A doped modified ternary positive electrode material, a preparation method thereof and a battery

Abstract

The application discloses a doped modified ternary positive electrode material, a preparation method thereof and a battery, and belongs to the technical field of batteries and ternary materials. 0.8 Co 0.1 Mn 0.1 (OH)2, lithium hydroxide and a dopant are mixed and ground to form a mixture; the mixture is calcined in sections in an oxygen atmosphere, ground and sieved to obtain the doped modified ternary positive electrode material. In the high-nickel ternary material, the application dopes appropriate amounts of Ti and V, and the two improve the stability of the material structure, reduce the degree of cation mixing, improve the reversible degree of the material and the kinetics of the reaction, and improve the electrochemical performance of the material through synergistic effect.

Description

Technical Field

[0001] This invention belongs to the field of battery and ternary material technology. More specifically, this invention relates to a doped and modified ternary cathode material, its preparation method, and a battery. Background Technology

[0002] Due to the non-renewable nature of fossil fuels and the numerous environmental problems they cause, the combined use of green and renewable energy sources (such as solar, wind, tidal, and nuclear energy) has become an international trend. However, mechanical, chemical, and thermal energy storage, with their low energy conversion efficiency, easily lead to energy waste and are increasingly unable to meet the needs of modern society. Electrochemical energy storage, as an energy storage system with higher energy conversion efficiency, has attracted the attention of many scholars and experts. Electrochemical energy storage technology developed rapidly in the 20th century, and initial battery technology emerged accordingly. However, with social development, it has become increasingly unable to meet demands in terms of energy density, cycle life, price, and environmental friendliness. Lithium-ion batteries have significant comprehensive advantages in energy density, cycle life, price, and environmental friendliness, and have gradually become the mainstream of today's electrochemical energy storage systems.

[0003] High-nickel ternary cathode materials (such as NCM811) used in lithium-ion batteries possess high specific capacity, enabling high energy density and effectively reducing battery costs. However, high-nickel materials also suffer from poor cycle stability and thermal stability. Numerous studies have shown that different synthesis methods can significantly influence the electrochemical performance of NCM811 cathode materials by microscopically controlling its microstructure and interfacial properties. Co-precipitation, which allows for more uniform morphological control, is becoming a growing trend in high-nickel cathode materials. Sol-gel and hydrothermal methods offer greater potential and advantages in cathode material nanostructure design, but cycle stability remains a critical issue. Spray drying offers significant advantages in cathode material processing and synthesis, but structural defects introduced during synthesis limit its widespread application. High-temperature solid-state methods, discovered earlier and with a longer history of application, have mature processes suitable for widespread use and development. All these synthesis methods for NCM811 can effectively improve its electrochemical performance, thereby enhancing its application value.

[0004] While the high-temperature solid-state synthesis of NCM811 offers good cost control and is suitable for industrial production, this process introduces several problems: low tap density, cation mixing, irreversible phase transition, and loss of active lithium due to side reactions, thus affecting its electrochemical performance. Therefore, researching ways to improve the electrochemical performance of high-nickel ternary cathode materials is of great significance. Summary of the Invention

[0005] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0006] To achieve these objectives and other advantages of the present invention, a method for preparing a doped and modified ternary cathode material is provided, characterized by comprising the following steps:

[0007] Step 1: Ni 0.8 Co 0.1 Mn 0.1 (OH)2, lithium hydroxide, and dopants are mixed and ground to form a mixture;

[0008] Step 2: The mixture is calcined in stages in an oxygen atmosphere, ground and sieved to obtain the doped and modified ternary cathode material.

[0009] Preferably, in step one, Ni 0.8 Co 0.1 Mn 0.1 The molar ratio of (OH)2 to lithium hydroxide is 1:1.03~1.07.

[0010] Preferably, in step one, the dopant is one or both of titanium dioxide and vanadium pentoxide; wherein, the titanium dioxide and the Ni 0.8 Co 0.1 Mn 0.1 The molar ratio of (OH)₂ is 0.001~0.005:1; the vanadium pentoxide and the Ni 0.8 Co 0.1 Mn 0.1 The molar ratio of (OH)2 is 0.001~0.005:1.

[0011] Preferably, in step two, the specific steps of segmented calcination are as follows: at a certain heating rate, the temperature is raised to 100~200℃ and held for 0.2~1 h, then raised to 450~550℃ and held for 3~7 h, then raised to 800~900℃ and held for 3~7 h, then lowered to 750~800℃ at a certain cooling rate and held for 8~12 h, and finally lowered to 100~200℃.

[0012] Preferably, the heating rate is 2~4℃ / min and the cooling rate is 1~3℃ / min.

[0013] Preferably, in step two, the material is ground through a 400-600 mesh sieve.

[0014] Preferably, the dopant is titanium dioxide and vanadium pentoxide.

[0015] Preferably, the titanium dioxide and vanadium pentoxide are modified before being added, including the following steps:

[0016] S11. Mix TiO2 and V2O5 in a molar ratio of 1~5:1~5, add to deionized water, stir evenly, then add polyethylene glycol 400, stir evenly to obtain a dispersion.

[0017] S12. Add acrylamide and ammonium persulfate to the dispersion, react at 60~90℃ for 4~8h, filter, wash with anhydrous ethanol, and dry under vacuum to obtain product A;

[0018] S13. Add the silane coupling agent to anhydrous ethanol to prepare a silane coupling agent solution with a concentration of 1~10wt%. Mix product A with the silane coupling agent solution, heat to 60~80℃ and stir for 1~3h. Filter, wash with anhydrous ethanol and deionized water in sequence, and dry under vacuum to obtain modified TiO2 and V2O5.

[0019] Preferably, in S11, the mass ratio of the total mass of TiO2 and V2O5, the mass ratio of deionized water and the mass ratio of polyethylene glycol 400 is 1:10~50:0.1~0.3.

[0020] Preferably, in S12, the total mass ratio of TiO2 and V2O5 to acrylamide is 1:0.1~2; and the mass ratio of acrylamide to ammonium persulfate is 5~20:0.1.

[0021] Preferably, in step S13, the mass ratio of product A to the silane coupling agent solution is 1:3~8.

[0022] A doped and modified ternary cathode material is prepared by the doped and modified ternary cathode material preparation method described above.

[0023] A battery, wherein the positive electrode material of the battery is a doped and modified ternary positive electrode material as described above.

[0024] This invention offers at least the following beneficial effects: By doping high-nickel ternary materials with appropriate amounts of Ti and V, the two work synergistically to improve the stability of the material structure, reduce cation mixing, enhance the reversibility and reaction kinetics of the material, and improve its electrochemical performance. Furthermore, this invention includes modifying TiO2 and V2O5 to give them good dispersibility and stability, allowing Ti and V to be uniformly doped into the NCM lattice, making its structure more stable. Specifically, a dispersion is first prepared by adding polyethylene glycol as a dispersant, and then polyacrylamide is formed on the surface of TiO2 and V2O5 using ammonium persulfate and acrylamide as initiators, improving their dispersibility and interfacial reactivity, which is beneficial for subsequent reactions. Simultaneously, carbon and nitrogen elements are introduced to further improve the conductivity of the material. Finally, a silane coupling agent is added to further improve its dispersibility and stability.

[0025] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0026] Figure 1 The XRD patterns of NCM-0.24, NCM-0.32 and NCM-0.40 prepared in Examples 1-3 of this invention;

[0027] Figure 2 The images show SEM images of NCM-0.32 prepared in Example 1 and NCM-1.05 prepared in Comparative Example 1 at different magnifications (5K, 1W, 2W), where A represents NCM-1.05, B represents NCM-0.32, 1 represents 2W, 2 represents 1W, and 3 represents 5K.

[0028] Figure 3 The first charge-discharge curves at 0.1C are for NCM-0.24, NCM-0.32, and NCM-0.40 prepared in Examples 1-3 of this invention.

[0029] Figure 4 The cycling performance of NCM-0.24, NCM-0.32 and NCM-0.40 prepared in Examples 1-3 of this invention is shown in the graph at 1C.

[0030] Figure 5 Rate performance diagrams of NCM-0.24, NCM-0.32, and NCM-0.40 prepared in Examples 1-3 of this invention;

[0031] Figure 6 Cyclic voltammetry diagrams of NCM-0.24, NCM-0.32, and NCM-0.40 prepared in Examples 1-3 of this invention;

[0032] Figure 7 Impedance maps before cycling of NCM-0.24, NCM-0.32 and NCM-0.40 prepared in Examples 1-3 of this invention;

[0033] Figure 8 The cyclic impedance diagrams of NCM-0.24, NCM-0.32, and NCM-0.40 prepared in Examples 1-3 of this invention;

[0034] Figure 9 The rate performance diagrams are for NCM-0.32 prepared in Example 1 and NCM-1.05 prepared in Comparative Example 1. Detailed Implementation

[0035] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0036] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0037] Example 1

[0038] A method for preparing a doped and modified ternary cathode material includes the following steps:

[0039] Step 1: Weigh out 92.3g of Ni at a molar ratio of 1:1.05:0.004. 0.8 Co 0.1 Mn 0.1 (OH)2, 44.1g LiOH·H2O and 0.32g TiO2 are mixed and ground thoroughly for 2 h to form a mixture;

[0040] Step 2: Place the mixture in a muffle furnace and calcine it in stages in an oxygen atmosphere. The temperature is raised to 150℃ and held for 0.5 h, raised to 500℃ and held for 5 h, raised to 850℃ and held for 5 h, cooled to 780℃ and held for 10 h, and finally cooled to 150℃. After removing the material, grind it and filter it through a 500-mesh sieve to obtain the doped and modified ternary cathode material NCM-0.32. The heating rate is 3℃ / min and the cooling rate is 2℃ / min.

[0041] Example 2

[0042] In this embodiment, the amount of TiO2 used is 0.24g (0.003mol), and the remaining steps are the same as in Example 1, to obtain the doped and modified ternary cathode material NCM-0.24.

[0043] Example 3

[0044] In this embodiment, the amount of TiO2 used is 0.40g (0.005mol), and the remaining steps are the same as in Example 1, to obtain the doped and modified ternary cathode material NCM-0.40.

[0045] Example 4

[0046] In this embodiment, 0.004 mol V2O5 (0.73 g) was used to replace TiO2, and the remaining steps were the same as in Example 1, to obtain the doped and modified ternary cathode material NCM-0.73.

[0047] Example 5

[0048] A method for preparing a doped and modified ternary cathode material includes the following steps:

[0049] Step 1: Weigh out 92.3g of Ni in a molar ratio of 1:1.05:0.004:0.004. 0.8 Co 0.1 Mn 0.1 (OH)2, 44.1g LiOH·H2O, 0.32g TiO2, and 0.73g V2O5 were mixed and ground thoroughly for 2 hours to form a mixture;

[0050] Step 2: Place the mixture in a muffle furnace and calcine it in stages under an oxygen atmosphere. The temperature is raised to 150℃ and held for 0.5 h, then raised to 500℃ and held for 5 h, then raised to 850℃ and held for 5 h, then lowered to 780℃ and held for 10 h, and finally lowered to 150℃. After removing the material, grind it and filter it through a 500-mesh sieve to obtain the doped and modified ternary cathode material NCM-Ti-V. The heating rate is 3℃ / min and the cooling rate is 2℃ / min.

[0051] In this embodiment, TiO2 and V2O5 are doped, and the remaining steps are the same as in Example 1.

[0052] Example 6

[0053] In this embodiment, TiO2 and V2O5 are modified before addition to obtain modified TiO2 and V2O5, i.e., modified TiO2 and V2O5 are used to replace TiO2 and V2O5. The remaining steps are the same as in Example 5 to obtain the doped modified ternary cathode material NCM-1. The specific method for modifying TiO2 and V2O5 includes the following steps:

[0054] S11. Mix TiO2 and V2O5 in a molar ratio of 1:1, add to deionized water, stir until homogeneous, then add polyethylene glycol 400 and stir until homogeneous to obtain a dispersion; the mass ratio of the total mass of TiO2 and V2O5, the mass ratio of deionized water to polyethylene glycol 400 is 1:20:0.2.

[0055] S12. Add acrylamide and ammonium persulfate to the dispersion, react at 80℃ for 6 h, filter, wash 3 times with anhydrous ethanol, and dry under vacuum to obtain product A; wherein, the total mass ratio of TiO2 and V2O5 to acrylamide is 1:0.5; the mass ratio of acrylamide to ammonium persulfate is 10:0.1.

[0056] S13. Add silane coupling agent KH550 to anhydrous ethanol to prepare a silane coupling agent solution with a concentration of 5wt%. Mix product A and the silane coupling agent solution at a mass ratio of 1:5, heat to 70℃ and stir for 2 hours. Filter, wash three times with anhydrous ethanol and deionized water in sequence, and dry under vacuum to obtain modified TiO2 and V2O5.

[0057] Example 7

[0058] In this embodiment, TiO2 and V2O5 are modified before addition to obtain modified TiO2 and V2O5, i.e., modified TiO2 and V2O5 are used to replace TiO2 and V2O5. The remaining steps are the same as in Example 5 to obtain the doped modified ternary cathode material NCM-2. The specific method for modifying TiO2 and V2O5 includes the following steps:

[0059] S11. Mix TiO2 and V2O5 in a molar ratio of 1:1, add to deionized water, stir until homogeneous, then add polyethylene glycol 400, stir until homogeneous, filter, wash three times with anhydrous ethanol, and vacuum dry to obtain product A; the mass ratio of total mass of TiO2 and V2O5, deionized water and polyethylene glycol 400 is 1:20:0.2.

[0060] S12. Add silane coupling agent KH550 to anhydrous ethanol to prepare a silane coupling agent solution with a concentration of 5wt%. Mix product A and the silane coupling agent solution at a mass ratio of 1:5, heat to 70℃ and stir for 2 hours. Filter, wash three times with anhydrous ethanol and deionized water in sequence, and dry under vacuum to obtain modified TiO2 and V2O5.

[0061] Compared to Example 6, this example does not involve polyacrylamide treatment.

[0062] Example 8

[0063] In this embodiment, TiO2 and V2O5 are modified before addition to obtain modified TiO2 and V2O5, i.e., modified TiO2 and V2O5 are used to replace TiO2 and V2O5. The remaining steps are the same as in Example 5 to obtain the doped modified ternary cathode material NCM-3. The specific method for modifying TiO2 and V2O5 includes the following steps:

[0064] S11. Mix TiO2 and V2O5 in a molar ratio of 1:1, add to deionized water, stir until homogeneous, then add polyethylene glycol 400 and stir until homogeneous to obtain a dispersion; the mass ratio of the total mass of TiO2 and V2O5, the mass ratio of deionized water to polyethylene glycol 400 is 1:20:0.2.

[0065] S12. Acrylamide and ammonium persulfate were added to the dispersion and reacted at 80°C for 6 hours. The mixture was then filtered, washed three times with anhydrous ethanol, and dried under vacuum to obtain modified TiO2 and V2O5. The mass ratio of the total mass of TiO2 and V2O5 to that of acrylamide was 1:0.5, and the mass ratio of acrylamide to ammonium persulfate was 10:0.1.

[0066] Compared to Example 6, this example does not involve silane coupling agent treatment.

[0067] Example 9

[0068] In this embodiment, TiO2 and V2O5 are modified before addition to obtain modified TiO2 and V2O5, i.e., modified TiO2 and V2O5 are used to replace TiO2 and V2O5. The remaining steps are the same as in Example 5 to obtain the doped modified ternary cathode material NCM-4. The specific method for modifying TiO2 and V2O5 includes the following steps:

[0069] S11. Mix TiO2 and V2O5 at a molar ratio of 1:1 and add them to deionized water. Stir until homogeneous to obtain a dispersion. The mass ratio of the total mass of TiO2 and V2O5 to the mass of deionized water is 1:20.

[0070] S12. Add acrylamide and ammonium persulfate to the dispersion, react at 80℃ for 6 h, filter, wash 3 times with anhydrous ethanol, and dry under vacuum to obtain product A; wherein, the total mass ratio of TiO2 and V2O5 to acrylamide is 1:0.5; the mass ratio of acrylamide to ammonium persulfate is 10:0.1.

[0071] S13. Add silane coupling agent KH550 to anhydrous ethanol to prepare a silane coupling agent solution with a concentration of 5wt%. Mix product A and the silane coupling agent solution at a mass ratio of 1:5, heat to 70℃ and stir for 2 hours. Filter, wash three times with anhydrous ethanol and deionized water in sequence, and dry under vacuum to obtain modified TiO2 and V2O5.

[0072] Compared to Example 6, this example does not use polyethylene glycol 400.

[0073] Comparative Example 1

[0074] A method for preparing a ternary cathode material includes the following steps:

[0075] Step 1: Weigh out 92.3g of Ni at a molar ratio of 1:1.05. 0.8 Co 0.1 Mn 0.1 (OH)2 and 44.1g LiOH·H2O were mixed and ground thoroughly for 2 hours to form a mixture;

[0076] Step 2: Place the mixture in a muffle furnace and calcine it in stages under an oxygen atmosphere. The temperature is raised to 150℃ and held for 0.5 h, then raised to 500℃ and held for 5 h, then raised to 850℃ and held for 5 h, then lowered to 780℃ and held for 10 h, and finally lowered to 150℃. After removing the material, grind it and filter it through a 500-mesh sieve to obtain the ternary cathode material NCM-1.05. The heating rate is 3℃ / min and the cooling rate is 2℃ / min.

[0077] In this comparative example, titanium dioxide is not doped, and the remaining steps are the same as in Example 1.

[0078] Figure 1 The XRD patterns of NCM-0.24, NCM-0.32, and NCM-0.40 prepared in Examples 1-3 are shown in the figures. It can be seen from the figures that NCM-0.24, NCM-0.32, and NCM-0.40 are largely consistent with the standard card PDF#09-0063. It can be observed that with the increase of Ti... 4+ As the concentration increases, the peak intensity decreases.

[0079] Figure 2 SEM images of NCM-0.32 prepared in Example 1 and NCM-1.05 prepared in Comparative Example 1 at different magnifications (5K, 1W, 2W) are shown. A1-A3 represent NCM-1.05, B1-B3 represent NCM-0.32, A1 and B1 represent 2W magnification, A2 and B2 represent 1W magnification, and A3 and B3 represent 5K magnification. It can be seen that titanium doping results in more uniform particle size, reduced agglomeration, and a smoother surface. This change in material structure indicates that titanium dioxide effectively incorporates into the material and alters its surface state, reducing the tendency for agglomeration and significantly improving the morphology and particle size, while increasing the resistance to ion movement within the material.

[0080] Electrochemical performance testing:

[0081] (1) Cyclic Voltmeter-Vertical Voltage (CV) Test

[0082] Cyclic voltammetry (CV) works by applying a linear scanning voltage from an initial voltage point, changing the voltage direction upon reaching the endpoint, and repeating this process repeatedly. The change in current with electrode potential is recorded to investigate the chemical reactions and reversibility of electrode materials. This experiment used a CHI660D from Shanghai Chenhua Instrument Co., Ltd., with a voltage range of 2.7–4.3 V and a scan rate of 0.2 mV / s.

[0083] (2) Electro-acoustic impedance testing (EIS)

[0084] Electrochemical impedance spectroscopy (EIS) is a testing method that uses a small alternating current to perturb the electrodes to study changes in interfacial resistance. The electrochemical workstation used in this experiment is a CHI660E model, with a test frequency range of 0.01–100 kHz and an amplitude of 5 mV.

[0085] (3) Battery assembly

[0086] First, 0.8 g of positive electrode material, 0.1 g of acetylene black, and 0.1 g of PVDF were placed in a glass bottle. 1000 μL of NMP was added to the glass bottle, and the mixture was stirred for 12 hours to obtain an electrode slurry. The prepared electrode slurry was then evenly coated onto a 12 cm aluminum sheet using a coating machine. The aluminum sheet containing the electrode slurry was placed in a vacuum oven and vacuum dried for 6 hours to obtain the positive electrode sheet. A lithium metal sheet was used as the negative electrode. The separator was an imported polypropylene microporous membrane (Celgard 2400). The electrolyte was a mixture of equal amounts of 1 mol / L LiPF6, ethylene carbonate (EC), and dimethyl carbonate (DMC). The battery, model CR2032, was assembled in an argon glove box.

[0087] Figure 3 The initial charge-discharge curves at 0.1C for NCM-0.24, NCM-0.32, and NCM-0.40 prepared in Examples 1-3 are shown in Table 1. It can be seen that appropriate titanium doping can improve the physical and electrochemical properties of the electrode materials, possibly due to the presence of Ti. 4+ This increases the interlayer spacing of the material, but excessive doping may affect the stability of the material structure, resulting in a decrease in coulombic efficiency and discharge specific capacity.

[0088] Table 1

[0089]

[0090] Figure 4 Table 2 shows the cycling performance of NCM-0.24, NCM-0.32, and NCM-0.40 prepared in Examples 1-3 at 1C. It can be seen that an appropriate amount of Ti...4+ Doping with Ti enhances the MO bonds, improves the stability of the material structure, and thus improves the cycling performance of the material, with NCM-0.32 exhibiting the best cycling performance; Ti 4+ Excessive doping can reduce the stability between materials and decrease their cycling performance.

[0091] Table 2

[0092]

[0093] Figure 5 Table 3 shows the rate performance of NCM-0.24, NCM-0.32, and NCM-0.40 prepared in Examples 1-3. Specifically, the data represents the discharge specific capacity at 0.1C, 0.2C, 0.5C, 1C, 2C, and 5C, and finally back to 0.1C. It can be seen that the discharge specific capacities of these three materials at 5C are 100.61, 152.22, and 132.99 mAh / g, respectively. NCM-0.32 exhibits the best discharge specific capacity. At high rates, the material structure of NCM-0.32 is more stable than that of NCM-0.24 and NCM-0.40, indicating that an appropriate amount of titanium can improve the stability of the material structure.

[0094] Table 3

[0095]

[0096] Figure 6 Cyclic voltammograms of NCM-0.24, NCM-0.32, and NCM-0.40 prepared in Examples 1-3 are shown. The potential difference for NCM-0.24 is 0.7044 V, for NCM-0.32 it is 0.415 V, and for NCM-0.40 it is 0.434 V. It can be seen that the potential differences for NCM-0.24 and NCM-0.40 are greater than that for NCM-0.32, indicating that NCM-0.32 has better electrochemical polarization. However, the peak symmetry of NCM-0.32 is greater than that of NCM-0.24 but less than that of NCM-0.40. This indicates that with increasing titanium doping concentration, the reversibility of the redox reaction and the reaction kinetics also increase.

[0097] Figure 7-8 Impedance maps of NCM-0.24, NCM-0.32, and NCM-0.40 prepared in Examples 1-3 are shown. Figure 7 Before the loop, Figure 8After cycling, it can be seen that NCM-0.32 has the smallest circle radius and the smallest charge transfer resistance, indicating that the battery prepared with NCM-0.32 sample material has a lower charge transfer resistance and better electrochemical performance compared with the battery prepared with NCM-0.24 or NCM-0.40 sample materials.

[0098] The initial charge-discharge data at 0.1C for NCM-0.32 prepared in Example 1 and NCM-1.05 prepared in Comparative Example 1 are shown in Table 4. It can be seen that titanium doping increases the interlayer spacing between materials, and doping improves the coulombic efficiency of the materials.

[0099] Table 4

[0100]

[0101] The cycling performance data at 1C for NCM-0.32 prepared in Example 1 and NCM-1.05 prepared in Comparative Example 1 are shown in Table 5. It can be seen that Ti... 4+ The doping improves the stability of the material structure, thereby improving the material's cycle performance.

[0102] Table 5

[0103]

[0104] Figure 9 Table 6 shows the rate performance of NCM-0.32 prepared in Example 1 and NCM-1.05 prepared in Comparative Example 1. The data specifically represent the discharge specific capacity at 0.1C, 0.2C, 0.5C, 1C, 2C, and 5C, as well as the discharge specific capacity at 0.1C. It can be seen that the structure of the undoped material collapses at 5C, reducing the material's discharge specific capacity. 4+ Doping of materials can enhance the stability of ternary cathode materials at high rates and improve the rate performance of the materials.

[0105] Table 6

[0106]

[0107] Table 7 shows the first charge-discharge data at 0.1C for the doped and modified ternary cathode materials prepared in Examples 1, 4-9.

[0108] Table 7

[0109]

[0110] Table 8 shows the cycling performance data of the doped and modified ternary cathode materials prepared in Examples 1, 4-9 at 1C.

[0111] Table 8

[0112]

[0113] The rate performance data of the doped modified ternary cathode materials prepared in Examples 1, 4-9 are shown in Table 9, specifically the discharge specific capacity at 0.1C, 0.2C, 0.5C, 1C, 2C, and 5C, and finally the discharge specific capacity at 0.1C.

[0114] Table 9

[0115]

[0116] In summary, the present invention, by doping high-nickel ternary materials with appropriate amounts of Ti and V, exhibits a synergistic effect, thereby improving the electrochemical performance of the materials. The electrochemical performance of NCM-Ti-V prepared in Example 5 is superior to that of Example 1 (NCM-0.32) and Example 4 (NCM-0.73). The present invention further improves the electrochemical performance of materials by modifying TiO2 and V2O5, with NCM-1 in Example 6 showing the best coulombic efficiency, cycle performance, and rate performance.

[0117] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for preparing a doped and modified ternary cathode material, characterized in that, Includes the following steps: Step 1: Ni 0.8 Co 0.1 Mn 0.1 (OH)₂, lithium hydroxide, titanium dioxide, and vanadium pentoxide are mixed and ground to form a mixture; wherein, the titanium dioxide and the Ni 0.8 Co 0.1 Mn 0.1 The molar ratio of (OH)₂ is 0.001~0.005:1, and the vanadium pentoxide and Ni 0.8 Co 0.1 Mn 0.1 The molar ratio of (OH)₂ is 0.001~0.005:1; Step 2: The mixture is calcined in stages in an oxygen atmosphere, ground and sieved to obtain the doped and modified ternary cathode material; In step one, before adding titanium dioxide and vanadium pentoxide, the titanium dioxide and vanadium pentoxide are modified, including the following steps: S11. Mix TiO2 and V2O5 in a molar ratio of 1~5:1~5, add to deionized water, stir evenly, then add polyethylene glycol 400, stir evenly to obtain a dispersion. S12. Add acrylamide and ammonium persulfate to the dispersion, react at 60~90℃ for 4~8h, filter, wash with anhydrous ethanol, and dry under vacuum to obtain product A; S13. Add the silane coupling agent to anhydrous ethanol to prepare a silane coupling agent solution with a concentration of 1~10wt%. Mix product A with the silane coupling agent solution, heat to 60~80℃ and stir for 1~3h. Filter, wash with anhydrous ethanol and deionized water in sequence, and dry under vacuum to obtain modified TiO2 and V2O5.

2. The method for preparing a doped and modified ternary cathode material as described in claim 1, characterized in that, In step one, Ni 0.8 Co 0.1 Mn 0.1 The molar ratio of (OH)2 to lithium hydroxide is 1:1.03~1.

07.

3. The method for preparing a doped and modified ternary cathode material as described in claim 1, characterized in that, In step two, the specific steps of segmented calcination are as follows: at a certain heating rate, the temperature is raised to 100~200℃ and held for 0.2~1 h, then raised to 450~550℃ and held for 3~7 h, then raised to 800~900℃ and held for 3~7 h, then lowered to 750~800℃ at a certain cooling rate and held for 8~12 h, and finally lowered to 100~200℃.

4. The method for preparing a doped and modified ternary cathode material as described in claim 3, characterized in that, The heating rate is 2~4℃ / min, and the cooling rate is 1~3℃ / min.

5. The method for preparing a doped and modified ternary cathode material as described in claim 1, characterized in that, In S11, the mass ratio of the total mass of TiO2 and V2O5, the mass of deionized water, and the mass of polyethylene glycol 400 is 1:10~50:0.1~0.

3.

6. The method for preparing a doped and modified ternary cathode material as described in claim 1, characterized in that, In S12, the total mass ratio of TiO2 and V2O5 to acrylamide is 1:0.1~2; the mass ratio of acrylamide to ammonium persulfate is 5~20:0.

1. In S13, the mass ratio of product A to silane coupling agent solution is 1:3~8.

7. A doped and modified ternary cathode material, characterized in that, It is prepared by the method for preparing doped and modified ternary cathode material according to any one of claims 1-6.

8. A battery, characterized in that, The positive electrode material of the battery is the doped and modified ternary positive electrode material as described in claim 7.

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