Leak-proof liquid metal-graphene material and preparation method thereof

Abstract

The application discloses a liquid metal-graphene material capable of preventing leakage, and preparation raw materials comprise a NaOH solution, a sponge, graphene sheets and a liquid metal. The liquid metal is a gallium-indium-tin ternary alloy liquid metal, and the liquid metal is subjected to high-speed stirring in an air environment to generate a part of oxidized paste-shaped liquid metal, so that the surface tension is reduced, and the liquid metal can be well attached to the sponge. The material has a simple manufacturing method, and the obtained elastic high-thermal-conductivity porous material not only avoids leakage of the liquid metal, but also helps to increase the thermal conductivity of the overall material.

Description

TECHNICAL FIELD

[0001] The application relates to the field of H01P1 / 20, in particular to a leakage-proof liquid metal-graphene material and a preparation method thereof. BACKGROUND

[0002] As a phase change heat conduction material, liquid metal has great potential application value in the field of heat dissipation due to its ultra-low thermal resistance, but the risk of leakage also limits the application of liquid metal to a certain extent.

[0003] CN107181031A discloses a silica gel graphene liquid metal and a preparation method thereof, which comprises mixing functional graphene and silica gel, mixing liquid metal and silica gel, and mixing mixed liquid A and mixed liquid B. The prepared silica gel graphene liquid metal is convenient to use and has good harmonic reduction effect. The method prepares a heat conduction material by dispersing liquid metal in an elastic polymer. Although the material can avoid leakage of liquid metal, because the liquid metal is randomly dispersed in the silica gel, the thermal conductivity of the prepared material is still low (k<5 w / mk), and the overall thermal resistance of the material is also high (R>0.3 cm 2 k / w).

[0004] CN112358854A provides a liquid metal heat conduction paste, a preparation method and application thereof. The metal heat conduction paste comprises gallium, indium, tin, zinc and silver. The provided heat conduction paste is all-metal and is not oxidized during smelting and stirring, but the thermal resistance of the material is increased or decreased in the scheme, which greatly reduces the heat dissipation performance of the total liquid metal.

[0005] Therefore, pouring liquid metal into an elastic high-thermal-conductivity porous material is a good scheme, which not only avoids leakage of liquid metal, but also helps to increase the overall thermal conductivity of the material. SUMMARY

[0006] In view of the above problems, the application discloses a leakage-proof liquid metal-graphene material. The preparation raw materials comprise NaOH solution, sponge, graphene sheet and liquid metal.

[0007] Preferably, the mass concentration of the NaOH solution is 20-40%.

[0008] Further preferably, the mass concentration of the NaOH solution is 30%.

[0009] Preferably, the average thickness of the sponge is 1-6 mm.

[0010] Further preferably, the average thickness of the sponge is 2-4 mm.

[0011] Preferably, the graphene sheet is a nano graphene sheet.

[0012] Further preferably, the average thickness of the nanographene sheet is 2-30 nm, and the average diameter is 2-12 μm.

[0013] The nanographene sheet has an average thickness of 4-20 nm and an average diameter of 5-10 μm, and is available from Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, product number: TNGNPs.

[0014] Preferably, the liquid metal is a gallium-indium-tin ternary alloy liquid metal.

[0015] Further preferably, the melting point of the liquid metal is less than 15℃, and more preferably, the melting point of the liquid metal is 10℃.

[0016] The second aspect of the present application discloses a preparation method of the leak-proof liquid metal-graphene material, comprising the following steps:

[0017] (1) Sponge surface treatment;

[0018] (2) Preparation of graphene dispersion liquid;

[0019] (3) Sponge modification;

[0020] (4) Liquid metal filling.

[0021] As a preferred technical solution, the step (1) sponge surface treatment specifically comprises: soaking the sponge in NaOH solution for 20-40 minutes to modify the surface of the sponge.

[0022] Preferably, the sponge is soaked in NaOH solution for 30 minutes to modify the surface of the sponge.

[0023] As a preferred technical solution, the step (2) preparation of graphene dispersion liquid specifically comprises: ultrasonic preparation of a uniform graphene dispersion liquid in NaOH solution.

[0024] Preferably, the ultrasonic process lasts for 10-30 minutes, and more preferably, for 15 minutes.

[0025] Further preferably, the mass ratio of the graphene sheet to the NaOH solution is 1:(0.5-10).

[0026] As a preferred technical solution, the step (3) sponge modification specifically comprises: soaking the sponge obtained in step (1) in the graphene solution obtained in step (2) for extrusion, then drying the sponge, soaking it again in the graphene solution for extrusion, drying it again, and repeating the process multiple times.

[0027] Preferably, the repeating is performed until the volume of graphene attached to the sponge is 20-30% of the volume of the sponge.

[0028] Further preferably, the repeating is performed until the volume of graphene attached to the sponge is 25% of the volume of the sponge.

[0029] Preferably, the drying temperature is 50-70℃, more preferably 60℃.

[0030] As a preferred technical solution, the step (4) of filling the liquid metal is specifically: after stirring and oxidizing the gallium-indium-tin ternary alloy liquid metal, the gallium-indium-tin ternary alloy liquid metal is filled into the sponge with graphene attached to the surface.

[0031] Preferably, the stirring of the gallium-indium-tin ternary alloy liquid metal is specifically: the gallium-indium-tin ternary alloy liquid metal is stirred at high speed in an air environment to generate a partially oxidized paste-like liquid metal.

[0032] Further preferably, the viscosity of the paste-like liquid metal is 1500-3000 cps, and the viscosity is measured at 25℃.

[0033] The surface tension of the liquid metal is large, and it is difficult to achieve attachment in the sponge. Therefore, the gallium-indium-tin ternary alloy liquid metal is stirred at high speed in an air environment to generate a partially oxidized paste-like liquid metal, thereby reducing the surface tension and allowing good attachment to the sponge. However, the thermal conductivity and electrical conductivity of this structure still need to be further improved. During extensive research, the applicant accidentally discovered that modifying the sponge with graphene before filling the liquid metal allows graphene to attach to the sponge, especially when the volume of graphene attached to the sponge is 20-30% of the volume of the sponge, which can further improve the attachment ability. In addition, the thermal resistance of the obtained leak-proof liquid metal-graphene material is low, only 0.05 cm 2 k / w. The applicant believes that the possible reason is that the graphene attached to the sponge has excellent thermal and electrical conductivity, which further improves the overall performance of the material. At the same time, the attachment of graphene also increases the complexity of the porous structure of the sponge, reduces the porosity, and improves the friction, thereby allowing the liquid metal to be filled more firmly into the sponge, effectively preventing the leakage of the liquid metal.

[0034] Advantages

[0035] 1. By stirring the gallium-indium-tin ternary alloy liquid metal at high speed in an air environment, a partially oxidized paste-like liquid metal is generated, thereby reducing the surface tension and allowing good attachment to the sponge.

[0036] 2、The sponge is modified by graphene, especially when the volume of graphene attached to the sponge is 20-30% of the volume of the sponge, the attachment capacity can be further improved, and the thermal resistance of the obtained leak-proof liquid metal-graphene material is low, only 0.05cm 2 k / w.

[0037] 3、The material is simple to make, and the obtained elastic high-thermal-conductivity porous material not only avoids leakage of liquid metal, but also helps to increase the thermal conductivity of the overall material. DETAILED DESCRIPTION

[0038] Example 1

[0039] The embodiment 1 discloses a leak-proof liquid metal-graphene material, and the preparation raw materials are: NaOH solution, sponge, graphene sheet, and liquid metal.

[0040] The mass concentration of the NaOH solution is 30%.

[0041] The sponge is supplied by Zhongxin Sponge Operating Department (model: 20-25), and the average thickness is 2mm-4mm.

[0042] The graphene sheet is a nano graphene sheet, which is purchased from the Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, and the product number is TNGNPs, the average thickness of the nano graphene sheet is 4-20nm, and the average diameter is 5-10μm.

[0043] The liquid metal is a gallium-indium-tin ternary alloy liquid metal (gallium, indium powder and tin particles (purity: 99.99%) are purchased from Foshan Rongshun New Material Technology Co., Ltd.), and the melting point of the liquid metal is 10℃.

[0044] The embodiment 1 discloses a preparation method of the leak-proof liquid metal-graphene material, and the steps are as follows:

[0045] (1) Sponge surface treatment: the sponge is soaked in the NaOH solution for 30 minutes to modify the surface of the sponge.

[0046] (2) Preparation of graphene dispersion liquid: the graphene sheet is ultrasonically prepared in the NaOH solution to prepare a uniform graphene dispersion liquid; the ultrasonic process lasts for 15 minutes.

[0047] The mass ratio of the graphene sheet to the NaOH solution is 1:2.

[0048] (3) Sponge modification: the sponge obtained in step (1) is immersed in the graphene solution obtained in step (2) and extruded, then the sponge is dried, re-immersed in the graphene solution and extruded, dried again, and repeated several times until the volume of graphene attached to the sponge is 25% of the volume of the sponge.

[0049] The drying temperature is 60°C.

[0050] (4) Liquid metal infusion: gallium-indium-tin ternary alloy liquid metal is stirred at high speed in air environment to generate partially oxidized paste-shaped liquid metal, which is infused into the sponge with graphene attached to the surface.

[0051] The viscosity of the paste-shaped liquid metal is 2000 cps, which is measured at 25°C.

[0052] Example 2

[0053] The difference between this embodiment and embodiment 1 is that step (3) sponge modification: the sponge obtained in step (1) is immersed in the graphene solution obtained in step (2) and extruded, then the sponge is dried, re-immersed in the graphene solution and extruded, dried again, and repeated several times until the volume of graphene attached to the sponge is 10% of the volume of the sponge.

[0054] Example 3

[0055] The difference between this embodiment and embodiment 1 is that step (3) sponge modification: the sponge obtained in step (1) is immersed in the graphene solution obtained in step (2) and extruded, then the sponge is dried, re-immersed in the graphene solution and extruded, dried again, and repeated several times until the volume of graphene attached to the sponge is 40% of the volume of the sponge.

[0056] Example 4

[0057] The difference between this embodiment and embodiment 1 is that the viscosity of the paste-shaped liquid metal is 4000 cps, which is measured at 25°C.

[0058] Performance tests

[0059] Thermal resistance test: test the interfacial thermal resistance at 20 psi according to ASTM D5470

[0060] Thermal resistance cm 2 k / w <!-- 3 -->]]> Example 1 0.05 Example 2 0.08 Example 3 0.06 Example 4 0.07

Claims

1. A leak-proof liquid metal-graphene material, characterized in that, The raw materials for preparation include: NaOH solution, sponge, graphene sheet, and liquid metal; The mass concentration of the NaOH solution is 20-40%; The graphene sheet is a nano-graphene sheet; The average thickness of the nanographene sheets is 2-30 nm, and the average diameter is 2-12 μm; The volume of graphene attached to the sponge is 20-30% of the sponge's volume.

2. The liquid metal-graphene material according to claim 1, characterized in that, The average thickness of the sponge is 1mm-6mm.

3. The liquid metal-graphene material according to claim 1, characterized in that, The liquid metal is a gallium indium tin ternary alloy liquid metal.

4. The liquid metal-graphene material according to claim 3, characterized in that, The melting point of the liquid metal is less than 15°C.

5. A method for preparing a liquid metal-graphene material according to any one of claims 1-4, characterized in that, Includes the following steps: (1) Sponge surface treatment; (2) Preparation of graphene dispersion; (3) Sponge finishing; (4) Liquid metal is poured in.

6. The method for preparing liquid metal-graphene material according to claim 5, characterized in that, The specific steps of step (1) sponge surface treatment are as follows: soak the sponge in NaOH solution for 20-40 minutes to modify the sponge surface.

7. The method for preparing liquid metal-graphene material according to claim 6, characterized in that, The specific preparation of the graphene dispersion in step (2) involves ultrasonically preparing a uniform graphene dispersion by ultrasonically dissolving graphene sheets in NaOH solution.