Modified lithium lanthanum zirconium oxygen material, and preparation method and application thereof

Abstract

This invention discloses a modified lithium lanthanum zirconium oxide material, its preparation method, and its application, relating to the field of solid electrolyte material preparation and application. The modified lithium lanthanum zirconium oxide material of this invention comprises lithium lanthanum zirconium oxide material and a TiCN / W-Cu composite material, with the TiCN / W-Cu composite material coating the outer surface of the lithium lanthanum zirconium oxide material. Coating the surface of the lithium lanthanum zirconium oxide material with the TiCN / W-Cu composite material effectively increases the ionic conductivity of the lithium lanthanum zirconium oxide material and also helps improve the material's processing performance, making it suitable as a solid electrolyte for use in lithium-ion solid-state batteries.

Description

Technical Field

[0001] This invention relates to the field of solid electrolyte material preparation and application technology, and more specifically, to a modified lithium lanthanum zirconium oxide material, its preparation method and application. Background Technology

[0002] Lithium-ion batteries have gradually replaced nickel-metal hydride and nickel-cadmium batteries due to their advantages such as environmental friendliness, low pollution, long cycle life, and lack of memory effect. However, for lithium-ion batteries to achieve larger and higher energy outputs, their safety must be guaranteed. For lithium-ion batteries, safety hazards mainly stem from reactions in the liquid electrolyte under conditions such as overcharging, thermal shock, and short circuits, which can cause battery swelling, fire, or even explosion, directly threatening human health and equipment safety.

[0003] Solid-state electrolytes can overcome the aforementioned safety issues of liquid electrolytes. Solid-state electrolytes achieve conductivity through the migration of conductive ions; the faster the ion migration rate, the better the conductivity of the electrolyte. Among these, lithium lanthanum zirconium oxide (Li7La3Zr2O) is a good example. 12 LLZO solid electrolytes are highly competitive among inorganic solid electrolytes due to their advantages such as high ionic conductivity, wide electrochemical window, good stability to lithium metal anodes, and good interfacial compatibility with high-potential cathode materials.

[0004] However, LLZO exposed to moisture will undergo Li + / H + During the exchange process, Li2CO3 is generated on the surface, which leads to a decrease in the ionic conductivity of the material, further limiting the development of LLZO. Summary of the Invention

[0005] The main objective of this invention is to provide a modified lithium lanthanum zirconium oxide material, its preparation method, and its application, in order to solve the problem that the ionic conductivity of lithium lanthanum zirconium oxide materials is easily affected by the environment in the prior art.

[0006] To achieve the above objectives, according to a first aspect of the present invention, a modified lithium lanthanum zirconium oxide material is provided, the modified lithium lanthanum zirconium oxide material comprising lithium lanthanum zirconium oxide material and TiCN / W-Cu composite material, wherein the TiCN / W-Cu composite material coats the outer surface of the lithium lanthanum zirconium oxide material.

[0007] Furthermore, the mass ratio of the above-mentioned lithium lanthanum zirconium oxide material to the TiCN / W-Cu composite material is 100:(0.1-0.9).

[0008] Furthermore, the molar ratio of Li, La, and Zr elements in the above-mentioned lithium lanthanum zirconium oxide material is (7.0-7.1):3:2; the mass ratio of TiCN, W, and Cu in the TiCN / W-Cu composite material is (2-3):(76.5-85.5):(13.5-15.5).

[0009] Furthermore, the aforementioned TiCN / W-Cu composite material is obtained by coating the surface of the lithium lanthanum zirconium oxide material with a mixed powder containing copper, tungsten, and titanium carbonitride using a spark plasma sintering process.

[0010] According to a second aspect of the present invention, a method for preparing the above-mentioned modified lithium lanthanum zirconium oxide material is provided, the method comprising the following steps:

[0011] S1, Weigh out lithium source, lanthanum source and zirconium source, and disperse them in a dispersant to obtain a dispersion. Ball mill, dry, sinter and cool the dispersion to obtain lithium lanthanum zirconium oxide material;

[0012] S2, lithium lanthanum zirconium oxide material, TiCN, copper-tungsten composite powder, and copper powder are mixed to obtain a mixed powder. The mixed powder is ball-milled and then subjected to spark plasma sintering to obtain modified lithium lanthanum zirconium oxide material. The copper-tungsten composite powder is copper-coated tungsten composite powder or a mixed powder of copper powder and tungsten powder.

[0013] Further, in S1, the lithium source includes at least one of lithium carbonate, lithium hydroxide, and lithium nitrate; and / or, the lanthanum source includes at least one of lanthanum oxide, lanthanum hydroxide, and lanthanum nitrate; and / or, the zirconium source includes at least one of zirconium oxide and zirconium hydroxide; and / or, the dispersant includes at least one of anhydrous ethanol and isopropanol, and the solid content of the dispersion is 30%-50%.

[0014] Furthermore, in S2, the copper-tungsten composite powder is a copper-coated tungsten composite powder, and the molar ratio of tungsten to copper in the copper-coated tungsten composite powder is (2-3):1.

[0015] Further, in S1, the ball mill rotation speed is 200-600 rpm, and the ball milling time is 2-4 hours; and / or

[0016] The drying temperature is 60-90℃, and the drying time is 4-10 hours; and / or

[0017] The sintering temperature is 900-1100℃, the sintering time is 10-20h, and the sintering atmosphere is air.

[0018] Furthermore, in S2, the ball mill rotation speed is 100-300 rpm, and the ball milling time is 8-16 h; and / or

[0019] The conditions for spark plasma sintering are: temperature of 1100-1200℃, time of 3-5min, pressure of 30-50MPa, and heating rate of 35-50℃ / s. During spark plasma sintering, the powder is placed in a graphite mold and sintered in an inert gas.

[0020] According to a third aspect of the present invention, an application of the above-described modified lithium lanthanum zirconium oxide material in a solid electrolyte is provided.

[0021] According to a fourth aspect of the present invention, the application of the above-described modified lithium lanthanum zirconium oxide material in the preparation of lithium-ion solid-state batteries is provided.

[0022] By applying the technical solution of this invention, the structure of lithium lanthanum zirconium oxide material is optimized by coating the outer surface of the lithium lanthanum zirconium oxide material with TiCN / W-Cu composite material, which can effectively slow down the reaction between the lithium lanthanum zirconium oxide material and air, thus helping to improve the ionic conductivity of the lithium lanthanum zirconium oxide material and expand its application range. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0024] As described in the background section of this invention, existing technologies suffer from the problem that LLZO materials are susceptible to environmental influences, leading to a decrease in their ionic conductivity. To address this issue, in a typical embodiment of this invention, a modified lithium lanthanum zirconium oxide material is provided. This modified lithium lanthanum zirconium oxide material comprises lithium lanthanum zirconium oxide material and a TiCN / W-Cu composite material, wherein the TiCN / W-Cu composite material coats the outer surface of the lithium lanthanum zirconium oxide material.

[0025] Coating LLZO material with TiCN / W-Cu composite material can isolate LLZO material from air, preventing it from reacting with moisture in the air to form lithium carbonate and reduce its ionic conductivity. At the same time, TiCN / W-Cu composite material does not affect the ionic conductivity of LLZO material itself, thus solving the problem that LLZO material is easily affected by external factors, leading to a decrease in ionic conductivity.

[0026] In a preferred embodiment of the present invention, the mass ratio of the above-mentioned lithium lanthanum zirconium oxide material to the TiCN / W-Cu composite material is 100:(0.1-0.9). Meeting this requirement can effectively improve the ionic conductivity of the modified LLZO material; however, the improvement effect is relatively low when the proportion of the TiCN / W-Cu composite material is too high.

[0027] In a preferred embodiment of the present invention, the molar ratio of Li, La, and Zr in the above-mentioned lithium lanthanum zirconium oxide material is (7.0-7.1):3:2; the mass ratio of TiCN, W, and Cu in the TiCN / W-Cu composite material is (2-3):(76.5-85.5):(13.5-15.5). When the ratio of Li, La, and Zr meets the above-mentioned limitations, a LLZO material with fewer defects and higher ionic conductivity can be prepared. When the mass ratio of TiCN, W, and Cu in the TiCN / W-Cu composite material meets the above-mentioned limitations, the modified lithium lanthanum zirconium oxide material has even higher ionic conductivity.

[0028] In a preferred embodiment of the present invention, the above-mentioned TiCN / W-Cu composite material is prepared by coating the surface of the lithium lanthanum zirconium oxide material with a mixed powder containing copper, tungsten, and titanium carbonitride through spark plasma sintering. Coating the lithium lanthanum zirconium oxide material with the TiCN / W-Cu composite material via spark plasma sintering can improve the crystallinity of the lithium lanthanum zirconium oxide material through secondary sintering, reduce structural defects, and facilitate the provision of more regular and ordered lithium-ion transport channels. Furthermore, this method helps to increase the density of the material, which in turn contributes to further improving the ionic conductivity.

[0029] In another typical embodiment of the present invention, a method for preparing the above-mentioned modified lithium lanthanum zirconium oxide material is provided, the method comprising the following steps:

[0030] S1, Weigh out lithium source, lanthanum source and zirconium source, and disperse them in a dispersant to obtain a dispersion. Ball mill, dry, sinter and cool the dispersion to obtain lithium lanthanum zirconium oxide material;

[0031] S2, lithium lanthanum zirconium oxide material, TiCN, copper-tungsten composite powder, and copper powder are mixed to obtain a mixed powder. The mixed powder is ball-milled and then subjected to spark plasma sintering to obtain modified lithium lanthanum zirconium oxide material. The copper-tungsten composite powder is copper-coated tungsten composite powder or a mixed powder of copper powder and tungsten powder.

[0032] The spark plasma sintering method has an extremely fast heating rate, which can form TiCN / W-Cu composite materials on the outer surface of LLZO materials by using TiCN, copper-tungsten composite powder, and copper powder, thus isolating LLZO from air. In addition, it can perform secondary sintering of LLZO materials to improve their crystallinity and help to improve ionic conductivity.

[0033] Non-limiting, in S1, the lithium source includes at least one of lithium carbonate, lithium hydroxide, and lithium nitrate; and / or, the lanthanum source includes at least one of lanthanum oxide, lanthanum hydroxide, and lanthanum nitrate; and / or, the zirconium source includes at least one of zirconium oxide and zirconium hydroxide; and / or, the dispersant includes at least one of anhydrous ethanol and isopropanol, and the solid content of the dispersion is 30%-50%.

[0034] In a preferred embodiment of the present invention, in S2, the copper-tungsten composite powder is a copper-coated tungsten composite powder, wherein the molar ratio of tungsten to copper in the copper-coated tungsten composite powder is (2-3):1. When the above limitation is met, the distribution of each component in the prepared modified lithium lanthanum zirconium oxide material is more uniform, and at the same time, the modified lithium lanthanum zirconium oxide material has better ionic conductivity.

[0035] In a preferred embodiment of the present invention, in S1,

[0036] The ball mill rotates at 200-600 rpm, and the milling time is 2-4 hours; and / or

[0037] The drying temperature is 60-90℃, and the drying time is 4-10 hours; and / or

[0038] The sintering temperature is 900-1100℃, the sintering time is 10-20h, and the sintering atmosphere is air.

[0039] In a preferred embodiment of the present invention, in S2, the ball milling speed is 100-300 rpm, and the ball milling time is 8-16 h; and / or

[0040] The conditions for spark plasma sintering are: temperature of 1100-1200℃, time of 3-5min, pressure of 30-50MPa, and heating rate of 35-50℃ / s. During spark plasma sintering, the powder is placed in a graphite mold and sintered in an inert gas.

[0041] When the preparation conditions meet the above limitations, the prepared modified lithium lanthanum zirconium oxide material has a regular structure, high density, and good ionic conductivity.

[0042] In another typical embodiment of the present invention, the application of the above-mentioned modified lithium lanthanum zirconium oxide material in a solid electrolyte is provided.

[0043] In another typical embodiment of the present invention, the application of the above-mentioned modified lithium lanthanum zirconium oxide material in the preparation of lithium-ion solid-state batteries is also provided.

[0044] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0045] Copper-coated tungsten composite powder: Weigh tungsten powder and anhydrous copper sulfate according to the molar ratio of W to Cu of (2-3):1. Disperse anhydrous copper sulfate, potassium sodium phenolate, and disodium ethylenediaminetetraacetate in polyethylene glycol, then add formaldehyde as a reducing agent. Adjust the pH to 11-13 with NaOH to obtain the plating solution. Wash the tungsten powder with deionized water until neutral and add it to the plating solution. Maintain the plating solution at a constant temperature of 55℃ using a water bath and perform magnetic stirring. Continuously add NaOH during the reaction. The reaction ends when the plating solution changes from blue to clear. Wash the reacted powder with deionized water until neutral, ultrasonically clean and disperse the particles with anhydrous ethanol, and then dry it in a drying oven at 50℃ for 6 hours to obtain copper-coated tungsten composite powder.

[0046] Example 1

[0047] An embodiment of the modified lithium lanthanum zirconium oxide material of the present invention includes the following steps in the preparation method of the modified lithium lanthanum zirconium oxide material:

[0048] S1. Lithium carbonate, lanthanum oxide, and zirconium oxide were weighed according to the molar ratio of Li, La, and Zr elements of 7.01:3:2. They were dispersed in anhydrous ethanol to form a dispersion with a solid content of 30%. The dispersion was then ball-milled at 200 rpm for 2 hours, dried at 60°C for 4 hours, and finally sintered at 900°C for 10 hours. After natural cooling, lithium lanthanum zirconium oxide material was obtained.

[0049] S2, copper-coated tungsten composite powder (the molar ratio of tungsten to copper is 2:1), copper powder, and titanium carbonitride were weighed at a mass ratio of 90:2:3 to obtain a mixed powder sample. Then, the lithium lanthanum zirconium oxide material prepared in S1 was added to the mixed powder sample to obtain a mixed powder. The mass ratio of the mixed powder sample to the lithium lanthanum zirconium oxide material was 0.1:100. The mixed powder was dry ball-milled at 100 rpm for 8 hours. Then, the mixed powder was placed in a graphite mold with a diameter of 30 mm, sintered at a pressure of 30 MPa, a heating rate of 35 °C / s, and placed in high-purity argon gas. The mixture was then subjected to discharge plasma sintering at 1100 °C for 3 minutes to obtain the modified lithium lanthanum zirconium oxide material.

[0050] Example 2

[0051] An embodiment of the modified lithium lanthanum zirconium oxide material of the present invention includes the following steps in the preparation method of the modified lithium lanthanum zirconium oxide material:

[0052] S1. Lithium hydroxide, lanthanum hydroxide, and zirconium hydroxide were weighed according to the molar ratio of Li, La, and Zr elements of 7.02:3:2. They were dispersed in isopropanol to form a dispersion with a solid content of 35%. The dispersion was then ball-milled at 300 rpm for 2.5 h, dried at 65 °C for 5 h, and finally sintered in air at 950 °C for 12 h. After natural cooling, lithium lanthanum zirconium oxide material was obtained.

[0053] S2, copper-coated tungsten composite powder (the molar ratio of tungsten to copper is 2.2:1), copper powder, and titanium carbonitride were weighed at a mass ratio of 92:2.5:2 to obtain a mixed powder sample. Then, the lithium lanthanum zirconium oxide material prepared in S1 was added to the mixed powder sample to obtain a mixed powder. The mass ratio of the mixed powder sample to the lithium lanthanum zirconium oxide material was 0.3:100. The mixed powder was dry ball-milled at 150 rpm for 10 h. Then, the mixed powder was placed in a graphite mold with a diameter of 30 mm, sintered at a pressure of 35 MPa, a heating rate of 40 °C / s, and placed in high-purity argon gas. The mixture was then subjected to discharge plasma sintering at 1150 °C for 3.5 min to obtain the modified lithium lanthanum zirconium oxide material.

[0054] Example 3

[0055] An embodiment of the modified lithium lanthanum zirconium oxide material of the present invention includes the following steps in the preparation method of the modified lithium lanthanum zirconium oxide material:

[0056] S1. Lithium hydroxide, lanthanum hydroxide, and zirconium hydroxide were weighed according to the molar ratio of Li, La, and Zr elements of 7.0:3:2. They were dispersed in isopropanol to form a dispersion with a solid content of 40%. The dispersion was then ball-milled at 350 rpm for 3 hours, dried at 75°C for 7 hours, and finally sintered in air at 1000°C for 15 hours. After natural cooling, lithium lanthanum zirconium oxide material was obtained.

[0057] S2, copper-coated tungsten composite powder (the molar ratio of tungsten to copper is 2.5:1), copper powder, and titanium carbonitride were weighed at a mass ratio of 92.5:3:2 to obtain a mixed powder sample. Then, the lithium lanthanum zirconium oxide material prepared in S1 was added to the mixed powder sample to obtain a mixed powder. The mass ratio of the mixed powder sample to the lithium lanthanum zirconium oxide material was 0.5:100. The mixed powder was dry ball-milled at 200 rpm for 12 h. Then, the mixed powder was placed in a graphite mold with a diameter of 30 mm, sintered at a pressure of 40 MPa and a heating rate of 43 °C / s, and placed in high-purity argon gas for discharge plasma sintering at 1150 °C for 4 min to obtain the modified lithium lanthanum zirconium oxide material.

[0058] Example 4

[0059] An embodiment of the modified lithium lanthanum zirconium oxide material of the present invention includes the following steps in the preparation method of the modified lithium lanthanum zirconium oxide material:

[0060] S1. Lithium hydroxide, lanthanum hydroxide, and zirconium hydroxide were weighed according to the molar ratio of Li, La, and Zr elements of 7.08:3:2. They were dispersed in isopropanol to form a dispersion with a solid content of 45%. The dispersion was then ball-milled at 450 rpm for 2.5 h, dried at 65 °C for 9 h, and finally sintered in air at 1050 °C for 18 h. After natural cooling, lithium lanthanum zirconium oxide material was obtained.

[0061] S2, copper-coated tungsten composite powder (the molar ratio of tungsten to copper is 2.4:1), copper powder, and titanium carbonitride were weighed at a mass ratio of 93:2:2.5 to obtain a mixed powder sample. Then, the lithium lanthanum zirconium oxide material prepared in S1 was added to the mixed powder sample to obtain a mixed powder. The mass ratio of the mixed powder sample to the lithium lanthanum zirconium oxide material was 0.75:100. The mixed powder was dry ball-milled at 250 rpm for 14 h. Then, the mixed powder was placed in a graphite mold with a diameter of 30 mm, sintered at a pressure of 45 MPa and a heating rate of 38 °C / s, and placed in high-purity argon gas for discharge plasma sintering at 1100 °C for 4.5 min to obtain the modified lithium lanthanum zirconium oxide material.

[0062] Example 5

[0063] An embodiment of the modified lithium lanthanum zirconium oxide material of the present invention includes the following steps in the preparation method of the modified lithium lanthanum zirconium oxide material:

[0064] S1. Lithium carbonate, lanthanum oxide, and zirconium oxide were weighed according to the molar ratio of Li, La, and Zr elements of 7.06:3:2. They were dispersed in anhydrous ethanol to form a dispersion with a solid content of 45%. The dispersion was then ball-milled at 250 rpm for 4 hours, dried at 60°C for 4.5 hours, and finally sintered in air at 950°C for 13 hours. After natural cooling, lithium lanthanum zirconium oxide material was obtained.

[0065] S2, copper-coated tungsten composite powder (the molar ratio of tungsten to copper is 2.7:1), copper powder, and titanium carbonitride were weighed at a mass ratio of 93:3.5:2.5 to obtain a mixed powder sample. Then, the lithium lanthanum zirconium oxide material prepared in S1 was added to the mixed powder sample to obtain a mixed powder. The mass ratio of the mixed powder sample to the lithium lanthanum zirconium oxide material was 0.75:100. The mixed powder was dry ball-milled at 200 rpm for 12 h. Then, the mixed powder was placed in a graphite mold with a diameter of 30 mm, sintered at a pressure of 45 MPa and a heating rate of 45 °C / s, and placed in high-purity argon gas for discharge plasma sintering at 1100 °C for 4.5 min to obtain the modified lithium lanthanum zirconium oxide material.

[0066] Example 6

[0067] An embodiment of the modified lithium lanthanum zirconium oxide material of the present invention includes the following steps in the preparation method of the modified lithium lanthanum zirconium oxide material:

[0068] S1. Lithium carbonate, lanthanum oxide, and zirconium oxide were weighed according to the molar ratio of Li, La, and Zr elements of 7.1:3:2. They were dispersed in anhydrous ethanol to form a dispersion with a solid content of 50%. The dispersion was then ball-milled at 600 rpm for 4 hours, dried at 90°C for 10 hours, and finally sintered at 1100°C in air atmosphere for 20 hours. After natural cooling, lithium lanthanum zirconium oxide material was obtained.

[0069] S2, copper-coated tungsten composite powder (the molar ratio of tungsten to copper is 3:1), copper powder, and titanium carbonitride were weighed at a mass ratio of 95:4:3 to obtain a mixed powder sample. Then, the lithium lanthanum zirconium oxide material prepared in S1 was added to the mixed powder sample to obtain a mixed powder. The mass ratio of the mixed powder sample to the lithium lanthanum zirconium oxide material was 0.9:100. The mixed powder was dry ball-milled at 300 rpm for 16 h. Then, the mixed powder was placed in a graphite mold with a diameter of 30 mm, sintered at a pressure of 50 MPa and a heating rate of 50 °C / s, and placed in high-purity argon gas for discharge plasma sintering at 1200 °C for 5 min to obtain the modified lithium lanthanum zirconium oxide material.

[0070] Example 7

[0071] This invention provides an embodiment of the modified lithium lanthanum zirconium oxide material. The difference between the preparation method of the modified lithium lanthanum zirconium oxide material in this embodiment and that in Example 3 is that the mass ratio of the mixed powder sample to the lithium lanthanum zirconium oxide material in S2 is 1.1:100.

[0072] Example 8

[0073] This invention provides an embodiment of the modified lithium lanthanum zirconium oxide material. The difference between the preparation method of the modified lithium lanthanum zirconium oxide material in this embodiment and that in embodiment 3 is that, in S2, copper-coated tungsten composite powder (the molar ratio of tungsten to copper is 2:1), copper powder, and titanium carbonitride are weighed at a mass ratio of 90:2:4 to obtain a mixed powder sample.

[0074] Comparative Example 1

[0075] Comparative Example 1 is a lithium lanthanum zirconium oxide material, which is prepared by the same method as S1 in Example 3.

[0076] Comparative Example 2

[0077] Comparative Example 2 is a modified lithium lanthanum zirconium oxide material. Its preparation method differs from that of Example 3 in that, in S2, the mixed powder sample does not contain copper-coated tungsten composite powder, and the mass ratio of TiCN and Cu elements remains unchanged.

[0078] Performance testing

[0079] The density of the examples and comparative examples was determined using the Archimedes' displacement method. The products described in the examples and comparative examples were prepared into test discs, and their electrochemical performance was tested using an electrochemical workstation. The AC impedance at different response frequencies was recorded, and the different electrode processes with varying reaction time constants were analyzed. The ionic conductivity of the materials was obtained through fitting, analysis, and calculation. The surface lithium carbonate content was measured: the lithium carbonate was dissolved in deionized water, filtered, and the filtrate was neutralized with acid and alkali. Titration was performed using a potentiometric titrator, and the content was calculated based on the amount of titrant consumed. The test results are shown in Table 1.

[0080] Table 1

[0081] project Density (%) Ionic conductivity (S / cm) Surface lithium carbonate content (%) Example 1 98.72 <![CDATA[3.21×10 -4 ]]> 0.012 Example 2 98.61 <![CDATA[3.42×10 -4 ]]> 0.019 Example 3 99.78 <![CDATA[3.61×10 -4 ]]> 0.008 Example 4 98.13 <![CDATA[3.51×10 -4 ]]> 0.011 Example 5 98.25 <![CDATA[3.24×10 -4 ]]> 0.022 Example 6 97.32 <![CDATA[3.06×10 -4 ]]> 0.024 Example 7 96.24 <![CDATA[2.43×10 -4 ]]> 0.140 Example 8 95.23 <![CDATA[2.12×10 -4 ]]> 0.159 Comparative Example 1 90.34 <![CDATA[1.34×10 -4 ]]> 0.470 Comparative Example 2 92.31 <![CDATA[1.72×10 -4 ]]> 0.181

[0082] The test results above show that coating lithium lanthanum zirconium oxide (LLZO) materials with TiCN / W-Cu composite material can significantly improve the stability of LLZO materials, increase their density, reduce the surface lithium carbonate content, and also help improve the ionic conductivity of the material, with ionic conductivity reaching 2×10⁻⁶. -4 S / cm or higher.

[0083] Comparing the test results of Example 3 and Comparative Example 2, it can be found that when the coating material does not contain tungsten, its effect on improving ionic conductivity is significantly weaker.

[0084] Furthermore, comparing the test results of Examples 1-6 with those of Example 7 reveals that when the mass ratio of lithium lanthanum zirconium oxide material to TiCN / W-Cu composite material is 100:(0.1-0.9), the modified lithium lanthanum zirconium oxide material exhibits higher ionic conductivity and is more suitable for use as a solid-state electrolyte in lithium-ion solid-state batteries. Comparing the test results of Examples 1-6 with those of Example 8 reveals that when the mass ratio of TiCN, W, and Cu in the TiCN / W-Cu composite material is (2-3):(76.5-85.5):(13.5-15.5), the modified lithium lanthanum zirconium oxide material demonstrates better overall performance and is more suitable for use as a solid-state electrolyte.

[0085] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A modified lithium lanthanum zirconium oxide material, characterized in that, The material comprises lithium lanthanum zirconium oxide and TiCN / W-Cu composite material, wherein the TiCN / W-Cu composite material is coated on the outer surface of the lithium lanthanum zirconium oxide; the mass ratio of TiCN, W and Cu in the TiCN / W-Cu composite material is (2-3):(76.5-85.5):(13.5-15.5); the TiCN / W-Cu composite material is formed by coating the surface of the lithium lanthanum zirconium oxide with a mixed powder containing copper, tungsten and titanium carbonitride by spark plasma sintering.

2. The modified lithium lanthanum zirconium oxide material of claim 1, wherein, The mass ratio of the lithium lanthanum zirconium oxide material to the TiCN / W-Cu composite material is 100:(0.1-0.9).

3. The modified lithium lanthanum zirconium oxide material of claim 1 or 2, wherein, The molar ratio of Li, La, and Zr elements in the lithium lanthanum zirconium oxide material is (7.0-7.1):3:

2.

4. A method for preparing a modified lithium lanthanum zirconium oxide material according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1, Weigh out lithium source, lanthanum source and zirconium source, and disperse them in a dispersant to obtain a dispersion. Ball mill, dry, sinter and cool the dispersion to obtain lithium lanthanum zirconium oxide material; S2, the lithium lanthanum zirconium oxide material, TiCN, copper-tungsten composite powder, and copper powder are mixed to obtain a mixed powder. The mixed powder is ball-milled and then subjected to spark plasma sintering to obtain the modified lithium lanthanum zirconium oxide material. The copper-tungsten composite powder is copper-coated tungsten composite powder or a mixed powder of copper powder and tungsten powder.

5. The method for preparing the modified lithium lanthanum zirconium oxide material according to claim 4, characterized in that, In step S1, the lithium source includes at least one of lithium carbonate, lithium hydroxide, and lithium nitrate; and / or, the lanthanum source includes at least one of lanthanum oxide, lanthanum hydroxide, and lanthanum nitrate; and / or, the zirconium source includes at least one of zirconium oxide and zirconium hydroxide; and / or, the dispersant includes at least one of anhydrous ethanol and isopropanol, and the solid content of the dispersion is 30%-50%; and / or In S2, the copper-tungsten composite powder is a copper-coated tungsten composite powder, and the molar ratio of tungsten to copper in the copper-coated tungsten composite powder is (2-3):

1.

6. The method for producing a modified lithium lanthanum zirconium oxygen material according to claim 4 or 5, characterized by, In S1, The ball mill rotates at 200-600 rpm, and the milling time is 2-4 hours; and / or The drying temperature is 60-90℃, and the drying time is 4-10 hours; and / or The sintering temperature is 900-1100℃, the sintering time is 10-20h, and the sintering atmosphere is air.

7. The method for preparing the modified lithium lanthanum zirconium oxide material according to claim 4 or 5, characterized in that, In S2, The ball mill rotates at 100-300 rpm, and the milling time is 8-16 hours; and / or The conditions for the spark plasma sintering are: temperature of 1100-1200℃, time of 3-5min, pressure of 30-50MPa, and heating rate of 35-50℃ / s; during the spark plasma sintering process, the powder is placed in a graphite mold and sintered in an inert gas.

8. The application of the modified lithium lanthanum zirconium oxide material according to any one of claims 1 to 3 or the modified lithium lanthanum zirconium oxide material prepared by the preparation method according to any one of claims 4 to 7 in solid electrolytes.

9. Use of the modified lithium lanthanum zirconium oxide material according to any one of claims 1 to 3 or of the modified lithium lanthanum zirconium oxide material produced according to the production process of any one of claims 4 to 7 for the production of lithium-ion solid-state batteries.