Preparation method of nano-composite zirconium dioxide and ternary lithium battery positive electrode material containing nano-composite zirconium dioxide

Abstract

The invention provides a preparation method of nano-composite zirconium dioxide and a ternary lithium battery positive electrode material containing the nano-composite zirconium dioxide. The nano-composite zirconium dioxide comprises powder 1 and powder 2, wherein the powder 1 is Ti and Nb doped zirconium dioxide powder; and the second powder body 2 is yttrium-doped zirconium dioxide powder. The ternary lithium battery positive electrode material containing the nano-composite zirconium dioxide is prepared by uniformly mixing a battery positive electrode material to be coated with the nano-composite zirconium dioxide powder, LiAlO2 powder and LiF powder and then calcining. The nano-composite zirconium dioxide prepared by the method has the characteristics of small particle size, high dispersity and stability at high temperature; the prepared ternary lithium battery positive electrode material has the characteristics of high conductivity, high cycle use discharge capacity retention rate and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium battery positive electrode material preparation, and in particular relates to a preparation method of nano-composite zirconium dioxide and a ternary lithium battery positive electrode material containing the same. Background Art

[0002] Lithium-ion batteries, due to their lightweight design, excellent cycle performance, and high energy density, are currently one of the most comprehensive battery systems. The energy density and capacity of lithium-ion batteries are largely determined by the cathode material used. Ternary cathode materials, due to their high specific capacity, excellent cycle stability, low cost, and safety, have become the preferred cathode material for next-generation lithium-ion batteries. However, they still suffer from serious issues such as high-voltage instability and flammability and explosiveness. To further improve the energy density, cycle performance, and thermal stability of lithium-ion batteries, appropriate modification of the cathode material is required to enhance its structural stability, discharge capacity, and recyclability.

[0003] In the field of new energy materials, nano-zirconia can be used as an additive for ternary lithium-ion battery cathode materials due to its nanoparticle size, uniform particle size distribution, lack of hard agglomerates, and good sphericity. It significantly improves the cycle performance and rate performance of lithium battery cathode materials such as lithium nickel cobalt manganese oxide, lithium cobalt oxide, and lithium manganese oxide. With its excellent thermal conductivity and chemical stability, nano-zirconia plays a key role in improving the thermal conductivity and corrosion resistance of cathode materials. By reducing the polarization and attenuation of the battery in high-temperature environments, it effectively enhances the stability of the battery and helps extend its service life. At the same time, the introduction of nano-zirconia can enhance the stability of the lattice structure. This lattice filling effect helps maintain the structural integrity of the cathode material during the charge and discharge cycle, thereby improving its cycle durability. In addition, the introduction of nano-zirconia can optimize the interface contact between the electrode and the electrolyte, reduce the internal resistance of the electrode, and increase the rate of charge transfer, thereby enhancing the battery's rapid charging and discharging capabilities under high current applications and improving its power output, which is specifically manifested as a higher discharge specific capacity. This may also be related to the miniaturization of the material particle size. The reduction in particle size promotes the embedding and de-embedding of lithium ions during the charging and discharging process, thereby optimizing the electrochemical response of the material.

[0004] Patent CN103523830A discloses a method for preparing a pure monoclinic single-species zirconium dioxide with a high specific surface area. This method involves pressurizing and heating an acidic solution containing zirconium ions at a pH less than 1 for a period of time to form monoclinic zirconium dioxide colloids or fine solid particles containing water of crystallization. The pH of the solution is then adjusted to alkaline, the zirconium dioxide colloids or fine solid particles are deposited, and the solution is washed multiple times to obtain a filter cake that is dried and calcined to ultimately obtain pure monoclinic zirconium dioxide. The introduction of ammonia as a precipitant during the experiment has adverse environmental impacts, and the specific surface area of the zirconium dioxide obtained by this method is not high enough, which limits its application in catalysts.

[0005] The main technical problems in the existing technology for preparing nano-composite zirconium dioxide and ternary lithium battery positive electrode materials containing it are: the crystal phase of zirconium dioxide is unstable, which easily leads to instability in the performance of the ternary lithium battery positive electrode material, etc., and the zirconium dioxide needs to be further doped, such as doping with elements such as yttrium oxide; zirconium oxide doped with yttrium oxide significantly improves the energy density, cycle life and safety of ternary lithium batteries by enhancing structural stability, interface protection and ion conduction, and is particularly suitable for high-voltage, high-nickel positive electrodes and solid-state battery systems. However, zirconium oxide doped with yttrium oxide has poor conductivity to lithium ions, and a high-impedance layer may be formed at the interface with the electrode material, reducing the effective conductivity and recycling performance of the ternary lithium battery positive electrode material. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides a preparation method of nano-composite zirconium dioxide and a ternary lithium battery positive electrode material containing the same. The prepared nano-composite zirconium dioxide has the characteristics of small particle size, high dispersibility and stability at high temperature. The ternary lithium battery positive electrode material containing the same has the characteristics of high electrical conductivity and high cycle discharge capacity retention rate.

[0007] The present invention prepares two doped nano zirconium dioxide powders by spray pyrolysis and hydrothermal method, and mixes them to obtain nano composite zirconium dioxide. Through microstructural complementarity and doping synergy, grain growth and phase change are suppressed at high temperature, significantly improving the thermal stability of nano ZrO2. In order to optimize the particle size and dispersibility of nano composite zirconium dioxide powder, HCl gas is introduced into the powder 1 preparation process to prevent the hydrolysis of the raw materials, and the surfactant polyvinyl pyrrolidone is added to reduce the surface tension of the solution and promote atomization to generate finer droplets, thereby obtaining zirconium dioxide powder 1 with small particle size and good dispersibility; after mixing with zirconium dioxide powder 2, the particle size and dispersibility of nano composite zirconium dioxide can be improved as a whole. The average particle size of the prepared nano composite zirconium dioxide is between 10-50nm, see the attached specification. Figure 1When preparing the positive electrode material of the ternary lithium battery, LiAlO2 and LiF are added to provide additional lithium ion channels, optimize the positive electrode-electrolyte interface, reduce the side reactions when coating the positive electrode material of the ternary lithium battery at high temperature, and improve the electrical performance and cycle stability of the material. In addition, since LiAlO2 and LiF are both insulators, excessive addition will reduce the overall electronic conductivity of the coating layer, resulting in increased electrode polarization. Therefore, during the preparation of zirconium dioxide powder 1, Nb-TiO2 is doped to form ZrO2-Nb-TiO2 nanopowder, and TiO2 is added at high temperature. 4+ and Nb 5+ Replace Zr 4+ , forming a (Zr, Ti, Nb)O2 solid solution and generating oxygen vacancies to improve the ionic conductivity of the material; Nb 5+ d 0 The electronic configuration can also enhance the n-type semiconductor properties and electronic conductivity.

[0008] In order to achieve the above objectives, the following technical solutions are adopted:

[0009] A nano-composite zirconium oxide comprises a powder 1 and a powder 2, wherein the powder 1 is a zirconium dioxide powder doped with Nb and Ti, and the powder 2 is a zirconium dioxide powder doped with yttrium.

[0010] Furthermore, the mass ratio of the powder 1 to the powder 2 is 10:1-1:10, preferably 4:6-3:7.

[0011] Furthermore, the powder 1 is prepared by a pyrolysis method, and the powder 2 is prepared by a hydrothermal method.

[0012] Furthermore, the preparation conditions of the powder 1 are as follows: ZrCl4 is dissolved in a mixture of ethanol and acetone, Ti(OEt)4 and NbCl5 are added and stirred to dissolve; HCl gas is introduced, polyvinyl pyrrolidone is added, and the mixture is stirred to obtain a precursor solution; the precursor solution is then injected into a spray pyrolysis device, pyrolyzed at 1000-1500°C for 10-15s, preferably at 1000-1200°C for 10-12s, cooled, and filtered to obtain powder 1;

[0013] The preparation conditions of the powder 2 are as follows: ZrOCl2·8H2O and Y(NO3)3·6H2O are dissolved in deionized water to prepare solution 1; glycine / KCl is added to the ammonia water and stirred to prepare solution 2; solution 2 is added to solution 1 while stirring to form a mixed solution, the mixed solution is subjected to a hydrothermal reaction at 160-200°C, and after the reaction, centrifugation, washing, and vacuum drying are performed to obtain powder 2.

[0014] Furthermore, the K value of the polyvinyl pyrrolidone in the preparation of powder 1 ranges from K12 to K30.

[0015] Furthermore, the preparation conditions of the powder 1 are as follows: 20-40 parts by weight, preferably 20-30 parts by weight, of ZrCl4 are dissolved in a mixture of ethanol and acetone in a volume ratio of 1:1-3, the amount ratio of ZrCl4 to the mixture of ethanol and acetone is 20-40g:70-120mL, 1-5 parts by weight, preferably 1-3 parts by weight of Ti(OEt)4 and 0.1-3 parts by weight, preferably 0.1-1 parts by weight of NbCl5 are added, and the mixture is stirred and dissolved at 40-60°C; HCl gas is slowly introduced for 2 minutes. 0-70mL, 1-10 parts by weight, preferably 2-5 parts by weight, of polyvinyl pyrrolidone are added and stirred evenly to obtain a precursor solution; then, at an air flow rate of 3-7L / min and an oxygen pressure of 150-200KPa, a hydrogen flow rate is fed at a rate of 3-7mL / min, and the precursor solution is injected into a flame spray pyrolysis device by a syringe pump, and pyrolyzed at 1000-1500°C for 10-15s, preferably at 1000-1200°C for 10-12s, rapidly cooled, and filtered to obtain powder 1.

[0016] Furthermore, the preparation conditions of the powder 2 are as follows: 2-10 parts by weight of ZrOCl2·8H2O, 0.01-1 parts by weight, preferably 0.01-0.5 parts by weight of Y(NO3)3·6H2O, dissolved in deionized water to prepare solution 1; ammonia water is taken, the amount ratio of ammonia water to ZrOCl2·8H2O is 1mL:1-5g, preferably 1mL:1-3g, 0.5-2 parts by weight, preferably 0.5-1.2 parts by weight of glycine and 0.5-5 parts by weight, preferably 0.5 -3 parts by weight of KCl, stirred evenly to prepare solution 2; placing solution 1 on a constant temperature magnetic stirrer at 60-90°C, adding solution 2 to form a mixed solution, adding deionized water to adjust the total volume of the mixed solution to a volume-to-weight ratio of the mixed solution to ZrOCl2·8H2O of 5-15 mL:1 g, preferably 6-12 mL:1 g, quickly transferring the solution to a reactor, hydrothermally reacting at 160-200°C for 20-30 hours, cooling, centrifuging and washing, and vacuum drying at 70-90°C for 2-5 hours to obtain powder 2.

[0017] The present invention also provides a method for preparing a ternary lithium battery positive electrode material using the prepared nano-composite zirconium dioxide, which comprises the following steps: mixing a lithium source and nickel-cobalt-manganese hydroxide at a molar ratio of 1-3:1-3, calcining the mixture, and crushing the mixture to obtain a material to be coated; then mixing the material to be coated, nano-composite zirconium dioxide, LiAlO2 powder, and LiF powder at a mass ratio of 15-50:50-120:1-5:0.5-2, and ball milling the mixture to obtain a composite powder; and calcining the composite powder in an air atmosphere to obtain a nano-composite zirconium dioxide-coated ternary positive electrode material.

[0018] Preferably, the molar ratio of the lithium source to the nickel-cobalt-manganese hydroxide is 1:1.1, the lithium source is lithium carbonate, and the nickel-cobalt-manganese hydroxide is Ni 0.6 Co 0.2 Mn 0.2 (OH)2 or Ni 0.8 Co 0.1 Mn 0.1 (OH)2; the mass ratio of the material to be coated, nano-composite zirconium dioxide, LiAlO2 powder, and LiF powder is 10-30:80-120:1-3:0.5-1.5.

[0019] Furthermore, the ball milling conditions are: ball milling at 100-400 rpm for 10-20 hours; the calcination conditions are: heating to 400-600° C., preferably 400-500° C., at a heating rate of 5-10° C. / min, and calcining for 3-7 hours.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: the nano-composite zirconium dioxide has good dispersibility, small particle size, average diameter between 10-50nm, and good high-temperature stability; HCl gas is introduced during the preparation process of powder 1 to prevent hydrolysis of the raw materials, and the surfactant polyvinyl pyrrolidone is added to reduce the surface tension of the solution, promote atomization to generate finer droplets, and obtain zirconium dioxide powder 1 with small particle size and good dispersibility. After mixing with zirconium dioxide powder 2, the overall dispersibility and particle size of the nano-composite zirconium dioxide are improved. LiAlO2 and LiF added in the preparation of ternary lithium battery positive electrode materials provide additional lithium ion channels, optimize the positive electrode-electrolyte interface, reduce side reactions, and improve cycle stability. Ti in powder 1 4+ and Nb 5+ Replace Zr at high temperature 4+ , generating oxygen vacancies, alleviating the impact of non-conductivity brought by LiAlO2 and LiF on the material, and improving ionic conductivity; Nb 5+ d 0 The electronic configuration enhances the n-type semiconductor properties and also improves the electronic conductivity of the positive electrode material of the ternary lithium battery.

[0021] In summary, through the effects of the above-mentioned technical means, the present invention provides a method for preparing nano-composite zirconium dioxide and a ternary lithium battery positive electrode material containing the same. The prepared nano-composite zirconium dioxide has a small overall particle size, high dispersibility and stable properties at high temperatures. The ternary lithium battery positive electrode material containing the same has the characteristics of high electrical conductivity and high discharge capacity retention rate after cyclic use. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a SEM photo of the nanocomposite zirconium dioxide prepared in Example 1.

[0023] Figure 2This is the XRD pattern of powder 2 prepared in Example 1. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to specific examples, but the present invention is not limited to the contents of the specification. All reagents used are commercially available reagents in the art.

[0025] ZrCl4 was purchased from Shanghai Yantou New Material Technology Co., Ltd.

[0026] Polyvinylpyrrolidone K12, Polyvinylpyrrolidone K30 Guangdong Yuemei Chemical Co., Ltd.;

[0027] Y(NO3)3·6H2O was purchased from Hubei Chengfeng Chemical Co., Ltd.;

[0028] Ethanol and acetone were purchased from Shandong Xiangsheng Fine Chemical Co., Ltd.;

[0029] ZrOCl2·8H2O and lithium carbonate were purchased from Shanghai Zhanyun Chemical Co., Ltd.;

[0030] KCl was purchased from Changde Beekman Biotechnology Co., Ltd.;

[0031] Glycine and were purchased from Hebei Cang Ruoshen Biotechnology Co., Ltd.;

[0032] Ni 0.6 Co 0.2 Mn 0.2 (OH)2 was purchased from Dalian Ruiyuan Power Co., Ltd.;

[0033] PVDF (polyvinylidene fluoride) was purchased from Dongguan Zhanyang Polymer Materials Co., Ltd.;

[0034] SuperP (conductive carbon black) was purchased from Tianjin Huacai Chemical Co., Ltd.;

[0035] NMP as solvent was purchased from Shandong Yousuo Chemical Technology Co., Ltd.;

[0036] Aluminum foil was purchased from Shandong Xinhe Aluminum Co., Ltd.;

[0037] Lithium metal sheets were purchased from Dongguan Liren New Material Technology Co., Ltd.

[0038] Celgard 2500 was purchased from Taorong Trading Company in Xinchang County;

[0039] Ethylene carbonate was purchased from Jinan Xinhai Chemical Technology Co., Ltd., ethyl methyl carbonate was purchased from Shandong Jingtai Chemical Co., Ltd., and vinylene carbonate was purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.

[0040] Example 1

[0041] (1) Preparation of powder 1: Weigh 20 g of ZrCl4 and dissolve it in a mixture of 86 mL of ethanol and acetone (the volume ratio of the two is 1:1), add 1 g of Ti(OEt)4 and 0.6 g of NbCl5, and stir at 40°C to completely dissolve and mix them evenly. The volume ratio of ethanol to acetone is 1:1, and stir until they are completely dissolved; slowly introduce 50 mL of HCl gas, add 2 g of polyvinylpyrrolidone K12, and stir evenly to obtain a precursor solution; at an air flow rate of 3 L / min and an oxygen pressure of 150 kPa, the hydrogen flow rate is fed at a rate of 3 mL / min, and then the precursor solution is injected into a flame spray pyrolysis device by an injection pump, pyrolyzed at 1000°C for 10 s, rapidly cooled, and the ZrO2-Nb-TiO2 nanopowder, i.e., powder 1, is collected by a filter;

[0042] Preparation of powder 2: Solution 1: Weigh 4.03 g of ZrOCl2·8H2O and 38.3 mg of Y(NO3)3·6H2O, dissolve them in 20.0 mL of deionized water, and stir evenly; Solution 2: Take 2 mL of ammonia water, add 0.94 g of glycine and 1.86 g of KCl, and stir until completely dissolved; Place solution 1 on a constant temperature magnetic stirrer at 85°C, slowly add solution 2 to form a mixed solution, add deionized water to adjust the mixed solution to 40 mL, and then quickly transfer the mixed solution to a 50 mL reactor and react at 180°C for 24 hours; After the reaction is completed, cool to room temperature, centrifuge the product, wash several times with deionized water, and finally vacuum dry at 80°C for 3 hours to obtain yttrium-doped zirconium dioxide powder, i.e., powder 2;

[0043] Repeat the preparation of the two zirconium dioxide powders to obtain sufficient product, and evenly mix 100 g of powder 1 and powder 2 in a weight ratio of 4:6 to obtain nanocomposite zirconium oxide;

[0044] (2) According to the molar ratio of lithium source to nickel-cobalt-manganese hydroxide of 1:1.1, lithium carbonate and Ni 0.6 Co 0.1 Mn 0.3 (OH)2 and mix well to obtain a mixed material, and then put the mixed material into a box furnace with an oxygen atmosphere and a gas flow rate of 3m 3 / h, firstly heat the temperature to 700℃ at a heating rate of 5℃ / min and pre-calcine for 6h, then heat the temperature to 960℃ at a heating rate of 5℃ / min and calcine for 10h, cool to room temperature with the furnace, crush and sieve to obtain a calcined product with a particle size of about 5μm, i.e., the material to be coated;

[0045] (3) 20 g of the calcined product obtained in step (2) and 100 g of the above-mentioned nano-composite zirconium dioxide powder obtained in step (1) were added with 3 g of LiAlO2 powder and 1 g of LiF powder, and the mixture was ball-milled at 300 r for 15 h to obtain a composite powder; then the composite powder was placed in a box furnace, heated to 500 ° C at a heating rate of 5 ° C / min in an air atmosphere, and calcined for 4 h. The mixture was naturally cooled and sieved to obtain a nano-composite zirconium dioxide powder-coated ternary positive electrode material.

[0046] The SEM image of the nanocomposite zirconium oxide obtained in step (1) is shown in Figure 1; the XRD pattern of the powder 2 obtained in step (1) is shown in Figure 2. Figure 2 shown.

[0047] Example 2

[0048] Polyvinylpyrrolidone K12 was replaced by polyvinylpyrrolidone K30, and other conditions were the same as those in Example 1. The specific operations were as follows:

[0049] (1) Preparation of powder 1: Weigh 20g of ZrCl4 solid and dissolve it in a mixture of 86mL of ethanol and acetone (the volume ratio of the two is 1:1), add 1g of Ti(OEt)4 and 0.6g of NbCl5, stir at 40℃ to completely dissolve and mix evenly, the volume ratio of ethanol and acetone is 1:1, and stir until completely dissolved. Slowly introduce 50mL of HCl gas, add 2g of polyvinylpyrrolidone K30, and stir evenly to obtain a precursor solution. At an air flow rate of 3L / min and an oxygen pressure of 150KPa, the hydrogen flow rate is fed at a rate of 3mL / min, and then the precursor solution is injected into a flame spray pyrolysis device by an injection pump, pyrolyzed at 1000℃ for 10s, quickly cooled, and the ZrO2-Nb-TiO2 nanopowder, i.e. powder 1, is collected by a filter;

[0050] Preparation of Powder 2: Solution 1: Weigh 4.03 g of ZrOCl2·8H2O and 38.3 mg of Y(NO3)3·6H2O, dissolve in 20.0 mL of deionized water, and stir evenly; Solution 2: Take 2 mL of ammonia water, add 0.94 g of glycine and 1.86 g of KCl, and stir until completely dissolved. Place Solution 1 on a constant temperature magnetic stirrer at 85°C, slowly add Solution 2 to form a mixed solution, add deionized water to adjust the mixed solution to 40 mL, and then quickly transfer the mixed solution to a 50 mL reactor and react at 180°C for 24 hours; after the reaction is completed, cool to room temperature, centrifuge the product, wash several times with deionized water, and finally vacuum dry at 80°C for 3 hours to obtain yttrium-doped zirconium dioxide powder, i.e., zirconium dioxide, i.e., powder 2;

[0051] The preparation of the two zirconium dioxide powders was repeated to obtain a sufficient amount of product. A total of 100 g of powder 1 and powder 2 were mixed in a weight ratio of 4:6 to obtain nano-composite zirconium dioxide.

[0052] (2) According to the molar ratio of lithium source to nickel-cobalt-manganese hydroxide of 1:1.1, lithium carbonate and Ni 0.6 Co 0.1 Mn 0.3 (OH)2 and mix well to obtain a mixed material, and then put the mixed material into a box furnace with an oxygen atmosphere and a gas flow rate of 3m 3 / h, firstly heat the temperature to 700℃ at a heating rate of 5℃ / min and pre-calcine for 6h, then heat the temperature to 960℃ at a heating rate of 5℃ / min and calcine for 10h, cool to room temperature with the furnace, crush and sieve to obtain a calcined product with a particle size of about 5μm, i.e., the material to be coated;

[0053] (3) 20 g of the calcined product obtained in step (2) and 100 g of the above-mentioned nano-composite zirconium dioxide powder obtained in step (1) were added with 3 g of LiAlO2 powder and 1 g of LiF powder, and the mixture was ball-milled at 300 r for 15 h to obtain a composite powder; then the composite powder was placed in a box furnace, heated to 500 ° C at a heating rate of 5 ° C / min in an air atmosphere, and calcined for 4 h. The mixture was naturally cooled and sieved to obtain a nano-composite zirconium dioxide powder-coated ternary positive electrode material.

[0054] Example 3

[0055] The amount of polyvinyl pyrrolidone K12 added was doubled, and other conditions were the same as in Example 1. The specific operations were as follows:

[0056] (1) Preparation of powder 1: Weigh 20g of ZrCl4 solid and dissolve it in a mixture of 86mL of ethanol and acetone (the volume ratio of the two is 1:1), add 1g of Ti(OEt)4 and 0.6g of NbCl5, stir at 40℃ to completely dissolve and mix evenly, the volume ratio of ethanol and acetone is 1:1, and stir until completely dissolved. Slowly introduce 50mL of HCl gas, add 4g of polyvinylpyrrolidone K12, and stir evenly to obtain a precursor solution. At an air flow rate of 3L / min and an oxygen pressure of 150KPa, the hydrogen flow rate is fed at a rate of 3mL / min, and then the precursor solution is injected into a flame spray pyrolysis device by an injection pump, pyrolyzed at 1000℃ for 10s, quickly cooled, and the ZrO2-Nb-TiO2 nanopowder, i.e. powder 1, is collected by a filter;

[0057] Preparation of Powder 2: Solution 1: Weigh 4.03 g of ZrOCl2·8H2O and 38.3 mg of Y(NO3)3·6H2O, dissolve in 20.0 mL of deionized water, and stir evenly; Solution 2: Take 2 mL of ammonia water, add 0.94 g of glycine and 1.86 g of KCl, and stir until completely dissolved. Place Solution 1 on a constant temperature magnetic stirrer at 85°C, slowly add Solution 2 to form a mixed solution, add deionized water to adjust the mixed solution to 40 mL, and then quickly transfer the mixed solution to a 50 mL reactor and react at 180°C for 24 hours; after the reaction is completed, cool to room temperature, centrifuge the product, wash it several times with deionized water, and finally vacuum dry it at 80°C for 3 hours to obtain yttrium-doped zirconium dioxide powder, i.e., powder 2.

[0058] Repeat the preparation of the two zirconium dioxide powders to obtain sufficient product, and evenly mix 100 g of powder 1 and powder 2 in a weight ratio of 4:6 to obtain nanocomposite zirconium dioxide;

[0059] (2) According to the molar ratio of lithium source to nickel-cobalt-manganese hydroxide precursor of 1:1.1, lithium carbonate and Ni 0.6 Co 0.1 Mn 0.3 (OH)2 and mix well to obtain a mixed material, and then put the mixed material into a box furnace with an oxygen atmosphere and a gas flow rate of 3m 3 / h, firstly heat the temperature to 700℃ at a heating rate of 5℃ / min and pre-calcine for 6h, then heat the temperature to 960℃ at a heating rate of 5℃ / min and calcine for 10h, cool to room temperature with the furnace, crush and sieve to obtain a calcined product with a particle size of about 5μm, i.e., the material to be coated;

[0060] (3) 20 g of the calcined product obtained in step (2) and 100 g of the above-mentioned nano-composite zirconium dioxide powder obtained in step (1) were added with 3 g of LiAlO2 powder and 1 g of LiF powder, and the mixture was ball-milled at 300 r for 15 h to obtain a composite powder; the composite powder was then placed in a box furnace, heated to 500 ° C at a heating rate of 5 ° C / min in an air atmosphere, and calcined for 4 h. The mixture was naturally cooled and sieved to obtain a nano-composite zirconium dioxide powder-coated ternary positive electrode material.

[0061] Example 4

[0062] Increase the amount of Ti(OEt)4 added to 1.5g, increase the amount of NbCl5 added to 0.8g, and other conditions are the same as in Example 1. The specific operation is as follows

[0063] (1) Preparation of powder 1: Weigh 20g of ZrCl4 solid and dissolve it in a mixture of 86mL of ethanol and acetone (the volume ratio of the two is 1:1), add 1.5g of Ti(OEt)4 and 0.8g of NbCl5, stir at 40℃ to completely dissolve and mix evenly, the volume ratio of ethanol and acetone is 1:1, and stir until completely dissolved. Slowly introduce 50mL of HCl gas, add 2g of polyvinylpyrrolidone K12, and stir evenly to obtain a precursor solution. At an air flow rate of 3L / min and an oxygen pressure of 150KPa, the hydrogen flow rate is fed at a rate of 3mL / min, and then the precursor solution is injected into a flame spray pyrolysis device by an injection pump, pyrolyzed at 1000℃ for 10s, quickly cooled, and the ZrO2-Nb-TiO2 nanopowder, i.e. powder 1, is collected by a filter;

[0064] Preparation of Powder 2: Solution 1: Weigh 4.03 g of ZrOCl2·8H2O and 38.3 mg of Y(NO3)3·6H2O, dissolve in 20.0 mL of deionized water, and stir evenly; Solution 2: Take 2 mL of ammonia water, add 0.94 g of glycine and 1.86 g of KCl, and stir until completely dissolved. Place Solution 1 on a constant temperature magnetic stirrer at 85°C, slowly add Solution 2 to form a mixed solution, add deionized water to adjust the mixed solution to 40 mL, and then quickly transfer the mixed solution to a 50 mL reactor and react at 180°C for 24 hours; after the reaction is completed, cool to room temperature, centrifuge the product, wash it several times with deionized water, and finally vacuum dry it at 80°C for 3 hours to obtain yttrium-doped zirconium dioxide powder, i.e., powder 2.

[0065] Repeat the preparation of the two zirconium dioxide powders to obtain sufficient product, and mix 100 g of powder 1 and powder 2 in a weight ratio of 4:6 to obtain nano-composite zirconium dioxide;

[0066] (2) According to the molar ratio of lithium source to nickel-cobalt-manganese hydroxide precursor of 1:1.1, lithium carbonate and Ni 0.6 Co 0.1 Mn 0.3 (OH)2 and mix well to obtain a mixed material, and then put the mixed material into a box furnace with an oxygen atmosphere and a gas flow rate of 3m 3 / h, firstly heat the temperature to 700℃ at a heating rate of 5℃ / min and pre-calcine for 6h, then heat the temperature to 960℃ at a heating rate of 5℃ / min and calcine for 10h, cool to room temperature with the furnace, crush and sieve to obtain a calcined product with a particle size of about 5μm, i.e., the material to be coated;

[0067] (3) 20 g of the calcined product obtained in step (2) and 100 g of the above-mentioned nano-composite zirconium dioxide powder obtained in step (1) were added with 3 g of LiAlO2 powder and 2 g of LiF powder, and the mixture was ball-milled at 300 r for 15 h to obtain a composite powder; then the composite powder was placed in a box furnace, heated to 500 ° C at a heating rate of 5 ° C / min in an air atmosphere, and calcined for 4 h. The mixture was naturally cooled and sieved to obtain a nano-composite zirconium dioxide powder-coated ternary positive electrode material.

[0068] Example 5

[0069] The mixing ratio of the two powders was changed. Powder 1 and powder 2 totaling 100 g were mixed in a weight ratio of 3:7. Other conditions were the same as those in Example 1. The specific operations were as follows:

[0070] (1) Preparation of powder 1: Weigh 20g of ZrCl4 solid and dissolve it in a mixture of 86mL of ethanol and acetone (the volume ratio of the two is 1:1), add 1.5g of Ti(OEt)4 and 0.6g of NbCl5, stir at 40℃ to completely dissolve and mix evenly, the volume ratio of ethanol and acetone is 1:1, and stir until completely dissolved. Slowly introduce 50mL of HCl gas, add 2g of polyvinylpyrrolidone K12, and stir evenly to obtain a precursor solution. At an air flow rate of 3L / min and an oxygen pressure of 150KPa, the hydrogen flow rate is fed at a rate of 3mL / min, and then the precursor solution is injected into a flame spray pyrolysis device by an injection pump, pyrolyzed at 1000℃ for 10s, quickly cooled, and the ZrO2-Nb-TiO2 nanopowder, i.e. powder 1, is collected by a filter;

[0071] Preparation of Powder 2: Solution 1: Weigh 4.03 g of ZrOCl2·8H2O and 38.3 mg of Y(NO3)3·6H2O, dissolve in 20.0 mL of deionized water, and stir evenly; Solution 2: Take 2 mL of ammonia water, add 0.94 g of glycine and 1.86 g of KCl, and stir until completely dissolved. Place Solution 1 on a constant temperature magnetic stirrer at 85°C, slowly add Solution 2 to form a mixed solution, add deionized water to adjust the mixed solution to 40 mL, and then quickly transfer the mixed solution to a 50 mL reactor and react at 180°C for 24 hours; after the reaction is completed, cool to room temperature, centrifuge the product, wash it several times with deionized water, and finally vacuum dry it at 80°C for 3 hours to obtain yttrium-doped zirconium dioxide powder, i.e., powder 2.

[0072] Repeat the preparation of the two zirconium dioxide powders to obtain sufficient product, and evenly mix 100 g of powder 1 and powder 2 in a weight ratio of 3:7 to obtain nanocomposite zirconium dioxide;

[0073] (2) According to the molar ratio of lithium source to nickel-cobalt-manganese hydroxide precursor of 1:1.1, lithium carbonate and Ni0.6 Co 0.1 Mn 0.3 (OH)2 and mix well to obtain a mixed material, and then put the mixed material into a box furnace with an oxygen atmosphere and a gas flow rate of 3m 3 / h, firstly heat the temperature to 700℃ at a heating rate of 5℃ / min and pre-calcine for 6h, then heat the temperature to 960℃ at a heating rate of 5℃ / min and calcine for 10h, cool to room temperature with the furnace, crush and sieve to obtain a calcined product with a particle size of about 5μm, i.e., the material to be coated;

[0074] (3) 20 g of the calcined product obtained in step (2) and 100 g of the above-mentioned nano-composite zirconium dioxide powder obtained in step (1) were added with 3 g of LiAlO2 powder and 2 g of LiF powder, and the mixture was ball-milled at 300 r for 15 h to obtain a composite powder; then the composite powder was placed in a box furnace, heated to 500 ° C at a heating rate of 5 ° C / min in an air atmosphere, and calcined for 4 h. The mixture was naturally cooled and sieved to obtain a nano-composite zirconium dioxide powder-coated ternary positive electrode material.

[0075] Example 6

[0076] The amount of LiAlO2 powder added was increased to 5 g. Other conditions were the same as in Example 1. The specific operations were as follows:

[0077] (1) Preparation of powder 1: Weigh 20g of ZrCl4 solid and dissolve it in 86mL of a mixed solution of ethanol and acetone (the volume ratio of the two is 1:1), add 1g of Ti(OEt)4 and 0.6g of NbCl5, stir at 40℃ to completely dissolve and mix evenly, the volume ratio of ethanol and acetone is 1:1, and stir until completely dissolved. Slowly introduce 50mL of HCl gas, add 2g of polyvinylpyrrolidone K12, and stir evenly to obtain a precursor solution. At an air flow rate of 3L / min and an oxygen pressure of 150KPa, the hydrogen flow rate is fed at a rate of 3mL / min, and then the precursor solution is injected into a flame spray pyrolysis device by an injection pump, pyrolyzed at 1000℃ for 10s, quickly cooled, and the ZrO2-Nb-TiO2 nanopowder, i.e. powder 1, is collected by a filter;

[0078] Preparation of Powder 2: Solution 1: Weigh 4.03 g of ZrOCl2·8H2O and 38.3 mg of Y(NO3)3·6H2O, dissolve in 20.0 mL of deionized water, and stir evenly; Solution 2: Take 2 mL of ammonia water, add 0.94 g of glycine and 1.86 g of KCl, and stir until completely dissolved. Place Solution 1 on a constant temperature magnetic stirrer at 85°C, slowly add Solution 2 to form a mixed solution, add deionized water to adjust the mixed solution to 40 mL, and then quickly transfer the mixed solution to a 50 mL reactor and react at 180°C for 24 hours; after the reaction is completed, cool to room temperature, centrifuge the product, wash it several times with deionized water, and finally vacuum dry it at 80°C for 3 hours to obtain yttrium-doped zirconium dioxide powder, i.e., powder 2.

[0079] Repeat the preparation of the two zirconium dioxide powders to obtain sufficient product, and evenly mix 100 g of powder 1 and powder 2 in a weight ratio of 4:6 to obtain nanocomposite zirconium dioxide;

[0080] (2) According to the molar ratio of lithium source to nickel-cobalt-manganese hydroxide precursor of 1:1.1, lithium carbonate and Ni 0.6 Co 0.1 Mn 0.3 (OH)2 and mix well to obtain a mixed material, and then put the mixed material into a box furnace with an oxygen atmosphere and a gas flow rate of 3m 3 / h, first heat the temperature to 700℃ at a heating rate of 5℃ / min and pre-calcine for 6h, then heat the temperature to 960℃ at a heating rate of 5℃ / min and calcine for 10h, cool to room temperature with the furnace, crush and sieve to obtain a calcined product with a particle size of about 5μm, that is, the material to be coated; (3) 20g of the calcined product prepared in step (2) and 100g of the above-mentioned nano-composite zirconium dioxide powder prepared in step (1) are added with 5g of LiAlO2 powder and 1g of LiF powder, and ball milled at 300r for 15h to obtain a composite powder; the composite powder is placed in a box furnace, heated to 500℃ at a heating rate of 5℃ / min in an air atmosphere and calcined for 4h, naturally cooled and sieved to obtain a nano-composite zirconium dioxide powder coated ternary positive electrode material.

[0081] Example 7

[0082] The amount of LiF powder added was increased to 2 g. Other conditions were the same as in Example 1. The specific operations were as follows:

[0083] (1) Preparation of powder 1: Weigh 20g of ZrCl4 solid and dissolve it in a mixture of 86mL of ethanol and acetone (the volume ratio of the two is 1:1), add 1g of Ti(OEt)4 and 0.6g of NbCl5, stir at 40℃ to completely dissolve and mix evenly, the volume ratio of ethanol and acetone is 1:1, and stir until completely dissolved. Slowly introduce 50mL of HCl gas, add 2g of polyvinylpyrrolidone K12, and stir evenly to obtain a precursor solution. At an air flow rate of 3L / min and an oxygen pressure of 150KPa, the hydrogen flow rate is fed at a rate of 3mL / min, and then the precursor solution is injected into a flame spray pyrolysis device by an injection pump, pyrolyzed at 1000℃ for 10s, quickly cooled, and the ZrO2-Nb-TiO2 nanopowder, i.e. powder 1, is collected by a filter;

[0084] Preparation of Powder 2: Solution 1: Weigh 4.03 g of ZrOCl2·8H2O and 38.3 mg of Y(NO3)3·6H2O, dissolve in 20.0 mL of deionized water, and stir evenly; Solution 2: Take 2 mL of ammonia water, add 0.94 g of glycine and 1.86 g of KCl, and stir until completely dissolved. Place Solution 1 on a constant temperature magnetic stirrer at 85°C, slowly add Solution 2 to form a mixed solution, add deionized water to adjust the mixed solution to 40 mL, and then quickly transfer the mixed solution to a 50 mL reactor and react at 180°C for 24 hours; after the reaction is completed, cool to room temperature, centrifuge the product, wash it several times with deionized water, and finally vacuum dry it at 80°C for 3 hours to obtain yttrium-doped zirconium dioxide powder, i.e., powder 2.

[0085] Repeat the preparation of the two zirconium dioxide powders to obtain sufficient product, and evenly mix 100 g of powder 1 and powder 2 in a weight ratio of 4:6 to obtain nano-composite zirconium dioxide;

[0086] (2) According to the molar ratio of lithium source to nickel-cobalt-manganese hydroxide precursor of 1:1.1, lithium carbonate and Ni 0.6 Co 0.1 Mn 0.3 (OH)2 and mix well to obtain a mixed material, and then put the mixed material into a box furnace with an oxygen atmosphere and a gas flow rate of 3m 3 / h, first heat the temperature to 700℃ at a heating rate of 5℃ / min and pre-calcine for 6h, then heat the temperature to 960℃ at a heating rate of 5℃ / min and calcine for 10h, cool to room temperature with the furnace, crush and sieve to obtain a calcined product with a particle size of about 5μm, that is, the material to be coated; (3) 20g of the calcined product prepared in step (2) and 100g of the above-mentioned nano-composite zirconium dioxide powder prepared in step (1) are added with 3g of LiAlO2 powder and 2g of LiF powder, and ball milled at 300r for 15h to mix evenly to obtain a composite powder; the composite powder is placed in a box furnace, heated to 500℃ at a heating rate of 5℃ / min in an air atmosphere and calcined for 4h, naturally cooled and sieved to obtain a nano-composite zirconium dioxide powder coated ternary positive electrode material.

[0087] Comparative Example 1

[0088] No HCl gas was introduced, no polyvinyl pyrrolidone was added, and other conditions were the same as in Example 1. The specific operation was as follows:

[0089] (1) Preparation of Powder 1: Weigh 20 g of ZrCl4 solid and dissolve it in a mixture of 86 mL of ethanol and acetone (the volume ratio of the two is 1:1). Add 1.5 g of Ti(OEt)4 and 0.6 g of NbCl5, stir at 40°C to completely dissolve and mix evenly. The volume ratio of ethanol to acetone is 1:1. Stir until completely dissolved to obtain a precursor solution. At an air flow rate of 3 L / min and an oxygen pressure of 150 kPa, the hydrogen flow rate is fed at a rate of 3 mL / min. Then, the precursor solution is injected into a flame spray pyrolysis device through a syringe pump, pyrolyzed at 1000°C for 10 seconds, rapidly cooled, and the ZrO2-Nb-TiO2 nanopowder, i.e., powder 1, is collected by a filter.

[0090] Preparation of Powder 2: Solution 1: Weigh 4.03 g of ZrOCl2·8H2O and 38.3 mg of Y(NO3)3·6H2O, dissolve in 20.0 mL of deionized water, and stir evenly; Solution 2: Take 2 mL of ammonia water, add 0.94 g of glycine and 1.86 g of KCl, and stir until completely dissolved. Place Solution 1 on a constant temperature magnetic stirrer at 85°C, slowly add Solution 2 to form a mixed solution, add deionized water to adjust the mixed solution to 40 mL, and then quickly transfer the mixed solution to a 50 mL reactor and react at 180°C for 24 hours; after the reaction is completed, cool to room temperature, centrifuge the product, wash it several times with deionized water, and finally vacuum dry it at 80°C for 3 hours to obtain yttrium-doped zirconium dioxide powder, i.e., powder 2.

[0091] Repeat the preparation of the two zirconium dioxide powders to obtain sufficient product, and evenly mix 100 g of powder 1 and powder 2 in a weight ratio of 4:6 to obtain nanocomposite zirconium dioxide;

[0092] (2) According to the molar ratio of lithium in the lithium source to nickel, cobalt and manganese in the nickel, cobalt and manganese hydroxide precursor of 1:1.1, lithium carbonate and Ni 0.6 Co 0.1 Mn 0.3 (OH)2 and mix well to obtain a mixed material, and then put the mixed material into a box furnace with an oxygen atmosphere and a gas flow rate of 3m 3 / h, firstly heat the temperature to 700℃ at a heating rate of 5℃ / min and pre-calcine for 6h, then heat the temperature to 960℃ at a heating rate of 5℃ / min and calcine for 10h, cool to room temperature with the furnace, crush and sieve to obtain a calcined product with a particle size of about 5μm, i.e., the material to be coated;

[0093] (3) 20 g of the calcined product obtained in step (2) and 100 g of the above-mentioned nano-composite zirconium dioxide powder obtained in step (1) were added with 3 g of LiAlO2 powder and 2 g of LiF powder, and the mixture was ball-milled at 300 r for 15 h to obtain a composite powder; the composite powder was placed in a box furnace, heated to 500 ° C at a heating rate of 5 ° C / min in an air atmosphere, and calcined for 4 h, and naturally cooled and sieved to obtain a nano-composite zirconium dioxide powder-coated ternary positive electrode material.

[0094] Comparative Example 2

[0095] In step (3), LiAlO2 powder and LiF powder are not added, and other conditions are the same as those in Example 1. The specific operation is as follows:

[0096] (1) Preparation of powder 1: Weigh 20g of ZrCl4 solid and dissolve it in a mixture of 86mL of ethanol and acetone (the volume ratio of the two is 1:1), add 1.5g of Ti(OEt)4 and 0.6g of NbCl5, stir at 40℃ to completely dissolve and mix evenly, the volume ratio of ethanol and acetone is 1:1, and stir until completely dissolved. Slowly introduce 50mL of HCl gas, add 2g of polyvinylpyrrolidone K12, and stir evenly to obtain a precursor solution. At an air flow rate of 3L / min and an oxygen pressure of 150KPa, the hydrogen flow rate is fed at a rate of 3mL / min, and then the precursor solution is injected into a flame spray pyrolysis device by an injection pump, pyrolyzed at 1000℃ for 10s, quickly cooled, and the ZrO2-Nb-TiO2 nanopowder, i.e. powder 1, is collected by a filter;

[0097] Preparation of Powder 2: Solution 1: Weigh 4.03 g of ZrOCl2·8H2O and 38.3 mg of Y(NO3)3·6H2O, dissolve in 20.0 mL of deionized water, and stir evenly; Solution 2: Take 2 mL of ammonia water, add 0.94 g of glycine and 1.86 g of KCl, and stir until completely dissolved. Place Solution 1 on a constant temperature magnetic stirrer at 85°C, slowly add Solution 2 to form a mixed solution, add deionized water to adjust the mixed solution to 40 mL, and then quickly transfer the mixed solution to a 50 mL reactor and react at 180°C for 24 hours; after the reaction is completed, cool to room temperature, centrifuge the product, wash it several times with deionized water, and finally vacuum dry it at 80°C for 3 hours to obtain yttrium-doped zirconium dioxide powder, i.e., powder 2.

[0098] Repeat the preparation of the two zirconium dioxide powders to obtain sufficient product, and evenly mix 100 g of powder 1 and powder 2 in a weight ratio of 4:6 to obtain nanocomposite zirconium dioxide;

[0099] (2) According to the molar ratio of lithium in the lithium source to nickel, cobalt and manganese in the nickel, cobalt and manganese hydroxide precursor of 1:1.1, lithium carbonate and Ni 0.6 Co 0.1 Mn 0.3 (OH)2 and mix well to obtain a mixed material, and then put the mixed material into a box furnace with an oxygen atmosphere and a gas flow rate of 3m 3 / h, first heat it to 700℃ at a heating rate of 5℃ / min and pre-calcine for 6h, then heat it to 960℃ at a heating rate of 5℃ / min and calcine for 10h, cool it to room temperature with the furnace, crush it and sieve it to obtain a calcined product with a particle size of about 5μm, that is, the material to be coated; (3) 20g of the calcined product obtained in step (2) and 100g of the above-mentioned nano-composite zirconium dioxide powder obtained in step (1) are ball-milled at 300r for 15h to obtain a composite powder; the composite powder is placed in a box furnace, heated to 500℃ at a heating rate of 5℃ / min in an air atmosphere and calcined for 4h, naturally cooled and sieved to obtain a nano-composite zirconium dioxide powder coated ternary positive electrode material.

[0100] Comparative Example 3

[0101] In step (1), Ti(OEt)4 and NbCl5 are not added, and other conditions are the same as those in Example 1. The specific operation is as follows:

[0102] (1) Preparation of powder 1: Weigh 20 g of ZrCl4 solid and dissolve it in a mixture of 86 mL of ethanol and acetone (the volume ratio of the two is 1:1), stir it at 40 ° C to completely dissolve and mix it evenly, the volume ratio of ethanol and acetone is 1:1, and stir until it is completely dissolved. Slowly introduce 50 mL of HCl gas, add 2 g of polyvinylpyrrolidone K12, and stir evenly to obtain a precursor solution. At an air flow rate of 3 L / min and an oxygen pressure of 150 kPa, the hydrogen flow rate is fed at a rate of 3 mL / min, and then the precursor solution is injected into a flame spray pyrolysis device by an injection pump, pyrolyzed at 1000 ° C for 10 seconds, quickly cooled, and collected through a filter to obtain powder 1;

[0103] Preparation of Powder 2: Solution 1: Weigh 4.03 g of ZrOCl2·8H2O and 38.3 mg of Y(NO3)3·6H2O, dissolve in 20.0 mL of deionized water, and stir evenly; Solution 2: Take 2 mL of ammonia water, add 0.94 g of glycine and 1.86 g of KCl, and stir until completely dissolved. Place Solution 1 on a constant temperature magnetic stirrer at 85°C, slowly add Solution 2 to form a mixed solution, add deionized water to adjust the mixed solution to 40 mL, and then quickly transfer the mixed solution to a 50 mL reactor and react at 180°C for 24 hours; after the reaction is completed, cool to room temperature, centrifuge the product, wash it several times with deionized water, and finally vacuum dry it at 80°C for 3 hours to obtain yttrium-doped zirconium dioxide powder, i.e., powder 2.

[0104] Repeat the preparation of the two zirconium dioxide powders to obtain sufficient product, and evenly mix 100 g of powder 1 and powder 2 in a weight ratio of 4:6 to obtain nanocomposite zirconium dioxide;

[0105] (2) According to the molar ratio of lithium in the lithium source to nickel, cobalt and manganese in the nickel, cobalt and manganese hydroxide precursor of 1:1.1, lithium carbonate and Ni 0.6 Co 0.1 Mn 0.3 (OH)2 and mix well to obtain a mixed material, and then put the mixed material into a box furnace with an oxygen atmosphere and a gas flow rate of 3m 3 / h, firstly heat the temperature to 700℃ at a heating rate of 5℃ / min and pre-calcine for 6h, then heat the temperature to 960℃ at a heating rate of 5℃ / min and calcine for 10h, cool to room temperature with the furnace, crush and sieve to obtain a calcined product with a particle size of about 5μm, i.e., the material to be coated;

[0106] (3) 20 g of the calcined product obtained in step (2) and 100 g of the above-mentioned nano-composite zirconium dioxide powder obtained in step (1) were added with 3 g of LiAlO2 powder and 2 g of LiF powder, and the mixture was ball-milled at 300 r for 15 h to obtain a composite powder; the composite powder was placed in a box furnace, heated to 500 ° C at a heating rate of 5 ° C / min in an air atmosphere, and calcined for 4 h, and naturally cooled and sieved to obtain a nano-composite zirconium dioxide powder-coated ternary positive electrode material.

[0107] The performance tests were conducted on the nanocomposite zirconium dioxide powder and the coated ternary positive electrode materials prepared in the above examples and comparative examples. The results are shown in Table 1 below.

[0108] Conductivity test of nanocomposite zirconium dioxide powder coated ternary cathode material: Using the resistivity tester Suzhou Jingge Electronics ST-2255A, take 5g of nanocomposite zirconium dioxide powder coated ternary cathode material, use an electronic press to press to 5000kg±2kg, maintain for 25s, place the sample between the tester electrodes, sample height h (cm), voltage U at both ends, current I, resistance R (KΩ), the area of the powder after pressing is S = 3.14cm 2 , the electronic conductivity of the powder is calculated according to the formula δ=h / (S*R) / 1000, the unit is S·cm -1 .

[0109] The discharge capacity and cycling performance testing methods are as follows: A ternary cathode material coated with nanocomposite zirconium dioxide powder, PVDF (polyvinylidene fluoride), and SuperP (conductive carbon black) were mixed in a mass ratio of 8:1:1. NMP was then added as a solvent to form a slurry, which was then coated onto aluminum foil and dried in a vacuum oven at 120°C for 12 hours. After drying, the slurry was cut into positive electrode sheets for later use. CR2016 button-type cells were assembled in a glove box using a lithium metal sheet as the negative electrode, Celgard 2500 as the separator, and a mixed solution of 1.2 mol / L ethylene carbonate (EC), ethyl methyl carbonate (EMC), and 2% vinylene carbonate (EC:EMC ratio, 3:7, by volume) as the electrolyte. After standing overnight, the discharge capacity and discharge capacity retention of the coated cathode material, i.e., the material's cycling discharge capacity performance, were tested. The LAND battery test system was used to conduct discharge capacity and charge-discharge efficiency performance tests at 25°C and 3.8V. The reference capacity was set to 200mA / g, and 1C corresponded to a current density of 200mA / g.

[0110] Table 1 Performance test of ternary lithium battery positive electrode materials containing nanocomposite zirconium dioxide

[0111]

[0112]

[0113] As can be seen from the data in Table 1, the ternary lithium battery cathode material prepared by the preparation method of the present invention has excellent performance. By optimizing the combination of the two powders, as well as various chemical doping and dispersion treatment steps, the various performance indicators of the ternary lithium battery cathode material have been improved, with high conductivity and long-cycle performance. In addition, it should be noted that the doping chemical has a significant impact on the formation and stability of the crystalline phase. Excessive doping will lead to a decrease in the stability of the physical and chemical properties of the material. Therefore, it is necessary to control the amount of doping chemical used and not to make it too high.

[0114] The above detailed description is a specific description of one feasible embodiment of the present invention. This embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or modification that does not depart from the present invention should be included in the scope of the technical solution of the present invention.

Claims

1. A nanocomposite zirconium dioxide, characterized in that: The invention comprises powder 1 and powder 2, wherein powder 1 is zirconium dioxide powder doped with Nb and Ti, and powder 2 is zirconium dioxide powder doped with yttrium.

2. The nanocomposite zirconium dioxide according to claim 1, characterized in that The mass ratio of the powder 1 to the powder 2 is 10:1-1:10, preferably 4:6-3:

7.

3. The nanocomposite zirconium dioxide according to claim 1, characterized in that The powder 1 is prepared by a pyrolysis method, and the powder 2 is prepared by a hydrothermal method.

4. A method for preparing the nanocomposite zirconium dioxide according to claim 1 or 3, characterized in that: The preparation conditions of the powder 1 are as follows: ZrCl4 is dissolved in a mixture of ethanol and acetone, Ti(OEt)4 and NbCl5 are added and stirred to dissolve; HCl gas is introduced, polyvinyl pyrrolidone is added, and the mixture is stirred to obtain a precursor solution; the precursor solution is then injected into a spray pyrolysis device, pyrolyzed at 1000-1500°C for 10-15s, preferably at 1000-1200°C for 10-12s, cooled, and filtered to obtain the powder 1; The preparation conditions of the powder 2 are as follows: ZrOCl2·8H2O and Y(NO3)3·6H2O are dissolved in deionized water to prepare solution 1; glycine / KCl is added to the ammonia water and stirred uniformly to prepare solution 2; solution 2 is added to solution 1 while stirring to form a mixed solution, the mixed solution is subjected to a hydrothermal reaction at 160-200°C, and after the reaction, the mixture is centrifuged, washed, and vacuum-dried to obtain powder 2.

5. The preparation method according to claim 4, wherein the K value of the polyvinyl pyrrolidone in the preparation of powder 1 ranges from K12 to K30.

6. The preparation method according to claim 4, wherein the preparation conditions of the powder 1 are as follows: 20-40 parts by weight, preferably 20-30 parts by weight, of ZrCl4 are dissolved in a mixture of ethanol and acetone in a volume ratio of 1:1-3, the amount ratio of ZrCl4 to the mixture of ethanol and acetone is 20-40g:70-120mL, 1-5 parts by weight, preferably 1-3 parts by weight of Ti(OEt)4 and 0.1-3 parts by weight, preferably 0.1-1 parts by weight of NbCl5 are added, and the mixture is stirred and dissolved at 40-60°C; and the mixture is slowly introduced into the mixture. 1-10 parts by weight, preferably 2-5 parts by weight, of polyvinyl pyrrolidone are added to 20-70 mL of HCl gas, and the mixture is stirred uniformly to obtain a precursor solution. Then, at an air flow rate of 3-7 L / min and an oxygen pressure of 150-200 kPa, a hydrogen flow rate feed rate of 3-7 mL / min, the precursor solution is injected into a flame spray pyrolysis device via a syringe pump, and pyrolyzed at 1000-1500° C. for 10-15 seconds, preferably at 1000-1200° C. for 10-12 seconds. The mixture is rapidly cooled and filtered to obtain powder 1.

7. The preparation method according to claim 4, wherein the preparation conditions of powder 2 are as follows: 2-10 parts by weight of ZrOCl2·8H2O and 0.01-1 parts by weight, preferably 0.01-0.5 parts by weight of Y(NO3)3·6H2O are dissolved in deionized water to prepare solution 1; ammonia water is taken, and the ratio of ammonia water to ZrOCl2·8H2O is 1 mL:1-5 g, preferably 1 mL:1-3 g, and 0.5-2 parts by weight, preferably 0.5-1.2 parts by weight of glycine and 0.5-5 parts by weight, preferably 0. 0.5-3 parts by weight of KCl are stirred evenly to prepare solution 2; solution 1 is placed on a constant temperature magnetic stirrer at 60-90°C, solution 2 is added to form a mixed solution, and the total volume of the mixed solution is adjusted by adding deionized water so that the volume-to-weight ratio of the mixed solution to ZrOCl2·8H2O is 5-15 mL:1 g, preferably 6-12 mL:1 g, and the mixed solution is quickly transferred to a reactor, hydrothermally reacted at 160-200°C for 20-30 hours, cooled, centrifuged and washed, and vacuum dried at 70-90°C for 2-5 hours to obtain powder 2.

8. A method for preparing a positive electrode material for a ternary lithium battery using the nanocomposite zirconium dioxide prepared by the preparation method according to any one of claims 4 to 7, wherein: The steps are: mixing the lithium source and nickel-cobalt-manganese hydroxide in a molar ratio of 1-3:1-3, calcining the mixture, and crushing the mixture to obtain a material to be coated; The material to be coated, nano-composite zirconium dioxide, LiAlO2 powder and LiF powder are mixed in a mass ratio of 15-50:50-120:1-5:0.5-2 and then ball-milled to obtain a composite powder; the composite powder is calcined in an air atmosphere to obtain a nano-composite zirconium dioxide coated ternary positive electrode material.

9. The method according to claim 8, characterized in that The molar ratio of the lithium source to the nickel-cobalt-manganese hydroxide is 1:1.1, the lithium source is lithium carbonate, and the nickel-cobalt-manganese hydroxide is Ni 0.6 Co 0.2 Mn 0.2 (OH)2 or Ni 0.8 Co 0.1 Mn 0.1 (OH)2; the mass ratio of the material to be coated, nano-composite zirconium dioxide powder, LiAlO2 powder, and LiF powder is 10-30:80-120:1-3:0.5-1.

5.

10. The method according to claim 8, characterized in that The ball milling conditions are: 100-400 rpm ball milling for 10-20 hours; the calcination conditions are: heating to 400-600° C., preferably 400-500° C., at a heating rate of 5-10° C. / min, and calcining for 3-7 hours.

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