Ion sieve for selectively extracting lithium and preparation method and application thereof

Abstract

The present application relates to a kind of ion sieve of selective extraction lithium and its preparation method and application, the ion sieve includes lithium ion sieve base material, and the conductive carbon material doped pyrrole-based polymer coating layer of lithium ion sieve base material outer coating.This selective extraction lithium ion sieve can realize the repeated deintercalation of lithium ion by electrochemical means, suitable for salt lake lithium extraction and other lithium-containing solution lithium extraction system, with lower potential, high lithium ion selectivity, high deintercalation rate, high adsorption capacity, good stability, environment-friendly, cyclic performance is good and so on Characteristics, can effectively improve the lithium extraction efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium extraction, and particularly relates to a lithium ion sieve for selectively extracting lithium and a preparation method thereof, and application of the lithium ion sieve in lithium extraction from salt lake brine. BACKGROUND

[0002] Lithium is one of the key raw materials for new energy industries centered on lithium batteries, and its sources mainly include salt lake brine and ores. About 80% of lithium resources in China are distributed in salt lake brine in Qinghai, Tibet and other regions. Therefore, developing high-efficiency and low-cost salt lake lithium extraction technology is of great significance to ensure the healthy development of new energy industries.

[0003] The electrically controlled lithium extraction technology is a new type of salt lake lithium extraction technology combining lithium ion batteries and electrochemistry. The technology uses metal oxides similar to lithium battery electrode materials as electrode active components, which can selectively adsorb lithium ions. By applying a potential to change the oxidation-reduction state of the electroactive component, lithium ions can be reversibly adsorbed / desorbed from the solution to achieve lithium enrichment.

[0004] The commonly used electrochemical lithium ion sieve in the prior art is usually LiFePO4 with an olivine structure, LiMn2O4 and LiNi 0.5 Mn 1.5 O4 with a spinel structure, and Li(NiCoMn)O2 with a layered structure. CN102049237B discloses extracting lithium from a lithium-containing solution by using iron phosphate as a lithium ion sieve. Lithium extraction is achieved by adjusting the system potential by adding a reducing agent or adjusting the voltage of the external circuit. However, due to the strong covalent oxygen bond of lithium iron phosphate, its ion diffusion rate is low and its electrical conductivity is poor. In addition, its lithium potential is high, and the lithium extraction efficiency needs to be further improved. CN105600807B uses lithium manganate as an electrode material, and the de-lithiation and intercalation capacity of lithium is about 4mmol Li + / g, but the single electrochemical adsorption time is as long as 4-7 hours, and the extraction efficiency is low. In addition, the lithium manganate electrode also has the problems of manganese dissolution and poor electrical conductivity in seawater or brine. In order to avoid water decomposition, improve lithium extraction efficiency and reduce cost, it is urgent to develop an environmentally friendly lithium ion sieve with low potential, fast de-intercalation rate and high adsorption capacity. SUMMARY

[0005] The present application aims to overcome the deficiencies in the prior art, and provides an ion sieve for selectively extracting lithium and a preparation method thereof, and an ion sieve electrode for selectively extracting lithium and a preparation method thereof. The ion sieve for selectively extracting lithium is a lithium ion sieve coated with a pyrrole-based polymer doped with conductive carbon material, which can be used for electrochemical extraction of lithium from a lithium-containing solution such as brine, has the advantages of low potential, high lithium ion selectivity, high de-intercalation rate, high adsorption capacity, good stability, environmental friendliness, and the like, and can effectively improve the lithium extraction efficiency and cycle life.

[0006] In a first aspect, the present application provides an ion sieve for selectively extracting lithium, which comprises a lithium ion sieve substrate, and a conductive carbon material doped pyrrole-based polymer coating layer coated on the outside of the lithium ion sieve substrate.

[0007] In the present application, the conductive carbon material doped pyrrole-based polymer coating layer has a conductive carbon material doping amount of 0.05-20wt%, such as 0.05wt%, 0.1wt%, 0.5wt%, 1wt%, 5wt%, 10wt%, 15wt%, 20wt%, preferably 0.1-10wt%.

[0008] In the present application, the ion sieve for selectively extracting lithium has a particle size of 2-18μm, such as 2μm, 4μm, 6μm, 8μm, 10μm, 12μm, 14μm, 16μm, 18μm, preferably 3-15μm, more preferably 5-12μm.

[0009] In the present application, the ion sieve for selectively extracting lithium has a particle size distribution width (D 90 -D 10 ) / D 50 ≤1.2, such as 1.2, 1.0, 0.8, 0.6, 0.4, 0.2, 0.1, preferably (D 90 -D 10 ) / D 50 ≤0.7.

[0010] In the present application, the lithium ion sieve substrate is a lithium vanadium-based oxide having a disordered rock salt structure.

[0011] Preferably, the lithium ion sieve substrate has the general formula Li x M a V y O zwherein, 2.5≤x≤5, for example 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, preferably 2.8≤x≤4.85, more preferably 2.8≤x≤4; 0.8≤y≤2.5, for example 0.8, 1.0, 1.5, 2.0, 2.5, preferably 0.8≤y≤2.2, more preferably 1.8≤y≤2.2; 4.5≤z≤6, for example 4.5, 5.0, 5.5, 6.0, preferably 4.8≤z≤5.3, more preferably 4.8≤z≤5.1; 0≤a≤1.2, for example 0, 0.01, 0.1, 0.5, 1.0, 1.2, preferably 0≤a≤0.8, more preferably 0≤a≤0.5; M is selected from one or more of transition metals, alkaline earth metals, Al, B, preferably one or more of Ni, Co, Mo, Cr, Ti, Mn, Zr, Al, Mg, W, Y, Nb, Ta, Sr, Ce, B, more preferably one or more of Ni, Mo, Ti, Al, Nb, Ta, B.

[0012] The lithium vanadium-based oxide of the lithium ion sieve substrate in the present application is a product disclosed in the prior art, and the source thereof is not particularly required in the present application. It can be obtained by purchase on the market or self-preparation. For example, it can be prepared by referring to the methods disclosed in patents such as CN115520897A, CN113257583A, CN114613978A, US9059463B2, etc.

[0013] In the present application, the outer surface of the lithium ion sieve substrate is coated with a pyrrole-based polymer coating layer doped with conductive carbon material, wherein,

[0014] The conductive carbon material is selected from one or more of carbon fibers, carbon nanotubes and graphene;

[0015] The pyrrole-based polymer is a pyrrole-containing group polymer capable of forming intermolecular forces such as hydrogen bonds with water molecules, preferably one or more of polypyrrole, polypyrrole-3-carboxylic acid, polypyrrole-3-carboxaldehyde and 3-hydroxypyrrole.

[0016] The pyrrole-based polymer coating layer doped with conductive carbon material coated on the outside of the lithium ion sieve substrate in the present application is prepared by conventional technical means such as liquid phase coating. Such coating layer can be fully coated or island-shaped coated, i.e. part of the surface is coated with the coating layer, while part of the surface is not coated with the coating layer. The coating thickness may vary at different positions, but as much as possible to be uniformly distributed. The coating thickness at each position can be distributed within 0-500nm, for example 25nm, 50nm, 75nm, 100nm, 125nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, which is not specifically limited in the present application.

[0017] In a second aspect, the present application also provides a preparation method of the ion sieve for selectively extracting lithium, comprising the following steps:

[0018] The lithium ion sieve substrate, the conductive carbon material and the anionic surfactant are uniformly dispersed in a solvent, and then an initiator and a pyrrole-based polymer monomer are added for polymerization reaction, followed by water washing, alcohol washing, drying to obtain the ion sieve for selectively extracting lithium.

[0019] In the preparation method, the anionic surfactant is selected from one or more of sodium dodecyl sulfonate and sodium dodecyl benzene sulfonate;

[0020] The solvent is selected from one or more of water or alcohol, preferably one or more of water and ethanol;

[0021] The initiator is selected from one or more of ferric chloride, potassium permanganate, hydrogen peroxide and ammonium persulfate, preferably ferric chloride;

[0022] The pyrrole-based polymer monomer is selected from one or more of pyrrole, pyrrole-3-carboxylic acid, pyrrole-3-formaldehyde and 3-hydroxypyrrone.

[0023] In the preparation method, the mass ratio of the pyrrole-based polymer monomer to the conductive carbon material is 100:(0.05-20), for example 100:0.05, 100:0.1, 100:0.5, 100:1, 100:5, 100:10, 100:15 or 100:20, preferably 100:(0.1-10);

[0024] The mass ratio of the lithium ion sieve substrate to the conductive carbon material and the anionic surfactant is 10:(0.02-0.5):(0.1-2), for example 10:(0.02, 0.05, 0.1, 0.2, 0.3, 0.4 or 0.5):(0.1, 0.5, 1.0, 1.5 or 2.0), preferably 10:(0.04-0.2):(0.3-1);

[0025] The mass ratio of the lithium ion sieve substrate to the solvent is 1:(1-10), for example 1:1, 1:2, 1:4, 1:6, 1:8 or 1:10, preferably 1:(1.5-5);

[0026] The molar ratio of the pyrrole-based polymer monomer to the initiator is (2-20):1, for example 1:1, 5:1, 10:1, 15:1 or 20:1, preferably (5-10):1.

[0027] In the preparation method, the pyrrole-based polymer monomer can be added in one-time feeding mode, segmented feeding mode or continuous feeding mode, and the feeding time is included in the polymerization reaction time.

[0028] Preferably, the pyrrolyl polymer monomer is formulated into a solution before feeding, and the volume ratio of the pyrrolyl polymer monomer to the solvent is 1:1-50, such as 1:1, 1:10, 1:20, 1:30, 1:40, 1:50; wherein the solvent for the pyrrolyl polymer monomer is selected from one or more of water or alcohols, preferably one or more of water, ethanol.

[0029] In the preparation method of the present application, the polymerization reaction is carried out at a temperature ≤ 5°C, such as 5°C, 4°C, 3°C, 2°C, 1°C, 0°C, -1°C, -2°C, -3°C, preferably 0-5°C, more preferably under ice water bath conditions.

[0030] In the preparation method of the present application, the polymerization reaction is carried out for 7-18h, such as 7h, 10h, 15h, 18h, preferably 10-16h.

[0031] In the preparation method of the present application, the water washing, alcohol washing, and drying are conventional operations in the art, wherein the alcohol washing is preferably carried out using ethanol.

[0032] In a third aspect, the present application provides a selective lithium extraction ion-sieve electrode comprising the selective lithium extraction ion-sieve of the present application.

[0033] In a preferred example of the present application, the selective lithium extraction ion-sieve electrode is prepared by coating a slurry comprising the selective lithium extraction ion-sieve on a titanium mesh.

[0034] Specifically, it is prepared by coating a slurry comprising the selective lithium extraction ion-sieve, polyvinylidene fluoride (PVDF), and N-methyl pyrrolidone (NMP) on a titanium mesh.

[0035] In a fourth aspect, the present application provides a preparation method of the selective lithium extraction ion-sieve electrode.

[0036] The method is to stir the selective lithium extraction ion-sieve, polyvinylidene fluoride, and N-methyl pyrrolidone into a slurry, coat the slurry on a titanium mesh, and dry to obtain the selective lithium extraction ion-sieve electrode.

[0037] As a preferred, in some examples of the present application, the preparation method of the selective lithium extraction ion-sieve electrode comprises the following steps:

[0038] The ion-sieve selectively extracting lithium and polyvinylidene fluoride are mixed uniformly, added into N-methylpyrrolidone, stirred into a slurry, the slurry is coated on a titanium mesh, and the titanium mesh is dried at a temperature of 80-140℃, for example 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, preferably 100-130℃, for 3-24h, for example 3h, 5h, 10h, 15h, 20h, 24h, preferably 10-15h, to obtain an ion-sieve electrode selectively extracting lithium.

[0039] In the present application, the mass ratio of the ion-sieve selectively extracting lithium to polyvinylidene fluoride is 1:(0.03-0.2), for example 1:0.03, 1:0.05, 1:0.1, 1:0.15, 1:0.2, preferably 1:(0.05-0.15).

[0040] In the present application, the mass ratio of the ion-sieve selectively extracting lithium to N-methylpyrrolidone is 1:(0.7-1.2), for example 1:0.7, 1:0.8, 1:0.9, 1:1.0, 1:1.1, 1:1.2, preferably 1:(0.8-1.05).

[0041] In the present application, the coating density of the slurry on the titanium mesh is 0.05-0.5g / cm 2 , for example 0.05g / cm 2 , 0.1g / cm 2 , 0.2g / cm 2 , 0.3g / cm 2 , 0.4g / cm 2 , 0.5g / cm 2 , preferably 0.08-0.3g / m 2 .

[0042] It should be noted that the above-mentioned method is only one example of the preparation method of the ion-sieve electrode selectively extracting lithium, and the present application should not be limited by the steps and parameters in the above-mentioned method. In actual operation, other additives and additives may also be added during the preparation process, and the operation parameters such as proportion, content, temperature and time are not limited to the above-mentioned example, and the professional technicians in the field can make corresponding non-essential adjustments according to the needs.

[0043] For example, in the present application, in order to improve the conductivity of the system, a conductive agent such as one or more of graphite, graphene, carbon nanotubes, reduced graphene oxide (rGO), etc. is also optionally added to the slurry, and a titanium mesh coated with a carbon layer can also be optionally selected. The introduction of the conductive agent is a conventional technical means in the art, and the present application only selects the type of conductive agent, and other features such as the addition method and amount are not particularly limited, and the skilled person can select the appropriate type and amount of conductive agent according to the product needs.

[0044] In a fifth aspect, the present application provides the use of the selective lithium extraction ion-sieve electrode in the extraction of lithium from a lithium-containing solution such as brine.

[0045] The selective lithium extraction ion-sieve electrode of the present application can be used for lithium extraction from salt lake brine and other lithium-containing solutions, and is particularly suitable for high magnesium-lithium ratio (magnesium-lithium ratio ≥ 10, such as 10, 20, 30, 40, 50, 60, 70, 80, 90, 100) salt lake brine.

[0046] As a preferred embodiment, in one specific example of the present application, an electrochemical lithium extraction method in a lithium-containing solution such as brine is provided, which uses the selective lithium extraction ion-sieve electrode of the present application and is carried out in a diaphragm electrolytic cell, with an anion exchange membrane as the diaphragm of the electrolytic cell, dividing the electrolytic cell into a brine chamber and a lithium-rich chamber. The steps include:

[0047] 1) placing the selective lithium extraction ion-sieve electrode in the brine chamber, placing the counter electrode in the lithium-rich chamber, injecting the lithium-containing solution into the brine chamber, and injecting the KCl solution into the lithium-rich chamber;

[0048] 2) using the selective lithium extraction ion-sieve electrode as the cathode and the counter electrode as the anode, passing an electric current to carry out an electrochemical lithium extraction reaction, and embedding lithium ions in the ion-sieve electrode from the lithium-containing solution;

[0049] 3) after the electrochemical lithium extraction reaction is completed, interchanging the positions of the selective lithium extraction ion-sieve electrode and the counter electrode, passing an electric current to carry out a lithium extraction reaction, and achieving lithium enrichment in the lithium-rich chamber, thereby extracting lithium ions from the lithium-containing solution.

[0050] In the method of the present application, the counter electrode of step 1) is an activated carbon electrode or a graphite electrode.

[0051] In the method of the present application, the KCl solution of step 1) is an aqueous KCl solution with a concentration of 2-50 g / L, such as 2 g / L, 10 g / L, 20 g / L, 30 g / L, 40 g / L, 50 g / L, preferably 5-20 g / L.

[0052] In the method, the electrochemical lithium extraction reaction in step 2) is carried out at a temperature of -10-50℃, such as -10℃, 0℃, 10℃, 20℃, 30℃, 40℃ or 50℃, preferably 0-35℃, and for 1-10h, such as 1h, 2h, 4h, 6h, 8h or 10h, preferably 2-6h.

[0053] In the method, the electrochemical lithium extraction reaction in step 2) is carried out at a voltage of <1.3V between the electrodes, such as 1.29V, 1.2V, 1.0V, 0.8V, 0.6V, 0.4V or 0.2V, preferably 0.5-1V.

[0054] In the method, the lithium extraction reaction in step 3) is carried out at a temperature of -10-50℃, such as -10℃, 0℃, 10℃, 20℃, 30℃, 40℃ or 50℃, preferably 0-35℃, and for 1-10h, such as 1h, 2h, 4h, 6h, 8h or 10h, preferably 2-6h.

[0055] In the method, the lithium extraction reaction in step 3) is carried out at a voltage of <1.3V between the electrodes, such as 1.29V, 1.2V, 1.0V, 0.8V, 0.6V, 0.4V or 0.2V, preferably 0.5-1V.

[0056] In the method, the anion exchange membrane prevents the mutual migration of cations between the two regions of the brine chamber and the lithium-rich chamber, while anions can pass through the exchange membrane from the brine chamber into the lithium-rich chamber to maintain charge balance.

[0057] In the method, the electrolytic cell, such as the material of the electrolytic cell, the shape and arrangement of the electrodes in the electrolytic cell, etc., can be selected according to conventional methods in the field, and the present application does not make specific limitations.

[0058] The lithium extraction principle of the method is that the ion sieve electrode with selective lithium extraction is contacted with a lithium-containing solution such as brine, the system potential is adjusted to reduce vanadium in the ion sieve structure, lithium ions enter the lithium vanadate crystal lattice as a counterion, and magnesium ions remain in the lithium-containing solution due to their higher hydration energy and larger hydrated ion radius; then the generated lithium-embedded product is placed in a supporting electrolyte solution by exchanging the positions of the electrodes, and the system potential is adjusted to oxidize the vanadium in the structure, forcing the lithium ions in the crystal lattice to enter the solution to maintain the electrical neutrality of the solid phase, and the solid phase is reconverted into a lithium ion sieve in a delithiated state, and through the circulation of this process, Li + The delithiated lithium ion sieve is then contacted with a lithium-containing solution to circulate the above process, and finally the lithium is enriched.

[0059] The selective lithium extraction ion sieve in the application has a suitable particle size and a wide particle size distribution width, cooperates with the outer coated conductive carbon material doped polypyrrole, can make the lithium ion sieve composite material have a high particle strength, reduces the lithium ion transmission path, and can improve the stability of the electrode, avoids the active material particles from being pulverized and cracked in the use process, effectively improves the lithium extraction efficiency and the cycle life. On the one hand, in the coating layer, the polypyrrole is not soluble in water and has good stability, the contact between the internal lithium ion sieve matrix and the salt lake water is isolated to ensure the overall structural stability of the ion sieve, and the cycle performance is greatly increased; the surface of the doped conductive carbon material contains oxygen groups, can form hydrogen bonds with the polypyrrole-based polymer material, and the synergistic effect of the conductive carbon material and the polypyrrole-based polymer greatly enhances the structural stability and water impact resistance of the composite material. In addition, the polypyrrole, especially the carboxyl and hydroxyl substituted polypyrrole, has good hydrophilicity, can make the solvated ions pass through smoothly, and improves the rate performance. On the other hand, the internal lithium ion sieve is a lithium vanadium-based oxide, which has excellent ion conduction performance. The polypyrrole-based polymer and the conductive carbon material such as carbon fiber, graphene and carbon nanotube all have good conductivity, and the two form a three-dimensional network structure, which further improves the electron transmission capacity of the ion sieve and improves the rate performance.

[0060] Compared with the prior art, the technical scheme of the application has the beneficial effects that:

[0061] The lithium ion sieve described in the application can process brine with a high magnesium-lithium ratio, and has a high selectivity for Li + , good stability and high adsorption capacity. In one deintercalation cycle, it can have two Li + deintercalation, and the theoretical adsorption capacity can reach 68.5 mg / g. At the same time, it has a high lithium deintercalation and intercalation rate, which can improve the lithium extraction efficiency and reduce the cost.

[0062] The lithium ion sieve described in the application realizes selective adsorption and desorption of lithium by adjusting the potential of the system in use, instead of relying on adjusting the pH of the system, thereby overcoming the disadvantage of large dissolution of ion sieve type oxides in the traditional process. Since no acid solution is used, it is very friendly to the environment. And the lithium ion sieve described in the application has a low lithium potential compared with the existing lithium ion sieve for electrochemical lithium extraction, which can effectively avoid water decomposition and further improve the safety performance of the system. DETAILED DESCRIPTION

[0063] The method provided by the application will be further described below by using examples, but the application is not limited to the listed examples, and any known changes within the scope of the claimed rights of the application should also be included.

[0064] The main raw material source information in the examples and comparative examples of the application is as follows, and other materials not specifically mentioned are obtained from ordinary commercial channels:

[0065] Li3V2O5was prepared according to the method disclosed in CN113257583A; Li3Ni 0.1 V2O5was prepared according to the method disclosed in CN114613978A; Li 3.25 Mo 0.75 VO5was prepared according to the method disclosed in US20210184210A1;

[0066] Pyrrole, pyrrole-3-carboxylic acid, pyrrole-3-carboxaldehyde, 3-hydroxypyrrole, PVDF, NMP: Aldrich;

[0067] Polyether Wanhua Chemical Group Co., Ltd.

[0068] Anion exchange membrane: ASTOM-ACS of Japan ASTOM Co., Ltd.

[0069] Salt lake brine: on the one hand, the source of the salt lake brine has little effect on the lithium extraction effect of the present application, and on the other hand, the geographical location limits the use of actual salt lake brine, so the simulated salt lake brine is mostly used in the laboratory, which is prepared by dissolving raw materials including lithium chloride and magnesium chloride in water to prepare a simulated salt lake brine containing a certain amount of magnesium and lithium.

[0070] The main analysis methods used in the examples and comparative examples of the present application are as follows:

[0071] The ion concentration was determined by inductively coupled plasma emission spectrometer (Agilent 720-OES) and ion chromatograph (Wan Tong 881).

[0072] Example 1

[0073] 1) Preparation of ion sieve for selective extraction of lithium:

[0074] 20g of Li3V2O5, 0.1g of carbon nanotubes, and 0.7g of sodium dodecyl sulfonate were added to 50mL of deionized water and stirred uniformly, then 15ml of FeCl3 solution with a concentration of 0.3mol / L was added, and 4.5mL of pyrrole monomer solution (V 水 :V 吡咯 =1:1) was added dropwise under the condition of 0℃ ice water bath, and the reaction was continuously stirred for 12h; finally, it was washed with deionized water and ethanol, and vacuum freeze-dried, to obtain the ion sieve for selective extraction of lithium.

[0075] The ion sieve for selective extraction of lithium prepared in this example includes a lithium ion sieve substrate and an external coating of a poly-pyrrole coating layer doped with 4.59wt% carbon nanotubes; the particle size D50 is 6μm, and the particle size distribution width (D90-D10) / D50 is 1.13.

[0076] 2) Preparation of ion-sieve electrode for selective lithium extraction:

[0077] The selective lithium extraction ion-sieve and PVDF were mixed uniformly, and the mixture was added to NMP to form a slurry, with a mass ratio of selective lithium extraction ion-sieve, PVDF and NMP being 1:0.125:1. The slurry was coated on a 10x10 cm titanium mesh, with a controlled coating density of 0.1 g / cm 2 , and then the selective lithium extraction ion-sieve electrode was prepared after being kept at 110°C for 12 h, vacuum drying and cooling.

[0078] 3) Electrochemical lithium extraction method using the above selective lithium extraction ion-sieve electrode in brine:

[0079] The experimental device was a diaphragm electrolytic cell, which was divided into a brine chamber and a lithium-rich chamber by an anion exchange membrane. The selective lithium extraction ion-sieve electrode was placed in the brine chamber, and the activated carbon electrode was placed in the lithium-rich chamber.

[0080] 2 L of simulated salt lake brine containing 300 mg / L of Li + and 9000 mg / L of Mg 2+ was added to the brine chamber, and 2 L of 5 g / L KCl aqueous solution was added to the lithium-rich chamber.

[0081] The selective lithium extraction ion-sieve electrode was used as the cathode, and the activated carbon electrode was used as the anode. A voltage of 0.8 V was applied between the two electrodes to perform the electrochemical lithium extraction reaction at 25°C. Lithium ions in the brine were inserted into the ion-sieve electrode, and the reaction was maintained for 6 h. After the reaction, the concentration of Li + in the brine chamber was 56.2 mg / L, and the concentration of Mg 2+ was 8997 mg / L. The adsorption capacity of the selective lithium extraction ion-sieve for Li + was 48.76 mg / g, and the average current density was 31.38 A / m 2 . The adsorption capacity of the selective lithium extraction ion-sieve for Mg 2+ was 0.6 mg / g, and the lithium ion selectivity was 98.78%.

[0082] After the electrochemical lithium extraction reaction was completed, the positions of the selective lithium extraction ion-sieve electrode and the counter electrode were exchanged. A voltage of 0.8 V was applied between the two electrodes to perform the lithium extraction reaction at 25°C. The reaction was maintained for 6 h, and lithium ions were extracted from the ion-sieve. At this time, the concentration of Li + in the lithium-rich chamber was 240.6 mg / L, the lithium extraction rate was 98.7%, and the average current density was 30.97 A / m 2 . Thus, lithium enrichment can be achieved in the lithium-rich chamber, and lithium ions can be extracted from the brine.

[0083] 4) After repeating 10 times according to the same operation as step 3), test the effect data: the ion sieve for selectively extracting lithium in the lithium extraction reaction has an adsorption capacity of 46.1 mg / g for Li + and a lithium stripping rate of 98.3%.

[0084] Example 2

[0085] 1) Preparation of ion sieve for selectively extracting lithium:

[0086] 20 g of Li3V2O5, 0.2 g of carbon nanotubes, and 0.6 g of sodium dodecyl sulfonate were added to 50 mL of deionized water and stirred until uniform, then 15 mL of FeCl3 solution with a concentration of 0.3 mol / L was added and stirred until uniform, 9 mL of pyrrole-3-carboxylic acid monomer solution (V 水 :V 吡咯 = 2:1) was added dropwise under the condition of 0°C ice water bath, and the reaction was continuously stirred for 14 h; finally, deionized water and ethanol were used for washing, and vacuum freeze drying was performed, to obtain the ion sieve for selectively extracting lithium.

[0087] The ion sieve for selectively extracting lithium prepared in this example includes lithium ion sieve Li3V2O5 substrate and an outer coated polypyrrole coating layer doped with 4.82 wt% carbon nanotubes, with a particle size of 8.7 μm and a particle size distribution width (D90-D10) / D50 of 0.9.

[0088] 2) Preparation of ion sieve electrode for selectively extracting lithium:

[0089] 1 g of ion sieve for selectively extracting lithium, graphite, and PVDF were mixed uniformly, and the mixture was added to NMP to form a slurry, with the mass ratio of ion sieve for selectively extracting lithium, graphite, PVDF, and NMP being 1:0.125:0.125:1, the slurry was coated on a 10×10 cm titanium mesh, and the coating density was controlled to be 0.1 g / m 2 , based on the ion sieve for selectively extracting lithium in the slurry, then the titanium mesh was incubated at 110°C for 12 h, vacuum dried, and cooled to obtain the ion sieve electrode for selectively extracting lithium.

[0090] 3) Electrochemical lithium extraction method using the ion sieve electrode for selectively extracting lithium in brine:

[0091] The experimental device was a diaphragm electrolytic cell, which was divided into a brine chamber and a lithium-rich chamber by an anion exchange membrane, the ion sieve electrode for selectively extracting lithium was placed in the brine chamber, and an activated carbon electrode was placed in the lithium-rich chamber.

[0092] 2 L of simulated salt lake brine containing 300 mg / L of Li+ Mg 2+ , the lithium-rich chamber was added with 2 L of KCl aqueous solution with a concentration of 5 g / L.

[0093] The selective lithium extraction ion-sieve electrode was used as the cathode, and the activated carbon electrode was used as the anode. A voltage of 1 V was applied between the two electrodes to perform the electrochemical lithium extraction reaction at 35°C. Lithium ions in the brine were inserted into the ion-sieve electrode. After 3.5 h, the Li + concentration in the brine chamber was 69.0 mg / L, and the Mg 2+ concentration was 8998.8 mg / L. The selective lithium extraction ion-sieve had an adsorption capacity of 46.2 mg / g for Li + , and the average current density was 51.0 A / m 2 . The adsorption capacity of the selective lithium extraction ion-sieve for Mg 2+ was 0.24 mg / g, and the lithium ion selectivity was 99.5%.

[0094] After the electrochemical lithium extraction reaction was completed, the positions of the selective lithium extraction ion-sieve electrode and the counter electrode were interchanged. A voltage of 1 V was applied between the two electrodes to perform the lithium extraction reaction at 35°C. After 3.5 h, the reaction was completed, and lithium ions were extracted from the ion-sieve. At this time, the Li + concentration in the lithium-rich chamber was 226.1 mg / L, the lithium extraction rate was 97.88%, and the average current density was 49.9 A / m 2 . Thus, lithium enrichment can be achieved in the lithium-rich chamber, and lithium ions can be extracted from the brine.

[0095] 4) After repeating the operation 10 times according to the same procedure as in step 3), the effect data were tested. The selective lithium extraction ion-sieve still had an adsorption capacity of 45.5 mg / g for Li + , and the lithium extraction rate still reached 97%.

[0096] Example 3

[0097] 1) Preparation of the selective lithium extraction ion-sieve:

[0098] According to the method of Example 1, the difference was that Li 3.25 Mo 0.75 VO5 was used instead of Li3V2O5 when preparing the selective lithium extraction ion-sieve. The other operations and conditions remained unchanged.

[0099] The selective lithium extraction ion-sieve prepared in this example included a lithium ion-sieve substrate and an external polypyrrole coating layer doped with 4.59 wt% carbon nanotubes. The particle size of the ion-sieve was 7.3 μm, and the particle size distribution width (D90-D10) / D50 was 0.84.

[0100] 2) The selective lithium extraction ion-sieve electrode was prepared from the above selective lithium extraction ion-sieve according to the same method as in Example 1.

[0101] 3) The selective lithium extraction ion-sieve electrode was used to extract lithium electrochemically from the brine according to the method of Example 1:

[0102] After the electrochemical lithium extraction reaction was maintained for 5 h, the Li + concentration in the brine chamber was 60.4 mg / L, the Mg 2+ concentration was 8997.4 mg / L; the selective lithium extraction ion-sieve had an adsorption capacity for Li + of 47.92 mg / g, and the average current density was 37.0 A / m 2 . The adsorption capacity of the selective lithium extraction ion-sieve for Mg 2+ was 0.52 mg / g, and the lithium ion selectivity was 98.9%.

[0103] After the lithium extraction reaction was maintained for 5 h, the Li + concentration in the lithium-rich chamber was 235.5 mg / L, the lithium extraction rate was 98.3%, and the average current density was 36.4 A / m 2 .

[0104] 4) The same operation as in step 3) was repeated 10 times, and the effect data were tested: the adsorption capacity of the selective lithium extraction ion-sieve for Li + was still 46.8 mg / g, and the lithium extraction rate was still 97%.

[0105] Example 4

[0106] 1) The selective lithium extraction ion-sieve was prepared:

[0107] 20 g of Li3V2O5, 0.1 g of graphene, and 0.7 g of sodium dodecyl sulfonate were added to 50 mL of deionized water and stirred until uniform, then 15 mL of a 0.3 mol / L FeCl3solution was added and stirred until uniform, and 4.5 mL of a 3-pyrrole-formaldehyde monomer solution (V 水 :V 吡咯 = 1:1) was added dropwise under an ice water bath at 0°C, and the reaction was continuously stirred for 12 h; finally, deionized water and ethanol were used for washing, and vacuum freeze-drying was performed, and the selective lithium extraction ion-sieve was finally obtained.

[0108] The selective lithium extraction ion-sieve prepared in this example included a lithium ion-sieve substrate and an outer polypyrrole coating layer doped with 3.71 wt% carbon nanotubes; the particle size D50 was 5.4 μm, and the particle size distribution width (D90-D10) / D50 was 1.06.

[0109] 2) Preparation of ion-sieve electrode for selective lithium extraction:

[0110] The selective lithium extraction ion-sieve and PVDF were mixed uniformly, and the mixture was added into NMP to form a slurry, wherein the selective lithium extraction ion-sieve, PVDF and NMP were in a mass ratio of 1:0.125:1, and the slurry was coated on a 10x10 cm titanium mesh at a coating density of 0.1 g / cm 2 , and then the selective lithium extraction ion-sieve electrode was prepared after being kept at 110°C for 12 h, vacuum drying and cooling.

[0111] 3) Electrochemical lithium extraction method using the above selective lithium extraction ion-sieve electrode in brine:

[0112] The experimental device was a diaphragm electrolytic cell, which was divided into a brine chamber and a lithium-rich chamber by an anion exchange membrane. The selective lithium extraction ion-sieve electrode was placed in the brine chamber, and the activated carbon electrode was placed in the lithium-rich chamber.

[0113] 2 L of simulated salt lake brine containing 300 mg / L of Li + and 9000 mg / L of Mg 2+ was added to the brine chamber, and 2 L of 5 g / L KCl aqueous solution was added to the lithium-rich chamber.

[0114] The selective lithium extraction ion-sieve electrode was used as the cathode, and the activated carbon electrode was used as the anode. A voltage of 0.8 V was applied between the two electrodes to perform the electrochemical lithium extraction reaction at 20°C, so that lithium ions in the brine were embedded in the ion-sieve electrode. After 5 h, the concentration of Li + in the brine chamber was 44.8 mg / L, the concentration of Mg 2+ was 8997 mg / L; the adsorption capacity of the selective lithium extraction ion-sieve for Li + was 51.04 mg / g, the average current density was 39.4 A / m 2 , and the adsorption capacity for Mg 2+ was 0.6 mg / g, with a lithium ion selectivity of 98.84%.

[0115] After the electrochemical lithium extraction reaction was completed, the positions of the selective lithium extraction ion-sieve electrode and the counter electrode were exchanged, a voltage of 0.8 V was applied between the two electrodes to perform the lithium extraction reaction at 20°C, and the reaction was completed after 5 h. Lithium ions were extracted from the ion-sieve electrode. At this time, the concentration of Li + in the lithium-rich chamber was 251.2 mg / L, the lithium extraction rate was 98.4%, and the average current density was 38.8 A / m 2 . Thus, lithium enrichment can be achieved in the lithium-rich chamber, and lithium ions can be extracted from the brine.

[0116] 4) After repeating the same operation as step 3) for 10 times, the effect data of the ion sieve for selectively extracting lithium in the lithium extraction reaction is tested: the adsorption amount of Li + is still 49.7 mg / g, and the lithium stripping rate is still 97.5%.

[0117] Example 5

[0118] 1) Preparation of the ion sieve for selectively extracting lithium:

[0119] Referring to the method of Example 1, the difference is that when the ion sieve for selectively extracting lithium is prepared, Li3Ni 0.1 is used instead of Li3V2O5, and 3-hydroxy pyrrole monomer is used instead of pyrrole monomer; other operations and conditions remain unchanged.

[0120] The ion sieve for selectively extracting lithium prepared in this example includes a lithium ion sieve substrate and an outer coated layer of poly-3-hydroxy pyrrole doped with 3.54 wt% carbon nanotubes; the ion sieve particle size is 9.1 pm, and the particle size distribution width (D90-D10) / D50 is 0.7.

[0121] 2) The ion sieve for selectively extracting lithium is prepared from the ion sieve for selectively extracting lithium according to the same method as in Example 1.

[0122] 3) Using the ion sieve for selectively extracting lithium, the method of Example 1 is referred to for electrochemical lithium extraction in brine:

[0123] After the electrochemical lithium extraction reaction is maintained for 4 h, the Li + concentration in the brine chamber is 49.7 mg / L, the Mg 2+ concentration is 8996.6 mg / L; the adsorption amount of Li + on the ion sieve for selectively extracting lithium is 50.06 mg / g, the average current density is 48.3 A / m 2 , the adsorption amount of Mg 2+ is 0.68 mg / g, and the lithium ion selectivity is 98.66%.

[0124] After the lithium stripping reaction is maintained for 4 h, the Li + concentration in the lithium-rich chamber is 246.2 mg / L, the lithium stripping rate is 98.4%, and the average current density is 47.5 A / m 2 .

[0125] 4) After repeating the same operation as step 3) for 10 times, the effect data of the ion sieve for selectively extracting lithium in the lithium extraction reaction is tested: the adsorption amount of Li + is still 49.1 mg / g, and the lithium stripping rate is still 97.6%.

[0126] Comparative Example 1

[0127] 1) Refer to the method of Example 1, except that step 1) of preparing lithium-selective ion sieve is omitted, and lithium ion sieve Li3V2O5 is directly used to prepare lithium-selective ion sieve electrode; other operations and conditions remain unchanged.

[0128] 2) Using the above lithium-selective ion sieve electrode, refer to the method of Example 1, lithium is extracted by electrochemistry in brine:

[0129] After 10 hours of electrochemical lithium extraction reaction, the Li + concentration in the brine chamber is 168 mg / L, the Mg 2+ concentration is 8989 mg / L; the adsorption amount of Li + on the lithium-selective ion sieve is 26.4 mg / g, and the average current density is 10.2 A / m 2 , the adsorption amount of Mg 2+ is 2.2 mg / g, and the lithium ion selectivity is 92.3%.

[0130] After 10 hours of lithium extraction reaction, the Li + concentration in the lithium-rich chamber is 115 mg / L, the lithium extraction rate is 87.1%, and the average current density is 8.88 A / m 2 .

[0131] 3) After repeating 10 times according to the same operation as step 2), test the effect data: the adsorption amount of Li + on the lithium-selective ion sieve in the lithium extraction reaction is 15.7 mg / g, and the lithium extraction rate is 79%.

[0132] Comparative Example 2

[0133] 1) Refer to the method of Example 1, except that when preparing the lithium-selective ion sieve, no conductive carbon material carbon nanotubes are added; other operations and conditions remain unchanged.

[0134] 2) According to the same method as Example 1, a lithium-selective ion sieve electrode is prepared from the above lithium-selective ion sieve.

[0135] 3) Using the above lithium-selective ion sieve electrode, refer to the method of Example 1, lithium is extracted by electrochemistry in brine:

[0136] After 8 hours of electrochemical lithium extraction reaction, the Li + concentration in the brine chamber is 63.1 mg / L, the Mg 2+ concentration is 8998.3 mg / L; the adsorption amount of Li +The adsorption capacity was 47.38 mg / g, and the average current density was 22.87 A / m. 2 , for Mg 2+ The adsorption capacity was 0.34 mg / g, and the lithium ion selectivity was 99.3%.

[0137] After the delithiation reaction was maintained for 8 hours, Li in the lithium-rich chamber + The concentration was 219.7 mg / L, the lithium extraction rate was 92.7%, and the average current density was 21.2 A / m. 2 .

[0138] 4) Repeat the same procedure as step 3) 10 times, then test the results: the ion sieve for selective lithium extraction in the lithium extraction reaction for Li + The adsorption capacity was 44.5 mg / g, and the lithium removal rate was 90.3%.

[0139] Comparative Example 3

[0140] 1) Preparation of ion sieves for selective lithium extraction: In 100 mL of polyether... Add 0.1g of carbon nanotubes and disperse and stir until homogeneous; disperse 20g of Li3V2O5 in 100mL of... In (MDI), the supernatant was then separated by centrifugation, and the lower particulate slurry was taken out for later use. The particulate slurry obtained by centrifugation was added to polyether and continuously stirred and foamed for 12 hours. Finally, it was washed with deionized water and ethanol, and then freeze-dried under vacuum to obtain an ion sieve for selective lithium extraction.

[0141] 2) Following the same method as in Example 1, an ion sieve electrode for selective lithium extraction was prepared from the above-mentioned ion sieve for selective lithium extraction.

[0142] 3) Using the ion sieve electrode for selective lithium extraction described above, lithium is extracted from brine electrochemically, referring to the method in Example 1:

[0143] After the electrochemical lithium extraction reaction was maintained for 8 hours, the Li in the brine chamber + The concentration was 107.7 mg / L, Mg 2+ The concentration was 8996 mg / L; the ion sieve for selective lithium extraction was used for Li... + The adsorption capacity was 38.46 mg / g, and the average current density was 18.57 A / m. 2 , for Mg 2+ The adsorption capacity was 0.8 mg / g, and the lithium ion selectivity was 98.0%.

[0144] After the delithiation reaction was maintained for 8 hours, Li in the lithium-rich chamber + The concentration was 178.1 mg / L, the lithium extraction rate was 92.6%, and the average current density was 17.2 A / m. 2 .

[0145] 4) After repeating 10 times according to the same operation as step 3), test the effect data: the ion sieve for selectively extracting lithium in the lithium extraction reaction has an adsorption capacity of 37.22 mg / g for Li + and a lithium stripping rate of 91.7%.

Claims

1. An ion sieve for selectively extracting lithium, characterized in that, It includes a lithium-ion sieve substrate and a conductive carbon-doped pyrrole polymer coating layer covering the outside of the lithium-ion sieve substrate; The lithium-ion sieve substrate is a lithium vanadium-based oxide with a disordered rock salt-type structure. The pyrrole polymer is selected from one or more of polypyrrole-3-carboxylic acid, polypyrrole-3-carboxaldehyde, and 3-hydroxypolypyrrole; The conductive carbon material is selected from one or more of carbon fiber, carbon nanotubes, and graphene. The ion sieve for selective lithium extraction has a particle size of 2-18 μm and a particle size distribution width (D90-D10) / D50 ≤ 1.

2.

2. The ion sieve for selective lithium extraction according to claim 1, characterized in that, In the conductive carbon-doped pyrrole polymer coating layer, the amount of conductive carbon material doped is 0.05-20 wt%; and / or The lithium-ion sieve substrate has the general formula Li x M a V y O z Wherein, 2.5≤x≤5, 0.8≤y≤2.5, 4.5≤z≤6, 0≤a≤1.2; M is selected from one or more of transition metals, alkaline earth metals, Al, and B; and / or The conductive carbon material is doped with a pyrrole-based polymer coating layer.

3. The ion sieve for selective lithium extraction according to claim 2, characterized in that, The conductive carbon material has a doping amount of 0.1-10 wt%.

4. The ion sieve for selective lithium extraction according to claim 2, characterized in that, The ion sieve for selective lithium extraction has a particle size of 3-15 μm.

5. The ion sieve for selective lithium extraction according to claim 4, characterized in that, The ion sieve for selectively extracting lithium has a particle size of 5-12 μm.

6. The ion sieve for selective lithium extraction according to claim 2, characterized in that, The ion sieve for selective lithium extraction has a particle size distribution width (D). 90 -D 10 ) / D 50 ≤0.

7.

7. The ion sieve for selective lithium extraction according to claim 2, characterized in that, The general formula Li x M a V y O z In the equation, 2.8≤x≤4.85, 0.8≤y≤2.2, 4.8≤z≤5.3, and 0≤a≤0.

8.

8. The ion sieve for selective lithium extraction according to claim 7, characterized in that, The general formula Li x M a V y O z In the equation, 2.8≤x≤4, 1.8≤y≤2.2, 4.8≤z≤5.1, and 0≤a≤0.

5.

9. The ion sieve for selective lithium extraction according to claim 2, characterized in that, M is selected from one or more of the elements Ni, Co, Mo, Cr, Ti, Mn, Zr, Al, Mg, W, Y, Nb, Ta, Sr, Ce, and B.

10. A method for preparing an ion sieve for selective lithium extraction according to any one of claims 1-9, characterized in that the step... include: The lithium ion sieve substrate, conductive carbon material, and anionic surfactant are added to a solvent and dispersed evenly. Then, an initiator and pyrrole polymer monomer are added to carry out a polymerization reaction. After washing with water, washing with alcohol, and drying, an ion sieve for selective lithium extraction is obtained. The pyrrole polymer monomer is selected from one or more of pyrrole, pyrrole-3-carboxylic acid, pyrrole-3-carboxaldehyde, and 3-hydroxypyrrole.

11. The preparation method according to claim 10, characterized in that, The anionic surfactant is selected from one or more of sodium dodecyl sulfonate and sodium dodecylbenzene sulfonate; and / or The solvent is selected from one or more of water or alcohols; and / or The initiator is selected from one or more of ferric chloride, potassium permanganate, hydrogen peroxide, and ammonium persulfate; and / or The mass ratio of the pyrrole polymer monomer to the conductive carbon material is 100:(0.05-20); and / or The mass ratio of the lithium-ion sieve substrate to the conductive carbon material and the anionic surfactant is 10:(0.02-0.5):(0.1-2); and / or The mass ratio of the lithium-ion sieve substrate to the solvent is 1:(1-10); and / or The molar ratio of the pyrrole polymer monomer to the initiator is (2-20):1; and / or The pyrrole polymer monomer is prepared as a solution before being added, wherein the volume ratio of the pyrrole polymer monomer to the solvent is 1:1-50. Wherein, the solvent for the pyrrole polymer monomer is selected from one or more of water or alcohols; and / or The polymerization reaction is carried out at a temperature ≤5℃; and / or The polymerization reaction takes 7-18 hours.

12. The preparation method according to claim 11, characterized in that, The solvent is selected from one or more of water and ethanol.

13. The preparation method according to claim 11, characterized in that, The mass ratio of the pyrrole polymer monomer to the conductive carbon material is 100:(0.1-10).

14. The preparation method according to claim 11, characterized in that, The mass ratio of the lithium-ion sieve substrate to the conductive carbon material and the anionic surfactant is 10:(0.04-0.2):(0.3-1).

15. The preparation method according to claim 11, characterized in that, The mass ratio of the lithium-ion sieve substrate to the solvent is 1:(1.5-5).

16. The preparation method according to claim 11, characterized in that, The molar ratio of the pyrrole polymer monomer to the initiator is (5-10):

1.

17. The preparation method according to claim 11, characterized in that, The solvent used for pyrrole polymer monomers is selected from one or more of water and ethanol.

18. The preparation method according to claim 11, characterized in that, The polymerization reaction is carried out at a temperature of 0-5℃.

19. The preparation method according to claim 11, characterized in that, The polymerization reaction is carried out under ice-water bath conditions.

20. The preparation method according to claim 11, characterized in that, The polymerization reaction takes 10-16 hours.

21. An ion sieve electrode for selective lithium extraction, characterized in that, This includes the ion sieve for selectively extracting lithium as described in any one of claims 1-9, or the ion sieve for selectively extracting lithium prepared by the method described in any one of claims 11-20.

22. A method for preparing the selective lithium extraction ion sieve electrode according to claim 21, characterized in that the step... include: The selective lithium extraction ion sieve and polyvinylidene fluoride were mixed evenly and added to N-methylpyrrolidone and stirred into a slurry. The slurry was coated on a titanium mesh and kept at 80-140℃ for 3-24 hours and then dried to obtain the selective lithium extraction ion sieve electrode.

23. The preparation method according to claim 22, characterized in that, Keep warm at 100-130℃ for 10-15 hours.

24. The preparation method according to claim 22, characterized in that, The mass ratio of the ion sieve for selective lithium extraction to polyvinylidene fluoride is 1:(0.03-0.2); and / or The mass ratio of the ion sieve for selective lithium extraction to N-methylpyrrolidone is 1:(0.7-1.2); and / or The slurry, using an ion sieve for selective lithium extraction, has a coating density of 0.05-0.5 g / cm³ on a titanium mesh. 2 ; and / or Optionally, a conductive agent is added to the slurry, the conductive agent being selected from one or more of graphite, graphene, carbon nanotubes, and reduced graphene oxide; and / or Optionally, a titanium mesh with a carbon-coated surface can be used.

25. The preparation method according to claim 24, characterized in that, The mass ratio of the ion sieve for selective lithium extraction to polyvinylidene fluoride is 1:(0.05-0.15).

26. The preparation method according to claim 24, characterized in that, The mass ratio of the ion sieve for selective lithium extraction to N-methylpyrrolidone is 1:(0.8-1.05).

27. The preparation method according to claim 24, characterized in that, The slurry, using an ion sieve for selective lithium extraction, has a coating density of 0.08-0.3 g / m² on a titanium mesh. 2 .

28. The use of the selective lithium extraction ion sieve electrode of claim 21 or the selective lithium extraction ion sieve electrode prepared by any one of claims 22-27 in lithium extraction from lithium-containing solutions.

29. The application according to claim 28, characterized in that, The selective lithium extraction ion sieve electrode is used for lithium extraction from salt lake brine.

30. The application according to claim 29, characterized in that, The selective lithium extraction ion sieve electrode is used in salt lake brines with a high magnesium-to-lithium ratio.

31. An electrochemical lithium extraction method, characterized in that, The method employs the selective lithium extraction ion sieve electrode of claim 21 or the selective lithium extraction ion sieve electrode prepared by any one of claims 22-27, and is carried out in a membrane electrolyzer, using an anion exchange membrane as the diaphragm of the electrolyzer to divide the electrolyzer into a brine chamber and a lithium-rich chamber. The steps include: 1) Place the selective lithium extraction ion sieve electrode in the brine chamber, place the counter electrode in the lithium-rich chamber, inject the lithium-containing solution into the brine chamber, and inject the KCl solution into the lithium-rich chamber. 2) Using the selective lithium extraction ion sieve electrode as the cathode and the counter electrode as the anode, an electrochemical lithium extraction reaction is carried out by passing an electric current, so that lithium ions in the lithium-containing solution are embedded in the ion sieve electrode. 3) After the electrochemical lithium extraction reaction is completed, the positions of the selective lithium extraction ion sieve electrode and the counter electrode are interchanged, and an electric current is passed through to carry out the delithiation reaction, thereby achieving lithium enrichment in the lithium-rich chamber and extracting lithium ions from the lithium-containing solution.

32. The electrochemical lithium extraction method according to claim 31, characterized in that, Step 1) The counter electrode is an activated carbon electrode, a graphite electrode; and / or Step 1) The KCl solution is an aqueous solution of KCl with a concentration of 2-50 g / L; and / or Step 2) describes an electrochemical lithium extraction reaction at a temperature of -10 to 50°C for 1 to 10 hours; and / or In step 2), the electrochemical lithium extraction reaction has an inter-electrode voltage of <1.3V. Step 3) describes a delithiation reaction at a temperature of -10 to 50°C for 1 to 10 hours; and / or In step 3), the delithiation reaction occurs with an inter-electrode voltage of <1.3V.

33. The electrochemical lithium extraction method according to claim 32, characterized in that, Step 1) The KCl solution is an aqueous solution of KCl with a concentration of 5-20 g / L.

34. The electrochemical lithium extraction method according to claim 32, characterized in that, The electrochemical lithium extraction reaction described in step 2) is carried out at a temperature of 0-35℃ for a time of 2-6 hours.

35. The electrochemical lithium extraction method according to claim 32, characterized in that, In step 2), the electrochemical lithium extraction reaction is carried out with an electrode voltage of 0.5-1V.

36. The electrochemical lithium extraction method according to claim 32, characterized in that, The delithiation reaction described in step 3) is carried out at a temperature of 0-35℃ for a time of 2-6 hours.

37. The electrochemical lithium extraction method according to claim 32, characterized in that, In step 3), the delithiation reaction occurs with an electrode voltage of 0.5-1V.