A symbiotic structure lithium ion sieve membrane, a preparation method thereof and application thereof in seawater lithium extraction

Abstract

This invention discloses a symbiotic lithium-ion sieve membrane, its preparation method, and its application in seawater lithium extraction. The symbiotic lithium-ion sieve membrane comprises an inorganic lithium-ion sieve membrane and a symbiotic structural layer grown on its surface. The symbiotic structural layer includes a protective layer and a lattice-matched interface phase formed between the protective layer and the inorganic lithium-ion sieve membrane. This interface phase is formed by the protective layer's main material penetrating into the inorganic lithium-ion sieve membrane and then being reconstructed. The preparation method involves spin-coating a symbiotic structural layer precursor sol onto the polished surface of the inorganic lithium-ion sieve membrane, followed by sintering to allow the precursor material to penetrate and grow. This spin-coating-sintering process is repeated until a completely covering symbiotic structural layer is formed. The symbiotic lithium-ion sieve membrane prepared by this invention maintains continuous Li... + While providing a transmission channel, it can effectively block the chemical corrosion of inorganic lithium-ion screen membranes by seawater, greatly improving their operational stability and making them stable for use in the lithium extraction process from seawater or brine.

Description

Technical Field

[0001] This invention belongs to the field of seawater lithium extraction technology, specifically relating to a symbiotic lithium-ion sieve membrane, its preparation method, and its application in seawater lithium extraction. Background Technology

[0002] Against the backdrop of the rapid development of the global new energy industry, lithium, as a core resource in fields such as power batteries and energy storage systems, is becoming increasingly important. However, terrestrial lithium resources are unevenly distributed and limited in reserves, making it difficult to meet the continuously growing demand in the future. In contrast, the total lithium resources contained in seawater amount to 230 billion tons, thousands of times that of terrestrial lithium resources. Therefore, developing efficient seawater lithium extraction technology is of irreplaceable importance for ensuring the security of the lithium supply chain and broadening the channels for lithium resource acquisition. Currently, there are various seawater lithium extraction technology routes, among which seawater lithium extraction technology based on combined electrolytes has become a research hotspot due to its unique advantages. This technology uses a solid lithium-ion sieve membrane capable of selectively transporting lithium ions as the core component. The dense crystalline structure of the membrane achieves physical isolation between seawater and the recycled electrolyte, while providing a dedicated transport channel for lithium ions. This design endows the technology with excellent lithium-ion selectivity, high separation efficiency, and a relatively simple operating process. In particular, when an organic system is used for the recycled electrolyte, metallic lithium can be directly prepared from seawater through a one-step electrolysis method, thereby greatly simplifying the lithium extraction process and showing good application prospects. However, solid lithium-ion membranes face a fatal flaw in actual seawater lithium extraction processes. Seawater is rich in Na... + Mg 2+ Other cations, such as lithium ions, can undergo ion exchange reactions with lithium ions in the crystal structure of lithium-ion sieve membranes. This exchange reaction leads to the dissolution of membrane microparticles and damage to the crystal structure. Continuous chemical corrosion gradually reduces the ionic conductivity and lithium-ion selectivity of the membrane, ultimately causing membrane failure and failing to meet the engineering requirements for long-term stable lithium extraction. To address this issue, existing technologies have attempted to improve the stability of solid electrolytes by constructing protective coatings on the surface. For example, some studies have used atomic layer deposition (ALD) or molecular layer deposition (MLD) methods to prepare nanoscale protective coatings on the surface of solid electrolytes to reduce chemical corrosion and improve operational stability. However, these methods have significant drawbacks: ALD and MLD processes are complex and require sophisticated equipment; the deposited film forms a new interface with the solid electrolyte substrate, increasing the resistance to ion transport and affecting the overall conductivity. Furthermore, these methods require expensive supporting equipment, which is not conducive to large-scale production and practical applications. Therefore, there is an urgent need to develop a lithium-ion sieve membrane modification scheme that can effectively resist seawater corrosion without introducing additional interfacial resistance and with a simple and controllable process to meet the needs of the industrialization of seawater lithium extraction technology. Summary of the Invention

[0003] Technical problem solved: This invention provides a symbiotic structure lithium-ion sieve membrane, its preparation method, and its application in seawater lithium extraction. The method is simple, and the prepared symbiotic structure lithium-ion sieve membrane exhibits continuous Li₂... + The transmission channel maintains good lithium-ion selectivity and resists continuous chemical corrosion from seawater, enabling stable lithium extraction over a long period of time and avoiding the risks of microparticle dissolution and membrane structure damage in lithium-ion screening membranes.

[0004] Technical solution: A symbiotic lithium-ion sieve membrane, comprising: an inorganic lithium-ion sieve membrane; and a symbiotic structure layer, wherein the symbiotic structure layer is grown on the surface of the inorganic lithium-ion sieve membrane; wherein the symbiotic structure layer includes a protective layer and a lattice-matching interface phase located between the protective layer and the inorganic lithium-ion sieve membrane, the lattice-matching interface phase being formed by the main material of the protective layer penetrating into the inorganic lithium-ion sieve membrane and then being reconstructed.

[0005] The inorganic lithium-ion sieve membrane described above is composed of an inorganic solid electrolyte; the inorganic solid electrolyte is selected from any one of NASICON structure oxides, perovskite structure oxides, or garnet structure oxides.

[0006] The above-mentioned NASICON structure oxide is Li 1+x Al x Ge 2-x (PO4)3 and Li 1+x Al x Ti 2-x (PO4)3, 0.2≤x≤0.8; the garnet-structured oxide is Li 7-y La3Zr 2-y Ta y O 12 , 0≤y≤1; the perovskite structure oxide is Li 3z La 2 / 3-z TiO3, 0 < z ≤ 2 / 3.

[0007] The main material of the aforementioned protective layer is capable of transporting Li. + TiO2.

[0008] The method for preparing the above-mentioned symbiotic structure lithium-ion screen membrane includes the following steps: S1. Preparing an inorganic solid lithium-ion screen membrane; S2. Preparing a precursor sol for the symbiotic structure layer; S3. Polishing the surface of the inorganic solid lithium-ion screen membrane prepared in step S1; S4. Spin-coating the precursor sol prepared in step S2 onto the polished surface of the inorganic solid lithium-ion screen membrane prepared in step S3; S5. Sintering the inorganic solid lithium-ion screen membrane prepared in step S4; S6. Repeating steps S4 and S5 at least once until the symbiotic structure layer completely covers the surface of the inorganic solid lithium-ion screen membrane, thereby obtaining the symbiotic structure lithium-ion screen membrane.

[0009] The method for preparing inorganic solid lithium-ion screen membrane in step S1 above includes: weighing raw materials according to the chemical ratio of the target inorganic solid lithium-ion screen membrane, ball milling, heat treatment, ball milling again, and sintering to obtain inorganic solid lithium-ion screen membrane powder; pressing the powder into a green blank and sintering it to obtain inorganic solid lithium-ion screen membrane.

[0010] The method for preparing the precursor sol of the symbiotic structure layer in step S2 above is as follows: the raw materials of the main material of the symbiotic structure layer are mixed using the sol-gel method to prepare a sol.

[0011] The precursor sol prepared in step S2 above is an acidic TiO2 sol.

[0012] In step S4 above, the spin coating speed is 3000 rpm and the time is 1 min; in step S5, the sintering temperature is 500℃ and the holding time is 1 h.

[0013] The aforementioned symbiotic lithium-ion membrane can be used for extracting lithium resources from seawater or brine, or in lithium batteries.

[0014] Beneficial effects: 1. The symbiotic structure layer lithium-ion sieve film prepared by this invention contains a lattice-matched interface phase, effectively eliminating the additional interface resistance caused by traditional coatings and constructing a continuous Li... +1. A rapid transmission channel minimizes ion conduction loss, ensuring high ionic conductivity of the symbiotic lithium-ion membrane. 2. The outer inorganic layer of the symbiotic lithium-ion membrane prepared by this invention exhibits extremely strong chemical stability, effectively preventing direct contact between seawater and the inorganic solid lithium-ion membrane, thus avoiding corrosion by seawater. The overall seawater resistance of the symbiotic lithium-ion membrane far exceeds that of traditional inorganic solid lithium-ion membranes. 3. When the symbiotic lithium-ion membrane prepared by the method of this invention is applied to a combined electrolyte seawater lithium extraction system, it can operate stably for 650 hours, significantly improving the stability of the inorganic solid lithium-ion membrane. 4. The process for preparing the symbiotic lithium-ion membrane proposed in this invention is simple, cost-controllable, and easy to scale up for production, providing feasible technical support for the industrialization of seawater lithium extraction technology. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the symbiotic structure lithium-ion sieve membrane of the present invention.

[0016] Figure 2 This is a schematic diagram of the cross-sectional structure of the symbiotic lithium-ion sieve membrane of the present invention.

[0017] Figure 3 This is a planar scanning electron micrograph of a lithium-ion sieve membrane based on the symbiotic structure of this invention.

[0018] Figure 4 These are transmission electron micrographs of the interface of the symbiotic lithium-ion sieve membrane based on the present invention. a shows the overall morphology at the interface between the symbiotic structure layer and the solid lithium-ion sieve membrane; b shows the selected electron diffraction pattern of the lattice-matched interface phase between the symbiotic structure layer and the solid lithium-ion sieve membrane; c shows the high-resolution transmission electron micrograph of the lattice-matched interface phase in the red box area of ​​a.

[0019] Figure 5 This is an electrochemical impedance spectroscopy diagram of a symbiotic lithium-ion sieve membrane based on the present invention.

[0020] Figure 6 The graph shows the lithium extraction test results of the symbiotic structure lithium-ion sieve membrane based on the present invention; where a is the potential curve of the lithium extraction process and the gradual appearance of metallic lithium on the surface of the copper foil (product collection carrier); b is the scanning electron microscope image of the metallic lithium product; c is the phase analysis X-ray diffraction pattern of the metallic lithium product on the copper foil surface.

[0021] Figure 7 This is a graph showing the lithium extraction stability test results of the lithium-ion sieve membrane with symbiotic structure layer based on the present invention.

[0022] The labels in the figure are as follows: 1. Inorganic solid lithium-ion sieve membrane; 2. Symbiotic structure layer; 3. Protective layer (TiO2 layer); 4. Lattice matching interface layer between TiO2 layer and inorganic solid lithium-ion sieve membrane. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0025] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the materials and reagents used are commercially available.

[0026] The acidic TiO2 sols induced in the following examples can be obtained from the literature "CM Malengreaux, A. Timmermans, SL Pirard, SD Lambert, J.-P. Pirard, D. Poelman, B. Heinrichs. "Optimized deposition of TiO2 thin films produced by a non-aqueous sol-gel method and quantification of their photocatalytic activity". Chem. Eng. J. The method is reported in "https: / / doi.org / 10.1016 / j.cej.2012.04.076", 2012, 195-196, 347-358.

[0027] This invention provides a method for preparing a symbiotic structure layer lithium-ion sieve membrane and its application in seawater lithium extraction. The symbiotic structure layer lithium-ion sieve membrane includes an inorganic lithium-ion sieve membrane and a symbiotic structure layer grown on the surface of the inorganic solid lithium-ion sieve membrane. The symbiotic structure layer consists of an outermost protective layer and a lattice-matching interface phase between the protective layer and the inorganic lithium-ion sieve membrane. The lattice-matching interface phase is formed during the process of the main material of the symbiotic structure layer permeating and growing into the inorganic solid lithium-ion sieve membrane structure and being reconstructed through ion exchange and sintering.

[0028] Preferably, the inorganic lithium-ion sieve membrane comprises an inorganic solid electrolyte; the inorganic solid electrolyte comprises any one of NASICON structure oxide, perovskite structure oxide, and garnet structure oxide.

[0029] Preferably, the NASICON structure oxide is Li 1+x Al x Ge 2-x (PO4)3 and Li 1+x Al x Ti 2-x (PO4)3, 0.2≤x≤0.8; the garnet-structured oxide is Li 7-y La3Zr 2-y Ta y O 12 , 0≤y≤1; the perovskite structure oxide is Li 3z La 2 / 3-z TiO3, 0 < z ≤ 2 / 3.

[0030] Preferably, the main material of the symbiotic structural layer is stable to seawater and can transport Li + TiO2.

[0031] A method for preparing a symbiotic lithium-ion sieve membrane includes the following steps: S1. Preparation of inorganic solid lithium-ion sieve membranes; S2. Preparation of sol-gel precursors for symbiotic structural layers; S3. Polish the surface of the inorganic solid lithium-ion sieve membrane described in step (S1); S4. Spin-coating the symbiotic structure layer precursor sol described in step (S2) onto the polished surface of the inorganic solid lithium-ion sieve membrane treated in step (S3); S5. The inorganic solid lithium-ion sieve membrane containing the precursor sol of the symbiotic structure layer after step (S4) is sintered; S6. If necessary, repeat steps (S4) and (S5) until the observed symbiotic structure layer completely covers the surface of the inorganic solid lithium-ion sieve membrane, and finally obtain the symbiotic structure lithium-ion sieve membrane.

[0032] Preferably, in step (S1), the method for preparing the inorganic solid lithium-ion sieve membrane includes the following steps: a. Ingredients: Weigh the raw materials according to the chemical ratio of the target inorganic solid lithium-ion membrane; b. Ball milling: The raw materials are ball-milled; c. Heat treatment: The ball-milled precursor is subjected to heat treatment; d. Ball milling: The heat-treated precursor is ball-milled; e. Sintering: The ball-milled and heat-treated precursor is sintered to obtain inorganic solid lithium-ion sieve powder; f. Pressing: Press the obtained inorganic solid lithium-ion screen membrane powder into sheets to obtain inorganic solid lithium-ion screen membrane green blanks; g. Sintering: The inorganic solid lithium-ion screen membrane green body is sintered to obtain an inorganic solid lithium-ion screen membrane.

[0033] Preferably, in step (S2), the method for obtaining the symbiotic structure layer precursor sol includes the following steps: a. Ingredients: Weigh the raw materials according to the main materials of the symbiotic structural layer; b. Sol preparation: The raw materials of the main material of the symbiotic structural layer are mixed using the sol-gel method to prepare a sol; Preferably, in step (S2), the synthesized precursor sol is an acidic TiO2 sol.

[0034] Preferably, in step (S3), the grinding and polishing method includes, but is not limited to, using instruments and equipment such as nano sandpaper and polishing machines.

[0035] Preferably, in step (S4), the step of spin-coating the precursor sol of the symbiotic structure layer on the surface of the inorganic solid lithium-ion sieve membrane is as follows: a. Fix the inorganic solid lithium ion sieve onto the suction cup of the spin coater; b. A certain amount of symbiotic structure layer precursor sol is dropped onto the polished surface of an inorganic solid lithium-ion sieve membrane; c. Set the spin coater speed and time to ensure that the symbiotic structure layer precursor sol is evenly covered on the surface of the inorganic solid lithium ion sieve membrane; Preferably, the symbiotic lithium-ion sieve membrane prepared by (S1)-(S6) includes a protective layer that provides protection and a lattice-matching interface between the protective layer and the inorganic solid lithium-ion sieve membrane. The lattice-matching interface achieves a tight bond between the protective layer and the inorganic solid lithium-ion sieve membrane, ensuring protection, improving the stability of the inorganic solid lithium-ion sieve membrane, and guaranteeing continuous Li... + Transmission channel.

[0036] The symbiotic lithium-ion membrane can be used in lithium resource extraction, recycling, and lithium batteries.

[0037] Because the symbiotic structure lithium-ion sieve membrane prepared in this invention contains a stable TiO2 layer that prevents direct contact between seawater and the inorganic solid lithium-ion sieve membrane, it blocks chemical corrosion from seawater and improves stability. Simultaneously, since the interface between the solid lithium-ion sieve membrane and the TiO2 layer is a lattice-matched interface layer formed by a permeation growth strategy, it ensures the stability of the Li-ion sieve membrane. + The continuous transmission channel results in a symbiotic lithium-ion sieve membrane with excellent ionic conductivity. Ions cannot pass through the composite membrane, thus exhibiting high selectivity for lithium ions. It can be applied to lithium extraction from seawater, lithium extraction from brine, and lithium batteries (including but not limited to lithium-ion batteries and lithium metal batteries).

[0038] Example 1 This embodiment provides a method for preparing an inorganic solid lithium-ion sieve membrane, comprising the following steps: weighing Li₂CO₃, Al₂O₃, GeO₂, and NH₄H₂PO₄ precursors in a mass ratio of 0.74 g : 0.305 g : 1.878 g : 4.128 g; ball milling the precursors at a ball-to-material ratio of 4:1 at 400 rpm, milling for 20 min followed by a 10 min rest period, repeating this cycle 12 times; heat-treating the raw materials by heating to 600 °C at a rate of 2 °C / min, holding for 1 h, and then allowing them to cool naturally; ball milling the heat-treated precursors again at a ball-to-material ratio of 4:1 at 400 rpm, milling for 20 min followed by a 5 min rest period, repeating this cycle 20 times; and finally heating to 900 °C at a rate of 2 °C / min, holding for 6 h, and then allowing them to cool naturally to obtain the Li₂CO₃ precursor. 1.5 Al 0.5 Ge 1.5 (PO4)3 (LAGP) powder; Weigh 0.5g of LAGP powder, and press the LAGP green preform under a pressure of 9MPa using a stainless steel mold with a diameter of 16mm; Heat the LAGP green preform to 900℃ at 2℃ / min, hold for 6h and then cool naturally to obtain an inorganic solid lithium ion sieve membrane LAGP membrane with a thickness of about 1mm.

[0039] Example 2 This embodiment provides a method for preparing acidic TiO2 sol, comprising the following steps: weighing 9.95 g of tetraisopropoxy titanium and placing it in a three-necked flask containing 100 mL of anhydrous isopropanol; stirring the above solution at 1000 rpm for 30 min under nitrogen gas protection at 30°C; adding 1.05 g of acetylacetone and continuing to stir at 1000 rpm for 1 h; adding 6 g of glacial acetic acid and continuing to stir at 1000 rpm for 1 h to obtain a transparent yellow TiO2 sol, which is acidic.

[0040] Example 3 This embodiment provides a method for preparing a symbiotic structure layer lithium-ion sieve membrane, comprising the following steps: 1. Polishing one side of the inorganic solid lithium-ion sieve membrane LAGP synthesized in Example 1 until smooth, the thickness of the polished solid lithium-ion sieve membrane being 0.86-0.90 mm. 2. Dropping 0.05 mL of the acidic TiO2 sol synthesized in Example 2 onto the polished surface of the LAGP membrane with a diameter of 16 mm. 3. Using a spin coater, spin coating is performed at a speed of 3000 rpm for 1 min to ensure that the sol is coated on the entire polished surface of the LAGP. 4. The LAGP membrane with the TiO2 sol spin-coated is placed in a muffle furnace and heated to 500℃ at a heating rate of 10℃ / min, held at that temperature for 1 h, and then naturally cooled to room temperature. 5. The surface morphology of the membrane is observed using a scanning electron microscope. If there are exposed areas on the membrane surface that are not covered by TiO2, the spin coating-sintering process in steps 2 to 4 is repeated until the membrane surface is completely and uniformly covered by the TiO2 layer. In this embodiment, after three spin-coating-sintering cycles, the membrane surface achieves complete coverage, ultimately yielding a symbiotic structure LAGP lithium-ion sieve membrane. Figure 1 This is also known as a symbiotic LAGP lithium-ion sieve membrane, in which the upper layer is TiO2 and the lower layer is an inorganic solid lithium-ion sieve membrane. A lattice-matched interface phase exists between the TiO2 layer and the inorganic solid lithium-ion sieve membrane. Scanning electron microscopy was used to examine the symbiotic LAGP lithium-ion sieve membrane, and the results are as follows: Figure 2-3 As shown. From Figure 2 As can be seen, the top layer is a TiO2 layer, and the bottom layer is a LAGP lithium-ion sieve membrane. Figure 3 This indicates that the surface is uniform and flat.

[0041] Example 4 In this embodiment, the symbiotic structure LAGP lithium-ion sieve membrane is the same as in Example 3. The interface was characterized using transmission electron microscopy, and the thickness of the symbiotic structure layer was 300 nm. Figure 4 a). It was found that the interface is a mixed multiphase region of LATP / LAGP, with a tight connection between the TiO2 layer and the LAGP film, and no gaps in between. Figure 4 :b and Figure 4:c). This is because LATP and LAGP have similar crystal structures, and Ti 4+ Lattice sites in LATP and Ge 4+ The lattice sites in LAGP are interconnected, therefore Ti in TiO2 4+ It can penetrate and grow into the LAGP lattice and interact with Ge. 4+ Exchange occurs, generating a LATP / LAGP mixed multiphase region. This multiphase region eliminates the redundant interface between the TiO2 layer and the LAGP film, facilitating the construction of a continuous Li... + Transmission channel.

[0042] Example 5 The symbiotic LAGP lithium-ion sieve membrane in this embodiment is the same as that in Example 3. The electrochemical impedance of the symbiotic LAGP lithium-ion sieve membrane in this embodiment was tested at room temperature, and the test results are as follows: Figure 5 As shown. Calculations show that the ionic conductivity of the LAGP-PE composite lithium-ion sieve membrane in this embodiment can reach 2.40 × 10⁻⁶. -4 The S / cm value basically meets the requirements for ionic conductivity during lithium extraction at room temperature.

[0043] Example 6 In this embodiment, the symbiotic LAGP lithium-ion membrane is the same as in Example 3. The symbiotic LAGP lithium-ion membrane can achieve the extraction of metallic lithium from seawater. Figure 6 :a is the potential curve of the lithium extraction process and the gradual appearance of metallic lithium on the surface of the copper foil (product collection carrier); Figure 6 b indicates that the thickness of the lithium metal product is 80 μm; Figure 6 The 'c' indicates that the product on the copper foil surface after lithium extraction is metallic lithium, suggesting that the symbiotic LAGP lithium-ion membrane can be used for lithium extraction from seawater.

[0044] Example 7 In this embodiment, the symbiotic structure LAGP lithium-ion screen membrane is the same as in Example 3. For example... Figure 7 As shown, the symbiotic structure LAGP lithium-ion sieve membrane (red line in the figure) can work stably for 650 hours during the lithium extraction process from seawater. In contrast, the traditional LAGP lithium-ion sieve membrane (blue line in the figure) fails after only 150 hours. This indicates that our designed symbiotic structure successfully improves the stability of inorganic lithium-ion sieve membranes.

[0045] The above-described embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A symbiotic lithium-ion sieve membrane, characterized in that, include: Inorganic lithium-ion sieve membrane; The symbiotic structure layer grows on the surface of the inorganic lithium-ion sieve membrane; wherein the symbiotic structure layer includes a protective layer and a lattice-matching interface phase located between the protective layer and the inorganic lithium-ion sieve membrane, the lattice-matching interface phase being formed by the main material of the protective layer penetrating into the inorganic lithium-ion sieve membrane and then being reconstructed.

2. The symbiotic lithium-ion sieve membrane according to claim 1, characterized in that, The inorganic lithium-ion sieve membrane is composed of an inorganic solid electrolyte; the inorganic solid electrolyte is selected from any one of NASICON structure oxides, perovskite structure oxides, or garnet structure oxides.

3. The symbiotic lithium-ion sieve membrane according to claim 2, characterized in that, The NASICON structure oxide is Li 1+x Al x Ge 2-x (PO4)3 and Li 1+x Al x Ti 2-x (PO4)3, 0.2≤x≤0.8; the garnet-structured oxide is Li 7- y La3Zr 2-y Ta y O 12 , 0≤y≤1; the perovskite structure oxide is Li 3z La 2 / 3-z TiO3, 0<z≤2 / 3.

4. The symbiotic lithium-ion sieve membrane according to claim 1, characterized in that, The main material of the protective layer is capable of transporting Li. + TiO2.

5. A method for preparing a symbiotic lithium-ion sieve membrane as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Prepare an inorganic solid lithium-ion sieve membrane; S2. Prepare a precursor sol for the symbiotic structure layer; S3. Polish the surface of the inorganic solid lithium-ion sieve membrane prepared in step S1; S4. Spin-coat the precursor sol described in step S2 onto the polished surface of the inorganic solid lithium-ion screen membrane after step S3; S5. Sinter the inorganic solid lithium-ion screen membrane after step S4; S6. Repeat steps S4 and S5 at least once until the symbiotic structure layer completely covers the surface of the inorganic solid lithium-ion screen membrane to obtain the symbiotic structure lithium-ion screen membrane.

6. The preparation method according to claim 5, characterized in that, The method for preparing inorganic solid lithium-ion screen membrane in step S1 includes: weighing raw materials according to the chemical ratio of the target inorganic solid lithium-ion screen membrane, ball milling, heat treatment, ball milling again, and sintering to obtain inorganic solid lithium-ion screen membrane powder; pressing the powder into a green blank and sintering it to obtain inorganic solid lithium-ion screen membrane.

7. The preparation method according to claim 5, characterized in that, The method for preparing the precursor sol of the symbiotic structure layer in step S2 is as follows: the raw materials of the main material of the symbiotic structure layer are mixed using the sol-gel method to prepare a sol.

8. The preparation method according to claim 7, characterized in that, The precursor sol prepared in step S2 is an acidic TiO2 sol.

9. The preparation method according to claim 5, characterized in that, In step S4, the spin coating speed is 3000 rpm and the time is 1 min; in step S5, the sintering temperature is 500℃ and the holding time is 1 h.

10. The application of the symbiotic structure lithium-ion membrane according to any one of claims 1-4 in the extraction of lithium resources from seawater or brine, or in lithium batteries.

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