A MOFs material with multi-component, hollow multi-shell structure, and a preparation method and application thereof

Abstract

The application discloses a kind of MOFs material with multi-component, hollow multi-shell structure and its preparation method and application, the method includes the following steps: (1) hollow double-shell MOF powder is placed in the solution of organic ligand A, forms suspension A;(2) metal source precursor is added to suspension A, stirring, centrifugation, then add the solution of organic ligand A, form suspension B;(3) suspension B replaces suspension A, repeat step (2), the above process is repeated multiple times, post-processing is carried out, and multi-component hollow double-shell powder coated with a layer of dense particles is obtained;(4) organic ligand B and multi-component hollow double-shell powder are placed in polar solvent, solvent-assisted ligand exchange reaction is carried out, and the product is post-processed to obtain multi-component hollow three-layer core-shell MOFs material.The reaction product obtained by the application can be used to prepare sodium ion battery negative material, and then the electrochemical performance of sodium ion battery can be improved.

Description

Technical Field

[0001] This invention relates to the field of micro / nano composite material synthesis technology, specifically to a MOF material with a multi-component, hollow multi-shell structure, its preparation method, and its application. Background Technology

[0002] Metal-organic frameworks (MOFs), as crystalline porous materials formed by the self-assembly of inorganic metal ions or clusters with organic ligands through coordination bonds, have become a research hotspot in the field of functional materials due to their ultra-high specific surface area, tunable pore size, and diverse topologies. MOFs offer high structural designability; by selecting different metal centers and organic ligands, their pore environment and active site distribution can be precisely controlled, thus demonstrating enormous application potential in fields such as gas adsorption and separation, catalysis, and energy storage.

[0003] However, most pure MOF materials exhibit low electrical conductivity and insufficient chemical stability, which severely limits their application in electrochemical energy storage devices. Furthermore, the microporous structure of MOFs makes it difficult to accommodate large-sized ions (such as Na+). + K + The rapid diffusion requirements of metal-organic frameworks (MOFs) lead to poor rate performance and reversible capacity. Hollow multi-shell MOFs and their derivatives can effectively overcome these shortcomings, but their preparation methods mainly include template-directed methods and interface-induced methods. These methods usually involve multiple steps and have drawbacks such as complex template morphology design, difficulty in control, poor controllability, and harsh template removal conditions. Furthermore, it is difficult to uniformly and controllably introduce metal selenides and other materials into the system while maintaining the integrity of the hollow multi-shell structure. Therefore, developing a multi-component hollow core-shell MOF material that is easy to prepare and inexpensive has significant research significance and practical value. Summary of the Invention

[0004] The purpose of this invention is to provide a multi-component, hollow multi-shell MOF material, its preparation method, and its applications, which expands the applications of MOF materials and enables efficient use in electrochemical energy storage. The multi-component nature of this invention refers to the material containing at least two different metallic elements or at least two different types of MOF structures.

[0005] In one aspect of the present invention, a method for preparing MOFs materials with a multi-component, hollow multi-shell structure is proposed. According to an embodiment of the present invention, the method includes the following steps:

[0006] (1) Place the hollow double-shell MOF powder in a solution of organic ligand A to form suspension A;

[0007] (2) Add the metal source precursor to suspension A, stir, centrifuge, and then add it to the solution of organic ligand A to form suspension B;

[0008] (3) Replace suspension A with suspension B and repeat step (2). Repeat the above process multiple times and perform post-processing on the final product to obtain a multi-component hollow double-shell powder with a layer of dense particles on the surface.

[0009] (4) The organic ligand B and the multi-component hollow double-shell powder with a layer of dense particles on the surface are placed in a polar solvent to carry out a solvent-assisted ligand exchange reaction. After the reaction is completed, the product is post-processed to obtain multi-component hollow three-layer core-shell MOFs material.

[0010] In addition, the method for preparing a MOF material with a multi-component, hollow multi-shell structure according to the above embodiments of the present invention may also have the following additional technical features:

[0011] In some embodiments of the present invention, the hollow double-shell MOF powder in step (1) is replaced with multi-component hollow three-layer core-shell MOFs material, and steps (1) to (4) are repeated to carry out at least one round of iterative reaction to obtain multi-component hollow multi-shell MOFs material;

[0012] Alternatively, after step (4) is completed, replace the hollow double-shell MOF powder in step (1) with multi-component hollow three-layer core-shell MOFs material, repeat steps (1) to (4) for at least one round of iterative reaction, and obtain multi-component hollow multi-shell MOFs material;

[0013] Alternatively, after step (4) is completed, replace the hollow double-shell MOF powder in step (1) with multi-component hollow three-layer core-shell MOFs material, repeat steps (1) to (4) for at least one round of iterative reaction, and then repeat steps (1) to (3) to obtain a multi-component hollow multi-shell MOFs material with a layer of dense particles on the surface.

[0014] Each iteration of the reaction process results in an additional shell layer in the resulting MOF material. The principle is to first coat the surface of the hollow double-shell MOF with a dense layer of particles using a solution method, and then transform the dense layer of particles into a hollow structure using a solvent-assisted ligand exchange method, thereby adding a new shell layer.

[0015] In some embodiments of the present invention, in step (1), the hollow double-shell MOF is a single metal or multi-metal MOF-74, and the metal includes Zn, Co, Ni, Mg, Mn, etc.; in steps (1) and (2), the organic ligand A is 2-methylimidazole or terephthalic acid, etc., 2-methylimidazole is soluble in methanol and has a concentration of 2 to 4 mol / L; the concentration of the hollow double-shell MOF in suspension A is 1 to 4 g / L.

[0016] In some embodiments of the present invention, in step (2): the metal in the metal source precursor can be one or more, including Zn, Co, Ni, Mg, Mn, etc., and the metal source precursor is dissolved in methanol at a concentration of 0.2–1 mol / L; the stirring temperature is 16–24 °C and the stirring time is 10–30 min. Steps (1) and (2) involve coating a layer of MOF fine particles with different structures onto the surface of a hollow double-shell MOF using a solution method. This particle layer can subsequently be transformed into another hollow MOF structure, thereby increasing the number of shells.

[0017] In some embodiments of the present invention, in step (3): the number of repetitions is 3 to 9 times; the post-processing includes centrifugation, washing, and drying, wherein the drying temperature is 50 to 80 ℃ and the drying time is 12 to 24 h. Through repeated operations, the surface of the hollow double-shell MOF is continuously coated with fine particles, eventually forming a dense layer of fine particles on its surface.

[0018] In some embodiments of the present invention, in step (4): the mass ratio of the multi-component hollow double-shell powder to the organic ligand B is 1:(1~2); the organic ligand B is 2,5-dihydroxyterephthalic acid, 1,3,5-triphenylcarboxylic acid, or terephthalic acid, etc.; the polar solvent is N,N-dimethylformamide or N-methylpyrrolidone, etc.; the temperature of the solvent-assisted ligand exchange reaction is 80-160 °C, and the reaction time is 1-16 h; the post-treatment includes centrifugation, washing, and drying, the drying temperature is 50-80 °C, and the drying time is 12-24 h. This is to transform the multi-component dense fine particles coated on the surface of the hollow double-shell MOF into a hollow structure through the solvent-assisted ligand exchange method, thereby achieving the purpose of increasing the shell layer. Different organic ligands B will transform the dense fine particles on the surface into different hollow MOF materials.

[0019] In solvent-assisted ligand exchange reactions, the dense MOF particles on the surface differ from the core in lattice parameters, chemical potential of metal nodes, and coordination configuration. Under solvothermal conditions, the added exogenous organic ligands preferentially exchange with metal ions in the shell particles that are in low coordination positions, promoting a shift in coordination configuration towards higher coordination numbers or more stable configurations. This also causes lattice rearrangement and changes in topology, such as from a SOD-type ZIF to a MOF-74-type honeycomb channel structure. (The last sentence appears to be incomplete and possibly refers to a specific reaction involving Co.) 2+ and Zn 2+ For example, their ionic radii and coordination kinetics differ, resulting in different diffusion rates. Simultaneously, organic ligands migrate inward more slowly due to steric hindrance, leading to the Kirkendall effect: metal ions diffuse outward faster than ligands migrate inward, creating vacancies at the interface. These vacancies converge to form interlayer voids, ultimately forming a hollow structure naturally without additional templates or etching. The structures of different shells also differ; the core retains its original structure, while the outer shell is dominated by new ligands forming a new MOF phase. Regarding the control of the final structure by different organic ligands and MOF materials, the core lies in the fact that the length of the ligands, the functional groups they carry, and the coordination number determine the exchange rate and the magnitude of the lattice strain. For example, the type and valence state of metal nodes affect the ligand exchange activation energy and the rate of phase transition. Therefore, by rationally combining the types of ligands and metals, the interlayer spacing, wall thickness, and pore structure can be controlled.

[0020] In another aspect of the present invention, the present invention proposes a method for preparing MOFs materials with multi-component, hollow multi-shell structures, as described above, to obtain MOFs materials with multi-component, hollow multi-shell structures.

[0021] In another aspect of the invention, a multi-component hollow multi-shell metal@carbon structure material is proposed. According to an embodiment of the invention, the hollow multi-layered core-shell MOF material prepared by the aforementioned method is placed in an argon atmosphere and subjected to high-temperature annealing and carbonization to form a hollow multi-shell metal@carbon structure material. The annealing temperature is 400–800 °C, and the holding time is 2–4 h. If the temperature is too low, the organic ligands in the metal-organic framework will not carbonize completely, and residual impurities will reduce the conductivity of the material and affect its structural stability. If the temperature is too high, the hollow multi-shell structure is prone to collapse or the carbon skeleton becomes excessively dense, weakening its advantages in buffering volume expansion and accelerating ion transport. Within this temperature range, the organic ligands can be fully pyrolyzed while the metal nodes are reduced to uniformly dispersed metal elements, retaining the original hollow multi-shell morphology, thereby obtaining a structurally stable, highly conductive, and uniformly distributed hollow multi-shell metal@carbon structure material.

[0022] In another aspect of the invention, a multi-component hollow multi-shell metal selenide@carbon composite material is proposed. According to an embodiment of the invention, the hollow multi-shell metal@carbon structural material is mixed with selenium powder, and then annealed in an argon atmosphere to obtain the hollow multi-shell metal selenide@carbon composite material. The mass ratio of the hollow multi-shell metal@carbon structural material to the selenium powder is 1:(1-2); the annealing temperature is 300-600 °C, and the holding time is 2-4 h. Below 300 °C, the elemental metal in the metal@carbon mixture is difficult to completely convert into metal selenides, leading to a decrease in specific capacity and electrochemical stability; above 600 °C, the metal selenides are prone to agglomeration, and the carbon skeleton may shrink or collapse, thereby weakening the structural advantages of the hollow multi-shell structure. Within this temperature range, the selenium powder can fully react with uniformly dispersed metal particles to generate well-crystallized and uniformly distributed metal selenides. Furthermore, the material can achieve a high theoretical specific capacity and good conductivity contributed by metal selenides, thereby significantly improving the rate performance and cycle stability of sodium-ion batteries.

[0023] In another aspect, this invention proposes a sodium-ion battery anode material. According to embodiments of the invention, it is prepared using the aforementioned multi-component hollow multi-shell metal@carbon structure or the aforementioned multi-component hollow multi-shell metal selenide@carbon composite material. This is because the metal or metal selenide can undergo a reversible conversion reaction with sodium ions, providing a high theoretical specific capacity, while the hollow multi-shell structure effectively mitigates volume expansion during charge and discharge. Therefore, this material simultaneously possesses the advantages of high capacity, high rate capability, and long cycle stability, making it an ideal anode material for sodium-ion batteries.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1) The multi-component hollow multi-shell metal selenide@carbon composite material prepared in this invention possesses the dual advantages of a hollow multi-shell metal-organic framework structure and metal selenides. In terms of composition, the metal selenides contribute high theoretical specific capacity and good conductivity; structurally, the hollow multi-shell provides ample buffer space, effectively mitigating volume expansion caused by charging and discharging. Furthermore, the hollow multi-shell and carbon framework work together to enhance overall structural stability and shorten ion transport paths within the material. Based on these characteristics, this material significantly improves the electrochemical performance of sodium-ion batteries, such as rate performance and cycle stability.

[0026] 2) The present invention prepares a multi-component hollow multi-shell metal-organic framework. First, it undergoes high-temperature carbonization under a protective atmosphere. During this process, the organic ligands pyrolyze into a supporting carbon skeleton, completely preserving the original hollow multi-shell morphology. Simultaneously, the metal nodes uniformly dispersed in the carbon matrix are reduced in situ to elemental metal nanoparticles. Then, the carbonized product is mixed with selenium powder and subjected to a second annealing under a protective atmosphere. During this process, the selenium evaporates upon heating, thus converting the elemental metal into metal selenides in situ as vapor. Because the metal particles are uniformly dispersed in the carbon matrix and the selenium vapor diffuses uniformly, the hollow multi-shell structure is completely preserved while the metal selenides are uniformly and controllably introduced into the system.

[0027] 3) The method for preparing a metal-organic framework and its derivative materials with a multi-component, hollow multi-shell structure according to the present invention is simple, easy to operate, has a high yield, and is inexpensive.

[0028] 4) The metal-organic framework and its derivative materials with multi-component, hollow multi-shell structure prepared by this invention enrich the types of MOF structural materials, expand the application of MOF materials, and can be efficiently applied to electrochemical energy storage. Attached Figure Description

[0029] Figure 1 These are SEM images of the hollow double-shell Co-MOF-74@ZnCo-ZIF powder prepared in Example 1 of this invention;

[0030] Figure 2 These are TEM images of the hollow double-shell Co-MOF-74@ZnCo-ZIF powder prepared in Example 1 of this invention;

[0031] Figure 3 These are XRD images of the hollow double-shell Co-MOF-74@ZnCo-ZIF powder prepared in Example 1 of this invention;

[0032] Figure 4 These are SEM images of the hollow three-shell Co-MOF-74@ZnCo-MOF-74 powder prepared in Example 1 of this invention;

[0033] Figure 5 These are TEM images of the hollow triple-shell Co-MOF-74@ZnCo-MOF-74 powder prepared in Example 1 of this invention;

[0034] Figure 6 These are XRD images of the hollow triple-shell Co-MOF-74@ZnCo-MOF-74 powder prepared in Example 1 of this invention;

[0035] Figure 7These are TEM images of the hollow four-shell Co-MOF-74@ZnCo-MOF-74@MgCo-MOF-74 powder prepared in Example 3 of this invention;

[0036] Figure 8 These are TEM images of the hollow three-shell porous carbon hybrid material Co@PC prepared in Example 4 of this invention;

[0037] Figure 9 These are XRD images of the hollow three-shell porous carbon hybrid material Co@PC prepared in Example 4 of this invention;

[0038] Figure 10 These are TEM images of the hollow three-shell metal selenide@carbon composite material CoSe2@PC prepared in Example 5 of this invention;

[0039] Figure 11 These are XRD images of the hollow three-shell metal selenide@carbon composite material CoSe2@PC prepared in Example 5 of this invention;

[0040] Figure 12 This is the CV diagram of applying the hollow three-shell porous carbon hybrid material Co@PC to a sodium-ion battery in Application Example 1 of this invention;

[0041] Figure 13 The figures (a) and (b) are from Application Example 1 of this invention, showing the rate performance (a) and cycle performance (b) of applying the hollow three-shell porous carbon hybrid material Co@PC to a sodium-ion battery.

[0042] Figure 14 This is the CV diagram of applying the hollow three-shell metal selenide@carbon composite material CoSe2@PC to a sodium-ion battery in Application Example 2 of this invention;

[0043] Figure 15 The figures (a) and (b) are from Application Example 2 of this invention, showing the rate performance (a) and cycle performance (b) of the hollow triple-shell metal selenide@carbon composite material CoSe2@PC applied to a sodium-ion battery.

[0044] Figure 16 This is a SEM image of the hollow triple-shell Co-MOF-74@ZnCo-MOF-74 powder prepared in Example 1 of this invention. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0046] Example 1

[0047] A method for preparing hollow three-shell Co-MOF-74@ZnCo-MOF-74 powder includes the following steps:

[0048] (1) Preparation of hollow double-shell Co-MOF-74@ZnCo-ZIF powder

[0049] a. Dissolve 0.291 g of cobalt nitrate hexahydrate and 0.297 g of zinc nitrate hexahydrate in 10 ml of methanol to form solution A; dissolve 8 g of 2-methylimidazole in 30 ml of methanol to form solution B, then add 30 mg of hollow double-shell Co-MOF-74 powder to solution B to form a suspension; slowly add solution A to the suspension, stir at room temperature, and react for 15 min;

[0050] b. Prepare new solutions A and B. After the reaction is complete, centrifuge the product and add it to the new solution B to form a suspension. Slowly add solution A to the suspension and stir at room temperature for 15 min. Repeat the above process six times. After washing with water and ethanol several times, dry the product in a 60 ℃ oven for 16 h to obtain hollow double-shell Co-MOF-74@ZnCo-ZIF powder.

[0051] (2) 25 mg of 2,5-dihydroxyterephthalic acid and 20 mg of hollow double-layer Co-MOF-74@ZnCo-ZIF core-shell structure powder prepared in Example 1 were placed in 80 ml of N,N-dimethylformamide and ultrasonically dispersed for 30 min to form a mixture. Then, the mixture was transferred to a high-pressure reactor and placed in an 80 °C oven for 800 min.

[0052] (3) After the reaction is complete, the product is centrifuged, washed several times with water and ethanol, and then dried in a 60 °C oven to obtain hollow triple-shell Co-MOF-74@ZnCo-MOF-74 powder.

[0053] Figure 1 This is a scanning electron microscope image of the hollow double-shell Co-MOF-74@ZnCo-ZIF powder prepared in this embodiment. The image shows that the hexahedral size is approximately 400-600 nm, and the surface is covered with a dense layer of fine particles. Figure 2 This is a transmission electron microscope image of Co-MOF-74@ZnCo-ZIF. The image shows that it has a double-layered hollow core-shell structure, consisting of a hollow double-shelled Co-MOF-74 and a ZnCo-ZIF coating on its surface, from the inside out. Figure 3The XRD pattern shows that Example 1 successfully prepared a hollow double-layer Co-MOF-74@ZnCo-ZIF core-shell structure, and its diffraction peaks correspond one-to-one with the standard spectrum.

[0054] Figure 4 and Figure 16 This is a scanning electron microscope image of the hollow triple-shell Co-MOF-74@ZnCo-MOF-74 powder prepared in this embodiment, whose surface is also coated with a layer of dense particles. Figure 5 This is a transmission electron microscope image of hollow triple-shell Co-MOF-74@ZnCo-MOF-74, which reveals its hollow triple-shell structure. Figure 6 The XRD pattern shows that hollow triple-shell Co-MOF-74@ZnCo-MOF-74 was successfully prepared in this embodiment. From the inside out, it consists of hollow double-shell Co-MOF-74 and hollow ZnCo-MOF-74 coated on its surface. Its diffraction peaks correspond one-to-one with the standard spectrum.

[0055] Example 2

[0056] A method for preparing hollow three-shell Co-MOF-74@ZnCo-MOF-74@MgCo-ZIF powder includes the following steps:

[0057] (1) Dissolve 0.291 g of cobalt nitrate hexahydrate and 0.256 g of magnesium nitrate hexahydrate in 10 ml of methanol to form solution A; dissolve 8 g of 2-methylimidazole in 30 ml of methanol to form solution B, and then add 30 mg of hollow triple-shell Co-MOF-74@ZnCo-MOF-74 powder prepared in Example 1 to solution B to form a suspension; slowly add solution A to the suspension, stir at room temperature, and react for 15 min;

[0058] (2) Prepare new solutions A and B. After the reaction is complete, centrifuge the product and add it to the new solution B to form a suspension. Slowly add solution A to the suspension and stir at room temperature for 15 min. Repeat the above process six times. After washing with water and ethanol several times, dry the product in a 60℃ oven to obtain hollow triple-shell Co-MOF-74@ZnCo-MOF-74@MgCo-ZIF powder. From the inside out, the powder consists of hollow double-shell Co-MOF-74, hollow ZnCo-MOF-74, and MgCo-ZIF coated on its surface.

[0059] Example 3

[0060] A method for preparing hollow four-shell Co-MOF-74@ZnCo-MOF-74@MgCo-MOF-74 powder includes the following steps:

[0061] (1) 25 mg of 2,5-dihydroxyterephthalic acid and 20 mg of hollow three-shell Co-MOF-74@ZnCo-MOF-74@MgCo-ZIF powder prepared in Example 2 were placed in 80 ml of N,N-dimethylformamide and ultrasonically dispersed for 30 min to form a mixture. Then the mixture was transferred to a high-pressure reactor and placed in an 80°C oven for 800 min.

[0062] (2) After the reaction is complete, the product is centrifuged and washed with water and ethanol several times in sequence, and then dried in an oven at 60°C for 16 h to obtain hollow four-shell Co-MOF-74@ZnCo-MOF-74@MgCo-MOF-74 powder.

[0063] (3) Figure 7 These are transmission electron microscope (TEM) images of hollow tetrashell Co-MOF-74@ZnCo-MOF-74@MgCo-MOF-74. They reveal a hollow tetrashell structure, consisting of hollow double-shell Co-MOF-74, hollow ZnCo-MOF-74, and hollow MgCo-MOF-74 from the inside out.

[0064] Example 4

[0065] A method for preparing hollow three-shell porous carbon hybrid material Co@PC includes the following steps:

[0066] The hollow three-shell Co-MOF-74@ZnCo-MOF-74 powder prepared in Example 1 was placed in a tube furnace under an argon atmosphere and annealed at a high temperature of 700 °C, with a heating rate of 2 °C / min and a holding time of 3 h, to obtain the hollow three-shell porous carbon hybrid material Co@PC.

[0067] Figure 8 This is a transmission electron microscope image of the hollow three-layer core-shell porous carbon hybrid material Co@PC prepared in this embodiment, showing that it has a hollow three-layer core-shell structure. Figure 9 The XRD pattern shows that the hollow three-shell porous carbon hybrid material Co@PC was successfully prepared in this embodiment.

[0068] Example 5

[0069] A method for preparing hollow three-shell metal selenide@carbon composite material CoSe2@PC includes the following steps:

[0070] The hollow three-shell porous carbon hybrid material Co@PC prepared in Example 4 was mixed with selenium powder at a mass ratio of 1:1, and then annealed in an argon atmosphere at a temperature of 500 °C, a heating rate of 2 °C / min, and a holding time of 3 h to obtain the hollow three-shell metal selenide@carbon composite material CoSe2@PC.

[0071] Figure 10 This is a transmission electron microscope image of the hollow three-shell metal selenide@carbon composite material CoSe2@PC prepared in this embodiment, showing that it has a hollow three-shell core-shell structure. Figure 11 The XRD pattern shows that Example 6 successfully prepared a hollow three-shell metal selenide@carbon heterojunction CoSe2@PC.

[0072] Application Example 1

[0073] A method for preparing sodium-ion battery anode materials includes the following steps:

[0074] (1) The hollow three-shell porous carbon hybrid material Co@PC, conductive carbon black and PVDF prepared in Example 4 were uniformly mixed in 1-methyl-2-pyrrolidone (NMP) at a mass ratio of 8:1:1 to form a slurry, which was then uniformly coated on a copper foil current collector and dried in a vacuum drying oven at 60 °C for 24 h.

[0075] (2) The dried copper foil current collector was sliced ​​to make the working electrode, glass fiber was used as the diaphragm, and NaPF6 was used as the electrolyte. A CR2032 sodium-ion half-cell was assembled in an argon-filled glove box. The test voltage range was 0.01V-3V vs Na + / Na.

[0076] Application Example 2

[0077] A method for preparing sodium-ion battery anode materials includes the following steps:

[0078] (1) The hollow triple-shell metal selenide@carbon composite material CoSe2@PC, conductive carbon black and PVDF prepared in Example 5 were uniformly mixed in 1-methyl-2-pyrrolidone (NMP) at a mass ratio of 8:1:1 to form a slurry, which was then uniformly coated on a copper foil current collector and dried in a vacuum drying oven at 60 °C for 24 h.

[0079] (2) The dried copper foil current collector was sliced ​​to make the working electrode, glass fiber was used as the diaphragm, and NaPF6 was used as the electrolyte. A CR2032 sodium-ion half-cell was assembled in an argon-filled glove box. The test voltage range was 0.01V-3V vs Na + / Na.

[0080] Figure 12 and Figure 14 This is a CV diagram of hollow three-shell porous carbon hybrid material Co@PC and hollow three-shell metal selenide@carbon composite material CoSe2@PC applied to sodium-ion batteries. Figure 12 It can be seen that the scanning curves of the last two cycles basically overlap, indicating that it has good reversibility. Figure 14 The small shift in the peak positions of the middle and latter two rings indicates that the selenization reaction is complete and the structure is stable. Figure 13 and Figure 15 The figures show the sodium electrochemical storage performance of Co@PC (a hollow three-shell porous carbon hybrid material) and CoSe2@PC (a hollow three-shell metal selenide@carbon composite material). It can be seen that both materials exhibit relatively stable reversible capacity at different current densities and have less capacity decay at high rates, indicating that both have good sodium electrochemical performance, with CoSe2@PC having a higher reversible specific capacity.

[0081] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the present invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for preparing MOFs materials with multi-component, hollow multi-shell structure, characterized in that, Includes the following steps: (1) Place the hollow double-shell MOF powder in a solution of organic ligand A to form suspension A; (2) Add the metal source precursor to suspension A, stir, centrifuge, and then add it to the solution of organic ligand A to form suspension B; (3) Replace suspension A with suspension B and repeat step (2). Repeat the above process multiple times and perform post-processing on the final product to obtain a multi-component hollow double-shell powder with a layer of dense particles on the surface. (4) The organic ligand B and the multi-component hollow double-shell powder with a layer of dense particles on the surface are placed in a polar solvent to carry out a solvent-assisted ligand exchange reaction. After the reaction is completed, the product is post-processed to obtain multi-component hollow three-layer core-shell MOFs material.

2. The method for preparing a MOF material with a multi-component, hollow multi-shell structure according to claim 1, characterized in that: After step (4) is completed, the hollow double-shell MOF powder in step (1) is replaced with multi-component hollow three-layer core-shell MOFs material, and steps (1) to (3) are repeated to obtain multi-component hollow three-layer core-shell MOFs material with a layer of dense particles on the surface. Alternatively, after step (4) is completed, replace the hollow double-shell MOF powder in step (1) with multi-component hollow three-layer core-shell MOFs material, repeat steps (1) to (4) for at least one round of iterative reaction, and obtain multi-component hollow multi-shell MOFs material; Alternatively, after step (4) is completed, replace the hollow double-shell MOF powder in step (1) with multi-component hollow three-layer core-shell MOFs material, repeat steps (1) to (4) for at least one round of iterative reaction, and then repeat steps (1) to (3) to obtain a multi-component hollow multi-shell MOFs material with a layer of dense particles on the surface.

3. The method for preparing a MOF material with a multi-component, hollow multi-shell structure according to claim 1, characterized in that: In step (1), the hollow double-shell MOF is a single-metal or multi-metal MOF-74; In steps (1) and (2), the organic ligand A is 2-methylimidazole or terephthalic acid.

4. The method for preparing a MOF material with a multi-component, hollow multi-shell structure according to claim 1, characterized in that, In step (2): The metal in the metal source precursor is one or more of Zn, Co, Ni, Mg, and Mn; The stirring temperature is 16–24 °C, and the stirring time is 10–30 min.

5. The method for preparing a MOF material with a multi-component, hollow multi-shell structure according to claim 1, characterized in that, In step (3): The number of repetitions is 3 to 9 times; The post-processing includes centrifugation, washing, and drying. The drying temperature is 50–80 °C, and the drying time is 12–24 h.

6. The method for preparing a MOF material with a multi-component, hollow multi-shell structure according to claim 1, characterized in that, In step (4): The mass ratio of the multi-component hollow double-shell powder to organic ligand B is 1:(1~2). The organic ligand B is 2,5-dihydroxyterephthalic acid, 1,3,5-benzenetricarboxylic acid, or terephthalic acid. The polar solvent is N,N-dimethylformamide or N-methylpyrrolidone; The solvent-assisted ligand exchange reaction is carried out at a temperature of 80–160 °C for a time of 1–16 h. The post-processing includes centrifugation, washing, and drying. The drying temperature is 50–80 °C, and the drying time is 12–24 h.

7. A MOF material with a multi-component, hollow multi-shell structure prepared by the method of any one of claims 1-6.

8. A multi-component hollow multi-shell metal@carbon structural material, characterized in that: The MOFs material with a multi-component, hollow multi-shell structure as described in claim 7 is placed in an argon atmosphere and subjected to high-temperature annealing and carbonization to form a multi-component hollow multi-shell metal@carbon structure material.

9. A multi-component hollow multi-shell metal selenide@carbon composite material, characterized in that: The multi-component hollow multi-shell metal@carbon structural material of claim 8 is mixed with selenium powder and then annealed in an argon atmosphere to obtain the multi-component hollow multi-shell metal selenide@carbon composite material.

10. A sodium-ion battery anode material, characterized in that: It is prepared using the multi-component hollow multi-shell metal@carbon structure of claim 8 or the multi-component hollow multi-shell metal selenide@carbon composite material of claim 9.

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