A zirconate rare earth-based high-entropy ceramic-silica fiber membrane for lithium / sodium ion battery thermal protection and a preparation method thereof

Abstract

The application discloses a zirconate rare earth-based high-entropy ceramic-silicon dioxide fiber membrane for thermal protection of lithium / sodium ion batteries and a preparation method thereof, and relates to the technical field of high-entropy ceramic nanofiber preparation. Specifically, the zirconate rare earth-based high-entropy ceramic-silicon dioxide fiber membrane precursor is successfully prepared by using an electrostatic spinning technology, and the zirconate rare earth-based high-entropy ceramic-silicon dioxide fiber membrane with flexibility, high-temperature resistance and heat insulation performance is obtained by further processing through a calcination process, so as to provide efficient thermal protection for lithium / sodium ion batteries.

Description

Technical Field

[0001] This invention belongs to the field of high-entropy ceramic nanofiber preparation technology, and relates to a zirconate rare earth-based high-entropy ceramic-silica fiber membrane for thermal protection of lithium / sodium ion batteries and its preparation method. Background Technology

[0002] Lithium / sodium-ion batteries are widely used in portable electronic devices, electric vehicles, and energy storage systems due to their high energy density, long cycle life, and low self-discharge rate. However, with the continuous development of battery technology, the energy density and charge / discharge rate of batteries are constantly increasing, leading to a corresponding increase in the heat generated during battery use. Excessive heat accumulation can cause the battery temperature to rise too high, affecting battery life and even causing safety hazards such as overheating, thermal runaway, fire, or explosion. Therefore, to prevent fires or explosions caused by thermal runaway in lithium batteries, it is necessary to develop high-efficiency ceramic thermal insulation materials with excellent thermal stability and safety.

[0003] Rare earth zirconate-based high-entropy ceramics exhibit superior performance compared to traditional zirconium oxide and silica ceramics due to their unique high-entropy effect, including significantly improved high-temperature resistance, enhanced flexibility, and improved chemical stability. However, the preparation of high-entropy ceramic materials often faces technical challenges such as complex high-temperature sintering processes, high ceramic brittleness, and insufficient material flexibility. These problems limit their application in high-performance thermal insulation materials.

[0004] Therefore, overcoming these challenges and improving the overall performance of high-entropy ceramics, especially their application in the field of thermal protection for lithium / sodium-ion batteries, has become a key focus of current research.

[0005] Based on the above problems, there is a need to provide a high-entropy ceramic material that can exist stably under high temperature conditions, has low thermal conductivity and good flexibility, and can be widely used in the field of thermal protection for lithium / sodium-ion batteries. Summary of the Invention

[0006] To address the problems encountered in the preparation of high-entropy ceramic materials in existing technologies, such as complex high-temperature sintering processes, high brittleness, and insufficient flexibility of the ceramic materials, this invention provides a zirconate-based rare-earth ceramic-silica fiber membrane for thermal protection of lithium / sodium-ion batteries and its preparation method. This method uses electrospinning technology to prepare a precursor for the zirconate-based rare-earth ceramic-silica fiber membrane, and then removes the spinning aid and solvent through a calcination process to finally obtain the zirconate-based rare-earth ceramic-silica fiber membrane. Benefiting from the flexibility of silica and the high-temperature resistance and low thermal conductivity of zirconate-based rare-earth ceramics, the prepared zirconate-based rare-earth ceramic-silica fiber membrane not only possesses excellent thermal insulation performance but also excellent flexibility, enabling its efficient application in the field of thermal protection for lithium / sodium-ion batteries.

[0007] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0008] A zirconate-based rare-earth-based high-entropy ceramic-silica fiber membrane for thermal protection of lithium / sodium-ion batteries and its preparation method are disclosed. The zirconate-based rare-earth-based high-entropy ceramic-silica fiber membrane is composed of a zirconate-based rare-earth-based high-entropy ceramic and silica. The zirconate-based rare-earth-based high-entropy ceramic has the chemical formula Re₂Zr₂O₇ (Re represents rare earth elements such as lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), holmium (Ho), erbium (Er), ytterbium (Yb), lutetium (Lu), scandium (Sc), and yttrium (Y)). A rare-earth-based high-entropy ceramic-silica fiber membrane was synthesized by introducing a silicon source. This membrane exhibits excellent mechanical properties and provides superior thermal insulation, effectively preventing heat transfer from lithium / sodium-ion batteries at high temperatures, thereby significantly improving the safety and thermal stability of lithium / sodium-ion batteries. The preparation process is simple and inexpensive, making it suitable for large-scale industrial production. In particular, the rare-earth-based high-entropy ceramic-silica fiber membrane has broad application prospects as a highly efficient thermal insulation and protection material in lithium / sodium-ion battery thermal protection systems.

[0009] Specifically, a method for preparing a zirconate rare-earth-based high-entropy ceramic-silica fiber membrane for thermal protection of lithium / sodium-ion batteries includes the following steps:

[0010] S1. Dissolve rare earth salt, zirconium salt and silicon source in solvent. The molar ratio of rare earth salt to zirconium salt is 1:1. The ratio of silicon source to zirconium salt is 10wt%-30wt%. Stir evenly to obtain zirconate rare earth-based high entropy ceramic-silica solution.

[0011] The rare earth elements in the rare earth salt are selected from any five of the following: lanthanum (La), cerium (Ce), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), dysprosium (Dy), holmium (Ho), erbium (Er), ytterbium (Yb), thulium (Tm), lutetium (Lu), scandium (Sc), and yttrium (Y), and are proportioned in equimolar stoichiometric ratios.

[0012] The zirconium salt is selected from one of zirconium nitrate, zirconium oxychloride, and zirconium acetate;

[0013] The silicon source is selected from one of the following: tetraethyl orthosilicate (TEOS), tetraethyl orthosilicate (TES), butyl orthosilicate (TBOS), propyl orthosilicate (TPOS), methyl orthosilicate (TMOS), dimethyl orthosilicate (DMMS), and vinyl orthosilicate (VTES).

[0014] The solvent is selected from at least one of water, methanol, ethanol, and N,N-dimethylformamide, and the mixture is in any proportion.

[0015] S2. Add a spinning aid to the obtained rare earth zirconate-based high entropy ceramic-silica solution, with a solvent-to-spinning aid mass ratio of (10-20):1, and stir until uniform to obtain a rare earth zirconate-based high entropy ceramic-silica spinning solution.

[0016] The spinning aid is one of polyvinylpyrrolidone (PVP), polyethylene oxide (PEO), polyvinyl alcohol (PVA), polyacrylonitrile (PAN), or polyvinylidene fluoride (PVDF).

[0017] S3. The obtained zirconate-based high-entropy ceramic-silica spinning solution is used to prepare a wet zirconate-based high-entropy ceramic-silica fiber membrane precursor by electrospinning.

[0018] S4. The obtained wet zirconate rare earth-based high-entropy ceramic-silica fiber membrane precursor is dried to obtain dry zirconate rare earth-based high-entropy ceramic-silica fiber membrane precursor.

[0019] S5. The obtained dry zirconate rare earth-based high-entropy ceramic-silica fiber membrane precursor is calcined to remove the spinning aid and solvent, finally obtaining the zirconate rare earth-based high-entropy ceramic-silica fiber membrane. The typical structural formulas of the zirconate rare earth-based high-entropy ceramic-silica fiber membrane are as follows: (La 0.2 Ce 0.2 Gd 0.2 Er 0.2 Sm 0.2 )2Zr2O7-SiO2、(La 0.2 Gd 0.2 Sm 0.2 Y 0.2 Ho0.2 )2Zr2O7-SiO2 or (Ce 0.2 Sm 0.2 Nd 0.2 Yb 0.2 Gd 0.2 )2Zr2O7-SiO2.

[0020] Furthermore, the rare earth salts mentioned in S1 are selected from rare earth nitrate salts, rare earth chloride salts, rare earth acetate salts, rare earth bromide salts, and rare earth iodide salts.

[0021] Furthermore, the mass ratio of the solvent to the spinning aid described in S1 is preferably 15:1.

[0022] Furthermore, the molar concentration of zirconium in the zirconate rare earth-based high-entropy ceramic-silica solution described in S1 is 0.05 mol / L-0.15 mol / L.

[0023] Furthermore, the spinning aid mentioned in S2 is polyvinylpyrrolidone (PVP).

[0024] Furthermore, the diameter of the dry zirconate rare earth-based high-entropy ceramic-silica fiber membrane precursor described in S4 is between 100nm and 220nm, and it has a uniform fiber diameter distribution.

[0025] Furthermore, the electrospinning process parameters described in S3 are as follows: spinning voltage range of 1kV-30kV, injection speed of 0.05ml / h-1ml / h, spinning receiving distance of 10cm-20cm, spinning humidity of 25%-40%, and spinning temperature controlled at 15℃-30℃.

[0026] Furthermore, the calcination temperature described in S5 is 800℃-1200℃, and typical temperatures can be selected as 800℃, 900℃, 1000℃, 1100℃ and 1200℃; the heating process is as follows: heat to 200℃ at a heating rate of 2℃ / min, hold for 2h, then heat to 600-700℃ at a heating rate of 1-5℃ / min, hold for 2h, and then heat to 900-1200℃ at a heating rate of 1-5℃ / min, hold for 2h.

[0027] This invention also relates to a zirconate rare-earth-based high-entropy ceramic-silica fiber membrane for thermal protection of lithium / sodium-ion batteries. It is obtained using the aforementioned method for preparing the zirconate rare-earth-based high-entropy ceramic-silica fiber membrane. A spinning solution for the zirconate rare-earth-based high-entropy ceramic-silica fiber membrane is obtained by mixing a solvent, spinning aid, rare-earth salt, zirconium salt, and silicon source. The membrane is then obtained through electrospinning and calcination. The chemical formula of the zirconate rare-earth-based high-entropy ceramic is Re₂Zr₂O₇, where Re is selected from five rare-earth elements: lanthanum (La), cerium (Ce), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), dysprosium (Dy), holmium (Ho), erbium (Er), ytterbium (Yb), thulium (Tm), lutetium (Lu), scandium (Sc), and yttrium (Y). Typical structural formulas include the following chemical formulas: (La...) 0.2 Ce 0.2 Gd 0.2 Er 0.2 Sm 0.2 )2Zr2O7-SiO2、(La 0.2 Gd 0.2 Sm 0.2 Y 0.2 Ho 0.2 )2Zr2O7-SiO2 or (Ce 0.2 Sm 0.2 Nd 0.2 Yb 0.2 Gd 0.2 The process involves a zirconate-based high-entropy ceramic (Zr₂O₇-SiO₂) structure where rare-earth zirconate-based high-entropy ceramics are uniformly distributed in the form of nanoparticles within silica fibers. In this zirconate-based high-entropy ceramic-silica fiber membrane for thermal protection of lithium / sodium-ion batteries, the mass percentage of silica is 10%-30%, and the mass percentage of the rare-earth zirconate-based high-entropy ceramics is 70%-90%. This membrane possesses the following technical specifications: a thermal conductivity of 0.05 W / m·K, which is 86% lower than the 0.093 W / m·K of pure silica fiber membrane.

[0028] Furthermore, compared to zirconia fiber membranes, the zirconate rare earth-based high-entropy ceramic-silica fiber membrane for thermal protection of lithium / sodium-ion batteries maintains good flexibility after 45 cycles under 8% strain. With the protection of this zirconate rare earth-based high-entropy ceramic-silica fiber membrane for thermal protection of lithium / sodium-ion batteries, the risk of secondary explosion of lithium / sodium-ion batteries under overheating conditions can be prevented.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. This invention discloses a method for preparing a rare-earth-based high-entropy ceramic-silica fiber membrane for thermal protection of lithium / sodium-ion batteries. The method employs electrospinning technology and a calcination process to prepare the rare-earth-based high-entropy ceramic-silica fiber membrane. The rare-earth-based high-entropy ceramic is embedded in silica fibers in the form of nanoparticles. The synergistic effect between the rare-earth-based high-entropy ceramic and silica not only preserves the flexibility of the silica fibers but also significantly improves the high-temperature resistance of the rare-earth-based high-entropy ceramic through the high-entropy effect. Compared with existing technologies, the method of this invention is simple, easy to operate, and suitable for industrial production. Among them, the thermal conductivity of the rare earth zirconate-based high-entropy ceramic-silica fiber membrane is 0.05 W / m·K, which is about 46% lower than that of the pure silica fiber membrane (0.093 W / m·K). It can withstand a high temperature of 1200℃, which is 150% higher than that of traditional silica fiber (temperature resistance of 800℃). Under 8% strain, after 45 cycles, the rare earth zirconate-based high-entropy ceramic-silica fiber membrane still maintains good flexibility. In addition, the rare earth zirconate-based high-entropy ceramic-silica fiber membrane can effectively isolate the potential risks of lithium / sodium-ion battery protection systems. With the protection of this fiber membrane, the risk of secondary explosion of lithium / sodium-ion batteries under thermal runaway environment is eliminated.

[0031] 2. The present invention discloses a method for preparing a zirconate-based rare-earth-based high-entropy ceramic-silica fiber membrane for thermal protection of lithium / sodium-ion batteries. The prepared zirconate-based rare-earth-based high-entropy ceramic-silica fiber membrane combines the excellent high-temperature resistance of zirconate-based high-entropy ceramics with the flexibility of silica fibers, successfully overcoming the drawback of high-entropy ceramics' brittleness and significantly improving the mechanical properties and thermal stability of the fiber membrane. This zirconate-based rare-earth-based high-entropy ceramic-silica fiber membrane has broad application prospects in the field of thermal protection for lithium / sodium-ion batteries, especially in effectively mitigating the thermal runaway process of lithium / sodium-ion batteries under extreme conditions such as overcharging, over-discharging, and external short circuits, thereby providing additional safety protection for lithium / sodium-ion batteries.

[0032] 3. The present invention describes a method for preparing a rare earth zirconate-based high entropy ceramic-silica fiber membrane for thermal protection of lithium / sodium-ion batteries. The method employs electrospinning technology to prepare a precursor for the rare earth zirconate-based high entropy ceramic-silica fiber membrane, and then obtains the membrane with flexibility, high temperature resistance, and thermal insulation properties through a calcination process. This method aims to provide efficient thermal protection for lithium / sodium-ion batteries. Attached Figure Description

[0033] Figure 1 This is a scanning electron microscope image of the zirconate rare earth-based high-entropy ceramic-silica fiber precursor in Example 1 of the present invention;

[0034] Figure 2 This is a scanning electron microscope image of the rare earth zirconate-based high-entropy ceramic-silica fiber in Example 2 of the present invention;

[0035] Figure 3 This is a transmission electron microscope image of zirconate rare earth-based high-entropy ceramic-silica fiber in Example 3 of the present invention;

[0036] Figure 4 This is a transmission electron microscope image of zirconate rare earth-based high-entropy ceramic-silica fiber in Example 3 of the present invention;

[0037] Figure 5 The energy dispersive X-ray spectrum of the rare earth zirconate-based high-entropy ceramic-silica fiber in Example 1 of this invention is shown below.

[0038] Figure 6 This is the X-ray diffraction pattern of the rare earth zirconate-based high-entropy ceramic-silica fiber in Example 1 of the present invention;

[0039] Figure 7 Thermogravimetric curve of the zirconate rare earth-based high-entropy ceramic-silica fiber membrane precursor in Example 1 of the present invention;

[0040] Figure 8 This is a photograph of the zirconate rare earth-based high-entropy ceramic-silica fiber membrane in Example 1 of the present invention;

[0041] Figure 9 This is a stress-strain curve of the zirconate rare earth-based high-entropy ceramic-silica fiber membrane in Example 2 of the present invention;

[0042] Figure 10 This is a schematic diagram of the lithium / sodium ion battery before the thermal protection experiment in Example 1 of the present invention;

[0043] Figure 11 This is an example diagram showing the thermal protection test results of a lithium / sodium ion battery in Example 1 of the present invention;

[0044] Figure 12 This is a schematic diagram of the lithium / sodium ion battery after thermal protection, using a zirconate rare earth-based high-entropy ceramic-silica fiber membrane and an unprotected lithium / sodium ion battery in Example 1 of the present invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of this invention and should not be construed as limiting the scope of protection of this invention. All technologies implemented based on the above content of this invention are covered within the scope of protection intended by this invention.

[0046] In summary, this invention prepares a rare-earth-based high-entropy ceramic-silica fiber membrane using electrospinning and calcination techniques. During fiber formation, the rare-earth-based high-entropy ceramic is embedded within the silica fibers in the form of nanoparticles. The synergistic effect between the rare-earth-based high-entropy ceramic and silica allows the rare-earth-based high-entropy ceramic-silica fiber membrane to retain the flexibility of silica fibers while significantly improving the high-temperature resistance of the rare-earth-based high-entropy ceramic through the high-entropy effect.

[0047] Example 1:

[0048] A method for preparing a rare-earth zirconate-based high-entropy ceramic-silica fiber membrane for thermal protection of lithium / sodium-ion batteries includes the following steps:

[0049] (1) Add 0.5g of five equimolar ratios of La, Ce, Gd, Er, and Sm, 0.5g of Zr element, and 1ml of tetraethyl orthosilicate (TEOS) to 10ml of ethanol, 5ml of deionized water, and 2ml of N,N-dimethylformamide (DMF). Add 0.05ml of nitric acid and adjust the pH of the solution to 6.

[0050] (2) Add 2g of polyvinylpyrrolidone (molecular weight 1.3 million) to the zirconate rare earth-based high entropy ceramic-silica solution obtained in step (1) and stir at 1000 rpm and 30°C for 5h on a magnetic stirrer.

[0051] (3) Add the zirconate rare earth-based high entropy ceramic-silica solution obtained in step (2) into a 10ml syringe with a needle inner diameter of 23mm, a syringe advance speed of 0.2ml / h, a spinning voltage of 22kV, a needle-to-roll collecting distance of 20cm, a roll rotation speed of 200rpm, a spinning temperature of 25℃, and a spinning humidity of 30%.

[0052] (4) The wet zirconate rare earth-based high-entropy ceramic-silica fiber membrane precursor obtained in step (3) was placed in an oven at 80°C and dried for 10 hours. The dried zirconate rare earth-based high-entropy ceramic-silica fiber membrane precursor was then placed in a muffle furnace for calcination. The temperature was increased to 200°C at 2°C / min and held for 2 hours. The temperature was then increased to 650°C at 2°C / min and held for 2 hours. The temperature was then increased to 1000°C at 2°C / min and held for 2 hours to obtain the zirconate rare earth-based high-entropy ceramic-silica fiber membrane ((La 0.2 Ce 0.2 Gd 0.2 Er 0.2 Sm 0.2 )2Zr2O7-SiO2).

[0053] Example 2:

[0054] Compared to Example 1, most aspects are the same, the difference being that the elements in the raw materials of step (1) are adjusted to Dy, Ho, Er, Tm, and Yb. After the same operation as in Example 1, (Dy 0.2 Ho 0.2 Er 0.2 Tm 0.2 Yb 0.2 )2Zr2O7-SiO2 fiber membrane.

[0055] Example 3:

[0056] Compared to Example 1, most aspects are the same, except that the elements in the raw materials of step (1) are adjusted to La, Ce, Pr, Nd, and Pm. After the same operation as in Example 1, (La) is obtained. 0.2 Ce 0.2 Pr 0.2 Nd 0.2 Pm 0.2 )2Zr2O7-SiO2 fiber membrane.

[0057] Example 4:

[0058] Compared with Example 1, most of the contents are the same, except that the addition of 1 ml of tetraethyl orthosilicate in step (1) is replaced with 0.5 ml of tetraethyl orthosilicate.

[0059] Example 5:

[0060] Compared with Example 1, most of the contents are the same, except that the tetraethyl orthosilicate (TEOS) in step (1) is replaced with tetraethyl orthosilicate (TES).

[0061] Example 6:

[0062] The majority of the steps are the same as in Example 1, except that the nitric acid in step (1) is replaced with sulfuric acid.

[0063] Example 7:

[0064] Compared with Example 1, most of the steps are the same, except that the addition of 2g of polyvinylpyrrolidone (PVP) in step (2) is replaced with the addition of 1g of polyvinylpyrrolidone.

[0065] Example 8:

[0066] The two methods are largely the same as in Example 1, except that polyvinylpyrrolidone (PVP) in step (2) is replaced with polyethylene oxide (PEO).

[0067] Example 9:

[0068] Compared with Example 1, most of the results are the same, except that the syringe injection speed in step (3) is changed to 0.5 ml / h.

[0069] Example 10:

[0070] Compared with Example 1, most of the results are the same, except that the spinning voltage in step (3) is changed to 10kV.

[0071] Example 11:

[0072] The majority of the steps are the same as in Example 1, except that the heating rate in step (4) is changed to 1°C / min.

[0073] Example 12:

[0074] Compared with Example 1, most of the results are the same, except that the temperature in step (4) is changed from 1000°C to 900°C.

[0075] Example 13:

[0076] Compared with Example 1, most of the contents are the same, except that the drum speed in step (4) is changed from 200 rpm to 400 rpm.

[0077] Comparative Example 1:

[0078] (1) Add 2g of five elements in equimolar ratios of La, Ce, Gd, Er, and Sm, and 2g of Zr to 10ml of ethanol, 5ml of deionized water, and 2ml of N,N-dimethylformamide (DMF);

[0079] (2) Add 2g of polyvinylpyrrolidone (molecular weight 1.3 million, PVP) to the zirconate rare earth-based high entropy ceramic solution obtained in step (1) and stir at 1000rpm and 30℃ for 5h on a magnetic stirrer.

[0080] (3) Add the zirconate rare earth-based high-entropy ceramic spinning solution obtained in step (2) into a 10 ml syringe with a needle inner diameter of 23 mm, a syringe advance speed of 0.2 ml / h, a spinning voltage of 22 kV, a needle-to-roll collecting distance of 20 cm, a roll rotation speed of 200 rpm, a spinning temperature of 25 °C, and a spinning humidity of 30%.

[0081] (4) The wet zirconate rare earth-based high-entropy ceramic fiber membrane precursor obtained in step (3) is placed in an oven at 80°C and dried for 10 hours. The dried zirconate rare earth-based high-entropy ceramic fiber membrane precursor is placed in a muffle furnace for calcination. The temperature is increased to 200°C at 2°C / min and held for 2 hours. The temperature is increased to 650°C at 2°C / min and held for 2 hours. The temperature is increased to 1000°C at 2°C / min and held for 2 hours to obtain the zirconate rare earth-based high-entropy ceramic fiber membrane.

[0082] Comparative Example 2:

[0083] (1) Add 1 ml of tetraethyl orthosilicate (TEOS) to 10 ml of ethanol, 5 ml of deionized water and 2 ml of N,N-dimethylformamide (DMF), add 0.05 ml of nitric acid and adjust the pH of the solution to 6;

[0084] (2) Add 2g of polyvinylpyrrolidone (molecular weight 1.3 million, PVP) to the silica solution obtained in step (1) and stir at 1000rpm and 30℃ for 5h on a magnetic stirrer.

[0085] (3) Add the silica spinning solution obtained in step (2) into a 10ml syringe with a needle inner diameter of 23mm, a syringe advance speed of 0.2ml / h, a spinning voltage of 22kV, a needle-to-roll collecting distance of 20cm, a roll rotation speed of 200rpm, a spinning temperature of 25℃, and a spinning humidity of 30%.

[0086] (4) The wet silica fiber membrane precursor obtained in step (3) is placed in an oven at 80°C and dried for 10 hours. The dried silica fiber membrane precursor is then placed in a muffle furnace for calcination. The temperature is increased to 800°C at 2°C / min and held for 2 hours to obtain the silica fiber membrane.

[0087] Comparative Example 3:

[0088] (1) Add 2g of zirconium nitrate to 10ml of ethanol, 5ml of deionized water and 2ml of N,N-dimethylformamide (DMF);

[0089] (2) Add 2g of polyvinylpyrrolidone (molecular weight 1.3 million, PVP) to the zirconium oxide solution obtained in step (1) and stir at 1000rpm and 30℃ for 5h on a magnetic stirrer.

[0090] (3) Add the zirconium oxide spinning solution obtained in step (2) into a 10 ml syringe with a needle inner diameter of 23 mm, a syringe advance speed of 0.2 ml / h, a spinning voltage of 22 kV, a needle-to-roll collecting distance of 20 cm, a roll rotation speed of 200 rpm, a spinning temperature of 25 °C, and a spinning humidity of 30%.

[0091] (4) The wet zirconia fiber membrane precursor obtained in step (3) is placed in an oven at 80°C and dried for 10 hours. The dried zirconia fiber membrane precursor is placed in a muffle furnace for calcination. The temperature is increased to 200°C at 2°C / min and held for 2 hours. The temperature is increased to 650°C at 2°C / min and held for 2 hours. The temperature is increased to 1000°C at 2°C / min and held for 2 hours to obtain a zirconia ceramic fiber membrane.

[0092] Results and Discussion:

[0093] 1. The zirconate rare earth-based high-entropy ceramic-silica fiber membranes prepared in the examples were subjected to the following processes:

[0094] Scanning electron microscopy (SEM) characterization (see results for:) Figure 1 This is a scanning electron microscope image of the zirconate rare earth-based high-entropy ceramic-silica fiber precursor in Example 1; Figure 2 (Scanning electron microscope image of rare earth zirconate-based high-entropy ceramic-silica fiber in Example 2);

[0095] Transmission electron microscopy (TEM) characterization (see results: Figure 3 This is a transmission electron microscope image of the rare earth zirconate-based high-entropy ceramic-silica fiber in Example 3; Figure 4 This is a transmission electron microscope image of the rare earth zirconate-based high-entropy ceramic-silica fiber in Example 3; Figure 5 (Energy dispersive X-ray spectrum of zirconate rare earth-based high-entropy ceramic-silica fiber in Example 1);

[0096] X-ray diffraction (XRD) test results (see: Figure 6 (X-ray diffraction pattern of zirconate rare earth-based high-entropy ceramic-silica fiber in Example 1);

[0097] Thermogravimetric analysis (TG) (Results can be found in: Figure 7 Thermogravimetric curve of the zirconate rare earth-based high-entropy ceramic-silica fiber precursor in Example 1).

[0098] The results show that the synthesized rare earth zirconate-based high entropy ceramic-silica fibers have a uniform diameter, and the rare earth zirconate-based high entropy ceramics are uniformly dispersed in the silica fibers in the form of nanoparticles.

[0099] 2. The zirconate rare earth-based high-entropy ceramic-silica fiber membrane prepared in the examples was subjected to the following tests:

[0100] Flexibility test (see schematic diagram): Figure 8 (A physical image of the zirconate rare earth-based high-entropy ceramic-silica fiber membrane in Example 1);

[0101] Stress-strain test (results can be found in:) Figure 9 (This is a stress-strain curve of the zirconate rare earth-based high-entropy ceramic-silica fiber membrane in Example 2);

[0102] Thermal protection performance of zirconate rare-earth-based high-entropy ceramic-silica fiber membranes for lithium / sodium-ion batteries under thermal runaway conditions (see results: Figure 10 This is a schematic diagram of the lithium / sodium ion battery before the thermal protection experiment in Example 1; Figure 11 This is an example diagram showing the results of the thermal protection test of the lithium / sodium ion battery in Example 1; Figure 12 This is a schematic diagram of the lithium / sodium ion battery after thermal protection, comparing the zirconate rare earth-based high-entropy ceramic-silica fiber membrane with and without membrane protection in Example 1.

[0103] The results show that the zirconate rare earth-based high-entropy ceramic-silica fiber membrane not only has excellent flexibility, but also effectively provides thermal protection for lithium / sodium ion batteries.

[0104] 3. In summary, based on the method of this invention, by adjusting the types of rare earth elements, silicon source content, spinning speed, voltage, calcination temperature, heating rate, and time through electrospinning technology, a zirconate rare earth-based high-entropy ceramic-silica composite fiber membrane for thermal protection of lithium / sodium-ion batteries was prepared. The specific composition of the fiber membrane includes zirconate rare earth-based high-entropy ceramic particles and silica fibers, wherein (La... 0.2 Ce 0.2 Gd 0.2 Er 0.2 Sm 0.2 The Zr₂O₇-SiO₂ fiber membrane (Example 1) maintained its structural integrity after heating at 1000°C for 2 hours, while the zirconate rare earth-based high-entropy ceramic fiber membrane (Comparative Example 1) showed significant cracking; (La 0.2 Ce 0.2 Gd 0.2 Er 0.2 Sm 0.2 The thermal conductivity of the 2Zr₂O₇-SiO₂ fiber membrane is 0.05 W / m·K, which is 86% lower than that of the pure silica fiber membrane (0.093 W / m·K, Comparative Example 2). Compared with the zirconium oxide fiber membrane (Comparative Example 3), under 8% strain, (La) 0.2 Ce 0.2 Gd 0.2 Er 0.2 Sm 0.2 The 2Zr2O7-SiO2 fiber membrane maintained good flexibility after 45 cycles. The protection provided by this rare-earth zirconate-based high-entropy ceramic-silica fiber membrane can prevent the risk of secondary explosions in lithium / sodium-ion batteries under overheating conditions.

[0105] The zirconate-based high-entropy ceramic-silica fiber membrane of the present invention combines the excellent high-temperature resistance of zirconate-based high-entropy ceramics with the flexibility of silica fibers, overcoming the brittleness of high-entropy ceramic materials and significantly improving the mechanical properties and thermal stability of the material. This fiber membrane has significant thermal protection performance and can effectively mitigate the thermal runaway process under extreme conditions such as overcharging, over-discharging and external short circuits of lithium / sodium ion batteries, thereby providing additional safety protection for lithium / sodium ion batteries.

[0106] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements 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 for preparing a zirconate rare-earth-based high-entropy ceramic-silica fiber membrane for thermal protection of lithium / sodium-ion batteries, characterized in that: Includes the following steps: S1. Dissolve rare earth salt, zirconium salt and silicon source in solvent. The molar ratio of rare earth salt to zirconium salt is 1:

1. The ratio of silicon source to zirconium salt is 10wt%-30wt%. Stir evenly to obtain zirconate rare earth-based high entropy ceramic-silica solution, wherein the molar concentration of zirconium element is 0.05mol / L-0.15mol / L. The rare earth salts are selected from rare earth nitrate salts, rare earth chloride salts, rare earth acetate salts, rare earth bromide salts, and rare earth iodide salts; the rare earth elements in the rare earth salts are selected from any five of lanthanum, cerium, neodymium, samarium, europium, gadolinium, dysprosium, holmium, erbium, ytterbium, thulium, lutetium, scandium, and yttrium, and are proportioned in equimolar stoichiometric ratios. The zirconium salt is selected from one of zirconium nitrate, zirconium oxychloride, and zirconium acetate; The silicon source is selected from one of tetraethyl orthosilicate, tetraethyl orthosilicate, butyl orthosilicate, propyl orthosilicate, methyl orthosilicate, dimethyl orthosilicate, and vinyl orthosilicate. The solvent is selected from at least one of water, methanol, ethanol, and N,N-dimethylformamide, and the mixture is in any proportion. S2. Add a spinning aid to the obtained rare earth zirconate-based high entropy ceramic-silica solution, with a solvent-to-spinning aid mass ratio of (10-20):1, and stir until uniform to obtain a rare earth zirconate-based high entropy ceramic-silica spinning solution. The spinning aid is one of polyvinylpyrrolidone, polyethylene oxide, polyvinyl alcohol, polyacrylonitrile, or polyvinylidene fluoride; S3. The obtained zirconate-based high-entropy ceramic-silica spinning solution is used to prepare a wet zirconate-based high-entropy ceramic-silica fiber membrane precursor by electrospinning. S4. The obtained wet rare earth zirconate-based high entropy ceramic-silica fiber membrane precursor is dried to obtain a dry rare earth zirconate-based high entropy ceramic-silica fiber membrane precursor; the diameter of the dry rare earth zirconate-based high entropy ceramic-silica fiber membrane precursor is between 100nm and 220nm, and it has a uniform fiber diameter distribution. S5. The obtained dry zirconate rare earth-based high-entropy ceramic-silica fiber membrane precursor is calcined to remove the spinning aid and solvent, finally obtaining the zirconate rare earth-based high-entropy ceramic-silica fiber membrane. The typical structural formulas of the zirconate rare earth-based high-entropy ceramic-silica fiber membrane are as follows: (La 0.2 Ce 0.2 Gd 0.2 Er 0.2 Sm 0.2 )2Zr2O7-SiO2、(Dy 0.2 Ho 0.2 Er 0.2 Tm 0.2 Yb 0.2 )2Zr2O7-SiO2 or (La 0.2 Ce 0.2 Pr 0.2 Nd 0.2 Pm 0.2 )2Zr2O7-SiO2.

2. The method for preparing a zirconate rare earth-based high-entropy ceramic-silica fiber membrane for thermal protection of lithium / sodium-ion batteries according to claim 1, characterized in that: The mass ratio of the solvent to the spinning aid described in S1 is 15:

1.

3. The method for preparing a zirconate rare earth-based high-entropy ceramic-silica fiber membrane for thermal protection of lithium / sodium-ion batteries according to claim 1, characterized in that: The spinning aid mentioned in S2 is polyvinylpyrrolidone.

4. The method for preparing a zirconate rare earth-based high-entropy ceramic-silica fiber membrane for thermal protection of lithium / sodium-ion batteries according to claim 1, characterized in that: The electrospinning process parameters described in S3 are as follows: spinning voltage range of 1kV-30kV, injection speed of 0.05ml / h-1ml / h, spinning receiving distance of 10cm-20cm, spinning humidity of 25%-40%, and spinning temperature controlled at 15℃-30℃.

5. The method for preparing a zirconate rare earth-based high-entropy ceramic-silica fiber membrane for thermal protection of lithium / sodium-ion batteries according to claim 1, characterized in that: The calcination temperature described in S5 is 800℃-1200℃, and typical temperatures can be selected as 800℃, 900℃, 1000℃, 1100℃ and 1200℃; the heating process is as follows: heat to 200℃ at a heating rate of 2℃ / min, hold for 2h, then heat to 600-700℃ at a heating rate of 1-5℃ / min, hold for 2h, then heat to 900℃-1200℃ at a heating rate of 1℃ / min-5℃ / min, hold for 2h.

6. A zirconate rare-earth-based high-entropy ceramic-silica fiber membrane for thermal protection of lithium / sodium-ion batteries, characterized in that: The zirconate-based rare earth ceramic-silica fiber membrane for thermal protection of lithium / sodium-ion batteries, as described in any one of claims 1-5, and its preparation method thereof, wherein the chemical formula of the zirconate-based rare earth ceramic is Re₂Zr₂O₇, wherein Re is selected from five rare earth elements: lanthanum, cerium, neodymium, samarium, europium, gadolinium, dysprosium, holmium, erbium, ytterbium, thulium, lutetium, scandium, and yttrium. Typical structural formulas include the following chemical formulas: (La 0.2 Ce 0.2 Gd 0.2 Er 0.2 Sm 0.2 )2Zr2O7-SiO2、(La 0.2 Gd 0.2 Sm 0.2 Y 0.2 Ho 0.2 )2Zr2O7-SiO2 or (Ce 0.2 Sm 0.2 Nd 0.2 Yb 0.2 Gd 0.2 The process involves a Zr₂O₇-SiO₂ membrane, in which rare earth zirconate-based high-entropy ceramics are uniformly distributed in the form of nanoparticles within silica fibers. The silica content of the rare earth zirconate-based high-entropy ceramic-silica fiber membrane is 10%-30% by mass, and the content of the rare earth zirconate-based high-entropy ceramics is 70%-90% by mass. The rare earth zirconate-based high-entropy ceramic-silica fiber membrane possesses the following technical specifications: thermal conductivity of 0.05 W / m·K; and the ability to maintain good flexibility after 45 cycles under 8% strain.

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