A titanium-based lithium ion sieve based on light assistance, synthesis method and application

Abstract

The present invention belongs to materials science and chemical engineering, and specifically relates to a light-assisted titanium-based lithium ion sieve, a synthesis method, and applications. A light-assisted titanium-based lithium ion sieve synthesis method comprises the following steps: S1: mixing a titanium source and a lithium source, dissolving them in a solvent, grinding to obtain a mixture, drying the mixture, and heating it in an air atmosphere to obtain a metatitanate-orthotitanate composite material precursor; S2: adding a solvent and a metal source to the metatitanate-orthotitanate composite material precursor of S1, grinding and drying to obtain a mixed powder, heating the powder to obtain a metal source-doped orthotitanate-metatitanate composite material, and immersing the metal source-doped orthotitanate-metatitanate composite material in an acid solution to obtain the titanium-based lithium ion sieve.

Description

Technical Field

[0001] The present invention belongs to materials science and chemical engineering, and specifically relates to a titanium-based lithium ion sieve based on light assistance, a synthesis method and an application. Background Art

[0002] With the rapid development of energy storage technology, electric vehicles, and 3C (computer, communications, and consumer electronics) products, the demand and production of lithium-ion batteries have increased rapidly, and the consumption of lithium resources has also increased dramatically. Since approximately 70% of the world's lithium resources exist in liquid phase, including salt lakes, brine, and seawater, the development of low-cost and efficient liquid phase lithium resource extraction technology is urgently needed.

[0003] At present, the main technology for extracting lithium from brine is the lime-soda evaporation method based on evaporation technology. However, this method requires a long cycle (usually one to two years) to produce lithium from brine. In addition, the large amount of water consumption and waste generation reduces its energy efficiency, which has a greater impact on the fragile ecological environment in the high-altitude areas where salt lakes are located. In comparison, the liquid phase adsorption method based on lithium ion sieve materials is a very promising lithium extraction method due to its advantages such as low energy consumption, high lithium absorption capacity, environmental friendliness and excellent lithium selectivity. It is considered to be one of the most promising liquid phase lithium extraction technologies for commercialization.

[0004] Commonly used lithium ion sieve materials include manganese-based lithium ion sieve (LMO) and titanium-based lithium ion sieve (LTO). The severe dissolution loss of Mn during acid elution in manganese-based lithium ion sieves negatively impacts cycling stability. In contrast, titanium-based lithium ion sieves, due to the presence of Ti-O bonds, offer superior chemical stability and have been widely used in liquid-phase lithium extraction. Titanium-based materials primarily include orthotitanic acid and metatitanic acid. Orthotitanic acid exhibits excellent adsorption kinetics but low adsorption capacity, while metatitanic acid exhibits excellent adsorption capacity but poor adsorption kinetics, making both insufficient for commercial applications. To combine the advantages of both, researchers have proposed combining the two and leveraging the interphase's ability to regulate lithium ion solid-phase transport to achieve rapid lithium ion adsorption and desorption. However, the interphase electric field between the two phases is limited and single-phase. Research remains to be conducted on how to enhance the interphase electric field strength and achieve faster kinetics in both adsorption and desorption processes through external field assistance. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the present invention provides a method for synthesizing a titanium-based lithium ion sieve based on light-assisted irradiation, comprising the following steps:

[0006] S1: mixing a titanium source and a lithium source, dissolving them in a solvent, grinding to obtain a mixture, drying the mixture, and heating it in an air atmosphere to obtain a metatitanate-orthotitanate composite material precursor;

[0007] S2: Add a solvent and a metal source to the metatitanate orthotitanate composite material precursor of S1, grind and dry to obtain a mixed powder, heat the powder to obtain a metal source-doped orthotitanate orthotitanate composite material, and soak the metal source-doped orthotitanate orthotitanate composite material in an acid solution to obtain a zinc-doped metatitanate orthotitanate inhibition structure lithium ion sieve, i.e., a titanium-based lithium ion sieve.

[0008] Furthermore, the mass ratio of the titanium source to the lithium source described in S1 is 3:1-1:2.

[0009] Furthermore, the temperature in the heating process described in S2 is 500-1000° C. and the time is 1 to 4 hours.

[0010] Furthermore, the mass ratio of the metal source in S2 to the orthotitanate-metatitanate composite material in S1 is 1:20-1:80.

[0011] Furthermore, the temperature of the heating process described in S1 is 700° C. to 800° C., and the heating time is 4 hours.

[0012] Furthermore, the lithium source described in S1 is any one of lithium carbonate, lithium acetate, and lithium oxide.

[0013] Furthermore, the metal source described in S2 is any one of salts and oxides, sulfides, selenides and halides containing transition metals.

[0014] Furthermore, the titanium source described in S1 is any one of titanium dioxide, amorphous titanium dioxide, and hydrated titanium dioxide intermediates.

[0015] A titanium-based lithium ion sieve based on light assistance has a heterogeneous structure of uniformly composited metatitanic acid and orthotitanic acid.

[0016] The invention discloses an application of a titanium-based lithium ion sieve based on light assistance, wherein the titanium-based lithium ion sieve is used in the preparation of a high-efficiency lithium ion sieve.

[0017] Beneficial effects

[0018] (1) The present invention provides a method for synthesizing titanium-based lithium ion sieves based on light-assisted sintering. This method constructs abundant phase boundaries inside the lithium ion sieve material through simple solid-phase sintering and acid treatment, and further enhances the electron transfer at the interface between the two phases through selective doping of metal ions. Due to the additional driving force of the enhanced space charge region at the phase boundary, Li + It can be quickly transferred between the two phases. However, this force is only unidirectional and cannot accelerate both the adsorption and desorption processes. Therefore, based on the generally good light conditions in salt lake areas, a method based on light regulation of space charge regions to enhance the dynamics of the dual process of lithium ion adsorption and desorption is proposed.

[0019] (2) The light-assisted titanium-based lithium ion sieve provided by the present invention can achieve a carbon content of 22.95 mg·g under the action of the space charge region even under neutral conditions. -1 The capacity can reach up to 13.10 mg g during lithium extraction. -1 ·h -1 Li + The absorption rate is effectively regulated by light to achieve the effective regulation of the space charge area, further optimizing the lithium extraction performance of the material, which shows a high absorption rate of 25.13 mg g under neutral conditions. -1 The lithium extraction capacity can reach 14.92 mg g -1 ·h -1 Li + The absorption rate is high, and the acid washing desorption efficiency is as high as 99.5%; it shows excellent lithium ion adsorption and desorption performance. This work is of great significance for accelerating the practical commercial application of titanium-based lithium ion sieve materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following is a brief introduction to the drawings required for use in the examples. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those skilled in the art, other relevant drawings can be obtained based on these drawings without creative work.

[0021] In the picture:

[0022] Figure 1 XRD patterns of Examples 1 to 3 of the present invention;

[0023] Figure 2 are morphology images of Examples 1 to 3 of the present invention;

[0024] Figure 3 This is a graph showing the lithium extraction performance of Examples 1 to 3 of the present invention;

[0025] Figure 4 These are the dissolution loss diagrams of titanium in Examples 1 to 3 of the present invention. DETAILED DESCRIPTION

[0026] The following is a summary of the embodiments of the present invention and the accompanying drawings. Figures 1 to 4 The present invention clearly and completely describes the technical solution of the present invention. It is obvious that the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0027] This article provides a method for synthesizing titanium-based lithium ion sieves based on light-assisted irradiation, comprising the following steps:

[0028] S1: First, a titanium source and a lithium source are mixed by a solid phase method to prepare a heterostructure composite material precursor composed of metatitanate and orthotitanate, and the heterostructure composite material composed of metatitanate and orthotitanate is obtained after acid washing;

[0029] S2: The doping metal source and the composite material precursor are doped in proportion under high temperature and gas atmosphere to obtain a heterogeneous structure composite material precursor in which the metal is selectively doped into the titanate phase, and after acid washing, a metal-doped titanate-orthotitanate inhibition structure lithium ion sieve is obtained.

[0030] Example 1

[0031] S1: 1.65 g of lithium acetate and 1.25 g of titanium dioxide were mixed in ethanol, and then the mixture was ground for 30 minutes to ensure thorough mixing; the mixture was placed in a forced air drying oven and dried until the ethanol was completely volatilized; and the mixture was then heated at 700° C. in an air atmosphere for 4 hours to obtain a metatitanate-orthotitanate composite material precursor;

[0032] S2: Take 0.4g of heterostructure composite material precursor LTO, add 15ml of ethanol, add magnesium chloride, and the mass ratio of magnesium chloride to heterostructure composite material precursor is 1:80; then grind for 30 minutes to ensure sufficient mixing; obtain mixed powder; place the mixed powder in a forced air drying oven and dry it at 70°C for 50 minutes until the ethanol is completely volatilized; heat the mixed powder at 800°C in an air atmosphere for 4 hours; then soak the powder in a 0.25M HCl solution (solid-liquid ratio of 10g / L) for 24 hours to obtain a metal-doped metatitanate / orthotitanate heterostructure titanium-based lithium ion sieve.

[0033] Example 2

[0034] S1: lithium acetate and titanium dioxide are mixed in ethanol, and then the mixture is ground for 30 minutes to ensure thorough mixing; the mixture is placed in a forced air drying oven and dried until the ethanol is completely volatilized; and the mixture is then heated at 700° C. in an air atmosphere for 4 hours to obtain a metatitanate-orthotitanate composite material precursor;

[0035] S2: Take 0.4g of heterostructure composite material precursor LTO, add a certain amount of ethanol, add magnesium chloride, and the mass ratio of magnesium chloride to heterostructure composite material precursor is 1:40; then grind for 30 minutes to ensure sufficient mixing; obtain mixed powder; place the mixed powder in a blast drying oven and dry it at 70°C for 50 minutes until the ethanol is completely volatilized; heat the mixed powder at 800°C in an air atmosphere for 4 hours; then soak the powder in a 0.25M HCl solution (solid-liquid ratio of 10g / L) for 24 hours to obtain a metal-doped metatitanate / orthotitanate heterostructure titanium-based lithium ion sieve.

[0036] Example 3

[0037] S1: lithium acetate and titanium dioxide are mixed in ethanol, and then the mixture is ground for 30 minutes to ensure thorough mixing; the mixture is placed in a forced air drying oven and dried until the ethanol is completely volatilized; and the mixture is then heated at 700° C. in an air atmosphere for 4 hours to obtain a metatitanate-orthotitanate composite material precursor;

[0038] S2: Take 0.4 g of heterostructure composite material precursor LTO, add a certain amount of ethanol, add magnesium chloride, and the mass ratio of magnesium chloride to the heterostructure composite material precursor is 1:20; then grind for 30 minutes to ensure sufficient mixing; obtain a mixed powder; place the mixed powder in a blast drying oven and dry it at 70°C for 50 minutes until the ethanol is completely volatilized; heat the mixed powder at 800°C in an air atmosphere for 4 hours; then soak the powder in a 0.25M HCl solution (solid-liquid ratio of 10 g / L) for 24 hours to obtain a metal-doped metatitanate / orthotitanate heterostructure titanium-based lithium ion sieve.

[0039] The present invention provides a method for synthesizing a titanium-based lithium ion sieve based on light assistance. During the entire process, when the material is applied to a lithium extraction scenario, adsorption is carried out in a dark field, and desorption is carried out under natural light irradiation, which means "based on light assistance". The two-phase composite material obtained by this method has a unique heterogeneous structure and a space charge region, which affects the solid-phase transmission rate of lithium ions. The space charge region can be enhanced by doping with metal ions, and combined with the regulation of light, the extraction and removal of lithium ions are promoted respectively. The material preparation process of the present invention is simple, energy-saving and environmentally friendly, and low in cost. At the same time, it makes full use of the rich light resources in the western region where salt lakes are widely distributed, respectively enhances the adsorption and desorption rates, and improves the lithium extraction efficiency; and the method uses light to regulate the space charge region of the ion sieve during the adsorption and desorption process, so that its effect is enhanced during the adsorption process and weakened during the desorption process, and the lithium extraction performance of the material is optimized by the regulation mechanism of light on the space charge region.

Claims

1. A method for synthesizing a titanium-based lithium ion sieve based on light-assisted irradiation, characterized in that: The following steps are involved: S1: Mixing a titanium source and a lithium source, dissolving them in a solvent, grinding to obtain a mixture, drying the mixture, and heating it in an air atmosphere to obtain a metatitanate-orthotitanate composite material precursor; the lithium source is any one of lithium carbonate, lithium acetate, and lithium oxide; the titanium source is any one of amorphous titanium dioxide and a hydrated titanium dioxide intermediate product; S2: The precursor of the metatitanate orthotitanate composite material of S1 is added with a solvent and a metal source, ground and dried to obtain a mixed powder, and the powder is heated to obtain a metal source-doped orthotitanate orthotitanate composite material, and the metal source-doped orthotitanate orthotitanate composite material is immersed in an acid solution to obtain a metal source-doped metatitanate orthotitanate heterostructure lithium ion sieve, that is, a titanium-based lithium ion sieve based on light assistance, which is adsorbed in a dark field during lithium extraction and desorbed under natural light; the metal source is any one of a salt and oxide, sulfide, or selenide containing a transition metal; the mass ratio of the metal source in S2 to the orthotitanate orthotitanate composite material in S1 is 1:20-1:

80.

2. The method for synthesizing a titanium-based lithium ion sieve based on light-assisted method according to claim 1, characterized in that: The mass ratio of the titanium source to the lithium source described in S1 is 3:1-1:

2.

3. The method for synthesizing a titanium-based lithium ion sieve based on light-assisted method according to claim 1, characterized in that: The heating process described in S2 is performed at a temperature of 500-1000° C. for a time of 1 to 4 hours.

4. The method for synthesizing a titanium-based lithium ion sieve based on light-assisted method according to claim 1, characterized in that: The temperature of the heating process described in S1 is 700° C. to 800° C., and the heating time is 4 hours.

5. A light-assisted titanium-based lithium ion sieve obtained by the synthesis method according to any one of claims 1 to 4, characterized in that: The titanium-based lithium ion sieve has a heterogeneous structure in which metatitanic acid and orthotitanic acid are uniformly compounded.

6. The application of the light-assisted titanium-based lithium ion sieve according to claim 5, characterized in that: The titanium-based lithium ion sieve is used in the preparation of a high-efficiency lithium ion sieve. When extracting lithium, the titanium-based ion sieve is subjected to adsorption in a dark field and desorption under natural light.

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