Lanthanide metal oxide coated high-nickel ternary positive electrode material and preparation method and application thereof

Abstract

The invention belongs to the technical field of preparation of positive electrode materials, and particularly relates to a lanthanide metal oxide coated high-nickel ternary positive electrode material as well as a preparation method and application thereof. The preparation raw materials of the lanthanide metal oxide coated high-nickel ternary positive electrode material comprise a high-nickel ternary positive electrode material, a lanthanide metal oxide and graphene oxide. According to the lanthanide metal oxide coated high-nickel ternary positive electrode material provided by the invention, the preparation raw materials comprise the high-nickel ternary positive electrode material, the lanthanide metal oxide and the graphene oxide, and the lanthanide metal oxide and the graphene oxide synergistically improve the cycle life, the thermal safety and the rate capability of a battery.

Description

Technical Field

[0001] This invention belongs to the field of cathode material preparation technology, specifically relating to a lanthanide metal oxide-coated high-nickel ternary cathode material, its preparation method, and its application. Background Technology

[0002] High-nickel lanthanide metal oxide-coated high-nickel ternary cathode materials (typically referring to NCM or NCA with a nickel content ≥80%, such as NCM 811, NCA 9 / 0.5 / 0.5, etc.) are currently key materials for improving the energy density of power batteries. Although they possess high energy density, their high nickel content results in lower mechanical strength, leading to poor thermal stability, poor long-cycle performance, and short lifespan. Furthermore, microcracks and the continuously thickening interface layer that develop in the later stages of cycling severely hinder the Li-Ni alloy's performance. + The transport of electrons and other components leads to a decrease in rate performance during actual cycling. These defects hinder the use of high-nickel lanthanide metal oxide-coated high-nickel ternary cathode materials. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a lanthanide metal oxide-coated high-nickel ternary cathode material, its preparation method, and its application, thereby solving at least one aspect of the above-mentioned technical problems.

[0004] This invention is achieved through the following technical solution: In a first aspect, the present invention provides a lanthanide metal oxide-coated high-nickel ternary cathode material, the raw materials for which the preparation includes high-nickel ternary cathode material, lanthanide metal oxide and graphene oxide; The mass ratio of high-nickel ternary cathode material, lanthanide metal oxide, and graphene oxide is 1:10~15:1~3.

[0005] In some possible implementations, the general formula of the high-nickel ternary cathode material is LiMO2, where M is a nickel-cobalt-manganese ternary metal and the atomic percentage of nickel in M ​​is more than 70%.

[0006] In some possible implementations, the high-nickel ternary cathode material includes LiNi. 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.9 Co 0.05 Mn 0.05 O2, LiNi 0.95 Co 0.025 Mn 0.025 At least one of O2.

[0007] In some possible implementations, the D50 of the high-nickel ternary cathode material is 5 μm to 15 μm.

[0008] In some possible implementations, the lanthanide metal oxide includes at least one of La2O3, Ce2O3, Pr2O3, Nd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Tm2O3, Yb2O3, and Lu2O3.

[0009] In some possible implementations, the D50 of the lanthanide metal oxide is 200 nm to 300 nm.

[0010] In some possible implementations, the lateral dimensions of the graphene oxide are 1 μm to 10 μm.

[0011] Secondly, the present invention improves a method for preparing the above-mentioned lanthanide metal oxide-coated high-nickel ternary cathode material, comprising the following steps: Carbon nanotubes are grown in situ on the surface of high-nickel ternary cathode material particles and then coated. The coating process includes the following steps: loading the composite coating material precursor onto the surface of high-nickel ternary cathode material particles and then performing a reduction treatment; The precursors for composite coating materials include lanthanide metal oxides and graphene oxide.

[0012] In some possible implementations, the in-situ growth of carbon nanotubes on the surface of high-nickel ternary cathode material particles includes the following steps: Carbon nanotubes were grown on the surface of high-nickel ternary cathode material particles by loading a transition metal catalyst onto the particle surface and then using a chemical vapor phase method.

[0013] In some possible implementations, loading the composite coating material precursor onto the surface of high-nickel ternary cathode material particles includes the following steps: The mixed dispersion was subjected to ultrasonic treatment, then directional freezing, and finally freeze-drying. The raw materials for preparing the mixed dispersion include a composite coating material precursor dispersion, a high-nickel ternary cathode material after in-situ growth of carbon nanotubes, and water. The composite coating material precursor dispersion contains lanthanide metal oxides and graphene oxide.

[0014] In some possible implementations, the restoration process includes the following steps: Under a protective atmosphere, the temperature is raised to 300℃~500℃ and held.

[0015] In some possible implementations, the supported transition metal catalyst includes the following steps: After the mixture is preloaded, it is dried, activated and reduced by metals. The raw materials for preparing the mixture include transition metal salt solution and high-nickel ternary cathode material.

[0016] In some possible implementations, the mass-to-volume ratio of the high-nickel ternary cathode material to the transition metal salt solution is 1g:2ml~5ml.

[0017] In some possible implementations, the transition metal salt solution includes at least one of nickel nitrate solution, cobalt nitrate solution, and ferrocene solution.

[0018] In some possible implementations, the concentration of the transition metal salt solution is 0.01 mol / L to 0.05 mol / L.

[0019] In some possible implementations, the preload processing includes the following steps: The mixture is dispersed for 2 to 4 hours under magnetic stirring or ultrasonic conditions.

[0020] In some possible implementations, the drying process includes the following steps: Stir the mixture at 60℃~80℃.

[0021] In some possible implementations, the activation process includes the following steps: The product obtained from the drying process is then subjected to heat treatment.

[0022] In some possible implementations, the heat treatment temperature is 300°C to 400°C.

[0023] In some possible implementations, the heat treatment time is 2h to 3h.

[0024] In some possible implementations, the metal reduction process includes the following steps: Under an argon atmosphere, the activated product is heated to 500℃~700℃ and then reduced by reducing gas.

[0025] In some possible implementations, the heating rate in the metal reduction process is 5°C / min to 10°C / min.

[0026] In some possible implementations, the reducing gas in the metal reduction process includes hydrogen.

[0027] In some possible implementations, the flow rate of the reducing gas in the metal reduction process is 50 sccm to 100 sccm.

[0028] In some possible implementations, the reduction time in the metal reduction process is 15 min to 30 min; In some possible implementations, the growth of carbon nanotubes on the surface of high-nickel ternary cathode material particles using chemical vapor deposition includes the following steps: Carbon nanotubes were grown by mixing high-nickel ternary cathode material particles loaded with transition metal catalysts with a mixed gas at 500℃~700℃. The mixed gas includes a carbon source gas and a carrier gas.

[0029] In some possible implementations, the temperature of the ultrasonic treatment is 0°C to 5°C.

[0030] In some possible implementations, the ultrasonic frequency of the ultrasonic treatment is 20kHz to 25kHz.

[0031] In some possible implementations, the ultrasonic treatment time is 1 to 2 hours.

[0032] In some possible implementations, the concentration of lanthanide metal oxides in the composite coating material precursor dispersion is 6 mg / mL to 75 mg / mL.

[0033] In some possible implementations, the concentration of graphene oxide in the composite coating material precursor dispersion is 2 mg / mL to 5 mg / mL.

[0034] In some possible implementations, the directional freezing includes the following steps: The ultrasonically treated mixed dispersion was cryogenically grown in a liquid nitrogen bath.

[0035] In some possible implementations, the freeze-drying process includes the following steps: The directionally frozen products are vacuum dried at -50℃ to 0℃.

[0036] In some possible implementations, the heating rate during the reduction process is 2°C / min to 5°C / min.

[0037] In some possible implementations, the heat preservation time in the reduction process is 2h to 3h.

[0038] In some possible implementations, the protective atmosphere in the reduction process includes argon.

[0039] In some possible implementations, the flow rate of the carbon source gas is 10 sccm to 20 sccm.

[0040] In some possible implementations, the carbon source gas includes at least one of methane, ethane, and ethylene.

[0041] In some possible implementations, the flow rate of the carrier gas is 200 sccm to 300 sccm.

[0042] In some possible implementations, the carrier gas includes at least one of argon and helium.

[0043] In some possible implementations, the time for growing carbon nanotubes is 10 min to 30 min.

[0044] Thirdly, this invention provides an application of lanthanide metal oxide-coated high-nickel ternary cathode material in the field of new energy batteries.

[0045] The lanthanide metal oxide-coated high-nickel ternary cathode material provided by this invention has at least the following beneficial technical effects compared with the prior art: The present invention provides a lanthanide metal oxide-coated high-nickel ternary cathode material, the raw materials of which include high-nickel ternary cathode material, lanthanide metal oxide and graphene oxide. The lanthanide metal oxide and graphene oxide synergistically improve the cycle life, thermal safety and rate performance of the battery.

[0046] The method for preparing lanthanide metal oxide-coated high-nickel ternary cathode material provided by this invention has at least the following beneficial technical effects compared with the prior art: The present invention provides a method for preparing lanthanide metal oxide-coated high-nickel ternary cathode materials. Carbon nanotubes are grown in situ on the surface of the high-nickel ternary cathode material, causing them to intertwine and form a three-dimensional network on the surface of the high-nickel ternary cathode material particles. The composite coating material includes lanthanide metal oxide and graphene oxide, with graphene oxide serving as the framework, forming a multifunctional and robust three-dimensional network protective layer with the lanthanide metal oxide. A reduction treatment reduces graphene oxide to reduced graphene oxide, thereby significantly improving the electronic conductivity of the composite coating layer. The lanthanide metal oxide and reduced graphene oxide synergistically enhance the battery's cycle life, thermal safety, and rate performance. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described and illustrated below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments provided by this invention without inventive effort are within the scope of protection of this invention.

[0048] Obviously, the following description is merely some examples or embodiments of the present invention. Those skilled in the art can apply the present invention to other similar scenarios without any inventive effort. Furthermore, it is understood that although the effort involved in such development may be complex and lengthy, for those skilled in the art related to the content disclosed in this invention, modifications to design, manufacturing, or production based on the technical content disclosed in this invention are merely conventional technical means and should not be construed as insufficient disclosure of the present invention.

[0049] However, there may be instances where unnecessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of essentially the same structures may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to enable those skilled in the art to fully understand the invention and is not intended to limit the subject matter of the claims.

[0050] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions, and all technical features and optional technical features of the present invention can be combined with each other to form new technical solutions.

[0051] The first aspect of this invention provides a lanthanide metal oxide-coated high-nickel ternary cathode material, the raw materials of which include high-nickel ternary cathode material, lanthanide metal oxide and graphene oxide; The mass ratio of high-nickel ternary cathode material, lanthanide metal oxide and graphene oxide is 1:(10~15):(1~3).

[0052] The lanthanide metal oxide-coated high-nickel ternary cathode material provided in this embodiment of the invention is prepared from high-nickel ternary cathode material, lanthanide metal oxide and graphene oxide. The lanthanide metal oxide and graphene oxide synergistically improve the cycle life, thermal safety and rate performance of the battery.

[0053] In some embodiments, the general formula of the high-nickel ternary cathode material is LiMO2, wherein M is a nickel-cobalt-manganese ternary metal, and the atomic percentage of nickel in M ​​is more than 70%.

[0054] In some specific embodiments, the high-nickel ternary cathode material includes LiNi. 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.9 Co 0.05 Mn 0.05 O2, LiNi 0.95 Co 0.025 Mn 0.025At least one of O2.

[0055] In some embodiments, the D50 of the high-nickel ternary cathode material is 5 μm to 15 μm.

[0056] In some embodiments, the lanthanide metal oxides include at least one of La2O3, Ce2O3, Pr2O3, Nd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Tm2O3, Yb2O3, and Lu2O3.

[0057] In some embodiments, the D50 of the lanthanide metal oxide is 200 nm to 300 nm.

[0058] In some embodiments, the CAS number of graphene oxide is 2640657-49-2.

[0059] In some embodiments, the lateral dimensions of graphene oxide are 1 μm to 10 μm.

[0060] A second aspect of this invention provides a method for preparing a lanthanide metal oxide-coated high-nickel ternary cathode material, comprising the following steps: S10. Carbon nanotubes are grown in situ on the surface of high-nickel ternary cathode material particles and then coated. The coating process includes the following steps: loading the composite coating material precursor onto the surface of high-nickel ternary cathode material particles and then performing a reduction treatment; The precursors for composite coating materials include lanthanide metal oxides and graphene oxide.

[0061] The present invention provides a method for preparing lanthanide metal oxide-coated high-nickel ternary cathode materials. Carbon nanotubes are grown in situ on the surface of the high-nickel ternary cathode material, interweaving with each other to form a three-dimensional network on the surface of the high-nickel ternary cathode material particles. The composite coating material includes lanthanide metal oxide and graphene oxide, with graphene oxide serving as the framework, forming a multifunctional and robust three-dimensional network protective layer with the lanthanide metal oxide. A reduction treatment reduces graphene oxide to reduced graphene oxide, thereby significantly improving the electronic conductivity of the composite coating layer. The lanthanide metal oxide and reduced graphene oxide synergistically enhance the battery's cycle life, thermal safety, and rate performance.

[0062] In some embodiments, in step S10 above, the in-situ growth of carbon nanotubes on the surface of high-nickel ternary cathode material particles includes the following steps: S101. Carbon nanotubes are grown on the surface of high-nickel ternary cathode material particles by chemical vapor deposition after loading a transition metal catalyst onto the particle surface.

[0063] In the above steps, the transition metal catalyst catalyzes the nucleation of carbon nanotubes, which then intertwine with each other to form a network on the surface of high-nickel ternary cathode material particles.

[0064] In some embodiments, in step S101 above, supporting the transition metal catalyst includes the following steps: S1011. After preloading the mixture, it is dried, activated and reduced by metals. The raw materials for preparing the mixture include transition metal salt solution and high-nickel ternary cathode material.

[0065] In the above-mentioned supported transition metal catalyst, the pre-loading treatment allows the transition metal salt to be uniformly mixed with the high-nickel ternary cathode material, the drying process allows the transition metal salt precursor to crystallize on the surface of the high-nickel ternary cathode material particles, and the activation process allows the transition metal salt to decompose and generate corresponding nano-metal oxide particles (with smaller particle size), which are firmly attached to the surface of the high-nickel ternary cathode material particles.

[0066] In some embodiments, in step S1011 above, the mass-volume ratio of the high-nickel ternary cathode material to the transition metal salt solution is 1 g: (2 ml~5 ml).

[0067] In some embodiments, in step S1011 above, the transition metal salt solution includes at least one of nickel nitrate solution, cobalt nitrate solution, and ferrocene solution.

[0068] In some embodiments, in step S1011 above, the concentration of the transition metal salt solution is 0.01 mol / L to 0.05 mol / L.

[0069] In some embodiments, the preparation of the transition metal salt solution in step S1011 above includes the following steps: S10111. Mix the transition metal salt and solvent at a preset concentration.

[0070] In some embodiments, in step S10111 above, the solvent includes at least one of water and anhydrous ethanol.

[0071] In some embodiments, the preload processing in step S1011 above includes the following steps: S10112. Disperse the mixture for 2-4 hours under magnetic stirring or ultrasonic conditions.

[0072] In the above preloading treatment, the transition metal salt solution and the high-nickel ternary cathode material in the mixture are mixed and dispersed under magnetic stirring or ultrasonic conditions to ensure that the high-nickel ternary cathode material and the transition metal salt solution are fully mixed and in uniform contact.

[0073] In some embodiments, the drying process in step S1011 above includes the following steps: S10113. Stir the mixture at 60℃~80℃.

[0074] In the above drying process, the mixture is stirred at 60℃~80℃ until the solvent is completely evaporated, and then slowly dried to form uniform crystals of the transition metal salt precursor on the surface of the high-nickel ternary cathode material particles.

[0075] In some embodiments, the activation process in step S1011 above includes the following steps: S10114. The product obtained from the drying process is subjected to heat treatment.

[0076] In some embodiments, the heat treatment temperature in step S10114 is 300°C to 400°C. In some embodiments, the heat treatment time in step S10114 is 2 hours to 3 hours. In this case, at this heat treatment temperature and time, the transition metal oxides obtained by the decomposition of the transition metal salt form nano-sized transition metal oxide particles, thereby promoting subsequent carbon nanotube nucleation.

[0077] In some embodiments, the metal reduction process in step S1011 above includes the following steps: S10115. Under an argon atmosphere, the activated product is heated to 500℃~700℃ and then reduced by reducing gas.

[0078] In the above reduction process, a reducing gas is added after heating to 500℃~700℃ in an argon atmosphere to reduce the nano-transition metal oxide into nano-metal elemental substances, thereby enabling the high-nickel ternary cathode material to support a metal catalyst.

[0079] In some embodiments, in step S10115 above, the heating rate is 5°C / min to 10°C / min.

[0080] In some embodiments, in step S10115 above, the reducing gas includes hydrogen.

[0081] In some embodiments, in step S10115 above, the flow rate of the reducing gas is 50 sccm to 100 sccm.

[0082] sccm is a standardized unit of gas flow rate. It defines the volume of gas at a fixed temperature and pressure. 1 sccm means that 1 cubic centimeter (1 milliliter) of gas flows per minute at a temperature of 0°C and a pressure of 1 standard atmosphere.

[0083] In some embodiments, the restoration time in step S10115 is 15 min to 30 min.

[0084] In some embodiments, the growth of carbon nanotubes on the surface of high-nickel ternary cathode material particles using chemical vapor deposition in step S101 above includes the following steps: S1012. Carbon nanotubes are grown by mixing high-nickel ternary cathode material particles loaded with transition metal catalysts with a mixed gas at 500℃~700℃. The mixed gas includes a carbon source gas and a carrier gas.

[0085] In the above steps of growing carbon nanotubes, after the carbon source gas decomposes on the transition metal catalyst particles, the carbon atoms dissolve and diffuse, and finally precipitate from the other side of the catalyst particles to form carbon nanotubes. The grown carbon nanotubes intertwine with each other to form a three-dimensional network structure on the high-nickel ternary cathode material particles.

[0086] In some embodiments, in step S1012 above, the flow rate of the carbon source gas is 10 sccm to 20 sccm.

[0087] In some embodiments, in step S1012 above, the carbon source gas includes at least one of methane, ethane, and ethylene.

[0088] In some embodiments, in step S1012 above, the flow rate of the carrier gas is 200 sccm to 300 sccm.

[0089] In some embodiments, in step S1012 above, the carrier gas includes at least one of argon and helium.

[0090] In some embodiments, in step S1012 above, the time for growing carbon nanotubes is 10 min to 30 min.

[0091] In some embodiments, in step S10 above, loading the composite coating material precursor onto the surface of high-nickel ternary cathode material particles includes the following steps: S102. The mixed dispersion is subjected to ultrasonic treatment and directional freezing, followed by freeze-drying. The raw materials for preparing the mixed dispersion include a composite coating material precursor dispersion, a high-nickel ternary cathode material grown in situ with carbon nanotubes, and water. The composite coating material precursor dispersion contains lanthanide metal oxides and graphene oxide.

[0092] In some embodiments, in step S102 above, the temperature of the ultrasonic treatment is 0°C to 5°C.

[0093] In some embodiments, in step S102 above, the ultrasonic frequency of the ultrasonic treatment is 20kHz~25kHz. At this ultrasonic frequency, an extremely intense and powerful cavitation effect can be generated, resulting in localized high pressure, high temperature and strong microjets, which can effectively overcome the van der Waals forces between graphene oxide sheets, thereby achieving layer-to-layer exfoliation, and thus uniformly dispersing lanthanide metal oxides and graphene oxide in water.

[0094] In some embodiments, in step S102 above, the ultrasonic treatment time is 1h to 2h.

[0095] In some embodiments, in step S102 above, the concentration of lanthanide metal oxides in the composite coating material precursor dispersion is 6 mg / mL to 75 mg / mL.

[0096] In some embodiments, in step S102 above, the concentration of graphene oxide in the composite coating material precursor dispersion is 2 mg / mL to 5 mg / mL.

[0097] In some embodiments, in step S102 above, directional freezing includes the following steps: S1021. The ultrasonically treated mixed dispersion is cryogenically grown in a liquid nitrogen bath.

[0098] In the aforementioned directional freezing, cryo-growth in a liquid nitrogen bath allows ice crystals in the mixed dispersion to grow directionally along the temperature gradient direction, forcing graphene oxide sheets, carbon nanotubes, and high-nickel ternary cathode material particles grown in situ with carbon nanotubes to be squeezed into the gaps in the ice crystals, forming a directionally arranged channel structure.

[0099] In some embodiments, in step S1021 above, the cryo-growth time is 5h to 8h.

[0100] In some embodiments, in step S102 above, the freeze-drying process includes the following steps: S1022. Vacuum dry the directionally frozen product at -50℃ to 0℃.

[0101] In the above freeze-drying process, the product of directional freezing is in the state of ice crystals. Under vacuum at -50℃ to 0℃, the ice crystals sublimate to obtain a three-dimensional porous aerogel with graphene oxide as the skeleton, carbon nanotubes as reinforcing fibers, and high-nickel ternary cathode material with in-situ grown carbon nanotubes as functional units.

[0102] In some embodiments, in step S1022 above, the vacuum drying time is 48h~72h.

[0103] In some embodiments, the restoration process in step S10 above includes the following steps: S103. Under a protective atmosphere, heat to 300℃~500℃ and hold.

[0104] In the above reduction process, at a temperature of 300℃~500℃, the oxygen-containing functional groups in graphene oxide are thermally decomposed and removed, reducing graphene oxide to reduced graphene oxide with excellent conductivity.

[0105] In some embodiments, the protective atmosphere in step S103 described above includes argon.

[0106] In some embodiments, in step S103 above, the heating rate is 2°C / min to 5°C / min.

[0107] In some embodiments, the heat preservation time in step S103 is 2h to 3h.

[0108] The following description, in conjunction with specific embodiments, provides further details. For ease of explanation, the following embodiments and comparative examples involve: (1) The CAS number of graphene oxide is 2640657-49-2.

[0109] (2) The lateral dimensions of graphene oxide are 1 μm to 10 μm.

[0110] Example 1 Example 1 provides a lanthanide metal oxide-coated high-nickel ternary cathode material, prepared from LiNi. 0.8 Co 0.1 Mn 0.1 O2 (NCM811), ethylene, La2O3 and graphene oxide; among which, the D50 of La2O3 is 300nm.

[0111] This embodiment also provides a method for preparing the lanthanide metal oxide-coated high-nickel ternary cathode material provided in this embodiment, the steps of which are as follows: E10. Growth of carbon nanotubes E101. Preparation of mixtures NCM811 and ferrocene solution were mixed at a mass-to-volume ratio of 1g:3ml; wherein the concentration of the ferrocene solution was 0.03mol / L, and it was a mixture of ferrocene and anhydrous ethanol.

[0112] E102. Preload Processing The mixture was dispersed for 3 hours under magnetic stirring or ultrasonic conditions.

[0113] E103. Drying treatment Stir the mixture at 70°C until the solvent is completely evaporated.

[0114] E104. Activation Treatment The product obtained by drying was heat-treated at 380℃ for 3 hours.

[0115] E105. Metal Reduction Treatment Under an argon atmosphere, the activated product was heated to 600°C at a heating rate of 8°C / min and then reduced with hydrogen for 20 min. The hydrogen flow rate was 80 sccm, resulting in high-nickel ternary cathode material particles supported on a transition metal catalyst.

[0116] E106. Carbon nanotubes grown on the surface of high-nickel ternary cathode material particles using chemical vapor deposition. At 600℃, high-nickel ternary cathode material particles loaded with transition metal catalyst were mixed with a mixed gas to grow carbon nanotubes for 20 min, thus obtaining high-nickel ternary cathode material with in-situ grown carbon nanotubes. The mixed gas consists of ethylene and argon, with an ethylene flow rate of 15 sccm and an argon flow rate of 250 sccm.

[0117] E20. Encapsulation E201. Preparation of Mixed Dispersions The high-nickel ternary cathode material after in-situ carbon nanotube growth, lanthanide metal oxide, and graphene oxide were mixed with a composite coating material precursor dispersion prepared according to a preset mass ratio of 1:13:2. The dispersion was obtained by mixing the high-nickel ternary cathode material after in-situ carbon nanotube growth with the composite coating material precursor dispersion. The concentration of lanthanide metal oxide was 19.55 mg / mL and the concentration of graphene oxide was 3 mg / mL.

[0118] E202. Ultrasonic treatment The mixed dispersion was subjected to ultrasonic treatment at 0°C for 2 hours; wherein the ultrasonic frequency was 20 kHz.

[0119] E203. Directional Freezing The ultrasonically treated mixed dispersion was frozen and grown in a liquid nitrogen bath for 7 hours.

[0120] E204. Freeze-drying treatment The directionally frozen product was vacuum dried at -50°C for 72 hours.

[0121] E205. Reduction Process Under an argon atmosphere, the temperature was increased to 400°C at a heating rate of 4°C / min and held for 3 hours to obtain the lanthanide metal oxide-coated high-nickel ternary cathode material of this embodiment.

[0122] Example 2 Example 2 provides a lanthanide metal oxide-coated high-nickel ternary cathode material, with the same raw materials as in Example 1.

[0123] This embodiment also provides a method for preparing a lanthanide metal oxide-coated high-nickel ternary cathode material, the steps of which are basically the same as those in Example 1, except that: In step E106, the temperature for growing carbon nanotubes is 500℃, the time is 30 min, the flow rate of ethylene is 20 sccm, and the flow rate of argon is 300 sccm.

[0124] Example 3 Example 3 provides a lanthanide metal oxide-coated high-nickel ternary cathode material, with the same raw materials as in Example 1.

[0125] This embodiment also provides a method for preparing a lanthanide metal oxide-coated high-nickel ternary cathode material, the steps of which are basically the same as those in Example 1, except that: In step E106, the temperature for growing carbon nanotubes is 700℃, the time is 10 min, the flow rate of ethylene is 10 sccm, and the flow rate of argon is 200 sccm.

[0126] Example 4 Example 4 provides a lanthanide metal oxide-coated high-nickel ternary cathode material, with the same raw materials as in Example 1.

[0127] This embodiment also provides a method for preparing a lanthanide metal oxide-coated high-nickel ternary cathode material, the steps of which are basically the same as those in Example 1, except that: In step E204, the directionally frozen product is vacuum dried at 0°C for 62 hours.

[0128] Example 5 Example 5 provides a lanthanide metal oxide-coated high-nickel ternary cathode material, with the same raw materials as in Example 1.

[0129] This embodiment also provides a method for preparing a lanthanide metal oxide-coated high-nickel ternary cathode material, the steps of which are basically the same as those in Example 1, except that: In step E204, the directionally frozen product is vacuum dried at -30°C for 48 hours.

[0130] Example 6 Example 6 provides a lanthanide metal oxide-coated high-nickel ternary cathode material, prepared from LiNi. 0.95 Co 0.025 Mn 0.025 O2, ethane, Ce2O3 and graphene oxide; among which, the D50 of Ce2O3 is 200 nm.

[0131] This embodiment also provides a method for preparing a lanthanide metal oxide-coated high-nickel ternary cathode material, the steps of which are basically the same as those in Example 1, except that: The raw material for preparation is LiNi 0.95 Co 0.025 Mn 0.025 O2, ethane, Ce2O3 and graphene oxide; among which, the D50 of Ce2O3 is 200 nm.

[0132] Comparative Example 1 Comparative Example 1 provides a method for preparing a lanthanide metal oxide-coated high-nickel ternary cathode material, the steps of which are basically the same as those in Example 1, except that: In step E106, the temperature for growing carbon nanotubes is 400℃, the time is 50 min, the flow rate of ethylene is 30 sccm, and the flow rate of argon is 100 sccm.

[0133] Comparative Example 2 Comparative Example 2 provides a method for preparing a lanthanide metal oxide-coated high-nickel ternary cathode material, the steps of which are basically the same as those in Example 1, except that: In step E106, the temperature for growing carbon nanotubes is 800℃, the time is 10 min, the flow rate of ethylene is 5 sccm, and the flow rate of argon is 300 sccm.

[0134] Comparative Example 3 Comparative Example 3 provides a method for preparing a lanthanide metal oxide-coated high-nickel ternary cathode material, the steps of which are basically the same as those in Example 1, except that: No directional freezing step is performed; the freeze-drying process is carried out directly.

[0135] To verify the advancement of the lanthanide metal oxide-coated high-nickel ternary cathode material and its preparation method provided in this embodiment of the invention, the first discharge capacity (0.2C) and capacity retention rate (1C) after 2500 cycles were tested on the lanthanide metal oxide-coated high-nickel ternary cathode materials prepared in this embodiment and the comparative example. The results are shown in Table 1 below.

[0136] Table 1

[0137] From Table 1 above, at least the following conclusions can be drawn: This invention provides a method for preparing a lanthanide metal oxide-coated high-nickel ternary cathode material. First, carbon nanotubes are grown on the surface of the high-nickel ternary cathode material, allowing them to interweave and form a three-dimensional network on the surface of the high-nickel ternary cathode material particles. Then, lanthanide metal oxide and graphene oxide are coated at ultra-low temperatures, allowing graphene oxide to act as a framework and work with lanthanide metal oxide to construct a multifunctional and robust three-dimensional network protective layer, which synergistically improves the battery's cycle life, thermal safety, and rate performance.

[0138] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. A lanthanide metal oxide-coated high-nickel ternary cathode material, characterized in that, The raw materials used in the preparation include high-nickel ternary cathode materials, lanthanide metal oxides, and graphene oxide; The mass ratio of high-nickel ternary cathode material, lanthanide metal oxide, and graphene oxide is 1:10~15:1~3.

2. The lanthanide metal oxide-coated high-nickel ternary cathode material according to claim 1, characterized in that, It satisfies at least one of the following characteristics (1) to (6): (1) The general formula of the high-nickel ternary cathode material is LiMO2, wherein M is a nickel-cobalt-manganese ternary metal, and the atomic percentage of nickel in M ​​is more than 70%; (2) The high-nickel ternary cathode material includes LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.9 Co 0.05 Mn 0.05 O2, LiNi 0.95 Co 0.025 Mn 0.025 At least one of O2; (3) The D50 of the high-nickel ternary cathode material is 5μm~15μm; (4) The lanthanide metal oxides include at least one of La2O3, Ce2O3, Pr2O3, Nd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Tm2O3, Yb2O3, and Lu2O3; (5) The D50 of the lanthanide metal oxide is 200 nm to 300 nm; (6) The transverse dimension of the graphene oxide is 1 μm to 10 μm.

3. A method for preparing a lanthanide metal oxide-coated high-nickel ternary cathode material as described in claim 1 or 2, characterized in that, Includes the following steps: Carbon nanotubes are grown in situ on the surface of high-nickel ternary cathode material particles and then coated. The coating process includes the following steps: loading the composite coating material precursor onto the surface of high-nickel ternary cathode material particles and then performing a reduction treatment; The precursors for composite coating materials include lanthanide metal oxides and graphene oxide.

4. The method for preparing lanthanide metal oxide-coated high-nickel ternary cathode material according to claim 3, characterized in that, It satisfies at least one of the following characteristics (1) to (3): (1) The in-situ growth of carbon nanotubes on the surface of high-nickel ternary cathode material particles includes the following steps: Carbon nanotubes were grown on the surface of high-nickel ternary cathode material particles after loading a transition metal catalyst onto the particles using a chemical vapor phase method. (2) Loading the composite coating material precursor onto the surface of high-nickel ternary cathode material particles includes the following steps: The mixed dispersion was subjected to ultrasonic treatment, then directional freezing, and finally freeze-drying. The raw materials for preparing the mixed dispersion include a composite coating material precursor dispersion, a high-nickel ternary cathode material after in-situ growth of carbon nanotubes, and water. The composite coating material precursor dispersion contains lanthanide metal oxides and graphene oxide. (3) The reduction process includes the following steps: Under a protective atmosphere, the temperature is raised to 300℃~500℃ and held.

5. The method for preparing lanthanide metal oxide-coated high-nickel ternary cathode material according to claim 4, characterized in that, The supported transition metal catalyst includes the following steps: After the mixture is preloaded, it is dried, activated and reduced by metals. The raw materials for preparing the mixture include transition metal salt solution and high-nickel ternary cathode material.

6. The method for preparing lanthanide metal oxide-coated high-nickel ternary cathode material according to claim 5, characterized in that, It satisfies at least one of the following characteristics (1) to (9): (1) The mass-to-volume ratio of the high-nickel ternary cathode material to the transition metal salt solution is 1g:2ml~5ml; (2) The transition metal salt solution includes at least one of nickel nitrate solution, cobalt nitrate solution, and ferrocene solution; (3) The concentration of the transition metal salt solution is 0.01 mol / L to 0.05 mol / L; (4) The preload processing includes the following steps: The mixture is dispersed for 2 to 4 hours under magnetic stirring or ultrasonic conditions; (5) The drying process includes the following steps: Stir the mixture at 60℃~80℃; (6) The activation process includes the following steps: The product obtained from the drying process is then subjected to heat treatment. (7) The temperature of the heat treatment is 300℃~400℃; (8) The heat treatment time is 2h~3h; (9) The metal reduction treatment includes the following steps: Under an argon atmosphere, the activated product is heated to 500℃~700℃ and then reduced by reducing gas.

7. The method for preparing lanthanide metal oxide-coated high-nickel ternary cathode material according to claim 6, characterized in that, Satisfying at least one of the following features (1) to (4): (1) In the metal reduction treatment, the heating rate is 5℃ / min~10℃ / min; (2) In the metal reduction process, the reducing gas includes hydrogen; (3) In the metal reduction process, the flow rate of the reducing gas is 50 sccm to 100 sccm; (4) In the metal reduction treatment, the reduction time is 15 min to 30 min.

8. The method for preparing lanthanide metal oxide-coated high-nickel ternary cathode material according to claim 4, characterized in that, It satisfies at least one of the following characteristics (1) to (11): (1) The method of growing carbon nanotubes on the surface of high-nickel ternary cathode material particles by chemical vapor deposition includes the following steps: Carbon nanotubes were grown by mixing high-nickel ternary cathode material particles loaded with transition metal catalysts with a mixed gas at 500℃~700℃. The mixed gas includes a carbon source gas and a carrier gas; (2) The temperature of the ultrasonic treatment is 0℃~5℃; (3) The ultrasonic frequency of the ultrasonic treatment is 20kHz~25kHz; (4) The duration of the ultrasonic treatment is 1 to 2 hours; (5) The concentration of lanthanide metal oxide in the precursor dispersion of the composite coating material is 6 mg / mL to 75 mg / mL; (6) The concentration of graphene oxide in the composite coating material precursor dispersion is 2 mg / mL to 5 mg / mL; (7) The directional freezing includes the following steps: The ultrasonically treated mixed dispersion was cryogenically grown in a liquid nitrogen bath. (8) The freeze-drying process includes the following steps: Vacuum-dry the directionally frozen products at -50℃ to 0℃; (9) In the reduction process, the heating rate is 2℃ / min to 5℃ / min; (10) In the reduction process, the heat preservation time is 2h~3h; (11) In the reduction process, the protective atmosphere includes argon.

9. The method for preparing lanthanide metal oxide-coated high-nickel ternary cathode material according to claim 8, characterized in that, It satisfies at least one of the following characteristics (1) to (5): (1) The flow rate of the carbon source gas is 10 sccm to 20 sccm; (2) The carbon source gas includes at least one of methane, ethane, and ethylene; (3) The flow rate of the carrier gas is 200 sccm~300 sccm; (4) The carrier gas includes at least one of argon and helium; (5) The growth time of the carbon nanotubes is 10 min to 30 min.

10. The application of a lanthanide metal oxide-coated high-nickel ternary cathode material as described in claim 1 or 2 in the field of new energy batteries.

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