A layered composite lithium-ion sieve of H2TiO3@GO and its preparation method

Abstract

The application provides a kind of H2TiO3@GO layered composite lithium ion sieve and a preparation method thereof, and belongs to the technical field of lithium ion sieve adsorption, characterized in that the active component of the ion sieve is the delithiated product H2TiO3 of the Li2TiO3 lithium ion sieve precursor, and the carrier is graphene oxide GO; the molar ratio of graphene oxide GO to H2TiO3 is (1.4-2.8):1; the crystal form of Li2TiO3 is the typical monoclinic crystal form β-Li2TiO3. The composite lithium ion sieve is used for selective adsorption and extraction of lithium ions in low-concentration geothermal water, salt lake brine and seawater. The H2TiO3@GO composite lithium ion sieve provided by the application has the advantages of fast adsorption rate, high adsorption capacity and good ion sieve structure stability, and the composite ion sieve is easy to separate from liquid solution, has good regeneration repeatability, and has good industrial application prospect.

Description

Technical Field

[0001] This invention relates to the field of ion sieve adsorption technology, and more particularly to an H2TiO3@GO layered composite lithium ion sieve and its preparation method, especially its application in the adsorption and extraction of liquid lithium resources. Background Technology

[0002] Lithium is the lightest element and is widely used in batteries, ceramics, glass, lubricants, refrigerants, the nuclear industry, and optoelectronics. Currently, lithium resources mainly come from two sources: lithium minerals and liquid lithium. Salt lakes account for 66% of the world's total lithium resources. Therefore, research on lithium extraction from salt lakes is of significant value and has broad prospects. However, because salt lake brine also contains large amounts of elements such as sodium, potassium, boron, and magnesium, the extraction process requires the separation and purification of impurity ions, with the separation of magnesium and lithium being the most difficult. Selective adsorption is a low-cost, environmentally friendly, and widely used method.

[0003] Titanium-based lithium-ion sieves have attracted considerable attention from researchers due to their high theoretical adsorption capacity, low solution loss, and good stability. However, improving the adsorption sites of titanium-based sieves and preparing high-capacity titanium-based lithium-ion sieves remains a significant challenge. Gu et al. prepared Li₂TiO₃ by reacting CH₃COOLi·2H₂O with TiO₂ via a sol-gel method. The Li₂TiO₃ had a particle size of only 70 nm and exhibited an adsorption capacity as high as 40.16 mg·g⁻¹ in high-concentration lithium solutions. -1 (Chemical Engineering Journal 350(2018)474-483). Hayashi used a high-temperature solid-state method to grow Li₂TiO₃ nanocrystals in a LiCl-LiOH molten salt mixture, and the prepared monodisperse Li₂TiO₃ had a very high specific surface area at the nanoscale (Crystal Growth & Design 19(2019)1377-1383). In addition, the reduction in the crystal size of the Li₂TiO₃ precursor led to a shortened ion exchange pathway, thereby improving the ion exchange capacity of Li. + The adsorption rate is high. However, this titanium-based ion sieve has drawbacks such as a long adsorption equilibrium time (>24h) and the nanoparticles being too fine to be suitable for industrial recycling when adsorbing low-concentration lithium solutions.

[0004] Graphene oxide (GO) has attracted much attention due to its high specific surface area as a soft carbon material, particularly in its adsorption and host-guest effects. GO is considered an excellent soft carbon material because of its two-dimensional porous structure, uniform pore size distribution, and high dispersibility. Furthermore, the edges of GO are rich in oxygen-containing functional groups, which can promote the binding of metal ions to form stable compounds. GO can also act as a polymerization inhibitor, effectively suppressing the aggregation of nanoparticles. Hu et al. found that λ-MnO2 / rGO exhibits good conductivity and more active sites in the electrode (Journal of Colloid and Interface Science 612(2022)392-400). However, the Jahn-Teller effect in λ-MnO2 leads to manganese dissolution, and the use of expensive reduced graphene oxide (rGO) as a support is detrimental to the industrial application of lithium extraction from salt lake brine.

[0005] Existing technologies show that titanium-based ion sieves suffer from slow adsorption rates and excessively fine particles that hinder full recycling and reuse, making them unsuitable for industrial production. Therefore, there is a need to design and develop lithium-ion sieves that are more conducive to high-rate adsorption and can be fully recycled and reused. Summary of the Invention

[0006] The purpose of this invention is to provide an H2TiO3@GO layered composite lithium ion sieve to overcome the shortcomings of the prior art; another purpose of this invention is to provide a method for preparing the above-mentioned ion sieve.

[0007] The technical solution adopted in this invention is: an H2TiO3@GO layered composite lithium-ion sieve, characterized in that the active component is H2TiO3, the delithiation product of the Li2TiO3 lithium-ion sieve precursor, and the support is graphene oxide (GO); the molar ratio of graphene oxide (GO) to H2TiO3 is (1.4-2.8):1; the morphology of the composite lithium-ion sieve is a porous sandwich structure; and the crystal form of the Li2TiO3 is the typical monoclinic β-Li2TiO3.

[0008] This invention also provides a method for preparing the above-mentioned Li2TiO3@GO layered composite lithium-ion sieve, which employs a sol-gel-solid-phase calcination method, and the specific steps are as follows:

[0009] ① Dissolve graphene oxide (GO) in deionized water to obtain solution A, then add lithium source and organic acid sequentially and mix thoroughly to prepare solution B; stir and perform gelation reaction at a certain temperature;

[0010] ②Then, add an ethanol solution of the titanium source to solution B and stir until a sol is formed; wherein, the molar ratio of graphene oxide (GO) to the titanium source is (1.4-2.8):1; the molar ratio of lithium source, organic acid, to titanium source is Li +Organic acids: Ti 4+ =1:(1.65-3.5):(0.1-0.5);

[0011] ③ After drying and cooling, calcination is carried out under N2 atmosphere and then cooled to obtain LTO@GO precursor;

[0012] ④ The precursor Li2TiO3@GO was subjected to acidification and delithiation to obtain H2TiO3@GO layered composite lithium-ion sieve.

[0013] The preferred lithium source in step ① is lithium acetate, lithium hydroxide, or lithium chloride.

[0014] The organic acid mentioned in step ① is preferably formic acid, glacial acetic acid, succinic acid, or citric acid.

[0015] The preferred temperature for the gelation reaction in step ① is 60-100℃.

[0016] The preferred titanium source in step ② is tetrabutyl titanate or tetraisopropyl titanate.

[0017] The preferred calcination temperature in step ③ is 450-750℃; the calcination time is 3-8h.

[0018] In preferred step ④, the acidification and delithiation process involves immersion in an acid solution. Preferably, the acid solution is hydrochloric acid, sulfuric acid, phosphoric acid, or nitric acid; the concentration of the acid solution is 0.1-0.3 mol·L⁻¹. -1 Soaking time is 12-24 hours.

[0019] This invention also investigates the industrial application of the composite lithium-ion sieve H2TiO3@GO in salt lake brine:

[0020] 1g of H2TiO3@GO was placed at 25℃ in a pH 8 solution containing Li. + Na + Ca 2+ K + and Mg 2+ The adsorption selectivity and saturation adsorption capacity of lithium ions were determined in 1 L of brine from a salt lake containing lithium ions. + Na + Ca 2+ K + and Mg 2+ The corresponding ion concentrations were 75.9, 238.6, 311.1, 398.9, and 200.7 mg·L⁻¹, respectively. -1 .

[0021] Beneficial effects:

[0022] 1. This invention is the first to use GO as a carrier, which also acts as an inhibitor to prevent agglomeration during the LTO formation process, thereby improving the adsorption capacity of β-H2TiO3 and significantly enhancing its cyclic adsorption and regeneration capabilities.

[0023] 2. The HTO@GO prepared by the sol-gel-solid phase calcination method of this invention has a crystal structure of π-π GO layered structure, in which HTO is contained in the layer, increasing the exposed surface of HTO active sites, which is conducive to the rapid adsorption of lithium ions.

[0024] 3. The HTO@GO prepared by this invention has a better morphology and a smaller average particle size. Therefore, the graphene oxide is rich in hydrophilic groups during adsorption, which is conducive to full contact with the solution and also to the rapid adsorption of lithium ions.

[0025] 4. The preparation process of this invention is simple, green and non-toxic, easy to operate, and can be used for large-scale production. The obtained lithium-ion adsorbent has broad application prospects in the field of continuous lithium extraction from salt lake brine. Attached Figure Description

[0026] Figure 1 The XRD patterns of Li2TiO3@GO and H2TiO3@GO prepared in Example 1 of this invention are shown.

[0027] Figure 2 This is a SEM image of the Li2TiO3@GO precursor prepared in Example 1 of this invention.

[0028] Figure 3 This is a SEM image of the H2TiO3@GO composite ion sieve prepared in Example 1 of this invention. Detailed Implementation

[0029] The following examples are only used to illustrate the best implementation of the present invention, and the scope of protection of the present invention is not limited to the specific implementation.

[0030] Example 1

[0031] Step 1. First, dissolve 0.17 g (0.014 mol) of graphene oxide in 30 mL of deionized water and sonicate it until completely dispersed. Label this solution A. Then, add 2.14 g (0.02 mol) of CH3COOLi·2H2O and 3 g (0.05 mol) of glacial acetic acid to solution A and stir magnetically at 80 °C for 30 min. Label this solution B. Next, add 3.4 g (0.01 mol) of Ti(OC4H9)4 to 20 mL of ethanol and stir. Then, slowly add the mixture dropwise to solution B. After a uniform gel forms, dry it at 110 °C for 10 h. Finally, calcine the resulting solid mixture at 650 °C under a N2 atmosphere for 5 h to obtain the Li2TiO3@GO precursor.

[0032] Step 2. Disperse 0.1g of Li₂TiO₃@GO powder in 100mL of 0.2mol·L⁻¹ -1 The mixture was acidified in HCl solution, stirred at 25°C for 12 hours, filtered and dried at 50°C for 4 hours to obtain H2TiO3@GO-1 composite lithium ion sieve.

[0033] XRD characterization of Li2TiO3@GO precursor and H2TiO3@GO composite ion sieve as follows: Figure 1 As shown in the XRD pattern, the synthesized Li2TiO3@GO precursor exhibits a uniform layered structure, which is a monoclinic β-Li2TiO3 structure. The Li2TiO3@GO-1 composite ion sieve sample shows characteristic peaks at 18.5°, 35.8°, and 43.6°, corresponding to the (002), (133), and (312) phase characteristic crystal planes of the β-Li2TiO3 phase in the composite ion sieve, respectively. From the SEM... Figure 2 and 3 It can be seen that the morphology of the prepared Li2TiO3@GO-1 precursor and H2TiO3@GO-1 composite ion sieve are both layered porous sandwich structures, and the molar ratio of GO:H2TiO3 is 1.4:1.

[0034] Example 2

[0035] Step 1. First, dissolve 0.085 g (0.007 mol) of graphene oxide in 30 mL of deionized water and sonicate it until completely dispersed. Label this solution A. Then, add 10.7 g (0.1 mol) of CH3COOLi·2H2O and 15 g (0.25 mol) of glacial acetic acid to solution A and stir magnetically at 60 °C for 1 h. Label this solution B. Then, add 3.4 g (0.01 mol) of Ti(OC4H9)4 to 20 mL of ethanol and stir. Slowly add this solution dropwise to solution B. After forming a uniform gel, dry it at 110 °C for 10 h. Finally, calcine the resulting solid mixture at 650 °C under a N2 atmosphere for 4 h to obtain the Li2TiO3@GO precursor.

[0036] Step 2. Disperse 0.1 g of Li₂TiO₃@GO powder in 100 mL of 0.1 mol·L⁻¹ -1 The mixture was acidified in HCl solution, stirred at 25°C for 16 hours, filtered and dried at 50°C for 4 hours to obtain H2TiO3@GO-2 composite lithium ion sieve.

[0037] The XRD characterization of the Li2TiO3@GO precursor H2TiO3@GO-2 composite ion sieve conforms to standard card JCDPS#33-0831. Their SEM images show a layered porous structure, and the molar ratio of GO:H2TiO3 is 1.4:1.

[0038] Example 3

[0039] Step 1. First, dissolve 0.34 g (0.028 mol) of graphene oxide in 30 mL of deionized water and sonicate it until completely dispersed. Label this solution A. Then, add 2.14 g (0.02 mol) of CH3COOLi·2H2O and 4.2 g (0.07 mol) of glacial acetic acid to solution A and stir magnetically at 70 °C for 1 h. Label this mixed solution (B). Next, add 3.14 g (0.01 mol) of Ti(OC4H9)4 to 20 mL of ethanol and stir. Then, slowly add the mixture dropwise to mixed solution (B). After forming a uniform gel, dry it at 110 °C for 10 h. Finally, calcine the resulting solid mixture at 650 °C under a N2 atmosphere for 6 h to obtain the Li2TiO3@GO precursor.

[0040] Step 2. Disperse 0.1g of Li₂TiO₃@GO powder in 100mL of 0.05mol·L⁻¹ -1 The mixture was acidified in H3PO4 solution, stirred at 25℃ for 24 h, filtered and dried at 50℃ for 4 h to obtain H2TiO3@GO-3 composite lithium ion sieve.

[0041] The XRD characterization of the Li2TiO3@GO precursor and the H2TiO3@GO-3 composite ion sieve conforms to the standard card JCDPS#33-0831. Their SEM images show a layered porous sandwich structure, and the molar ratio of GO:H2TiO3 is 2.8:1.

[0042] Example 4

[0043] Step 1. First, dissolve 0.25 g (0.02 mol) of graphene oxide in 30 mL of deionized water and sonicate it until completely dispersed. Label this solution A. Then, add 2.14 g (0.02 mol) of CH3COOLi·2H2O and 3.17 g (0.0165 mol) of citric acid to solution A and stir magnetically at 90 °C for 30 min. Label this solution B. Next, add 3.4 g (0.01 mol) of Ti(OC4H9)4 to 20 mL of ethanol and stir. Then, slowly add the mixture dropwise to solution B. After forming a uniform gel, dry it at 110 °C for 10 h. Finally, calcine the resulting solid mixture at 750 °C under a N2 atmosphere for 7 h to obtain the Li2TiO3@GO precursor.

[0044] Step 2. Disperse 0.1g of Li₂TiO₃@GO powder in 100mL of 0.3mol·L⁻¹ -1 The mixture was acidified in HCl solution, stirred at 25°C for 12 hours, filtered and dried at 50°C for 4 hours to obtain H2TiO3@GO-4 composite lithium ion sieve.

[0045] The XRD characterization of the Li2TiO3@GO precursor and the H2TiO3@GO-4 composite ion sieve conforms to the standard card JCDPS#33-0831. Their SEM images show a layered porous sandwich structure with a GO:H2TiO3 molar ratio of 2:1.

[0046] Example 5

[0047] Step 1. First, dissolve 0.085 g (0.007 mol) of graphene oxide in 30 mL of deionized water and sonicate it until completely dispersed. Label this solution A. Then, add 2.14 g (0.02 mol) of CH3COOLi·2H2O and 3.6 g (0.06 mol) of glacial acetic acid to solution A and stir magnetically at 100 °C for 30 min. Label this solution B. Then, add 1.42 g (0.01 mol) of isopropyl titanate Ti(OC3H7)4 to 20 mL of ethanol and stir. Slowly add this solution dropwise to solution B. After forming a uniform gel, dry it at 110 °C for 10 h. Finally, calcine the resulting solid mixture at 450 °C under a N2 atmosphere for 8 h to obtain the Li2TiO3@GO precursor.

[0048] Step 2. Disperse 0.1g of Li₂TiO₃@GO powder in 100mL of 0.2mol·L⁻¹ -1 The mixture was acidified in H2SO4 solution, stirred at 25℃ for 24 h, filtered and dried at 50℃ for 4 h to obtain H2TiO3@GO-5 composite lithium ion sieve.

[0049] The XRD characterization of the Li2TiO3@GO precursor H2TiO3@GO-5 composite ion sieve conforms to standard card JCDPS#33-0831. Their SEM images show a layered porous sandwich structure with a GO:H2TiO3 molar ratio of 1.4:1.

[0050] Example 6

[0051] Step 1. First, dissolve 0.17 g (0.014 mol) of graphene oxide in 30 mL of deionized water and sonicate it until completely dispersed. Label this solution A. Then, add 0.88 g (0.02 mol) of LiOH·H₂O and 3.9 g (0.033 mol) of succinic acid to solution A and stir magnetically at 80 °C for 30 min. Label this solution B. Next, add 2.84 g (0.01 mol) of isopropyl titanate Ti(OC₃H₇)₄ to 20 mL of ethanol and stir. Then, slowly add this solution dropwise to solution B. After forming a uniform gel, dry it at 110 °C for 10 h. Finally, calcine the resulting solid mixture at 650 °C under a N₂ atmosphere for 5 h to obtain the Li₂TiO₃@GO precursor.

[0052] Step 2. Disperse 0.1g of Li₂TiO₃@GO powder in 100mL of 0.2mol·L⁻¹ -1 The mixture was acidified in H2SO4 solution, stirred at 25℃ for 24 h, filtered and dried at 50℃ for 4 h to obtain H2TiO3@GO-6 composite lithium ion sieve.

[0053] The XRD characterization of the Li2TiO3@GO precursor H2TiO3@GO-6 composite ion sieve conforms to standard card JCDPS#33-0831. Their SEM images show a layered porous sandwich structure with a GO:H2TiO3 molar ratio of 1.4:1.

[0054] Example 7

[0055] Step 1. First, dissolve 0.34 g (0.028 mol) of graphene oxide in 30 mL of deionized water and sonicate it until completely dispersed. Label this solution A. Then, add 88 g (0.2 mol) of LiCl and 3.6 g (0.6 mol) of acetic acid to solution A and stir magnetically at 60 °C for 30 min. Label this solution B. Next, add 6.8 g (0.02 mol) of Ti(OC4H9)4 to 20 mL of ethanol and stir. Then, slowly add the mixture dropwise to solution B. After forming a uniform gel, dry it at 110 °C for 10 h. Finally, calcine the resulting solid mixture at 750 °C under a N2 atmosphere for 5 h to obtain the Li2TiO3@GO precursor.

[0056] Step 2: Disperse 0.1g Li₂TiO₃@GO powder in 100mL of 0.2mol·L⁻¹ -1 The mixture was acidified in HNO3 solution, stirred at 25°C for 24 hours, filtered and dried at 50°C for 4 hours to obtain H2TiO3@GO-7 composite lithium ion sieve.

[0057] The XRD characterization of the Li2TiO3@GO precursor H2TiO3@GO-7 composite ion sieve conforms to standard card JCDPS#33-0831. Their SEM images show a layered porous sandwich structure with a GO:H2TiO3 molar ratio of 1.4:1.

[0058] Example 8

[0059] Step 1. First, dissolve 0.025 g (0.002 mol) of graphene oxide in 30 mL of deionized water and sonicate it until completely dispersed. Label this solution A. Then, add 0.88 g (0.02 mol) of LiOH·H₂O and 3 g (0.05 mol) of acetic acid to solution A and stir magnetically at 60 °C for 30 min. Label this solution B. Next, add 3.14 g (0.01 mol) of Ti(OC₄H₉)₄ to 20 mL of ethanol and stir. Then, slowly add the mixture dropwise to solution B. After forming a uniform gel, dry it at 110 °C for 10 h. Finally, calcine the resulting solid mixture at 450 °C under a N₂ atmosphere for 3 h to obtain the Li₂TiO₃@GO precursor.

[0060] Step 2. Disperse 0.1g of Li₂TiO₃@GO powder in 100mL of 0.2mol·L⁻¹ -1 The mixture was acidified in H3PO4 solution, stirred at 25℃ for 24 h, filtered and dried at 50℃ for 4 h to obtain H2TiO3@GO-8 composite lithium ion sieve.

[0061] The XRD characterization of the Li2TiO3@GO precursor H2TiO3@GO-8 composite ion sieve conforms to standard card JCDPS#33-0831. Their SEM images show a layered porous sandwich structure with a GO:H2TiO3 molar ratio of 2.5:1.

[0062] Example 9

[0063] Step 1. First, dissolve 0.025 g (0.002 mol) of graphene oxide in 30 mL of deionized water and sonicate it until completely dispersed. Label this solution A. Then, add 0.88 g (0.02 mol) of LiOH·H₂O and 2.76 g (0.06 mol) of formic acid to solution A and stir magnetically at 60 °C for 30 min. Label this solution B. Next, add 3.4 g (0.01 mol) of Ti(OC₄H₉)₄ to 20 mL of ethanol and stir. Then, slowly add the mixture dropwise to solution B. After forming a uniform gel, dry it at 110 °C for 10 h. Finally, calcine the resulting solid mixture at 650 °C under a N₂ atmosphere for 3 h to obtain the Li₂TiO₃@GO precursor.

[0064] Step 2. Disperse 0.1g of Li₂TiO₃@GO powder in 100mL of 0.2mol·L⁻¹ -1 The mixture was acidified in HCl solution, stirred at 25°C for 24 hours, filtered and dried at 50°C for 4 hours to obtain H2TiO3@GO-9 composite lithium ion sieve.

[0065] The XRD characterization of the Li2TiO3@GO precursor H2TiO3@GO-9 composite ion sieve conforms to standard card JCDPS#33-0831. Their SEM images show a layered porous sandwich structure with a GO:H2TiO3 molar ratio of 2.5:1.

[0066] Application Example 1

[0067] The adsorption capacity Q of H2TiO3@GO composite lithium ion sieve in salt lake brine was evaluated. e Equilibrium adsorption time selective adsorption in salt lake brine

[0068] (1) Adsorption capacity Q e and adsorption equilibrium time test:

[0069] Add 1g of H2TiO3@GO-x to 1L of LiOH solution (100mg·L⁻¹). -1 The stirring time was then measured. Subsequently, ICP (inductively coupled plasma) was used to measure the Li in the solution. +The initial and instantaneous concentrations of (C0) t ), C t Calculate the adsorption capacity Q until the concentration remains relatively stable over time. e and equilibrium adsorption time The adsorption capacity Q of H2TiO3@GO t It is calculated using formula (1).

[0070]

[0071] (2) Adsorption cycle test (calculated based on an 80% decrease in adsorption capacity):

[0072] 1g of H2TiO3@GO-x was placed in LiOH solution (100mg·L⁻¹). -1 The cycling performance of Li₂TiO₃@GO after adsorption was assessed by acid washing with 0.2 mol mg·L⁻¹. -1 Then, an adsorption experiment is conducted to observe the decrease in adsorption capacity. The calculation ends when the adsorption capacity decreases to less than 80%. The calculation formula for the test conditions is the same as formula (1).

[0073] (2) Adsorption selectivity test (using Li) + For Mg 2+ The separating factor is the subject of this study:

[0074] H2TiO3@GO1 g was placed at 25℃ in a solution containing Li at pH 8. + Na + Ca 2+ K + and Mg 2+ The adsorption selectivity of ions in salt lake brine for 24 h was investigated (the corresponding ion concentrations were 75.9, 238.6, 311.1, 398.9, and 200.7 mg·L⁻¹). -1 ). Measurement of Li in solution using ICP. + The initial and instantaneous concentrations (C0) of the hetero ions and their associated concentrations (C20) t Allocation coefficient (K) d ) and separation factor The results are obtained by formulas (2) and (3) respectively.

[0075]

[0076] The experimental results of the application example are shown in Table 1.

[0077] Table 1. Experimental Results of Application Examples

[0078]

Claims

1. A layered composite lithium-ion sieve of H2TiO3@GO, characterized in that, The active component is H2TiO3, a delithiation product of the Li2TiO3 lithium-ion sieve precursor, and the support is graphene oxide (GO). The molar ratio of graphene oxide (GO) to H2TiO3 is (1.4-2.8):

1. The Li2TiO3 has a typical monoclinic β-Li2TiO3 crystal form. It is prepared by the following method, the specific steps of which are as follows: Graphene oxide (GO) was dissolved in deionized water to prepare solution A. A lithium source and an organic acid were added sequentially and mixed thoroughly to prepare solution B. The mixture was stirred and gelled at 60-100 °C. Then, an ethanol solution of the titanium source was added to solution B, and the mixture was stirred until a sol was formed; wherein the molar ratio of graphene oxide (GO) to the titanium source was (1.4-2.8):1; the molar ratio of lithium source, organic acid, and titanium source was Li... + Organic acids: Ti 4+ = 1: (1.65-3.5): (0.1-0.5); After drying, cooling, calcination under N2 atmosphere, and cooling down, LTO@GO precursor is obtained; wherein the calcination temperature is 450-750 ℃; and the calcination time is 3-8 h. The precursor Li2TiO3@GO was subjected to acidification and delithiation to obtain H2TiO3@GO layered composite lithium-ion sieve.

2. The H2TiO3@GO layered composite lithium-ion sieve according to claim 1, characterized in that, step The lithium source mentioned is lithium acetate, lithium hydroxide, or lithium chloride.

3. The H2TiO3@GO layered composite lithium-ion sieve according to claim 2, characterized in that, step The organic acids mentioned are formic acid, glacial acetic acid, succinic acid, or citric acid.

4. The H2TiO3@GO layered composite lithium-ion sieve according to claim 2, characterized in that, step The titanium source mentioned is tetrabutyl titanate or tetraisopropyl titanate.

5. The H2TiO3@GO layered composite lithium-ion sieve according to claim 2, characterized in that, step The acidification and delithiation process described herein involves immersion in an acid solution.

6. The H2TiO3@GO layered composite lithium-ion sieve according to claim 5, characterized in that... The acid solution is a hydrochloric acid solution, sulfuric acid solution, phosphoric acid solution, or nitric acid solution; the concentration of the acid solution is 0.1-0.3 mol·L⁻¹. -1 Soaking time is 12-24 hours.

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