High performance lithium ion sieve granular adsorbent based on lattice engineering and its preparation and application

Abstract

This invention discloses a high-performance lithium-ion sieve particle adsorbent based on lattice engineering, its preparation method, and its application. The preparation method includes: thoroughly mixing and refining a lithium source, a titanium source and / or a manganese source, a doped metal oxide, and a first solvent; then performing solid-liquid separation and calcination to obtain a lattice-modified lithium-ion sieve precursor; acid eluting and delithiating the lattice-modified lithium-ion sieve precursor with a dilute acid solution to obtain modified adsorbent active powder; mixing the modified adsorbent active powder, a binder, a hydrophilic pore-forming agent, and a second solvent to form a composite slurry; performing wet granulation on the composite slurry to obtain spherical wet particle coarse product; and drying and activating the spherical wet particle coarse product to obtain a high-performance lithium-ion sieve particle adsorbent based on lattice engineering. The adsorbent of this invention has higher adsorption capacity, faster adsorption kinetics, better selectivity, and stronger cycle stability.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion sieve particle adsorbent technology, specifically relating to a high-performance lithium-ion sieve particle adsorbent based on lattice engineering, its preparation method, and its application. Background Technology

[0002] With the rapid development of new energy vehicles and energy storage industries, global demand for lithium resources has surged. Extracting lithium from salt lake brines, seawater, or geothermal brines has become a strategic direction due to the huge resource reserves, and the adsorption method is regarded as the technology with the greatest industrialization potential due to its high selectivity, environmental friendliness, and simplicity.

[0003] Titanium-based (H₂TiO₃, or HTO for short) and manganese-based (such as HMO and λ-MnO₂) lithium-ion sieve materials, due to their unique "ion memory effect," can selectively capture lithium ions from complex salt lake brines, and are considered the core materials with the greatest industrial potential in the adsorption method for lithium extraction. However, these materials face a fundamental intrinsic problem during recycling: H + / Li + Exchange-induced lattice strain.

[0004] Specifically, lithium-type precursors (such as Li₂TiO₃ or Li) 1.6 Mn 1.6 During the acid elution and delithiation of lithium (O4) to convert it into a hydrogen-form adsorbent (such as H2TiO3 or HMO), due to Li + (Ionic radius 0.76 Å) is affected by H, which has a smaller ionic radius. + Substitution leads to a significant shrinkage of the cell volume; however, during lithium ion adsorption, the cell volume expands again. This cyclical lattice strain not only disrupts the structural integrity of the material, causing lattice distortion, microcrack formation, and even structural collapse, but also disrupts ion diffusion pathways, becoming a key factor limiting adsorption kinetics and cycle stability.

[0005] To address this issue, researchers have attempted to control the stability of crystal structures through ion doping. For example, Zhang Guotai et al. systematically studied Al... 3+ Doping of Li 1.6 Mn 1.6 The effect of O4-type manganese-based ion sieves was found to be Al 3+ Doping can increase the degree of lattice disorder and suppress the Jahn-Teller effect in spinel structures, thereby enhancing the Li... + The structural stability during desorption / insertion was demonstrated, with the adsorption capacity remaining at 26.82 mg / g after four cycles, while the manganese dissolution rate decreased to 1.92%. Zaxi Cuo et al. further proposed a "valence state engineering" strategy, using Al... 3+ / Mg 2+ / Na +Doping modulates the oxidation state of manganese, increasing the average valence state of manganese to +3.38 and reducing Mn. 3+ The content effectively inhibited Jahn-Teller distortion and strengthened Mn-O bonds, resulting in a 26.4% increase in adsorption capacity and a 47% reduction in manganese dissolution loss.

[0006] Although the above-mentioned doping modification techniques have made significant progress in improving the structural stability of lithium-ion sieves, the following shortcomings still exist: (1) The doping target is singular and lacks active design for strain regulation: Existing doping strategies mainly focus on improving the degree of lattice disorder, suppressing the Jahn-Teller effect, or regulating the manganese valence state. In essence, they passively resist strain by enhancing structural rigidity. No technology has yet explicitly proposed to take active regulation of lattice strain amplitude as the direct target, that is, to pre-construct a "pre-shrinkage" structure in the material synthesis stage, thereby reducing the cell volume difference between lithium-type precursors and hydrogen-type products. (2) The intrinsic selection of doping elements lacks consideration of strain matching: Existing doping methods mostly select doping ions (such as Al) from the perspective of valence state regulation and suppressing manganese dissolution. 3+ Mg 2+ However, it did not systematically consider the matching relationship between the radius of the doping ion and the radius of the substituted ion, nor the quantitative impact of the change in MO bond energy after doping on the degree of lattice shrinkage. For example, Al 3+ The ionic radius (0.535 Å) is smaller than that of Mn. 4+ (0.53 Å) and Mn 3+ (0.645 Å), but existing studies have not clearly linked it to the strain regulation target of "pre-induced lattice contraction". (3) Disconnect between microstructure optimization and macro-forming process: Existing doping modification studies are mostly at the level of powder materials. Although the performance improvement has been verified under laboratory conditions, when the modified powder is further prepared into particulate adsorbents required for industrial applications, the pore blockage and active site embedding caused by the forming process (such as adding binders and granulation) are often difficult to transfer the performance advantages brought by atomic-scale doping to macro products without damage. (4) Lack of systematic understanding of the relationship between lattice strain and the "performance triangle": Existing technology has failed to regard lattice strain as the key physical hub connecting selectivity, kinetics and stability. Therefore, its solutions are mostly "treating the symptoms" and single performance optimization (such as only improving stability), which makes it difficult to achieve synergistic improvement of the three. Summary of the Invention

[0007] The main objective of this invention is to provide a high-performance lithium-ion sieve particle adsorbent based on lattice engineering, its preparation method and application, in order to overcome the shortcomings of the prior art.

[0008] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0009] This invention provides a method for preparing a high-performance lithium-ion sieve particle adsorbent based on lattice engineering, comprising:

[0010] A lithium source, titanium source and / or manganese source, doped metal oxide and first solvent are thoroughly mixed and refined, followed by solid-liquid separation and calcination to obtain a lattice-modified lithium-ion sieve precursor.

[0011] The lattice-modified lithium-ion sieve precursor was subjected to acid elution and lithium removal treatment with dilute acid solution to obtain modified adsorbent active powder.

[0012] The modified adsorbent active powder, binder, hydrophilic pore-forming agent and second solvent are mixed to form a composite slurry;

[0013] The composite slurry is subjected to molding treatment to obtain spherical wet coarse particles;

[0014] Furthermore, the spherical wet particle crude product is dried, then immersed in an activation medium for activation and pore-forming treatment, and then washed and dried to obtain a high-performance lithium-ion sieve particle adsorbent based on lattice engineering.

[0015] The present invention also provides a high-performance lithium-ion sieve particle adsorbent based on lattice engineering prepared by the aforementioned preparation method.

[0016] This invention also provides the application of the aforementioned high-performance lithium-ion sieve particle adsorbent based on lattice engineering in the extraction of lithium ions, rubidium / cesium ions, magnesium ions, or heavy metal ions from salt lake brine, seawater, geothermal lithium-containing brine, oil and gas field produced water, leachate from waste lithium batteries, or industrial lithium-containing wastewater.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] (1) Original innovation to break the "performance triangle": By introducing rational doping (such as Co) in the material synthesis stage 3+ The implementation of "lattice prestressing" design suppressed H at the atomic level. + / Li + The harmful volumetric strain during the exchange process simultaneously improves the material's selectivity, kinetics, and cycle stability, breaking through the performance bottleneck of traditional ion sieves;

[0019] (2) Optimized structure and efficient performance transfer: The unique particle structure of “surface enriched with active powder and internally constructed with hydrophilic channels” maximizes the retention of the intrinsic high activity of the modified powder and ensures the rapid mass transfer of liquid phase ions, thus transforming the design advantages at the atomic scale into the excellent adsorption performance of macroscopic particles without damage.

[0020] (3) Balancing strength and capacity: The internal skeleton is constructed using a high-strength polymer binder with low addition amount. Under the premise of ensuring the excellent mechanical strength and wear resistance of the particles, an extremely high active component loading (>75%) is achieved, which solves the problem of mutual restriction between capacity and strength during the molding process;

[0021] (4) The process of the present invention is highly adaptable and easy to industrialize: the method is simple and the conditions are mild. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the lithium adsorbent preparation steps in a typical embodiment of the present invention;

[0024] Figure 2 This is a picture of the finished lithium adsorbent material in Example 1 of the present invention;

[0025] Figure 3 This is a picture of the finished lithium adsorbent material in Example 2 of the present invention;

[0026] Figures 4a-4b These are SEM images of the modified adsorbent active powder and the finished adsorbent product in Example 1 of this invention;

[0027] Figure 5 This is a diagram showing the lattice changes before and after adsorption in a typical embodiment of the present invention;

[0028] Figure 6 These are the XRD patterns of LTO and HTO in Embodiment 1 and Comparative Example 1 of the present invention;

[0029] Figure 7 These are the XRD patterns of LTO in Embodiment 1 and Comparative Examples 1-2 of the present invention. Detailed Implementation

[0030] In view of the shortcomings of existing technologies, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. This invention proposes a strain engineering strategy with "lattice prestress" as the design objective, which rationally selects ions with ions smaller than Ti. 4+ / Mn 4+ And doped ions that can form stronger MO bonds (such as Co) 3+In the lithium precursor synthesis stage, lattice contraction is actively induced to build a rigid framework, suppressing cyclic strain from the source, thereby simultaneously improving selectivity, kinetics and cyclic stability, and transferring this atomic-scale design advantage to macroscopic particulate products without damage through an optimized wet granulation process.

[0031] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Terminology Explanation:

[0033] Lattice engineering: Metal atoms have a certain volume. During the adsorption / desorption of Li ions by manganese / titanium ion sieves (LT / MO-HT / MO), lattice expansion and contraction occur because Li atoms are larger than H atoms. This engineering pre-contracts LT / MO by doping with metal ions, so that the volume of the adsorbent cell remains almost unchanged before and after adsorption-desorption, thereby achieving a balance between high adsorption capacity, fast mass transfer rate, and long-term cycle stability of the adsorbent powder.

[0034] Unit cell volume: refers to the size of the three-dimensional space occupied by the smallest repeating unit in a crystal structure—the unit cell. It is one of the fundamental parameters describing the geometric characteristics of a crystal.

[0035] The unit cell volume directly reflects the density of atomic packing in space. For lithium-ion sieve materials, the change in unit cell volume is a key indicator for measuring structural strain during ion insertion / extraction.

[0036] Lattice size: Definition: Usually refers to the lattice constant, which is the fundamental length parameter describing the geometry of a unit cell. Different crystal systems require different numbers of lattice constants for description.

[0037] Physical significance of lattice size: The lattice size determines the equilibrium distance between atoms and the size of crystal channels, which directly affects the "sieving" selectivity of ion sieves and the diffusion energy barrier of ions in the lattice.

[0038] Cell volume is the integral result of lattice size in three-dimensional space. A small change in the lattice constants (a, b, c) will be amplified into a significant change in cell volume through the volume formula. In this invention, we achieve effective suppression of the magnitude of cell volume changes by precisely controlling the lattice size (especially by inducing contraction of the a-axis and / or c-axis through doping), thereby achieving a balance between high adsorption capacity, fast mass transfer rate, and long-term cycling stability of the adsorbent powder.

[0039] Specifically, as one aspect of the technical solution of this invention, a method for preparing a high-performance lithium-ion sieve particle adsorbent based on lattice engineering includes:

[0040] A lithium source, titanium source and / or manganese source, doped metal oxide and first solvent are thoroughly mixed and refined, followed by solid-liquid separation and calcination to obtain a lattice-modified lithium-ion sieve precursor.

[0041] The lattice-modified lithium-ion sieve precursor was subjected to acid elution and lithium removal treatment with dilute acid solution to obtain modified adsorbent active powder.

[0042] The modified adsorbent active powder, binder, hydrophilic pore-forming agent and second solvent are mixed to form a composite slurry;

[0043] The composite slurry is subjected to molding treatment to obtain spherical wet coarse particles;

[0044] Furthermore, the spherical wet particle crude product is dried, then immersed in an activation medium for activation and pore-forming treatment, and then washed and dried to obtain a high-performance lithium-ion sieve particle adsorbent based on lattice engineering.

[0045] In some preferred embodiments, the preparation method specifically includes:

[0046] The lithium source, titanium source and / or manganese source, doped metal oxide and first solvent are thoroughly mixed, and then the mixture is refined by ball milling, colloid milling or high-speed shear stirring for 2-6 hours to obtain a uniform refined slurry.

[0047] The homogenized and refined slurry was subjected to solid-liquid separation, and the obtained filter cake was pre-dried at 60~120℃. Then, it was calcined in air at 600~800℃ for 3~4h to obtain a lattice-modified lithium-ion sieve precursor.

[0048] Furthermore, the lattice-modified lithium-ion sieve precursor is stirred and acid-washed with a dilute acid solution at room temperature for 4-12 minutes, and then filtered, washed, and dried to obtain hydrogen-type ion sieve active powder with optimized crystal structure, namely the modified adsorbent active powder.

[0049] Furthermore, the lithium source includes any one or more combinations of Li2CO3, CH3COOLi, and LiOH, and is not limited thereto.

[0050] Furthermore, the radius of the metal ions in the doped metal oxide is smaller than the radius of the titanium ions and / or manganese ions;

[0051] Further, the titanium source includes any one or a combination of multiple types selected from metatitanic acid type, titanate type, layered titanate, titanium nanotubes / titanium nanowires, titanium-manganese composite oxide, titanium / aluminum composite oxide, and titanium / silicon composite oxide; wherein, the metatitanic acid type includes H2TiO3, and the titanate type includes Li4Ti5O. 12 The layered titanate comprises, but is not limited to, any one or a combination of Li2Ti3O7 and its derivatives, wherein the layered titanate includes K2Ti4O9 and / or Na2Ti3O7.

[0052] Furthermore, the titanium source includes, but is not limited to, H2TiO3.

[0053] Further, the manganese source includes any one or more of the following: spinel-type manganese oxide, layered manganese oxide, tunnel-structured manganese oxide, titanium-manganese composite oxide, manganese / aluminum composite oxide, and manganese / silicon composite oxide; wherein the spinel-type manganese oxide includes any one or more of the following: λ-MnO2, LiMn2O4, and their derivatives; and the layered manganese oxide includes LiMnO2 and / or Na... 0.55 Mn2O4·1.5H2O, wherein the tunnel structure manganese oxide includes Mg2MnO4 and / or ZnMn2O4, but is not limited thereto.

[0054] Furthermore, when using a titanium source, the doped metal oxide includes any one or more combinations of Co oxide, Al oxide, Ga oxide, Fe oxide, Cr oxide, Mg oxide, Ni oxide, and Zn oxide, and is not limited thereto.

[0055] Among them, titanium source (replacing Ti) 4+ Alternative dopant ions (0.605 Å):

[0056] Co 3+ (0.545 Å, preferred in this invention): can form stronger Co-O bonds, significantly inducing lattice contraction;

[0057] Al 3+ (0.535 Å): Smaller ionic radius, matching valence state, and can form stable Al-O bonds;

[0058] Ga 3+ (0.62 Å): Radius slightly larger than Ti 4+ However, it can form strong Ga-O bonds;

[0059] Fe 3+ (0.645 Å, high spin) / 0.55 Å (low spin): lattice contraction can be achieved by controlling the spin state;

[0060] Cr3+ (0.615 Å): Can form stable Cr-O bonds;

[0061] Mg 2+ (0.72 Å): Although the radius is slightly larger, the difference in valence state can produce a charge compensation effect, inducing lattice defect shrinkage;

[0062] Ni 2+ (0.69 Å), Zn 2+ (0.74 Å): Divalent ions can indirectly regulate the crystal lattice through the vacancy mechanism.

[0063] Furthermore, when using a manganese source, the doped metal oxide includes any one or more combinations of Co oxide, Al oxide, Zr oxide, Mg oxide, Ni oxide, and Ti oxide, and is not limited thereto.

[0064] Among them, manganese source (replacing Mn) 4+ 0.53 Å / Mn 3+ Al(0.645 Å) substitution dopant ions: 3+ (0.535 Å): Radius matching, effectively suppressing the Jahn-Teller effect;

[0065] Co 3+ (0.545 Å): Can enhance structural rigidity;

[0066] Ni 2+ (0.69 Å), Mg 2+ (0.72 Å): Adjustable average valence state of manganese;

[0067] Ti 4+ (0.605 Å): Can form a more stable titanium-oxygen framework;

[0068] Zr 4+ (0.72 Å): Large radius doping can produce local compressive strain.

[0069] The doping in this invention can be single-element doping, dual-element co-doping (combinations of Al-Co, Al-Mg, Co-Ni, etc., which can synergistically control lattice strain and electronic structure), multi-element gradient doping (using different doping elements or doping concentrations from the inside of the particle to the surface to form a gradient strain field), and vacancy doping (introducing cation vacancies or oxygen vacancies through non-stoichiometric design to indirectly induce lattice contraction).

[0070] Furthermore, the molar ratio of the lithium source, titanium source and / or manganese source to the doped metal oxide is 2:1:0.005~0.15.

[0071] Furthermore, the first solvent includes ethanol.

[0072] Furthermore, the temperature is increased to 600-800℃ at a rate of 2-5℃ / min.

[0073] Further, the dilute acid solution includes dilute hydrochloric acid solution and / or dilute sulfuric acid solution; the concentration of the dilute acid solution is 0.1~0.5 mol / L.

[0074] Furthermore, the modified adsorbent active powder includes doped H2TiO3 or HMnO.

[0075] In some preferred embodiments, the preparation method specifically includes:

[0076] The second solvent is heated to 50-80°C, and then the binder and hydrophilic pore-forming agent are added under stirring to form a uniform and transparent binder stock solution.

[0077] Furthermore, the modified adsorbent active powder is added to the binder stock solution and mixed evenly to form a composite slurry.

[0078] Furthermore, the mass ratio of the modified adsorbent active powder to the binder and the modified adsorbent active powder is 75~95:100.

[0079] Furthermore, the mass ratio of the binder to the binder and the modified adsorbent active powder is 5~25:100.

[0080] Furthermore, the mass ratio of the hydrophilic pore-forming agent to the binder is 1~10:100.

[0081] Furthermore, the adhesive includes organic polymer adhesives and / or inorganic adhesives;

[0082] The organic polymer binder includes any one or more combinations of fluorinated polymers, sulfone polymers, nitrile polymers, acrylic polymers, cellulose derivatives, vinyl alcohol polymers, polyimide (PI), polystyrene (PS), polyvinyl chloride (PVC), and polyvinylpyrrolidone (PVP).

[0083] The fluorinated polymer includes any one or more combinations of polyvinylidene fluoride (PVDF), polyethersulfone (PES), polysulfone (PSF), and polyacrylonitrile (PAN), preferably polyvinylidene fluoride;

[0084] The sulfone polymer includes any one or more combinations of polyethersulfone (PES), polysulfone (PSF), and polyphenylsulfone (PPSU), preferably polyethersulfone and / or polysulfone;

[0085] The nitrile polymers include polyacrylonitrile (PAN);

[0086] The acrylic polymers include any one or more combinations of polyacrylic acid (PAA), polymethyl methacrylate (PMMA), and acrylic copolymers.

[0087] The cellulose derivatives include any one or more combinations of sodium carboxymethyl cellulose (CMC), hydroxypropyl methyl cellulose (HPMC), ethyl cellulose (EC), and cellulose acetate (CA);

[0088] The vinyl alcohol-based polymers include any one or more combinations of polyvinyl alcohol (PVA, which requires the use of a crosslinking agent) and polyvinyl butyral (PVB).

[0089] The inorganic binder includes any one or more combinations of clay minerals, silicates, phosphates, and aluminates; wherein the clay minerals include any one or more combinations of bentonite, kaolin, montmorillonite, and attapulgite; the phosphates include any one or more combinations of aluminum dihydrogen phosphate and phosphate glass; and the aluminates include calcium aluminate cement, but are not limited thereto.

[0090] Furthermore, the hydrophilic pore-forming agent comprises a water-soluble polymer; preferably, the water-soluble polymer comprises any one or more combinations of polyvinyl alcohol (PVA), polyethylene glycol (PEG), polyacrylamide (PAM), polyvinylpyrrolidone (PVP), polyethylene oxide (PEO), polyacrylic acid (PAA), and their salts, but is not limited thereto.

[0091] Among them, polyethylene glycol (PEG, preferred in this invention): different molecular weights (200-20000) can be used;

[0092] Polyvinyl alcohol (PVA, preferred in this invention): different degrees of alcoholysis;

[0093] Polyacrylamide (PAM, preferred in this invention): anionic, cationic, and nonionic;

[0094] Polyvinylpyrrolidone (PVP): K15-K90 with different molecular weights;

[0095] Polyethylene oxide (PEO): a high molecular weight water-soluble polyether;

[0096] Polyacrylic acid (PAA) and its salts: sodium polyacrylate, etc.

[0097] Furthermore, the second solvent comprises a polar organic solvent; wherein the polar organic solvent comprises, but is not limited to, N-methylpyrrolidone and / or N,N-dimethylformamide.

[0098] In some preferred embodiments, the preparation method specifically includes: molding the composite slurry using at least one of the following methods: wet granulation, oil curing, compression molding, casting-crushing-sieving, 3D printing, and electrospinning / spray drying.

[0099] 1. Wet granulation

[0100] Extrusion rounding granulation: In a preferred embodiment of the present invention, the slurry is extruded into strips, cut, and then rounded into spheres;

[0101] Spray granulation: The slurry is atomized and sprayed into a hot air stream, and dried instantly to form spherical particles; Fluidized bed granulation: The slurry is sprayed into a fluidized bed and agglomerated and granulated in a fluidized state;

[0102] Agitation granulation: Powder and a small amount of liquid are added to a high-speed mixer, and agglomeration and granulation are carried out by agitation force;

[0103] Rotary granulation: The powder is placed on a rotating disc and sprayed with liquid binder to roll into balls;

[0104] 2. Oil-based curing method

[0105] Principle: The slurry is dropped into hot oil or curing liquid, and surface tension is used to form spheres and then cure them;

[0106] Suitable adhesives: sodium alginate (cured by dripping into CaCl2 solution), chitosan (cured by dripping into alkaline solution), polyvinyl alcohol (cured by boric acid crosslinking).

[0107] Advantages: It can produce particles with high sphericity and uniform particle size;

[0108] 3. Compression molding method

[0109] Dry tableting: The powder is mixed with a small amount of dry powder binder and then directly compressed into tablets;

[0110] Wet molding: The slurry is filled into the mold, pressed, and then demolded.

[0111] Isostatic pressing: Powder is loaded into a mold and uniformly pressed in a high-pressure liquid medium to form the powder.

[0112] 4. Casting-crushing-screening method

[0113] Process flow: The slurry is cast into a film or block, dried, crushed, and screened to obtain irregular particles;

[0114] Advantages: Simple process, no special granulation equipment required;

[0115] Applicable scenarios: Applications where particle shape requirements are not high;

[0116] 5. 3D printing molding

[0117] Direct writing of slurry: Using composite slurry as "ink", it is directly written through 3D printing, which can precisely control the particle shape and internal channel structure;

[0118] Photopolymer 3D printing: Active powder is dispersed in photosensitive resin and formed layer by layer through photopolymerization;

[0119] 6. Electrospinning / Spray drying

[0120] Electrospinning: Prepare nanofiber membranes, and then cut them into particles after post-processing to create pores;

[0121] Spray drying: The slurry is atomized and then dried instantly to directly obtain microspheres.

[0122] In some preferred embodiments, the preparation method specifically includes: using a wet granulation device to perform wet granulation molding treatment on the composite slurry to obtain spherical wet granules.

[0123] In some preferred embodiments, the preparation method specifically includes: drying the spherical wet particle crude product, then immersing the obtained material in an activation medium at 0~90℃ for activation and pore-forming treatment, then washing and drying at 60~100℃ to obtain a high-performance lithium-ion sieve particle adsorbent based on lattice engineering.

[0124] Furthermore, the activation medium includes any one or more combinations of water, dilute acid solution, dilute alkali solution, alcohol-water mixture, and hot water, wherein the dilute acid solution includes 0.01 mol / L dilute hydrochloric acid.

[0125] Furthermore, the temperature of the activation pore-forming treatment is 20~60℃.

[0126] Furthermore, the temperature of the activation pore-forming treatment is 4~20℃.

[0127] Furthermore, the temperature of the activation pore-forming treatment is 60~90℃.

[0128] Furthermore, the soaking time is 0.5 to 2 hours.

[0129] The activation and pore-forming treatment in this invention can be carried out in the following ways: static soaking: preferred in this invention; dynamic soaking: soaking under stirring or shaking conditions to accelerate mass transfer; ultrasonic-assisted activation: using ultrasound to accelerate the dissolution of the pore-forming agent and the connection of pores; continuous flow activation: packing the particles into a column so that the activation medium flows continuously through the particle bed; vacuum impregnation: first evacuating the air from the particles, and then introducing the activation medium to promote the connection of pores.

[0130] In some preferred embodiments, the preparation method of the high-performance lithium-ion sieve particle adsorbent based on lattice engineering includes:

[0131] (1) Preparation of lattice engineering modified adsorbent powder

[0132] Lithium source, titanium source (or manganese source) and specific doped metal oxide (such as Co) are used to make lithium source, titanium source (or manganese source) and specific doped metal oxide (such as Co). 3+ Al 3+ Oxides such as Mg²⁺ are weighed according to stoichiometric ratio and added to deionized water or an organic solvent to form a homogeneous slurry. The slurry is thoroughly mixed and refined by ball milling, colloid milling, or high-speed stirring. Solid-liquid separation is then performed, and the resulting wet material is calcined in air at 600-800℃ for 3-4 hours to synthesize a lattice-modified lithium-ion sieve precursor (such as doped Li₂TiO₃ or LiMnO₂). Finally, the precursor is acid-washed with a dilute acid solution (such as 0.1-0.5 mol / L HCl) to remove lithium, yielding a hydrogen-type ion sieve active powder with a "lattice prestressed" structure (such as doped H₂TiO₃ or HMnO), i.e., modified adsorbent active powder.

[0133] (2) Preparation of composite bonding grout

[0134] The modified adsorbent active powder, organic polymer binder and hydrophilic pore-forming agent obtained in step (1) are dissolved or dispersed together in a polar organic solvent (such as N-methylpyrrolidone, N,N-dimethylformamide) in a specific ratio and stirred to form a uniform and plastic composite slurry.

[0135] The mass ratio of each component is as follows:

[0136] Modified adsorbent active powder: accounting for 75% to 95% of the total solid mass (powder + binder).

[0137] Organic polymer binders: accounting for 5% to 20% of the total solid mass.

[0138] Hydrophilic pore-forming agent: The amount added is 1% to 10% of the adhesive mass.

[0139] (3) Wet granulation molding

[0140] The above-mentioned composite slurry is granulated by extrusion to directly form spherical wet granules.

[0141] (4) Post-treatment and activation

[0142] a) Activation and pore formation: Immerse the dried particles in deionized water or dilute acid solution for 0.5-2 hours. During this process, the hydrophilic pore-forming agent and solvent are dissolved and eluted, leaving three-dimensional interconnected hydrophilic micropore channels inside the particles.

[0143] b) Final drying: The activated particles are washed until neutral and dried again to obtain a high-performance lithium-ion sieve particle adsorbent based on lattice engineering.

[0144] In some more specific embodiments, the preparation of high-performance lithium-ion sieve particle adsorbents based on lattice engineering in this invention mainly includes four core steps: preparation of lattice-engineered modified powder, formulation of composite binder slurry, wet granulation, and post-treatment and activation. A schematic diagram of the process flow is shown below. Figure 1 As shown.

[0145] (1) Preparation of lattice engineering modified adsorbent powder

[0146] This step forms the basis of the performance of this invention and aims to synthesize a precursor with a "lattice prestressed" structure. Specifically, it includes:

[0147] Slurry preparation: Accurately weigh the lithium source (e.g., Li₂CO₃), titanium source (e.g., TiO₂), or manganese source (e.g., MnO₂) according to the designed stoichiometric ratio, as well as the specific doped metal oxide (preferably Co). 3+ Oxides). Add them to deionized water or organic solvent, and stir by ball milling, colloid milling or high-speed shearing for 2-6 hours to form a highly uniform and fine slurry.

[0148] Calcination synthesis: The above slurry is subjected to solid-liquid separation. The resulting filter cake is pre-dried at 60-120℃ and then placed in a muffle furnace. The temperature is increased to 600-800℃ at a rate of 2-5℃ / min under air atmosphere and held for 3-4 hours. After programmed cooling, a lattice-modified lithium-ion sieve precursor (such as Co) is obtained. 3+ Doped Li₂TiO₃).

[0149] Acid washing and activation: The precursor is acid-washed with a 0.1-0.5 mol / L dilute hydrochloric acid solution at room temperature for 4-12 hours with stirring to completely remove lithium ions from the structure. After filtration and washing until neutral, and drying, hydrogen-type ion sieve active powder with optimized crystal structure (such as Co) is obtained. 3+ Doped H2TiO3, i.e., modified adsorbent active powder. Due to the pre-designed lattice contraction (synchronous reduction of cell parameters a-axis and c-axis) and strong bonding (Co-O bond), this powder has excellent strain tolerance.

[0150] (2) Preparation of composite bonding grout

[0151] This step aims to transform high-performance powders into formable materials.

[0152] Weigh an appropriate amount of polar organic solvent (such as N-methylpyrrolidone, NMP) and heat it to 50–80°C. While stirring, add the organic polymer binder and hydrophilic pore-forming agent, and continue stirring until completely dissolved to obtain a homogeneous and transparent binder stock solution.

[0153] Add the modified active powder obtained in step (1) to the above-mentioned stock solution, and mix it by mechanical stirring, kneading or directly in the extruder barrel for 0.5-2 hours to form a composite slurry with uniform composition and good plasticity.

[0154] Key proportions: active powder accounts for 75% to 95% of the total solid mass (powder + binder); binder accounts for 5% to 20% of the total solid mass; hydrophilic pore-forming agent is added at 1% to 10% of the binder mass.

[0155] (3) Wet granulation molding

[0156] The composite slurry was directly granulated into spherical adsorbents using a wet granulation machine.

[0157] (4) Post-treatment and activation

[0158] This step aims to solidify the structure and create mass transfer channels.

[0159] Activation and pore formation: Immerse the dried particles in deionized water or dilute acid solution (such as 0.01 M HCl) at a constant temperature of 20-60℃ for 0.5-2 hours. During this process, the hydrophilic pore-forming agent and residual trace solvent are dissolved and eluted, thereby forming a three-dimensional interconnected microporous channel network with a hydrophilic surface in situ inside the particles.

[0160] Final treatment: The activated particles are thoroughly washed with deionized water until the filtrate is neutral, and then dried at 60-100℃ to constant weight to obtain the final high-performance lithium-ion sieve particle adsorbent based on lattice engineering.

[0161] The lattice changes of the high-performance lithium-ion sieve particle adsorbent before and after adsorption in this invention are shown in the following diagram. Figure 5 As shown.

[0162] Another aspect of this invention provides a high-performance lithium-ion sieve particle adsorbent based on lattice engineering, prepared by the aforementioned method. Further, but not limited thereto.

[0163] Another aspect of this invention provides the application of the aforementioned high-performance lithium-ion sieve particle adsorbent based on lattice engineering in the extraction of lithium ions, rubidium / cesium ions, magnesium ions, or heavy metal ions from salt lake brine, seawater, geothermal lithium-containing brine, oil and gas field produced water, leachate from waste lithium batteries, or industrial lithium-containing wastewater.

[0164] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. This embodiment is implemented on the premise of the technical solution of the invention, and provides detailed implementation methods and specific operation processes. However, the protection scope of the present invention is not limited to the following embodiments.

[0165] Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0166] Example 1

[0167] Li₂CO₃, TiO₂·H₂O, and Co₂O₃ were mixed with 2 times their mass volume of ethanol in a ball mill at a molar ratio of 1:1:0.04. After 2 hours of homogeneous mixing, the mixture was filtered, dried in a constant temperature oven at 60°C for 2 hours, and then calcined in a muffle furnace at 700°C for 3 hours at a heating rate of 5°C / min. This yielded pre-delithiation modified active powder (LTO), as shown by XRD. Figure 6 , 7 As shown in the figure. After delithiation with 0.2 mol / L HCl at a solid-liquid ratio of 10 g / L, the modified adsorbent active powder (HTO) was obtained. XRD pattern as shown in the figure. Figure 6 As shown; modified adsorbent active powder, such as Figure 4a As shown;

[0168] Polysulfone was dissolved in N-methylpyrrolidone solution and kept at 50°C for 3 hours to obtain a binder (1g of polysulfone was used in 4ml of solution). The modified adsorbent active powder, binder and NMP solution were mixed evenly in a wet granulator to obtain a granular adsorbent precursor (the ratio of adsorbent powder to binder polysulfone was 85:15. The role of NMP is to wet the material. NMP will dissolve in water and will not affect the component ratio in the adsorbent).

[0169] The particulate adsorbent precursor was activated in water, NMP was dissolved, and the product was dried at 60°C for 3 hours to obtain the final adsorbent product. The final adsorbent product is shown below. Figure 2 As shown, the particle SEM image is as follows. Figure 4b .

[0170] Example 2

[0171] The proportions are the same as in Example 1, except that the binder is a neutral silica solution (30%). Specifically, the modified adsorbent active powder and silica sol (SiO2 content 10%) are poured into an extruder and mixed evenly, with an appropriate amount of water added for wetting. The mixed slurry is first extruded and then rolled into a spherical shape on a spherical rolling machine. The finished adsorbent product is as follows: Figure 3 As shown.

[0172] Comparative Example 1

[0173] The conditions were the same as in Example 1, the only difference being that Co was not performed. 3+ Doping; the XRD pattern of the prepared LTO is as follows: Figure 6 , 7 As shown, the XRD of HTO is as follows Figure 6 As shown.

[0174] Comparative Example 2

[0175] The method is the same as in Example 1, except that the doping ion used is Co. 2+ The XRD pattern of the prepared LTO is as follows: Figure 7 As shown.

[0176] Adsorption experiment:

[0177] The brine used in the adsorption experiments is shown in Table 1. In the static experiment, 0.5-2 g of the adsorbent product prepared in the above examples and comparative examples was added to 1000 mL of brine and stirred continuously. After 2 hours, the adsorption capacity was measured. In the dynamic experiment, after adding the adsorbent prepared in the above examples and comparative examples to the adsorption column, oilfield brine was introduced into the lower section of the adsorption column and exited from the upper outlet. The ion concentration of the liquid in the outlet was measured at regular intervals.

[0178] Table 1

[0179] The adsorption capacity A is calculated using the following formula: A = (C0 - C1)V / 1000, where C0 is the initial ion concentration in the solution, C1 is the ion concentration in the solution after adsorption, and V is the solution volume.

[0180] (1) Place 0.5g of the adsorbent from Example 1 and Comparative Example 1 in a flask and add 1L of brine from Table 1 for adsorption at room temperature for 3h. Test the performance parameters of the adsorbent powder, as shown in Table 2. The desorption is to dilute hydrochloric acid with a solid-liquid ratio of 10g / L and 0.2mol / L.

[0181] Table 2

[0182] (2) Place 1g of the adsorbent product from Example 1 into a flask and add 1L of the brine in Table 1 for adsorption at room temperature for 2 hours. Cycle 10 times and test its adsorption stability, as shown in Table 3.

[0183] Table 3

[0184] As shown in the table above, the particulate adsorbent prepared in this invention exhibits excellent overall performance in 10 cycles of testing. It demonstrates good adsorption performance (high capacity and strong cycle stability), good selectivity (strong lithium-ion recognition ability), and a fast adsorption rate. Therefore, this invention successfully integrates high performance, high selectivity, and rapid kinetics, providing a reliable solution for the efficient extraction of lithium.

[0185] As can be seen from the above, the present invention has the following advantages:

[0186] (1) A novel "lattice prestressing" strategy is proposed to suppress cyclic strain at its source: Existing doping technologies mainly passively resist strain by increasing lattice disorder or controlling element valence states, lacking a clear design objective for actively controlling lattice strain. This invention proposes for the first time a strain engineering strategy centered on "lattice prestressing," which involves screening ions with radii smaller than Ti. 4+ / Mn 4+ And doped ions that can form stronger MO bonds (such as Co) 3+ 0.545 Å replaced Ti 4+ (0.605 Å), lattice shrinkage is induced in advance during the lithium-type precursor synthesis stage to reduce the cell volume difference between the lithium-type precursor and the hydrogen-type product, thus suppressing harmful lattice strain during cycling from the source. This design enables the material to withstand subsequent H... + / Li + The magnitude of structural changes during the exchange process is significantly reduced, laying a structural foundation for simultaneously improving selectivity, dynamics, and stability.

[0187] (2) Solving the "performance triangle" problem and achieving synergistic improvement in selectivity, kinetics and stability: Existing technologies are constrained by the "impossible triangle" of "high selectivity, fast kinetics and long-cycle stability are difficult to achieve simultaneously," often resulting in one aspect being sacrificed for another. This invention constructs a rigid and stable ion diffusion channel through "lattice prestressing" design, enabling synergistic optimization of the three properties:

[0188] Higher adsorption capacity: Example 1 (Co doped) has an adsorption capacity of 26.52 mg / g, which is significantly higher than the 21.99 mg / g of Comparative Example 1 (undoped), proving that the lattice prestress design retains more effective adsorption sites;

[0189] Faster adsorption kinetics: Example 1 achieved 90% adsorption performance in just 1 hour, while Comparative Example 1 required 4 hours, indicating that suppressing lattice strain is beneficial for maintaining fast ion diffusion channels;

[0190] Better selectivity: Na in the eluent of Example 1 + The concentration was only 5.1 mg / L, far lower than the 49.8 mg / L of Comparative Example 1, proving that the crystal sieve channels remained more intact after circulation;

[0191] Enhanced cycle stability: Example 2 (doping + granulation) showed an adsorption capacity of 19-20 mg / g after 10 cycles with almost no decay, demonstrating excellent cycle life.

[0192] (3) Atomic-scale design advantages are seamlessly transferred to macroscopic particle products: In existing technologies, doping modification is mostly limited to the powder level. Subsequent molding processes (such as adding binders for granulation) often lead to pore blockage and embedding of active sites, making it impossible to realize the advantages of microscopic performance. This invention uses an optimized wet granulation process to construct the particle skeleton with a high-strength polymer binder (accounting for 5%-20% of the total solids) and adds a water-soluble pore-forming agent (accounting for 1%-10% of the binder mass). In the post-processing stage, the pore-forming agent is washed away by soaking in water or dilute acid, forming three-dimensional interconnected hydrophilic channels in situ. This design allows brine to quickly contact all internal active sites, seamlessly converting the ion diffusion potential promoted by lattice pre-shrinkage into the excellent mass transfer rate of macroscopic particles, realizing the unity from atomic-scale design to macroscopic engineering performance;

[0193] (4) Breaking through the trade-off between "performance and strength" to achieve a balance between high capacity and high strength: In traditional molding processes, increasing the amount of binder can improve particle strength, but it will clog the pores and cause the adsorption capacity to decrease by 20%-40%; reducing the binder will make the particles easy to break. This invention achieves an extremely high loading rate of active components by synergistically designing a low addition amount (5%-20%) of high-strength polymer binder and a high active powder loading amount (75%-95%), while ensuring the excellent mechanical strength and wear resistance of the particles, thus solving the engineering problem of the mutual constraint between capacity and strength in the molding process;

[0194] (5) Simple process, strong adaptability, and easy to industrialize and promote: The method described in this invention has a simple process and mild conditions. The raw materials involved are all conventional chemical raw materials, requiring no special equipment and suitable for continuous large-scale production. At the same time, the "lattice prestress" design strategy has universality and can be extended to other titanium-based and manganese-based ion sieve materials, providing a complete solution for developing a new generation of efficient, stable, and engineerable lithium extraction adsorbents.

[0195] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0196] It should be understood that the technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made to the technical solutions of the present invention without departing from the spirit and scope of the claims are within the scope of protection of the present invention.

Claims

1. A method for preparing a high-performance lithium-ion sieve particle adsorbent based on lattice engineering, characterized in that, include: A lithium source, titanium source and / or manganese source, doped metal oxide and first solvent are thoroughly mixed and refined, followed by solid-liquid separation and calcination to obtain a lattice-modified lithium-ion sieve precursor. The lattice-modified lithium-ion sieve precursor was subjected to acid elution and lithium removal treatment with dilute acid solution to obtain modified adsorbent active powder. The modified adsorbent active powder, binder, hydrophilic pore-forming agent and second solvent are mixed to form a composite slurry; The composite slurry is subjected to molding treatment to obtain spherical wet coarse particles; Furthermore, the spherical wet particle crude product is dried, then immersed in an activation medium for activation and pore-forming treatment, and then washed and dried to obtain a high-performance lithium-ion sieve particle adsorbent based on lattice engineering.

2. The preparation method according to claim 1, characterized in that, Specifically, it includes: The lithium source, titanium source and / or manganese source, doped metal oxide and first solvent are thoroughly mixed, and then the mixture is refined by ball milling, colloid milling or high-speed shear stirring for 2-6 hours to obtain a uniform refined slurry. The homogenized and refined slurry was subjected to solid-liquid separation, and the obtained filter cake was pre-dried at 60~120℃. Then, it was calcined in air at 600~800℃ for 3~4h to obtain a lattice-modified lithium-ion sieve precursor. Furthermore, the lattice-modified lithium-ion sieve precursor is stirred and acid-washed with a dilute acid solution at room temperature for 4-12 minutes, and then filtered, washed, and dried to obtain hydrogen-type ion sieve active powder with optimized crystal structure, namely the modified adsorbent active powder.

3. The preparation method according to claim 2, characterized in that: The lithium source includes any one or a combination of more than one of Li2CO3, CH3COOLi, and LiOH; And / or, the radius of the metal ion in the doped metal oxide is smaller than the radius of the titanium ion and / or manganese ion; And / or, the titanium source includes any one or a combination of multiple types selected from metatitanic acid type, titanate type, layered titanate, titanium nanotubes / titanium nanowires, titanium-manganese composite oxide, titanium / aluminum composite oxide, and titanium / silicon composite oxide; wherein, the metatitanic acid type includes H2TiO3, and the titanate type includes Li4Ti5O 12 The titanium source comprises any one or more of Li2Ti3O7 and its derivatives, wherein the layered titanate includes K2Ti4O9 and / or Na2Ti3O7; preferably, the titanium source comprises H2TiO3. And / or, the manganese source includes any one or more of the following: spinel-type manganese oxide, layered manganese oxide, tunnel-structured manganese oxide, titanium-manganese composite oxide, manganese / aluminum composite oxide, and manganese / silicon composite oxide; wherein, the spinel-type manganese oxide includes any one or more of the following: λ-MnO2, LiMn2O4, and their derivatives; and the layered manganese oxide includes LiMnO2 and / or Na... 0.55 Mn2O4·1.5H2O, wherein the tunnel structure manganese oxide includes Mg2MnO4 and / or ZnMn2O4; And / or, when a titanium source is used, the doped metal oxide includes any one or more combinations of Co oxide, Al oxide, Ga oxide, Fe oxide, Cr oxide, Mg oxide, Ni oxide, and Zn oxide; And / or, when a manganese source is used, the doped metal oxide includes any one or more combinations of Co oxide, Al oxide, Zr oxide, Mg oxide, Ni oxide, and Ti oxide; And / or, the molar ratio of the lithium source, titanium source and / or manganese source to the doped metal oxide is 2:1:0.005~0.15; And / or, the first solvent includes ethanol; And / or, raise the temperature to 600-800℃ at a rate of 2-5℃ / min; And / or, the dilute acid solution includes dilute hydrochloric acid solution and / or dilute sulfuric acid solution; the concentration of the dilute acid solution is 0.1~0.5 mol / L; And / or, the modified adsorbent active powder includes doped H2TiO3 or HMnO.

4. The preparation method according to claim 1, characterized in that, Specifically, it includes: The second solvent is heated to 50-80°C, and then the binder and hydrophilic pore-forming agent are added under stirring to form a uniform and transparent binder stock solution. Furthermore, the modified adsorbent active powder is added to the binder stock solution and mixed evenly to form a composite slurry.

5. The preparation method according to claim 4, characterized in that: The mass ratio of the modified adsorbent active powder to the binder and the modified adsorbent active powder is 75~95:

100. And / or, the mass ratio of the binder to the sum of the binder and the modified adsorbent active powder is 5~25:100; And / or, the mass ratio of the hydrophilic pore-forming agent to the binder is 1~10:100; And / or, the adhesive includes organic polymer adhesives and / or inorganic adhesives; The organic polymer binder includes any one or more combinations of fluorinated polymers, sulfone polymers, nitrile polymers, acrylic polymers, cellulose derivatives, vinyl alcohol polymers, polyimide, polystyrene, polyvinyl chloride, and polyvinylpyrrolidone. The fluorinated polymers include any one or more combinations of polyvinylidene fluoride, polyethersulfone, polysulfone, and polyacrylonitrile, preferably polyvinylidene fluoride; The sulfone polymer includes any one or more combinations of polyethersulfone, polysulfone, and polyphenylsulfone, preferably polyethersulfone and / or polysulfone; The nitrile polymer includes polyacrylonitrile; The acrylic polymer includes any one or more combinations of polyacrylic acid, polymethyl methacrylate, and acrylic copolymers; The cellulose derivatives include any one or more combinations of sodium carboxymethyl cellulose, hydroxypropyl methyl cellulose, ethyl cellulose, and cellulose acetate; The vinyl alcohol-based polymers include any one or more combinations of polyvinyl alcohol and polyvinyl butyral. The inorganic binder comprises any one or more combinations of clay minerals, silicates, phosphates, and aluminates; wherein the clay minerals include any one or more combinations of bentonite, kaolin, montmorillonite, and attapulgite; the phosphates include any one or more combinations of aluminum dihydrogen phosphate and phosphate glass; and the aluminates include calcium aluminate cement. And / or, the hydrophilic pore-forming agent comprises a water-soluble polymer; preferably, the water-soluble polymer comprises any one or more combinations of polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, polyethylene oxide, polyacrylic acid, and their salts. And / or, the second solvent comprises a polar organic solvent; preferably, the polar organic solvent comprises N-methylpyrrolidone and / or N,N-dimethylformamide.

6. The preparation method according to claim 1, characterized in that, Specifically, it includes: The composite slurry is shaped using at least one of the following methods: wet granulation, oil curing, compression molding, casting-crushing-screening, 3D printing, and electrospinning / spray drying. And / or, the composite slurry is subjected to wet granulation molding process using a wet granulation device to obtain spherical wet granules.

7. The preparation method according to claim 1, characterized in that, Specifically, it includes: The spherical wet particles are dried, and then the obtained material is immersed in an activation medium at 0~90℃ for activation and pore-forming treatment. After washing, it is dried at 60~100℃ to obtain a high-performance lithium-ion sieve particle adsorbent based on lattice engineering.

8. The preparation method according to claim 7, characterized in that: The activation medium includes any one or more combinations of water, dilute acid solution, dilute alkali solution, alcohol-water mixture, and hot water; And / or, the temperature of the activation pore-forming treatment is 20~60℃; And / or, the temperature of the activation pore-forming treatment is 4~20℃; And / or, the temperature of the activation pore-forming treatment is 60~90℃; And / or, the soaking time is 0.5 to 2 hours.

9. A high-performance lithium-ion sieve particle adsorbent based on lattice engineering, prepared by the method according to any one of claims 1-8.

10. The application of the high-performance lithium-ion sieve particle adsorbent based on lattice engineering as described in claim 9 in the extraction of lithium ions, rubidium / cesium ions, magnesium ions, or heavy metal ions from salt lake brine, seawater, geothermal lithium-containing brine, oil and gas field produced water, leachate from waste lithium batteries, or industrial lithium-containing wastewater.

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