阅读说明：本技术 石墨烯气凝胶三维结构及其制备方法 (Graphene aerogel three-dimensional structure and preparation method thereof ) 是由 李文博 刘静 刘丹阳 王佳伟 李静 李炯利 *** 于 2019-09-27 设计创作，主要内容包括：本发明涉及一种石墨烯气凝胶三维结构及其制备方法,该制备方法包括：获取柔性模具；将功能材料墨水注入柔性模具,冷冻成型,将所得冰层转印到基底上,获得第1层冰层；重复上步骤,在第1层冰层上逐层转印上N层冰层,获得N+1层堆叠冰层,N≥0；N+1层堆叠冰层中,至少有一层冰层采用的功能材料墨水包含有氧化石墨烯或/和石墨烯；对所述N+1层堆叠冰层进行干燥；或者,对所述N+1层堆叠冰层进行干燥、还原。该方法能够简单、高效的制备形状复杂的石墨烯气凝胶三维结构,有利于石墨烯气凝胶三维结构规模化制造；该制备方法具有丰富的材料适用性,石墨烯气凝胶三维结构的尺寸可在大的范围内进行调整。(The invention relates to a graphene aerogel three-dimensional structure and a preparation method thereof, wherein the preparation method comprises the following steps: obtaining a flexible mold; injecting functional material ink into a flexible mould, freezing and forming, and transferring the obtained ice layer to a substrate to obtain a layer 1 ice layer; repeating the above steps, and transferring N ice layers on the 1 st ice layer by layer to obtain N +1 stacked ice layers, wherein N is more than or equal to 0; in the N +1 stacked ice layers, at least one layer of ice layer adopts functional material ink containing graphene oxide or/and graphene; drying the N +1 stacked ice layers; or, drying and reducing the N +1 stacked ice layers. The method can simply and efficiently prepare the graphene aerogel three-dimensional structure with a complex shape, and is beneficial to large-scale manufacture of the graphene aerogel three-dimensional structure; the preparation method has rich material applicability, and the size of the three-dimensional structure of the graphene aerogel can be adjusted in a large range.)

1. The preparation method of the graphene aerogel three-dimensional structure is characterized by comprising the following steps:

step one, obtaining a mould;

injecting functional material ink into the mold, freezing and molding, and then transferring to obtain a layer 1 ice layer;

step three, repeating the step two, and transferring N ice layers on the layer 1 ice layer by layer to obtain N +1 stacked ice layers, wherein N is more than or equal to 0; in the N +1 stacked ice layers, at least one layer of ice layer adopts functional material ink containing graphene oxide or/and graphene;

step four, drying the N +1 stacked ice layers; or, drying and reducing the N +1 stacked ice layers.

2. The method for preparing the three-dimensional structure of the graphene aerogel according to claim 1, wherein in the second step, the conditions for freeze forming comprise: the temperature is-80 ℃ to-20 ℃, and the time is 0.5h to 24 h.

3. The preparation method of the three-dimensional structure of the graphene aerogel according to claim 1 or 2, wherein in the third step, the functional material ink adopted by at least one ice layer is graphene oxide or/and graphene aqueous dispersion, or graphene oxide or/and graphene and composite material A aqueous dispersion; the composite material A is selected from one or more of carbon nano tubes, nano metal particles, nano metal oxides, metal nano wires, two-dimensional nano materials and conductive molecules.

4. The method for preparing the graphene aerogel three-dimensional structure according to claim 3, wherein the nano metal particles are one or more selected from silver nanoparticles, gold nanoparticles and platinum nanoparticles; or/and the nano metal oxide is selected from nano Fe₃O₄TiO 2 nanoparticles₂And nano MnO₂One or more of the above; or/and the metal nano-wire is selected from one or more of silver nano-wire, copper nano-wire and gold nano-wire; or/and the two-dimensional nano material is selected from MoS₂、BN、Ti₃C₂And Ti₄N₃One or more of the above; or/and, thereforeThe conductive molecules are selected from one or more of polyaniline, polypyrrole and polythiophene.

5. The preparation method of the graphene aerogel three-dimensional structure according to claim 3, wherein in the functional material ink, the concentration of the graphene oxide or/and the graphene is 1 mg/mL-30 mg/mL; or/and the mass ratio of the graphene oxide or/and graphene to the composite material A is not more than 1: 1.

6. The preparation method of the graphene aerogel three-dimensional structure according to claim 1 or 2, wherein the functional material ink adopted by at least one ice layer in the N +1 stacked ice layers comprises an aqueous solution of a water-soluble polymer, or/and an aqueous dispersion of the water-soluble polymer and a composite material B; the water-soluble polymer is selected from one or more of polyvinyl alcohol, sodium alginate, polyacrylamide and nano-cellulose; the composite material B is selected from one or more of carbon nano tubes, nano metal particles, nano metal oxides, metal nano wires, two-dimensional nano materials and conductive molecules.

7. The preparation method of the graphene aerogel three-dimensional structure according to claim 6, wherein the concentration of the water-soluble polymer is 1mg/mL to 60 mg/mL; and/or the ratio of the mass of the water-soluble polymer to the mass of the composite material B is not more than 1: 1.

8. The preparation method of the graphene aerogel three-dimensional structure according to claim 6, wherein the nano metal particles are selected from one or more of silver nanoparticles, gold nanoparticles and platinum nanoparticles; or/and the nano metal oxide is selected from nano Fe₃O₄TiO 2 nanoparticles₂And nano MnO₂One or more of the above; or/and the metal nano-wire is selected from one or more of silver nano-wire, copper nano-wire and gold nano-wire; or/and the two-dimensional nano material is selected from MoS₂、BN、Ti₃C₂And Ti₄N₃One or more of the above; or/and the conductive molecules are selected from one or more of polyaniline, polypyrrole and polythiophene.

9. The method for preparing a graphene aerogel three-dimensional structure according to claim 6, wherein the N +1 stacked ice layers have an alternating structure; the functional material ink adopted by one ice layer forming the alternating structure comprises graphene oxide or/and graphene, and the functional material ink adopted by the other ice layer is an aqueous solution of a water-soluble polymer or/and an aqueous dispersion of the water-soluble polymer and a composite material B.

10. The method for preparing the three-dimensional structure of the graphene aerogel according to claim 1 or 2, wherein in the fourth step, the drying is freeze-drying, or/and the reduction is thermal reduction or reduction with a reducing agent.

11. The method for preparing the graphene aerogel three-dimensional structure according to claim 10, wherein the freeze-drying time is 1-72 hours; or/and the conditions of the thermal reduction comprise: the temperature is 200-3000 ℃, and the time is 1-24 h; or/and the reducing agent is hydrazine hydrate or hydroiodic acid.

12. Graphene aerogel three-dimensional structure obtained by the preparation method of any one of claims 1 to 11.

Technical Field

The invention relates to the technical field of graphene materials, in particular to a graphene aerogel three-dimensional structure and a preparation method thereof.

Background

The graphene aerogel is a three-dimensional macroscopic body material which is constructed by two-dimensional graphene and has an interconnected porous network structure, and is also called graphene foam, graphene sponge or graphene macroscopic body. The graphene aerogel not only has the structural characteristics of aerogel with low density, high specific surface area, high elasticity, high porosity and heat insulation performance, but also has excellent physical and chemical properties of graphene, has good electric and thermal conductivity and excellent mechanical strength, and can be compositely modified with other functional molecules or units through physical and chemical effects. The characteristics lead the material to have wide application prospect in the fields of energy absorption, heat insulation, pollutant adsorption, catalytic carriers, flexible sensors, energy storage electrode materials, electromagnetic shielding and the like.

The method for manufacturing the graphene aerogel three-dimensional structure mainly comprises a reduction assembly method, a direct freeze-drying method and a 3D printing method. The reduction assembly method is to induce graphene oxide to aggregate into graphene hydrogel through hydrothermal or chemical reduction, and form the three-dimensional graphene aerogel after removing the solvent in the hydrogel network. The direct freeze-drying method is to directly freeze-dry a graphene oxide dispersion liquid or a compound with certain size characteristics to form the three-dimensional graphene aerogel. The 3D printing method comprises the steps of extruding high-concentration ink containing graphene oxide through a needle head, forming a three-dimensional shape under the control of a three-dimensional moving platform, and freeze-drying to form the three-dimensional graphene aerogel.

Aerogels prepared by reductive assembly and direct freeze-drying methods are generally simple block structures, which are limited mainly by the shape of the container used in the preparation. Wherein, the reduction assembly has larger volume shrinkage, and the structure is not easy to be controlled accurately. And due to the special mechanical properties of aerogel materials, the process of material reduction manufacturing similar to the traditional materials is difficult to meet. 3D prints the advantage that has the flexibility in the complex structure preparation, but need satisfy 3D printing's technological adaptability with the ink material of high glutinous high concentration, but the material type, the density etc. that make the three-dimensional structure of graphene aerogel printed out receive the restriction because of printable material's limitation. And the problem that the structure is difficult to maintain due to ink drying may exist in the process of 3D printing of large-size complex structures, and the whole processing range is limited. In addition, the layer-by-layer extrusion printing mode is not beneficial to large-scale manufacturing in the aspects of processing speed and efficiency.

Therefore, a simple and efficient preparation method of the graphene aerogel three-dimensional structure is urgently needed to be developed.

Disclosure of Invention

Based on the above, the main purpose of the present invention is to provide a preparation method of a graphene aerogel three-dimensional structure. The preparation method is simple and efficient, and the graphene aerogel three-dimensional structure is prepared in a freezing auxiliary transfer mode.

The purpose of the invention is realized by the following technical scheme:

the invention provides a preparation method of a graphene aerogel three-dimensional structure, which comprises the following steps:

step one, obtaining a mould;

injecting functional material ink into the mold, freezing and molding, and then transferring to obtain a layer 1 ice layer;

step three, repeating the step two, and transferring N ice layers on the layer 1 ice layer by layer to obtain N +1 stacked ice layers, wherein N is more than or equal to 0; in the N +1 stacked ice layers, at least one layer of ice layer adopts functional material ink containing graphene oxide or/and graphene;

step four, drying the N +1 stacked ice layers; or, drying and reducing the N +1 stacked ice layers.

In one embodiment, in step two, the conditions of the freeze-forming include: the temperature is-80 ℃ to-20 ℃, and the time is 0.5h to 24 h.

In one embodiment, in the third step, the functional material ink adopted by at least one ice layer is graphene oxide or/and graphene aqueous dispersion, or graphene oxide or/and graphene and composite material a aqueous dispersion; the composite material A is selected from one or more of carbon nano tubes, nano metal particles, nano metal oxides, metal nano wires, two-dimensional nano materials and conductive molecules.

In one embodiment, the nano metal particles are selected from one or more of silver nanoparticles, gold nanoparticles and platinum nanoparticles; or/and the nano metal oxide is selected from nano Fe₃O₄TiO 2 nanoparticles₂And nano MnO₂One or more of the above; or/and the metal nano-wire is selected from one or more of silver nano-wire, copper nano-wire and gold nano-wire; or/and the two-dimensional nano material is selected from MoS₂、BN、Ti₃C₂And Ti₄N₃One or more of the above; or/and the conductive molecules are selected from one or more of polyaniline, polypyrrole and polythiophene.

In one embodiment, in the functional material ink, the concentration of the graphene oxide or/and the graphene is 1 mg/mL-30 mg/mL; or/and the mass ratio of the graphene oxide or/and graphene to the composite material A is not more than 1: 1.

In one embodiment, the functional material ink adopted by at least one ice layer in the N +1 stacked ice layers comprises an aqueous solution of a water-soluble polymer or/and an aqueous dispersion of the water-soluble polymer and the composite material B; the water-soluble polymer is selected from one or more of polyvinyl alcohol, sodium alginate, polyacrylamide and nano-cellulose; the composite material B is selected from one or more of carbon nano tubes, nano metal particles, nano metal oxides, metal nano wires, two-dimensional nano materials and conductive molecules.

In one embodiment, the concentration of the water-soluble polymer is 1 mg/mL-60 mg/mL; and/or the ratio of the mass of the water-soluble polymer to the mass of the composite material B is not more than 1: 1.

In one embodiment, the nano metal particles are selected from one or more of silver nanoparticles, gold nanoparticles and platinum nanoparticles; or/and the nano metal oxide is selected from nano Fe₃O₄TiO 2 nanoparticles₂And nano MnO₂One or more of the above; or/and the metal nano-wire is selected from one or more of silver nano-wire, copper nano-wire and gold nano-wire; or/and the two-dimensional nano material is selected from MoS₂、BN、Ti₃C₂And Ti₄N₃One or more of the above; or/and the conductive molecules are selected from one or more of polyaniline, polypyrrole and polythiophene.

In one embodiment, the N +1 stacked ice layers have an alternating structure; the functional material ink adopted by one ice layer forming the alternating structure comprises graphene oxide or/and graphene, and the functional material ink adopted by the other ice layer is an aqueous solution of a water-soluble polymer or/and an aqueous dispersion of the water-soluble polymer and a composite material B.

In one embodiment, in the fourth step, the drying is freeze drying, or/and the reduction is thermal reduction or reduction with a reducing agent.

In one embodiment, the freeze drying time is 1-72 h; or/and the conditions of the thermal reduction comprise: the temperature is 200-3000 ℃, and the time is 1-24 h; or/and the reducing agent is hydrazine hydrate or hydroiodic acid.

The invention also aims to provide a graphene aerogel three-dimensional structure obtained by the preparation method.

Compared with the prior art, the invention has the following beneficial effects:

the method comprises the steps of preparing a graphene aerogel three-dimensional structure in a freezing auxiliary transfer mode, specifically, taking a flexible mold as a printing plate, injecting nano functional material ink containing graphene oxide or/and graphene into the flexible mold, freezing and molding, transferring an obtained ice layer onto a substrate to obtain a single-layer ice layer, or repeating the operation, continuously transferring the ice layer on the single-layer ice layer to obtain a multi-layer stacked ice layer, and drying the single-layer ice layer or the multi-layer stacked ice layer, or reducing the single-layer ice layer or the multi-layer stacked ice layer after drying. The method can simply and efficiently prepare the graphene aerogel three-dimensional structure with the complex shape, and is beneficial to large-scale manufacturing of the graphene aerogel three-dimensional structure. In addition, the preparation method has rich material applicability, and the size of the three-dimensional structure of the graphene aerogel can be adjusted in a large range.

Drawings

Fig. 1 is a structural diagram of a three-dimensional network graphene oxide aerogel prepared in example 1;

fig. 2 is a structural diagram of a three-dimensional network graphene oxide aerogel prepared in example 2;

fig. 3 is a structural diagram of a three-dimensional network graphene oxide aerogel prepared in example 3;

FIG. 4 is a schematic flow diagram of a manufacturing process of the present invention;

fig. 5 is a comparison graph of the graphene aerogel with the agglomeration phenomenon and the graphene aerogel with the regular morphology, the left graph is the graphene aerogel with the agglomeration phenomenon, and the right graph is the graphene aerogel with the regular morphology.

Detailed Description

In order that the invention may be more fully understood, reference will now be made to the following description. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The embodiment provides a preparation method of a graphene aerogel with a three-dimensional structure, which includes the following steps:

step one, obtaining a mold.

The mold used in this step is usually a flexographic plate as a printing plate for transfer printing. The flexible mold facilitates removal after transfer during manufacture and facilitates maintaining the structural integrity of the transferred material.

In one embodiment, the mold may be obtained by 3D printing, for example, a 3D printer is used to prepare a resin mold with a specific convex shape, an elastomer material is poured into the mold, and after curing, the resin mold is removed to obtain a flexible mold with a groove as a transfer printing plate. It is clear to the person skilled in the art that the manner of obtaining the flexible mould is not limited thereto. The specific convex shapes described in this embodiment are any pattern of dots, lines, planes, arrays, or combinations thereof. The elastomer material described in this embodiment is any one of room temperature vulcanized silicone rubber, polydimethylsiloxane, Ecoflex, and polyurethane elastomer. Of course, it is clear to the person skilled in the art that the elastomeric material is not limited thereto.

And step two, injecting functional material ink into the flexible mold, freezing and molding, and then transferring the obtained ice layer to a substrate to obtain a layer 1 ice layer.

The transfer operation of the present embodiment includes: and adhering the obtained ice layer on a substrate, and removing the flexible mould after the ice layer is adhered to the substrate, so that the ice layer is transferred to the substrate.

In one embodiment, the substrate is glass. It is to be understood that the kind of the substrate is not limited thereto.

Step three, repeating the step two, and transferring N ice layers on the layer 1 ice layer by layer to obtain N +1 stacked ice layers, wherein N is more than or equal to 0; in the N +1 stacked ice layers, at least one layer of ice layer adopts functional material ink containing graphene oxide or/and graphene.

The layer-by-layer transfer operation of the embodiment comprises the steps of obtaining the 1 st ice layer, then pasting another layer of flexible mold containing a frozen ice layer on the previous ice layer, and after the two ice layers are adhered, removing the flexible mold, and transferring to obtain the two stacked ice layers. Repeating the transfer printing process to obtain a multi-layer stacked ice layer. In each transfer process, the functional material ink injected may be the same material or different material. In each transfer process, the flexible dies used can be flexible dies with the same structure or flexible dies with different structures. The flexible mold with the ice layer can be changed by any angle in the horizontal direction during each transfer. See fig. 4.

In one embodiment, the conditions of the freeze-forming include: the temperature is-80 ℃ to-20 ℃, and the time is 0.5h to 24 h. By selecting the freezing and forming conditions, the physical state of the nano functional material ink can be changed into a solid state, more importantly, the formed ice crystals can extrude graphene or graphene oxide in the nano functional material ink into a honeycomb arrangement structure, then the ice crystals are sublimated through freezing and drying, and the graphene or the graphene oxide is assembled into the porous graphene aerogel with the regular morphology.

In one embodiment, in the third step, the functional material ink adopted by at least one ice layer is graphene oxide or/and graphene aqueous dispersion, or graphene oxide or/and graphene and composite material a aqueous dispersion; the composite material A is selected from carbon nano-tube, nano-metal particle (such as silver nano-particle, gold nano-particle, platinum nano-particle, etc.), nano-metal oxide (such as nano Fe)₃O₄TiO 2 nanoparticles₂Nano MnO of₂Etc.), metal nanowires (e.g., silver nanowires, copper nanowires, gold nanowires, etc.), two-dimensional nanomaterials (e.g., MoS)₂、BN、Ti₃C₂、Ti₄N₃Etc.) and conductive molecules (e.g., polyaniline, polypyrrole, polythiophene, etc.).

In one embodiment, the concentration of the graphene oxide or/and the graphene is 1 mg/mL-30 mg/mL.

In one embodiment, the concentration of the graphene oxide or/and the graphene is 2 mg/mL-10 mg/mL.

In one embodiment, the ratio of the mass of the graphene oxide or/and graphene to the mass of the nanocomposite material a does not exceed 1: 1.

In one embodiment, the functional material ink adopted by at least one ice layer in the N +1 stacked ice layers comprises an aqueous solution of a water-soluble polymer or/and an aqueous dispersion of the water-soluble polymer and the composite material B; the water-soluble polymer is selected from one or more of polyvinyl alcohol, sodium alginate, polyacrylamide and nano-cellulose; the composite material B is selected from carbon nano-tubes, nano-metal particles (such as silver nano-particles, gold nano-particles, platinum nano-particles and the like), nano-metal oxides (such as nano Fe)₃O₄TiO 2 nanoparticles₂Nano MnO of₂Etc.), metal nanowires (e.g., silver nanowires, copper nanowires, gold nanowires, etc.), two-dimensional nanomaterials (e.g., MoS)₂、BN、Ti₃C₂、Ti₄N₃Etc.) and conductive molecules (e.g., polyaniline, polypyrrole, polythiophene, etc.).

In one embodiment, the concentration of the water-soluble polymer is 1mg/mL to 60mg/mL, and the ratio of the mass of the water-soluble polymer to the mass of the composite material B is not more than 1: 1.

In one embodiment, the concentration of the water-soluble polymer is 5mg/mL to 50 mg/mL.

In one embodiment, the N +1 stacked ice layers have an alternating structure; the functional material ink adopted by one ice layer forming the alternating structure comprises graphene oxide or/and graphene, and the functional material ink adopted by the other ice layer is an aqueous solution of a water-soluble polymer or/and an aqueous dispersion of the water-soluble polymer and a composite material B.

Step four, drying the N +1 stacked ice layers; or, drying and reducing the N +1 stacked ice layers.

In one embodiment, if the functional material ink does not contain graphene oxide, the N +1 stacked ice layers are dried without reduction; if the functional material ink contains graphene oxide, the N +1 stacked ice layers need to be reduced after being dried. It is understood that the reduction may be thermal or chemical. If thermal reduction is employed, conditions include: the temperature is 200-3000 ℃, and the time is 1-24 h. If chemical reduction is used, the reducing agent used may be hydrazine hydrate or hydroiodic acid.

In one embodiment, the drying is freeze drying, and the drying time is 1-72 h.

The embodiment also provides a graphene aerogel with a three-dimensional structure, which is obtained by the preparation method.