Graphene micro-nano cavity heat conduction film, use thereof, and graphene micro-nano cavity phase change vapor chamber

Abstract

The present invention aims to provide a graphene micro-nano cavity heat conduction film that allows the thickness thereof to ranging from 0.15 mm to 3 mm, achieving better thermal and electrical conductivity and causing rebound stress at 80% ≥ 0.05 MPa. The graphene micro-nano cavity heat conduction film prepared via the present invention has an areal density of 0.002 g / cm2 to 0.2 g / cm2, which ensures its applicability in pressure sensors, supercapacitors, fuel cells, carbon catalytic materials, switches, and optical modules. The graphene micro-nano cavity heat conduction film obtained via the present invention is made up of pure graphite, has a fluffy and porous microstructure, and has uniform and stable properties; additionally, during subsequent use, said film can be combined with other materials, has a wide application range, significant potential, and can be used in a variety of fields of application. The present invention is a material with high thermal and electrical conductivity, which is rare in the current market.

Description

Graphene micro-nano cavity thermal conductive film and its applications and graphene micro-nano cavity phase change temperature plate Technical Field

[0001] The present invention belongs to the field of graphene technology, and in particular relates to a graphene micro-nano cavity thermal conductive film and applications thereof, and a graphene micro-nano cavity phase change temperature equalizing plate. Background Art

[0002] Graphene micro-nano cavity thermal conductive film is a thermal conductive and heat dissipation product that uses graphene as raw material only. There are currently many graphene thermal conductive films on the market, hoping to use the modification of graphene materials to obtain products with good thermal conductivity for heat dissipation of electronic equipment.

[0003] Chinese invention patent CN116691084A discloses a graphene thermally conductive film. The patent describes a thermally conductive product with high thermal conductivity and suitable thickness, achieved by modifying graphene, epoxy resin, glass fiber, and a silane coupling agent. However, the inclusion of glass fiber and organic materials in the patent not only obscures the inherent properties of the graphene, but also the use of adhesives in the thermally conductive film, resulting in poor weather resistance over long periods of use, limiting its application range. Furthermore, the use of adhesives increases process requirements, and the increased thickness reduces the effectiveness of graphene's properties, significantly limiting its use in products requiring high thermal conductivity.

[0004] Therefore, in view of the current application of graphene materials in thermal conductivity and heat dissipation scenarios, it is an important challenge to develop a product that uses graphene as raw material and retains the original properties of graphene. Technical Solutions

[0005] The purpose of the present invention is to provide a graphene micro-nano cavity thermal conductive film with a thickness of 0.15-3 mm, achieving good thermal and electrical conductivity, and making 80% of the rebound stress ≥ 0.01 MPa.

[0006] In order to achieve the above-mentioned object, the first aspect of the present invention provides a graphene micro-nano cavity thermal conductive film, which is obtained by coating graphene oxide into a film, foaming, carbonizing, and graphitizing;

[0007] In some preferred embodiments, the thickness of the thermally conductive film is 0.15~3 mm, and the thickness can be 0.15 mm, 0.18 mm, 0.2 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.63 mm, 0.65 mm, 0.68 mm, 0.7 mm, 0.74 mm, 0.78 mm, 0.82 mm, 0.85 mm, 0.9 mm, 0.95 mm, 0.98 mm, 1 mm, 1.5 mm, 1.8 mm, 1.9 mm, 2 mm, 2.2 mm, 2.5 mm, 2.8 mm, etc.

[0008] Further preferably, the X-ray diffraction pattern of the thermally conductive film satisfies: 10°≤2θ GFF -2θ GO ≤20°.

[0009] Further preferably, the X-ray diffraction pattern of the thermally conductive film satisfies: 12°≤2θ GFF -2θ GO ≤17.5°.

[0010] Thermal conductive film X-ray diffraction test method:

[0011] In the present invention, XRD (X-ray Diffraction) can be used with a Japanese Rigaku Ultima IV tester, using a copper target as the test target, a scanning range of 5-90°, and an X-ray excitation source at a scanning speed of 10° / min to test the crystallinity of the sample.

[0012] In the present invention, the degree of crystallinity change of graphene oxide after coating, foaming, carbonization and graphitization will directly affect the final micro-nano cavity thermal conductive film plane thermal conductivity. After a lot of testing and research, the inventors found that when the X-ray diffraction pattern of the thermal conductive film meets 10°≤2θ GFF -2θ GO When the angle is ≤20°, the final micro-nano cavity thermal conductive film in-plane thermal diffusion coefficient can be ≥500mm 2 / s. The applicant speculates that the reason for achieving such a result is that the crystallinity difference between graphene oxide and micro-nano cavity thermal conductive film is small, and accordingly, the 2θ GO The value is relatively large, which is reflected in the fact that the content of oxygen-containing functional groups in its structure is relatively small, so that the atomic defects generated in the carbonization stage are relatively small, and then its atomic structure can be quickly repaired in the graphitization stage. The obtained micro-nano cavity thermal conductive film has high structural integrity and fast heat transfer rate; and the inventors found that if 2θ GFF -2θ GOWhen the angle is greater than 20°, the in-plane thermal conductivity of the micro-nano cavity thermal conductive film decreases. The applicant speculates that this is due to the significant difference in crystallinity between the two. The large number of oxygen-containing functional groups on the surface of graphene oxide leads to a large number of atomic defects during the carbonization stage, which cannot be fully repaired in time during the graphitization stage. The presence of such defects directly affects the transfer of heat within the structure, resulting in a significant decrease in the in-plane thermal conductivity of the micro-nano cavity thermal conductive film.

[0013] In some preferred embodiments, a foaming composition is used in the foaming process; the foaming composition is selected from at least one of hydrazine hydrate, sodium hydrogen borate, dimethylhydrazine, and thiourea; preferably hydrazine hydrate.

[0014] Further preferably, the mass concentration of the foaming composition is 0.05~80%, for example, 0.1%, 0.5%, 1%, 5%, 10%, 18%, 23%, 34%, 45%, 52%, 60%, 65%, 75%, etc.; further preferably, the mass concentration of the foaming composition is 1~10%, for example, 0.1%, 0.5%, 1%, 1.5%, 2%, 3%, 4%, 5%, 7%, 8%, 9%, 10%, etc.

[0015] In some preferred embodiments, the intermediate 1 is formed after the foaming, and the peak area relationship of the intermediate 1 in the XPS spectrum is as follows: 20%≤AreaC-O / (AreaC-C+C=C)≤60%, where AreaC-O and AreaC-C+C=C are the peak areas of the carbon-oxygen single bond and the sum of the carbon-carbon single bond and the carbon-carbon double bond of C 1s in the XPS spectrum, respectively.

[0016] In the present invention, XPS (X-ray photoelectron spectroscopy) can be performed using a Thermo Scientific NEXSA XPS tester. The sample is placed in a vacuum of approximately 5*10 -9 In the analysis chamber at mbar, a monochromatized A1 Kα source is used to measure the chemical composition of the sample.

[0017] In the present invention, residual O atoms remain in the intermediate 1 formed after foaming. After extensive testing and research, the inventors discovered that when the XPS spectrum of the foamed intermediate 1 shows a ratio of 20% ≤ AreaC-O / (AreaC-C+C=C) ≤ 60%, 80% of the final thermally conductive film can achieve a compressive rebound stress of 0.01-0.23 MPa. The applicants speculate that this phenomenon occurs because during the foaming process, the foaming composition strongly interacts with oxygen atoms on the surface of graphene oxide (primarily oxygen atoms in the CO structure), converting and generating large amounts of gases such as CO, CO2, and NH3, which accumulate between the graphene layers. This causes a rapid increase in local gas pressure, opening up the interlayers to form cavities. Simultaneously, stable hydrogen bonds form between the graphene layers, ensuring the formation of stable micro-nanocavities in the resulting thermally conductive film. When subjected to external compressive stress, this stable cavity structure quickly dissipates the stress, thereby ensuring a rebound stress of 0.2 MPa. Furthermore, the inventors discovered that if the AreaC-O / (AreaC-C+C=C) ratio after foaming is greater than 60%, it is speculated that during the foaming process, the foaming composition reacts weakly with the oxygen atoms on the graphene oxide surface, the amount of gas conversion is small, and sufficient gas pressure cannot be generated locally. The graphene layers are not fully opened, that is, the pore structure formation effect is poor. Correspondingly, fewer hydrogen bonds are formed between the graphene layers, and the connection between the graphene layers is weak, resulting in stress concentration when subjected to external forces, causing a significant decrease in compression rebound performance. In addition, the inventors also found that when the AreaC-O / (AreaC-C+C=C) ratio after foaming is less than 20%, the rebound stress is extremely low, less than 0.01MPa. It is speculated that during the foaming process, the foaming composition reacts too fully with the oxygen atoms on the graphene oxide surface, the local gas pressure between the graphene layers exceeds the bearing capacity of the graphene structure, and the pore structure is severely damaged, resulting in the inability to rebound after being compressed by external forces.

[0018] In some preferred embodiments, the carbon content of the graphene oxide is 60-70 wt %.

[0019] In the present invention, the graphene oxide used was purchased from Yunnan Yuntian Mo Rui Technology Co., Ltd.

[0020] In some preferred embodiments, the carbon content of the thermally conductive film obtained after graphitization is 1 to 2 times that of graphene oxide; further preferably, the carbon content of the thermally conductive film obtained after graphitization is 1.2 to 1.7 times that of graphene oxide.

[0021] In some preferred embodiments, the foaming temperature is 25-60°C, for example, 25°C, 30°C, 33°C, 37°C, 40°C, 42°C, 45°C, 48°C, 50°C, 51°C, 55°C, 57°C, 59°C, etc.

[0022] In some preferred embodiments, the foaming time is 1 to 180 s, for example, 1 s, 3 s, 5 s, 10 s, 15 s, 20 s, 30 s, 50 s, 60 s, 90 s, 120 s, 150 s, etc.; more preferably, the foaming time is 1 to 5 s.

[0023] In the present invention, the inventors found that the foaming time has a great influence on the morphology of the intermediate 1. If the foaming time is prolonged, the structure of the intermediate 1 will be destroyed and fall apart, and a micro-nano cavity thermal conductive film with a dense pore structure cannot be prepared.

[0024] The intermediate 1 obtained after foaming is a wet graphene foam, and the obtained intermediate 1 is carbonized and then graphitized.

[0025] In some preferred embodiments, the carbonization temperature is 900~1300℃, for example, 900℃, 1000℃, 1080℃, 1100℃, 1150℃, 1200℃, 1250℃, etc.; preferably, the carbonization temperature is 1200~1300℃; more preferably, the carbonization temperature is 1200℃, 1300℃.

[0026] As a preferred solution, the carbonization temperature is 1200°C.

[0027] As a preferred solution, the carbonization temperature is 1300°C.

[0028] In some preferred embodiments, the graphitization temperature is 2000~3000℃, for example, 2100℃, 2230℃, 2250℃, 2300℃, 2345℃, 2380℃, 2420℃, 2440℃, 2460℃, 2500℃, 2550℃, 2600℃, 2750℃, 2880℃, 2900℃, 2950℃, etc.; further preferably, the graphitization temperature is 2900℃~3000℃; more preferably, the graphitization temperature is 2900℃ or 30000℃.

[0029] In some preferred embodiments, the surface density of the graphene micro-nano cavity thermal conductive film is 0.002 g / cm 2 ~0.2g / cm 2 Preferably, the surface density is 0.05 g / cm 2 ~0.2g / cm 2 ;

[0030] In some preferred embodiments, the porosity of the graphene micro-nano cavity thermally conductive film is 90-98%. In the present invention, the porosity of the graphene micro-nano cavity thermally conductive film is related to the density of the thermally conductive film.

[0031] Porosity φ = 1-density of micro-nano cavity thermal conductive film / theoretical density of graphite × 100%.

[0032] The theoretical density of graphite is 2.0g / cm 3 or 2.1 g / cm 3 .

[0033] In some preferred embodiments, the preparation process of the graphene micro-nano cavity thermal conductive film is as follows:

[0034] A graphene oxide coating film with a carbon content of 60-70 wt% is placed in a reaction vessel and reacted with a foaming composition, preferably hydrazine hydrate, at a temperature of 25-60°C for 1-180 seconds, preferably 1-5 seconds, to obtain wet graphene foam, which is intermediate 1. The foam is then dried in a drying oven. The intermediate is then subjected to high-temperature carbonization at 900-1300°C, preferably 1200°C or 1300°C, and graphitization at 2000-3000°C, preferably 2900°C or 3000°C, to obtain the intermediate.

[0035] The second aspect of the present invention provides an application of a graphene micro-nano cavity thermal conductive film for use in pressure sensors, supercapacitors, fuel cells, carbon catalytic materials, switches, and optical modules.

[0036] A third aspect of the present invention provides a graphene micro-nano cavity phase change temperature evaporating plate, comprising the graphene micro-nano cavity thermal conductive film and a phase change material.

[0037] In some preferred embodiments, the wall thickness of the graphene micro-nano cavity thermal conductive film is 0.1-3.0 μm.

[0038] The wall thickness is measured by scanning electron microscope (SEM), the SEM machine model is JEOL JSM-7610F, the test condition is to cut the sample cross section for low vacuum testing, and the magnification is 1000-2000 times.

[0039] In some preferred embodiments, the phase change material includes paraffin wax. Beneficial effects

[0040] 1. The X-ray diffraction pattern of the graphene micro-nano cavity thermal conductive film prepared by the present invention satisfies 10°≤2θ GFF -2θ GO≤20°; indicating that the graphene micro-nano cavity thermal conductive film obtained by the method of the present invention has a regular structure and a perfect crystal structure, further indicating that the graphene micro-nano cavity thermal conductive film obtained by the present invention has excellent thermal conductivity and the planar thermal conductivity coefficient after compression by 80% can reach more than 300 W / m·K;

[0041] 2. The XPS spectrum of the intermediate 1 formed after foaming the graphene micro-nanocavity thermal conductive film prepared by the present invention satisfies the following conditions: 20%≤AreaC-O / (AreaC-C+C=C)≤60%, which can achieve a compression rebound stress of 80% of the final thermal conductive film within the range of 0.01~0.2MPa.

[0042] 3. The surface density of the graphene micro-nano cavity thermal conductive film prepared by the present invention is 0.002g / cm 2 ~0.2g / cm 2 , ensuring the application of thermal conductive films in pressure sensors, supercapacitors, fuel cells, carbon catalytic materials, switches, and optical modules;

[0043] 4. The graphene micro-nanocavity thermal conductive film obtained by the present invention has a fluffy and porous microstructure and uniform and stable performance. It can also be used in combination with other materials in the subsequent use process. It has a wide range of applications, great prospects, and diversified application fields. It is a rare high thermal conductivity and electrical conductivity material on the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIG1 is an X-ray diffraction pattern of GO, a raw material for the graphene micro-nanocavity thermal conductive film, prepared in Example 1 of the present invention;

[0045] FIG2 is an X-ray diffraction pattern of the graphene micro-nano cavity thermal conductive film GFF prepared in Example 1 of the present invention;

[0046] FIG3 is a 600-fold (×600) SEM image of the graphene micro-nanocavity thermal conductive film prepared in Example 1 of the present invention;

[0047] FIG4 is a 2000-fold (×2000) SEM image of the graphene micro-nanocavity thermal conductive film prepared in Example 1 of the present invention;

[0048] FIG5 is a 5000-fold (×5000) SEM image of the graphene micro-nanocavity thermal conductive film prepared in Example 1 of the present invention;

[0049] FIG6 is an XPS spectrum of intermediate 1 during the preparation of the graphene micro-nanocavity thermal conductive film according to Example 1 of the present invention;

[0050] FIG7 is an XPS spectrum of the graphene micro-nano cavity thermal conductive film GFF prepared in Example 1 of the present invention. Modes for Carrying Out the Invention

[0051] In the present invention, X-ray diffraction was performed using a Japanese Rigaku Ultima IV tester, with a copper target as the test target, a scanning range of 5-90°, and a scanning speed of 10° / min.

[0052] XPS (X-ray photoelectron spectroscopy) was performed using an ESCA lab 250 XPS instrument. The sample was placed at a base pressure of 3 × 10 -8 In the Pa energy analysis mode, A1 Kα 1486.8eV X-rays were used as the excitation source to test the chemical composition of the samples;

[0053] The results were obtained by scanning electron microscope (SEM) testing. The SEM model was JEOL JSM-7610F. The test conditions were to cut the sample cross section for low vacuum testing at a magnification of 1000-5000 times. Example 1

[0054] A graphene micro-nano cavity thermally conductive film, wherein the thickness of the graphene thermally conductive film is tested according to ASTM D374, and the thickness obtained by the test is: 0.348 mm;

[0055] The X-ray diffraction pattern of the thermally conductive film satisfies: 2θ GFF -2θ GO =16.2°, the XRD test results of GO and GFF are shown in Figures 1 and 2 respectively;

[0056] The peak area relationship of the intermediate 1 in the XPS spectrum is as follows: AreaC-O / (AreaC-C+C=C)=43.74%. The test results are shown in Figures 6 and 7;

[0057] The preparation process for the graphene micro-nanocavity thermal conductive film is as follows: a graphene oxide coating with a carbon content of 66.51 wt% is placed in a reaction vessel and reacted with a foaming composition containing hydrazine hydrate at a concentration of 3%. The reaction temperature is 25°C and the reaction time is 3 seconds. A wet graphene foam (Intermediate 1) is obtained. The foam is then dried in a drying oven. The resulting product is then subjected to a high-temperature carbonization treatment at 1200°C and a graphitization treatment at 2900°C.

[0058] Graphene oxide with a carbon content of 66.51 wt% was purchased from Yunnan Yuntian Mo Rui Technology Co., Ltd.

[0059] The carbon content of the thermally conductive film obtained after graphitization is 1.489 times that of graphene oxide;

[0060] The test method for the planar thermal conductivity of the graphene micro-nano cavity thermal conductive film is ASTM E1461-13. The test shows that the planar thermal conductivity after compression by 80% is: 340.89 W / mK.

[0061] The test method for 80% rebound stress of the graphene micro-nano cavity thermal conductive film is GB / T 8813, and the 80% rebound stress obtained by the test is: 0.018MPa.

[0062] The wall thickness of the graphene thermal conductive film was characterized by SEM, and the obtained wall thickness was: 0.83 μm, as shown in Figures 3, 4 and 5.

[0063] The present invention also provides a micro-nano cavity thermal conductive film phase change temperature equalizing plate, comprising the graphene micro-nano cavity thermal conductive film prepared in Example 1 and a phase change material, wherein the phase change material is paraffin, and the phase change peak temperature of the paraffin is 45±2°C, and the thermal enthalpy value is 210±10J / g.

[0064] The preparation method of the graphene micro-nano cavity phase change temperature averaging plate comprises the following steps: (1) placing the paraffin block in an 80°C vacuum drying oven to heat and melt it into liquid; (2) completely immersing the graphene micro-nano cavity thermal conductive film in liquid paraffin, and continuously immersing it for 10 minutes under a vacuum condition of -0.1MPa so that the paraffin liquid and the graphene micro-nano cavity thermal conductive film are completely compounded; (3) taking out the filled graphene micro-nano cavity thermal conductive film, and vertically placing it in an 80°C forced air drying oven, and the process lasts for at least 30 minutes to remove the paraffin liquid remaining on the surface of the micro-nano cavity thermal conductive film; (4) compounding the drained paraffin with the graphene micro-nano cavity thermal conductive film material, and cooling it at room temperature for 10 minutes to obtain the graphene micro-nano cavity phase change temperature averaging plate.

[0065] The obtained graphene micro-nano cavity phase change temperature plate has a phase change peak temperature of 43.7° C., a thermal enthalpy value of 158.06 J / g, and a plane thermal conductivity coefficient of 68.79 W / mK.

[0066] The graphene micro-nano cavity heat-conducting film provided by the present invention is used in fuel cells. Example 2

[0067] A graphene micro-nano cavity thermally conductive film, wherein the thickness of the graphene thermally conductive film is tested according to ASTM D374, and the thickness obtained by the test is: 0.447 mm;

[0068] The X-ray diffraction pattern of the thermally conductive film satisfies 2θ GFF -2θ GO =16.4°;

[0069] The relationship of the peak areas of the intermediate 1 in the XPS spectrum is as follows: Area C-O / (Area C-C + C=C) = 35.42%;

[0070] The preparation process for the graphene micro-nanocavity thermal conductive film is as follows: a graphene oxide coating with a carbon content of 66.51 wt% is placed in a reaction vessel and reacted with a foaming composition, hydrazine hydrate, at a concentration of 5%. The reaction temperature is 25°C and the reaction time is 3 seconds. A wet graphene foam, intermediate 1, is obtained. The foam is then dried in a drying oven. The resulting product is then subjected to a high-temperature carbonization treatment at 1300°C and a graphitization treatment at 2900°C.

[0071] Graphene oxide with a carbon content of 66.51 wt% was purchased from Yunnan Yuntian Mo Rui Technology Co., Ltd.

[0072] The carbon content of the thermally conductive film obtained after graphitization is 1.498 times that of graphene oxide;

[0073] The test method for the planar thermal conductivity of the graphene micro-nano cavity thermal conductive film is ASTM E1461-13. The planar thermal conductivity after compression of 80% obtained by the test is: 352.71 W / mK.

[0074] The test method for 80% rebound stress of the graphene micro-nano cavity thermal conductive film is GB / T 8813, and the 80% rebound stress obtained by the test is: 0.015MPa.

[0075] The graphene micro-nano cavity thermal conductive film was characterized by SEM, and the wall thickness was 0.71 μm.

[0076] The present invention also provides a micro-nano cavity thermal conductive film phase change temperature equalizing plate, comprising the graphene micro-nano cavity thermal conductive film prepared in Example 2 and a phase change material, wherein the phase change material is paraffin, the phase change peak temperature is 40±2°C, and the thermal enthalpy value is 220±10J / g. The preparation method of the graphene micro-nano cavity phase change temperature averaging plate comprises the following steps: (1) placing the paraffin block in an 80°C vacuum drying oven to heat and melt it into liquid; (2) completely immersing the graphene micro-nano cavity thermal conductive film in liquid paraffin, and continuously immersing it for 10 minutes under a vacuum condition of -0.1MPa so that the paraffin liquid and the graphene micro-nano cavity thermal conductive film are completely compounded; (3) taking out the filled graphene micro-nano cavity thermal conductive film, and vertically placing it in an 80°C forced air drying oven, and the process lasts for at least 30 minutes to remove the paraffin liquid remaining on the surface of the micro-nano cavity thermal conductive film; (4) compounding the drained paraffin with the graphene micro-nano cavity thermal conductive film material, and cooling it at room temperature for 10 minutes to obtain the graphene micro-nano cavity phase change temperature averaging plate.

[0077] The obtained graphene micro-nano cavity phase change temperature plate has a phase change peak temperature of 39.06° C., a thermal enthalpy value of 173.81 J / g, and a plane thermal conductivity coefficient of 59.17 W / mK.

[0078] The graphene micro-nano cavity heat-conducting film provided by the present invention is used in carbon catalytic materials. Example 3

[0079] A graphene micro-nano cavity thermally conductive film, wherein the thickness of the graphene thermally conductive film is tested according to ASTM D374, and the thickness obtained by the test is: 0.161 mm;

[0080] The X-ray diffraction pattern of the thermally conductive film satisfies 2θ GFF -2θ GO =17.1°;

[0081] The relationship of the peak areas of the intermediate 1 in the XPS spectrum is as follows: Area C-O / (Area C-C + C=C) = 31.41%;

[0082] The preparation process for the graphene micro-nanocavity thermal conductive film is as follows: a graphene oxide coating with a carbon content of 66.51 wt% is placed in a reaction vessel. A foaming composition, hydrazine hydrate, is reacted at a 1% concentration, a temperature of 25°C, and a reaction time of 3 seconds to produce wet graphene foam (Intermediate 1). The foam is then dried in a drying oven. The resulting product is then subjected to subsequent high-temperature carbonization at 1200°C and graphitization at 3000°C.

[0083] The carbon content of the thermally conductive film obtained after graphitization is 1.486 times that of graphene oxide;

[0084] The test method for the planar thermal conductivity of the graphene micro-nano cavity thermal conductive film is ASTM E1461-13. The test shows that the planar thermal conductivity after compression by 80% is: 313.23 W / mK.

[0085] The test method for 80% rebound stress of graphene micro-nano cavity thermal conductive film is GB / T 8813, and the 80% rebound stress obtained by the test is: 0.01 MPa

[0086] The graphene micro-nano cavity thermal conductive film was characterized by SEM, and the wall thickness was 0.93 μm;

[0087] The present invention also provides a micro-nano cavity thermal conductive film phase change temperature equalizing plate, comprising the graphene micro-nano cavity thermal conductive film prepared in Example 3 and a phase change material, wherein the phase change material is paraffin, the phase change peak temperature is 40±2°C, and the thermal enthalpy value is 220±10J / g.

[0088] The preparation method of the graphene micro-nano cavity phase change temperature averaging plate comprises the following steps: (1) placing the paraffin block in an 80°C vacuum drying oven to heat and melt it into liquid; (2) completely immersing the graphene micro-nano cavity thermal conductive film in liquid paraffin, and continuously immersing it for 10 minutes under a vacuum condition of -0.1MPa so that the paraffin liquid and the graphene micro-nano cavity thermal conductive film are completely compounded; (3) taking out the filled graphene micro-nano cavity thermal conductive film, and vertically placing it in an 80°C forced air drying oven, and the process lasts for at least 30 minutes to remove the paraffin liquid remaining on the surface of the micro-nano cavity thermal conductive film; (4) compounding the drained paraffin with the graphene micro-nano cavity thermal conductive film material, and cooling it at room temperature for 10 minutes to obtain the graphene micro-nano cavity phase change temperature averaging plate.

[0089] The obtained graphene micro-nano cavity phase change temperature plate has a phase change peak temperature of 39.14° C., a thermal enthalpy value of 184.89 J / g, and a plane thermal conductivity coefficient of 82.21 W / m·K.

[0090] The graphene micro-nano cavity heat-conducting film provided by the present invention is used in an optical module. Example 4

[0091] A graphene micro-nano cavity thermally conductive film, wherein the thickness of the graphene thermally conductive film is tested according to ASTM D374, and the thickness obtained by the test is: 1.561 mm;

[0092] The X-ray diffraction pattern of the thermally conductive film satisfies 2θ GFF -2θ GO =17.6°;

[0093] The relationship of the peak areas of the intermediate 1 in the XPS spectrum is as follows: Area C-O / (Area C-C + C=C) = 36.6%;

[0094] The preparation process for the graphene micro-nanocavity thermal conductive film is as follows: a graphene oxide coating with a carbon content of 66.51 wt% is placed in a reaction vessel and reacted with a foaming composition, hydrazine hydrate, at a concentration of 15%. The reaction temperature is 25°C and the reaction time is 10 seconds. A wet graphene foam, intermediate 1, is obtained. The foam is then dried in a drying oven. The resulting product is then subjected to a high-temperature carbonization treatment at 1200°C and a graphitization treatment at 2900°C.

[0095] Graphene oxide with a carbon content of 66.51 wt% was purchased from Yunnan Yuntian Mo Rui Technology Co., Ltd.

[0096] The carbon content of the thermally conductive film obtained after graphitization is 1.664 times that of graphene oxide;

[0097] The test method for the planar thermal conductivity of the graphene micro-nano cavity thermal conductive film is ASTM E1461-13. The test shows that the planar thermal conductivity after compression by 80% is: 342.72W / mK.

[0098] The test method for 80% rebound stress of the graphene micro-nano cavity thermal conductive film is GB / T 8813, and the 80% rebound stress obtained by the test is: 0.16 MPa.

[0099] The graphene micro-nano cavity thermal conductive film was characterized by SEM, and the wall thickness was 1.12 μm;

[0100] The present invention also provides a micro-nano cavity thermal conductive film phase change temperature equalizing plate, comprising the graphene micro-nano cavity thermal conductive film prepared in Example 4 and a phase change material, wherein the phase change material is paraffin, the phase change peak temperature is 40±2°C, and the thermal enthalpy value is 220±10J / g.

[0101] The preparation method of the graphene micro-nano cavity phase change temperature averaging plate comprises the following steps: (1) placing the paraffin block in an 80°C vacuum drying oven to heat and melt it into liquid; (2) completely immersing the graphene micro-nano cavity thermal conductive film in liquid paraffin, and continuously immersing it for 10 minutes under a vacuum condition of -0.1MPa so that the paraffin liquid and the graphene micro-nano cavity thermal conductive film are completely compounded; (3) taking out the filled graphene micro-nano cavity thermal conductive film, and vertically placing it in an 80°C forced air drying oven, and the process lasts for at least 30 minutes to remove the paraffin liquid remaining on the surface of the micro-nano cavity thermal conductive film; (4) compounding the drained paraffin with the graphene micro-nano cavity thermal conductive film material, and cooling it at room temperature for 10 minutes to obtain the graphene micro-nano cavity phase change temperature averaging plate.

[0102] The obtained graphene micro-nano cavity phase change temperature plate has a phase change peak temperature of 38.42° C., a thermal enthalpy value of 166.78 J / g, and a plane thermal conductivity coefficient of 58.48 W / m·K.

[0103] The graphene micro-nano cavity heat-conducting film provided by the present invention is used in carbon catalytic materials. Example 5

[0104] A graphene micro-nano cavity thermally conductive film, wherein the thickness of the graphene thermally conductive film is tested according to ASTM D374, and the thickness obtained by the test is: 0.341 mm;

[0105] The X-ray diffraction pattern of the thermally conductive film satisfies 2θ GFF -2θ GO =15.7°;

[0106] The relationship of the peak areas of the intermediate 1 in the XPS spectrum is as follows: Area C-O / (Area C-C + C=C) = 40.6%;

[0107] The preparation process for the graphene micro-nanocavity thermal conductive film is as follows: a graphene oxide coating with a carbon content of 66.51 wt% is placed in a reaction vessel and reacted with a foaming composition, sodium borate, at a concentration of 3%. The reaction temperature is 25°C and the reaction time is 3 seconds. A wet graphene foam, intermediate 1, is obtained. The foam is then dried in a drying oven. The resulting product is then subjected to a high-temperature carbonization treatment at 1200°C and a graphitization treatment at 2900°C.

[0108] The carbon content of the thermally conductive film obtained after graphitization is 1.336 times that of graphene oxide;

[0109] The test method for the planar thermal conductivity of the graphene micro-nano cavity thermal conductive film is ASTM E1461-13. The test shows that the planar thermal conductivity of the film at 80% compression is 336.45 W / mK.

[0110] The test method for 80% rebound stress of the graphene micro-nano cavity thermal conductive film is GB / T 8813, and the 80% rebound stress obtained by the test is: 0.13MPa.

[0111] The graphene micro-nano cavity thermal conductive film was characterized by SEM, and the wall thickness was 1.16 μm;

[0112] The present invention also provides a micro-nano cavity thermal conductive film phase change temperature equalizing plate, comprising the graphene micro-nano cavity thermal conductive film prepared in Example 5 and a phase change material, wherein the phase change material is paraffin, the phase change peak temperature is 40±2°C, and the thermal enthalpy value is 220±10J / g.

[0113] The preparation method of the graphene micro-nano cavity phase change temperature averaging plate comprises the following steps: (1) placing the paraffin block in an 80°C vacuum drying oven to heat and melt it into liquid; (2) completely immersing the graphene micro-nano cavity thermal conductive film in liquid paraffin, and continuously immersing it for 10 minutes under a vacuum condition of -0.1MPa so that the paraffin liquid and the graphene micro-nano cavity thermal conductive film are completely compounded; (3) taking out the filled graphene micro-nano cavity thermal conductive film, and vertically placing it in an 80°C forced air drying oven, and the process lasts for at least 30 minutes to remove the paraffin liquid remaining on the surface of the micro-nano cavity thermal conductive film; (4) compounding the drained paraffin with the graphene micro-nano cavity thermal conductive film material, and cooling it at room temperature for 10 minutes to obtain the graphene micro-nano cavity phase change temperature averaging plate.

[0114] The obtained graphene micro-nano cavity phase change temperature plate has a phase change peak temperature of 39.12° C., a thermal enthalpy value of 176.78 J / g, and a plane thermal conductivity coefficient of 28.18 W / m·K. Example 6

[0115] A company's HFC-GR series of thermally conductive polyurethane foam on the market has a thickness of 0.5-5 mm. The thermal conductivity coefficient after compression by 80% is measured to be only >1.0 W / m·K.

[0116] The process parameters of the embodiment and the parameters of the thermal conductive film are specifically shown in Table 1 and Table 2;

[0117] Table 1:

[0118]

[0119] Table 2:

[0120]

[0121] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A graphene micro-nano cavity thermal conductive film, characterized in that: The method is obtained by coating graphene oxide to form a film, reducing and foaming, carbonizing, and graphitizing; The thickness of the thermally conductive film is 0.15-3 mm; The X-ray diffraction spectrum of the thermally conductive film satisfies: 10°≤2θ GFF -2θ GO ≤20°; More preferably, the X-ray diffraction pattern of the thermally conductive film satisfies: 12°≤2θ GFF -2θ GO ≤17.5°; 2θ GO is the first diffraction angle of graphene oxide 2θ; 2θ GFF is the first diffraction angle 2θ of the micro-nano cavity thermal conductive film.

2. The graphene micro-nano cavity thermal conductive film according to claim 1, characterized in that: A foaming composition is used in the foaming process; the foaming composition is selected from at least one of hydrazine hydrate, sodium hydrogen borate, dimethylhydrazine and thiourea.

3. The graphene micro-nano cavity thermal conductive film according to claim 2, characterized in that: The mass concentration of the foaming composition is 0.05-80%; preferably, the mass concentration is 1-10%.

4. The graphene micro-nano cavity thermal conductive film according to any one of claims 1 to 3, characterized in that: The intermediate 1 is formed after the foaming, and the peak area relationship of the intermediate 1 in the XPS spectrum is as follows: 20%≤AreaC-O / (AreaC-C+C=C)≤60%, and AreaC-O and AreaC-C+C=C are the peak areas of the carbon-oxygen single bond and the sum of the carbon-carbon single bond and the carbon-carbon double bond of C 1s in the XPS spectrum, respectively.

5. The graphene micro-nano cavity thermal conductive film according to claim 1, characterized in that: The carbon content of the graphene oxide is 60-70wt%.

6. The graphene micro-nano cavity thermal conductive film according to claim 1 or 5, characterized in that: The carbon content of the thermally conductive film obtained after graphitization is 1 to 2 times that of graphene oxide; preferably, the carbon content of the thermally conductive film obtained after graphitization is 1.2 to 1.7 times that of graphene oxide.

7. The graphene micro-nano cavity thermal conductive film according to claim 6, characterized in that: The graphitization temperature is 2000-3000°C.

8. An application of the graphene micro-nano cavity thermal conductive film according to any one of claims 1 to 7 in a pressure sensor, a supercapacitor, a fuel cell, a carbon catalytic material, a switch, and an optical module.

9. A graphene micro-nano cavity phase change temperature plate, characterized in that: It comprises the graphene micro-nano cavity thermal conductive film and phase change material as described in any one of claims 1 to 7.

10. The phase change temperature equalizing plate according to claim 9, characterized in that: The wall thickness of the graphene micro-nano cavity thermal conductive film is 0.1-3.0 μm.

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