Nanometer mesh material and preparation method thereof

Abstract

The invention belongs to the field of porous materials, and particularly relates to a nano mesh material and a preparation method thereof. The preparation method comprises the following steps: providing a porous membrane; the pore channels of the porous membrane are filled with a body material at the temperature ranging from 0.5 Tm to 0.8 Tm, the composite material is obtained, Tm is the melting point of the body material, and the body material comprises a metal material or a semiconductor material; and removing the porous membrane in the composite material to obtain the nano mesh material. According to the preparation method, the material selection flexibility is greatly improved, and meanwhile, the thickness, the aperture and the porosity of the nano mesh material are accurately controlled.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of porous materials, and particularly relates to a nanomesh material and a preparation method thereof. BACKGROUND

[0002] The related art for preparing the nanomesh material is to melt or mechanically mix the target metal material and a sacrificial material according to a certain ratio, and then to selectively dissolve the sacrificial material in an acid or alkaline solution by dealloying, so as to leave a three-dimensionally connected porous metal skeleton. This technology is limited by the selection and compatibility of available alloy elements, because dealloying usually removes active metal elements, and certain metals may not be suitable for this preparation method, which limits the material selection of the structure of the nanomesh material, and the thickness, pore size and porosity of the nanomesh material are difficult to adjust secondarily once set, and cannot meet the demand for gradient pores. Therefore, one of the challenges is to develop a preparation method that can flexibly select the target metal material and accurately control the thickness, pore size and porosity of the nanomesh material. SUMMARY

[0003] The present application aims to at least partially solve one of the technical problems in the related art. To this end, the present application proposes a nanomesh material and a preparation method thereof, which greatly improves the flexibility of material selection while accurately controlling the thickness, pore size and porosity of the nanomesh material.

[0004] In a first aspect of the present application, a method for preparing a nanomesh material is provided, which comprises: providing a porous membrane; filling a bulk material into the pores of the porous membrane at a temperature of 0.5Tm-0.8Tm, to obtain a composite material, Tm being the melting point of the bulk material, the bulk material comprising a metal material or a semiconductor material; removing the porous membrane in the composite material to obtain a nanomesh material. Thus, this method effectively avoids the pore defects caused by the gas retention at the end of the pores due to the use of the molten state to fill the pores of the porous membrane in the related art. At the same time, the low atomic migration rate under the solid-state diffusion condition significantly inhibits the interfacial reaction between the metal and the template material at high temperature, thereby helping to ensure the purity of the final nanomesh material. This method can also independently adjust the template parameters of the porous membrane, accurately control the thickness, pore size and porosity of the nanomesh material, and more importantly, this method is compatible with a variety of metals, breaking the limitation of the traditional dealloying method on the material, greatly improving the flexibility of material selection and application potential.

[0005] According to an embodiment of the present application, the filling process satisfies at least one of the following conditions: the pressure of the filling process is 200 MPa-500 MPa; the temperature of the filling process is 200℃-700℃; the duration of the filling process is 1 min-60 min. Thus, the suitable pressure helps to drive the bulk material to achieve the dense filling of the pores in the form of atomic diffusion. The appropriate temperature can provide the activation energy required for atomic diffusion, so that the filling process can be efficiently completed. The suitable duration can ensure that the atomic migration of the bulk material fully covers the depth of the pores, so that the pores are more completely filled.

[0006] According to an embodiment of the present application, at least one of the following conditions is satisfied: the metal material comprises at least one of lead, silver, gold, copper, platinum, nickel, titanium; the semiconductor material comprises at least one of bismuth telluride, silver telluride, tin selenide. Thus, the applicable metal material and semiconductor material are widely used, covering materials from low melting point to high melting point, breaking the limitation of material compatibility in traditional methods, and greatly expanding the selection range of the bulk material.

[0007] According to an embodiment of the present application, the porous membrane comprises a porous alumina membrane. Thus, the porous alumina template has high mechanical strength and is not easy to collapse; its preparation process and raw material cost are relatively low, and it shows good chemical inertness to most metal materials and is not easy to cause interface reaction.

[0008] According to an embodiment of the present application, the providing of the porous alumina membrane comprises: depositing an aluminum film on a substrate; anodizing the aluminum film with the aluminum film as an anode to obtain the porous alumina membrane. Thus, this step is more simple and convenient, and the cost is lower; and the obtained porous alumina membrane has the support of the substrate, has better mechanical strength, and the pores are more uniform.

[0009] According to an embodiment of the present application, the anodizing satisfies at least one of the following conditions: the voltage of the anodizing is 30 V-70 V; the oxidation time of the anodizing is 5 min-120 min, and the electrolyte of the anodizing comprises at least one of oxalic acid, phosphoric acid, and sulfuric acid. Thus, the appropriate anodizing voltage can generate pores with uniform pore size, and the pore structure will be more ordered; the appropriate oxidation time can form a porous alumina membrane with a suitable thickness; and the above-mentioned electrolyte of the anodizing helps to generate a porous alumina membrane with a suitable pore size and porosity.

[0010] According to an embodiment of the present application, the pores of the porous alumina membrane are three-dimensionally connected. Thus, the three-dimensionally connected pore structure can increase the specific surface area of the pores, and at the same time, the mutual support between the pore walls can also increase the mechanical stability of the porous alumina membrane.

[0011] According to an embodiment of the present application, the porous alumina film is obtained by etching the porous alumina film. In this way, the pore size of the porous alumina film can be further enlarged, and the specific surface area of the pore channel of the porous alumina film is larger.

[0012] According to an embodiment of the present application, the etching is phosphoric acid immersion. In this way, phosphoric acid is a weak acid, and the reaction is relatively mild.

[0013] According to an embodiment of the present application, the mass fraction of phosphoric acid in the etching is 1wt.%-10wt.%, and the etching time is 1min-120min. In this way, within the above range, the pore size structure of the porous alumina film can be maintained intact while further enlarging the pore size.

[0014] According to an embodiment of the present application, the porous film in the composite material is removed by an etching method. The etching method can be at least one of pickling and alkaline cleaning. In this way, the selectivity is high, the nano-network material is not damaged, and the etching method is simple and low in cost.

[0015] In a second aspect of the present application, a nano-network material is provided, which is prepared according to the method described above. The nano-network material involves related substances and parameters consistent with the preparation method of the nano-network material described above, which will not be repeated here.

[0016] According to an embodiment of the present application, the nano-network material satisfies at least one of the following conditions: the pore size of the pore channel in the nano-network material is 10nm-300nm; and the porosity of the nano-network material is 20%-80%. In this way, the pore size of the nano-network material covers a wide range, and can be applied to different fields as needed. The appropriate porosity has high flux and good mechanical properties at the same time, and can be widely used in the fields of catalysis, sensing, energy storage and conversion, electronic devices, and flexible electronics. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The flow chart of the preparation method of the nano-network material is an embodiment of the present application.

[0018] Figure 2 The cross-sectional morphology schematic diagram of the porous film in Embodiment 1 of the present application is shown.

[0019] Figure 3 The top morphology schematic diagram of the composite material in Embodiment 1 of the present application is shown.

[0020] Figure 4 The cross-sectional morphology schematic diagram of the nano-network material structure in Embodiment 2 of the present application is shown.

[0021] Figure 5is the stress-strain curve of the nanomesh material micropillar of embodiment 2 of the present application.

[0022] Figure 6 is a schematic diagram of the cross-sectional morphology of the composite material of embodiment 3 of the present application.

[0023] Reference signs: 1-porous membrane; 2-substrate; 3-bulk material. DETAILED DESCRIPTION

[0024] The embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0025] At present, the related technology for preparing nanomesh materials is to melt or mechanically mix the target metal material with the sacrificial material in a certain ratio, and then use the dealloying method to selectively dissolve the sacrificial material in an acid or alkaline solution, leaving a three-dimensionally connected porous metal skeleton. On the one hand, this process is limited by the selection and compatibility of available alloy materials, because dealloying usually preferentially dissolves the active metal components, and certain metal systems may not be suitable for this preparation method, limiting the material selection range of nanomesh materials. On the other hand, the molten state casting relies on capillary force to fill the pores of the porous membrane template. However, the high surface tension of the molten metal at high temperature, the poor wettability of the template, and the softening of the template material all contribute to the easy collapse of the pore walls. At the same time, gas retention at the end of the pore causes pores, resulting in incomplete or uneven filling.

[0026] The present application gradually and uniformly fills the pore space by atomic diffusion and plastic deformation of the filled material in a solid state under stress driving within the temperature range of 0.5Tm-0.8Tm. This method effectively avoids the pore defects caused by gas retention at the end of the pore. At the same time, the low atomic migration rate under solid-state diffusion conditions significantly inhibits the interfacial reaction between the metal and the template material at high temperature, thereby helping to ensure the purity of the final nanomesh material. This method can also independently adjust the parameters of the porous membrane template, accurately control the thickness, pore size and porosity of the nanomesh material; more importantly, this method breaks through the material compatibility limitation in related technologies, greatly improving the flexibility of material selection.

[0027] Based on the above, the first aspect of the present application provides a method for preparing a nanomesh material, the method comprising the following steps:

[0028] S10: providing a porous membrane, the structural schematic diagram is referred to Figure 1 (a) in the figure.

[0029] It can be understood that the porous membrane as a template of the nanometer network material provides an accurate morphology control benchmark for the structure of the final product. The pore size, shape, porosity and connectivity of the porous membrane directly determine the structural characteristics of the final nanometer network material.

[0030] According to the embodiments of the present application, the porous membrane comprises a porous alumina membrane. Thus, the porous alumina template has high mechanical strength and is not easy to collapse; the preparation process and raw material cost are low, and it shows good chemical inertness to most metal materials and semiconductor materials, and is not easy to cause interface reaction.

[0031] According to the embodiments of the present application, the porous alumina membrane is provided by depositing an aluminum membrane on a substrate, and anodizing the aluminum membrane with the aluminum membrane as an anode to obtain the porous alumina membrane. Thus, this step is more simple and convenient, and the cost is lower; and the obtained porous alumina membrane has the support of the substrate, and has better mechanical strength.

[0032] According to the embodiments of the present application, the substrate includes but is not limited to a silicon wafer. Thus, the substrate material is resistant to high temperature and has good support performance.

[0033] According to the embodiments of the present application, the aluminum membrane can also include an aluminum membrane containing a doping element, and the doping element includes but is not limited to a Cu element. Thus, the doping of the Cu element helps to form a porous membrane that penetrates horizontally and vertically in the anodizing process.

[0034] According to the embodiments of the present application, the doping concentration of the doping element is 0.02%-1.00%, specifically 0.02%, 0.05%, 0.10%, 0.20%, 0.40%, 0.50%, 0.75%, 1.00% or any range between any two of them. Thus, within the above-mentioned doping concentration range, it is helpful to form a stable porous membrane. If the doping concentration is too high, the pore size is too large, causing the structure to collapse; if the doping concentration is too low, it will be difficult to form a three-dimensional porous network that penetrates horizontally and vertically.

[0035] According to the embodiments of the present application, before depositing the aluminum membrane on the substrate, it further includes: washing the substrate in advance, and the cleaning solvent includes at least one of deionized water and ethanol, specifically, the present application uses deionized water and ethanol for washing in sequence. Thus, the impurities on the surface of the substrate can be washed away, which is beneficial to better deposition of the aluminum membrane subsequently.

[0036] According to the embodiments of the present application, the deposition method for depositing the aluminum membrane on the substrate includes at least one of magnetron sputtering and thermal evaporation aluminum plating. As an embodiment of the present application, the magnetron sputtering method is used to deposit the aluminum membrane. Thus, the magnetron sputtering can accurately control the composition of the deposition and the deposition is more uniform, and it is easier to form a dense aluminum membrane.

[0037] According to embodiments of the present application, the annealing process is performed at a temperature of 300-500°C, specifically, 300°C, 350°C, 400°C, 450°C, 500°C, or a range between any two of them. In this way, the appropriate annealing temperature can effectively eliminate the stress of the aluminum film, ensuring that the aluminum film remains flat and firmly attached to the substrate during the subsequent anodization process, thereby achieving high-quality anodization. Too high an annealing temperature can cause the aluminum film to easily form an aluminum oxide layer, resulting in peeling or bubbling of the aluminum film; too low an annealing temperature can result in residual stress.

[0038] According to embodiments of the present application, the annealing process is performed for a time of 4-8h, specifically, 4h, 5h, 6h, 7h, 8h, or a range between any two of them. In this way, within the above-mentioned time range for annealing, the stress of the aluminum film can be completely eliminated. Too long a time can weaken the bonding force between the substrate and the aluminum film, making the aluminum film prone to peeling; too short a time can result in incomplete stress elimination, making the aluminum film prone to cracking or peeling during subsequent anodization.

[0039] It can be understood that after annealing is completed, the aluminum film needs to be anodized to generate a layer of porous aluminum oxide film on the surface of the aluminum film, which can serve as a template for the subsequent filling process. During anodization, the pore size and porosity of the porous aluminum oxide film template can be controlled by adjusting the anodization voltage and time, thereby precisely controlling the thickness, pore size, and porosity of the nanomesh material.

[0040] According to embodiments of the present application, the anodization voltage is 30-70V, specifically, 30V, 35V, 40V, 45V, 50V, 55V, 60V, 65V, 70V, or a range between any two of them. In this way, an appropriate anodization voltage can generate pores with uniform pore size, and the pore structure will also be more ordered. If the voltage is too high, the local pore wall can collapse; if the voltage is too low, the driving force for anodization can be insufficient, causing the pores to become disordered.

[0041] According to embodiments of the present application, the anodization oxidation time is 5-120min, specifically, 5min, 10min, 20min, 40min, 60min, 80min, 100min, 110min, 120min, or a range between any two of them. In this way, an appropriate oxidation time can form a porous aluminum oxide film with an appropriate thickness and integrity. Too short an oxidation time can result in insufficient film thickness, making it prone to breakage; too long an oxidation time can also not significantly increase the film thickness, resulting in wasted time.

[0042] According to embodiments of the present application, the electrolyte for anodization includes at least one of oxalic acid, phosphoric acid, and sulfuric acid. In some embodiments, oxalic acid can be used as the electrolyte for anodization. Thereby, it is helpful to generate a porous alumina film with a suitable pore size and porosity.

[0043] According to embodiments of the present application, the pores of the porous alumina film are three-dimensionally connected. Thereby, the three-dimensionally connected pore structure can increase the specific surface area of the pores, while the mutual support between the pore walls also increases the mechanical stability of the porous alumina film.

[0044] According to embodiments of the present application, the obtaining the porous alumina film further includes etching the porous alumina film. Thereby, the pore size of the porous alumina film can be further enlarged, and the specific surface area of the pores of the porous alumina film can be further increased.

[0045] According to embodiments of the present application, the etching includes at least one of phosphoric acid immersion and sulfuric acid immersion. In some embodiments, phosphoric acid immersion can be used. Thereby, phosphoric acid is a weak acid, and the reaction is relatively mild.

[0046] According to embodiments of the present application, the mass fraction of phosphoric acid in the etching is 1wt.%-10wt.%, specifically 1wt.%, 2wt.%, 3wt.%, 4wt.%, 5wt.%, 6wt.%, 7wt.%, 8wt.%, 9wt.%, 10wt.%, or a range between any two of them. Thereby, within the above range, the pore size structure of the porous alumina film can be kept intact while its pore size is further enlarged. If the concentration of phosphoric acid is too high, excessive etching can occur, causing the pore structure to collapse; if the concentration of phosphoric acid is too low, the pore size of the porous alumina film will not be significantly affected.

[0047] According to embodiments of the present application, the etching time is 1min-120min, specifically 1min, 10min, 20min, 40min, 60min, 80min, 100min, 120min, or a range between any two of them. Thereby, within the above time range, it is helpful to further enlarge the pore size of the porous alumina film and increase its specific surface area. If the etching time is too long, the pore structure of the porous alumina film can be eroded, damaging its structural integrity; if the etching time is too short, the effect of enlarging the pore size of the porous alumina film can be limited.

[0048] As a specific example, a porous aluminum film is deposited on a substrate using a magnetron sputtering technique. After deposition is complete, it is placed in a vacuum environment and annealed at 300-500°C for 4-8h. Then, the annealed porous aluminum film is used as an anode, and an oxalic acid solution is used as an electrolyte to perform anodic oxidation at a voltage of 30-70V for 5-120min to obtain a porous aluminum oxide film. The porous aluminum oxide film is immersed in a 1-10wt.% phosphoric acid solution for 1-120min to further expand the pores of the porous aluminum oxide film.

[0049] S20: The bulk material is filled into the pores of the porous film at a temperature of 0.5Tm-0.8Tm to obtain a composite material, and a structural schematic diagram is shown in Figure 1 (b) of FIG. 1, and Figure 1 (c) of FIG. 1. Tm is the melting point of the bulk material, which includes a metal material or a semiconductor material.

[0050] In this step, at a medium-high temperature range of 0.5Tm-0.8Tm, the metal material or the semiconductor material is filled into the pores of the porous aluminum oxide film in the form of atomic migration driven by solid-state stress diffusion. In this way, the pore collapse and porosity defects of the traditional melting method are completely avoided, and the interface side reaction is simultaneously inhibited, thereby realizing a complete composite material structure with high purity and high specific surface area. In addition, this method is compatible with a variety of metals, breaking the limitations of traditional de-alloying methods and greatly improving the flexibility of material selection and application potential.

[0051] According to an embodiment of the present application, the pressure of the filling process is 200-500MPa, specifically 200MPa, 250MPa, 300MPa, 350MPa, 400MPa, 450MPa, 500MPa, or a range between any two of them. In this way, the above pressure range helps to drive the bulk material to achieve dense filling of the pores in the form of atomic diffusion. If the pressure is too high, it may cause the template pore wall to be extruded and deformed or cracked, and if the pressure is too low, it may cause the filling to stop due to insufficient diffusion driving force, resulting in incomplete pore filling.

[0052] According to an embodiment of the present application, the temperature of the filling process is 200-700°C, specifically 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, or a range between any two of them. In this way, the appropriate temperature can provide the activation energy required for atomic diffusion, so that the filling process can be efficiently completed. If the temperature is too high, it may cause an interface reaction between the pore wall of the porous aluminum oxide film and the bulk material; if the temperature is too low, it may significantly reduce the diffusion rate, affecting the efficiency of the filling process.

[0053] According to embodiments of the present application, the duration of the filling process is 1 min-60 min, specifically 1 min, 5 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min or any range between any two of them. Thus, the appropriate duration can ensure that the atomic migration of the bulk material sufficiently covers the depth of the pores, making the pore filling more complete. If the time is too short, it can lead to the end of the pore not being filled; if the time is too long, it can not significantly improve the filling effect, causing waste of time.

[0054] According to embodiments of the present application, the metal material includes at least one of lead, silver, gold, copper, platinum, nickel, titanium; the semiconductor material includes at least one of bismuth telluride, silver telluride, tin selenide. Thus, the optional filling material is widely available and can be applied to most metal materials and semiconductor materials.

[0055] As a specific example, the bulk material is placed on the porous alumina film, and the bulk material is filled into the pores of the porous alumina film to form a composite material at a temperature of 200-700°C, under a pressure of 200-500 MPa, for a filling time of 1-60 min.

[0056] S30: removing the porous film in the composite material to obtain a nanometer network material, the structural schematic diagram is referred to Figure 1 (d) in FIG.

[0057] In this step, the porous film is removed, leaving only the bulk material originally filled in the pores of the porous film, to obtain a nanometer network material composed of a three-dimensional network. Thus, this step is simple and easy to implement, and selectively removes the porous film without damaging the nanometer network material.

[0058] According to embodiments of the present application, the removal of the porous film in the composite material is carried out by an etching method; in some embodiments, the etching method includes at least one of acid washing and alkali washing. Thus, the selectivity is high and the nanometer network material is not damaged, and the above etching method is simple and low in cost.

[0059] According to embodiments of the present application, the etching substance used in the etching method includes at least one of sulfuric acid aqueous solution, phosphoric acid aqueous solution, mixed aqueous solution of phosphoric acid and chromic acid, potassium hydroxide aqueous solution, sodium hydroxide aqueous solution, and in some embodiments, phosphoric acid aqueous solution can be used for etching. In other embodiments, potassium hydroxide aqueous solution can be used for etching. Thus, when the prepared nanometer network material is resistant to acid corrosion, the porous film is removed by acid washing; when the prepared nanometer network material is resistant to alkali corrosion, the porous film is removed by alkali washing, which has high selectivity and does not damage the nanometer network material; and the reaction is mild and does not generate intense heat, so that the etching rate inside and outside the pores is consistent.

[0060] According to embodiments of the present application, the concentration of the acidic solution used in the acid washing is 0.3 mol·L -1 - 6 mol·L -1 . Specifically, 0.3 mol·L -1 , 1 mol·L -1 , 2 mol·L -1 , 3 mol·L -1 , 4 mol·L -1 , 5 mol·L -1 , 6 mol·L -1 , or a range between any two of them. Thus, within the above concentration range, it helps to remove the porous film more efficiently. If the concentration of the acidic solution is too high, it can corrode the skeleton of the nanomesh material structure, causing excessive corrosion; if the concentration of the acidic solution is too low, the porous film can not be completely removed, affecting the subsequent application of the nanomesh material.

[0061] According to embodiments of the present application, the concentration of the basic solution used in the alkali washing is 0.3 mol·L -1 - 6 mol·L -1 . Specifically, 0.3 mol·L -1 , 1 mol·L -1 , 2 mol·L -1 , 3 mol·L -1 , 4 mol·L -1 , 5 mol·L -1 , 6 mol·L -1 , or a range between any two of them. Thus, within the above concentration range, it helps to remove the porous film more efficiently. If the concentration of the basic solution is too high, it can corrode the skeleton of the nanomesh material structure, causing excessive corrosion; if the concentration of the basic solution is too low, the porous film can not be completely removed, affecting the application of the nanomesh material.

[0062] According to embodiments of the present application, the corrosion time is 1 h-12 h. Specifically, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, or a range between any two of them. Thus, within the above time range, it helps to remove the porous film more thoroughly. If the corrosion time is too long, it can corrode the skeleton of the nanomesh material, destroying the integrity of its structure; if the corrosion time is too short, the porous film can not be completely removed, affecting the application of the nanomesh material.

[0063] As a specific example, the composite material is immersed in an acidic solution or a basic solution, soaked for 1 h-12 h, and the porous film is removed to obtain a nanomesh material.

[0064] In a second aspect, the present application provides a nanomesh material prepared according to the method described above. The nanomesh material involves related substances and parameters consistent with the preparation method of the nanomesh material described above, which will not be repeated here.

[0065] According to embodiments of the present application, the pore size of the nanomesh material is 10 nm-300 nm, specifically, 10 nm, 20 nm, 50 nm, 80 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, or any range between any two of them. Thus, the nanomesh material has a wide range of pore sizes and can be applied in different fields as needed.

[0066] According to embodiments of the present application, the porosity of the nanomesh material is 20%-80%, specifically, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or any range between any two of them. Thus, the appropriate porosity can have high flux while maintaining good mechanical properties, and can be widely used in catalysis, sensing, energy storage and conversion, electronic devices, and flexible electronics.

[0067] Example 1

[0068] First, the silicon wafer was cleaned with deionized water and ethanol in turn, and then a 5 μm thick aluminum film doped with 0.5 wt% copper elements was deposited on the cleaned silicon wafer using a magnetron sputtering technique. After deposition, the silicon wafer with aluminum film was placed in a vacuum environment and annealed at 400°C for 6h. Then, the annealed silicon wafer with aluminum film was used as an anode, 3M oxalic acid solution was used as an electrolyte, and platinum was used as a cathode, and an anodic oxidation was carried out at a constant voltage of 40V, with an oxidation duration of 30min. The reaction endpoint was determined by real-time monitoring of the current change. When a sharp decrease in current was observed (indicating that the aluminum film had formed a porous structure), the anodic oxidation process was terminated, and a porous aluminum oxide film was obtained. To further expand the pores of the porous aluminum oxide film, the porous aluminum oxide film was immersed in a 5 wt.% phosphoric acid solution for 20min to further expand the pores of the porous aluminum oxide film.

[0069] The bulk material lead sheet was placed on the porous aluminum oxide film, and a pressure of 200MPa and a temperature of 200°C were applied, with a filling time of 2 minutes, so that the lead diffused into the pores of the porous aluminum oxide film to form a composite material. Then, the obtained composite material was subjected to etching treatment, and the composite material was immersed in a 0.3 mol·L -1 of aqueous phosphoric acid solution for 0.5h to etch and remove the porous aluminum oxide film, and finally obtain a nanomesh lead material.

[0070] Example 2

[0071] The same as example 1, except that the bulk material used is silver flake, and the resulting composite is immersed in 3 mol·L -1 of aqueous potassium hydroxide solution for 0.5 h to etch away the porous alumina film and obtain a nanomesh silver material.

[0072] Example 3

[0073] The same as example 1, except that the bulk material used is semiconductor Bi2Te3, and the resulting composite is immersed in 3 mol·L -1 of aqueous phosphoric acid solution for 3 h to etch away the porous alumina film and obtain a nanomesh Bi2Te3 material.

[0074] Performance test method

[0075] Stress-strain curve test method: The porous silver obtained in example 2 is subjected to stress-strain curve test, and is processed by focused ion beam (FIB) processing technology (beam current: 1 nA, acceleration voltage: 30 kV, minimizing Ga + ion damage to the surface of the column) to prepare a porous silver microcolumn with a diameter of about 3 μm. Subsequently, in-situ compression test is performed using a Pi 88 nanoindenter system (Hysitron Inc.) in a scanning electron microscope (SEM, Zeiss Sigma 300). In the test, the sample platform is tilted by 10° for real-time imaging, and a flat indenter with a diameter of about 10 μm is used for displacement-controlled loading at a constant rate of 20 nm·s -1 . The test results are plotted, from which the yield strength value is read, where the yield strength refers to the stress value corresponding to the point at which the stress-strain curve deviates from linear elastic behavior and produces a specified small permanent plastic deformation during the stress process.

[0076] The test results are shown in Figure 5 , which show that the yield strength of the porous silver microcolumn is more than 220 MPa, while the yield strength of bulk silver is only ~ 100 MPa (the yield strength data of bulk silver is from the literature: S. Buzzi aet. al. Philosophical Magazine, 2009). In other words, the yield strength of the porous silver can reach about 2.3 times the strength of bulk silver, which is significantly better than the strength of bulk silver.

[0077] In the description of the specification, the description using the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the particular feature, structure, material or characteristic being described is included in at least one embodiment or example of the present application. The illustrative appearances of the above-mentioned terms in various places in the specification are not necessarily referred to the same embodiment or example. Moreover, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples. Furthermore, the description herein of certain examples does not necessarily exclude these features, structures, materials or characteristics from being used in other examples. Neither can such description imply that these features, structures, materials or characteristics are essential to the practice of the application.

[0078] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be interpreted as limiting the present application, and that variations, modifications, substitutions and changes can be made by those skilled in the art without departing from the scope of the present application.

Claims

1. A method for preparing nanostructured network materials, characterized in that, include: Provide porous membranes; At a temperature of 0.5Tm to 0.8Tm, the bulk material is filled into the pores of the porous membrane to obtain a composite material, where Tm is the melting point of the bulk material, which includes metallic or semiconductor materials. The porous membrane in the composite material is removed to obtain a nanomesh material.

2. The method according to claim 1, characterized in that, At least one of the following conditions must be met: The filling pressure is 200MPa-500MPa; The filling temperature is 200℃-700℃; The filling duration is 1 min to 60 min.

3. The method according to claim 1, characterized in that, At least one of the following conditions must be met: The metallic material includes at least one of lead, silver, gold, copper, platinum, nickel, and titanium; The semiconductor material includes at least one of bismuth telluride, silver telluride, and tin selenide.

4. The method according to claim 1, characterized in that, The porous membrane includes a porous alumina membrane.

5. The method according to claim 4, characterized in that, The provision of the porous alumina film includes: Deposit an aluminum film on a substrate; Using the aluminum film as the anode, the aluminum film is anodized to obtain the porous alumina film.

6. The method according to claim 5, characterized in that, At least one of the following conditions must be met: The voltage for anodizing is 30V-70V; The oxidation time for the anodizing is 5 min to 120 min; The electrolyte for anodic oxidation includes at least one of oxalic acid, phosphoric acid, and sulfuric acid.

7. The method according to claim 5, characterized in that, The porous alumina membrane has three-dimensionally interconnected pores.

8. The method according to claim 5, characterized in that, The process of obtaining the porous alumina film further includes etching the porous alumina film.

9. The method according to claim 8, characterized in that, The etching method includes phosphoric acid immersion.

10. The method according to claim 9, characterized in that, At least one of the following conditions must be met: The mass fraction of phosphoric acid in the etching process is 1 wt.% to 10 wt.%. The etching time is 1 min to 120 min.

11. The method according to claim 1, characterized in that, The porous membrane in the composite material was removed by an etching method; Preferably, the corrosion method includes at least one of acid washing and alkaline washing.

12. A nanostructured mesh material, characterized in that, Prepared according to the method described in claims 1-11.

13. The nanostructured material according to claim 12, characterized in that, At least one of the following conditions must be met: The pore size of the channels in the nanomesh material is 10nm-300nm; The porosity of the nanomesh material is 20%-80%.

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