CN116063731B

CN116063731B - High-heat-conductivity silica gel material, preparation method and application

Info

Publication number: CN116063731B
Application number: CN202310129644.XA
Authority: CN
Inventors: 陈涛; 谷金翠; 肖鹏
Original assignee: Ningbo Institute of Material Technology and Engineering of CAS
Current assignee: Ningbo Institute of Material Technology and Engineering of CAS
Priority date: 2023-02-17
Filing date: 2023-02-17
Publication date: 2023-08-01
Anticipated expiration: 2043-02-17
Also published as: CN116063731A

Abstract

The invention discloses a high-heat-conductivity silica gel material, a preparation method and application thereof, belonging to the technical field of silica gel materials, and comprising the following steps: (1) Preparing a mixed solution A by taking a prepolymerization solution, a curing agent and a foaming agent as raw materials; (2) Dispersing MXene and polypyrrole nano rods into ethanol, stirring for reaction, centrifuging, drying, and dispersing with water again to obtain MXene/polypyrrole aqueous dispersion serving as a mixed solution B; (3) And mixing the mixed solution B and the mixed solution A, removing bubbles, transferring to a mold, performing hot press molding to obtain a foaming silica gel material, and further performing freeze drying to obtain the high-heat-conductivity silica gel material. The silica gel material prepared by the method has excellent mechanical property and heat conduction capability due to the synergistic promotion effect of the MXene and polypyrrole composite system, and the problems of agglomeration and rapid reduction of mechanical property caused by adding a large amount of heat conduction filler in the traditional silica gel material are solved.

Description

High-heat-conductivity silica gel material, preparation method and application

Technical Field

The invention belongs to the technical field of silica gel materials, and particularly relates to a high-heat-conductivity silica gel material, a preparation method and application thereof.

Background

In recent years, the global new energy automobile industry is developed to drive into a fast traffic lane, and new energy automobile markets are vigorously developed, so that in order to meet the supply requirement of the new energy automobile and improve the service performance of the new energy automobile, the safety, stability, service life, cruising ability and the like of a power battery system of the new energy automobile are required to be studied more intensively.

The heat-conducting silica gel is used as a heat-conducting filling material with excellent heat conduction, insulation and compression resistance, is a main stream for transferring heat between a heating part and a heat dissipation part in the prior art, and is required to solve the problem of high temperature generated by a power battery system for a new energy automobile. Along with the increasing importance of new energy automobile manufacturers to the safety of power battery systems, therefore, also put forward higher requirements on heat conduction silica gel heat dissipation materials, not only are the excellent heat dissipation effects required, but also the multifunctional heat dissipation materials are required to have excellent mechanical properties while achieving the heat dissipation effects.

The heat conducting silica gel sheet is a heat conducting medium synthesized by taking silica gel as a matrix, adding filler and adopting a special processing technology. The heat-conducting silica gel sheet can fill gaps and accelerate heat transfer between the heating part and the heat dissipation part, reduce contact thermal resistance generated between the heat source surface and the contact surface of the heat dissipation device, and avoid heat accumulation in the electronic equipment. The most studied at present is to use carbon materials, silicon nitride, liquid metal, etc. as the heat conductive filler.

In the prior art, chinese patent document with publication number of CN115340767A discloses a high heat conduction insulating silica gel and a preparation method thereof, wherein a high heat conduction fluorinated graphene film is adopted as a heat conduction filler to improve heat conduction capacity, and the heat conductivity in the vertical direction of the thickness of the high heat conduction fluorinated graphene film is 10W/mK-18W/mK; chinese patent publication No. CN111218115a discloses a high thermal conductivity silicone sheet prepared by using a carbon nanotube high thermal conductivity filler with a high aspect ratio. When the carbon material is used as the heat conducting filler, although the carbon material plays a certain role in silica gel filling, the dispersion addition amount is limited, the heat conducting performance is limited, the carbon material has conductivity and is easy to cause short circuit and the like in a state of being separated from an adhesive matrix or gathered, in addition, the compatibility of the carbon material and the adhesive matrix is poor, the compatibility and the dispersion effect of an interface can be improved only by carrying out surface treatment on the carbon material, most of the carbon material has anisotropy, the conduction efficiency can be influenced by the distribution direction of particles, and the conduction of heat channels in certain directions in a heat conducting network is not smooth.

Chinese patent publication No. CN111662550a discloses a thermally conductive silica gel composition comprising a thermally conductive filler, the thermally conductive filler comprising a thermally conductive agent and a coupling agent coated on the surface of the thermally conductive agent, the thermally conductive agent comprising a first thermally conductive agent and a second thermally conductive agent, the first thermally conductive agent being inorganic metal compound particles (aluminum oxide, aluminum nitride, aluminum hydroxide, magnesium oxide, beryllium oxide, zinc oxide, etc.), the second thermally conductive agent being one or more of silicon oxide, silicon carbide, silicon nitride, boron oxide, boron carbide, boron nitride; the thermal conductivity of the thermal conductive silica gel is improved by filling a larger amount of thermal conductive filler, and the thermal conductivity is generally higher as the thermal conductive filler is filled more and the particle diameter of the thermal conductive filler is smaller. However, the tensile property of the heat-conducting silica gel can be greatly reduced due to excessive addition of the heat-conducting filler, so that the breakage phenomenon of the heat-conducting silica gel occurs in the use process, the performance stability of the heat-conducting silica gel sheet is seriously affected, and the practical application of the heat-conducting silica gel material is restricted.

Chinese patent publication No. CN107488436a discloses a two-component heat conductive silicone sheet containing a liquid metal heat conductive filler, which uses a low melting point metal or alloy including indium, gallium, and alloys thereof with other metals (e.g., indium gallium alloy, gallium tin zinc alloy, indium gallium tin alloy, indium gallium bismuth tin alloy, indium bismuth tin silver alloy, etc.) as a main heat conductive portion of the heat conductive silicone sheet. In general, since van der Waals force between liquid metals is very large, droplet particles dispersed in a polymer matrix are large, and uniformity of size is poor, and in addition, bonding property between metal droplets and the polymer matrix is poor, and interface difference enables heat conduction performance of the whole heat conduction material not to be improved and reduced.

Therefore, how to obtain a silica gel material with excellent mechanical properties and heat conducting properties is still a technical problem to be solved.

Disclosure of Invention

The invention provides a preparation method of a high-heat-conductivity silica gel material, which has simple and efficient process, and the prepared silica gel material has excellent mechanical property and heat-conductivity, tensile strength of not lower than 3.2Mpa, elongation at break of not lower than 182%, and room temperature heat conductivity of not lower than 6.7W/m.k, and has wide application prospects in the fields of heat dissipation of new energy automobile power battery systems, heat dissipation of electronic components and the like.

The technical scheme adopted is as follows:

a preparation method of a high-heat-conductivity silica gel material comprises the following steps:

(1) Preparing a mixed solution A by taking a prepolymerization solution, a curing agent and a foaming agent as raw materials;

(2) Dispersing MXene and polypyrrole nano rods into ethanol, stirring for reaction, centrifuging, drying, and dispersing with water again to obtain MXene/polypyrrole aqueous dispersion serving as a mixed solution B;

(3) And mixing the mixed solution B and the mixed solution A, removing bubbles, transferring to a mold, performing hot press molding to obtain a foaming silica gel material, and further performing freeze drying to obtain the high-heat-conductivity silica gel material.

According to the invention, by introducing the MXene and the polypyrrole nanorods into the silica gel material system, due to the synergistic effect of the MXene and the polypyrrole composite system, the silica gel material prepared by the method has excellent mechanical property and heat conduction capability, on one hand, the interaction between polypyrrole molecular chains is enhanced by adding the MXene, and the mechanical property and the heat conductivity of the silica gel material are improved; on the other hand, polypyrrole molecules are beneficial to interface connection between MXene sheets and are beneficial to uniform dispersion of MXene in a silica gel matrix; the method solves the problems of agglomeration and rapid reduction of mechanical properties caused by adding a large amount of heat conducting fillers in the traditional silica gel material, reduces interface thermal resistance and improves the heat conducting capacity of the silica gel material.

The pre-polymerized liquid is at least one of Polydimethylsiloxane (PDMS) or aliphatic aromatic random copolyester (Ecoflex); the curing agent is a platinum catalyst; the foaming agent is thermoplastic expandable hollow polymer microsphere with the diameter of 10-40 mu m, and the component is at least one of polymalonic acid or polyacetoacetic acid.

Preferably, in the mixed solution A, the mass ratio of the prepolymerization solution, the curing agent and the foaming agent is 1:0.1:0.01-0.05.

Preferably, the mass ratio of the MXene to the polypyrrole nanorods is 1:1-4, the reaction temperature is 40-80 ℃ and the reaction time is 0.5-3h.

Preferably, the MXene is of a single-layer or double-layer structure, preferably of a single-layer structure, the sheet size is 4-10 mu m, and the content of hydroxyl functional groups is 2% -10%; the diameter of the polypyrrole nano rod is 70-90nm, and the content of amino functional groups is 2% -8%.

In the MXene/polypyrrole aqueous dispersion, the concentration of the MXene/polypyrrole is 0.5-2mg/mL.

Preferably, in the step (3), the parameters of the hot press molding are: the temperature is 160-200deg.C, the pressure is 1-4Mpa, and the time is 4-10min.

Preferably, in step (3), the freeze-drying parameters are: the temperature is-190- -40 ℃ and the time is 0.5-2h.

The invention also provides the high-heat-conductivity silica gel material prepared by the preparation method of the high-heat-conductivity silica gel material. The content of the conductive filler in the high-heat-conductivity silica gel material is about 0.02-0.09%, and the high-heat-conductivity silica gel material has excellent properties of tensile strength not lower than 3.2Mpa, elongation at break not lower than 182% and room temperature heat conductivity not lower than 6.7W/m.k on the basis of the content of the ultralow conductive filler.

The invention also provides application of the high-heat-conductivity silica gel material in the heat dissipation field, and the silica gel material has wide application prospects in the heat dissipation field of new energy automobile power battery systems and the heat dissipation field of electronic components.

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

(1) In the high-heat-conductivity silica gel material prepared by the method, the addition of the MXene enhances the interaction among polypyrrole molecular chains, improves the mechanical property and the heat conductivity of the silica gel material, and the polypyrrole molecules are favorable for the interface connection among MXene sheets, so that the MXene is easy to uniformly disperse in a silica gel matrix, the problems of agglomeration and rapid reduction of the mechanical property caused by adding a large amount of heat-conducting filler in the traditional silica gel material are solved, the interface thermal resistance is reduced, and the heat conduction capacity of the silica gel material is improved.

(2) The invention provides a high-heat-conductivity silica gel material, which consists of a prepolymerization solution, a curing agent, a foaming agent, MXene and a polypyrrole nanorod, wherein the synergistic effect of a MXene and polypyrrole composite system endows the silica gel material with excellent mechanical property and high heat-conductivity, the tensile strength of the silica gel material is not lower than 3.2Mpa, the elongation at break is not lower than 182%, the room-temperature heat conductivity is not lower than 7.6W/m.k, and the comprehensive performance of the silica gel material is superior to that of most of reported heat-conductivity silica gel materials.

(3) The high-heat-conductivity silica gel material is prepared by combining a hot pressing method and a freeze drying method, the process is simple and controllable, the implementation is easy, the mass production is easy, and compared with the traditional hot pressing normal-temperature cooling method, the method can rapidly fix the pore diameter structure, avoid the collapse of the pore structure in the cooling process, and endow the silica gel material with stable mechanical property.

Drawings

Fig. 1 is a schematic structural diagram of the high thermal conductivity silica gel material.

Fig. 2 is a morphology diagram of the high thermal conductivity silica gel material prepared in example 1.

FIG. 3 is a topography of an MXene and polypyrrole nanorod in example 1, where A is MXene and B is polypyrrole nanorod.

Detailed Description

The invention is further elucidated below in connection with the examples and the accompanying drawing. It is to be understood that these examples are for illustration of the invention only and are not intended to limit the scope of the invention.

In the examples and comparative examples, the pre-polymer solution and platinum catalyst used were purchased from Yitai, hangzhou, and the expandable hollow polymeric microspheres were purchased from Nanjiepu polymeric materials, MXene was purchased from Fisher biotechnology, zhengzhou, and the polypyrrole nanorod reference Coral-like hierarchically nanostructured membrane with high free volume for salt-free polar-enabled water purification, materials Today Physics,25 (2022) 100715.

Example 1

(1) Uniformly mixing 10g of polydimethylsiloxane, 1g of platinum catalyst and 0.5g of polymalonic acid hollow polymer microsphere with the diameter of about 10 mu m, and fully and uniformly stirring to obtain a mixed solution A, wherein the total mass of the mixed solution A is 11.5g;

(2) Uniformly dispersing 0.1g of MXene (single layer, sheet size is about 4 mu m, the hydroxyl content is 2%) and 0.1g of polypyrrole nanorod (diameter is 70nm, the amino content is 2%) into 100mL of ethanol solution, stirring and reacting for 1h at 40 ℃, centrifuging to remove unreacted impurities, drying and dispersing again with water to obtain MXene/polypyrrole aqueous dispersion with the concentration of 1.0mg/mL, and taking the MXene/polypyrrole aqueous dispersion as a mixed solution B;

(3) Adding 5mL of the mixed solution B obtained in the step (2) into the mixed solution A under the magnetic stirring of 300r/min, then placing the mixed solution B in a vacuum dryer for defoaming for 2 hours, uniformly dispersing the mixed solution B, transferring the mixed solution B into a silica gel mold, and controlling the hot-press molding temperature to 160 ℃ and the pressure to 1Mpa and the time to 10 minutes to obtain a foamed silica gel material;

(4) And (3) rapidly putting the foamed silica gel material obtained in the step (3) into a freeze dryer, and controlling the freeze drying temperature to be minus 40 ℃ for 2 hours to obtain the high-heat-conductivity silica gel material.

Characterization of results: the structural schematic diagram and the morphology diagram of the high thermal conductivity silica gel material prepared in the embodiment 1 are shown in fig. 1 and fig. 2 respectively, and the morphology diagrams of the used MXene and polypyrrole nanorods are shown in A and B in fig. 3 respectively; measuring the tensile property and the elongation at break of the silica gel material by using an ASTM D412 method, and measuring the heat conductivity coefficient of the silica gel material by using an ASTM D5470 method; the results show that the tensile property of the silica gel material prepared in the embodiment is 3.2MPa, the elongation at break is 182% and the thermal conductivity is 6.9W/m.k.

Example 2

(1) Uniformly mixing 16g of polydimethylsiloxane, 1.6g of platinum catalyst and 0.8g of polymalonic acid hollow polymer microsphere with the diameter of about 10 mu m, and fully and uniformly stirring to obtain a mixed solution A, wherein the total mass of the mixed solution A is 18.4g;

(2) Uniformly dispersing 0.16g of MXene (single layer, sheet size is about 4 mu m, the hydroxyl content is 2%) and 0.16g of polypyrrole nanorod (diameter is 70nm, the amino content is 2%) into 100mL of ethanol solution, stirring and reacting for 1h at 40 ℃, centrifuging to remove unreacted impurities, drying and dispersing again with water to obtain MXene/polypyrrole aqueous dispersion with the concentration of 1mg/mL, and taking the MXene/polypyrrole aqueous dispersion as a mixed solution B;

(3) Adding 5mL of the mixed solution B obtained in the step (2) into the mixed solution A under the magnetic stirring of 300r/min, then placing the mixed solution B in a vacuum dryer for defoaming for 2 hours, uniformly dispersing, transferring the mixed solution B into a silica gel mold, and controlling the hot-press molding temperature to 160 ℃ and the pressure to 1Mpa and the time to 10 minutes to obtain the foamed silica gel material.

Characterization of results: the tensile properties and elongation at break of the resulting silicone materials were measured by the ASTM D412 method, and the thermal conductivity of the resulting silicone materials was measured by the ASTM D5470 method. The results show that the tensile property of the silica gel material prepared in the embodiment is 3.4MPa, the elongation at break is 188%, and the thermal conductivity is 6.7W/m.k. Compared with the embodiment 1, the embodiment increases the total mass of the mixed solution A, improves the mechanical property and slightly reduces the heat conductivity coefficient.

Example 3

(2) Uniformly dispersing 0.2g of MXene (single layer, sheet size is about 4 mu m, the hydroxyl content is 2%) and 0.2g of polypyrrole nanorod (diameter is 70nm, the amino content is 2%) into 100mL of ethanol solution, stirring and reacting for 1h at 40 ℃, centrifuging to remove unreacted impurities, drying and dispersing again with water to obtain an MXene/polypyrrole aqueous dispersion with the concentration of 2mg/mL, and taking the MXene/polypyrrole aqueous dispersion as a mixed solution B;

Characterization of results: measuring the tensile property and the elongation at break of the obtained silica gel material by using an ASTM D412 method, and measuring the heat conductivity coefficient of the obtained silica gel material by using an ASTM D5470 method; the results show that the tensile property of the silica gel material prepared in the embodiment is 3.3MPa, the elongation at break is 198%, and the thermal conductivity is 7.2W/m.k. In this example, the amount of MXene and polypyrrole was increased compared to example 1, and both mechanical and thermal conductivity were improved.

Example 4

The preparation method of the high thermal conductivity silica gel material in this example is different from that of example 3 only in that a 2mg/mL aqueous dispersion of MXene/polypyrrole prepared from 0.2g of MXene and 0.8g of polypyrrole nanorod is used as the mixed solution B.

Characterization of results: the tensile properties and elongation at break of the resulting silicone materials were measured by the ASTM D412 method, and the thermal conductivity of the resulting silicone materials was measured by the ASTM D5470 method. The results show that the tensile property of the silica gel material prepared in the embodiment is 3.6Mpa, the elongation at break is 205% and the thermal conductivity is 7.8W/m.k.

Example 5

The preparation method of the high thermal conductivity silica gel material in this example is different from that of example 3 only in that the sheet size of MXene is about 10 μm and the diameter of polypyrrole nanorods is 90nm.

Characterization of results: the tensile properties and elongation at break of the resulting silicone materials were measured by the ASTM D412 method, and the thermal conductivity of the resulting silicone materials was measured by the ASTM D5470 method. The results show that the tensile property of the silica gel material prepared in the embodiment is 3.5MPa, the elongation at break is 199%, and the thermal conductivity is 7.3W/m.k.

Example 6

The preparation method of the high thermal conductivity silica gel material in this example is different from that of example 3 only in that the hydroxyl content of MXene is 10% and the amino content of polypyrrole nanorod is 8%.

Characterization of results: the tensile properties and elongation at break of the resulting silicone materials were measured by the ASTM D412 method, and the thermal conductivity of the resulting silicone materials was measured by the ASTM D5470 method. The results show that the tensile property of the silica gel material prepared in the embodiment is 3.6MPa, the elongation at break is 201%, and the thermal conductivity is 7.4W/m.k.

Example 7

The preparation method of the high thermal conductivity silica gel material in this example is different from that in example 3 only in that the hot pressing temperature is 200 ℃.

Characterization of results: the tensile properties and elongation at break of the resulting silicone materials were measured by the ASTM D412 method, and the thermal conductivity of the resulting silicone materials was measured by the ASTM D5470 method. The results show that the tensile property of the silica gel material prepared in the embodiment is 3.4MPa, the elongation at break is 199%, and the thermal conductivity is 7.3W/m.k. This example shows an increase in hot pressing temperature and an increase in mechanical and thermal conductivity as compared with example 3.

Example 8

The preparation method of the high thermal conductivity silica gel material in this example is different from that in example 3 only in that the hot pressing pressure is 4Mpa.

Characterization of results: the tensile properties and elongation at break of the resulting silicone materials were measured by the ASTM D412 method, and the thermal conductivity of the resulting silicone materials was measured by the ASTM D5470 method. The results show that the tensile property of the silica gel material prepared in the example is 3.5MPa, the elongation at break is 207%, and the thermal conductivity is 7.4W/m.k. This example has an increased hot pressing pressure and an increased mechanical and thermal conductivity compared to example 3.

Example 9

Compared with the embodiment 3, the preparation method of the high heat conduction silica gel material in the embodiment is only different in that Ecoflex is selected as the pre-polymerization liquid.

Characterization of results: the tensile properties and elongation at break of the resulting silicone materials were measured by the ASTM D412 method, and the thermal conductivity of the resulting silicone materials was measured by the ASTM D5470 method. The results show that the tensile property of the silica gel material prepared in the example is 3.4MPa, the elongation at break is 187%, and the thermal conductivity is 6.8W/m.k.

Example 10

Compared with the embodiment 9, the preparation method of the high heat conduction silica gel material is only different in that the foaming agent is a polyacetoacetic acid hollow polymer microsphere.

Characterization of results: the tensile properties and elongation at break of the resulting silicone materials were measured by the ASTM D412 method, and the thermal conductivity of the resulting silicone materials was measured by the ASTM D5470 method. The results show that the tensile property of the silica gel material prepared in the embodiment is 3.3MPa, the elongation at break is 188%, and the thermal conductivity is 6.9W/m.k.

Example 11

The preparation method of the high thermal conductivity silica gel material in this example is different from that in example 10 only in that the diameter of the foaming agent is about 40. Mu.m.

Characterization of results: the tensile properties and elongation at break of the resulting silicone materials were measured by the ASTM D412 method, and the thermal conductivity of the resulting silicone materials was measured by the ASTM D5470 method. The results show that the tensile property of the silica gel material prepared in the embodiment is 3.5MPa, the elongation at break is 183%, and the thermal conductivity is 6.8W/m.k.

Comparative example 1

The preparation method of the silica gel material in this comparative example is different from that of example 3 only in that the freeze-drying process of step (4) is not performed.

Characterization of results: the tensile properties and elongation at break of the resulting silicone materials were measured by the ASTM D412 method, and the thermal conductivity of the resulting silicone materials was measured by the ASTM D5470 method. The results show that the tensile property of the silica gel material prepared in the comparative example is 2.1MPa, the elongation at break is 142%, and the thermal conductivity is 6.2W/m.k.

Comparative example 2

The preparation method of the silica gel material in this comparative example is different from that of example 3 only in that the freeze-drying temperature is-240 ℃.

Characterization of results: the tensile properties and elongation at break of the resulting silicone materials were measured by the ASTM D412 method, and the thermal conductivity of the resulting silicone materials was measured by the ASTM D5470 method. The result shows that the tensile property of the silica gel material prepared by the comparative example is 2.1MPa, the elongation at break is 160%, the heat conductivity coefficient is 4.9W/m.k, and the material rapidly collapses due to the too low freeze-drying temperature, so that the mechanical property and the heat conductivity of the silica gel material are affected.

Comparative example 3

The silica gel material of this comparative example was prepared by a method differing from example 3 only in that a 1mg/mL aqueous MXene/polypyrrole dispersion prepared from 0.4g of MXene and 2.0g of polypyrrole nanorods was used as the mixed solution B.

Characterization of results: the tensile properties and elongation at break of the resulting silicone materials were measured by the ASTM D412 method, and the thermal conductivity of the resulting silicone materials was measured by the ASTM D5470 method. The result shows that the excessive proportion of the polypyrrole nanorods to the MXene causes agglomeration of part of the MXene and the polypyrrole nanorods, so that the tensile property of the silica gel material prepared by the comparative example is 1.9MPa, the elongation at break is 127%, and the heat conductivity coefficient is 5.7W/m.k.

In summary, the invention provides a preparation method of a silica gel material with excellent mechanical properties and high heat conduction performance. The silica gel material system is prepared by combining a prepolymerization liquid, a curing agent, a foaming agent, MXene and polypyrrole nanorods through a hot pressing method and a freeze drying method. Because of the synergistic effect of the MXene and the polypyrrole composite system, the tensile strength of the silica gel material system is not lower than 3.2Mpa, the elongation at break is not lower than 182%, the room temperature thermal conductivity is not lower than 6.7W/m.k, and the excellent comprehensive capacity of the silica gel material is far higher than that of the silica gel material used at present, so that the silica gel material has wide application prospect in the fields of heat dissipation of new energy automobile power battery systems, heat dissipation of electronic components and the like.

While the foregoing embodiments have been described in detail in connection with the embodiments of the invention, it should be understood that the foregoing embodiments are merely illustrative of the invention and are not intended to limit the invention, and any modifications, additions, substitutions and the like made within the principles of the invention are intended to be included within the scope of the invention.

Claims

1. The preparation method of the high-heat-conductivity silica gel material is characterized by comprising the following steps of:

(1) Preparing a mixed solution A by taking a prepolymerization solution, a curing agent and a foaming agent as raw materials, wherein the prepolymerization solution is polydimethylsiloxane;

(3) Mixing the mixed solution B and the mixed solution A, removing bubbles, transferring to a mold, performing hot press molding to obtain a foaming silica gel material, and further performing freeze drying to obtain the high-heat-conductivity silica gel material;

the mass ratio of MXene to polypyrrole nanorods is 1:1-4.

2. The method for preparing the high thermal conductivity silica gel material according to claim 1, wherein the curing agent is a platinum catalyst; the foaming agent is thermoplastic expandable hollow polymer microsphere with the diameter of 10-40 mu m.

3. The preparation method of the high thermal conductivity silica gel material according to claim 1 or 2, wherein in the mixed solution A, the mass ratio of the prepolymerization solution, the curing agent and the foaming agent is 1:0.1:0.01-0.05.

4. The method for preparing a high thermal conductivity silica gel material according to claim 1, wherein the reaction temperature is 40-80 ℃ and the reaction time is 0.5-3 hours; in the MXene/polypyrrole aqueous dispersion, the concentration of the MXene/polypyrrole is 0.5-2mg/mL.

5. The method for preparing a high thermal conductivity silica gel material according to claim 1, wherein MXene is a single layer or a double layer structure, and the content of hydroxyl functional groups is 2% -10%.

6. The method for preparing a high thermal conductivity silica gel material according to claim 1, wherein the amino functional group content of the polypyrrole nanorods is 2% -8%.

7. The method for preparing a high thermal conductivity silica gel material according to claim 1, wherein the parameters of the hot press molding are as follows: the temperature is 160-200deg.C, the pressure is 1-4Mpa, and the time is 4-10min.

8. The method for preparing a high thermal conductivity silica gel material according to claim 1, wherein the freeze-drying parameters are: the temperature is-190-40 ℃ and the time is 0.5-2h.

9. The high thermal conductive silica gel material according to any one of claims 1 to 8.

10. The use of the high thermal conductivity silicone material according to claim 9 in the field of heat dissipation.