Oversized graphene film and graphitization method thereof

Abstract

The invention discloses an oversized heat conduction film and a graphitization method thereof. The size of the oversized heat conduction film in the length or width direction is 0.3-3 m, the material area is 0.1-9 m < 2 >, the thickness is 20-800 microns, and the heat conductivity in the plane direction is 700-1800 W / mK. An oversized graphene film is wound and wrapped on the periphery of a columnar graphite heating electrode of a graphitization furnace, an annular supporting body made of graphite is used for providing support for the oversized graphene film on the outside, and heat generated by the columnar graphite heating electrode of the graphitization furnace is used for carrying out graphitization treatment on the oversized graphene film.

Description

Technical Field

[0001] The invention relates to the field of heat-conducting materials, in particular to an oversized graphene film and a graphitization method thereof. Background Art

[0002] With the advent of the 5G era, graphene film has also become a potential new star in the thermal management of the electronics industry. At present, some large electronic products such as display screens also have heat dissipation requirements. However, due to the size constraints of graphene films and their graphitization furnaces, it is difficult to produce graphene films of super-large sizes. How to achieve the graphitization of super-large-sized graphene films has become an urgent problem to be solved. In this regard, this application specifically proposes a super-large-sized graphene film and its graphitization method. Summary of the invention

[0003] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides an ultra-large-sized graphene film and a graphitization method thereof, and the technical solution to the problem is to include the following steps: Step 1: After the graphene oxide and graphene are uniformly mixed in a dispersant, the mixture is coated on a substrate and dried to form a graphene oxide film; Step 2: Cut the graphene oxide film obtained in step 1 into corresponding sizes according to the outer surface size of the columnar graphite heating electrode of the graphitization furnace; Step 3, pre-treating the graphene film cut in step 2 by calcining under a protective atmosphere to obtain an oversized pre-treated graphene film; Step 4: sandwiching the super-large-sized pre-treated graphene film after calcination pre-treatment between two layers of graphite paper; Step 5: The graphite paper obtained in step 4 and the pre-treated graphene film (2) are wound together and wrapped around the periphery of the graphitization furnace columnar graphite heating electrode (1) of corresponding size and specifications, and the outer edge of the graphite paper is fixed with adhesive tape; Step 6: Two annular support bodies (3) having a supporting function are mounted on the outermost part of the columnar graphite heating electrode (1) of the graphitization furnace, and the two annular support bodies (3) are respectively located at two ends of the columnar graphite heating electrode (1) of the graphitization furnace; Step 7, cover the insulation material, and energize both ends of the graphite heating electrode (1) of the graphitization furnace to heat the material to 2500-3100°C. After power transmission is completed, the material goes through the steps of pressure maintenance, temperature reduction, and furnace discharge in sequence to complete the graphitization process and obtain an ultra-large-sized graphitized film. Step 8: Compact the super-sized graphitized film obtained in step 4 to obtain a super-sized graphene film.

[0004] Preferably, the diameter of the columnar graphite heating electrode of the graphitization furnace is 200-850 mm.

[0005] Preferably, the graphene film has a thickness of 20-800 μm.

[0006] Preferably, the length or width of the super-sized graphene film material is 0.3-3m, and the material area is 0.1-9m 2 .

[0007] The beneficial effects of the present invention are: When in use, the present application cuts the oversized graphene film according to the length and diameter of the columnar graphite heating electrode of the graphitization furnace, and then attaches and stacks the oversized graphene film on the periphery of the graphite column, and uses an annular support body made of graphite material to provide support for the oversized graphene film on the outside. The heat generated by the columnar graphite heating electrode of the graphitization furnace is used to graphitize the oversized graphene film. The graphitization process has less energy loss, saves energy, and greatly reduces the graphitization cost of the oversized graphene film. The present application has a simple structure, is easy to use, and has strong practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a three-dimensional schematic diagram of the present invention.

[0009] Reference numerals 1. Graphitization furnace columnar graphite heating electrode, 2. Super large size pre-treated graphene film, 3. Ring support. DETAILED DESCRIPTION

[0010] The following is combined with Figure 1 The specific implementation modes of the present invention are further described in detail.

[0011] Example 1, select the super-large pre-treated graphene film pre-treated by calcination at 2000℃, the film thickness is 100μm, select the φ350 graphitization furnace columnar graphite heating electrode with a length of 1.6m and a circumference of 1.1m, the graphite paper width is 1m and the graphene film is 0.8m wide, and the lengths are 3.5m and 3m respectively. The super-large pre-treated graphene film and the upper and lower layers of graphite paper are wound around the periphery of the columnar graphite heating electrode of the graphitization furnace. The two prepared semi-circular rings with a thickness of 50mm of graphite material are used as the annular support 3, and one semi-circular ring is first placed in the graphitization furnace. After the columnar graphite heating electrode wound with graphite paper and super-large graphene film is placed, the remaining semi-circular ring is placed and meshed with the previous semi-circular ring to form an annular support 3. Add the insulation material, energize both ends of the columnar graphite heating electrode of the graphitization furnace, and heat the material to 2800℃. Compacting oversized graphitized membranes to a density of 2.0 g / cm 3 Obtain an ultra-large-sized graphene film.

[0012] The above-mentioned ultra-large-size graphene film has a length of 0.8m, a width of 3m and an area of ​​2.4㎡; a thickness of 100 microns, and a thickness uniformity difference of ≤±5μm; a thermal conductivity of the material of 1400W / mK, and a thermal conductivity uniformity difference of ≤±20W / mK.

[0013] Example 2: Select an oversized pretreated graphene film pretreated at 2000°C, the film thickness is 200μm, select a φ800 graphitization furnace columnar graphite heating electrode with a length of 2.7m and a circumference of 2.5m, the graphite paper width is 2.6m and the graphene film is 2.5m wide, and the lengths are 3.5m and 3m respectively. The oversized pretreated graphene film and the upper and lower layers of graphite paper are wound around the periphery of the columnar graphite heating electrode of the graphitization furnace. The two prepared semicircular rings of graphite material with a thickness of 50mm are used as an annular support 3, and one semicircular ring is first placed in the graphitization furnace. After the columnar graphite heating electrode wound with graphite paper and oversized graphene film is placed, the remaining semicircular ring is placed and meshed with the previous semicircular ring to form an annular support 3. Add the insulation material, energize both ends of the columnar graphite heating electrode of the graphitization furnace, and heat the material to 3000°C. Compacting oversized graphitized membranes to a density of 2.0 g / cm 3 Obtain an ultra-large-sized graphene film.

[0014] The above-mentioned ultra-large-size graphene film has a length of 3m, a width of 2.5m and an area of ​​7.5㎡; a thickness of 200 microns, and a thickness uniformity difference of ≤±10μm; a thermal conductivity of the material of 1600W / mK, and a thermal conductivity uniformity difference of ≤±30W / mK.

[0015] In addition, it should be understood that this specification is described in accordance with the implementation methods. However, not every implementation method contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should read the specification as a whole. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An ultra-large-size graphene film, characterized in that: The graphene film has a thickness of 20-800 μm and a density of 1.0-2.3 g / cm 3 The tensile strength of the material is 5-20 MPa, and the thermal conductivity of the material along the plane direction is 700-1800 W / mK; the length or width of the graphene film material is 0.3-3m, and the material area is 0.1-9m 2 .

2. The super-large-size graphene film according to claim 1, characterized in that: The preparation method comprises the following steps: Step 1: After the graphene oxide and graphene are uniformly mixed in a dispersant, the mixture is coated on a substrate and dried to form a graphene oxide film; Step 2: according to the outer surface size of the columnar graphite heating electrode (1) of the graphitization furnace, the graphene oxide film obtained in step 1 is cut into corresponding sizes; Step 3, pre-treating the graphene film cut in step 2 by calcining under a protective atmosphere to obtain an ultra-large-sized pre-treated graphene film (2); Step 4: Load the super-large-sized pre-treated graphene film (2) obtained in step 3 into a graphitization furnace, and energize the columnar heating electrodes of the graphitization furnace to raise the temperature of the material to 2500-3100° C., thereby obtaining a super-large-sized graphitized film; Step 5: compacting the super-sized graphitized film obtained in step 4 to obtain a super-sized graphene film.

3. The method for preparing an ultra-large-size graphene film according to claim 2, characterized in that: In step 1, the coating width is 0.3-2m, and the coating length is 0.5-500m; the width of the coating substrate used is 0.5-2.5m, and the length of the coating substrate is 1-1000m; the coating is carried out using a continuous coater with a scraper, and the obtained graphene oxide film is rolled up using the continuous coater.

4. The method for preparing an ultra-large-size graphene film according to claim 2, characterized in that: In step three, an atmosphere furnace is used for roasting pretreatment, and the roasting atmosphere is high-purity nitrogen or high-purity argon, and the gas purity is greater than 99.99%. When the roasting pretreatment temperature is ≤1000°C, high-purity nitrogen is used for roasting pretreatment, and when the roasting pretreatment temperature is greater than 1000°C, high-purity argon is used for roasting pretreatment.

5. The method for preparing an ultra-large-size graphene film according to claim 2, characterized in that: In step three, the calcination pretreatment temperature is 500-2000°C. When the longest side dimension of the prepared ultra-large-sized graphene film is ≤1m, the calcination pretreatment temperature is ≤1000°C. When the longest side dimension of the prepared ultra-large-sized graphene film is ≤2m, the calcination pretreatment temperature is ≤1500°C. When the longest side dimension of the prepared ultra-large-sized graphene film is ≤3m, the calcination pretreatment temperature is ≤2000°C.

6. An ultra-large-size graphene film and a graphitization method thereof, characterized in that The graphitization method comprises the following steps: Step 1, sandwiching the super-large-sized pre-treated graphene film (2) after calcination pre-treatment between two layers of graphite paper; Step 2: The graphite paper obtained in step 1 and the pre-treated graphene film (2) are wound together and wrapped around the periphery of a graphitization furnace columnar graphite heating electrode (1) of corresponding size and specifications, and the outer edge of the graphite paper is fixed with adhesive tape; Step 3: Two annular support bodies (3) with a supporting function are mounted on the outermost part of the graphitization furnace columnar graphite heating electrode (1), and the two annular support bodies (3) are respectively located at the two ends of the graphitization furnace columnar graphite heating electrode (1), and are 10-200 mm away from the edge; Step 4: Cover the insulation material, and apply power to both ends of the graphitization furnace columnar graphite heating electrode (1) to heat the material to 2500-3100°C. After power supply is completed, the material goes through the steps of pressure maintenance, temperature reduction, and furnace discharge in sequence to complete the graphitization process.

7. The super-large-size graphene film and the graphitization method thereof according to claim 6, characterized in that: In step 3, the graphite heating electrode (1) of the graphitization furnace used has a diameter of 200-850 mm, a resistivity of 4.5-20 μΩm, and a density of 1.6-1.85 g / cm 3 , its flexural strength is 5-100MPa and its compressive strength is 10-200MPa.

8. The super-large-size graphene film and the graphitization method thereof according to claim 6, characterized in that: The two layers of graphite paper used in step 1 have an ash content of <0.5%, a carbon content of >99.5%, and a density of 1.6-1.85 g / cm 3 , tensile strength>4MPa, thermal conductivity in the plane direction is 200-600W / Mk; the thickness of the graphite paper wound on the inner layer of the columnar graphite heating electrode (1) of the graphitization furnace is 50-500μm, and the thickness of the graphite paper wound on the outer layer of the columnar graphite heating electrode (1) of the graphitization furnace is 300-800μm; the length and width of the graphite paper are 2%-10% larger than the super-sized graphene film.

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