Coated modified positive electrode material precursor and preparation method thereof, positive electrode material, and secondary battery

Abstract

The present invention provides a coated modified positive electrode material precursor, comprising a positive electrode material precursor and a coating material coated on at least part of the surface of the positive electrode material precursor, wherein the coating material is tungsten-modified calcium zirconate. Providing tungsten-modified calcium zirconate to coat and modify the positive electrode material precursor can significantly improve the cycle stability of the positive electrode material while reducing the negative impact on the discharge specific capacity, effectively extending the service life of the secondary battery, and improving the safety and reliability of the battery.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium ion battery positive electrode materials, and specifically relates to a coated modified positive electrode material precursor and a preparation method thereof, a positive electrode material, and a secondary battery. Background Art

[0002] Lithium-ion batteries are widely used in portable electronic devices, electric vehicles, and energy storage systems due to their high energy density and good cycle performance. In recent years, the development of high-performance cathode materials has been the key to improving the overall performance of lithium batteries. During the charge and discharge process of the liquid electrolyte system, some gases and inactive materials will be produced due to the instability of the surface of the cathode material, resulting in poor battery capacity and cycle. In response to the above problems, coating and doping are the most common modification methods. By adopting the method of coating the cathode material, the side reactions between the material and the electrolyte can be reduced, and the cycle and safety performance of the cathode material can be improved. Among them, oxide coating is a common coating method. Existing materials such as calcium oxide and zirconium oxide have certain limitations in electrochemical performance, which are mainly manifested in insufficient conductivity and poor cycle stability. Summary of the invention

[0003] In response to the above technical problems, the present application provides a coated modified positive electrode material precursor and a preparation method thereof, a positive electrode material, and a secondary battery.

[0004] To achieve the above objectives, this application proposes the following technical solutions:

[0005] In a first aspect, a coated modified positive electrode material precursor comprises a positive electrode material precursor and a coating material coated on at least a portion of the surface of the positive electrode material precursor, wherein the coating material is tungsten-modified calcium zirconate.

[0006] Furthermore, in the tungsten-modified calcium zirconate, the molar ratio of tungsten to zirconium is 0.1% to 10%, preferably 0.5% to 6%.

[0007] Furthermore, the mass ratio of the coating material to the mass of the positive electrode material precursor is 0.2-5%.

[0008] Furthermore, the positive electrode material precursor is nickel-cobalt-manganese hydroxide; the chemical formula of the nickel-cobalt-manganese hydroxide is Ni x Co y Mn z (OH) 2 , where 0.7≤x<1, 0≤y≤0.2, 0<z≤0.3, x+y+z =1.

[0009] In a second aspect, a method for preparing a coated modified positive electrode material precursor is provided, comprising:

[0010] dissolving a soluble tungsten source in water to obtain a tungsten source solution;

[0011] Mixing the tungsten source solution and the calcium zirconate suspension to obtain a mixed solution;

[0012] The pH value of the mixed solution is adjusted to 9-12, and a hydrothermal reaction is performed to obtain a precipitation slurry; the precipitation slurry is subjected to solid-liquid separation, washing and drying to obtain a tungsten-modified calcium zirconate powder;

[0013] The tungsten-modified calcium zirconate powder is mixed with a positive electrode material precursor, and subjected to heat treatment to obtain a tungsten-modified calcium zirconate coated and modified positive electrode material precursor.

[0014] In a third aspect, a positive electrode material is provided, comprising a positive electrode material substrate and a coating layer coated on at least a portion of the surface of the positive electrode material substrate, wherein the coating layer is tungsten-modified calcium zirconate.

[0015] In a fourth aspect, a secondary battery is provided, comprising the aforementioned positive electrode material.

[0016] Compared with the prior art, one or more of the above technical solutions can achieve at least one of the following beneficial effects:

[0017] Providing tungsten-modified calcium zirconate to coat and modify the cathode material precursor can significantly improve the cycle stability of the cathode material while reducing the negative impact on the discharge specific capacity, effectively extending the service life of the secondary battery and improving the safety and reliability of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is the XRD pattern of tungsten-modified calcium zirconate prepared in step S2 of Example 1. DETAILED DESCRIPTION

[0020] The present invention provides a coated modified positive electrode material precursor, comprising a positive electrode material precursor and a coating material coated on at least a part of the surface of the positive electrode material precursor, wherein the coating material is tungsten-modified calcium zirconate.

[0021] By modifying calcium zirconate (CaZrO 3) coated precursors, significantly improving the electrochemical performance of lithium-ion battery cathode materials. The introduction of tungsten can effectively increase the conductivity of calcium zirconate, while improving its structural stability, extending battery life, and improving safety and reliability. Compared with traditional calcium oxide and zirconium oxide, calcium zirconate has better thermal and chemical stability than calcium oxide and zirconium oxide, making it perform better in high temperature and electrolyte environments, avoiding the degradation of calcium oxide and zirconium oxide under these conditions.

[0022] In some preferred embodiments, the molar ratio of tungsten to zirconium in the tungsten-modified calcium zirconate is 0.1% to 10%, preferably 0.5% to 6%, for example 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, etc.

[0023] In some preferred embodiments, the mass of the coating material is 0.2-5% of the mass of the positive electrode material precursor, for example, 0.2%, 0.4%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0024] In some preferred embodiments, the positive electrode material precursor is nickel cobalt manganese hydroxide; the chemical formula of the nickel cobalt manganese hydroxide is Ni x Co y Mn z (OH) 2 , where 0.7≤x<1, 0≤y≤0.2, 0<z≤0.3, x+y+z =1.

[0025] The present invention also provides a method for preparing the aforementioned coated modified positive electrode material precursor, comprising:

[0026] dissolving a soluble tungsten source in water to obtain a tungsten source solution;

[0027] Mixing the tungsten source solution and the calcium zirconate suspension to obtain a mixed solution;

[0028] The pH value of the mixed solution is adjusted to 9-12, and a hydrothermal reaction is performed to obtain a precipitation slurry; the precipitation slurry is subjected to solid-liquid separation, washing, drying and high-temperature sintering to obtain a tungsten-modified calcium zirconate powder;

[0029] The tungsten-modified calcium zirconate powder is mixed with a positive electrode material precursor, and subjected to heat treatment to obtain a tungsten-modified calcium zirconate coated and modified positive electrode material precursor.

[0030] The above method realizes controllable tungsten modification on the surface of calcium zirconate particles, avoiding the disordered distribution of tungsten elements in the entire lattice structure during high-temperature solid-phase reactions. This surface modification is mainly concentrated in the outer layer of calcium zirconate, and has a higher uniformity, better retaining the original lattice structure inside calcium zirconate, avoiding excessive introduction of tungsten elements into the bulk phase of calcium zirconate, thereby reducing lattice stress and structural distortion. In addition, surface tungsten modification can effectively improve the interfacial conductivity of the material and reduce the problem of uneven bulk conductivity that may be caused by solid phase bulk doping. By forming an active layer on the surface of calcium zirconate particles, tungsten can provide additional anchoring points to promote the bonding of the coated material with the calcium zirconate matrix and enhance interface stability. This surface tungsten modification can also form a more active interface during the coating of the precursor, thereby further improving the cycle life and conductivity of the electrode material. In addition, the uniform distribution and precise control of the surface tungsten modification can reduce the interface impedance during the coating process, making the ion and electron conduction paths of the material more continuous and smooth, thereby further improving the electrochemical performance of the electrode.

[0031] In the above preparation method, the positive electrode material precursor can be purchased from the market or prepared by itself. If it is prepared by itself, the conventional co-precipitation method in the art can be used.

[0032] In some preferred embodiments, the soluble tungsten source is at least one of tungsten chloride, ammonium tungstate, sodium tungstate, tungstic acid, and ammonium paratungstate.

[0033] In some preferred embodiments, the temperature of the hydrothermal reaction is 100-180°C, for example, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, etc.; the time of the hydrothermal reaction is 8-16h, for example, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, etc.

[0034] In some preferred embodiments, the high temperature sintering temperature is 800-1200°C, such as 800°C, 850°C, 900°C, 950°C, 1000°C, 1050°C, 1100°C, 1150°C, 1200°C, etc.; the high temperature sintering time is 5-8h, such as 5h, 6h, 7h, 8h, etc.;

[0035] In some preferred embodiments, the heat treatment temperature is 200-400°C, for example, 200°C, 250°C, 300°C, 350°C, 400°C, etc.; the heat treatment time is 2-6h, for example, 2h, 3h, 4h, 5h, 6h, etc.

[0036] The present invention also provides a positive electrode material, comprising a positive electrode material substrate and a coating layer coated on at least a portion of the surface of the positive electrode material substrate, wherein the coating layer is tungsten-modified calcium zirconate.

[0037] In some preferred embodiments, the molar amount of tungsten in the tungsten-doped calcium zirconate is 0.1% to 10% of the molar amount of zirconium, preferably 0.5% to 6%, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, etc.

[0038] In some preferred embodiments, the mass of the tungsten-modified calcium zirconate is 0.2-5% of the mass of the positive electrode material, for example, 0.2%, 0.4%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0039] In some preferred embodiments, the chemical formula of the positive electrode material matrix is ​​LiNi x Co y Mn z O 2 , where 0.7≤x<1, 0≤y≤0.2, 0<z≤0.3, x+y+z =1.

[0040] In some preferred embodiments, the aforementioned coated modified positive electrode material precursor is mixed with a lithium source and then sintered.

[0041] The coated modified positive electrode material precursor and the lithium source can be determined according to the conventional lithium matching ratio, for example, the molar ratio of lithium in the precursor and the lithium source is 1:1~1.1, such as 1:1, 1:1.02, 1:1.05, 1:1.08, 1:1.1, etc.

[0042] The sintering temperature and time may be conventional in the art, for example, sintering at 800-950° C. for 12-24 hours.

[0043] The lithium source may be a conventional lithium source in the art, such as lithium hydroxide or lithium hydroxide hydrate, lithium carbonate, etc.

[0044] The present invention provides a positive electrode, comprising the positive electrode material mentioned above.

[0045] The present invention also provides a secondary battery, comprising the positive electrode.

[0046] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the specification, but the protection scope of the present invention is not limited to the following specific embodiments.

[0047] Example 1

[0048] Step S1, preparation of calcium zirconate: weigh high-purity calcium oxide (CaO) and zirconium oxide (ZrO 2) powder, mixed in a stoichiometric ratio of 1:1 by molar ratio. After uniform grinding in a mortar, the mixture was placed in a high-temperature furnace and calcined at 1300°C for 10 hours to generate calcium zirconate crystals. The calcined product was ground and sieved to 200 mesh to obtain calcium zirconate powder.

[0049] Step S2, preparation of tungsten modified calcium zirconate: calcium zirconate powder and tungsten chloride (WCl 6 ) with a molar ratio of 100:2, dissolve tungsten chloride in deionized water and then add it to the aqueous suspension of calcium zirconate. Adjust the pH to 10, and perform hydrothermal reaction at 120°C for 12 hours to precipitate tungsten to obtain a precipitated slurry. The precipitated slurry is filtered, washed, dried, and then calcined at 1000°C for 6 hours to obtain tungsten-modified calcium zirconate powder, the XRD pattern of which is shown in the figure. Figure 1 shown.

[0050] Step S3, preparation of ternary precursor: prepare nickel, cobalt, and manganese sulfates, mix them in a molar ratio of 90:5:5, dissolve them in water, prepare a mixed metal sulfate solution, use NaOH as a precipitant, and perform a coprecipitation reaction at a reaction temperature of 60°C and a reaction time of 20 hours. During the reaction process, the pH of the reaction system is adjusted to 10±0.1. After precipitation, wash with deionized water three times and dry at 120°C for 12 hours to obtain a ternary precursor powder.

[0051] Step S4, preparation of coated modified ternary positive electrode precursor: tungsten modified calcium zirconate powder and ternary precursor are mixed at a mass ratio of 0.008:1, and pretreated at 250°C for 4 hours to promote the combination of tungsten modified calcium zirconate powder and precursor. After sintering, cool to room temperature to obtain a precursor coated with tungsten modified calcium zirconate powder.

[0052] Step S5: Preparation of positive electrode material

[0053] The coated modified nickel-cobalt-manganese ternary precursor (NCM) and LiOH were mixed at a molar ratio of 1:1.05 and uniformly mixed using a ball mill. The mixture was placed in a high-temperature furnace and sintered at 850°C in an air atmosphere for 22 hours to obtain a coated modified nickel-cobalt-manganese ternary positive electrode material.

[0054] Comparative Example 1

[0055] Step S1, preparation of calcium zirconate: weigh high-purity calcium oxide (CaO) and zirconium oxide (ZrO 2 ) powders were mixed in a stoichiometric ratio of 1:1. After being uniformly ground in a mortar, the mixture was placed in a high-temperature furnace and calcined at 1300°C for 10 hours to generate calcium zirconate crystals. The calcined product was ground and sieved to 200 mesh to obtain calcium zirconate powder.

[0056] Step S2, preparation of ternary precursor: prepare nickel, cobalt, and manganese sulfates, mix them in a molar ratio of Ni:Co:Mn of 90:5:5, dissolve them in water, prepare a mixed metal sulfate solution, use NaOH as a precipitant, and perform a coprecipitation reaction at a reaction temperature of 60°C and a reaction time of 20 hours. During the reaction, the pH of the reaction system is adjusted to 10±0.1. After precipitation, wash with deionized water three times and dry at 120°C for 12 hours to obtain a ternary precursor powder.

[0057] Step S3, preparation of calcium zirconate coated ternary precursor: calcium zirconate and ternary precursor are mixed at a mass ratio of 0.008:1, and pretreated at 250°C for 4 hours to promote the combination of calcium zirconate and precursor. After sintering, the mixture is cooled to room temperature to obtain a calcium zirconate coated precursor.

[0058] Step S4: Preparation of positive electrode materials

[0059] The calcium zirconate-coated ternary precursor and LiOH were mixed at a molar ratio of 1:1.05. A ball mill was used to mix the mixture evenly. The mixture was placed in a high-temperature furnace and sintered at 850°C in an air atmosphere for 22 hours to obtain a nickel-cobalt-manganese ternary positive electrode material coated with calcium zirconate.

[0060] Comparative Example 2

[0061] Step S1, preparation of ternary precursor: prepare nickel, cobalt, and manganese sulfates, mix them in a molar ratio of Ni:Co:Mn of 90:5:5, dissolve them in water, prepare a mixed metal sulfate solution, use NaOH as a precipitant, and perform precipitation reaction at a reaction temperature of 60°C and a reaction time of 20 hours. During the reaction process, the pH of the reaction system is controlled to be 10±0.1. After precipitation, wash with deionized water three times and dry at 120°C for 12 hours to obtain a ternary precursor powder.

[0062] Step S2: Preparation of positive electrode materials

[0063] The nickel-cobalt-manganese ternary precursor (NCM) and lithium hydroxide were mixed at a molar ratio of 1:1.05. A ball mill was used to mix the mixture evenly. The mixture was placed in a high-temperature furnace and sintered at 850°C in an air atmosphere for 22 hours to obtain a nickel-cobalt-manganese ternary positive electrode material.

[0064] Example 2

[0065] Step S1, preparation of calcium zirconate: weigh high-purity calcium oxide (CaO) and zirconium oxide (ZrO 2) powder, mixed in a stoichiometric ratio of 1:1 by molar ratio. After uniform grinding in a mortar, the mixture was placed in a high-temperature furnace and calcined at 1300°C for 10 hours to generate calcium zirconate crystals. The calcined product was ground and sieved to 200 mesh to obtain calcium zirconate powder.

[0066] Step S2, preparation of tungsten modified calcium zirconate: calcium zirconate powder and tungsten chloride (WCl 6 ) with a molar ratio of 100:1, dissolve tungsten chloride in deionized water and add it to the aqueous suspension of calcium zirconate. Adjust the pH to 10, and perform hydrothermal reaction at 120°C for 12 hours to precipitate tungsten to obtain a precipitated slurry. The precipitated slurry is filtered, washed, dried, and then calcined at 950°C for 8 hours to obtain tungsten-modified calcium zirconate powder.

[0067] Step S3, preparation of ternary precursor: prepare nickel, cobalt, and manganese sulfates, mix them in a molar ratio of 90:5:5, dissolve them in water, prepare a mixed metal sulfate solution, use NaOH as a precipitant, and perform a coprecipitation reaction at a reaction temperature of 60°C and a reaction time of 20 hours. During the reaction process, the pH of the reaction system is adjusted to 10±0.1. After precipitation, wash with deionized water three times and dry at 120°C for 12 hours to obtain a ternary precursor powder.

[0068] Step S4, preparation of coated modified ternary positive electrode precursor: tungsten modified calcium zirconate powder and ternary precursor are mixed at a mass ratio of 0.004:1, and pretreated at 300°C for 4 hours to promote the combination of tungsten modified calcium zirconate powder and precursor. After sintering, cool to room temperature to obtain a precursor coated with tungsten modified calcium zirconate powder.

[0069] Step S5: Preparation of positive electrode materials

[0070] The coated modified nickel-cobalt-manganese ternary precursor (NCM) and LiOH were mixed at a molar ratio of 1:1.05 and uniformly mixed using a ball mill. The mixture was placed in a high-temperature furnace and sintered at 850°C in an air atmosphere for 22 hours to obtain a coated modified nickel-cobalt-manganese ternary positive electrode material.

[0071] Example 3

[0072] Step S1, preparation of calcium zirconate: weigh high-purity calcium oxide (CaO) and zirconium oxide (ZrO 2 ) powder, mixed in a stoichiometric ratio of 1:1 by molar ratio. After uniform grinding in a mortar, the mixture was placed in a high-temperature furnace and calcined at 1300°C for 10 hours to generate calcium zirconate crystals. The calcined product was ground and sieved to 200 mesh to obtain calcium zirconate powder.

[0073] Step S2, preparation of tungsten modified calcium zirconate: calcium zirconate powder and tungsten chloride (WCl 6 ) with a molar ratio of 100:4, dissolve tungsten chloride in deionized water and then add it to the aqueous suspension of calcium zirconate. Adjust the pH to 10, and perform hydrothermal reaction at 120°C for 12 hours to precipitate tungsten to obtain a precipitated slurry. The precipitated slurry is filtered, washed, dried, and then calcined at 1100°C for 5 hours to obtain tungsten-modified calcium zirconate powder.

[0074] Step S3, preparation of ternary precursor: prepare nickel, cobalt, and manganese sulfates, mix them in a molar ratio of 90:5:5, dissolve them in water, prepare a mixed metal sulfate solution, use NaOH as a precipitant, and perform a coprecipitation reaction at a reaction temperature of 60°C and a reaction time of 20 hours. During the reaction process, the pH of the reaction system is adjusted to 10±0.1. After precipitation, wash with deionized water three times and dry at 120°C for 12 hours to obtain a ternary precursor powder.

[0075] Step S4, preparation of coated modified ternary positive electrode precursor: tungsten modified calcium zirconate powder and ternary precursor are mixed at a mass ratio of 0.012:1, and pretreated at 350°C for 3 hours to promote the combination of tungsten modified calcium zirconate powder and precursor. After sintering, cool to room temperature to obtain a precursor coated with tungsten modified calcium zirconate powder.

[0076] Step S5: Preparation of positive electrode materials

[0077] The coated modified nickel-cobalt-manganese ternary precursor (NCM) and LiOH were mixed at a molar ratio of 1:1.05 and uniformly mixed using a ball mill. The mixture was placed in a high-temperature furnace and sintered at 850°C in an air atmosphere for 22 hours to obtain a coated modified nickel-cobalt-manganese ternary positive electrode material.

[0078] The positive electrode materials of Examples 1 to 3 and Comparative Examples 1 to 2 were respectively assembled into batteries in the following manner: the positive electrode material, the binder PVDF, and the conductive agent were mixed in a mass ratio of 8:1:1, and after dry grinding for 10 minutes, an appropriate amount of solvent NMP was added, and the positive electrode slurry was obtained after being stirred evenly using a homogenizer. The positive electrode slurry was evenly coated on an aluminum foil, and dried overnight in an oven at 100° C. to ensure that the coating was dry, and then the positive electrode sheet was cut into a button battery disc (12 mm in diameter) of a suitable size; a metal lithium sheet was used as a negative electrode; LB-037 (1M LiPF 6 in DEC:EC:EMC=1:1:1 Vol%) as the electrolyte, add 70μL, Celgard2325 as the separator, and assemble into a button cell.

[0079] The electrical properties of the assembled batteries were tested in the following manner: the test temperature was 25°C, the operating voltage range was 3.0~4.3 V, and they were cycled for 2 cycles at 0.1C, and then cycled for 100 cycles at 0.5C, 1C, and 2C respectively.

[0080] The electrical properties of the battery are shown in Table 1. It can be seen from Table 1 that compared with the battery assembled with the positive electrode material prepared by the uncoated modified precursor in Comparative Example 2, the cycle performance of the battery assembled with the positive electrode material prepared by the coated modified precursor in Example 1 and Comparative Example 1 is significantly improved, and compared with the battery assembled with the positive electrode material prepared by the coated modified precursor in Comparative Example 1, the discharge specific capacity and cycle performance of the battery assembled with the positive electrode material prepared by the coated modified precursor in Example 1 are further improved, which shows that W-doped calcium zirconate has a positive effect on improving the electrical performance.

[0081] Table 1

[0082]

[0083] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a coated modified positive electrode material precursor, characterized in that: The coated modified positive electrode material precursor comprises a positive electrode material precursor and a coating material coated on at least a portion of the surface of the positive electrode material precursor, wherein the coating material is tungsten-modified calcium zirconate; The preparation method comprises: dissolving a soluble tungsten source in water to obtain a tungsten source solution; Mixing the tungsten source solution and the calcium zirconate suspension to obtain a mixed solution; The pH value of the mixed solution is adjusted to 9-12, and a hydrothermal reaction is performed to obtain a precipitation slurry; the precipitation slurry is subjected to solid-liquid separation, washing, drying and high-temperature sintering to obtain a tungsten-modified calcium zirconate powder; Tungsten-modified calcium zirconate powder and a cathode material precursor are mixed and subjected to heat treatment to obtain a tungsten-modified calcium zirconate coated and modified cathode material precursor; in the tungsten-modified calcium zirconate, the molar ratio of tungsten to zirconium is 0.1% to 10%; and the mass of the coating material is 0.2% to 5% of the mass of the cathode material precursor.

2. The method for preparing a coated modified positive electrode material precursor according to claim 1, characterized in that: In the tungsten-modified calcium zirconate, the molar ratio of tungsten to zirconium is 0.5% to 6%.

3. The method for preparing a coated modified positive electrode material precursor according to claim 1, characterized in that: The positive electrode material precursor is nickel cobalt manganese hydroxide; the chemical formula of the nickel cobalt manganese hydroxide is Ni x Co y Mn z (OH)2, where 0.7≤x<1, 0≤y≤0.2, 0<z≤0.3, x+y+z=1.

4. The method for preparing a coated modified positive electrode material precursor according to claim 1, characterized in that: The soluble tungsten source is at least one of tungsten chloride, ammonium tungstate, sodium tungstate, tungstic acid, and ammonium paratungstate.

5. The method for preparing a coated modified positive electrode material precursor according to claim 1, characterized in that: The temperature of the hydrothermal reaction is 100-180°C; the time of the hydrothermal reaction is 8-16h; The high temperature sintering temperature is 800-1200°C; the high temperature sintering time is 5-8h; The temperature of the heat treatment is 200-400° C.; the time of the heat treatment is 2-6 hours.

6. A coated modified cathode material precursor, characterized in that: The method is prepared by any one of claims 1 to 5.

7. A positive electrode material, characterized in that It comprises a positive electrode material substrate and a coating layer coated on at least part of the surface of the positive electrode material substrate, wherein the coating layer is tungsten-modified calcium zirconate; the positive electrode material is obtained by mixing the coated modified positive electrode material precursor according to claim 6 with a lithium source and then sintering.

8. The positive electrode material according to claim 7, characterized in that The chemical formula of the positive electrode material matrix is ​​LiNi x Co y Mn z O2, where 0.7≤x<1, 0≤y≤0.2, 0<z≤0.3, x+y+z=1.

9. A secondary battery, characterized in that: Comprising the positive electrode material as described in claim 7 or 8.

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