A method for preparing and applying 3D-printed silicon-based composite structural materials

Abstract

This invention relates to a method for preparing and applying a 3D-printed silanene-based composite material. The preparation method includes the following steps: (1) adding silanene nanosheets and graphene oxide sequentially to an aqueous solution of cellulose nanofibers, dispersing them ultrasonically each time to obtain a high-concentration fluid; subjecting the high-concentration fluid to planetary degassing and centrifugation to obtain 3D printing ink; (2) using the 3D printing ink and printing a three-dimensional structure using a direct-write 3D printer; (3) preparing a silanene-based composite material by freeze-drying and high-temperature reduction of the three-dimensional structure. This material combines the significant manufacturing advantages of 3D printing technology and has an excellent continuous hierarchical porous structure, which can significantly improve hydrogen conductivity and hydrogen storage capacity, and has application value in hydrogen storage, capacitors, batteries and other fields.

Description

Technical Field

[0001] This invention relates to the field of hydrogen storage material preparation technology, specifically to a method for preparing and applying a 3D-printed silanene-based composite structural material. Background Technology

[0002] Hydrogen energy is a recognized clean energy source that can replace fossil fuels. However, hydrogen storage has always been the biggest bottleneck and obstacle limiting the large-scale utilization of hydrogen energy. Exploring suitable hydrogen storage materials remains one of the main research directions in the field of hydrogen storage today.

[0003] Studies have found that the structural properties of materials have a significant impact on their hydrogen storage capacity. Among them, porous materials, due to their large specific surface area, abundant pore structure, and active sites, have been extensively studied in the field of hydrogen storage. A Chinese patent discloses a platinum-supported nitrogen / sulfur co-doped porous carbon nanofiber material and its preparation and application (authorization announcement number: CN113089136B), which significantly improves catalytic activity and mass hydrogen storage density. Another Chinese patent discloses a cobalt-sulfur hydrogen storage composite material containing porous polyaniline / reduced graphene oxide and its preparation method (application publication number: CN113054181A), whose 3D network structure greatly improves the hydrogen storage performance of cobalt-sulfur alloys. However, the preparation processes of porous materials involved in these reports are relatively complex. How to combine the inherent advantages of materials and achieve controlled preparation of porous materials through simplified processes is currently a key research focus and challenge in the field of hydrogen storage materials.

[0004] It should be noted that the above content falls within the inventor's technical knowledge and does not necessarily constitute prior art. Summary of the Invention

[0005] The purpose of this invention is to solve the problems existing in the prior art and provide a method for preparing and applying 3D printed silene-based composite structural materials. Using silene nanosheets as the base material, printing ink is prepared by mixing with graphene oxide and cellulose nanofibers. A three-dimensional structure with continuous hierarchical porous structure is prepared by direct writing 3D printing, which not only simplifies the preparation process, but also achieves efficient hydrogen storage.

[0006] The present invention achieves the above objectives by adopting the following technical solutions: A method for preparing a 3D-printed silicon-based composite structural material includes the following steps: (1) Add silicene nanosheets and graphene oxide to an aqueous solution of cellulose nanofibers in sequence, and disperse them by ultrasonication each time to obtain a high-concentration fluid; then treat the high-concentration fluid by planetary degassing and centrifugation to obtain 3D printing ink. (2) Using the 3D printing ink obtained in step (1), a three-dimensional structure is printed using a direct-write 3D printer; (3) The three-dimensional structure printed in step (2) is freeze-dried and reduced at high temperature to prepare a silicon-based composite material.

[0007] The mass concentration of the cellulose nanofiber aqueous solution in step (1) is 0.5~1.5%, and the mass ratio of the silicene nanosheets, graphene oxide and cellulose nanofiber aqueous solution is 1~2:1~5:100~130.

[0008] In step (1), the ultrasonic dispersion power is 200W and the dispersion time is 30min. The planetary degassing and stirring speed is 1500~2000r / min and the time is 15~30min. The centrifugation speed is 1500~2000r / min and the time is 3~8min.

[0009] In step (2), the 3D printing ink obtained in step (1) is loaded into the syringe of the direct-write 3D printer. The diameter of the printing needle in the direct-write 3D printer is 300~500μm. The direct-write 3D printer accumulates the 3D printing ink into a three-dimensional structure in three-dimensional space by printing. The moving speed of the printing needle is 8~12mm / s and the gas pressure is 40~60psi.

[0010] In step (3), the printed three-dimensional structure is placed in a refrigerator and frozen for 12 hours, then freeze-dried at -40~-60℃ for 48~72 hours. The dried three-dimensional structure is placed in a crucible, and the crucible is placed in a tube furnace and reduced at 700~1000℃ for 2~6 hours in a high-purity argon atmosphere to obtain the 3D printed silicon-based composite structure material.

[0011] In step (1), the silicene nanosheets are prepared using a topological chemical method, including the following steps: (1) CaSi2 was left to stand in NaOH solution, then filtered and dried to obtain product A; (2) SnCl2 was added to methanol and stirred until completely dissolved to obtain a mixed solution. Product A and sodium dodecylbenzenesulfonate were added to the mixed solution in sequence and stirred. Then the mixture was placed in a constant temperature water bath for reaction. After the reaction was completed, product B was obtained. Product B was washed by centrifugation with methanol and hydrogen chloride methanol solution, filtered and dried under vacuum. Finally, supercritical drying was used to obtain silicene nanosheets.

[0012] The concentration of the NaOH solution is 2 mol / L, and the CaSi2 is allowed to stand in the NaOH solution for 10 min.

[0013] The temperature of the constant temperature water bath was set to 60 ℃, and the reaction time was 24 h.

[0014] Product B was washed three times by centrifugation with methanol and a 5 wt% hydrogen chloride methanol solution, filtered, and vacuum dried at 80 °C for 24 h, and finally supercritical dried for 4 h.

[0015] In step (1), the graphene oxide is prepared using a modified Hummers method, including the following steps: Sodium nitrate, flake graphite powder, and concentrated sulfuric acid were poured into a container and stirred forcibly in an ice-water bath. KMnO4 was then added and stirred. The water bath temperature was increased twice to carry out the reaction. After the reaction was completed, hydrogen peroxide was added and the mixture was allowed to stand. The mixture was then washed with deionized water by centrifugation until it was close to neutral. The mixture was then subjected to ultrasonic and centrifugation to obtain a thick slurry at the bottom. The thick slurry was then freeze-dried in a vacuum freeze dryer to obtain graphene oxide powder, which was then stored under vacuum for later use.

[0016] The water bath temperature is first raised to 35 ℃ and reacted for 45 min, then raised to 90 ℃ and reacted for 15 min.

[0017] The ultrasonic treatment time is 30 min, and the centrifugation time is 15 min.

[0018] The 3D-printed silanene-based composite material prepared above can be used in the preparation of hydrogen storage products, capacitors, and batteries.

[0019] The present invention, employing the above-described structure, can bring the following beneficial effects: (1) Fully utilize the hydrogen storage potential advantages of silicene nanosheets and graphene, and combine them with the rich functional groups on the surface of cellulose nanofibers to form a three-dimensional structure with both hydrogen storage capacity and mechanical properties. At the same time, the three-dimensional structure material has rich continuous layered pores, which can improve the active sites of the composite material and achieve efficient hydrogen storage.

[0020] (2) By adopting 3D printing technology, the preparation process is simple and the structure can be precisely controlled, which has strong practical application value; (3) The 3D printed silene-based composite structure material obtained by the present invention is not only applicable to hydrogen storage, but can also be used as a medium for the adsorption of other gases. Attached Figure Description

[0021] Figure 1 The images show the XRD patterns of the silicene nanosheets, graphene oxide, and 3D-printed silicene-based composite materials of this invention. Figure 2 This is a graph showing the rheological properties of the 3D printing ink of this invention. Figure 3 This is a SEM image of the 3D-printed silicon-based composite structure material of this invention; Figure 4 shows the FT-IR image of the 3D-printed silicon-based composite structure material of the present invention; Figure 5 shows the PCT curve of hydrogen storage of the 3D-printed silene-based composite structure material of the present invention; Figure 6 is a graph showing the hydrogen storage kinetics of the 3D-printed silene-based composite material of the present invention. Detailed Implementation

[0022] To more clearly illustrate the overall concept of the present invention, a detailed description will be provided below with reference to the accompanying drawings and examples.

[0023] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0024] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments. Example 1

[0025] A method for preparing a 3D-printed silicon-based composite structural material includes the following steps: (1) 80 mg of silicene nanosheets and 200 mg of graphene oxide were added sequentially to a 0.5% cellulose nanofiber aqueous solution. Each addition was ultrasonically dispersed (power 200 W, dispersion time 30 min) to obtain a high-concentration fluid. The high-concentration fluid was subjected to planetary degassing and stirring (speed 1500 r / min, time 25 min) and centrifugation (speed 2000 r / min, time 5 min) to finally prepare a uniformly dispersed high-concentration 3D printing ink. (2) Load 3D printing ink into a syringe with a volume of 30 mL; select a printing needle with a diameter of 400 μm; set the printing path (i.e., modeling and slicing, which can be designed according to your own needs), and print the direct-write 3D printer according to the set printing path to obtain a three-dimensional structure made of 3D printing ink (i.e., the three-dimensional structure is determined by the printing path). The printing process is as follows: needle movement speed 10 mm / s, gas pressure 45 psi. (3) Place the printed three-dimensional structure in a refrigerator and freeze for 12 h; then freeze-dry it in a vacuum freeze dryer at -50 ℃ for 60 h; finally, place the dried three-dimensional structure in a crucible and put it in a tube furnace and reduce it at 700 ℃ for 4 h in a high-purity argon atmosphere to obtain the 3D printed silicon-based composite structure material.

[0026] The silicene nanosheets were prepared using a topological chemical method, with the following steps: (1) 1.2 g CaSi2 was placed in 2 mol / L NaOH solution and allowed to stand for 10 min, then filtered and dried to obtain product A; (2) 1.1 g SnCl2 was added to 60 ml methanol and stirred until completely dissolved to obtain a mixed solution. 0.2 g of product A was added to the mixed solution, and sodium dodecylbenzenesulfonate (SDBS) was weighed and added (the amount of SDBS added was 1%~3% of the mass of SnCl2). After stirring, the mixture was placed in a 60 ℃ constant temperature water bath for 24 h. After the reaction was completed, product B was obtained. Product B was washed three times by centrifugation with methanol and 5 wt% hydrogen chloride methanol solution, respectively. The mixture was then filtered and vacuum dried at 80 ℃ for 24 h. Finally, it was supercritically dried for 4 h to obtain silicene nanosheets.

[0027] The graphene oxide was prepared using a modified Hummers method, with the following steps: 2.5 g sodium nitrate, 5 g flake graphite powder, and 115 mL concentrated sulfuric acid were poured into a beaker and stirred for 45 min in an ice-water bath. Then, 15 g KMnO4 was added and stirred for 50 min. The water bath temperature was raised to 35 ℃ and reacted for 45 min. Then, the temperature was raised to 90 ℃ and reacted for 15 min. After the reaction was completed, 25 mL hydrogen peroxide was added and the mixture was allowed to stand for 24 h. The mixture was washed with deionized water by centrifugation until it was nearly neutral. The mixture was ultrasonically dispersed for 30 min and centrifuged for 15 min to obtain a thick slurry at the bottom. The thick slurry was then freeze-dried in a vacuum freeze dryer to obtain graphene oxide powder, which was stored under vacuum for later use. Example 2

[0028] The difference between this embodiment and the above embodiments is that: A method for preparing a 3D-printed silicon-based composite structural material includes the following steps: (1) 100 mg of silicene nanosheets and 200 mg of graphene oxide were added sequentially to a 0.5% cellulose nanofiber aqueous solution. Each addition was ultrasonically dispersed (power 200 W, dispersion time 30 min) to obtain a high-concentration fluid. The high-concentration fluid was then subjected to planetary degassing and stirring (speed 2000 r / min, time 40 min) and centrifuged (speed 2000 r / min, time 10 min) to finally prepare a uniformly dispersed high-concentration 3D printing ink. (2) Load 3D printing ink into a syringe with a volume of 30 mL; select a printing needle with a diameter of 450 μm; set the printing path (the same as the printing path in Example 1); use a direct-write 3D printer to achieve ink deposition in three-dimensional space to obtain a 3D printed three-dimensional structure. The printing process is as follows: needle movement speed 8 mm / s, gas pressure 50 psi. (3) The printed three-dimensional structure was placed in a refrigerator and frozen for 12 h; then it was freeze-dried in a vacuum freeze dryer at -50 ℃ for 72 h; finally, the dried three-dimensional structure was placed in a crucible and placed in a tube furnace and reduced at 700 ℃ for 6 h in a high-purity argon atmosphere to obtain the 3D printed silicon-based composite structure material. Example 3

[0029] A method for preparing a 3D-printed silicon-based composite structural material includes the following steps: (1) 120 mg of silicene nanosheets and 200 mg of graphene oxide were added sequentially to a 1% cellulose nanofiber aqueous solution. Each addition was ultrasonically dispersed (power 200 W, dispersion time 45 min) to obtain a high-concentration fluid. The high-concentration fluid was then subjected to planetary degassing and stirring (speed 2000 r / min, time 45 min) and centrifuged (speed 2500 r / min, time 5 min) to finally prepare a uniformly dispersed high-concentration 3D printing ink. (2) Load 3D printing ink into a syringe with a volume of 30 mL; select a printing needle with a diameter of 500 μm; set the printing path (the same as the printing path in Example 1); use a direct-write 3D printer to achieve ink deposition in three-dimensional space to obtain a 3D printed three-dimensional structure. The printing process is as follows: needle movement speed 10 mm / s, gas pressure 55 psi. (3) Place the printed three-dimensional structure in a refrigerator and freeze for 12 h; then freeze-dry it in a vacuum freeze dryer at -55 ℃ for 72 h; finally, place the dried printed structure in a crucible and put it in a tube furnace and reduce it at 700 ℃ for 6 h in a high-purity argon atmosphere to obtain the 3D printed silicon-based composite structure material. Example 4

[0030] A method for preparing a 3D-printed silicon-based composite structural material includes the following steps: (1) 100 mg of silicene nanosheets and 150 mg of graphene oxide were added sequentially to a cellulose nanofiber aqueous solution with a mass concentration of 1.5%. Each addition was ultrasonically dispersed (power 200 W, dispersion time 30 min) to obtain a high-concentration fluid. The high-concentration fluid was subjected to planetary degassing and stirring (speed 1500 r / min, time 60 min) and centrifuged (speed 2500 r / min, time 10 min) to finally prepare a uniformly dispersed high-concentration 3D printing ink.

[0031] (2) Load 3D printing ink into a syringe with a volume of 30 mL and select a printing needle diameter of 500 μm; set the printing path (the same as the printing path in Example 1), and use a direct-write 3D printer to achieve ink deposition in three-dimensional space to obtain a 3D printed three-dimensional structure. The printing process is as follows: needle movement speed 8 mm / s, gas pressure 60 psi.

[0032] (3) Place the printed three-dimensional structure in a refrigerator and freeze for 12 h; then freeze-dry it in a vacuum freeze dryer at -60 ℃ for 72 h; finally, place the dried three-dimensional structure in a crucible and put it in a tube furnace and reduce it at 1000 ℃ for 4 h in a high-purity argon atmosphere to obtain the 3D printed silicon-based composite structure material.

[0033] To fully verify the technical effectiveness of this method, the above embodiments were carried out, and accompanying drawings are provided for further explanation: from Figure 1 As can be seen, the graphene oxide prepared by the Hummers method in Example 1 only exhibits a significant characteristic peak at 11.4°, proving that the graphite was completely oxidized. The silicene nanosheets prepared by the chemical topological method show four significant characteristic peaks at 17.25°, 28.45°, 47.25°, and 56.1°, indicating that the prepared silicene nanosheets have a high degree of crystallinity. The silicene-based composite material prepared by 3D printing shows a typical characteristic peak of graphite near 26°, indicating that after high-temperature reduction, the graphene oxide was completely reduced to reduced graphene oxide.

[0034] Figure 2 The graph shows the relationship between the apparent viscosity of 3D printing inks and shear rate. As can be seen from the graph, the static apparent viscosity of the 3D printing inks prepared in Examples 1-4 is greater than 105 Pa·s, which meets the requirements of the direct-write extrusion 3D printing technology involved in this invention (generally, the ink viscosity is required to be above 102 Pa·s). At the same time, it was found that the apparent viscosity of all inks gradually decreases with the increase of shear rate. This is a typical characteristic of "non-Newtonian fluid", which can ensure the smooth implementation of the direct-write extrusion 3D printing process.

[0035] Figure 3 Figure (a) is a top view of the 3D-printed silene-based composite structure. It can be seen that the upper and lower layers of the 3D-printed silene-based composite structure are interwoven, the holes between the printed lines are clear, and the structure is very regular. Figure (b) is a SEM image of the lines in the 3D-printed silene-based composite structure. It can be clearly observed from the image that the silene nanosheets and reduced graphene oxide sheets are interwoven, evenly dispersed, and connected by nanofibers. The three of them form a rich hierarchical porous structure. Figure (c) is a SEM image of the lines with a further magnification. Figure (c) further confirms the positional relationship between the silene nanosheets and reduced graphene oxide in Figure (b). It can be seen from the image that the silene nanosheets are covered by a thin layer of reduced graphene oxide, and the two coordinate with each other, which is beneficial to improving the hydrogen storage performance of the structural material.

[0036] Figure 4 The infrared spectrum of the 3D-printed silicene-based composite material is shown. The peak at 3430 cm⁻¹ corresponds to the stretching vibration of -OH; after high-temperature reduction, the stretching vibration peak of -OH essentially disappears. The peaks between 1600 cm⁻¹ and 1620 cm⁻¹ indicate the presence of C=C functional groups in the material, a typical characteristic of reduced graphene oxide. The obvious Si-O-Si peaks at 1050 cm⁻¹ and 1200 cm⁻¹ indicate that partial chemical bonding occurred between the silicene nanosheets and graphene oxide during ink preparation, which is highly beneficial for establishing the internal network of the material and for hydrogen transport between them.

[0037] from Figure 5 As can be seen, the 3D-printed silene-based composite structure material exhibits good hydrogen adsorption-desorption cycle stability, and the hydrogenation of the silene nanosheet surface is a reversible process. Furthermore, the hydrogen storage capacity of the structure material gradually increases with the increase of the proportion of silene nanosheets in the material. The 3D-printed silene-based composite structure material can achieve a hydrogen storage performance of 2.5 wt% at room temperature, with a high hydrogen adsorption rate and good hydrogen storage effect.

[0038] from Figure 6 As can be seen, under room temperature conditions, all 3D printed silanene-based composite materials exhibit a relatively fast hydrogen adsorption rate; comparative analysis shows that the composite material corresponding to Example 4 has the highest hydrogen adsorption rate.

[0039] The above specific embodiments should not be construed as limiting the scope of protection of the present invention. For those skilled in the art, any alternative improvements or modifications made to the embodiments of the present invention shall fall within the scope of protection of the present invention.

[0040] Any aspects of this invention not described in detail are well-known to those skilled in the art.

Claims

1. A method for preparing a 3D-printed silicon-based composite structural material, characterized in that, Includes the following steps: (1) Add silicene nanosheets and graphene oxide to a cellulose nanofiber aqueous solution in sequence. The mass concentration of the cellulose nanofiber aqueous solution is 0.5~1.5%. The mass ratio of silicene nanosheets, graphene oxide and cellulose nanofiber aqueous solution is 1~2:1~5:100~130. Each addition is ultrasonically dispersed to obtain a high-concentration fluid suitable for 3D printing. The high-concentration fluid is subjected to planetary degassing and centrifugation to obtain 3D printing ink. (2) Using the 3D printing ink obtained in step (1), a three-dimensional structure is printed using a direct-write 3D printer; (3) The three-dimensional structure printed in step (2) is freeze-dried and reduced at a high temperature of 700~1000℃ to prepare a silicon-based composite structure material.

2. The method for preparing a 3D printed silicon-based composite structural material according to claim 1, characterized in that, In step (1), the ultrasonic dispersion power is 200W and the dispersion time is 30min. The planetary degassing and stirring speed is 1500~2000r / min and the time is 15~30min. The centrifugation speed is 1500~2000r / min and the time is 3~8min.

3. The method for preparing a 3D printed silicon-based composite structural material according to claim 2, characterized in that, In step (2), the 3D printing ink obtained in step (1) is loaded into the syringe of the direct-write 3D printer. The diameter of the printing needle in the direct-write 3D printer is 300~500μm. The direct-write 3D printer accumulates the 3D printing ink into a three-dimensional structure in three-dimensional space by printing. The moving speed of the printing needle is 8~12mm / s and the gas pressure is 40~60psi.

4. The method for preparing a 3D printed silicon-based composite structural material according to claim 3, characterized in that, In step (3), the printed three-dimensional structure is placed in a refrigerator and frozen for 12 hours, then freeze-dried at -40~-60℃ for 48~72 hours. The dried three-dimensional structure is placed in a crucible, and the crucible is placed in a tube furnace and reduced at 700~1000℃ for 2~6 hours in a high-purity argon atmosphere to obtain the 3D printed silicon-based composite structure material.

5. The method for preparing a 3D printed silicon-based composite structural material according to claim 1, characterized in that, In step (1), the silicene nanosheets are prepared using a topological chemical method, including the following steps: (1) CaSi2 was left to stand in NaOH solution, then filtered and dried to obtain product A; (2) SnCl2 was added to methanol and stirred until completely dissolved to obtain a mixed solution. Product A and sodium dodecylbenzenesulfonate were added to the mixed solution in sequence and stirred. Then the mixture was placed in a constant temperature water bath for reaction. After the reaction was completed, product B was obtained. Product B was washed by centrifugation with methanol and hydrogen chloride methanol solution, filtered and dried under vacuum. Finally, supercritical drying was used to obtain silicene nanosheets.

6. The method for preparing a 3D-printed silicon-based composite structural material according to claim 5, characterized in that, The concentration of the NaOH solution was 2 mol / L. The CaSi2 was allowed to stand in the NaOH solution for 10 min. The temperature of the constant temperature water bath was set to 60 ℃. The reaction time was 24 h. The product B was washed three times by centrifugation with methanol and a 5 wt% hydrogen chloride methanol solution, respectively. It was then filtered and vacuum dried at 80 ℃ for 24 h, and finally supercritical dried for 4 h.

7. A method for preparing a 3D-printed silicon-based composite structural material according to claim 1 or 5, characterized in that, In step (1), the graphene oxide is prepared using a modified Hummers method, including the following steps: Sodium nitrate, flake graphite powder, and concentrated sulfuric acid were poured into a container and stirred forcibly in an ice-water bath. KMnO4 was then added and stirred. The water bath temperature was increased twice to carry out the reaction. After the reaction was completed, hydrogen peroxide was added and the mixture was allowed to stand. The mixture was then washed with deionized water by centrifugation until it was close to neutral. The mixture was then subjected to ultrasonic and centrifugation to obtain a thick slurry at the bottom. The thick slurry was then freeze-dried in a vacuum freeze dryer to obtain graphene oxide powder, which was then stored under vacuum for later use.

8. The method for preparing a 3D-printed silicon-based composite structural material according to claim 7, characterized in that, The water bath temperature is first raised to 35 ℃ and reacted for 45 min, then raised to 90 ℃ and reacted for 15 min. The ultrasonic treatment time is 30 min, and the centrifugation treatment is 15 min.

9. The application of the 3D-printed silanene-based composite structural material prepared by the preparation method according to any one of claims 1-8, characterized in that, The 3D-printed silanene-based composite material is used in the preparation of hydrogen storage products, capacitors, and batteries.

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