One-dimensional LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 ternary layered oxide cathode material and its preparation method

Abstract

The application belongs to the technical field of lithium ion batteries, and particularly relates to a kind of one-dimensional LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 ternary layered oxide positive electrode material and a preparation method thereof, which comprises the following steps: adding a nickel salt, a cobalt salt and a manganese salt into water, stirring and dissolving to obtain a solution A; adding LiMn2O4 into the solution A and stirring uniformly to obtain a solution B; mixing a lithium salt with water to obtain a solution C, and under stirring, adding the solution C into the solution B to obtain a solution D; evaporating the solution D under stirring to obtain a precursor powder; and sintering the precursor powder at 400-600 DEG C, and then sintering at 750-850 DEG C to obtain the positive electrode material. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 material.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology, specifically relating to a type of one-dimensional LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 ternary layered oxide cathode material and its preparation method. Background Technology

[0002] Facing the significant energy storage application demands in multiple fields such as power batteries, electronic devices, mobile communications, and even grid energy storage, current energy conversion and storage technologies and devices are facing increasingly higher challenges. Developing lithium-ion battery devices and energy storage technologies is key to addressing these demands. However, while current cathode materials (such as LiCoO2, LiMn2O4, or LiFePO4) have achieved widespread application, their energy density and power density are relatively low, failing to meet the ever-increasing demands for high energy and high power. Therefore, developing high-energy-density and high-power-density energy storage technologies is urgently needed. As is well known, cathode materials are crucial to the performance of lithium-ion batteries; therefore, the key to developing high-energy-density and high-power-density energy storage technologies lies in developing high-performance cathode materials. Compared to unary and binary cathode materials, ternary electrodes have higher energy storage potential. Among them, LiNi... 1 / 3 Co 1 / 3 Mn 1 / 3 O2 is a layered transition metal oxide with advantages such as high reversibility, high energy density, moderate voltage platform, good thermal stability, and low price, which has attracted widespread attention from academia and industry.

[0003] LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 Although O2 has many advantages, under high-power charge and discharge conditions, LiNi 1 / 3 Co 1 / 3Mn 1 / 3 The cycling performance of LiNi deteriorates rapidly, and the morphology of the electrode material undergoes drastic changes during cycling, which severely limits the development of LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 Application of O2 in high power density and high energy density energy storage devices.

[0004] Existing technologies typically employ doping, coating, and other methods to treat LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 materials were modified. These methods, although effective for LiNi... 1 / 3 Co 1 / 3 Mn 1 / 3O2 materials offer some improvement in electrochemical performance, but none of them can completely solve the problem of LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 materials face challenges in high-power charging and discharging. Micro / nano structure design of electrode materials is an effective measure to improve their rate performance. However, this is limited by LiNi... 1 / 3 Co 1 / 3 Mn 1 / 3 Due to the high sintering temperature and inherent complexity of O2 materials, common preparation methods struggle to effectively synthesize LiNi with complex micro / nano structures. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 materials severely limit LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 Application of O2 materials in high-power energy storage devices. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a class of one-dimensional LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 ternary layered oxide cathode material and its preparation method: This invention uses LiMn2O4 nanorods or nanotubes as high-temperature templates and employs template methods or sacrificial template methods, through a combination of various processes, to smoothly transition the micro / nano structure of the precursor template to LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 In O2 materials, LiNi with a one-dimensional structure was prepared. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 materials.

[0006] The present invention is specifically implemented through the following technical solution.

[0007] The first objective of this invention is to provide a class of one-dimensional LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 The method for preparing O2 ternary layered oxide cathode material is characterized by comprising the following steps:

[0008] S1. Add nickel salt and cobalt salt to deionized water, stir to dissolve, and obtain solution A;

[0009] S2. LiMn2O4, which serves as a one-dimensional solid template and manganese source, is added to solution A and stirred until homogeneous to obtain solution B.

[0010] S3. The lithium salt, which serves as both a lithium source and a complexing agent, is mixed with deionized water to obtain solution C. Under continuous stirring, solution C is added to solution B to obtain solution D.

[0011] S4. Under continuous stirring, solution D is evaporated at a constant temperature, so that the water in the solvent evaporates slowly, and a uniformly mixed precursor powder is obtained.

[0012] S5. The precursor powder prepared in S4 is sintered at a low temperature of 400–600 °C, followed by high temperature sintering at 750–850 °C to obtain one-dimensional LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 ternary layered oxide cathode material.

[0013] In a preferred embodiment of the present invention, the LiMn2O4 serving as a one-dimensional solid template and manganese source is a LiMn2O4 nanorod or a LiMn2O4 nanotube.

[0014] In a preferred embodiment of the present invention, when the molar ratio of LiMn2O4 nanorods or LiMn2O4 nanotubes, nickel salt, cobalt salt, lithium salt, and manganese salt is 0.5:1:1:(2.75~2.875):0, the product prepared by S5 is single-phase LiNi. 1 / 3Co 1 / 3 Mn 1 / 3 O2 nanorod active cathode materials or single-phase LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 Porous nanotube active cathode material.

[0015] In a preferred embodiment of the present invention, when the molar ratio of LiMn2O4 nanorods or LiMn2O4 nanotubes, nickel salt, cobalt salt, manganese salt, and lithium salt is (0.33–0.40):1:1:1:(3.20–3.45), the product prepared in S5 is LiMn2O4@LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 composite nanorod active cathode materials, or LiMn2O4@LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 composite porous nanotube active cathode material.

[0016] In a preferred embodiment of the present invention, the nickel salt is nickel sulfate, nickel carbonate, or nickel nitrate; the manganese salt is manganese nitrate, manganese sulfate, or manganese carbonate; the cobalt salt is cobalt nitrate, cobalt sulfate, or cobalt carbonate; and the lithium salt is lithium hydroxide, lithium nitrate, or lithium carbonate.

[0017] In a preferred embodiment of the present invention, in S4, the temperature of constant-temperature evaporation is 60-80°C.

[0018] In a preferred embodiment of the present invention, in S5, the atmosphere used for low-temperature sintering is argon or nitrogen, and the low-temperature sintering time is 3-5 hours; the high-temperature sintering atmosphere is oxygen or air, and the high-temperature sintering time is 8-10 hours.

[0019] A second objective of this invention is to provide a one-dimensional LiNi prepared by the above-described preparation method. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 ternary layered oxide cathode material.

[0020] In a preferred embodiment of the present invention, the positive electrode material is a nanorod or porous nanotube structure;

[0021] The nanorod structure is a single-phase LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 nanorods or LiMn2O4@LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 composite nanorods; porous nanotube structure of single-phase LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 Porous nanotubes or LiMn2O4@LiNi 1 / 3 Co 1 / 3 Mn 1 / 3O2 composite porous nanotubes.

[0022] The third objective of this invention is to provide the aforementioned one-dimensional LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 The application of O2 ternary layered oxide cathode material in lithium-ion batteries, wherein the lithium-ion batteries are prepared according to the following steps:

[0023] The positive electrode material, conductive agent, binder, and dispersant are dispersed in the dispersant, and then the dispersion is applied to the current collector using a spin coating process. After drying, it is cut for later use. Subsequently, the button battery sample is assembled in the order of positive electrode housing, positive electrode, separator, negative electrode, electrolyte, and negative electrode housing.

[0024] The weight ratio of the positive electrode material, conductive agent, and binder is 7:2:1; the dispersant is NMP; the current collector is Al foil; and the drying conditions are: vacuum, 100℃ for 10-12 hours.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] 1. High energy density and high power density performance have always been core requirements for the design of energy storage devices, especially for LiNi. 1 / 3Co 1 / 3 Mn 1 / 3 Addressing the poor high-power charge / discharge performance of O2 materials, improving their rate performance through micro / nano structure design is a feasible approach. Therefore, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 The design and fabrication of micro / nano structures for O2 materials has always been a cutting-edge academic challenge, attracting widespread attention and research. However, the high sintering temperature of electrode materials and the complex phase structure of the materials have resulted in very slow progress in this area.

[0027] To overcome this challenge, this invention uses LiMn2O4 nanorods or nanotubes as high-temperature templates and employs template methods or sacrificial template methods, combined with various processes, to smoothly transition the micro / nano structure of the precursor template to LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 In O2 materials, four one-dimensional LiNi structures were prepared by adjusting the amount of raw materials. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 materials provide valuable insights and approaches for research in this field.

[0028] 2. Using the method of this invention to process LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 materials, designed as one-dimensional nanorods or porous nanotube structures, can effectively shorten the migration path of lithium ions and enhance lithium ion transport kinetics, thus enabling LiNi... 1 / 3 Co 1 / 3 Mn 1 / 3 O2 materials have improved both rate performance and initial coulombic efficiency, significantly enhancing their application value in high-power energy storage devices.

[0029] 3. A type of one-dimensional LiNi was prepared using the method of this invention. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 materials include four types of active cathode materials: LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 nanorod active cathode material, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 Porous nanotube active cathode material, LiMn2O4@LiNi 1 / 3 Co 1 / 3 Mn 1 / 3O2 composite nanorod active cathode materials, and LiMn2O4@LiNi 1 / 3 Co 1 / 3 Mn 1 / 3O2 composite porous nanotube active cathode material. Compared with LiNi prepared by solid-phase or general liquid-phase methods. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 materials, using the preparation method of this invention, can realize LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 One-dimensional structural design of O2 materials. Benefiting from the unique micro / nano structure morphology, one-dimensional LiNi... 1 / 3 Co 1 / 3 Mn 1 / 3 O2 materials have a higher specific surface area and thus higher electrochemical activity, especially LiNi with a hierarchical structure design. 1 / 3 Co 1 / 3 Mn 1 / 3 Porous nanotubes, with their abundant structural pores, can somewhat mitigate the large volume changes during lithium insertion / extraction, and can significantly improve the performance of LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 Rate performance of O2 materials.

[0030] 4. With single-phase LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 Compared to O2 materials, LiMn2O4@LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 composite electrode materials also exhibit a higher discharge platform (3.7V). By adjusting the composite ratio of the two phases, electrode materials with higher energy density can be obtained to a certain extent.

[0031] 5. The one-dimensional LiNi developed in this invention 1 / 3 Co 1 / 3 Mn 1 / 3 The method for preparing O2 materials is simple, environmentally friendly, and synthesizes LiNi with a one-dimensional micro / nano structure. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 materials have high yield, are easy to promote, and are suitable for large-scale production. Attached Figure Description

[0032] Figure 1 LiNi as in Example 1 1 / 3 Co 1 / 3 Mn 1 / 3 Scanning electron microscope (SEM) image of O2 nanorods.

[0033] Figure 2 LiNi of Example 3 1 / 3 Co 1 / 3 Mn 1 / 3 Scanning electron microscope (SEM) image of O2 porous nanotubes.

[0034] Figure 3 LiNi as in Example 1 1 / 3 Co 1 / 3 Mn 1 / 3 O2 nanorods and LiNi from Example 3 1 / 3 Co 1 / 3 Mn 1 / 3 X-ray diffraction pattern of O2 porous nanotubes.

[0035] Figure 4 LiNi in Example 1 1 / 3 Co 1 / 3 Mn 1 / 3 O2 nanorods and LiNi in Example 3 1 / 3 Co 1 / 3 Mn 1 / 3 Charge-discharge cycle rate plots of two O2 porous nanotube samples. Detailed Implementation

[0036] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention.

[0037] Unless otherwise specified, the experimental and detection methods described in the following embodiments are conventional methods; unless otherwise specified, the reagents and materials are commercially available.

[0038] High energy density and high power density performance have always been core requirements for the design of energy storage devices, especially for LiNi. 1 / 3Co 1 / 3 Mn 1 / 3 Addressing the poor high-power charge / discharge performance of O2 materials, improving their rate performance through micro / nano structure design is a feasible approach. Therefore, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 The design and fabrication of micro / nano structures for O2 materials has always been a cutting-edge academic challenge, attracting widespread attention and research. However, the high sintering temperatures of electrode materials and the complex phase structures of these materials have resulted in very slow progress in this area. To overcome this challenge, this invention uses LiMn2O4 nanorods or nanotubes as high-temperature templates and employs template methods or sacrificial template methods, combined with various processes, to smoothly transition the precursor template's micro / nano structure to LiNi. 1 / 3 Co1 / 3 Mn 1 / 3 In O2 materials, four one-dimensional LiNi structures were prepared by adjusting the amount of raw materials. 1 / 3Co 1 / 3 Mn 1 / 3 O2 materials provide valuable insights and approaches for research in this field.

[0039] The specific preparation method includes the following steps:

[0040] S1. Add nickel salt, cobalt salt, and manganese salt to water and stir to dissolve, to obtain solution A;

[0041] S2. LiMn2O4, which serves as a one-dimensional solid template and manganese source, is added to solution A and stirred until homogeneous to obtain solution B.

[0042] S3. The lithium salt, which serves as both a lithium source and a complexing agent, is mixed with water to obtain solution C. Under continuous stirring, solution C is added to solution B to obtain solution D.

[0043] S4. Under continuous stirring, solution D is evaporated at a constant temperature to obtain a uniformly mixed precursor powder.

[0044] S5. Under a protective gas atmosphere, the precursor powder prepared in S4 is sintered at 400–600 °C to fully decompose the inorganic salts in the precursor; then, after sintering in an oxygen-containing gas atmosphere at 750–850 °C, one-dimensional LiNi is obtained. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 ternary layered oxide cathode material.

[0045] In this invention, the LiMn2O4 used as a one-dimensional solid template and manganese source is a LiMn2O4 nanorod or a LiMn2O4 nanotube.

[0046] When the molar ratio of LiMn2O4 nanorods or LiMn2O4 nanotubes, nickel salt, cobalt salt, lithium salt, and manganese salt is 0.5:1:1:(2.75~2.875):0, the product prepared by S5 is single-phase LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 nanorod active cathode materials or single-phase LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 Porous nanotube active cathode material.

[0047] When the molar ratio of LiMn2O4 nanorods or LiMn2O4 nanotubes, nickel salt, cobalt salt, manganese salt, and lithium salt is (0.33–0.40):1:1:1:(3.20–3.45), the product prepared by S5 is LiMn2O4@LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 composite nanorod active cathode materials, or LiMn2O4@LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 composite porous nanotube active cathode material.

[0048] When the prepared product is a single-phase nanorod or porous nanotube, no additional manganese salt is required. However, when the prepared product is a composite nanorod or porous nanotube, additional manganese salt is required.

[0049] In this invention, the nickel salt is nickel sulfate, nickel carbonate, or nickel nitrate; the manganese salt is manganese nitrate, manganese sulfate, or manganese carbonate; the cobalt salt is cobalt nitrate, cobalt sulfate, or cobalt carbonate; and the lithium salt is lithium hydroxide, lithium nitrate, or lithium carbonate.

[0050] Using prepared one-dimensional LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 The preparation of lithium-ion batteries using O2 ternary layered oxide cathode materials follows these steps:

[0051] The positive electrode material, conductive agent, binder, and dispersant are dispersed in the dispersant, and then the dispersion is applied to the current collector using a spin coating process. After drying, it is cut for later use. Subsequently, the button battery sample is assembled in the order of positive electrode housing, positive electrode, separator, negative electrode, electrolyte, and negative electrode housing.

[0052] The weight ratio of the positive electrode material, conductive agent, and binder is 7:2:1; the dispersant is NMP; the current collector is Al foil; and the drying conditions are: vacuum, 100℃ for 10-12 hours.

[0053] The present invention will be specifically described below through the following embodiments.

[0054] Example 1

[0055] This embodiment provides a LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 The specific steps for preparing O2 nanorod active cathode materials are as follows:

[0056] Step 1: Dissolve 1 mmol of nickel nitrate and 1 mmol of cobalt nitrate in 15 ml of deionized water to obtain solution A;

[0057] Step 2: Add 0.5 mmol of LiMn2O4 nanorod template to solution A and stir until homogeneous to obtain solution B in which the template is fully dispersed.

[0058] Step 3: Dissolve 2.875 mmol of lithium hydroxide in 15 ml of deionized water to obtain solution C; and under continuous stirring, slowly add solution C to solution B to obtain solution D;

[0059] Step 5: While maintaining continuous stirring, evaporate solution D at a constant temperature of 70°C to allow the water in the solvent to evaporate slowly, resulting in a uniformly mixed precursor powder.

[0060] Step six: First, the precursor powder is sintered at a low temperature in an argon atmosphere at 500℃ for 4 hours to allow for the complete decomposition of the inorganic salts in the precursor. Then, it is sintered at a high temperature in an oxygen atmosphere at 800℃ for 8 hours to obtain LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 nanorod active cathode material.

[0061] Example 2

[0062] This embodiment provides a LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 The specific steps for preparing O2 nanorod active cathode materials are as follows:

[0063] Step 1: Dissolve 2 mmol of nickel carbonate and 2 mmol of cobalt carbonate in 20 ml of deionized water to obtain solution A;

[0064] Step 2: Add 1 mmol of LiMn2O4 nanorod template to solution A and stir until homogeneous to obtain solution B in which the template is fully dispersed.

[0065] Step 3: Dissolve 5.75 mmol of lithium hydroxide in 20 ml of deionized water to obtain solution C; and under continuous stirring, slowly add solution C to solution B to obtain solution D;

[0066] Step 5: While maintaining continuous stirring, evaporate solution D at a constant temperature of 80°C to allow the water in the solvent to evaporate slowly, resulting in a uniformly mixed precursor powder.

[0067] Step six: First, the precursor powder is sintered at a low temperature in an argon atmosphere at 500℃ for 4 hours to allow for the complete decomposition of the inorganic salts in the precursor. Then, it is sintered at a high temperature in an oxygen atmosphere at 800℃ for 9 hours to obtain LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 nanorod active cathode material.

[0068] Example 3

[0069] This embodiment provides a LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 The specific steps for preparing O2 porous nanotube active cathode materials are as follows:

[0070] Step 1: Dissolve 1 mmol of nickel nitrate and 1 mmol of cobalt nitrate in 15 ml of deionized water to obtain solution A;

[0071] Step 2: Add 0.5 mmol of LiMn2O4 nanotube template to solution A and stir until homogeneous to obtain solution B in which the template is fully dispersed.

[0072] Step 3: Dissolve 2.875 mmol of lithium hydroxide in 15 ml of deionized water to obtain solution C; and under continuous stirring, slowly add solution C to solution B to obtain solution D;

[0073] Step 4: While maintaining continuous stirring, evaporate solution D at a constant temperature of 70°C to allow the water in the solvent to evaporate slowly, resulting in a uniformly mixed precursor powder.

[0074] Step 5: First, the precursor powder is sintered at a low temperature in an argon atmosphere at 500℃ for 4 hours to allow for the complete decomposition of the inorganic salts in the precursor. Then, it is sintered at a high temperature in an oxygen atmosphere at 800℃ for 8 hours to obtain LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 porous nanotube active cathode material.

[0075] Example 4

[0076] This embodiment provides a LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 The specific steps for preparing O2 porous nanotube active cathode materials are as follows:

[0077] Step 1: Dissolve 2 mmol of nickel carbonate and 2 mmol of cobalt carbonate in 20 ml of deionized water to obtain solution A;

[0078] Step 2: Add 1 mmol of LiMn2O4 nanotube template to solution A and stir until homogeneous to obtain solution B in which the template is fully dispersed.

[0079] Step 3: Dissolve 5.75 mmol of lithium hydroxide in 20 ml of deionized water to obtain solution C; and under continuous stirring, slowly add solution C to solution B to obtain solution D;

[0080] Step 4: While maintaining continuous stirring, evaporate solution D at a constant temperature of 80°C to allow the water in the solvent to evaporate slowly, resulting in a uniformly mixed precursor powder.

[0081] Step 5: First, the precursor powder is sintered at a low temperature in an argon atmosphere at 500℃ for 4 hours to allow for the complete decomposition of the inorganic salts in the precursor. Then, it is sintered at a high temperature in an oxygen atmosphere at 800℃ for 9 hours to obtain LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 porous nanotube active cathode material.

[0082] Example 5

[0083] This embodiment provides a LiMn2O4@LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 The specific steps for preparing O2 composite nanorod active cathode materials are as follows:

[0084] Step 1: Dissolve 1 mmol nickel nitrate, 1 mmol cobalt nitrate, and 1 mmol manganese nitrate in 15 ml of deionized water to obtain solution A;

[0085] Step 2: Add 0.35 mmol of LiMn2O4 nanorod template to solution A and stir until homogeneous to obtain solution B in which the template is fully dispersed.

[0086] Step 3: Dissolve 3.241 mmol of lithium nitrate in 15 ml of deionized water to obtain solution C; and under continuous stirring, slowly add solution C to solution B to obtain solution D;

[0087] Step 4: While maintaining continuous stirring, evaporate solution D at a constant temperature of 70°C to allow the water in the solvent to evaporate slowly, resulting in a uniformly mixed precursor powder.

[0088] Step 5: First, the precursor powder is sintered at a low temperature in an argon atmosphere at 500℃ for 4 hours to allow for the complete decomposition of the inorganic salts in the precursor. Then, it is sintered at a high temperature in an oxygen atmosphere at 800℃ for 8 hours to obtain LiMn2O4@LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 composite porous nanorod active cathode material.

[0089] Example 6

[0090] This embodiment provides a LiMn2O4@LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 The specific steps for preparing O2 composite porous nanotube active cathode materials are as follows:

[0091] Step 1: Dissolve 1 mmol nickel nitrate, 1 mmol cobalt nitrate, and 1 mmol manganese nitrate in 15 ml of deionized water to obtain solution A;

[0092] Step 2: Add 0.35 mmol of LiMn2O4 nanotube template to solution A and stir until homogeneous to obtain solution B in which the template is fully dispersed.

[0093] Step 3: Dissolve 3.241 mmol of lithium nitrate in 15 ml of deionized water to obtain solution C; and under continuous stirring, slowly add solution C to solution B to obtain solution D;

[0094] Step 4: While maintaining continuous stirring, evaporate solution D at a constant temperature of 70°C to allow the water in the solvent to evaporate slowly, resulting in a uniformly mixed precursor powder.

[0095] Step 5: First, the precursor powder is sintered at a low temperature in an argon atmosphere at 500℃ for 4 hours to allow for the complete decomposition of the inorganic salts in the precursor. Then, it is sintered at a high temperature in an oxygen atmosphere at 800℃ for 8 hours to obtain LiMn2O4@LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 composite porous nanotube active cathode material.

[0096] Referring to the accompanying drawings, Examples 1 and 3 illustrate the preparation of a LiNi alloy. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 nanorod active cathode material and LiNi 1 / 3 Co 1 / 3Mn 1 / 3 Performance of porous nanotube active cathode materials.

[0097] Figure 1 LiNi prepared in Example 1 1 / 3 Co 1 / 3 Mn 1 / 3 Scanning electron microscope (SEM) image of O2 nanorod active cathode material. The image clearly shows that LiNi... 1 / 3 Co 1 / 3 Mn 1 / 3 The O2 active cathode material exhibits a typical one-dimensional rod-like structure at the nanoscale, with the nanorods having a diameter of 200-500 nm and a length of 2-5 μm.

[0098] Figure 2 LiNi prepared in Example 3 1 / 3 Co 1 / 3 Mn 1 / 3 Scanning electron microscope (SEM) images of porous nanotube active cathode materials clearly show that LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 The active cathode material exhibits a typical one-dimensional tubular structure at the nanoscale, with nanotubes ranging from 500-800 nm in diameter and 5-10 μm in length. Furthermore, at even smaller scales, it can be clearly observed that the nanotubes are composed of stacked even smaller nanoparticles, with abundant mesoporous pores between them, which makes LiNi... 1 / 3 Co 1 / 3 Mn 1 / 3 Active cathode materials possess multi-scale hierarchical structures, and when used as cathode materials for lithium-ion batteries, they will exhibit superior electrochemical performance.

[0099] pass Figure 1 and Figure 2 This demonstrates that one-dimensional rod-shaped or one-dimensional tubular LiNi structures can be prepared using LiMn2O4 nanorods or nanotubes as templates. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 active cathode material, realizing the LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 Micro-nano structure design of O2 materials.

[0100] Figure 3 The LiNi prepared in Example 1 1 / 3 Co 1 / 3 Mn 1 / 3 O2 nanorods and LiNi prepared in Example 3 1 / 3 Co 1 / 3Mn1 / 3 X-ray diffraction patterns of two porous nanotube active cathode material samples. The vertical axis represents X-ray intensity in au; the horizontal axis represents twice the diffraction angle (2-θ) in degrees. Figure 4 It can be seen that the X-ray diffraction pattern shapes of the samples in Example 1 and Example 3 are consistent, indicating that the LiNi prepared by these two methods... 1 / 3 Co 1 / 3 Mn 1 / 3 O2 has the same phase, all pointing to the α-NaFeO2 phase.

[0101] Figure 4 The LiNi prepared in Example 1 1 / 3 Co 1 / 3 Mn 1 / 3 O2 nanorods and LiNi prepared in Example 3 1 / 3 Co 1 / 3Mn 1 / 3 Charge-discharge cycle rate plots of two porous nanotube active cathode material samples. The horizontal axis represents the number of cycles, in units of revolutions; the vertical axis represents the specific capacity of the material, in units of mAh / g. Figure 4 It can be seen that LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 nanorods and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 Both porous nanotube electrode materials exhibited excellent rate performance, with LiNi showing superior performance under high current density charge-discharge of 5C. 1 / 3 Co 1 / 3 Mn 1 / 3 The discharge capacities of O2 nanorods and porous nanotubes are 102 mAh / g and 126 mAh / g, respectively. (Compared to LiNi...) 1 / 3 Co 1 / 3 Mn 1 / 3 Compared to O2 nanorods, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 porous nanotubes exhibit superior rate performance, thanks to LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 The hierarchical structure design of O2 porous nanotube electrode materials effectively buffers the large volume changes during lithium insertion / extraction, while also providing multiple channels for lithium-ion transport. This effectively reduces the lithium-ion transport distance, improves electrode reaction kinetics, and significantly enhances rate performance, providing up to 126 mAh g⁻¹ at a 5C charge / discharge rate. -1 Its specific capacity is superior to that of traditional LiNi. 1 / 3 Co1 / 3 Mn 1 / 3 O2 materials (LiNi prepared by solid-phase method or general liquid-phase method) 1 / 3 Co 1 / 3 Mn 1 / 3 Performance of O2 material (5C charge / discharge rate less than or equal to 120mAh g) -1 ).

[0102] In addition, with single-phase LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 Compared to the O2 composite porous nanotube material (discharge plateau voltage 3.6V), the LiMn2O4@LiNi in Example 6... 1 / 3 Co 1 / 3 Mn 1 / 3 The O2 composite porous nanotube electrode material (discharge plateau voltage 3.7V) also exhibits a higher discharge plateau. By adjusting the composite ratio of the two phases, electrode materials with higher energy density can be obtained to a certain extent.

[0103] The performance of Example 2 is similar to that of Example 1, and the performance of Example 4 is similar to that of Example 3, so it will not be described in detail.

[0104] The above description is merely a preferred embodiment of the present invention and does not limit the invention in any way. Although the present invention has been described in detail and some optimal specific experimental examples have been cited, it is obvious to those skilled in the art that various modifications, alterations, or alternatives can be made based on the above description. For example, in addition to manganese nitrate and manganese sulfate, other salts such as manganese carbonate can be used to replace the manganese raw material in the experiment; the complexing agent is not limited to lithium hydroxide and can be replaced by other complexing agents; changes in sintering atmosphere, temperature, and time, etc., should all be included within the scope of protection of the claims.

[0105] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, it is intended to include any modifications and variations that fall within the scope of the claims and their equivalents.

Claims

1. A class of one-dimensional LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 The method for preparing O2 ternary layered oxide cathode material is characterized by: Includes the following steps: S1. Add nickel salt, cobalt salt and manganese salt to water, stir to dissolve, and obtain solution A; S2. LiMn2O4, which serves as a one-dimensional solid template and manganese source, is added to solution A and stirred until homogeneous to obtain solution B. S3. The lithium salt, which serves as both a lithium source and a complexing agent, is mixed with water to obtain solution C. Under continuous stirring, solution C is added to solution B to obtain solution D. S4. Under continuous stirring, solution D is evaporated at a constant temperature to obtain a uniformly mixed precursor powder. S5. Under a protective gas atmosphere, the precursor powder is sintered at 400~600 °C, followed by sintering in an oxygen-containing gas atmosphere at 750~850 °C to obtain one-dimensional LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 ternary layered oxide cathode material; The LiMn2O4 used as a one-dimensional solid template and manganese source is either a LiMn2O4 nanorod or a LiMn2O4 nanotube. When the molar ratio of LiMn2O4 nanorods, nickel salt, cobalt salt, lithium salt, and manganese salt is 0.5:1:1:(2.75~2.875):0, the product prepared by S5 is single-phase LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 nanorods; When the molar ratio of LiMn2O4 nanotubes, nickel salt, cobalt salt, manganese salt, and lithium salt is (0.33~0.40):1:1:1:(3.20~3.45), the product prepared by S5 is LiMn2O4@LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 composite porous nanotubes; In S5, the protective gas atmosphere is argon or nitrogen, and the sintering time is 3-5 h at 400~600 ℃; the oxygen-containing gas atmosphere is oxygen or air, and the sintering time is 8-10 h at 750~850 ℃.

2. The preparation method according to claim 1, characterized in that, Nickel salts are nickel sulfate, nickel carbonate, or nickel nitrate; manganese salts are manganese nitrate, manganese sulfate, or manganese carbonate; cobalt salts are cobalt nitrate, cobalt sulfate, or cobalt carbonate; lithium salts are lithium hydroxide, lithium nitrate, or lithium carbonate.

3. The preparation method according to claim 1, characterized in that, In S4, the temperature for isothermal evaporation is 60~80 ℃.

4. One-dimensional LiNi prepared by the preparation method according to any one of claims 1-3 1 / 3 Co 1 / 3 Mn 1 / 3 O2 ternary layered oxide cathode material.

5. The one-dimensional LiNi according to claim 4 1 / 3 Co 1 / 3 Mn 1 / 3 O2 ternary layered oxide cathode material, characterized in that... The positive electrode material is a nanorod or porous nanotube structure; The nanorod structure is a single-phase LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 nanorods; porous nanotube structure is LiMn2O4@LiNi 1 / 3Co 1 / 3 Mn 1 / 3 O2 composite porous nanotubes.

6. A lithium-ion battery, characterized in that, The positive electrode material in the lithium-ion battery is the one-dimensional LiNi as described in claim 5. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 ternary layered oxide cathode material.

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