An asymmetric hybrid mesoporous material, a preparation method and application thereof

Abstract

The application discloses an asymmetric hybrid mesoporous material and a preparation method and application thereof, and belongs to the technical field of mesoporous materials; the preparation method comprises the following steps: taking a template agent, a pore expanding agent and an organic silicon source as the basis, combining SiO2 nanospheres and an organic silane capping agent to prepare superstructure silicon spheres; then, the superstructure silicon spheres are dispersed in an alcohol-water mixed solvent, dopamine hydrochloride is added, and in-situ polymerization is carried out under the action of ammonia water to obtain an asymmetric mesoporous material. The material has a high specific surface area and a rich hierarchical pore structure, and the mesoporous superstructure silicon sphere constructed by the SiO2 nanospheres is one end, and the polydopamine layer is the other end. The application has the advantages of simple process and mild conditions, and the material morphology and size can be controlled by adjusting reaction parameters. When the material is applied to a water-based zinc ion battery negative electrode, the specific capacity, cycle stability and rate performance of the battery can be significantly improved, the zinc dendrite growth and side reactions can be effectively inhibited, and the material has important energy storage application value.

Description

Technical Field

[0001] This invention belongs to the field of mesoporous materials technology, specifically relating to an asymmetric hybrid mesoporous material, its preparation method, and its application. Background Technology

[0002] Aqueous zinc-ion batteries have become a research hotspot for next-generation energy storage systems due to their high safety, low cost, and environmental friendliness. However, their further development is limited by electrode materials, which suffer from problems such as low specific capacity, poor cycle stability, and slow ion diffusion rate.

[0003] Mesoporous materials, due to their high specific surface area and abundant pore structure, can effectively enhance ion transport rates and electrochemical performance. However, traditional mesoporous materials are usually symmetrical in structure, making it difficult to simultaneously meet the requirements of high conductivity and high specific capacity. Asymmetric mesoporous materials, by combining two or more materials with different functions, can achieve synergistic effects and significantly improve battery performance. However, current preparation methods for asymmetric mesoporous materials are complex, and research on their application in aqueous zinc-ion batteries is limited. Therefore, developing a simple and efficient preparation method for asymmetric mesoporous materials and exploring their application in aqueous zinc-ion batteries has significant scientific and practical value. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide an asymmetric hybrid mesoporous material, its preparation method, and its applications. This material possesses high specific surface area, abundant pore structure, and excellent electrochemical performance. The present invention applies this asymmetric hybrid mesoporous material to the anode of an aqueous zinc-ion battery to improve the battery's specific capacity, cycle stability, and rate performance.

[0005] This invention is achieved through the following technical solution:

[0006] In a first aspect, the present invention provides a method for preparing an asymmetric hybrid mesoporous material, comprising the following steps:

[0007] Step 1: Preparation of superstructured silicon spheres: First, the template agent is dissolved in an inorganic acid solution with a concentration of 1-8 mol / L and stirred evenly to form a template agent solution with a concentration of 1.5-5 wt%. Then, a pore-expanding agent is added to the template agent solution and stirred continuously for 2-24 hours to form a nanoemulsion. An organosilicon source is added and stirred at room temperature for 0.5-10 hours. Then, SiO2 nanospheres with a particle size of 200-500 nm are added and stirred for 1-10 hours. Next, an organosilicon end-capping agent is added and stirred for another 2-24 hours to obtain a mixed solution. Finally, the mixed solution is centrifuged, washed, and dried sequentially to obtain superstructured silicon spheres.

[0008] Step 2: Preparation of dispersion: The superstructured silica spheres obtained in Step 1 are dispersed in a mixed solvent of alcohol and water, wherein the volume ratio of alcohol to water is 1:1, and fully dispersed to form a clear and transparent dispersion; dopamine hydrochloride is added to the dispersion; and the mixture is stirred for 0.5-10 hours.

[0009] Step 3: Synthesis of asymmetric materials: Add ammonia to the solution obtained in Step 2, and continue stirring at room temperature for 0.5-10 hours. After the reaction is completed, separate, wash and dry to obtain asymmetric mesoporous materials.

[0010] Further, in step one, the mass ratio of the template agent, pore-expanding agent, organosilicon source, SiO2 nanospheres and organosilicon end-capping agent is 5-7:5-7:5-7:1-2:2-3; the stirring speed is 50-15000 r / min.

[0011] Furthermore, the template agent is F127(EO) 106 -PO 70 -EO 106 ), F68 (EO) 132 -PO 30 -EO 132 ), F98 (EO) 132 -PO 45 -EO 132 P85 (EO) 26 -PO 39 -EO 20 ), P123 (EO) 20 -PO 70 -EO 20 F108 (EO) 132 -PO 50 -EO 132 ), F88 (EO) 132 -PO 40 -EO 132 ), F87 (EO) 106 -PO 40 -EO 106 One or more of the following;

[0012] The pore-expanding agent is one or more of benzene, toluene, and trimethylbenzene;

[0013] The organosilicon source is one or more of tetraethyl orthosilicate, 1,2-bis(triethoxysilyl)ethane, and dimethyldimethoxysilane;

[0014] The organosilane end-capping agent is one or more of dimethyldimethoxysilane and dimethyldiethoxysilane.

[0015] Furthermore, in step one, the inorganic acid is one or more of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, hydroiodic acid, hydrobromic acid, and hydrofluoric acid.

[0016] Furthermore, in step one, the centrifugation speed is 5000-10000 rpm, and the centrifugation time is 8-15 min.

[0017] Furthermore, in step one, the washing process involves first washing with distilled water 1-5 times, followed by washing with anhydrous ethanol 1-5 times.

[0018] Further, in step one, the drying process is as follows: the washed product is dispersed in anhydrous ethanol to prepare an alcohol dispersion with a concentration of 0.1-0.5 mol / L, and then the solvent is evaporated at 40-80℃ for 2-48 hours.

[0019] Furthermore, in step two, the mass ratio of dopamine hydrochloride to superstructured silicon spheres is 0.5:1 to 5:1.

[0020] Secondly, the present invention provides an asymmetric hybrid mesoporous material having an asymmetric structure, wherein a mesoporous superstructured silicon sphere constructed with SiO2 nanospheres as the core is one end, and a polydopamine layer generated by in-situ polymerization is the other end, wherein the size of the polydopamine layer is 130-280 nm.

[0021] Thirdly, the present invention provides an application of an asymmetric mesoporous material in the anode material of an aqueous zinc-ion battery.

[0022] Compared with the prior art, the advantages of the present invention are as follows:

[0023] 1. This invention employs a bottom-up assembly strategy, first constructing SiO2@single-micelle superstructured silicon spheres as "seeds," and then efficiently building asymmetric mesoporous materials through selective polymerization growth of dopamine on their surface. The process is simple, the reaction conditions are mild, and the size of the polydopamine portion and the superstructured silicon sphere portion in the asymmetric structure can be precisely controlled by adjusting the amount of dopamine, the reaction time, and the size of the silicon spheres.

[0024] 2. The asymmetric mesoporous material prepared by this invention combines the structural rigidity of inorganic silicon-based mesoporous materials with the good conductivity and interfacial compatibility of organic polydopamine layers; the asymmetric structure provides richer heterogeneous interfaces and hierarchical channels, which is beneficial for electrolyte wetting and rapid ion transport.

[0025] 3. The asymmetric mesoporous material prepared by this invention has a high specific surface area (421 m²). 2 With its excellent hydrophobic properties (g / g), it can significantly improve the long-cycle stability of aqueous zinc-ion batteries when applied as the anode. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0027] Figure 1 This is a schematic diagram illustrating the formation process of the asymmetric mesoporous material in an embodiment of the present invention;

[0028] Figure 2 This is a 200 nm transmission electron microscope (TEM) image of the asymmetric mesoporous material prepared in Example 1 of the present invention;

[0029] Figure 3 This is a transmission electron microscope (TEM) image of the asymmetric mesoporous material prepared in Example 2 of the present invention;

[0030] Figure 4 This is a transmission electron microscope (TEM) image of the asymmetric mesoporous material prepared in Example 3 of the present invention;

[0031] Figure 5 This is a transmission electron microscope (TEM) image of the asymmetric mesoporous material prepared in Example 4 of the present invention;

[0032] Figure 6 This is a transmission electron microscope (TEM) image of the asymmetric mesoporous material prepared in Example 5 of the present invention;

[0033] Figure 7 This is a transmission electron microscope (TEM) image of the asymmetric mesoporous material prepared in Comparative Example 1 of the present invention;

[0034] Figure 8 This is a specific surface area curve of the asymmetric mesoporous material prepared in Example 1 of the present invention;

[0035] Figure 9 This is a hydrophobic angle diagram of the asymmetric mesoporous material prepared in Example 1 of the present invention;

[0036] Figure 10 Cycle stability test results for aqueous zinc-ion batteries using the asymmetric mesoporous materials prepared in Examples 1-5 and Comparative Example 1 as negative electrode coatings, and batteries using bare zinc negative electrodes. Detailed Implementation

[0037] To clearly and completely describe the technical solution and its specific working process of the present invention, the specific embodiments of the present invention are as follows, in conjunction with the accompanying drawings:

[0038] Example 1

[0039] like Figure 1 As shown, this embodiment provides a method for preparing an asymmetric mesoporous material, including the following steps:

[0040] Step 1: First, while continuously stirring at room temperature, add 0.25g of template agent F108 (EO) 132 -PO 50 -EO 132 The template agent was fully dissolved in 15 mL of 2 mol / L hydrochloric acid to prepare a 3.5 wt% template agent solution. To construct a stable nanoemulsion, 300 μL of trimethylbenzene was introduced into the solution as a pore-expanding agent. Subsequently, 280 μL of tetraethyl orthosilicate (TEOS) was added dropwise as an organosilicon source, and the reaction system was kept stirred at room temperature for 1 h.

[0041] Next, 1 mL of a 1 mol / L SiO2 nanosphere alcohol solution was added, and the reaction was stirred for another 4 h. Surface modification was achieved by dropwise addition of 130 μL of the end-capping agent dimethyldimethoxysilane, and the reaction continued for another 24 h. The resulting mixture was then centrifuged at 8000 rpm for 10 min. A purification process followed, including three washing cycles each with distilled water and anhydrous ethanol. Finally, the product was placed in a 40°C drying oven for solvent evaporation for 48 h to obtain solid-state superstructured silicon spheres.

[0042] The preparation method of the SiO2 nanosphere alcohol solution is as follows: Silica nanospheres (approximately 350 nm) used as hard templates were synthesized via the Stöber method. Solution A was prepared by mixing 24.75 mL of deionized water, 16.25 mL of ethanol, and 9.0 mL of concentrated ammonia solution in a 100 mL round-bottom flask under vigorous stirring. Separately, 4.50 mL of LTEOS was dispersed in 45.5 mL of anhydrous ethanol to prepare solution B. The reaction was initiated by rapidly pouring solution B into solution A and then vigorously stirred at 25 °C for 2 h. The precipitate was centrifuged and washed three times. The resulting SiO2 nanospheres with a particle size distribution of 200–500 nm were redispersed in ethanol to form a homogeneous solution with a concentration of 1.0 mg / mL. The SiO2 nanospheres were used as hard templates for constructing the superstructure.

[0043] Step 2: Preparation of dispersion:

[0044] 0.1g of superstructured silicon spheres were dispersed in a solution of ethanol:water = 1:1 (volume ratio), and ultrasonicated to disperse them evenly, forming a clear and transparent solution. Then, 0.15g of dopamine hydrochloride was added and stirred for 30 minutes to form a uniform and transparent solution.

[0045] Step 3: Preparation of asymmetric mesoporous materials:

[0046] Add 0.35 ml of ammonia to the solution in step two and stir at room temperature for 4 hours to finally obtain the asymmetric mesoporous material.

[0047] The microstructure of the asymmetric mesoporous material prepared in Example 1 was observed using transmission electron microscopy (TEM), and the results are as follows: Figure 2 As shown, from Figure 2 As can be seen, the material exhibits a distinct asymmetric structure, with the polydopamine portion measuring approximately 280 nm.

[0048] Example 2

[0049] The difference between this embodiment and Embodiment 1 is that the amount of dopamine hydrochloride added in step two is 0.1g, and the reaction is carried out by stirring at room temperature for 2 hours.

[0050] The asymmetric material prepared in Example 2 was observed for its microstructure using transmission electron microscopy (TEM), and the results are as follows: Figure 3 ,from Figure 3 It can be seen that the dopamine size of the asymmetric material prepared in Example 2 is 190 nm.

[0051] Example 3

[0052] The difference between this embodiment and embodiment 1 is that the amount of dopamine hydrochloride added in step (3) is 0.05g, and the reaction is stirred at room temperature for 1h.

[0053] The asymmetric material prepared in Example 3 was observed for its microstructure using transmission electron microscopy (TEM), and the results are as follows: Figure 4 ,from Figure 4 It can be seen that the dopamine size of the asymmetric mesoporous material prepared in Example 3 is about 130 nm.

[0054] Example 4

[0055] The difference between this embodiment and Example 1 is that the SiO2 nanospheres added in step (1) are approximately 300 nm in size, resulting in a superstructured silicon sphere with a size of approximately 350 nm. The asymmetric material prepared in Example 4 was observed for its microstructure using a transmission electron microscope (TEM), and the results are as follows: Figure 5 ,from Figure 5 It can be seen that the size of the superstructured silicon spheres of the asymmetric mesoporous material prepared in Example 4 is about 350 nm.

[0056] Example 5

[0057] The difference between this embodiment and embodiment 1 is that the SiO2 nanospheres added in step (1) are about 200 nm in size, and the final superstructure silicon spheres are about 250 nm in size.

[0058] The asymmetric material prepared in Example 5 was observed for its microstructure using transmission electron microscopy (TEM), and the results are as follows: Figure 6 ,from Figure 6 It can be seen that the size of the superstructured silicon spheres of the asymmetric mesoporous material prepared in Example 4 is about 250 nm.

[0059] Comparative Example 1

[0060] The difference between this comparative example and Example 1 is that the organosilane end-capping agent dimethyldimethoxysilane in step (1) is not added, while the other steps are the same.

[0061] The microstructure of the materials prepared in the comparative example was observed using transmission electron microscopy (TEM), and the results are as follows: Figure 7 ,from Figure 7 It can be seen that the material prepared in Comparative Example 1 is not an asymmetric mesoporous material, but a fully encapsulated morphology, with dopamine on the outer layer and superstructured silicon spheres on the inner layer.

[0062] The experiment used Examples 1-5 and Comparative Example 1 as negative electrode coatings for aqueous zinc-ion batteries, and tested their electrochemical cycle stability against bare zinc. The results are as follows: Figure 10 As shown, by Figure 10 It can be seen that the modified coating prepared in Example 1 has the longest electrochemical cycling stability, up to 1100h. In contrast, the cycling stability of the modified coatings in the other examples (2-5), Comparative Example 1, and the bare zinc anode is much lower than that of Example 1. This test result fully confirms that the anode coating prepared in Example 1 can play an efficient protective role for the zinc anode, effectively suppressing problems such as dendrite growth and hydrogen evolution side reactions during the cycling process of the zinc anode in aqueous electrolyte, thereby significantly improving the electrochemical cycling stability of the zinc anode and exhibiting excellent electrochemical performance.

[0063] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0064] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0065] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for preparing an asymmetric hybrid mesoporous material, characterized in that, Includes the following steps: Step 1: Preparation of superstructured silicon spheres: First, the template agent is dissolved in an inorganic acid solution with a concentration of 1-8 mol / L and stirred evenly to form a template agent solution with a concentration of 1.5-5 wt%. Then, a pore-expanding agent is added to the template agent solution and stirred continuously for 2-24 hours to form a nanoemulsion. An organosilicon source is added and stirred at room temperature for 0.5-10 hours. Then, SiO2 nanospheres with a particle size of 200-500 nm are added and stirred for 1-10 hours. Next, an organosilicon end-capping agent is added and stirred for another 2-24 hours to obtain a mixed solution. Finally, the mixed solution is centrifuged, washed, and dried sequentially to obtain superstructured silicon spheres. Step 2: Preparation of dispersion: The superstructured silica spheres obtained in Step 1 are dispersed in a mixed solvent of alcohol and water, wherein the volume ratio of alcohol to water is 1:1, and fully dispersed to form a clear and transparent dispersion; dopamine hydrochloride is added to the dispersion; and the mixture is stirred for 0.5-10 hours. Step 3: Synthesis of asymmetric materials: Add ammonia water to the solution obtained in Step 2, and continue stirring at room temperature for 0.5-10 hours. After the reaction is completed, separate, wash and dry to obtain asymmetric mesoporous materials. The template agent is F127, F68, or F98 (EO). 132 -PO 45 -EO 132 One or more of the following: P85, P123, F108, F88, and F87; The pore-expanding agent is one or more of benzene, toluene, and trimethylbenzene; The organosilicon source is one or more of tetraethyl orthosilicate, 1,2-bis(triethoxysilyl)ethane, and dimethyldimethoxysilane; The organosilane end-capping agent is one or more of dimethyldimethoxysilane and dimethyldiethoxysilane.

2. The method for preparing an asymmetric hybrid mesoporous material as described in claim 1, characterized in that, In step one, the mass ratio of the template agent, pore-expanding agent, organosilicon source, SiO2 nanospheres and organosilicon end-capping agent is 5-7:5-7:5-7:1-2:2-3; the stirring speed is 50-15000 r / min.

3. The method for preparing an asymmetric hybrid mesoporous material as described in claim 1, characterized in that, In step one, the inorganic acid is one or more of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, hydroiodic acid, hydrobromic acid, and hydrofluoric acid.

4. The method for preparing an asymmetric hybrid mesoporous material as described in claim 1, characterized in that, In step one, the centrifugation speed is 5000-10000 rpm and the centrifugation time is 8-15 min.

5. The method for preparing an asymmetric hybrid mesoporous material as described in claim 1, characterized in that, In step one, the washing process involves washing with distilled water 1-5 times, followed by washing with anhydrous ethanol 1-5 times.

6. The method for preparing an asymmetric hybrid mesoporous material as described in claim 1, characterized in that, In step one, the drying process is as follows: the washed product is dispersed in anhydrous ethanol to prepare an alcohol dispersion with a concentration of 0.1-0.5 mol / L, and then the solvent is evaporated at 40-80℃ for 2-48 hours.

7. The method for preparing an asymmetric hybrid mesoporous material as described in claim 1, characterized in that, In step two, the mass ratio of dopamine hydrochloride to superstructured silicon spheres is 0.5:1 to 5:

1.

8. An asymmetric hybrid mesoporous material, characterized in that, The asymmetric hybrid mesoporous material obtained by the preparation method according to any one of claims 1-7 has an asymmetric structure, wherein a mesoporous superstructured silicon sphere constructed with SiO2 nanospheres as the core is one end, and a polydopamine layer generated by in-situ polymerization is the other end, and the size of the polydopamine layer is 130-280 nm.

9. The application of the asymmetric hybrid mesoporous material as described in claim 8 in the anode material of aqueous zinc-ion batteries.

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