A lithium-rich manganese-based layered oxide composite cathode material and a preparation method thereof

Abstract

This invention discloses a lithium-rich manganese-based layered oxide composite cathode material and its preparation method, belonging to the field of lithium-ion battery technology. The method includes: adding water to a nickel source, a cobalt source, and a manganese source to obtain a mixed solution; adding sodium carbonate solution to adjust the pH; washing with deionized water and centrifuging; drying; mixing with lithium salt; and pre-calcining to obtain Li. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 The material was then subjected to a process involving the sequential addition of a carbon source and an organic solvent. The resulting mixture was heated under a mixed atmosphere to obtain a lithium-rich manganese-based basal oxide material. Na₂WO₄ and pyrrole were then added, and the mixture was dissolved in deionized water to obtain a composite cathode material, Li. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,S-C@Na2WO4@PPy. The composite cathode material of this invention has uniform particles, stable structure, and exhibits considerable wide potential window reversible capacity, excellent rate performance, and stable cycle life.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology, specifically relating to a lithium-rich manganese-based layered oxide composite cathode material and its preparation method. Background Technology

[0002] Traditional fossil fuels are facing a crisis of shortage or even depletion, putting enormous pressure on environmental protection. The new industrial development direction of circular economy and low-carbon economy will drive the rapid development of the new energy vehicle industry. Lithium-ion power batteries, as a new generation of environmentally friendly and high-energy batteries, have become the mainstream product for power batteries in new energy vehicles. However, since the commercialization of lithium-ion batteries in the 1990s, the capacity of cathode materials has been difficult to match with that of anode materials, resulting in a persistent overcapacity of anode materials. Lithium-rich manganese-based layered oxide cathode materials are widely used in lithium-ion batteries, possessing advantages such as high specific capacity, long cycle life, and low cost, and are considered one of the important research directions in the field of lithium-ion batteries. Over the past few decades, researchers have conducted extensive research on lithium-rich manganese-based layered oxide cathode materials and made significant progress. Although lithium-rich cathode materials have high theoretical energy density, during charging and discharging, due to severe electrolyte side reactions and slow ion transport, the battery's specific capacity and voltage decay significantly, resulting in problems such as low measured energy density, short cycle life, and low coulombic efficiency. Therefore, the development of high-energy-density lithium-ion power batteries has become a hot topic and focus in the field of battery research. In terms of the application of novel electrode materials, the most noteworthy is lithium-rich manganese-based layered oxide cathode materials, with a specific capacity of 200-300 mAh / g. However, these materials exhibit poor cycle performance and low initial coulombic efficiency. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a lithium-rich manganese-based layered oxide composite cathode material and its preparation method. This synthesis method is simple, highly controllable, and uses inexpensive and widely available raw materials. The resulting material has uniform particle size and high crystallinity, which improves the electronic and ionic conductivity of the material, resulting in high reversible capacity and excellent cycle stability. Thus, while reducing the material preparation cost, it can effectively improve the lithium storage performance of the lithium-rich manganese-based layered oxide cathode material.

[0004] The technical solution adopted by this invention to solve the above-mentioned technical problems is: a lithium-rich manganese-based layered oxide composite cathode material Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 The preparation method of @N,SC@Na2WO4@PPy includes the following steps:

[0005] (1) Dissolve the nickel source, cobalt source and manganese source in deionized water and stir to obtain a salt solution;

[0006] (2) Heat the deionized water; then, under stirring conditions, slowly add the saturated Na2CO3 solution and the salt solution from step (1) into the above deionized water, and adjust the pH of the resulting reaction solution with an alkaline substance.

[0007] (3) After all the salt solution and Na2CO3 solution in step (2) have been added, continue to add alkaline substances to adjust the pH, then stir, centrifuge and wash to obtain the precipitate; vacuum dry the precipitate to obtain the precursor;

[0008] (4) The precursor from step (3) is mixed with lithium salt, and then the resulting mixture is pre-calcined; then calcined in air to obtain Li. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 Material;

[0009] (5) Take Li from step (4) 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 The material and carbon source are mixed with an organic solvent, ultrasonically dispersed, stirred, and the organic solvent is removed by rotary evaporation to obtain a mixture.

[0010] (6) The mixture from step (5) is heated under a mixed atmosphere and cooled to room temperature to obtain a lithium-rich manganese-based matrix oxide Li co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC materials; 0.9–1 g of lithium-rich manganese-based layered oxides co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC material, 0.01–0.1 g of Na₂WO₄ and 0.8 mL of pyrrole monomer were dissolved in 100 mL of deionized water, heated and stirred to obtain a residual mixture, which was then vacuum dried to obtain a lithium-rich manganese-based layered oxide composite cathode material Li₂O₃, co-coated with nitrogen-sulfur-doped carbon and polypyrrole (PPy). 1.2 Ni 0.13 Co0.13 Mn 0.54 O 1.8 F 0.2 @N,SC@Na2WO4@PPy.

[0011] The nickel source mentioned in step 1 is a mixture of Ni(NO3)2·6H2O and Ni(CH3COO)2·4H2O, with a molar ratio of Ni(NO3)2·6H2O to Ni(CH3COO)2·4H2O of 10:(1-10); the cobalt source is a mixture of Co(NO3)2·6H2O and Co(CH3COO)2·4H2O, with a molar ratio of Co(NO3)2·6H2O to Co(CH3COO)2·4H2O of 10:(1-10); the manganese source is a mixture of Mn(NO3)2·6H2O and Mn(CH3COO)2·4H2O, with a molar ratio of Mn(NO3)2·6H2O to Mn(CH3COO)2·4H2O of 10:(1-10).

[0012] In step 1, the molar ratio of the nickel source, cobalt source, and manganese source is 13:13:54; the stirring time is 2–3 hours; and the concentration of the salt solution is 2.0 mol·L⁻¹. -1 ;

[0013] The heating in step 2 involves adding deionized water to the reaction flask and heating it to 60-70°C; the stirring specifically involves using a magnetic heating stirrer to maintain the temperature at 60-70°C under an inert atmosphere, wherein the inert atmosphere is N2.

[0014] The volume ratio of the deionized water mentioned in step 2 to the salt solution and the saturated Na2CO3 solution in step 1 is 1:1:(1~1.5).

[0015] The slow dripping mentioned in step 2 refers to using a peristaltic pump to drip at a rate of 80-90 μL / min;

[0016] The alkaline substance mentioned in step 2 is a mixed solution of 13.5-15 mol / L ammonia water and 5-7 mol / L NaOH, and the volume ratio of the alkaline substance to the ammonia water is (1.5-2):1;

[0017] The pH value mentioned in step 2 is adjusted to 7.8–8.2;

[0018] The pH adjustment mentioned in step 3 is to adjust it to 8.5;

[0019] The stirring described in step 3 is performed at 60–70°C for 12–15 hours;

[0020] The washing in step 3 is performed with hydrochloric acid at a concentration of 1-1.5 mol / L; the centrifugation is carried out at room temperature at a speed of 3000-5000 r / min.

[0021] The vacuum drying temperature in step 3 is 80-85℃, and the drying time is 12-15 hours.

[0022] The lithium salt mentioned in step 4 is a mixture of Li2CO3 and Li2F, with a molar ratio of Li2CO3 to Li2F of (5-5.4):1; the lithium salt is mixed with the precursor at a molar ratio of Li:(Ni+Co+Mn) of (3-3.6):2.

[0023] The pre-calcination described in step 4 involves transferring the mixture into a muffle furnace, with a pre-calcination temperature of 500–550°C and a pre-calcination time of 3.5–4 hours.

[0024] The calcination temperature in step 4 is 900–950°C, and the calcination time is 15–16 hours.

[0025] The carbon source mentioned in step 5 is a mixture of medium-temperature coal tar pitch, ethylenediaminetetraacetic acid (EDTA), and thiourea, with a mass ratio of 3:(2-3):(4-5).

[0026] The organic solvent mentioned in step 5 is a mixture of acetone, ethylene glycol and anhydrous ethanol, with a volume ratio of 5:1:4.

[0027] The Li mentioned in step 5 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 The mass ratio of the material to the carbon source is 1:10; the volume ratio of the organic solvent to the mass of the carbon source is 20:1 (mL / g);

[0028] The ultrasonic dispersion time in step 5 is 1-2 hours; the stirring is performed using strong magnetic stirring for 12-15 hours.

[0029] The mixed atmosphere mentioned in step 6 is a mixture of NH3 and N2, with a volume ratio of NH3 to N2 of 1:9;

[0030] The heating described in step 6 is to raise the temperature to 350-450℃ and hold it at that temperature for 4.5-5 hours;

[0031] The heating and stirring described in step 6 is to stir at 80-85°C for 3-5 hours;

[0032] The vacuum drying described in step 6 is performed at a drying temperature of 60–80°C for a drying time of 24–26 hours.

[0033] The lithium-rich manganese-based layered oxide composite cathode material coated with fluorine-doped Na2WO4 obtained by the above preparation method is used as a cathode for lithium-ion batteries.

[0034] Compared with the prior art, the present invention has the following technical effects:

[0035] 1. This invention employs nitrogen- and sulfur-doped carbon, sodium tungstate, and polypyrrole to co-coat Li. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 A lithium-manganese-based layered oxide composite cathode material was prepared using a material-specific method. The synergistic effect of N and S doping and the three-dimensional cross-linked carbon network significantly improved the conductivity of the electrode material, while polypyrrole itself possesses excellent conductivity. The similar ionic radii of F and O ions allow F to partially replace lattice oxygen sites in the metal oxide; F has extremely high electronegativity, which stabilizes the oxide structure. Na₂WO₄ plays a coating role in the composite material, and Li… 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 The Na₂WO₄-filled shell ensures uniform and dense dispersion of the composite material, maintaining the stability and high conductivity of the electrode structure. This doping and co-coating layer not only provides a highly conductive nanolayer between particles, giving them low charge transfer resistance and high conductivity, but also hinders direct contact between the particles and the electrolyte, reducing electrolyte corrosion of the particles.

[0036] 2. The material synthesized by this invention has uniform and consistent particle size, good dispersibility, and high crystallinity. The resulting material is in the form of nanorods, which is beneficial to improving the electrochemical performance of the material.

[0037] 3. The material obtained by this invention has a considerable wide potential window reversible capacity, excellent rate performance and stable cycle life, which makes the material have high practical value and can effectively meet the actual requirements of various applications of lithium-ion batteries.

[0038] 4. The lithium-ion battery cathode material prepared by this invention has high theoretical capacity and fast charge and discharge performance, which improves the energy density and power density of lithium-ion batteries. Attached Figure Description

[0039] Figure 1This invention relates to Example 1, a lithium-rich manganese-based base oxide (Li) co-coated with polypyrrole and nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 SEM image of the @N,SC@Na2WO4@PPy composite cathode material;

[0040] Figure 2 The lithium-rich manganese-based base oxide Li, co-coated with polypyrrole and nitrogen-sulfur-doped carbon in Example 1 of this invention, is a lithium-rich manganese-based base oxide. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 Rate performance diagram of @N,SC@Na2WO4@PPy composite cathode material. Detailed Implementation

[0041] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but the present invention is not limited to the following embodiments.

[0042] Example 1

[0043] (1) Dissolve 11.82 mmol of Ni(NO3)2·6H2O, 1.18 mmol of Ni(CH3COO)2·4H2O, 11.82 mmol of Co(NO3)2·6H2O, 1.18 mmol of Co(CH3COO)2·4H2O, 49.1 mmol of Mn(NO3)2·6H2O, and 4.9 mmol of Mn(CH3COO)2·4H2O in 40 mL of deionized water and stir for 3 h to form a 2.0 mol / L salt solution;

[0044] (2) Add 40 mL of deionized water to the reaction flask and heat to 60 °C. Maintain the temperature at 60 °C under N2 atmosphere and stir. Use a peristaltic pump to continuously and slowly add 40 mL of saturated Na2CO3 solution and 40 mL of the salt solution from step (1) dropwise into the deionized water at a rate of 80 μL / min. At the same time, use a mixed solution of 15 mol / L ammonia and 6 mol / L NaOH with a volume ratio of 1.5:1 to adjust the pH of the reaction solution to 8.

[0045] (3) After all the salt solution and Na2CO3 solution in step (2) have been added dropwise, the pH is adjusted to 8.5 using a mixed solution of 15 mol / L ammonia water and 6 mol / L NaOH with a volume ratio of 1.5:1. After stirring at 60℃ for 12 h, the mixture is centrifuged at 3000 r / min at room temperature and washed with 1 mol / L hydrochloric acid to obtain the precipitate. The precipitate is then vacuum dried at 80℃ for 12 h to obtain the yellowish-brown precursor.

[0046] (4) The precursor from step (3) was mixed with 100 mmol of Li₂CO₃ and 20 mmol of Li₂F. The mixture was then transferred to a muffle furnace and pre-calcined at 500 °C for 4 h, followed by calcination in air at 900 °C for 16 h to obtain Li. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 Material;

[0047] (5) Take 0.1g of Li from step (4) 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 0.3g of medium-temperature coal tar pitch, 0.2g of ethylenediaminetetraacetic acid, 0.5g of thiourea, and 20mL of a mixture of acetone, ethylene glycol, and anhydrous ethanol in a volume ratio of 5:1:4 were added to a 50mL round-bottom flask. The mixture was ultrasonically dispersed for 1.5h and then magnetically stirred for 12h. The acetone, ethylene glycol, and anhydrous ethanol were removed by rotary evaporation to obtain the final mixture.

[0048] (6) The mixture from step (5) is heated to 400°C under a mixed gas of NH3 and N2 (with a volume ratio of 1:9), held at that temperature for 5 hours, and then cooled to room temperature in the furnace to obtain a lithium-rich manganese-based matrix oxide Li co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC materials, 0.98g of lithium-rich manganese-based layered oxide Li co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2@N,SC material, 0.02 g of Na2WO4 and 0.8 mL of pyrrole monomer were dissolved in 100 mL of deionized water and stirred at 80 °C for 5 h. After the deionized water was completely evaporated, the remaining mixture was vacuum dried at 80 °C for 24 h. After drying, a lithium-rich manganese-based layered oxide composite cathode material, Li, was obtained, consisting of nitrogen-sulfur-doped carbon co-coated polypyrrole (PPy) coated with sodium tungstate coated with lithium. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC@Na2WO4@PPy.

[0049] The resulting material is spherical, such as Figure 1 As shown, the rate performance diagram is as follows: Figure 2 As shown, the obtained product was used as the research electrode, and a lithium metal sheet was used as the counter electrode. A CR2016 coin cell lithium-ion battery was assembled in an argon-filled glove box and subjected to charge-discharge cycles at different current densities within a potential range of 2.0–4.8 V. At 0.1 C charge-discharge, the initial lithium intercalation capacity was 260.2 mAh / g, and the reversible lithium intercalation capacity after 200 cycles was 244.6 mAh / g, demonstrating excellent high-rate performance and cycle stability.

[0050] Example 2

[0051] (1) Dissolve 10 mmol of Ni(NO3)2·6H2O, 3 mmol of Ni(CH3COO)2·4H2O, 10 mmol of Co(NO3)2·6H2O, 3 mmol of Co(CH3COO)2·4H2O, 27 mmol of Mn(NO3)2·6H2O, and 27 mmol of Mn(CH3COO)2·4H2O in 40 mL of deionized water and stir for 2 h to form a 2.0 mol / L solution;

[0052] (2) Add 40 mL of deionized water to the reaction flask and heat to 60 °C. Maintain the temperature at 60 °C under N2 atmosphere and stir. Use a peristaltic pump to continuously and slowly add 50 mL of saturated Na2CO3 solution and 40 mL of the salt solution from step (1) dropwise into the above deionized water at a rate of 80 μL / min. At the same time, use a mixed solution of 13.5 mol / L ammonia water and 5 mol / L NaOH with a volume ratio of 1.7:1 to adjust the pH of the reaction solution to 7.8.

[0053] (3) After all the salt solution and Na2CO3 solution in step (2) have been added dropwise, the pH is adjusted to 8.5 using a mixed solution of 13.5 mol / L ammonia water and 5 mol / L NaOH with a volume ratio of 1.7:1. After stirring at 60℃ for 12 h, the mixture is centrifuged at 4000 r / min at room temperature and washed with 1.2 mol / L hydrochloric acid to obtain the precipitate. The precipitate is then vacuum dried at 80℃ for 12 h to obtain the yellowish-brown precursor.

[0054] (4) The precursor from step (3) was mixed with 100 mmol of Li₂CO₃ and 20 mmol of Li₂F. The mixture was then transferred to a muffle furnace and pre-calcined at 500 °C for 4 h, followed by calcination in air at 900 °C for 16 h to obtain Li. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 Material;

[0055] (5) Take 0.1g of Li from step (4) 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 0.3g of medium-temperature coal tar pitch, 0.3g of ethylenediaminetetraacetic acid, 0.4g of thiourea, and 20mL of a mixture of acetone, ethylene glycol, and anhydrous ethanol in a volume ratio of 5:1:4 were added to a 50mL round-bottom flask. The mixture was ultrasonically dispersed for 1 hour and then magnetically stirred for 12 hours. The acetone, ethylene glycol, and anhydrous ethanol were removed by rotary evaporation to obtain the final mixture.

[0056] (6) The mixture from step (5) was heated to 350°C under a mixed gas of NH3 and N2 (with a volume ratio of 1:9), held at that temperature for 4.5 h, and then cooled to room temperature in the furnace to obtain a lithium-rich manganese-based matrix oxide Li co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC materials, 0.9g of lithium-rich manganese-based layered oxide Li co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2@N,SC material, 0.1 g of Na2WO4 and 0.8 mL of pyrrole monomer were dissolved in 100 mL of deionized water and stirred at 80 °C for 3 h. After the deionized water was completely evaporated, the remaining mixture was vacuum dried at 60 °C for 24 h. After drying, a lithium-rich manganese-based layered oxide composite cathode material Li was obtained, consisting of nitrogen-sulfur-doped carbon co-coated polypyrrole (PPy) coated sodium tungstate coated. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC@Na2WO4@PPy.

[0057] The obtained material is spherical. Using the product as the research electrode and a lithium metal sheet as the counter electrode, a CR2016 coin cell lithium-ion battery was assembled in an argon-filled glove box and subjected to charge-discharge cycles at different current densities within a potential range of 2.0–4.8 V. At 0.1 C charge-discharge, the initial lithium intercalation capacity was 241.1 mAh / g, and the reversible lithium intercalation capacity after 200 cycles was 230.6 mAh / g, demonstrating excellent high-rate performance and cycle stability.

[0058] Example 3

[0059] (1) Dissolve 10 mmol of Ni(NO3)2·6H2O, 3 mmol of Ni(CH3COO)2·4H2O, 9 mmol of Co(NO3)2·6H2O, 4 mmol of Co(CH3COO)2·4H2O, 27 mmol of Mn(NO3)2·6H2O, and 27 mmol of Mn(CH3COO)2·4H2O in 40 mL of deionized water and stir for 2.5 h to form a 2.0 mol / L salt solution;

[0060] (2) Add 40 mL of deionized water to the reaction flask and heat to 65 °C. Maintain the temperature at 65 °C under N2 atmosphere and stir. Use a peristaltic pump to continuously and slowly add 55 mL of saturated Na2CO3 solution and 40 mL of the salt solution from step (1) dropwise into the above deionized water at a rate of 85 μL / min. At the same time, use a mixed solution of 14 mol / L ammonia water and 6.5 mol / L NaOH with a volume ratio of 1.8:1 to adjust the pH of the reaction solution to 8.

[0061] (3) After all the salt solution and Na2CO3 solution in step (2) have been added dropwise, the pH is adjusted to 8.5 using a mixed solution of 15 mol / L ammonia and 6 mol / L NaOH with a volume ratio of 1.8:1. After stirring at 65℃ for 12 h, the mixture is centrifuged at 3500 r / min at room temperature and washed with 1.3 mol / L hydrochloric acid to obtain the precipitate. The precipitate is then vacuum dried at 80℃ for 12 h to obtain the yellowish-brown precursor.

[0062] (4) The precursor from step (3) was mixed with 108 mmol of Li₂CO₃ and 20 mmol of Li₂F. The mixture was then transferred to a muffle furnace and pre-calcined at 520 °C for 3.8 h, followed by calcination in air at 920 °C for 15.5 h to obtain Li. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 Material;

[0063] (5) Take 0.1g of Li from step (4) 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 0.3g of medium-temperature coal tar pitch, 0.3g of ethylenediaminetetraacetic acid, 0.4g of thiourea, and 20mL of a mixture of acetone, ethylene glycol, and anhydrous ethanol in a volume ratio of 5:1:4 were added to a 50mL round-bottom flask. The mixture was ultrasonically dispersed for 2 hours and then magnetically stirred for 14 hours. The acetone, ethylene glycol, and anhydrous ethanol were removed by rotary evaporation to obtain the final mixture.

[0064] (6) The above mixture was heated to 380°C under a mixed gas of NH3 and N2 (with a volume ratio of 1:9), held at that temperature for 4.7 h, and then cooled to room temperature in the furnace to obtain a lithium-rich manganese-based matrix oxide Li co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC materials, using 0.95g of lithium-rich manganese-based layered oxide Li co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2@N,SC material, 0.05 g of Na2WO4 and 0.8 mL of pyrrole monomer were dissolved in 100 mL of deionized water and stirred at 85 °C for 4 h. After the deionized water was completely evaporated, the remaining mixture was vacuum dried at 70 °C for 25 h. After drying, a lithium-rich manganese-based layered oxide composite cathode material Li was obtained, consisting of nitrogen-sulfur-doped carbon co-coated polypyrrole (PPy) coated with sodium tungstate coated with lithium. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC@Na2WO4@PPy.

[0065] The obtained material is spherical. Using the product as the research electrode and a lithium metal sheet as the counter electrode, a CR2016 coin cell lithium-ion battery was assembled in an argon-filled glove box and subjected to charge-discharge cycles at different current densities within a potential range of 2.0–4.8 V. At 0.1 C charge-discharge, the initial lithium intercalation capacity was 225.6 mAh / g, and the reversible lithium intercalation capacity after 200 cycles was 216.8 mAh / g, demonstrating excellent high-rate performance and cycle stability.

[0066] Example 4

[0067] (1) Dissolve 8.67 mmol of Ni(NO3)2·6H2O, 4.33 mmol of Ni(CH3COO)2·4H2O, 8.67 mmol of Co(NO3)2·6H2O, 4.33 mmol of Co(CH3COO)2·4H2O, 36 mmol of Mn(NO3)2·6H2O, and 18 mmol of Mn(CH3COO)2·4H2O in 40 mL of deionized water and stir for 3 h to form a 2.0 mol / L salt solution;

[0068] (2) Add 40 mL of deionized water to the reaction flask and heat to 70 °C. Maintain the temperature at 70 °C under N2 atmosphere and stir. Use a peristaltic pump to continuously and slowly add 45 mL of saturated Na2CO3 solution and 40 mL of the salt solution from step (1) dropwise at a rate of 80 μL / min to the above deionized water. At the same time, use a mixed solution of 15 mol / L ammonia water and 6 mol / L NaOH with a volume ratio of 1.6:1 to adjust the pH of the reaction solution to 8.1.

[0069] (3) After all the salt solution and Na2CO3 solution in step (2) have been added dropwise, the pH is adjusted to 8.5 using a mixed solution of 15 mol / L ammonia water and 6 mol / L NaOH with a volume ratio of 1.6:1. After stirring at 70℃ for 14 h, the mixture is centrifuged at 4000 r / min at room temperature and washed with 1.1 mol / L hydrochloric acid to obtain the precipitate. The precipitate is then vacuum dried at 83℃ for 13 h to obtain the yellowish-brown precursor.

[0070] (4) The precursor from step (3) was mixed with 100 mmol of Li₂CO₃ and 20 mmol of Li₂F. The mixture was then transferred to a muffle furnace and pre-calcined at 510 °C for 3.8 h, followed by calcination in air at 910 °C for 15.8 h to obtain Li. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 Material;

[0071] (5) Take 0.1g of Li from step (4) 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 0.3g of medium-temperature coal tar pitch, 0.3g of ethylenediaminetetraacetic acid, 0.4g of thiourea, and 20mL of a mixture of acetone, ethylene glycol, and anhydrous ethanol in a volume ratio of 5:1:4 were added to a 50mL round-bottom flask. The mixture was ultrasonically dispersed for 1.7h and then magnetically stirred for 13h. The acetone, ethylene glycol, and anhydrous ethanol were removed by rotary evaporation to obtain the final mixture.

[0072] (6) The mixture from step (5) was heated to 400°C under a mixed gas of NH3 and N2 (with a volume ratio of 1:9), held at that temperature for 4.8 h, and then cooled to room temperature in the furnace to obtain a lithium-rich manganese-based matrix oxide Li co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC materials, 0.96g of lithium-rich manganese-based layered oxide Li co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2@N,SC material, 0.04 g of Na2WO4 and 0.8 mL of pyrrole monomer were dissolved in 100 mL of deionized water and stirred at 83 °C for 4.5 h. After the deionized water was completely evaporated, the remaining mixture was vacuum dried at 75 °C for 26 h. After drying, a lithium-rich manganese-based layered oxide composite cathode material, Li, was obtained, consisting of nitrogen-sulfur-doped carbon co-coated polypyrrole (PPy) coated sodium tungstate coated. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC@Na2WO4@PPy.

[0073] The obtained material is spherical. Using the product as the research electrode and a lithium metal sheet as the counter electrode, a CR2016 coin cell lithium-ion battery was assembled in an argon-filled glove box and subjected to charge-discharge cycles at different current densities within a potential range of 2.0–4.8 V. At 0.1 C charge-discharge, the initial lithium intercalation capacity was 230.5 mAh / g, and the reversible lithium intercalation capacity after 200 cycles was 219.9 mAh / g, demonstrating excellent high-rate performance and cycle stability.

[0074] Example 5

[0075] (1) Dissolve 10 mmol of Ni(NO3)2·6H2O, 3 mmol of Ni(CH3COO)2·4H2O, 9 mmol of Co(NO3)2·6H2O, 4 mmol of Co(CH3COO)2·4H2O, 27 mmol of Mn(NO3)2·6H2O, and 27 mmol of Mn(CH3COO)2·4H2O in 40 mL of deionized water and stir for 2.8 h to form a 2.0 mol / L salt solution;

[0076] (2) Add 40 mL of deionized water to the reaction flask and heat to 65 °C. Maintain the temperature at 65 °C under N2 atmosphere and stir. Use a peristaltic pump to continuously and slowly add 45 mL of saturated Na2CO3 solution and 40 mL of the salt solution from step (1) dropwise into the above deionized water at a rate of 87 μL / min. At the same time, use a mixed solution of 14 mol / L ammonia water and 7 mol / L NaOH with a volume ratio of 1.9:1 to adjust the pH of the reaction solution to 7.9.

[0077] (3) After all the salt solution and Na2CO3 solution in step (2) have been added dropwise, the pH is adjusted to 8.5 using a mixed solution of 14 mol / L ammonia water and 7 mol / L NaOH with a volume ratio of 1.9:1. After stirring at 65℃ for 14 h, the mixture is centrifuged at 3800 r / min at room temperature and washed with 1.6 mol / L hydrochloric acid to obtain the precipitate. The precipitate is then vacuum dried at 85℃ for 15 h to obtain the yellowish-brown precursor.

[0078] (4) The precursor from step (3) was mixed with 121 mmol of Li₂CO₃ and 23 mmol of Li₂F. The mixture was then transferred to a muffle furnace and pre-calcined at 500 °C for 4 h, followed by calcination in air at 900 °C for 6 h to obtain Li. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 Material;

[0079] (5) Take 0.1g of Li from step (4) 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 0.3g of medium-temperature coal tar pitch, 0.3g of ethylenediaminetetraacetic acid, 0.4g of thiourea, and 20mL of a mixture of acetone, ethylene glycol, and anhydrous ethanol in a volume ratio of 5:1:4 were added to a 50mL round-bottom flask. The mixture was ultrasonically dispersed for 2 hours and then magnetically stirred for 12 hours. The acetone, ethylene glycol, and anhydrous ethanol were removed by rotary evaporation to obtain the final mixture.

[0080] (6) The mixture from step (5) is heated to 450°C under a mixed gas of NH3 and N2 (with a volume ratio of 1:9), held at that temperature for 5 hours, and then cooled to room temperature in the furnace to obtain a lithium-rich manganese-based matrix oxide Li co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC materials, 0.94g of lithium-rich manganese-based layered oxide Li co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2@N,SC material, 0.06 g of Na2WO4 and 0.8 mL of pyrrole monomer were dissolved in 100 mL of deionized water and stirred at 84 °C for 4 h. After the deionized water was completely evaporated, the remaining mixture was vacuum dried at 74 °C for 24 h. After drying, a lithium-rich manganese-based layered oxide composite cathode material, Li, was obtained, consisting of nitrogen-sulfur-doped carbon co-coated polypyrrole (PPy) coated with sodium tungstate coated with lithium. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC@Na2WO4@PPy.

[0081] The obtained material is spherical. Using the product as the research electrode and a lithium metal sheet as the counter electrode, a CR2016 coin cell lithium-ion battery was assembled in an argon-filled glove box and subjected to charge-discharge cycles at different current densities within a potential range of 2.0–4.8 V. At 0.1 C charge-discharge, the initial lithium insertion capacity was 212.6 mAh / g, and the reversible lithium extraction capacity after 200 cycles was 206.5 mAh / g, demonstrating excellent high-rate performance and cycle stability.

[0082] Example 6

[0083] (1) Dissolve 10 mmol of Ni(NO3)2·6H2O, 3 mmol of Ni(CH3COO)2·4H2O, 9 mmol of Co(NO3)2·6H2O, 4 mmol of Co(CH3COO)2·4H2O, 27 mmol of Mn(NO3)2·6H2O, and 27 mmol of Mn(CH3COO)2·4H2O in 40 mL of deionized water and stir for 2.6 h to form a 2.0 mol / L salt solution;

[0084] (2) Add 40 mL of deionized water to the reaction flask and heat to 68 °C. Maintain the temperature at 68 °C under N2 atmosphere and stir. Use a peristaltic pump to continuously and slowly add 55 mL of saturated Na2CO3 solution and 40 mL of the salt solution from step (1) dropwise into the deionized water at a rate of 85 μL / min. At the same time, use a mixed solution of 15 mol / L ammonia and 6.5 mol / L NaOH with a volume ratio of 1.8:1 to adjust the pH of the reaction solution to 8.

[0085] (3) After all the salt solution and Na2CO3 solution in step (2) have been added dropwise, the pH is adjusted to 8.5 using a mixed solution of 15 mol / L ammonia water and 6.5 mol / L NaOH with a volume ratio of 1.8:1. After stirring at 68℃ for 14.5 h, the mixture is centrifuged at 4100 r / min at room temperature and washed with 1.2 mol / L hydrochloric acid to obtain the precipitate. The precipitate is then vacuum dried at 82℃ for 14 h to obtain the yellowish-brown precursor.

[0086] (4) The precursor from step (3) was mixed with 120.5 mmol of Li₂CO₃ and 23.5 mmol of Li₂F. The mixture was then transferred to a muffle furnace and pre-calcined at 540 °C for 4 h, followed by calcination in air at 940 °C for 6 h to obtain Li. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 Material;

[0087] (5) Take 0.1g of Li from step (4) 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 0.3g of medium-temperature coal tar pitch, 0.3g of ethylenediaminetetraacetic acid, 0.4g of thiourea, and 20mL of a mixture of acetone, ethylene glycol, and anhydrous ethanol in a volume ratio of 5:1:4 were added to a 50mL round-bottom flask. The mixture was ultrasonically dispersed for 1.8h and then magnetically stirred for 14h. The acetone, ethylene glycol, and anhydrous ethanol were removed by rotary evaporation to obtain the final mixture.

[0088] (6) The mixture from step (5) was heated to 440°C under a mixed gas of NH3 and N2 (with a volume ratio of 1:9), held at that temperature for 4.8 h, and then cooled to room temperature in the furnace to obtain a lithium-rich manganese-based matrix oxide Li co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC materials, 0.92g of lithium-rich manganese-based layered oxide Li co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2@N,SC material, 0.08 g of Na2WO4 and 0.8 mL of pyrrole monomer were dissolved in 100 mL of deionized water and stirred at 80 °C for 5 h. After the deionized water was completely evaporated, the remaining mixture was vacuum dried at 70 °C for 25 h. After drying, a lithium-rich manganese-based layered oxide composite cathode material, Li, was obtained, consisting of nitrogen-sulfur-doped carbon co-coated polypyrrole (PPy) coated with sodium tungstate coated with lithium. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC@Na2WO4@PPy.

[0089] The obtained material is spherical. Using the product as the research electrode and a lithium metal sheet as the counter electrode, a CR2016 coin cell lithium-ion battery was assembled in an argon-filled glove box and subjected to charge-discharge cycles at different current densities within a potential range of 2.0–4.8 V. At 0.1 C charge-discharge, the initial lithium intercalation capacity was 220.6 mAh / g, and the reversible lithium intercalation capacity after 200 cycles was 207.9 mAh / g, demonstrating excellent high-rate performance and cycle stability.

[0090] Example 7

[0091] (1) Dissolve 10 mmol of Ni(NO3)2·6H2O, 3 mmol of Ni(CH3COO)2·4H2O, 9 mmol of Co(NO3)2·6H2O, 4 mmol of Co(CH3COO)2·4H2O, 27 mmol of Mn(NO3)2·6H2O, and 27 mmol of Mn(CH3COO)2·4H2O in 40 mL of deionized water and stir for 2.5 h to form a 2.0 mol / L salt solution;

[0092] (2) Add 40 mL of deionized water to the reaction flask and heat to 68 °C. Maintain the temperature at 68 °C under N2 atmosphere and stir. Use a peristaltic pump to continuously and slowly add 54 mL of saturated Na2CO3 solution and 40 mL of the salt solution from step (1) dropwise into the above deionized water at a rate of 85 μL / min. At the same time, use a mixed solution of 15 mol / L ammonia water and 6.5 mol / L NaOH with a volume ratio of 1.7:1 to adjust the pH of the reaction solution to 8.

[0093] (3) After all the salt solution and Na2CO3 solution in step (2) have been added dropwise, the pH is adjusted to 8.5 using a mixed solution of 15 mol / L ammonia water and 6.5 mol / L NaOH with a volume ratio of 1.7:1. After stirring at 68℃ for 14 h, the mixture is centrifuged at 4200 r / min at room temperature and washed with 1.2 mol / L hydrochloric acid to obtain the precipitate. The precipitate is then vacuum dried at 82℃ for 14 h to obtain the yellowish-brown precursor.

[0094] (4) The precursor from step (3) was mixed with 121 mmol of Li₂CO₃ and 23 mmol of Li₂F. The mixture was then transferred to a muffle furnace and pre-calcined at 550 °C for 4 h, followed by calcination in air at 950 °C for 6 h to obtain Li. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 Material;

[0095] (5) Take 0.1g of Li from step (4) 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 0.3g of medium-temperature coal tar pitch, 0.2g of ethylenediaminetetraacetic acid, 0.5g of thiourea, and 20mL of a mixture of acetone, ethylene glycol, and anhydrous ethanol in a volume ratio of 5:1:4 were added to a 50mL round-bottom flask. The mixture was ultrasonically dispersed for 1.5h and then magnetically stirred for 14h. The acetone, ethylene glycol, and anhydrous ethanol were removed by rotary evaporation to obtain the final mixture.

[0096] (6) The mixture from step (5) was heated to 440°C under a mixed gas of NH3 and N2 (with a volume ratio of 1:9), held at that temperature for 4.8 h, and then cooled to room temperature in the furnace to obtain a lithium-rich manganese-based matrix oxide Li co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC materials, 0.92g of lithium-rich manganese-based layered oxide Li co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2@N,SC material, 0.08 g of Na2WO4 and 0.8 mL of pyrrole monomer were dissolved in 100 mL of deionized water and stirred at 80 °C for 5 h. After the deionized water was completely evaporated, the remaining mixture was vacuum dried at 70 °C for 25 h. After drying, a lithium-rich manganese-based layered oxide composite cathode material, Li, was obtained, consisting of nitrogen-sulfur-doped carbon co-coated polypyrrole (PPy) coated with sodium tungstate coated with lithium. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC@Na2WO4@PPy.

[0097] The obtained material is spherical. Using the product as the research electrode and a lithium metal sheet as the counter electrode, a CR2016 coin cell lithium-ion battery was assembled in an argon-filled glove box and subjected to charge-discharge cycles at different current densities within a potential range of 2.0–4.8 V. At 0.1 C charge-discharge, the initial lithium intercalation capacity was 218.7 mAh / g, and the reversible lithium intercalation capacity after 200 cycles was 201.4 mAh / g, demonstrating excellent high-rate performance and cycle stability.

[0098] Example 8

[0099] (1) Dissolve 6.5 mmol of Ni(NO3)2·6H2O, 6.5 mmol of Ni(CH3COO)2·4H2O, 6.5 mmol of Co(NO3)2·6H2O, 6.5 mmol of Co(CH3COO)2·4H2O, 27 mmol of Mn(NO3)2·6H2O, and 27 mmol of Mn(CH3COO)2·4H2O in 40 mL of deionized water and stir for 3 h to form a 2.0 mol / L salt solution;

[0100] (2) Add 40 mL of deionized water to the reaction flask and heat to 70 °C. Maintain the temperature at 70 °C under N2 atmosphere and stir. Use a peristaltic pump to continuously and slowly add 60 mL of saturated Na2CO3 solution and 40 mL of the salt solution from step (1) dropwise at a rate of 90 μL / min to the above deionized water. At the same time, use a mixed solution of 15 mol / L ammonia water and 7 mol / L NaOH with a volume ratio of 2:1 to adjust the pH of the reaction solution to 8.2.

[0101] (3) After all the salt solution and Na2CO3 solution in step (2) have been added dropwise, the pH is adjusted to 8.5 using a mixed solution of 15 mol / L ammonia and 7 mol / L NaOH in a volume ratio of 2:1. After stirring at 70℃ for 15 h, the mixture is centrifuged at 5000 r / min at room temperature and washed with 1.5 mol / L hydrochloric acid to obtain the precipitate. The precipitate is then vacuum dried at 85℃ for 15 h to obtain the yellowish-brown precursor.

[0102] (4) The precursor from step (3) was mixed with 121.5 mmol of Li₂CO₃ and 22.5 mmol of Li₂F. The mixture was then transferred to a muffle furnace and pre-calcined at 550 °C for 4 h, followed by calcination in air at 950 °C for 16 h to obtain Li. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 Material;

[0103] (5) Take 0.1g of Li from step (4) 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 0.3g of medium-temperature coal tar pitch, 0.3g of ethylenediaminetetraacetic acid, 0.4g of thiourea, and 20mL of a mixture of acetone, ethylene glycol, and anhydrous ethanol in a volume ratio of 5:1:4 were added to a 50mL round-bottom flask. The mixture was ultrasonically dispersed for 2 hours and then magnetically stirred for 15 hours. The acetone, ethylene glycol, and anhydrous ethanol were removed by rotary evaporation to obtain the final mixture.

[0104] (6) The mixture from step (5) is heated to 450°C under a mixed gas of NH3 and N2 (with a volume ratio of 1:9), held at that temperature for 5 hours, and then cooled to room temperature in the furnace to obtain a lithium-rich manganese-based matrix oxide Li co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC materials, 0.99g of lithium-rich manganese-based layered oxide Li co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2@N,SC material, 0.01 g of Na2WO4 and 0.8 mL of pyrrole monomer were dissolved in 100 mL of deionized water and stirred at 85 °C for 5 h. After the deionized water was completely evaporated, the remaining mixture was vacuum dried at 80 °C for 26 h. After drying, a lithium-rich manganese-based layered oxide composite cathode material, Li, was obtained, consisting of nitrogen-sulfur-doped carbon co-coated polypyrrole (PPy) coated with sodium tungstate coated with pyrrole. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC@Na2WO4@PPy.

[0105] The obtained material is spherical. Using the product as the research electrode and a lithium metal sheet as the counter electrode, a CR2016 coin cell lithium-ion battery was assembled in an argon-filled glove box and subjected to charge-discharge cycles at different current densities within a potential range of 2.0–4.8 V. At 0.1 C charge-discharge, the initial lithium intercalation capacity was 229.4 mAh / g, and the reversible lithium intercalation capacity after 200 cycles was 218.3 mAh / g, demonstrating excellent high-rate performance and cycle stability.

Claims

1. A lithium-rich manganese-based layered oxide composite cathode material, characterized in that, The lithium-rich manganese-based layered oxide composite cathode material is coated with polypyrrole (PPy) through nitrogen-sulfur doping and carbon co-coating, with the structural formula: Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC@Na2WO4@PPy, the Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC@Na2WO4@PPy is obtained through Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 Heating the material with a carbon source under a mixed atmosphere of NH3 and N2 yields a lithium-rich manganese-based matrix oxide, Li, co-coated with nitrogen and sulfur doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 The @N,SC material is prepared by heating a mixture of medium-temperature coal tar pitch, ethylenediaminetetraacetic acid, and thiourea with Na2WO4 and PPy monomer in water using the carbon source.

2. A method for preparing the lithium-rich manganese-based layered oxide composite cathode material according to claim 1, characterized in that, Includes the following steps: (1) Dissolve the nickel source, cobalt source and manganese source in deionized water and stir to obtain a salt solution; (2) Heat the deionized water; then, under stirring, slowly add the saturated Na2CO3 solution and the salt solution from step 1 into the above deionized water, and adjust the pH of the resulting reaction solution with an alkaline substance. (3) After all the salt solution and Na2CO3 solution in step 2 have been added, continue to add alkaline substances to adjust the pH, then stir, centrifuge and wash to obtain the precipitate; vacuum dry the precipitate to obtain the precursor; (4) The precursor from step 3 is mixed with lithium salt, and the resulting mixture is then pre-calcined; then calcined in air to obtain Li. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 Materials; the lithium salt is a mixture of Li₂CO₃ and Li₂F; (5) Take Li from step 4 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 The material and carbon source are mixed with an organic solvent, ultrasonically dispersed, then stirred, and the organic solvent is removed by rotary evaporation to obtain a mixture; the carbon source is a mixture of medium-temperature coal tar pitch, ethylenediaminetetraacetic acid, and thiourea; (6) The mixture from step 5 is heated under a mixed atmosphere and cooled to room temperature to obtain a lithium-rich manganese-based matrix oxide Li co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC material, wherein the mixed atmosphere is a mixture of NH3 and N2 gas; 0.9~1g of lithium-rich manganese-based layered oxide Li co-coated with nitrogen-sulfur-doped carbon. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC material, 0.01~0.1g Na2WO4 and 0.8 mL pyrrole monomer were dissolved in 100 mL deionized water, heated and stirred to obtain a residual mixture, which was then vacuum dried to obtain a lithium-rich manganese-based layered oxide composite cathode material Li co-coated with nitrogen-sulfur-doped carbon polypyrrole (PPy). 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 @N,SC@Na2WO4@PPy.

3. The method for preparing the lithium-rich manganese-based layered oxide composite cathode material according to claim 2, characterized in that, In step (1), the nickel source is a mixture of Ni(NO3)2·6H2O and Ni(CH3COO)2·4H2O, with a molar ratio of 10:(1-10); the cobalt source is a mixture of Co(NO3)2·6H2O and Co(CH3COO)2·4H2O, with a molar ratio of 10:(1-10). The molar ratio of Mn(NO3)2·6H2O to Mn(CH3COO)2·4H2O is 10:(1-10); the manganese source is a mixture of Mn(NO3)2·6H2O and Mn(CH3COO)2·4H2O, with a molar ratio of Mn(NO3)2·6H2O to Mn(CH3COO)2·4H2O of 10:(1-10); the molar ratio of the nickel source, cobalt source, and manganese source is 13:13:54; the stirring time is 2-3 hours; and the concentration of the salt solution is 2.0 mol·L⁻¹. -1 .

4. The method for preparing the lithium-rich manganese-based layered oxide composite cathode material according to claim 2, characterized in that, In step (2), the heating is performed by adding deionized water to the reaction flask and heating it to 60-70°C; the stirring is performed by using a magnetic stirrer to maintain the temperature at 60-70°C under an inert atmosphere, wherein the inert atmosphere is N2; the volume ratio of the deionized water, the salt solution from step 1, and the saturated Na2CO3 solution is 1:1:(1-1.5); the slow dripping is performed by using a peristaltic pump at a rate of 80-90 μL / min; the alkaline substance is a mixed solution of 13.5-15 mol / L ammonia water and 5-7 mol / L NaOH, wherein the volume ratio of the alkaline substance to the ammonia water is (1.5-2):1; and the pH value is adjusted to 7.8-8.

2.

5. The method for preparing the lithium-rich manganese-based layered oxide composite cathode material according to claim 2, characterized in that, In step (3), the pH is adjusted to 8.5; the stirring is carried out at 60-70℃ for 12-15 hours; the washing is carried out with hydrochloric acid at a concentration of 1-1.5 mol / L; the centrifugation is carried out at room temperature at a speed of 3000-5000 r / min; the vacuum drying temperature is 80-85℃ and the drying time is 12-15 hours.

6. The method for preparing the lithium-rich manganese-based layered oxide composite cathode material according to claim 2, characterized in that, In step (4), the molar ratio of Li2CO3 to Li2F is (5~5.4):1; the lithium salt and the precursor are mixed according to the molar ratio of Li:(Ni+Co+Mn) of (3~3.6):2; the pre-calcination is to transfer the mixture into a muffle furnace, the pre-calcination temperature is 500~550℃, and the pre-calcination time is 3.5~4h; the calcination temperature is 900~950℃, and the calcination time is 15~16h.

7. The method for preparing the lithium-rich manganese-based layered oxide composite cathode material according to claim 2, characterized in that, In step (5), the mass ratio of medium-temperature coal tar pitch, ethylenediaminetetraacetic acid, and thiourea is 3:(2-3):(4-5); the organic solvent is a mixture of acetone, ethylene glycol, and anhydrous ethanol, with a volume ratio of acetone, ethylene glycol, and anhydrous ethanol of 5:1:4; the Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 1.8 F 0.2 The mass ratio of material to carbon source is 1:10; the volume mass ratio of organic solvent to carbon source (mL:g) is 20:1; the ultrasonic dispersion time is 1~2h; the stirring is performed by strong magnetic stirring for 12~15h.

8. The method for preparing the lithium-rich manganese-based layered oxide composite cathode material according to claim 2, characterized in that, In step (6), the volume ratio of NH3 to N2 is 1:9; the heating is to raise the temperature to 350~450℃ and keep it at that temperature for 4.5~5h; the heating and stirring is to stir at 80~85℃ for 3~5h; the vacuum drying is to dry at 60~80℃ for 24~26h.

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