Tungsten-doped ternary nickel-containing positive electrode material, preparation method thereof and lithium ion secondary battery

Abstract

The application provides a tungsten-doped nickel-containing ternary positive electrode material, a preparation method thereof, and a lithium ion secondary battery. The tungsten-doped nickel-containing ternary positive electrode material comprises a compound with a general chemical formula of LiNi 1‑x‑y‑ z Co x Mn y W z O2, wherein x>0, y>0, z>0, x+y+z≤0.1, and the distance between oxygen ions and the center of nickel ions in the tungsten-doped nickel-containing ternary positive electrode material is in the range of 1.8-2.2 angstroms. In the tungsten-doped nickel-containing ternary positive electrode material, the amount of amorphous lattice site oxygen ions in the positive electrode material is reduced by contacting the tungsten-doped nickel-containing ternary positive electrode material matrix with a metal in an inert atmosphere, thereby reducing or eliminating the activation of the positive electrode material and improving the first charge-discharge coulombic efficiency.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery electrode materials, and more specifically, to tungsten-doped nickel-containing ternary cathode materials, their preparation methods, and lithium-ion secondary batteries. Background Technology

[0002] Lithium-ion batteries possess advantages such as high operating voltage, high specific energy, long cycle life, light weight, low white discharge, no memory effect, and high performance-price ratio, making them the primary choice for rechargeable power sources in high-power electric vehicles, satellites, aerospace, and other fields. Therefore, lithium-ion batteries and related materials have become a research hotspot for scientists. The cathode material is one of the key materials in lithium-ion batteries, determining their performance. Tungsten-doped high-nickel ternary cathode materials are favored due to their high specific capacity and energy density. However, while tungsten doping technology improves the performance of cathode materials, it also leads to changes in the microstructure of the cathode material, resulting in alterations in its electrochemical performance, such as reduced initial charge-discharge efficiency and significant activation phenomena in the early stages of cycling.

[0003] While existing technologies attempt to optimize the performance of tungsten-doped cathode materials through doping and coating techniques, they have not solved the aforementioned problems caused by tungsten doping. Summary of the Invention

[0004] The main objective of this invention is to provide a tungsten-doped nickel-containing ternary cathode material, its preparation method, and a lithium-ion secondary battery, so as to solve the problems of low initial charge-discharge coulombic efficiency and cathode material activation during cycling caused by tungsten doping in the prior art.

[0005] To achieve the above objectives, according to one aspect of the present invention, a tungsten-doped nickel-containing ternary cathode material is provided, wherein the tungsten-doped nickel-containing ternary cathode material comprises the chemical formula LiNi 1-x-y-z Co x Mn y W z In O2 compounds, where x>0, y>0, z>0, and x+y+z≤0.1, in tungsten-doped nickel-containing ternary cathode materials, the distance of oxygen ions from the center of nickel ions is within... to Within the range.

[0006] Furthermore, in the general chemical formula LiNi 1-x-y-z Co x Mn y W z In compounds containing O2, 0 < z ≤ 0.02.

[0007] According to another aspect of the present invention, a method for preparing the tungsten-doped nickel-containing ternary cathode material described above is provided, the method comprising: - step S1: mixing the tungsten-doped nickel-containing ternary cathode material precursor with a lithium source and calcining it under an oxygen atmosphere to obtain a tungsten-doped nickel-containing ternary cathode material matrix; - step S2: contacting the tungsten-doped nickel-containing ternary cathode material matrix with a metal and heating it under an inert atmosphere to obtain the tungsten-doped nickel-containing ternary cathode material.

[0008] Furthermore, in the above method, the tungsten-doped nickel-containing ternary cathode material precursor has the general chemical formula Ni 1-x-y-z Co x Mn y W z (OH)2, where x>0, y>0, z>0, x+y+z≤0.1.

[0009] Furthermore, in the above method, in step S1, the firing temperature is 750°C to 770°C, and the firing time is 10 hours to 30 hours.

[0010] Furthermore, in the above method, in step S2, the heat treatment temperature is 460°C to 500°C, and the heat treatment time is 5 hours to 10 hours.

[0011] Furthermore, the above method also includes cooling the tungsten-doped nickel-containing ternary cathode material obtained in step S2.

[0012] Furthermore, in the above method, the tungsten-doped nickel-containing ternary cathode material precursor is prepared by a co-precipitation method.

[0013] Furthermore, in the above method, the metal is in the form of a metal sheet.

[0014] Furthermore, in the above method, in step S2, the metal is selected from copper, nickel, tin, or lead.

[0015] According to another aspect of the present invention, a lithium-ion secondary battery is provided, the lithium-ion secondary battery comprising: a positive electrode, a negative electrode, and a separator, wherein the positive electrode comprises a tungsten-doped nickel-containing ternary positive electrode material prepared by the method described above or by the method described above.

[0016] In the tungsten-doped nickel-containing ternary cathode material, its preparation method, and lithium-ion secondary battery of the present invention, by contacting the tungsten-doped nickel-containing ternary cathode material matrix with the metal under an inert atmosphere, the amount of oxygen ions at non-lattice sites in the cathode material is reduced, thereby reducing or eliminating the activation of the cathode material and improving the first charge-discharge coulombic efficiency. Attached Figure Description

[0017] Figure 1The cycle performance test results of a coin cell containing the cathode material prepared in Comparative Example 1 are shown.

[0018] Figure 2 The cycle performance test results of coin cells containing cathode materials prepared in Comparative Example 1 and Example 1 are shown.

[0019] Figure 3 The results of the first charge-discharge test of coin cells containing the cathode materials prepared in Comparative Example 1 and Example 1 are shown.

[0020] Figure 4 The oxygen ion distribution test results of the cathode materials prepared in Comparative Example 1 and Example 1 are shown.

[0021] Figure 5 The cycle performance test results of coin cells containing the cathode materials prepared in Comparative Example 2 and Example 2 are shown.

[0022] Figure 6 The cycle performance test results of coin cells containing the cathode materials prepared in Comparative Example 3 and Example 3 are shown.

[0023] Figure 7 The cycle performance test results of coin cells containing the cathode materials prepared in Comparative Example 4 and Example 4 are shown. Detailed Implementation

[0024] It should be noted that, unless otherwise specified, the various embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments. The following embodiments are merely exemplary and are not intended to limit the scope of protection of the present invention.

[0025] As explained in the background section, when tungsten is introduced during the preparation of the nickel-doped ternary cathode material precursor and a tungsten-doped nickel-doped cathode material matrix is ​​prepared by high-temperature sintering, the valence state balance of the lattice ions changes due to the introduction of high-valence tungsten ions. Unlike traditional layered cathode materials, this material generates some non-lattice oxygen ions (hereinafter referred to as interstitial oxygen), and the matrix exhibits obvious activation phenomena during charge-discharge cycles. Although existing technologies attempt to optimize material performance through doping and coating techniques, they have not solved the problems caused by tungsten doping. Therefore, further improvements to existing cathode materials are still needed. To address the problems in the prior art, according to a typical embodiment of the present invention, a tungsten-doped nickel-doped cathode material is provided, wherein the tungsten-doped nickel-doped cathode material contains the chemical formula LiNi. 1-x-y-z Co x Mn y W zIn O2 compounds, where x>0, y>0, z>0, and x+y+z≤0.1, in tungsten-doped nickel-containing ternary cathode materials, the distance of oxygen ions from the center of nickel ions is within... to Within the range.

[0026] The presence of interstitial oxygen due to the introduction of high-valence tungsten ions broadens the oxygen ion distribution in the material; for example, the distance between the oxygen ion and the nickel ion center is... to Within the range. In contrast, this invention eliminates this crystal defect introduced by tungsten doping, and eliminates interstitial oxygen (interstitial oxygen at a distance from the nickel ion center within...). to less than Within the range and in greater than and less than or equal to Within the range), thus in the tungsten-doped nickel-containing ternary cathode material of the present invention, the distance between the oxygen ion and the nickel ion center is within to Within a certain range. In the technical solution of the present invention, this narrower oxygen ion distribution range reduces or eliminates the activation of the positive electrode material and improves the initial charge-discharge coulombic efficiency.

[0027] Preferably, in the tungsten-doped nickel-containing ternary cathode material, the distance between the oxygen ion and the nickel ion center can be... to Within a certain range, for example, it can be... or

[0028] In one instance, in the general chemical formula LiNi 1-x-y-z Co x Mn y W z In O2, 0 < z ≤ 0.02. Preferably, 0.01 ≤ z ≤ 0.02. When the value of z is within this range, it is possible to further improve the specific capacity and energy density of the material, better reduce or eliminate material activation, and further improve the first charge-discharge coulombic efficiency.

[0029] According to another typical embodiment of the present invention, a method for preparing the tungsten-doped nickel-containing ternary cathode material described above is provided. The method includes: - Step S1: mixing the tungsten-doped nickel-containing ternary cathode material precursor with a lithium source and calcining it under an oxygen atmosphere to obtain a tungsten-doped nickel-containing ternary cathode material matrix; - Step S2: contacting the tungsten-doped nickel-containing ternary cathode material matrix with a metal and heating it under an inert atmosphere to obtain the tungsten-doped nickel-containing ternary cathode material.

[0030] In the technical solution of the present invention, by contacting the tungsten-doped nickel-containing ternary cathode material matrix with the metal under an inert atmosphere, the amount of oxygen ions at non-lattice sites in the cathode material is reduced, thereby reducing or eliminating the activation of the cathode material and improving the first charge-discharge coulombic efficiency.

[0031] This invention does not impose any particular limitation on the lithium source; any lithium source known to those skilled in the art that can be used to prepare nickel-containing ternary cathode materials is acceptable. Preferably, in the above method, the lithium source is preferably one or more of lithium carbonate, lithium hydroxide, lithium nitrate, and lithium acetate; more preferably, it is lithium carbonate, lithium hydroxide, lithium nitrate, or lithium acetate; and most preferably, it is lithium hydroxide monohydrate. The molar ratio of the lithium source to the tungsten-doped nickel-containing ternary cathode material precursor, Li / NCMW, is preferably 1-1.1, more preferably 1.01-1.1, and most preferably 1.01-1.06, wherein the number of moles of the nickel-containing ternary cathode material precursor is the sum of the moles of nickel-cobalt-manganese-tungsten (NCMW) metal, and the number of moles of the lithium source is the moles of lithium metal.

[0032] This invention does not impose any particular limitation on the amount of metal, as long as it can remove interstitial oxygen. Those skilled in the art can select an appropriate amount of metal as needed.

[0033] In one example, the tungsten-doped nickel-containing ternary cathode material precursor has the general chemical formula Ni. 1-x-y-z Co x Mn y W z (OH)₂, where x>0, y>0, z>0, and x+y+z≤0.1. The precursors for tungsten-doped nickel-containing ternary cathode materials are not limited to this; those skilled in the art can select suitable precursors as needed.

[0034] The present invention does not impose any particular limitation on the firing conditions in step S1. Preferably, in step S1, the firing temperature can be from 750°C to 770°C, and the firing time can be from 10 hours to 30 hours. More preferably, the firing temperature can be from 750°C to 765°C, and the firing time can be from 10 hours to 20 hours. For example, the firing temperature can be 750°C, 751°C, 752°C, 753°C, 754°C, 755°C, 756°C, 757°C, 758°C, 759°C, 760°C, 761°C, 762°C, 763°C, 764°C, 765°C, 766°C, 767°C, 768°C, 769°C, or 770°C. The firing time can be 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, 25 hours, 26 hours, 27 hours, 28 hours, 29 hours or 30 hours.

[0035] In one example, in step S2, the heat treatment temperature can be from 460°C to 500°C, and the heat treatment time can be from 5 hours to 10 hours. When the heat treatment temperature and time are within this range, the amount of oxygen ions at non-lattice sites in the material can be reduced in a shorter time and with less energy consumption, thereby reducing or eliminating the activation of the material and improving the first charge-discharge coulombic efficiency.

[0036] Preferably, in step S2, the heat treatment temperature can be between 460°C and 480°C, and the heat treatment time can be between 5 hours and 7 hours. For example, in step S2, the heat treatment temperature can be 460°C, 461°C, 462°C, 463°C, 464°C, 465°C, 466°C, 467°C, 468°C, 469°C, 470°C, 471°C, 472°C, 473°C, 474°C, 475°C, 476°C, 477°C, 478°C, 479°C, or 480°C. The heat treatment time can be 5 hours, 6 hours, or 7 hours.

[0037] In one example, the method may optionally include cooling the tungsten-doped nickel-containing ternary cathode material obtained in step S2. There are no restrictions on the cooling step, as long as the cooling effect is achieved.

[0038] In one example, the tungsten-doped nickel-containing ternary cathode material precursor was prepared by co-precipitation. However, the tungsten-doped nickel-containing ternary cathode material precursor is not limited to this; tungsten-doped nickel-containing ternary cathode material precursors prepared by other methods can be used.

[0039] In one example, the metal is in the form of a metal sheet. When the metal is in the form of a metal sheet, the tungsten-doped nickel-containing ternary cathode material substrate can be placed on the metal sheet, which is more convenient for heat treatment.

[0040] In one example, in step S2, the metal is selected from copper, nickel, tin, or lead. When the metal is selected from copper, nickel, tin, or lead, the amount of oxygen ions at non-lattice sites in the cathode material can be reduced more effectively, thereby better reducing or eliminating the activation of the cathode material and further improving the initial charge-discharge coulombic efficiency.

[0041] According to another typical embodiment of the present invention, a lithium-ion secondary battery is provided, comprising: a positive electrode, a negative electrode, and a separator, wherein the positive electrode comprises a tungsten-doped nickel-containing ternary positive electrode material prepared by the method described above or by the method described above.

[0042] In the lithium-ion secondary battery of the present invention, by contacting the tungsten-doped nickel-containing ternary cathode material matrix with the metal under an inert atmosphere, the amount of oxygen ions at non-lattice sites in the cathode material is reduced, thereby reducing or eliminating the activation of the cathode material and improving the first charge-discharge coulombic efficiency.

[0043] Example

[0044] Preparation of cathode materials

[0045] Example 1

[0046] 9.2 grams of Ni 0.97 Co 0.01 Mn 0.01 W 0.01 The (OH)₂ precursor was mixed uniformly with 4.33 g of lithium hydroxide monohydrate (Li / NCMW = 1.03) and calcined at 765 °C in an oxygen atmosphere for 10 h to obtain a tungsten-doped nickel-containing ternary cathode material matrix. The tungsten-doped nickel-containing ternary cathode material matrix was placed on a 100 μm thick copper sheet and heated at 480 °C in an argon atmosphere for 5 h. After cooling, the tungsten-doped nickel-containing ternary cathode material was obtained.

[0047] Example 2

[0048] 9.2 grams of Ni 0.97 Co 0.01 Mn 0.01 W 0.01 The (OH)₂ precursor was mixed uniformly with 4.33 g of lithium hydroxide monohydrate (Li / NCMW = 1.03) and calcined at 750 °C in an oxygen atmosphere for 15 h to obtain a tungsten-doped nickel-containing ternary cathode material matrix. The tungsten-doped nickel-containing ternary cathode material matrix was placed on a 1 mm thick lead sheet and heated at 480 °C in an argon atmosphere for 5 h. After cooling, the tungsten-doped nickel-containing ternary cathode material was obtained.

[0049] Example 3

[0050] 4.6 grams of Ni 0.97 Co 0.01 Mn 0.01 W 0.01 The (OH)₂ precursor was mixed uniformly with 2.17 g of lithium hydroxide monohydrate (Li / NCMW = 1.03) and calcined at 760 °C in an oxygen atmosphere for 10 h to obtain a tungsten-doped nickel-containing ternary cathode material matrix. The tungsten-doped nickel-containing ternary cathode material matrix was placed on a 100 μm thick nickel sheet and heated at 480 °C in an argon atmosphere for 5 h. After cooling, the tungsten-doped nickel-containing ternary cathode material was obtained.

[0051] Example 4

[0052] 9.2 grams of Ni 0.97 Co0.01 Mn 0.01 W 0.01 The (OH)₂ precursor was mixed uniformly with 4.33 g of lithium hydroxide monohydrate (Li / NCMW = 1.03) and calcined at 750 °C in an oxygen atmosphere for 20 h to obtain a tungsten-doped nickel-containing ternary cathode material matrix. The tungsten-doped nickel-containing ternary cathode material matrix was placed on a 1 mm thick tin sheet and heated at 480 °C in an argon atmosphere for 5 h. After cooling, the tungsten-doped nickel-containing ternary cathode material was obtained.

[0053] Comparative Example 1

[0054] 9.2 grams of Ni 0.97 Co 0.01 Mn 0.01 W 0.01 The (OH)2 precursor was mixed with 4.33 g of lithium hydroxide monohydrate (Li / NCMW = 1.03) and calcined at 765 °C in an oxygen atmosphere for 10 h to obtain a tungsten-doped nickel-containing ternary cathode material.

[0055] Comparative Example 2

[0056] 9.2 grams of Ni 0.97 Co 0.01 Mn 0.01 W 0.01 The (OH)2 precursor was mixed with 4.33 g of lithium hydroxide monohydrate (Li / NCMW = 1.03) and calcined at 750 °C in an oxygen atmosphere for 15 h to obtain a tungsten-doped nickel-containing ternary cathode material.

[0057] Comparative Example 3

[0058] 4.6 grams of Ni 0.97 Co 0.01 Mn 0.01 W 0.01 The (OH)2 precursor was mixed with 2.17 g of lithium hydroxide monohydrate (Li / NCMW = 1.03) and calcined at 760 °C in an oxygen atmosphere for 10 h to obtain a tungsten-doped nickel-containing ternary cathode material.

[0059] Comparative Example 4

[0060] 9.2 grams of Ni 0.97 Co 0.01 Mn 0.01 W 0.01 The (OH)2 precursor was mixed with 4.33 g of lithium hydroxide monohydrate (Li / NCMW = 1.03) and calcined at 750 °C in an oxygen atmosphere for 20 h to obtain a tungsten-doped nickel-containing ternary cathode material.

[0061] Preparation of button cells

[0062] Preparation of positive electrode

[0063] 0.425 g of the positive electrode material prepared in the above examples or comparative examples, 0.035 g of acetylene black conductive agent, and 0.040 g of polyvinylidene fluoride were dispersed in 0.6 g of N-methylpyrrolidone and mixed evenly to obtain a positive electrode mixture slurry. Subsequently, the positive electrode mixture slurry was coated onto a pre-weighed aluminum foil, dried, and pressed into a sheet to obtain a positive electrode sheet, which was then weighed for later use.

[0064] Preparation of electrolyte

[0065] An electrolyte was prepared by mixing 15.0 g of ethylene carbonate, 70.0 g of dimethyl carbonate and 15.0 g of lithium hexafluorophosphate.

[0066] Battery assembly

[0067] Assemble CR2025 coin cells inside a glove box. Use the positive electrode sheet prepared in the above steps as the positive electrode and the lithium sheet as the negative electrode. Assemble the positive electrode, negative electrode, separator, and coin cell casing, inject electrolyte, and seal with a mold to obtain the coin cell to be tested.

[0068] First charge / discharge test of battery:

[0069] Charging: Apply 20 mAg to the positive electrode. -1 The current density is constant-current charging to 4.25V, and then charged at a constant voltage of 4.25V until the current density is ≤5mAg. -1 Charging complete; Discharging: The positive electrode is charged with 20 mAg. -1 The current density is constant current discharged to 2.0V;

[0070] Test temperature: 30℃.

[0071] Battery cycle performance testing

[0072] Charging: Apply 200 mAg to the positive electrode. -1 The current density is constant-current charging to 4.25V, and then charged at a constant voltage of 4.25V until the current density is ≤5mAg. -1 Charging complete; Discharging: The positive electrode is charged at 1000 mAg. -1 The current density is constant current discharged to 2.5V; the above is repeated for 100 charge-discharge cycles.

[0073] Test temperature: 60℃.

[0074] Test Results

[0075] 1. Cycle performance test results of coin cells containing the cathode materials prepared in Comparative Example 1 and Example 1, respectively. Figure 1-2As shown in the image. From Figure 1-2 As can be seen, the cathode material prepared in Comparative Example 1 exhibits a significant activation process at the beginning of the cycling stage, while the cathode material prepared in Example 1 does not exhibit a significant activation process at the beginning of the cycling stage.

[0076] 2. The initial charge-discharge test results of coin cells containing the cathode materials prepared in Comparative Example 1 and Example 1, respectively. Figure 3 As shown in the image. From Figure 3 It can be seen that the coin cell containing the cathode material prepared in Example 1 has a higher initial cycle efficiency than the coin cell containing the cathode material prepared in Comparative Example 1.

[0077] 3. The oxygen ion distribution test results of the cathode materials prepared in Comparative Example 1 and Example 1 are as follows: Figure 4 The X-ray absorption spectrum is shown in the figure, where Figure 4 A shows the full absorption spectrum. Since the cathode materials prepared in Comparative Example 1 and Example 1 are structurally very similar, with only minor differences in interstitial oxygen, the spectra are not significantly different. Figure 4 B shows a magnified view of a portion of A;

[0078] Figure 4 C shows the fit Figure 4 The result obtained in A shows that, with nickel atoms at the center, the first layer is oxygen atoms, and the second layer is nickel atoms. From this figure, it can be seen that the oxygen ion distribution of the cathode material prepared in Comparative Example 1 is... The distribution of oxygen ions in the positive electrode material prepared in Example 1 is as follows: (see Figure 4 The circles in C represent the locations of... oxygen ions and located Oxygen ions). Therefore, compared with Comparative Example 1, the present invention eliminates the crystal defects introduced by tungsten doping and eliminates interstitial oxygen (interstitial oxygen is located at a distance of approximately 1000 kJ / kJ from the nickel ion center). to less than Within the range and in greater than and less than or equal to (within the range).

[0079] 4. The cycle performance test results of coin cells containing the cathode materials prepared in Comparative Examples 2-4 and Examples 2-4 are respectively in... Figure 5-7 As shown in the image. From Figure 5-7 It can be seen that the cathode materials prepared in Comparative Examples 2-4 exhibit a significant activation process at the beginning of the cycling stage, while the cathode materials prepared in Examples 2-4 do not exhibit a significant activation process at the beginning of the cycling stage.

[0080] The experimental results above show that the embodiments of the present invention achieve the following technical effects:

[0081] In the tungsten-doped nickel-containing ternary cathode material, its preparation method, and lithium-ion secondary battery of the present invention, by contacting the tungsten-doped nickel-containing ternary cathode material matrix with the metal under an inert atmosphere, the amount of oxygen ions at non-lattice sites in the cathode material is reduced, thereby reducing or eliminating the activation of the cathode material and improving the first charge-discharge coulombic efficiency.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A tungsten-doped nickel-containing ternary cathode material, comprising the chemical formula LiNi 1-x-y-z Co x Mn y W z Compounds of O2, wherein x>0, y>0, z>0, x+y+z≤0.1, are characterized by, In the tungsten-doped nickel-containing ternary cathode material, the distance between the oxygen ion and the center of the nickel ion is... to Within the range.

2. The tungsten-doped nickel-containing ternary cathode material according to claim 1, characterized in that, 0＜z≤0.02。 3. A method for preparing the tungsten-doped nickel-containing ternary cathode material as described in claim 1 or 2, characterized in that, Includes the following steps: - Step S1: Mix the tungsten-doped nickel-containing ternary cathode material precursor with a lithium source and calcine it in an oxygen atmosphere to obtain the tungsten-doped nickel-containing ternary cathode material matrix. - Step S2: The tungsten-doped nickel-containing ternary cathode material matrix is ​​brought into contact with a metal and heated under an inert atmosphere to obtain the tungsten-doped nickel-containing ternary cathode material.

4. The method according to claim 3, characterized in that, The tungsten-doped nickel-containing ternary cathode material precursor has the general chemical formula Ni. 1-x-y-z Co x Mn y W z (OH)2, where x>0, y>0, z>0, x+y+z≤0.

1.

5. The method according to claim 3 or 4, characterized in that, In step S1, the firing temperature is 750°C to 770°C, and the firing time is 10 hours to 30 hours.

6. The method according to claim 3 or 4, characterized in that, In step S2, the heat treatment temperature is 460°C to 500°C, and the heat treatment time is 5 hours to 10 hours.

7. The method according to claim 3 or 4, characterized in that, The method further includes cooling the tungsten-doped nickel-containing ternary cathode material obtained in step S2.

8. The method according to claim 3 or 4, characterized in that, The tungsten-doped nickel-containing ternary cathode material precursor is prepared by co-precipitation.

9. The method according to claim 3 or 4, characterized in that, The metal is in the form of a metal sheet.

10. The method according to claim 3 or 4, characterized in that, In step S2, the metal is selected from copper, nickel, tin or lead.

11. A lithium-ion secondary battery, comprising: Positive electrode plate, Negative electrode, and Diaphragm, The positive electrode is characterized in that the positive electrode comprises a tungsten-doped nickel-containing ternary positive electrode material as described in claim 1 or 2, or prepared by any one of claims 3-10.

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