A beta-eucryptite aerogel material, and a preparation method and application thereof

Abstract

This invention discloses a β-lithium nepheline aerogel material, its preparation method, and its applications, belonging to the field of nanoporous material preparation technology. This invention uses a simultaneous sol-gel method to prepare β-lithium nepheline aerogel, with lithium chloride as a precursor, ethyl polyacrylate as a dispersant and gel initiator, and propylene oxide as a gel promoter. A composite gel is prepared using an inorganic dispersion sol-gel method, dried with supercritical CO2 to obtain the composite aerogel, and then calcined at high temperature to obtain the β-lithium nepheline aerogel. The prepared β-lithium nepheline aerogel has a density of 0.12–0.39 g / cm³. 3 Its specific surface area can reach 320.1 m². 2 / g. By forming β-nepheline into an aerogel structure, it is endowed with properties such as larger specific surface area, excellent stability, low density and porosity. Through the conductivity of nepheline and the porosity of the aerogel, the interfacial resistance is effectively reduced, the ion exchange rate is improved, and the conductivity of the battery system is enhanced.

Description

Technical Field

[0001] This invention belongs to the field of nanoporous material preparation technology, specifically relating to a β-lithium nepheline aerogel material, its preparation method, and its application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] β-Legion nepheline is a powder material with one-dimensional superionic conductivity, due to its large negative coefficient of thermal expansion (α = -6.1 × 10⁻⁶ K). -1 ), lower density (2.67 g / cm³) 3 Due to its excellent thermal shock resistance, outstanding polarization and chemical stability, dielectric properties, and infrared radiation, β-lithium nepheline is often used as a material to adjust the coefficient of thermal expansion of composite materials. β-lithium nepheline can be combined with other materials to prepare composite materials with negative or near-zero thermal expansion, greatly improving the thermal shock resistance and dimensional stability of the materials, thereby extending their service life. However, due to its high interfacial resistance, its lifespan is relatively short when used as an electrode material. This limits the application of β-lithium nepheline in electrode materials.

[0004] Therefore, finding new methods to reduce the interfacial resistance of β-lithium nepheline to improve its application in the battery field has become an urgent problem to be solved. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a β-lithium nepheline aerogel material, its preparation method, and its application. The present invention increases the specific surface area of ​​β-lithium nepheline by forming it into an aerogel structure, thereby effectively overcoming the disadvantages of β-lithium nepheline as an electrode material.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] In a first aspect, the present invention provides a method for preparing a β-lithium nepheline aerogel material, characterized by comprising the following steps:

[0008] S1: SiO2 sol was prepared using tetraethyl orthosilicate as a precursor; lithium chloride, aluminum chloride and anhydrous ethanol were mixed, polyethyl acrylate was added, and the mixture was stirred to obtain LiO2-Al2O3 composite sol;

[0009] S2: Mix SiO2 sol and LiO2-Al2O3 composite sol, add propylene oxide, stir, and obtain ternary composite sol;

[0010] S3: The ternary composite sol was soaked in anhydrous ethanol for aging and solvent replacement to obtain a ternary composite alcohol gel.

[0011] S4: The ternary composite alcohol gel was subjected to supercritical CO2 drying to obtain a ternary composite aerogel, which was then calcined to obtain β-lithium nepheline aerogel.

[0012] Aerogels are a class of porous materials with large specific surface area and low density. This invention prepares β-lithium nepheline into an aerogel structure, endowing it with excellent properties such as larger specific surface area, superior stability, low density, and high porosity, effectively overcoming the shortcomings of β-lithium nepheline as an electrode material. By incorporating β-lithium nepheline into the aerogel structure, the conductivity of nepheline and the porosity of the aerogel effectively reduce interfacial resistance, significantly improve ion exchange rate, and enhance the conductivity of the battery system, thereby improving battery performance. This invention not only overcomes the limitations of β-lithium nepheline itself but also improves the efficiency of β-lithium nepheline in battery applications.

[0013] In some embodiments of the present invention, in step S1, the method for preparing the SiO2 sol includes the following steps:

[0014] Water and anhydrous ethanol were added to tetraethyl orthosilicate and stirred to obtain SiO2 sol.

[0015] In some embodiments of the present invention, the ratio of tetraethyl orthosilicate, anhydrous ethanol and water is (5-7.5g):(40-50mL):(89-95mL);

[0016] The stirring is carried out for 0.4-0.6 hours at a speed of 300-600 r / min, and the temperature of the solution is 25-50℃ during the stirring process.

[0017] In some embodiments of the present invention, in S1, the molar ratio of lithium chloride, aluminum chloride and anhydrous ethanol is (1-2):(1-2):(7-8).

[0018] In some embodiments of the present invention, in S1, the mixing is a stirring mixture, the stirring time is 5-10 min, the stirring speed is 300-600 r / min; during the stirring process, the temperature of the solution is 25-50℃.

[0019] In some embodiments of the present invention, in S1, the ratio of aluminum chloride to ethyl polyacrylate is (0.1-0.2 mol):(0.25-0.35 g).

[0020] In some embodiments of the present invention, in S1, the stirring time is 0.4-0.6h, the stirring speed is 300-600r / min, and the temperature of the solution is 25-50℃ during the stirring process.

[0021] In some embodiments of the present invention, in S2, the volume ratio of SiO2 sol to LiO2-Al2O3 composite sol is 2.8-3.2:1.

[0022] In some embodiments of the present invention, in S2, the amount of propylene oxide is 5-8 times the mass of tetraethyl orthosilicate.

[0023] In some embodiments of the present invention, in step S2, the stirring time is 5-10 min, the stirring speed is 300-600 r / min, and the temperature of the solution is 25-50℃ during the stirring process.

[0024] In some embodiments of the present invention, in step S3, the soaking time is 6-7 days, during which anhydrous ethanol is replaced every 20-25 hours.

[0025] In some embodiments of the present invention, in S4, the CO2 supercritical drying is performed at a drying pressure of 8-12.5 MPa, a drying temperature of 40-60°C, and a drying time of 1.5-4 h.

[0026] In some embodiments of the present invention, in step S4, the calcination temperature is 800-1300℃ and the calcination time is 1-3h.

[0027] In a second aspect, the present invention provides a β-lithium nepheline aerogel material, wherein the β-lithium nepheline aerogel material is prepared by the preparation method described in the first aspect.

[0028] This invention utilizes a simultaneous sol-gel process to achieve molecular-level mixing of three aerogel components: SiO2, Al2O3, and LiO2. By introducing lithium ions into the silicon-aluminum binary aerogel to form a β-lithium nepheline structure, the aerogel acquires excellent electrical conductivity, further broadening its application range.

[0029] Therefore, in a third aspect, the present invention provides the application of the β-lithium nepheline aerogel material described in the second aspect in a lithium-ion battery;

[0030] The application is that β-lithium nepheline aerogel material is used as an electrode material for lithium-ion batteries.

[0031] In a fourth aspect, the present invention provides a lithium-ion battery, wherein the electrode material of the lithium-ion battery is the β-lithium nepheline aerogel material described in the second aspect.

[0032] The beneficial effects of this invention are as follows:

[0033] This invention utilizes a simultaneous sol-gel method to prepare β-nepheline aerogel. Lithium chloride is used as a precursor, polyethyl acrylate (PAA) as a dispersant and gel initiator, and propylene oxide as a gel promoter. An inorganic dispersion sol-gel method is employed to prepare a Li-Al-Si oxide composite gel. A SiO2-LiO2-Al2O3 composite aerogel is then prepared via supercritical CO2 drying, followed by high-temperature calcination in a muffle furnace to obtain the β-nepheline aerogel. The prepared β-nepheline aerogel has a density of 0.12–0.39 g / cm³. 3 The specific surface area of ​​the calcined β-lithium nepheline aerogel is 68.4–320.1 m². 2 / g. This invention prepares β-lithium nepheline into an aerogel structure, endowing it with excellent properties such as larger specific surface area, superior stability, low density, and high porosity, effectively overcoming the shortcomings of β-lithium nepheline as an electrode material. By incorporating β-lithium nepheline into the aerogel structure, the conductivity of nepheline and the porosity of the aerogel effectively reduce interfacial resistance, significantly improve ion exchange rate, and enhance the conductivity of the battery system, thereby improving battery performance. This invention not only overcomes the limitations of β-lithium nepheline itself but also improves the efficiency of β-lithium nepheline in battery applications. Attached Figure Description

[0034] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0035] Figure 1 This is a physical image of the β-lithium nepheline aerogel material prepared in Example 1 of this invention;

[0036] Figure 2 This is a high-resolution scanning electron microscope image of the β-lithium nepheline aerogel material prepared in Example 2 of the present invention;

[0037] Figure 3 This is the N2 adsorption-desorption curve of the β-lithium nepheline aerogel material prepared in Example 3 of the present invention;

[0038] Figure 4 These are the XRD patterns of the β-lithium nepheline aerogel materials prepared in Examples 1-4 of this invention. Detailed Implementation

[0039] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0040] Example 1

[0041] A method for preparing a β-lithium nepheline aerogel material includes the following steps:

[0042] Add 5.63 g of tetraethyl orthosilicate, 43 mL of anhydrous ethanol, and 90 mL of deionized water to a beaker, seal the container, and stir at 600 r / min for 0.5 h to obtain SiO2 sol (solution ①).

[0043] Add 24.16 g of aluminum chloride hexahydrate, 6.04 g of lithium chloride, and 43 mL of anhydrous ethanol to a beaker, seal the container, and stir at 600 r / min for 5 min. Then add 0.288 g of ethyl polyacrylate, seal the container, and stir at 25 °C and 600 r / min for 0.5 h to obtain LiO2-Al2O3 composite sol (solution ②).

[0044] Solution ② was slowly added to solution ①, and 42 mL of propylene oxide was added to a beaker. After stirring at room temperature for 5 minutes, a ternary composite sol was obtained.

[0045] The ternary composite sol was immersed in anhydrous ethanol for solvent replacement. Fresh anhydrous ethanol was added every 24 hours. The replacement was carried out for about 6 days to completely replace the water in the sol with ethanol, resulting in a ternary composite alcohol gel.

[0046] The ternary composite aerogel was dried in a CO2 supercritical drying apparatus, with the pressure in the drying vessel controlled at 12.5 MPa and the temperature set at 60℃, to obtain SiO2-LiO2-Al2O3 ternary composite aerogel.

[0047] The SiO2-LiO2-Al2O3 ternary composite aerogel was placed in a muffle furnace and calcined at 1300℃ for 1 h to obtain β-lithium nepheline aerogel material.

[0048] The density of the β-lithium nepheline aerogel material prepared in Example 1 was measured to be 0.12 g / cm³. 3 The specific surface area of ​​the calcined β-nepheline aerogel was 68.4 m² / g. XRD analysis confirmed the presence of nepheline structures in the calcined β-nepheline aerogel.

[0049] Figure 1 The image shows the actual β-lithium nepheline aerogel prepared in Example 1, which demonstrates the successful preparation of a block with a three-dimensional structure.

[0050] Example 2

[0051] A method for preparing a β-lithium nepheline aerogel material includes the following steps:

[0052] Add 7.12 g of tetraethyl orthosilicate, 45 mL of anhydrous ethanol, and 94 mL of deionized water to a beaker, seal the container, and stir at 300 r / min for 0.5 h to obtain SiO2 sol (solution ①).

[0053] Add 26.35 g of aluminum chloride hexahydrate, 6.04 g of lithium chloride, and 45 mL of anhydrous ethanol to a beaker, seal the container, and stir at 300 r / min for 5 min. Then add 0.288 g of ethyl polyacrylate, seal the container, and stir at 25 °C and 300 r / min for 0.5 h to obtain LiO2-Al2O3 composite sol (solution ②).

[0054] Solution ② was slowly added to solution ①, and 42 mL of propylene oxide was added to a beaker. After stirring at room temperature for 5 minutes, a ternary composite sol was obtained.

[0055] The ternary composite sol was immersed in anhydrous ethanol for solvent replacement. Fresh anhydrous ethanol was added every 24 hours. The replacement was carried out for about 6 days to completely replace the water in the sol with ethanol, resulting in a ternary composite alcohol gel.

[0056] The ternary composite aerogel was placed in a CO2 supercritical drying apparatus for drying, wherein the pressure of the drying vessel was controlled at 11.5 MPa and the temperature was set at 50℃, to obtain SiO2-LiO2-Al2O3 ternary composite aerogel.

[0057] The SiO2-LiO2-Al2O3 ternary composite aerogel was placed in a muffle furnace and calcined at 800℃ for 2 hours to obtain β-lithium nepheline aerogel material.

[0058] The density of the material prepared in Example 2 was measured to be 0.39 g / cm³. 3 The specific surface area of ​​the calcined β-lithium nepheline aerogel is 320.1 m². 2 / g. XRD analysis revealed the presence of nepheline structures in the calcined β-nepheline aerogel.

[0059] Figure 2 These are high-resolution scanning electron microscope images of the β-lithium nepheline aerogel material prepared in Example 2. (a) is an enlarged image of the β-lithium nepheline aerogel material after calcination, showing that the three materials SiO2-LiO2-Al2O3 are uniformly distributed in the aerogel. (b) is an enlarged image before calcination, showing that the porous nature of the aerogel is clearly visible, and the overall state is a pearl chain-like structure.

[0060] Example 3

[0061] A method for preparing a β-lithium nepheline aerogel material includes the following steps:

[0062] Add 6.12 g of tetraethyl orthosilicate, 43 mL of anhydrous ethanol, and 90 mL of deionized water to a beaker, seal the container, and stir at 400 r / min for 0.5 h to obtain SiO2 sol (solution ①).

[0063] Add 25.12 g of aluminum chloride hexahydrate, 6.78 g of lithium chloride, and 43 mL of anhydrous ethanol to a beaker, seal the container, and stir at 400 r / min for 5 min. Then add 0.302 g of ethyl polyacrylate, seal the container, and stir at 25 °C and 400 r / min for 0.5 h to obtain LiO2-Al2O3 composite sol (solution ②).

[0064] Solution ② was slowly added to solution ①, and 42 mL of propylene oxide was added to a beaker. After stirring at room temperature for 5 minutes, a ternary composite sol was obtained.

[0065] The ternary composite sol was immersed in anhydrous ethanol for solvent replacement. Fresh anhydrous ethanol was added every 24 hours. The replacement was carried out for about 6 days to completely replace the water in the sol with ethanol, resulting in a ternary composite alcohol gel.

[0066] The ternary composite aerogel was placed in a CO2 supercritical drying apparatus for drying, wherein the pressure of the drying vessel was controlled at 10 MPa and the temperature was set at 48℃, to obtain SiO2-LiO2-Al2O3 ternary composite aerogel.

[0067] The SiO2-LiO2-Al2O3 ternary composite aerogel was placed in a muffle furnace and calcined at 1200℃ for 1.5h to obtain β-lithium nepheline aerogel material.

[0068] The material prepared in Example 3 was tested and found to have a density of 0.26 g / cm³. 3 The specific surface area of ​​the calcined β-lithium nepheline aerogel is 270.4 m². 2 / g. XRD analysis revealed the presence of nepheline structures in the calcined β-nepheline aerogel.

[0069] Figure 3 The N2 adsorption-desorption curves of the β-lithium nepheline aerogel material prepared in Example 3 are shown. The hysteresis loop indicates that part of the composite material exhibits the characteristics of a mesoporous material.

[0070] Example 4

[0071] A method for preparing a β-lithium nepheline aerogel material includes the following steps:

[0072] Add 6.04 g of tetraethyl orthosilicate, 43 mL of anhydrous ethanol, and 90 mL of deionized water to a beaker, seal the container, and stir at 400 r / min for 0.5 h to obtain SiO2 sol (solution ①).

[0073] Add 26.28 g of aluminum chloride hexahydrate, 6.04 g of lithium chloride, and 43 mL of anhydrous ethanol to a beaker, seal the container, and stir at 400 r / min for 5 min. Then add 0.312 g of ethyl polyacrylate, seal the container, and stir at 25 °C and 400 r / min for 0.5 h to obtain LiO2-Al2O3 composite sol (solution ②).

[0074] Solution ② was slowly added to solution ①, and 42 mL of propylene oxide was added to a beaker. After stirring at room temperature for 5 minutes, a ternary composite sol was obtained.

[0075] The ternary composite sol was immersed in anhydrous ethanol for solvent replacement. Fresh anhydrous ethanol was added every 24 hours. The replacement was carried out for about 6 days to completely replace the water in the sol with ethanol, resulting in a ternary composite alcohol gel.

[0076] The ternary composite aerogel was placed in a CO2 supercritical drying apparatus for drying, wherein the pressure of the drying vessel was controlled at 12 MPa and the temperature was set at 56℃, to obtain SiO2-LiO2-Al2O3 ternary composite aerogel.

[0077] The SiO2-LiO2-Al2O3 ternary composite aerogel was placed in a muffle furnace and calcined at 1200℃ for 1 h to obtain β-lithium nepheline aerogel material.

[0078] The density of the material prepared in Example 4 was measured to be 0.32 g / cm³. 3 The specific surface area of ​​the calcined β-lithium nepheline aerogel is 297.6 m². 2 / g.

[0079] Figure 4 This is the XRD pattern of the β-nepheline aerogel material prepared in Example 4 of this paper. As can be seen from the figure, the prepared aerogel contains a nepheline structure.

[0080] Material characterization and performance testing

[0081] Electrical performance testing

[0082] In the field of lithium-ion batteries, improving the conductivity and effective surface area of ​​electrode materials is one of the key factors in enhancing battery performance. β-Lithium nepheline exhibits good ionic conductivity, but suffers from high interfacial resistance and poor electron transport. This invention addresses this issue by fabricating β-Lithium nepheline material into an aerogel structure (three-dimensional channel structure). By leveraging the conductivity of lithium nepheline and the porosity of the aerogel, the interfacial resistance is effectively reduced, significantly improving its performance in battery electrodes.

[0083] In standard half-cell tests, the β-lithium nepheline aerogel electrode exhibited lower charge transfer impedance and higher conductivity compared to the conventional β-lithium nepheline powder electrode. Electrochemical testing results showed that the initial coulombic efficiency of the β-lithium nepheline aerogel electrode reached 95%, while the initial coulombic efficiency of the conventional β-lithium nepheline powder electrode was only 90%. Furthermore, the β-lithium nepheline aerogel electrode maintained a higher specific capacity under 1C discharge conditions, with a capacity retention exceeding 90% after 500 cycles, compared to only 80% for the conventional β-lithium nepheline powder electrode.

[0084] The advantages of the β-lithium nepheline aerogel structure prepared in this invention are mainly as follows:

[0085] 1. Increased electronic conduction pathways: The addition of conductive agents and the formation of porous structures enhance the migration ability of electrons in the electrode material, reducing the internal resistance of the electrode.

[0086] 2. Improved lithium-ion diffusion kinetics: The high specific surface area and porous structure provide shorter paths and more active sites for lithium-ion transport, thereby accelerating the lithium-ion diffusion rate.

[0087] 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 method of preparing a β-eucryptite aerogel material, characterized in that, Includes the following steps: S1: SiO2 sol was prepared using tetraethyl orthosilicate as a precursor; lithium chloride, aluminum chloride and anhydrous ethanol were mixed, polyethyl acrylate was added, and the mixture was stirred to obtain LiO2-Al2O3 composite sol; S2: Mix SiO2 sol and LiO2-Al2O3 composite sol, add propylene oxide, stir, and obtain ternary composite sol; S3: The ternary composite sol was soaked in anhydrous ethanol for aging and solvent replacement to obtain a ternary composite alcohol gel. S4: The ternary composite alcohol gel is subjected to supercritical CO2 drying to obtain a ternary composite aerogel, which is then calcined to obtain β-lithium nepheline aerogel; the calcination temperature is 800-1300℃ and the calcination time is 1-3 h.

2. A method of making a β-eucryptite aerogel material according to claim 1, wherein, In S1, the preparation method of the SiO2 sol includes the following steps: Water and anhydrous ethanol were added to tetraethyl orthosilicate and stirred to obtain SiO2 sol.

3. A method of making a β-eucryptite aerogel material according to claim 2, wherein, The ratio of tetraethyl orthosilicate, anhydrous ethanol, and water is (5-7.5 g):(40-50 mL):(89-95 mL).

4. A method of making a β-spodumene aerogel material as claimed in claim 2, characterised in that, The stirring is carried out for 0.4-0.6 hours at a speed of 300-600 r / min, and the temperature of the solution is 25-50℃ during the stirring process.

5. The method of making a β-eucryptite aerogel material of claim 1, wherein, In S1, the molar ratio of lithium chloride, aluminum chloride and anhydrous ethanol is (1-2):(1-2):(7-8); Alternatively, in S1, the mixing is a stirring mixture, with a stirring time of 5-10 min and a stirring speed of 300-600 r / min; during the stirring process, the temperature of the solution is 25-50℃; Alternatively, in S1, the ratio of aluminum chloride to ethyl polyacrylate is (0.1-0.2 mol):(0.25-0.35 g); Alternatively, in S1, the stirring time is 0.4-0.6 h, the stirring speed is 300-600 r / min, and the temperature of the solution is 25-50℃ during the stirring process.

6. The method of making a β-eucryptite aerogel material of claim 1, wherein, In S2, the volume ratio of SiO2 sol to LiO2-Al2O3 composite sol is 2.8-3.2:1; Alternatively, in S2, the amount of propylene oxide used is 5-8 times the mass of tetraethyl orthosilicate; Alternatively, in S2, the stirring time is 5-10 min, the stirring speed is 300-600 r / min, and the temperature of the solution is 25-50℃ during the stirring process.

7. A method of making a β-eucryptite aerogel material as claimed in claim 1, wherein, In S3, the soaking time is 6-7 days, during which the anhydrous ethanol is replaced every 20-25 hours.

8. The method for preparing a β-lithium nepheline aerogel material as described in claim 1, characterized in that, In S4, the CO2 supercritical drying is carried out at a drying pressure of 8-12.5 MPa, a drying temperature of 40-60℃, and a drying time of 1.5-4 h.

9. A β-eucryptite aerogel material characterized by, The β-lithium nepheline aerogel material is prepared by the preparation method according to any one of claims 1-8.

10. The application of the β-lithium nepheline aerogel material according to claim 9 in a lithium-ion battery; The application is that β-lithium nepheline aerogel material is used as an electrode material for lithium-ion batteries.

11. A lithium-ion battery, characterized by The electrode material of the lithium-ion battery is the β-lithium nepheline aerogel material as described in claim 9.

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