A low-alkaline high-lattice-stability coated modified positive electrode material, a preparation method and application thereof

Abstract

The application provides a low-alkaline high-lattice-stability coated modified positive electrode material and a preparation method and application thereof. The coated modified positive electrode material has a core-shell structure, comprises a coated substrate and a composite coating layer, and the composite coating layer contains phosphorus elements and tungsten elements; wherein the composite coating layer is prepared by in-situ thickness-controllable coating on the surface of the coated substrate; the coated modified positive electrode material has low alkalinity and high lattice stability; and the composite coating layer is uniform, continuous, complete and thickness-controllable. The coated modified positive electrode material has more stable interface structure and excellent electrochemical performance.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery cathode material technology, specifically relating to a low-alkalinity, high-lattice-stability coated modified cathode material, its preparation method, and its application. Background Technology

[0002] With the rapid development of the new energy field, lithium-ion batteries are playing an increasingly important role due to their high energy density, long cycle life, and increasingly mature manufacturing processes. Especially with the growing popularity of electric vehicles, higher demands are being placed on the performance of lithium-ion batteries. Among these, the cathode material, as one of the most critical components of a lithium-ion battery, directly affects the energy density, cycle life, and safety stability of the finished battery. Currently, the main bottleneck in improving battery energy lies in the capacity and voltage limitations of the cathode electrode material. While the use of higher-capacity high-nickel ternary cathode materials has improved energy density, it has also brought more serious safety hazards. Furthermore, the high alkalinity of high-nickel materials places strict requirements on the electrode processing technology, especially the control of moisture in the working environment, which undoubtedly increases the material preparation cost. High-nickel materials undergo a series of phase transitions during charging, from hexagonal phase H1 to monoclinic phase M, then to hexagonal phase H2, and finally to hexagonal phase H3. Their lattice stability is poor, and irreversible phase transitions are the main factors causing the materials to deactivate during charging and discharging. They are also the source of a series of subsequent macroscopic changes in the materials, which greatly limits the large-scale use of such materials.

[0003] Common methods for improving the stability of electrode materials include coating and doping, which modify and control the material at the surface and interface as well as the bulk phase. A suitable surface coating can significantly improve the stability of the electrode material at the electrolyte interface, reduce side reactions, suppress the corrosion of the electrode material by HF generated from electrolyte decomposition, increase the stability of the electrode material's surface structure, reduce irreversible phase transitions, suppress lattice oxygen loss under high voltage, reduce gas generation, and improve the material's thermal stability, thereby significantly improving the cycle life and safety of the electrode material. Furthermore, a suitable surface coating can also reduce interfacial resistance, promote charge transfer, and improve the material's rate performance. Phosphate has been extensively documented as an effective surface coating for cathode materials; the commonly used method is to apply metal ions (M... n + ), phosphate (PO4) 3-Other methods involve directly mixing and grinding or evaporating the cathode material to achieve partial surface coating through adsorption between particles. However, this method often struggles to achieve uniform and controllable coating, and the intended coating effect is significantly reduced due to the unevenness, incompleteness, and uncontrollability of the coating layer. A few studies have achieved uniform phosphate coating, such as patent documents CN105322158A and CN107706389A. These methods are based on controlling the precipitation rate of metal phosphates in solution, achieving uniform and controllable coating on the electrode material surface. Adjusting the coating layer thickness allows for precise control of the material's electrochemical performance. However, in these preparation processes, precipitants are typically introduced to control the precipitation rate of metal phosphates. Summary of the Invention

[0004] The purpose of this invention is to provide a low-alkalinity, high-lattice-stability coated modified cathode material, its preparation method, and its application.

[0005] This invention provides a coated modified cathode material having a core-shell structure, comprising a coating substrate and a composite coating layer, wherein the composite coating layer contains phosphorus and tungsten elements; wherein the composite coating layer is prepared by in-situ coating with controllable thickness on the surface of the coating substrate. Preferably, the coated modified cathode material has low alkalinity and high lattice stability. Preferably, the composite coating layer is uniform, continuous, intact, and has controllable thickness.

[0006] Preferably, the surface pH value of the coated modified cathode material is less than 11, more preferably less than 10.5, and even more preferably less than 10.5 and greater than 10.

[0007] According to an embodiment of the present invention, the substrate to be coated is selected from a ternary cathode material with high surface alkalinity. Preferably, the surface pH value of the ternary cathode material is greater than 11, and more preferably greater than 12.

[0008] Preferably, the chemical formula of the ternary cathode material is as follows: LiNi x Co y Mn z O2, where x+y+z=1, x≥0.6, and x is preferably greater than or equal to 0.6 and less than or equal to 0.9.

[0009] For example, the ternary material is selected from LiNi. 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.7 Co 0.15 Mn 0.15 O2, LiNi 0.8 Co 0.1 Mn 0.1O2 or LiNi 0.83 Co 0.07 Mn 0.1 O2.

[0010] Preferably, the ternary cathode material is selected from secondary spherical particles or single crystal particles, and more preferably single crystal particles.

[0011] According to an embodiment of the present invention, the tungsten content in the composite coating layer is 40-70 wt%, preferably 50-60 wt%.

[0012] According to an embodiment of the present invention, the phosphorus content in the composite coating layer is 1-10 wt%, preferably 5-10 wt%, for example 6.69 wt%, 7.57 wt%, 8.24 wt%, and 8.91 wt%.

[0013] According to an embodiment of the present invention, the thickness of the composite coating layer is 1-200 nm, preferably 5-50 nm, more preferably 8-40 nm, for example 8 nm, 9 nm, 10 nm, 12 nm, 17 nm, 25 nm, or 33 nm.

[0014] According to an embodiment of the present invention, the high lattice stability of the coated modified cathode material means that its surface lattice remains intact after 150 charge-discharge cycles.

[0015] This invention also provides a method for preparing the above-mentioned coated modified cathode material, the method comprising:

[0016] 1) Preparation of solution A: Dissolve the coated substrate and tungsten salt in a solvent to obtain solution A; Preparation of solution B: Dissolve the phosphorus-containing precipitant in a solvent to obtain solution B;

[0017] 2) Under stirring conditions, solution B is added to solution A. The phosphorus-containing precipitant and tungsten element are co-precipitated through coordination, forming an intermediate coating layer in situ on the surface of the coated substrate particles, thus obtaining an intermediate product with a coated core-shell structure.

[0018] 3) The intermediate product obtained in step 2) is calcined to obtain the coated modified cathode material.

[0019] According to an embodiment of the present invention, in solution A, the solvent is selected from at least one of water, methanol, ethanol, ethylene glycol, propanol, isopropanol, propylene glycol, n-butanol, acetonitrile, or acetone, preferably ethanol.

[0020] According to an embodiment of the present invention, solution B uses the same or different solvent as solution A, preferably the same solvent as solution A.

[0021] According to an embodiment of the present invention, in solution A, the coating substrate has the meaning described above.

[0022] Preferably, the concentration of the coated substrate is 0.1–150 g / L, more preferably 1–50 g / L, and even more preferably 5–20 g / L, for example 8 g / L, 13 g / L, or 16 g / L.

[0023] According to an embodiment of the present invention, in solution A, the tungsten salt is selected from at least one of tungsten chloride, sulfate, nitrate, acetate and alkoxide.

[0024] Preferably, the concentration of the tungsten salt is 0.001 to 0.1 mol / L, more preferably 0.001 to 0.005 mol / L, for example 0.0013 mol / L.

[0025] According to an embodiment of the present invention, in solution B, the phosphorus-containing precipitant is selected from phytic acid.

[0026] Preferably, the concentration of the phosphorus-containing precipitant is 0.0005 to 0.05 mol / L, and more preferably, for example, 0.0006 mol / L.

[0027] According to an embodiment of the present invention, in step 2), the molar ratio of the phosphorus-containing precipitant to the metal element is 1:(1-5), for example, 1:3.

[0028] According to an embodiment of the present invention, in step 2), solution B is slowly added to solution A by a peristaltic pump, for example, the speed of the peristaltic pump is 1 mL / min.

[0029] According to an embodiment of the present invention, in step 2), the reaction temperature is 10–100°C and the reaction time is 1–48 h. Preferably, the reaction temperature is 25–40°C and the reaction time is 1–10 h. Exemplarily, the reaction temperature is 25°C and the reaction time is 5 h.

[0030] According to an embodiment of the present invention, in step 3), the calcination is carried out in an oxygen-containing atmosphere. Preferably, the oxygen-containing atmosphere is selected from at least one of air or oxygen. The present invention does not specifically limit the oxygen-containing atmosphere used during calcination; it can be carried out in an oxygen-containing atmosphere commonly used by those skilled in the art.

[0031] According to an embodiment of the present invention, in step 3), the calcination temperature is 400–900°C, and the calcination time is 1–10 h. Preferably, the calcination temperature is 600–800°C, and the calcination time is 1–5 h. Exemplarily, the calcination temperature is 700°C, and the calcination time is 3 h.

[0032] The present invention also provides an application of the above-mentioned coated modified cathode material in high-energy lithium storage devices.

[0033] Beneficial effects

[0034] This invention provides a low-alkalinity, high-lattice-stability coated modified cathode material, which can reduce the alkalinity of the cathode material, thereby reducing the requirements for environmental moisture control during the preparation of lithium-ion batteries. This invention achieves uniform construction of a composite coating layer containing phosphorus and tungsten on the surface of the substrate through indirect coating, achieving full coverage of the substrate surface and providing better protection.

[0035] The coated modified cathode material of the present invention can effectively reduce the alkalinity of the coated substrate by consuming the residual alkali on the surface of the coated substrate through the phosphorus element in the composite coating layer, while the tungsten element can stabilize the crystal lattice on the surface of the coated substrate, making the crystal lattice more stable during cycling, thereby improving the electrochemical performance of the coated modified cathode material.

[0036] This invention employs a liquid-phase method, utilizing a phosphorus-containing precipitant (such as phytic acid) as the phosphorus source in the coating layer. Through coordination precipitation with tungsten ions, the slow precipitation of phosphorus and tungsten ions is achieved, resulting in a uniform, continuous, complete, and controllable coating effect. Simultaneously, no other elements are introduced during the precipitation process, thereby reducing the alkalinity of the coated modified cathode material. The preparation method provided by this invention is simple, with mild reaction conditions. The coated modified cathode material prepared by this method exhibits excellent electrochemical performance and has high practicality and application prospects in the field of lithium-ion batteries. Attached Figure Description

[0037] Figure 1 This is a transmission electron microscope image of the coated modified cathode material of Example 1.

[0038] Figure 2 This is a transmission electron microscope image of the coated modified cathode material of Example 2.

[0039] Figure 3 This is a transmission electron microscope image of the coated modified cathode material of Example 3.

[0040] Figure 4 This is a transmission electron microscope image of the coated modified cathode material of Example 4.

[0041] Figure 5 A comparison chart of the cycle performance of batteries at a charge / discharge current of 20 mA / g.

[0042] Figure 6 The pH value is the pH value of the coated modified cathode material in Example 4.

[0043] Figure 7After cycling the battery for 150 cycles at a charge / discharge current of 20 mA / g, the surface lattice changes of the cathode material were observed using a transmission electron microscope. Detailed Implementation

[0044] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0045] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0046] The present invention will be further illustrated below using examples of certain types of cathode material particles; the method is similar when other materials are used as coating substrates. Depending on the specific reaction system, the amounts of phytic acid, metal salt, and the aforementioned core-forming particulate material are varied to achieve uniform coating of different thicknesses for different materials. However, the present invention is not limited to the following embodiments. Unless otherwise specified, all methods described are conventional methods. Unless otherwise specified, all raw materials are obtainable from publicly available commercial sources.

[0047] Example 1

[0048] Preparation of LiNi with phosphorus and tungsten-containing composite coating 0.6 Co 0.2 Mn 0.2 O2 particles as a coated modified cathode material

[0049] 1) Using ternary cathode material LiNi 0.6 Co 0.2 Mn 0.2 Solution A is prepared by mixing 0.5g of O2 particles and 0.03g of tungsten chloride in 60ml of ethanol;

[0050] 2) Disperse 0.005 ml of phytic acid in 30 ml of ethanol to prepare solution B;

[0051] 3) Under stirring, solution B was slowly added to solution A at a rate of 1 mL / min using a peristaltic pump. The molar ratio of phytic acid to tungsten ions was 1:2.1. The reaction was continued at room temperature for 5 hours. After centrifugation, washing, and drying, intermediate product particles were obtained.

[0052] 4) The intermediate product particles obtained in step 3) were calcined at 700°C in an oxygen atmosphere for 3 hours to obtain phosphorus- and tungsten-containing composite-coated LiNi. 0.6 Co 0.2 Mn 0.2 O2 particles are denoted as coated modified cathode material 1.

[0053] Figure 1 This is a transmission electron microscope image of the coated modified cathode material 1 in this embodiment. Figure 1 As can be seen from the data, the modified cathode material 1 has a core-shell structure, the thickness of its composite coating layer is 12 nm, and the composite coating layer uniformly covers the ternary cathode material LiNi. 0.6 Co 0.2 Mn 0.2 The surface of the O2 particles. X-ray photoelectron spectroscopy analysis of the surface content showed that the composite coating layer on the surface contained 8.91 wt% phosphorus and 52.8 wt% tungsten.

[0054] Example 2

[0055] Preparation of LiNi with phosphorus and tungsten-containing composite coating 0.7 Co 0.15 Mn 0.15 O2 particles as a coated modified cathode material

[0056] 1) Using ternary cathode material LiNi 0.7 Co 0.15 Mn 0.15 Solution A is prepared by mixing 0.5g of O2 particles and 0.06ml of tungsten isopropoxide in 60ml of ethanol;

[0057] 2) Disperse 0.005 ml of phytic acid in 30 ml of ethanol to prepare solution B;

[0058] 3) Under stirring, solution B was slowly added to solution A at a rate of 1 mL / min using a peristaltic pump. The molar ratio of phytic acid to tungsten ions was 1:3.3. The reaction was continued at room temperature for 5 hours. After centrifugation, washing, and drying, intermediate product particles were obtained.

[0059] 4) The intermediate product particles obtained in step 3) were calcined at 700°C in an oxygen atmosphere for 3 hours to obtain phosphorus- and tungsten-containing composite-coated LiNi. 0.7 Co 0.15 Mn 0.15 O2 particles are denoted as coated modified cathode material 2.

[0060] Figure 2 These are transmission electron microscope images of the coated modified cathode material 2 in this embodiment. Figure 2 As can be seen from the data, the modified cathode material 2 has a core-shell structure, and the thickness of its composite coating layer is 9 nm. Furthermore, the composite coating layer uniformly covers the ternary cathode material LiNi. 0.7 Co 0.15 Mn 0.15The surface of the O2 particles. X-ray photoelectron spectroscopy analysis of the surface content showed that the composite coating layer on the surface contained 6.69 wt% phosphorus and 59.2 wt% tungsten.

[0061] Example 3

[0062] Preparation of phosphorus- and tungsten-containing composite-coated LiNi 0.8 Co 0.1 Mn 0.1 O2 particles as a coated modified cathode material

[0063] 1) Using LiNi cathode material 0.8 Co 0.1 Mn 0.1 Solution A is prepared by mixing 1g of O2 particles and 0.03g of tungsten chloride in 60ml of ethanol;

[0064] 2) Disperse 0.005 ml of phytic acid in 30 ml of ethanol to prepare solution B;

[0065] 3) Under stirring, solution B was slowly added to solution A at a rate of 1 mL / min using a peristaltic pump. The molar ratio of phytic acid to tungsten ions was 1:2.1. The reaction was continued at room temperature for 5 hours. After centrifugation, washing, and drying, intermediate product particles were obtained.

[0066] 4) The intermediate product particles obtained in step 3) were calcined at 700°C in an oxygen atmosphere for 3 hours to obtain phosphorus- and tungsten-containing composite-coated LiNi. 0.8 Co 0.1 Mn 0.1 O2 particles are designated as coated modified cathode material 3.

[0067] Figure 3 These are transmission electron microscope images of the coated modified cathode material 3 in this embodiment. Figure 3 As can be seen from the data, the modified cathode material 3 has a core-shell structure, the thickness of its composite coating layer is 8 nm, and the composite coating layer uniformly covers the ternary cathode material LiNi. 0.8 Co 0.1 Mn 0.1 The surface of the O2 particles. X-ray photoelectron spectroscopy analysis of the surface content showed that the composite coating layer on the surface contained 7.57 wt% phosphorus and 50.6 wt% tungsten.

[0068] Example 4

[0069] I. Preparation of Phosphorus- and Tungsten-Containing Composite-Coated LiNi 0.83 Co 0.07 Mn 0.1 O2 particles as a coated modified cathode material

[0070] 1) Using ternary cathode material LiNi 0.83 Co 0.07 Mn 0.1 Solution A is prepared by mixing 0.8g of O2 particles and 0.03g of tungsten chloride in 60ml of ethanol;

[0071] 2) Disperse 0.005 ml of phytic acid in 30 ml of ethanol to prepare solution B;

[0072] 3) Under stirring, solution B was slowly added to solution A at a rate of 1 mL / min using a peristaltic pump. The molar ratio of phytic acid to tungsten ions was 1:2.1. The reaction was continued at room temperature for 5 hours. After centrifugation, washing, and drying, intermediate product particles were obtained.

[0073] 4) The intermediate product particles obtained in step 3) were calcined at 700°C in an oxygen atmosphere for 3 hours to obtain phosphorus- and tungsten-containing composite-coated LiNi. 0.83 Co 0.07 Mn 0.1 O2 particles are designated as coated modified cathode material 4.

[0074] Figure 4 These are transmission electron microscope images of the coated modified cathode material 4 in this embodiment. Figure 4 As can be seen, the coated modified cathode material 4 has a core-shell structure, and its composite coating layer is 10 nm thick. Furthermore, the composite coating layer uniformly covers the ternary cathode material LiNi. 0.83 Co 0.07 Mn 0.1 The surface of the O2 particles. X-ray photoelectron spectroscopy analysis of the surface content showed that the composite coating layer on the surface contained 8.24 wt% phosphorus and 51.3 wt% tungsten.

[0075] Example 5

[0076] 1. Preparation of phosphorus-tungsten composite-coated LiNi 0.83 Co 0.07 Mn 0.1 O2 electrode

[0077] 0.18g of the coated modified cathode material 4 prepared in Example 4 above was mixed with 0.01g of conductive additive acetylene black, 0.2g of binder (PVDF mass concentration 5%) and a small amount of solvent NMP. After slurry preparation, coating (aluminum sheet as current collector), and drying, phosphorus- and tungsten composite coated LiNi was obtained. 0.83 Co 0.07 Mn 0.1 The O2 electrode is designated as electrode 5.

[0078] 2. Assemble the battery

[0079] The above-mentioned electrode 5 is used as the positive electrode and lithium metal is used as the negative electrode to assemble a battery. The electrolyte is selected as a 1M carbonate electrolyte, in which the solvent is DMC:DEC:EC = 1:1:1 (W / W / W) and the solute is LiPF6.

[0080] Example 6

[0081] The coated modified cathode materials were prepared according to Example 4, except that the coating thicknesses were 0.5 nm, 17 nm, 25 nm, and 33 nm, respectively, and were designated as coated modified cathode materials 6-1, 6-2, 6-3, and 6-4.

[0082] Comparative Example 1

[0083] The difference between assembled and comparison battery 1 is that the cathode material is an uncoated ternary cathode material, LiNi. 0.83 Co 0.07 Mn 0.1 O2 particulate material, the rest are as described in Example 5.

[0084] Test Example 1

[0085] Taking ternary cathode material LiNi 0.83 Co 0.07 Mn 0.1 O2, the coated modified cathode materials 4, 6-1, 6-2, 6-3, and 6-4 of Examples 4 and 6 were tested for surface alkalinity using the XX method, such as Figure 6 The figure shows the pH value changes of coated modified cathode materials with composite coatings of different thicknesses. As can be seen from the figure, the surface alkalinity of the material decreases significantly with the increase of the coating thickness.

[0086] Test Example 2

[0087] Battery test

[0088] The batteries were subjected to constant current charge-discharge tests using a charge-discharge apparatus. The charge-discharge current was 20 mA / g, the test voltage range was 3–4.3 V, and the test temperature was 25°C. The battery specific capacity and charge-discharge current were calculated based on the actual mass of the electrode materials.

[0089] (1) Battery 5 and comparison battery 1

[0090] Figure 5 The cycle performance of battery 5 and control battery 1 at a charge / discharge current of 20 mA / g was compared. Figure 5It can be seen that the battery prepared using the coated modified cathode material of the present invention has an initial charge specific capacity of 197 mAh / g and 191 mAh / g, respectively; after 150 cycles, the charge specific capacity is 172 mAh / g, while the uncoated ternary cathode material has a charge specific capacity of 150 mAh / g after cycling. Therefore, the coated modified cathode material of the present invention has higher capacity retention and cycle stability.

[0091] Figure 7 The changes in the surface lattice of the above-mentioned battery were observed using transmission electron microscopy before and after 150 cycles at a charge-discharge current of 20 mA / g. In this diagram, 7a represents the ternary cathode material LiNi before cycling. 0.83 Co 0.07 Mn 0.1 O2, 7b is the pre-cycle coated modified cathode material; 4, 7c is the post-cycle ternary cathode material LiNi. 0.83 Co 0.07 Mn 0.1 O2, 7d is the post-cycle coated modified cathode material 4. From Figure 7 As can be seen, the surface lattices of both the coated and uncoated ternary cathode materials were intact before cycling. However, after cycling, the surface lattice of the uncoated ternary cathode material was broken, while the surface lattice of the coated modified cathode material 4 remained intact. This demonstrates that the coated modified cathode material of the present invention exhibits higher lattice stability.

[0092] The exemplary embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a coated modified cathode material, characterized in that, The preparation method includes: 1) Preparation of solution A: Dissolve the coated substrate and tungsten salt in a solvent to obtain solution A; Preparation of solution B: Dissolve the phosphorus-containing precipitant in a solvent to obtain solution B; The coated substrate is selected from a ternary cathode material with high surface alkalinity, and the chemical formula of the ternary cathode material is as follows: LiNi x Co y Mn z O2, where x+y+z=1, x≥0.6; the tungsten salt is selected from at least one of tungsten chloride, sulfate, nitrate, acetate and alkoxide, and the phosphorus-containing precipitant is selected from phytic acid; 2) Under stirring conditions, solution B is added to solution A, and phosphorus-containing precipitant and tungsten element are co-precipitated through coordination to form an intermediate coating layer in situ on the surface of the substrate particles, thus obtaining an intermediate product with a coated core-shell structure; the reaction temperature is 10~25℃, and the reaction time is 1~48h; the molar ratio of the phosphorus-containing precipitant to the metal element is 1:1~5; 3) The intermediate product obtained in step 2) is calcined to obtain the coated modified cathode material; The coated modified cathode material has a core-shell structure, comprising a coating substrate and a composite coating layer. The composite coating layer contains phosphorus and tungsten elements, with the tungsten content in the composite coating layer being 40-70 wt% and the phosphorus content in the composite coating layer being 1-10 wt%. The thickness of the composite coating layer is 1-200 nm. The composite coating layer is prepared by in-situ coating with controllable thickness on the surface of the coating substrate. The coated modified cathode material exhibits low alkalinity and high lattice stability. The composite coating layer is uniform, continuous, complete, and has controllable thickness. The surface pH value of the coated modified cathode material is less than 11.

2. The preparation method according to claim 1, characterized in that, In solution A, the solvent is selected from at least one of water, methanol, ethanol, ethylene glycol, propanol, isopropanol, propylene glycol, n-butanol, acetonitrile, and acetone; Solution B uses the same or different solvent as solution A.

3. The preparation method according to claim 1, characterized in that, The concentration of the coated substrate was 0.1–150 g / L; In solution A, the concentration of the tungsten salt is 0.001~0.1 mol / L; In solution B, the concentration of the phosphorus-containing precipitant is 0.0005~0.05 mol / L.

4. The preparation method according to claim 1, characterized in that, The concentration of the coated substrate is 1~50 g / L.

5. The preparation method according to claim 1, characterized in that, In step 2), solution B is slowly added to solution A using a peristaltic pump.

6. The preparation method according to claim 1, characterized in that, In step 3), the calcination process is carried out in an oxygen-containing atmosphere; the oxygen-containing atmosphere is selected from at least one of air or oxygen.

7. The preparation method according to claim 1, characterized in that, In step 3), the calcination temperature is 400~900℃ and the calcination time is 1~10 h.

8. The preparation method according to claim 1, characterized in that, The calcination temperature is 600~800 ℃, and the calcination time is 1~5 h.

9. The preparation method according to claim 1, characterized in that, x is greater than or equal to 0.6 and less than or equal to 0.

9.

10. The preparation method according to claim 1, characterized in that, The ternary cathode material is selected from LiNi. 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.7 Co 0.15 Mn 0.15 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2 or LiNi 0.83 Co 0.07 Mn 0.1 O2.

11. The preparation method according to claim 1, characterized in that, The high lattice stability of the coated modified cathode material refers to the fact that its surface lattice remains intact after 150 charge-discharge cycles.

12. The preparation method according to claim 1, characterized in that, The tungsten content in the composite coating is 50-60 wt%; the phosphorus content in the composite coating is 5-10 wt%; and the thickness of the composite coating is 5-50 nm.

13. The application of the coated modified cathode material obtained by the preparation method according to any one of claims 1-12 in high-energy lithium storage devices.

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