain amount of lithium source compound according to the expected proportion of the metal content of nickel, cobalt and manganese in the nickel-cobalt-manganese precursor;

step S3, adding the compound containing Y and La, the nickel-cobalt-manganese precursor and the lithium source compound into a high-speed mixer together for full mixing, and then calcining to obtain a doped base material;

step S4, adding the doped base material into deionized water, uniformly stirring, then dropwise adding cobalt salt, and continuously stirring to obtain cobalt hydroxide coated anode material slurry;

step S5, filtering, washing and drying the positive electrode material slurry to obtain positive electrode material powder coated by cobalt hydroxide;

step S6, mixing the cobalt hydroxide-coated positive electrode material powder with a lithium salt and carrying out secondary sintering to obtain a lithium cobaltate-coated positive electrode material;

and step S7, adding the B-containing compound and the lithium cobaltate-coated positive electrode material into a high-speed mixer for fully mixing, and then calcining to obtain the Y/La-doped Co/B Co-coated nickel-cobalt-manganese ternary positive electrode material.

2. The method for preparing the Y/La-doped Co/B-coated nickel-cobalt-manganese ternary cathode material of claim 1, wherein in step S2, the total molar amount of Y, La doped with the Y/La-doped Co/B-doped nickel-cobalt-manganese ternary cathode material is 0.001-0.1% of the total molar amount of nickel, cobalt and manganese metals in the nickel-cobalt-manganese precursor, the Y and La-containing compound is one or more of an oxide, a carbonate and a nitrate of Y, La, and the amount of the lithium source compound is calculated according to the molar ratio of Li: me =0.9-1.1:1, wherein Me is the total mole amount of nickel, cobalt and manganese in the nickel-cobalt-manganese precursor.

3. The method for preparing the Y/La-doped Co/B Co-coated nickel-cobalt-manganese ternary cathode material as claimed in claim 2, wherein the calcination temperature in the calcination process of the step S3 is 700 ℃ -900 ℃, and the calcination time is 10-25 h.

4. The method as claimed in claim 3, wherein the cobalt salt added dropwise in step S4 is one or more of cobalt sulfate, cobalt acetate, cobalt oxalate, cobalt nitrate, and cobalt chloride, and the amount of the cobalt coated is 1000-5000 ppm.

5. The method for preparing the Y/La-doped Co/B Co-coated nickel-cobalt-manganese ternary cathode material as claimed in claim 4, wherein the sintering temperature in the sintering process of the step S6 is 600-800 ℃, and the sintering time is 6-12 h.

6. The method as claimed in claim 5, wherein in step S7, the B source compound is one or two of boron-containing oxide and boric acid, and the amount of B element is 1000-3000 ppm.

7. The method for preparing the Y/La-doped Co/B Co-coated nickel-cobalt-manganese ternary cathode material as claimed in claim 6, wherein the calcination temperature in the calcination process of the step S7 is 200-400 ℃, and the calcination time is 6-12 h.

8. The Y/La-doped Co/B Co-coated nickel-cobalt-manganese ternary cathode material is characterized in that an inner layer is a Y-and La-doped base material, an outer layer is a Co-coated layer of Co and B, and the Y/La-doped Co/B Co-coated nickel-cobalt-manganese ternary cathode material is prepared by the method of any one of claims 1 to 7.

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