Aerogel material with enhanced mechanical property as well as preparation method and application of aerogel material

Abstract

The invention is suitable for the technical field of aerogel, and discloses a mechanical property enhanced aerogel material, a preparation method and application thereof, and a thermoelectric device. The aerogel material with the enhanced mechanical property comprises nanowire aerogel and a polymer coating layer, the exterior of the nanowire aerogel is coated with the polymer coating layer, and the polymer coating layer is a nanoscale polymer coating layer. According to the aerogel material with the enhanced mechanical property, due to the fact that the exterior of the nanowire aerogel is coated with the macromolecule coating layer, the mechanical property of the material is improved and enhanced, the thermoelectric performance of the material is protected, and therefore the mechanical property of the aerogel material with the enhanced mechanical property is improved. And the thermoelectric property and the mechanical property are relatively good.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aerogel, in particular to a kind of aerogel material with enhanced mechanical properties and its preparation method and application, and a kind of thermoelectric device. BACKGROUND

[0002] With the rapid development of flexible electronic devices, there is an increasing demand for materials that have both high thermoelectric performance and mechanical flexibility. Although organic thermoelectric materials such as PEDOT:PSS and PANI have good flexibility, their thermoelectric figure of merit (zT) is generally less than 0.1, which cannot meet the energy harvesting requirements. Although the introduction of inorganic nanomaterials such as Bi2Te3 and PbTe into organic / inorganic composite materials can partially improve the performance, the low electrical conductivity of the organic matrix and the problem of phase separation limit the improvement of zT value (e.g., the zT value of PEDOT:PSS-based aerogel is only 0.01). Three-dimensional network structure materials such as aerogel have become a research hotspot due to their ultra-low thermal conductivity (0.015 W / mK) and high porosity, but the synergistic optimization of their thermoelectric performance and mechanical properties still faces challenges. SUMMARY

[0003] The present application aims to provide an aerogel material with enhanced mechanical properties and its preparation method and application, and a kind of thermoelectric device, which solves the technical problem of poor mechanical performance of existing aerogels.

[0004] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0005] The first aspect of the present application provides an aerogel material with enhanced mechanical properties, which comprises a nanowire aerogel and a polymer coating layer coated on the outside of the nanowire aerogel, and the polymer coating layer is a nanoscale polymer coating layer.

[0006] In one embodiment, the polymer coating layer is any one of a polyimide coating layer, a polyurethane coating layer, a polyvinyl alcohol coating layer and a polyamide coating layer.

[0007] And / or, the nanowire aerogel is Ag nanowire aerogel or Ag2Se nanowire aerogel.

[0008] In one embodiment, the thickness of the polymer coating layer is 2 nm to 20 nm.

[0009] Preferably, the thickness of the polymer coating layer is 10 nm to 20 nm.

[0010] The second aspect of the present application provides a preparation method of an aerogel material, which is the aerogel material with enhanced mechanical properties of the first aspect described above, and the preparation method comprises:

[0011] A nanowire aerogel is provided;

[0012] A polymer coating layer is coated on the outside of the nanowire aerogel to obtain the aerogel material.

[0013] In one embodiment, the polymer coating layer coated on the outside of the nanowire aerogel comprises:

[0014] The nanowire aerogel is immersed in a polymer precursor solution and gradiently heated and solidified to form a polymer coating layer on the outside of the nanowire aerogel.

[0015] In one embodiment, the mass ratio of the nanowire aerogel to the polymer precursor solution is 1:100, and the mass fraction of the polymer precursor solution is 3% to 30%.

[0016] In one embodiment, the polymer precursor solution is prepared by dissolving any one of PMDA-ODA, PPG-TDI, PVA, and PA-DET in a solvent.

[0017] Preferably, the solvent is dimethylacetamide or dimethylformamide.

[0018] In one embodiment, the polymer precursor solution is prepared by dissolving PMDA-ODA in a solvent.

[0019] The gradiently heating and solidifying comprises: pre-solidifying at 70°C to 90°C for 0.5h to 1.5h, and then heating to 150°C to 250°C for imidization for 1.5h to 2.5h.

[0020] The third aspect of the present application provides a thermoelectric device comprising a thermoelectric generator prepared from the mechanically enhanced aerogel material of the first aspect.

[0021] The fourth aspect of the present application provides an application of the mechanically enhanced aerogel material of the first aspect in the field of thermoelectric conversion.

[0022] Due to the above technical solutions, the present application has the advantages that: by coating a polymer coating layer on the outside of the Ag2Se nanowire aerogel, the polymer coating layer bridges the nanocrystalline boundaries through hydrogen bonds and van der Waals forces, which can improve the compressive strength and bending flexibility of the material. The polymer coating layer selectively covers the non-conductive interface, preserves the carrier transport channel, ensures the electrical conductivity of the material, and the low thermal conductivity further inhibits the conduction of phonons. The polymer coating layer improves the mechanical properties of the material, so that the mechanical properties of the material are enhanced, and the thermoelectric properties of the material are protected. Therefore, the mechanically enhanced aerogel material provided by the present application can enhance the mechanical properties of the material while protecting the thermoelectric properties of the material. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 Schematic diagrams and corresponding TEM images of the Ag2Se@PI aerogel and Ag2Se nanowire aerogel prepared in Example 1;

[0024] Figure 2 SEM images of Ag2Se@PI aerogel prepared in Examples 1-3, Ag@PI aerogel prepared in Example 4, Ag nanowire aerogel and Ag2Se nanowire aerogel.

[0025] Figure 3 The thermoelectric performance parameters of Ag2Se@PI aerogel and Ag2Se nanowire aerogel prepared in Example 1 are shown in the figure.

[0026] Figure 4 The resistance change curve of Ag2Se@PI aerogel prepared in Example 1 after 100 bends;

[0027] Figure 5 This is a picture of the Ag2Se@PI aerogel prepared in Example 1 during bending tests.

[0028] Figure 6 Stress-strain curves of Ag2Se@PI aerogel prepared in Example 1 under different strain cycles (20%, 30%, 40%, 50%, 60%, 70%).

[0029] Figure 7 The stress and resistance changes of the Ag2Se@PI aerogel prepared in Example 1 after 1000 cycles at a strain of 40% are shown in the figure.

[0030] Figure 8 Stress-strain curves of Ag2Se@PI aerogel, Ag nanowire aerogel and Ag2Se nanowire aerogel prepared in Examples 1-3 at a strain of 40%. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings. In the following embodiments, many details are described to facilitate a better understanding of the present application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other materials or methods. In some cases, certain operations related to the present application are not shown or described in the specification. This is to avoid obscuring the core parts of the present application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; the relevant operations can be fully understood based on the description in the specification and general technical knowledge in the art.

[0032] In addition, features described in the specification, operations or characteristics can be combined in any appropriate manner to form various embodiments. Meanwhile, the steps or actions in the method description can also be sequentially changed or adjusted in a manner that can be apparent to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment, and do not mean that the sequence is necessary, unless otherwise stated that a certain sequence must be followed.

[0033] The first aspect of the present application provides a mechanical performance enhanced aerogel material, comprising a nanowire aerogel and a polymer coating layer coated on the outside of the nanowire aerogel, wherein the polymer coating layer is a nanoscale polymer coating layer.

[0034] It should be noted that by coating a polymer coating layer on the outside of the nanowire aerogel, the polymer coating layer bridges the nanocrystalline grain boundaries through hydrogen bonds and van der Waals forces, which can improve the compressive strength and bending flexibility of the material, wherein the compressive strength can reach more than 0.9 kPa, and the bending flexibility is more than 1000 cycles without fracture. And the polymer coating layer selectively covers the non-conductive interface, leaving the carrier transport channel, ensuring the electrical conductivity of the material, and the low thermal conductivity (0.01 W / mK-0.1 W / mK) further inhibits the conduction of phonons. The polymer coating layer improves the mechanical properties of the material, so that the mechanical properties of the material are enhanced, and the thermoelectric properties of the material are protected. Therefore, the mechanical performance enhanced aerogel material provided by the present application protects the thermoelectric properties of the material, while having better mechanical properties.

[0035] In an embodiment, the polymer coating layer is any one of a polyimide (PI) coating layer, a polyurethane (PU) coating layer, a polyvinyl alcohol (PVA) coating layer, and a polyamide (PA) coating layer.

[0036] It should be noted that PI has excellent tensile strength of more than 400 MPa and anisotropic thermal expansion coefficient, and by using a PI coating layer to coat the nanowire aerogel, the obtained aerogel material not only retains the high thermoelectric properties of the nanowire aerogel, but also improves the flexibility of the aerogel material, forming a solid and deformable nanowire network structure.

[0037] In an embodiment, the nanowire aerogel is an Ag nanowire aerogel or an Ag2Se nanowire aerogel. It can be understood that in other embodiments, the nanowire aerogel can also be other aerogels.

[0038] It should be noted that when the nanowire aerogel is an Ag2Se nanowire aerogel, the polymer coating layer bridges the Ag2Se nanocrystal boundaries through hydrogen bonds and van der Waals forces, which can improve the compressive strength and bending flexibility of the material. In the Ag2Se nanowire aerogel skeleton, electrons can be effectively transmitted through the conductive Ag2Se, and phonons are scattered at the grain boundaries. The Ag2Se nanowire aerogel has high electrical performance and low thermal conductivity, and the overall thermoelectric figure of merit is high, so that the aerogel material has high electrical performance, low thermal conductivity, and high thermoelectric figure of merit.

[0039] In an embodiment, the thickness of the polymer coating layer is 2 nm to 20 nm. In specific applications, the thickness of the polymer coating layer can be 2 nm, 5 nm, 7 nm, 10 nm, 13 nm, 15 nm, 18 nm, or 20 nm, etc. Preferably, the thickness of the polymer coating layer is 10 nm to 20 nm. By setting the thickness of the polymer coating layer to 2 nm to 20 nm, the basic porosity of the aerogel does not change, and the thin layer of polymer can achieve good mechanical property strengthening effect. If the thickness of the polymer is too large, it may cause the aerogel to weaken the recovery, increase the hardness, and cause uneven coating.

[0040] The second aspect of the present application provides a preparation method of an aerogel material, the aerogel material being the mechanically enhanced aerogel material of the first aspect described above, and the preparation method comprising:

[0041] Step S-10, providing a nanowire aerogel;

[0042] Step S-20, coating a polymer coating layer on the outside of the nanowire aerogel to obtain the aerogel material.

[0043] It should be noted that by coating a polymer coating layer on the outside of the nanowire aerogel, the polymer coating layer bridges the nanocrystal boundaries through hydrogen bonds and van der Waals forces, which can improve the compressive strength and bending flexibility of the material. And the polymer coating layer selectively covers the non-conductive interface, preserves the carrier transport channel, ensures the electrical conductivity of the material, and the low thermal conductivity (0.01 W / mK to 0.1 W / mK) further inhibits the conduction of phonons. The polymer coating layer improves the mechanical properties of the material and protects the thermoelectric properties of the material.

[0044] In an embodiment, the coating of the polymer coating layer on the outside of the nanowire aerogel comprises:

[0045] immersing the nanowire aerogel in a polymer precursor solution, and gradient temperature curing to form a polymer coating layer on the outside of the nanowire aerogel.

[0046] It should be noted that the nanoscale polymer coating layer is formed on the surface of the nanowire aerogel through the dipping-curing process. The process is simple and easy to operate.

[0047] In an embodiment, the mass ratio of the nanowire aerogel and the polymer precursor solution is 1:100, and the mass fraction of the polymer precursor solution is 3% to 30%.

[0048] It should be noted that by setting the mass ratio of the nanowire aerogel and the polymer precursor solution to 1:100, the aerogel material has better mechanical properties and good compression resistance. When the amount of the polymer precursor solution is too high, a large amount of polymer will be enriched, resulting in non-uniform coating and destruction of the structure of the material. When the amount of the polymer precursor solution is too low, the coating will not be complete, resulting in uneven structure and unstable mechanical properties. By setting the mass fraction of the polymer precursor solution to 3% to 30%, the thickness of the coating layer can be 2nm to 20nm.

[0049] In an embodiment, the polymer precursor solution is prepared by dissolving any one of PMDA-ODA (Pyromellitic Dianhydride / 4,4'-diaminodiphenyl ether), PPG-TDI (Polyether polyol / Toluene diisocyanate), PVA (Polyvinyl alcohol), and PA-DET (Adipic acid-diethylamine) in a solvent; preferably, the solvent is dimethylacetamide or dimethylformamide.

[0050] It should be noted that when the polymer precursor solution is prepared by dissolving PMDA-ODA in dimethylacetamide, the polymer coating layer is a PI coating layer. When the polymer precursor solution is prepared by dissolving PA-DET in dimethylacetamide, the polymer coating layer is a PA coating layer. When the polymer precursor solution is prepared by dissolving PVA in dimethylacetamide, the polymer coating layer is a PVA coating layer. When the polymer precursor solution is prepared by dissolving PPG-TDI in dimethylacetamide, the polymer coating layer is a PU coating layer.

[0051] When the nanowire aerogel is an Ag2Se nanowire aerogel and the polymer coating layer is a PI coating layer, high electrical conductivity (10-100 S / cm), high Seebeck coefficient (-100- -150 μV / K) and ultra-low thermal conductivity (0.018-0.075 W / mK) are realized through the synergistic effect of the continuous network of Ag2Se nanocrystals and the PI coating, and the room-temperature zT value reaches 0.15-0.26, thereby realizing a breakthrough in thermoelectric performance. Moreover, the PI coating can increase the compressive strength of the aerogel material to 0.9 kPa (the uncoated sample does not rebound), can withstand a compression strain of >40% and repeated bending (curvature radius of 5 mm, resistance change of <5% after 1000 cycles), and greatly improves the mechanical properties, thereby meeting the dynamic deformation requirements of wearable devices.

[0052] In an embodiment, the polymer precursor solution is prepared by dissolving PMDA-ODA in a solvent.

[0053] The gradient temperature curing includes: pre-curing at 70-90℃ for 0.5-1.5h, and then imidizing at 150-250℃ for 1.5-2.5h.

[0054] The third aspect of the present application provides a thermoelectric device including a thermoelectric generator prepared from the mechanically enhanced aerogel material of the first aspect.

[0055] It should be noted that the thermoelectric generator prepared from the mechanically enhanced aerogel material of the first aspect has better mechanical properties and better compressive strength.

[0056] The fourth aspect of the present application provides an application of the mechanically enhanced aerogel material of the first aspect in the field of thermoelectric conversion.

[0057] The mechanically enhanced aerogel material provided by the present application has the following beneficial effects:

[0058] 1) The polymer coating improves the mechanical stability: the in-situ coating of the plastic polymer polyimide does not affect the thermoelectric performance while greatly improving the mechanical stability of the material;

[0059] 2) High process compatibility: the temperature for curing the polymer coating layer is not higher than 200℃, so the entire process is suitable for roll-to-roll large-scale production, and the PI coating process can be integrated into the existing aerogel production line;

[0060] 3) Expand environmental adaptability: the PI coating layer endows the material with moisture resistance (performance retention rate >95% under 85% humidity) and high temperature resistance (structure stable at 200℃), expanding the application scenarios of the material.

[0061] The application will be further described in detail below through specific examples. The following examples are only for further illustrating the application and should not be understood as limiting the application. It should be noted that, unless otherwise specified, the reagents, instruments and the like used in the examples are all commercially available.

[0062] Example 1

[0063] Step S-10, providing Ag2Se nanowire aerogel;

[0064] Step S-20, immersing 0.1 g of Ag2Se nanowire aerogel into 10 g of 5% PMDA-ODA dimethylacetamide solution (PMDA-ODA is prepared by dissolving in dimethylacetamide), pre-curing at 80°C for 1 h, then imidizing at 200°C for 2 h to form a nanoscale PI coating layer, thereby obtaining an aerogel material, i.e., Ag2Se@PI aerogel (Ag2Se@PI aerogel).

[0065] In this embodiment, the thickness of the PI coating layer of the prepared Ag2Se@PI aerogel is 10 nm, and the error of the thickness of the PI coating layer is within ±2 nm.

[0066] In order to distinguish the Ag2Se@PI aerogel prepared in this embodiment from the Ag2Se@PI aerogels prepared in Examples 2 and 3, the Ag2Se@PI aerogel in this embodiment is named as Ag2Se@PI-1 aerogel (Ag2Se@PI-1 aerogel).

[0067] Example 2

[0068] Step S-10, providing Ag2Se nanowire aerogel;

[0069] Step S-20, immersing 0.1 g of Ag2Se nanowire aerogel into 10 g of 10% PMDA-ODA dimethylacetamide solution (PMDA-ODA is prepared by dissolving in dimethylacetamide), pre-curing at 80°C for 1 h, then imidizing at 200°C for 2 h to form a nanoscale PI coating layer, thereby obtaining an aerogel material, i.e., Ag2Se@PI aerogel (Ag2Se@PI aerogel).

[0070] In this embodiment, the thickness of the PI coating layer of the prepared Ag2Se@PI aerogel is 15 nm, and the error of the thickness of the PI coating layer is within ±2 nm.

[0071] In order to distinguish the Ag2Se@PI aerogel prepared in this embodiment from the Ag2Se@PI aerogels prepared in Examples 1 and 3, the Ag2Se@PI aerogel in this embodiment is named as Ag2Se@PI-2 aerogel (Ag2Se@PI-2 aerogel).

[0072] Example 3

[0073] Step S-10, providing Ag2Se nanowire aerogel;

[0074] Step S-20, immersing 0.1 g of Ag2Se nanowire aerogel into 10 g of 15% PMDA-ODA dimethylacetamide solution (PMDA-ODA is prepared by dissolving in dimethylacetamide), pre-curing at 80°C for 1 h, then imidizing at 200°C for 2 h, forming a nanoscale PI coating layer, obtaining an aerogel material, namely Ag2Se@PI aerogel.

[0075] In this embodiment, the thickness of the PI coating layer of the Ag2Se@PI aerogel prepared is 20 nm, and the error of the thickness of the PI coating layer is within ±3 nm.

[0076] In order to distinguish the Ag2Se@PI aerogel prepared in Examples 1 and 2, the Ag2Se@PI aerogel of this embodiment is named as Ag2Se@PI-3 aerogel.

[0077] Example 4:

[0078] Different from Example 1, the nanowire aerogel is Ag nanowire aerogel. The aerogel material of this embodiment is called Ag@PI aerogel.

[0079] Example 5:

[0080] Different from Example 1, when the polymer precursor solution is prepared by dissolving PA-DET in dimethylacetamide, the polymer coating layer coated by the Ag2Se nanowire aerogel is a PA coating layer.

[0081] Test:

[0082] TEM images were obtained using a JEM-2100F JEOL at 200 kV. SEM images were observed on a MIRA-LMH II (TESKAN) equipped with an EDS detector. Cyclic electrical and stress tests were performed in situ by an electronic mechanical testing machine (AGX-V, SHIMADU, Japan) equipped with a 100N sensor with a precision of ±0.3%.

[0083] The electrical conductivity (σ) and Seebeck coefficient (S) were measured from room temperature to 403 K on a commercial ZEM-3 device (Ulvac-Riko, Inc. Japan). The thermal conductivity (κ) was calculated from the formula κ = ρ · D · Cp, where D is the thermal diffusivity measured by a laser flash method instrument (Netzsch LFA-457, Germany), ρ is measured based on the Archimedes method, and Cp is the heat capacity measured based on differential scanning calorimetry (Netzsch, DSC-404 F3) with a value of 0.254 J g - 1K-1, very close to the calculated value 0.253 J g - 1K-1.

[0084] The TE generator was made by connecting the Ag2Se@PI aerogel network in series using copper wires and silver paste. The size of the aerogel legs was about 1 x 3 x 15 mm3. The output performance of the TE generator at a temperature difference (ΔΤ) of 0 to 60 K was measured by a self-made device connecting two multimeters (2400 and 2182; Keithley).

[0085] Results analysis:

[0086] 1) Figure 1 The structure schematic and corresponding TEM images of the Ag2Se@PI aerogel prepared in Example 1 and the Ag2Se nanowire aerogel without PI coating layer are shown.

[0087] As can be seen from the figure, the PI coating layer uniformly coats the Ag2Se nanowire network. Due to the excellent tensile strength of more than 400 MPa and the anisotropic thermal expansion coefficient of the PI coating layer, the material has better flexibility, while retaining the high thermoelectric performance of the Ag2Se nanowire aerogel, thereby forming a solid and deformable network structure.

[0088] 2) Figure 2 The SEM morphology images of the Ag nanowire aerogel (Ag-NW aerogel), the Ag@PI aerogel prepared in Example 4, the Ag2Se nanowire aerogel (Ag2Se-NW aerogel), and the Ag2Se@PI aerogels prepared in Examples 1-3 are shown in a-f, respectively. Among them, Ag@PI-1, Ag2Se@PI-1, Ag2Se@PI-2, and Ag2Se@PI-3 represent Ag / Ag2Se aerogels coated with PI coating layers of different thicknesses.

[0089] SEM images show that the PI coating layer helps to prevent crack propagation and achieve reversible deformation. This makes the aerogel coated with the PI coating layer more robust, more elastic and more robust than the aerogel without the PI coating layer.

[0090] 3) Figure 3 The figure shows the test results of the thermoelectric performance parameters of the Ag2Se nanowire aerogel and the Ag2Se@PI aerogel prepared in Example 1.

[0091] As can be seen from the figure, the PI coating layer slightly reduces the electrical conductivity (σ) of the material, increases the Seebeck coefficient (S), and the thermal conductivity (κ) is almost unchanged. Therefore, the overall change of zT can be ignored. It is worth noting that the maximum relative deviation in all measured thermoelectric parameters is only about 3.6%, and it can be seen that the PI coating layer significantly enhances the mechanical robustness without compromising the thermoelectric performance of the Ag2Se aerogel.

[0092] 4) Figure 4 and Figure 5 The figure shows the results of the mechanical performance test of the Ag2Se@PI aerogel prepared in Example 1, and it can be seen from the figure that the bending performance of the Ag2Se@PI aerogel under a bending radius of 5mm, the resistance change range is less than 2.1% in 100 cycles, indicating that the aerogel after PI coating exhibits good bending stability, which is attributed to the stress redistribution of the porous skeleton and the mechanical performance enhancement effect of the flexible PI coating layer.

[0093] 5) Figure 6 The figure shows the stress-strain (20% to 70%) test results of the Ag2Se@PI aerogel prepared in Example 1 under different compression ratios, and it can be seen from the figure that after unloading, the stress-strain curve shows that the aerogel shows nearly complete shape recovery, and its simulated compression modulus is about 0.9kPa.

[0094] 6) Figure 7The results obtained by cyclic testing under 40% strain condition of the Ag2Se@PI aerogel prepared in Example 1 are shown, and it can be seen from the figure that the cyclic compression test under 40% strain is significantly mechanically elastic at about 0.48 kPa, and the stress retention rate is 96.5%. This performance exceeds the traditional brittle aerogel, because the PI coating layer inhibits crack propagation through interfacial energy dissipation. The corresponding resistance shows an initial decay of 12% at the beginning of the cycle, and then maintains a change of <3% in 1000 cycles, which is due to the strain-induced microstructure homogenization and effective crack inhibition of the PI coating layer. The near-perfect shape recovery and ultra-low hysteresis curve surface conforming meet the flexible electronic requirements of shape-integrated surface conforming. Importantly, this mechanical robustness is achieved without compromising the thermoelectric performance, because the interfacial covalent bonding minimizes the conductivity loss caused by delamination during deformation. These indicators collectively verify the applicability of the aerogel material to flexible electronic devices operating under dynamic mechanical and thermal loads.

[0095] 7) Figure 8 The stress-strain curves of the Ag2Se@PI aerogels prepared in Examples 1-3, as well as Ag nanowire aerogel, Ag2Se nanowire aerogel under 40% strain are shown.

[0096] As can be seen from the figure, the compression modulus of the Ag2Se nanowire aerogel is about 0.14 kPa, the compression modulus of the Ag2Se@PI-1 aerogel is about 0.30 kPa, the compression modulus of the Ag2Se@PI-2 aerogel is about 0.60 kPa, and the compression modulus of the Ag2Se@PI-3 aerogel is about 1.4 kPa. The compression modulus of the Ag2Se@PI-3 aerogel is about 10 times higher than that of the Ag2Se nanowire aerogel, so the PI coating layer can significantly improve the compression modulus of the aerogel, and increasing the thickness of the PI coating layer can improve the compression modulus of the aerogel. In addition, the Ag2Se@PI aerogel shows near-perfect shape recovery after unloading.

[0097] 8) The detection results of the Ag2Se@PI aerogels prepared in Example 1 and Example 5 and the Ag2Se@PA aerogel in terms of thermoelectric performance, and the results are shown in the table. Example 1 and Example 5 have similar performance, indicating that PI coating and PA coating have no obvious effect on the performance of the material.

[0098] Example Electrical conductivity (S / cm) Seebeck coefficient (pV / K) Power factor (μW / mK 2 )]]> Example 1 6.8 -121 10.1 Example 5 6.5 -120 9.4

[0099] The above application of specific examples to illustrate the present application is only used to help understand the present application and does not limit the present application. For those skilled in the art to which the present application belongs, according to the idea of the present application, a number of simple deductions, deformations or substitutions can be made.

Claims

1. An aerogel material with enhanced mechanical properties, characterized in that, It includes nanowire aerogel and a polymer coating layer covering the outside of the nanowire aerogel, wherein the polymer coating layer is a nanoscale polymer coating layer.

2. The mechanically enhanced aerogel material according to claim 1, characterized in that, The polymer coating layer is any one of polyimide coating layer, polyurethane coating layer, polyvinyl alcohol coating layer and polyamide coating layer; And / or, the nanowire aerogel is Ag nanowire aerogel or Ag2Se nanowire aerogel.

3. The mechanically enhanced aerogel material according to claim 1 or 2, characterized in that, The thickness of the polymer coating layer is 2nm to 20nm; Preferably, the thickness of the polymer coating layer is 10 nm to 20 nm.

4. A method for preparing an aerogel material, characterized in that, The aerogel material is the mechanically enhanced aerogel material according to any one of claims 1 to 3, and the preparation method includes: Provide nanowire aerogels; The aerogel material is prepared by coating the outside of the nanowire aerogel with a polymer coating layer.

5. The method for preparing the aerogel material according to claim 4, characterized in that, The polymer coating layer covering the outside of the nanowire aerogel includes: The nanowire aerogel is immersed in a polymer precursor solution and cured by gradient heating to form a polymer coating layer on the outside of the nanowire aerogel.

6. The method for preparing the aerogel material according to claim 5, characterized in that, The mass ratio of the nanowire aerogel to the polymer precursor solution is 1:100, and the mass fraction of the polymer precursor solution is 3% to 30%.

7. The method for preparing the aerogel material according to claim 5, characterized in that, The polymer precursor solution is prepared by dissolving any one of PMDA-ODA, PPG-TDI, PVA, and PA-DET in a solvent; Preferably, the solvent is dimethylacetamide or dimethylformamide.

8. The method for preparing the aerogel material according to claim 7, characterized in that, The polymer precursor solution was prepared by dissolving PMDA-ODA in a solvent; The gradient temperature curing process includes: pre-curing at 70℃~90℃ for 0.5h~1.5h, and then imidizing at 150℃~250℃ for 1.5h~2.5h.

9. A thermoelectric device, characterized in that, Thermoelectric generators include those made from aerogel materials with enhanced mechanical properties as described in any one of claims 1 to 3.

10. The application of the mechanically enhanced aerogel material according to any one of claims 1 to 3 in the field of thermoelectric conversion.

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