A doped coated high-rate lithium manganate cathode material and a preparation method thereof

Abstract

The present application relates to the technical field of lithium battery, in particular to a kind of doped coating type high rate lithium manganate positive electrode material and preparation method thereof, for solving the problems of poor rate performance and low capacity retention rate of existing lithium manganate positive electrode material;The lithium manganate positive electrode material includes fluoropyrrole thiophene group COF coated zirconium ruthenium co-doped lithium manganate, acetylene carbon black, polyvinylidene fluoride and N-methylpyrrolidone;The preparation method first prepares zirconium ruthenium co-doped lithium manganate, zirconium and ruthenium are doped in the process of preparing lithium manganate, respectively synthesized third intermediate product containing amino fluoropyrrole and thiophene containing aldehyde group, and fluoropyrrole thiophene group COF is synthesized on the surface of zirconium ruthenium co-doped lithium manganate, to form core-shell composite material, so that good capacity and efficiency can be maintained under high rate charge and discharge.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, specifically to a doped and coated high-rate lithium manganese oxide cathode material and its preparation method. Background Technology

[0002] In the field of lithium-ion batteries, the cathode material is one of the key factors determining battery performance. Lithium manganese oxide (LiMCO) has attracted widespread attention due to its low cost, environmental friendliness, and high energy density. However, traditional LiMCO cathode materials suffer from low capacity retention and poor rate performance during charge and discharge, limiting their practical application in high-power applications. Therefore, this invention provides a doped and coated high-rate LiMCO cathode material and its preparation method, improving the rate performance and capacity retention of LiMCO cathode materials. Summary of the Invention

[0003] In order to overcome the above-mentioned technical problems, the present invention aims to provide a doped and coated high-rate lithium manganese oxide cathode material and its preparation method, which solves the problems of poor rate performance and low capacity retention of existing lithium manganese oxide cathode materials.

[0004] The objective of this invention can be achieved through the following technical solutions: In a first aspect, this application provides a method for preparing a doped and coated high-rate lithium manganese oxide cathode material, comprising the following steps: Step 1: Weigh out 50-100 parts of fluoropyrrolethiophene-based COF-coated zirconium-ruthenium co-doped lithium manganese oxide, 10-20 parts of acetylene black, and 6-12 parts of polyvinylidene fluoride according to the weight ratio, and set aside; wherein, the polyvinylidene fluoride is of type PVDF5130. Step 2: The fluoropyrrolethiophene-based COF-coated zirconium-ruthenium co-doped lithium manganese oxide, acetylene black, and polyvinylidene fluoride were ground. Then, N-methylpyrrolidone was added to adjust the solid content to 45%-55% and the mixture was magnetically stirred for 3 hours. The mixture was then coated onto carbon-coated aluminum foil using a coating machine and placed in a drying oven for vacuum drying at 70°C for 12 hours. Finally, the mixture was stamped into a circular electrode using a slicing machine to obtain the doped and coated high-rate lithium manganese oxide cathode material.

[0005] The fluoropyrrolethiophene-based COF-coated zirconium-ruthenium co-doped lithium manganese oxide is prepared by the following steps: Step A1: Add manganese tetroxide, lithium carbonate, zirconium dioxide, and ruthenium dioxide to a ball mill jar. The mass ratio of raw materials to milling beads is 1:10. Add anhydrous ethanol and ball mill at 400 r / min for 4 h. After drying, grind and sieve through a 200 mesh sieve. Place the sieve in a crucible and put it in a muffle furnace. Heat the sieve to 450 °C at a heating rate of 6 °C / min and hold for 2 h. Then heat the sieve to 800 °C and hold for 10 h. Cool and grind the sieve through a 200 mesh sieve to obtain zirconium-ruthenium co-doped lithium manganese oxide. Step A2: Add 3,5-difluoro-4-hydroxybenzonitrile, 1-bromohexane and potassium carbonate to a three-necked flask equipped with a thermometer and a stirrer, purge with nitrogen, add butanone and stir for 10-20 min, heat to 80℃ and stir for 36-48 h, cool and filter, concentrate the filtrate by rotary evaporation, add to ethyl acetate, wash 3-5 times with saturated sodium chloride solution, dry with anhydrous magnesium sulfate, and purify by silica gel column chromatography with petroleum ether-ethyl acetate mixed solvent to obtain hexyl difluorobenzonitrile;

[0006] Step A3: Add sodium and ferric chloride to a three-necked flask equipped with a thermometer and a stirrer, purge with nitrogen, add isoamyl alcohol and reflux for 6-8 hours, add hexyl difluorobenzonitrile, add diisopropyl succinate using a peristaltic pump, controlling the addition time to 2 hours, cool, add to a methanol-formic acid mixed solution, filter, wash with hot methanol until the filtrate is clear, dry, and obtain the first intermediate product;

[0007] Step A4: Add phosphorus oxychloride, the first intermediate, 2-acetonitrile-5-nitropyridine, and tetrahydrofuran to a four-necked flask equipped with a thermometer, stirrer, and reflux condenser. Purge with nitrogen, stir for 10-20 min, reflux for 12-15 h, remove tetrahydrofuran and phosphorus oxychloride by vacuum distillation, add to dichloromethane, wash with sodium bicarbonate solution to adjust pH to 7, separate the organic phase, dry with anhydrous magnesium sulfate, filter, concentrate, add to methanol to precipitate, filter, wash with methanol until the filtrate is clear, purify by silica gel column chromatography with n-hexane-ethyl acetate mixed solvent, dry, and obtain the second intermediate.

[0008] Step A5: Add reduced iron powder, ammonium chloride, and an aqueous ethanol solution to a three-necked flask equipped with a thermometer, stirrer, and reflux condenser. Reflux and stir. Dissolve the second intermediate product in dichloromethane and add it dropwise to the flask. React for 6 hours. Filter the iron powder with diatomaceous earth. Remove dichloromethane and ethanol by rotary evaporation. Filter, wash with hot water 5-7 times, wash with ethanol 2-4 times, and dry to obtain the third intermediate product.

[0009] Step A6: Add 1,3,5-tribromobenzene, tetrahydrofuran, tetra(triphenylphosphine)palladium, 2-aldehydethiophene-4-boronic acid, and potassium carbonate solution to a three-necked flask equipped with a stirrer and thermometer. Purge with argon gas and stir for 10-20 min. React at 90 °C for 6 h. Add to ice-saturated sodium chloride solution and extract with dichloromethane 3-5 times. Combine the organic phases and concentrate. Purify by silica gel column chromatography with a mixed solvent of hexane and ethyl acetate. Dry to obtain the fourth intermediate product.

[0010] Step A7: Add zirconium-ruthenium co-doped lithium manganese oxide and anhydrous ethanol to a single-necked flask equipped with a thermometer, sonicate for 20 min, add the third intermediate, the fourth intermediate, 1,4-dioxane and glacial acetic acid, freeze in a liquid nitrogen bath, evacuate, seal and react at 120°C for 72 h, collect the solid and wash it 5-7 times with N,N-dimethylformamide and tetrahydrofuran, filter by sedimentation, place in a drying oven and dry under vacuum at 100°C for 6 h to obtain fluoropyrrolethiophene-based COF-coated zirconium-ruthenium co-doped lithium manganese oxide.

[0011] As a further aspect of the present invention: the ratio of manganese tetroxide, lithium carbonate, zirconium dioxide, ruthenium dioxide and anhydrous ethanol used in step A1 is 0.066-0.132 mol: 0.0525-0.105 mol: 0.001-0.002 mol: 0.001-0.002 mol: 50-100 mL.

[0012] As a further aspect of the present invention: the ratio of the amounts of 3,5-difluoro-4-hydroxybenzonitrile, 1-bromohexane, potassium carbonate and butanone in step A2 is 0.05-0.1 mol: 0.055-0.11 mol: 0.2-0.4 mol: 300-600 mL.

[0013] As a further aspect of the present invention: the volume ratio of petroleum ether to ethyl acetate in the petroleum ether-ethyl acetate mixed solvent in step A2 is 8:1.

[0014] As a further aspect of the present invention: the ratio of sodium, ferric chloride, isoamyl alcohol, hexyl difluorobenzonitrile, and diisopropyl succinate in step A3 is 0.8-1.6 mol: 1-2 mmol: 300-600 mL: 0.1-0.2 mol: 86-172 mmol.

[0015] As a further aspect of the present invention: the volume ratio of methanol to formic acid in the methanol-formic acid mixed solution in step A3 is 45:1.

[0016] As a further aspect of the present invention: the ratio of phosphorus oxychloride, the first intermediate product, 2-acetonitrile-5-nitropyridine and tetrahydrofuran in step A4 is 40-80 mmol: 4-8 mmol: 10-20 mmol: 400-800 mL.

[0017] As a further aspect of the present invention: the volume ratio of n-hexane to ethyl acetate in the n-hexane-ethyl acetate mixed solvent in step A4 is 8:1.

[0018] As a further aspect of the present invention: the ratio of reduced iron powder, ammonium chloride, aqueous ethanol solution, second intermediate product and dichloromethane in step A5 is 200-400 mmol: 100-200 mmol: 480-960 mL: 25-50 mmol: 60-120 mL.

[0019] As a further aspect of the present invention: the volume ratio of ethanol to water in the ethanol-water solution described in step A5 is 3:1.

[0020] As a further aspect of the present invention: the ratio of the amounts of 1,3,5-tribromobenzene, tetrahydrofuran, tetra(triphenylphosphine)palladium, 2-aldehydethiophene-4-boronic acid and potassium carbonate solution in step A6 is 10-20 mmol: 60-120 mL: 0.3-0.6 mmol: 30-60 mmol: 15-30 mL.

[0021] As a further aspect of the present invention: the molar concentration of the potassium carbonate solution in step A6 is 1 mol / L.

[0022] As a further aspect of the present invention: the volume ratio of n-hexane to ethyl acetate in the n-hexane-ethyl acetate mixed solvent in step A6 is 3:1.

[0023] As a further embodiment of the present invention: the ratio of zirconium-ruthenium co-doped lithium manganese oxide, anhydrous ethanol, third intermediate product, fourth intermediate product, 1,4-dioxane and glacial acetic acid used in step A7 is 1-2g: 20-40mL: 0.45-0.9mmol: 0.68-1.36mmol: 0.5-1mL: 0.75-1.5mL.

[0024] As a further aspect of the present invention: the molar concentration of glacial acetic acid in step A7 is 6 mol / L.

[0025] Secondly, the present invention provides a doped and coated high-rate lithium manganese oxide cathode material, which is prepared according to the above-described preparation method.

[0026] The beneficial effects of this invention are: The present invention discloses a doped and coated high-rate lithium manganese oxide cathode material. During the synthesis of lithium manganese oxide, zirconium and ruthenium are doped to synthesize a third intermediate containing aminofluoropyrrole and a thiophene containing an aldehyde group. Fluoropyrrole-thiophene-based COF is synthesized on the surface of zirconium and ruthenium co-doped lithium manganese oxide to form a core-shell composite material. After multiple charge-discharge cycles, it can still maintain a high capacity retention rate and good charge-discharge performance.

[0027] A high-rate lithium manganese oxide cathode material with doping coating was prepared. First, zirconium-ruthenium co-doped lithium manganese oxide was prepared using manganese tetroxide, lithium carbonate, zirconium dioxide, and ruthenium dioxide. Ruthenium refines the particle structure and reduces the diffusion paths of lithium ions and electrons, while zirconium ions reduce the disorder of elemental arrangement, decrease particle size, and improve the rate and cycle performance of the cathode material. Hexyl difluorobenzonitrile was synthesized using 3,5-difluoro-4-hydroxybenzonitrile and 1-bromohexane. Hexyl difluorobenzonitrile was then reacted with isoamyl alcohol and diisopropyl succinate to synthesize a first intermediate containing an aldehyde pyrrole. This first intermediate was then reacted with 2-acetonitrile-5-nitropyridine to synthesize a second intermediate containing a nitro group. The nitro group in the second intermediate was reduced to obtain a third intermediate containing an amino group. Finally, 1,3,5-tribromobenzene was reacted with 2-aldehyde thiophene-4-... Boric acid is catalyzed by tetra(triphenylphosphine)palladium to generate a fourth intermediate containing aldehyde thiophene. The third and fourth intermediates react with amino groups and aldehyde groups on the surface of zirconium-ruthenium co-doped lithium manganese oxide to form a fluoropyrrolethiophene-based COF, resulting in a fluoropyrrolethiophene-based COF coating on zirconium-ruthenium co-doped lithium manganese oxide. The fluoropyrrolethiophene-based COF provides directional ion transport channels through its crystalline porous structure, reducing lithium-ion diffusion resistance and improving rate performance. Furthermore, the fluorine atoms, pyrrole rings, and thiophene units in the fluoropyrrolethiophene-based COF can introduce abundant redox sites, increasing lithium-ion storage sites and improving the capacity retention of the cathode material. The synergistic effect of the coating layer and the doping elements enables a lithium manganese oxide cathode material that can not only work stably under high rate conditions but also maintain high efficiency after long-term use. Attached Figure Description

[0028] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0029] Figure 1 This is a SEM image of fluoropyrrolethiophene-based COF-coated zirconium-ruthenium co-doped lithium manganese oxide in Example 3. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1: This embodiment describes a method for preparing a doped and coated high-rate lithium manganese oxide cathode material, including the following steps: Step A1: Add 0.066 mol manganese tetroxide, 0.0525 mol lithium carbonate, 0.001 mol zirconium dioxide, and 0.001 mol ruthenium dioxide to a ball mill jar. The mass ratio of raw materials to milling beads is 1:10. Add 50 mL of anhydrous ethanol and ball mill at 400 r / min for 4 h. After drying, grind the mixture and sieve it through a 200 mesh sieve. Place the mixture in a crucible in a muffle furnace and heat it to 450 °C at a heating rate of 6 °C / min. Hold the temperature for 2 h, then heat it to 800 °C and hold it for 10 h. Cool the mixture, grind it, and sieve it through a 200 mesh sieve to obtain zirconium-ruthenium co-doped lithium manganese oxide. Step A2: 0.05 mol 3,5-difluoro-4-hydroxybenzonitrile, 0.055 mol 1-bromohexane, and 0.2 mol potassium carbonate were added to a three-necked flask equipped with a thermometer and a stirrer. Nitrogen gas was introduced, and 300 mL of butanone was added and stirred for 10 min. The mixture was heated to 80 °C and stirred for 36 h. After cooling and filtration, the filtrate was concentrated by rotary evaporation and added to ethyl acetate. The filtrate was washed three times with saturated sodium chloride solution, dried with anhydrous magnesium sulfate, and purified by silica gel column chromatography in a petroleum ether-ethyl acetate mixed solvent (volume ratio of petroleum ether to ethyl acetate was 8:1) to obtain hexyl difluorobenzonitrile. Step A3: Add 0.8 mol sodium and 1 mmol ferric chloride to a three-necked flask equipped with a thermometer and a stirrer, purge with nitrogen, add 300 mL isoamyl alcohol and reflux for 6 h, add 0.1 mol hexyl difluorobenzonitrile, add 86 mmol diisopropyl succinate using a peristaltic pump, controlling the addition time at 2 h, cool, add to a methanol-formic acid mixed solution (methanol to formic acid volume ratio of 45:1), filter, wash with hot methanol until the filtrate is clear, dry, and obtain the first intermediate product; Step A4: Add 40 mmol of phosphorus oxychloride, 4 mmol of the first intermediate, 10 mmol of 2-acetonitrile-5-nitropyridine, and 400 mL of tetrahydrofuran to a four-necked flask equipped with a thermometer, stirrer, and reflux condenser. Purge with nitrogen, stir for 10 min, reflux for 12 h, remove tetrahydrofuran and phosphorus oxychloride by vacuum distillation, add to dichloromethane, wash with sodium bicarbonate solution to adjust pH to 7, separate the organic phase, dry with anhydrous magnesium sulfate, filter, concentrate, add to methanol to precipitate, filter, wash with methanol until the filtrate is clear, purify by silica gel column chromatography with a mixed solvent of n-hexane and ethyl acetate (volume ratio of n-hexane to ethyl acetate is 8:1), dry, and obtain the second intermediate. Step A5: Add 200 mmol of reduced iron powder, 100 mmol of ammonium chloride and 480 mL of ethanol-water solution (ethanol to water volume ratio of 3:1) to a three-necked flask equipped with a thermometer, stirrer and reflux condenser. Reflux and stir. Dissolve 25 mmol of the second intermediate product in 60 mL of dichloromethane and add it dropwise to the flask. React for 6 h. Filter the iron powder with diatomaceous earth. Remove dichloromethane and ethanol by rotary evaporation. Filter, wash 5 times with hot water and 2 times with ethanol. Dry to obtain the third intermediate product. Step A6: 10 mmol of 1,3,5-tribromobenzene, 60 mL of tetrahydrofuran, 0.3 mmol of tetra(triphenylphosphine)palladium, 30 mmol of 2-aldehydethiophene-4-boronic acid, and 15 mL of 1 mol / L potassium carbonate solution were added to a three-necked flask equipped with a stirrer and thermometer. Argon gas was introduced, and the mixture was stirred for 10 min. The mixture was reacted at 90 °C for 6 h. The mixture was then added to an ice-saturated sodium chloride solution and extracted three times with dichloromethane. The organic phases were combined and concentrated. The mixture was purified by silica gel column chromatography with a hexane-ethyl acetate mixed solvent (hexane to ethyl acetate volume ratio of 3:1). After drying, the fourth intermediate product was obtained. Step A7: Add 1g of zirconium-ruthenium co-doped lithium manganese oxide and 20mL of anhydrous ethanol to a single-necked flask equipped with a thermometer, sonicate for 20min, add 0.45mmol of the third intermediate, 0.68mmol of the fourth intermediate, 0.5mL of 1,4-dioxane and 0.75mL of 6mol / L glacial acetic acid, freeze in a liquid nitrogen bath, vacuum, seal and react at 120℃ for 72h, collect the solid and wash it 5 times with N,N-dimethylformamide and tetrahydrofuran, filter by sedimentation, place in a drying oven and vacuum dry at 100℃ for 6h to obtain fluoropyrrolethienyl COF-coated zirconium-ruthenium co-doped lithium manganese oxide; Step A8: Weigh out 50 parts of fluoropyrrolethiophene-based COF-coated zirconium-ruthenium co-doped lithium manganese oxide, 10 parts of acetylene black, and 6 parts of polyvinylidene fluoride according to the weight ratio, and set aside; wherein, the polyvinylidene fluoride is of type PVDF5130; Step A9: The fluoropyrrolethiophene-based COF-coated zirconium-ruthenium co-doped lithium manganese oxide, acetylene black, and polyvinylidene fluoride were ground, and then N-methylpyrrolidone was added to adjust the solid content to 45% and magnetically stirred for 3 hours. The mixture was then coated onto carbon-coated aluminum foil using a coating machine and placed in a drying oven for vacuum drying at 70°C for 12 hours. Finally, the mixture was stamped into a circular electrode using a slicing machine to obtain the doped and coated high-rate lithium manganese oxide cathode material.

[0032] Example 2: This embodiment describes a method for preparing a doped and coated high-rate lithium manganese oxide cathode material, including the following steps: Step A1: Add 0.099 mol manganese tetroxide, 0.07875 mol lithium carbonate, 0.0015 mol zirconium dioxide, and 0.0015 mol ruthenium dioxide to a ball mill jar. The mass ratio of raw materials to milling beads is 1:10. Add 75 mL of anhydrous ethanol and ball mill at 400 r / min for 4 h. After drying, grind the mixture and sieve it through a 200 mesh sieve. Place the mixture in a crucible in a muffle furnace and heat it to 450 °C at a heating rate of 6 °C / min. Hold the temperature for 2 h, then heat it to 800 °C and hold it for 10 h. Cool the mixture, grind it, and sieve it through a 200 mesh sieve to obtain zirconium-ruthenium co-doped lithium manganese oxide. Step A2: 0.075 mol 3,5-difluoro-4-hydroxybenzonitrile, 0.0825 mol 1-bromohexane, and 0.3 mol potassium carbonate were added to a three-necked flask equipped with a thermometer and a stirrer. Nitrogen gas was introduced, and 450 mL of butanone was added and stirred for 15 min. The mixture was heated to 80 °C and stirred for 42 h. After cooling and filtration, the filtrate was concentrated by rotary evaporation and added to ethyl acetate. The filtrate was washed four times with saturated sodium chloride solution, dried with anhydrous magnesium sulfate, and purified by silica gel column chromatography in a petroleum ether-ethyl acetate mixed solvent (volume ratio of petroleum ether to ethyl acetate was 8:1) to obtain hexyl difluorobenzonitrile. Step A3: Add 1.2 mol sodium and 1.5 mmol ferric chloride to a three-necked flask equipped with a thermometer and a stirrer, purge with nitrogen, add 450 mL isoamyl alcohol and reflux for 7 h, add 0.15 mol hexyl difluorobenzonitrile, add 129 mmol diisopropyl succinate using a peristaltic pump, controlling the addition time at 2 h, cool, add to a methanol-formic acid mixed solution (methanol to formic acid volume ratio of 45:1), filter, wash with hot methanol until the filtrate is clear, dry, and obtain the first intermediate product; Step A4: Add 60 mmol of phosphorus oxychloride, 6 mmol of the first intermediate, 15 mmol of 2-acetonitrile-5-nitropyridine, and 600 mL of tetrahydrofuran to a four-necked flask equipped with a thermometer, stirrer, and reflux condenser. Purge with nitrogen, stir for 15 min, reflux for 13 h, remove tetrahydrofuran and phosphorus oxychloride by vacuum distillation, add to dichloromethane, wash with sodium bicarbonate solution to adjust pH to 7, separate the organic phase, dry with anhydrous magnesium sulfate, filter, concentrate, add to methanol to precipitate, filter, wash with methanol until the filtrate is clear, purify by silica gel column chromatography with a hexane-ethyl acetate mixed solvent (hexane to ethyl acetate volume ratio of 8:1), dry, and obtain the second intermediate. Step A5: Add 300 mmol of reduced iron powder, 150 mmol of ammonium chloride, and 720 mL of ethanol-water solution (ethanol to water volume ratio of 3:1) to a three-necked flask equipped with a thermometer, stirrer, and reflux condenser. Reflux and stir. Dissolve 37.5 mmol of the second intermediate product in 90 mL of dichloromethane and add it dropwise to the flask. React for 6 h. Filter the iron powder with diatomaceous earth. Remove dichloromethane and ethanol by rotary evaporation. Filter, wash 6 times with hot water, wash 3 times with ethanol, and dry to obtain the third intermediate product. Step A6: 15 mmol of 1,3,5-tribromobenzene, 90 mL of tetrahydrofuran, 0.45 mmol of tetra(triphenylphosphine)palladium, 45 mmol of 2-aldehydethiophene-4-boronic acid, and 22.5 mL of 1 mol / L potassium carbonate solution were added to a three-necked flask equipped with a stirrer and thermometer. Argon gas was introduced, and the mixture was stirred for 15 min. The mixture was reacted at 90 °C for 6 h. The mixture was then added to an ice-saturated sodium chloride solution and extracted four times with dichloromethane. The organic phases were combined and concentrated. The mixture was purified by silica gel column chromatography with a hexane-ethyl acetate mixed solvent (hexane to ethyl acetate volume ratio of 3:1). After drying, the fourth intermediate product was obtained. Step A7: Add 1.5g of zirconium-ruthenium co-doped lithium manganese oxide and 30mL of anhydrous ethanol to a single-necked flask equipped with a thermometer, sonicate for 20min, add 0.675mmol of the third intermediate, 1.02mmol of the fourth intermediate, 0.75mL of 1,4-dioxane and 1.125mL of 6mol / L glacial acetic acid, freeze in a liquid nitrogen bath, evacuate, seal and react at 120℃ for 72h, collect the solid and wash it 6 times with N,N-dimethylformamide and tetrahydrofuran, filter by sedimentation, place in a drying oven and dry under vacuum at 100℃ for 6h to obtain fluoropyrrolethienyl COF-coated zirconium-ruthenium co-doped lithium manganese oxide; Step A8: Weigh out 75 parts of fluoropyrrolethiophene-based COF-coated zirconium-ruthenium co-doped lithium manganese oxide, 15 parts of acetylene black, and 9 parts of polyvinylidene fluoride according to the weight ratio, and set aside; wherein, the polyvinylidene fluoride is of type PVDF5130; Step A9: Fluoropyrrolethiophene-based COF-coated zirconium-ruthenium co-doped lithium manganese oxide, acetylene black, and polyvinylidene fluoride are ground, and then N-methylpyrrolidone is added to adjust the solid content to 50% and magnetically stirred for 3 hours. The mixture is then coated onto carbon-coated aluminum foil using a coating machine and placed in a drying oven for vacuum drying at 70°C for 12 hours. Finally, it is stamped into a circular electrode using a slicing machine to obtain a doped and coated high-rate lithium manganese oxide cathode material.

[0033] Example 3: This embodiment describes a method for preparing a doped and coated high-rate lithium manganese oxide cathode material, including the following steps: Step A1: Add 0.132 mol manganese tetroxide, 0.105 mol lithium carbonate, 0.002 mol zirconium dioxide, and 0.002 mol ruthenium dioxide to a ball mill jar. The mass ratio of raw materials to milling beads is 1:10. Add 100 mL of anhydrous ethanol and ball mill at 400 r / min for 4 h. After drying, grind the mixture and sieve it through a 200 mesh sieve. Place the mixture in a crucible in a muffle furnace and heat it to 450 °C at a heating rate of 6 °C / min. Hold the temperature for 2 h, then heat it to 800 °C and hold it for 10 h. Cool the mixture, grind it, and sieve it through a 200 mesh sieve to obtain zirconium-ruthenium co-doped lithium manganese oxide. Step A2: 0.1 mol of 3,5-difluoro-4-hydroxybenzonitrile, 0.11 mol of 1-bromohexane, and 0.4 mol of potassium carbonate were added to a three-necked flask equipped with a thermometer and a stirrer. Nitrogen gas was introduced, and 600 mL of butanone was added and stirred for 20 min. The mixture was heated to 80 °C and stirred for 48 h. After cooling and filtration, the filtrate was concentrated by rotary evaporation and added to ethyl acetate. The filtrate was washed five times with saturated sodium chloride solution, dried with anhydrous magnesium sulfate, and purified by silica gel column chromatography in a petroleum ether-ethyl acetate mixed solvent (volume ratio of petroleum ether to ethyl acetate was 8:1) to obtain hexyl difluorobenzonitrile. Step A3: Add 1.6 mol sodium and 2 mmol ferric chloride to a three-necked flask equipped with a thermometer and a stirrer, purge with nitrogen, add 600 mL isoamyl alcohol and reflux for 8 h, add 0.2 mol hexyl difluorobenzonitrile, add 172 mmol diisopropyl succinate using a peristaltic pump, controlling the addition time at 2 h, cool, add to a methanol-formic acid mixed solution (methanol to formic acid volume ratio of 45:1), filter, wash with hot methanol until the filtrate is clear, dry, and obtain the first intermediate product; Step A4: Add 80 mmol of phosphorus oxychloride, 8 mmol of the first intermediate, 20 mmol of 2-acetonitrile-5-nitropyridine, and 800 mL of tetrahydrofuran to a four-necked flask equipped with a thermometer, stirrer, and reflux condenser. Purge with nitrogen, stir for 20 min, reflux for 15 h, remove tetrahydrofuran and phosphorus oxychloride by vacuum distillation, add to dichloromethane, wash with sodium bicarbonate solution to adjust pH to 7, separate the organic phase, dry with anhydrous magnesium sulfate, filter, concentrate, add to methanol to precipitate, filter, wash with methanol until the filtrate is clear, purify by silica gel column chromatography with a mixed solvent of n-hexane and ethyl acetate (volume ratio of n-hexane to ethyl acetate is 8:1), dry, and obtain the second intermediate. Step A5: Add 400 mmol of reduced iron powder, 200 mmol of ammonium chloride, and 960 mL of ethanol-water solution (ethanol to water volume ratio of 3:1) to a three-necked flask equipped with a thermometer, stirrer, and reflux condenser. Reflux and stir. Dissolve 50 mmol of the second intermediate in 120 mL of dichloromethane and add it dropwise to the flask. React for 6 h. Filter the iron powder with diatomaceous earth. Remove dichloromethane and ethanol by rotary evaporation. Filter, wash 7 times with hot water, wash 4 times with ethanol, and dry to obtain the third intermediate. Step A6: 20 mmol of 1,3,5-tribromobenzene, 120 mL of tetrahydrofuran, 0.6 mmol of tetra(triphenylphosphine)palladium, 60 mmol of 2-aldehydethiophene-4-boronic acid, and 30 mL of 1 mol / L potassium carbonate solution were added to a three-necked flask equipped with a stirrer and thermometer. Argon gas was introduced, and the mixture was stirred for 20 min. The mixture was reacted at 90 °C for 6 h. The mixture was then added to an ice-saturated sodium chloride solution and extracted five times with dichloromethane. The organic phases were combined and concentrated. The mixture was purified by silica gel column chromatography with a hexane-ethyl acetate mixed solvent (hexane to ethyl acetate volume ratio of 3:1). After drying, the fourth intermediate product was obtained. Step A7: Add 2g of zirconium-ruthenium co-doped lithium manganese oxide and 40mL of anhydrous ethanol to a single-necked flask equipped with a thermometer, sonicate for 20min, add 0.9mmol of the third intermediate, 1.36mmol of the fourth intermediate, 1mL of 1,4-dioxane and 1.5mL of 6mol / L glacial acetic acid, freeze in a liquid nitrogen bath, vacuum, seal and react at 120℃ for 72h, collect the solid and wash it 7 times with N,N-dimethylformamide and tetrahydrofuran, filter by sedimentation, place in a drying oven and vacuum dry at 100℃ for 6h to obtain fluoropyrrolethienyl COF-coated zirconium-ruthenium co-doped lithium manganese oxide; Step A8: Weigh out 100 parts by weight of fluoropyrrolethiophene-based COF-coated zirconium-ruthenium co-doped lithium manganese oxide, 20 parts by weight of acetylene black and 12 parts by weight of polyvinylidene fluoride, and set aside; wherein, the polyvinylidene fluoride is of type PVDF5130; Step A9: The fluoropyrrolethiophene-based COF-coated zirconium-ruthenium co-doped lithium manganese oxide, acetylene black, and polyvinylidene fluoride were ground, and then N-methylpyrrolidone was added to adjust the solid content to 55% and magnetically stirred for 3 hours. The mixture was then coated onto carbon-coated aluminum foil using a coating machine and placed in a drying oven for vacuum drying at 70°C for 12 hours. Finally, the mixture was stamped into a circular electrode using a slicing machine to obtain a doped and coated high-rate lithium manganese oxide cathode material.

[0034] Comparative Example 1: This comparative example illustrates a method for preparing a doped and coated high-rate lithium manganese oxide cathode material, comprising the following steps: Step A1: Add 0.132 mol manganese tetroxide, 0.105 mol lithium carbonate, 0.002 mol zirconium dioxide, and 0.002 mol ruthenium dioxide to a ball mill jar. The mass ratio of raw materials to milling beads is 1:10. Add 100 mL of anhydrous ethanol and ball mill at 400 r / min for 4 h. After drying, grind the mixture and sieve it through a 200 mesh sieve. Place the mixture in a crucible in a muffle furnace and heat it to 450 °C at a heating rate of 6 °C / min. Hold the temperature for 2 h, then heat it to 800 °C and hold it for 10 h. Cool the mixture, grind it, and sieve it through a 200 mesh sieve to obtain zirconium-ruthenium co-doped lithium manganese oxide. Step A2: Weigh out 100 parts by weight of zirconium-ruthenium co-doped lithium manganese oxide, 20 parts by weight of acetylene black and 12 parts by weight of polyvinylidene fluoride, and set aside; wherein, the polyvinylidene fluoride is of type PVDF5130; Step A3: Zirconium-ruthenium co-doped lithium manganese oxide, acetylene black, and polyvinylidene fluoride are ground, and then N-methylpyrrolidone is added to adjust the solid content to 55% and magnetically stirred for 3 hours. The mixture is then coated onto carbon-coated aluminum foil using a coating machine and placed in a drying oven for vacuum drying at 70°C for 12 hours. Finally, it is punched into a circular electrode using a slicing machine to obtain a doped high-rate lithium manganese oxide cathode material.

[0035] Comparative Example 2: This comparative example illustrates a method for preparing a coated high-rate lithium manganese oxide cathode material, comprising the following steps: Step A1: Add 0.132 mol manganese tetroxide and 0.105 mol lithium carbonate to a ball mill jar. The mass ratio of raw material to milling beads is 1:10. Add 100 mL of anhydrous ethanol and ball mill at 400 r / min for 4 h. After drying, grind and sieve through a 200 mesh sieve. Place the sieve in a crucible and put it in a muffle furnace. Heat the crucible to 450 °C at a heating rate of 6 °C / min and hold for 2 h. Then heat the crucible to 800 °C and hold for 10 h. Cool and grind the sieve through a 200 mesh sieve to obtain lithium manganese oxide. Step A2: 0.1 mol of 3,5-difluoro-4-hydroxybenzonitrile, 0.11 mol of 1-bromohexane, and 0.4 mol of potassium carbonate were added to a three-necked flask equipped with a thermometer and a stirrer. Nitrogen gas was introduced, and 600 mL of butanone was added and stirred for 20 min. The mixture was heated to 80 °C and stirred for 48 h. After cooling and filtration, the filtrate was concentrated by rotary evaporation and added to ethyl acetate. The filtrate was washed five times with saturated sodium chloride solution, dried with anhydrous magnesium sulfate, and purified by silica gel column chromatography in a petroleum ether-ethyl acetate mixed solvent (volume ratio of petroleum ether to ethyl acetate was 8:1) to obtain hexyl difluorobenzonitrile. Step A3: Add 1.6 mol sodium and 2 mmol ferric chloride to a three-necked flask equipped with a thermometer and a stirrer, purge with nitrogen, add 600 mL isoamyl alcohol and reflux for 8 h, add 0.2 mol hexyl difluorobenzonitrile, add 172 mmol diisopropyl succinate using a peristaltic pump, controlling the addition time at 2 h, cool, add to a methanol-formic acid mixed solution (methanol to formic acid volume ratio of 45:1), filter, wash with hot methanol until the filtrate is clear, dry, and obtain the first intermediate product; Step A4: Add 80 mmol of phosphorus oxychloride, 8 mmol of the first intermediate, 20 mmol of 2-acetonitrile-5-nitropyridine, and 800 mL of tetrahydrofuran to a four-necked flask equipped with a thermometer, stirrer, and reflux condenser. Purge with nitrogen, stir for 20 min, reflux for 15 h, remove tetrahydrofuran and phosphorus oxychloride by vacuum distillation, add to dichloromethane, wash with sodium bicarbonate solution to adjust pH to 7, separate the organic phase, dry with anhydrous magnesium sulfate, filter, concentrate, add to methanol to precipitate, filter, wash with methanol until the filtrate is clear, purify by silica gel column chromatography with a mixed solvent of n-hexane and ethyl acetate (volume ratio of n-hexane to ethyl acetate is 8:1), dry, and obtain the second intermediate. Step A5: Add 400 mmol of reduced iron powder, 200 mmol of ammonium chloride, and 960 mL of ethanol-water solution (ethanol to water volume ratio of 3:1) to a three-necked flask equipped with a thermometer, stirrer, and reflux condenser. Reflux and stir. Dissolve 50 mmol of the second intermediate in 120 mL of dichloromethane and add it dropwise to the flask. React for 6 h. Filter the iron powder with diatomaceous earth. Remove dichloromethane and ethanol by rotary evaporation. Filter, wash 7 times with hot water, wash 4 times with ethanol, and dry to obtain the third intermediate. Step A6: 20 mmol of 1,3,5-tribromobenzene, 120 mL of tetrahydrofuran, 0.6 mmol of tetra(triphenylphosphine)palladium, 60 mmol of 2-aldehydethiophene-4-boronic acid, and 30 mL of 1 mol / L potassium carbonate solution were added to a three-necked flask equipped with a stirrer and thermometer. Argon gas was introduced, and the mixture was stirred for 20 min. The mixture was reacted at 90 °C for 6 h. The mixture was then added to an ice-saturated sodium chloride solution and extracted five times with dichloromethane. The organic phases were combined and concentrated. The mixture was purified by silica gel column chromatography with a hexane-ethyl acetate mixed solvent (hexane to ethyl acetate volume ratio of 3:1). After drying, the fourth intermediate product was obtained. Step A7: Add 2g of lithium manganese oxide and 40mL of anhydrous ethanol to a single-necked flask equipped with a thermometer, sonicate for 20min, add 0.9mmol of the third intermediate, 1.36mmol of the fourth intermediate, 1mL of 1,4-dioxane and 1.5mL of 6mol / L glacial acetic acid, freeze in a liquid nitrogen bath, vacuum, seal and react at 120℃ for 72h, collect the solid and wash it 7 times with N,N-dimethylformamide and tetrahydrofuran, filter by sedimentation, place in a drying oven and vacuum dry at 100℃ for 6h to obtain fluoropyrrolethiophene-based COF-coated lithium manganese oxide; Step A8: Weigh out 100 parts of fluoropyrrolethiophene-based COF-coated lithium manganese oxide, 20 parts of acetylene black, and 12 parts of polyvinylidene fluoride according to the weight ratio, and set aside; wherein, the polyvinylidene fluoride is of type PVDF5130. Step A9: Fluoropyrrolothiophene-based COF-coated lithium manganese oxide, acetylene black, and polyvinylidene fluoride are ground, and then N-methylpyrrolidone is added to adjust the solid content to 55% and magnetically stirred for 3 hours. The mixture is then coated onto carbon-coated aluminum foil using a coating machine and placed in a drying oven for vacuum drying at 70°C for 12 hours. Finally, it is punched into a circular electrode using a slicing machine to obtain the coated high-rate lithium manganese oxide cathode material.

[0036] Comparative Example 3: This comparative example illustrates a method for preparing a doped and coated high-rate lithium manganese oxide cathode material, comprising the following steps: Step A1: Add 0.132 mol manganese tetroxide, 0.105 mol lithium carbonate, and 0.002 mol zirconium dioxide to a ball mill jar. The mass ratio of raw materials to milling beads is 1:10. Add 100 mL of anhydrous ethanol and ball mill at 400 r / min for 4 h. After drying, grind and sieve through a 200 mesh sieve. Place the mixture in a crucible in a muffle furnace and heat it to 450 °C at a heating rate of 6 °C / min and hold for 2 h. Then heat it to 800 °C and hold for 10 h. After cooling and grinding, sieve through a 200 mesh sieve to obtain zirconium-doped lithium manganese oxide. Step A2: 0.1 mol of 3,5-difluoro-4-hydroxybenzonitrile, 0.11 mol of 1-bromohexane, and 0.4 mol of potassium carbonate were added to a three-necked flask equipped with a thermometer and a stirrer. Nitrogen gas was introduced, and 600 mL of butanone was added and stirred for 20 min. The mixture was heated to 80 °C and stirred for 48 h. After cooling and filtration, the filtrate was concentrated by rotary evaporation and added to ethyl acetate. The filtrate was washed five times with saturated sodium chloride solution, dried with anhydrous magnesium sulfate, and purified by silica gel column chromatography in a petroleum ether-ethyl acetate mixed solvent (volume ratio of petroleum ether to ethyl acetate was 8:1) to obtain hexyl difluorobenzonitrile. Step A3: Add 1.6 mol sodium and 2 mmol ferric chloride to a three-necked flask equipped with a thermometer and a stirrer, purge with nitrogen, add 600 mL isoamyl alcohol and reflux for 8 h, add 0.2 mol hexyl difluorobenzonitrile, add 172 mmol diisopropyl succinate using a peristaltic pump, controlling the addition time at 2 h, cool, add to a methanol-formic acid mixed solution (methanol to formic acid volume ratio of 45:1), filter, wash with hot methanol until the filtrate is clear, dry, and obtain the first intermediate product; Step A4: Add 80 mmol of phosphorus oxychloride, 8 mmol of the first intermediate, 20 mmol of 2-acetonitrile-5-nitropyridine, and 800 mL of tetrahydrofuran to a four-necked flask equipped with a thermometer, stirrer, and reflux condenser. Purge with nitrogen, stir for 20 min, reflux for 15 h, remove tetrahydrofuran and phosphorus oxychloride by vacuum distillation, add to dichloromethane, wash with sodium bicarbonate solution to adjust pH to 7, separate the organic phase, dry with anhydrous magnesium sulfate, filter, concentrate, add to methanol to precipitate, filter, wash with methanol until the filtrate is clear, purify by silica gel column chromatography with a mixed solvent of n-hexane and ethyl acetate (volume ratio of n-hexane to ethyl acetate is 8:1), dry, and obtain the second intermediate. Step A5: Add 400 mmol of reduced iron powder, 200 mmol of ammonium chloride, and 960 mL of ethanol-water solution (ethanol to water volume ratio of 3:1) to a three-necked flask equipped with a thermometer, stirrer, and reflux condenser. Reflux and stir. Dissolve 50 mmol of the second intermediate in 120 mL of dichloromethane and add it dropwise to the flask. React for 6 h. Filter the iron powder with diatomaceous earth. Remove dichloromethane and ethanol by rotary evaporation. Filter, wash 7 times with hot water, wash 4 times with ethanol, and dry to obtain the third intermediate. Step A6: Add 2g of zirconium-doped lithium manganese oxide and 40mL of anhydrous ethanol to a single-necked flask equipped with a thermometer, sonicate for 20min, add 0.9mmol of the third intermediate, 1.36mmol of trialdehyde resorcinol, 1mL of 1,4-dioxane and 1.5mL of 6mol / L glacial acetic acid, freeze in a liquid nitrogen bath, vacuum, seal and react at 120℃ for 72h, collect the solid and wash it 7 times with N,N-dimethylformamide and tetrahydrofuran, filter by sedimentation, place in a drying oven and vacuum dry at 100℃ for 6h to obtain fluoropyrrole-coated zirconium-doped lithium manganese oxide; Step A7: Weigh out 100 parts of fluoropyrrole-coated zirconium-doped lithium manganese oxide, 20 parts of acetylene black, and 12 parts of polyvinylidene fluoride according to the following weight proportions, and set aside; wherein, the polyvinylidene fluoride is of type PVDF5130. Step A8: Fluoropyrrole-coated zirconium-doped lithium manganese oxide, acetylene black, and polyvinylidene fluoride are ground, and then N-methylpyrrolidone is added to adjust the solid content to 55% and magnetically stirred for 3 hours. The mixture is then coated onto carbon-coated aluminum foil using a coating machine and placed in a drying oven for vacuum drying at 70°C for 12 hours. Finally, it is stamped into a circular electrode using a slicing machine to obtain a doped and coated high-rate lithium manganese oxide cathode material.

[0037] Performance testing: See Figure 1 The microstructure and size of the fluoropyrrolethiophene-based COF-coated zirconium ruthenium co-doped lithium manganese oxide in Example 3 were analyzed using a field emission scanning electron microscope (S-4800), and the SEM images of the fluoropyrrolethiophene-based COF-coated zirconium ruthenium co-doped lithium manganese oxide in Example 3 were obtained. The positive electrode materials of Examples 1-3 and Comparative Examples 1-3 were assembled using a CR2032 button cell casing, with lithium foil as the negative electrode and Celgard2500 battery separator. 1M LiPF6 / (EC+EMC+DMC) (1:1:1, v / v / v) electrolyte was added to obtain the sample battery.

[0038] The Wuhan Landian LAND-CT2001A battery testing system was used, with a test voltage of 2.5-3.75V. During testing, a charge-then-discharge method was employed. Cyclic performance testing was performed at a current density of 1C for 100 cycles to obtain the capacity retention rate after 100 cycles. Rate performance testing was conducted at current densities of 0.2C, 0.5C, 1C, and 2C to obtain the rate performance.

[0039] Table 1. Discharge specific capacity and capacity retention after 100 cycles of cathode materials at 0.2C, 0.5C, 1C, and 2C.

[0040] Referring to the table above, based on the comparison between Examples 1-3 and Comparative Examples 1-3, it can be seen that the fluoropyrrolethiophene-based COF-coated zirconium-ruthenium co-doped lithium manganese oxide exhibits good rate performance and high capacity retention.

[0041] Based on the comparison between Example 3 and Comparative Example 1, it can be seen that the capacity retention rate of the cathode material obtained by coating zirconium and ruthenium co-doped lithium manganese oxide with fluoropyrrolethiophene-based COF is higher than that of the cathode material obtained by coating zirconium and ruthenium co-doped lithium manganese oxide, indicating that the cathode material obtained by coating zirconium and ruthenium co-doped lithium manganese oxide with fluoropyrrolethiophene-based COF has excellent cycle performance. Based on the comparison between Example 3 and Comparative Example 2, it can be seen that the capacity retention rate of the cathode material obtained by coating zirconium and ruthenium co-doped lithium manganese oxide with fluoropyrrolethiophene-based COF is higher than that of the cathode material obtained by coating lithium manganese oxide with fluoropyrrolethiophene-based COF, indicating that the cathode material obtained by coating zirconium and ruthenium co-doped lithium manganese oxide with fluoropyrrolethiophene-based COF has excellent cycle performance. Based on the comparison between Example 3 and Comparative Example 3, it can be seen that the capacity retention rate of the cathode material obtained by coating zirconium-ruthenium co-doped lithium manganese oxide with fluoropyrrole-thiophene-based COF is higher than that of the cathode material obtained by coating zirconium-doped lithium manganese oxide with fluoropyrrole-based COF, indicating that the cathode material obtained by coating zirconium-ruthenium co-doped lithium manganese oxide with fluoropyrrole-thiophene-based COF has excellent cycle performance.

[0042] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0043] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in this application, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a doped and coated high-rate lithium manganese oxide cathode material, characterized in that, Includes the following steps: Step 1: Weigh out 50-100 parts of fluoropyrrolethiophene-based COF-coated zirconium-ruthenium co-doped lithium manganese oxide, 10-20 parts of acetylene black, and 6-12 parts of polyvinylidene fluoride according to the weight ratio, and set aside. Step 2: The fluoropyrrolethiophene-based COF-coated zirconium-ruthenium co-doped lithium manganese oxide, acetylene black, and polyvinylidene fluoride were ground, and then N-methylpyrrolidone was added to adjust the solid content to 45%-55% and magnetically stirred for 3 hours. The mixture was then coated onto carbon-coated aluminum foil using a coating machine and placed in a drying oven for vacuum drying at 70°C for 12 hours. Finally, the mixture was stamped into a circular electrode using a slicing machine to obtain a doped and coated high-rate lithium manganese oxide cathode material. The fluoropyrrolethiophene-based COF-coated zirconium-ruthenium co-doped lithium manganese oxide is prepared by the following steps: Step A1: React manganese tetroxide, lithium carbonate, zirconium dioxide, ruthenium dioxide and anhydrous ethanol to obtain zirconium-ruthenium co-doped lithium manganate; Step A2: Stir 3,5-difluoro-4-hydroxybenzonitrile, 1-bromohexane, potassium carbonate and butanone to obtain hexyl difluorobenzonitrile; Step A3: Sodium, ferric chloride, isoamyl alcohol, hexyl difluorobenzonitrile and diisopropyl succinate are reacted to give the first intermediate product; Step A4: React phosphorus oxychloride, the first intermediate, 2-acetonitrile-5-nitropyridine, and tetrahydrofuran to obtain the second intermediate; Step A5: Stir the reduced iron powder, ammonium chloride, and ethanol aqueous solution, add the second intermediate and dichloromethane to react and obtain the third intermediate; Step A6: React 1,3,5-tribromobenzene, tetrahydrofuran, tetra(triphenylphosphine)palladium, 2-aldehydethiophene-4-boronic acid and potassium carbonate solution to obtain the fourth intermediate product; Step A7: Sonicate zirconium-ruthenium co-doped lithium manganese oxide with anhydrous ethanol, add third intermediate, fourth intermediate, 1,4-dioxane and glacial acetic acid to react and obtain fluoropyrrolethiophene-based COF-coated zirconium-ruthenium co-doped lithium manganese oxide.

2. The method for preparing a doped and coated high-rate lithium manganese oxide cathode material according to claim 1, characterized in that, The ratio of manganese tetroxide, lithium carbonate, zirconium dioxide, ruthenium dioxide, and anhydrous ethanol used in step A1 is 0.066-0.132 mol: 0.0525-0.105 mol: 0.001-0.002 mol: 0.001-0.002 mol: 50-100 mL.

3. The method for preparing a doped and coated high-rate lithium manganese oxide cathode material according to claim 1, characterized in that, The ratio of 3,5-difluoro-4-hydroxybenzonitrile, 1-bromohexane, potassium carbonate, and butanone used in step A2 is 0.05-0.1 mol: 0.055-0.11 mol: 0.2-0.4 mol: 300-600 mL.

4. The method for preparing a doped and coated high-rate lithium manganese oxide cathode material according to claim 1, characterized in that, The ratio of sodium, ferric chloride, isoamyl alcohol, hexyl difluorobenzonitrile, and diisopropyl succinate used in step A3 is 0.8-1.6 mol: 1-2 mmol: 300-600 mL: 0.1-0.2 mol: 86-172 mmol.

5. The method for preparing a doped and coated high-rate lithium manganese oxide cathode material according to claim 1, characterized in that, In step A4, the ratio of phosphorus oxychloride, the first intermediate product, 2-acetonitrile-5-nitropyridine, and tetrahydrofuran is 40-80 mmol: 4-8 mmol: 10-20 mmol: 400-800 mL.

6. The method for preparing a doped and coated high-rate lithium manganese oxide cathode material according to claim 1, characterized in that, The ratio of reduced iron powder, ammonium chloride, aqueous ethanol solution, second intermediate product and dichloromethane used in step A5 is 200-400 mmol: 100-200 mmol: 480-960 mL: 25-50 mmol: 60-120 mL.

7. The method for preparing a doped and coated high-rate lithium manganese oxide cathode material according to claim 1, characterized in that, In step A5, the volume ratio of ethanol to water in the aqueous ethanol solution is 3:

1.

8. The method for preparing a doped and coated high-rate lithium manganese oxide cathode material according to claim 1, characterized in that, In step A6, the ratio of 1,3,5-tribromobenzene, tetrahydrofuran, tetra(triphenylphosphine)palladium, 2-aldehydethiophene-4-boronic acid, and potassium carbonate solution is 10-20 mmol: 60-120 mL: 0.3-0.6 mmol: 30-60 mmol: 15-30 mL; the molar concentration of the potassium carbonate solution is 1 mol / L.

9. The method for preparing a doped and coated high-rate lithium manganese oxide cathode material according to claim 1, characterized in that, In step A7, the ratio of zirconium-ruthenium co-doped lithium manganese oxide, anhydrous ethanol, the third intermediate, the fourth intermediate, 1,4-dioxane, and glacial acetic acid is 1-2 g: 20-40 mL: 0.45-0.9 mmol: 0.68-1.36 mmol: 0.5-1 mL: 0.75-1.5 mL; the molar concentration of the glacial acetic acid is 6 mol / L.

10. A doped and coated high-rate lithium manganese oxide cathode material, characterized in that, The doped and coated high-rate lithium manganese oxide cathode material is prepared according to the preparation method of the doped and coated high-rate lithium manganese oxide cathode material according to any one of claims 1-9.

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