CN111092200A - Li3Cr(MoO4)3Coating modified high-nickel ternary cathode material and preparation method thereof - Google Patents
Li3Cr(MoO4)3Coating modified high-nickel ternary cathode material and preparation method thereof Download PDFInfo
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Abstract
Li3Cr(MoO4)3Coating modified high-nickel ternary cathode material and preparation method thereof, and Li3Cr(MoO4)3The base material coated by the coating modified high-nickel ternary cathode material is LiNi1‑x‑ yCoxMnyO2Wherein x is more than 0 and less than or equal to 0.20, y is more than 0 and less than or equal to 0.20, and the particles are micron-sized spherical particles with the particle size of less than 18 microns, and the base materialThe surface of the coating layer is coated with a fast ion conductor, and the coating layer is made of 100 nm-600 nm Li3Cr(MoO4)3Micro-nano particles. The preparation method comprises the steps of synthesizing a base material by a high-temperature solid phase method, washing and drying the base material, then sintering for the second time, coating and sintering. The positive electrode material has good material processability and high-temperature stability, and a lithium ion battery assembled by the electrode prepared from the positive electrode material has high specific capacity, and good rate capability, cycle performance and high-temperature safety performance; the method has the advantages of low reaction temperature, easy operation, easy control of the reaction process and suitability for large-scale mass production.
Description
Technical Field
The invention belongs to the technical field of lithium ion battery anode materials, and particularly relates to a coated modified high-nickel ternary anode material and a preparation method thereof.
Background
High nickel ternary positive electrode material (LiNi)1-x-yCoxMnyO2X is more than 0 and less than or equal to 0.2, y is more than 0 and less than or equal to 0.2) and a traditional ternary positive electrode material (LiNi)1-x-yCoxMnyO20 < 1-x-y < 0.5), high energy density, high working voltage, low cost, etc. However, due to the similar radiuses of Li and Ni ions, the mixed arrangement of Li and Ni is easily caused, and the problems of poor rate capability, low first coulombic efficiency, fast cycle attenuation and the like exist in the use process. And residual lithium can be generated on the surface of the material due to the reaction with air in the sintering process of the high-nickel ternary positive electrode material, so that the surface alkalinity of the material is high, the processing performance of the pole piece is poor on one hand, and the safety performance of the battery is poor due to the side reaction of the residual lithium and electrolyte on the other hand. In order to solve the problems, doping or cladding is generally adopted in the industry.
CN107565128A discloses a Li3Cr(MoO4)3The application of the Li in the anode of the lithium ion battery adopts a solid phase method and a sol-gel method to prepare the Li3Cr(MoO4)3And the lithium ion battery anode material is directly applied to a lithium ion battery as an anode material. The positive electrode material prepared by the methodThe material specific capacity reaches 250mAh/g, but in the actual working voltage range of 3.0-4.3V, the charging specific capacity is 80mAh/g, the discharging specific capacity is only 25mAh/g, and the requirements of the current market on the performance of the lithium ion battery can not be met.
Disclosure of Invention
The technical problem to be solved by the present invention is to overcome the above defects of the prior art and to provide a Li3Cr(MoO4)3A coating modified high-nickel ternary cathode material and a preparation method thereof. The method solves the technical problems of lithium-nickel mixed discharge and high surface residual alkali of the high-nickel ternary cathode material. The lithium ion battery assembled by the electrode prepared by the anode material has better rate performance, cycle performance and safety performance.
The technical scheme adopted by the invention for solving the technical problems is as follows: li3Cr(MoO4)3Coating modified high-nickel ternary cathode material, wherein the coated substrate is LiNi1-x-yCoxMnyO2(x is more than 0 and less than or equal to 0.20, y is more than 0 and less than or equal to 0.20) and is micron-sized spherical particles with the particle size of less than 18 microns, and the surface of the base material is coated with a fast ion conductor Li3Cr(MoO4)3The coating layer of (2) is composed of 100nm to 600nm of Li3Cr(MoO4)3Micro-nano particles.
Preferably, the coating layer Li3Cr(MoO4)3Relative to the number of moles of the substrate LiNi1-x-yCoxMnyO2Is n, 0<n<0.03。
Li of the invention3Cr(MoO4)3The preparation method of the coating modified high-nickel ternary positive electrode comprises the following steps:
(1) mechanically mixing a nickel-cobalt-manganese hydroxide precursor and lithium hydroxide, sintering in an oxygen atmosphere, cooling to room temperature in the oxygen atmosphere, crushing by using a pair of rollers, and sieving to obtain a base material;
(2) putting the base material in the step (1) into deionized water, continuously stirring for washing, centrifuging, drying and sieving to obtain a washing and drying product;
(3) carrying out secondary sintering on the water-washed and dried product obtained in the step (2) in an oxygen atmosphere, cooling to room temperature in the oxygen atmosphere, crushing and sieving;
(4) LiOH, Cr (NO)3)3、(NH4)6Mo7O24Adding the mixture into deionized water for dissolving in several times to obtain a coating solution, keeping the temperature constant during the dissolving period, and continuously stirring;
(5) dispersing the product obtained in the step (3) into the coating liquid obtained in the step (4), and stirring at constant speed and constant temperature until the mixture is in a powder state;
(6) and (5) sintering the powder mixture obtained in the step (5) in an oxygen atmosphere, cooling to room temperature in the oxygen atmosphere, crushing, and sieving to obtain the powder mixture.
Preferably, in the step (1), the ratio of the total number of atoms of nickel, cobalt and manganese elements of the nickel, cobalt and manganese hydroxide precursor and the lithium hydroxide to the number of atoms of lithium is 1: 1.2-1.5, and lithium is volatile at high temperature, so that the stoichiometry of lithium hydroxide is properly increased, and the ratio of the number of atoms actually participating in chemical reaction is ensured to be substantially consistent with that of a target product.
Preferably, in the step (1), the mechanical mixing is performed in a high-speed mixer.
Preferably, in the step (1), the oxygen atmosphere has an oxygen concentration of 99% or more.
Preferably, in the step (1), in order to form an oxygen atmosphere, oxygen needs to be introduced into the reactor, and the flow rate of the oxygen is 1-5 Nm3(more preferably 2 to 4 Nm)3/h)。
Preferably, in the step (1), the sintering temperature is 500-900 ℃ (more preferably 650-850 ℃, and most preferably 750-800 ℃).
Preferably, in the step (1), the sintering time is 8-15 h (more preferably 9-13 h, and most preferably 10-12 h).
Preferably, in the step (1), the sieving mesh number is 200-400 meshes.
The water-material ratio refers to the mass ratio of the deionized water to the base material. Preferably, in the step (2), the water-material ratio in the water washing is 1.0-3.0: 1 (more preferably 1.5-2.0: 1).
Preferably, in the step (2), the washing time is 20-60 min (more preferably 30-45 min).
Preferably, in the step (2), the drying temperature is 80-150 ℃ (more preferably 100-120 ℃), and the drying time is 16-18 h.
Preferably, in the step (2), the mesh number of the sieve is 200-400 meshes.
Preferably, in the step (3), the temperature of the secondary sintering is 400 to 800 ℃ (more preferably 500 to 700 ℃, and further preferably 550 to 650 ℃).
Preferably, in the step (3), the sintering time is 5-10 h (more preferably 6-8 h).
Preferably, in the step (3), the oxygen atmosphere has an oxygen concentration of not less than 99%.
Preferably, in the step (3), in order to form an oxygen atmosphere, oxygen needs to be introduced into the reactor, and the flow rate of the oxygen is 1-5 Nm3(more preferably 2 to 3 Nm)3/h)。
Preferably, in the step (3), the mesh number of the sieve is 200-400 meshes.
Preferably, in the step (4), the LiOH, Cr (NO) are3)3、(NH4)6Mo7O24The addition amount of (A) is 3-4: 1 corresponding to the atomic number ratio of Li to Cr; li and Mo are 1-2: 1; lithium is volatilized under high temperature conditions, and thus the lithium source is excessively added.
Preferably, in the step (4), the temperature of the constant-temperature stirring is 60 to 90 ℃ (more preferably 70 to 80 ℃).
Preferably, in the step (5), the water content of the mixture is less than or equal to 1 percent.
Preferably, in the step (6), the oxygen atmosphere has an oxygen concentration of 99% or more.
Preferably, in the step (6), in order to form an oxygen atmosphere, oxygen needs to be introduced into the reactor, and the flow rate of the oxygen is 1-3 Nm3/h。
Preferably, in the step (6), the sintering temperature is 400 to 700 ℃ (more preferably 500 to 600 ℃).
Preferably, in the step (6), the sintering time is 3-8 h (more preferably 4-7 h).
Preferably, in the step (6), the mesh number of the sieve is 200-400 meshes.
Firstly, synthesizing a high-nickel ternary positive electrode material by using a high-temperature solid phase method, washing and drying the positive electrode material, then carrying out secondary sintering, and pre-reacting lithium hydroxide, chromic nitrate and ammonium molybdate to generate Li3Cr(MoO4)3The uniform coating liquid is prepared by preparing Li on the anode material after secondary sintering in a motion state of continuous constant-temperature stirring3Cr(MoO4)3And finally sintering to obtain the material.
Li3Cr(MoO4)3The lithium ion battery cathode material belongs to polyanion cathode materials, has narrow energy band and high electronic conductivity, and can effectively improve the lithium ion transmission efficiency and improve the specific capacity and the rate capability of the cathode after being coated on the surface of a high-nickel ternary cathode material.
The washing, drying and secondary sintering can remove residual alkali on the surface of the high-nickel ternary material, reduce the side reaction of the material and electrolyte, and improve the processing performance and safety performance of the material.
The reaction temperature of the coating is low, and the coating is easy to operate; the obtained material has good uniformity and consistency by continuous constant-temperature stirring in the coating process, and the multiplying power performance and the cycle performance of the material are effectively improved.
Compared with the prior art, the invention has the following beneficial effects:
(1) the invention uses water washing, secondary sintering and Li coating3Cr(MoO4)3The alkali content on the surface of the material is reduced, the side reaction with the electrolyte is reduced, and the safety performance, the material processing performance and the high-temperature stability of the high-nickel ternary cathode material are improved;
(2) the invention coats Li on the surface of the material3Cr(MoO4)3The surface activity and the conductive efficiency of the material are improved, and the lithium ion transmission efficiency is accelerated, so thatThe rate capability and the cycle performance of the electrode made of the material are improved;
(3) the obtained material coating layer is uniform and consistent through continuous stirring and dynamic coating;
(4) the lithium ion battery assembled by the electrode prepared by the high-nickel ternary cathode material has high specific capacity, and good rate capability, cycle performance and high-temperature safety performance;
(5) the method has the advantages of low reaction temperature, easy operation, easy control of the reaction process and suitability for large-scale mass production.
Drawings
FIG. 1 shows Li prepared in example 1 of the present invention3Cr(MoO4)3SEM image of 5000 times magnification of the coating modified high nickel ternary cathode material;
FIG. 2 shows Li prepared in example 1 of the present invention3Cr(MoO4)3SEM image of 10000 times magnification of coating modified high nickel ternary positive electrode material;
FIG. 3 is a comparison graph of capacity retention ratio curves of button cells assembled by electrodes made of the materials obtained in examples 1 to 3 of the present invention and comparative example within a voltage range of 3.0 to 4.3V for 100 weeks at 2C cycle;
fig. 4 is a comparison graph of multiplying power curves of button cells assembled by electrodes made of the materials obtained in examples 1 to 3 of the invention and comparative examples, wherein the multiplying power curves are 0.1C, 0.5C, 1C, 2C, 5C and 10C.
Detailed Description
For a better understanding of the present invention, reference is made to the following detailed description and accompanying drawings. It should be understood that the examples are for further illustration of the invention and are not intended to limit the scope of the invention. Moreover, it should be understood that the invention is not limited to the above-described embodiments, but is capable of various modifications and changes within the scope of the invention.
The following examples and comparative examples all used commercially available starting materials.
The preparation method of the lithium ion battery is not particularly limited, and the technical scheme familiar to the technical personnel in the field can be adopted.
Example 1
(1) Mixing 811 Ni-Co-Mn hydroxide precursor and lithium hydroxide according to the ratio of the total number of atoms of Ni, Co and Mn to the number of atoms of Li of 1:1.3, uniformly mixing in a high-speed mixer, and making the flow rate of the bottom gas with oxygen concentration of more than or equal to 99% be 2Nm3Calcining for 12h at 770 ℃ under the protection of oxygen atmosphere, cooling to room temperature, rolling, crushing, and sieving by a 320-mesh sieve to obtain a base material;
(2) putting the base material into deionized water according to the water-material ratio of 1.5:1, washing for 30min, centrifugally drying, drying in a vacuum oven for 18h at the drying temperature of 120 ℃, and sieving by a 320-mesh sieve to obtain a dried material;
(3) the air flow of the dried material at the bottom with the oxygen concentration of more than or equal to 99 percent is 1Nm3Sintering for 6h at 550 ℃ in an oxygen atmosphere, cooling to room temperature, and sieving by a 320-mesh sieve to obtain a secondary sintering material;
(4) LiOH, Cr (NO)3)3、(NH4)6Mo7O24Adding the powder into deionized water, uniformly stirring, and adding the secondary sintering material; wherein the addition of LiOH accounts for 0.24 percent of the mass of the secondary sintering material, and Cr (NO)3)3The adding amount is 0.795 percent of the mass of the secondary sintering material, (NH)4)6Mo7O24The adding amount is 1.666 percent of the mass of the secondary sintering material; then continuously stirring at a constant temperature of 80 ℃ in an electric heating jacket for coating until the mixture is converted into a mixture with the water content less than or equal to 1 percent, thus obtaining a coating material;
(5) the flow rate of the coating material in the bottom with the oxygen concentration of more than or equal to 99 percent is 1Nm3Calcining for 6h at 500 ℃ in oxygen atmosphere, cooling to room temperature, and sieving with a 300-mesh sieve to obtain Li3Cr(MoO4)3And coating the modified high-nickel ternary cathode material.
Scanning electron microscope was used to measure Li prepared in example 13Cr(MoO4)3The coated modified high-nickel ternary cathode material is analyzed, as shown in fig. 1 and 2, the obtained material is micron-sized spherical particles with the particle size of less than 15 microns, and the surface of the micron-sized spherical particles is coated by micro-nano particles with the particle size of 100 nm-500 nm.
Example 2
(1) Mixing 811 Ni-Co-Mn hydroxide precursor and lithium hydroxide according to the ratio of the total number of atoms of Ni, Co and Mn to the number of atoms of Li of 1:1.5, uniformly mixing in a high-speed mixer, and making the flow rate of bottom gas with oxygen concentration of more than or equal to 99% be 4Nm3Calcining for 10h at 800 ℃ under the protection of oxygen atmosphere, cooling to room temperature, and then performing roller pair crushing and 350-mesh sieving to obtain a base material;
(2) putting the base material into deionized water according to the water-material ratio of 1.7:1, washing for 45min, centrifugally drying, drying in a vacuum oven for 16h at the drying temperature of 130 ℃, and sieving by 350 meshes to obtain a dried material;
(3) the air flow of the dried material at the bottom with the oxygen concentration of more than or equal to 99 percent is 2Nm3Calcining for 8 hours at 650 ℃ in an oxygen atmosphere, cooling to room temperature, and sieving by a 350-mesh sieve to obtain a secondary sintering material;
(4) LiOH, Cr (NO)3)3、(NH4)6Mo7O24Adding the powder into deionized water, uniformly stirring, and adding the secondary sintering material; wherein the addition of LiOH accounts for 0.115 percent of the mass of the secondary sintering material, and Cr (NO)3)3The addition amount of (NH) is 0.364 percent of the mass of the secondary sintering material4)6Mo7O24The adding amount is 0.763 percent of the mass of the secondary sintering material; then continuously stirring at a constant temperature of 70 ℃ in an electric heating jacket for coating until the mixture is converted into a mixture with the water content less than or equal to 1 percent, thus obtaining a coating material;
(5) the flow rate of the coating material in the bottom with the oxygen concentration of more than or equal to 99 percent is 3Nm3Calcining for 7h at 550 ℃ in oxygen atmosphere, cooling to room temperature, and sieving with a 340-mesh sieve to obtain Li3Cr(MoO4)3And coating the modified high-nickel ternary cathode material.
Scanning electron microscope was used for the Li prepared in example 23Cr(MoO4)3The coating modified high-nickel ternary positive electrode material is analyzed, the obtained material is micron-sized spherical particles with the particle size of less than 12 microns, and the surface of the material is coated by micro-nano particles with the particle size of 100 nm-400 nm.
Example 3
(1) Will be provided withMixing 811 Ni-Co-Mn hydroxide precursor and lithium hydroxide according to the ratio of the total number of atoms of Ni, Co and Mn to the number of atoms of Li of 1:1.2, uniformly mixing in a high-speed mixer, and controlling the flow rate of bottom gas with oxygen concentration of more than or equal to 99% to be 3Nm3Calcining for 11h at 750 ℃ under the protection of oxygen atmosphere, cooling to room temperature, and then rolling, crushing and sieving by a 280-mesh sieve to obtain a base material;
(2) putting the base material into deionized water according to the water-material ratio of 2:1, washing for 35min, then centrifugally drying, putting into a vacuum oven for drying for 18h at the drying temperature of 100 ℃, and then sieving by 280 meshes to obtain a dried material;
(3) the air flow of the dried material at the bottom with the oxygen concentration of more than or equal to 99 percent is 3Nm3Calcining for 6 hours at 600 ℃ in an oxygen atmosphere, cooling to room temperature, and sieving by a 280-mesh sieve to obtain a secondary sintering material;
(4) LiOH, Cr (NO)3)3、(NH4)6Mo7O24Adding the powder into deionized water, uniformly stirring, and adding the secondary sintering material; wherein the addition of LiOH accounts for 0.704 percent of the mass of the secondary sintering material, and Cr (NO)3)3The addition amount of (NH) is 2.23 percent of the mass of the secondary sintering material4)6Mo7O24The adding amount is 4.673 percent of the mass of the secondary sintering material; then continuously stirring at a constant temperature of 75 ℃ in an electric heating jacket for coating until the mixture is converted into a mixture with the water content less than or equal to 1 percent, thus obtaining a coating material;
(5) the flow rate of the coating material in the bottom with the oxygen concentration of more than or equal to 99 percent is 2Nm3Calcining for 4h at 600 ℃ in oxygen atmosphere, cooling to room temperature, and sieving with 330 meshes to obtain Li3Cr(MoO4)3And coating the modified high-nickel ternary cathode material.
Scanning electron microscope was used for Li prepared in example 33Cr(MoO4)3The coating modified high-nickel ternary positive electrode material is analyzed, the obtained material is micron-sized spherical particles with the particle size of less than 18 microns, and the surface of the material is coated by micro-nano particles with the particle size of 200 nm-600 nm.
Comparative example
Mixing a 811 nickel-cobalt-manganese hydroxide precursor and lithium hydroxide according to the proportion that the total number of atoms of nickel, cobalt and manganese and the atomic ratio of lithium are 1:1.3, uniformly mixing in a high-speed mixer, calcining for 18h at 770 ℃ under the protection of oxygen atmosphere, cooling to room temperature, and then carrying out roller pair, crushing and screening for 250 meshes to obtain the high-nickel ternary cathode material.
The surface residual alkali content and the pH value of the materials obtained in examples 1 to 3 and comparative example were measured, respectively, and the results are shown in Table 1.
Assembling the battery: the materials obtained in examples 1-3 and comparative example are respectively made into electrodes and assembled into button cells by adopting the technical scheme well known by the technicians in the field. The specific method comprises the following steps: adding polyvinylidene fluoride into N-methyl pyrrolidone (NMP), stirring at a high speed for 2h, adding a positive electrode material and acetylene black which are weighed according to the mass ratio of 96:2 (the mass ratio of polyvinylidene fluoride to the positive electrode material is 2:96), dispersing at a high speed for 0.5h to form viscous slurry, uniformly coating the viscous slurry on an aluminum foil, then carrying out vacuum baking at 120 ℃, tabletting, and cutting a positive plate with the diameter of 14 mm. Taking a pure lithium sheet with the diameter of 18mm as a negative electrode sheet and 1mol/L LiPF6And the button cell is assembled by taking the mixed solution of + DEC/EC as electrolyte and a poly Celgard propylene microporous membrane as a diaphragm in a glove box filled with argon.
And (3) testing electrical properties: adopting an LAND battery test system, respectively testing the initial discharge specific capacity and the button cell cycle curve of the button cell assembled by the electrodes prepared from the materials obtained in the examples 1-3 and the comparative example in a voltage range of 3.0-4.3V at a constant temperature of 25 ℃ under a 2C charging and discharging condition, and comparing the obtained capacity retention rate curve with a graph shown in figure 3; and (3) respectively carrying out charging and discharging on the button cell under the conditions of 0.1C, 0.5C, 1C, 2C, 5C and 10C, testing a multiplying power curve of the button cell, and comparing the obtained multiplying power curve with a graph shown in figure 4, wherein specific data are shown in table 2.
The test results of part of key physicochemical and electrical properties of the materials obtained in examples 1-3 and comparative example are shown in Table 1.
Table 1 results of physical, chemical and electrical property tests of the high nickel ternary positive electrode materials prepared in examples 1 to 3 and comparative examples;
table 2 rate performance results for the high nickel ternary cathode materials prepared in examples 1-3 and comparative examples.
As can be seen from Table 1, compared with the high-nickel ternary cathode material prepared by the conventional method, Li provided in embodiments 1 to 3 of the present invention3Cr(MoO4)3The surface residual alkali content of the coated modified high-nickel ternary positive electrode material is obviously reduced, and the specific capacity, the first coulombic efficiency and the cycle performance of the prepared battery are also obviously improved because of Li3Cr(MoO4)3The material has narrow energy band, high conductivity and fast ion transmission channel, and can effectively improve the electrochemical performance of the material.
As can be seen from Table 2, compared with the high-nickel ternary cathode material prepared by the conventional method, Li provided in embodiments 1 to 3 of the present invention3Cr(MoO4)3The rate capability of the coating modified high-nickel anode ternary material is obviously improved, and the coating modified high-nickel anode ternary material has obvious advantages especially under large discharge rate.
The above description is not intended to limit the invention, nor is the invention limited to the above examples. Those skilled in the art should also realize that changes, modifications, additions and substitutions can be made without departing from the spirit of the invention.
Claims (10)
1. Li3Cr(MoO4)3The coating modified high-nickel ternary cathode material is characterized in that the coated base material is LiNi1-x-yCoxMnyO2Wherein x is more than 0 and less than or equal to 0.20, y is more than 0 and less than or equal to 0.20, the material is micron-sized spherical particles with the particle size of less than 18 microns, and the surface of the base material is coated with a fast ion conductor Li3Cr(MoO4)3The coating layer (a) of (b),from 100nm to 600nm of Li3Cr(MoO4)3Micro-nano particles.
2. Li according to claim 13Cr(MoO4)3The coating modified high-nickel ternary cathode material is characterized in that the coating layer Li3Cr(MoO4)3Relative to the number of moles of the substrate LiNi1-x-yCoxMnyO2Is n, 0<n<0.03。
3. Li3Cr(MoO4)3The preparation method of the coating modified high-nickel ternary cathode material is characterized by comprising the following steps of:
(1) mechanically mixing a nickel-cobalt-manganese hydroxide precursor and lithium hydroxide, sintering in an oxygen atmosphere, cooling to room temperature in the oxygen atmosphere, crushing by using a pair of rollers, and sieving to obtain a base material;
(2) putting the base material in the step (1) into deionized water, continuously stirring for washing, centrifuging, drying and sieving to obtain a washing and drying product;
(3) carrying out secondary sintering on the water-washed and dried product obtained in the step (2) in an oxygen atmosphere, cooling to room temperature in the oxygen atmosphere, crushing and sieving;
(4) LiOH, Cr (NO)3)3、(NH4)6Mo7O24Adding the mixture into deionized water for dissolving in several times to obtain a coating solution, keeping the temperature constant during the dissolving period, and continuously stirring;
(5) dispersing the product obtained in the step (3) into the coating liquid obtained in the step (4), and stirring at constant speed and constant temperature until the mixture is in a powder state;
(6) and (5) sintering the powder mixture obtained in the step (5) in an oxygen atmosphere, cooling to room temperature in the oxygen atmosphere, crushing, and sieving to obtain the powder.
4. Li according to claim 33Cr(MoO4)3Coating modified polymerThe preparation method of the nickel ternary cathode material is characterized by comprising the following steps: in the step (1), the ratio of the total number of atoms of nickel, cobalt and manganese elements of the nickel, cobalt and manganese hydroxide precursor and the lithium hydroxide to the number of lithium atoms is 1: 1.2-1.5.
5. Li as claimed in claim 3 or 43Cr(MoO4)3The preparation method of the coating modified high-nickel ternary cathode material is characterized by comprising the following steps of: in the step (1), the mechanical mixing is carried out in a high-speed mixer; the oxygen atmosphere has an oxygen concentration of more than or equal to 99 percent; in order to form an oxygen atmosphere, oxygen needs to be introduced into the reactor, and the flow rate of the oxygen is 1-5 Nm3Preferably 2 to 4Nm3H; the sintering temperature is 500-900 ℃, preferably 650-850 ℃, and more preferably 750-800 ℃; the sintering time is 8-15 h, preferably 9-13 h, more preferably 10-12 h, and the sieving mesh number is 200-400 meshes.
6. Li according to any one of claims 3 to 53Cr(MoO4)3The preparation method of the coating modified high-nickel ternary cathode material is characterized by comprising the following steps of: in the step (2), during the water washing, the mass ratio of the deionized water to the base material is 1.0-3.0: 1, and preferably 1.5-2.0: 1; the washing time is 20-60 min, preferably 30-45 min; the drying temperature is 80-150 ℃, the preferable drying temperature is 100-120 ℃, the drying time is 16-18 h, and the sieving mesh number is 200-400 meshes.
7. Li according to any one of claims 3 to 63Cr(MoO4)3The preparation method of the coating modified high-nickel ternary cathode material is characterized by comprising the following steps of: in the step (3), the temperature of the secondary sintering is 400-800 ℃, preferably 500-700 ℃, and more preferably 550-650 ℃; the sintering time is 5-10 hours, preferably 6-8 hours; the oxygen atmosphere has an oxygen concentration of more than or equal to 99 percent; in order to form an oxygen atmosphere, oxygen needs to be introduced into the reactor, and the flow rate of the oxygen is 1-5 Nm3Preferably 2 to 3 Nm/h3The screening mesh number is 200-400 meshes.
8. Li according to any one of claims 3 to 73Cr(MoO4)3The preparation method of the coating modified high-nickel ternary cathode material is characterized by comprising the following steps of: in the step (4), the LiOH and Cr (NO) are added3)3、(NH4)6Mo7O24The addition amount of (A) is in accordance with atomic number ratio of Li: Cr = 3-4: 1, Li: Mo = 1-2: 1; the constant-temperature stirring temperature is 60-90 ℃, and preferably 70-80 ℃.
9. Li according to any one of claims 3 to 83Cr(MoO4)3The preparation method of the coating modified high-nickel ternary cathode material is characterized by comprising the following steps of: in the step (5), the water content of the mixture is less than or equal to 1%.
10. Li according to any one of claims 3 to 93Cr(MoO4)3The preparation method of the coating modified high-nickel ternary cathode material is characterized by comprising the following steps of: in the step (6), the oxygen atmosphere has an oxygen concentration of more than or equal to 99%; in order to form an oxygen atmosphere, oxygen needs to be introduced into the reactor, and the flow of the oxygen is 1-3 Nm3H; the sintering temperature is 400-700 ℃, and preferably 500-600 ℃; the sintering time is 3-8 hours, preferably 4-7 hours, and the sieving mesh number is 200-400 meshes.
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